Sodium Chlorate Production

[Al Koholic]

Well...after 2 days of electrolysing my saturated (and acidic) solution of sodium chloride (acidified with HCl) the solution has stopped bubbling even when the power is on. The liquid now appears a clear but intense green (from dissolved chlorine gas). I am using a copper cathode and a graphite anode. The power supply is the 5 volt cables from an old computer power supply. Things have been running pretty well but now it isnt electrolysing. Should I add more NaCl or what? Im new to electrolysis (with the exception of chem lab which doesnt teach you much) so I was wondering if what I have so far sounds right to anyone who has done this before. Im thinking I need to just add some more NaCl but lemme know before I mess this batch up. Thanks a bunch.
Al

[da man]

I have done this before. The first time i did it i didn't quite electrolyse it long enough, and i got a pretty poor yeild of 25 grams. The second time i did it i decided to do it in bulk so i used a car battery as a power source (30 Amps) so i could do more at a time. I gave up eventually because it was so damn tedious , and i destroyed half of my clothes from the sodium hypochlorite solution.

Anyway yes, the solution should be green, but it's not green because of dissolved chlorine its green from sodium hypochlorite which is an intermediate to sodium chlorate, which is a good sign that the rection is happening.

It's very strange that it has stopped electrolysing, are you sure that it is not the power supply that is broken, sometimes if the voltage is alot higher than the circuit is consuming it can wreck the power supply, that happened to me once. You shouldn't need to add more sodium chloride for it to continue to electrolyse, but it's good to top up with more sodium chloride to make up for what is lost as chlorine gas.

By the way do you know what the amperage of your power supply is, because it is the amperage that does the reaction, not so much volts.
Have u read wouter visser's page, it has alot of helpful information on making chlorate by electrolysis.

[Al Koholic]

Im using an old computer power supply which shouldn't fail due to over voltage since it has a short circuit protection feature (tested and works). I am running at 5 volts (12 volts makes the electrodes overheat). The 5 volt setting puts out 20 amps as well....decent hehe. Anyway....the reaction has been getting slower and slower as time passes and now I can't even tell if it electrolyses because it is so slow. Im getting little if any corrosion of the electrodes and it just seems to have stopped. Something is going on here and I dont know what. I'll wait for some responses b4 I try adding some more NaCl or HCl maybe.

[Al Koholic]

Alright.....I stirred and cleaned some of the corrosion off the top of the electrodes and now its electrolysing again. Anyway Ill keep you all posted on how it goes.

[da man]

There will be no harm done by topping up the solution with a saturated solution of sodium chloride, just top it up to the level that it started off as. I wouldn't recommend adding much HCl as it decomposes hypochlorite, which is the intermediate to chlorate!

How many grams of sodium chloride, and do you know the formula for working out how long you need to electrolyse it for?

[vulture]

If all NaCl has been converted to NaClO4 the electolysis will stop because the reaction has completed, as simple as that...
If you put on a higher voltage or add some HCl you will start electrolysing water and HCl.

Oh, if you got acces to KOH or NaOH you might try bubbling chlorine gas through a hot solution of it. This will produce chlorate, which you can then electrolyse to perchlorate. It's however a dangerous way because of the hot hydroxide solution and the toxic chlorine gas, do it outside!

<small>[ April 16, 2002, 02:09 PM: Message edited by: vulture ]</small>

[Al Koholic]

Thanks for the help guys. Anyway I had to stop the reaction due to the copper cathode corroding above the water line....the copper in solution is fine but above got too thin....need a new one which Ill have to dig up somewhere. ANyway, I think its working fine I just need to keep it going for a while longer. Oh and yes I realize that I could use the equation to figure out how long I need to electrolyse but since this is my first attempt I dont want to be too hardcore with it yet....just demonstrating its feasiblity to myself. By the way....its probably not a bad time to start thinking about how im going to spearate the chlorate from the remaining chloride. I was reading some about mutual solubility curves and temperature differences but it wasn't too clear. How did you extract your chlorate from the solution?
al

[da man]

After i had done the electrolysis for long enough i extracted the chlorate by metathesis with potassium chloride.

NaClO3 + KCl = KClO3 + NaCl

The soluble sodium chloride stayed in solution and the insoluble potassium chlorate precipitated, and i just filtered it out. If your using it in low explosives potassium chlorate is better also because it isn't hygroscopic as sodium chlorate is, which can tend to fail igniting successfully sometimes.

<small>[ April 16, 2002, 07:29 PM: Message edited by: da man ]</small>

[Al Koholic]

Ohhhh...I didn't realize that potassium chlorate was that insoluble. There must be a certain unrecovered amount which remains in solution no?

[Al Koholic]

Actually...there is about a 7% solubility in H2O for KClO3. Interesting that it is so low...

[vulture]

I wonder why you use a copper cathode, this erodes way to fast and get's easily attacked by chlorine fumes.
Most people use a steel cathode. What you could try is passivating the steel by quickly dumping it into highly concentrated nitric acid.

BTW, edit your posts instead of adding a new reply, saves a lot of space and time.

<small>[ April 17, 2002, 09:02 AM: Message edited by: vulture ]</small>

[Bitter]

"Actually...there is about a 7% solubility in H2O for KClO3. Interesting that it is so low..."

You can do the same with perchlorates too.

[Al Koholic]

Thanks for the tip man...
I used a copper cathode simply because I figured the cathode will be protected from corrosion regardless of what metal I use for it. However, it is corroding so maybe I should consider steel next time. Now I have to filter out the copper compound that has formed...copper oxide?

[vulture]

It will be copperhydroxide, copper oxide and copperchloride, the first two are totally insoluble, the last one dissolves a little bit better. The dirty green color in the solution is caused by the copperchloride BTW. I think you can remove them with normal filter paper.

[da man]

Vulture, i think that the green colour is definately from chlorine and sodium hypochlorite, i got it both times i did the electrolysis and i was using steel cathodes.

[Jumala]

The green colour of the solution isn´t from dissolved chlorine.

It is your copper electrode wich forms copperchloride with the HCL.
Copperchloride has a green colour.
I think free chlorine in the solution is impossible.
It would combine immediately with the salts to form other compounds.

[Al Koholic]

It must not be able to combine immediately due to the presence of chlorine bubbles coming off of the anode....

[kingspaz]

some chlorine dissolves in water, some however will react with it.
Cl2 + H2O <=> HClO + HCl
also
2NaOH + Cl2 ----> NaCl + NaClO + H2O
wait a sec...
2NaClO ----> NaClO2 + NaCl
NaClO + NaClO2 ----> NaClO3 + NaCl
is that right?...just a thought <img border="0" title="" alt="[Wink]" src="wink.gif" />

[vulture]

yep, the electrolysis of NaCl is a complicated multistep reaction comprised of the oxidation of the Cl from -I to +V and the side reactions of the chlorine with the water which oxidizes the NaCl and other chlorine forms in the solution.

Don't forget the chlorine formed at the electrode is in statu nascendi, which means it's much more reactive than chlorine gas.

[James]

Kingspaz, Your first two reactions look reasonable, the latter two do not. Please bear in mind however that I last took a high school chemistry course about seven years ago, so I may be (probably am) wrong.

[Pu239 Stuchtiger]

3NaOCl --> 2NaCl + NaClO3

[kingspaz]

Pu, that looks more reasonable! i say this because chlorate(V) is produced as oppsed to chlorate(III) (old name chlorite isn;t it?)

[vulture]

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">old name chlorite isn;t it?)</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">Nope, chlorite is ClO2.
To straighten things out:
Cl2=chlorine gas
Cl- = chloride
ClO - =hypochlorite
ClO2 - = chlorite
ClO3 - = chlorate
ClO4 - = perchlorate
Cl2O7 = perchloric acid anhydride, very strong oxidizer, explosive in contact with combustible material (like Mn2O7)

[Arkangel]

I have some sodium chlorate weedkiller, and in the thread that I've been looking for all morning, someone said you could remove the fire suppressant with a kitchen sieve, which I tried. I got maybe 10% of a larger white crystal, which goes great with icing sugar so I am assuming I have the pukka stuff.(is it safe to put the chlorate in a coffee grinder to make a finer powder?)

My real question though, is that since the weedkiller said it's 50% by weight, the remaining 90% I passed through the sieve contains the majority of the chlorate I'm after. (proven by the fact that it too burnt quite fiercly with icing sugar.) A few threads mention dissolving the chlorate in water, but none go into detail, so can anyone give me a little advice on this? <img border="0" title="" alt="[Frown]" src="frown.gif" />

[vulture]

You can grind chlorate separatly in a coffeegrinder with no problem.

IIRC, the chlorate solves beter in water, so dissolve the weedkiller in boiling water, wait for it to cool down. The NaCl will fall out of the solution, decant the solution and boil down.

[zaibatsu]

Don't forget that NaClO3 is heavier than NaCl, therefore the NaClO3 will look like a lot less than the NaCl. I think you may be referring to the process to convert NaClO3 to KClO3, in which case use J's page <a href="http://www.geocities.com/thejuiceuk/kclo3.html" target="_blank">http://www.geocities.com/thejuiceuk/kclo3.html</a>

[kingspaz]

vulture,
thats me your quoting isn't it?
well i know all that (althought it is useful for someone to post that in this thread).
what i said was that chlorate (III) IS the same as chlorite. at the time i wasn't sure but now i am. in chlorate (III) chlorine is in the 3+ oxidation state, oxygen in 2-.
(2*-2) + 3 = -1 (overall charge of ion)
just thoght i'd clear that up so i don't look so stupid

[vulture]

Errm kingspaz, you're really confusing me now.... :confused:
In chlorite the chlorine indeed has oxidations state +3, but I don't follow you when you say this:

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">what i said was that chlorate (III) IS the same as chlorite</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">I hope you mean chlorine instead of chlorate here, otherwise I think you still don't perfectly understand (no offense).
And saying chlorine (III) is chlorite isn't entirely correct, there also exist other compounds with chlorine in a III oxidations state.

Anyway, i think we better clear this up via email, no?

[kingspaz]

i was going to send you an email but i can't get your address so email me please and i'll explain what i'm on about! it does make sense really!

<small>[ May 21, 2002, 05:51 PM: Message edited by: kingspaz ]</small>

[vulture]

Thanks to some stupid anti-cookie software I can't login to hotmail.
My email address is: vultureacs@hotmail.com

[woo-jong]

I also tried this. After a few seconds there was odor of chlorine. I knew it is highly poisonous. So I shuted down the device. I checked the pH of the remaining solution with red litmus paper, and I found that the solution contains some bases.
The solution must be sodium hydroxide and sodium chlorate. Now, I thought about this.
When the electrolysis ends, How can I separate NaClO3 from NaOH? Separating KClO3 from KOH can be done by recrystalize. But it can't. How can I separate NaClO3 from NaOH?? Please help me.

p.s : KCl and HCl are not available for me!

<small>[ September 12, 2002, 07:37 AM: Message edited by: woo-jong ]</small>

[vulture]

If you have separated the 2 electrodes with a membrane you will produce NaOH, otherwise you've produced NaClO3. The solution of NaClO3 will be basic because ClO3- accepts a proton to some degree. This is normal.

[rikkitikkitavi]

ClO3- is the complementary base to HClO3 , a very strong acid. Thus
ClO3- doent show any tendency to accept H+ except from strong acid.

The reason why the solution is slighlyt basic is that not 100 % of the Cl2 reacts with the OH-, and therefore a slight execc of OH- is always present. This is not bad, though , because the
reaction

2 ClO- + HCLO = &gt; 2 Cl- + ClO3- performs best at pH 7-8 .

This is the prefered reaction to take place in the electrolyte bulk, giving the highest yeilds of chlorate. Other , direct oxidation reactions also takes place at the anode, but these show less efficency. Wouter´s page about chlorate is excellent!
(sorry dont have it)

/rickard

[vulture]

Rickard, HClO3 is according to my table ad medium strenght acid and can only exist in very dilute solution, so it should have a little basic tendency, no?

[rikkitikkitavi]

True, my mistake. I was to quick, pulling al acid over one comb:)

Ka (acid constant) for HClO3 is 1, meaning Kb (base constant ) is 10exp-14. It is not completely ionized , but almost. 1M has a pH of 0,2.

A 1 M ClO3- would then have a OH- conc of 10 exp-7(or rather very close) =&gt; pH = 7.000002

Just traces of OH- would knock up pH, overshadowing the effects of the ClO3-.

HClO3 is stable up to 35 % in aqeous solution,accorsing to my textbook, but it can probably vary a little.

/rickard

<small>[ September 12, 2002, 03:16 PM: Message edited by: rikkitikkitavi ]</small>

[Boob Raider]

I just found a potential source of MnO2 electrodes for chlorate production :D . AA energizer cells have to be slit open with a dremel cut off disc. Take the top and bottom off first then try to just cut off the metal cylinder with a smooth left to right (or vice versa) motion. Once the shell pops open .... you'll have a HD MnO2 tube. Oh and push out the paper roll of Zn metal, KOH, ZnO etc. in the MnO2 tube, wash it out and now to attach a wire ..... I was thinking to maybe attach a screw to the tube and wrap a wire on it.

[SATANIC]

I have been waiting to do this for a while, glad to hear there are MnO₂ electrodes to be used. they should be more reliable than most others right? (excluding platinum / titanium etc of course :rolleyes: )

what other materials have peole used, apart from steel and copper? I plan to use a large glas jar, and a car battery charger, which pumps out a fair amperage at 12 volts.

Unfortunately, I have no access to any potassium salts to convert to KClO₃ :(

I think I've got it worked out now though, can't wait to give it ago.

What sort of yields can be had ? I tried to work it out at 4 amps and came up with something like 130 grams an hour or something, after pages of calculations (rather scribbles and crossing out) That seems to be way too high.

[vulture]

Basically you can use most metals with an oxide layer which sticks to the surface, this is the case with Al2O3 for example. Now you don't want an all Al2O3 electrode because the conductivity will be close to zero. Just take an aluminium rod and electrolyse in a dilute H2SO4 solution, this will chemically passivate it and establish the desired oxygen overpotential for electrolysis.

[Boob Raider]

Wouldn't AC be better than DC, assuming 60Hz AC is used, 30 times a sec NaOH will be produced and so will Cl2 at the same electrode. Whereas if using DC, Cl is produced on one and NaOH on the other, which has to diffuse to each other meanwhile quite a bit of the Cl2 escapes.

[Marvin]

60 times a second you get oxidised compounds like chlorine, and 60 times a second they are reduced back to what they were before when the current goes the other way. To get a net oxidation of the chloride you need to react the chlorine with NaOH away from the reducing electrode (cathode). When the solution gets reasonable amounts of oxidised products, keeping these away from the cathode is critical to getting a good yeild of chlorate, one of the reasons dichromate salts are supposed to work, by forming an oxide/hydroxide film which prevents contact of the bulk of the solution with the electrode/nascent hydrogen.

Edit, additional info on electrodes.

I'm not happy with your description of passivation vulture. Aluminium cant be used as an anode, or a cathode in the chlorate cell. If you use it as an anode, you form an oxide film which is a nonconductor. To get current to flow you have to continually rupture this film with a much higher voltage. Its aluminium oxide that forms the dielectric in electrolytic capacitors, and this is formed in exactly this way.

If you use aluminium as the cathode, you get at least a partial reduction of the oxide layer, but in the chlorate cell you are forming considerable quantities of (sodium) hydroxide directly next to the cathode. Aluminium dissolves in strong bases producing aluminates and hydrogen.

Some time ago, people used electrolytic rectifiers to charge batteries. A typical setup, was a lead electrode, an aluminium electrode, and a solution of ammonium phosphate. With the current going from the lead to the aluminium, the aluminium surface is in a reduced state and conducts well. When the current attempts to reverse, the aluminium very rapidly forms an oxide layer and the conduction all but stops completely. A lot of these cells in series was required to rectify mains power, and the oxide film on the aluminium has been reported to glow faintly, presumably due to dielectric breakdown.

Passivation of steel is also not useful, becuase its the chemistry around the electrode that will determine the surface state, not any pretreatment to form oxide layers. Anodes will be oxidised, cathodes will be reduced. I dont see this affecting the oxygen overpotential at all, or that this is relavent, the post seems a little confused.

<small>[ October 15, 2002, 01:38 AM: Message edited by: Marvin ]</small>

[vulture]

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica"> Passivation of steel is also not useful, becuase its the chemistry around the electrode that will determine the surface state, not any pretreatment to form oxide layers.</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">I did not say anything about using steel, I said use metals which have an oxide layer which sticks to the surface, whereas this is obviously not the case with steel!

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica"> Anodes will be oxidised, cathodes will be reduced. I dont see this affecting the oxygen overpotential </font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">Try electrolysing KCl with Pb electrodes, then with PbO₂.
Because PbO₂ has a higher oxygenoverpotential the KCl will be oxidized, but when using straight Pb you will be producing oxygen gas.
Secondly, electrolytic passivation is used alot to prevent corrosion of metals.

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">the post seems a little confused. </font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">If you keep ripping my posts out of context they do, yeah. :rolleyes:

<small>[ October 15, 2002, 02:43 AM: Message edited by: vulture ]</small>

[Boob Raider]

Just kinda curious .... if one were to carry out electrolysis of hot and conc NaCl soln in a closed container with a bit of Pt on the roof of the vessel ...... according to me ... the Pt should catalize the formation of HCl from the escaping gasses and the the pressure caused by the gasses will increase the solubility of HCl and Cl2 in the electrolyte, thereby increasing efficiency.
Would an electrolyte prepared from bleach and NaCl be more effecient compared to NaCl in H2O.

[vulture]

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">if one were to carry out electrolysis of hot and conc NaCl soln in a closed container with a bit of Pt on the roof of the vessel ...... according to me ... the Pt should catalize the formation of HCl from the escaping gasses and the the pressure caused by the gasses will increase the solubility of HCl and Cl2 in the electrolyte, thereby increasing efficiency.</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">Nope, that won't work and it's dangerous! The Pt will split up the hydrogen gas into radicals which will react explosively with the Cl₂.
Besides, HCl has no function in this reaction, only Cl₂ and O₂, by creating HCl you will even extrude more Cl₂ gas from the solution.
Just sealing the vessel would work, but it would have to be carried out in total darkness, because the concentration of Cl₂ and H₂ will increase and the explosive formation of HCl is photoinduced. While thinking of it, if the concentration get's high enough you'll get an explosion anyways, so bad idea.

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica"> Would an electrolyte prepared from bleach and NaCl be more effecient compared to NaCl in H2O.
</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">Yes. When starting from NaCl only, NaClO is a reaction intermediate which disproportionates or get's oxidized to NaClO₃ depending on the temperature.
You might already know that boiling down a solution of NaClO will yield some NaClO₃.

<small>[ October 16, 2002, 04:46 PM: Message edited by: vulture ]</small>

[frogfot]

I'm wondering, electrolytical process of chlorate production is carried out at pH 6. This is told to give best results through following equation:
2HClO + ClO- ==> ClO3- + 2H+ + 2Cl-

I calculated pH of solution that suppose to contain 2 mole hypochlorous acid and 1 hypochlorite, using dissoc. constant of HClO (3,7E-8 @ 17*C). I got pH of 7,1.. :eek: :p :rolleyes:

Oh, damn, now I see that constant is taken at 17*C.. maby answered my own question by typing out the problem. Anyway, I will still leave this, anyone know if temperature is the main reason of pH 6?
Also, I used to think that linseed oil in anodes requires limited pH range due to corrosion in alkaline environment.

[Marvin]

This reply is a little late. :D
My apologies for not paying close enough attention at the time.


quote:
--------------------------------------------------------------------------------
Passivation of steel is also not useful, becuase its the chemistry around the electrode that will determine the surface state, not any pretreatment to form oxide layers.
--------------------------------------------------------------------------------

I did not say anything about using steel, I said use metals which have an oxide layer which sticks to the surface, whereas this is obviously not the case with steel!


I added steel as a furthur example, after pointing out why it wouldnt work with aluminium,
Iron and steel do form a passive oxide layer when anodised. Its not as impreesive as aluminium though, and it doesnt form intact naturally during corrosion as it does with aluminium.


quote:
--------------------------------------------------------------------------------
Anodes will be oxidised, cathodes will be reduced. I dont see this affecting the oxygen overpotential
--------------------------------------------------------------------------------

Try electrolysing KCl with Pb electrodes, then with PbO2.
Because PbO2 has a higher oxygenoverpotential the KCl will be oxidized, but when using straight Pb you will be producing oxygen gas.
Secondly, electrolytic passivation is used alot to prevent corrosion of metals.


I dont see the film formed in the acid bath affecting the oxygen overpotential of the cell in use, any film formed with dilute sulphuric would form in the chlorate cell anyway as the conditions are virtually the same. Lead and lead dioxide is not a useful comparason to make, since lead anodes would not passivate to lead dioxide under the sulphuric acid treatment and lead dioxide has to be electrodeposited onto anodes. Not that if it failed to form in the chlorate cell it would likley last long enough to be useful anway.


quote:
--------------------------------------------------------------------------------
the post seems a little confused.
--------------------------------------------------------------------------------

If you keep ripping my posts out of context they do, yeah.


The post seems to assume that electrolytic passivation is different from the formation of oxide layers. Maybe this is just my faulty interpretation.


That equation frogfot, is the net result of adding all the equations that are actually happening together, so it cant be rate limiting. Rate is what is important here, rather than equilibrium, since redox reactions dont have much of an equilibrium to speak of.

[T_Pyro]

I've been looking at a few designs for chlorate production cells, but they all raised a question in my mind. The production of chlorate depends on the formation of hypochlorite first, which in turn depends on the dissolution of Cl2 in water. However, in all the cell designs, there was no provision to prevent the escaping of chlorine gas. Due to this, won't the efficiency of the cell get reduced? Will the presence of a bulb above the anode increase the efficiency by minimising the loss of chlorine to the atmosphere?
Also, if the hydrogen gas formed at the cathode and the chlorine gas formed at the anode are allowed to mix, they'll form HCl gas, which will immediately get dissolved in the water due to its high solubility. Won't this also reduce the efficiency of the cell?

[frogfot]

Just keeping the temp at least above 30*C will give you minimal chlorine loss. At recommended current dencities there are no chlorine bubbles evolved, they dissolve pretty fast.
I use an air-tight cover on the cells, but thats just so I can filter the exhaust gases, letting these gases back in electrolyte would be to complicated and besides lost is not that big.

Gaseous hydrogen will not react with dissolved chlorine.

[T_Pyro]

My cell runs at a temperature of about 40*C. I've read that high temperatures cause the electrodes to decompose faster, but mine seem to be holding, so I'll just let them run on their own without any ice/water bath. The current density at the anode is approximately 90.95 mA/cm2 . However, the chlorine starts bubbling out of the solution, so I'm not sure exactly how much of it gets dissolved...

