Thermodynamic simulation of silicothermic chromium reduction process
https://doi.org/10.17073/0368-0797-2020-2-122-128
Abstract
Thermodynamic modeling of chromium reduction from the oxide system of the following composition was carried out, (wt %): 25.0 – 37.5 CaO, 25.0 – 12.5 SiO2 , 25 CrO3 , 5 FeO; 14 MgO, 3 MnO, 3 Al2O3 . Silicon of ferrosilicon of FeSi20, FeSi45, FeSi65 grades was used as a reducing agent in amount of 110 % of stoichiometrically needed for iron, manganese and chromium reduction. Modeling was performed on HSC Chemistry 6.12 software package developed by Outokumpu (Finland). Calculations were performed using “Equilibrium Compositions” module in the initial nitrogen medium at total pressure of 0.1 MPa and in temperature range of 1500 – 1700 °С with step of 50 °С. The thermodynamic characteristics of chemical compound CrO (II) was introduced into the database. Thermodynamic constants of CaCr2O4 compound presented in a database have been adjusted. Calculation results were presented in form of graphic dependences of change in degree of chromium reduction ηCr on temperature t, slag basicity (CaO)/(SiO2), and silicon concentration in ferrosilicon [Si]FeSi . It was shown that increase in the process temperature from 1500 to 1700 °C at (CaO)/(SiO2) = 2 reduces ηCr by 1.87, 6.04 and 7.38 % when using FeSi20, FeSi45 and FeSi65 reducing agents respectively. It was found that increase in (CaO)/(SiO2) from 1 to 3 at temperature of 1600 °C leads to an increase of ηCr 2 by 17.3, 14.2 and 12.5 % using FeSi20, FeSi45, and FeSi65 respectively. Increase in silicon concentration from 20 to 65 % in [Si]FeSi ferrosilicon facilitates an increase of ηCr by 9.5, 5.9 and 4.2 % at slag basicity of 1, 2 and 3 respectively and at temperature of 1600 °C. Chemical composition of metal was determined. Results of thermodynamic modeling can be used to calculate degree of chromium reduction from recovery period slags of the argon-oxygen refining process in stainless steel production.
Keywords
thermodynamic simulation,
oxide system,
reduction,
temperature,
slag basicity,
ferrosilicon,
metal composition
Supporting agencies: The work was performed according to the state assignment for IMET UB RAS and under the project No. 18-5-2345-56 of the Comprehensive Program of Ural Branch of RAS.
About the Authors
V. A. Salina
Institute of Metallurgy, UB RAS
Russian Federation
Russian Federation
Cand. Sci. (Eng.), Senior Researcher
Ekaterinburg
V. I. Zhuchkov
Institute of Metallurgy, UB RAS
Russian Federation
Russian Federation
Dr. Sci. (Eng.), Professor, Chief Researcher
Ekaterinburg
O. V. Zayakin
Institute of Metallurgy, UB RAS
Russian Federation
Russian Federation
Dr. Sci. (Eng.), Head of the Laboratory of Steel and Ferroalloys
Ekaterinburg
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For citations:
Salina V.A., Zhuchkov V.I., Zayakin O.V. Thermodynamic simulation of silicothermic chromium reduction process. Izvestiya. Ferrous Metallurgy. 2020;63(2):122-128. (In Russ.) https://doi.org/10.17073/0368-0797-2020-2-122-128
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