Abstract: A new technology of vacuum distillation for the treatment of rare earth molten salt electrolytic slag is proposed to solve the current disadvantage of the low comprehensive recovery rate of rare earth, fluorine, and lithium in the slag.The influences of vacuum distillation temperature, time, vacuum degree, and particle size of raw materials on the separation of rare earth electrolytic molten salt slag are investigated.The results show that the removal efficiency of F and the recovery rate of fluoride are 99.6% and 95.3%,respectively.Compared with traditional technology, the new technology greatly simplifies the technical process and achieves high utilization of rare earth, fluorine, and lithium resources in the slag.