making potassium (per) chlorate

[Swede]

I wanted to give anyone who is interested in the home pruduction of (per)chlorates a head's up on cell materials.

 

I am convinced PVC plastic and its variants are the ideal cell material, short of a titanium tank. PVC handles low temperatures, CPVC does fine up to nearly 100 C. For a hot portion of a system, such as an electrode cell, CVPC is necessary.

 

My electrode sub-cell is going to be made from a section of 4" CPVC pipe, two end caps, and a series of 316 stainless steel studs.

 

There has been a run on CPVC, or SOMETHING is going on, that has jacked up prices and caused shortages of this material. I went through 6 or 8 suppliers before I found someone willing to sell me a cut section (5 feet) of 4" CPVC schedule 80 pipe. The stuff is $25 per foot, and going up fast.

 

If you think someday you'd like to make a CPVC cell, start lurking eBay now. It is possible to find portions of sheet, cut sections of pipe, fittings, etc, at bargain prices, but it would take possibly weeks to find what you need. I don't want to wait weeks, so I pulled the trigger on the commercial stuff.

 

Also, you'll want Weld-on 724 CPVC cement for both PVC and CPVC, and Weld-on P-70 primer - both of these were engineered by IPS for the chemical industry and are more resistant to chemical attacks than the normal Oatey crap you buy at Home Depot or Lowe's.

 

HTH someone...

[BigTurkey]

First post here (please be understanding!)

 

 

 

A US patent for making Perchlorate in a cell that has a diaphram and using Graphite anode exists.

 

It is US 1279593 and is here

 

 

http://patft.uspto.gov/netacgi/nph-Parser?...p;RS=PN/1279593

 

graphite is not a favourite anode because of the black erosion slop but this patent may break the log jam that seems to exist for the experimenter making Perchlorate. Platinum is too $$$$$, Lead Dioxide is a PITB.

 

A few layers of heavy cloth might do as for the diaphram. This will not work in a Chlorate cell because mixing of the cell contents is necessary when Chlorate is being made.

Has anyone ever tried this??

Pure Chlorate will be needed at the start.

[TheSidewinder]

BigTurkey,

 

Take a look at Swede's Blog. You will most likely get a lot of ideas.

 

There's certainly a lot of good info there!

[tentacles]

First post here (please be understanding!)

A US patent for making Perchlorate in a cell that has a diaphram and using Graphite anode exists.

 

Welcome! That patent has been discussed, and some experimentation done, over at science madness... Unfortunately, the diaphragm must be both conductive, or at least allow the passage of electrons (essentially the same thing, because:) and also prevent the two electrolytes from mixing. Essentially, the diaphragm would have to be a perchlorate anode material.. such as LD, Pt or an exotic Pt based MMO.

 

Swede and I are going to do some experimentation with the current MMO anodes, which are reported to survive in a perchlorate cell - though I'm certain their efficiency at actually making perc is extremely low to nonexistant. What we are going to try is plating them with LD.

[BigTurkey]

I could not find anyone who actually did the cell with the diaphram.

It is like a Chlorine cell (except you use Chlorate and not Chloride). The diaphram has to be some sort of cloth or ceramic that will get soaked by the solution and conduct electricity but not let through cell ions.

A Chlorine diaphram would do, but what could you use. It dosent have to be an anode material.

A red terracotta flower pot with the hole pluged may do.

Edited October 15, 2008 by BigTurkey

[Mumbles]

Cloth isn't going to cut it. You'd probably be looking at a ceramic frit or sintered glass filter of some sort. We were just talking about them today in my lab. Not in relation to chlorate, but same kinda concept.

[tentacles]

Turkey: The thing is, once you find something that will suit the bill - and keep in mind it has to be HIGHLY conductive, or you'll be driving a hundred volts in to get a few amps of current - then you have to pay for it. I think someone did try it using a ceramic of some sort, the problem was the voltage required to drive even a tiny amount of current.

[Mumbles]

What if you had a wide glass tube with the frit at the bottom. You could insert your electrode of choice into here.

 

I'm sorry if I am way off base here, I am at the library, and it won't let me view the patent because I can't install quicktime.

[Swede]

I am not very smart on the use of diaphragms, etc, in electrochemistry, but I did remember seeing an article whereby a druggie was using a lambskin condom as a barrier, with some success with his process. Might be worth a look-see.

[BigTurkey]

I am not very smart on the use of diaphragms, etc, in electrochemistry, but I did remember seeing an article whereby a druggie was using a lambskin condom as a barrier, with some success with his process. Might be worth a look-see.

 

Thanks for replys.

 

Was he the guy on that forum that called himself SheepShagger!!

 

A piece of lamb skin might do.

Ordinary leather.

