making potassium (per) chlorate

[Powderman]

I took a look at solubility of Na and K persulfate and it is easy to make K persulfate from Na persulfate (which seems to be more available) the same way K chlorate is made from Na chlorate. I have found it in an e-shop as etching solution for printed circuits. But using Na persulfate in potassium chlorate cell is no big deal - more Na is probably contained in technical grade KCl. For use in blue stars the chlorate should be at least one or two times recrystallized.
H2O2 at most makes some bubbles and it is gone... For additive to be useful it has to be persistent in the cell and able to aid the wanted reactions or block unwanted ones.

[Arthur]

Sometimes, in the arcane world of electochemistry odd things happen. One of the soluble brighteners to make metals plate directly to a shiny bright finish was simply sugar. There was no logical reason why, but it did work so people used it. Of course the chemical manufacturers had to make something better or they would lose business.

[cmjlab]

Thanks Powderman / Arthur - that is certainly helpful for me to understand better. I will gladly admit that from the pages and pages I've read on persulfate, it's biggest benefit is it's unique ability to not only persist longer than H202 can, but it also seems to thrive or "activate" in the presence of Iron (III) Oxide and/or Manganese effectively enhancing it's beneficial effects. But I imagine you will be using distilled water, without the Fe/Mn. Edited March 1, 2023 by cmjlab

[cmjlab]

Let us know how it works. It's certainly widely available near me as a spa water treatment chemical.

[cmjlab]

Even better I believe it's Potassium Monopersulfate.

[mx5kevin]

After NaClO4+KCl double displacement reaction when recycling old electrolyte the perchlorate contamination it didn't cause any problems for anyone with MMO anodes? In perchlorate cells chlorides highly erode perchlorate anodes too. Sodium chloride contaminated with perchlorate is obtained. When I tried to recycle the solution, I found that it was too erosive. Production Of Potassium perchlorate * By CLIFFORD A. H A M P E L AND P. W . LEPPLA recycling the solution back to the NaClO3 process. But plenty of documentation says that even platinum is severely damaged by this. I currently trying use hot KClO3+NaClO4 solutions and hot filtering see patent CN102807192A Potassium perchlorate production technology with zero wastewater discharge and products thereof. I can make it in half the time the KClO3 than the NaClO3 (1 week vs 2), and NaClO3 -> NaClO4 conversion are faster. But I see that at home everyone using the KCl+NaClO4 reaction. This didn't cause any problems for anyone? MMO anode shows signs of damage after several uses or not? This is a problem in industry, in amateur groups there are not too much feedbacks.

[WSM]

After NaClO4+KCl double displacement reaction when recycling old electrolyte the perchlorate contamination it didn't cause any problems for anyone with MMO anodes? In perchlorate cells chlorides highly erode perchlorate anodes too. Sodium chloride contaminated with perchlorate is obtained. When I tried to recycle the solution, I found that it was too erosive. Production Of Potassium perchlorate * By CLIFFORD A. H A M P E L AND P. W . LEPPLA recycling the solution back to the NaClO3 process. But plenty of documentation says that even platinum is severely damaged by this. I currently trying use hot KClO3+NaClO4 solutions and hot filtering see patent CN102807192A Potassium perchlorate production technology with zero wastewater discharge and products thereof. I can make it in half the time the KClO3 than the NaClO3 (1 week vs 2), and NaClO3 -> NaClO4 conversion are faster. But I see that at home everyone using the KCl+NaClO4 reaction. This didn't cause any problems for anyone? MMO anode shows signs of damage after several uses or not? This is a problem in industry, in amateur groups there are not too much feedbacks.

 

 

I haven't yet tried recycling the electrolyte from the sodium perchlorate/potassium chloride exchange, so I have no information regarding MMO harm/damage problems.

 

It has been reported HIGH levels of chlorides in a perchlorate cell using platinum anodes, damages the platinum, and should be avoided. Considering the cost of platinum metal, it seems to be sound advice.

 

In my experience, making sodium perchlorate from sodium chlorate worked quite well using either platinized titanium or lead dioxide on titanium anodes with titanium cathodes (I did two cell runs, one with each type of anode, to compare them). My research prompted me to run the small experimental cells with low current densities (compared to reported commercial voltage and current levels) due to statements from others of damage to Chinese made LD anodes. I assumed they were run with higher voltages and currents, which caused them to be compromised (falling apart during the attempted operation).

