making potassium (per) chlorate

[WSM]

When adding the NaOH, don't go too high with the Ph or you will actually start to redissolve the metal hydroxide. A Maximum of 9 should be sufficient. (High Ph water treatment is a standard waste treatment for removing metals)

 

From what I've read about the reactions, I might be able to get the job done with the carbonate alone. We'll see...

 

WSM

[taiwanluthiers]

Are you able to search through your history, or at least find some way of narrowing down the matches?

 

I've done a cell with tap water before (when I was in Taiwan no one sells distilled water except in 500mL bottles that cost over a dollar each) and I got those calcium buildup on the cathode... It didn't really create any problem and I simply soak the cathode in HCl to descale it if necessary...

[WSM]

From what I've read about the reactions, I might be able to get the job done with the carbonate alone. We'll see...

WSM

 

According to the Wikipedia reference for sodium carbonate, as an aqueous solution of it is made it forms the hydroxide;

 

"It acts as an alkali because when dissolved in water, it dissociates into the weak acid: carbonic acid and the strong alkali: sodium hydroxide."

 

If this is accurate, adding NaOH with Na₂CO₃ to the brine is redundant. I'll have to try purifying my brine with sodium carbonate solution alone. I'll report the results here.

 

WSM

 

Edit: due to MadMat's caution to avoid a high pH condition, I'll meter the pH of the brine during the purification process to be sure the levels remain in the optimum range (if possible).

Edited May 14, 2016 by WSM

[MadMat]

Add your chem.'s slowly and agitate. Give the Ph time to stabilize before adding more and you should be good. Sodium carbonate is a very weak alkali, although a solution of it can reach rather high Ph's a very small amount of an acid will drop the Ph down (I guess it's called total alkalinity in some circles). If you really want to go crazy, you could get some diphenylcarbazide (solution in alcohol). This is a metal indicator and turns bright pink in the presence of metals in solution. IF you do this, you would want to add a small amount of ammonia to your sample to chelate any copper in solution that would give a false positive. The depth of color created by the diphenylcarbazide is directly proportional to the concentration of the metal dissolved in the solution (I actually designed a colorimetric test protocol for analyzing waste water using diphenylcarbzide when I worked in the lab at a plating company)

Edited May 14, 2016 by MadMat

[WSM]

Add your chem.'s slowly and agitate. Give the Ph time to stabilize before adding more and you should be good. Sodium carbonate is a very weak alkali, although a solution of it can reach rather high Ph's a very small amount of an acid will drop the Ph down (I guess it's called total alkalinity in some circles). If you really want to go crazy, you could get some diphenylcarbazide (solution in alcohol). This is a metal indicator and turns bright pink in the presence of metals in solution. IF you do this, you would want to add a small amount of ammonia to your sample to chelate any copper in solution that would give a false positive. The depth of color created by the diphenylcarbazide is directly proportional to the concentration of the metal dissolved in the solution (I actually designed a colorimetric test protocol for analyzing waste water using diphenylcarbzide when I worked in the lab at a plating company)

 

I have 3M HCl made up and on hand, so I can control the pH with small doses of that. I don't think I have any diphenylcarbazide, so I'll work with what I have on hand.

 

Thanks for the suggestion, though. Do you have any diphenylcarbazide to spare?

 

WSM

[WSM]

To start the purification of the brine for my sodium chlorate cell, I made up some sodium carbonate solution. To make a Molar solution of it takes 105.9888 grams of sodium carbonate per liter of distilled water. Since I don't know how much it'll take I've made a gallon of 1M Na₂CO₃ by adding 401.167 grams of sodium carbonate to an empty jug (used distilled water bottle) and then filling to the top with distilled water.

 

Once it's fully dissolved, I can begin to add it to the brine in a separate bucket (colored so I can see the white precipitate in the bottom), stir and wait. The pH needs to be monitored so it doesn't get too far away from neutral (as MadMat recommended).

 

After the unwanted dissolved salts drop out, I plan to remove them by filtration.

 

I'll show more as this progresses...

 

WSM

[MadMat]

Sorry, I don't have any diphenylcarbazide.

[memo]

now I have 120 hours on my cell. the yellow color has not changed. this is my first run so I am in the dark about a lot of things. how can you tell when you have converted all your sodium to chlorate. I have been running a steady 5 volts and the jar is hot to the touch.

