Making Chlorates

[Flake2m]

I came across this chemical equation, when I was reading a book on halogens.
3Cl2(g) + 6NaOH(aq) --> 2NaClO3 + 3H2 + 5NaCl

This is an equation for the synthesis of sodium chlorate. This probaly won't be that useful to people that can buy the stuff, but where I live (Australia) in the end it is easier to make this stuff then buy it and have to practically answer questions at gunpoint :mad: . You could of course subsitute sodium for Potassium or any other metal.

This is an equation for Chlorates systhesis, how would someone go about synthesising Perchlorates (without perchloric acid)?

[Hvoroba]

This is a rather old and dangerous method because chlorine is involved. I would rather buy some good old Sodium Hypochlorite and boil some in my mom's favourite pot.

[Bitter]

It's crap, apparently. The chlorate yield is only about 10%, the rest just becomes a mixture of sodium chloride and water. The electrolytic method is said to be better.

<a href="http://www.poortour.com/build/pyrotechnics/kclox.html" target="_blank">Have a look at this</a> .

[Flake2m]

This method on chlorate and perchlorate production is very intresting but too expensive for someone like me to afford :( at the moment.
I suppose I will have come prepared when I want to buy some potassium Perchlorate.
I agree with you on the yield of making chlorates. You get 2 moles of chlorates for every 5 moles of chlorides formed, and this is not good.

[da man]

Flake2m, i live in Australia, and i don't think there is a big problem buying potassium chlorate/perchlorate legally, but i have never bought (even though i've wanted to), because it is incredibly expensive, like over $60 for 500g of potassium chlorate, and over $80 for 500g of potassium perchlorate. Do you know of a place that sells it cheaper?

[SATANIC]

why would you buy it at that much?? where did you get that price anyway?

i've been going to try the electrolitic mehtod for a while now, the only thing i really need is the potassium salt to convert NaClO3 to the KClO3. I can't find the salt substitute at ANY health stores, and i' not wasting KNO3. I think tho you can get Potassium salts as fertilisers cheap. I checked, but the only one i saw the other day was potassium sulphate, so i'll have to find something different......

otherwise, i'll try to just make the NaClO3. For the cost of a large bottle of table salt, you can't go wrong. :)

[vulture]

Well, if you're in for a challenge you could try my experimental method i've worked out, but you need permanganate. (It would suck major ***** if you couldn't even get that!)

Anyways get some sodiumhypochlorite, phosphoric acid and potassiumpermanganate.

3NaClO + 6KMnO4 + 2H3PO4 -&gt; 3NaClO3 + 6MnO2 + 2K3PO4 + 3H2O

MnO2 will fall out of the solution, but the problem is that K3PO4 is quite soluble.

I haven't tried this myself, but you can give it a shot if you're desperate.

<small>[ July 05, 2002, 04:35 AM: Message edited by: vulture ]</small>

[da man]

if that reaction did work, the manganese dioxide would precipitate out (as you said), then you could add a saturated solution of potassium chloride to precipitate potassium chlorate, which isn't very water soluable.

[vulture]

Indeed! Hadn't thought of that... :rolleyes: :o
And a little warning for all, don't use HCl or H2SO4! With HCl you'll be suffocating in the chlorine gas and with H2SO4 the reaction will work, but can easily get out of control or even become explosive.

[blazter]

if you can get sodium hypochlorite than why not just boil it down and add KCl as the method described on the chlorate page. this seems much easier to me, and may even require less elbow grease than going the KMnO4 route. with some research and work ive calculated that it would cost about 7$ to produce a pound of KClO3 (if your using 5.25% and getting it for about a dollar a gallon, and your KCl is really cheap, as in water softener salt) although it is rather tedious to boil that much bleach its fairly cheap and uses all OTC chems.

[da man]

blazter, i've tried the sodium hypochlorite method, and from a whole litre of bleach, i got about 2 or 3g! It gives incredibly bad yields!
I've tried the electrolysis method to, its alot of work, it takes a couple of days of electrolysing to get 100g!
So i think that if this method of vultures did work it would be a very quick and easy method with good yields. I wonder if another acid could be used like HNO3 or something (i just don't want to have to buy phosphoric acid, when this is all im going to use it for)?
Does anyone who have the chems want to try this? :)

[Flake2m]

After some research

I think the answer to getting better yields of KClO3 or KClO4 is the way you design the Cell. I would suggest using a transformer that has a high current output. I would also use a large volume of saturated solution (about 500ml) at a current of about 10 amps, so there is more solution to increase the yield (though not the efficenty).

Da Man, you might be able to get more sodium hypochlorite by using different brands of bleach, look on the label for the % it contains. Pool chlorinator will most probally contain more hypochlorite than bleach.

From looking at the website that was linked in this thread. It may be possible to make some hypochlorite with the Cell. In theory you could use NaCl or KCl to create hypochlorites, then convert the hypochlorates into chlorates and perchlorates by bubbling the exhaust chlorine through the solution.

[vulture]

I would use phosphoric acid because strong acids tend to show nasty reactions with KMnO4. H2SO4 forms highly unstable and explosive Mn2O7, while when using HCl you'll get poisoned by the chlorine gas. I don't know what would happen with HNO3, but I think it will be somewhat the same as H2SO4.
Organic acids will very likely get destroyed by the KMnO4.

EDIT: BTW, if you're lucky, the reaction might also produce some KClO4...

<small>[ July 06, 2002, 02:26 PM: Message edited by: vulture ]</small>

[firebreether]

Shit, i wouldnt mind 100 g in a couple days, thats not so bad considering how cheap it is. I still need to find suitable graphite electrodes. ONe reason is I haven't found much, mayeb because i haven't looked much. Oh well, i did look for some welding electrodes (or whatever they are) but i havent found an even half way decent welding shop nearby

[inferno]

Hahaha, Americans, chems here are usually about twice to 5 times as much as they cost for you. KClO3 and KClO4 do cost that much, mainly because the only way to obtain them is to buy technical grade and other high grade chems that are purified to 99.999% for lab use, which makes the cost skyrocket..

And KCl can be bought at chemists or health stores, ive seen it there. If you cant find it, tell them something about your cholesterol and ask them to order some in, it wont cost anything to order it in, as they buy from those places anyway, it only costs them to buy the actual product.

[vulture]

KCl won't help with cholesterol problems! :rolleyes: It's given as a substitute for NaCl because Na+ ions increase blood pressure, nerval transmission and residue build up in blood vessels, thereby increasing the stress on the heart.

[blazter]

using just generic bleach, that only has NaOCl listed in the active ingredents list (Snoee brand) i have been able to get yeilds of around 45g from 1.5L of bleach and about 56g of KCl. i have heard that if the bleach contains excessive amounts of NaOH it will decompose the NaClO3. i intend to try pool chlorination tablets in the future, as that would require much less boiling time (it takes about 2hr to boil down 1.5L!). from what ive read you just need to boil the ground tablets untill they stop foaming, and then add the KCl to end up with KClO3.

