Help with potassium chlorate

[SeaMonkey]

 

...recrystalization will be good idea.

 

Abc159201,

 

I think so too. My Electrolysis Cell is quite small since I only

deal in small quantities of material. Either a half gallon of

liquid or a full gallon of solution. My cells are made from

polyethylene milk cartons with my electrodes (Carbon and

Steel Nails) inserted into the side of the container about

1/3 of the top to bottom distance from the bottom. I space

my electrodes close together to encourage intimate mixing

of the electrolysis products and operate at a low current

density. The electrodes are positioned horizontally with the

Carbon electrodes above the Steel electrodes. Takes

considerable time but I'm in no hurry and I want to keep Anode

Deterioration to an absolute minimum.

 

I had been using a Linear Regulated Power Supply that I had

built many years ago but have just recently received a Variable

Switching Supply from China which runs very cool. The Constant

Current feature is an added bonus. Slow and easy.

[WSM]

WSM,

I for one would be very much interested in your detailed explanation. I have

a bag of Agricultural Potassium Chloride which I'm certain will need such

purification.

Your "handle" brings to mind Radio Station WSM in Nashville, Tennessee which

was a Saturday Night Tradition at our home in Rural Iowa during the '50s. We'd

tune in to the Grand Old Opry on our home radio to enjoy the program. I kinda

miss those days when radio was king.

 

 

I suggest, first dissolving the agricultural potassium chloride in pure water, and then filtering out any insoluble matter. Repeat as necessary till you have a clear solution of potassium chloride.

 

Once you have a clear filtrate, the next step is to remove unwanted ions from it. I'll preface this step with a "short" history lesson.

 

______

A few years ago, I began to research sodium chlorate production (to be used in making sodium perchlorate which was used for making either potassium or ammonium perchlorate). In researching the process, I learned that industry would first dissolve the salt (sodium chloride) to make a raw brine. The raw brine was then treated with sodium carbonate and sodium hydroxide to cause calcium and magnesium chlorides (the principle contaminants in sodium chloride) to drop out of solution as flocculant precipitates, which were then filtered out.

 

I further discovered that sodium carbonate in water made a strongly alkaline solution, part of it forming sodium hydroxide. The precipitates of calcium and magnesium are calcium carbonate and magnesium hydroxide, respectively (first year collage chemistry). In practice, these precipitates float in the brine, making it look like a mixture of milk and water. I discovered that letting the cloudy solution sit overnight, was sufficient time for the precipitates to drop to the bottom of the container (a 5 gallon [19 liter] bucket in my case).

 

Next, I slowly poured the clear brine off the settled residue, so as not to disturb it (defined as decanting), into another 5 gallon bucket. The remaining mixture of residue and brine was separated by vacuum filtration through a slow grade of laboratory filter paper (required because the residue is composed of very fine particles) in a Buchner funnel. The remaining clear filtrate was then added to the rest of the clear brine, while the residue plus filter paper are thrown away.

 

Lastly, the purified, clear brine was tested and the pH found to be alkaline. Hydrochloric acid (HCl) was added drop-wise till the pH was either neutral or slightly acid. Mumbles (a trained chemist), suggested that soluble iron contaminants were also dropped out using this process.

_____

 

 

I have every reason to believe the same purification steps will work for potassium chloride brine, and have begun work to prove the concept for an article I'm writing to include in the Homegrown Oxidizers series, and later to be added to my blog.

 

I suggest to acquire some potassium carbonate (as pure as can be found), mix it with distilled or deionized water and use it to make a treatment for your now clear potassium chloride brine; following the steps I used to make pure sodium chloride brine. The pure potassium chloride solution can then either be electrolyzed to make pure potassium chlorate or used to react with sodium perchlorate to make potassium perchlorate by metathesis.

 

I truly believe that since we're going to the trouble of making our own oxidizers, why not make them at least as good as commercial oxidizer salts; or even better?!!