 

memo

[WSM]

now I have 120 hours on my cell. the yellow color has not changed. this is my first run so I am in the dark about a lot of things. how can you tell when you have converted all your sodium to chlorate. I have been running a steady 5 volts and the jar is hot to the touch.

memo

Are you able to measure current (Amps)?

 

If you have an ammeter and measure the current draw of the cell from the beginning, I've usually (with a potassium chlorate cell) shut the system down when the current drops to about 50% of the starting current. Beyond that, a LOT more power is consumed for very small gains.

 

With a sodium system, I'm not experienced enough to know, yet. My studies say the first run will yield no chlorate crystals. They say that after recharging the depleted liquor with chloride and running the second time that the chlorate crystals will start to drop out.

 

I suppose a degree of saturation has to be achieved first.

 

WSM

Edited May 15, 2016 by WSM

[WSM]

Sorry, I don't have any diphenylcarbazide.

 

Too bad. If I get any, I'd like to try the tests.

 

WSM

[Arthur]

The only way to determine the actual progress of the reaction is to titrate samples and determine chlorate and chloride by classical wet analysis say every 12 hours. Search the web for "Quantitative Inorganic Analysis by Vogel" It's the go to book for most of the chemical industry for determining test methods. Early editions may have arrived at second user book vendors near you, current editions will be available from technical book suppliers in your area (country /state /province etc) try a university town.

 

Study Swede's writings and you will find approximations based on current and time.

[WSM]

Study Swede's writings and you will find approximations based on current and time.

 

Swede also developed a flow chart sort of list for determining the "end of run" point in oxidizer electrolysis. It's a one page sheet which looks and feels eerily like an IRS form, but is a good tool to use to figure out when it's time to stop the cell and harvest your product.

 

I've looked through his blogs this morning and can't locate it. It's probably somewhere on his website (5 bears - something), but I didn't look there yet.

 

I'll need that information myself, soon enough, when I get my sodium chlorate cell running.

 

WSM

[WSM]

To start the purification of the brine for my sodium chlorate cell, I made up some sodium carbonate solution.

After the unwanted dissolved salts drop out, I plan to remove them by filtration.

WSM

 

Yesterday I treated about twenty liters of the raw brine with ~350ml 1M sodium carbonate solution, and the whole lot became immediately milky and opaque. This morning I checked it and the precipitates have dropped to the bottom of the bucket, leaving clear brine above.

 

 

Tomorrow, I'll vacuum filter it and put the clear, purified brine into the cell. The pH of the treated brine is about 9, so I'll neutralize it with dilute HCl till it's at or about 7 before placing it in the cell (a slightly lower pH wouldn't hurt).

 

If all goes well, I hope to start the sodium chlorate cell soon.

 

WSM

Edited May 15, 2016 by WSM

[Rkteer]

I would be very interested in that chart by Swede if you find it!

Loving all the info guys

[WSM]

The pH of the treated brine is about 9, so I'll neutralize it with dilute HCl till it's at or about 7 before placing it in the cell (a slightly lower pH wouldn't hurt).

WSM

 

I made a second container of treated brine, so now I'll filter 40 liters instead of 20 (the cell uses about 27 liters if I'm correct). The pH of the second bucket is also about 9. I definitely will neutralize the treated brine after filtering it (and before it goes into the cell).

 

Na₂CO₃ + 2HCl → 2NaCl + CO₂↑ + H₂O

NaOH + HCl → NaCl + H₂O

 

To neutralize any surplus alkali used to purify the brine, some HCl does the job while adding pure sodium chloride. It’s offering a triple benefit;

1. while the contaminants are removed, the brine level is boosted
2. it adjusts the pH to the proper starting levels desired, all while
3. adding nothing foreign to the cell (only things already in there).

Sort of a win-win-win!

 

More later...

 

WSM

Edited May 16, 2016 by WSM

[memo]

i finished my cells run today, the color was still a little yellow. when i boiled the solution it turned brown. dark brown, the a scum forumed on top as it cooled. what is suspect is a stainless pan that i used itt now has brown lines in the bottom that wont scub out. is this batch a lose ?