 

I ran my small cells at roughly 4-4.5 Vdc and at a current density between 1.0 and 2.0 Amps per square centimeter. The cell volumes were about 3 liters each and had a distinct ozone odor at the vent tube, but the level of ozone production was low enough not to be an issue (I describe the odor as a "fresh air" smell and not overpowering). No chlorine odor was detected at all.

 

I had only 8 pounds(<4 Kilos) of commercial sodium chlorate for the perchlorate cell electrolyte, and no source to replace it when it was used up (which motivated me to research sodium chlorate production afterward).

 

I ran into issues with my research and have made little progress since 2016, but I haven't given up. I've been busy with other projects and fully intend to continue my research when things slow down. My notes here will continue as I make further progress...

 

WSM

Edited August 3, 2023 by WSM

[WSM]

Professionally a chlorate cell is pH controlled by topping up with a brine/hydrochloric acid mixture. As the cell works brine is consumed and acid is consumed.

 

 

As to the use of persulfates, I have no experience. I am more prone to using things that don't add anything not already in the chlorate or perchlorate cells. I prefer to avoid contaminants for a purer end product(s).

 

Sulfuric acid or sulfates aren't things I'd want in my products or solutions.

 

WSM

 

Edit: When purifying sodium perchlorate (removal of residual chlorate) before exchanging with potassium chloride solution (to make the end product, potassium perchlorate), I've used a solution of sodium metabisulfite to break down chlorates to chloride (leaving the sodium perchlorate solution chlorate-free). This process DOES add sulfate to the solution.

 

Before being able to reuse the "depleted" electrolyte, I reasoned that removal of sulfides or sulfuric acid was possible by treating that electrolyte with calcium chloride solution which would precipitate low-solubility calcium sulfate, which then could be removed with a vacuum filtration setup before recharging the brine with more sodium chloride.

 

One would want to be sure to remove any residual calcium from the electrolyte before running the sodium chlorate cell with the recovered electrolyte (I've been told that calcium chlorate would be a dangerous contaminant and should be avoided).

 

The economy of recovering spent electrolyte on such a small scale usually isn't worth the effort, so it is safely disposed of instead.

Edited July 30, 2023 by WSM

[WSM]

As to the use of persulfates, I have no experience. I am more prone to using things that don't add anything not already in the chlorate or perchlorate cells. I prefer to avoid contaminants for a purer end product(s).

Sulfuric acid or sulfates aren't things I'd want in my products or solutions.

WSM

 

Edit: When purifying sodium perchlorate (removal of residual chlorate) before exchanging with potassium chloride solution (to make the end product, potassium perchlorate), I've used a solution of sodium metabisulfite to break down chlorates to chloride (leaving the sodium perchlorate solution chlorate-free). This process DOES add sulfate to the solution.

Before being able to reuse the "depleted" electrolyte, I reasoned that removal of sulfates or sulfuric acid was possible by treating that electrolyte with calcium chloride solution which would precipitate low-solubility calcium sulfate, which then could be removed with a vacuum filtration setup before recharging the brine with more sodium chloride.

One would want to be sure to remove any residual calcium from the electrolyte before running the sodium chlorate cell with the recovered electrolyte (I've been told that calcium chlorate would be a dangerous contaminant and should be avoided).

The economy of recovering spent electrolyte on such a small scale usually isn't worth the effort, so it is safely disposed of instead.

 

Edit: See correction in color above.

[WSM]

I ran into issues with my research and have made little progress since 2016, but I haven't given up. I've been busy with other projects and fully intend to continue my research when things slow down. My notes here will continue as I make further progress...

WSM

 

 

Well, as life continues and gets more complicated, my energies are focused on improving my home and paying it off, preparatory to retirement, so my electrochemical research has been on hiatus. I absolutely plan to continue my research and writing, going forward.

 

One of my current projects is completing an off-grid solar project (I'm very close) for, among other things, a free (after infrastructure expenses and effort) power source for the next 15+ years. I can see making chlor-alkali oxidizers for little more than the cost of salt and effort, once everything is in place.

