V. A. Salina, V. I. Zhuchkov.
ABSTRACT
To study the possibility of the reduction process of elements from the multicomponent Cr2O3–FeO–CaO–SiO2–MgO–Al2O3 liquid system the thermodynamic simulation was made. The system initial state parameters were: the temperature range (t) 1500–1800°С with the step of 100°C, the total pressure 0.1 MPa and the amount of nitrogen of 2.24 m3. The purpose of the work is to study the effect of the amount of dust of gas purifications in the charge on the process of producing ferrochrome. The composition of the oxide system corresponded to chrome ore (38% Cr2O3; 11.1% FeO; 0.17% CaO; 15% SiO2; 29.7% MgO; 6% Al2O3) and gas treatment dust (15.5% Cr2O3; 7.5% FeO; 0.8% CaO; 67.3% SiO2; 7.2% MgO; 1.7% Al2O3) during smelting of medium-carbon ferrochrome. The amount of added dust was 0; 5; 10; 20%. The carbon was used a reducing agent. The consumption of reducing agent was increased by 10% of the stoichiometry for the reduction of Fe and Cr and by 8% of the metal mass for the formation of iron, chromium and silicon carbides. The simulation was performed using the HSC Chemistry 6.12 software package developed from Outokumpu, Finland. The thermodynamic data of CrO(II) compound were entered into the software
package’s database. The thermochemical characteristics of compounds CaCr2O4, SiC, Cr3C2, Cr7C3, Cr23C6, Fe3C. It was found that increasing the melt temperature from 1500 to 1700°C increases the degree of chromium reduction (ηCr) from 90.2 to 94.8% for various dust contents in the system. An increase in the amount of dust in the system from 0 to 20% decreased ηCr. Moreover, the largest ηCr value is characteristic of the composition of the system no dust and is equal to 94.8% at (CaO) + MgO)/(SiO2) = 2.0 and melt temperature 1700°C. The chemical compositions of metal and slag melts are determined. The Cr content in the metal was 64–65.6%. The simulation results can be used in the analysis of reduction processes of chromium-containing systems and alloys production technology.
KEY WORDS:
composition, system, carbon, temperature, heat, melt, phase, thermodynamic simulation, degree of reduction, liquid phase state
DOI: 10.31857/S023501062105011X