 

memo

[WSM]

I set up the vacuum filtration system yesterday and ran it with one of the buckets full of treated brine. It worked okay but needs to be refined somewhat (sorry, there aren't photos yet). The trickiest part so far was the vacuum flask.

 

Years ago, a friend (Knowing my chemistry interest) gave me a 5 gallon Pyrex bottle. It has thick walls and a narrow neck but the opening takes a number 12 stopper (which is big enough to handle a few decent sized tubes and still seal). It had to be cleaned because it was stored outdoors. The outside of the bottle was easy enough to clean with running water and a scrubber, but the inside was tougher. A few years worth of rainwater and algae growth needed to be removed. I shook the bottle in a swirling motion and lightly scraped a bit with a stainless tube, and poured most of the gunk out into the grass, but some was persistent.

 

I added high strength (10% solution) sodium hypochlorite and then some pool acid (HCl) and let it sit a few minutes. The fumes filled the rest of the bottle (and I stayed clear due to the toxicity of the cloud inside it). Next, I added some household ammonia and stood back for a few more minutes. After this I added some powdered sodium carbonate to neutralize the acid (plus Na₂CO₃ breaks down in aqueous solutions to some NaOH, as well), and then filled the bottle with water from the garden hose.

 

Next I tested the water with pH paper. The pH then was a little over 7, but low enough not to be a concern so I dumped the water into the flower bed. The bottle came out very clean, or as clean as I could hope for without brushing the inside. I do need to shop at a janitorial supply for longer handled and sized brushes for facilitating such cleaning jobs in the future.

 

The next step involved plumbing all the parts of my super-sized vacuum filtration setup. A few years ago I purchased a non-working laboratory vacuum pump; disassembled and rebuilt it, rinsed and filled it with vacuum pump oil, and use it for most of my vacuum filtration jobs.

 

I'm using a Bel-art benchtop Buchner funnel sized to use 24cm filter paper. Through judicious searching of eBay, I've acquired several boxes of lab grade filter paper for this funnel (most are medium speed, but a couple boxes are slow speed; useful for fine particulates like potassium perchlorate precipitated from NaClO₄ solution).

 

The weak link appears to be the rubber stopper which is green rubber, aged and cracking. I had to very carefully press it tight into the opening of the bottle so it would have enough of a seal that the vacuum filtration would proceed. It did so, but slowly. I searched eBay and found some reasonably priced number 12 rubber stoppers and ordered four. When they arrive, I'll change out the old one and see if the vacuum system works better. I hope so.

 

The last thing I did was test the pH and add pool acid to neutralize the alkali. A final pH range between 6-7 is the goal and was met.

 

The final challenge is to move the purified brine to the cell. Since my chemical handling pumps aren't positive displacement pumps, they aren't self-priming and need head pressure before they'll move the liquid. My purified electrolyte is at a lower elevation, presently and won't move by these excellent pumps till that head pressure is met.

 

i believe my best option is to empty and clean out my brine tank and then fill it with the purified brine. After that's done, I can easily pump the clean brine into the cell without problems. At that point, at last I'll be ready to start the sodium chlorate cell's initial run .

 

WSM

Edited May 18, 2016 by WSM

[WSM]

i finished my cells run today, the color was still a little yellow. when i boiled the solution it turned brown. dark brown, the a scum forumed on top as it cooled. what is suspect is a stainless pan that i used itt now has brown lines in the bottom that wont scub out. is this batch a lose ?

memo

 

Hi memo,

 

Is this batch a loss? Not if it can be filtered and turned clear. Also, you would need to test and determine if any or much unseen contaminants are in there and remove them as well. If you're not equipped to do a laboratory clean-up of this batch, the best solution to the problem would probably be to safely dispose of this batch and start over; learning from the mistakes of the first one and avoid them in the next runs.

 

Don't worry, I think most of us have had rough first attempts (I certainly did), before we refine our system and thinking to overcome these "bumps in the road" and make usable oxidizers.

 

Keep at it, and good luck.

 

WSM

 

Edit: A glass pot (Pyrex or other borosilicate glass) or beaker would probably do better than ANY metal pot for boiling down your electrolyte. I once foolishly poured "depleted" ferric chloride solution (from etching printed circuit boards) into a cheap, stainless steel bowl one night, and the next morning had a terrible mess to clean up. The bowl was turned into a colander due to the many small holes eaten into it by the caustic solution. Another tough lesson learned, stainless steel isn't useful in all situations!

