Properties of some alkali fluoride–chloride salt mixtures I. Primary crystallization and density measurements

Abstract

The primary crystallization and density of the fluoride–chloride salt systems (i) NaF–LiCl and (ii) NaF–(LiCl + KCl) eutectic were determined experimentally using thermal analysis and the Archimedean technique, respectively. The corresponding liquidus curves for the two systems were constructed and compared. Molar volume and excess volume functions were computed from density data at different compositions and temperatures. The positive values of the excess volumes correspond to volume expansion that increases with temperature for both systems. The results suggest that as far as the primary crystallization and density behaviours are concerned, it is possible to replace the component, pure LiCl, in the fluoride–chloride salt system by the eutectic mixture of (LiCl + KCl) for the system's use as a potential electrolyte for aluminium electrolysis.