making potassium (per) chlorate

[Mumbles]

Vogel is available from the sciencemadness library. http://library.sciencemadness.org/library/books/vogel_practical_ochem_3.pdf

 

Vogel has written several books, but I think that is the one being referenced.

[Arthur]

Vogel wrote his books in the 1920s, He wrote many useful texts. His "Quantitative inorganic analysis" was the book intended. HOWEVER these books have gone through many editions including several still in copyright. If you are serious about this chemistry then a retail purchase would be in order -it pays the authors to keep writing good books.

[WSM]

Vogel wrote his books in the 1920s, He wrote many useful texts. His "Quantitative inorganic analysis" was the book intended. HOWEVER these books have gone through many editions including several still in copyright. If you are serious about this chemistry then a retail purchase would be in order -it pays the authors to keep writing good books.

 

With an internet search, I've found a used hard copy of the book. It was about $33 delivered and it's on its way.

 

WSM

[WSM]

 

Hopefully, I'll have some sodium perchlorate solution soon. The perchlorate cells (one each for platinum and LD anodes) are ready, the sodium chlorate solution is made, the meters are mounted and enclosed in plastic project boxes and all I'm lacking is a decent place to set it all up.

I prefer to work outdoors but need a shelter for the system and especially the electronic and electric components. Things are coming together, but it's slow going. I hope by this time next week, I'll be reporting on my experiences. We'll see...

WSM

 

The LD cell has run to completion and I stopped the run at 71 hours at 15 Amps, constant current. I have some analysis and purification to perform on this batch, but it tests strongly positive for perchlorate.

 

I have to make up a small amount of Indigo carmine reagent to test for chlorate residue plus to help determine when the chlorate has been destroyed by sodium metabisulfite solution. Then I'll have to drop some KCl solution into a sample of the NaClO₄ solution, the observe and record the results.

 

The Chinese lead dioxide anode appears to work very well and according to my expectations in textbook fashion. Unfortunately, I ran the cell a little too long and got a bit of degradation to the anode which manifested as a definate brown tint to the cell liquor in the final two hours it ran. Next time I'll run it no more than 60 hours with similar parameters.

 

WSM

[WSM]

This photo shows the operation as of last night:

 

 

This is the brown coloration seen in the cell electrolyte after the run:

 

 

A disappointing turn of events, but everything ran well till this happened. I'm curious to see how much chlorate is left.

 

We'll see...

 

WSM

[WSM]

I've set up and started running the platinum cell in one of my one gallon (3.785 liter) pickle jars:

 

 

The surface area of the anode is about one third that of the LD anode, so I've dropped the current delivery to 10 Amps, or about 0.2 A per cm², if my calculations are right.

 

I'll report more later...

 

WSM

[Arthur]

From the paper on the Henderson perc plant they used sodium salts for electrolysis then precipitated the perchlorate by adding KCl. If you control how much KCl you add then only that much anion will be precipitated, First the perc comes down then the chlorate, so if you only add enough KCl to ppt the ClO4 the ClO3 stays in solution and is recirculated.

[WSM]

From the paper on the Henderson perc plant they used sodium salts for electrolysis then precipitated the perchlorate by adding KCl. If you control how much KCl you add then only that much anion will be precipitated, First the perc comes down then the chlorate, so if you only add enough KCl to ppt the ClO4 the ClO3 stays in solution and is recirculated.

 

A worthy notion if one is able to accurately determine the mass of perchlorate present. I may have to work on that one when my experience or expertise allows (unless a better option appears).

 

Thanks for the suggestion.

 

WSM

Edited April 18, 2015 by WSM

[WSM]

I've set up and started running the platinum cell in one of my one gallon (3.785 liter) pickle jars:

Platinum Anode Start of Run 1920hr 4-16-15.JPG

The surface area of the anode is about one third that of the LD anode, so I've dropped the current delivery to 10 Amps, or about 0.2 A per cm², if my calculations are right.

I'll report more later...

WSM

 

I tested the liquor after ten hours of running with methylene blue solution:

 

 

The blue spot on the left is sodium chlorate solution (starting electrolyte) and the purple spot on the right is showing a positive test for perchlorate in the electrolyte, after running in the platinum cell for ten hours.

 

This is exciting!

 

WSM

Edited April 18, 2015 by WSM

[Arthur]

If you take some end point electrolyte (your chosen end point just before completion) and add a little KCl, some Kperc will precipitate and can be harvested, add more KCl and more Kperc will come down to harvest etc til all the perchlorate is taken, then K Chlorate will start to come down. As the crystal form is different it's obvious where the change is, but you do have a small batch of mix

 

With intelligence you can "guess" or even graph the perc produced per amp hour and add 95% of it's KCl needs in one shot recover the ppt (Kperc) and return the remaining Na salts and the liquor back to a chlorate cell.

