Abstract: Low pressure distillation is a preferred technology for recycling the fluoride carrier(⁷LiF-BeF₂) of molten salt reactor system. In this study, the thermal weight reductions of the LiF salt during low pressure distillation were observed using a salt evaporation furnace for the thermogravimetric analysis, and the evaporation rate of LiF salt was investigated under different pressures and evaporation temperatures. It was found that the evaporation rate of LiF increased sharply with increasing evaporation temperature as well as decreasing pressure. This may contribute to the boiling of LiF salt under low pressures. The effect of the boiling of LiF salt on the recovery of fluoride was also studied in this work. These results are not only important to understand the distillation behaviors of LiF salt but also provide critical information for parameter optimization of the carrier recovery.