making potassium (per) chlorate

[WSM]

You can certainly lose some current by using longer leads. Short leads have low resistance longer leads have higher resistance at the currents involved 10 milli ohms is a reasonable current limiter. Copper covered aluminium is higher resistance than pure copper of the same size

https://www.ebay.com/itm/224781949981 May be interesting but may be 230vac.

https://www.ebay.com/itm/265854333787 cheap but 5A max.

Other options exist!

Remember that overdriving the electrodes (esp the anode) will stop things working.

 

 

Using tubular CP titanium leads connected to my electrodes, I find that a copper core (bare, solid copper wire) inside the Ti reduces the resistance of the leads and keeps the cell running cooler (Less hot, actually).

 

WSM

[cmjlab]

Silly question - is spot welding the only way to make changes to a platinized titanium lead? (For example I wish to make a longer lead by adding a titanium extension) The machine at HF still costs ~$140 last time I looked, and I'd have limited to no use for it after that I can think of. I'm assuming any attempt to bolt the two pieces together would lead to excessive rust until eventual failure (probably pretty quickly too).

[Arthur]

In post 5399 of this thread I'm referring leads as the flexible wires leading to the integral hangers of the electrodes. The integral electrode hangers are rigid but the flexible wires can be chosen for diameter length and material to increase or decrease the resistance and (inversely the current.

 

The heating effect of the electrolysis is useful to maintain a temp between 50 and 60 Celsius

Edited August 30, 2022 by Arthur

[WSM]

Silly question - is spot welding the only way to make changes to a platinized titanium lead? (For example I wish to make a longer lead by adding a titanium extension) The machine at HF still costs ~$140 last time I looked, and I'd have limited to no use for it after that I can think of. I'm assuming any attempt to bolt the two pieces together would lead to excessive rust until eventual failure (probably pretty quickly too).

Spot welding works well for a fast, permanent bond but it's not the only way to attach CP titanium leads to electrodes.

 

If you can find or fabricate rivets of CP titanium, that would work also.

 

If you can source CP titanium wire, you can "stitch" the parts together.

 

If you have access to a microwave oven Transformer, there are instructions online to convert it into a spot welder.

 

WSM

[cmjlab]

Yeah you can imagine my disappointment when I realized that (looking around YouTube I did see several spot welder tutorials), having recently disposed of a bunch of junk I would "never use".....a microwave with working transformer! We got tired of switching out microswitches on door, so we bought a new over the counter microwave and tossed the old one.

 

Charles

[cmjlab]

Appreciate the other methods though, looking at those prices I'd prob be better off just snatching an junk microwave back from the dump in my next trip to dispose of more useless items!

 

Charles

[Arthur]

A true spot welder is a transformer to give about 2v at huge currents directly off the mains. Many a "spot welder" for nickel strip and lithium batteries is a capacitor bank charged slowly and discharged in a flash. A MOT spot welder may be just what you want.

[markx]

Silly question - is spot welding the only way to make changes to a platinized titanium lead? (For example I wish to make a longer lead by adding a titanium extension) The machine at HF still costs ~$140 last time I looked, and I'd have limited to no use for it after that I can think of. I'm assuming any attempt to bolt the two pieces together would lead to excessive rust until eventual failure (probably pretty quickly too).

Curiously enough you can just use a pressure connection to join CP parts on the anode side of the cell (obviously the cathode side is also going to work ok). I have a split in a CP anode stem that I just force the platinized titanium plate into. If the plate passivates or becomes nonoperational for some reason, then I break it out of the slot and replace/regenerate the working part. Very convenient and against all intuitive reason, as the pressure contact between the stem and plate should passivate very quickly and break the connection or at least disrupt the flow of current seriously. But none of such happens and I've made several successful perchlorate conversions stretching into weeks with the setup. Does not matter if the connection is submersed under cell liquor or not....seems to work well both ways.

[WSM]

Curiously enough you can just use a pressure connection to join CP parts on the anode side of the cell (obviously the cathode side is also going to work ok). I have a split in a CP anode stem that I just force the platinized titanium plate into. If the plate passivates or becomes nonoperational for some reason, then I break it out of the slot and replace/regenerate the working part. Very convenient and against all intuitive reason, as the pressure contact between the stem and plate should passivate very quickly and break the connection or at least disrupt the flow of current seriously. But none of such happens and I've made several successful perchlorate conversions stretching into weeks with the setup. Does not matter if the connection is submersed under cell liquor or not....seems to work well both ways.

