making potassium (per) chlorate

[Arthur]

I think you will need to fund some clothes shopping for her!

[WSM]

I think you will need to fund some clothes shopping for her!

Double ouch!

 

I think you're right (unfortunately ).

 

WSM

Edited September 18, 2015 by WSM

[WSM]

Thinking about the next logical step in my electrochemistry research (making sodium chlorate for perchlorate cell feed stock), I shopped the local hardware stores for inexpensive sources of "pure" (no additives) salt (NaCl) to use for my sodium chlorate cell electrolyte. My search was rewarded with a "no frills" version of water softener salt for less than twenty cents per kilogram.

 

I plan to set up a larger cell, maybe 20 liters and try it out. Having never attempted to make sodium chlorate, this will be "uncharted waters" for me. Arthur has sent several helpful articles to me for reference, and the one he's most anxious for me to try is a commercial system involving high temperatures with resulting higher yields.

 

It sounds promising, but I may start out more modestly. I may have to work up to that one rather than go all in at the start, We'll see...

 

I've been reviewing Swede's Blogs and see that a couple things he tried, the two cell version with an electrode chamber and the reaction/crystallization chamber; that failed for a potassium chlorate system, would work perfectly for a sodium chlorate system. I suspect his inspiration for the attempts was from descriptions of commercial processes involving sodium rather than potassium salts.

 

The key is to let the various solubilities work for you instead of against you.

 

WSM

[Arthur]

What bugs me about electrolysing KCl is that there is waste liquor that is hard to recycle, In small quantities this can go down the municipal drain BUT some bits are herbicidal so spillage on land would be noticed.

[WSM]

What bugs me about electrolysing KCl is that there is waste liquor that is hard to recycle, In small quantities this can go down the municipal drain BUT some bits are herbicidal so spillage on land would be noticed.

 

I'm sorry, I don't understand this comment at all.

 

Maybe there's a point I'm missing, but most of us filter out the KClO₃, recharge the electrolyte with more KCl and run the cell again. If fact, Swede's Blogs are replete with his experiences of making potassium chlorate and reusing the replenished electrolyte after harvesting the previous batches.

 

Let us know if we're misunderstanding your meaning. Thanks.

 

WSM

[WSM]

I'm sorry, I don't understand this comment at all.

Maybe there's a point I'm missing, but most of us filter out the KClO₃, recharge the electrolyte with more KCl and run the cell again. If fact, Swede's Blogs are replete with his experiences of making potassium chlorate and reusing the replenished electrolyte after harvesting the previous batches.

Let us know if we're misunderstanding your meaning. Thanks.

WSM

 

I may have figured out the misunderstanding Arthur and I appear to be having having. I'm presuming we're all using potassium chloride water softening salt (or something similar) as a starting point. If KCl isn't available then my assumption is false, and all sorts of alternative sources of potassium chloride may be tried with varying degrees of success (or different failure modes, as the case may be).

 

For example; some use salt substitute, which is a mixture of potassium chloride and sodium chloride, and may require special handling to get positive results. Agricultural KCl (AKA: muriate of potash) usually has other materials (contaminants) included which should be removed before use in a chlorate cell.

 

It's true that chlorates are aggressive herbicides (in fact, I describe sodium chlorate as "an indiscriminate herbicide" which just kills all plant life), and careful handling is called for when using them outdoors. One should never dump depleted cell liquor on the ground or down the drain. If unsure how to handle it, ask here (someone here should have the answer).

 

For those of us who have access to potassium chloride water softening salt, the typical method used to handle depleted mother liquor is to recharge it with fresh potassium chloride crystals and use it in the subsequent runs of our potassium chlorate cells. The subsequent runs will produce much more chlorate, plus sooner, due to the abundant precursors and left-over chlorates from previous runs remaining in the depleted liquor.

 

Best regards, Arthur.

 

WSM

[MrB]

One should never dump depleted cell liquor on the ground or down the drain. If unsure how to handle it, ask here (someone here should have the answer).

 

I've actually been thinking about this one for a while. The optimal system just recharges, and keeps going, but in the reality, our chemicals wont be perfect, and hence we will get buildups, contamination, and, "other issues" (dissolving anodes?) that will make us want to get rid of the fluids at some point. And what IS really the proper way to treat this?

 

Keeping in mind that (per)chlorates is now will be illegal to own in a fairly short time over here, so you cant just take it to a hazardous waste facility and tell them what you got, and hope they take it of your hands. (As civilians we got the right to turn our hazardous waste in for free, but we have to identify it, or they wont be able to dispose of it safely... If at all. It's not like they have a continual supply of out kind of fluids to dispose of, so they may very well be just as crestfallen as we are, with the available options.)

