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Picric-A
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Chlorate Cell with different electrolute
I dont have a cheap source of pure KCl but what i do have is a cheap source of 'dietary salt' wich is basically a mix of 60% KCl and 40% NaCl. Now,
both these salts have roughly the same solublilty so recrystalisation would do nothing.
Could i make a brine out of this salt mix and electrolize that and eventually get a 60% precipitate of KClO3?
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12AX7
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Sure, and then keep cooking it, then boil and add more KCl and cool to crystallize more KClO3, then cook some more, add more KCl, etc... Or don't,
and end up with some NaClO3 too.
Tim
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Picric-A
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Yes thats a good point, at one point all the KCl would be used up... If i were to add another potasssium salt, eg K2SO4 to the brine would that muck
it up?
I guess:
K2SO4 + 2H2O --> 2KOH + H2SO4
And the K2SO4 would be constantly regenerated until it was turned to KClO3 by the methasis reaction:
NaClO3 + K2SO4 --> KClO3 + Na2SO4 (unbalaced but hey!)
Would the H2SO4 generated destroy the graphite anode quickly and what % do i need to have the K2SO4 for it not to get in the way of the chlorate
making?
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watson.fawkes
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If you continue to add potassium sulfate, the concentration of sulfate will continue to rise. This is generic. If you add something extraneous, you
need a way of taking it out.
If you can get potassium sulfate, I should point out that calcium sulfate is not very soluble and that calcium chloride is easy to get.
I will also point out that there's a pretty good differential solubility between sodium and potassium oxalate.
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Picric-A
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how soluble is calcium chlorate? i cant find an msds for it.
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12AX7
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Very soluble.
Why would you add K2SO4? It's sparingly soluble as is (on par with KClO3), and as Watson states, you're left with sulfate. You're removing potassium
and chlorate as a product, so you must add potassium and chloride (being your substrate), preferrably as KCl, to keep it going.
KCl is cheap and readily available, so this isn't a problem.
Tim
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Picric-A
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| Quote: | Originally posted by 12AX7
KCl is cheap and readily available, so this isn't a problem.
Tim |
not trying to be aggressive but if you had read my first post i mention that i dont have a cheap, pure source of KCl.I am meerly finding out what
other salts can be used for the methasis reaction. will any salt of a more reactive metal (eg. potassium nitrate) discplace a salt of a less reactive
metal (eg- soidum permanganate) (so potassium nitrate + soidum permanganate--> potassium permanganate + soidum nitrate ???) am i right or saying
this or completly wrong
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watson.fawkes
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Here are some further hints related to my previous post.
If you mix potassium sulfate and calcium chloride, what happens?
By starting with a salt mixture, you've essentially added extraneous sodium. How could you use oxalate to take it out?
If you've got extraneous oxalate, how do you take it out? Perhaps there is an insoluble oxalate; see http://en.wikipedia.org/wiki/Solubility_table.
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Picric-A
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duh... CaSO4 ppt.
ppt out insouble oxalate salt- sodium oxalate- exremly limited solubility
calcium oxalate- practically insoluble
You dont need to treat me like a retard you know???? i just needed guidance
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watson.fawkes
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@Picric-A. OK. I did think you were being kind of dense about gypsum precipitate. You can just make potassium chloride solution and start
with that. No need for mixed salt in the first place in that case.
The oxalate issue is more subtle. Oxalic acid is available as a wood bleach. Here a US mail-order example. It's not very expensive, but it's not real cheap either. Sodium oxalate isn't exactly insoluble, about a tenth that of potassium
oxalate. Using it without recovery would get expensive. Think about a differential extraction between sodium and potassium, iterated and with oxalate
recovery.
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12AX7
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| Quote: | Originally posted by Picric-A
not trying to be aggressive but if you had read my first post i mention that i dont have a cheap, pure source of KCl. |
Oh duh, you had said that.
Well, then, how is it possible that you can't find KCl? Over here we have it sold in 50 pound (20 kilo  ) sacks for water softeners. It comes in salt mixtures for seasoning food ("low-sodium salt", if you can imagine such
a thing) and melting road ice.
Incidentially, isn't chlorate (usually of sodium I suppose) available over there too, or is (was?) that more of a continental thing?
| Quote: | | will any salt of a more reactive metal (eg. potassium nitrate) discplace a salt of a less reactive metal (eg- soidum permanganate) (so potassium
nitrate + soidum permanganate--> potassium permanganate + soidum nitrate ???) am i right or saying this or completly wrong |
No (although potassium permanganate will precipitate in this case). Reactivity has nothing to do with it, as both sodium and potassium go through the
process unchanged, always inert ions, in solution or in crystal. So what remains is solubility as the driving force for these reactions.
Tim
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Picric-A
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I do have acces to the low sodium salt however that is only 60% and like i said furthur up the thead their solubilitys are the same so seperation
would be almost impossible.
Potassium chlorate is not available here, only extremly expensivly from chemical suppliers (around £9/100g) and no we own a water sotener and have
asked loads of companys and non f them sell KCl as a sofening agent, only NaCl... wich is a pain.. 
Picric-A
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tentacles
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Have you tried finding potassium chloride as fertilizer? Try some hydroponics shops - though keep in mind that few will stock big bags of raw
fertilizer, you will have to ask them to look through a catalog and order it most likely. Ask for 0-0-49.8 fertilizer, potassium chloride, muriate of
potash. You might try a farm supplier or feed store as well.