[vulture]

I've made my own PbO2 electrode today by electrolysing Pb in a dilute H2SO4 solution. The only problem is the PbO2 layer wears off very easy. I think I'm going to try to electrolyse an aluminium or iron electrode in dilute H2SO4.
This is done by connecting the electrode that needs to be oxidized to the positive baterry pole (in the cell it's the anode). In the case of Al the Al2O3 layer will be thickened and it is known that the oxide layer sticks to the metal very well.

[Alchemist]

Hello all,

In the USA (maybe other countries too!), Potassium Permanganate (KMNO4) is on the DEA's list. Also it is costly as the Chlorate is
if you can buy it. I do like the idea though. Has anyone ever converted MnO2, back to KMNO4? That would help!

Also if you use pool chlorine you do get better yeilds. Make sure you get Calcium Hypochlorite and NOT the organic Chloride!

The 3Cl2(g) + 6NaOH(aq) --&gt; 2NaClO3 + 3H2 + 5NaCl also does work ok, but as stated there is the Chlorine to deal with. The important thing is to have a well saturated solution of Sodium Hydroxide and it must remain HOT!

On the electrolitic method has anyone tried just Lead? I am setting up a cell this week end and am just going to the stanless steel, or maybe one of steel and Lead/PBO2 electrode. I am going to use a discarded computer power supply. 5 volts at 25 amps or 12 volts at 10 amps. I am going to use Potassium Chloride bought from a Agriculturial supplier.

[kingspaz]

i used graphite electrodes when i did it. i bought them from an art shop. sold as graphite sticks. like pencils but instead of wood they are solid graphite.

[Alchemist]

kingspaz,

What are the dementions of those graphite sticks. Also what was your yeild? Thanks!!!

[megalomania]

Alchemist, how exactly have you configured your computer power supply to do an electrolysis? I happen to have one laying around that I would like to put to work instead since my current battery charger is at work on another electrolysis.

[kingspaz]

Alchemist, i can't remember the yields from when i did it as it was such a long time ago (before i found the forum i believe). the graphite sticks have like a plastic varnish over then which is easily removed with a knife. they are about 150mm in length and about 7mm in diameter. they also come in different grades like pencils do. because of this i would expext HB graphite sticks to be best for electrodes as they are harder than the 8B ones i'm buying for the KNO2 synth. the higher the B grade the softer the graphite. eg, 4B is softer than 2B which is softer than B.

[vulture]

You can't use straight lead to convert KCl to KClO3 because the lead will get attacked by the chlorine and form PbCl2. How did you make your PbO2 electrode Alchemist?

BTW, if you make PbO2 by electrolysis of lead in dilute H2SO4, use no voltage above 2,3V. Higher voltage will cause gas production which weakens the oxide layer severely.

[Alchemist]

Hello all,

As for the computer power supply you must find the two pins that need to be shorted together to get the supply turned on. Look on the internet for pc supply wiring diagrams. If you can NOT find one I'll e-mail the one I found. Also some of these regulate current via other wires. I have not delt with these wires as yet. As stated above I am just for the first time setting this up this week end!

As for the PbO2 I used battery acid (H2SO4) and two 1.5 volt cells in series for a few days. Then I let them back in the HOT (98degree) sun for a few more days.

That's it so far...................

[blazter]

i finally got around to boiling some "HTH pool shock" (68% calcium hypochlorite) and the yeilds are MUCH better :) . using the procedure listed on Wouter Visser's chlorate page (which i doubled) i boiled 250g of pool shock to about 500ml water. When it says that it foams... it really foams up. I had to add it in small quantities as described in the procedure and i got impatient at the end and dumped a fairly large quantity in... i beleive that it spewed out a large amount of chlorine out because i could smell it about 20 feet away from where it was boiling. Next time i need to find a GLASS stirring rod as the piece of wood i was using started to dissolve. Filtering out the calcium chloride was a serious pain in the ass because it seemed to form a white gunk that took forever to filter... and even then i never really got a clear solution. it was also necessary to add more water along the way to make up for boiled off water and to help the layer of sludge separate from the liquid when filtering. BUT... the good news is that all this yeilded ~130g of KClO3! probably not of the highest purity as my flame test showed that there was probably some calcium salts still present and i had to cook it in the oven to fully get it dry. also the crystal type that formed was of the "cactus needle" type described on Visser's page, whereas during the bleach process i always got the "flat plates" type.

[kingspaz]

if you had to cook it in an oven it will have considerable impurities!
KClO3 dries easily in the air even here in the UK when washed clean of hygroscopic salts.

[blazter]

indeed there do seem to be significant contaminates in the pool shock batch. H3 made with it burns very slow and leave behind a large chunk of ash. i've been looking for some temperature/water solubility curves for calcium chloride and calcium chlorate and have been unable to find them. the best i can come up with is that calcium chloride is "moderatly soluable" and calcium chlorate is deliquescent which i guess would imply a high solbility. it would be nice to know of some sort of solvent that dissolves only KClO3 and not the calcium chloride which im assuming is contaminating my product. i suppose i could simply do a recrystalization as Visser's page suggests but it seems sort of wasteful to me. anyone have any better ideas on how to purify the product?

P.S -- i have a table that lists temperature/solubiliy of nifty compounds like NH3, KClO3, NaCl, KCl, NH4Cl, KNO3, NaNO3 and a couple of others. i got it from my H.S chem class... at least i got something worthwhile out of it :)

[da man]

Damn, i must hav really bad luck. I followed exactly the procedure for making chlorates from calcium hypochlorite from Wouter Visser's page (except i didn't double the amounts) and i obly got 9g!! Which was also very impure.
I've tried so many procedures for making chlorates and i also get terrible yields!

[kingspaz]

blazter, KClO3 isn't significantly soluble in cold water. simply place all your impure crystals on a cotton cloth and pull all the corners and edges towards the centre making like a sack with the KClO3 in the centre. then dunk this in cold water 2 or 3 times and then re-open it and leave it to dry. you should notice the mass of the crystals will drop because all the impurities will be removed. every dunk should last only a second. that way only a very small amount (if any) of KClO3 will be dissolved.

[blazter]

thanks for the idea :) i've now got some crystal drying now, and its a LOT less than it was before although it seems to be drying better. come to think of it i probably should have washed it like that to begin with...

