Making perchlorate

[WSM]

If you ran KCl to KClO3 using Pt, you probably also generated some quantity of perchlorate as well.

Pt won't be ruined quickly by excess chloride, but it will definitely erode faster than if chloride is minimized. I think in the end, with Pt at least, the goal is to get enough perchlorate out of it so that the cost per kilo remains below (hopefully WELL below) commercial perc.

That's a good article, and emphasizes again that industrially, they make this stuff very quickly with high power. I keep thinking I'd like to try this - a very small cell with HUGE electrodes and high current, and a stock chloride trickling in at some low flow, let's say 500ml per hour. The cell is going to get to near boiling. If using KCl what comes out is going to be very high in chlorate, and as it trickles into a cooling tank, the KClO3 is going to crystallize out quickly. From there, the depleted liquor flows into a replenishment tank, which has a thick bed of KCl at the bottom.

There are a bunch of interesting ways to do this, that's for sure.

 

Hi Swede,

 

Better read that article again. If I read it right, with platinum electrodes, higher efficiency is best reached between 35^oC and 45^oC (which is why they use cooling coils commercially). It's an interesting article, but I'd like to know the source.

 

WSM

[pdfbq]

Reason why i attached it

http://www.oocities.org/capecanaveral/campus/5361/chlorate/encyperc.html

[Swede]

Hi Swede,

 

Better read that article again. If I read it right, with platinum electrodes, higher efficiency is best reached between 35^oC and 45^oC (which is why they use cooling coils commercially). It's an interesting article, but I'd like to know the source.

 

WSM

 

Sorry, wrong thread. I was thinking chlorate and MMO. Just another variation on the "one pass into a collection chamber" thing. I really need to do some math and figure out what sort of electrolyte flow with 16% chloride at "X" amps would take that electrolyte down to 5 or 6 percent chloride.

[pdfbq]

http://www.youtube.com/watch?v=fro-L5gSyh4&feature=share&list=UUIgKGGJkt1MrNmhq3vRibYA

Not 'that' interesting but what is interesting is that the color of the Pt at the end, after the molten NaOH treatment. It is just the color my Pt anode gets when I run it too long and the current has gone up. It makes sense that your Pt gets oxidized at the end I think and I also think it's something you do not want.

Edited September 18, 2012 by pdfbq

[WSM]

Sorry, wrong thread. I was thinking chlorate and MMO. Just another variation on the "one pass into a collection chamber" thing. I really need to do some math and figure out what sort of electrolyte flow with 16% chloride at "X" amps would take that electrolyte down to 5 or 6 percent chloride.

 

That does sound useful. Please post or blog it if you do. That sort of information would be a great reference tool.

 

WSM

Edited September 19, 2012 by WSM

[taiwanluthiers]

I think you're supposed to chemically destroy any remaining chlorate...

 

So with the right setup you can really make perchlorates at lower cost per kilo than commercial perchlorate? Pt electrode is really expensive.

[Swede]

Well, that's the goal. I forget the exact $$ amount, but our chlorate ended up costing I think about 65 cents per pound, vs. $12/lb at Skylighter. If we can extend the process to perchlorate, I think it can be done for a couple $$ per pound.

 

I think it's obvious, though, that we're doing this for fun. Cost for the oxidizers is not the motivation.

[taiwanluthiers]

Just looking at the numbers, the cheapest thing would be sodium chloride. Reagent grade potassium chloride (needed for the conversion of sodium perchlorate into potassium perchlorate) is 3 dollars a pound for me, and I think there is fertilizer grade potassium chloride that is even cheaper, however I do not know what kind of impurities it has (it appears reddish pink). I wonder if I can get perchlorate by putting potassium chloride in a cell, because the solubility of potassium chlorate is kinda low.

 

So to get good, pure grade of potassium chloride it is 3 dollars a pound and that's not counting the electrodes (probably cost a crapload), the power supply (if computer PSU does not work, then a dedicated high current power supply is needed, also really expensive). In the end not really giving me a cost advantage...

 

I really would love to be able to make potassium perchlorate at a couple of dollars per Kg, because I currently pay 40 dollars per Kg for lab grade perchlorate.

