Computer thermodynamic modeling of obtaining ferroalloys from a mixture of leaching tailings of oxidized copper ores

Abstract

The article presents the results of computer thermodynamic modeling and experiments on the production of ferroalloys of the production of ferroalloys from a mixture of tailings for sulfuric acid leaching of oxidized copper ores from the Almaly, Ayak-Kodzhan, Aktogay, Kounrad, Shatyrkol deposits, containing (%): 65.2SiO₂; 14.2Al₂O₃; 7.4Fe₂O₃; 2.4K₂O; 2.7Na₂O; 6.6CаO; 2.8MgO; 0.2CuO. The simulations were carried out using the HSC-6.0 software package based on the Gibbs minimum energy principle, as well as the research planning method using a rotatable second-order plan (the Box-Hunter plan). Experiments on melting a mixture of tailings were carried out on the Tamma furnace in isothermal mode. The influence of temperature and the amount of carbon on the equilibrium degree of distribution of silicon, aluminum and the concentration of these metals in the alloy was determined. Based on the results obtained, it was found that the equilibrium interaction of a mixture of heap leaching tailings of copper ores with carbon and iron occurs with the formation of FeSi, FeSi₂, FeSi_2.33, Fe₅Si₃, FeSi_2.43, Fe₃Si, Si, SiO₂, Al, SiC, CaSiO₃, Al₂SiO₅, MgSiO₃, K₂SiO₃, Na₂SiO₃, Cu, CO. An increase in iron from 30 to 50% of the mass of the mixture of leaching tailings and temperatures from 1600 to 2000ºС increases the degree of extraction into the silicon alloy to 83.2%, and reduces the concentration of silicon in it from 40-41.41% (at 1800ºC) to 30-31%, aluminum at 2100ºС from 8.3% to 5.5%. Ferrosilicon of the FeSi₄₅ brand with the extraction of 74-81.9% Si from it is formed at 1780-1910ºС, 30% iron and 34% carbon, and the FeSi₂₅ brand with the extraction of 70-76% Si into it is formed in the temperature range of 1660-1730ºС in the presence of 43.5-50% iron. Determines the influence of temperature 1000-2100ºС and iron. To achieve high (≥80%) silicon in the alloy, a temperature of at least 1800ºС and an 80-minute duration of the process are required.