[frogfot]

About electrolysis method..
I've been searching for graphite rods in about a year now, with no results. Been in a store yesterday where they sell painting thingys, found coal pencils, they had only one soft type which is usual coal, is weighted absolutely nothing ..well im dissapointed as usual.
I have however thoat about another ways to approach this problem:
The point of big anodes is to maintain low current dencity (40-80mA on 1cm2), so that when chlorine develops at anode it wouldn't form big bubbles and would have time to react with solution.. right?
Here i wonder if theres some other simple ways to devide those chlorine bubbles, if i decide to use high current dencity. Maby if i coat anode with glass fiber, then big chlorine bubbles will devide themselves into small when passing this glass fiber...
Or, maby theres a way to fill a bag with graphite powder and use it as electrode.. Bag should be chlorine resistant and let it through...
Have anybody tryed something of that?
Those thoats have tortured me for many month...

[rjche]

motion picture projectors use .25 inch by 12 inch copper coated carbon electrodes. Some have metallic oxides in core to correct arc
color.

Gouging rods for welders were half inch by 13 inch graphite rods used to blow holes in steel rather than drill it. Not used much now. May find a welding supply house with some unsold ones on the shelf for cheap.

lead dioxide plates are the brown ones in car batteries. Once thought of using a car battery as a 6 cell continuous chlorate producer, but one fellow thought the plates would be eroded quickly. Never tried it.

punch a small hole between cells, and pump solution through all 6 cells, to build up chlorate in external tank of solution. 6 times cell voltage would be easier to feed than single low voltage cell. Losses would keep temp where it ought be. Adjust current to keep proper reaction temp. Fluid cooling in external tank between cycles would allow greater cell current than otherwise.

[firebreether]

I thought the low current density helped to keep the anode erosion down. If it was to help all the Cl2 to react, or if you are having problems with Cl2 escaping from the cell, you could probably put both electrode horizontally, with the anode under the cathode, that way the chlorine bubbles up through the part of the soln. where it is most basic, so it reacts better. Just a thought.

[frogfot]

Well, i actually did, i used graphite rods from carbon-zink battery 4,5cm length 0,6cm in diameter. Anode under cathode like you say, at about 3A there was about 2mm bubbles evolving... Very stinky even after 1sec of operation. Cell length was also pretty big, 10cm.

[firebreether]

Try using more volume of liquid for the cell to help the Cl2 dissolve then, also maybe try changing the spacing of the electrodes. The way I see it is if the anode is closer to the cathode, the Cl2 gas will flow straight up to where the OH- is being formed to react better, instead of floating up around it and not reacting. Don't knwo if that will help. The biggest thing though, make the cell bigger. Wouter Visser says about 2 amps per 100 ml, maybe try less, around 1 or less, however each run will take longer(but you get more back).

[David 314]

I'm interested in producing large quantities of chlorates (read: many pounds), and if I'm using a corrosion-free anode such as platinum coated with an oxide, is an arc welder set on low power a good DC power source? I have one laying around, rated ~4V at 3 - 60 A adjustable.

David

[Jhonbus]

Sounds OK to me, but if you run it at 60 amps then you'll have to start worrying about what to do with those waste gases...

[Anthony]

You won't be passing 60A at 4v! :D Except into a dead short. You sure that's not a typo?

The only other concern is that welders aren't intended for continuous duty. But since you wouldn't be running it at full load it should be ok.

[vulture]

It could be 60A, since it's used for welding, but I wouldn't do that! Your wires will simply vaporize and you'll have a large steam explosion + a nice bang from the hot Cl2 + H2 -&gt; 2HCl reacting with eachother, after which you will be breathing hot HCl gas.... have fun!

[rikkitikkitavi]

I have had a 5V, 200 A computer (not PC:) supply that I unfortunately fried by forgetting to alter the power in setting from 110=&gt; 220 V !
that created an interesting effect...

so I never got the chance to do some serious chlorate production experiments.

my point is that low voltage , high amp powersupplies are out there , if you are lucky you could get one for free as surplus. Even a normal 250W PC-powersupply puts out 25A@5V , which could be sufficent in you are patient.

using 5A/mm2 copper wiring is sufficient. 60 A isnt that much really.

Welders can be run constantly , but at lower rating than normal- a 100 A welder can probably put out around 30 A continously. The more expensive, the more current at constant load.
But most welders are AC, you need one that outputs DC through a recitifier.
/rickard

<small>[ September 04, 2002, 03:48 PM: Message edited by: rikkitikkitavi ]</small>

[Anthony]

My point was that I didn't believe the current rating, in fact 60A really isn't that much for a welder. But I didn't believe the voltage rating. Most welders I've seen are at least 48v even for small ones.

Water, even loaded with salt offers resistance and 4v isn't going to enough to overcome that resistance and allow 60A to flow.

Using high currents, you are going to *have* to use cooling for your cell. I made a small cell from a jam jar and at &lt;8A it soon bcame too hot to hold.

[rikkitikkitavi]

a slight misunderstaning from my side.

hmm, I have been to a clorine-NaOH plant where each cell was 2,5 V,20000A. You can see the cells as a resistance, thus making the anode-cathode large surface enough lowers the resistance enough.

But how big? that is the question. For a small jar-size cell it would be impossible to push 60 A from 4V, true.

But then use a bigger jar.

welders normally dont run at 48V, when the arc is light voltage is about 15-30V, zero-current voltage is about 48V and up(limited to the threashold of high voltage-standards ) to easy lighting the arc when striking the electrodes.

/rickard

<small>[ September 05, 2002, 11:30 AM: Message edited by: rikkitikkitavi ]</small>

[Anthony]

I must say, 2.5v does seem awufully low, but can't argue with success :)

Yeah, obviously the voltage from the welder will drop with load. The specs I read were probably measured at open circuit.

[CommonScientist]

Would tungsten work as an electrode or would it just oxidise. I am asking this because I have an aboundance of it. 3/32" x 6" rods. I also have 1/16" x 6" rods. They make them that are 1/4" x 12" for welding thick metals together, but these cost like $10 USD each.

I have a r/c car battery charger but I doubt it will transform enough power.
120VAC, .095A ----> 11.5VDC, 1.05VA.

That is baby shit compared to your power supplies.

[Marvin]

Tungsten has very little resistance to oxidation, which is why welding has to be done in an inert gas. It will be consumed by hydrogen peroxide as reported on another forum. Quite surprising considering and this would indicate its a lousey electrode material for electrolysis.

[CommonScientist]

Oh I see now. Its a pity since I kinda have an aboundance of it.

Maybe I could go to a junkyard, get some catylitic converters, extract the platinum, smelt it, and form it into a rod or a plate. But I do not have the resources to be successful in doing that.

[T_Pyro]

You might not get enough Pt to form a plate or rod out of it: for the production of chlorate, you require low current densities (<20 mA/cm2, IIRC) to be succesful. Instead, you could consider using the Pt obtained to plate some other metal substrate. Provided you have the tools to do so, I'd say that would be the safest bet.