[WSM]

If you take some end point electrolyte (your chosen end point just before completion) and add a little KCl, some Kperc will precipitate and can be harvested, add more KCl and more Kperc will come down to harvest etc til all the perchlorate is taken, then K Chlorate will start to come down. As the crystal form is different it's obvious where the change is, but you do have a small batch of mix

With intelligence you can "guess" or even graph the perc produced per amp hour and add 95% of it's KCl needs in one shot recover the ppt (Kperc) and return the remaining Na salts and the liquor back to a chlorate cell.

 

For production, this method is sound. My view, with the sample batch previously run and the current batch in progress, is exploritory. By using the data gathered plus careful titration-style destruction of the residual chlorate, I hope to determine the chlorate and perchlorate percentages in my end-run solutions.

 

Edit- *Also I want to experiment on making completely sodium-free, pyrotechnics grade potassium perchlorate, suitable for the most demanding color applications. Why not? We've already come this far...

 

Knowing the perchlorate percentage accurately will give me the current efficiency with the parameters of my run (and hopefully establish good numbers to base future runs on).

 

I'm certain my next efforts will be sodium chlorate production to generate feed stock for perchlorate cells. It'll be interesting to compare home made sodium chlorate in a perchlorate cell to the reagent grade material I've used in these tests. Obviously, there's much more work to do.

 

WSM

Edited April 19, 2015 by WSM

[WSM]

This photo shows the operation as of last night:

IMGP7773.JPG

This is the brown coloration seen in the cell electrolyte after the run:

IMGP7779.JPG

A disappointing turn of events, but everything ran well till this happened. I'm curious to see how much chlorate is left.

We'll see...

WSM

 

All is not lost, and patience pays off:

 

This is the way it looked after the run

 

And this is the way it looked after sitting two days

 

I think simple filtering will remove the sediment (which I fear is a lead compound). I plan to test the solid residue and see if I can accurately determine what it is. If it is lead, I'll need to develop proceedures that will minimize, if not eliminate, this from happening in future runs.

 

One thing I noticed in some of my "reagent grade" sodium chlorate, was a bit of residue in the solution . It looked like fine, dark dust particles; and I probably should have filtered the solution before running it in the LD cell. The next batch of sodium chlorate I used (kindly donated by pyrojig, [Thanks]) was much nicer (and I wish he had a 100 pound drum of it!) and made a clean, clear solution; which is running in the Pt cell.

 

Still more to come...

 

WSM

[barzn]

 

For production, this method is sound. My view, with the sample batch previously run and the current batch in progress, is exploritory. By using the data gathered plus careful titration-style destruction of the residual chlorate, I hope to determine the chlorate and perchlorate percentages in my end-run solutions.

 

Edit- *Also I want to experiment on making completely sodium-free, pyrotechnics grade potassium perchlorate, suitable for the most demanding color applications. Why not? We've already come this far...

 

Knowing the perchlorate percentage accurately will give me the current efficiency with the parameters of my run (and hopefully establish good numbers to base future runs on).

 

I'm certain my next efforts will be sodium chlorate production to generate feed stock for perchlorate cells. It'll be interesting to compare home made sodium chlorate in a perchlorate cell to the reagent grade material I've used in these tests. Obviously, there's much more work to do.

 

WSM

It's great to see how much your work is fruitful so far! (and also frustratingly how much it is far more steps ahead from where i'm at..).

Both of your experiments with the Pt and LD gave me much of thoughts and ideas what to improve in my ongoing Chlorate and Perchlorate cells, which are yet to be complete, so thanks for that!

Your setup with the LD anode is quite facsinating. Though it's still impractical for my setup (The lack of some equipment to arrange the electrodes as you did), it did gave me the idea to make the connections for the two Ti cathodes surrounding the LD from outside.

 

With that said, unfortunately for me, now that 3 of my cells setups are near completion (Ru-Ir MMO, Pt and LD - all with Ti cathodes) there is one thing that's really giving me some troubles and a big headache.

It is, ofcouse, my chosen power supply. the current (Na Chlorate) cell i'm trying to run is a 1.5L of solution in a clear PVC container. I do maintain the Temp. and pH at the desirable range with a thermostat and a pH meter constantly attached to the cell.

The solution was made from 700g of NaCl and 2.1L of distilled water (near full saturation), and a few drops of HCl was also added to bring it to a pH of ~6, only 1.5L used.

The power supply is then set to CC of 9.5A and turned on (2X3 inch Ru-Ir anode was used at about .3A per cm2).

