Article ID: ISIJINT-2024-243
The activities of components in Ca2SiO4-Ca3P2O8 solid solutions have been reported by preceding studies as the basic thermodynamic data for phosphorus removal in the steelmaking process. Since the reported activities contained the uncertainties accumulated from thermodynamic data, this study aimed to reevaluate the experimental results in the preceding studies. Firstly, the equilibrium constant of the following reaction used to calculate the P2O5 activities was measured at 1573 K through a gas equilibrium method.
2Pin Cu+5H2O(gas)=P2O5 in oxide+5H2(gas)
It was discussed that the use of the equilibrium constant determined in the present study could reduce the uncertainty in the P2O5 activities. Subsequently, the recalculated P2O5 activities at 1573 K and available thermodynamic data for the Ca2SiO4-Ca3P2O8 solid solution-containing system were compared in terms of the activities of components in the Ca2SiO4-Ca1.5PO4 ( = (1/2)Ca3P2O8) pseudo-binary system.