NaK
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Recycling chromium sulfate from alcohol oxidation
Is there a good way of recycling the chromium sulfate waste from a potassium dichromate oxidation reaction to chromic oxide again? Considering
chromium being somewhat expensive I would like to reuse it and oxidize it to dichromate again.
Converting it to CrOH and performing a thermite like reaction then comes to mind but that would not be very efficient and would also lead to metallic
chromium which would have to be oxidised again.
Is there a better way to achieve this?
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Amos
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You can simply take the aqueous waste, assuming all of it has been reduced to chromium(III) and treat it with sodium carbonate solution to precipitate
the hydroxide, and I've found this precipitate is more granular/easy to filter than the precipitate formed with the addition of sodium hydroxide. If
you heated your mixture significantly during the oxidation you might get a messier result; some chromium won't precipitate and that which does will be
more green and sticky. Regardless, these precipitates will readily dissolve in hot hypochlorite to give a pure yellow solution of chromate, which is
easy enough to refine into potassium dichromate.
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draculic acid69
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Thermite with chrome sounds like a really bad idea.
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NaK
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Quote: Originally posted by Amos  | | You can simply take the aqueous waste, assuming all of it has been reduced to chromium(III) and treat it with sodium carbonate solution to precipitate
the hydroxide, and I've found this precipitate is more granular/easy to filter than the precipitate formed with the addition of sodium hydroxide. If
you heated your mixture significantly during the oxidation you might get a messier result; some chromium won't precipitate and that which does will be
more green and sticky. Regardless, these precipitates will readily dissolve in hot hypochlorite to give a pure yellow solution of chromate, which is
easy enough to refine into potassium dichromate. |
great idea, I completely ignored that possibility
I think so too
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