THERMODYNAMIC ESTIMATION ON THE REDUCTION BEHAVIOR OF IRON-CHROMIUM ORE WITH CARBON

The thermodynamics for reduction of iron-chromium ore by carbon is dis cussed. The thermodynamic properties of iron-chromium ore were evaluat ed from our previous work on the activities of constituents in the FeO . Cr2O3-MgO . Cr2O3-MgO . Al2O3 iron-chromite spinel-structure solid solution saturated with (Cr, Al)(2)O-3, and those of the Fe-Cr-C alloy were estimated by a sublattice model. The stability diagrams were dra wn for carbon reduction of pure FeO . Cr2O3, (Fe0.5Mg0.5)O . (Cr0.8Al0 .2)(2)O-3 iron-chromite solid solution, and South African iron-chromiu m ore. The evaluated stability diagrams agreed well with the literatur e data. It was concluded that the lowest temperature for reduction of FeO . Cr2O3 in the iron-chromium ore was 1390 K and a temperature high er than 1470 K would be necessary to reduce Cr2O3 in MgO . (Cr,Al)(2)O -3 in the prereduction process of iron-chromium ore. The composition o f liquid Fe-Cr-C alloy in equilibrium with iron-chromium ore was also estimated under 1 atm of CO at steelmaking temperature. The predicted metal composition showed reasonable agreement with the literature valu es.