 

WSM

 

Edit: if you need further clarification on any of these steps or suggestions, feel free to ask.

Edited March 25, 2020 by WSM

[PHI]

 

 

That sounds acceptable (you DO mean potassium chloride, right?). I've found that once you dissolve the salt, if you filter the resulting solution, visible contaminants are often removed. Just use the clear solution.

 

If further purification is needed, adding some potassium carbonate solution (usually a small percentage by volume), will tend to drop unseen calcium, magnesium and iron contaminants, out of solution as flocculant precipitates which can be filtered out.

 

There are several other details to this purification process which will ensure success, plus yield very pure results and better-than-commercial grade oxidizers. I can explain in detail if needed...

 

WSM

Yes, potassium chloride salt, I confuse some terms with the language.

One question about dissolve the salt,

I must use distilled water, or common water is OK?

And, for dissolve the salt I need to heat the water, true? I need to heat until the water boil?

 

Thanks.

[PHI]

 

 

No,Yes, potassium chloride salt, I confuse some terms with the language.

One question about dissolve the salt,

I must use distilled water, or common water is OK?

And, for dissolve the salt I need to heat the water, true? I need to heat until the water boil?

 

Thanks. it sounds like you've got it.

 

Running the power supply at 80% of its capacity isn't required, but it is the best electrical practice for reliability of operation.

 

I've often said it's better to get a power supply and match your electrodes to it, rather than to buy electrodes and try to match a power supply to them. Of course, I do have the ability to make custom fitted electrodes, so that drives my opinion.

 

WSM

Yeah, thank you so much WSM.

 

And thank you to all for help me, this forum is incredible.

 

I think the anode, because have a layer of metal oxide cannot be cutted, but the cathode, only titanium, you can cut it without problem, rigth?

[PHI]

Another thing regarding anodes and cathodes. You don't want a 1:1 ratio of anode to cathode surface area. In any electrochemistry reaction you want a higher current density (smaller surface area) at the electrode where the desired reaction is taking place. In a reduction reaction, such as chrome plating you would want a higher current density at the cathode; which is where the chromium ions in solution are being reduced to metallic chromium. In a perchlorate cell you want a higher current density at the anode; which is where the chloride ions are being oxidized to perchlorate. I would run somewhere between a 1.5-2:1 ratio of cathode surface area to anode surface area

If I understand correctly, I need an anode smaller than a cathode.

In my case, how can I do it, because I have an anode and a cathode of the same size, I don't think that the anode can be cut and the cathode would not know how to join it to another to make the piece bigger.

 

Is this to improve efficiency? Or is it something essential?

 

Thanks friend

[PHI]

 

You don't need 5V fixed voltage. Theoretically, you only need 3.xV to run the chlorate cell. But due to cell design, the internal resistance will vary. Increasing the voltage will drive more current through the electrolyte. And like MadMat has said, you can change the anode to cathode ratio. Personally, I run my cell at 3:1 ratio in order to protect my anode. At this ratio, the cathode is definitely overloaded. No matter how high the voltage is, the current will not rise thus capping the current density of the anode. The downside is higher wear rate of the cathode.

But....meh, who cares

I understand that I need an anode with smallest surface than cathode. And anode of 3^2 inches vs a 9^2 inches cathode is a correct configuration, rigth.

 

Can I use two catodes instead one bigger.

For example:

A and C are cathodes of 4^2 inch and B is anode of 3^2 inch.

 

A B C

- + -

- + -

- + -

- -

 

Is this Okey?

[WSM]

Yes, potassium chloride salt, I confuse some terms with the language.

One question about dissolve the salt,

I must use distilled water, or common water is OK?

And, for dissolve the salt I need to heat the water, true? I need to heat until the water boil?

Thanks.

 

 

Tap water, or common water as you call it, often has dissolved solids in it (which add contaminants to your cell). These are in the form of ions, detectable using a TDS (total dissolved solids) meter.