Someone earlier had mentioned a green colouration in the electrolyte. I've experienced the same, but although I'm unsure as to what it exactly is, I'm sure that it's not a simple salt of copper (the solution tested negative for all the Cu ion tests I did on it), and it's not due to the chlorine gas either, because it persists (and in fact intensifies!) after boiling the mixture. It is possible, however, that some coordination salt of copper is formed, which would not show up in any normal tests for Cu ions.

[Pyrophoric]

Has anyone tried using magnetite coated iron electrodes in chorate production? - i've read that an even, black magnetite coating may be produced on iron by immersing it in hot, concentrated NaOH/NaNO3 solution (not without its dangers). This process is usually used to produce thin magnetite layers on metal parts for its asthetic and corrosion resistant properties and hence probably wouldn't last very long in a stongly corrosive environment. I had also read somewhere on Wouter's site that magnetite is fairly rapidly consumned in the cell, however it might compare favorably to using straight carbon (especially if the electrode could be eaily rejuvinated by a hot-dip process).
Scrap that - I now remember that there are more modern methods for depositing magnetite on to iron - using electrolytic processes and secret chemical mixtures (at least i haven't been able to find any info on their compostion - trade secrets). The deposit is supposed to be of superior quality and thickness over the hot-dip method (probably giving supirior corrosion resistance and the possibility of being able to plate on to an inert substrate).

[Marvin]

I thought I'd read somewhere that magnetite electrodes were usually cast, unlike lead dioxide which can be plated. It also strikes me that the iron electrode isnt so much being coated, as etched. Maybe you should try electrolysing some Iron (III) salts and see if you can get anything to form on the anode.

[Bacon46]

This post is in response to a request for information made in the thread linked below. I thought it would be best to post the information in a thread more closley related to the topic and cross link them.

http://www.roguesci.org/theforum/showthread.php?t=294&page=3

The sodium chlorate produced in this cell was use to produce potassium chlorate.

I am assuming the reader has basic knowledge of NaClO3 production via electrolysis of H2O/NaCl and precipitation to KClO3 using a saturated solution of H2O/KCl. I have detailed instructions on the process but posting it would be plagiarizism. I have forgotten where I acquired the information and am unable to give credit to the author. This information is available on the internet and elsewhere on this forum.

4 Gallon Chlorate Cell Specifications

• Cell Body: 5 gallon plastic paint bucket

• Anode: 1 ¼”x 1 ¼” x 16” solid graphite bar coated with boiled linseed oil to slow corrosion. 10” of the anode was submerged. I purchased a graphite bar large enough to make 4 anodes this size from a local junk/scrap dealer for $5.00. The linseed oil can be purchased at any hardware store in the paint department for $4.00 or $5.00 per quart. I brushed it on, let it soak in for a minute or two, wiped off the excess and let it dry while I worked on the electrical connections.

The electrical connection at the anode was made by drilling a 5/8" (15.875mm) hole a couple of inches from the top of the anode and inserting a 12" (30.48cm) long piece of 1/2" (12.7mm) copper tubing. The copper tubing spanned the bucket allowing the anode to hang so that the bottom was just above the bottom of the bucket. The positive clamp of the battery charger attaches to the copper pipe.

• Cathode: 4” x 5” x 1/16” solid copper plate hanging from a #12 solid copper wire running through a hole in the plate. This wire wrapped around another piece of copper tubing spanning the opposite side bucket and the negitive clamp of the battery charger attached to this pipe. The plate to wire connection was kept above the electrolyte.

• Electrolyte: 4 gallons (15.14 liters) H20/NaCl. I dissolved approximately 13 lbs (5.89 kg) of NaCl in 4 gallons of water. I purchased in the NaCl in the form of water softener salt at the local hardware store. A 40lb bag was less than $5.00. 13 lbs of NaCl will not completely dissolve in 4 gallons of water. I used a clean white cotton tee shirt to filter out the un-dissolved solids after the electrolyte had cooled to room temperature.

• Power Supply: 12 VDC, 10 amp, battery charger modified to output 6 VDC by disconnecting one leg of the transformer. Voltage at the cell was 5.4 VDC

• HCl Drip: 6.5ml of 2% HCl

Estimated Production
Chlorate Production @ 100% Efficiency
• Per Hour: 7.94 gm (0.25oz)
• Per Day 190.62 gm (6.00 oz)
• At completion (44 days) 8.27 kg (18.23 lb)

Chlorate Production @ 75% Efficiency
• Per Hour: 5.95 gm (0.2 oz)
• Per Day 142.97 gm (5.04 oz)
• At completion (58 days) 8.27 kg (18.23 lb)

Actual Production on the First Run (37% Efficiency)
• Run Time: 28 Days (Should have run another month)
• Total Production: 4lbs (1.81kg)
• Production Per Hour: 2.69 gm (0.095oz)
• Per Day 64.56 gm (2.27 oz)

Notes

Back yard chlorate production is inefficient but it is definitely less expensive than buying it from a chemical supplier and you don’t wind up in any ones database as a potential terrorist.

To make up for the inherently inefficient production of back yard chlorate cells I use a 5 gallon cell. Starting a cell this large requires a fair amount of labor and a large stainless steel cooking pot for dissolving 13 lbs (5.89 kg) of NaCl in 4 gallons of water. I had to do this in 2 gallon batches. You want to make an extra gallon or two of electrolyte to make up for losses due to evaporation.

Unless you have a room with an exhaust system operation of the cell needs to be done outdoors. The chlorine gas emitted from a cell this size is dangerous, especially at startup when the electrolyte is not up to operating temperature. It is best to start the cell on a breezy day. This will prevent the chlorine gas for accumulating and killing someone or drawing the attention of your neighbors. Once the cell reaches operating temperature most of the chlorine dissolves in the electrolyte and the smell is only an issue when you are within 20ft of the cell. A respirator is recommended when you are any closer than that. If you don’t have a respirator, hold your breath, especially when topping off the electrolyte or adding acid.

Electrolyte temperature and Ph are the two factors that were hardest for me to control. The closer you keep these factors optimum the higher your production will be. My biggest problem was with temperature. I ran the cell above in January and February. I live in the desert southwest where winter temperatures rarely go below freezing and daytime temperatures are in the 70s and 80s but I still had a problem with the temperature being too low. I had the anode and electrode as far apart as possible. Dropping the voltage from 5.6vdc to 4vdc probably would have helped but I was too lazy to install a rheostat.

I controlled the ph with a drip system using 3% HCl. A two foot section of 1 ¼” PVC pipe reduced down at one end to a 3/8” hose barb. I attached a piece of 3/8” ID vinyl hose to the hose barb and installed a devise that pinched the hose to regulate the flow of acid to a drip rate of approximately 6.5ml per hour. The bottom of the PVC pipe containing the acid needs be installed above the top of cell. (No Shit)

As the cell runs NaClO3 and graphite from the anode will accumulate at the bottom of the cell. Once or twice during the run cycle of the cell I filtered the entire contents of the cell through densely woven white cotton cloth. I then took the NaClO3 / graphite mixture from the filter and added it to just enough hot water to dissolve the NaClO3. I poured that solution through a fiberglass building insulation filter to remove the graphite and used the resulting clean NaClO3 solution to top off the cell.

After 28 days I shut the cell down. I filtered the electrolyte through building insulation, boiled off the hypochlorites and adjusted the ph to between 8 and 9 by adding very small amounts of NaOH.

When boiling off the hypochlorites do not use anything other than a stainless steel pan. I accidentally used a chrome plated pan. The electrolyte removed the chrome from the pan and reacted to produce a dark brown mud like substance and prevented the electrolyte from boiling. It scared the hell out of me. I thought I had ruined it; and so close to the finish line.

This “Mud” was easily removed by filtering and I was then able to successfully boil off the hypochlorites. Once the hypochlorites had been boiled off and the electrolyte had cooled to room temp I added a saturated KCl/H2O solution. To make this solution I used 127g of KCl for every 100g of NaCl that I had started with. In this case that was 7.5kg (16.5 lbs) of KCl dissolved in as little water as possible.

After adding the KCl/H2O solution to electrolyte a little over 4 lbs (1.8kg) of KClO3 precipitated.

One re-crystallization was sufficient to produce a very pure batch of KClO3.

It did not quite produce one pound per week but it was close.:D

I am preparing to move to a much more remote part of the country where the smell of a large chlorate cell or two won’t draw any attention. I will let the next one run full term and do something to control the temperature. Hopefully I can get the efficiency closer to 50%.

[nbk2000]

There's no attached drawing.

And why do you mention potassium chlorate? Did you mean to mention potassium chloride somewhere in there?

[Bacon46]

There's no attached drawing.

And why do you mention potassium chlorate? Did you mean to mention potassium chloride somewhere in there?

The drawing wasn't really necessary so I deleted that and cleaned up the rest of it.

That's two fuckups in a row!:o

[Voodoo0744]

I've been told to post because I lurk too much.

I've been trying for a few hours to find solubility of some random chemicals in my chlorate veggie-cide. I'd like to take out the crap in it and double-decomp with Pot. Chloride.

39.8% NaCl03
40% Na2B2O4 (Sodium metaborate)
0.76% Simazine (another veggie killer)
5% Prometon
14.44% inerts (Probably something like dextrin, it's pelleted.)

My theoretical extraction procedure (outlined)
2.5 lbs into 454Ml. H20 at 20 degrees celcius. (70 degrees F.)
Filter out what doesn't dissolve with stirring after 3 or so minutes.
cool another 10 or so degrees.
measure out 577g. pot. chloride
Add Pot chloride
filter chlorate
boil down to get a bit more chlorate
and so on with burn testing/drying/yea.

it sounds simpler than what I wrote it as, but mostly what I'm looking for is tips on purification.

Thanks a lot. :)

Oh yea and I'm also not sure of the molecular amount needed for the potassium chloride to ppt. the KCl03, so I made it around what I though would make equal to what I wanted (one pound 454g.)
Everyone says it differently I've heard 1.27 grams potassium chloride for every grams of sodium chlorate you want to convert, but I've heard a lot of random stuff.

So I guess if 1.27 KCI is right, that'd be 577 grams I think( A little less than that actually, but come on.)

[Oss]

From one lurker to another Voodoo, let's hope I can help! If anyone wants to verify and/or correct my maths/theory feel free.

I'll start with this line:

..I've heard 1.27 grams potassium chloride for every grams of sodium chlorate you want to convert...

In haste I guess you mistyped that (taken from wfvissers' site). You want 1 mole of KCl for every mole of NaClO3 you believe you have (not NaCl) so..

Molecular weights (using semi-accurate periodic tables):
NaClO3 = 106.5
KCl = 74.5

You need to add 70% by weight of KCl for your NaClO3. [ 74.5 / 106.5 ]

In your theoretical example, you use (2.5lbs) 1.13Kg of 'veggie-cide'

1130g Veggie-cide = 450g NaClO3
(at 39.8% content according to your first post, which gives you 449.74g. We'll call this 450g for simplicity)

You need 70% of this weight in KCl to convert all the NAClO3.
70% of 450g is 315g of KCl to make your KClO3


After all that - onto the purification. I'm having little trouble getting solubility data for your main contaminant (Na2B2O4). As far as I can gather, the borates are highly soluble, so we'll go with that assumption until more information is obtained.

I would start with dissolving the veggie-cide in minimal water, heat it as you do so.
Put in the KCl - I don't believe making it into a saturated solution before adding will be necessary here.

KClO3 solubility in water is low, so you might (only might) see crystals come out of solution at this point. Either way you need to cool it now.
Personally I would let it cool to room temperature (see what crystals form) then cover it and put it carefully into your freezer for half an hour.

The NaCl that will form (and any leftover KCl) is soluble to about 35g/100ml water at 0 degrees C (32F). KClO3 solubility at this temperature is only 3g/100ml.

Once you have the solution nice and cold, you should see a pretty landscape of crystals. Filter these off, optionally washing with ice cold water (you had this cooling in the freezer, of course :)

Take a small sample and dry it. Make a 50/50 mix of sample and sugar and see how it lights. If it performs adequately but the flame is yellow or very washed out purple then purify again. A quick dissolving/cooling/filtering cycle - don't go mad with the water.

Ok think that's us. I'd be tempted to say the electrolysis processes might be easier with less contaminants to get rid of, also starting with KCl means no sodium in the mix!

* Mods - I've no doubt my English will be checked. It perhaps rambles a little with lack of practise in writing.

[nbk2000]

Let's not forget that the Sodium Metaborate will also react with the KCl, so you've got a competition on for those potassium atoms.

[Oss]

It's always the most obvious things we miss, eh? It's as well someone checked, thank you.
As there is a source of KCl, electrolysis gets my vote - especially as all the details are known.

There is something about using/converting sodium metaborate for use in hydrogen fuel cells but I couldn't find much more out. It may well be irrelevant.
Lack of chemistry knowledge is an obvious problem for me, but I really should have spotted that issue.

[Bacon46]

Here are links to the solubility data of the chemicals you listed.
It wasn’t too hard to find.

Sodium Metaborate
http://www.borax.com/pdfs/dist/MSDS_Sodium_Metaborate_4_Mol.pdf


Promotone
http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC35130#Water


Simazine
http://www.epa.gov/safewater/dwh/t-soc/simazine.html

Dextrin
http://www.skylighter.com/msds/dextrin.txt

http://www.adhesives.co.in/products.htm

[Voodoo0744]

thanks a lot for your help all you guys Oss too for your large, informitive post. I didn't know the correct Moles needed for precipitation, I appreciate it.

Bacon46 Thanks a lot for those links theyre really helpful, just on question though; In the Na Metaborate link it states it solubility in h20 at 20deg. C is 31%..? does that just mean 31 g./100mL.? Thanks :)


thanks NBK also, I thought about that and I guess that confirms I'm gonna have to find some way around it.


PS: I have two 800mL. chlorate cells, but this is the first time I've seen OTC chlorate so I grabbed a sixty-dollar bag. :( It was a hefty price, but with around 10 lbs. of the good stuff in it, its worth it to me. Thanks guys!

[Oss]

Voodoo, no problem. Even the Merck Index was surprisingly sparse on info.

Bacon46 - I came across a similar datasheet as you provide, but like Voodoo I couldn't resolve the 31% solubility statistic; hence its exclusion. Someone has kindly given their option and I now believe Voodoo is right - 31g/100ml H2O.
Good news then! KClO3 solubility is lower and drops to almost 3g/100ml at 0degC (32F).

I'd definately give it a shot. Let us know how it goes :)

[Voodoo0744]

I finished the first part.
I used 250grams of herbicide and 130ml of ice cold water.
I stirred in the chemicals and I think I have a NaCl03 solution sitting in the garage.

I was thinking the best way to precipitate KCl03 would be to heat the NaCl03 solution to completely dissolve it, add 75 grams Potassium Chloride in solution, then chill it to 0 deg. C.

after that filter the ppt. and test it.

what do you guys think?

[Oss]

Sounds a fair plan to me, ice cubes and salt on standby! :)

[Voodoo0744]

Well I never really got around to attempting the filtration, although I did add the Potassium Chloride.

I think I'll ditch this batch, and try another with very hot 91% Isopropyl alcohol. I think that NaClO3 does not solute in alcohol, I know for sure KClO3 doesn't. I'm hoping that the prime conaminant; Sodium Metaborate does however solute in alcohol, thus separating the two.
After the alcohol I would filter and shake with a bit more hot Isopropyl Alcohol to dissolve any more Metaborate. I would leave outside over a slight heat to evaporate the alcohol, add to a solution of room temp. water, add Potassium Chloride, shake, filter boil down.


The one problem is knowing the exact amount of alcohol, but that can be determined with math once I try this whole thing.

Second option:
This is kind of getting expensive in this one but oh well.

If NaCl03 does afterall solute in the alcohol then I'll change it up a bit.
Add double the amount of required potassium chloride assuming the sodium ions in the chlorate and metaborate attach to them. Convert it all. If the metaborate is soluble in the Isopropyl, it'll stay in solution, while the strongly insoluble KCl03 precipitates. Shake, filter, boil down...

If none of this works anybody with info on solvents Na/KClO3 are soluble in and/or Sodium and potassium metaborates are soluble in it's all very appreciated! thanks :)

[stupid939]

From what I could find (or should I say not find), sodium metaborate is not soluble in alcohol. I did not find much info about it on the web, and the merck index only lists its solubility in water.

[Voodoo0744]

Yea neither could I, a few forum members looked for solubility info but found only info on water solutions with metaborates, and very little.
It seems like a very soluble ingredient to me, and alcohol being a solvent I'd hoped it'd be able to solute.
I don't know much about metaborates though.

[209]

I was just looking over some of the posts that talk about the chlorine gas. I just tried the electrolosis of NaCl just ten minutes ago and noticed a very odd smell coming off the beaker.

I have never had any exposure to Cl so I didn't know what it is. Then the smell got really strong and I went out to check it and the two electrodes stopped bubbling completly. The smell was quite strong and I freaked and dumped the solution. Was this chlorine gas? I WILL NOT be doing this in my garage again.

[Voodoo0744]

Chlorine gas smells like (but is a lot stronger, more pungent smell than) cheap bleach, clean pool water, or pool cleaners.

What was your setup like? (Electrode material, electrolyte concentration, voltage, PH, DC or AC, ETC..)
If the electrodes stopped bubbling you may have shorted your setup, but it's not likely if it was done right or close to correctly. Chances are one thing went wrong and you can fix it it 5 minutes :) or maybe your cell just made a lot of gas at the start?
Don't give up, this method takes quite awhile but what goes in comes out much better, it's worth it if you're patient.

I'm sure you know there are a bunch of methods for chlorate production, trying all of them will help you find your favorite. Plus it's more science and more chlorates ++

[209]

My setup is 12V @700Ma. I think this may be WAY to much but I am not sure. But the smell was definatly one of pool cleaners and chloriney chemicals. The electrolosis lasted for all of ten minutes and I am not sure what condition the tranformer is because I unplugged it, dumped the solution and got the hell out of there. I was in my garage for all of 30 seconds.

[tmp]

12 volts is too high unless you setup 2 cells in a series. As for the chlorine
smell, get used to it. Chlorine is more of an irritant than a poison in low
doses. I don't have the luxury of a garage so I run it in my bedroom next to
an exhaust fan. Despite good venting from the fan, some chlorine does make
its way back to my nasal passages and my bedroom smells like bleach.
But I want my perchlorate and the smell is a small price to pay - no worse
than bleach. Many years ago I had a parakeet in my bedroom. I kept her
there because of my 2 cats. She lived 11 years despite smelling chlorine on
occasion. BTW, her life span would've been a lot shorter if the cats had
gotten to her !

[Voodoo0744]

Yea man. Think of the parakeet. :)

A good idea ould be to get another chord with some clips on it and attach it like this: positive transformer power chord to cell#1 anode, negative transformer power chord connected to cell#2 cathode, the the third chord clipped to cell #1 cathode and #2's anode. That gives each cell 6 volts which isn't too high, you'll still get some smell at the beginning and the end though.
I did this with 2 Jiff marshmellow fluff jars and now they work fine for Cl03/04:P

A great site for research on this topic is Visser, he is a bright and well renowned chemist. He has instructions for this process in detail :), just search visser chlorate or something.

[Bugger]

Bacon46 or anyone else does does not specify what DC voltage between the electrodes is appropriate for producing pure NaClO3 in solution from NaCl solution. What is it? This is important, because other possible products at differing voltages are NaClO, NaClO2, and NaClO4. He mentions a "battery charger" as a DC source; they are either between 6 and 7 volts (for 6-volt lead-acid batteries), or between 12 and 14 volts (for the usual 12-volt car batteries), or, for truck batteries, between 24 and 30 volts.

[Voodoo0744]

The appropriate optimum voltage is 4.5-5.5V

It can be a little higher with some loss of efficiency and increased anode corrosion.

[Oss]

I'm a little past it, but you could investigate this line of thought..

sodium metaborate can be electrolysed to boric acid and sodium hydroxide.
sodium hydroxide is used in the sodium chlorate production process (electrolysis of sodium chloride).

Boric acid is not very soluble in water - about 5g/100ml water according to wikipedia.

Apart from this, I think more input is needed from someone with better chemistry knowledge.

For info, idea came from this:
http://www.hydrogen.energy.gov/pdfs/progress05/vi_b_1_wu.pdf

[Bacon46]

Bacon46 or anyone else does does not specify what DC voltage between the electrodes is appropriate for producing pure NaClO3 in solution from NaCl solution. What is it? This is important, because other possible products at differing voltages are NaClO, NaClO2, and NaClO4. He mentions a "battery charger" as a DC source; they are either between 6 and 7 volts (for 6-volt lead-acid batteries), or between 12 and 14 volts (for the usual 12-volt car batteries), or, for truck batteries, between 24 and 30 volts.

In the same sentence that "Mentions a battery charger" it also metions that the charger was modified by disconnecting one leg of the transformer so that it's output was 6VDC. It also mentions that the voltage at the cell was 5.4VDC.:D

I also stated it was a 10amp charger. That is incorrect. It is a 12 amp charger and I set it to run at its maximum output. I don't have an accurate means to measure DC Amps at the cell, so I don't know how many amps where actualy being drawn. The needle on the charger was pegged.

As stated by VooDoo0744; For maximum efficency, voltage should be between 4 and 5VDC.

The formula I use for current is 2 amps per 100ml of electrolyte. I was way below optimum on the current but I'm not ready to sacrfice my welder for chlorate production just yet!

[Voodoo0744]

You know what Oss I had given up with that but I think you just saved the idea, I could electrolyze the solution of weedkiller till boric acid precipitates (which I use in my nitrate flash to prevent random combustion), drown the solution in methyl or isopropyl, both of which Im sure NaOH are soluble in and precipitate the insoluble chlorate.
And another plus, some of it would be perchlorate due to electrolysis of a chlorate to start with.
Maybe I could use one of my chlorate cells to do it.

There are some things I'm thinking about though: Voltage, length of time, corrosives...I wonder if stainless steel forks and graphite rods resist alkali. I could acidify the mixture when it tests abnormal PH though. Keeping it at 6 or 7 should be okay...voltage I guess will just be 4.5v and hopefully it'll work...as for timing? I guess I could try to just see when it stops precipitating solids (boric acid).

It might work, unlike my other plans for the weedkiller. Otherwise I'm just going to let it sit till I have some veggies to murder. :p

[Bacon46]

I was finaly able to track down my source of reference for chlorate electrolysis information. It's Wouter's Practical Pyrotechnics.

The link is below is to a page on his site that gives detailed information on electrolysis of chlorates and perchlorates.


http://www.wfvisser.dds.nl/EN/chlorate_EN.html

This is a link to drawings of the 4 gallon chlorate cell I mentioned in the previous post. Sorry, the images are small.

