Pressure sulpuric acid leaching of a sulphide concentrate to recover copper, nickel and cobalt

摘要

The Jaduguda sulphide concentrate can be processed conveniently by a pressure leaching approach. Sulphuric acid leaching of the metals is accompanied by the formation of elemental sulphur that can be recovered as a by-product. The following conclusions were drawn from this investigation.(1) Recovery of the valuable metals-copper, nickel and cobalt-generally increased with increase in temperature from 373 to 418K and pressure from 1085 to 5195 kPa. The increase in cobalt recovery beyond 2170 kPa pressure was less pronounced than that of copper and nickel (at 373K).(2) Leaching of the three metals was quite satisfactory in the presence of 20 g/l acid at a solid: liquid ratio of 1:5 (g/cm~2) at 403K. With an increased acid content of 30 g/l sulphuric acid only the cobalt recovery was improved and the iron dissolution also increased (43 percent).(3) With a two-stage leach at a temperature of 418K under lower pressure in the first stage and higher pressure in the second the recovery of metals obtained was 79 percent Cu, 78 percent Ni and 95 percent Co. If the second-stage leach was carried out at lower temperature (373K), a high copper dissolution (89 percent) was observed with lower nickel (68 percent) and cobalt (57 percent) recoveries.