Thermophysical properties of liquid chlorides from 600 to 1600 K: Melt point, enthalpy of fusion, and volumetric expansion

Abstract

Melt point, enthalpy of fusion, and volumetric expansion of single- and multi-component liquid chlorides {NaCl, KCl, LiCl, MgCl2, CaCl2, UCl3} were measured experimentally. These properties and materials are relevant in applications such as heat transfer, liquid nuclear fuel, and pyrochemical processing. A novel method for density measurement by neutron radiography was shown to produce high-quality data, consistent with reference literature where available, and allowed measurement of some materials for the first time. This method is especially useful in the characterization of sealed sample crucibles, given the ability of neutrons to penetrate the containment and surrounding furnace material. The results of this study are presented within the context of a comprehensive review of the available published data. The purpose of this review is to integrate measurements of the thermophysical properties of liquid chlorides into empirical descriptions of the relationships between composition, temperature, and thermophysical properties. A model for the prediction of the density of mixtures of liquid chlorides is proposed and demonstrated within a case study of the {NaCl + x mol% UCl3} system. A discussion of saturated vapor pressure as a function of temperature is presented as a supplemental interpretation of potential deviation from ideal mixture behavior, which remains an area active research.