Then there's always the GSLD electrodes- on Wouter's page, it's been stated that they actually last quite long, though I haven't tried them myself yet.

In this (http://www.roguesci.org/theforum/showthread.php?t=3753) thread, Vulture stated that Indium electrodes could also be used.

[Zeitgeist]

A quick note on PC power supplies:

Short the green wire to ground (black) to turn on a modern ATX supply.

Red wire is normally the 5V rail.

[vulture]

In this thread, Vulture stated that Indium electrodes could also be used.

That's a grave error of mine! I meant to say Iridium, which is a noble metal with similar properties to platinum. I mentioned it, because some of my sources claim it's being used for medial needles and high quality parker tips.

Iridium - Platinum alloys are also much more resistant than platinum alone, IIRC.

[T_Pyro]

Ah, well, I thought I'd almost solved my anode problems. Back to the drawing board, then, for me.

There's an interesting plan for the construction of lead dioxide anodes using cloth substrate described here (http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/leaddiox/cloth.html). It sounds interesting, but the electrical conductivity of such an anode would be quite poor, although you could get extremely low current densitities, allowing for high chemical efficiency. Another problem would be the presence of flakes of lead dioxide due to gradual disintegration of the anode.

More on lead dioxide anodes here (http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/leaddiox/leaddioxide.html).

To add Zeitgeist's note:
The yellow wire is for +12v, to be used once the resistance of the cell goes up. However, the 5v line is preferable, since it can supply greater power. (125W for 5v, 108 W for 12v for me)

[tmp]

I produce perchlorates in my 2 gallon cell. Chlorates are produced as an
intermediate step. Gouging rods work just fine for chlorates only. The high
erosion of graphite anodes in these cells occurs because either the
temperature of the cell exceeds 40 C(104 F) or the percentage of starting
chloride has fallen below 10% by weight(and perchlorate production begins).

I use a 6-volt, 15-amp, battery charger. It takes more time than say a
12-volt charger would but I have less anode erosion as a result. Also it
helps to soak the gouging rods in linseed oil for a couple of days to slow
down the erosion. Keep the rods far apart to keep the temperature down.
If you can get it, add 1 - 2 grams of potassium dichromate, potassium
persulphate, or sodium fluoride for each litre of chloride solution you start
out with. This greatly aids the efficiency of production. Water, of course,
will be lost due to heat and electrolysis so keep the cell level constant.
Use more chloride solution for this if you're only interested in producing
chlorates.

BTW, T_Pyro, I've seen that link before. It's an excellent website !
But if you can find gouging rods, they'll work great for chlorates and they're
generally pretty cheap. I'm still working on anode designs for perchlorates -
that is non-graphite anodes. Currently, I'm using either MnO2, PbO2, or
TiO2 for experimental anodes.

[sparkee]

Has anyboby tried Titaninum for the anode?? I'm completeing a clhorate run and for the first time have been able to keep it going for the amount of time required using Ti. If any one has some thoughts please share them.

[tmp]

Sparkee, I'm glad to hear that you're having luck with titanium as an anode.
I haven't produced any perchlorate in long time. Got more than enough right
now. The last time I used titanium I'm sure it had been alloyed with some
other metal because it eroded in my cell in about 3 minutes. I have secured
some > 99% titanium tube. The next time I need perchlorate I'll post again
and let you know how it turns out. I'm sticking with my 6 volt/15 amp
battery charger for this purpose as it does a great job. The gouging rods
are still good for making just the chlorate. :D

[sparkee]

TMP, Thank's for the encouragement this has to be the most frustrating chemical I have yet to try to manufacture. I have yet to use the carbon rods wanting instead to try the perclhorate instead of chlorate. I may still try it just because I think I can....

[tmp]

Sparkee, I forgot to ask. What were your yields using the titanium anode ?
I'd be interested to know because it would save me the trouble of using
anodes coated with PbO2/MnO2. Don't misunderstand, I still intend to try
these other types when I can find a suitable substrate that doesn't allow
these coatings to erode quickly. I know I can't "fire" MnO2 or PbO2 into a
porcelain substrate because the heat of the kiln is more than high enough to
cause decomposition. I'm thinking about creating a rod that uses a plastic
binder(dissolved in acetone of course) with MnO2 or PbO2, that could conduct
current, even if poorly, and have an extremely low level of erosion in the
environment which it would operate. Such an anode would be versatile to
say the least. What I really want is an anode I can completely submerge in
the cell to minimize the loss of chlorine during the electrolysis as it would
produce higher yields and reduce the presence of that irritating chlorine gas !
Even next to a fan in the window, some of that chlorine still gets in and
causes some minor respiratory problems. I don't have the luxury of an
outdoor shed.

[sparkee]

I'm not so sure that I have yeilded anything as of yet. I still want to try another test on what I came up with but I'm thinking that it's glorified salt! I'm an Electrician and not a Chemist so in some areas I'm over my head. While I was able to keep the Ti electrodes intact for some time they to eventually eroded. I believe that a lot of the problem was the power supply. I was unable to maintain a constant current. These fluctuations would "overheat" the cell or no heat at all. I have a couple of old pc power supplies and I may give them a try. Or not, that's a lot of work done to come up empty handed. Any tip's would be huge!

[tmp]

Sparkee, what was the nominal voltage/amperage you were running ? Some
fluctuations in current will occur especially when the cell heats up. Also, did
you notice the smell of chlorine or a bleach-like odor ? This would be an
indication that something was going on because the hypochlorite(bleach) is
usually produced as an intermediate compound.

[j_dmillar]

I've got some platinum wire, a few feet of maybe .6mm. I'm wondering, if I use it as an anode, how well will it stand up to corrosion? I know it will last longer than most, but will it still erode? I want to try making chlorates, but I don't want to waste my precious platinum :( .

My (quite old) version of Encyclopedia Brittanica has a pretty good article on electrolytic chlorate production, if anyone wants it I'd be happy to send it.

Oh one more thing, about titanium, just found this:
http://www.azom.com/details.asp?ArticleID=1225

I found it rather interesting, most of the time the moisture is the problem not the solution in chlorine gas!

[tmp]

My next experiment with anodes will involve mixing TiO2 with high
temperature porcelain and firing at cone 10 in a kiln. Wouter's page
mentions DSA anodes made with TiO2. I'm still waiting for my kiln
to arrive(Olympic model). I found the TiO2 pretty cheap at a local
pottery shop(and the porcelain of course). TiO2 melts at 1855 C so
I'm not worried about it decomposing because I haven't seen a kiln
that can fire that high. Wish me luck and I'll report back when I have
results.

BTW, j_dmillar, that article on titanium's resistance to chlorine was
interesting. I downloaded it for future reference.

[meselfs]

You don't suppose all the SiO2 and Al2O3 would make the resistivity something like 657548756467524657 Ohms/m?

