Sodium chlorate cell questions.

[markx]

Better assume 50% efficiency..... youll be closer to reality. Considering the amount of time and effort spent on the separation and extraction you may find it rewarding to not start with a too dilute solution of perchlorate. You can check on the progress with KCl solution. Percipitate a sample of the cell liqour on a regular basis and you can assume the approximate state of conversion from the amount of KClO4 formed. With some experience even a visual examination can tell you how close you are to completion. The potassium perchlorate sedimentation looks radically different compared to chlorate. It is instantaneous and superfine, you will know when you see it happening. A saturated sodium chlorate solution that has been nearly completely turned into perchlorate shall form so much percipitate upon adding saturated KCl solution that it forms a muddy mass without any liquid phase over it. You will have to add water to actually examine the amount of potassium perchlorate formed. Edited December 25, 2019 by markx

[THEONE]

Better assume 50% efficiency..... youll be closer to reality. Considering the amount of time and effort spent on the separation and extraction you may find it rewarding to not start with a too dilute solution of perchlorate. You can check on the progress with KCl solution. Percipitate a sample of the cell liqour on a regular basis and you can assume the approximate state of conversion from the amount of KClO4 formed. With some experience even a visual examination can tell you how close you are to completion. The potassium perchlorate sedimentation looks radically different compared to chlorate. It is instantaneous and superfine, you will know when you see it happening. A saturated sodium chlorate solution that has been nearly completely turned into perchlorate shall form so much percipitate upon adding saturated KCl solution that it forms a muddy mass without any liquid phase over it. You will have to add water to actually examine the amount of potassium perchlorate formed.

I really have no idea what is the efficiency of a perch cell, is that low like 50 % ? I thought it was only that low of chlorate cell w/o ph control.

[markx]

In my setup I’ve gotten about 50+% as the generic ballpark efficiency for perchlorate electrosynthesis using Ti substrate Pt anodes. That’s using 4,2-4,5V across the cell and low anodic current densities (about 100mA/cm2). Your system might show a different outcome. Perchlorate formation on Pt is not really a straightforward and well understood process. According to some sources plated Pt does not produce any perchlorate at all. Also it is generically agreed that a voltage in excess of 5V is required across the cell. Both of these statements I’ve found to be untrue in practice. What I’ve also noticed is that there is a conciderable delay in the perchlorate formation process and depending on good fortune it can take between 24-48 hours of electrolysis before formation of perchlorate abruptly starts.

[WSM]

I am afraid to run the cell even more because i may damage the MMO. I am quite sure that the electrolyte is saturated with naclo3

 

Though MMO can be physically damaged by rough handling, it is chemically very tough. By running it in normal cell conditions, it should hold up very well.

 

Also, though MMO is very tough chemically, some compounds CAN destroy it. Fluoride will severely damage the titanium substrate, causing an electric separation from the coating, and this can happen very quickly (in hours)! Other compounds can coat the MMO, preventing it from acting on the electrolyte.

 

If you learn the details of MMO and use common sense, your electrodes will usually survive most things you subject them to.

 

My experience with them is based on marine grade electrodes, which will work in even low chloride cells without harm. Your milage may vary...

 

WSM

Edited December 26, 2019 by WSM

[WSM]

I really have no idea what is the efficiency of a perch cell, is that low like 50 % ? I thought it was only that low of chlorate cell w/o ph control.

 

50% is typical of pH uncontrolled chlorate cells, but I believe a perchlorate cell (sodium chlorate to sodium perchlorate) is more efficient (and faster).

 

WSM

Edited December 30, 2019 by WSM

[WSM]

In my setup I’ve gotten about 50+% as the generic ballpark efficiency for perchlorate electrosynthesis using Ti substrate Pt anodes. That’s using 4,2-4,5V across the cell and low anodic current densities (about 100mA/cm2). Your system might show a different outcome. Perchlorate formation on Pt is not really a straightforward and well understood process. According to some sources plated Pt does not produce any perchlorate at all. Also it is generically agreed that a voltage in excess of 5V is required across the cell. Both of these statements I’ve found to be untrue in practice. What I’ve also noticed is that there is a conciderable delay in the perchlorate formation process and depending on good fortune it can take between 24-48 hours of electrolysis before formation of perchlorate abruptly starts.

