AN ELECTROCHEMICAL STUDY ON THE DISSOLUTION OF GOLD AND COPPER FROM GOLD COPPER-ALLOYS

The dissolution behavior of gold and copper from their elemental state s and from gold/copper alloys in cyanide solutions has been investigat ed using a rotating-disc electrode. The anodic and cathodic reactions were studied separately, and the resulting polarization curves were co mbined to examine the overall dissolution reactions. The dissolution r ate of pure gold in the aerated cyanide solutions was inhibited by the anodic passivation on the gold surface,;whereas the dissolution rate of pure copper was found to be mass-transfer controlled. On the other hand, the dissolution of gold and copper from the alloys was partially controlled by electrochemical reaction and largely by mass transfer.