Recovery of Metals from Nickel Laterite Leach Waste Using Chelating Resin

摘要

Nickel reserves are 70 % from laterite ores and nickel production are 40 % from these reserves. It occurs due to the fact that laterites ores require more complex processing than sulfides. For this reason, innovations must be developed to overcome it. The main problem of nickel limonite is high concentration of iron, which decrease metals recovery hydrometallurgical process efficiency. Ion exchange process can be used to recover valuable metals from leach solution, such as nickel, cobalt and copper, but at pH above 2 iron precipitates with copper and cobalt. The aim of this work was to study the copper recovery using chelating resin selective for copper. Reducing process using sodium dithionite 1 mol.L-1 was used to reduce the potential of solution, converting Fe(III) to Fe(II) and work at pH above 2, without iron precipitation. Results shows that copper recovery increases in presence of sodium dithionite. At pH 2.50 copper recovery was 71.18 % in batch experiments, and at pH 3.00 and 3.50 selectivity order of resin has been changed, being more selective for nickel and zinc than copper. At pH 3.00, metals recovery was 19.55 % for copper, 21.91 % for nickel and 24.04 % for zinc, and at pH 3.50 copper recovery was 8.95 %, 25.20 % for nickel and 21.25 % for zinc. Therefore, metals recovery efficiency increases using chelating resins allied with reducing process comparing without reducing process.