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making potassium (per) chlorate


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#5341 WSM

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Posted 30 May 2021 - 07:28 PM

guys, i purchased some potassium chlorate as part of a kit about 5 years ago, it came in a plastic bag in a brown box and was originally powder. i just opened it for the first time and it is hard as rock. any advice on how to break it up. even into smaller pieces that could then be ground into powder? best ways? is it now unusable?


If your oxidizer is caked hard, you can powder it through a sieve.

Place the sieve, screen side up, on a large sheet of paper*; then grate the clump of hardened oxidizer through the metal screen.

Take your time and it should all return to powder as you work it through the screen.

WSM B)

 

Edit: *Actually I use two sheets of paper for material handling and spill prevention. Also, my preference is to use stainless steel screen, which lasts longer and costs nearly the same as brass screen when purchased in bulk.


Edited by WSM, 03 June 2021 - 07:41 AM.


#5342 sefrez

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Posted 07 June 2021 - 10:23 PM

Quite coincidentally to this post I have been wondering recently if what I have been experiencing with my made KClO3 is similar to that of others. As champ739 mentions, I too find the chlorate to cake together strongly. It's a bit of a pain to get it through a screen. I actually find it easier to break up in a mortar. My KClO4 is pleasant to work with, not much caking at all.

 

As for the KClO3, the extent to which it is caking could strongly be in relation to me storing it a bit packed in a container. I'm not using a desiccant either (nor for the KClO4.) Should I be?

 

Particle fineness plays a big part in in how it cakes too, and I can qualitatively say on its fineness that it has been milled to the point where when rubbed between fingers it falls between fingerprints and individual particles can't be felt.

 

I wondered if impurity was an issue, so, assuming the main impurity to be KCl, I did a silver nitrate / chromate chloride titration. I determined on KCl impurity alone, it is at least 99.8 pure. So I'm thinking KCl isn't the issue. I use KCl water softener which is already supposedly 99.1% pure.

 

My KClO3 might be suffering these affects from being too pure.  :P Thoughts?



#5343 Arthur

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Posted 10 June 2021 - 10:45 AM

Many chemicals will have an anticake additive on top of the main ingredient. Likely but not certain that this will be fumed silica.



#5344 WSM

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Posted 20 July 2021 - 10:43 AM

Many chemicals will have an anticake additive on top of the main ingredient. Likely but not certain that this will be fumed silica.




I'm not sure about other oxidizers but commercial ammonium perchlorate is usually roller milled with a small amount of tricalcium phosphate (TCP) for an anticake agent. Roller milled AP has spheroidal particles that are safer to handle in bulk (think: huge military solid rockets).

WSM B)

Edited by WSM, 20 July 2021 - 10:44 AM.


#5345 WSM

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Posted 17 September 2021 - 06:10 AM

As the year wears on, I'm working on clearing and organizing my work spaces so I can eventually get back to my efforts in electrochemical research. 

 

My last active work was on the sodium chlorate system, for feed stock in perchlorate making research. The original cell made about 10 Lbs. of reasonably pure NaClO3, but took about 6 weeks and fair efficiency (no pH adjustments in that run). My focus after that was to purify my KCl before reacting any of it with NaClO4, to minimize any contaminants being introduced into the final product.

 

I have also decided to build a prototype high temperature sodium chlorate cell (which I've done to a point) which promises to produce much more product in less time and with much more efficiency. I have yet to populate the lid of the new cell with threaded holes for the various fittings needed, but will do so as time allows. I plan to set it up and do some initial runs hopefully as soon as next Spring. I'll post my progress as this develops.

 

My goal is to produce enough sodium chlorate that I can run all of my perchlorate experiments from one larger batch, eliminating as many variables as possible. My first small experiments used two separate batches of commercially sourced NaClO3 and I fear they weren't similar enough to trust the results I observed. I have no access to commercial sodium chlorate, so I've been studying producing my own, and due to careful purification of the salt used to make brine for the electrolyte, I managed to make very pure sodium chlorate. I hope to do the same with potassium chloride solution so I can get my home made potassium perchlorate at least as pure as commercial grade, or better!

