Abstract Molten salt processes have been developed in various fields of engineering. In such a process, its efficiency and the quality of products would be enhanced when the used molten salt is effectively separated from the product and recycled into the process. Vacuum evaporation has been applied to recover molten salts due to the low vapor pressure and the high melting point. However, most of researches have been focused on the bulk salts evaporation. In this work, LiCl salt evaporation behavior from a porous solid was investigated to develop a post-treatment process of an electrolytic reduction process which uses LiCl as an electrolyte and produces porous solid products. The electrolytic reduction process is one of the main components of pyroprocessing to treat spent nuclear fuel and produce metallic uranium. Instead of using radioactive material, we prepared porous MgO chips and rods to determine the conditions and measure the behavior with different physical characteristics of the rods. The temperature and pressure were set to 700 s and 20 mTorr, respectively, and more than 70% of salt was removed within 5 h.