making potassium (per) chlorate

[sefrez]

Not sure it was worth it, but I decided to make some titanium electrodes using G1 titanium wire and G2 titanium rod (all I could find.) I used the wire to spot weld a mesh together and spot weld it to a rod. I made two of them to go on either side of a MMO electrode if I make another cell. The titanium wire is 16 gauge by TEMCO. I wanted to make a spot welder and so I did and this is my first "creation" with it. Not sure if the welds will hold up given I didn't do the welds in an inert atmosphere, but with some tests I have made welds that simply don't break, but break adjacent to it, when stressed / bent to that point.

 

 

A spray rubber coat may work well if it doesn't affect the copper.

 

WSM

 

I put a nickel plate on copper contacts I made. Its worked well, though my cell is pretty well closed off (tube letting out gases / mists away from things that may react) so the nickel is not truly being tested. I had one spot to corrode attached to the anode stem where salt creep occurred. I suspect it was driven in anode configuration with respect to the titanium beneath it with the salt / electrolyte. Of course it would have no chance in those circumstances.

[sefrez]

Ok well I put together a chlorate cell using the two titanium cathodes I made with a (claimed to be) iridium / tantalum MMO anode. Jar is made of glass, so it will be good to keep the running cell away from ignition sources and things that can be damaged (or killed) by glass shrapnel. Other than that, I think it may work well. It's air tight under positive pressure way above pressures that would exists in usage with the gas outlet (to be connected to tubing.) That should be a good start preventing salt making its way out.

 

I designed the head and lock ring in 3D modeling software (Fusion 360) and 3D printed it in ABS. Because of the minor porosity in a 3D print (a huge problem in this application) the full surface of each part was sealed with a brushing on of the same ABS plastic dissolved in acetone. I wondered before if ABS plastic would handle the chlorate cell conditions. But I've done this on another cell with many many hours of run time and damage is practically nonexistent. This is a uncontrolled ph environment where the ph tends alkaline and not much chlorine is present in the headspace. I suspect ph controlled conditions may be more harsh (I'm assuming more chlorine would be in the head space under these conditions, but I'm unsure of that.) I'm using nitrile based o-rings for sealing around electrodes which has minor chemical resistance, but they are dirt cheap. If they hold up terribly, maybe I'll get some viton o-rings. The rubber gasket I cut is made from natural rubber. I'm thinking that will fail quickly, but I'm using it now simply for testing. I will need to get another material for this. Maybe something viton aswell.

 

The connectors on the electrodes were made from copper pipe I had. I basically I'm just using pipe as a source of copper sheet metal. Cut a section of pipe -> anneal it -> split it down its length with some cutters -> flatten it out. After the anneal, its very soft and easy to cut / shape. It work hardens as the part is shaped and I've found the final part has reasonable material properties. 10 AWG copper wire was shaped and soldered on, and finally, every thing nickel plated. The high strand count silicone wire is 12 AWG. All this is over kill for what the stem of the anode is going to be able to handle, but it's what I had. Blue cased connector is an EC5 and screws / nuts 304 stainless.

 

Edit: Sorry if photos were rotated 90 degrees in attachment. I don't know why thats happening. Perhaps the form misinterprets the aspect ratio.

Edited March 8, 2021 by sefrez

[WSM]

Ok well I put together a chlorate cell using the two titanium cathodes I made with a (claimed to be) iridium / tantalum MMO anode. Jar is made of glass, so it will be good to keep the running cell away from ignition sources and things that can be damaged (or killed) by glass shrapnel. Other than that, I think it may work well. It's air tight under positive pressure way above pressures that would exists in usage with the gas outlet (to be connected to tubing.) That should be a good start preventing salt making its way out.

 

I designed the head and lock ring in 3D modeling software (Fusion 360) and 3D printed it in ABS. Because of the minor porosity in a 3D print (a huge problem in this application) the full surface of each part was sealed with a brushing on of the same ABS plastic dissolved in acetone. I wondered before if ABS plastic would handle the chlorate cell conditions. But I've done this on another cell with many many hours of run time and damage is practically nonexistent. This is a uncontrolled ph environment where the ph tends alkaline and not much chlorine is present in the headspace. I suspect ph controlled conditions may be more harsh (I'm assuming more chlorine would be in the head space under these conditions, but I'm unsure of that.) I'm using nitrile based o-rings for sealing around electrodes which has minor chemical resistance, but they are dirt cheap. If they hold up terribly, maybe I'll get some viton o-rings. The rubber gasket I cut is made from natural rubber. I'm thinking that will fail quickly, but I'm using it now simply for testing. I will need to get another material for this. Maybe something viton aswell.

