Thermochemistry of Heterogeneous CaO–P₂O₅–SiO₂–Fe_xO and CaO–P₂O₅–CaF₂–Fe_xO Slags

Abstract

In steelmaking processes, because of environmental requirements and health considerations, there is a strong incentive to reduce slag volume. The key to meet this requirement is the better understanding of phosphorus removal, which relies on the knowledge of the thermodynamic properties of slags and fluxes used for dephosphorization. In this study, the liquidus compositions of the four-phase assemblages in the quaternary systems of CaO–P₂O₅–SiO₂–Fe_xO and CaO–P₂O₅–CaF₂–Fe_xO were determined by employing electron probe microanalysis. Measurements were also made on the Fe_xO activities by employing an electrochemical technique involving stabilized zirconia electrolyte.