Lowest liquid phase saturation point temperature–phase separation–viscosity model for the optimal formulation of mixed fluoride salt

Abstract

Fluoride molten salts have a high melting point and latent heat of phase change, and can be used as a high-temperature phase-change heat-storage material. In this study, the Phase Diagram module of FactSage6.2 was used to calculate and draw the phase diagram of a quaternary fluoride salt system using two routes. The formulations meeting the melting-point requirement were further analyzed using the Equilib and Viscosity modules. We propose the “lowest liquid phase saturation point temperature–phase separation–viscosity” model to screen several sets of best experimental formulations. The experimental results prove the feasibility of the model, and the selected formulations offer the advantages of limited phase separation, good thermal stability, and high latent heat.