Gaudin Lecture - Sulfide And Metal Leaching Reactions

"For his creative efforts in explaining the electrochemistry of sulfide mineral leaching systems." Leaching reactions that occur during the dissolution of selected base metal sulfides and metals are considered in terms of surface reactions and the influence of intermediate or final products formed. These products may be solid layers, requiring solid phase diffusion for the reaction to proceed, or ions in solution that can influence the kinetics by controlling the mixed potential of the solid. Three general types of reactions are proposed to explain observed rates of reaction. Examples are presented for non-oxidative and oxidative leaching of galena (PbS), anodic dissolution and oxidative leaching of molybdenite (MoS2) and cyanidation of silver and gold.