 

The connectors on the electrodes were made from copper pipe I had. I basically I'm just using pipe as a source of copper sheet metal. Cut a section of pipe -> anneal it -> split it down its length with some cutters -> flatten it out. After the anneal, its very soft and easy to cut / shape. It work hardens as the part is shaped and I've found the final part has reasonable material properties. 10 AWG copper wire was shaped and soldered on, and finally, every thing nickel plated. The high strand count silicone wire is 12 AWG. All this is over kill for what the stem of the anode is going to be able to handle, but it's what I had. Blue cased connector is an EC5 and screws / nuts 304 stainless.

 

Edit: Sorry if photos were rotated 90 degrees in attachment. I don't know why thats happening. Perhaps the form misinterprets the aspect ratio.

You say the system is positive pressure?!! It is best to run it with a vent to atmosphere with zero positive pressure.

 

For safety, a vent tube on the highest point of the cell lid carries the hydrogen gas (bubbling off the cathodes) up and out of the cell, away from any source of ignition.

 

Otherwise, your setup looks nice.

 

WSM

Edited March 8, 2021 by WSM

[sefrez]

Thanks WSM.

 

As for positive pressure, what I mean is I performed a test whereby I pumped air into the (empty) cell via the gas outlet. The cell in running mode will indeed vent through this and through a tube. There will naturally be a positive pressure due to resistance of gas movement through outlet / tube and bubbler (if used.) But indeed this is negligible compared to the test pressure for leaks.

[Arthur]

I look forward to your report on the suitability of your plastic lid when treated with assorted alkaline HOCl is chemicals. I once used a nylon cable tie and it lasted about two minutes. PVC and PTFE are probably the most suitable plastics but neither are suited to 3d printing afaik.

[sefrez]

According to the chemical resistant charts here:

 

(Nylon) https://www.kelco.com.au/wp-content/uploads/2009/02/nylon-chemical-compatibility-guide.pdf

(ABS) https://www.kelco.com.au/wp-content/uploads/2009/02/abs-chemical-compatibility-guide.pdf

 

nylon appears to be more affected by sodium hypochlorite. For <20%, Nylon = Severe Effect, ABS = Good.

 

I don't see anything on hypochlorous acid and I'm no expert on the chemistry going on in the cell, but wouldn't the HClO species be low in the alkaline solution? I suppose near the anode it could be higher, but the inside of the cell tends to be coated in alkaline solution where I'd think mainly ClO- species (accompanied by Na+ or K+ ions) would exist. If that is the case, perhaps the datasheets above on sodium hypochlorite are applicable here.

[Mumbles]

I think basing it off of sodium hypochlorite is a good first approximation. The cells usually run fairly basic, and hypochlorous acid is not particularly stable on it's own. It should be mostly hypochlorite ion at typical cell conditions. When running a pH adjusted cell, there may be a bit more of it. It's what's responsible for the small burst of chlorine gas when adding HCl to adjust the pH if you don't meter it in. Chlorine gas and sodium hydroxide would be the other two species I'd be concerned about. Based on those resistance charts you posted, I think ABS is the better choice of the two.

[sefrez]

I have run my sell for just over 33 hours at about 9.2 - 9.5 A totalling ~308Ah. Up to the uncertainty of anode surface area I calculated (including my memory), this corresponds to about a 120mA / cm^2 current density. Not being pushed very hard, at least not for initial running and testing.

 

As I predicted, the natural rubber showed signs of deterioration. I have replaced it with silicone for now, because I want to run longer before getting a specialised seal. I predict it will fair better but will probably still be insufficient.

 

The o-rings have lost a little of their shine, which suggests to me micro tearing or pitting. I removed one and and looked for any "macroscopic" tearing, or any ofther unusual material characteristics (like stiffness, crumbling,...) and nothing. I think they will last a while and again are cheap. I'll have to see how things progress.

 

The ABS plastic appears to be ok. There was no salt creeping though seals which made me happy.

 

I do have two questions.

