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making potassium (per) chlorate


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#4921 TomasBrod

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Posted 07 August 2019 - 10:54 AM

if they last three months that's OK to me. 

I do not care as much about they lasting, but what the decomposition products are. If the plastic releases some chemical that attacks or binds to the electrodes, that would be bad.



#4922 WSM

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Posted 15 August 2019 - 02:04 AM

I do not care as much about they lasting, but what the decomposition products are. If the plastic releases some chemical that attacks or binds to the electrodes, that would be bad.


Try it and see. There's no reason to worry before you know whether or not it even works.

I would use the glass jars if they're big enough. The lid doesn't need to seal, but it'll help prevent salt creep if it does. The vent will keep the internal pressure at one atmosphere.

WSM B)

#4923 GrassyKnollShooter

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Posted 28 August 2019 - 06:05 AM

It can be synthesized very easily but you don't appear to have any chemistry background.

 

You're playing with fire my friend.



#4924 WSM

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Posted 01 September 2019 - 08:30 PM

...you don't appear to have any chemistry background.
 
You're playing with fire my friend.


Considering this is the AMATEUR PYROTECHNICS AND CHEMISTRY forum, that's a given.

A chemistry background isn't required, but it certainly helps.

WSM B)

Edited by WSM, 01 September 2019 - 08:34 PM.


#4925 Arthur

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Posted 02 September 2019 - 12:54 PM

Several people on here have lots of higher education and letters after their names and lots of industrial experience in electrochemistry, others have lots of very relevant private study and may make very important contributions to the discussion.



#4926 WSM

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Posted 12 September 2019 - 10:01 PM

I have a 5 liter reaction vessel (round bottom borosilicate glass) which I'm going to make into a little experimental sodium chlorate cell.

I plan to use a fairly thick polymer lid, drilled and tapped for compatible compression fittings, and plumb it for as many useful components as I feel will be useful for the purpose.

The plan, borrowed mostly from a patent Arthur kindly shared, involves running the cell at or near 110 degrees C, which will boil off excess water as the system runs.

This will naturally concentrate the chlorate product, to where crystalline NaClO3 will drop out of solution at room temperature, removing the need and expense of chilling the electrolyte in a refrigerator to harvest the chlorate.

Chlorides can be replaced using purified brine instead of laboriously preparing purified NaCl to use.

I have lots of ideas, developed over the past few years. If the cell is successful, I'll see if I can adapt it to run as a continuous system, to produce a large enough stock of pure sodium chlorate to continue my perchlorate experiments.

WSM B)

Edited by WSM, 13 September 2019 - 04:44 AM.


#4927 WSM

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Posted 16 September 2019 - 09:40 PM

I forgot to mention that the 5 liter reaction flask has a large opening (+-150mm) and there's a groove for an O-ring in the flat flange around the opening.

With a compatible O-ring seal, a flat plate of thick polymer will make an excellent lid and closure for the cell.

We'll see...

WSM B)

#4928 markx

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Posted 19 September 2019 - 02:30 AM

I have a 5 liter reaction vessel (round bottom borosilicate glass) which I'm going to make into a little experimental sodium chlorate cell.

I plan to use a fairly thick polymer lid, drilled and tapped for compatible compression fittings, and plumb it for as many useful components as I feel will be useful for the purpose.

The plan, borrowed mostly from a patent Arthur kindly shared, involves running the cell at or near 110 degrees C, which will boil off excess water as the system runs.

This will naturally concentrate the chlorate product, to where crystalline NaClO3 will drop out of solution at room temperature, removing the need and expense of chilling the electrolyte in a refrigerator to harvest the chlorate.

Chlorides can be replaced using purified brine instead of laboriously preparing purified NaCl to use.

I have lots of ideas, developed over the past few years. If the cell is successful, I'll see if I can adapt it to run as a continuous system, to produce a large enough stock of pure sodium chlorate to continue my perchlorate experiments.

WSM B)

 You do not need to run the cell at boiling hot temperature to drop out the crop of sodium chlorate. Electorlysis/synthesis will spend some water and some will find it's way out as vapours leaving through the off gas conduit.  By replenishing the spent water with concentrated brine you will eventually reach a critical concentration buildup of chlorate in the cell liqour and it will start to cristallise out from the solution. This crop can be regularly removed and you do not need to operate at high temperature for that. The question is how are you going to remove that crop without having to switch off and dissassemble the whole setup. From a technical perspective cooling is about the best method to remove the excess product in a continuous production scheme. The solution can be fed into a different vessel where it cools....drops out the chlorate and then flows back into the reactor vessel. This way the system can keep operating and no dissassembly is required to remove the product. 