Edited May 17, 2016 by WSM

[Arthur]

1litre of water will dissolve 1390g of sodium chlorate at 60C

 

this is 1390/ 106 = 13.1 moles

 

which comes from 13.1 x 58 = 760 g of sodium chloride.

 

the trouble is that at 60C only 370g of chloride will dissolve in one litre of water.

 

SO IMO if you electrolyse brine saturated at 60C (NOT brine at 60C that was saturated at 20C) you will need the same amount of chloride crystals again to come close to saturated chlorate.

 

If you get a solution that is saturated with chlorate then you can electrolyse 70% of the chlorate while ignoring the chloride. Then all the electrolyte can be replenished with chloride to start again.

[WSM]

1litre of water will dissolve 1390g of sodium chlorate at 60C

this is 1390/ 106 = 13.1 moles

which comes from 13.1 x 58 = 760 g of sodium chloride.

the trouble is that at 60C only 370g of chloride will dissolve in one litre of water.

SO IMO if you electrolyse brine saturated at 60C (NOT brine at 60C that was saturated at 20C) you will need the same amount of chloride crystals again to come close to saturated chlorate.

If you get a solution that is saturated with chlorate then you can electrolyse 70% of the chlorate while ignoring the chloride. Then all the electrolyte can be replenished with chloride to start again.

 

Hmm, maybe. I believe you and will seek out ways to manipulate things to our favor. Industry does it and I think we can too if we apply ourselves to the task.

 

At this point, I'll have to run my cell for the calculated, requisite time and see. It's all a learning experience for me as I've never attempted sodium chlorate before.

 

It sounds strange, saying that, considering how much effort I'm putting into it and the elaborate setup I've built. We'll see...

 

Thanks for all the input, Arthur.

 

WSM

Edited May 18, 2016 by WSM

[schroedinger]

I can assure you sodium chlorate is a **** to get started. You will need two electrolysis runs, to be able to precipate it out or reduce the volume by more then 50%. At cool temperatures the chloride stas in solution while the chlorate precipates. If you got a stirring device in your cell, you can easly top the chloride up using

I think you got the geocities site downloded, right? There are very goodgraphs for the solubilities, showing all the temperature ranges.

[memo]

the cell is up and running with round 2 , the first round was almost a total failure. managed to get a small amount of crytalized stuff out. still wet and i wont even guess how much. dont even know what chemical it is.

 

bill

[WSM]

I would be very interested in that chart by Swede if you find it!

Loving all the info guys

 

Hi Rkteer,

 

For MMO try eBay item number 201586827117, the seller says they ship to your area.

 

This next seller (laserred) sells used MMO and says he ships worldwide, plus I have and use his material (many of us do). Try eBay item number 351735216804

 

Good luck and tell us how it goes.

 

WSM

[WSM]

I can assure you sodium chlorate is a **** to get started. You will need two electrolysis runs, to be able to precipate it out or reduce the volume by more then 50%. At cool temperatures the chloride stas in solution while the chlorate precipates. If you got a stirring device in your cell, you can easly top the chloride up using

I think you got the geocities site downloded, right? There are very goodgraphs for the solubilities, showing all the temperature ranges.

 

Hi schoedinger,

 

I have no delusions about this being easy. I expect I'll have to take extra measures to make a success of this, but I'm learning and will share what I learn here, Yes I do have a copy (or ten) of the geocities site and refer to them and several others as I study the topic. I also have the means (and will) to apply stirring to the cell when called for.

 

I intend to solve one problem at a time as I encounter them.

 

Thanks for the encouragement.

 

WSM

[WSM]

the cell is up and running with round 2 , the first round was almost a total failure. managed to get a small amount of crytalized stuff out. still wet and i wont even guess how much. dont even know what chemical it is.

bill

 

Hi memo (Guillermo?),

 

Good luck with your second run. Can you show a photo of your setup? If we see it, we can better offer suggestions or constructive criticism (we, here, like to help) and maybe give you some ideas to improve your system.

 

WSM