Pyrometallurgical reduction of Miller chlorides with iron

Mixtures of silver chloride and copper chloride are produced during gold refining by the Miller process. A study was carried out into the reduction with iron of a synthetic Miller chloride containing 13.64 mass% Ag and 2.42 mass% Cu. The effects of smelting temperature and time and of additions of iron and borax were investigated. The results were interpreted in terms of metal recovery and quality. Temperature did not have a significant effect on metal recovery above the melting point of the metal product. Borax additions reduced vapour losses and improved metal recovery. With excess iron it was possible to achieve silver recoveries of about 100% and copper recoveries of about 70%. The metal product contained on average 76.1 mass% Ag, 7.5 mass% Cu and 12.8 mass% Fe.