Chlorate Flash

[arm]

Im having some problems with my chlorate flash powder....

I recently knocked up a batch of Potassium Chlorate, prepared from Sodium Chlorate Weedkiller and Potassium Sulfate and then re-crystalized.

I tested the batch first in an H3 type mix and it functioned as expected (burned in a flash). However, when i tried a flash mix the results were, well, pretty lame. No better than my nitrate flash. In theory it should be better than a Perchlorate flash comp and burn with a whoomf. I tried a 2:1 and a 7:3 Chlorate:Al. The first was marginally better but still took about a second to burn. The aluminium i'm using is filler grade 200-325 mesh.

Any thoughts?

[arm]

I've been thinking about the fuel oxidizer ratio...

I calculated this stoiciometrically based on the following formula:

KClO3 + 2Al -> Al2O3 + KCl

So 1 mole of Potassium Chlorate reacts with two moles of Aluminium.

1mol KClO3 = 39 + 35.5 + (16 * 3) = 122.5 g
2mol Al = 27 * 2 = 54 g

Which is roughly:

30.5% Al
69.5% KClO3

Now, taking into account that flash mixes should be overfueled 2-3% and the fact that after only one recrystalisation my Chlorate is only about 97-98% pure this gives a 60/40 ratio approx. I've tried this ratio and it seems to be the best but its still not good. All the Chlorate flash mixes in the pfp involve sulfur which is a pretty retarded thing to add to a chlorate flash mix.

I'm lost as to whats wrong.....

[Haggis]

You said that the chlorate worked well in an H3 type mixture. This rules out the chlorate as the problem. You calculated the correct ratios and took into account purities. That was good. However, I believe your problem is the mesh of the aluminum powder. It is too coarse. From the mesh size, I would bet that the powder is shiny and bright. Good aluminum powder has a nice dark grey color to it. IMO the aluminum powder is your problem.

[frogfot]

You probably precipitated lots of sodium sulfate too. Look at it's solubility: in 100ml water; 5,02g at 0*C and 49,59g at 32,4*C.
Dunno why H3 worked well, maby it's pretty violent even with impure oxidiser..

[Arkangel]

Have you made any proper flash with this Al before?

I've had some very fine Al powder that's claimed to be something like that mesh size, but used in fibreglass work and I've had no success at all in getting it to burn except as a cast incendiary. J's page has a ratio for permanganate flash using such stuff, but I haven't tried it. If your Al is spherical not flake, then you're going to have trouble whatever the oxidiser, and as you say, sulphur with it too......hmmmmm:(

[arm]

Ok, im now wondering if the purity of my KClO3 is'nt part of the problem too. I was noting the crystal structure of a recent metathesis reaction with Potassium Sulfate and saw that the crystals were needle-like in form. A sure sign of an impure Chlorate (they should be mainly plate-like). Also, the compositions have a yellow sodium tinge to them when burnt, possibly due to Sodium Sulfate.

I'm wondering if the Potassium Sulfate double decomposition i'm performing is working as well as it should. Its based upon the follow reaction.

NaClO3(aq) + K2SO4(aq) -> KClO3(s) + Na2SO4(aq)

The solubilities of the salts are as follows (per 100g water @ 20 degrees C)

NaClO3.....98.8g
K2SO4.....11.1g
KClO3.....7.3g
NaSO4.....19.2g

Now, the Potassium Chlorate is still the least soluble in solution, but not by as much as it is when using Potassium Chloride to perorm the reaction.

Is the reaction usually performed with boiling water and then cooled, or, are the initial salts added to cold solvent?

[zaibatsu]

I use boiling water when I do it with KCl, and then chill in a fridge.

[arm]

Thats exactly the procedure i use, i wonder why its so impure. I;ve calculated the molar masses to be as follows:

NaClO3 = 106.5g (must be adjusted based on weekiller being 53% KClO3)
K2SO4 = 135g

And these are the masses to used since the stoiciometric ratio is 1:1

[Mr Cool]

Using un-sieved weedkiller never helps, it means you need a lot more water to get it all into solution.
But as you can see, the solubilities of K2SO4 and KClO3 aren't very different, meaning that it will be harder to get a pure product without recrystalisation.
Better to use KCl or KNO3 (Edit: if possible).

