A study of the chlorination of gold: The effect of nascent chlorine, mechanism determination, the role of sulfide minerals and carbon, and the effect of multivalent catonic chloride salts

Abstract

A three-phase study has been conducted to investigate the effect of chlorine on the dissolution of elemental gold. The study lead to a conclusion that the existence of a "nascent chlorine" atom was not responsible for an observed increase in recovery and gold dissolution rate when chlorine was chemically formed in situ. Instead, the chloride reagents added to produce chlorine--HCl, NaCl, etc.--increased the ionic strength of the solution which increased the dissolution rate of gold. Also, the study concluded that the reason why flash chlorination is a successful pretreatment for carbonaceous gold ores is due to the adsorption of dissolved metals from sulfide minerals on the surface of the carbon. The adsorption of iron and copper reduces the adsorption of Au.