 

Distilled or deionized water have no dissolved solids, and are helpful in not adding any unwanted ions to your cell. If the starting brine is pure, using pure water will help keep the process purer.

 

Dissolving the salt can be done by simply letting the salt and water sit for long enough at room temperature. This can take a long time. Heating and/or stirring the salt and water speeds the process, but doesn't require "boiling" the mixture. Boiling the mixture risks making a "super-saturated" solution, which will suddenly drop out a mass of salt crystals when the temperature drops and ANY trigger causes the crystals to form (a process useful in other cases but not for making brine for electrolysis).

 

I have made brine by using a pump to move the water through the course salt crystals. This method if fairly clean and doesn't require heating. A lot of brine can be made this way, and even stored in the mixing container when the weather is warm.

 

WSM

[WSM]

Yeah, thank you so much WSM.

And thank you to all for help me, this forum is incredible.

I think the anode, because have a layer of metal oxide cannot be cutted, but the cathode, only titanium, you can cut it without problem, rigth?

 

 

I have cut the MMO mesh anode material using a hacksaw. I use a fine tooth blade in the saw, plus wrap the MMO mesh with paper towels or cloth to prevent physical damage to the coating and while holding the mesh in a vice during the cutting step.

 

The exposed titanium edges of the electrode material don't hurt anything during electrolysis because of the nature of titanium being a "valve metal". I prefer to spot weld (resistance weld) the titanium leads to the electrodes. The anode material doesn't need to be removed before spot welding, but do spot weld outdoors or in an area with good ventilation (avoid breathing the fumes).

 

WSM

[WSM]

If I understand correctly, I need an anode smaller than a cathode.

In my case, how can I do it, because I have an anode and a cathode of the same size, I don't think that the anode can be cut and the cathode would not know how to join it to another to make the piece bigger.

Is this to improve efficiency? Or is it something essential?

Thanks friend

 

 

The use of electrodes in a small cell setup aren't as critical as when the system is scaled up for larger systems. The small scale of your setup is very much more forgiving than a large setup is, so I don't recommend changing the size ratio of your electrodes.

 

The biggest difference will be seen if you add a second cathode plate, surrounding your anode with two cathodes. This optimizes the use of the anode and nearly doubles the production of your cell (and also doubled the current demand of your setup).

 

Something to consider if you want to modify your cell.

 

WSM

[WSM]

I understand that I need an anode with smallest surface than cathode. And anode of 3^2 inches vs a 9^2 inches cathode is a correct configuration, rigth.

Can I use two catodes instead one bigger.

For example:

A and C are cathodes of 4^2 inch and B is anode of 3^2 inch.

A B C

- + -

- + -

- + -

- -

Is this Okey?

 

 

If you review my blogs, there are examples of single pairs of electrodes and also anodes surrounded by two cathodes. Most of these experimental cells use anode and cathode plates of the same size. In the smaller (non-commercial) sized cells like most of us amateurs build, the ratio of anode to cathode size is MUCH more forgiving than in the large cell setups.

 

An electrode setup using larger surface areas in a smaller space can be made by "sandwiching" multiple anodes between cathode plates. I've made but not yet used such electrode arrangements. If and when I do try them, I'll report it in the (per)chlorate thread.

 

Without pH control, our cells run at about 50% efficiency maximum anyway, so why worry about minor efficiency differences in the electrode area ratio?

 

Bigger differences are seen in large cell setups with the little details that others here are stressing. For example, Commercial cell setups typically use 3.6 Vdc, where we run anywhere from 2.5 to 5 Vdc and our systems work. Industrial cells would be highly inefficient running the way our small cells operate, but we're not competing in the marketplace like they are.

 

Also, if you have a larger power supply, don't worry about too much about excess current. Our cells will take what Amperage they need, and the rest is left unused. Basically, you can't "force-feed" more current into the cell than it can use.

