Abstract:The dissolution kinetics of gold and silver cyanidation of Cu-Au sulFide concentrate has been investigated at ambient temperature in consideration of effects of various parameters, such as particle size of ores, hydrodynamics of the process and initial cyanide concentration as well as oxygen partial pressure. The experimental data are mathematically treated with an approach based on the shrinking core model. A phenomenological expression describing the rate and rate constants for cyanidation of the concentrate is developed from the treatment. The dissolution of gold and silver is explained by an electrochemical mechanism in which the rate determining step is the diffusion of cyanide and dissolved molecular oxygen through a porous layer formed during the minerals dissolutions

Key words: dissolution kinetics  Cu-Au sulfide concentrate   cyanidation  electrochemical mechanism