Process Oriented Characterisation of Copper Slag Processed by Flotation in View Metals Recovery

Profound process oriented characterisation on samples collected during plant survey of the slag flotation plant belonging to Aurubis AD, Bulgaria has been realized in order to evaluate the form under which Cu, Ni, Mo and Co bearing phases occurred and likewise their mineralogical composition. The slag subjected to flotation consisted in majority of fayalite, magnetite-iron oxides and a glass-resembling phase. Ni and Mo have been found to be closely associated to iron-bearing phases. The flotation tailings sample has been subjected to sulphation roasting followed by water leaching as a hydrometallurgical route to recover the remaining Cu, Mo, Ni and Co. Based on the various sulphation roasting process conditions (acid dosage, duration, temperature), copper, nickel and cobalt were brought in solution to a different extent. Sulphation roasting performed at 350 °C has secured the best extraction degree for Mo and Co, while maximum recovery of Ni and Cu has been documented when roasting was done at 150 °C and 450 °C respectively. EDS-SEM observations of various products do support the experimental findings.