Sulfuric acid leaching of copper and lead from gold-bearing cathode deposits

Abstract

The purpose of the paper is to study the chemical composition of cathode deposits obtained at gold-bearing ore processing by the cyanide-sorption technology; to conduct experimental studies of the sulfuric acid leaching of copper and lead from gold-bearing cathode deposits; to consider the effect of sulfuric acid concentration on the transition degree of copper and lead into solution. Mathematical processing of experimental data is performed by the correlation method. Chemical composition of the cathode deposits is studied by the atomic absorption analysis and X-ray spectral microanalysis. Having studied the chemical composition of the cathode deposits the main impurities influencing their further refining is identified. They are copper and lead, which should be removed before the following production of base gold bullion. The results of the experimental studies on sulfuric acid treatment of cathode deposits are as follows: the transition degree of copper into solution is 45.98%, lead - 3.65%, the optimal concentration of sulfuric acid is 165.4 kg/m³. The results of sulfuric acid leaching of impurities from the cathode deposits appears to be of low efficiency as lead can not be extracted into the solution due to the passivation of its surface with PbSO₄ film. The mathematical processing of experimental data by the correlation analysis has showed that the concentration of sulfuric acid affects the degree of copper and lead transition into the solution.