 

A boiling hot cell is really hard to control.....your rate of water loss shall not match up with the amount of chlorate produced and you have to replenish the electrolyte constantly with additional water instead of brine. Otherwise you shall quickly start to precipitate chlorides instead of chlorates. Not to mention a boiling system can not be left unsupervised: not good from the viewpoint of a continuous production concept. Also the high temperature limits the choice of materials you can use in the construction of the cell. Simpler and cheaper plastics like PP or PE which perform reasonably well in a moderate temperature cell will soften too much at 110C to provide structural integrity. Deformation, shrinkage and serious leaks are the result. Even 80C will make PP parts creep out of shape when they are under constant mechanical strain in/on an operating cell. My cell has a PP top plate that is grooved and seated with a PTFE gasket to keep the gases and liqour from creeping out.  I operated it a about 80C maximum for a few days during chlorate synthesis and this was enough to warp the PP plate causing serious leaks and salt creep. 



#4929 WSM

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Posted 19 September 2019 - 07:59 AM

You do not need to run the cell at boiling hot temperature to drop out the crop of sodium chlorate. Electorlysis/synthesis will spend some water and some will find it's way out as vapours leaving through the off gas conduit.  By replenishing the spent water with concentrated brine you will eventually reach a critical concentration buildup of chlorate in the cell liqour and it will start to cristallise out from the solution. This crop can be regularly removed and you do not need to operate at high temperature for that. The question is how are you going to remove that crop without having to switch off and dissassemble the whole setup. From a technical perspective cooling is about the best method to remove the excess product in a continuous production scheme. The solution can be fed into a different vessel where it cools....drops out the chlorate and then flows back into the reactor vessel. This way the system can keep operating and no dissassembly is required to remove the product. 
A boiling hot cell is really hard to control.....your rate of water loss shall not match up with the amount of chlorate produced and you have to replenish the electrolyte constantly with additional water instead of brine. Otherwise you shall quickly start to precipitate chlorides instead of chlorates. Not to mention a boiling system can not be left unsupervised: not good from the viewpoint of a continuous production concept. Also the high temperature limits the choice of materials you can use in the construction of the cell. Simpler and cheaper plastics like PP or PE which perform reasonably well in a moderate temperature cell will soften too much at 110C to provide structural integrity. Deformation, shrinkage and serious leaks are the result. Even 80C will make PP parts creep out of shape when they are under constant mechanical strain in/on an operating cell. My cell has a PP top plate that is grooved and seated with a PTFE gasket to keep the gases and liqour from creeping out.  I operated it a about 80C maximum for a few days during chlorate synthesis and this was enough to warp the PP plate causing serious leaks and salt creep.



In a sodium chlorate cell, the product is more soluble than the starting electrolyte. To be perfectly clear, sodium chlorate is much more soluble than the sodium chloride brine.

As the cell runs, the chlorate concentration increases as the chlorides decrease. When the run nears "competition" the depleted electrolyte is saturated with sodium chlorate but so much more water, that to remove the chlorate, one is required to either/or boil the electrolyte/chill it, to concentrate the product enough for it to drop out crystals of NaClO3.

Only a small portion of the sodium chlorate drops out of the electrolyte, leaving the remainder in solution.

I prefer not to boil down the electrolyte in recovering sodium chlorate, because it wastes a lot of energy and may also drop out some sodium chloride if I don't gauge the cutoff correctly between optimal chlorate recovery and the chlorides beginning to precipitate.

The beauty of the method described in the patent Arthur shared, is in it uses the nature of the component chemicals to the best advantage in the recovery of the desired product (sodium chlorate crystals) while keeping the chloride in solution and recharging the cell with brine rather than laboriously produced purified salt.

The whole process described minimizes the energy spent and maximizes the yield produced, so the initial expenditure (more specialized materials and setup of the high temperature cell) is overcome soon after it is run for a few cycles.

Due to the anticipated temperatures and compatibility issues, polymers aren't used in contact with the electrolyte. The choice of cell container in this case is borosilicate glass. Less compatible polymer components are designed to function away from direct contact with the cell liquor, besides PTFE or other such tubing allowed to transfer hot electrolyte to a room-temperature crystallization chamber for crystal recovery. The remaining solution in the recovery container is then mixed with fresh, purified brine and returned to the cell for continued runs.

By utilizing the temperature and solubilities to the greatest advantage, more product can be produced with less energy expenditure and time consumption.

WSM B)

Edited by WSM, 19 September 2019 - 08:14 AM.


#4930 markx

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Posted 19 September 2019 - 02:29 PM

In a sodium chlorate cell, the product is more soluble than the starting electrolyte. To be perfectly clear, sodium chlorate is much more soluble than the sodium chloride brine.

As the cell runs, the chlorate concentration increases as the chlorides decrease. When the run nears "competition" the depleted electrolyte is saturated with sodium chlorate but so much more water, that to remove the chlorate, one is required to either/or boil the electrolyte/chill it, to concentrate the product enough for it to drop out crystals of NaClO3.