Asbestos.

Normal portland cement (usually just called cement) perhaps.

A few layers of felt (as sold in cloth shops).

Balsa wood.

 

Wonder would a salt bridge do.

 

What are glass frits? Porus glass?

 

@Tentacles . The diaphram does not have to be made from conductive stuff. When the solution soakes into it, it will be the solution that carries the current. A small amount of ions do move accross the diaphram I suppose.

I am no diaphram expert either.

 

The patent is attached. It is a bit long in the tooth.

 

BT

us1279593.pdf

[tentacles]

And how long do you expect lambskin to last in a perchlorate cell? Or cement - do you really want to go adding an essentially everlasting pH bufer to the cell, not to mention the calcium ions? There isn't a single material on your list that I would get near a (per)chlorate cell.

 

If the diaphragm material isn't conductive, it will either pass too much electrolyte "felt" or present too much resistance "ceramic". Organic materials have the problem of not surviving long in a perch cell, and being explosively flammable after a long soak in perc. Frits, I think you would have the problem of them clogging up or being too coarse. Are there actually glass/ceramic frits that are practically osmotic membranes?

 

Remember, these cells are driven with carbon electrodes, so you'll have plenty of pore-seeking carbon floating around to hose up the works. There was some discussion that if C works, an ordinary MMO anode might also work.

 

It might still be worth trying if you're up for it. I have my doubts that the patent even works, though. That's the thing about perchlorate patents... a lot of them are BS.

[Swede]

I was tossing out the lambskin condom suggestion as an idea for other barrier/diaphragm processes. I agree that it's life would be short in a chlorate cell. Hell, just about everything has a short life in one of these cells.

 

Nickel plating was one process that required some sort of barrier over the nickel metal electrode to prevent what they called "smut" on the finished, plated item. I don't remember what the original user was making, some sort of illegal drug, but it seemed to be a clever idea.

[WarezWally]

Have we had any success in making a decent anode for perc production? Still got all my gear sitting around in boxes somewhere

[Swede]

Haha, hundreds (probably thousands) of enthusiasts have been flogging this problem for years. I'm playing catch-up with the theory.

 

I've been corresponding w/Tentacles, who is vastly more experienced than me on the theoretical side. I've picked up an entire sheet of "special" MMO mesh... it's special in the sense that the MMO coating has been tweaked through years of research to survive brutally low chloride concentrations. If we can plate lead dioxide onto it, it should make perc, and should have a decent lifespan.

 

Here's some fun and interesting pics from a commercial (per)chlorate plant. A massive chlorate anode:

 

http://www.5bears.com/perc/comm01.jpg

 

Note that the anodes are MMO. Research on chlorate MMO anodes has essentially halted, because what they currently have performs so well. But they keep chloride levels high, which is gentler on their anodes, and it is a very precise and well-known process, unlike a hobby setup which is less than optimum.

 

And the gaint cells they go into... (I wish I knew what the cells were constructed of):

 

http://www.5bears.com/perc/comm02.jpg

 

For perchlorate, it's platinum foil, not PbO2. They can afford to do this because they have Pt recovery techniques. Pt for home use is still practical, but expensive. A beautiful Pt anode, connected to a "spine" of some sort of coated metal, perhaps MMO coated.

 

http://www.5bears.com/perc/comm05.jpg

 

Back to the "special" MMO mesh. Pool chlorination MMO materials have been pooh-pooh'ed for years by hobbyists, I believe incorrectly. Makers of pool chlorinator MMO anodes have to contend with end users who are morons. A normal salt pool runs at 3,000 ppm chloride ion, very low indeed, yet the anodes work fine. The current densities are low, which helps, but still, they must create anodes that not only won't be damaged by users who try and run at 200 ppm, they also must survive polarity reversal to clean them, which is tough to do. There's a lot of recent science in the modern chlorinator MMO compositions, moreso than those made for chlorate plants. I believe these anodes will work well in a home setup.

 

A lot of this information has come from a knowledgeable guy who found my blog (see? it pays to blog! More blogs, dammit! ) who makes pool chlorinators in Australia, and is a pyro himself.

 

Our hope is that these anodes will not only make chlorate with ease to low chloride ion concentrations, if the MMO surface can take a plating of PbO2 that will adhere and be durable, it'll be an economical and useful perchlorate anode.

[WarezWally]

I see not much has changed

 

I thought of plating my MMO anode (commercial chlorate design) ages ago but never got around to it, I have all the gear required but I have no need for perchlorate / chlorate anymore. Still got a massive cell half full of precipitated potassium chlorate sitting around in the garage. Has been there for many months

 

All of my research points towards it working (well the PbO2 adhering relatively well) and if it does have a hole it will eat away at the MMO and then hit the titanium where it will be stonewalled so to speak.

