Distillation and condensation characteristics of LiCl-KCl eutectic salts containing rare earth precipitates were investigated and a conversion of the rare earth oxychlorides to oxides was performed. The distillation flux was increased by about 1,000 times by reducing the pressure from 760 Torr to 0.5 Torr. The composition of the recovered salts was changed according to the condensed spot. The conversion temperature of the multicomponent oxychlorides was decreased when compared to that of a single component. It was found that the concentration of the chloride gas in the flue gas is an index to establish whether the conversion is completed or not.