Abstract:The supporting electrolyte in the molten salt electrolysis process needs to have good conductivity, low viscosity, and take into account the physical and chemical properties such as surface tension, density, and melting temperature. In this paper, based on the previous research of molten salt electrolysis process, the effects of different temperatures (750℃, 800℃, 850℃, 900℃, 950℃, 1000℃) and different molar ratios (LiF/NaF=1.5,1.2,1.0,0.8,0.6,0.4) on the density, viscosity, surface tension and conductivity of LiF-NaF molten salt mixture of fluoride binary system were studied by means of high temperature melt physical property test system. The results show that the density of the LiF-NaF molten salt system decreases with the increase of temperature and increases with the decrease of the molar ratio of LiF to NaF. The viscosity of LiF-NaF molten salt system decreases with the increase of temperature, and tends to be stable after 950℃. It decreases with the decrease of the molar ratio of LiF to NaF. The surface tension of the LiF-NaF molten salt system decreases with the increase of temperature and the decrease of the molar ratio of LiF to NaF. The electrical conductivity of LiF-NaF molten salt system increases with the increase of temperature and decreases with the decrease of LiF/NaF molar ratio. When using LiF-NaF molten salt system, the most suitable molar ratio and temperature should be selected for specific electrolysis target products.