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Author: Subject: chlorate/perclorate cell help for an amature
frosty90
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[*] posted on 8-1-2010 at 03:46
chlorate/perclorate cell help for an amature


Hi all,

Im a beginner here so be gentle...

I would like to build a cell for produceing potassium per/chloratem, and Im willing to spend a bit of money. A while ago I made an attempt with sodium chlorate, using graphite anodes. I ran the cell for about weeks, at about 10 amps, and got bugger all product, but a load of graphite mud. I did keep the current density quite low, about 30ma/cm2. Now Im thinking of two possibilities: platinum plated titanium from ebay, or commercial pool chlorinator electrodes. With the obviously large ammounts of experience of those on the forum, heres some questions:

producing perchlorate probably isnt too much of a big need for me, chlorate would be a good start, but:
Can platinum be run all the way from chloride to perchlorate? From what I have read, the intermediate chlorate is too insoluble in chloride solutions to be able to form perchlorate like this?

Are commercial pool chlorinator electrodes suitable for chlorate production? I understand that they are ususally MMO, which cannot be used for perchlorate?

Which, if either, would be my best option? Power supplies arent a problem, I have plently, and could build one in anycase if i were desperate.

I have heard of people using platinum wire, and it corroding badly, and others using platinum with no noticable corrosion.

I still have plenty of graphite, but the fine particles are a pain to filter.

Cheers,
Jesse
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hissingnoise
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[*] posted on 8-1-2010 at 04:37


Hi Jesse. If money isn't an object, you could splash out on two polished platinum foil electrodes.
The Pt lost from the anode should plate onto the cathode and periodically switching polarity might keep both electrodes in pristine, polished condition.
And with that set-up, chloride to perchlorate would be a breeze. . .
As for graphite, not all gouging are created equal.

[Edited on 8-1-2010 by hissingnoise]
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[*] posted on 8-1-2010 at 05:21


People that using pool chlorination electrodes say these work quite well.
If you would like to keep budget low one could go for used ones.
these things have relative low current density but are often quite large so one could pump some amps.

As you could have guesses .. there is already a topic about this.
To keep things organized it might be useful to continue further discussion there.

Btw check out the website of W. visser you will be amazed, that is if you didnt know it yet.




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[*] posted on 9-1-2010 at 17:14


frosty90

I'm afraid various members of this forum are becoming fatigued answering the same old chlorate/perchlorate questions over and over again! Your poorly worded post hasn't helped either, hence the few replies! There are literally dozens and dozens of posts on this forum dealing with chlorate/perchlorate/anodes etc. All of your questions have been answered before.

Have you visited dann2's site: http://www.oxidizing.110mb.com/

You do not mention what the capacity of your NaClO3 cell was, did you start with a saturated NaCl solution, and you ran it for (how many?) weeks. Did you do any basic run-time calculations.

10A for, say, 2 weeks, thats 14 x 24 x 10 = 3360 Amp hours

160.8 Ah are required to convert 1 mole NaCl (58.5g) to 1 mole NaClO3 (106.4g) at 100% efficiency.

So, at say 25% efficiency (very sad figure indeed) 3360 Ah will make 5.22 moles (555g) of NaClO3. That's a lot of NaClO3 but easily soluble in a litre of water at 20 oC. I find it hard to believe that you were not able to recover much NaClO3 from your cell, after putting all that electricity through it. It is almost impossible to get "bugger all" product. I have run cells in peanut butter jars with battery carbons and got reasonable amounts of NaClO3. Sure, the graphite mess is a problem, filter it or let it settle. With a NaClO3 cell you will need to concentrate your liquor by boiling, reduce the volume by say a quarter or until crystals form on the surface (saturated). Then allow to slowly cool (insulate) large crystals will form, after separating them, you may be able to repeat the concentration/crystallisation step once or twice more (for diminishing returns).

For chlorate production, either obtain MMO mesh and Ti strap and spot weld your own anodes or get ready made MMO anodes from pyro sites. New MMO chlorinator electrode assemblies would be an expensive and unnecessary route to take. If you can obtain used chlorinator electrodes, they are suitable for chlorate production (assuming the MMO is not completely worn away).

Pt or platinised titanium electrodes can be used for chlorate but are not really suited for chlorine rich environments (ie. early stages of chlorate cell). The Pt coating of a platinised electrode is only a few microns thick and will be quickly destroyed in a chlorate cell. Save these electrodes for just making perchlorate from PURIFIED chlorate.

You will also need to convert the NaClO3 or NaClO4 to the potassium salts using KCl metathesis if you want to play with pyrotechnics.