[vulture]

NaClO3(aq) + K2SO4(aq) -> KClO3(s) + Na2SO4(aq)


And these are the masses to used since the stoiciometric ratio is 1:1

Wrong!

2NaClO3 + K2SO4 --> 2KClO3 + Na2SO4 !!!!

If you look at your equation you will see that it is not mass balanced!!

That's why your chlorate doesn't work well!

[arm]

Ah yes, silly me. I should be hacked down for that one. Dont know how i missed that, probably a little distracted by the 10 exams i've got at uni next week. :(

[arm]

Yeah, I think the solubilities of KClO3 and Na2SO4 are really too close to each other to get a good product. I've used the corrected ratio's and the crystals that are forming still show strong signs of impure chlorate.

Another factor is that at low temperatures, KClO3 is less soluble than Na2SO4. But as the temp rises the solubilites quickly swap over.

Oh well back the KCl method and that damned LoSalt crap (unless i find suitable water softener).

By the way, has anyone tasted LoSalt - Salt substitute my ass! That stuff tastes like shit, I wouldnt put it on my friday night chips if someone payed me.

[frogfot]

The salt substituent that i use for extraction of chlorate contains 60% KCl, yours should be somewhere there too. I find it quite effective, it gives nearly same yield as with pure KCl but second recrystallisation is required anyway.

EDIT: Oh, some experimental data with salt substitute "Seltin", 40/60 NaCl/KCl
Electrolyte with NaClO3 were used, since concentration was approximated, I took KCl in clear excess:
500ml extracted with 150g Seltin gave 87g product
750ml extracted with 100g pure KCl gave 129g product

Thats nearly same, though first batch should contain slightly bigger ammount of NaCl. Both batches were combined and recrystollised which gave 181g (forgot to recrystollise them separate :rolleyes:)

[arm]

Ok, now this is perverse.

I tested my new batch of KClO3 made with K2SO4, again the crystals showed impure Chlorate but I decided to give it a shot. I used a 2:1 ratio of Chlorate:Al and this burned fairly slowly. I then gradually increased the amount of Al and the burn rate increased with each addition. The improvements stopped comming at around 1:2 Chlorate:Al!!!! What the hell is going on here? The stuff was bloody fast too, burning in a fierce white flash and a shower of sparks.

The only thing I can think of is the residual Na2SO4 from the double decomposition having an effect. The mix also contained +5% CaCO3.

I've looked on MSDS's and Sodium Sulfate is claimed to be an explosion hazard with aluminium. Although Data Sheet Writers do tend to exaggerate a little sometimes to cover their asses.

EDIT:

I re-tryed the traditional 2:1 KClO3/Al ratio but this time in a tube, since the burn rate of Chlorates increases a lot with pressure. Sure enough, 3g in a strong tube........BOOM, most impressive.

I tryed some sensitivity tests. Bashing the 2:1 as hard as I could on a concrete floor with a hammer produced nothing. As a control test i mixed a tiny amount of Sulfur with some Chlorate and tapped that. It went off with a loud bang, nasty. I then tryed some flash with sulfur mixed in - again a detonation but louder with a white flash. I cant believe they used to use these sulfur/chlorate mixes in fireworks.

Well I'm a happy man now, but I'm still not too keen on Chlorates. I just need a way to get rid of this crap Aluminium.

[iron raven]

hello,
I was wondering how does the recrystalizing process work? I thought if you mixed it you would end up with the crystals tangelled to gethre so how would separtate it?
any thing would be of help
iron raven

[arm]

Recrystalization for anyone who doesnt know what it is:

1. Take your impure compound and dissolve in the minimum quantity of boiling solvent.
2. Cool this solution down to room temp (maybe lower/higher).
3. The compound needed falls out of solution leaving the impurity's behind.
4. poor off solvent, wash and dry.
5. Repeat for greater purity if needed.

This only works (and or) works best however if:

1. The compound wanted is slightly soluble at lower temps but very soluble at higher temps.
2. The impurity's are more soluble than the wanted compound at room temp.

