Recovering of Ni, Co and Cu from Divrigi Iron Plant tailings by sulphuric acid oxygen pressure leaching
Turkish Iron and Steel Company at its Divrigi concentrator plant produces magnetite concentrate for sintering using dry and wet magnetic separation. Nearly 750.000 tons of tailings are sent to tailings dam from Divrigi concentrator every year. These tailings contain 0.11 % Cu, 0.145 % Co, 0.35 % Ni, 0.25 g/t Au and 2.2 g/t Ag. The mineralogical composition of these tailings is complex and the minerals of the important metals are present as oxide and sulphides showing fine-grained structure. In this study, the recovery of these metals as Cu, Co and Ni was investigated, using oxidative sulphuric acid pressure leaching. The investigated parameters were leaching time (1 to 8 h), leaching pH (0.5 to 2), leaching temperature (110 °C to 180 °C) and partial oxygen pressure (1 to 6 bar). Under the optimum experimental conditions that were 4 h of leaching, 0.5 pH, temperature of 110 °C and oxygen pressure of 4 bar, the obtained recoveries were 64.10% Ni, 65.01% Co and 76.40% Cu.