 

My experience has shown an immediate production of sodium perchlorate from sodium chlorate electrolyte, when using either platinized titanium or beta-form lead dioxide coated titanium anodes and with titanium cathodes.

 

If running from sodium chloride (which I don't recommend), a delay would be expected before any perchlorate production is seen.

 

WSM

Edited December 28, 2019 by WSM

[THEONE]

I think, i will just assume 100% efficiency at 1st run and see what i got. If it will be close to 100% i will just stay there. If it will be something like 50% i will just calculate everything for 50% efficiency.

[WSM]

I think, i will just assume 100% efficiency at 1st run and see what i got. If it will be close to 100% i will just stay there. If it will be something like 50% i will just calculate everything for 50% efficiency.

 

 

I know the perchlorate cell isn't 100% efficient because my end-of-run electrolyte (mostly sodium perchlorate) has some sodium chlorate remaining, that I've removed by treating the solution with 1M sodium metabisulfite solution, which breaks down the chlorates into chlorides and sulfates, if I remember correctly.

 

After neutralizing the chlorates in the sodium perchlorate solution, the perchlorate can be reacted by exchange with potassium chloride solution, instantly forming fine white potassium perchlorate powder which drops out of solution and can be harvested by vacuum filtration.

 

WSM

Edited December 28, 2019 by WSM

[THEONE]

I am planning to recover Naclo4 with acetone because i can use it for Kclo4 Nh3CLO4 or even hclo4

[markx]

I am planning to recover Naclo4 with acetone because i can use it for Kclo4 Nh3CLO4 or even hclo4

 

It's quite tedious and requires a ton of acetone to purify a sizeable batch of perchlorate using this method. Unless you use a soxlet type of extractor system that recycles the acetone in the process. But then you shall have to really watch out for moisture that may enter the system, as wet solvent shall carry over chlorate impurities and ruin your noble cause. Taking into account the hygroscopic nature of the sodium salt, it becomes quite a pain to properly dry the whole act.

To be honest for KClO4 you really do not have to use meticulously purified sodium perchlorate....I have done the methathesis reaction with straight cell solution from a "complete" perchlorate conversion and provided that one uses excess water and washes the filtrate, it will produce a perfectly functional potassium perchlorate that for practical purposes has no malicious chlorate contamination. In the potassium system the solubility of the chlorate component is vast compared to the perchlorate and practically all of it remains in the solution if an adequate bit of free water is there to accept it.

[WSM]

The hardest contaminant to remove seems to be the sodium residue. If the final product is potassium perchlorate for color stars, removal of sodium contamination is vital.

 

 

WSM

[THEONE]

Something that i thought about Kclo4 production and i wanna hear your opinion. What if i use the naclo3 electrolyte for naclo4 and add a bowl with many small holes on the top of the cell that touch the electrolyte filled with kclo3 ? In theory, kclo3 from the bowl will be consumed and at the bottom of the cell, kclo4 will be ppt right?

Edited December 29, 2019 by THEONE

[Arthur]

Lots of your questions are answered here wikipedia.org/wiki/Solubility_table The least soluble will precipitate first, many salts have a solubility that varies wildly with temperature but sodium chloride has an almost constant solubility. Sodium salts of increasingly oxidised form have increasing solubility but the potassium salts have decreasing solubility.

[THEONE]

Something that i thought about Kclo4 production and i wanna hear your opinion. What if i use the naclo3 electrolyte for naclo4 and add a bowl with many small holes on the top of the cell that touch the electrolyte filled with kclo3 ? In theory, kclo3 from the bowl will be consumed and at the bottom of the cell, kclo4 will be ppt right?

Here is a picture i draw for better understanding. Should this work out? I am thinking maybe Kclo4 formed into kclo3 vessel

Edited December 29, 2019 by THEONE

[WSM]

Lots of your questions are answered here wikipedia.org/wiki/Solubility_table The least soluble will precipitate first, many salts have a solubility that varies wildly with temperature but sodium chloride has an almost constant solubility. Sodium salts of increasingly oxidised form have increasing solubility but the potassium salts have decreasing solubility.