Only a small portion of the sodium chlorate drops out of the electrolyte, leaving the remainder in solution.

I prefer not to boil down the electrolyte in recovering sodium chlorate, because it wastes a lot of energy and may also drop out some sodium chloride if I don't gauge the cutoff correctly between optimal chlorate recovery and the chlorides beginning to precipitate.

The beauty of the method described in the patent Arthur shared, is in it uses the nature of the component chemicals to the best advantage in the recovery of the desired product (sodium chlorate crystals) while keeping the chloride in solution and recharging the cell with brine rather than laboriously produced purified salt.

The whole process described minimizes the energy spent and maximizes the yield produced, so the initial expenditure (more specialized materials and setup of the high temperature cell) is overcome soon after it is run for a few cycles.

Due to the anticipated temperatures and compatibility issues, polymers aren't used in contact with the electrolyte. The choice of cell container in this case is borosilicate glass. Less compatible polymer components are designed to function away from direct contact with the cell liquor, besides PTFE or other such tubing allowed to transfer hot electrolyte to a room-temperature crystallization chamber for crystal recovery. The remaining solution in the recovery container is then mixed with fresh, purified brine and returned to the cell for continued runs.

By utilizing the temperature and solubilities to the greatest advantage, more product can be produced with less energy expenditure and time consumption.

WSM B)

Yes of course chlorate is way more soluble in a sodium dominated electrolyte system compared to chloride. I apologize for the fact that I have not read the patent that was mentioned, hence my understanding of the final objective related to this approach is somewhat vague. What I was trying to say is that the electrosynthesis cell, as long as it is run, will keep creeping towards the increase of chlorate concentration indiscriminate of cell temperature or the way it is replenished with chlorides. 

Do I understand correctly that you wish to operate the reactor at an excess of 100C to increase the evaporative removal of water for concentrating the electrolyte faster? Then drop out the maximum cristal crop in a separate cooling vessel and turn it to solid chlorate stock for further perchlorate conversion?



#4931 WSM

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Posted 19 September 2019 - 10:01 PM

Do I understand correctly that you wish to operate the reactor at an excess of 100C to increase the evaporative removal of water for concentrating the electrolyte faster? Then drop out the maximum cristal crop in a separate cooling vessel and turn it to solid chlorate stock for further perchlorate conversion?



Yes, evaporating the water to concentrate the chlorate is a major part of making this system work efficiently.

When the concentrated electrolyte cools from 110 degrees C to room temperature, a portion of the sodium chlorate will drop out of solution as crystals. The remainder of the electrolyte is then recharged with purified brine and returned to the cell to continue making more chlorate.

Making the NaClO3 crystals is crucial to my KClO4 research because I don't have an available source for sodium chlorate, so I'm creating it from materials I can get.

I use the sodium chlorate to form the electrolyte that is processed in a perchlorate cell to sodium perchlorate, using either lead dioxide or platinum anodes with titanium cathodes.

I separate the two processes (chloride to chlorate and chlorate to perchlorate) because it's simpler to keep the quality up of the products if I watch each step carefully. These two systems so different from each other that I treat and run them completely differently.

WSM B)

Edited by WSM, 19 September 2019 - 10:15 PM.


#4932 markx

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Posted 20 September 2019 - 01:07 AM

Yes, evaporating the water to concentrate the chlorate is a major part of making this system work efficiently.

When the concentrated electrolyte cools from 110 degrees C to room temperature, a portion of the sodium chlorate will drop out of solution as crystals. The remainder of the electrolyte is then recharged with purified brine and returned to the cell to continue making more chlorate.

Making the NaClO3 crystals is crucial to my KClO4 research because I don't have an available source for sodium chlorate, so I'm creating it from materials I can get.

I use the sodium chlorate to form the electrolyte that is processed in a perchlorate cell to sodium perchlorate, using either lead dioxide or platinum anodes with titanium cathodes.

I separate the two processes (chloride to chlorate and chlorate to perchlorate) because it's simpler to keep the quality up of the products if I watch each step carefully. These two systems so different from each other that I treat and run them completely differently.

WSM B)

 

May I ask why you insist on bringing the sodium chlorate stock into dry form? Would it not be more convenient to keep it in the form of concentrated solutions prior to workup into perchlorate? 

 

At least that is the way I've done it and it simplifies the process considerably: standard Ti/MMO electrosynthesis to form chlorate from chlorides which is fed into perchlorate cell in the form of concentrated solution as the next step. Your approach seems to go through a lot of effort to temporarily remove the water from a system that will have to be finally handled in the form on solutions anyway. 