 

WSM

[WSM]

One of my current projects is completing an off-grid solar project (I'm very close) for, among other things, a free (after infrastructure expenses and effort) power source for the next 15+ years. I can see making chlor-alkali oxidizers for little more than the cost of salt and effort, once everything is in place.

WSM

 

 

My solar project is an off-grid system ("free" electricity) which will afford me the ability to run a chlorate and perchlorate system for low cost. It can also provide a continual source of pure distilled/de-ionized water, by use of a higher-end dehumidifier which automatically dumps pure condensate periodically into a float-switch-controlled reservoir (to prevent an overflow). I can also use pumps to move the water to wherever it's needed. Lot's of potential!

 

I see exciting times ahead ! More later...

 

WSM

Edited November 18, 2023 by WSM

[WSM]

After running my solar experiment successfully for a short time, I was compelled by a City Inspector, to remove the panels because I failed to obtain a permit for it. I wasn't aware a permit was required for an off-grid installation until after I set it up.

I opted to remove the offending panels rather than invite official snooping into my private pursuits.

If I am able to install an off-grid PV system on my home, I will follow that course and feed my workshop from the power produced thereby. We shall see...

WSM

Edited March 24 by WSM
clarity

[mx5kevin]

NaClO4+KClO3=KClO4+NaClO3 CN102807192A Potassium perchlorate production technology with zero wastewater discharge and products thereof. I ran into a few problems that seem to have been fixed. The first problem is to keep the chlorate in solution so that the perchlorate precipitates most efficiently. I calculated a 73g/l saturated KClO3 solution at room temperature what are calculated to the current NaClO4 cell size. First the NaClO4 cell with the solution are filtered from all insoluble impurities. Than in hot minimum 90°C cell solution dissolved the KClO3 and cooled down in the cell and filtered the KClO4. After this reaction the NaClO3 are converted back to NaClO4 which is very fast using electrolysis. The process can be repeated indefinitely, only sometimes the NaClO3 must be refilled. If this is repeated twice with the crystals, using as clear as possible NaClO4 the chlorate separates nicely from the perchlorate. The process does not require a procedure that causes unnecessary material loss. Based on the experiments so far, it is much better than a KCl+NaClO4 reaction especially for the price/value ratio. I found a big disadvantage is that potassium separates on the anode and therefore causes deposits in the perchlorate cell in the case of a lead dioxide. By cooling the cell solution to around 0°C, the potassium can be easily separated, but the problem is that if lead dioxide is used, there will be a KClO4 deposit on it. I recommend the method to those who prepare chlorates and perchlorates with a single platinum clad electrode. In the case of sodium, I found that it takes at least twice as much time to convert from chloride to chlorate as it does for potassium (with a single platinum). And converting NaClO3 to NaClO4 so much time than converting KCl to KClO3 (with a single platinum).

[mx5kevin]

For those of you who want a long-term Platinum elecreode, here is one that has worked for me for more than 10 years. MMO, PbO2, Platinized titanium anodes none of them last long. There were those who planned to make it at home PbO2 and another anodes, GSLD anodes (for perchlorate) as I read with the feedback, it was disastrous for those who tried it. And for chlorates manganese dioxide anodes  users report bad success. Working homemade PbO2 perchlorate anodes require a minimum of titanium base  that is secondary that is ATO or MMO coated. Those who knew how to do it, only sucessed with expensive, difficult professional equipment. So if a beginner says that he will simply make an anode for chlorates and perchlorates cheaply, I recommend that he forget this plan because it won't work. An additional advantage is that the electrode does not require precise pH control, an overdose of acid does not cause problems for the electrode.

You have to buy this once, after that it will serve you practically for a lifetime, if it is sold to someone later, it will  serve him permanently too.

The big one is a graphite cathode, I recommend 10 mm thick (made from a copper coated carbon welding rod). It had a thin copper layer that was simply pulled off like peeling an onion. In the picture this is 6mm, possible to buy 8mm size too. The smaller second bright is the platinum anode 70x3mm silver x0,2mm (200micron pure platinum), closing the entire anode at both ends with platinum.

 

My electrode parameters: 3x70mm silver rod x0.2mm pure platinum, the entire rod is coated with high purity platinum which is suitable for laboratory purposes. It cannot be produced with a weaker electrode than this! Both ends of the platinum electrode are thoroughly sealed with platinum, there is no free silver part.