[tmp]

I'll let you know when I make the rods. It's my hope that with a sufficient
amount of TiO2, the resistance won't be too high. There are many ways
to get this stuff in or on the rods. Obviously, MnO2 and PbO2 wouldn't work
because the high temperature of the kiln will decompose those compounds.

[meselfs]

Ok. I'm still having trouble seeing how it would work, but it's definitely worth a try...

It's funny, though, there's a boxful of MnO2 in the studio I attend. I wonder what it's used for... probably for local oxidization the same way silicon carbide is use for local reduction.

[tmp]

Another method that I never got around to was using a plastic, soluble in
acetone to bind the material together. Checking various websites for
resistance to things like chlorine, oxygen, hydroxides, hypochlorites, chlorates,
and perchlorates, the best I could come up with is Viton with PVC being a
close 2nd. Teflon would be perfect but requires diethylamine to dissolve it.

[tmp]

Meselfs, you have a box of MnO2 ? If you could find a suitable binder and
fashion it into a rod you may have a beautiful anode for producing chlorates
at the very least ! I bought MnO2 from the same pottery shop where I got
the TiO2. It was even cheaper than the TiO2 ! The problem I find with any
anode is corrosion. I would stick with the gouging rods(I have plenty of
them) if the damn things didn't corrode so rapidly. The problem isn't with the
chlorates per se, but with the perchlorates ! This is why my search
for the highly resistant anode continues. If you can bind up that MnO2 and
make it work for you, PLEASE share this info ! As soon as my kiln arrives and
I fire the TiO2 rods, I'll report back with rod resistance, corrosion rates, and
of course, yields. Even if the TiO2 rods don't work, I like ceramics and could
produce such things as crucibles and high temperature retorts, so the
money hasn't been wasted.

BTW, I found an arc welder supplier offering 1" gouging rods. WOW ! In the
past, my local supplier had the 3/8" rods as the largest.

[tmp]

Meselfs, you have a box of MnO2 ? If you could find a suitable binder and
fashion it into a rod you may have a beautiful anode for producing chlorates
at the very least ! I bought MnO2 from the same pottery shop where I got
the TiO2. It was even cheaper than the TiO2 ! The problem I find with any
anode is corrosion. I would stick with the gouging rods(I have plenty of
them) if the damn things didn't corrode so rapidly. The problem isn't with the
chlorates per se, but with the perchlorates ! This is why my search
for the highly resistant anode continues. If you can bind up that MnO2 and
make it work for you, PLEASE share this info ! As soon as my kiln arrives and
I fire the TiO2 rods, I'll report back with rod resistance, corrosion rates, and
of course, yields. Even if the TiO2 rods don't work, I like ceramics and could
produce such things as crucibles and high temperature retorts, so the
money hasn't been wasted.

BTW, I found an arc welder supplier offering 1" gouging rods. WOW ! In the
past, my local supplier had the 3/8" rods as the largest.

[tmp]

Meselfs, you have a box of MnO2 ? If you could find a suitable binder and
fashion it into a rod you may have a beautiful anode for producing chlorates
at the very least ! I bought MnO2 from the same pottery shop where I got
the TiO2. It was even cheaper than the TiO2 ! The problem I find with any
anode is corrosion. I would stick with the gouging rods(I have plenty of
them) if the damn things didn't corrode so rapidly. The problem isn't with the
chlorates per se, but with the perchlorates ! This is why my search
for the highly resistant anode continues. If you can bind up that MnO2 and
make it work for you, PLEASE share this info ! As soon as my kiln arrives and
I fire the TiO2 rods, I'll report back with rod resistance, corrosion rates, and
of course, yields. Even if the TiO2 rods don't work, I like ceramics and could
produce such things as crucibles and high temperature retorts, so the
money hasn't been wasted.

BTW, I found an arc welder supplier offering 1" gouging rods. WOW ! In the
past, my local supplier had the 3/8" rods as the largest.

[meselfs]

I might toy with that later. MnO2.

Currently, I'm most interested in catalytic converters. It's a ceramic honeycomb coated with a very small amount of platinum + rhodium. I recently salvaged a well used converter; I cleand it nicely but not too aggresively and checked the resistance. It was greater then 1 megohm... too much. I'm thinking a fresh converter (this one had 150000 km + on it) might possibly have near zero resistance...

New converters ain't that expensive, I thought ALL were 150$, but here on eBay some cheap one's are available, example (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7960480110&category=33629).

[meselfs]

I might toy with that later. MnO2.

Currently, I'm most interested in catalytic converters. It's a ceramic honeycomb coated with a very small amount of platinum + rhodium. I recently salvaged a well used converter; I cleand it nicely but not too aggresively and checked the resistance. It was greater then 1 megohm... too much. I'm thinking a fresh converter (this one had 150000 km + on it) might possibly have near zero resistance...

New converters ain't that expensive, I thought ALL were 150$, but here on eBay some cheap one's are available, example (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7960480110&category=33629).

[meselfs]

I might toy with that later. MnO2.

Currently, I'm most interested in catalytic converters. It's a ceramic honeycomb coated with a very small amount of platinum + rhodium. I recently salvaged a well used converter; I cleand it nicely but not too aggresively and checked the resistance. It was greater then 1 megohm... too much. I'm thinking a fresh converter (this one had 150000 km + on it) might possibly have near zero resistance...

New converters ain't that expensive, I thought ALL were 150$, but here on eBay some cheap one's are available, example (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7960480110&category=33629).

[Flake2m]

Actually the Catalytic converter idea is an intresting idea.
It might be worth looking into extracting the Platinium and Rhodium from the converter using aqua regia, then electroplating the Pt and Rh. I don't know if that will work, however since most catalytic converters have around 5 grams of of Pt/Rh in them a single converter is probaly enough for an anode, since you don't need much to coat it.

Actually this could work, however the oxymoron is that you'd need a material that could withstand aquaregia in the first place. Looks like we are back to square one. Maybe someone else can progress my train of thought further?

[Flake2m]

Actually the Catalytic converter idea is an intresting idea.
It might be worth looking into extracting the Platinium and Rhodium from the converter using aqua regia, then electroplating the Pt and Rh. I don't know if that will work, however since most catalytic converters have around 5 grams of of Pt/Rh in them a single converter is probaly enough for an anode, since you don't need much to coat it.

Actually this could work, however the oxymoron is that you'd need a material that could withstand aquaregia in the first place. Looks like we are back to square one. Maybe someone else can progress my train of thought further?

[Flake2m]

Actually the Catalytic converter idea is an intresting idea.
It might be worth looking into extracting the Platinium and Rhodium from the converter using aqua regia, then electroplating the Pt and Rh. I don't know if that will work, however since most catalytic converters have around 5 grams of of Pt/Rh in them a single converter is probaly enough for an anode, since you don't need much to coat it.

