Chemical and phase transitions in oxidized manganese ore in the presence of carbon

Abstract

In the present work, thermodynamic modeling of the chemical and phase transitions in a system consisting of oxidized manganese ore and reducing agent (carbon) is based on Astra 4 software developed at Bauman Moscow State Technical University. The phase composition and equilibrium characteristics are calculated by means of a database regarding the properties of individual materials. The database in Astra 4 software consists of thermodynamic, thermophysical, and thermochemical properties of materials. It includes data systematized at the Institute of High Temperatures, Academy of Sciences of the USSR and at the United States National Standards Bureau; data published in journals, monographs, and handbooks; and also data analyzed and calculated at Bauman Moscow State Technical University. The chemical and phase transformations in the system are simulated in the range 1573–2573 K, with 5, 10, and 15% C in the system, at a pressure of 0.1 MPa. Modeling shows that the maximum conversion of manganese to Mn3Si3 (in the condensed state) is 95.3 at T = 1873 K, with 30% carbon in the system. With further increase in temperature, the manganese begins to enter the gas phase. In comparison with manganese, silicon is less easily reduced and, with increase in the temperature, it begins to enter the gas phase. The best temperature range for the reduction of silicon is 1773–1873 K, with 15–30% C in the system. Calculation of the iron transfer αFe (%) as a function of the temperature and the carbon content indicates that the temperature range 1773–1873 K is optimal, with 15% C. On the basis of thermodynamic modeling of the phase transitions in a system consisting of oxidized manganese ore and reducing agent, it is possible to assess the possibility of producing ferrosilicomanganese by the electrosmelting of Western Kamys ore, which is hard to enrich.