Note: The PVC cap shown on the HCL drip has to have a vent hole drilled in it

<a href="http://img531.imageshack.us/my.php?image=chloratecellvr5.flv"><img src="http://img531.imageshack.us/img531/6137/chloratecellvr5.flv.th.jpg"/></a>

[tmp]

Bacon46, I saw Wouter's page years ago and downloaded a copy of it onto
the FTP. It's a GREAT page on the how-to of chlorate and perchlorate
production. This is another great site:

http://www.geocities.com/CapeCanaveral/Campus/5361/basechem.html

Voodoo0744, have you tried finding some oldtime roach killing powder ? The
stuff I used to have was pure boric acid. And yes, it did a good job killing
the little bastards although it could be a bit messy.

[Voodoo0744]

Nope never used the roach stuff, I never had to have much (I add 1% by weight to nitrate flash) so I just go to the pharmacy and buy 4oz. for $3 once in awhile.

I guess if this electrolysis works I'll get free Boric acid though. =P

[Cobalt.45]

"Enoz" brand "Roach Away". 99% boric acid, sold at WalMart, same aisle as the bleach. ~$4.50/lb.

[Voodoo0744]

Well I guess I'll just go grab some of that stuff when I run out of the new bottle I just got, it usually last 8-10 months though. I don't ever really get to actually do or use my pyro stuff, neighbors...police....old people....ETC...

[Bacon46]

I fired up a new chlorate cell on the ninth of this month. Below are the cell specifications and a couple of questions I have concerning replacment of H2O lost due to evaporation.

Electrolyte
• 8 liters (2.11gallons) of H2O
• 3.2 kg (7.05 lbs) NaCl
• 24g (0.84oz) K2Cr2O7

Electrodes
• Anode: 3.175cm x 3.175cm x 25.4cm Graphite coated with boiled linseed oil. 15.25 cm of the anode is submerged, totaling 203.75 square centimeters of submerged anode surface area. Using 30mA per square centimeter as a target for maximum anode life, optimum current would be 6.1 amps. Because the anode is large and dense I am not worried about excessive anode deterioration. I decided to run at approximately 12 amps.
• Cathode: Standard ¾” copper pipe

Power Supply
• 12 vdc / 12 amp, automotive battery charger, modified to output 6 vdc by disconnecting one leg of the transformer. The end result is 4.6 vdc @12 amps at the electrodes.

Notes
The 24g of Potassium Dichromate was added on 9/12/2007. Three days after the cell was started.

Operating temperature of the cell varies from 52o C (125.6o F) at night to 60o C (140o F) during the day.
Loss due to evaporation is approximately one liter per day. As of 9/13/07 I am replacing this with a saturated H2O / NaCl solution (Fresh electrolyte). The instructions that I have for operating a chlorate cell suggests that I do this to prevent the NaCl level from dropping below 10% thereby preventing the formation of perchlorate. I have done this in the past with larger cells and been successful, but it seems like a waste of time.

In previous cells as with this one, replacing H2O that has evaporated from a saturated NaCl / H2O solution with more saturated NaCl / H2O solution causes a large amount of solids to precipitate to the bottom of the cell. Saturated is saturated! In my last cell when the solids had gotten to be two to three inches (5cm to 7.5cm) deep in the bottom of a 5 gallon (19 liter) bucket I filtered them from the electrolyte, re-dissolved it in clean H2O and used this solution to replace evaporation loss. This cell was run in the winter and the operating temperature never climbed above 40C (104F). The loss due to evaporation was closer to 500ml per day.

At 100% efficiency my current 8 liter (2.11 gallon) cell would need to run for 30 days to completely convert the original 3.2 kg of NaCl to NaClO3. If I continue to replace evaporation loss with fresh electrolyte, at the current rate of evaporation I will have doubled the amount of NaCl in the cell in eight days. This would eventually turn the electrolyte to a paste or heavy slurry. This is obviously unacceptable so I will do the same thing I did on the last cell and filter out the precipitant, dissolve it in clean H2O and use this to make up for the evaporation losses. This really is a pain in the ass.

My question are:

Does anyone see any reason to ever replace H2O lost to evaporation with fresh electrolyte?

Since I have already created a good deal of precipitant in this cell, is there any advantage to cleaning the cell on a weekly basis, re-dissolving this precipitant in clean H2O and using this to replace the evaporation losses?

The links below are to images of the current cell. I know they aren't necessary to answer the questions but I didn’t think it could hurt.


http://img210.imageshack.us/img210/4217/8literchloratecellqm6.th.jpg (http://img210.imageshack.us/my.php?image=8literchloratecellqm6.jpg)

http://img88.imageshack.us/img88/9630/cellpowersupplyds8.th.jpg (http://img88.imageshack.us/my.php?image=cellpowersupplyds8.jpg)

[Charles Owlen Picket]

That appears to be a pretty good presentation & looks quite workable. To address the question of replacement of fresh electrolyte it would seem that ratio and proportion are inherently valuable to the process thus I would replace evaporated H2O. Have you attempted potassium chloride (available as water softener product- very inexpensive) in this process instead of NaCl?

[Bacon46]

Have you attempted potassium chloride (available as water softener product- very inexpensive) in this process instead of NaCl?

From Wouters Practical Pyrotechnics:
When KCl is used KClO3 crystallizes during operation of the cell due to its relatively low solubility. To separate the KClO3 from insoluble impurities the electrolyte has to be filtered hot. The solution usually takes quite a long time to pass through the filter and if it cools during this time the KClO3 crystalizes and clogs the filter.

Once the I shut down the cell I create a saturated KCl/H2O solution using 127g of KCl for every 100g of NaCl in the electrolyte. I use this to precipitate KClO3 in a Metathesis Reaction.

[tmp]

Fresh electrolyte should keep the chloride level above 10%. Below 10% NaCl
and above 40 C operating temperature tends to accelerate the deterioration
of carbon or graphite anodes. I noticed in your post that you're running
between 52 C and 60 C. What is the wear rate on your anode ?

[Bacon46]

The amount of graphite suspended in the electrolyte in one week of operation would indicate fairly rapid deterioration. I didn’t record accurate measurements of the anode prior to starting the cell. I haven’t seen my dial gauge in months, but there is no visible change in the size of the anode.

The anode is large and very dense and graphite is very easily filtered out of the electrolyte so I am really not too concerned with the anode deterioration rate. Even at the current rate of deterioration I would estimate this anode could survive at least six months of continuous operation. I also have enough material on hand to make 30 more anodes of the same size.

I apologize, I phrased my questions in my previous post incorrectly. :o I know that keeping the NaCl above 10% will extend anode life, but I cannot continue to use fresh electrolyte to replace the H2O lost in evaporation. The electrolyte will turn to paste. I have already switched over to just replacing the H2O with more H2O.

My questions should have been:

Is there any advantage to removing the existing precipitant from the cell on a regular basis (weekly), cleaning it, re-dissolving it in H2O and continuously recycling it through the cell? Could doing this increase the yield?

Or

Should I just remove it from cell altogether?

Or

Should I just leave it in the bottom of the cell and not worry about it until it’s time to process the electrolyte?

I would estimate the amount of precipitant currently in the cell to be just over 1kg.

[ETCS (Ret)]

Bacon46,

As you've verified with your cell, by keeping the current flow down to a reasonable level consistent with the surface area of your anode, the carbon anode will last quite a long time.

Have you evaluated the makeup of the crystals which are precipitating to the bottom of your cell? I suspect, based on my own experiences, that a good percentage of the crystals are chlorate. It probably would do no harm to let them accumulate on the bottom of the cell as long as they're not in the way.

It is also possible, that you may be getting some perchlorate crystals in the precipitate as well. If the anode is emitting oxygen and chlorine together then some perchlorate will form.

When the cell is "lit off" with a fresh batch of brine the chlorine smell should be quite strong. As time goes by the smell becomes less intense and you'll notice that more of the anode bubbles rise to the top of the solution indicating oxygen production and some perchlorate production as well.

Yes, as you've deduced, adding water alone is preferable to adding new brine solution for the reasons you've mentioned.

Now, if you can devise a way to position your electrodes completely under the brine solution so that you can cover the top of the cell you'll reduce the water lost to evaporation greatly.

I like to use polyethylene bottles with the carbon rods and steel rods pushed through the sides horizontally near the bottom of the container - carbon rods positioned over the steel rods which are about 1/2 inch to 1 inch beneath them. Connections to the power supply are then made to the rods outside the cell which is much cleaner. Let the cell perc for the requisite amount of time, adding water into the top when needed, then dump for processing and refill for the next batch.

Ah, electrochemistry is so much fun!

[Bacon46]

After 10 days of running, to slow the evaporation rate, I did install a 3/16” thick clear acrylic cover on the cell. The loss of H2O from evaporation decreased dramatically. An expected side affect was the electrolyte temperature rose to between 60C (140F) at night and 70C (160F) during the day.

The higher temperatures, combined with the reduced evaporation, decreased (practically eliminated) the amount of NaCl or NaClO3 precipitant in the bottom of the cell. It also increased the anode erosion rate but as I stated in a previous post, I am not all that concerned with that.

The higher tempratures should also decrease the the amount of HCl necessary to maintain the pH. We'll see.

[Alexires]

Bacon, I would be inclined to believe that almost all the precipitate is NaClO3. Why not use a container (http://www.grainmills.com.au/images/p1000002.jpg) that has a tap in it at the bottom. That way, when you have a heap of precipitate, you can just open the tap and leech it off.

You all know the type of container I'm talking about. Holds about 15-20L, normally opaque white or black with a tap in the side near the bottom and a 10cm diameter lid.

Adapt one to be a chlorate maker, and then you control evaporation as well as the issue of precipitate.

[Bacon46]

Originaly posted by Alexires Bacon, I would be inclined to believe that almost all the precipitate is NaClO3

I would agree if I hadn’t been replacing the evaporation losses with a saturated NaCl / H2O solution and the precipitant hadn’t occurred in the first week of the cells operation. When I first started the cell I made 16 liters of electrolyte, double the amount required to fill the 8 liter cell. In 10 days of operation I had added all of the additional electrolyte to the cell to compensate for evaporation losses.

Prior to installing the cover, the electrolyte temperature went as low as 52C (125.6F). At this temperature the additional NaCl just couldn’t stay in solution. Some of the precipitant may have been NaClO3 but I think most of it was NaCl.

With the cover in place the temperature is staying close to 65.5C (150F) most of the time. At that temperature all of the NaCl and NaClO3 is being held in solution, approximately 6.4kg (14lbs) in 9 liters of H2O with no precipitation. When I shut the cell down precipitation starts as soon as the temperature drops below 40C (104F). Now that the cell has been running while I would guess most of this precipitant is NaClO3. When it comes time to process the electrolyte I will add enough water to hold everything in a saturated solution at 25C (77F) then react that with a saturated solution of KCl / H2O.

After covering the cell I also modified the HCl drip to accommodate the reduced demand for HCl. I purchased an I.V. Administration set with a drip volume of 10 drops per ml. I switched from 3% HCl to 1.5% and set the drip rate to approximately 24ml per hour; this keeps up with the evaporation losses. Now I have a pretty much maintenance free cell. I check the pH every couple of days, and I shut it down once a week to filter out the graphite created by the anode deterioration. I hate the look of all that black shit floating around. Next time I will order an I.V. set with an output volume of 60 drops per ml. At 10 drops per ml I have this one running almost as slow as it will go

Originaly posted by Alexires You all know the type of container I'm talking about. Holds about 15-20L, normally opaque white or black with a tap in the side near the bottom and a 10cm diameter lid.


I think I have one of the containers (http://img218.imageshack.us/my.php?image=5galcontainereg1.jpg) you are referring to. It holds 5 gallons (18.92 liters) and the cap is threaded to accept ½” NPT. I planned on using it to store the processed electrolyte from this cell for use in the next one. I would really like to get a 10 liter clear glass container just so I can see what was happening at the bottom of the cell while it’s running.

Link to image of cell with modified HCl drip
http://img233.imageshack.us/img233/8053/8litercellwaciddrip2ud3.th.jpg (http://img233.imageshack.us/my.php?image=8litercellwaciddrip2ud3.jpg)

[Alexires]

Bacon - Fair enough, forgive my error.

Yes, that container is pretty much what I was thinking of. Couldn't find a picture for the life of me though.

I like your set up though, especially the HCl dripper.

Have you thought about trying to cool the set up to stop anode corrosion, because 65.5ºC is pretty damn high for a cell. Perhaps just have a fish pump (with filter removed) pumping the solution through a PVC tube for a metre or two before running it back in through the lid?

This should lower the temperature a few degrees and you can either have it on a timer so that it runs during the day/night and shorten/lengthen the tube to control how low the temperature goes.

Just a thought, because filtering that all the time would suck...

[Bacon46]

I have considered cooling it, but since I am only going to run it for another week or two I think I’ll just let it run hot and see what affect, if any, the higher temperatures have on the cells productivity. I’ll have to filter graphite until I can come up with a better anode material. It is kind of a pain in the ass.

Four materials I have never heard discussed for chlorate cell anodes are Gold, Silver, Bismuth or Tin. I have plenty of .999 Silver and Tin and .95 Bismuth. I would have to plate something in Gold. There are probably good reasons why I haven’t seen them mentioned but I don’t know what they are.

Any thoughts?

[Alexires]

I would be inclined the believe that the silver and the tin form their respective chlorides and the bismuth forms bismuth oxide, but that is just a wild guess.

Anyone with more of an idea, please correct me.

The best anode I have heard of is a Platinum/Iridium anode. You seem to be able to get your hands on some expensive metals, so if you can easily get that, give it a go.

[totenkov]

Having some problems with my sodium chlorate!

I ran my cell for 9 days, each day adding .5% solution of HCl and NaCl until it would no longer dissolve. The power source was 900Ma at about 4V. The electrolyte slowly turned a yellowy urine color over the course of the nine days it was running. The cell was run outside and the temp was kept in the range of 5-10 degrees celcius. I used small graphite electrodes and about 1 liter of distilled water.

At the end I filtered the solution until I got a yellowy liquid. I boiled it down from about 800 mills (starting was 1000 but the other 200 must have evaporated off) An when it got down to about 400 all the sodium chlorate precipitated. I was very surprised at the size of the yield, a total of about 250 grams, pretty good for the first run!

Now, what this was all leading up to :) :

I mixed 2 parts "sodium chlorate" with 650 mesh Al powder and did a flame test. Nothing happened. I chucked the matches and tried the acetylene torch. Nothing happened. At this point I am getting a bit annoyed ;) And chucked the remaining NaClO3 into my oxidizer storage and came down to write this post.

Anyone know what happened? Did I make something other than sodium chlorate? I know NaClO3 is very hygroscopic so I left it in the presence of CaCl2 for a week and its nice and dry, anyone spot problems?

[nbk2000]

Try it with some french fries to make sure it's not salt. ;)

[ChippedHammer]

Mix it with a small amount of sugar and try that.

[nbk2000]

Sugar on french fries?! :eek: ;)

[Bacon46]

Having some problems with my sodium chlorate!

Here is a link to the instructions I used to set up my first chlorate cell. It's a good place to start.

Wouters Practical Pyrotechnics (http://www.wfvisser.dds.nl/EN/kclox_EN.html)

[Charles Owlen Picket]

Having some problems with my sodium chlorate!
The power source was 900Ma at about 4V. anyone spot problems?


Current is the issue, IMO -as you describe it; "400Ma" is simply too low a current element to achieve the results you want. Notice in past posts the discussion centers on rather HIGH current values. No big deal; you simply need to understand the electrolytic process, which generally requires high current.

.....That's why you read the discussion of automobile batteries and arc welders utilized to set up the process: the need for high current. I'd bet if you attempted it again and used a power source of high current, you'd get outstanding results.

[totenkov]

I did notice. I thought using a neon sign transformer or something with high voltage would be fesable but then realized it amps we want, not high voltage. So what your say is I didn't get "complete" electrolysis? And my end product was just salt?

I don't think I want to taste it.:)

Oh well, I will see what I can do for higher amperage. I don't want to run my arc welder for days on end (even though its older than me and has a 100% duty cycle)

[ChippedHammer]

Sugar on french fries?! :eek: ;)

What you haven't tried sodium chloride, sodium chlorate and sugar on chips?

I swear its delicious ;)

[totenkov]

I dunno, even if you have the munchies, its still not a good idea to go digging around in your chems for food :D

[Bacon46]

I thought I would post the results of my last two chlorate cells for comparison. There where significant differences in the cells but very little difference in the outcome.

A small improvment is better no improvment.:D

8 Liter Chlorate Cell Run in September of 2007

Specifications


Starting electrolyte: 3.2kg NaCl in 8 liters of H2O
Run time: 30 days * 24hrs per day = 720 hours
Maintenance Down Time: 20hrs
Net Run Time: 700 hours
Average Current Draw ~12.0 amps (700 * 12.0 = 8400Ah)
Average Operating Temperature: 54oC
24g (3g/l) K2Cl2O7 was added to increase current efficiency
Anode deterioration ~ 3g per day
Cell was run covered for half of the run to slow evaporation and maintain higher operating temperatures

Production & Efficiency

Theoretical Production at 100% Efficiency
0.66g NaClO3 per Ah (0.66g * 8400Ah = 5.54kg NaClO3 + 970g NaCl)

Actual Production ~35% Efficiency


1.95kg NaClO3 / 8400Ah ~ 0.23g NaClO3 per Ah
2.26kg KClO3 / 8400Ah ~ 0.26g KClO3 per Ah net after reacting with KCl, recrystallization and rinsing.


15 Liter Chlorate Cell Run in January of 2007

Specifications


Starting electrolyte: 5.8kg NaCl in 15.2 liters of H2O
Average Operating Temperature ~ 32oC
Run time: 28 days * 24hrs per day = 672 hours
Maintenance Down Time: 2hrs
Net Run Time: 670 hours
Average Current Draw: ~10 amps (10 * 670 = 6700Ah)
Anode deterioration: Negligible
The cell was run uncovered

Production & Efficiency

Theoretical Production at 100% Efficiency
0.66g NaClO3 per Ah (0.66g * 6700Ah = 4.4kg NaClO3 + 3.48kg NaCl) See notes

Actual Production ~34% Efficiency

1.55kg NaClO3 / 6700Ah = 0.23g NaClO3 per Ah

1.81kg KClO3 / 6700Ah = 0.27g KClO3 per Ah net after reacting with KCl, recrystallization and rinsing.


Notes

The slight increase in efficiency of the 8 liter cell can most likely be attributed to the increased operating temperature and the addition of the K2Cl2O7. I believe a greater increase in production would have been realized had I started out with a cover on the cell the K2Cl2O7 in the electrolyte. I am going to start another 8 liter cell in the next day or so with those things in place and compare the two.

There was no amp meter in place during the operation of the 15 liter cell. The numbers used to calculate Ah for that cell are estimates based on what I learned while operating the 8 liter cell with an amp meter installed. You may have also noticed the excessive amount of NaCl remaining in the electrolyte of this cell at the end of the run. With my existing power supply and a desired run time of 30 days a cell capacity any greater than 8 liters is a waste of time.:o

I will have to look into it, but I may be able to run two 8 liter cells with this power supply by using the other 6VDC leg of the transformer. It will depend on the current available at that leg and whether using one leg will affect the current output of the other.

[russoc4]

What is the purpose of the HCl? I thought that the electrolysis of NaCl in H2O was sufficient enough to create Cl2 and NaOH, which in solution forms NaClO (hypochlorite) at low temperature, but NaClO3 (chlorate) at high temperature? Couldn't you also just heat sodium hypochlorite to get sodium chlorate?

[Bacon46]

What is the purpose of the HCl?

At low pH the cell generates chlorine gas that escapes out of the cell. This causes the pH to rise. As the pH rises the ease with which chlorine can escape decreases until it stabilizes at a pH of around 8 or 9. At this pH practically all Chlorate is made by electricity at a maximum possible current efficiency of 66.7%. Reaction of intermediates in the bulk of the solution is drastically reduced.

A pH of 6.8 is considered optimum. Maintaining this:

Increases current efficiency

Extends graphite anode life (In my case)

Facilitates bulk reaction of intermediates.

Although I have managed to control the pH with some success, I have never achieved anything near 66.7% efficiency. The best I have done is ~36%. As I understand it this is not uncommon. For this reason many people feel attempting to control the pH in a "Back Yard" chlorate cell is a waste of time.

I disagree. Why even try if you’re not going to do everything you can to achieve the best possible result.


Couldn't you also just heat sodium hypochlorite to get sodium chlorate?

Yes. I have never done it, but as I understand it achieving yields similar to those achieved with a chlorate cell using this method is much more laborious.

Now I have a question.

On the past two chlorate cells that I have run I have used copper pipe as a cathode and as a conductor to carry current to the graphite anodes. It has never been a problem. I did the same thing on the cell I am currently running. The difference this time is that the cell is completely enclosed. It is a 19 liter plastic bucket with the lid on and holes drilled through the side of it for the copper pipe to pass through. The electrical connections are made outside the bucket. The anodes hang from one pipe into the electrolyte. The cathode is a copper tee with one leg submerged.

The cell has been running for seventeen days. For twelve of those days there was no lid on the bucket. As the ambient temperature dropped I insulated the bucket and added the lid to keep the electrolyte temperature between 70oand 80oC. It has run for one week in this configuration.

Today when I went out to check on the cell I found that large sections of both the cathode and the conductor for the anode had dissolved. The cathode lost approximately 4cm just above the water line. The pipe that the anodes hung from lost 10cm from the center. Both anodes fell into the electrolyte. Fortunately neither made contact with the cathode. They did however move close enough together to cause the electrolyte temperature to rise above 100oC causing the cell to boil over at some point.

I think it’s safe to say the rapid corrosion was caused by the slightly acidic sodium hypochlorite / chlorine sauna they were suspended in. My concern is the CuCl2 that has been added to the electrolyte. It appears that a good deal of the dissolved copper was deposited on the cathode (http://img211.imageshack.us/img211/3296/corrodedcathodeqg7.jpg) just above the water line but I would estimate at least 10g of CuCl2 was added to the electrolyte.

My question is; is there cause for concern, and if so does anyone have a solution to the problem?

[tranquillity]

Bacon: You could try adding NaOH to precipitate Cu(OH)2 which could then be filtered. Once all the copper is removed re-acidify with HCl. I couldn't tell you if that would affect any of the intended products but i don't see why it would.

[Bacon46]

Bacon: You could try adding NaOH to precipitate Cu(OH)2 which could then be filtered.

Thanks Tranquillity

I use NaOH to adjust the pH of the electrolyte to between 8 and 9 prior to processing. If that will precipitate Cu(OH)2 I don't see any reason why I should be concerned.