 

Voltage is like electrical pressure, where only enough to drive the circuit is required. Amperage is like the "volume" of electrons flowing. The larger the surface area of our anodes, the more current will be demanded by them, but no more.

 

We're happy to make oxidizers for our own use, regardless of the cost, so don't worry so much about the minor details until you're ready to scale up.

 

WSM

Edited March 25, 2020 by WSM

[PHI]

 

 

If you review my blogs, there are examples of single pairs of electrodes and also anodes surrounded by two cathodes. Most of these experimental cells use anode and cathode plates of the same size. In the smaller (non-commercial) sized cells like most of us amateurs build, the ratio of anode to cathode size is MUCH more forgiving than in the large cell setups.

 

An electrode setup using larger surface areas in a smaller space can be made by "sandwiching" multiple anodes between cathode plates. I've made but not yet used such electrode arrangements. If and when I do try them, I'll report it in the (per)chlorate thread.

 

Without pH control, our cells run at about 50% efficiency maximum anyway, so why worry about minor efficiency differences in the electrode area ratio?

 

Bigger differences are seen in large cell setups with the little details that others here are stressing. For example, Commercial cell setups typically use 3.6 Vdc, where we run anywhere from 2.5 to 5 Vdc and our systems work. Industrial cells would be highly inefficient running the way our small cells operate, but we're not competing in the marketplace like they are.

 

Also, if you have a larger power supply, don't worry about too much about excess current. Our cells will take what Amperage they need, and the rest is left unused. Basically, you can't "force-feed" more current into the cell than it can use.

 

Voltage is like electrical pressure, where only enough to drive the circuit is required. Amperage is like the "volume" of electrons flowing. The larger the surface area of our anodes, the more current will be demanded by them, but no more.

 

We're happy to make oxidizers for our own use, regardless of the cost, so don't worry so much about the minor details until you're ready to scale up.

 

WSM

Hi WSM, thank you a lot for your help.for the moment Im going to use only one anode and one cathode, because my power supply is small.

In the future maybe I take a 5v 60A powersupply.

 

For now if I can obtain 5g of p chlorate will be a great win.

Im going to post the result of this experiment in this forum

 

Thanks friend

[WSM]

Hi WSM, thank you a lot for your help.for the moment Im going to use only one anode and one cathode, because my power supply is small.

In the future maybe I take a 5v 60A powersupply.

For now if I can obtain 5g of p chlorate will be a great win.

Im going to post the result of this experiment in this forum

Thanks friend

 

 

You're welcome, and good luck.

 

WSM

[SeaMonkey]

WSM,

 

I appreciate your more detailed procedural explanation for purifying

Agricultural Potassium Chloride. There is a local Soap-Making shop

which sells Potassium Carbonate and I do have some Potassium

Hydroxide.

 

As a teen I used to extract Potassium Carbonate from wood ashes

taken from my Grandma's old kitchen wood-fired cook stove.

 

I'd then mix with it some home-made Calcium Oxide (QuickLime) to

form a small quantity of Potash Lye for making soft soap from lard.

 

My Grandma was quite the soap maker. All the soaps in her home

back then were soaps that she made herself. I miss those days out

on her farm long ago.

 

Thanks again. I'm eager to give it a go.

 

Arthur,

 

Thanks to you I've finally acquired a Mesh MMO Anode from the

supplier who you linked to on page 1 of this topic. I figured it

was about time I transitioned from Graphite Anodes to the

much more durable MMO and I really appreciate your link

to a reliable source.

Edited March 27, 2020 by SeaMonkey

[Mumbles]

WSM said that boiling the solution while creating the KCl solution isn't required. That is true, but I thought I might add some additional comments about that. Boiling may be advantageous while doing the carbonate/hydroxide treatment. As WSM stated, any precipitated calcium or magnesium or other ions tend to be very fine and stay suspended. Boiling this milky mixture often has the added benefit of causing the particles to aggregate and fall out of suspension much faster, and less easy to disturb. The downside is of course more energy expenditure and some additional time. That may be a non-factor if you use the hot solution to both speed up solvation and do the purification treatment. As WSM mentioned, this has the potential to make super-saturated solutions. You'd want to ensure you're working in concentration that will remain soluble at ambient temperature.