 

 

That makes sense when we consider the electrolyte itself is conductive and part of the electrical circuit of the cell. I suppose that's why simply "stitching" the electrodes to the CP titanium parts of the cell with thinner CP titanium wire works (as reported by someone here, many years ago).

 

Thanks for sharing your experiences with non-welded components of your cells.

 

WSM

[WSM]

In post 5399 of this thread I'm referring leads as the flexible wires leading to the integral hangers of the electrodes. The integral electrode hangers are rigid but the flexible wires can be chosen for diameter length and material to increase or decrease the resistance and (inversely the current.

 

The heating effect of the electrolysis is useful to maintain a temp between 50 and 60 Celsius

 

 

Ah, I see. Sorry for my misunderstanding of your comments.

 

It's at times like these that I see the weakness of our words in communicating our thoughts and concepts. It is confusing when I use the word lead [pronounced led](elemental Pb) and lead [pronounced leed](electrical wire or connection), sometimes in the same sentence!

 

I presume by "hangers" you mean the rigid CP titanium connections added to the electrodes (inside the cell) which convey current from the pliable electrical leads (outside the cell) coming from the power supply.

 

In common electroplating scenarios, the term "hangers" is more apt, where items being plated are suspended from bus bars above the tank by electrically conductive hanger wires. I suppose we need a more accurate term to describe the methods and materials we use to extend the reach of our electrodes from the corrosive environment inside our cells, to the safer environment outside the cells, electrically speaking.

 

I'm open to suggestion here. It's helpful to use our own terminology so as to avoid confusion, and clearly convey our meaning and intent when discussing electrochemistry.

 

WSM

Edited September 1, 2022 by WSM

[cmjlab]

I appreciate all of the responses, seams there are some interesting alternatives to spot welding.

 

Though if I had a decent spot welder and setup I could branch into poss. more efficient ematch manufacture with potentially less waste of nichrome wire (as true nichrome wire appears to be going up in price since it's used by the vape community as well, though not in as small of a guage).

 

Excellent layout of info on the cell setup WSM (I finished reading the 1-4 parts of I hadn't told you already). I appreciate you taking the time to write all that info up and preserve it here where I am able to read it without an expensive university subscription).

 

Charles

[WSM]

Though if I had a decent spot welder and setup I could branch into poss. more efficient ematch manufacture with potentially less waste of nichrome wire (as true nichrome wire appears to be going up in price since it's used by the vape community as well, though not in as small of a guage).

Excellent layout of info on the cell setup WSM (I finished reading the 1-4 parts of I hadn't told you already). I appreciate you taking the time to write all that info up and preserve it here where I am able to read it without an expensive university subscription).

Charles

Actually, spot welding a bridgewire to a piece of PC board material is no trivial task. MANY problems present themselves in any attempt to do so.

 

Once in the past, I had occasion to work for a robotic fabrication firm that built automated assembly machines designed to build automotive airbag initiators from beginning to end without human contact.

 

The trickiest part was building a machine to spot weld the bridgewire to a base blank without burning the bridgewire in the process.

 

They accomplished this feat by applying a miniscule amount of a volatile solvent to the bridgewire before the welding step, which flashed off during the weld, cooling the wire enough to prevent any damage to it.

 

On my own, of the hundreds of attempts I've made in spot welding a bridgewire, only one ever succeeded.

 

I find that soldering them is much more successful than spot welding (without a LOT of extra effort, that is)!

 

WSM

Edited September 2, 2022 by WSM

[cmjlab]

I guess based on that I'd agree with your sentiment, might as well solder'em then. Equipment is def cheaper that way!

Charles

[WSM]

I appreciate all of the responses, seams there are some interesting alternatives to spot welding.

Though if I had a decent spot welder and setup I could branch into poss. more efficient ematch manufacture with potentially less waste of nichrome wire (as true nichrome wire appears to be going up in price since it's used by the vape community as well, though not in as small of a guage).

