making potassium (per) chlorate

[WSM]

It's not that I can't find methylene blue, they are cheap and readily available at any science/chemical shops... the issue is I just did not happen to have them on hand so I tested it with a really unscientific method... Of course best way to be sure is methylene blue... I just have no idea if there's a good test for residual chlorate.

 

I'm pretty sure the black bit is from the anode, I just can't be sure where... The anode itself looks like nothing has happened but then I have all these black bits. The smell of ozone is also very pervasive when the cell is opened for inspection. Only way I know it's ozone (and not chlorine) is because it smells like one of those air purifier (that makes ozone by the way). In fact people buy ozone generator all tuhhhe time thinking it will improve indoor air quality but the fact is, surface level of ozone isn't good for you.

 

I need to find another power supply so I can also run a potassium chlorate cell concurrently.

There are three spot tests for chlorate that I've used. The most sensitive uses indigo carmine and sodium sulfite if memory serves. All three spot test reagents work but none of them are stable and will not last much past a month at most when made up.

 

About the "black bits" you see, are they LD or do they come from somewhere else? What sort of material is your cell made of? Some materials will break down in the cell environment, leaving black flakes as residue. Please share as many details about your setup as you can so we can determine what's happening.

 

Thanks

 

WSM

Edited May 9, 2014 by WSM

[taiwanluthiers]

The cell is a polyproplyne container, with a CP titanium (3mm thick) cathode and LD anode. A vent hole with an air compressor hose was used to vent the gas outside, and I'm using a computer power supply to run 5v through the cell... I tried getting 7v but it won't work, and 12v is way too high. I spoke with the guy I bought it from and he said to not worry about it since it should go away in subsequent runs, but if it started flaking off in major ways to let him know.

[taiwanluthiers]

Update: After a few days of run, producing maybe 70 grams of perc, the LD anode seems to have a layer flaking off, near the center of the lower portion. It exposed a black but smooth surface, and it looks like MMO rather than LD. I'm thinking the anode is toast and given the expense of trying to produce a workable LD anode, platinum seems to be the way to go. It's really hard to see in the picture but there's a whole chunk missing at the middle in the lower portion, and a much larger area of what looks like space between the MMO and the LD.

 

I think I'm just going to try that 1 micron 2x3" Platinum plated anode.

Edited May 9, 2014 by taiwanluthiers

[WSM]

Update: After a few days of run, producing maybe 70 grams of perc, the LD anode seems to have a layer flaking off, near the center of the lower portion. It exposed a black but smooth surface, and it looks like MMO rather than LD. I'm thinking the anode is toast and given the expense of trying to produce a workable LD anode, platinum seems to be the way to go. It's really hard to see in the picture but there's a whole chunk missing at the middle in the lower portion, and a much larger area of what looks like space between the MMO and the LD.

 

I think I'm just going to try that 1 micron 2x3" Platinum plated anode.

That's disappointing. Did you monitor the voltage, amperage and temperature? I wonder if the (uncontrolled) computer power supply overloaded the LD anode, causing the problem or whether a regulated supply would be better?! I'll try to get my LD anode ready to run, this weekend.

 

A fellow enthusiast recommended that I use my variable power supply and run it with constant current and see if I don't have better results. I may have to do just that and see exactly what's happening with these anodes.

 

WSM

[WSM]

I just received the LD anode. From the packaging it was clearly from China... not sure what its use are in industry but the coating appears intact, no sign of shipping or other damages. The anode itself feels heavy (because it's lead). Will see how it works. There are some flaking on the top piece that is connected to the mesh, but I have a feeling it's meant to be that way, since that top section wasn't really MMO (just bare Ti) so it would seem logical that the LD doesn't adhere well to that.

 

I'll let you know once a tank is set up... I think I would like to try a run with potassium chlorate and see how that works...

I wonder if sodium chlorate isn't easier on an LD anode or if that even matters? I'm planning to use NaClO3 rather than KClO3 for my first run using the patsroom LD anode (100mm x 100mm). We'll see...

