PROCESSING OF PYRITE CONCENTRATES WITH THE EXTRACTION OF NONFERROUS METALS: NICKEL AND COBALT TECHNOLOGY ELABORATION

The paper presents the results of the development of a technology for processing of pyrite concentrates with the extraction of nonferrous metals, iron and sulphur using the technology of two-stage dissociating roasting with hydrometallurgical processing of cinder. Hydrometallurgical processing of cinder was studied. It comprised of two steps - cinder leaching and extraction for processing multi-component solutions. Based on the results of laboratory tests, balance experiments were conducted on the chemical enrichment of nickel-poor and cobaltpyrite concentrates. The experiments included (i) Thermal decomposition of pyrite concentrate at a temperature of 660 - 700° C and a duration of 60 minutes, an oxygen flow rate of 30-50% of the stoichiometric; (ii) Leaching of the cinder with a HCl solution at a temperature of 90°C, liquid: solid = 8:1, pH 2,7 and a duration of 60 minutes; (iii) Filtration of pulp and precipitation of nickel and cobalt from solutions with iron sulphide. During leaching, mainly iron is transferred to the solution; nickel and cobalt remain in a small amount of cake (the cake weight is reduced by almost ten times compared to the thermal decomposition product). As a result, up to 99% of non-ferrous metals are extracted into the concentrate, and the solution becomes more concentrated in iron.