Technological capabilities for metallurgical processing of industrial products in polymetallic ore preparation and copper smelting slag depletion in the Pobeda smelting unit

The study is aimed at the urgent problem for disposal of accumulated copper-containing enrichment by-products. The equilibrium distribution of Pb, Zn and S was determined in the "Cu-Zn intermediate product - CaCO₃ - C - sulphide-metal product - gas phase (Pb, Zn sublimates)" system corresponding to the calcination conditions of the copper-zinc sulphide intermediate product. In order to solve this problem, the thermodynamic modelling method was applied using the HSC Chemistry 6 software application package (Finland). A copper-zinc sulphide intermediate product with the following composition (wt%) was taken as the initial reagents: Cu - 10.14, Zn - 22.70, Pb - 0.49, Fe - 21.00, S - 36.29, CaO - 0.51, SiO₂ - 2.49, Al₂O₃ - 5.47, having 80.0 wt% C coke and 94.91 wt% CaCO₃ limestone. Additionally, the component equilibrium distribution in the copper-zinc intermediate product between the initial reagents and the products of calcination was simulated, depending on the temperature characteristic of solid-phase reactions. A thermodynamic modelling of the component solid-phase equilibrium distribution in the mixture under study at a temperature of 1150 ºС was carried out. The possibility of 90% zinc extraction into the gas phase, metallisation of iron and the formation of CaS was demonstrated. Following dezincification, the solid residue was established to contain CaS, Fe_met and C in amount of 48.7, 15.0 and 3.4 wt%, respectively, with the possibility of application for autogenous smelting slag depletion in the Pobeda smelting unit. The performed thermodynamic modelling of metallurgical systems - in particular, the calcination of copper-zinc materials mixed with limestone and coke - demonstrated the possibility of solving optimisation problems using information technologies. The technological efficiency of a sulphide-metal product application is evidenced by the example of an electric furnace used to reduce the converter slag composed by Cu, Zn, Fe and SiO₂ in amounts of 3.75, 6.64, 43.79 and 21.88 wt%, respectively. The matte (> 20% Cu) with a copper recovery of 96% and dump slag (0.3% Cu) was obtained. The consumption of sulphide-metal product in this case comprised 15% of the slag weight.

metallurgy of copper, slag, Pobeda smelting unit, flue gases, thermodynamic modeling, copper-zinc middling