 

The problem is that my power supply simply refuses to put out the needed current and voltage. once it is turned on it shuts down and sais OVP (over voltage protection). this is because at 3.6V it will only put out 0.33A, and only once i raise the voltage, the current will also go up, but remains approx. in these ratios. This is a frustrating problem. I should also mention the voltage remains like so regardless of anode-cathode spacing.

I also tried to reduce the resistance of the electrolyte by adding more water, so more current could be sent without the voltage increase that much, but no change.

My power supply is a regulated dc PSU, capable of 0-16Vdc and 0-10A, which works flowlessly with other components (it is new, out of the box).

I can't get the hold of whats wrong here.

this is the power supply:

http://www.aliexpress.com/item/Freeshipping-NEW-precision-Compact-Digital-Adjustable-DC-Power-Supply-OVP-OCP-OTP-low-power-16V10A-110V/1764155414.html

 

I would really appreciate anyones help!

Edited April 19, 2015 by barzn

[THEONE]

I have a questuon, almost all new computer PSUs the biggest output is at 12volts. Can two cells run in series so the current on eatch cell will be 6volts ?

[WSM]

It's great to see how much your work is fruitful so far! (and also frustratingly how much it is far more steps ahead from where i'm at..).

Both of your experiments with the Pt and LD gave me much of thoughts and ideas what to improve in my ongoing Chlorate and Perchlorate cells, which are yet to be complete, so thanks for that!

Your setup with the LD anode is quite facsinating. Though it's still impractical for my setup (The lack of some equipment to arrange the electrodes as you did), it did gave me the idea to make the connections for the two Ti cathodes surrounding the LD from outside.

With that said, unfortunately for me, now that 3 of my cells setups are near completion (Ru-Ir MMO, Pt and LD - all with Ti cathodes) there is one thing that's really giving me some troubles and a big headache.

It is, ofcouse, my chosen power supply. the current (Na Chlorate) cell i'm trying to run is a 1.5L of solution in a clear PVC container. I do maintain the Temp. and pH at the desirable range with a thermostat and a pH meter constantly attached to the cell.

The solution was made from 700g of NaCl and 2.1L of distilled water (near full saturation), and a few drops of HCl was also added to bring it to a pH of ~6, only 1.5L used.

The power supply is then set to CC of 9.5A and turned on (2X3 inch Ru-Ir anode was used at about .3A per cm2).

The problem is that my power supply simply refuses to put out the needed current and voltage. once it is turned on it shuts down and sais OVP (over voltage protection). this is because at 3.6V it will only put out 0.33A, and only once i raise the voltage, the current will also go up, but remains approx. in these ratios. This is a frustrating problem. I should also mention the voltage remains like so regardless of anode-cathode spacing.

I also tried to reduce the resistance of the electrolyte by adding more water, so more current could be sent without the voltage increase that much, but no change.

My power supply is a regulated dc PSU, capable of 0-16Vdc and 0-10A, which works flowlessly with other components (it is new, out of the box).

I can't get the hold of whats wrong here.

this is the power supply:

http://www.aliexpress.com/item/Freeshipping-NEW-precision-Compact-Digital-Adjustable-DC-Power-Supply-OVP-OCP-OTP-low-power-16V10A-110V/1764155414.html

I would really appreciate anyones help!

 

Hi barzn,

 

Try this with your power supply. Set up the load (your cell) and connect everything as it'll be when running. Now before powering up the supply, turn the voltage and current all the way down. Next turn the voltage all the way up. Now switch on the power and slowly turn up the current till it reaches the desired level. It should be in CC mode at this point.

 

Let us know how this works or what problems you see.

 

WSM

[WSM]

I have a questuon, almost all new computer PSUs the biggest output is at 12volts. Can two cells run in series so the current on eatch cell will be 6volts ?

 

Theoretically, you can connect two power supplies in either series (double the voltage) or parallel (double the current); but in practice it's very tricky. Ideally the power supplies need to be perfectly matched before you can even consider doing this. It's even better if the supplies are rated to be connected that way.

 

WSM

[MrB]

 

Theoretically, you can connect two power supplies in either series (double the voltage) or parallel (double the current); but in practice it's very tricky. Ideally the power supplies need to be perfectly matched before you can even consider doing this. It's even better if the supplies are rated to be connected that way.

 

WSM

 

Pssst. He's asking about the opposite, can he run two cells in series, to get half the voltage on each. (Or you were suggesting that he run parallel PSU's to use 5v?)

 

If the resistance is identical, the answer should be yes, but i think it might be hard to match that, so in practice, it might not be feasible.

 

Thats my instant gut reaction to the question anyway. Someone who knows more about electronics.... should have a more fact-based opinion.

B!

Edited April 19, 2015 by MrB

[WSM]

I have a questuon, almost all new computer PSUs the biggest output is at 12volts. Can two cells run in series so the current on eatch cell will be 6volts ?