Excellent layout of info on the cell setup WSM (I finished reading the 1-4 parts of I hadn't told you already). I appreciate you taking the time to write all that info up and preserve it here where I am able to read it without an expensive university subscription).

Charles

 

 

I was encouraged by Swede to contribute my efforts here (as he was also doing). Swede used these posts as well as his blogs, as a sort of lab book to store his notes in a place accessible to us all, so we all can benefit from his experience along the "chlor-alkali, electrochemical" trail.

 

I think I'm following in his footsteps in that regard. I'm trying to document my research so others can learn from my experiments, and have a clue where to start. I'm documenting these things so others can avoid the pitfalls and errors I've made, and see what has been successful.

 

I'm trying to learn and share the information I wish I could have found when I started all of this, many years ago.

 

WSM

Edited October 18, 2022 by WSM

[WSM]

I've begun revisiting the incomplete Part 18 of the Homegrown Oxidizers series.

 

The beginning of part 18 was in 2016. It has languished on my computer desk top over seven years, but keeps calling to me...

 

The series stalled after a failed attempt to build a workable high temperature sodium chlorate cell using high-end polymers. The problem was getting a liquid-tight seal on the bottom of the cell. I believe the issue was getting a proper seal on the tubular titanium electrode leads. Since the cell was a tall PVDF tube, I tried to save on expensive metals by placing the electrode entry to the cell through the bottom plate.

 

The PVDF fittings couldn't get a proper seal with the head pressure of the liquid column above it (more or less 4", or more than a meter of height), so the water fill I was testing the tank with, kept leaking.

 

I've since decided to use a large laboratory flask as a cell body for the high temperature cell. The only issue was the borosilicate (Pyrex) glass vessel can't tolerate high alkalinity, so I intend to use active pH control in the experimental cell. This cell will likely be the topic in Homegrown Oxidizers, Part 19. The ultimate goal of the sodium chlorate cell is to produce a large quantity of pure sodium chlorate crystals, which will be used to make the electrolyte (with distilled or deionized water) for a sodium perchlorate cell and continue my perchlorate experiments.

 

The main topic of Part 18 is obtaining purer oxidizers by purifying the starting brine. The idea occurred to me when reading an article by an industrial chlorate manufacturer briefly describing their process for sodium chlorate production. They start with barge loads of raw salt which is mixed with water to form the raw brine.

 

The raw brine is treated with sodium carbonate and sodium hydroxide to cause the common contaminants (calcium chloride and magnesium chloride) to precipitate and drop out of solution. I used a similar process to purify water softener salt (NaCl) before doing the first run of the sodium chlorate cell back in 2016. I dissolved the salt in distilled water by pumping the water through the course crystals in a large polymer tank I set up for the purpose, using a motorized chemical pump.

 

Once the salt was dissolved, I noticed solid chunks of stone and rust scale in the bottom of the tank. Also, there was a fine tan colored silt on the tank floor. Using a benchtop Buchner funnel and lab filter paper, I removed the visible contamination and deposited the clear brine into new 5 gallon (about 19 liter) polyethylene (PE) buckets.

 

After filtering out the visible contaminants, I wondered what invisible contaminants were left in my clear brine? I made up a quantity of 1M sodium carbonate solution and applied about 350 ml of it to a full bucket of brine and the whole thing instantly turned milky white. I covered the bucket with a lid, let it sit for a day and found the precipitated contaminant had settled to the bottom of the bucket.

 

Next, I carefully decanted the clear brine into another new bucket and afterward vacuum filtered the residue in the reaction vessel bucket through a "slow" grade filter paper with very fine pores, due to the extremely fine particles of precipitates (primarily calcium carbonate and magnesium hydroxide). A freshly-prepared sodium carbonate solution seem to also form a bit of hydroxide when water is mixed in, adding to the alkalinity substantially!

 

I tested the pH of the purified (calcium, magnesium and iron-free) brine and found it too high (alkaline) for my plans. I next treated the brine with dilute (about 1M) hydrochloric acid (made from pool acid and distilled water), till the brine was neutral (pH 7.0) to slightly acidic (pH 6.8), perfect for a chlorate cell.

 

My purified brine ran in the sodium chlorate cell for about six weeks (till the calculated end-of-run) and the resulting harvested NaClO₃ crystals where gem-like in appearance, due to their purity.