 

Case in point: though the solubility of sodium and potassium chlorides are nearly equal, the solubility of sodium perchlorate is about 100 times the solubility of potassium perchlorate.

 

This means the sodium perchlorate is highly soluble (at least hygroscopic, if not deliquescent), where potassium perchlorate is practically insoluble.

 

This is why potassium perchlorate drops out immediately when potassium chloride solution is quickly added to sodium perchlorate solution.

 

WSM

Edited December 29, 2019 by WSM

[WSM]

Something that i thought about Kclo4 production and i wanna hear your opinion. What if i use the naclo3 electrolyte for naclo4 and add a bowl with many small holes on the top of the cell that touch the electrolyte filled with kclo3 ? In theory, kclo3 from the bowl will be consumed and at the bottom of the cell, kclo4 will be ppt right?

 

 

I'm not sure. A test of the solubility of crystalline potassium chlorate in sodium perchlorate solution would probably answer the question.

 

If you venture to try it, it would be wise to work in small quantities so as to not waste your hard-won sodium perchlorate if it doesn't work. Arthur's post about solubilities is spot on. It's just possible it won't work because the potassium chlorate will resist dissolving in the sodium solutions, but I don't know for sure. If it does work, it may be an uphill battle, again due to the relative solubilities. This all remains to be seen...

 

Let us know if you decide to test your theory, and the results. Thanks.

 

WSM

Edited December 29, 2019 by WSM

[Arthur]

Commercially the sodium salt is electrolysed because it is more soluble so having lots of solute in there is easier on the very expensive electrodes. Electrolysing potassium salts works but at a low rate and with additional wear and damage to the electrodes so it's not viable.

[WSM]

Commercially the sodium salt is electrolysed because it is more soluble so having lots of solute in there is easier on the very expensive electrodes. Electrolysing potassium salts works but at a low rate and with additional wear and damage to the electrodes so it's not viable.

 

That sounds reasonable to me, but if he tries it, we'll know for certain.

 

I recall, all the world was absolutely certain that potassium perchlorate couldn't be produced from potassium chlorate,... till Swede did it. Sure, it wasn't easy and didn't work particularly well, but it does work and not without its problems.

 

Reading about his success and challenges was liberating, as well as informative. His efforts were motivated by an effort to produce perchlorates without ANY sodium contamination. Because of his sharing his experiences, and through further research on my part, I came to the conclusion to pursue research into production of perchlorates by using sodium salts as industry does. In so doing, I've learned so much and been able to make a lot of progress, plus in sharing that here, enabled many amateur electrochemists to understand how they can advance their research and production without "reinventing the wheel". So rather than try to make potassium perchlorate without using sodium salts, I'm working on purifying my potassium perchlorate made with sodium salts. I hope to show that a dedicated amateur can produce high quality oxidizer salts, at least as good as, if not better than what industry does.

 

I'm trying to leave a path for others to follow, to be the person I wish I knew when I got started on this journey. I've stood on the shoulders of those who came before, and hopefully added to the field. The future is bright. If they can do it, so can we!

 

Happy New Year.

 

WSM

Edited December 30, 2019 by WSM

[markx]

Something that i thought about Kclo4 production and i wanna hear your opinion. What if i use the naclo3 electrolyte for naclo4 and add a bowl with many small holes on the top of the cell that touch the electrolyte filled with kclo3 ? In theory, kclo3 from the bowl will be consumed and at the bottom of the cell, kclo4 will be ppt right?

 

Kind of unneccesary to introduce the sodium impurity into the cell if you can straight up start from a potassium system and drive it up to perchlorate stage by electrolysis.

 

Here you can see the visual formation of potassium perchlorate flaking off my diy Pt coated anode (to the right side) in a small potassium perchlorate cell that is running:

 

https://www.youtube.com/watch?v=zD9PlBT1laM

 

The bulk sediment at the bottom is undissolved potassium chlorate that was prepared by electrosynthesis starting from KCl. I made a saturated solution of KClO3 and "some" of it remained undissolved at the cell bottom.

