Thermodynamic Simulation of Joint Pyrometallurgical Processing of Oxidized Nickel Ores and Sulfide Copper Ores

Abstract

The results of thermodynamic simulation of phase formation under conditions of joint reductive and sulfidating melting of oxidized nickel ores and sulfide copper ores are presented. The heating of a working body that is close in concern of phase composition to a mixture of nickel ores and copper ores with CaO and carbon taken in a weight ratio of 100 : (0–60) : 10 : (0–5) transforms the initial compounds, as well as changes the forms of existence of non-ferrous metals. At 1200–1500 °C, an oxide and sulfide mass is formed, mainly represented by troilite, quartz and metasilicates of iron, magnesium, aluminum and calcium. Iron is distributed between troilite, ferrosilite, fayalite, hedenbergite, wustite, and metallic phase. Nickel, copper and cobalt are found in the form of primary sulfides and metals. Separation of the working body into the sulfide-metal and oxide groups of the phases makes it possible to predict the production of matte, which concentrates nickel, cobalt and copper quantitatively. The addition of a carbon reductant increases the metallization of matte, which determines the growth of extraction of nickel, cobalt and copper into the matte. Melting (1300 °C) of a charge consisting of nickel ore, copper ore cinder (desulfurization degree after roasting is 78–93 %), CaO, and carbon taken in a weight ratio of 100 : (60–80) : 10 : (1–3) will allow to allocate the matte (10.4 % of charge), which meets the requirements of existing enterprises. The chemical composition of matte, % wt.: 61.5 Fe, 25.9 S, 6.3 Ni, 4.2 Cu, 0.79 Co, 1.2 Zn, 0.08 Pb, 0.01 As. A low level of desulfurization after melting (1–3 %) ensures the ecological efficiency of the proposed method of processing of raw materials. The obtained information is useful for improving the technology of processing of refractory ores