 

After all the effort to make purified sodium chlorate crystals to be used in making sodium perchlorate solution by electrolysis, it seemed a shame to react it with an impure solution of potassium chloride to make potassium perchlorate.

 

The focus of Part 18 is to make and purify potassium chloride solution, for use as an electrolyte in potassium chlorate cells, and as a pure reactant for use in turning purified sodium perchlorate into high quality potassium perchlorate.

 

That's the plan, and I'll post the efforts and results here as I progress toward preparing the article (to be published in the PGI Bulletin). I intend to post photos of the steps here, as well.

 

WSM

Edited January 30, 2023 by WSM

[cmjlab]

Did you ever figure out what the contaminants were? I would have though water softener salt had to be relatively pure to be used in water softener systems, as that would be meant for human consumption (though this is clearly not the case).

 

Though this is purely speculative and theoretical on my part - wouldn't starting from Potassium Chloride be the most efficient route to get to KCLO4, and ensure zero (or close to) sodium contamination in your final product? (Which I see you opted for in the end). My point is that though the sodium chlorate was a good proof of concept, you wouldn't want to start from that for product you'd actually use in pyro right, due to all of the issues potential sodium contamination causes.

 

Moving away from the speculative.... :-), let me know when you get your first crop of "ultra pure" chlorate and I'll buy some from you (if that's legal).

 

I'm curious to see the difference of actual "high purity" oxidizer, compared to commercial "high purity" with at least some sodium / chloride contamination.

 

Charles

[Arthur]

Sadly the solubilities of the potassium salts are too low to enable good electrolysis. The professional method is always to electrolyse sodium chloride and precipitate the product potassium salts and extract by (ice)cold filtration.

 

The point of the thread here and the PGI articles is to enable people to make their own. In fact once started the process needs no attention for one or more weeks, just feed it electricity.

[cmjlab]

Sadly the solubilities of the potassium salts are too low to enable good electrolysis. The professional method is always to electrolyse sodium chloride and precipitate the product potassium salts and extract by (ice)cold filtration.

 

The point of the thread here and the PGI articles is to enable people to make their own. In fact once started the process needs no attention for one or more weeks, just feed it electricity.

Ill accept the Potassium salt solubility/conductivity issue, I hadn't considered that.

 

As for the point of "making it on your own", I don't really want to get a whole setup to make my own due to many factors, mainly space for hobbies. I also don't want to go into production of chlorate / Perchlorate just to find out if it is indeed better than commercially available purity.

 

I thought the main point of this thread and PGI articles (never seen those) was so that people who couldn't buy their own could make it. I don't see how the purchase of quality equipment needed, and periodic maintenance / replacement (i.e. expensive rare metal / MMO / lead anode) could be that much more cost efficient than current prices commercially.

 

I don't really expect anyone to sell me any quantity unless they wanted too, I don't even know if it's legal - and I'm not looking to do anything that invites more scrutiny of myself or fellow hobbyists.

 

I appreciate the info on the Potassium salt solubility though, again I hadn't considered that aspect.

 

Charles

[Arthur]

Your opinion is valid as long as USA regulations permit. In the UK and Europe most oxidisers and poisons are now banned by law. So either you have a licensed factory or you go to a professional firework display.

[WSM]

Did you ever figure out what the contaminants were? I would have though water softener salt had to be relatively pure to be used in water softener systems, as that would be meant for human consumption (though this is clearly not the case).

Though this is purely speculative and theoretical on my part - wouldn't starting from Potassium Chloride be the most efficient route to get to KCLO4, and ensure zero (or close to) sodium contamination in your final product? (Which I see you opted for in the end). My point is that though the sodium chlorate was a good proof of concept, you wouldn't want to start from that for product you'd actually use in pyro right, due to all of the issues potential sodium contamination causes.

Moving away from the speculative.... :-), let me know when you get your first crop of "ultra pure" chlorate and I'll buy some from you (if that's legal).

I'm curious to see the difference of actual "high purity" oxidizer, compared to commercial "high purity" with at least some sodium / chloride contamination.