 

1) I have been using platinum for oxidation at the anode in the past for chlorates. This is the first time I have used MMO. Do MMO tend to act as a catylist for the decomposition of hypochlorite? I noticed in braking electodes from voltage source the MMO electrode continues to have gas(es) coming out of solution near it. I don't think it is chlorine (or very little) given no distinct odor apart from what you expect of the bleach containing solution. Possibly oxygen? 2ClO- -> 2Cl- + O2. Note this on an open circuit. The electodes are not connected.

 

2) What should I use for sealing, if rubber? I've seen Viton mentioned in this thread, and in looking at its chemical compatablity, contrary to its good chemical resistance, it has been suggested to not use with hot water / steam. I see different types but between availability and knowing which type, I'm a little at a loss.

 

Thanks.

[WSM]

I have run my sell for just over 33 hours at about 9.2 - 9.5 A totalling ~308Ah. Up to the uncertainty of anode surface area I calculated (including my memory), this corresponds to about a 120mA / cm^2 current density. Not being pushed very hard, at least not for initial running and testing.

 

As I predicted, the natural rubber showed signs of deterioration. I have replaced it with silicone for now, because I want to run longer before getting a specialised seal. I predict it will fair better but will probably still be insufficient.

 

The o-rings have lost a little of their shine, which suggests to me micro tearing or pitting. I removed one and and looked for any "macroscopic" tearing, or any ofther unusual material characteristics (like stiffness, crumbling,...) and nothing. I think they will last a while and again are cheap. I'll have to see how things progress.

 

The ABS plastic appears to be ok. There was no salt creeping though seals which made me happy.

 

I do have two questions.

 

1) I have been using platinum for oxidation at the anode in the past for chlorates. This is the first time I have used MMO. Do MMO tend to act as a catylist for the decomposition of hypochlorite? I noticed in braking electodes from voltage source the MMO electrode continues to have gas(es) coming out of solution near it. I don't think it is chlorine (or very little) given no distinct odor apart from what you expect of the bleach containing solution. Possibly oxygen? 2ClO- -> 2Cl- + O2. Note this on an open circuit. The electodes are not connected.

 

2) What should I use for sealing, if rubber? I've seen Viton mentioned in this thread, and in looking at its chemical compatablity, contrary to its good chemical resistance, it has been suggested to not use with hot water / steam. I see different types but between availability and knowing which type, I'm a little at a loss.

 

Thanks.

 

When the power is off, it's best to remove the electrodes from the cell, rinse them with distilled water and set them aside till used again. Under power in a cell, the MMO electrodes are very tough, but when the power is off, the alkaline electrolyte can cause damage to them.

 

I find that Viton B is very good in harsh environments.

 

WSM

[WSM]

Not sure it was worth it, but I decided to make some titanium electrodes using G1 titanium wire and G2 titanium rod (all I could find.) I used the wire to spot weld a mesh together and spot weld it to a rod. I made two of them to go on either side of a MMO electrode if I make another cell. The titanium wire is 16 gauge by TEMCO. I wanted to make a spot welder and so I did and this is my first "creation" with it. Not sure if the welds will hold up given I didn't do the welds in an inert atmosphere, but with some tests I have made welds that simply don't break, but break adjacent to it, when stressed / bent to that point.

 

 

 

I put a nickel plate on copper contacts I made. Its worked well, though my cell is pretty well closed off (tube letting out gases / mists away from things that may react) so the nickel is not truly being tested. I had one spot to corrode attached to the anode stem where salt creep occurred. I suspect it was driven in anode configuration with respect to the titanium beneath it with the salt / electrolyte. Of course it would have no chance in those circumstances.

 

Nice looking cathode mesh electrodes (at least as far as I can make out the view on a tiny cellphone screen!). Keep up the good work.

 

WSM

[sefrez]

When the power is off, it's best to remove the electrodes from the cell, rinse them with distilled water and set them aside till used again. Under power in a cell, the MMO electrodes are very tough, but when the power is off, the alkaline electrolyte can cause damage to them.

 

I find that Viton B is very good in harsh environments.

 

WSM

 

Nice to know, thanks. I do remove the electrolyte from the cell when not running, but have neglected at times to rinse off remains. I processed out about 120 grams of KClO3 with the MMO and at that point the anode looked untouched indicating no particular problems. Though I decided to process my sodium based solution (already containing plentiful chlorate and chloride) and let it run for 25 hours at 9.2 amps and took things apart to analyze. I'm thinking the anode mesh looks a little different, less shine, but that may be bias on my part because I noticed that the anode stem had corroded a little in the head space where it meets the solution. I'm realizing just now that this observation supports your statement about the alkaline electrolyte causing damage, because, this portion is being wetted by mist and is effectively not in anodic configuration.

