Thermochemistry and Models of Ionic and Non-Ionic Melts

Abstract

Most molten salt industrial processes , for instance electrolytic elaboration of metals from melts, involve compromise between several parameters to be optimized. Thermodynamic properties play an important role and the choice both of suitable electrolyte and molten salts to be electrolyzed is directely related to the operation temperature and to the "average valency" of the electrolytic bath. Experimental thermochemical investigations conducted by high temperature calorimetry, differential enthalpic analysis, differential scanning calorimetry can provide information on phase equilibria in the melt. From a theoretical point of view, the molten salt mixtures considered in those investigations are not simple since they involve i) ions with different valency , ii) ionic and non-ionic components and iii) several components. Classical models used for the most simple molten salt mixtures cannot be used and suitable modelling involving complex species, should be developed.