[penguin6636]

How do you guys clean all the crap from the electrodes? Do you just let it settle and decant most liquid or filter the whole thing?

[chillardbee]

I must throw my two bits into this thread as I have had trial and error and success at making chlorates.

When I first started my cell I used a sodium chloride saturated solution and using many different type of electrodes and all seemed to errode. I tried steel, lead, titanium drill bits and almost everything else and in different combinations also. I finally bought some carbon electrodes and even though they will erode in time I found it easier to remove the solid particulate from their erosion.

Now, a point to ponder here. NaCl dissolves at 35.9 gm/100cm3 and NaClO3 at 95.9 gm/100cm3 of water with a temperature of 20c. After the cell has run its course you would have to reduce the solution considerably to condense the crystals out of the solution or even evaporate the water off all together or add KCl in to the solution to precipitate KClO3. NaClO3 It is quit hygroscopic.

Knowing that KClO3 is by far more a desired product I used KCl I bought as NoSalt and made a saturated solution. I then filtered off the crude that was in it and started my cell. KCl dissolves at 34.2 gm/100cm3 and KClO3 at 7gm/100cm3 of water with a temperature of 20c, that’s a very big difference and more so with Perchlorates.

My cell for this run was run for 3 days with carbon electrodes and 1 liter of solution with 10amps from a 12 volt battery charger. Much to my surprise there was a mother load of crystals already precipitated from the solution after filtering the still warm solution I cooled it to near freezing point and got even more crystals. I ran the solution through the cell 2 more times and I was still getting crystals. I was thoroughly over joyed.

There is a website that you can visit, though I’m sure most of you have it favorited, that will allow you to calculate the cell efficiency, it is http://www.vk2zay.net/calculators/?body=chlorates.php and the link for this is also found on Wouter Visser’s site at http://www.wfvisser.dds.nl/EN/kclox_EN.html and one more to check out is http://www.vk2zay.net/article.php/63 . I believe that anyone who’s going to chlorate or perchlorate should read this stuff first, It’s very informative.

I hope this is of some help to somebody, thank you.

[Bacon46]

I agree chillardbee

I used the information from Wouter’s Practical Pyrotechnics to set up my first cell. The information provided there is very useful for the beginner but it leans more toward producing NaClO3 and reacting it with KCl to produce KClO3. Their reasoning behind it is that NaClO3 dissolves easier in water and is therefore easier to filter.

When I set up the cell I am currently running, I decided to recycle the electrolyte that was left over after processing the the contents of my previous cell. This electrolyte contained a significant amount of KCl that was not consumed in the Metathesis reaction but I figured I would try it.

My results were similar to yours. I was two weeks into the run and I was doing routine maintenance. I realized there quite a bit of KClO3 had precipitated and was sitting at the bottom of the cell. I removed some of it and processed it. Processing the KClO3 from KCl electrolyte was much easier than going through the reaction process with NaClO3. It has to be filtered hot but that is no problem. The cell with the KCl electrolyte still has a couple of weeks to run so I don’t have the final numbers yet but the efficiency seems to be better as well. The cells I run are usually 8 liters and run for around a month.

I am writing instructions with images that show my take on this process and should post them in three weeks or so.

The topic of this thread is actually on NaClO3 electrolysis. This is so similar to KClO3 electrolysis if there are no objections from the Mods I figure we should just keep using it even if we are straying off topic.

[Thermiteisfun]

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/leaddiox/fig1.gif
With a "Graphite Substrate Lead Dioxide (GSLD) Anode"
Just thought I should share this...

[ChippedHammer]

Cool graph!

I'm still looking for a decent anode, hoping to get some nitric acid so I can try my hand at making a LD anode.

[chillardbee]

There is so much more that can be said on this subject and even though I did throw in my two bits worth I’m still learning about the subject on how to make chlorates and per chlorates.

I was asked how I filter off the Carbon sediment. This is a bit embarrassing, but I had to dissolve the chlorate in a lot of water and let the sediment settle over 24 hours then carefully pour the liquid of the sediment, a process that’s known as “raking” in wine making terms. Afterwards it is clean enough to filter through towel or paper coffee filters. In either case, if you notice a bleaching action in the filter, you will have hypochlorite in the solution, which is bad, so be warned. I boiled my filtrate to effectively destroy the hypochlorite’s and evaporate the water to reclaim the chlorate and this process is also time consuming.

I agree with Bacon as well but I never did try the sodium chloride in my working cell. I think if I did I would have had better results precipitating potassium chlorate afterwards.

I should mention also that after running my cell there was nothing left of my electrodes so this stint at making chlorates was really just a rushed thing to see if I could succeed. What I really need to do is get either platinum electrodes which I can’t seem to justify the cost for, or lead dioxide. I’m going to try an experiment here soon with a lead dioxide source and if it works I will most certainly post the results.

Now I know this thread is on sodium chlorate production but feel strongly that sodium chlorate is an intermediate for the production of sodium per chlorate, which is an intermediate again for the production of potassium per chlorate. I write this because of the sever sensitivity of chlorates. It is true that chlorate it is more reactive in compositions but for its sensitive nature I can hardly recommend it. I have made compositions with it and whilst I did, I though I could hear the devil confirming reservation on my behalf, because truly, I thought or felt like I was going to be blown to hell while making my devices. After I lit off my devices that were blasting holes in 1/8 think steel I said to my myself “imagine if it were to go off in your hand by accident because off it’s sensitivity”. No thank you, I think I’ll stick with per chlorates. I prefer to be a coward with all his limbs in tacked.

[Thermiteisfun]

For my electrodes I just took two carpenters pencils and burnt the pine off for two fairly large graphite bars...by the way, hold it with gloves because graphite seems to be a good heat conductor :rolleyes:

[ChippedHammer]

I found a person who imports platinum plated crap from India and he may be able to get commercial lead dioxide anodes for about $50. He currently has MMO anodes which are perfect for chlorate production (400mA sq cm easy, no filtering needed)

He is looking into it for me :)

[gliper]

''There is something about using/converting sodium metaborate for use in hydrogen fuel cells but I couldn't find much more out''

That somthing is that it reacts with hydrides to liberate H2.

Has anyone separated metaborate yet? Does anyone know why its not an oxidiser? Na2B2O4 realy looks like one.

[ETCS (Ret)]

Carbon/Graphite rods work well for the Anodes (Chlorine liberating electrodes) in the cell and will have a long life if the current through the cell is kept small.

The cathodes, the Hydrogen liberating electrodes, are usually steel (I use large steel nails.) The steel cathodes have been very durable when in constant use. If left to sit in the cell during periods of non-use they will tend to rust.

If you intend to not operate your cell for a length of time, remove the electrodes, rinse them thoroughly, then dry them with paper towel.

The secret to good life and efficiency with carbon anodes is to run them at low current levels to produce only moderate to no warming of the electrolyte, and to have the anodes and cathodes very close together (1/8 to 1/4 inch) to assure good mixing of the bubbles and the reactive chemicals they produce.

If you are using rod electrodes it is very beneficial to arrange them horizontally near the bottom of the cell with the Cathodes (Hydrogen) beneath the Anodes (Chlorine.) This will create a wide stream of bubbles that mix well as they work their way to the top of the solution, and that will create a nice convection current within the cell to keep the electrolyte in constant circulation.

The lower current levels, 1 to 5 amperes, will necessitate longer operation to get the good yield, so patience is required, but in time you will see the Sodium Chlorate crystals settlling to the bottom of the cell.

[Charles Owlen Picket]

I'm going to be giving something like this a try and I wondered if the graphite makes a mess.....? If something common may be substituted and it's performance level....? I see (from a search) that many people have no issue with copper as a cathode so why not stainless steel as an anode? I am new to this so I would appreciate some direction and source citation, etc (what I have found was the same material as many; like Wouter's pages)...Thanks!

[tranquillity]

In my experience with battery electrodes (carbon) it makes a big mess. My whole solution turned black as the electrodes corroded and needed to be filtered before converting to KClO3.

Any metal anode (except platinum of course) would corrode very fast. A cathode protects the electrode from oxidation whereas an anode encourages oxidation. This combined with the hot chlorine that is liberated at the anode makes common metal anodes useless. I am no expert on the subject but for an anode you need platinum or a conductive metal oxide such as lead dioxide.

This is an excellent website discussing all aspects of (per)chlorate production: http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/chlorate.html

[ETCS (Ret)]

The Cape Canaveral website link you've provided is a good one.

It is true that battery carbons have a tendency to erode more quickly than the harder pressed graphite rods. The battery carbons are rather loosely pressed and are quite porous.

However, when the battery carbons are used at a current level of 200 Milliamperes per carbon rod ( assuming you're using an array of 4 to 6 carbon rods ) then the rate of erosion caused by the liberation of Chlorine is greatly reduced. Try to adjust the total current to the cell to a level that will only produce a cool to slightly warm solution.

It is best to have a power supply, preferably a switching supply, that will permit adjustment of voltage, and hence current, in order to adjust it to the characteristics of the cell.

In a small half gallon cell it has been possible to obtain Sodium Chlorate in a nearly clear solution at a low current level. The trade-off is that it takes about two weeks or more of continuous operation to get a good yield.

When running a cell hot to obtain a yield quickly the carbon rods will deteriorate rapidly and leave a messy solution.

[jpsmith123]

Pool chlorinator MMO anodes may be a good off-the-shelf solution for chlorate production although they can be fairly expensive.

Finding suitable anode materials for perchlorate production is a vexing problem. AFAIK, only two types of anode materials have had commercial success: platinum and lead dioxide. Of course platinum is prohibitively expensive, and PbO2 is troublesome to plate on correctly and its precursosrs are toxic.

Unless you are using a chunk of platinum, the titanium substrate can be hard to find and expensive (depending on where you live) and it can be a PITA to prepare. If you're going to plate it with PbO2 you need to first apply an intermediate layer of another conductive oxide or platinum, basically to prevent the passivation of the Ti (formation of a TiO2 layer).

I think that anybody that comes up with a cheap and easy to make perchlorate anode would be wealthy.

[Charles Owlen Picket]

Within the basics of chlorate production, what would be the result if a stainless steel anode were utilized? Why the emphasis on super conductivity?

[tranquillity]

Stainless steel would corrode in preference to the oxidation chlorine. You would end up with a solution of iron, chromium, sodium and chloride, with perhaps a small amount of hypochorite.

Stainless steel can be used as a cathode as the impressed current provides excess electrons in the electrode, these protect the cathode from corrosion. In an anode there are less electrons than there should be which weakens it to oxidation. I expect if you were to leave a SS rod in a chlorate cell without any electrical polarity it would corrode too but i might be wrong about that.

You need your anode (and cathode) to be very conductive in order to push enough current through solution as it takes a surprising amount of electricity to convert chloride to chlorate. Here is a calculator so you can get an idea of the time required. http://www.vk2zay.net/calculators/chlorates.php

[jpsmith123]

Several reactions are possible at the anode...you can liberate oxygen or you can liberate chlorine (which is what you want). The stainless steel will primarily liberate oxygen and will corrode. A good anode will not only resist "wear", but it will be "catalytic" in the sense that it will preferentially liberate chlorine; IOW it will have a relatively "high oxygen overpotential" and a "low chlorine overpotential" or something like that.

The "conductivity" of the electrodes per se is not a big issue unless it's really bad.

[ChippedHammer]

Don't bother with carbon for chlorate production, get a MMO anode. Zero corrosion and the thing will last for years. There is a seller on eBay who is selling commercial chlorate anodes from India. They work very well :)

[ETCS (Ret)]

The commercial chlorate cells are massive arrays of paralleled Graphite and Steel sheet electrodes that are closely spaced. The voltage applied to the cells is 3.0 to 3.5 volts to achieve a current density of 60 milliamperes or less for each square inch of total graphite plate surface.

The production of Chlorate is a slow process, some of it occuring in the cells as the electrolyte solution is pumped through, and most of it occuring in the rundown tanks as the solution cools and the crystals form.

Cells which use the newer Dimensionally Stable Anodes will operate at a higher current density, as in these there is not the graphite erosion problem.

There is a tendency for those of us who desire to make our own in small quantites to grossly overdrive our cells with a great excess of electrical energy which erodes carbon/graphite anodes very quickly.

Try to operate your cells within the same parameters as the commercial graphite anode cells:

3.0 to 3.5 volts per cell,

less than 60 milliamperes of current for each square inch of anode surface area,

and your carbon/graphite anodes will have a long life. The electrolyte solutions will remain nearly clear throughout the process. Needless to say, at these lowered levels of current flow the process will take much longer, but Chlorate will form no matter what the cell temperature, providing it is in the range of "room temperature;" 70 degrees Fahrenheit or 22 degrees Celsius, or thereabouts.

[Bacon46]

Al-doped ZnO as a Potential Coating for Chlorate Anodes and Method of Application.

I was doing some research on conductive oxides with the hope of finding a potential coating for dimensionally stable chlorate anodes other than electroplating with lead dioxide. The Combustion Chemical Vapor Decomposition (CCVD) process seems feasible at the amateur level. The process was devised for applying transparent conductive coatings on glass for use in solar cells.

I used only the information relevant to the process of CCVD itself and left out the information pertaining primarily to photovoltaic cells. I have attached the paper in its entirety for those who are interested.

The following information was taken from.
TRANSPARENT CONDUCTING ZNO:AL FILMS VIA CCVD FOR AMORPHOUS SILICON SOLAR CELLS
Z. Zhao, M. Vinson, T. Neumuller, J.E. McEntyre, F. Fortunato, and A.T. Hunt G. Ganguly

Al-doped ZnO films were produced by a novel deposition method, Combustion Chemical Vapor Deposition (CCVD) Their structural and electro optical properties will be presented as a function of deposition and annealing conditions. Tandem a-Si solar cells have been made on the ZnO:Al films.

ABSTRACT

Highly transparent conducting ZnO:Al films have been fabricated using the Combustion Chemical Vapor Deposition (CCVD) process. CCVD is an open atmosphere process and uses inexpensive precursors to produce thin films, which enables large-area deposition with high throughput at low cost. Structural, electrical, and optical properties of the films were characterized. Synthesized ZnO:Al films showed polycrystalline structure with a (002) textured orientation. Electro-optical and morphological properties were found to depend on process parameters such as solution concentration and flow rate, doping concentration, and annealing conditions.


EXPERIMENTAL DETAILS

The schematic of the CCVD process is depicted in Fig. 1. In this process, precursors, which are the metal-bearing chemicals, are dissolved in a solution which typically is a combustible fuel. This solution is atomized to form micron size droplets by means of MCT's proprietary Nanomiser TM device. These droplets are then carried by an oxygen stream to the flame where they are combusted. A substrate is coated by simply drawing it in front of the flame. The heat from the flame provides the energy required to vaporize the droplets and for the precursors to react and deposit on the substrates.

This continuous, open-air deposition process holds several advantages over traditional thin film techniques, such as CVD and physical vapor deposition. The CCVD process does not require highly specialized and expensive equipment (e.g. vacuum chamber, reaction furnace), allows for continuous production-line manufacturing, and eliminates the use of expensive, environmentally harmful (e.g. chlorine or fluorine) or toxic precursors. In summary,
CCVD offers the following capabilities for depositing TCO films:

• Uses inexpensive precursors
• Provides high degree of composition control
• Suitable for continuous production
• Deposits on a wide choice of substrates
• Precise control of coverage area
• Outstanding microstructure control
• Accelerated development cycle
• Environmentally friendly

In the present study, two kinds of glass substrates, borosilicate and soda lime glasses, were utilized. Inorganic precursors of Zn and Al were used for ZnO:Al deposition due to their low cost and high stability. Al doping concentration can be easily adjusted by varying the molar ratio of Al and Zn precursors in solution. The CCVD process parameters were investigated in-depth to achieve ZnO films with desired properties.

Figure One
http://img84.imageshack.us/img84/5690/ccvdimagenx9.jpg


I have atomized Al and Zn. I have a tank of oxygen and a flow meter. I don’t happen to have a “Nanomizer” but I do have a commercial, high pressure airless paint sprayer designed for atomizing latex or solvent based paint. It will turn some pretty thick material into a pretty fine mist. The droplet size is variable by increasing or decreasing the size of the nozzle and viscosity of the material.

I have no idea whether this coating would be suitable for chlorate production and am looking for insight. If not this coating, then maybe this process with different precursors could work.
What do think?

[jpsmith123]

Probably the best thing for chlorate production is to just buy a generic, low-end pool chlorinator cell...or at least a replacement anode from such a cell.

Moreover, it might be possible to use the chlorinator cell anode out-of-the-box as a substrate for a coating of PbO2 (IIRC there's a Diamond-Shamrock patent that implies this)...thereby enabling you to make perchlorate.

There are a few long, active, on-going threads about this and related topics over at the Science Madness board.

For example, one thing many of us spent time on, myself included, was cobalt oxide. Based on a few promising-looking patents and a paper or two, I thought for sure it could be made to work, at least for chlorate production. As it turned out, anodic electrodeposition of the oxide didn't really work at all (it wouldn't stick very well to graphite, platinum, or titanium), and when pyrolytically deposited, i.e., baked on, it was more adherent, but it just didn't last very long as an anode coating (failed after a few days).

It seems that the process of trying to sort out what works and what doesn't, is strictly a trial and error process. And, given all the variables involved, it's a very tedious, frustrating, completely thankless task.

After working at it for many months, Dann2 (on the SM board) may finally have made his first reliable PbO2 anode. He just started testing it a few days ago, so we won't know for a while yet how it'll hold up (although I would say it looks promising so far).

I'm preparing to try to electrodeposit a diamond-like coating on a few different substrates. Based on what I've read, DLC may be the ideal anode coating material. With all the hassle of repeated dipping and baking and the messy, toxic precursors involved, etc., I'm not very much interested in trying to do anything similar to what Dann2 has done, so I'm looking at DLC as a possible alternative.

[Bacon46]

Probably the best thing for chlorate production is to just buy a generic, low-end pool chlorinator cell...or at least a replacement anode from such a cell..

If you’re going to buy an anode the MMO coated Ti ones Chipped Hammer mentions above are probably a better alternative than a pool anode as they are designed for the higher concentrations of NaCl/NaClO3 and the lower pH of a chlorate cell. I have never priced a pool anode but the MMO coated Ti ones are reasonably priced as well. I ordered both an anode and cathode this morning.

Whether I can purchase an anode or not, I would still like to find a relatively simple way to manufacture my own and the CCVD process seems to me (a clueless pyrotech) to have potential.


It seems that the process of trying to sort out what works and what doesn't, is strictly a trial and error process. And, given all the variables involved, it's a very tedious, frustrating, completely thankless task.

Except for the completely thankless part that's what scientific experimentation is and why this forum exsists!

[Charles Owlen Picket]

Probably the best thing for chlorate production is to just buy a generic, low-end pool chlorinator cell...or at least a replacement anode from such a cell.

Are these available in standard "pool supply outlets", etc? What's the material & design?

-=-=-=-=-=-=-=-
Damn fine post there Bacon. However, is the material available commercially? I didn't get a chance to see the PDF as it's "pending" as I write this - so where does it leave us? What were the "nuts & bolts?" Where did you hunt up the materials? Have you gotten this unit to produce & if so, what were the results?

[jpsmith123]

If you’re going to buy an anode the MMO coated Ti ones Chipped Hammer mentions above are probably a better alternative than a pool anode as they are designed for the higher concentrations of NaCl/NaClO3 and the lower pH of a chlorate cell.

But pool chlorinators are MMO coated Ti anodes; or are you suggesting that the ones mentioned by "Chipped Hammer" are somehow better than the ones used in pools? AFAIK, all commercial MMO anodes are based on Beer's patents and are thus all very similar. There are some papers suggesting that MMO anodes using a mixture of IrO2 and RuO2 (with TiO2 of course) will last longer than straight RuO2 for chlorate production, but I don't know of anything beyond that. If you have specific information to the contrary, please cite it.


Whether I can purchase an anode or not, I would still like to find a relatively simple way to manufacture my own and the CCVD process seems to me (a clueless pyrotech) to have potential.

Hey knock your socks off. Have fun. Maybe you'll come up with something. But for somebody who doesn't want to spend what may amount to literally hundres of hours on research, spend money on various precursors and other raw materials, equipment and hardware, etc., well, if you just want to make chlorate, buying a pool chlorinator cell or anode (or other MMO anode) is the way to go.

Except for the completely thankless part that's what scientific experimentation is and why this forum exsists!

Well sure, up to a point. If you've studied the available literature first and looked at the dozens of related patents, and looked at all the relevant discussions at the SM board, and after doing that you have some specific ideas that you want to try, then by all means, go ahead. Yes, that would likely be interesting, instructive and rewarding.

But if you jump in without some fairly specific ideas of what you want to do, not realizing what's already been tried, and are not aware or appreciative of the fact that many companies with lots of talented industrial chemists at their disposal have spent lots of time and money trying to come up with a better/cheaper anode...to no avail...you're setting yourself up for disappointment.

[Bacon46]

Not all MMO coatings are the same. Tests performed by Corrpro Companies, a corrosion control company based in Ohio, suggest that a Ti/Iridium oxide (IrO2) anode in sulfuric acid (H2SO4) at a current density of 30 mA/cm3, will run approximately 3,000 days, whereas a Ti/Ruthenium oxide (RuO2) anode under the same conditions may only run 200 days. Then you have the variables associated with the application of the coatings and proper preparation of the substrates.

Most swimming pool chlorinator anodes are designed to operate intermittently for approximately 5 years at a current density of 30 mA/cm3. They are designed to operate in water containing 2.5 grams/liter NaCl, with pH close to 7.0, and temperatures ranging from 15 to 20oC.

Chlorate electrolyte contains approximately 365 grams/liter NaCl. I try to operate my graphite anode cells at a current density closer to10 mA/cm3with the pH between 5.5 and 6.0 and temperature between 70o and 80oC. Conditions much harsher than swimming pool water even at the lower current density.

There are three reasons I went with the anodes mentioned by ChippedHammer.


Pool chlorinator anodes are not designed for use in chlorate cells and it doesn’t seem likely that the profit minded company’s manufacturing these anodes are going to build them any stronger than they have to.


The cost of pool chlorinator anodes is prohibitive.


I just feel more comfortable purchasing an anode tested and proven to work for the intended purpose by a member of this forum.


I am not saying pool chlorinator anodes won’t work. If you have successfully used a pool chlorinator anode and know where I can purchase one for $35.00 or less please PM me with the specifics. In my attempts at finding retail anodes for pool chlorinators all I was coming up with was replacement cartridges for around $250.00. Hence reason number two.