 

If you are worried about contaminants and trying to increase the purity of the stock by bringing it into dry form for perchlorate synthesis, then ease your mind: chloride content is not a problem for Pt anode and the rest of impurities seem to always precipitate in the form of a gel like sediment in the last stages of perchlorate conversion. Even visibly contaminated chlorate stock solutions (e.g. contaminated by metallic salts formed from alloying elements in low grade Ti) clear up completely in perchlorate synthesis stage, yielding a very clean solution. 



#4933 WSM

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Posted 20 September 2019 - 08:00 AM

May I ask why you insist on bringing the sodium chlorate stock into dry form? Would it not be more convenient to keep it in the form of concentrated solutions prior to workup into perchlorate?



I have a few reasons for striving to make dry crystalline sodium chlorate.

First, I feel it's easier to calculate the end-of-run in my perchlorate cell if I start with a known concentration in the electrolyte. This way I know the exact quantity of chlorate that's in my starting electrolyte.

Also, my goal in making sodium chlorate is to make a large enough stock of it that I can do a good amount of perchlorate research all at one time, and with the same stockpile, without waiting for several different runs of chlorate to be completed.

Finally, in my opinion; I think it's safer, more controllable and convenient to store NaClO3 as a dry, crystalline substance than as a liquid.

WSM B)

Edited by WSM, 20 September 2019 - 08:09 AM.


#4934 Arthur

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Posted 20 September 2019 - 08:27 AM

Perhaps there is some reason why industrial oxidiser producers use the process that they do, extracting the dried chlorate first. Most times recrystalisation is done to increase the purity and get rid of reaction by-products, and get rid of surplus water.

 

One real issue for amateurs is keeping the waste minimised! A few gallons of chlorate waste will be enough to stop a local waste water plant, or kill vegitation for miles.



#4935 WSM

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Posted 22 September 2019 - 09:28 AM

One real issue for amateurs is keeping the waste minimised! A few gallons of chlorate waste will be enough to stop a local waste water plant, or kill vegitation for miles.



Arthur makes a good point. We need to contain our experiments or we're likely to cause an environmental disaster.

Chlorate, and sodium chlorate in particular, is an indescriminant herbicide. It kills all plants, and "salts" the earth so nothing will grow there for a long time, if ever.

It behooves us to keep our cell in a compatible containment, such as a plastic tub or some other form to prevent a spill from causing harm.

There are other considerations but I'll leave it at that for now.

WSM B)

Edited by WSM, 22 September 2019 - 09:29 AM.


#4936 Arthur

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Posted 22 September 2019 - 10:20 PM

Another point is that we start with hot saturated brine and add brine solution as the reaction progresses so there is increasing cell liquid volume which we wish would not increase so some water losses by evaporation are very helpful in maintaining a reaction liquor of reasonable concentration and saturation.

 

When the second stage cell reaches completion we add saturated KCl to cause the Na perc to ppt out as crystals (rate of addition and temperature govern final crystal size). This means that this cell increases in volume too. This exhausted liquor becomes the NaCl solution that needs saturating to reuse as chlorate cell feedstock. You concentrate it either by adding NaCl and getting an increasing volume of liquor or by removing water.

 

In practice there will be other losses of chemicals and gain of hazards, Simply wiping up spills or drips leaves a oxidiser filled cloth or paper to dry and become easily or spontaneously flammable. 



#4937 WSM

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Posted 01 October 2019 - 04:19 PM

In practice there will be other losses of chemicals and gain of hazards, Simply wiping up spills or drips leaves a oxidiser filled cloth or paper to dry and become easily or spontaneously flammable.



Arthur has made another good point. When you have a hot sodium chlorate solution, it's extremely important not to let it come into contact with organic material.

This is a problem when we use cellulose filter paper to separate crystals from the remaining electrolyte, because the wet filter paper becomes a serious flame hazard when it dries.

This came home for me when I had several such papers to dispose of. I took them out to the barbecue grill and when I "carefully" lit the corner of one, imagine my surprise when it burned VERY quickly, almost like flash paper. Luckily, I was wearing an FR (flame resistant) T-shirt, which did its job and protected my skin. Unfortunately, my FR T-shirt was afterwards peppered with a fair number of very small, black spots (holes) after this experience.

Sodium chlorate coated organic material can be treacherous. Be careful, and dispose of it safely, in SMALL quantities, one at a time and using an ignition device that separates you from the hazard.

WSM B)

Edited by WSM, 04 October 2019 - 12:51 PM.


#4938 pyrojig

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Posted 05 October 2019 - 10:49 PM

To chime in , I believe industry produces dried materials v.s. in solution because of volume and weight for storage.cost and storage space is crucial.
I too have been surprised by how reactivate filter paper and or a clean up rag can be with chlorate in it. Very sobering. I lost arm hair in my experience. Lol, wsm is smart to have proper attire.
I often wonder if the chlorate contaminated soils they used to spray with herbicide eventually went inert. I've almost considered attacking poison oak with that stuff, but fear the lasting results or contamination would not be desirable.




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