Abstract
The low-pressure distillation of FLiBe salt containing ThF(4) 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 BeF(2), while the slow distillation process was mainly attributed to the evaporation of ThF(4) and LiF complexes. Precipitation-distillation coupled method was employed for the recovery of FLiBe carrier salt. XRD analysis indicated that ThO(2) 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.