Use of the Soft-Sphere Equation of State to predict the thermodynamic properties of the molten salt mixtures LiF-BeF_2, NaF-BeF_2, and KF-BeF_2

摘要

A Soft-Sphere Equation of State for the calculation of the thermodynamic properties of molten fluoride salt mixtures is presented. The mixtures considered were binary mixtures of beryllium difluoride (BeF_2) and alkali fluorides, which include lithium fluoride (LiF), sodium fluoride (NaF), and potassium fluoride (KF). The parameters of the Equation of State were determined by multi-property non-linear regression between experimental data and values calculated from the equation. A mixing rule was developed to represent the thermodynamic properties of the binary mixtures. The correlations are valid in the liquid phase for temperatures ranging from 550 K to about 1200 K, depending on the salt. Comparison of the experimental data to values calculated from the correlations indicates that densities can be calculated to within ±4%, enthalpies within ±5%, and heat capacities within ±6%.