[WSM]

Just looking at the numbers, the cheapest thing would be sodium chloride. Reagent grade potassium chloride (needed for the conversion of sodium perchlorate into potassium perchlorate) is 3 dollars a pound for me, and I think there is fertilizer grade potassium chloride that is even cheaper, however I do not know what kind of impurities it has (it appears reddish pink). I wonder if I can get perchlorate by putting potassium chloride in a cell, because the solubility of potassium chlorate is kinda low.

 

I really would love to be able to make potassium perchlorate at a couple of dollars per Kg

 

If you can get agricultural KCl at a good price, try recrystallizing it to remove unwanted material before using it in a cell. It may take a few times but you should end up with very pure KCl if you watch the details.

 

Good luck.

 

WSM

Edited September 19, 2012 by WSM

[taiwanluthiers]

what kind of impurities do agricultural grade KCl have? It appears red from the picture, and it showed the bag it came from that says contains 60% soluble KCl.

[WSM]

what kind of impurities do agricultural grade KCl have? It appears red from the picture, and it showed the bag it came from that says contains 60% soluble KCl.

 

Who knows (I can't even guess)?!

 

WSM

[Mumbles]

Look more carefully. It probably says 60% soluble potassium as potassium chloride, or 60% potassium as K2O. They measure fertilizers with an NPK rating set of numbers. Potassium is measured as equivalent K2O. 60% is relatively pure. 62% is the highest I've ever seen. Recrystallize it properly, and you'll be fine.

[taiwanluthiers]

Here is the stuff as shown by the product page:

 

 

 

 

The Chinese says "Potassium Chloride, Water soluble potassium Chloride 60%, place of manufacture: Canada" and it lists an address in Quebec but it appears to be of an exporter. The powder appears red which is hard to believe it's 98% pure... dunno what the red stuff is. As for the price its 2.50 dollars for 3Kg

Edited September 20, 2012 by taiwanluthiers

[pdfbq]

I use this type of KCl (not exact this one, but Solumop brand, same price).

When you are making perc and you do it the NaCl way it makes not much sense to recrystallize this KCl first.

I just use it as is for the double displacement reaction (although I dissolve it in hot water and let the impurities sink to the bottom overnight).

After the double displacement to KClO4 I recrystallize twice but this is something one has to do anyway.

Edited September 20, 2012 by pdfbq

[taiwanluthiers]

So if I am precipitating from NaClO4 then how do I get all traces of the sodium out? I heard its impossible to remove all impurities of sodium and even a little bit will destroy the color.

 

This could be a way for me to get Ammonium perchlorate cheaply...

[WSM]

So if I am precipitating from NaClO4 then how do I get all traces of the sodium out? I heard its impossible to remove all impurities of sodium and even a little bit will destroy the color.

This could be a way for me to get Ammonium perchlorate cheaply...

 

The commercial way is to use slightly less than the stoichiometric amount of KCl and rinse the crystals of potassium perchlorate with cool/cold water, then return the rinse water to the NaCl replenishment tank before going to the chlorate cell (in a Continuous system). The continuous perchlorate system yields ~99.5% KClO4 and the sodium is low enough to present no problems with colors.

 

For our purposes, recrystallizing multiple times can yield a very pure product, notwithstanding some losses. Watch the solubilities and temperatures and you can minimize those losses.

 

Crystallizing is natures method of purification; the different molcules naturally segregate themselves in the process. Where the correct crystallization environment exists, the resulting crystals are very pure. Our job in the process is to create that environment.

 

Whether cheap or not, this same process is how industry makes NH₄ClO₄. The difference is in using ammonium chloride instead of potassium chloride and the differing solubilities.

 

WSM

Edited September 20, 2012 by WSM

[WSM]

I would chemically destroy all chlorates though before doing the reaction... even a small trace of chlorate can make the perchlorate very sensitive. Also if you're making ammonium perchlorate any trace of chlorate can be dangerous.

As for the brine solution being fed back... the concern is contamination from the further handling... plus NaCl is cheap... much cheaper than KCl that's for sure. Not much savings to be had unless its done on an industrial scale.

 

For our purposes, I agree with the notion of destroying the chlorate before converting the sodium perchlorate to the potassium salt, IF we can do so economically. This calls for a separate system for each stage, i.e., a chlorate cell (NaCl -> NaClO₃), then a perchlorate cell (NaClO₃ -> NaClO₄).

