Activities of P2O5 in Solid Solutions between Di-calcium Silicate and Tri-calcium Phosphate at 1 573 K

The knowledge of P2O5 activities in solid solutions between Ca2SiO4 and Ca3P2O8 is required for more effective dephosphorization. In the present study, firstly, the P2O5 activities in these solid solutions coexisting with CaO or CaSiO3 at 1 573 K were measured by equilibrating molten copper with oxide phases under a stream of Ar + H-2 + H2O gas mixtures. Subsequently, the sub-regular solution model was applied to Ca2SiO4-Ca3P208 solid solutions. The P2O5 activities calculated with the solution model agreed well with the present experimental results and the literature data. It was found that the P2O5 activity in Ca2SiO4-Ca3P2O8 solid solution coexisting with CaO was about 7 digits lower than that coexisting with CaSiO3