INFLUENCE OF GOLD CONTENT ON COPPER OXIDATION FROM SILVER-GOLD-COPPERALLOYS

In the final stages of the smelting of copper anode slimes, a silver a lloy, known as ''dore,'' is produced. Oxidation refining is used to re move copper since this element interferes with subsequent electroparti ng of the small amounts of gold and platinum group metals in the dore. The gold content of dore can be greatly increased by gold scrap addit ions and this may affect the minimum achievable copper content of dore . In this work, silver-gold-copper alloys were oxidized by injecting p ure oxygen at 1100 degrees C in the absence of any slag covert. For th e gold contents expected in practice, the equilibrium copper content o f the dore did not increase significantly as the gold content increase d. However, at the other extreme of composition, the equilibrium coppe r content was a very strong function of the silver content of the gold bullion. The activity coefficient of copper in silver-gold alloys was calculated and compared to those predicted from a ternary subregular solution model of the system Ag-Au-Cu. Satisfactory agreement was foun d.