"But if you jump in without some fairly specific ideas of what you want to do, not realizing what's already been tried, and are not aware or appreciative of the fact that many companies with lots of talented industrial chemists at their disposal have spent lots of time and money trying to come up with a better/cheaper anode...to no avail...you're setting yourself up for disappointment."

I agree, to a point. :D

I think I outlined some “fairly specific” ideas as to what I want to accomplish in my post on CCVD. My reason for posting it prior to starting any work on the project was an effort at getting some constructive input from forum members with more knowledge than I on the subject; which is probably 80% of the active members.

The “companies with lots of talented industrial chemists at their disposal have spent lots of time and money trying to come up with a better/cheaper anode” are researching ways to produce chlorates on an industrial scale. There could be, and probably are, unpublished, un-patented experiments considered “failures” that would work fine for the backyard chemist.

I already have everything I need to give this a try, equipment (improvised) and precursors. Mechanically I think I can pull it off, but if I am just pissing in the wind and there is someone out there that can tell me why I have little to no chance of success it would save me a lot of grief and I will pursue other experiments on my seemingly endless list.

On the other hand; if someone feels there is a chance something could come of it, maybe they could provide me with some insight on how best to proceed.

If I get no feedback leading me one way or the other I will proceed with it on my own and hope for the best. If I fail all of the equipment will go back to being used for its original intended purpose and I will undoubtedly have learned something in the process.

[jpsmith123]

Not all MMO coatings are the same.

Well of course they're not all exactly the same. But for purposes of making chlorate (especially with a high concentration of chloride ion), any pool chlorinator should make chlorate efficiently and reliably.

Tests performed by Corrpro Companies, a corrosion control company based in Ohio, suggest that a Ti/Iridium oxide (IrO2) anode in sulfuric acid (H2SO4) at a current density of 30 mA/cm3, will run approximately 3,000 days, whereas a Ti/Ruthenium oxide (RuO2) anode under the same conditions may only run 200 days.

To the extent that's true, it's irrelevant, since you won't be running in H2SO4. PbO2 won't last in H2SO4 either, for example. (BTW can you point me to that study or give the abstract or something?)

Then you have the variables associated with the application of the coatings and proper preparation of the substrates.

Well I suppose there are always "variables"; hopefully, regardless of where you get your anode, the manufacturer has some quality control efforts going on. If you try to talk to manufacturers, as I have, you'll find that many of them won't go into detail on the coating. They'll ask you what your application is, and they'll apply their proprietary tweaks and ship it to you.

Most swimming pool chlorinator anodes are designed to operate intermittently for approximately 5 years at a current density of 30 mA/cm3. They are designed to operate in water containing 2.5 grams/liter NaCl, with pH close to 7.0, and temperatures ranging from 15 to 20oC.

Well my 20 amp cell runs somewhere around 75 mA/cm^2 (manufacturer's design spec)...not that it really matters that much within reason. It seems to me the "design" of these things is fairly well fixed. Other than a small variation of composition and a small variation of loading (i.e., grams of noble metal oxide per square meter), I don't think there's an awful lot of inherent design flexibility. Mainly what they do I think is vary the surface area and the current spec to get the lifetime they're shooting for, for any given chlorine output.

Chlorate electrolyte contains approximately 365 grams/liter NaCl. I try to operate my graphite anode cells at a current density closer to10 mA/cm3with the pH between 5.5 and 6.0 and temperature between 70o and 80oC. Conditions much harsher than swimming pool water even at the lower current density.

How would that be more harsh? I would say that running at a low chloride concentration, like a pool chlorinator normally would, where you'd expect to make more oxygen, would be harder on any anode than running at a high chloride concentration. In any case, a typical industrial chlorate cell may run at 200 mA/cm^2, pH 6 to 7, temp 60 to 80 degrees C. So a pool chlorinator should be expected to run good in a chlorate cell.

There are three reasons I went with the anodes mentioned by ChippedHammer.

Pool chlorinator anodes are not designed for use in chlorate cells and

Sure they are. They're RuO2/TiO2 or RuO2/IrO2/TiO2 over a titanium substrate. Same exact thing used in the Chlorate industry.

it doesn’t seem likely that the profit minded company’s manufacturing these anodes are going to build them any stronger than they have to.

I really don't know what you mean by "strength" here. Since these things seem to be run (by the manufacturer's specs) at a very conservative current density, and since, IIRC, the failure mechanism is by slow passivation of the Ti substrate, not by "electrochemical wear" of the coating; therefore, unless you're going to operate at an extreme pH, extreme temperature, or extreme current density, the thing should last a damn long time whether in a pool or chlorate cell.

The cost of pool chlorinator anodes is prohibitive.

Cost on what basis? Cost per lb of product? Cost per unit area of anode surface?


I just feel more comfortable purchasing an anode tested and proven to work for the intended purpose by a member of this forum.

Well, I'm a member of this forum and I've made chlorate with a pool chlorinator :).

[Bacon46]

There is nothing in any post you have made in this thread that indicated you had actually used one until your last post and that’s just:

Well, I'm a member of this forum and I've made chlorate with a pool chlorinator :).

Had you mentioned that back in post 127 along with a line or two on the anodes performance, where you purchased it and how much you paid for it we wouldn't have wasted our time and the forums space with every post since then.:mad:

I don’t moderate this section but I will ask Mega if it would be appropriate to delete every post after 127.

I apologize for allowing myself to get caught up in that exchange and wasting forum space and readers time.

[jpsmith123]

There is nothing in any post you have made in this thread that indicated you had actually used one until your last post...

LOL! Nor did I say that I never used one, for that matter. Although I've had the cell for quite a while (two cells actually) it's only been rather recently that I've used it, and, being that I haven't yet made hundreds of pounds of chlorate with it (as I have no good place to work right now), I can't speak from personal experience as to how long it will ultimately last, etc.


Had you mentioned that back in post 127 along with a line or two on the anodes performance, where you purchased it and how much you paid for it we wouldn't have wasted our time and the forums space with every post since then.:mad:


The discussion was rather more about "theory", no? Your position appeared to be that a MMO pool chlorinator wasn't "designed" to make chlorate. Had you stated a belief that it simply won't make chlorate, then I could've refuted you based on personal experience.

Another point you raised is that there are "differences" between MMO coatings. Well nothing in my personal experience allows me to claim that a cell you would get from "Direct Pool Supplies" will perform exactly the same as one you get from "Watermaid" for example. So once again my personal experience isn't very relevant in that regard. Do you follow?


I don’t moderate this section but I will ask Mega to delete every post after 127.

I think you're being a little silly.

Edit:

I'm going to try to attach a picture of the cell I made from a pool chlorinator. What's nice about the pool chlorinator is that it's all titanium construction. The anode and cathode plates are held together by plastic bands (they're separated by about 8mm). I basically just took a 1 gallon PET jar from Wal-Mart and drilled holes in the polypropylene lid for the two electrodes and vent tube. The studs are also titanium and they're sealed with viton o-rings and titanium washers.

[ChippedHammer]

I looked into getting a pool chlorinator and they were fairly expensive ($150 + shipping) for something that was fairly unknown (I cant ask the store if it will make chlorate well can I?)

Ended up with a anode designed for what I had in mind and it only cost $40.

One day I may try to plate LD onto it (unless someone has already tried and failed) as MMO would make for a nice substrate.

[jpsmith123]

I'm curious about what you got for $40.00. Is it a rod or a plate, and how big is it?

Trying to plate some PbO2 over it would be a good experiment.

[Bacon46]

Damn fine post there Bacon. However, is the material available commercially? I didn't get a chance to see the PDF as it's "pending" as I write this - so where does it leave us? What were the "nuts & bolts?" Where did you hunt up the materials? Have you gotten this unit to produce & if so, what were the results?

Thanks Charles, sorry it took so long to reply.

I have the materials for constructing an improvised version the CCVD unit on hand. The oxygen tank is from my cutting torch. The flow meter is from an Argon tank on my mig welder. The pumps or pump in my case is in the form of a high pressure airless paint sprayer. The “Mixing/Flame Nozzle I can fabricate with material I have on hand.

It’s similar to a blow torch that is fueled by atomized metal mixed with liquid fuel and oxygen. The fuel/metal mixture is sprayed into a tube where it is mixed with the oxygen and ignited creating a “Blow Torch” affect. The metal(s) mixed with the fuel will burn creating their respective oxides. The oxides are deposited on the substrate by passing it through the flame.

To try it out on a small scale I was considering placing 500ml of a fuel/metal mix in a modified HVLP (High Volume Low Pressure) automotive paint sprayer. Rather than using compressed air to spray/atomize the fuel/metal mix I would hook the paint sprayer to the oxygen tank. This way the oxygen and fuel/metal would first be mixed in the sprayer then atomized and ignited.

I have plenty of atomized Al and Zn to use as precursors in the initial tests but I am not sure what would be the best liquid fuel for this application. The thesis doesn't mention a specific fuel.

[Charles Owlen Picket]

Well I had the day off today so I threw together a small KCLO3 tank (5.G) with a paint bucket. I used a solid zinc bar for the anode (I live pretty far from town) and tried a automotive battery charger. The damn thing shuts down on me so I was forced to go with 6v lantern batteries. It appears the current is acceptable thus far.

I am getting some consistent bubbling activity but not close to a 10 amp charger. I wish there was a way to keep the thing from shutting down safely but I don't want to pull it's circuit breaker. If I had a better battery setup i would damn well go with it. I using KCL saturated solution and know that my yields will be pretty good if I can only get some juice in there.

The cathode format was a simple copper tubing circular bend around the circumference of the bucket bottom. Checking the anode, I see virtually no oxidation on the pure zinc bar. My hesitation was using anything that would pollute the KCLO3 even though I have some graphite available. This is a damn fine thing; making one's own chlorates....

[tranquillity]

A good way to measure oxidation on the zinc bar would be to weigh the bar and then let it run for a few hours and reweigh it. You may find there is a lot of zinc coming off into solution rather than the oxidation sticking to zinc bar.

[Charles Owlen Picket]

Yea....it's coming off. Bummer - in just 22 hours. I thought it could stand up. looks like shit too. Live and learn....

[Bacon46]

Yea....it's coming off. Bummer - in just 22 hours. I thought it could stand up. looks like shit too. Live and learn....

You are pretty much stuck with graphite, MMO or platinum anodes, unless you want to try a diaphragm cell. I have never tried it but I have attached the instructions out of “The Preparatory Manual of Black Powder and Pyrotechnics. It doesn't look difficult and it specifies a lead anode and cathode.

I had the same problem with my battery charger overheating. This was my solution. (http://img352.imageshack.us/img352/6996/cellpowersupply1ua7.jpg) It hasn’t overheated since. I have managed to push 22amps from that charger since that picture was annotated. I had to increase the size of the leads running to the cell from #12 to #8 to run over 18amps.

[Charles Owlen Picket]

I may give lead a try. I like the lengths you went to with the charger. I copied the picture as it may come to that. I do have a power-supply somewhere that if I can make a little circuit with a regulator in it; it would think it's not shorting....if that worked, then a charger may also. A regulator for that amp level would cost about $5.

[ChippedHammer]

Lead will not work, you will have a toxic soup in no time.

Use a computer ATX supply if you can, you can pick one up for about $10 used that will have a meaty 5v rail.

[Charles Owlen Picket]

As I understand the process, the conductivity of the electrolyte is a "short" so to speak. Would not some electronic mechanism need be in place to deal with the short circuit? I was thinking that a regulator would let the power-supply 'think" that it is not providing juice to a short but rather being consumed.

My reasoning here is that when a better battery charger was used it would shut down (that the battery was fully charged) sensing a closed circuit, etc. Without some regulator-type mechanism would not the thing get seriously hot and possibly a fire hazard?

On the lead issue: does it really matter if the chorate has lead in it: toxicity or not? Would that really be a health issue to a great extent?

[Bacon46]

As I understand the process, the conductivity of the electrolyte is a "short" so to speak. Would not some electronic mechanism need be in place to deal with the short circuit? I was thinking that a regulator would let the power-supply 'think" that it is not providing juice to a short but rather being consumed.

I'm no electrical wiz either but the way I see it is the electrolyte is the mechanism for dealing with the “short circuit”. It does this by providing resistance. The greater the distance between the cathode and anode, the greater the resistance and the lower the current will be. Voltage plays a key role in overcoming resistance. In a KClO3 cell your voltage should be around 4 vdc. Mine usually runs around 4.5 vdc at the cell.

Automotive battery chargers sense a drop in load as an indication that the battery is fully charged, not an increase. As long as there is something drawing current it should keep providing it, up to its current limit.

Most battery chargers have thermal overload protection that will shut them down in the event of a dead short, or if something, like a chlorate cell, is drawing too much current. This can be avoided by either moving the anode and cathode further apart thereby decreasing the load on the charger; or if you want to run the charger right at, or near it limits you will need to install some sort of cooling system.

As ChippedHammer stated, lead will not work as an anode in a standard chlorate cell. I only mentioned it as a possibility in a diaphragm cell becuase that is what is shown in the attachment on my previous post.

A lot of people successfully use the ATX power supplies that ChippedHammer mentioned. I only tried it once and I cooked it in an hour. Probably something I did wrong.:)

[tranquillity]

When using an ATX supply you need to connect several of the 5V or 12V leads when dealing with any decent current or it will short out.

Would it be possible to plate PbO2 onto Pb with a lead nitrate and nitric acid bath? This seems like a very obvious solution which is why I think it wont work very well but if anyone has had success I would like to know.

Using a pure lead bar is said to work for chlorate as small amounts of PbO2 are formed during its operation. You do end up with a solution of toxic lead compounds though.

[JouMasep]

You are pretty much stuck with graphite, MMO or platinum anodes, unless you want to try a diaphragm cell. I have never tried it but I have attached the instructions out of “The Preparatory Manual of Black Powder and Pyrotechnics. It doesn't look difficult and it specifies a lead anode and cathode.

You (and more in particular “The Preparatory Manual of Black Powder and Pyrotechnics”!) have me at a disadvantage there.

I fail to see how the introduction of a diaphragm could lower the requirements for the selection of the anode material -or indeed how this would facilitate/simplify the production of chlorates. (Provided that small amounts of chromates or dichromates were added in order to prevent reduction of the Chlorate ions at the cathode)

Because all you will do is ask said anode to now operate in a more acidic medium -the very electro-corrosive conditions are still there. ‘Likely worse -not better. And now you will create also the evolution of a gas. (Chlorine). This results in an additional, mechanically destructive condition.

The moment you introduce a diaphragm (i.e. read also “salt bridge”) you will have effectively have two separated half-cells as opposed to the “normal cell” as discussed on this thread.

The current is carried by the sodium ions, so they only (no other ions) will migrate from the Anode to the Cathode half-cell. All other ions remain pretty much on the half where they are / are generated. (This is the theory; in practice one will find that eventually the “pressures” of the concentration differentials become too great and thus the ANODE side will become more alkaline.)

This unilateral migration creates an imbalance -which is good if you want to produce Chlorine GAS, but bad if you want to make hypochlorite ions, or chlorate ions -at higher temperatures.

WITH MEMBRANE

Overall:
Na+ + Cl- + 2H2O +e- <--> HOCl + NaOH + H2

At ANODE:
Cl- + H2O + e- <--> HOCl + H+

And with rising concentrations of HOCl and lowering pH’s:

HOCl + HCl <--> H2O + Cl2

The chlorine will at first dissolve in the solution, but will subsequently evolve in the gaseous form.

At the CATHODE:
2H2O - 2e- <--> 2OH- + H2

I.e the CATHODE cell will become progressively more alkaline, the ANODE cell will become progressively more depleted in terms of Chloride ions. These can be replaced by addition of salt (Or hydrochloric acid, if one wants to promote the evolution of Chlorine gas.)

WITHOUT MEMBRANE:
The same initial, overall equilibrium as for a membrane prevails:

Na+ + Cl- + 2H2O +e- <--> HOCl + NaOH + H2

But now the HOCl remains in solution and is “stabilized” by the presence of the hydroxide ions.

Also, if we now raise the temperature, the hypochlorite converts to Chlorate; depending on the pH, the following will happen:

2HClO + ClO- <--> ClO3 - + 2H+ + 2Cl-
or:
2HClO + ClO- + 2OH- <--> ClO3- + 2Cl- + 2H2O

In fact, just as lead will lead (N.P.I) to ChippedHammer’s “toxic soup” sans a membrane, so will this happen in the case WITH a membrane. But now we will have at least one half free of lead salts -to no advantage in my mind whatsoever. The business end is the anode, that’s where the precious goodies are formed and now we have there double concentrated lead soup…..

And while the MMO materials are a wonderful science in themselves, as pointed out, a pretty, precious anode may well last at this or that pH or salt solution / concentration, but there is no guarantee that this will be not drastically reduced should one wish to experiment -or use it for alternative purposes. (See it slowly disappear right before your eyes…)

I am quite in favour of graphite. Get it from the suppliers of spark erosion electrodes (metal machining industry) and get the hardest grade you can get, and get a BIG piece -the lower the current density, the longer it will last and the less contamination of your solution. Importantly: do avoid grades that may contain copper powder.

You should not be sorry that you went this way first. I have found that the soaking of candle wax into the hot graphite has a similar benficial effect as linseed oil has.

If I can think of one improvement on the plain graphite electrode, it would be the plating with lead dioxide thereon. This is supposed to be difficult, but it would give a superior anode.

[ChippedHammer]

GSLD (graphite substrate lead dioxide) has been tried hundreds of times by DIY means and it always fails after a short time (usually a few days if your lucky). You are better off making a TSLD (titanium substrate lead dioxide) anode, its more difficult but it will last a long time.

[ETCS (Ret)]

The Diaphragm/Membrane Cell is used commercially to produce Chlorine Gas and Sodium Hydroxide - The Graphite Anode liberates the Chlorine which is led out of the cell to the dryer and the Steel Cathode liberates Hydrogen which is led out of the cell to a purifier. The incoming Brine solution is continuously drained from the Cathode compartment in order to collect the Sodium Hydroxide which is formed and led to an evaporator/crystallizer to remove the excess brine salt.

The Electrical Discharge Machining graphite is, as you've stated, the very best.

Your caution about the graphite containing metallic copper powder is very well taken. This grade of graphite is usually used for making electric motor/generator brushes, and therefore, is not the ideal.

Some of the books and web pages on home chlorate production advocate the use of lead plates, but obviously they've never tested their claims or are purposely propagating dis-information. Using lead creates a huge toxic mess (verified experimentally), as does using any metal that reacts with chlorine.

The use of a Computer Power Supply is a workable approach. Locate the +5 Volt adjust potentiometer and run it up to the maximum and the output will be around 6 Volts, then you can run two chlorate cells in series with good efficiency.

[Bacon46]

ChippedHammer

I’ve been running one of the MMO/Ti anodes you recommended with a Ti cathode for 24 hrs at 20 amps. So far I’ve got crystal clear electrolyte and no sign of corrosion on the anode or cathode. Sweeeet!:D

The dude that sold it to me said it could easily handle 25 amps. What is the highest current you have run one of these anodes at?

[Charles Owlen Picket]

How are you getting 20 amps again? I read back and couldn't find your current source. That's a nice jolt!

[Bacon46]

How are you getting 20 amps again? I read back and couldn't find your current source. That's a nice jolt!

I am getting it out of the automotive battery charger I mentioned in a previous post.

I decreased the secondary voltage from 12vdc to 6vdc by disconnecting one secondary leg on the transformer. Voltage at the cell is 4.8vdc. Then bypassed a fusible link on the positive lead and increased the size of the conductors running from the supply to the cell, to #6 and Installed a cooling fan and heat sink.

The electrodes are placed 10cm apart. I add 2g of K2CrO7 per liter of electrolyte and keep the temperature as close to 70oC as possible. The two biggest factors contributing to current efficiency are temperature and electrode placement but the K2CrO7 does help. I installed a 3% HCl drip running at approximately 500ml per day but it requires a lot of attention and I’m not sure how much it actually helps.
Here’s a picture of the cell I am currently running. It’s made from a 30 series lead acid battery box.

Cell (http://img80.imageshack.us/img80/96/mmocelloperating3102008sg2.jpg)

Electrodes (http://img212.imageshack.us/img212/2170/mmoanodeticathodeum2.jpg)

[Charles Owlen Picket]

This has pretty much wrapped up a lot of loose ends for me and I really appreciate it....So what's the yield? What sort of yield have you gotten and what had given you the best? Because you do this thing on the same scale as I am _trying_ to do it....I hope after all this stuff I could pull down at least a oz a day...

Have you tested the chlorate in a simple application?

[JouMasep]

The Diaphragm/Membrane Cell is used commercially to produce Chlorine Gas and Sodium Hydroxide - The Graphite Anode liberates the Chlorine which is led out of the cell to the dryer and the Steel Cathode liberates Hydrogen which is led out of the cell to a purifier.
This is a bit off topic, as I have never made chlorite; all the product I ever used was bought. But in the more recent past, I reckon it’s more prudent (and a nice challenge!) to make things the OTC way

What I HAVE made however is chlorine gas –quite a bit of it altogether; ‘ran my own little electrolytic “chlorine gas factory” for some years continuously.

I had a decently sized pool and I was sick and tired of schlepping with all the acid and HTH; the stabilizers, and the resulting ever-concentrating chemical soup which make decent sanitizing -and keeping it clear harder and harder.

To get bottled chlorine like the big municipal pools was impossible -I’d just as soon get phosgene gas to kill my cat-sized moles.

I rejected the idea of salt-water chlorination, as I did not want my filter pump running for many hours more every day, just to keep the chlorinator happy. Besides to throw in vast amounts of salt, only to pump it out at each back-wash did not appeal either.

So I made CL2 gas myself by salt electrolysis.

In a 50 l drum, I put an inverted smaller bucket, perforated at the edge with large punched holes and with most of the bottom cut out. Onto the remaining rim I had affixed an inverted large funnel. In the conical side of the funnel I had inserted a large piece of carbon bar. This was done in such a way that the bar was completely inside the funnel-bucket compartment, which is where the chlorine gas was produced.

Subsequently the drum was filled halfway with fine salt, covering (The inside of the chlorine production compartment was only partially filled. Salt water was added and covered all up to the thin stem of the funnel.

So I had the current flowing from the inside anode, downwards, thru the salt, thru the 30 mm holes around the edge of the inverted bucket, thru more salt –now upwards thru the salt solution outside. And to the cathode.

The latter item was an ugly piece of stainless steel off-cut that happened to have a surface area similar to the carbon anode. Onto this I had silver soldered a 2,5 mm core house wire. I had it just hanging in there, no need to even affix it. It looked alsmost as new (new scrap metal that is) after more than two years use.

Some details about the anode:
As said I took top grade EDM graphite. It was a square bar of 45 mm, but at one end I had turned it to round on a lathe and reduced the diameter for a length of about 22 mm.

