Modeling of metals reducing from B2O3-CaO-Fe2O3-ZnO melts by CO-CO2 mixtures

Abstract

Thermodynamic modeling technique has been developed to predict the conditions of metals reduction from oxide melt by gas during bubbling processes. The technique provides approximation to real systems with periodic removal of metal phase and gases from the working body. The given work presents thermodynamic modeling results of Zinc and Iron reduction processes from B2O3-CaO-Fe2O3-ZnО melts by СО-СО2 different composition mixtures in the 1273-1673 K temperature range. Approximation to real processes is used. Zinc and Iron oxides content in the melt and its reducing degree have been estimated during the calculations. Three stages of the process have been obtained by the calculations. Reducing of Fe2O3 to Fe3O4 and FeO is realized in the first stage. Concentration of Fe2O3 (СFe2O3) decreases almost to zero while СFe3O4 и СFeO have been increased simultaneously. Concentration of СFe3O4 reaches its maximum to the end of process. Transition of Fe3O4 → FeO takes place in second stage when СFeO reaches its maximum, and Zinc and Fe begin its reducing. Temperature increase promotes metallization by Zinc, but decreases by Iron. An increase of input gas CO/CO2 ratio leads to Fe reducing degree. It thereby ensures required indicators of the Zinc selective reduction achievement but requires more gas consumption. The relationships between CZnO and φZn depending on temperature and amount of reducing input gas consumption have been obtained. Given work results may be useful for precut estimation of the probable parameters of Zinc distillation process from the melt. Besides, these results may be useful as the basis for the experimental results analysis.