 

So if one desires a sodium free product then it makes sense to start with KCl......turn that into KClO3 by MMO or graphite....then proceed to KClO4 with Pt. No sodium involved in the whole process and no hassle with purification to get rid of it in the end. And I do agree wholehartedly that sodium contamination is a hard case to get rid of to the extent where it does not disturb flame coloration.

 

Also if the direct electrochemical K route proves too much of a hassle then the controlled pyrolysis of KClO3 is a rather quick and simple method to converting coupious amounts of chlorate into perchlorate. Sure the yields are not astronomical, but still reasonable, provided that one works with proper temperature control and does not have detrimental contaminants in the starting chlorate bulk. Ferrous metal compounds, manganese and some other substances do tend to catalyze the thermal decomposition of KClO3 into solely O2 and KCl. But if done under favorable conditions the reaction goes as:

 

4KClO3 -> 3KClO4 + KCl

Edited December 29, 2019 by markx

[WSM]

Kind of unneccesary to introduce the sodium impurity into the cell if you can straight up start from a potassium system and drive it up to perchlorate stage by electrolysis.

Here you can see the visual formation of potassium perchlorate flaking off my diy Pt coated anode (to the right side) in a small potassium perchlorate cell that is running:

https://www.youtube.com/watch?v=zD9PlBT1laM

The bulk sediment at the bottom is undissolved potassium chlorate that was prepared by electrosynthesis starting from KCl. I made a saturated solution of KClO3 and "some" of it remained undissolved at the cell bottom.

So if one desires a sodium free product then it makes sense to start with KCl......turn that into KClO3 by MMO or graphite....then proceed to KClO4 with Pt. No sodium involved in the whole process and no hassle with purification to get rid of it in the end. And I do agree wholehartedly that sodium contamination is a hard case to get rid of to the extent where it does not disturb flame coloration.

Also if the direct electrochemical K route proves too much of a hassle then the controlled pyrolysis of KClO3 is a rather quick and simple method to converting coupious amounts of chlorate into perchlorate. Sure the yields are not astronomical, but still reasonable, provided that one works with proper temperature control and does not have detrimental contaminants in the starting chlorate bulk. Ferrous metal compounds, manganese and some other substances do tend to catalyze the thermal decomposition of KClO3 into solely O2 and KCl. But if done under favorable conditions the reaction goes as:

4KClO3 -> 3KClO4 + KCl

 

 

From reports of those who've tried the pyrolysis of chlorate to perchlorate, the yield didn't live up to the promise. I feel the electrochemical method (preferred by industry) is the most efficient and productive system for us to use, as well. The efforts to set up the cell will ultimately yield the greatest results, in my opinion.

 

WSM

Edited January 1, 2020 by WSM

[markx]

 

 

From reports of those who've tried the pyrolysis of chlorate to perchlorate, the yield didn't live up to the promise. I feel the electrochemical method (preferred by industry) is the most efficient and productive system to use. The efforts to set up the cell will ultimately yield the greatest results, in my opinion.

 

WSM

 

For sure the electrochemical methods are more efficient, especially on an industrial scale....also vastly more captivating. At least they are to me

 

But there are always complications and challenges, whatever method is chosen. Without proper preparation and execution the outcome rarely is excellent. I think it is part of the fun to learn how to master these challenges.

[WSM]

For sure the electrochemical methods are more efficient, especially on an industrial scale....also vastly more captivating. At least they are to me

But there are always complications and challenges, whatever method is chosen. Without proper preparation and execution the outcome rarely is excellent. I think it is part of the fun to learn how to master these challenges.

 

 

I believe the electrochemical method is the most efficient method on an amateur scale as well, and much easier to control. The anode (making it or finding one to buy) is one of the greatest challenges that I see, though access to an effective power supply (one with constant current (CC) capability) can also be difficult, but totally worth the effort.

 

Using a power supply on CC mode helped me to see minor voltage fluctuations that signaled changes in the operation of my sodium perchlorate cell, which clued me onto the proper stopping point in the cell using a platinized titanium anode.

 

The effort required to produce chlorates and perchlorates, has been challenging and captivating. This hobby can really grab you, and if you persist, can lead you to develop skills and insights beyond your imagination.

 

WSM

Edited December 30, 2019 by WSM