In this end I centrally drilled a 3,2 mm hole, 15mm deep. 2,5 mm house wire was inserted and one or two wedge-shaped pieces of copper were tapped to secure the wire.

I turned up a 40 mm piece of HDPE and bored it to receive the mating cylindrical part of the anode; thru the rest of the length (total c.a 70 mm) I drilled a hole for the house wire.
The other end of the anode holder was counter drilled to receive a polyethylene 6mm irrigation hose, as protection around the anode house wire, to avoid any long term current leakage –this part of the anode holder was in proximity of the outside cathode!

The anode was now placed into an oven and heated to c.a. 110 degrees C; it was liberally coated with candle wax –staying away from the cylindrical end. This end was (also liberally) coated with hot glue. The HDPE anode holder was pre-heated somewhat with a hairdryer.

The two mating parts were now pressed together; the excess glue was wiped off.

Some 500mm of the polyethylene thin hose was pulled over the anode wire –that stuck out of the end of the holder, and pushed some 10mm into the hole with hot glue.

Lastly more wax was applied to also soak the remaining untreated end.

These electrodes served 24/7 for many months at about 5 amps, under very harsh conditions; the anode/lead connection was never compromised –even if fully submerged with saturated chlorine gas solution on the one end and the cathode quite near on the other side.

These harsh conditions were:
Evolution of gas (chlorine) has an erosive effect.
The electrolyte on the anode side was often depleted of salt; this is never good. (I left the thing for many days without attention)
Then when the Ph had risen too high, I added a dollop of HCl to the anode compartment –giving off serious loads of chlorine. I reckon that as the graphite is porous this did not much good.

Long as it lasted, in the end it did expire. And all I had to do was get a new block of graphite and turn it up in the lathe –all the other parts could be used again.

Apart from having the clearest water you can imagine –month in, month out- for the cost of peanuts in electricity (and an occasional) electrode, I had also loads and loads of strong NaOH solution. My drains were never blocked. And NOTHING else came into my pool, just continuous Cl gas and water.

I left some construction details out, but am happy to answer any questions –to my knowledge my machine was unique. But on the other hand the principle of using salt as a membrane is not that very away from the obvious.

Bad news is, my current pool is even bigger. So I bought 44 Kg of HTH on a special offer.

But perhaps I’ll get old gurgle going again –and use the HTH to make KCLO3.

Oh B.T.W, somebody on this thread asked about gold-plated anodes: it very much don’t work, leave your wedding bands where they are.

[Bacon46]

So what's the yield?
Have you tested the chlorate in a simple application?

I run my cells for 30 days. With an 8 liter cell I average 2.5kg per 30 day run using high density graphite anodes. This is starting with NaCl and reacting the resulting NaClO3 with KCl to get KClO3. With down time for maintenance like replacing corroded electrical connections etc. the cell runs approximately 700 hours in that 30 day period. Average current is ~17 amps. The current efficiency is lower on cold winter days when the electrolyte temperature hovers around 60oC and higher on hot summer days when the temperature is closer to 80oC.

700 hours * 17amps = 11,900Ah

2.5kg / 11,900Ah = .21g per Ah

A cell running at 100% efficiency would theoretically produce .66g per Ah which puts me somewhere in the 30% efficiency range.

The cells above were run using an anode with 230cm3 of submerged surface area.

230cm3 / 17 amps = 74mA per cm3. This current density will eat up a 8cm x 8cm x 64cm graphite anode in about six weeks depositing ~5g of graphite per day into the electrolyte.

If the current density is kept at or below 30mA/cm3 the same graphite anode will last many months and lose less than 1g per day.

I haven’t conducted any tests to determine the purity of the final product but I have been using it in all types of pyrotechnic compositions and it has performed very well. When reacted with concentrated H2SO4 it explodes. Any information on how to accurately test the purity of KClO3 would be appreciated.

The KCl electrolyte cell I am currently running with the MMO/Ti anode is running great and is crystal clear. I am anticipating higher production rates. If for no other reason I won’t lose any product filtering out graphite.:D

With my current power supply and the 30% efficiency I have achieved in the past, a cell larger than 8 liters is a waste of time and material. We will see in 28 days when I shut down this cell if the MMO anode changes that.

[JouMasep]

The cells above were run using an anode with 230cm3 of submerged surface area.

230cm3 / 17 amps = 74mA per cm3. This current density will eat up a 8cm x 8cm x 64cm graphite anode

You’ve done a lot of very good work on the matter at hand; that is clear.

But may I point to a small matter, and also speculate as to a problem you may have, with some remedy thereto.
From the above I see that in your current density determination, you confuse VOLUME with SURFACE AREA; the latter unit only is used to determine current density.

A square bar (sides 8x8cm) 64cm long, has a surface area of 2048 cm2 -not counting the top and bottom surfaces of 64 cm2 each.

The volumetric unit: cm3 should not come into the picture (except when you are invoiced for your anode material!)

Also, even if aware of your error above, I still struggle how you can ever have a mere “230 cm3 submerged”. This would be for submerged anode section of a size smaller than 3 x 3 x 26 cm. (Volume = 234 cm3.

Now if you would have an anode of dimensions as you gave, but you would only submerge it for a depth of 36cm (because of corrosion problems) it would make sense -even if there was still the volume / surface error. Because now you have simply displaced a comma. 8 x 8 x 36 = 2,304 cm3 NOT 230 cm3.

If my understanding is correct, and you leave that large a section of the anode above the liquid level, you should be aware off course that this significantly increases the current density.

And if you do so because of difficulties encountered with the connection between the anode and its lead, perhaps you should consider the following:

First of all, I presume you will have opted for not simply winding or clamping the wire around the electrode; drilling a hole and wedging it herein together with a thin strip of copper is the way to go.

Graphite is porous, hence even if not submerged, the electrolyte will wick towards the connection.
At this point, there exists a connection of copper of very high conductivity on the one hand and graphite of a much lower conductivity on the other-.
When dry this does not pose a problem, but when wetted with electrolyte, a miniature cell will arise due to the creation of a slight voltage drop.
Inevitably the copper wire will be oxidized and eventually the connection will get quite hot as a result of the increased resistance, accelerating the process even more.

Suggestions: Thoroughly soak the connection end of the electrode in a hot paraffin wax bath, and also use some type of resin that well sticks to the graphite / paraffin combo -this could be hot glue. (Make electrode quite hot, c.a. 120 C, when applying hot glue onto waxed electrode, this will allow partial soaking-in of glue as well.)

Note: I realise that raising the temperature of the wax / hot glue system to such temperatures as indicated (as high as 80 degrees) may pose problems with the wax and resin system. Alternative compounds may have to be sought. 60 degrees should be still OK.

[JouMasep]

Oh, and come to think of it,
230cm3 / 17 amps = 74mA per cm3.
Apart from using SURFACE AREA in the determination of current density; one also must make sure that one DIVIDES the UNITS OF CURRENT by the UNITS OF SURFACE AREA -not vice versa as you practice.

So in the example as you gave us here, the current density may have been:

CURRENT: 17 amps = 17 000 mA.
AREA SUBMERGED: (8 x36) x 4 + (8 x 8) = 1 216 cm2.

CURRENT DENSITY: 17 000 / 1 216 = 13.98 mA / cm2.

Now, nobody go and ask why with this low current density, there still is such an appreciable rate of anode attrition -go figure…..

Edit:
Hmm, I found your value of 74mA per cm3 incorrect, and hence presumed that you had indeed computed as per presentation in your post.
To your credit: even if the value was wrong, and also if there was a shift in decimal point; it does not seem that in your ACTUAL calculation you divided by unit of current.
When I continued to think along your (erroneous) line, I saw that you had NOT made this error in your calculation -only in print.
And B.T.W. may I say that I am by now getting quite interested in your new type of electrodes. Could you perhaps issue some contact details of your manufacturer's source? Perhaps I could approach them directly from my own neck of the woods.

[ChippedHammer]

ChippedHammer

I’ve been running one of the MMO/Ti anodes you recommended with a Ti cathode for 24 hrs at 20 amps. So far I’ve got crystal clear electrolyte and no sign of corrosion on the anode or cathode. Sweeeet!:D

The dude that sold it to me said it could easily handle 25 amps. What is the highest current you have run one of these anodes at?

Highest I ran one at was probably 15A (NaCl) for a few minutes before my supply shut down (not bad as the rail was only rated for 3A). I have a diffrent model to you, mine is in tube form.

You should have some crystals forming on the bottom by now.

[Bacon46]

Thanks JouMasep

I would like to start by saying I appreciate the time you spent trying to figure out what I was thinking and where I went wrong. I tried and haven’t figured it out yet. I also appreciate the gracious manner in which you pointed out my errors. You are truly an asset to this forum.

With that said; I have no idea where I came up with 230 or cm3. They appear to rectal numbers. Maybe I should start throwing out my scratch paper when it is covered with numbers that have nothing to do with what I am currently working on. Under different circumstances that kind of error(s) could be very dangerous. :o

Although I indicated cubic centimeters I was at least thinking, in square centimeters. I don’t know what the hell I was calculating!

Let me try to clear it up.

The graphite that I have been using for anodes is 3.8cm x 3.8cm x 30 to 35cm long. Only ~25cm of its length gets submerged because I hang the anode from a piece of copper pipe. See images linked below.

So; let me try this again.

(3.8 x 25) x 4 + (3.8 x3.8) = 394.442cm total submerged anode area.

17 amps = 17000mA /394 = ~43mA / cm2

The anode in this image (http://img142.imageshack.us/img142/7866/anodeassemblybj3.jpg)ran for 30 days in a 15 liter cell and 7 days in an 8 liter. At that time I had no way of monitoring the current and I kept the electrodes ~20cm apart. The electrolyte temperature was never above 48oC. There is very little noticeable loss of graphite.

Shortly after the above image was taken I installed an amp meter, and ran the electrodes 5cm apart for 21 more days. During those 21 days the current varied between 17 and 21 amps and the temperature was between 73 and 80oC. This is a picture of that anode after those 21 days. (http://img142.imageshack.us/img142/2946/anodepostoperationea4.jpg) The increased rate of corrosion is obvious.

Now that that has been straightened out; the MMO anode I am running now is working great, so I probably won’t be using graphite anodes in the future. I will PM you with the information you requested concerning the MMO anode supplier.

[ETCS (Ret)]

Bacon 46,

Kudos. Your progress reports are extremely interesting and valuable to all who may be interested in replicating your setup.

Your calculated efficiencies are quite typical for the home setup; at least in the beginning. There are a few things that can be done to increase the efficiency quite dramatically.

The most important, and perhaps the easiest, way to increase the efficiency is to get the two electrodes as close together as practicable: 3 to 5 millimeters is ideal, but not more than a centimeter. This will enable the reaction products to mix and react as quickly as possible after liberation at the electrodes, and will greatly reduce electrical current losses by shortening the ion conduction path within the electrolyte

The second, and more difficult, would be to mount both the electrodes into/onto a fashioned polyethylene frame that would enable placing the array completely and deeply under the surface of the electrolyte and maintain the very close spacing. This will necessitate a well established electrical connection to the electrodes, in the manner that JouMasep has suggested, with a good layer of conformal protection applied over the connection points to protect them from corrosion. Once this is done you'll find a very much reduced Chlorine smell as most of it will be reacted before the bubbles break the surface.

Your experiences using the new exotic electrodes for electrolysis are very instructive.

Are you using MMO electrodes for both the Anode and Cathode? Or, are you using the MMO for Anode only with Steel as the Cathode?

[ChippedHammer]

No he is using titanium (CP) for his cathode

[JouMasep]

I also appreciate the gracious manner in which you pointed out my errors. You are truly an asset to this forum.
Oh that’s all right.

I try to read and think critically. Also on my own stuff. And as I tend to speak and write fast, I sometimes miss my own errors in the first version. A good point in case hereunder

Apologies to all; I just realized something:
At this point, there exists a connection of copper of very high conductivity on the one hand and graphite of a much lower conductivity on the other-.
When dry this does not pose a problem, but when wetted with electrolyte, a miniature cell will arise due to the creation of a slight voltage drop.

To write in the style of a certain lecturer: “There is no evidence whatsoever that this is what occurs.”

The cell that arises here is the result of a dearth of electrons on the surface of the copper conductor on the one hand in the presence of an electrolyte -and a supply of such electrons elsewhere. The ‘elsewhere’ cannot be the graphite anode itself as this is very much short of electrons as well. Any “voltage drop” will be infinitesimal, never enough for the creation of an electrochemical cell. The differential between the conductivities has nothing to do with the cause of the copper oxidation.

The rest of that post stands.

Thanks for your supplier source B.T.W.

I just thought of a signature; would add it if only enabled:

Also in science: to err is human; to forgive is divine.
Just never deny a certain error - it’s unforgivable.

[Bacon46]

Thanks ETCS(Ret), I am going to work on getting the electrodes near the bottom of the cell this weekend.

Before I can move the electrodes that close together, I will have to make additional modifications to the power supply. The battery charger I am using increases its current output relative to demand. It is marketed as a 12 amp charger but with the Ti/MMO electrodes 10cm apart it pushes 18 to 20 amps depending on electrolyte temperature and pH. The lower the pH and/or higher the temperatures, the higher current output, the higher the current output the higher the temperatures, and so on. I haven’t tested the chargers limits because I’ve disabled its thermal overload protection and don’t want to fry it. I suppose if I stripped it down to just the transformer (removed the solid state regulator) I could stabilize the current output. I have limited electrical knowledge, but it appears to me that the charger regulates the current output by switching the primary voltage from one input to another. If that’s the case I could manually increase or decrease the current in the same way and achieve a more or less constant output. This will require further investigation. Another possibility may be hooking it to my 10 amp Variac and regulating the primary voltage.

On a previous cell using a graphite anode and copper cathode I placed the electrodes ~5cm apart. The current peaked at 22 amps and the electrolyte temperature at 80oC and. The only problems that this caused besides excessive anode deterioration was the conductor running to the cathode burned up and 80oC is as high as I want to go.

Keeping the temperature of the electrolyte below 70oC shouldn’t be a problem and the #6 conductors I am using now will easily handle 50 amps. The MMO anode won’t deteriorate as easily as the graphite, but I don’t want to push it much over 20 amps. The price was very reasonable but if I had to by one every month it would be cheaper to just buy the KClO3. I’ll have to take the time to figure out the surface area on this MMO anode. I haven’t done it because calculating the surface area of a piece of expanded metal is a pain. It is for me anyway.

I like JouMaseps’ method for protecting the electrical connections but I am thinking along the lines of epoxy putty or cast acrylic. There are two part epoxy putties available at my local hardware store that are impermeable to anything I have come across, and most are not conductive.

Option #1: I run an appropriate conductor through a section of PVC pipe, then make the connection to the electrode and cover it in epoxy putty. Then pull the connection into the pipe, and seal the end with more epoxy putty.

Option #2: Same as option #1 but rather than sealing the end with epoxy putty I would just partialy fill the pipe with cast acrylic.

Both of these options are permanent. Undoing it without damaging the electrodes would be very difficult if not impossible. See image below.

http://img227.imageshack.us/img227/9404/mmoelectrodeconfiguratidi1.jpg

As ChippedHammer stated, I am using a Ti cathode. It is identical to the anode without the MMO coating.

After running the cell for 96hrs I Harvested 276g of KClO3 net, after rinsing, re-crystallizing and rinsing again. I only harvested the KClO3that was easy to remove. When starting with KCl the KClO3 what precipitates has a tendency to form a single mass at the bottom of the cell. I broke that mass into manageable pieces and removed what I could easily scoop out. I probably left 50g of precipitant in the cell not to mention what was still in solution. The electrolyte temperature at the time was 60oC. It’s too early to tell for sure, but the early signs seem to indicate a significant increase in efficiency with these electrodes, even in the existing configuration.:D

Image of KClO3 harvested yesterday.
http://img227.imageshack.us/img227/7089/276gharvest031308kclo3cbg6.th.jpg (http://img227.imageshack.us/my.php?image=276gharvest031308kclo3cbg6.jpg)

[tranquillity]

Is there a reason why you have your anode positioned directly above the cathode? It seems to me that the hydrogen formed at the cathode would bubble over the anode and interfere with the formation and dissolution of chlorine. Placing the electrodes side by side may work better as they will not interfere with eachother or placing the cathode above the anode as chlorine dissolves better in basic solution.

[ETCS (Ret)]

Tranquility,

Agreed. When the electrodes are flat the planes should be vertically oriented side by side.

With round electrodes it is best to have the Cathode directly beneath the Anode.

Bacon46,

Excellent graphics and photo - you're clearly on a good innovative track.

Electrochemistry is such great fun!

[Bacon46]

I read that placing the electrodes one over the other like that would be better than side by side. I thought it was in this thread but I couldn’t find it when I did that drawing. I had a 50/50 shot at getting it right and figured if I was wrong someone would correct me.

I built that assembly and ran it this weekend. It worked fine as far as keeping the connections dry but as expected having the electrodes that close together fried my power supply. I have purchased a new power supply almost identical to one I fried. I have made the same modifications and it is currently running the cell. I built a new electrode conduit with the electrodes side by side and further apart. I will leave it run like that until I can figure out how to control the current output of the transformer.

Maybe someone can help me. The thumbnails below link to annotated images of the modified battery charger I use as a power supply. There is a part indentified as a “Black Thing”. I would really like to know what that “Black Thing” is and what it does. Without this device the transformer doesn’t seem to work at all. If I attach my multi meter directly to the secondary leads at the transformer I get no reading. If I take a reading after that “Black Thing” it reads just under 6vdc. If I attach the other secondary it reads 13vdc.
What the hell is that thing and why won’t the transformer work without it?:confused:

http://img81.imageshack.us/img81/8766/powersupply002al3.th.jpg (http://img81.imageshack.us/my.php?image=powersupply002al3.jpg)

http://img81.imageshack.us/img81/1379/powersupply003lp0.th.jpg (http://img81.imageshack.us/my.php?image=powersupply003lp0.jpg)

[ETCS (Ret)]

Bacon 46,

Your photos were good - I downloaded them and lightened them up a bit with IrfanView to get a good clear look.

The mysterious "Black Thing" attached to the aluminum heat sink is the "Diode Pack" which rectifies the AC output of the transformer into pulsating DC. It consists of two diodes which are fed AC by the outer two terminals of the transformer secondary, and the center terminal of the transformer secondary connects directly to one of the output DC lines which would attach to the battery. The diodes in the pack are connected "belly to belly" and their common connection goes to the heat sink itself where the other output cable connects.

Your transformer is "center tapped" so that it consists of essentially two secondary windings which are out of phase 180 degrees. The voltage measured across each half of the secondary would be about 13 volts AC; and the voltage measured across the two outer terminals of the secondary would be about 26 volts AC.

When all the wires are connected to the Rectifier Diode Pack the output to the battery will be full wave rectified DC pulsations. By disconnecting one of the secondary connections to one side of the diode pack the output becomes half wave rectified DC pulsations. In each case the peak voltage of the pulsations will be the same.

By disconnecting one side of the secondary to the diode pack the half wave pulsating DC as read on a voltmeter will be half that measured when all is connected to provide a full wave output. The voltage hasn't been cut in half; the number of pulsations per second has been cut in half, therefore the average as read by the voltmeter is lower.

The easiest way to lower the output voltage would be with the variac you mentioned before. Since the AC input to the charger at full secondary load would be about 2 Amperes, your 10 Ampere Variac would easily handle it.

Be sure to hook both wires to the diode pack to get full wave output when you do that as full wave is more efficient than half wave pulsations.

It would be possible to build a small add-on circuit to decrease the voltage electronically by means of "Active Rectifiers" or controlled rectifiers such as are used in electronic lamp dimmer devices. If you're interested let me know.

By the way, on your "fried" charger - it is most likely that you've burned out a diode in the diode pack. Those are relatively cheap and relacing it would probably salvage the unit. That is, unless the transformer itself is fried, (less likely), in which case it could be manually re-wound.

Either way, with a little work, it can be made good as new.

[Bacon46]

Thanks ETCS (ret)

Now I know why I wasn’t getting a reading at the transformer. I was trying to read AC voltage with the meter set for DC.

The transformer in the power supply I “fried” was fine. I showed no signs of being burned. The diodes in that charger were exposed on a printed circuit board. I will fish it out of the trash and take the board to Radio shack and match everything up and rebuild it. That charger seemed to be more robust than the one I am using now. It had a short burst, 75 amp setting for starting cars with dead batteries. That may be why.

[ChippedHammer]

From the looks of things you are pushing way to much current through your rectifier (and transformer for that matter). I wouldn't expect it to last to long in its current state, I doubt radioshack will have the exact rectifier parts but its easy enough to buy a suitable bridge.

I recommend you give rewinding a microwave or arc welder transformer a go.

[Bacon46]

I recommend you give rewinding a microwave or arc welder transformer a go.

I have a microwave transformer but currently lack the knowledge to rewind it.

I would like to bring 120 VAC down to 5 VAC and be capable of pushing 30 amps

I have searched the internet and everything I find is written in “Electronics”, a good deal of this language I don’t understand. I am sure I am up to the task but I need instructions written in plain english. I need “Transformer Winding for the Complete Idiot”. Do you know where I might find something to that affect? Website, book or whatever.

[Charles Owlen Picket]

On the FTP there is a collection of material on just that type of transformer stuff. Grab the "filelist.txt" and do a hunt for "transformer" and find the exact sub-directory....the information is out there; I know, as I stumbled upon it getting material on Tesla Coils.

[Bacon46]

I haven't figured out how to access the FTP:confused:

I ran across a cylindrical glass flower vase at a local craft supply shop that is 76cm tall with a 15cm ID. I thought it would be interesting to watch the electrolysis and precipitation in action with new MMO anode and Ti cathode so I transferred the contents of the 8 liter cell I had running into the vase. I reconfigured the electrode conduits so that I could place the electrodes near the bottom of the cell forcing the chlorine to rise through 80% of the electrolyte on its way to the surface, allowing the chlorine more time to dissolve before it reached the surface. Another advantage to the tall cylindrical configuration is it decreased the surface area at the top of the cell from 1660cm2, in the battery box, to 182cm2, reducing the rate of evaporation. One disadvantage is it’s difficult to harvest the KClO3 that precipitates to the bottom of the cell.

The cell ran in the previous “battery box configuration” for 115 hours. In that time I harvested 816g of KClO3, or a little over 7g per hour. The electrolyte temperature was 60oC when I harvested so I am sure there was a considerable amount of KClO3 dissolved in the electrolyte.

