Activity of Iron Oxide in Steelmaking Slag

Most refining reactions in steelmaking involve oxidation of impurity element(s). The product(s) of oxidation either dissolve in the slag or escape as gaseous phase. The activities of oxygen in the metal (hO), and that of “FeO” in slag (aFeO), are major factors controlling these chemical reactions. The activities of oxygen and “FeO” are thermodynamically related, provided equilibrium distribution of oxygen between the slag and the metal is attained. This enables direct estimation of one parameter from the other. A thorough knowledge of the variation in activity of FeO, and factors affecting the same, is therefore of great importance in the process metallurgy of steelmaking. The present work experimentally measures the activity of FeO in steelmaking slags and attempts to develop a correlation for estimation of γ(FeO) as a function of temperature and chemical composition of the slag.