Help with potassium chlorate

[Arthur]

I read somewhere that the sodium chloride that industry uses is dissolved in water and filtered to remove suspended solids, then acidified with sulphuric acid to precipitate some metal ions (many sulphates are insoluble) then the liquid is held in a settling tank and the silt left behind and the settled liquor is fed to cells.

 

The electrochemical process for all the chlor compounds is ancient history in chemical terms SO the preparation of the ingredients may be very old fashioned but very functional

[WSM]

I read somewhere that the sodium chloride that industry uses is dissolved in water and filtered to remove suspended solids, then acidified with sulphuric acid to precipitate some metal ions (many sulphates are insoluble) then the liquid is held in a settling tank and the silt left behind and the settled liquor is fed to cells.

The electrochemical process for all the chlor compounds is ancient history in chemical terms SO the preparation of the ingredients may be very old fashioned but very functional

 

 

I'm sure different companies use different methods depending on their individual circumstances and resources. I liked the description of using alkaline sodium salts which were neutralized to only NaCl solution after the purification steps by using dilute HCl solution (sort of a win-win).

 

The use of H₂SO₄ is attractive for the removal of certain heavy metals, if present in the electrolyte components (water, salt or both), but it isn't my first choice. The approach I used, worked very well for my circumstances. Others may have need for different purification methods, depending on what they have to deal with. An analysis of your water is required to understand what needs to be removed, and how much (qualitative and quantitative). City water suppliers usually provide annual reports of municipal water quality, if they're responsible stewards and concerned about public health.

 

Thanks for adding to the discussion and offering an alternative approach.

 

WSM

Edited July 11, 2020 by WSM

[kingkama]

Anyone tried to use dishwasher salt, is sold as super pure. Edited July 12, 2020 by kingkama

[WSM]

Anyone tried to use dishwasher salt, is sold as super pure.

 

 

I'm unfamiliar with that product. I which store and country is it found? Also, how much does it cost per unit of weight?

 

I may have to look into that product. I have a few simple tests to determine the quality/purity of it if I can put my hands on some.

 

WSM

[WSM]

Anyone tried to use dishwasher salt, is sold as super pure.

 

 

Okay, you piqued my curiosity, so I googled it. It's available in the US and worldwide.

 

Strangely enough, it's highly recommended for the brand of dishwasher we have in our home! Even stranger is that I was never made aware of it, even by the dishwasher manufacturer, considering how hard our water is here.

 

I DID try pool salt (for salt water chlorinators) for my sodium chlorate cell, which still tested positive for calcium and magnesium, but much less than regular water softener salt.

 

Considering the cost of dishwasher salt (~$1.50-$5.00 per pound) it hardly compares to generic water softener salt at roughly $0.10-$0.14 per pound, even considering the expense and trouble required to purify it with 1M sodium carbonate solution, distilled water, mixing, filtering and neutralizing with dilute hydrochloric acid.

 

If economy is the deciding factor, purifying it yourself makes perfect sense (plus, after the infrastructure expense, the cost of your oxidizers will dramatically drop, especially if you can source your raw materials in bulk!). If convenience is your goal, try the dishwasher salt (Of course, I haven't tested it yet, but it sounds promising ). Then again, here in the US (currently), buying potassium chlorate and perchlorate, or even ammonium perchlorate is still an option (if convenience is the main objective).

 

Making oxidizers is not convenient; but in some places, It's the only option available. I pray that doesn't ever happen here, but if it does; creative people will still be able to obtain it through their own efforts to learn the craft of chlor-alkali electrochemistry. In this case, knowing how to purify the starting materials, as well as being practiced in it, will be priceless!!!

 

 

WSM

Edited July 12, 2020 by WSM

[redhat3301]

Yeah as someone else said, I would use graphite (carbon rods), as titanium can't be an anode. You can find these in pencils, or even take apart batteries for graphite rods. Keep in mind that these carbon rods have a flux on them that burns out, but I don't know if it would affect the electrolysis process or not. You can remove this flux by passing a large current through the rods or burning them out with a blowtorch.

[WSM]

My first attempt at making KClO3 from KCl solution used graphite.

 

Yuck! What a mess, plus lots of extra effort getting it to run properly, AND the monumental headache of cleaning up your product of all the disintegrated graphite mixed into it.

 

If at all possible, source MMO anode material. Your chlorate setup will be much simpler and WAY cleaner.

 

WSM

Edited July 15, 2020 by WSM

[WSM]

My first attempt at making KClO3 from KCl solution used graphite.

Yuck! What a mess, plus lots of extra effort getting it to run properly, AND the monumental headache of cleaning up your product of all the disintegrated graphite mixed into it.

If at all possible, source MMO anode material. Your chlorate setup will be much simpler and WAY cleaner.

WSM

 

 

If you have no way to get MMO and CP titanium electrodes, and graphite is your only option plus you are willing to go through the extra efforts required to get good clean potassium chlorate, by all means do so. I have an old friend who did and he produced lots of usable potassium chlorate in a continuous running cell he made of PVC drain pipe.