 

Ah, yes (I misread this). Yes, each cell would be 6 Volts and the current would not drop.

 

If you want to split voltage, a better option would be to run three cells in series, with a voltage drop across each one of 4 Volts (industry averages 3.6 Vdc per cell). In this case (a DC series circuit) the current would be the same in each of the three cells (full current).

 

"the current on eatch cell will be 6volts" This statement is confusing because voltage is electromotive force (electrical "pressure", if you will) and current is the number of (or "volume") electrons, measured in Amperes or Amps.

 

Good Luck.

 

WSM

[WSM]

Pssst. He's asking about the opposite, can he run two cells in series, to get half the voltage on each. (Or you were suggesting that he run parallel PSU's to use 5v?)

If the resistance is identical, the answer should be yes, but i think it might be hard to match that, so in practice, it might not be feasible.

Thats my instant gut reaction to the question anyway. Someone who knows more about electronics.... should have a more fact-based opinion.

B!

 

Yeah, you're right; I goofed. (Nice catch. Thanks)

 

I was referring to paralleling two matching power supplies to double the current output. It's tricky business at best. Typically one of the two supplies will "hog the load" and burn out.

 

WSM

[barzn]

 

Hi barzn,

 

Try this with your power supply. Set up the load (your cell) and connect everything as it'll be when running. Now before powering up the supply, turn the voltage and current all the way down. Next turn the voltage all the way up. Now switch on the power and slowly turn up the current till it reaches the desired level. It should be in CC mode at this point.

 

Let us know how this works or what problems you see.

 

WSM

Dear WSM!

 

No luck here..

Something really strange here, whatever current i set it to, the voltage will remain about 5 times higher. And thats regardless of any other cell parameter. The psu will automatically regulate the current (say 3.6v, the current will be .33A, even if set to 10A).

I have to get past this issue soon..

I figured to reduce the voltage by paralleling 2 or 3 cells (since nothing else does), but im not even sure this will work.

What could be done here?

I have a video describing the isuue if its of any help.

[MrB]

I figured to reduce the voltage by paralleling 2 or 3 cells (since nothing else does), but im not even sure this will work.

 

If you want each cell to see a lower voltage, you need to put them in series. If you put them in parallel, they will see less current, at the current voltage. (phun intended)

 

I'm not really a fan of putting cells in series. Yes, it will let each cell see a lower voltage, but if the resistance of the cells aren't identical, It's going to throw both the voltage, and the current of. And i'm thinking the resistance of a cell depends a lot on where in the cycle it is, and no 2 cells will ever be at the same point, at the same time. With the possible exception for the first 5 seconds after starting them, right after filling with fresh stuff.

 

B!

[barzn]

 

If you want each cell to see a lower voltage, you need to put them in series. If you put them in parallel, they will see less current, at the current voltage. (phun intended)

 

I'm not really a fan of putting cells in series. Yes, it will let each cell see a lower voltage, but if the resistance of the cells aren't identical, It's going to throw both the voltage, and the current of. And i'm thinking the resistance of a cell depends a lot on where in the cycle it is, and no 2 cells will ever be at the same point, at the same time. With the possible exception for the first 5 seconds after starting them, right after filling with fresh stuff.

 

B!

Correct. I meant connecting them one after the other.

I also think its not ideal to run more than one cell at a time, alot of things vary with this configuration. I only suggested it because i could not think of anything else..

Any idea about the issue/thoughts how to solve it?

[MrB]

Any idea about the issue/thoughts how to solve it?

 

Not really, i'm afraid. It's a weird problem to have, since you actually got a PSU that should be suited for this, rather then as most, try to make do with a power-source that has been scavenged from somewhere else.

B!

[schroedinger]

A much easier option is propably to use an older atx power supply. They have the main output at 5 V. Normally from 20 to 40 A. And only 8 to 12 A at 12 V

[WSM]

Dear WSM!

 

No luck here..

Something really strange here, whatever current i set it to, the voltage will remain about 5 times higher. And thats regardless of any other cell parameter. The psu will automatically regulate the current (say 3.6v, the current will be .33A, even if set to 10A).

I have to get past this issue soon..

I figured to reduce the voltage by paralleling 2 or 3 cells (since nothing else does), but im not even sure this will work.

What could be done here?

I have a video describing the isuue if its of any help.

 

Hi barzn,

 

When you set it up does only the CC lamp light up? I'm wondering if the electrodes are too big for the PSU (peak demand ~23.22A)? One test would be to make an anode 25mm x 50mm (peak demand ~7.74A) with matching cathodes and try that with the PSU. Are you able to try that?

 

The worst case is that the PSU is incapable or running an electrochemical cell. Let's hope it's something else.

 

WSM