 

Minimum requirements (my setup) for 400-2000ml setup (slower production 3week NaCl->NaClO4 direct conversion in a pH controlled 400ml cell):

Minimum size: 3x70mm silver rod x0.2mm pure platinum, the entire rod is coated with platinum

Summary:

 Silver weight: approximately 5.18 grams

 Platinum weight: approximately 3.05 grams

Required a 6V 4A power supply (like a cheap car battery charger)

 

Maximum size: 5x70mm silver rod x0.2mm pure platinum, the entire rod is coated with platinum

Summary:

Silver weight: approximately 14.4 grams

Platinum weight: approximately 4.94 grams

Required a 6V 8A power supply (like a cheap car battery charger)

The second price is almost double that of the first basic electrode.

Required cathode a 10mm cheap carbon welding rod (these are coated with copper, but so thin that it can be peeled off with a knife like a Onion).

Manufacturers specializing in laboratory platinum electrodes can make it for you. Both electrodes can be manufactured at a reasonable but not cheap price. This anode required high purity platinum which is suitable for laboratory purposes (and not jewelry platinum).

[WSM]

On 9/11/2024 at 7:58 AM, mx5kevin said:

NaClO4+KClO3=KClO4+NaClO3 CN102807192A Potassium perchlorate production technology with zero wastewater discharge and products thereof. I ran into a few problems that seem to have been fixed. The first problem is to keep the chlorate in solution so that the perchlorate precipitates most efficiently. I calculated a 73g/l saturated KClO3 solution at room temperature what are calculated to the current NaClO4 cell size. First the NaClO4 cell with the solution are filtered from all insoluble impurities. Than in hot minimum 90°C cell solution dissolved the KClO3 and cooled down in the cell and filtered the KClO4. After this reaction the NaClO3 are converted back to NaClO4 which is very fast using electrolysis. The process can be repeated indefinitely, only sometimes the NaClO3 must be refilled. If this is repeated twice with the crystals, using as clear as possible NaClO4 the chlorate separates nicely from the perchlorate. The process does not require a procedure that causes unnecessary material loss. Based on the experiments so far, it is much better than a KCl+NaClO4 reaction especially for the price/value ratio. I found a big disadvantage is that potassium separates on the anode and therefore causes deposits in the perchlorate cell in the case of a lead dioxide. By cooling the cell solution to around 0°C, the potassium can be easily separated, but the problem is that if lead dioxide is used, there will be a KClO4 deposit on it. I recommend the method to those who prepare chlorates and perchlorates with a single platinum clad electrode. In the case of sodium, I found that it takes at least twice as much time to convert from chloride to chlorate as it does for potassium (with a single platinum). And converting NaClO3 to NaClO4 so much time than converting KCl to KClO3 (with a single platinum).

 

 I've only given the patent a cursory view but it shows promise. I like the option of double exchanging the sodium and potassium salts where everything is usable. It will require heating the potassium chlorate to increase solubility, but the reusing of aqueous solutions to avoid creating waste water is a huge benefit!

This certainly bears further study.

WSM

 

Edited September 15 by WSM

[WSM]

1 hour ago, mx5kevin said:

For those of you who want a long-term Platinum elecreode, here is one that has worked for me for more than 10 years. MMO, PbO2, Platinized titanium anodes none of them last long. There were those who planned to make it at home PbO2 and another anodes, GSLD anodes (for perchlorate) as I read with the feedback, it was disastrous for those who tried it. And for chlorates manganese dioxide anodes  users report bad success. Working homemade PbO2 perchlorate anodes require a minimum of titanium base  that is secondary that is ATO or MMO coated. Those who knew how to do it, only sucessed with expensive, difficult professional equipment. So if a beginner says that he will simply make an anode for chlorates and perchlorates cheaply, I recommend that he forget this plan because it won't work. An additional advantage is that the electrode does not require precise pH control, an overdose of acid does not cause problems for the electrode.

 

You have to buy this once, after that it will serve you practically for a lifetime, if it is sold to someone later, it will  serve him permanently too.