 

I'll post more as things progress.

 

WSM B)


Edited by WSM, 20 September 2021 - 08:00 AM.


#5346 AndyPyroNoob

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Posted 17 September 2021 - 06:55 AM

I have the basics down on how to get a Perchlorate cell happening. I thought I could actually buy KCLO4 here in Australia but I think the person selling it has stopped/Not responding. So my only other option is to make it. I have made KCLO3 no issues. Using MMO Electrodes(from electrode supply)

 

Now I want to try some KCLO4.

 

I can buy the Lead coated Anode here in Aus on ebay which will do the job, But I have also found a much cheaper Lead anode which appears to be pure lead at 1mm thick. https://electrodesup...6-by-1mm-thick/

I could buy like 15 of them cheaper than I could buy one of the lead coated anodes.

 

Would that electrode be suitable for a Perchlorate cell or am I better off getting a Lead coated MMO/TI anode? Like this one (https://www.ebay.com...&frcectupt=true)

I would prefer to spend more money to get it right first time than try to skimp and for my cell not to work well.

 

Also in regards to the PSU. I find a lot of information from you can run a perchlorate cell at 5v with a few amps(2A-3A) to running it at 12v with 30 amps. My current PSU is a cheap lab bench 0-30v 10amp adjustable lab bench PSU. Speed is not a concern for me, I don't mind if it takes weeks to make even a small batch of KCLO4. I understand that as the Chloride runs out of the solution it then starts changing the chlorates to perchlorates.

 

Also which cathode is best with either lead anode? Can I use my MMO Cathode(which is titanium) in the Perchlorate cell? I also have a small sheet of titanium too I can use.

 

 



#5347 WSM

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Posted 17 September 2021 - 07:48 AM

Hi Andy,

After a quick look at the links you posted, I recommend the lead dioxide anodes, regardless of cost.

The lead electrode will do nothing useful. The lead dioxide, if properly made and used will definitely convert sodium chlorate into sodium perchlorate. Plain lead won't.

Regards,

WSM B)
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#5348 sefrez

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Posted 17 September 2021 - 10:20 PM

As the year wears on, I'm working on clearing and organizing my work spaces so I can eventually get back to my efforts in electrochemical research. 

 

My last active work was on the sodium chlorate system, for feed stock in perchlorate making research. The original cell made about 10 Lbs. of reasonably pure NaClO3, but took about 6 weeks and fair efficiency (no pH adjustments in that run). My focus after that was to purify my KCl before reacting any of it with NaClO4, to minimize any contaminants being introduced into the final product.

 

I have also decided to build a prototype high temperature sodium chlorate cell (which I've done to a point) which promises to produce much more product in less time and greatly more efficiently. I have yet to populate the lid of the new cell with threaded holes for the various fittings needed, but will do so as time allows. I plan to set it up and do some initial runs hopefully as soon as next Spring. I'll post my progress as this develops.

 

My goal is to produce enough sodium chlorate that I can run all of my perchlorate experiments from one larger batch, eliminating as many variables as possible. My first small experiments used two separate batches of commercially sourced NaClO3 and I fear they weren't similar enough to trust the results I observed. I have no access to commercial sodium chlorate, so I've been studying producing my own, and due to careful purification of the salt used to make brine for the electrolyte, I managed to make very pure sodium chlorate. I hope to do the same with potassium chloride solution so I can get my home made potassium perchlorate at least as pure as commercial grade, or better!

 

I'll post more as things progress.

 

WSM B)

 

What are your sources for NaCl and KCl? Are you re-crystalizing as a step in your purification?

 

I have the basics down on how to get a Perchlorate cell happening. I thought I could actually buy KCLO4 here in Australia but I think the person selling it has stopped/Not responding. So my only other option is to make it. I have made KCLO3 no issues. Using MMO Electrodes(from electrode supply)

 

Now I want to try some KCLO4.