 

He used 1" diameter graphite rods running vertically through 1.5" stainless steel pipes for his electrodes. The cell used three of these electrodes, plumbed in parallel and they were wired in series. His system worked but was labor intensive to maintain and service. He continued this process until I sent him a short video of my simple 3 liter (1 gallon pickle jar) glass cell with MMO and titanium electrodes running. When he saw how clean it was running (after he just completed the monthly cleaning out his cell [the graphite wore down too much to continue use in just a month!]), he was convinced to "modernize" his setup.

 

Working together we modified the electrode setup of his system (sourcing and using 1" OD MMO tubing anodes and CP Titanium tubing cathodes), and it ran cleaner and more efficiently for years before he retired it, due to his advancing age. I made a copy of his cell but never ran it before I moved on to try various other batch systems (remember, his system ran continuously; only stopping to recharge the electrolyte with chlorides, and harvest the chlorate).

 

This is my copy of the heart of his three-cell continuous system.

 

If you search in the blog section, read through the post Homegrown Oxidizers Part Six. Therein are further discussions of continuous systems and a photo of my friend's improved working-version setup (the complex looking one), and a variation I was developing at the time.

 

If you have any questions, I'll try to answer them.

 

WSM

Edited October 12, 2020 by WSM

[Arthur]

MMO is also used by hobby electroplating outfits. I can buy (in the UK) MMO in mesh sheets and platinum on titanium sheet from a hobby electro plating supplier. Look in your country to see whether hobby electro plating (silver/gold/platinum etc) has a supplier.

[SeaMonkey]

Elemental Maker has just put a video up:

 

Self Generating Sanitizer Bottle Testing and Chlorate Cell

 

While the Bottles are rather small and not especially cheap, they are ready made

for immediate use and they work.

 

A Submersible Electrode Assembly for dealing with larger quantities of liquid are

also available and are less expensive.

 

These devices are not high powered so the process of making usable chemical

would be rather slow. Very useful perhaps for small scale experimentation or for

making quantities of Household Bleach easily and inexpensively.

 

Big Clive's video

Edited October 17, 2020 by SeaMonkey

[Arthur]

The product as tested by the two listed youtubers works, It comes cheaply from China. Whether anyone here want's to be limited to a one amp cell who knows. Whether the Chinese electrode pair would survive 24/7/365 use who knows!

 

One of the arts of household bleach is using it weakly enough to kill bio without it destroying lots of other things (dyes, fabrics etc. )

[AnthonyGibson]

As mentioned before, this is done by treating the raw brine with sodium carbonate and sodium hydroxide, which causes the calcium, magnesium and even some iron ions to drop out of solution as flocculant precipitates. This means the contaminating minerals bind together and form heavier particles which eventually drop to the bottom of the container.

 

The resulting, purified brine is then poured (decanted) off the precipitated minerals and collected in separate containers for further treatment before being used for our electro-chemical cell. The precipitated sediment can be further vacuum filtered to remove the last remaining brine, which can be added to the rest of our purified brine and the left over precipitates disposed of. The filtration is done using SLOW grade filter paper (with very small, microscopic pores) because the precipitated minerals are a very fine dust when dry. Due to the extremely small pores of the filter paper, the filtering process usually proceeds slowly.

 

One final step I've used is to test the pH of the purified brine. Typically, after treating with alkali reagents, the pH is high. By treating the purified brine with very small amounts of hydrochloric acid drop-wise, the pH can be lowered to roughly neutral (pH 7.0), or slightly lower, which is ideal for our chlorate cells.

 

WSM, what sort of quantities were you using of the sodium carbonate and sodium hydroxide, say per 1kg of sodium chloride?

 

[WSM]

WSM, what sort of quantities were you using of the sodium carbonate and sodium hydroxide, say per 1kg of sodium chloride?

 

Per 4 gallons of sodium chloride solution (350g NaCl/liter H2O, if I remember correctly), I used about 350 ml of 1M sodium carbonate solution.

 

Sodium carbonate solution in water is more alkaline than expected because some sodium hydroxide is also formed as the carbonate is dissolved.

 

When I added the 1M Na2CO3 solution to the brine, it instantly turned milky white. After sitting for a day, the fine precipitates of calcium carbonate and magnesium hydroxide, had dropped to the bottom of the 5 gallon HDPE bucket I used for a reaction vessel.

 

After decanting the clear brine into another new bucket, I vacuum filtered the rest of the slurry through a fine laboratory filter in a Buckner funnel, to separate the fine solids from the residual brine.

 

The clear, purified brine tested alkaline, so I added HCl dropwise till the brine was neutral to slightly acid, and pure enough to run in my sodium chlorate cell.

 

I fully expect a similar process will work in a potassium chloride brine.

 

WSM

Edited October 22, 2020 by WSM