Actually this could work, however the oxymoron is that you'd need a material that could withstand aquaregia in the first place. Looks like we are back to square one. Maybe someone else can progress my train of thought further?

[meselfs]

Umm, glass. Glass holds up against aqua regia just fine.

I'd considered this, actually, extracting the platino-rhodium off the honeycomb, since like I said I have one already, but it's old. However, I'd like to try getting one of those 15$ converters first, it's worth it I think. I'm moderately busy now, else I would've experimented this months ago...

[meselfs]

Umm, glass. Glass holds up against aqua regia just fine.

I'd considered this, actually, extracting the platino-rhodium off the honeycomb, since like I said I have one already, but it's old. However, I'd like to try getting one of those 15$ converters first, it's worth it I think. I'm moderately busy now, else I would've experimented this months ago...

[meselfs]

Umm, glass. Glass holds up against aqua regia just fine.

I'd considered this, actually, extracting the platino-rhodium off the honeycomb, since like I said I have one already, but it's old. However, I'd like to try getting one of those 15$ converters first, it's worth it I think. I'm moderately busy now, else I would've experimented this months ago...

[tmp]

Finally, the goddam thing arrived - today ! I'd been been waiting almost
9 weeks ! Now is the time to form and "high" fire some test anodes. Can't
wait to report back ! :D

[tmp]

Finally, the goddam thing arrived - today ! I'd been been waiting almost
9 weeks ! Now is the time to form and "high" fire some test anodes. Can't
wait to report back ! :D

[tmp]

Finally, the goddam thing arrived - today ! I'd been been waiting almost
9 weeks ! Now is the time to form and "high" fire some test anodes. Can't
wait to report back ! :D

[Pb1]

Umm, glass. Glass holds up against aqua regia just fine.

He was referring to an electrode material, something that conducts electricity.

[Pb1]

Umm, glass. Glass holds up against aqua regia just fine.

He was referring to an electrode material, something that conducts electricity.

[Pb1]

Umm, glass. Glass holds up against aqua regia just fine.

He was referring to an electrode material, something that conducts electricity.

[meselfs]

Here's what I'd do:

Crush the honeycomb, pour into the aqua regia.
Apply heat.
Strain.
Boil off acid.
Mix with NaOH solution to make a chloroplatinate.
Electroplate onto any metal of your choice.
Coat any connections to your new electrode with epoxy. Do not use JBWeld (or was it JBQuick? Or both?), it contains metal filling.

Congrats on getting a kiln, tmp. Jeez how I wish I had my own studio...

[meselfs]

Here's what I'd do:

Crush the honeycomb, pour into the aqua regia.
Apply heat.
Strain.
Boil off acid.
Mix with NaOH solution to make a chloroplatinate.
Electroplate onto any metal of your choice.
Coat any connections to your new electrode with epoxy. Do not use JBWeld (or was it JBQuick? Or both?), it contains metal filling.

Congrats on getting a kiln, tmp. Jeez how I wish I had my own studio...

[meselfs]

Here's what I'd do:

Crush the honeycomb, pour into the aqua regia.
Apply heat.
Strain.
Boil off acid.
Mix with NaOH solution to make a chloroplatinate.
Electroplate onto any metal of your choice.
Coat any connections to your new electrode with epoxy. Do not use JBWeld (or was it JBQuick? Or both?), it contains metal filling.

Congrats on getting a kiln, tmp. Jeez how I wish I had my own studio...

[meselfs]

While operating my mill, an idea hit me: what about titanium nitride? It's a very hard (Rc 83) gold colored substance used to coat drills, mills, & such. If TiO2 works, I figure it's likely this'll work too. I don't have a decent poewr supply on me atm, I'll try this later.

The coating is often around 0.001" thick, FYI. I sincerely apologize for not being metric here.

[meselfs]

While operating my mill, an idea hit me: what about titanium nitride? It's a very hard (Rc 83) gold colored substance used to coat drills, mills, & such. If TiO2 works, I figure it's likely this'll work too. I don't have a decent poewr supply on me atm, I'll try this later.

The coating is often around 0.001" thick, FYI. I sincerely apologize for not being metric here.

[atmosphere1]

I use a mixed metal oxide (iridium)coated Ti anode. This type of anode is used professionaly for electrolysing sodiumchloride.
http://img.photobucket.com/albums/v301/atmosphere/IMG_0578.jpg
The cathode is made out of simple stainless steal .
I was able to maintain a clear solution all the way from chloride to perchlorate. After producing 2 pounds of sodiumperchlorate the anode looked completely unaffected.

I can get into detail about everything involved in making and running a cell like mine for chlorate/perchlorate production , and I will ,when people have questions .

Power supply : ring shaped transformator ,wich was adapted(at secundairy side) to get a lower voltage and more current . When the cell runs : 5,5 V and up to 30 A .

Cell : contains 2 liters of electrolyte and is made out of glass.

[meselfs]

Where in the world did you get that, and how much did it cost?


Btw, my TiN didn't work.

[atmosphere1]

There's a company here in holland that produces these type of anodes. I had to do some talking to be able to buy a smaller piece since normally they only sell large pieces to other company's.

I will post more information about thier complete anode line .

[FrankRizzo]

atm,

That little fellow looks like a salt water pool chlorinator anode :) Please post your technique.

[Ricky]

Potassium perchlorate is easy manufactured when 1 mol powdered potassium carbonate is stirred into 2 mol of 70% perchloric acid in a simple beaker. When the crystals are dryed they don`t have any remainders or impurities.
2 HClO4 + K2CO3 => 2 KClO4 + H2O + CO2
Does someone have infos to the perchloric acid manufacture from potassium perchlorate and concentrated H2SO4 without a vacuum distillation ?
KClO4 + H2SO4 => HClO4 + KHSO4
I belive it would work in somewhat dilute environment and a distillation with a oil bad, a distillation column and a sight stream of steam. The remainder of the water is than removed by heating up the mix above 101 °C.
200 g KClO4 per 142 g 98% H2SO4
HClO4 60 %, bp around 160 °C
HClO4 70 %, bp 198,7 °C

[nbk2000]

Oh...that's right...we've never heard of the 'nuetralize an acid with a base to get the desired salt' method.

Tell me, just where is it that you GET perchloric acid from in the first place, hmm?

:rolleyes:

[Ricky]

This technique is well known, vacuum distillation is safer and the acid is purer. Maybe the anhydrous acid will explode from temperature differences.
I belive a good equipment is adequate.

[c.Tech]

Distilling perchloric acid? Sounds like suicide.

Countless accidents have occurred with perchloric acid, some of which have been fatal.

Make it safer by exchanging the ions of different salts when possible.