Dropping the fluids of as a "unknown" behind the personnels back is likely to make it end up misstreated, sent to the wrong process, and so on. It's not an option.

 

Knowing a bit about the waste water purification plant we got here in my town, it's a bio/chemical facility, using bacteria, and algea to purify the water as best they can, after which a calcium / carbonation process is used to create a sludge that separates out, and the fresh water returns to the ocean. Ditching (per)chlorates in to this system is likely to wipe out all traces of the algea from the system in a hurry, if the concentration is high enough. Since you cant tell the whole town when to flush their toilets just so you can toss out your fluids, the water treatment plant is simply a bad idea.

 

That all said, what really IS a viable option? Im not exactly in a place where i even need to start a cell yet, but sooner or later i will have to, and the question is going to be quite relevant at that point...

 

@WSM, thank you for your ongoing efforts.

B!

[Arthur]

If you clean up a run of KCl to perc (via chlorate) then you have to remove K chlorate by metabisulphite. This must leave a sulphur compound (sulphate?) in the liquor as solute or solid. If you recycle a liquor with ever increasing sulphate(?) content then soon the electrolyte will need changing.

 

If you run NaCl cell then on adding KCl to a tank of NaClO₄ will first precipitat out KPerc, then with further KCl the KChlorate will drop out.

 

What I think we want is to add just enough KCl to ppt out the perc salt as KPerc BUT leave the chlorate as the Na salt to go back round the electrolysis cell.

 

Odd things in the cell -sulphate chromate etc, all begin to accumulate ans interfere with the desired reaction -one text I read suggested adding dichromate to protect stainless steel electrodes then adding barium chloride to precipitate the chrome salts -so there would be a Barium chromate/dichromate sludge to dispose -which isn't garden fertiliser!

 

If we make by electrolysis 1 mole of perchlorate ion then 1 mole of KCL should exactly precipitate it all out and NO chlorate. Better we make 1 mole perc and add 0.995moles of KCl so that precipitation is almost complete but NO chlorate is precipitated. ALL the potassium is precipitated out so only replenishment with a little NaCl may be necessary.

If we put the optimum number of amphours into the perc cell to make n moles of perc then we should be able to take n moles of perc out each time, even if we have some perc always in there an always being recycled.

[WSM]

The process I used to make samples of KClO₄ from my homegrown NaClO₄ involved;

1. destroying residual NaClO₃ with SO₂ from sodium metabisulfite (Na₂S₂O₅) solution
2. adding KCl solution to immediately drop out KClO₄
3. vacuum filtering the salt using slow lab grade filter paper
4. rinsing the salt with cold distilled water while the vacuum is still running
5. drying the salt samples in an evaporation dish over boiling water
6. storing the dried samples in clean bottles for later testing

The filtrate (left over liquid separated from the newly formed potassium perchlorate samples) is indeed full of sulfate (SO₄^-2) as well as Na⁺ and Cl^- ions in the solution. The sulfates can be conveniently removed by adding a solution of calcium chloride (Damp-Rid here in the US). The sulfates drop out of solution as calcium sulfate and can be filtered out. Any calcium salts left in the solution can be removed with a slight excess of sodium sulfate solution.

 

It's desirable to remove all calcium salts to prevent the formation of hazardous calcium chlorate [Ca(ClO₃)₂] in subsequent runs with recycled electrolyte.

 

If done carefully and completely, the replenished electrolyte is primarily NaCl solution plus chlorate precursors (hypochlorite, hypochlorous and chlorate ions), with few if any contaminants.

 

WSM

Edited September 21, 2015 by WSM

[WSM]

@WSM, thank you for your ongoing efforts.

B!

 

You're welcome, though it's the sharing of my efforts that's the best contribution to the cause. Several folks have made similar efforts but I'm trying to add to the body of knowledge here by documenting what I learn in the process of creating chlorates and perchlorates for pyrotechnic display and competition.

 

I appreciate your support of my efforts. Thank you, MrB.

 

WSM

Edited September 20, 2015 by WSM

[WSM]

Well, I took the plunge.

I've been salivating over some larger power supplies on eBay for some time now. The one that caught my eye is a Sorensen 0-7.5 Vdc, 0-140 A, rack mount unit. The typical asking price for these things is $450-$600 (ouch!).

One company (a salvage seller), had nine of them and said about $500+ shipping or best offer, so I figured, "What the heck?" and offered $150 (plus shipping at $38.28, or 188.28 total). This morning I woke up to a message saying that I got it (they accepted my offer)! Uh oh, they called my bluff ; now what do I do?!!

Being an upstanding fellow, I commit to buy it and pull out the magic plastic... Done (now I have six months to pay for it before my wife figures out my folly).

When it arrives I'll put it through it's paces and see if it's the excellent score I hope it is. I'll let you know...