For the first 196 hours the cell ran in the current “vase configuration” the production seemed to drop significantly. Only ~3cm of KClO3 had accumulated at the bottom of the cell. I assumed this was because I hadn’t adequately replenished the KCl in the electrolyte as I was harvesting the KClO3, so rather than the standard 3% HCl drip I have been using I decided to add 35% HCl to a saturated solution of KCl at 100lm per liter and drip it into the cell as close to the rate of evaporation as possible, which is currently ~600ml per day. 24 hours after starting that drip the amount of precipitant at the bottom of the cell doubled. It is now producing KClO3 fast enough so that I can see it precipitating out of the electrolyte.

My next project will be designing and building a heavy duty power supply specifically for this application.

Video of the cell in operation and KClO3 precipitating. (http://img532.imageshack.us/my.php?image=glasscellmoviers6.flv)

[Charles Owlen Picket]

NICE work with the video! I could tell you were pumping out the amp's there with all that bubbling. Very neat.

[ChippedHammer]

Just finished my 4th harvest from my 7L glass cell, probably time to purify one or two of the large bags I have filled with chlorate crystals around here.

My cell looks like Bacon46's but a bit fatter and not as yellow :)

I found that if you let the cell sit for a day or two (not running) the solution goes clear (and the chlorine smell goes away).


Fuck graphite :D

[Bacon46]

My cell looks like Bacon46's but a bit fatter and not as yellow :)
Fuck graphite :D

Agreed; graphite would be a last resort since using these MMO anodes. I still have two graphite cylinders 14cm in diameter x 36cm long. I’ll save them for a rainy day. The last time I was at the salvage yard I saw a piece of graphite 14cm in diameter x 1.5m long and thought about turning a 200 liter plastic drum I have into a chlorate cell and using that as an anode. I would have to sacrifice my mig welder to power the thing and it would take me a month to make the electrolyte and another month to process it once complete so I decided against it.

It’s still early, but it appears the MMO coated Ti anode has double the production efficiency of graphite. I say it’s still early because I haven’t actually been able to run a cell with the new electrodes for my usual 30 days. I keep frying power supplies. I cooked two automotive battery charges in ten days. One of those chargers had successfully run at least five, 8 liter cells using graphite anodes. In the ten days that I did run, I harvested 2.2kg of pure white KClO3. I have to go back through my notes and calculate amp hours but I think I am close to 70% efficient.

This is the first time I have started with KCl. I usually start with NaCl and react the resulting NaClO3 with KCl to get KClO3. Using that method with graphite anodes I netted an average of just over 2kg of KClO3 from a 30 day run. Had I not fried the power supplies and this last cell ran 20 more days, at the rate it was running I would have netted over 6kg of clean KClO3. Impressive by my standards!

I decided to attempt to build a power supply specifically for chlorate production. My goal was a power supply with 120 VAC primary voltage and 3.5 – 4.0 VDC secondary voltage, and the ability to easily push 50A. Then I could run it at 30A without worrying about it overheating. This is how I went about it. Keep in mind I am electronically challenged. Here's a picture of the power supply. (http://img100.imageshack.us/img100/8952/powersupply007vw4.jpg)

Basically I just wired two transformers in series. Transformer “A” is a factory wound unit that steps 120 VAC down to 12 VAC. Transformer “B” is a much larger transformer that I hand wound to drop the 12 VAC from transformer “A” down to 5 VAC. The secondary windings of the rewound transformer consist of 10 rows x 10 layers of #10 AWG. I lost count on the primary winding but I used #14 AWG and the secondary voltage worked out great. I then installed the heat sink and diodes from the last battery charger and ran the +5 VAC through that with an end result of just over +3 VDC.

I have run this power supply for over 24 hrs. There is plenty of action at the anode but the current sucks. With the cell running the voltage and current are as follows:


Transformer “A” Primary…………………………………………………….120VAC @ ~320 mA
Transformer “A” Secondary (Transformer “B” Primary)……… 12VAC @ ~3.45 A
Transformer “B” Secondary………………………………………….……….4.7VAC @ ~2.80 A
Anode……………………………………………………………………………………3.12VDC @ ~2.08 A

Leave it to me to wind a transformer that lowers the voltage and the current.:( Since other than disconnecting a couple of wires in a battery charger, this is my first attempt at transforming power; I consider it a success that I wound up with any secondary power at all. I will keep reading and get it figured out.

The electrolyte is yellow because I piss in it twice a day to make up for evaporation and to adjust the pH. At 20 amps you get quite a rush.

It actually 2g of potassium dichromate per liter of H2O that I add in the beginning that makes the electrolyte yellow.

We don’t want any newbs pissing in their chlorate cell. Especially if it’s running!:eek:

[ETCS (Ret)]

Bacon 46,

Well, now you're on the right track for sure! Your approach is very innovative, and in theory, viable. However, it is not sufficiently robust nor efficient. Still, you have earned an "A" for effort though!

May I make a couple of suggestions?

Neither of your transformers are capable of delivering the magnitude of current flow that you're wanting to achieve. It would be best to utilize one of your battery charger transformers with an add-on non-dissipative voltage reduction circuit. (I'll post a schematic diagram for you as soon as I'm able.)

The diodes normally used in battery chargers are conventional Silicon Rectifier units. It would be best to replace those with Schottky Diodes which have smaller forward voltage losses and therefore greater efficiency.

This will be continued on the morrow...

[ChippedHammer]

Novel idea but your primary transformer is way to small for any decent current and the secondary transformer has been designed to run off 120v not 12v so you cant expect it to be efficient at all. I suggest you use a single large tranny with fat windings (MOT's are great here) and use the biggest bridge and capacitor you can find.

Here is a good starting point for MOT's (http://bundybovines.com/5361/chlorate/winding.html)

(copy of CapeCanaveral's site which seems to be be down atm)

[Bacon46]

Novel because it doesn’t work!:o

I appreciate the help.

I removed the secondary transformer “B” and am now running transformer “A” off of my variac. It’s puttering along at 3.9VDC @ 14 amps. I did manage to get the electrodes to within 1cm of each other no that I have the voltage down where it should be.

I think I will try Chippedhammers MOT with ETCS(Ret)’s non-dissipative voltage reduction circuit (assuming I can build it). Both of my battery charger transformers are shot. One is not worth rewinding due to corrosion of the core. Both of the transformers shown in my previous post are much larger than the ones in a battery charger, but I did happen to find a MOT that I had been saving for just such an occasion.

I still can’t get over the production with the MMO anode and the Ti cathode. I must have made an error logging the Ah on this last cell, because when I do the math I am way too close to 100% efficient and I had all kinds of power supply trouble. I am going to start a fresh cell today and compare the results.

[ETCS (Ret)]

Bacon46,

Your determination to see this through to a successful and fruitful conclusion is reminiscent of the "greats of old!"

All things considered, perhaps this would be the best solution:

http://www.goldmine-elec-products.com/prodinfo.asp?number=G16217

Switching Power Supplies are by far the better option as they are smaller and more efficient than the more conventional line powered transformer supplies. The one that Goldmine has on sale now is the ideal voltage and current range for your application.

I often get carried away with the "do it yourself", approach since electronics is my training, and therefore fail to appreciate how confusing it is to those who aren't in the same boat.

I have used the 5 Volt output of switching supplies many times for electrolytic cells and they have performed admirably. Always keep them well separated from the cell by several feet of heavy wiring to avoid contamination by bubbling/spray produced aerosol which is quite corrosive to metals.

Again, your energy and enthusiasm are remarkable - success is very, very near!

[Bacon46]

Thanks ETCS(Ret)

The link is broken but there was enough information to get me to the power supply. It’s just what the doctor ordered and only $40.00. I am pretty sure the first battery charger I fried cost more than that. I will order one before the sale ends.

I am a hopeless “Do it yourselfer” (I don’t think that’s a word) and it’s no fun if I already know how to do it. Once I figure out how to do something I will move on to something else that I have never done. As long as it looks like it would be fun to try and I have a better than average chance of surviving the attempt, I’m game. I am actually that way in my professional life as well. When I get three consecutive chlorate cells to run over 60% efficient for 30 days I will move on. By that time I will have enough KClO3 to last a few years. My biggest problem will be picking the next project. So many projects, So little time!

I have already rewound the MOT transformer. I am going to round up a heavy duty rectifier and run it off of my variac for the time being.

[jetz]

I’ve been running the same kind of anode in a cell for a few days now at 5vdc 4-5amps, which for the size cell I’ve set up is to low IMO. It’s a 2.5lt cell with 850g of KCl in it. I’ve been trying to get the amps up over the last few days and I think I’ve done that though I don't know how long it will last.

I’m using a PC power supple supply to run it, I was getting the 5vdc 4-5amps off the 5.3vdc wire. I tried the 12vdc wire but it just fried the wire pretty good, it was running at 15amps. What I’ve done is try to lower the volts by adding some kind of resistor. Being electrically challenged I had a rummage in me misc electronics box but couldn’t find any thing so in the end I just used a graphite rod which did the job.

It knocked it down to 6vdc 11.5amps the wires aren’t getting as hot but the connection to the power supply are getting very hot and so was the graphite rod to fix that I just added some CPU fans to cool thing down which seems to be working.
It will be interesting to see how long the power supply lasts.

[Bacon46]

ChippedHammer

The rewound microwave transformer did the trick, combined with a 10 amp variac and a 600V, 40A bridge rectifier I have a damn fine adjustable power supply. It’s 9” wide, 9” tall, 16” long and weighs around 50lbs, compared to the solid state version ETCS(Ret) recommended which is 2.375” wide, 1.7” tall and weighs 22oz but what the hell, I shouldn’t be moving it much anyway. The only thing I had to buy was the rectifier, everything else I had on hand.

I really like the option of easily changing the secondary turn count that the MOT gives me. I used standard #10 strand as secondary wire. It’s no problem to add or removes turns if needed.

Right now I am running with the transformers magnetic shunts in place. The voltage and current are very stable in this configuration. I may try running without the shunts on the next cell just to see how it acts.

A good heat sink and a cooling fan for the bridge rectifier is a must. That little bastard gets HOT!! I bolted the rectifier to a piece of .125” thick aluminum plate then secured that in place with the rectifier facing down. I then attached a computer processor heat sink to the aluminum plate directly over the rectifier. I used thermal grease for both the rectifier and the heat sink. Combined with the cooling fan I have been using, this setup seems to be performing well. :D

I attached an image of the completed monstrosity!

[ETCS (Ret)]

Excellent work Bacon46!

The Microwave Oven Transformer re-wind is very rugged and will last for centuries.

The Variac controlled AC input will provide effective adjustment of the output current to suit a wide range of needs.

For high current/low voltage applications big and bulky can be very good.

For heavy current loads the Silicon Bridge Rectifiers are very lossy and do develop considerable heat.

Once you determine the ideal number of secondary turns for your needs, you can enhance the efficiency of your supply and reduce the Diode heat losses by;

Doing a final re-wind of the secondary as a center-tapped configuration,

Using a Schottky Diode 3 terminal full wave rectifier rated at 60 Amperes in a TO-220AB package in place of the Silicon Bridge. These Schottky Rectifiers cost about 4 bucks from Mouser, and are rated at 0.625V Forward Voltage Drop at 30 Amperes. If Schottky's run hot under very heavy current load, then additional units can be paralleled to distribute the small losses.

Of course, there's no real need to make those changes - your setup is working fine as it is.

But then again; if it works, tweak it...


Afterthought:

If at some time in the future you'd like to experiment with a switching supply to provide the low voltage/high current, this web page has a fairly simple circuit that would be worth investigating:

http://home.comcast.net/~ddenhardt201263/desulfator/highpower.htm

[ChippedHammer]

Nice job, you should be able to pull some serious amps with that setup :D

I was going to recommend a CPU cooler (an old Pentium 4 copper cored HSF works very well) but you seem to have beaten me to it :)

[Bacon46]

But then again; if it works, tweak it...

Absolutely; I must continue tweaking it, even if it is only a slight improvement. I am currently seeking professional help in the hope of one day being able to leave well enough alone.:D

Until then, I am going to rewind the transformer as a center tap and switch to the Schottky Diode 3 terminal full wave rectifier. Is this the rectifier you were referring to? Schottky Rectifier (http://www.mouser.com/Search/ProductDetail.aspx?qs=hatmUE2mJxRqHOg8wHeZJg%3d%3d )


There is a reason, other than my uncontrollable desire to “tweak” things, for wanting to switch to the Schottky rectifier. Sunday I harvested the precipitant, replenished the electrolyte and increased the output to 4.5VDC @ 30 amps with problems. The current and voltage remained constant and the electrolyte temperature stayed around to 50oC. In the first 12 hours at this setting approximately 6mm of KClO3 precipitated. In the eight hours following that, while I was asleep, an additional 15cm of KClO3 precipitated completely burying the electrodes. The KClO3 crystals bridged the gap between the electrodes and fried the bridge rectifier. Oh well!

If I am going to have a problem I suppose producing chlorate too fast is a good one to have. I haven’t processed all of the chlorate but I’m confident this cells efficiency is well above 60%.

Just to get things back up and running I installed another bridge rectifier and changed the layout of the components in the power supply enclosure so that the rectifier is at the end closest to the cooling fan, rather than in the center between the transformers. I also replaced the plastic mounting brackets that where holding the rectifier heat sink with aluminum brackets so that some of the heat can be dissipated into the enclosure.

Jetz

Although I have heard of many people using computer power supplies to power chlorate cells I haven’t had any luck with them. I only made one attempt and fried it in less than a day. I probably hooked it up wrong.
I would keep my eyes open for an old microwave. You might want to look at your local thrift shop, Goodwill, Salvation Army etc. If your patient, you may eventually find one in a dumpster.

[ETCS (Ret)]

Yes, the Schottky package you found will do very nicely.

Well, unexpected, but good, problems do arise from time to time. A circuit breaker in the high current secondary line might be another addition to consider.

You've established one thing for certain: It is possible to produce Potassium Chlorate directly in a properly designed cell and replenishment system, with enough bottom space to make allowances for the precipitation of the desired salt. Going the Sodium Chlorate route is now an option.

Regarding the use of Computer Power Supplies:

Select one that has approximately twice the output current capability at 5 Volts that you desire to operate your cell at.

Use only the 5 Volt output, or the 3.3 Volt output, and not the 12 Volt output.

Used Computer Supplies are very often loaded with dust buildup/deposits all over the inside circuitry so it is necessary to open their covers and clean them out thoroughly. I use a small vacuum cleaner and a small paintbrush; to loosen the dust and suck it into the vacuum.
Get into every nook and cranny of the circuit board and heat sinks to dislodge and remove all dirt buildup completely and clean the fan blades especially well.

When connecting the supply wires to your cell use all of the wires available for the 5 Volt Positive (Red) or 3.3 Volt Positive (Orange) output, and all of the Common (Black) wires for the Negative.

As an added feature, it is possible to replace the on-circuit-board output voltage adjustment with an external potentiometer to enable tweaking the output voltage/current.

Once it's been cleaned up, hooked up, and energized, monitor cell current and keep it at about half of what the Computer Supply is rated at and it should go a long time.

Check the internals for dirt/dust buildup and clean often as necessary.

The pleasures of dabbling in the mysterious realm of Electrochemistry are sure hard to beat!

This record of your progress is likely to become a classic Bacon46!

[Bacon46]

Well the results are in. Starting with KCl as the electrolyte the MMO anode and Ti cathode combined with the MOT/Variac power supply produced 2.84kg of KClO3 in 5153.5 Ah. That puts this cells efficiency at ~59%. That’s almost twice as efficient as my best graphite anode cell and only 1% short of my target of 60%. Close enough! :D

What I really like about this setup is the ability to turn up the current a produce over a kilo of chlorate in less than a week. Processing consists of rinsing out the K2CrO7 and one re-crystallization for good measure.

2.84kg is after processing and re-crystallization. I added 50g to the total for losses during processing due to the inherent inefficiencies in my improvised processing methods. To make matters worse, I had two chrome plated clamps holding the electrode conduit over the cell that corroded and dropped a bunch of black crap into the electrolyte increasing the losses by adding an additional filtering step.

The MMO anode and Ti cathode are holding up well. After more than 10,000 Ah there are no visible signs of corrosion on either of them. They both look as good as the day I bought them.

I think I will run two more cells before giving it a rest. Both will start with NaCl, one to produce NaClO3 and the other I will react the resulting NaClO3 with BaCl2 to produce Ba(ClO3)2.

Something else I changed is the acid drip. I was using a I.V. drip I purchased from a medical supply house. It worked okay but had a tendency to stop dripping and required a lot of attention. I replaced it with a one gallon plastic milk jug with a pin hole in the bottom. I completely fill the milk jug with 3% HCl squeezing it a little to remove all the air and screw on the cap. It emits a fine stream for a minute or so and then slows to a drip. I then hang it so that the acid drips into the cell . It continues to drip for a couple of days as the milk jug slowly collapses. If the drip slows too much I just crack the cap for a second to allow a little air into the jug. This works much better than the I.V. set and it's free.:D

[ETCS (Ret)]

Reviewing the entire topic once again, it is needful to give additional thanks where thanks are due.

ChippedHammer has contributed greatly to the ease with which the Chlorates may be prepared by Electrolysis with his valuable suggestion to use the MMO Anode material, utilization of the Microwave Oven Transformer re-wind as a sturdy power source, and his encouragement to obtain the Really Good Anodes from vendors on Ebay.

Many thanks friend for your groundbreaking experiences which served as an inspiration for Bacon46 and others who are benefitting from your input.

[Bacon46]

ChippedHammer has contributed greatly to the ease with which the Chlorates may be prepared by Electrolysis.
Many thanks friend for your groundbreaking experiences which served as an inspiration for Bacon46 and others who are benefitting from your input.

I agree; taking ChippedHammers advice on those two things increased the production from my cell 90%. That is greatly appreciated.

Now I’m bored. There is nothing left to tweak unless I add digital pH and temperature control. :D Maybe I’ll try that after I use up the 8kg of KClO3 I have now. It’s so easy to produce NaClO3 now I can use it for weed killer.

[Charles Owlen Picket]

MOT's are scary (to me) due to the "out of the box" current & voltage but I've heard that rewinding the secondary could get the voltage down to below 90 Vac & make the concept safer for those with less HV affinity. Some of the xformers I've seen from microwave oven's are rather shoddy...but some are higher quality & would lend themselves to alteration.

IF someone is new to the concept of Chlorate production I would suggest that they first of all re-read the post of Bacon & Chippedhammer throughout this & other threads. At this point I believe that an enormous amount of information exists to get almost anyone up and running to achieve home Chlorate production on a near lab scale.

There is enough information just from what I've read thus far for an EXCELLENT pdf on home production. I've noticed that it's times like this that the repeated questions arise on well trodden ground. And that's a shame because the newer input at this point will be actually "ground breaking" & on occasion is lost because of re-hashing old material. Critical issues such as voltages, sourcing, or return percentages are often lost in repeating basics for those newly interested in a technique.

This has happened time & again with synthesis & DIY discussions. If someone is just joining this discussion: please read the past material.

[megalomania]

There is enough information just from what I've read thus far for an EXCELLENT pdf on home production.

This is exactly what I was thinking. I could compile the information into the chemical synthesis area of Rogue Science, but I am not versed on the intricate details of this type of production. I could brush up, but I have other areas I am better skilled at that I would rather work on.

This would be a good use of my user contribution system I am still working on.

If someone wants to write up a full page on chlorate production using the information in this page, I would very much appreciate it. The information can be edited over time by multiple contributing authors, so several submissions would be fine. I would prefer for now that the write-up be in a word document with embedded graphics, if any. I would then edit and format the info on the document into a webpage.

I have Office 2007, so I can use the new docx files and the legacy doc files.

I know I should spend more time developing the user contribution system. It is a complicated challenge, but if I don't build I won't get any submissions will I? A PDF file would also be a very likely possibility. I need to brush up on my Indesign skills more, but I would like to make a PDF version of the information on my website. To make it look nice, professional, requires more than just printing to PDF. It is for this reason I keep all my research and laboratory synthesis in word, not just HTML.

If anyone would like to coordinate on a formal write-up for chlorate production, PM me for details regarding info, style, graphics, etc. Multiple people can collaborate, I can facilitate collaboration to get this done.

[ChippedHammer]

Now that you mention it I did get halfway through writing a guide for 1st timers but I never really got around to making it live up to my expectations (which were quite high).

Sounds like a plan :)

[ChippedHammer]

Well me and Bacon46 have decided to give it a shot. If anyone feels like contributing or has any suggestions then by all means PM one of us.

[Lewis]

I just got back from a small specialty electronics store in the industrial section. I had them order me a small, 5 volt, 20 amp switching power supply. I'll soon be trying it out in my first large chlorate cell.

It should be in next week. Now I need to worry about anodes. Pictures to come.

[Charles Owlen Picket]

Anodes gave me the biggest headache. I actually should have listened to Bacon from the beginning but I thought I could get creative and find a cheap or local substitute. Only my opinion but folks are better off buying a professional material right from Jump-Street instead of playing with every-fucking-element-they-can-lay-their-hands-on.

[Bacon46]

Only my opinion but folks are better off buying a professional material right from Jump-Street instead of playing with every-fucking-element-they-can-lay-their-hands-on.

I agree, but I probably would have done the same thing if I hadn't stumbled onto a ton of graphite at a local salvage yard. Literally a ton of solid cylinders, ranging from 5.5” to 12” in diameter and from 6” to 60” long. I got as much as my Blazer could hold for $20.00. The guy didn’t even know what it was.:D

[Lewis]

And how would you turn something of that shape into an electrode?

[Bacon46]

And how would you turn something of that shape into an electrode?

You can use it as, is if you are planning a large cell. I cut it into the desired sizes with a band saw. I had my son hold a shop vac next to the blade of the saw as I cut it but it was still a very dirty job. I wound up with graphite everywhere.

Thanks to ChippedHammer's MMO anode suggestion I won't have to deal with that again. I think I will have the remaining graphite machined into rocket nozzles.

Since I am on the MMO anode subject; I have been running the anode continuously for the last ten days in NaCl electrolyte at just over 30 amps with an electrolyte temperature of ~60oC and it is performing flawlessly.:D

I intend on running this cell for 22 days at 30 amps without any attempt to control the pH. I want to compare the production to previous cells where I used an acid drip to see whether this method of improvised pH control is worth the trouble. If it turns out that this crudely improvised method made a difference I may tweak it and invest in an electronic pH control system.

[Lewis]

Interesting. And I bet that graphite made amazing rocket casings/nozzles!

I see there is an ebay seller with MMO mesh anodes for forty bucks. At this point it's looking like the way to go. Of course, then I'm tempted to get a Ti cathode to go with it. Is it worth it at all for purity's sake?

It seems like even though a metal may be cathodially protected, there will inevitably be some material deposited in the electrolyte.

