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.

Graphical AbstractFigure optionsDownload as PowerPoint slideResearch Highlights
► Hydration number and water residence time were calculated for cyanoanions by MDS.
► Hydration state of cyanoanions is mainly affected by charge and number of ligands.
► Weakly hydrated cyanoanions have a tendency to aggregate and form clusters.
► Aurocyanide anions have a lower hydration state in comparison to other cyanoanions.
► Findings may contribute to the fundamental understanding of gold hydrometallurgy.