Thermodynamic modeling of the process of reduction of nickel and iron by a silicothermal process

Abstract

The results of studying the effect of silicon concentration of ferrosilicon: FeSi5 (5% Si), FeSi20 (20% Si), FeSi35 (35% Si), FeSi50 (50% Si), FeSi65 (65% Si) on the degree of nickel (ηNi) and iron (ηFe) reduction of the CaO-SiO₂-MgO-Al₂O₃-FeO-NiO-P₂O₅ multicomponent oxide system at a temperature of 1500°C by thermodynamic simulation are given. The HSC Chemistry 6.12 software package developed by Outokumpu (Finland) was used for the simulation. The chemical compounds Ni₃Si and Ni₅Si₂ with the corresponding thermodynamic characteristics are entered into the database. The calculations were performed by the “Equilibrium Compositions” subroutine at a gas pressure of 1 atm, containing 2.24 m³ N₂ as a neutral additive. The obtained modeling results indicate the thermodynamic possibility of nickel and iron reduction from the CaO-SiO₂-MgO-Al₂O₃-FeO-NiO-P₂O₅ oxide system by silicon of ferrosilicon. The degree of iron reduction increases from 88.8 to 91.4% with an increase in the silicon concentration of ferrosilicon [Si]_FeSi from 5 to 65%. The degree of nickel reduction with an increase in the silicon concentration of ferrosilicon remains almost unchanged and amounts to 99.8-99.7%. The degree of use of silicon is 92.1-94.5%. The chemical composition of the complex alloy - ferrosiliconickel is determined. The obtained simulation results can be used to develop the technology for producing ferrosiliconickel from nickel ore by silicothermic method.