Electroplating PbO2 onto titanium electrodes

[LardmanAttack]

For now i'll be simply making KClO3 from KCl as the process is very simple, but I would eventually like to make perchlorates, this is difficult to do and a platinum electrode won't even cut it, i've heard, although people say that it won't corrode too much if the Chlorate levels drop too far in the cell, but this would still heavily contaminate any Perc I make with chlorates, I'd like to get around this altogether by just using a lead dioxide electrode, the problem is that I don't have one and don't know where to easily get one, So I'd like to make one but don't even really know where to start, I know that you use a solution of a lead salt and pass current through that but how would I stop buildup of side products in solution and stop lead from plating out instead of Lead dioxide.

Edited April 10, 2019 by LardmanAttack

[Arthur]

The history of solid fuel rocketry is full of KP that has been made electrolytically from using (in part) a platinum electrode. There is much research between you and a successful product but it is possible. Try to read ALL of "Swede"s blog. Try to read ALL of the huge thread "Making (per)chlorates"

www.amateurpyro.com/forums/topic/1629-making-potassium-per-chlorate/page-1

 

Without studying all of that you will not be up to speed on past discussions and will annoy people asking for the info already contained in that monster post.

 

If you wish to progress to perc, you should start using sodium chloride, it's much easier on the electrodes.

Edited April 14, 2019 by Arthur

[LardmanAttack]

 

The history of solid fuel rocketry is full of KP that has been made electrolytically from using (in part) a platinum electrode. There is much research between you and a successful product but it is possible. Try to read ALL of "Swede"s blog. Try to read ALL of the huge thread "Making (per)chlorates"

www.amateurpyro.com/forums/topic/1629-making-potassium-per-chlorate/page-1

 

Without studying all of that you will not be up to speed on past discussions and will annoy people asking for the info already contained in that monster post.

 

If you wish to progress to perc, you should start using sodium chloride, it's much easier on the electrodes.

Yeah, checked on there, and nowhere on that thread has properly laid out instructions on how to plate

PbO2

Edited April 18, 2019 by LardmanAttack

[LardmanAttack]

Even if there is info in there, I'm not really gonna spend an hour reading it all.

[Mumbles]

I'd be very impressed if you could make it through that thread in an hour. On the other hand, if you're not willing to put in the work and research on your own, especially if the information is there, you might find people will become a lot less willing to help you.

[Arthur]

An electrolysis cell will cost you money, you need to do adequate research to justify the spend. This forum has lots of info and google can point you to patent documents and university research projects, but you have to put the time in to read all there is and understand it all. No one person here knows it all, and no one will simply present you with a cookery recipe to make whatever you want. Once you understand the process, then you need to work out what materials are available in your locality that may be a good start for your project. Once you have a process design to suit your available raw materials then you need to work out what safety issues there are and what precautions and protection are needed.

 

Then you have to hope your theory translates well into practice.

[WSM]

Yeah, checked on there, and nowhere on that thread has properly laid out instructions on how to plate

PbO2

If I remember correctly, Swede succeeded in plating hard crystalline lead dioxide on MMO electrode material, bypassing the difficult step of properly preparing the CP titanium substrate.

 

Later, he did a trial run using the LD anode, and did indeed make perchlorate with it.

 

At this moment, I don't recall where he wrote about it, but I suspect it may be found in his BLOG posts.

 

Good luck.

 

WSM

[Arthur]

Swede's forum posts and blog posts contain all of his expensive and time consuming experimental work, it would be a waste of both time and money not to read all of his work before proceeding with any perc cell work.

 

Other literature may exist online into older perc processes using platinum electrodes -which are easier to make but need careful handling, and some cash! Fortunately the current used in a chlorate cell is very much more that the current used in a perc cell so only moderate platinum electrodes are needed.

[WSM]

The biggest problem with using platinum to make perchlorate is if the CHLORIDE levels are too high. Chlorides are hard on platinum anodes.

 

Chlorate, on the other hand, isn't hard on them. The easiest approach is to use sodium chlorate solution and electrolyze it to sodium perchlorate.

 

After removing any residual chlorate, then the perchlorate solution is ready to be converted to other useful perchlorates, such as potassium or ammonium perchlorate.

 

I've only ever made potassium perchlorate from the sodium perchlorate solution I've produced.

