Activities of FeO and P2O5 in dephosphorization slags Co existing with solid solutions between di-calcium silicate and tri-calcium phosphate

Abstract

Towards better understanding of the phosphorus removal from hot metal with low-basicity slags, electrochemical technique incorporating MgO-stabilized zirconia was conducted to measure simultaneously the activities of FeO and P2O5 within heterogeneous CaO-SiO2-P2O5-FeO slags. The FeO activity was fairly insensitive to the variation of Ca3P2O8 content in solid solutions between Ca2SiO4-Ca3P2O8, while the P2O5 activity increased with an increase in Ca3P2O8 content. By using the present values for activities, phosphorus distribution ratios were estimated between molten slag and carbon-saturated iron. The relationship between phosphorus distribution ratio and FeO content in molten slag was consistent with the phase diagram of the pseudo-ternary CaO-(SiO2+P2O5)-FeO system.