Making KClO3 directly from KCl with an MMO electrode is a very elegant route to take. This is largely because the cell can be operated on an essentially continuous basis. KClO3 will crystallise out as it is fairly insoluble and can be scooped out from time to time as it forms and more KCl solution added.

There is no particular reason to go directly from NaCl --> NaClO3 --> NaClO4. Much better to purify your products and use the appropriate anode for each. Having said that, I am currently running an experimental cell doing exactly that, using MnO2 electrodes.

You say you have plenty of graphite, if it is in the form of large electrodes, make a 10 litre "paint bucket" cell. This will hold say 3.5Kg of NaCl which will theoretically convert to about 6.3 Kg of NaClO3 if run to completion.

[Edited on 10-1-2010 by Xenoid]
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[*] posted on 9-1-2010 at 22:24


Quote: Originally posted by frosty90  


I would like to build a cell for produceing potassium per/chloratem, and Im willing to spend a bit of money.

How much is the bit!!
It's a mile and a bit to Alice Springs. This is a true statement no matter where on the globe you are standing.

You can greatly decrease the erosion of Graphite if you add acid to your cell as you go along and (if using Na salt) stop the cell when Chloride concentration starts to approach 50 grams per liter.
Go to TechnoChem. section.
Swede has also a large quantity of info. at www.apcforum.net (and on this board too).
Dann2

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frosty90
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[*] posted on 10-1-2010 at 17:55


Hi,


Quote:

I'm afraid various members of this forum are becoming fatigued answering the same old chlorate/perchlorate questions over and over again! Your poorly worded post hasn't helped either, hence the few replies! There are literally dozens and dozens of posts on this forum dealing with chlorate/perchlorate/anodes etc. All of your questions have been answered before.


I am aware that you would get many of the same questions over and over. But there is a reason: there is a hell of alot of info out there, but its always scattered over pages and pages of rambling forum posts, with dead links etc. It is difficult for some one to start, because while everone else has been there before, theres never any 'conclusive' writeups on forums! Its all just scattered posts of 'i tried this, i built this, this happend'. Not to mention I havnt been able to dig up the site by dann2 for about a year, (yes I have read it); all links I could find to it were dead, but now youve given me a good link, thank you. I dont want you to do the work for me I just want a nudge in the right direction. Please hear me out:


The reson Im asking questions is that sure theres plently of documented info on the use of all the differnt anode materials, etc. but its very hard for one to decide which way to go! I merely wanted an opinion of what, given my circumstances would be best! I dont want to sound rude... but heres my simple questions:

Assuming K chloride is the starting material, can platinum (wire, plated titanium etc), be run succesfully from chloride to perchlorate, with little errosion, or is the (in)solubility of K chlorate going to be a problem (chlorate level in the solution will be fairly low, leading to errosion)?


You are right, chlorinator electrodes are quite expensive. Heres what Im thinking: If platinum cannot be run from chlorite to perchlorate, I would run a cell with graphite to produce chlorate, and produce perchlorate from the clorate in a cell using platinum. Does this sound reasonable?

Jesse

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watson.fawkes
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[*] posted on 10-1-2010 at 19:43


Quote: Originally posted by frosty90  
The reson Im asking questions is that sure theres plently of documented info on the use of all the differnt anode materials, etc. but its very hard for one to decide which way to go!
To get a useful answer for you, please answer two questions: (1) How much chlorate do you want to produce? This informs fixed costs vs. variable cost issues, efficiency, etc. (2) What's your personal time vs. money trade-off like? There are lots of ways to go, and different people, with different goals and capacities, may each rationally choose different ways of accomplishing their goals.
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[*] posted on 10-1-2010 at 20:46


frosty90

As watson says, you're not giving us much information to work with!

For example, is your "graphite" genuine graphite electrode material or nasty carbon gouging rods. How much money do you want to spend.

If you just want to make a few home fireworks/explosives there is probably no need to even make perchlorate!

I think you should just concentrate on making NaClO3 with graphite/gouging rods (cheap, dirty) or with MMO mesh that you can buy on e-bay or MMO electrode from a pyro site (more expensive, clean).

You will need to practice your recrystallisation techniques and your KCl metathesis reaction because even for simple home fireworks you really need KClO3 not NaClO3 (it is too hygroscopic) although fun can be had with it!
The electrical side of running a chlorate cell is only half the equation - the other part is actually extracting the chlorate in the form of nice clean crystals. As you appear to have already found out, this is not as straight forward as it sounds. A lot of people seem to fail in this aspect of the process!

This is where the advantage of MMO comes in, you can get nice, clean KClO3 directly, in one step from KCl, if you so desire (though less efficiently).