 

Are others seeing this?

 

The mesh itself looks fine, although the stem corrosion has caused me to take a closer look and I'm not entirely sure if it has lost shine.

 

Still, I had no issues with the potassium electrolyte. Because of that, I'm thinking there is another variable at play. The potassium electrolyte is relatively knew, where as the sodium electrolyte has had many many hours of run time with the platinum electrode - of course with chloride levels replenished. I use silver nitrate / sodium chromate to determine chloride concentration and try to keep over about 10 g / 100ml which was the case in this last run. The max temperature I read in the run was about 52C. In the potassium electrolyte it was about 47C.

 

I did try to approximate the composition of the sodium electrolyte and came up with the following per 1 ml solution:

0.65 g solid mass, of which:

23% is NaCl,

8% is NaClO4 (probably present from previous runs with Pt electrode),

69% is any other remaining salts (hopefully mainly NaClO3.)

 

One issue with these numbers is they came from measurements following boiling a solution sample dry which would have destroyed any hypochlorite yielding a (potentially quite) different composition than that originally.

 

But I'm primarily interested in that 8% NaClO4. Could the presence of small amounts of perchlorate cause MMO electrode corrosion? I'm thinking of concentrating the electrolyte to the point of salt saturation and adding KCl to precipitate most of the ClO4- as KClO4...

 

As far as viton goes, I ordered some viton "FKM." FKM seems to refer to a class fluoroelastomers. So I have no idea what type they are. On the viton website, I've seen Viton A, Viton B, Viton Extreme (really expensive!), and possibly others...

 

Nice looking cathode mesh electrodes (at least as far as I can make out the view on a tiny cellphone screen!). Keep up the good work.

 

WSM

 

Thanks. If I wasn't bothered to dissolve a beautiful piece of Pt metal, I'd try to make one with a Pt coating. I just can't do it. It's too precious...

[WSM]

Thanks. If I wasn't bothered to dissolve a beautiful piece of Pt metal, I'd try to make one with a Pt coating. I just can't do it. It's too precious...

 

 

I've seriously considered using a gram or two of platinum to make an anode plating solution, if only I could get it for a "reasonable" cost (somewhere at or near the spot price and minus the heavy middle-man markups). The idea of plating platinum is intriguing, especially as the plating layer could be as thick as you want, if you develop the proper system and skills to do so.

 

Maybe, one day...

 

WSM

Edited March 28, 2021 by WSM

[Arthur]

One problem with plating small things is that the metal that has to be in solution is huge compared to the metal that you can transfer to a cathode If you are bothered by $50 of Pt on an electrode you'd certainly need to be bothered by the $500 that will be left in solution when the electrode plating is finished.

[WSM]

One problem with plating small things is that the metal that has to be in solution is huge compared to the metal that you can transfer to a cathode If you are bothered by $50 of Pt on an electrode you'd certainly need to be bothered by the $500 that will be left in solution when the electrode plating is finished.

 

The process I'm considering isn't electroplating but a system similar to that used for making MMO anodes, which has been called "paint and bake".

 

A solution of platinum is painted onto carefully prepared CP titanium and then baked in a kiln till the platinum is deposited on the base metal. The process is repeated until the desired thickness of coating is achieved.

 

There are several details left out but those are the fundamentals of the process.

 

WSM

Edited March 29, 2021 by WSM

[champ739]

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?

[WSM]

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

 

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 June 3, 2021 by WSM

[sefrez]

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. Thoughts?

[Arthur]

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

[WSM]

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

Edited July 20, 2021 by WSM

[WSM]

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

Edited September 20, 2021 by WSM

[AndyPyroNoob]

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://electrodesupply.com/lead-electrode-98-2-x-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.au/itm/274724277245?hash=item3ff6d7cbfd:g:nKMAAOSwdPJgUvU-&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.

 

 

[WSM]

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

[sefrez]

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

 

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://electrodesupply.com/lead-electrode-98-2-x-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.au/itm/274724277245?hash=item3ff6d7cbfd:g:nKMAAOSwdPJgUvU-&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.

[AndyPyroNoob]

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 September 18, 2021 by AndyPyroNoob

[WSM]

 

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

 

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 September 20, 2021 by WSM