 

If you have any around from making Fencepost Prime, mixing in some diatomaceous earth/celite can be a very efficient filter aid to help keep fine particles from passing through filters. This can be wet and added to the surface of the filter, or mixed into the solution. Mixing it into the solution is probably faster, easier and actually more efficient, but you may need to recollect the first liter or two of filtrate and add it back to the main solution. Sometimes it can take a minute for an efficient filter bed to form.

[WSM]

WSM,

I appreciate your more detailed procedural explanation for purifying

Agricultural Potassium Chloride. There is a local Soap-Making shop

which sells Potassium Carbonate and I do have some Potassium

Hydroxide.

As a teen I used to extract Potassium Carbonate from wood ashes

taken from my Grandma's old kitchen wood-fired cook stove.

I'd then mix with it some home-made Calcium Oxide (QuickLime) to

form a small quantity of Potash Lye for making soft soap from lard.

My Grandma was quite the soap maker. All the soaps in her home

back then were soaps that she made herself. I miss those days out

on her farm long ago.

Thanks again. I'm eager to give it a go.

Arthur,

Thanks to you I've finally acquired a Mesh MMO Anode from the

supplier who you linked to on page 1 of this topic. I figured it

was about time I transitioned from Graphite Anodes to the

much more durable MMO and I really appreciate your link

to a reliable source.

 

 

I also have both potassium carbonate and hydroxide available (I'd like a link to your source though, we never have too many sources of supply).

 

I discovered through research that when a solution of potassium carbonate is made, part of the carbonate converts to hydroxide in the solution, making two things happen: 1) we have a ready mixed solution to use for purifying the potassium chloride brine of unwanted ions, and 2) the alkalinity of the solution is much higher than it would be as a carbonate solution alone.

 

The process of soap making is fascinating also, and I plan to do some at a future time.

 

The difference between graphite and MMO anodes is dramatic. Chlorate production using MMO is a vastly cleaner process and can proceed at much higher temperatures (which is also more efficient) than with graphite. BUT, if graphite is all you can get, it still works if you mind the required steps to clean up your electrolyte before replenishing with chlorides and doing subsequent runs. MMO is much simpler.

 

WSM

Edited April 2, 2020 by WSM

[WSM]

WSM said that boiling the solution while creating the KCl solution isn't required. That is true, but I thought I might add some additional comments about that. Boiling may be advantageous while doing the carbonate/hydroxide treatment. As WSM stated, any precipitated calcium or magnesium or other ions tend to be very fine and stay suspended. Boiling this milky mixture often has the added benefit of causing the particles to aggregate and fall out of suspension much faster, and less easy to disturb. The downside is of course more energy expenditure and some additional time. That may be a non-factor if you use the hot solution to both speed up solvation and do the purification treatment. As WSM mentioned, this has the potential to make super-saturated solutions. You'd want to ensure you're working in concentration that will remain soluble at ambient temperature.

If you have any around from making Fencepost Prime, mixing in some diatomaceous earth/celite can be a very efficient filter aid to help keep fine particles from passing through filters. This can be wet and added to the surface of the filter, or mixed into the solution. Mixing it into the solution is probably faster, easier and actually more efficient, but you may need to recollect the first liter or two of filtrate and add it back to the main solution. Sometimes it can take a minute for an efficient filter bed to form.

 

 

I hadn't thought of the benefit of boiling during the purification steps, but considering the scale I was working in (multiple 5 gallon buckets-full) it wouldn't have been practical or economical. On a small scale, yes.

 

I also like the suggestion of adding diatomaceous earth to the filtering process. I can see where this would make up for marginally useful filter paper if good quality lab-grade filter paper isn't available or too expensive.