 

WSM

[WSM]

Okay, I took the plunge and ordered some of the low cost LD anodes to try. We'll see if and how they work out. I plan to monitor various aspects of the setup and running conditions in an attempt to track what works and what harms these electrodes.

 

I hope we can find a happy solution to the observed problems. Even if we need to run them with a gentle current, if they hold up and run slowly, that's okay (slow perchlorate for a long time is preferable to a destroyed anode) and it'll work for me.

 

I'll report here what I observe and my results.

 

WSM

Edited May 9, 2014 by WSM

[taiwanluthiers]

I'm running at 5 volt at about 7 amp. Temperature is about 50C, and it had to be that otherwise the chlorate would precipitate out and the level would be too low. I just couldn't think of how to purify sodium chlorate. Honestly it doesn't seem to be running that hard, considering the size of the anode can handle at least 3x what I am putting through.

[WSM]

I'm running at 5 volt at about 7 amp. Temperature is about 50C, and it had to be that otherwise the chlorate would precipitate out and the level would be too low. I just couldn't think of how to purify sodium chlorate. Honestly it doesn't seem to be running that hard, considering the size of the anode can handle at least 3x what I am putting through.

Thanks, taiwanluthier; that's helpful. Let's see if a sodium chlorate cell runs any better. I know it can run cooler and keep everything in solution. Maybe it'll run better? I'm not sure so this will be a learning experience.

 

WSM

[taiwanluthiers]

I'm not even sure what's the erosion rate of platinum, or how long will a 1 micron pt coating will last. I have seen Swede say how he can make perc easily with platinum though...

[Mumbles]

You purify sodium chlorate the same way you do potassium chlorate. Sodium chloride is going to be the main contaminant. I would dissolve the crude product in boiling water, which will destroy any lower chlorine oxides, filter if there is any insoluble residue, then cool it down to crystallize. Sodium chloride's solubility basically doesn't change with temperature, whereas the chlorate changes dramatically. Anything that precipitates will be fairly clean chlorate. Clean enough to move on at least I'd suspect.

 

I seem to remember there being some crud on the surface of some older MMO or LD anodes available on ebay. The seller was redlaser or laserred or something like that I think. I'm sure it's documented somewhere here, but I believe giving the anode an initial soak in dilute HCl tended to clean it up. This might be something to do to avoid the initial batch being contaminated with that stuff. Also, the air compressor hose (if black) might be being attacked by the corrosive cell vapors and leaching back into the cell causing the issue observed.

[taiwanluthiers]

The compressor hose is polyurethane, not rubber.

[Mumbles]

I don't see your point. A real point would be that the tube is blue or red or clear. You're seeming to intend to say that only rubber is susceptible to the cell vapors. Poly urethane is attacked by HCl and almost certainly by chlorine gas. Depending on which actual polyurethane you use, it's also somewhere between "Eh" and crap with sodium hydroxide and sodium hypochlorite.

 

So, again, if your hose is black, this might also be an issue. Trying with something else could be better, or at least rule this out.

[taiwanluthiers]

I know it's not the hose because it's bright orange translucent. I have run chlorate on it with MMO and it did not discolor the solution in any way.

[pyrojig]

Heck I have run pvc hose as a vent and it worked fine ( just a suggestion ) and a cheap source . I too dont believe that there are contaminates resulting from the hose he describes .

[taiwanluthiers]

I just wrote to the guy I bought the anode from, he said he'll send me another one, but I asked for platinum plated titanium instead of LD and he said ok, but will have to wait a couple of weeks before he gets it in. I hope I have better luck with platinum...

[taiwanluthiers]

You know I read in this thread how in perchlorate synthesis, the run ends if the current goes up. However it said that the current can rise suddenly and if you let it run much after that, it will destroy the anode. The post mentioned rigging some kind of a switch or something. The question is, will a circuit breaker for electrical wiring work? I mean they are designed to shut off after the rated current is exceeded so say if your cell normally consumes 15 amps, and the current goes up to 30 amps when the run is complete how about just putting a 20 amp circuit breaker in the circuit so when the current consumption goes up, the breaker will trip?

