Molecular dynamics simulations of metal-cyanide complexes: fundamental considerations in gold hydrometallurgy

This study utilizes molecular dynamics simulations (MDS) in order to evaluate the hydration state and the characteristics of metal-cyanide anions in aqueous solutions. Cyanide complexes of gold, silver, zinc, mercury, and copper were examined. Tetracyano anions of zinc and mercury showed the highest level of hydration, whereas dicyano anions of mercury, gold, and silver showed the lowest level of hydration. Several of the cyano anions were found to form clusters in solution. Other species, especially the tetracyano complexes, were found to be well dispersed in water. This MDS information on the behavior of metal-cyanide complex anions may lead to further advances in the understanding of processes being used in gold hydrometallurgy operations. This paper discusses the results from simulations and how these results contribute to a fundamental understanding of carbon adsorption, solvent extraction/ion exchange, and membrane water treatment processes.