WSM

 

The power supply arrived in great shape and I immediately tried it out. I learned a lot but couldn't get an output . I figured I must be missing something so I looked for and downloaded an instruction manual for it and begin a thorough search through it.

 

Several points were made in the manual, so I investigated much more carefully. Unfortunately, my final determination was that the supply was defective, so I contacted the seller and asked them if they could help me or exchange it (they still have eight more of these units). They asked a few searching questions about my problem solving techniques, and satisfied that I made a good faith effort to make it work, they sent a return authorization and return shipping label.

 

I've sent it back and I'm waiting for a replacement to arrive. They mentioned sending either a replacement or a refund. I really want a replacement rather than a refund!!! During my study of the instruction manual, I became much more impressed with the power supply and all the features it has. If I get a good, functioning unit, it'll be the number one power supply I use for all my electrochemical experiments and research.

 

WSM

Edited October 2, 2015 by WSM

[Ubehage]

 

The power supply arrived in great shape and I immediately tried it out. I learned a lot but couldn't get an output . I figured I must be missing something so I look for and downloaded an instruction manual for it and begin a thorough search through it.

 

Several points were made in the manual, so I investigated much more carefully. Unfortunately, my final determination was that the system was defective, so I contacted the seller and asked them if they could help me or exchange it (they still have eight more of these units). They asked a few searching questions about my techniques, and satisfied that I made a good faith effort to make it work, they sent a return authorization and return shipping label.

 

I've sent it back and I'm waiting for a replacement to arrive. They mentioned sending either a replacement or a refund. During my study of the instruction manual, I became much more impressed with the power supply and all the features it has. I really want a replacement rather than a refund!!! If I get a good, functioning unit, it'll be my number one power supply for all my electrochemical experiments and research.

 

WSM

Sorensen usually is of VERY high quality, and made for people who know what they're paying for.

Have fun

[WSM]

The power supply arrived in great shape and I immediately tried it out. I learned a lot but couldn't get an output . I figured I must be missing something so I looked for and downloaded an instruction manual for it and begin a thorough search through it.

Several points were made in the manual, so I investigated much more carefully. Unfortunately, my final determination was that the supply was defective, so I contacted the seller and asked them if they could help me or exchange it (they still have eight more of these units). They asked a few searching questions about my problem solving techniques, and satisfied that I made a good faith effort to make it work, they sent a return authorization and return shipping label.

I've sent it back and I'm waiting for a replacement to arrive. They mentioned sending either a replacement or a refund. I really want a replacement rather than a refund!!! During my study of the instruction manual, I became much more impressed with the power supply and all the features it has. If I get a good, functioning unit, it'll be the number one power supply I use for all my electrochemical experiments and research.

WSM

 

Sadly, the second power supply had the same issue as the first; displayed an AC failure mode (my AC power is definitely within the supply's specifications) and no power output. I also contacted the manufacturer's service department and got some very good suggestions and guidance, but in the end, they also concluded it was a defective unit. The seller took the unit back and refunded my payment, so I gave them a good review.

 

Too bad about those supplies, I really could have used a power supply with that range and all those features.

 

I'm back to using the power supplies I have on hand (which is MANY, just not as versatile as the Sorensen would have been). If I get lucky and find a functional high end unit at a price I'm willing to pay, the scene will be different; but for now, I'll proceed with what I have on hand.

 

WSM

Edited October 20, 2015 by WSM

[50AE]

With such a hot and concentrated cell, I'd be concerned about starting to etch the glass and eventually start poisoning the electrodes with silica.

 

I recall 50AE having some potential problems with this a few years ago. I don't recall if he thought it was because of the glass or fluoride in the water.

 

 

I'm not sure what caused it, but I remember I came to the hypothesis that the lack of power killed the anode. I remember my first cell was a small HDPE bucket.

 

I'm currently thinking of building a new cell, so I was reading the whole thread, searching for "innovative" ideas.

It will be a chlorate bucket cell with MMO/Ti electrodes powered by a SMPS - basically what I've done a few years ago.

I am still thinking about a cheap protection against power failures. Something like an would UPS, but I'd like to know the minimum potential needed between the electrodes in order to protect them.

 

Also, what is the mechanism behind the anode deterioration when unpowered?

 

I'll carry on reading.

[Arthur]

If power outages are really likely in your area then could you make a system to dump the electrolyte away from the electrodes into a catch tank on power failure,

[WSM]

I'm not sure what caused it, but I remember I came to the hypothesis that the lack of power killed the anode. I remember my first cell was a small HDPE bucket.

I'm currently thinking of building a new cell, so I was reading the whole thread, searching for "innovative" ideas.

It will be a chlorate bucket cell with MMO/Ti electrodes powered by a SMPS - basically what I've done a few years ago.