 

 

The big one is a graphite cathode, I recommend 10 mm thick (made from a copper coated carbon welding rod). It had a thin copper layer that was simply pulled off like peeling an onion. In the picture this is 6mm, possible to buy 8mm size too. The smaller second bright is the platinum anode 70x3mm silver x0,2mm (200micron pure platinum), closing the entire anode at both ends with platinum.

 

 

 

My electrode parameters: 3x70mm silver rod x0.2mm pure platinum, the entire rod is coated with high purity platinum which is suitable for laboratory purposes. It cannot be produced with a weaker electrode than this! Both ends of the platinum electrode are thoroughly sealed with platinum, there is no free silver part.

 

 

 

Minimum requirements (my setup) for 400-2000ml setup (slower production 3week NaCl->NaClO4 direct conversion in a pH controlled 400ml cell):

 

Minimum size: 3x70mm silver rod x0.2mm pure platinum, the entire rod is coated with platinum

 

Summary:

 Silver weight: approximately 5.18 grams

 

 Platinum weight: approximately 3.05 grams

 

Required a 6V 4A power supply (like a cheap car battery charger)

 

 

 

Maximum size: 5x70mm silver rod x0.2mm pure platinum, the entire rod is coated with platinum

 

Summary:

Silver weight: approximately 14.4 grams

 

Platinum weight: approximately 4.94 grams

 

Required a 6V 8A power supply (like a cheap car battery charger)

 

The second price is almost double that of the first basic electrode.

 

Required cathode a 10mm cheap carbon welding rod (these are coated with copper, but so thin that it can be peeled off with a knife like a Onion).

 

Manufacturers specializing in laboratory platinum electrodes can make it for you. Both electrodes can be manufactured at a reasonable but not cheap price. This anode required high purity platinum which is suitable for laboratory purposes (and not jewelry platinum).

 

That is a nice setup, mx5kevin.

For a perchlorate anode, I've considered using some pure platinum bullion, spot-welded to a copper-filled tubular titanium lead, plus CP titanium for a cathode; to do long term perchlorate production. Yes, the initial outlay would be expensive, but with careful view of the pH and chloride levels, I expect it would produce a lot of perchlorate and last for a long time.

To make chlorates, commercial MMO appears to be the most practical and paired with titanium cathodes plus pH control are the best options to date.

For my purposes, I like doing the chlorate and perchlorate steps separately, allowing purification steps between them, in hopes of getting a purer end product thereby. I also believe proper purification of the starting materials (and other materials used throughout the process, plus good lab techniques) can yield end products as good or better than commercial oxidizers.

"Reagent grade" home grown oxidizers, anyone...?!

WSM

Edited September 15 by WSM

[cmjlab]

1 hour ago, WSM said:

Reagent grade" home grown oxidizers, anyone...?!

WSM

Yes please!  I've followed your experiments closely and considered my own set up at one point.  If nothing else, it makes me appreciate being able to buy it!  I'm not sure I'd have the time to build Pyro with all the work, maintenance, equipment,  etc that goes into making any decent amount of chlorate!  

OTOH, I'm glad it's documented here so I can make it if laws change (which isn't far out of being a possibility)

[Arthur]

Given that a chlorate cell needs to run at 40C or above, will it self heat from the electrolysis current or will it need a heater?

[mx5kevin]

54 minutes ago, Arthur said:

Given that a chlorate cell needs to run at 40C or above, will it self heat from the electrolysis current or will it need a heater?

There is no such requirement at homemade setup. If the electrolysis works, the reaction takes place even at 20°C. It is best to run such a cell outdoors because poisonous corrosive gases are continuously released from it, it is enough if only the power supply is in the building. In winter and summer, the outside temperature differs drastically, it cannot be kept at a fixed constant temperature, but it will work. A bucket on it, then cover up, and it doesn't need anything else. It will still work if it's covered in snow in winter. Potassium does not like it because when it cools below 20°C the crystals precipitate, but with sodium there is no such problem. How fast the reaction will be depends on the surface of the electrodes and the amperes. Of course, you must not overheat the cell, as this will also destroy fast way the electrode especially for a perchlorate cell. It should also be noted that the electrodes can absorb more amperes than the power supply can sustain stable way. For electrodes with a large surface area, a precisely adjustable minimum 10A laboratory power supply is recommended.

Edited September 17 by mx5kevin