Noranda Inc.

Viken P Baboudjian

Jack S Stafiej

Bernard H Morrison

The present invention is concerned with a process for selectively removing antimony, bismuth, or both, from acidic solution by submitting the solution to oxidizing conditions thereby causing the selective precipitation of antimony and bismuth; filtering precipitated antimony and bismuth; and submitting the oxidized solution to reducing conditions before it is returned to the electrorefining cell.

Selective bismuth and antimony removal from copper electrolyte

A two-stage process for treating anode slimes and other residues containing a substantial amount of nickel without significant dissolution of silver and/or selenium in a single autoclave is disclosed. The process comprises, in a first stage, leaching the anode slimes at 15-30% solids in dilute sulphuric acid at a pressure between 4.0 and 5.5 bars and a temperature between 155.degree. C. to 170.degree. C. in the absence of oxygen to solubilize nickel, and in a second stage, without performing a solid liquid separation, leaching the remaining solids at a pressure between 2 and 3.5, preferably about 2.8 bars and a temperature between 110.degree. and 140.degree. C., preferably about 120.degree. C. with oxygen sparging such that the final sulphuric acid concentration is not less than 50 gpl to solubilize copper and tellurium.

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Pointe-Claire, Canada

Viken P Baboudjian