[Sonny Jim]

Bear in mind when reading this that I'm tired, so apologies in advance if this makes no sense, has already been covered, etc.

Thing that strikes me is, the NaClO3 weedkiller I have available, no matter the brand, is only 53% chlorate or thereabouts. The rest is fire retardant. Crap basically. Check your weedkiller and look for a 'with fire suppressants' label.

If this is the case, and you have not removed the fire retardant, this could be the problem.

You could soup up your potassium chlorate with sulphuric acid to make potassium perchlorate too. If memory serves, megalomania has a page on chlorates etc in his explosives section.

[Arkangel]

I may be being dappy here, maybe it's just that I'm a bit caned, however, I think that if you read a few of the posts in this thread, you'll see that these chaps are a little beyond the step of removing the fire suppressant, since they were talking about converting it to Potassium Chlorate.

Valid though your post is, if a little pointless.

There's plenty around on this and loads of UK sites about removing the suppressant

[Sonny Jim]

My apologies again. I was not intending to patronise people, far from it. But I am intending to get some sleep...

[zaibatsu]

Add H₂SO₄ to KClO₃?? I don't think that's the best idea I've ever heard.

[arm]

Just adding Sulfuric Acid to Chlorate would probably do very little in terms of conversion to Perchlorate. One possibility is the generation of Chloric acid (very bad) and Chlorine Dioxide (really not good for you). Attempting to use this very acidified Chlorate would be slightly suicidal.

You might be refering to something we were talking about in the 'Cooler' - chemical oxidation of Chlorate to Perchlorate. In this case you would be talking about the method that uses Lead Dioxide in concentrated Sulfuric Acid.

And Sonny Jim, the whole idea of adding a K2SO4 solution to a NaClO3 solution is to precipitate high purity KClO3.

[Sonny Jim]

What, therefore, do you make of this?

http://roguesci.org/megalomania/explo/perchlorates.html

Just scroll down until you get to potassium perchlorate.

On the note of potassium sulphate...

I know it is used as fertiliser, thanks to google, but thats just about as far as I have been able narrow it down to. Could any of you people tell me a little about this and where it can be obtained, brand names, etc. Thanks.

[arm]

Hmmm,

Personally I dont like the idea of adding Conc. H2SO4 to Chlorate. One of the tests you can do to determine if a substance is Chlorate is to add Sulfuric Acid to the substance. If you have Chlorate it tends to pop, splutter and maybe ignite. :(

Potassium Sulfate is usually sold under the old name of 'Sulfate of Potash'. I wouldnt bother using it - obtaining high purity KClO3 is more difficult because the difference in solubilities between the reaction products is small. I'm going back to the trusty old KCl method.

[Sonny Jim]

Well, I think I may try to prepare some anyway, but with the use of an ice bath, and being sure to keep the quantities small. It's worth testing I think. I shall run some tests and post up what happens, as I'm getting some more H2SO4 tomorrow.

Thanks for the advice regarding potassium sulphate.

[kingspaz]

for fucks sake. DO NOT ADD KClO3 TO H2SO4!!!!!

it spontaneously ignites/explodes. the release of ClO2 and other nasty oxidising gasses which will burn your lungs out.

[iron raven]

hello,
i was reading the file from NBK2000 and he said something bout making NaClO3 from of Nacl and H20 it was the reactin from NaCL + 3 H20 --> NaCLO3 + 3 H2

is this possible if so how? He said that electrolisis is needed but i have used Nacl and water in an experiment which used elcetrloisis and never had NaCLO3 form.
Any tghing would be of help thank u all.
iron raven

[Sonny Jim]

Yeah, I've heard of that method. I've employed it in a way but not to make sodium chlorate, but as part of the iron oxide preparation process for thermite.

I thought the reaction formed sodium hydroxide solution personally. I don't know very much about chlorate manufacture, but this site seems pretty detailed.

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/sodium.html

[vulture]

If carried out using a semipermeable membrane, NaCl electrolysis will yield NaOH.

