Hydrometallurgical processing of anode s

The anode slime obtained from Indian Copper Complex, Ghatsila was used for the recovery studies with the aim of developing a hydrometallurgical processing route. The chemical analysis of the slime showed that it contained valuable metals like copper, nickel, selenium, tellurium, gold, silver and platinum group metals. Characterisation study by XRD analysis revealed the presence of various phases like NiO, CuSO4.5H2O, NiSe, α-CuSe, Cu2SeTe, Cu2Te, (Cu0.2Ni0.8)O, Cu2Te, AgCu2Te,10 SiO2 etc. in the slime. Presence of free moisture, combined moisture, selenium and tellurium were detected by TG/DTA studies. Preliminary leaching experiments of the anode slime in sulphuric and hydrochloric acid media at different conditions were carried out to recover copper, nickel and tellurium. Maximum copper recovery in sulphuric acid and hydrochloric acid leaching experiments at normal pressure was found to be about 55% and 77% respectively. In both cases, nickel and tellurium recoveries were poor. In the autoclave leaching, copper and tellurium recoveries improved with increasing time and pressure. Maximum copper and tellurium recoveries to the tune of 85% and 71% respectively were achieved using 1% sulphuric acid as leachant. On increasing the sulphuric acid concentration to 20% in the pressure leaching, the recoveries of copper and nickel improved to 95% and 46% respectively.