Thermodynamic evaluation and optimization of the Li, Na, K, Mg, Ca, Sr // F, Cl reciprocal system

A complete critical evaluation of all available phase diagram and thermodynamic data has been performed for all condensed phases of the (LiF + LiCl + NaF + NaCl + KF + KCl + MgF2 + MgCl2 + CaF2 + CaCl2 + SrF2 + SrCl2) system, and optimized model parameters have been found. The (LiCl + NaCl + KCl + MgCl2 + CaCl2 + SrCl2), (LiF + NaF + KF + MgF2 + CaF2 + SrF2), and (LiF + LiCl + NaF + NaCl + KF + KCl + MgF2 + MgCl2 + CaF2 + CaCl2) subsystems have been critically evaluated previously. The model parameters for the common-ion binary, common-anion ternary, and reciprocal ternary subsystems (i.e. systems with two cations and two anions) can be used to predict thermodynamic properties and phase equilibria for the multicomponent reciprocal system. The Modified Quasichemical Model in the Quadruplet Approximation was used for the molten salt phase. This model takes into account both first-nearest-neighbor (cation–anion) and second-nearest-neighbor (cation–cation and anion–anion) short-range ordering, and the coupling between them. Finally, the CaFCl–SrFCl solid solution was modeled using the Compound Energy Formalism.

► A thermodynamic model for the Li, Na, K, Mg, Ca, Sr // F, Cl reciprocal system. ► The Modified Quasichemical Model for short-range ordering was used for the liquid. ► The (Ca, Sr)FCl solid solution was modeled using the Compound Energy Formalism.