Numerical simulation of copper recovery from converter slags by the utilisation of spent potlining (SPL) from aluminium electrolytic cells

An innovative method was devised to improve copper recovery and operational efficiency of the Cu converter slag-cleaning furnace, by utilising both carbon and fluoride values of an otherwise environmental hazardous material (i.e. spent potlining (SPL)) produced from the aluminium industry. Results based on numerical modelling show that 90% Cu recovery could be achieved by adding as little as 3-4 wt-% of SPL to the molten converter slag. The fluorides and sodium-containing compounds in the SPL reduced the slag viscosity, resulting in a much faster settling rate of matte droplets. In this process, the SPL could be detoxified by destroying the cyanides to form harmless N-2 gas, and inertising the fluorides in a much diluted form in the ferro-silicate slag, ensuring a safe disposal to the environment.