Source: http://www.auburn.edu/administration/safety/crcperchloric.html
Number 7 recommended for reading.
Appendix 1: Some Accidents Involving Perchloric Acid

1. Explosions may occur when 72% perchloric acid is used to determine chromium in steel, apparently due to the
formation of mixtures of perchloric acid vapor and hydrogen. These vapor mixtures can be exploded by the catalytic
action of steelparticles.2
2. Two workers are reported to have dried 11,000 samples of alkali-washed hydro-carbon gas with magnesium
Perchlorate over a period of 7 years without accident. However, one sample containing butyl fluoride caused a
purplediscoloration of the magnesium Perchlorate, with the subsequent explosion of the latter.2
3 . A worker using magnesium Perchlorate to dry argon reported an explosion andwarned that warming and
contact with oxidizable substances should be avoided.2
4. An explosion was reported when anhydrous magnesium Perchlorate used indrying unsaturated hydrocarbons was
heated to 220'C.2
5 . An explosive reaction takes place between perchloric acid and bismuth or certainof its alloys, especially during
electrolytic polishing.2,5
6. Several explosions reported as having occurred during the determination ofpotassium as the Perchlorate are
probably attributable to heating in the presenceof concentrated perchloric acid and traces of alcohol. An incident
in a French laboratory is typical: an experienced worker in the course of a separation ofsodium and potassium
removed a platinum crucible containing a few decigramsof material and continued the heating on a small gas flame.
An explosion pulverized the crucible, a piece of platinum entering the eye of the chemist.7
7. A violent explosion took place in an exhaust duct from a laboratory hood inwhich perchloric acid solution was being
fumed over a gas plate. It blew outwindows, bulged the exterior walls, lifted the roof, and extensively
damagedequipment and supplies. Some time prior to the explosion, the hood had beenused for the analysis of
miscellaneous materials. The explosion apparentlyoriginated in deposits of perchloric acid and organic material in the
hood andduct.8
8. A chemist was drying alcohol off a small anode over a Bunsen burner in a hoodreserved for tests involving
perchloric acid. An explosion tore the exhaust ductfrom the hood, bent a portion of the ductwork near the fan,
and blew out many panes of window glass.8
9. An employee dropped a 7-pound (3.2 kg) bottle of perchloric acid solution ona concrete floor. The liquid was
taken up with sawdust and placed in a covered, metal waste can. Four hours later, a light explosion blew open
the hinged cover of the can. A flash fire opened three sprinklers which promptly extinguished the fire.8
10. A 7-pound bottle of perchloric acid solution broke while an employee wasunpacking a case containing three bottles.
The spilled acid instantly set the wood floor on fire, but it was put out quickly with a soda-acid extinguisher.8
11. At a malleable iron foundry, perchloric acid had been used for about 4 years inthe laboratory for the determination
of the silicon contents of iron samples. Acast iron, wash-sink drain at the bench used for this purpose had
corroded and the leaking acid had soaked into the wood flooring, which was later ignited whilea lead joint was
being poured. This fire was extinguished and part of the woodflooring was removed. Later in the day, at a point
slightly removed from the location of the first fire, a similar fire occurred when hot lead was again spilled.This time
the fire flashed with explosive violence into the exhaust hood and stackabove the workbench. Laboratory
equipment and records were wetted downextensively and damaged.
12. A stone table of a fume hood was patched with a glycerin cement and severalyears later, when the hood was being
removed, the table exploded when a worker struck the stone with a chisel. The hood had been used for digestions
with perchloric acid and, presumably, acid spills had not been properly cleaned up.9
13. A conventional chemical hood normally used for other chemical reactions, including distillation and ashing of organic
materials, was also used during the same time for perchloric acid digestion. During a routine ashing procedure, the
hot gases went up the 12-inch tubular transit exhaust duct and one of a series of explosions occurred that tore the
duct apart at several angles and on the horizontal runs.9
14. During routine maintenance involving partial dismantling of the exhaust blower on a perchloric acid ventilating
system, a detonation followed a light blow with a hammer on a chisel held against the fan at or near the seal
between the rear cover plate and the fan casing. The intensity of the explosion was such that it was heard 4 miles
away. Of the three employees in the vicinity, one sustained face lacerations and slight eye injury; the second
suffered loss of four fingers on one hand and possible loss of sight in one eye; the third was fatally injured with the
6-inch chisel entering below his left nostril and embedded in the brain.9
15. A 6-pound (2.7 kilograms) bottle of perchloric acid broke and ran over a fairly large area of a wooden laboratory
floor. It was cleaned up, but some ran down over wooden joists. Several years later a bottle of sulfuric acid was
spilled in this same location and fire broke out immediately in the floor and the joists.9
16. A chemist reached for a body of perchloric acid stored on a window sill above a steam radiator. The bottle struck
the radiator, broke, and the acid flowed over the hot coils. Within a few minutes the wooden floor beneath the
radiator burst into flame.9
17. An explosion occurred when an attempt was made to destroy benzyl celluloses by boiling with perchloric acid.11
18. An explosion occurred as anhydrous perchloric acid was being prepared via sulfuric acid dehydration and extraction
with methylene chloride when a stopper was removed from the separatory flask.14
19. A rat carcass was dissolved in nitric acid, the fat skimmed off, and perchloric acid added. The mixture was
heated to dryness and touched, setting off an explosion that cracked the fume hood and nearly blew out the sash.16
20. A perchlorate-doped polyacetylene film was prepared and stored under argon in a seated vessel. Two weeks later,
the film detonated when the vessel top was being removed. Earlier safety testing failed to show any reaction to flame
or impact.17
21. Perchlorate-doped polyacetylene samples combusted violently in the oxygen atmosphere of a Schoniger flask.18
22. An explosion occurred in a fume hood upon ether drying of a second crop of crystals of hexaminechromium (111)
perchloratethatwere washed with absolute ethanol and anhydrous diethylether. Following aspiration of the ether
wash, the ether damp filter cake was agitated with a glass stirring rod and the mass detonated.19
23. Perchlorate-doped, highly conducting polythiophene Pt-CIO, exhibits excellent ambient stability, but the film should
not be heated above 1000C. Touching an extremely dry Pt-CIO, film (kept in a desiccator over P20,) with
tweezers might cause an explosion of the film.20
24. Some samples of rare earth organic fluoride were re-ashed with perchloric, sulfuric, and nitric acid in I -liter
beakers. One of the beakers started foaming, turned yellow, and then exploded. The surface of the hot plate
was bent downward, and the imprint of the beaker was left in the metal surface of the hot plate by the force of the
explosion.1
25. Drying an acetonitrile adduct of neodymium Perchlorate at SO'C in vacuumapparently produces a compound that
can detonate on mechanical contact.21

[ETCS (Ret)]

Computer power supplies work very well for Chlorate/Perchlorate cells.

