Thermodynamic description of the AgCl–CoCl2–InCl3–NaCl system
Abstract Critical thermodynamic evaluations and optimizations of the AgCl–CoCl2, AgCl–InCl3, AgCl–NaCl, InCl3–NaCl and CoCl2–InCl3 systems were carried out in the present work within the framework of the CALPHAD approach. The molten salt phase was described by the Modified Quasi-chemical Model, while the Compound Energy Formalism with various lattice ratios was used to treat the terminal solid solutions. The two binary double salts (Na3InCl6 and Ag3InCl6) were treated as the stoichiometric compounds of which Gibbs energies were modelled following the Neumann-Kopp rule. All the model parameters were optimized in terms of the required phase equilibria and thermochemical data arising from experimental measurements and theoretical predictions (First-principles method and empirical equation). A set of self-consistent thermodynamic database for the AgCl–CoCl2–InCl3–NaCl quaternary system was finally derived by merging the Gibbs energies for relevant phases in all binary systems (model parameters of CoCl2–NaCl were adopted from the literature) based upon the Kohler–Toop interpolation technique in order to facilely calculate various phase equilibria and thermodynamic properties of the sub-ternary and quaternary systems. The calculated results involving multicomponent systems will support beneficial instructions in the related industrial processes.