Charles

 

 

Hi Charles,

 

The contaminants are calcium, magnesium and any soluble iron salts present. Those are the things in water that make it "hard"! They're common in most salt, and what make Himalayan and sea salts healthier than iodized table salt (with all the added "free-flow" etc. contaminants deliberately added). Even pool salt (labeled as "pure"), for salt water chlorination systems, has calcium and magnesium contamination (although less than typical water softener salt). I proved this myself with chemical testing.

 

Potassium chloride to potassium perchlorate? If only it were that easy. Industry proved long ago that path isn't cost effective, so they go the sodium perchlorate route, with purification to get extremely low sodium levels in the final product.

 

Very little sodium will ruin many colors in colored stars due to the highly luminous sodium ions, which is why sodium vapor lamps are used. Industry washes the freshly-made (and very low solubility) potassium perchlorate powder with lots of water, to wash away the highly soluble sodium contamination before drying and packaging the perchlorate. Too much sodium contamination not only ruins colors, it adds a hydroscopic nature to impure potassium perchlorate, so it must be removed for the product to be commercially viable.

 

After I produce a little (I work in small, experimental quantities), I can give you a sample to test if we meet in person. I don't sell or ship it .

 

Thanks for asking.

 

WSM

Edited January 30, 2023 by WSM

[WSM]

Sadly the solubilities of the potassium salts are too low to enable good electrolysis. The professional method is always to electrolyse sodium chloride and precipitate the product potassium salts and extract by (ice)cold filtration.

The point of the thread here and the PGI articles is to enable people to make their own. In fact once started the process needs no attention for one or more weeks, just feed it electricity.

 

 

True. Sodium perchlorate is almost exactly 100 times more soluble than Potassium perchlorate.

 

WSM

[WSM]

Ill accept the Potassium salt solubility/conductivity issue, I hadn't considered that.

As for the point of "making it on your own", I don't really want to get a whole setup to make my own due to many factors, mainly space for hobbies. I also don't want to go into production of chlorate / Perchlorate just to find out if it is indeed better than commercially available purity.

I thought the main point of this thread and PGI articles (never seen those) was so that people who couldn't buy their own could make it. I don't see how the purchase of quality equipment needed, and periodic maintenance / replacement (i.e. expensive rare metal / MMO / lead anode) could be that much more cost efficient than current prices commercially.

I don't really expect anyone to sell me any quantity unless they wanted too, I don't even know if it's legal - and I'm not looking to do anything that invites more scrutiny of myself or fellow hobbyists.

I appreciate the info on the Potassium salt solubility though, again I hadn't considered that aspect.

Charles

 

 

The solubilities (and other factors) drive the way things are done industrially.

 

The scale of these things can be quite small and still produce workable amounts for an amateur. The quality of the setup has more to do with the longevity of the system than the quality of the products. Skills are the major achievement gained from the effort, and those are priceless in a world of diminishing availability of materials.

 

WSM

[WSM]

Sadly the solubilities of the potassium salts are too low to enable good electrolysis. The professional method is always to electrolyse sodium chloride and precipitate the product potassium salts and extract by (ice)cold filtration.

The point of the thread here and the PGI articles is to enable people to make their own. In fact once started the process needs no attention for one or more weeks, just feed it electricity.

 

 

I forgot to mention, over a decade ago, Swede tried the potassium chlorate to perchlorate route. He proved it's possible, just not practical. The potassium perchlorate, being almost insoluble, dropped out of solution as it was formed and jammed the electrodes with crystals (reducing the efficiency greatly).

 

WSM

Edited January 30, 2023 by WSM

[Arthur]

Electrolysing potassium salts works in theory BUT it's very hard on the electrodes, especially when using platinum electrodes this is undesireably expensive.

[cmjlab]

I appreciate the response. Arthur also pointed out the solubility issue as well. I never even considered it.

 

On a different topic (and if you addressed this already, I apologize) I've only read Parts 1-5 or 6 of your overall thread so far: is the lead dioxide or lead something anode a viable homemade option? I vaguely recall reading or watching a YouTube video about making your own anode with some lead product, but can't recall feasibility or if it was even successful. It's the platinum / rare metal blend anode that's so expensive, which I've read will need to be replaced periodically, that has really prevented me from trying this at any scale.

 

I'm still following along with interest though!

 

Charles

Edited January 30, 2023 by cmjlab