Recovery of FLiBe from ThF4–FLiBe salt using precipitation–distillation coupled method

Abstract

The low-pressure distillation of FLiBe salt containing ThF₄ was carried out at 1223 K and <10 Pa using thermogravimetric equipment. The weight loss curve indicated a rapid distillation stage at the beginning of distillation, followed by a slow stage. The composition and structure analyses showed that the rapid distillation process originated from the evaporation of LiF and BeF₂, while the slow distillation process was mainly attributed to the evaporation of ThF₄ and LiF complexes. Precipitation–distillation coupled method was employed for the recovery of FLiBe carrier salt. XRD analysis indicated that ThO₂ was formed and remained in the residue with the addition of BeO. Our results showed that the combination of precipitation and distillation treatment was an effective way to recover carrier salt.