Edited October 19, 2008 by WarezWally

[Swede]

All of my research points towards it working (well the PbO2 adhering relatively well) and if it does have a hole it will eat away at the MMO and then hit the titanium where it will be stonewalled so to speak.

THAT is exactly what we are hoping to avoid with this "Super MMO" material. The guy who found it said he started one cell with chloride stock and simply let it go indefinitely, in an attempt to do the chloride --> chlorate --> perchlorate in one process. No effect on the MMO. On another cell, he cranked the amps up and ultimately boiled the cell dry, again, no ill effect on the coating.

 

Hopefully that'll be the case, and a modest plating of lead dioxide will see the anode making perc economically.

 

I have no idea why this process has influenced me so strongly... I just can't let it go. I refuse to add up the $$ I've spent trying to make something that sells for $5 - $10 lb, especially when I am NOT currently a heavy user of it. I guess it's the challenge of it, and the satisfaction you get creating a pure product cheaper than the commercial stuff.

[BigTurkey]

_SWEDE_

 

You need to stop calling this process a hobby, project, obsession etc.

 

IT'S A CRUSADE :-| (a vigorous campaign in favour of a cause, as defined by Oxford dictionary)

 

 

> Hopefully that'll be the case, and a modest plating of lead dioxide

> will see the anode making perc economically

 

Put on a thick coat while you are at it.

 

Could you ask your commercial Perchlorate maker friend if commercial Perk. cells are ph controlled and what additives are added to the cells.

[tentacles]

Put on a thick coat while you are at it.

 

Could you ask your commercial Perchlorate maker friend if commercial Perk. cells are ph controlled and what additives are added to the cells.

 

Thick coats get lots of internal stresses and can simply crack and flake off.. there's a balance somewhere between long lasting and not self destructing.

 

The guy doesn't make perc commercially, he makes/sells anodes for other processes.

 

- anyways -

 

Been busy today.. warning, pictures are huge! I got my new camera the other day..

 

http://www.pyrobin.com/files/sdc10030_1.jpg

http://www.pyrobin.com/files/sdc10033.jpg

http://www.pyrobin.com/files/sdc10036.jpg

 

That's the MMO anode coated with .25mm of lead dioxide. It's just a thin coat at this point to test the process and see if it works in an actual cell. Now I've just gotts build a cell! There's a place nearby with lots of big PVC, I may just see about acquiring a couple feet of 12" PVC for this project. Otherwise, bucket time!

 

Er, since when did the attachments stop working? I hit upload and it seems to go through but there's nothing listed under manage current attachments.

Edited November 12, 2008 by tentacles

[TheSidewinder]

Attachments better NOT have stopped working!

 

I'll take a look at it. But what size were the uploads?

 

 

 

 

EDIT: OK, those really ARE huge pics. That's the reason. We have a 4mb TOTAL upload limit for attached pics in one post.

 

I'll remove the limit for all donators. Try reposting them here and let me know if it still won't work.

[TheSidewinder]

OK, the per-post attachment upload limit is removed for all Donators (though there is a "host-imposed" 64mb limit).

 

I assume no one is going to abuse it.

[Arthur]

Does anyone have, that they can share, a good system of classical wet analysis for the perc cell process?

[tentacles]

I'm not sure what you're asking for here? The reactions that take place in the conversion of chlorate to perc? Or something?

[Mumbles]

He's talking about wet chemistry techniques to provide an analysis for purity and contaminants I would imagine. These are generally limited to qualitative analyses unfortunately. If only everyone had and ICP-AES handy.

 

I have a few ideas, but I have to run at the moment. I'll try to provide some links to proceedures, or at least some references later this evening.

[Arthur]

If I set up a perc cell, I want to test the final product for purity, and test the intermediate products for purity and yield.

 

I was proposing a two stage system with carbon electrodes for the chlorate cell, then precious metal or special oxide electrodes for the perc stage. then I want to test the chlorate content and perc content in the final solution, so that I can run safely without damaging the electrodes or destroying too much ClO3 to purify the perc.

 

I started looking at ion selective electrodes but there initially seemed to be a lot of interfering species in the cell anyway.

[Mumbles]

There are a few qualitative tests you can do. The most accurate way would probably be to make a series of know analyses to test against.

 

Chloride would be best tested for with AgNO3 or Pb(NO3)2. A series of knowns, say from 1-100ppm could be produced and used to compare levels of cloudiness. Not sure how sensitive it would be.

 

A similar thing could be done with Chlorate using one of the various organic dye tests.

 

If you want to get quantitative, and can source a buret, this is an option.

http://www.geocities.com/CapeCanaveral/Cam...titrations.html