Thermodynamic evaluation and optimization of the LiF-NaF-KF-MgF2-CaF2 system using the modified quasi-chemical model

A complete critical evaluation of all available phase diagram and thermodyn amic data has been performed for all condensed phases of the LiF-NaF-KF-MgF 2-CaF2 system and optimized model parameters have been found. The model par ameters obtained for binary and ternary subsystems can be used to predict t hermodynamic properties and phase equilibria for the multicomponent system. The modified quasi-chemical model for short-range ordering (SRO) was used for the molten salt phase. For solutions with NaF or KF together with MgCl2 or CaCl2 the calculations indicate a large degree of ordering on the catio nic sublattice, with Mg-alkali and Ca-alkali second-nearest-neighbor (SNN) pairs being favored.