 

I think if we already have the sodium chloride in solution, why throw it out and make a new sodium chloride solution? Why not recharge it with more sodium chloride and run it again? The starting material may be cheap but consider the extra effort you're adding, plus there is more to a good chlorate cell liquor than just salt in water...

 

WSM

[taiwanluthiers]

Well, you have to make sure all chlorates are gone because chlorates (even a small trace) still make the resulting perchlorate as unstable as chlorate, meaning same rules about not having sulfur, etc. (correct me if I am wrong), and for ammonium perchlorate you do not even want a trace amount of chlorates.

 

What about crystalize the product out once, then chemically destroy any remaining chlorates? I do not know if ammonium chlorate is safe enough in a solution to allow for this. I believe the literature I've read said to crystalize out the sodium perchlorate first, then chemically destroy any remaining chlorates, and then react with ammonium chloride. This could account for the high cost of ammonium perchlorate...

[pdfbq]

What I did was running my perc cell till the current went up, also my anode turned brown. Then I destroyed all chlorate by adding to the cooled down solution sodium meta bisulphite and then heat slowly to boil.

Now that is really easy. Removing all chloride from perc is also easy but a bit labour intensive. After the double displacement filter and wash with cold water rekrystallize twice. I tested with silver nitrate and all Cl^- ions are gone.

[Mumbles]

Until you can manage to actually make a functional and efficient perchlorate cell Taiwanluthiers, I wouldn't worry about the details if I were you. They are seriously minor issues compared to the big picture of needing to actually make a perchlorate cell. If you can accomplish that, purifying the product will be trivial. My first inclination would be to chemically destroy the chlorate before crystallization. Chemical destruction of chlorate adds additional impurities that will need to be removed anyway. If you purify it, then remove all the chlorate, you'll need to subsequently recrystallize at least one or two more times.

[Swede]

 

So to get good, pure grade of potassium chloride it is 3 dollars a pound and that's not counting the electrodes (probably cost a crapload), the power supply (if computer PSU does not work, then a dedicated high current power supply is needed, also really expensive). In the end not really giving me a cost advantage...

 

I really would love to be able to make potassium perchlorate at a couple of dollars per Kg, because I currently pay 40 dollars per Kg for lab grade perchlorate.

 

Look for KCl as water-softener substitute. A 40 pound bag costs less than 50 cents a pound, and it is more than adequate for this process.

 

Reagent-grade stuff is cost=prohibitive, and agricultural KCl is going to have more impurities than the water-softener grade.

[Arthur]

Does Dann2's web site still exist? The old geocities site was informative

[patsroom]

@ Arthur "Does Dann2's web site still exist? The old geocities site was informative"

 

http://wayback.archi...nl/indexEN.html

The wayback archives are the only place I know to retreive his information from. In fact there are a few old sites that are no longer anywhere but in the wayback archives. Sometimes they have it store in whole sometime just a few pages is all you can find there in the archives. Like dexter's lab, not all the pictures are saved, but I remember of the site when it was up it had some good sample pictures.............Pat

Hopes this helps..........

Edited September 20, 2012 by patsroom

[pdfbq]

Just ad these two here because they might disappear.

http://www.oocities....e/napermut.html

 

 

Did not study them yet,

[frank]

Dann2's web site is here

 

www.oxidixing.110mb.com

 

It's inclined to be down quite a lot.

 

While making perchloric acid may seem a very dangerous, cumbersome way to make other perchlorates it is quite easy to make

from sodium perchlorate (a water solution) and conc. HCl (easy to obtain). It's OK if the Na perk. has some chlorate in it, a few % say, as the chlorate will be all destroyed in the processs.

Strong acids are suggested as a way of destroying all residual chlorate in perk. anyways!

 

The process consists of adding a concentrated solution to the acid (or other way around). You immediately get a ppt. of NaCl and the solution will turn yellow if there is chlorate present (ClO2 gas). Do this outside and keep upwind or use fume cupboard.

 

Filter off NaCl and boil long enough until very white fumes appear (whiter that what has been coming off up until then) you will have around 70% perchloric acid @ around 200 degrees. Let cool and a small amount of sodium perk, may come out. The

acid will have very little sodium in it.

Then neurtalize with whatever carbonate or hydroxide you want.

 

Keep the acid away from organic substances are there will be trouble. The 70% stuff can be stores.

 

Frank