[Bacon46]

This evening when I checked on the cell I have running the voltage had dropped from 3.54 to 2.2 VDC. The current had not changed and was stable at 31 amps. The electrolyte temperature was normal at 60oC. I left it as it was and came back an hour later and the voltage was back to normal at 4.5 VDC. It is a nine liter cell that has been running for 13 days and has 9220 Ah on it.The voltage has never dropped below 3 VDC.

Does anyone have any idea what may have caused the voltage drop and is there any reason for me to be concerned?

[ETCS (Ret)]

Where do you have your voltmeter connected to make the measurement?.

Could it have been a faulty connection to the voltage monitor points?.

Since the measured current flow was normal it would seem the voltage at the cell should have been in the normal range as well.

Let us know what you discover.

[Yafmot]

I recently acquired a 6x10" piece of Pt coated Nb mesh, but with no conductor bar or any other method of connection. What I'm planning on doing is to melt a piece of Indium strip solder onto the edge. I'm also going to strip 3 or 4 inches of insulation from the positive lead and solder that on. Then I'll take the whole mess to a jeweler and have them apply a couple of coats of Platinum to the bar and wire with one of those electrified felt pens they use for coating small articles with various metals.

Then I'll coat the wire from the bar to about 3" above the bare metal with Plasti-Dip or a similar product, so that if any electrolyte does migrate onder the coat, it'll have a long way to go to get to bare Copper. No point in getting the best available anode materials, only to connect it with something that'll corrode and fall apart in one or two runs.

Whaddya' think?

[Bacon46]

A variation of the method posted by JouMasep (Post 154 in this thread) (http://www.roguesci.org/theforum/showpost.php?p=101601&postcount=154)using hot glue to protect the connections should do the trick. I use hot glue in combination with epoxy putty. You have to replace the hot glue once in a while but it’s no big deal. The hot glue in the cell I am running now has over 10,000 Ah on it and it’s still going strong

[ChippedHammer]

I don't really like using hot glue, after a while it goes milky white and looses its adhesion (found out the hard way early on when the seal around my vent hose failed and I woke up to a garage with a very strong chlorine smell). It works ok for a week or two but its not permanent. If you want something that wont deteriorate then use epoxy. I found that most manufactures have chemical resistance charts, pick a product that will resist bleach and it will be fine.

[tranquillity]

I tried using epoxy only to find it wont stick to polypropylene. I have since covered the joints and electrical connections with hot glue and am yet to put the cell into service hopefully it doesn't corrode and leak chlorine too quickly. Will post results after my first run.

[ChippedHammer]

Polypropylene and polyethylene are a bitch to glue, nothing works on it due to their high chemical resistance. There are special glues out there that require a pre-coat of a solvent (fairly sure its mek) but they may be hard to find.

Silicone may work as well.

[Bacon46]

This is a slide show (http://img532.imageshack.us/my.php?image=electrodeassemblyle3.flv)of the system I am currently using. It consists of attaching the electrodes to a PVC pipe cap using a combination of regular epoxy, epoxy putty and hot glue, then attaching the cap to a section of pipe. This way I can submerge the connections allowing me to place the electrodes at the bottom of a 2 ft. deep cell. I haven't found anything that won't eventually give out when completely submerged.:(

The system in the slide show lasted 11380 Ah before failing. That’s 16 days completely submerged in a cell running 30 amps, with an electrolyte temperature ranging from 60 to 65 degrees Celsius. There were a couple hours of down time. Scheduled completion for the cell was 22 days using 60% as the anticipated efficiency. If I had replaced the hot glue 10 days into the run it would have made it no problem.

If you’re not planning on submerging the connections this system should last indefinitely. I have considered trying aquarium silicone in place of the hot glue, but haven’t yet.

Before applying any adhesive to PVC I sand the surface with 120 grit sandpaper then clean it with PVC cleaner. PVC cleaner is a combination of MEK, Tetrahydrofuran, Cyclohexanone and Acetone. Available anywhere PVC pipe is sold.

[Bert]

At one time I worked in an R&D electronics shop. We fairly often would "pot up" circuits in either epoxy resin or silicon (RTV). There were grades of resin that had additives for enhanced thermal conductivity, but were still electrially insulative. I'd guess that filling the inside of your pipe cap with clear silicon would have had a better result than hot melt glue.

[Alexires]

Bacon 46 - I like the look of your electrodes. But surely there has got to be a better way.

Ever thought about trying gasket sealant they use on vehicles? Maybe pool sealants (for instance, the things listed here (http://www.poolcenter.com/service_repair_supplies_sealants_lubricants.htm).)

[Bacon46]

I haven’t tried the RTV sealant or silicone yet. I have tried the A-B epoxy putty at the bottom of the linked page. It lasts for a week or so.:(

I have some powdered plastic used in thermography (raised printing). It melts at around 565oC and didn’t burn when I held a flame from a MAPP gas torch directly on the molten material. When it cools its durometer is similar to PVC and it sticks to whatever it touches. I still have some stuck to an anvil from a smoke experiment that I will have to remove with a torch and putty knife.

I am going to melt a bit of this stuff and pour it inside the pipe cap. I think this will last indefinitely. Unfortunately it is not an OTC material. It can be ordered over the internet but probably isn’t economically sensible for this application. I aquired 3 lbs of the stuff for free.

I mentioned casting the electrode connections and conductors into acrylic (fiberglass) resin in a previous post. This would definitely be impermeable and would last for years, but you would have to be certain that you where always going to use the electrodes in the configuration you cast them in, because removing them from the casting without damaging them would be difficult.

On a related subject:

ChippedHammer, Charles Owlen Picket, ECTS (ret) and I have been working on the formal write up on chlorate production discussed back in post #190 and #191 of this thread. I am currently writing the chapter on power supplies. I have everything covered except modifying a computer supply. There is a ton of information available over the internet on how to do this, and I’m sure I could get permission to copy it, but since this write up will eventualy end up in a "Member Contributions" section it would be best if all of the information in the document come from the experience of the members of this forum. I have only made one unsuccessful attempt at this, so I have nothing on the process. I searched the forum and didn’t find anything.

Does anyone have, or is anyone willing to write a comprehensive set of instructions, on modifying a computer power supply for use in chlorate electrolysis? Preferably with images and based on thier own experience. If so please PM me so we can discuss format etc. Or, if the information is already available here can someone point me in the right direction?

And, since I’m on the subject of power supplies; yesterday I needed to charge my car battery, anyone who has been following this thread knows, I fried my automotive battery chargers making chlorates. I didn’t want to go out a buy another charger so I figured I would try and use the MOT/variac power supply I built a couple weeks ago to charge the battery. I used the clamps off of an old set of jumper cables to attach the power supply to the battery, cranked the variac up to 120 V and Wha La, it worked great! 15 volts at around 7 amps :DCheck it out! (http://img158.imageshack.us/img158/4606/motbatterychargermw0.jpg)

[ChippedHammer]

Does anyone have, or is anyone willing to write a comprehensive set of instructions, on modifying a computer power supply for use in chlorate electrolysis? Preferably with images and based on thier own experience. If so please PM me so we can discuss format etc. Or, if the information is already available here can someone point me in the right direction?

Yes, I'll shoot you a email

[Yafmot]

I feel a little a little like Dorothy at the end of "The Wizard of Oz." After beating the bushes and wracking my brain (or maybe wracking the bushes and beating my brain), I did the obvious and called the guy who supplied me with the Nb/Pt anode grid. He said no problem, he'd just send me strips of the same stuff, and I can just spot weld them. He sent me a 12X2" strip to cut up & use for both conductor bars and a lead, plus a 3X8 strip to use for a cathode.

So let's see. A three gallon plastic bucket. A cathode. An anode. A 40 Lb sack of KCl. Now all I need is a power supply and maybe a little Hydrochloric Acid. (Although I've heard a few people express some doubt about any real need for the latter. You could probably start a whole new thread on whether or not PH control is all that inportant.)

OK, crew. Am I missing anything?

Whaddya' think?

[JouMasep]

Regarding bonding, selection of materials inert enough, etc.

Firstly, many of us use polyolefin (polyprop, polyethylene) vessels.
As pointed out, there are certain very special bonding agents and primers to bond these materials –but they are expensive, hard to come by and in all likelihood not resistant to chlorine.

One of the big advantages of using polyolefin vessels’ is that most of them are quite resistant to all kinds of chemicals and most of them are quite resistant to chlorine over very long periods.

Vessels of all sorts and machinable stock is easy to get, and also very cheap –unlike Teflon.

So how do we glue it?

First what does NOT work.
-Any type of silicone product.
-Epoxy
-cyanoacrylates
-just about anything else, except the aforementioned special goodies that I have never tried or even seen.
And also excepting hot glue!

Hot glue actually sticks –the reason for this is the similarity of the molecular structures of the polyolefins and the components in the hot glue – just as the old chemical adage “like dissolves like” goes, so does “like sticks to like” apply. Loosely: polar goodies will glue polar goodies; but unfortunately most bonding agents are more or less polar and our practical poly plastic is anything but polar!

So we are “stuck’ with hot glue –which sadly is not of great mechanical strength –nor is it quite as inert as the polyolefins themselves.

But it is cheap and plentiful, so if one uses a thick layer, one is covered for a long time. As said above, the surface becomes crumbly and opaque, but this crumbly layer will protect the glue underneath for months –or more!

Tip: the hotter the surfaces that need joining are, the better the bond. Use a HOT hair drier to preheat your plastics. (Or try even a heat gun at low setting)

Also, if the surface of exposed (to harsh chemicals) hot glue is non-planar, or otherwise amenable to “winding” a very good method exists to protect the hot glue.

First apply the glue, then wind PTFT tape around it with additional small dabs of glue, using a hairdryer at the same time. The excess glue will squeeze out as a result of the winding action and this will form a very resistant protective layer.

In fact PTFT can work wonders in combination with cyanoacrylate glue as well.

I once needed to get some kick-but cooling in a certain reaction vessel. My stainless steel cooling coil became quite pitted and I liked my coil otherwise; could not get a decent Teflon tube anyway. So I spent a happy time winding Teflon tape in conjunction with the super glue around my stainless coiled tube. A bit of work, but it lasted very nicely.

Tip: when working with cyano, have a small piece of thickish polyethylene bag to hold and finger- press or rub one’s work into place.

Now I imagine comments like “but no way cyano bonds to Teflon”.

True- but it works all the same. The reason is that the PTFT tape is rather porous, hence the winding forces a mechanical bond –not a true chemical gluing bond. I reckon the glue permeates somewhat into the Teflon’s open structure.

In the same vein, as pointed out above, it is possible to abrade a plastic surface and to use a glue that is in itself strictly speaking incompatible -but it is far from ideal and tends to peel or delaminate under the influence of chemicals, stress and temperature changes.

Lastly for strength, If you have a lathe and don’t mind a bit of work, one can always make up flanges and gaskets (with say polyolefin foam as gasket) and nuts and bolts -all made out of HDPE. This has lasted me forever and looks very classy too.

I have avoided rigid PVC myself, but I would like to learn if anyone actually had this working out well under prolonged exposure to chlorine –that particular plastic is very easy to bond of course.

[Bacon46]

I have avoided rigid PVC myself, but I would like to learn if anyone actually had this working out well under prolonged exposure to chlorine –that particular plastic is very easy to bond of course.

It depends on what you mean by prolonged?

I was curious as to what affect a chlorate cell would have on PVC as well.

I have had rigid PVC submerged in a running chlorate cell continuously for over a month. When I removed the pipe from the cell I rinsed it with clean water and allowed it to dry. Upon close visual inspection the only noticeable sign of deterioration was a very dull surface and a thin film of white powder that comes off on your hand. The corners of the fittings are still sharp and the glue joints have remained intact. So far I think it is performing well.
If there has been any contamination of the electrolyte it is not visually detectable with the naked eye. The electrolyte is very clear.

I will try preheating the pipe and applying Teflon tape to the hot glue. You have obviously done a good deal of experimentation in this area. :cool:

[Lewis]

I just received my MMO anode/Ti cathode in the mail. I set up a small cell for chlorate production with KCl today. I put the cell in a plastic toolbox in my yard, with wires running indoors to the power supply.

For obvious reasons (esp. during startup when Cl2 release is highest), the box needs to be retreated from right after opening it up. Thinking about investing in a lock for the box. :p

http://i282.photobucket.com/albums/kk278/orbital_Saucer/DSCN1248.jpg?t=1213464788

http://i282.photobucket.com/albums/kk278/orbital_Saucer/DSCN1249.jpg?t=1213465347

http://i282.photobucket.com/albums/kk278/orbital_Saucer/DSCN1253.jpg?t=1213465452

http://i282.photobucket.com/albums/kk278/orbital_Saucer/DSCN1254.jpg?t=1213465467

The cell operates at an even 50ºC, and just over 4v with a 20amp switching power supply. The cell is small - about 1200mL, so it really heats up once the power is flowing. I had the unpleasant surprise of being gassed WWI style last night when I added too concentrated a solution of HCl to the cell. Won't be doing that again.

At this point the only real issue is pH control. The test strips I've got on hand get bleached by the electrolyte instantly, and turn white/clear. It's impossible to get a reading this way. I suppose I'll have to find another way to easily check the acidity of the cell in the future.

[Bacon46]

That setup should work well. I couldn’t determine the current output of your power supply from the pictures but KClO3 should be precipitating in no time, just harvest, clean and re-crystallize and you’re good to go.

Without a drip system of some kind the pH is going to be next to impossible to control. I wouldn’t even bother, just let it run and harvest the KClO3 as it precipitates. Lowering the pH by manually adding a splash of HCl won’t do much good; by the time you get back in house and parked in front of the TV it will be right back to where it was, probably around 8.5.

As shown in post 89 of this thread (http://www.roguesci.org/theforum/showpost.php?p=89622&postcount=89) One way to control the pH is to provide a slow continuous acid drip using an I.V. drip set attached to a plastic milk bottle that hangs above the cell. The flow rates of these I.V. drip sets vary from 10 drops per milliliter to 60 drops per milliliter. They have clamps that can be adjusted to control the drip rate by pinching the tube. The tighter you pinch the tube the more likely the system is to clog and stop dripping. Therefore it is best to purchase a drip set that requires more drops per milliliter of fluid dispensed, so that the use of the clamp is minimized. When using a drip system on a cell with a cover, there needs to be a vent large enough to allow evaporation to remove water fast enough to keep pace with the addition of the acid or the cell will overflow.

Should you choose to add a drip system, measuring the pH of the solution can be done with common pH paper. However, as you discovered, if the paper is simply dipped directly into the electrolyte the hypochlorite present will bleach the paper making a measurement impossible. This problem can be overcome by boiling a sample of the solution for 5 minutes to destroy the hypochlorite and measuring the pH of that sample.

In time you will know if your pH is okay by smell. If you sense any more than a slight smell of chlorine as you approach the cell the pH is too low and the chlorine gas is escaping. Either slow down the acid drip or dilute the HCl. If the acid drip is running and there is little to no smell of chlorine you are probably within the optimum range of 6.0 to 7.0.

Attempting to control pH in a chlorate cell can be troublesome. To see whether it was worth the trouble I ran an experiment using two identical 8 liter cells. One cell was run with an improvised pH control system (a drip system) and the other cell was run without any form of pH control. The cell without pH control realized a current efficiency of 29.98%, while the cell run with pH control realized a current efficiency of 59.67%. The production of the cell with pH control was almost double that of the cell run without it. I am going to repeat the experiment in the next week or so but I am confident the results will be the same. So, even though controlling the pH may be troublesome, it appears to be worth the effort.

To get the temperature up wrap the cell with some fiberglass (glass wool) building insulation. It works wonders.

I ran recently ran another experiment to determine the effects of chromates on current efficiency. The results were interesting but I need to repeat the experiment before I post the results. For now I will say that adding 2g/liter of Potassium Dichromate to the electrolyte is a good thing.:)

[Lewis]

Interesting. I may have to look into a drip system.

When you wish to "harvest" a batch of crystals, do you simply decant the solution and continue electrolysing, or go through the whole song/dance of boiling, filtering, etc?

After four days of running, the chlorate is piled deep at the cell bottom. The bottoms of the electrodes are beneath a layer of chlorate. This didn't seem like an issue to me, but I read earlier in this thread that a power supply was fried that way, and I didn't feel like risking my new investment.

I suppose an obvious solution to the problem would be getting a deeper cell, or perhaps using NaCl instead. (honestly, the only reason I didn't was not having much on hand)

Oh yeah, and the output is 20Amp. Picture was less blurry before it was scaled down.

[tranquillity]

To harvest my crystals i simply scoop them from the bottom of my cell using a net for a fish bowl. Then these crystals should be boiled, filtered and washed to remove impurities. The water you use for processing can be saturated with KCl and returned to the cell.

[Yafmot]

Hey, Bacon. A couple of things. First, on post # 210, you mentioned a plastic powder that melts at 565 C. That's over 1,000 F! I'd sure like to know about that stuff. So would NASA, DOD etc. The best polyimides only go up to around 600 F. If it could be electrostatically applied to dry fiber, you could make one Hell of a thermoplastic composite with it! (Provided the glass transition temperature is sufficiently high.) When the F-22 (then called the ATF, for Advanced Tactical Fighter) was under development back in the '80s, it was thought that 80% of the structural composites would be thermoplastics, with the balance being thernosets. The TPs would have been primarily PEEK (PolyEtherEtherKetone), which melts at about 800 F. Unfortunately, they found out that the T[sub]g is about half that, so they would be better off with a PI, Bismaleimide, or even a high temp Cyanate Ester or Epoxy. What's the name of this stuff and where can I get it?

What other acids can I use to keep my PH down? I have lots of Citric. Would the main issue be materials compatability?

Also, my infant Grandson was in the hospital with some bad stuff going on, and since he was released he has been receiving in-home care from a part-time nurse. one of the things left over was a programmable peristaltic pump for the IV. If it's like the others I've seen, it can be run off an external trigger, say, from a PH monitor/alarm or a level sensor. My Daughter In Law said I could have it when they're done with it. Ideas?

Also, I was taking a look at your slide show on post# 207, and it occurred to me that I've seen two piece PVC grommets that thread together to clamp & seal pipes feeding through, say, the wall of a hot tub or pool. I've also seen a version for marine applications. O-rings handle the sealing chores, though you might have to upgrade to Teflon seals or similar. Seems a whole lot less involved than all that glue-globbing.

By the way, concerning my piece on composite rocket motor casings, as well as part two of my thread on advanced materials, are going to have to wait until after the dust settles from all the shit swirling around me. In addition to the above-mentioned problem with my Grandson (and family ALWAYS comes first), there are various & sundry pitbulls that I've got to pry off my ass (metaphorically speaking). That, and a couple of writing assignments for a technical publication that I've had to do a lot of research for. (Hey, a guy's gotta' eat.)

So I've had to punt on those other two projects. But rest assured, they will be completed.

As for the other stuff, whaddaya' think?

[Bacon46]

I am sorry to hear about your grandson. I hope he has a speedy recovery.

I would love to know exactly what type of material the plastic is as well. It is known in the printing industry as thermography powder or thermography plastic. It is quite common so I am sure NASA or the DOD would be using it if it was applicable. It can probably be ordered over the internet or you can PM me with the shipping information and I will send you a pound to play with. It is not very chemical resistant. I wound up filtering it out of the electrolyte.

I don’t know what affect citric acid would have in a chlorate cell. If you live in the US I would just buy some HCl in the pool supplies section of your hardware store. It’s cheap and one gallon makes over 30 gallons of 3%.

I am always looking for a better, chemical resistant ways to seal penetrations in chlorate cells and other apparatus. I have thought about those grommets but haven’t found any suitable yet.

[Alexires]

I don't think Citric would be good. By adding HCl, it dissociates into H+ and Cl- ions, thus lowering the pH as well as supplying Chlorine that the system might be losing. If you added Citric, it would react (I would assume) with the alkali metal (in this case Na) and use it up (forming Sodium Citrate which would be a bitch to get out of solution), so it would push the equilibrium from the Sodium Chlorate side towards the reactants side, resulting in loss of product.

Find some HCl if you can. If you can't then you might just have to do without.

[Pb_Canadian]

I had the unpleasant surprise of being gassed WWI style last night when I added too concentrated a solution of HCl to the cell. Won't be doing that again.

The exact same thing happened to me about 3 weeks ago. What’s even worse is I lost about 800g of chlorate - into the wind as deadly Chlorine dioxide. (bought a respirator and a gas cartage to prevent anything like this from corroding my lungs).

For pH reading, buy a cheap electronic pH tester works like a charm. (check eBay if all else fails).

Question –

What do you use to deliver current to you cell. I’ve gone through 2 computer power supplies already, and the don’t even work half the time.

[Yafmot]

I've just traded a kilo of Ammonium Persulfate straight across for a really nice Astec switching supply (>$700 retail) new in box. It's not exactly what I want, but what the hell is when you're horse trading? In case anyone is interested, it's a model ALS304C-1003. It's been discontinued, but there's tech support available from Emerson, who have apparently bought Astec.

The main output is 6VDC @ 40 Amps. It seems to me that if I space the electrodes far enough apart, I can control the current. As far as anode erosion goes, I've got 60 sq. in. of Pt clad Nb to work with, so current density isn't that much to worry about, at least in terms of degredation.

As for the other outputs, It's got 3 channels of 12VDC @ 5 amps, but they can be ganged in parallel to give the same voltage @ 15 amps. There are three trimmer pots, one for each secondary channel, and these have to be matched to ensure that the infernal contraption doesn't have to wrestle with itself. This should be satisfactory for the Perchlorate stage of the operation.

I'm going to check out a few pool supply shops and a boatyard or two (I worked as a marine mechanic a lot in my younger days), and shortly should have more info on seals, grommets or, as the nice lady at one of the pool shops I called referred to them, bushings. I also had another Idea; larger autoclaves used for composites processing have a circulating fan inside, but the motor has to be outside the vessel due to thermal considerations. The passthrough has to both contain the pressure (up to around 150 PSI), but has to function as a bearing as well. If I can find one made of a good grade of stainless, I was thinking about using one for a stirring device of some sort. I saw an interesting little item in the paint department at Home Depot. It had a "squirrel cage) impeller, like in a blower, attatched to the end of a 3/8" rod about two feet long. Just sticking a drill motor on it a couple times a day should provide sufficient agitation. To keep it out of the "mud," just use a drill stop. I seem to recall painted and bare metal versions. The former might present contamination problems, but the bare one could be protected by grounding it to the cathode when not in use.

I'll PM you, Bacon, as I'm very interested in playing with some of this plastic powder. I also have a friend with a powder coating setup, and it may be good for that, in some applications.

Let me know if I'm full of shit on any of this stuff. I'm rarin' to go, and I'd love to have some chlorate of my very own manufacture by the time the 4th rolls around.

Whaddaya' think?