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Electrowinning Problems

I am involved in a small tailing reclamation project in Mexico, that uses bromine chemistry to leaching and RIP recovery. The resin is eluted using two different chemistry: (1) bromine-HCl and (2)Thiourea-HCL.

We have been attempting to electrowin the pregnant eluate with concentration of Au, Ag, and PGMs with very little deposition on the cathode. Our electrodes consist of a flat-sheet electrolytic carbon (anode) and stainless steel cathode. We are having a very minimal deposition of metallics on the cathode, even though assay shows that substantial values exist in the electrolyte.

Any helpful suggestions would be greatly appreciated.

Kenneth Christos
Project Manager - Nogales, Arizona, USA
2003

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Unfortunately, solutions that are good for leaching metals are usually too aggressive for electrowinning. Even if the metals are deposited on the cathode, they are instantly re-dissolved. The solution to this problem is to change the chemistry in some way to make the electrolyte less aggressive. This may require a pH change, and/or destruction of the oxidizer that is present.

Lyle Kirman
consultant - Cleveland Heights, Ohio
2004

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Lyle Kirman,

Thanks for your comments to our inquiry regarding problems with electrowinning. Can you, please, suggest how to destroy the oxidizer that is present in the electrolyte. Thanks for your response.

Kenneth Christos
- Nogales, Arizona
2004