I believe it's used particularly in growing potatoes, but it's a common fertilizer.
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ScienceSquirrel
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It is quite easy to fractionally crystallise potassium chloride from Lo Salt.
Potassium chloride is produced on an industrial scale by fractional crystallisation of mixtures of sodium and potassium chloride.
A few days work will yield a few hundred grams of potassium chloride from 1 kg of Lo Salt.
Objectively it is a waste of time and money but after several days of crystallisations you will have a really good technique 
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Picric-A
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Yes i live next to a farm and have even been reduced to asking that farmer if he knows where i can buy 'muriate of potash' for my 'tomotoes and
potatoes' lol
I guess o will have to try crystallisation.... aah long and boring procedure
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Contrabasso
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Unless someone knows better, I've found KCl to be available only as a High Grade lab supply at serious cost, here in the UK. I cannot find a "water
softener type" supplier selling multi kilo bags. I was planning to have a perc production set but having to fractionally crystalise the choiride first
doesn't make me happy
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watson.fawkes
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There's a chapter in the Handbook of Industrial Crystallization called "Crystallizer Selection and Design" that folks might want to look at. There are picture of several
different approaches that might inspire a low-volume and inexpensive version.
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dann2
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Hello,
As said by others, Muriate of Potash is a common as muck fertilizer sold in just about every farm store.
Stuff I seen says '50% K' (so it is not 100% pure KCl, if it were 100% it would be 52%)
One recrystallization will get you the stuff pure enough.
Do any of you guys know where an explanation (detailed talk-through as it were) of how to use/understand a mutual solubility graph can be had?
Searching for 'mutual' in the book above it seems to have data or a graph (not shown though, only heading on page gives indication of information) on
the mutual solubility of KCl and NaCl. Anyone here have this book?
Cheers.
Dann2
[Edited on 4-9-2008 by dann2]
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watson.fawkes
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Solubility products
| Quote: | Originally posted by dann2
Do any of you guys know where an explanation (detailed talk-through as it were) of how to use/understand a mutual solubility graph can be had?
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Start with looking for a treatment of "solubility products". It's not a perfect model, but it does
adequately treat the generic mutual solubility. After that you get to worry about non-generic solubility interactions, like complexing. Just to get
started, here the Wikipedia entry for Solubility equilibrium.
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watson.fawkes
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Solubilities of inorganic and organic substances, A handbook of the most reliable quantitative solubility determinations, by Atherton Seidell
This edition is from 1917; it's out of copyright. (Might I suggest adding it to the SM library?) Page 245 has a table on mutual solubility of
potassium and sodium chlorides at different temperatures.
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ScienceSquirrel
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Have you tried your local aquarium shop?
It is widely sold for boasting the potassium level in marine aquariums.
http://cgi.ebay.co.uk/MARINE-AQUARIUM-Potassium-Chloride-500...
The easiest way to make potassium chlorate at home in the UK is to mix a solution of Lo Salt with a solution of sodium chlorate purchased from your
local garden centre and cool the solution. The potassium chlorate crystallises out.
One recrystallisation and it is very pure indeed.
You should not make it on a big scale anyway as it is hazardous.
Cloth, paper etc that have absorbed the solution are extremely flammable when dry and mixtures with sulphur etc are not to be trusted and certainly
never stored!
[Edited on 5-9-2008 by ScienceSquirrel]
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Contrabasso
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If only I knew what the "fire depressant" in garden chlorate really was. But I do like the idea of the K salt ppting out cleanly.
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ScienceSquirrel
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| Quote: | Originally posted by Contrabasso
If only I knew what the "fire depressant" in garden chlorate really was. But I do like the idea of the K salt ppting out cleanly.
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If you read the manufacturers' stuff then it is not that hard to work out.
Really you can start from 100g of OTC 58% sodium chlorate and drop out 40g of 98+% potassium chlorate in a few hours.
But you need the gear, vacuum filtration, glass frits etc.
Any organic materials exposed to the chlorate solution should be thoroughly washed with water before being added to the normal household waste.
The residual solutions can be used as a weedkiller on paths etc.
[Edited on 5-9-2008 by ScienceSquirrel]
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kclo4
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I know you don't have a great potassium source, and this isn't really one, but I'd imagine if you wanted to you could try to purify Potash, probably
have a bunch of it from your wood burning fireplace.. assuming you have one..
I believe it is rather high in potassium, and a large portion of the impurities are not soluble.
You may be able to add the K2CO3 and precipitation the KClO3, but I don't know since I haven't looked at the solubility of Na/K Carbonates and such.
Ok, like I said, I know its not a good way to do it. Just thought I'd put it out there.
For solubility reasons, and perhaps stability of the hypochlorite formed, isn't it better to use NaCl for the conversion of Cl- into ClO3-? I
vaguely remember reading that somewhere, but again, you'd have to look into it more.
[Edited on 5-9-2008 by kclo4]
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watson.fawkes
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Found this reference in an endnote. Thought some folks might want to take a gander.
How to Design Fractional Crystallization Processes
Bryant Fitch
Industrial & Engineering Chemistry Vol. 62, No. 12: December 1970 pp 6 - 33
DOI: 10.1021/ie50732a004
http://pubs.acs.org/cgi-bin/archive.cgi/iechad/1970/62/i12/p...
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