Behavior of S 2O 32− and SO 32− in sulfur-bearing aqueous solution system for gold leaching

Abstract

The concentrations of S 2O 3 2− and SO 3 2− were measured in gold leaching systems, including thiosulfate system, polysulfide system and the modified lime sulfur synthetic solution (ML) system in the process of chemical reaction. The interactions among S 2O 3 2−, SO 3 2− and S 2− were discussed. The behavior mechanism of sulfur-bearing reagents was proposed to describe the process reactions and their Gibbs free energy. The proper quantity oxygen and SO 3 2− reduce decomposition of S 2O 3 2− and react with sulfur derived from the decomposition of S X 2−. So, SO 3 2− ions have action to stabilize sulfur-bearing system and are favorable to leach gold.