 

Thanks for adding to the discussion, and for the useful tips, Mumbles!

 

WSM

[Arthur]

Wherever you live the tap water will have dissolved solids. If you have an analysis of the water, you could work out a plan to precipitate materials that will interfere with the electrolysis, but for small quantities it's probably disproportionately time and money consuming. Purportedly sulphuric acid was added to ppt as sulphates lots of odd heavy metals such as lead as insoluble sulphates, but this required settling and floculating an active electrolyte for periods approaching a week!!

[WSM]

If only small amounts of purified water are needed, an improvised solar still can be set up using a plastic wash tub and thin plastic sheet. A google search will show diagrams of the concept.

 

A fabricated distillation setup will also work, leaving the contaminants in the boiler section.

 

WSM

[Arthur]

Purifying the water is simple by modern standards, gallons of ro/deionised (etc) water are available in stores. If you must, then distillation in glassware works, but is energy expensive.

Getting pure salt is harder as most domestic salt is iodised, and contains anti-caking additives. All of the additives will be food safe chemicals but some may make our chosen reactions have impurities. First, read the label on the packet! "Table salt" may be a better, purer, but more expensive starting material than sacks of salt for ice clearance on roads.

 

The challenges are more that in long term water reuse in a chlorate cell normally insignificant sulphates, carbonates, silicates etc. will build up steadily from both salt and water inputs.

[WSM]

Purifying the water is simple by modern standards, gallons of ro/deionised (etc) water are available in stores. If you must, then distillation in glassware works, but is energy expensive.

Getting pure salt is harder as most domestic salt is iodised, and contains anti-caking additives. All of the additives will be food safe chemicals but some may make our chosen reactions have impurities. First, read the label on the packet! "Table salt" may be a better, purer, but more expensive starting material than sacks of salt for ice clearance on roads.

The challenges are more that in long term water reuse in a chlorate cell normally insignificant sulphates, carbonates, silicates etc. will build up steadily from both salt and water inputs.

 

 

I've found that purifying water can be done for about $100 US dollars with materials found and available on eBay. This involves an RO (reverse osmosis) system coupled with a DI (de-ionizing) filter. I plan to set up such a system from materials I've accumulated in the past couple years. When I do, I'll post descriptions and photos for others to see and duplicate if they wish to.

 

As expensive as that may sound, it's less costly than making or buying distilled water. At least in the long run, DI water is cheaper.

 

I avoid table salt, but use water softener salt (either sodium chloride or potassium chloride) for making brine for electrolysis or metathesis. Table salt has too many additives that prevent an easy purification process. Speaking of purifying brine, it IS time consuming, but it's easier and more economical to purify the starting materials, rather than the final products.

 

As for the sodium chloride water softener salt, the least expensive version seems to work the best (the ones without system protecting additives). I also tried using sodium chloride made for salt water pools, but it was contaminated with calcium and magnesium, too. Since I have to purify the brine anyway, I may as well not waste money on the more expensive pool grade.

 

I can't speak as to the road de-icing salt. It seems to be mixtures of much more inferior grades of salts.

 

Perhaps untreated food grade, rock salt may be more pure. I need to test some and see. Food grade is probably more expensive, though.

 

WSM

Edited April 5, 2020 by WSM

[SeaMonkey]

A video which demonstrates very simply the process of

Solar Water Distillation. Modifications to the concept in

order to increase both the efficiency and the quantity

of water purified each day should come to mind readily.

[WSM]

A video which demonstrates very simply the process of

Solar Water Distillation. Modifications to the concept in

order to increase both the efficiency and the quantity

of water purified each day should come to mind readily.

 

 

Not bad, but very small scale.

 

Google has some ideas, but I like the descriptions and variety of suggestions on Wikipedia, under the heading of "solar still - water"). Have a look and see what you think...