 

I can buy the Lead coated Anode here in Aus on ebay which will do the job, But I have also found a much cheaper Lead anode which appears to be pure lead at 1mm thick. https://electrodesup...6-by-1mm-thick/

I could buy like 15 of them cheaper than I could buy one of the lead coated anodes.

 

Would that electrode be suitable for a Perchlorate cell or am I better off getting a Lead coated MMO/TI anode? Like this one (https://www.ebay.com...&frcectupt=true)

I would prefer to spend more money to get it right first time than try to skimp and for my cell not to work well.

 

Also in regards to the PSU. I find a lot of information from you can run a perchlorate cell at 5v with a few amps(2A-3A) to running it at 12v with 30 amps. My current PSU is a cheap lab bench 0-30v 10amp adjustable lab bench PSU. Speed is not a concern for me, I don't mind if it takes weeks to make even a small batch of KCLO4. I understand that as the Chloride runs out of the solution it then starts changing the chlorates to perchlorates.

 

Also which cathode is best with either lead anode? Can I use my MMO Cathode(which is titanium) in the Perchlorate cell? I also have a small sheet of titanium too I can use.

 

 

 

I am unsure what you mean by "MMO Cathode(which is titanium)". If you mean a MMO on titanium substrate, you shouldn't. I believe the reducing at the cathode destroys it. You want pure titanium as far as I know.



#5349 AndyPyroNoob

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Posted 17 September 2021 - 10:25 PM

I am unsure what you mean by "MMO Cathode(which is titanium)". If you mean a MMO on titanium substrate, you shouldn't. I believe the reducing at the cathode destroys it. You want pure titanium as far as I know.

Sorry. I mean that my MMO electrodes. one is MMO, the other is Titanium. So the Titanium Electrode will be ok to use with the Lead Dioxide Electrode. :)


Edited by AndyPyroNoob, 17 September 2021 - 10:25 PM.


#5350 WSM

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Posted 20 September 2021 - 07:39 AM

 

What are your sources for NaCl and KCl? Are you re-crystalizing as a step in your purification?

 

 

I'm using water softener salt (for both sodium and potassium chloride brines). I've found recrystallization unnecessary with the process I use and I'm getting very good results.

 

I got the original idea from a website description of an industrial sodium chlorate plant operation. They start their operation with raw bulk salt, dissolve it with water to make the raw brine. Next they treat the brine with sodium carbonate and sodium hydroxide to react any calcium or magnesium (plus also any soluble iron according to Mumbles) to form insoluble precipitates with are filtered out.

 

I find this step leaves the brine somewhat alkaline, but I've treated the alkaline brine with dilute HCl which solves my concerns. In my process, I first dissolve the water softener salt, then filter out the course sand, pebbles and iron scale that I can see. Next, using a vacuum filtration system with slow grade laboratory filter paper, I filter out the remaining fine silt left in the brine. 

 

Now that the visible contaminants have been removed, I treat the clear brine with 1M Na2CO3 (sodium carbonate) solution, which leaves the brine looking like milk (opaque white). After letting the treated brine sit over night, the fine precipitates all settle to the bottom of the reaction vessel (a 5 gallon PE bucket in my case) and then I carefully decant the clear liquid off the precipitate. I next vacuum filtered the residue to remove the fine white precipitates of magnesium hydroxide and calcium carbonates (plus whatever else might have precipitated) through a slow grade filter paper and added the remaining clear filtrate to the other clear, now purified brine. 

 

These steps left the brine pure but alkaline so I treated the brine with dilute hydrochloric acid till the brine was either neutral or slightly acid and ready for use as the electrolyte in my sodium chlorate cell.

 

Potassium chloride brine is treated similarly, but with using 1M K2CO3 (potassium carbonate) solution, instead.

 

By purifying my brine before using it as the electrolyte in my electrochemical cells, I saw a yield of respectably pure product as a result. My sodium chlorate harvest looked like very clear jewels and no recrystallizing was required or needed.