 

WSM

[WSM]

Yeah, checked on there, and nowhere on that thread has properly laid out instructions on how to plate PbO2

 

Somewhere in my computer files, I have a description from Swede of the processes he used to successfully plate hard crystalline lead dioxide into CP titanium.

 

To avoid the difficulty of preparing the titanium plate, he used MMO on titanium mesh as a foundation to plate onto.

 

The lead plating was thick and heavy.

 

In use, the only problem with the electrode was with the LD nodules dropping off the uncoated edge of the MMO. The rest of the electrode held up well.

 

Swede also converted potassium chlorate to potassium perchlorate.

 

The issue with that is, potassium chlor-alkali salts decrease in solubility as the oxygen levels increase, BUT sodium chlor-alkali salts increase in solubility as the oxygen levels increase.

 

This means that, though both sodium and potassium chlorides are nearly identical in solubility, the perchlorates of them are about 100 times different from each other (potassium perchlorate is roughly 1% the solubility of the sodium perchlorate).

 

So, fine crystalline potassium perchlorate immediately drops out of solution when KCl solution is added to sodium perchlorate solution!

 

The big challenge after the KClO4 is produced is to completely remove sodium contamination before drying and storing the desired product.

 

WSM

Edited May 16, 2019 by WSM

[WSM]

Yeah, checked on there, and nowhere on that thread has properly laid out instructions on how to plate PbO2

Check again. Swede's blog (you'll shoot your eye out) on 16 January 2009.

[Arthur]

The professional perc process is to take sodium chloride (salt -food grade is OK) electrolyse it to sodium chlorate, then boil it down to about half volume and harvest the crystals of chlorate that form on cooling. These crystals are then dissolved in hot water and electrolysed a second time against a platinum electrode to turn the chlorate into perc. Then you add a saturated solution of K (or other) chloride. This forms sodium chloride which you reuse, and your desired perchlorate as a precipitate.

 

The titanium and MMO electrodes are for long term use -maybe good for several years

the platinum and titanium electrodes don't like chlorides -given chlorides the platinum electrode will wear. The professionally quoted wear rate is 2 - 10 grammes or Pt erosion per ton of perc.

 

Whatever current you use for the process to chlorate you will need about 20% of that current on the platinum electrode. A 1" square Pt electrode can be sourced from a jewelery suppliers. Titanium rods are an ebay item as are MMO and Ti sheet.

[WSM]

 

The titanium and MMO electrodes are for long term use - Titanium rods are an ebay item as are MMO and Ti sheet.

 

Be sure to source "CP" titanium, which is commercially pure. Titanium Alloys don't hold up in the "anodic hell" (to quote Swede) of the chlorate cell, plus alloys may introduce unwanted metal ions to the electrolyte.

 

WSM

[WSM]

The professional perc process is to take sodium chloride (salt -food grade is OK) electrolyse it to sodium chlorate, then boil it down to about half volume and harvest the crystals of chlorate that form on cooling. These crystals are then dissolved in hot water and electrolysed a second time against a platinum electrode to turn the chlorate into perc. Then you add a saturated solution of K (or other) chloride. This forms sodium chloride which you reuse, and your desired perchlorate as a precipitate.

 

 

Actually, I avoid food grade salt as most have additives which become contaminants in the final product.

 

I've had better luck with water softener grades of salt (either sodium or potassium), but even then I recommend purifying the brine before electrolyzing it, so that the end product will be purer.

 

The typical commercial method of purification involves treating the raw brine (NaCl in this case) with a mixture of sodium carbonate and sodium hydroxide solutions, which drops out many contaminants (calcium, magnesium and iron, for example) as flocculant precipitates, which can be filtered out, leaving a more pure brine.

 

I've found the best filtration method to be vacuum filtration using a slow grade of laboratory filter paper (hardened is a good idea, also) since the precipitates are very fine.

 

Also, any excess alkalinity in the purified brine can be neutralized with dilute HCl to leave a neutral to slightly acid solution, ideal for electrolyzing into oxidizers. Neutral brine is best for conversion to other salts, as is the case of converting sodium perchlorate into potassium perchlorate.

 

NaClO4(aq) + KCl(aq) -> NaCl(aq) + KClO4(s)v

 

By taking the extra steps to purify all the materials used, I believe better-than-commercial grade oxidizers can be produced.

 

WSM

Edited May 27, 2019 by WSM