However, when you are not using a membrane, a important sidereaction takes place.
The chlorine gas reacts with the solution to form HOCl, which then reacts further with the NaOH (as the compartiments are not separated) to form NaOCl. Because the electrolysis produces heat, the following reaction will also take place:

3NaOCl ---> NaClO3 + 2NaCl
3HOCl ---> HOCl3 + 2HCl

HCl and NaCl go back into the cycle untill they are finally totally consumed in the process, after which chlorate to perchlorate conversion (electrochemically) starts.

Note that this is just a simplified description of the process.

[Sonny Jim]

Oh, well when I was making my iron oxide I never used any membrane, I just stuck the electrodes in a jug with NaCl solution and switched on the power. Do you think I could have been making NaClO3 without knowing it? When I used to make iron oxide, I left the cell running for days at a time. Heat certainly was produced, and the water level decreased over time too.

I might set up my old equipment again and see if I can turn this idea into a reality.

[vulture]

It really depends on what you were using as an electrode.

[iron raven]

hello,
Could you's reckomened an electrdoe? becouse i really want sodium chlorate.
Anything would be of great help thanks.
iron raven

[IPN]

If you want the best electrodes available then use platinum as anode material and titanium as cathode material.
But you get ok results if you use graphite for both.

Check this page for more details:
http://huizen.dds.nl/~wfvisser/EN/kclox_EN.html

[vulture]

You mixed something up there. Usually platinum coated titanium is used as this is very durable material and not that expensive either, because the platinum layer is very thin. The other electrode can be graphite, iron,...

Graphite for both is still the most practical and delivers a more pure product than when using iron or other metals. Besides, a bit of graphite contamination in chlorate won't harm.

[iron raven]

Hello,
ok, this wat i em planning to do. Getting two grahite rods out of pencils placing them into a solution of NaCl and water the graphite rods will be hooked up to alligatro clips and a d/c convertar. wat should the ratio be of NaCl to water so that in the final sloution i will only have NaClO3 and no NaCl? Will the NaClO3 recyryistalize at the bottom of the container? If it does will the crystals be pure or near pure NaClO3 oir will it be heavily contaminted with NaCl?
any info would be of great help thak you all
iron raven

[blindreeper]

Iron Raven, did you not even read IPN's post http://huizen.dds.nl/~wfvisser/EN/chlorate_EN.html
Bloody hell now I am sick of noobies. Read the previous post beofre you post cause your obviously so excited about making NaClO3 that you can't even read a post!

[yt2095]

Iron Raven,

to address your question 1 at a time, 1`stly pencil lead will be piss poor to use, electrical resistance and clay inpurities coupled with the fact that you`ll only get milligrams of chlorate before your rods disintegrate.
go to a welding hire shop or a hardware store and buy something called gauging rods, they are great for chlotate making, just peel the copper foil off the outside of them 1`st, leave a little at the top to attatch your wire to and dip your connection in wax (stops the corrosion a little).
At a push, you can use the carbon rods from the inside of Zinc Carbon batteries, the big 6 volt square batteries they use in the road sign flashers when they do work digging roads up and leave for the night, do a drive-by and grab a few. open them up and you`ll find 4 cells in there, rip them open and take out the rods, wash them thouroughly.

next your sollution should be saturated at standard RTP,

next, if you leave the process going long enough (a few days) you`ll have converted the majority of the NaCl to to NaClO3 and be in the proscess of generating NaClO4 (even better)

re: the soluabilty issues, don`t worry about it, at this stage when filtered (carbon removal) the remaining NaCl will be almost insignificant. if it`s an issue though, convert it to KClO3 or even better KClO4. you`ll only have to re-filter that as KClOx salts are rather insoluable compared to common house salt.
don`t waste your filtrate though, use it in your next batch ( i hate waste)

do a search on here also, there`s a waelth of info re: this proccess and others.

all the best :)

[IPN]

Vulture:
The platinum wire is IMO perfectly fine for use in electrolysis.
Though the platinum coated titanium might be better..

As cathode I’m using copper witch is cathodically protected from erosion by addition of chromates to the electrolyte.
(You can read more about that from Visser's page)

Oh, and iron raven I recommend that you read about chlorate manufacture from Wouter Visser's page before you try making any.