You may use the 5 volt output or, in the case of the newer ATX style supplies,
either the 5 volt or the 3.3 volt output as suits your needs.

With the older style PC/XT supplies have your "load" cell connected to the
power supply 5 volt output before you power it up.

With the newer ATX style power supplies have your "load" cell connected to
the power supply before you power it up, then on the 20 pin power connector
connect Pin 14 (PS-ON) a green wire, to Pin 15 (GND) a black wire, to get the
power supply to start up.

Leave those pins connected as long as you desire power to the "load"
and simply disconnect them to shut the supply down.

You can Google "ATX Power Connecter" to get a diagram of the 20 pin connector for future reference.

[Pots-O-Potash]

Has anyone here ever tried or heard about using silver or gold as a cell anode for chlorates and/or perchlorates.

I've had the idea for a while but haven't gotten a chance to try yet.(lack of time not materials, except gold)

[Bert]

Ag is far too reactive. Au might be a possibility, but as Pt is much more expensive than Au, I'd guess the commercial operations wouldn't be using Pt if it worked well.

[hydra]

Some years ago, I used a piece of carbide tooling for an electrode in a different process.

Have any of you tried this material yet for a perchlorate electrode?

I'm talking about solid carbide tooling....not "carbide-tipped" steel tools.

Carbides, Borides, and Nitrides, generally make pretty good 'inert' electrodes.

Of course, even "solid carbide" tooling is not 100% carbide. It consists of micro-fine powdered carbides sintered together with a 'binder'...usually cobalt metal. But cobalt itself is a fairly resistant metal...and the majority of the tool IS carbide, not cobalt...so even with some attack on the binder, it may still hang together a usefully long time.

Anyway, I thought I'd mention it as something worth trying once.

As I recall, I had a 3/8" solid carbide drill, jobbers-length, which had gotten its tip snapped off....had about 3" left. This electrode measured ZERO ohms end-to-end, by the way.

Not a high-area electrode by any means; but good enough for a test. If it works, the stuff is easy enough to come up with. You can usually scarf a pile of broken or worn-out carbide tooling at any machine shop for free.

"indexable carbide inserts" are worn out on a daily basis at any place doing production work. A guy could hang a handful of indexable carbide inserts on a resistant wire like platinum.

Worst case is, the carbide tool comes apart, and now you've got a nice cobalt plating solution to make catalysts with... :D


(speaking of wire, has anyone tried Nichrome as an electrode? Common electric heating element coils in dryers, toasters, etc.)


...and speaking of heating-elements, I haven't seen silicon carbide mentioned in these threads yet. That's a common electrical resistance-heating element material; as well as an abrasive....i.e., it's conductive.

As a heating-element, you gotta buy it. At least, I can't think of any OTC or junk source off the top of my head.

But as an abrasive, it's very common. Any tooling shop or Ace hardware, etc..

The 'green' grinding-wheels are silicon carbide. Might be worth putting one on the ohmmeter. Also, the 'black' sandpaper is normally silicon carbide. It'll say on the package.

Low conductivity can be made up for (to some extent) with large area...and this is a pretty cheap material...assuming it'll work at all.

I don't know how the conductivity of 'abrasive' material compares with that used for heating-elements, sorry.


tmp, you mentioned spreading the gouging-rods as far as possible to reduce heat. I think that will actually -maximize- heat. Assuming you're keeping the current the same, that is.

Heat is amps times volts. As you spread the rods, you are increasing the resistance of the current-path, and need to increase the cell-voltage in order to maintain the same current. The same amps, times a higher voltage, is a greater total power-input into the solution...i.e. more heat.

In most cases, increased cell-voltage causes accelerated electrode-erosion too; as well as higher gas-production. I think it would be best to run the electrodes as close as possible; and cool the bath, if it needs cooling.

Maybe set the container in a 2nd container with a slow feed of cold water running through it?

Also, regarding the MnO2....I don't think you need to 'fire' a ceramic binder with it. You only need to sinter the MnO2 to a -conductive- binder...which would happen just below its decomp. temp; presumably.

In any case, MnO2 itself is an insulator. You need to co-sinter it with carbon/graphite or something else, in order to get electronic conductivity. In dry-cells, they use about 90% carbon/ 10% graphite, roughly.

I think your idea of setting it in an organic binder is the easiest thing to try that has some chance of working. Again, it will need conductive material mixed in. On the other hand, that decomp-temp is easily high enough to carbonize most any organic binder. All you need to rig up is a controlled-atmosphere for your shiny new kiln. :D

Of course, the carbon may well come apart in the bath like graphite gouging-rod does....I don't know.

You could also try it without firing. If the plastic is thin enough, it will be ionically conductive to some extent. With the plastic solution made high in solvent, you should end up with a quite thin layer of insulator over the particles. And if I understand membrane-production correctly, you can make the plastic 'membrane' conductive by replacing the solvent with an aqueous solution of certain salts prior to the solvent drying.

Many common plastics can also be made 'functional', i.e. cationic-selective etc., by soaking the film in oleum. This will sulfonate the polymer.


Edit: to add two notes

1) above, I said you need to mix the MnO2 with conductive binder. But perhaps you are planning to 'fire' a monolayer of it to a conductive metal plate. I guess that would work; but with my own limited ceramicist skills, I wouldn't be confident of getting either a true monolayer, or a 100% pinhole-free 'seal'.

However, along the lines of firing it....you could try a "solder-glass" instead of a ceramic. I'm pretty sure there are solder-glasses which fuse below 450C. Also, check into glass 'frit'. These devitrify to a ceramic after firing. Not sure how low they make them, in terms of firing/fusing temps; but they use them to fuse together already-made glassware....so likely below the annealing temp of glass...which is in the 400-500C range.


2) Copier Toner. I think I read a mention of Magnetite in one of these ClO3 threads. I don't know if copier toner is magnetite, or something else; but it IS magnetic. Plus, it's already got both carbon and a nice plastic binder, all premixed for ya! :D

Might be worth fusing some onto a metal plate and seeing what kind of conductivity you get. Again, you might need to fire this material in controlled atmosphere to carbonize the plastic binder.


geez....edit again...to add a 3rd note/idea...lol...

3) those little japanese 'ceramic' space-heaters... Most of those use a heating element made from "electroconductive ceramic". I don't know whether they left the conductive surface exposed all over the element; or whether they put some sort of insulating-film everywhere except the lead-attachment points. But even if there's a film on there, a few minutes work with your trusty angle-grinder oughta fix that... :D

The resistance of the element -must- be fairly low...in order for it to work as a heater on 120vac. If you come across one of these heaters, it'd be worth putting ohmmeter probes on the ceramic and seeing what you can see. These may be quite resistant to the bath....