I am still thinking about a cheap protection against power failures. Something like an would UPS, but I'd like to know the minimum potential needed between the electrodes in order to protect them.

Also, what is the mechanism behind the anode deterioration when unpowered

I'll carry on reading.

I think 2.0 Volts DC should work just fine to protect the electrodes. I recall reading something about the cathodic protection starting at somewhere around 1.5 Volts, so 2.0 Volts is a safe minimum to use. A single lead-acid cell delivers two volts; a convenient coincidence.

 

WSM

Edited November 3, 2015 by WSM

[WSM]

If power outages are really likely in your area then could you make a system to dump the electrolyte away from the electrodes into a catch tank on power failure,

I've heard of a few folks using such a system. It would require a pump to move the electrolyte up to the electrode chamber (above the RC) and if the power fails, the electrolyte will drain back down to the reaction chamber.

 

It's an elegant solution to the problem and worth considering.

 

WSM

Edited November 3, 2015 by WSM

[50AE]

If power outages are really likely in your area then could you make a system to dump the electrolyte away from the electrodes into a catch tank on power failure,

 

Although a very reliable way, I think the mechanical stuff will be expensive, such as an electrical valve. It will be clogged from KClO3 crystals though, so a pump might be the next alternative. Or, a lid lift mechanism. The problem is, all materials need to be chlorine/hypochlorite resistant.

 

If 2VDC is a safe potential, I might rely on it as a cheaper alternative.

I haven't practiced chemistry and theory since a long time ago and I've forgotten so much basic stuff.

Does someone have any idea what is the relation between voltage vs. current in a chlorate cell electrolyte? My hope is that it could be non-linear, so that at 2VDC it might draw much less current than at 5DC, so that I might get away with a smaller battery cell.

 

Even if it's linear though, a power failure here doesn't last more than 30 minutes. Let's assume the function is linear and at 5V my chlorate cell draws 20A. At 2,2V lead acid cell (I assume no voltage drop) it will draw 8,8A. A 10Ah cell will be plenty and I'll keep it charged the whole time on floating.

Edited November 2, 2015 by 50AE

[Arthur]

Given a simple bucket cell you could fasten a rope over a pulley with a falling weight to pull the electrodes up after the power failure releases a holding solenoid.

 

Also you could fit a cell with a fair sized drain pipe in flexible PVC held up by a solenoid so that the drain was above the liquor level, Should the power fail the solenoid would release and the pipe fall and release the cell liquor into a catch tank.

 

If you had a second vessel of the same size as the cell you'd be able to get the liquor to flow down from cell to spare tank, then lift the liquor manually or automatically to refil the cell when the power came on again.

 

Could you even use a solar panel? Almost free perc!! My feeling is that some pyros don't need hundreds of kilos from a 50A cell working 24/7/365.

[taiwanluthiers]

You could use solar panels if you won the lottery.

 

You'll need panels, and then batteries to keep the juice flowing when the sun isn't shining. You would also need an inverter to convert the DC power to AC so the solar power could be used with standard appliances. Or you could somehow get the DC output to work directly on the cell, but you still need voltage regulation to work with the uneven output too. If you want maximum efficiency then you need a sun tracking system to keep the panel pointed at the sun at all times.

[Arthur]

200w panel is 40a at 5v, get 12 good hours in the summer and it's free chlorate.

 

I've just revisited Alan Yates pages, http://www.vk2zay.net/article/86may interest some

[taiwanluthiers]

I would caution against using solar power for chlorate production without a backup simply because once the sun stops shining, your anode will be sitting in the solution with no voltage.

[WSM]

Looking at the two preceding posts and those written before, discussing automatic electrode retraction at power loss; a combined setup including all of these ideas would work together to make a (nearly autonomous) solar powered chlorate system.

 

A romantic notion, but one fraught with lots of hitches. Still, if someone wants to pursue this effort, we can offer all manner of suggestions and opinions; and maybe even some material support in the attempt. Let us know .

 

WSM

Edited November 5, 2015 by WSM

[taiwanluthiers]

I just think it's more trouble than it's worth. Having a system to switch over to main power as soon as the sun stops shining seems like additional complexity, not to mention solar panels are expensive. Also the current output will be unsteady, something needs to be done about that. You'll need a big battery for this, which is another cost item.

 

Nothing is free.

[50AE]

It won't be solar powered.

 

I've already ordered two pairs of 2x6" MMO+Ti electrodes from the Amateur Chemist. I have some time thinking about the whole setup

 

Edit: My later thought comes to the measuring pH system. I'm aware that high-end probes have an astronomical cost, also that cheap meters get destructed and paper indicators get bleached. Any suggestions?

Edited November 7, 2015 by 50AE