Reduction Equilibria at the Final Stage of Reduction of Quaternary Calcium Ferrite with CO-CO2 Gas Mixtures

Quaternary calcium ferrite was synthesized from chemical reagents of Fe2O3, CaCO3, SiO2, and Al2O3 and the reduction equilibria at the final stage of reduction with CO-CO2 gas mixtures were studied. The results obtained are summarized as follows : 1) Dicalcium ferrite, which is produced during the reduction of binary calcium ferrite, is not found in the reduction of quaternary calcium ferrite. The reduction stage from dicalcium ferrite to iron and CaO is therefore not existent in the reduction of quaternary calcium ferrite. 2) The reaction at the final stage of carbon monoxide reduction of quaternary calcium ferrite is given by the following equation. 'FeO' (s)+ CO(g) = Fe(s)+ CO2 (g) where 'FeO' is the wustite which contains CaO, SiO2 and Al2O3 as solid solutions. The temperature dependence of the apparent equilibrium constant K(= PCO2/PCO) of the reaction which is the final stage of reduction of quaternary calcium ferrite synthesized in this study is given by the following equation. K = exp (-2.785 + 2 042/T) ± 0.003 (1 0731 326 K)