Once you have mastered making chlorate, then you can lash out and buy some platinised titanium mesh from an electroplating supplier or say De Nora (although their minimum purchase is about $250 from memory). With the platinised Ti electrode you will be able to make NaClO4 very easily from your bulk supply of nicely purified and recrystallised NaClO3 with few worries about erosion, it will last a long time (though don't ask me to quote numbers). ;)

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[*] posted on 11-1-2010 at 03:10


Hi,

My graphite is 'EDM machine' electrode graphite. Quite hard stuff, (although I'm no connoisseur of graphite) rectangular sheets about 65 x 130 mm by 6mm thick. I have plety of pieces (more than 50).

Quote:
"How much chlorate do you want to produce"


Maybe a few hundred grams per week. Obviously more is better (isnt it always?) but I could never use more than about 500g in a week, with much effort. But this may change.

Quote:
"(2) What's your personal time vs. money trade-off like"


I'd rather wait a bit longer than spend lots!

The reason I mention perchlorate is that the general concensus among pyros is that its safer to work with than chlorate. I am not overly concerned with it for now however. The only reason I bought it up was if there was an anode that could be run from chloride through to perchlorate, I would probably try to get it.

Quote:
I think you should just concentrate on making NaClO3 with graphite/gouging rods (cheap, dirty) or with MMO mesh that you can buy on e-bay or MMO electrode from a pyro site (more expensive, clean).


I already have KCl; could I not simply run a graphite anode cell with this, rather than bother converting to the K salt from the Na salt? For, say, between 1 and 2 litres of cell liquor, is more effort involved in dissolving the KClO3 to filter the graphite, as opposed to starting with Na and removing the graphite mud then converting to K?

The problem I was having with my original attempts was when re-crystalising the NaClO3, I was getting alot of chloride with it too. I did make an aproximate calculation for runtime (leaving about 100g/L of chloride at the end of the run). I took a guess of 50% current efficiency when making my calculation, but it must have been much lower than that to have so much chloride come out of solution too (chloride started crystalising when boiling the cell liquor, when I noticed this I decided to stop boiling and cool it to crystalise the chlorate. But even with cooling, not much chlorate came out, and more chloride came out...). So what is a reasonable guess at current efficiency for a non pH controlled cell, running graphite (with KCl?) anodes, at about 40 to 50 degrees C?

Cheers,
Jesse

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[*] posted on 11-1-2010 at 03:40


Youre again asking to be spoonfed.

Why would you want to recrystallize NaClO3 , this seems very unnecessary to me.




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[*] posted on 11-1-2010 at 08:30


I never had a problem recrystallizing NaClO3. NaCl doesn't precipitate, its solubility is independent of temperature. It does reduce the solubility of NaClO3 markedly though.

Tim




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Xenoid
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[*] posted on 11-1-2010 at 12:02


frosty90

Quote:
Why would you want to recrystallize NaClO3 , this seems very unnecessary to me.


Yes, well that's the point isn't it! Everyone does things differently and every cell is different depending on your circumstances and resources! :)

Quote:
rectangular sheets about 65 x 130 mm by 6mm thick


Well these are not an ideal shape (too short) but certainly not impossible to work with. Long rod shapes are easier, gouging rods from a welding shop would be cheaper and easier to build into a working cell. Your electrodes could probably be better utilised in a multi-electrode bipolar cell and run at a higher voltage, this would require fewer connections. But that's another story!

Quote:
Maybe a few hundred grams per week.


Are you planning on putting on a pyrotechnics display every night!

Quote:
if there was an anode that could be run from chloride through to perchlorate, I would probably try to get it.


Well, as far as I am concerned this is a bit of a myth, whilst being true in theory, it is just not really practicable. Concentrate on making chlorate. Walk before you can run!

Quote:
could I not simply run a graphite anode cell with this, rather than bother converting to the K salt from the Na salt? For, say, between 1 and 2 litres of cell liquor, is more effort involved in dissolving the KClO3 to filter the graphite, as opposed to starting with Na and removing the graphite mud then converting to K?


Yes, but it is even more inefficient and messy. I'll have to admit though, that I have never tried it. Just going on what I have read.

