alter leaching from Li-Ion Bateries, Ive got a lot of Cobalt hydroxide (green precipitate that turn brown in a matter of minutes)
My idea was to obtain Cobalt Sulphate / Chloride, so I separated in 2 portions the hydroxide, and treated one part with 33% H2SO4 and the other with
20% HCl.
Filtered and obtained a similar color (brown - clear) in both solutions.
(Ive got already a solution of Cobalt Chlroride -(from metal cobalt disolving in HCl - which is dark green) and Cobalt sulphate (cobalt metal + H2SO4
- which is light red) - so no brown.
So probably my solution is heavily contaminated - first estimation is Iron - because of steel casing cutted by a Dremmel - When I pick up the magnetic
stirbar, some fillings where attached to it.)
So the questios:
1) is there a simple way of purifying the Cobalt sulphate/Chloride? (or hope for the best by cristalization)
2) is there a way to purify the cobalt hydroxide? (so I can in the future purify it before treating with acids)
Process for leaching Ion batteries includes: treating with NaOH to remove Aluminium, then HCl - to dissolve the metals- and finally NaOH, till green
precipitate was seen)
Thanks,DraconicAcid - 6-1-2023 at 10:08
If the brown is from iron, you can precipitate the iron with ammonia. Cobalt forms a complex with ammonia, and stays in solution, but iron will
precipitate as the hydroxide.clearly_not_atara - 6-1-2023 at 10:27
If you form the cobalt ammine complex, you can precipitate Co(NH3)6Br3 with high efficiency. You need to oxidise the Co(NH3)6(2+) to the (3+), though.
The complex itself is prepared by oxidizing cobalt in the presence of ammonia. The tricky part would be oxidizing the cobalt completely without also
oxidizing the bromide.
Add ammonium sulfate and ammonia to your cobalt solution, filter and treat with hydrogen peroxide, filter again, then destroy any remaining peroxide
with a little iodine. Then you should be able to add NaBr and get a nearly quantitative precipitate. Practically nothing else precipitates with
bromide, which is convenient.
[Edited on 6-1-2023 by clearly_not_atara]blogfast25 - 6-1-2023 at 14:07
(Ive got already a solution of Cobalt Chlroride -(from metal cobalt disolving in HCl - which is dark green) and Cobalt sulphate (cobalt metal + H2SO4
- which is light red) - so no brown.
