A Study of Anodic Dissolution of Gold in Aqueous Alkaline Cyanide

Abstract

The rate of dissolution of Au in aqueous alkaline cyanide solutions was studied as a function of potential within the range 0.9 to +0.4V vs. SCE. The dissolution rate was found to exhibit three max. at --0.65, +0.04 +0.38V vs. SCE. These max. corresponded to three current peaks found anodic potential sweep measurements. The dependence of the dissolution rate the concentration of KOH and KCN was determined in the two more anodic regions. At +0.38V vs. SCE the dissolution was directly proportional the cyanide concentration and independent of hydroxide concentration. At +0.04V vs. SCE the dissolution rate was approx. linear with cyanide low concentrations ( < 0.1M) and decreased with increased hydroxide concentration. At moderate hydroxide concentrations (0.1M) the dissolution rate decreased for cyanide concentrations greater than 23 refs.--AA