Abstract:Firstly, a systematic thermodynamic evaluation and optimization of CaCl2-CaO, CaC12-CaF2 and CaO-CaF2 systems were carried out based on the Calphad method. The substitution solution model was used to describe the Gibbs free energy of liquid and solid solution phases. All intermediate phases, because of their limited solid solubility, were approximately treated as stoichiometric compounds and their free energies were defined according to the Neumann-Kopp rule. Secondly, the optimized model parameters of all sub-binary systems were extended to the CaCl2-CaF2-CaO ternary system by using the Muggianu geometric solution model. Finally, samples with the eutectic composition were prepared and then tested by the Differential Scanning Calorimetry (DSC) method. A self-consistent thermodynamic database of CaCl2-CaO-CaF2 ternary system was obtained by introducing ternary interaction parameters to make the calculation results consistent with the experimental data.