Evaluation of phosphorus reaction equilibrium in steelmaking

Abstract

Despite the extensive work done on the phosphorus reaction during steelmaking, for some conditions there are disagreements for the equilibrium between slag and metal. Not all the correlations for the phosphorus distribution ratio between slag and metal, as a function of slag chemistry, agree when compared for similar conditions. The disagreements are at low basicity and/or high FeO content. Therefore, the purpose of this study is to evaluate the phosphorus reaction equilibrium as it pertains to conditions in the EAF and BOF. Equilibrium experiments were conducted for selected conditions where disagreements exist for MgO saturation. Also, experiments using CaO crucibles, for which the slags are saturated with CaO rather than MgO, were conducted so that the MgO content could be varied and its effect determined. A modification to the existing correlation for the phosphorus equilibrium was made and good agreement with experimental data was obtained. Some uncertainties, with respect to plant data, still exist and are discussed.