Calculation of Activities of the Constituents in Fe_tO-(CaO+MgO)-(SiO₂+P₂O₅) Slags by Regular Solution Model

Abstract

The chemical equilibria of gas-slag-metal reactions have been discussed to clarify the applicability of LUMSDEN'S regular solution model to oxygen distribution in steelmaking process. The slage studied are Fe_tO-CaO, Fe_tO-CaO-SiO₂, Fe_tO-MgO-SiO₂, Fe_tO-(CaO+MgO)-SiO₂ and Fe_tO-(CaO+MgO)-P₂O₅ systems. The influence of slag composition on the activity of iron oxide and the Fe³⁺/Fe²⁺ ratio has been discussed.
It has been confirmed that the regular solution model is satisfied over wide composition range in above-mentioned steelmaking slags except for SiO₂ saturation and FeO rich region. In has been possible by the use of the model to calculate activities of the constituents in Fe_tO-(CaO+MgO)-(SiO₂+P₂O₅), iso-activity lines for each component in Fe_tO-CaO-SiO₂ slags and contours of α_FetO in Fe_tO-MgO-SiO₂ slags.