The Power of Thermodynamic Modeling: Examples from Molten Halide Mixtures

Although thermodynamics is the science of energy transformations, structural models have often been very useful to describe and predict thermodynamic properties. An early example is Flood and Urnesʹ description of the KCl-MgCl2 phase diagram on the KCl side by assuming the presence of MgCl^2-(4). Examples will be given from aluminium chloride-alkali chloride systems where total vapor pressure of binary systems was determined. Through modeling, it was possible to describe the liquid phase, composition of the gas phase, and phase diagrams for binary and ternary systems. Determination of thermodynamic properties, which was nearly inaccessible for experimental determination, was also accomplished through modeling.