Effect of Reductants on Valuable Metals Separation and Recovery from Copper Cliff Converter Slag

The aim of the project is to investigate new material as a reductant in nickel extraction and purification processes. The analyzed reductants were coke, pig iron, ferrosilicon and two copper-silicon alloys. The mixture with the slag and reductant was poured into a cylindrical alumina crucible and kept in a furnace for one hour at 1573 K (1300 degrees C). After settling, the solidified sample consisted of the matte settled at the bottom of the sample separated from the slag at the top. Ferrosilicon was found to be the most effective reductant for cobalt recovery while 70wt%Cu-30wt% Si alloy facilitated 72% copper and 87% nickel recovery. The highest copper recovery is achieved with 90wt%Cu-10wt% Si reductant. Due to low melting point, high exothermicity and suitable density, Cu-Si alloys could be an ideal choice for the pyrometallurgical converting processes.