Thermodynamic and phase equilibrium model for the Li, Na, K, Mg, Ca, Mn// Cl, F system: Part II. MnF2-based ternary common-ion and reciprocal sub-systems

This study focuses on the development of a thermodynamic model for the Li, Na, K, Mg, Ca, Mn// Cl, F chloro-fluoride salt system, which may be used as a flux for recycling Mn-containing aluminum alloys. Using the CALPHAD approach, a consistent thermodynamic description of all condensed phases was obtained for the MnF 2 -containing sub-systems. The molten salt phase and the solid solutions were modelled using the Modified Quasichemical Model and the Compound Energy Formalism, respectively. This is the second of two papers on the optimization of the Li, Na, K, Mg, Ca, Mn// Cl, F system. The first article described the thermodynamic models for the six MnF 2 -based common-ion binary sub-systems while this second article is devoted to the MnF 2 -based common-ion ternary (LiF-KF-MnF 2 , LiF-NaF-MnF 2 , and NaF-KF-MnF 2 ) and reciprocal (KCl-KF-MnCl 2 -MnF 2 , NaCl-NaF-MnCl 2 -MnF 2 , and Na, K, Mn// Cl, F) sub-systems. The developed thermodynamic model was applied, using Gibbs energy minimization software, to investigate the behavior of manganese in molten salt treatments. Calculations indicate a generally weak affinity between manganese and the molten salt, suggesting that Mn is challenging to remove via conventional fluxing. • Thermodynamic modeling of MnF 2 -based ternary common-ion and reciprocal sub-systems. • The Modified Quasichemical Model was used to describe the energetics of the molten salt phase. • The Compound Energy Formalism was used for the thermodynamic description of all solid solutions.