 

My opinion is that taking the extra effort to purify our starting and process materials, we can produce end products that are as pure, or even better than commercial chlorates and perchlorates.

 

WSM B)

 

Edit: By using these, or similar, purification steps, I think a starting material even as impure as agricultural KCl could be brought up to lab grade quality and make excellent oxidizers.


Edited by WSM, 20 September 2021 - 07:49 AM.


#5351 sefrez

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Posted 20 September 2021 - 02:23 PM

I see. I used that same procedure when I started out using crap expensive food grade salt. It had calcium silicate in it as anti-cake which was a pain to filter off. I noticed treating it with NaOH caused additional calcium silicate to come out of solution (along with anything else) and it made the calcium silicate easier to filter because it consolidated into fluffy web like structures. I used HCl to neutralize after.

 

Now, like you, I use water softener. Since using this source for Na/KCl, I have stopped that purification step and now just dissolve the large crystals/pellets in the cell solution directly and filter off the obvious impurities - which isn't that much. I can't remember for sure, but I think I did both acidification and basification to a solution of the KCl salt and no precipitates were found. I know I didn't do it with the NaCl. Though, instead of pellets, they are large crystals which appear quite pure. It is nice to have brine solutions ready to go as opposed to needing to dissolve the salt in the cell each time it needs to be replenished, but I was having to boil down the solution a lot with adding brine which was really annoying. I guess if you have a high temperature cell, that isn't as much of a problem because of higher water vapor leaving in the process.

 

What brand of softener do you use? I am using Diamond Crystal.

 

I do still get white precipitate on the cathodes that needs to be brushed off after a while, but I got that even with the purification step when using the food grade salt.


Edited by sefrez, 20 September 2021 - 02:25 PM.


#5352 WSM

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Posted 21 September 2021 - 11:16 PM

"What brand of softener do you use? I am using Diamond Crystal."

 

 

I use the cheapest grade I can find, usually sundried sea water. It has a considerable amount of dissolved calcium and magnesium contamination, besides the visible sand, gravel and rust scale that somehow got into the mix of salt crystals. Then again, even high priced, "purified" salt water pool salt showed signs of calcium and magnesium, so I figured why waste the money?

 

WSM B)


Edited by WSM, 23 September 2021 - 07:43 AM.


#5353 WSM

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Posted 03 October 2021 - 07:17 AM

I see. I used that same procedure when I started out using crap expensive food grade salt. It had calcium silicate in it as anti-cake which was a pain to filter off. I noticed treating it with NaOH caused additional calcium silicate to come out of solution (along with anything else) and it made the calcium silicate easier to filter because it consolidated into fluffy web like structures. I used HCl to neutralize after.

What brand of softener do you use? I am using Diamond Crystal.

I do still get white precipitate on the cathodes that needs to be brushed off after a while, but I got that even with the purification step when using the food grade salt.

 

 

In my research, I discovered that sodium carbonate solution, when made from dry sodium carbonate , is highly alkaline due to part of it also forming some hydroxide. The carbonate is used to "soften" hard water, i.e., drop out the minerals as precipitates, which is what we want. After filtering the fine, white precipitates of magnesium and calcium (plus whatever else drops out), the (alkaline) purified brine can then be neutralized with dilute hydrochloric acid and be ready for use as an electrolyte or reacting with other salts, as in the case of potassium chloride solution in sodium perchlorate solution, to drop out potassium perchlorate!

 

The latest episode of Homegrown Oxidizers (Part 18) has been languishing on my computer desktop for years, waiting for me to get back to purifying my KCl solution (and getting photos to add and document the efforts) in the process of making KClO4 equal to or better than that made by industrial suppliers. 

 

I plan to submit the finished articles to the PGI Bulletin for publication, but my continuing research is usually posted in this blog piecemeal as I collect my thoughts for the articles. 

