DFliyerz
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Potassium Chlorate without Heat
For about the past week, I've been running an electrolysis cell with 50g of potassium chloride dissolved in about 800ml of distilled water, running on
a converted wall power brick that can reach a maximum of 2 amps DC. The anode is MMO with a little bit of damage due to running previous batches at
excessive voltages when my good power supply wasn't acting up, and the cathode is graphite because I don't have any stainless steel that I can use at
the moment. Additionally, I have an acrylic lid with a curved gas outlet tube to reduce water loss due to evaporation. Anyways, here's the odd thing;
despite my cell never getting more than a degree or two above the fairly chilly room temperature of my garage, after about a week I started getting
what appears to be potassium chlorate crystals forming. And not just any old single flakes of potassium chlorate, I'm talking large chunks of flaky
crystals. So, how did this happen with out the heat normally required to generate potassium chlorate in situ in an electrolysis cell?
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Varmint
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you are taking the 9 electron route. But before any serious discussion can begin, you are running a VERY low chloride concentration, so I would up
that before I ran it again.
At room temp you can get 350G KCl per liter of distilled water, and you won't be starved for chloride after a 5A run for a week.
If you want to run a cell and harvest cold, there is no harm, but if you want to get maximal yield, remove the electrodes and boil the liquor before
cooling. Nice thing is, if you let it cool slowly, you get nice big plates. I regularly get cm square cystals, one time I was able to achieve
several near postage stamp sized crystals, but that was with extreme effort in both filtering and temperature control.
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Zyklon-A
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Right you are Varmint, chloride electrolysis has many different factors. There's so many stages of oxidation you could fill a book
with nothing but possible equations. Point is, chlorate can form without heating, it's far less energy efficient but it can happen. When it does more
oxygen is released at the anode, which means the pH will go up. This happens especially is low chloride solution, so add more.
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DFliyerz
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I may just continue doing it the way I am, since I like being able to just leave the cell running and do other stuff. The yield is also good enough
for me, since I don't really use chlorate often.
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Zyklon-A
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I'd still add chloride though, I've heard it's bad for the MMO to run until the chloride is all gone.
Then again, I can always sell you another anode!
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Varmint
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Fine by me, but I strongly encourage you to up the chloride concentration. If you don't, and you forget to harvest and restock chloride on time you
run the danger of damaging your MMO from having too little!
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DFliyerz
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Quote: Originally posted by Zyklon-A  | I'd still add chloride though, I've heard it's bad for the MMO to run until the chloride is all gone.
Then again, I can always sell you another anode! |
Hehe, yeah. I ran it for far too long at far too high of a voltage last time, so it started wearing away and my adjustable power supply hasn't been
cooperating lately.
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Varmint
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Forgot to mention, the hypochlorite smell is real, but aquaeous only (there is no solid potassium hypochlorite.
So when you wash your crystals, you want to remove the chloride of course, but you cannot remove all the hypochlorite smell, it's is a VERY potent
odor, if you try to wash it clean, you'll have no crystals left.
This is where boiling comes in.
Not only are you thermally converting the hypochlorite into chlorate, but easing the washing. Still, you will have some left (hypo), but rest
assured, once dried to anyhydrous, the hypo smell disappears.
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