[WSM]

You know I read in this thread how in perchlorate synthesis, the run ends if the current goes up. However it said that the current can rise suddenly and if you let it run much after that, it will destroy the anode. The post mentioned rigging some kind of a switch or something. The question is, will a circuit breaker for electrical wiring work? I mean they are designed to shut off after the rated current is exceeded so say if your cell normally consumes 15 amps, and the current goes up to 30 amps when the run is complete how about just putting a 20 amp circuit breaker in the circuit so when the current consumption goes up, the breaker will trip?

 

I like that idea. If the statement about the current rising at the end-of-run in pechlorate cells is true, this is a neat fix to the anode damage problem (as long as the damage is happening at the end of the run and not constantly while it runs).

 

If all this is true, I suppose a controller with tight specifications can be built to safely shut down the perchlorate system when this point is reached, and preserve the whole system and product.

 

I think this bears further study and consideration...

 

WSM

[taiwanluthiers]

I guess another solution is to make sure that point is never reached, by charging the cell with fresh chlorate daily... obviously this will only work for potassium chlorate to perchlorate runs, as the product can just be harvested once it accumulates and the cell could be running continuously.

[WSM]

I guess another solution is to make sure that point is never reached, by charging the cell with fresh chlorate daily... obviously this will only work for potassium chlorate to perchlorate runs, as the product can just be harvested once it accumulates and the cell could be running continuously.

 

It should also work in a sodium system. The trick is harvesting the perchlorate, removing the chlorate and then converting the sodium salt to the corresponding potassium salt. It must be easier than we think, because that's the way industry does it; they need an efficient system to be profitable.

 

WSM

[Arthur]

Does anyone have access to anyone who used to work for Pepcon? Someone must know how their process was controlled. I suspect that in industry sodium salts are made and the liquor after perc extraction is simply recycled to the chloride inlet. I don't think it would matter if some perc went back into the chlorate cell.

[frank]

Can somebody help my with a calculator?

I have a cell with 9 kg naclo3. 9 liter cell. 11 amp. 40 degrees Celsius. How long dus it taken to convert to naclo4.

 

Thanks allot

 

I make that about 9 to 10 hours per 100 grams NaClO3.

 

From here:

http://oxidizing.typhoonguitars.com/chlorate/runper.html

 

(it would be great if it were six minutes!)

 

Thanks for putting up the that page taiwanluthiers.

 

Frank

[pyrojig]

 

I think this bears further study and consideration...

 

WSM

I couldnt agree more!!

WOW This topic has come back to life!!!! Loving it. All you guys are inspiring , I feel that we're on the break of a new era in technology. Keep at it , and lets make history!!

Love seeing great minds at work....together.

Edited May 15, 2014 by pyrojig

[Arthur]

If I had a cell running sodium chloride to chlorate, at a reasonable completion level (chloride low but not low enough to cause damage) could I simply cool the solution to precipitate enough chloride to send the chlorate liquor straight on to a cell with platinum electrodes?

[Mumbles]

The solubility of sodium chloride changes very little with temperature, so that wouldn't be a viable way to remove chloride. This property is ideal sometimes, but a pain in the butt at others.

[bikemaster]

Go take a look at this at page 25 : http://books.google.fr/books?id=rtm_bjQd8SUC&pg=PA32&lpg=PA32&dq=Chem.+Met.Eng.+44,+692+%281938%29&source=bl&ots=mMw-bpR9F3&sig=h7vpf-y4eUyPhC5CPNKnNSRFtbk&hl=fr&sa=X&ei=FJl0U-P0EuT00gWK7YCABw&ved=0CDsQ6AEwAQ#v=snippet&q=sodium%20chlorate&f=false

 

It explains very well the separation technique that is use in sodium chlorate plant. Keep in mind that these process are made to run continuously, so for them, keeping this type of concentration are easy. But for us, running batch, we need to add chloride many time before we get any chlorate to crystalize.

Edited May 15, 2014 by bikemaster