Thermodynamic properties of liquid phase in the CaO·SiO2–CaO·Al2O3·2SiO2–2CaO·Al2O3·SiO2 system

Thermodynamic properties consistent with phase equilibria and calorimetric measurements were established for liquid phase in the system CaO·SiO2–CaO·Al2O3·2SiO2–2CaO·Al2O3·SiO2 using molecular regular solution models. The assessed thermodynamic data set involves enthalpy and entropy of formation of crystalline phases, heat capacity (Cp) data of solid and liquid pure components, enthalpy of mixing of liquid pure components, enthalpy and entropy of fusion of solid phases and phase equilibria experiments. Considerable inconsistency was found between experimental phase equilibria and calorimetrically measured enthalpy of the liquid solution. To fix thermodynamic properties of melt in studied system, which reproduce phase diagrams satisfactorily, considerable changes in enthalpy of mixing with respect to the original calorimetric data must be accepted.