 

WSM

Edited April 12, 2020 by WSM

[WSM]

The simplest method to make distilled water I've seen, is to modify a teapot and add a condenser to the spout (where the water vapor exits) and collect the distilled water after the condenser has returned the vapor to liquid water. If done with easily removed silicone tubing connectors, the whole setup could be done while heating water for other cooking purposes (or just for making pure distilled water, your choice).

 

Also, if easily removed, no permanent modification of the teapot is required, only assembly and disassembly of the distillation setup.

 

A lot can be learned from such a simple exercise.

 

WSM

Edited April 26, 2020 by WSM

[WSM]

I've found that purifying water can be done for about $100 US dollars with materials found and available on eBay. This involves an RO (reverse osmosis) system coupled with a DI (de-ionizing) filter. I plan to set up such a system from materials I've accumulated in the past couple years. When I do, I'll post descriptions and photos for others to see and duplicate if they wish to.

As expensive as that may sound, it's less costly than making or buying distilled water. At least in the long run, DI water is cheaper.

I avoid table salt, but use water softener salt (either sodium chloride or potassium chloride) for making brine for electrolysis or metathesis. Table salt has too many additives that prevent an easy purification process. Speaking of purifying brine, it IS time consuming, but it's easier and more economical to purify the starting materials, rather than the final products.

As for the sodium chloride water softener salt, the least expensive version seems to work the best (the ones without system protecting additives). I also tried using sodium chloride made for salt water pools, but it was contaminated with calcium and magnesium, too. Since I have to purify the brine anyway, I may as well not waste money on the more expensive pool grade.

I can't speak as to the road de-icing salt. It seems to be mixtures of much more inferior grades of salts.

Perhaps untreated food grade, rock salt may be more pure. I need to test some and see. Food grade is probably more expensive, though.

WSM

 

 

The food grade salt industry doesn't offer pure NaCl salt because it's unnecessary. Trace amounts of certain metals are beneficial for human health, so why bother? In fact calcium and magnesium (two of the main contaminants of raw commercial salt, including sea salt) are essential for proper human immune response and other critical bodily functions.

 

Also, "iodized salt" has not only iodine compounds, but other additives (such as silicates and/or sodium ferrocyanide decahydrate) to keep it free flowing, which are unneeded and unwanted in our chemical processes.

 

So, what does the commercial chlor-alkali industry do? They remove them by purifying the brine they make (in large tanks or ponds) from the bulk, raw salt purchased from industrial suppliers.

 

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.

 

I am trying to show enough details of the process, so others can repeat what I've done, but I may have missed something in the effort. If anyone has questions, feel free to ask in this forum so all may benefit from the discussion.

 

WSM

Edited June 9, 2020 by WSM

[WSM]

The food grade salt industry doesn't offer pure NaCl salt because it's unnecessary. Trace amounts of certain metals are beneficial for human health, so why bother? In fact calcium and magnesium (two of the main contaminants of raw commercial salt, including sea salt) are essential for proper human immune response and other critical bodily functions.

Also, "iodized salt" has not only iodine compounds, but other additives (such as silicates and/or sodium ferrocyanide decahydrate) to keep it free flowing, which are unneeded and unwanted in our chemical processes.

So, what does the commercial chlor-alkali industry do? They remove them by purifying the brine they make (in large tanks or ponds) from the bulk, raw salt purchased from industrial suppliers.

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.

I am trying to show enough details of the process, so others can repeat what I've done, but I may have missed something in the effort. If anyone has questions, feel free to ask in this forum so all may benefit from the discussion.

WSM

 

 

After re-reading this post, I see the question is unclear.

 

The question should be, "What does industry do to purify bulk, raw salt?" Their source is NOTHING like regular table salt, with all of it's additives. It's just either dried sea salt or mined mineral salt; fundamentally sodium chloride with whatever other natural minerals that are associated with it (usually calcium and magnesium).

 

This should clarify what I intended to say.

 

WSM