Thermodynamic Optimization and Calculation of the LaCl₃-CaCl₂ System

Abstract

A thermodynamic evaluation of the binary LaCl3-CaCl2 system was carried out by using CALPHAD method. The Modified Quasihelical Model was defined in order to describe the Gibbs energies of the liquid phases, and the model parameters were optimized from the experimental thermodynamic and phase diagram data. The phase diagram and the enthalpy of mixing of LaCl3-CaCl2 liquid were calculated. For LaCl3-CaCl2, a calculated eutectic point was observed at 924.82 K, 34.8 mol. % LaCl3. The calculated enthalpy of mixing is exothermic, the minimum was found at approximately 30 mol. % LaCl3. The thermodynamic properties and the phase diagram calculated from the optimized parameters agree well with the experimental data.