 

WSM B)

 

Edit: The white ppt on the titanium cathode plates or mesh can be anything contaminating the electrolyte, but I suspect it may just be titanium salts (oxides, etc.), though cathodic protection is meant to prevent that.

 

If it doesn't interfere with the chlor-alkali process, don't worry about it. But, if it does interfere, scrubbing it off the cathodes with abrasives between runs may be called for.


Edited by WSM, 03 October 2021 - 07:27 AM.


#5354 WSM

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Posted 05 November 2021 - 07:47 AM

Happy Guy Fawkes night to our friends in the UK.

WSM B)

#5355 Arthur

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Posted 06 November 2021 - 03:55 AM

The sky has been rent asunder on Friday night, Parties may also be held in the Saturday after (6th this year) let's see what tonight brings.



#5356 WSM

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Posted 15 November 2021 - 08:19 AM

FYI: This morning I recalled an interesting note from my studies of home oxidizer production years ago, that I'm passing along.

 

I remember measuring the Voltage, Current and Temperature of my cell runs using digital meters connected to sensors (compatible with the horrible environment of the cell electrolyte).

 

The current level was common throughout the cell but the voltage varied depending on where it was measured from in the circuit. A friend and fellow amateur electrochemist suggested I move the voltage measurement point from the power supply to the connection point at the cell.

 

When I had done so I saw a distinct difference in the voltage reads, which helped me to more accurately determine the actual cell voltage (and more accurately determine the cell end-of-run time)!!!

 

Besides this benefit, I also learned not to exclusively trust the meters on certain power supplies, but having separate digital meters external to the PSU helps to confirm reads and may also show interesting discrepancies in reads between the two.

 

I found it useful to use Teflon coated thermal sensors in the harsh cell electrolyte during the run, for consistent accuracy.

 

WSM B)



#5357 Andead

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Posted 17 November 2021 - 12:31 PM

Hi, Ive managed to obtain a pool chlorinator Cell that has a LOT of plates. Its been previously used so Im unable to tell which is Titanium and which is MMO. Should i presume that the outer plates are the Ti ones or I will need to somehow test. Also , Ive tried using it at 5V and outputting circa 5amps however the anode is flaking alot, are these cells designed for extremely low current or I should proceed as I am going? 



#5358 WSM

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Posted 21 November 2021 - 08:35 AM

Hi, Ive managed to obtain a pool chlorinator Cell that has a LOT of plates. Its been previously used so Im unable to tell which is Titanium and which is MMO. Should i presume that the outer plates are the Ti ones or I will need to somehow test. Also , Ive tried using it at 5V and outputting circa 5amps however the anode is flaking alot, are these cells designed for extremely low current or I should proceed as I am going? 

 

 

I've never worked with a pool chlorinator, but I've had considerable experience (as an amateur) making and using MMO and titanium electrodes.

 

I've heard that some pool chlorinators use MMO on titanium exclusively, which seems odd to me. The only justifications I can see for that is either running the system on alternating current, or the ability to reverse the polarity of the cell intermittently (for some perceived benefit I'm unaware of).

 

If the pool electrodes were removed due to failure, they may be seriously compromised/damaged. MMO is chemically very tough and can withstand a lot of abuse if the conditions are right. Try soaking the plates in pool acid (hydrochloric acid) for 2-12 hours and see if they "clean up" and look or work better. I've used that method to clean brown smut off of used MMO electrodes in the past.

 

Be aware that reverse polarity on an MMO/titanium electrode set can be damaging to the integrity of the MMO, according to some reports (I haven't tried it myself but it may be true).

 

Can take a photo of the unit and post it for us to see? Perhaps there is something in the appearance of it which would help better diagnose the issues you are observing.

 

WSM B)

 

Edit: If you have a good microscope, the condition of clean MMO can be investigated more easily. New MMO has a "cracked mud" appearance and used MMO has a similar but damaged look on a microscopic level.


Edited by WSM, 21 November 2021 - 08:49 AM.





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