If you are boiling down your liquor and if you have a considerable amount of NaCl left, it will precipitate out as a sludge as the VOLUME is reduced. It can be filtered off with kitchen paper, and recycled. BTW always recycle your old liquors.
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[*] posted on 11-1-2010 at 13:16


Yes NaCl is the right salt for electrolysis and the widely different solubilities of NaCl and NaClO3 must be taken into account.
The limited solubility of NaCl changes little with temperature but NaClO3 is quite soluble in cold water and is extremely soluble in hot water.
It takes some considerable time to saturate the cell-liquor with NaClO3 and during this time enough NaCl needs to be added to convert first to hypochlorite and thereafter to chlorate.
This disproportionation proceeds quickly at high temperatures.
Bright light can decompose hypochlorite to NaCl and O2 as it forms and some transition metals can also cause this kind of decomposition.
It's worth remembering that water @ 0*C will dissolve ~820 gm NaClO3 per litre.

[edit]
Of course these are things you probably already know but restating the obvious can't hurt.


[Edited on 11-1-2010 by hissingnoise]
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[*] posted on 13-1-2010 at 07:45


How much chlorate do you want to produce?
Quote: Originally posted by frosty90  
Maybe a few hundred grams per week. Obviously more is better (isnt it always?) but I could never use more than about 500g in a week, with much effort. But this may change.
Let's start there. You're getting accused of asking to be spoon-fed, so here's an exercise for you to work out. What size power supply do you need to get that production rate? There are some assumptions you'll have to make about current efficiency, cell complexity, monitored vs. unmonitored operation, your weekly campaign schedule (when you start/stop/harvest), how much time you'll spend on production personally. You can reasonably assume that you'll have a mother liquor that you'll reuse from week to week, so do the steady-state estimate (rather than the start-up one).

I'd ask that you post how you do your estimate for others to read. You're not the only one facing a welter of possibility and a lack of experience sorting through it all; it will be useful of other people to read about your case.
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[*] posted on 16-1-2010 at 16:50
Reading Material


Chlorates and Perchlorates.rar (15.5 MB) contains the following Files:

1. - Lead Dioxide Anodes - HTML

2. - US Patent 5.104.499 - Electrolytic Production of Alkali Metal Chlorates and Perchlorates.pdf

3. - Chlorates and Perchlorates.pdf

4. - An Idiots Guide to Making Chlorate's and Perchlorate's - By WarezWally.pdf

5. - A Study of the Production of Sodium Perchlorate Electrolytically - By Frederic A. Maurer (Thesis - California Institute of Technology - 1923) 33s.pdf



6. - Materials Handbook - A Concise Desktop Reference - 2nd Edition - By Fran├žois Cardarelli (Springer-Verlag - 2008) 1365s - Including Bookmarks

* Lead Dioxide (PbO2) Electrodes; Starting at Scan Page 606 with Preparation and References on Scan Page 607

iFile.it Download Link:

http://ifile.it/35xrnhz

No Password Required !

Enjoy !

Lambda
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[*] posted on 2-2-2010 at 21:09


I'm just curious, by if I were to make a small pilot cell, maybe no bigger than 100ml, would the Iodine in Iodized table salt cause any problems with the reaction? I ask because I do not recall seeing this addressed anywhere else.
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[*] posted on 2-2-2010 at 21:59


@wolfman, welcome to Sciencemadness,

Salt for human consumption is produced in different forms: unrefined salt (such as sea salt), refined salt (table salt), and iodized salt. It is a crystalline solid, white, pale pink or light gray in color, normally obtained from sea water or rock deposits. Edible rock salts may be slightly grayish in color because of mineral content. Additional contaminants would be substances added to make the salt Free-Flowing.

It will be best to use refined salt (table salt), and Iodine would in my opinion not interfere with the the Electro Chemically Chlorate/Perchlorate production. It will not "Poison" the electrodes used in the Chlorate/Perchlorate Cell.

Lambda
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[*] posted on 2-2-2010 at 22:01


Cool, thanks Lambda. I wasn't sure, and I am trying to learn as much about Chlorate/Perchlorate production as I can before I attempt to manufacture them. I was mostly worried about the trace amount of Iodine forming a potentially dangerous, explosive substance in the solution and causing an unexpected explosion.
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[*] posted on 2-2-2010 at 22:22


@Wolfman,

Iodine will probably give small amounts of Iodates/Periodates, but nothing to worry about. Iodine with Ammonia would be a completely different story though, but this is irrelevant to the Chlorate/Perchlorate Production.

Here you have an excellent Website by our member @Dann2:

The Chlorates and Perchlorates:

http://www.oxidizing.110mb.com/

And discussions concerning Electrodes for Chlorate/Perchlorate Production on this Board you can find here:

Thoughts On Anodes:

https://www.sciencemadness.org/whisper/viewthread.php?tid=50...

Lambda
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[*] posted on 2-2-2010 at 22:27


Thanks again Lambda. The Iodates might cause some interesting effects in pyrotechnic compositions.
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