Reactions of antimony compounds with fluorine gas by thermogravimetric and differential thermal analyses and X-ray diffraction analysis

摘要

Antimony is one of the key fission products in the reprocessing of spent nuclear fuel by the fluoride volatility method because of the high volatility of antimony fluorides. Since the fluorination reaction of antimony compounds is not well understood, the reaction behavior of antimony compounds with F2was investigated by thermogravimetric and differential thermal analyses and X-ray diffraction analysis in this study. The target antimony compounds were antimony metal, SbF3, Sb2O3, Sb2O4, and Sb2O5. The fluorination reaction of antimony metal started at 150?°C, and the fluorination product was SbF3. SbF3volatilized completely by the reaction with F2above 190?°C; it was considered that volatile SbF5was formed by the reaction with F2. In the series of fluorination of the antimony oxides, Sb2O3, Sb2O4, and Sb2O5, they started to react with F2and volatilize at 330?°C as SbF5. During the fluorination of Sb2O3, Sb2O4was formed temporarily in the course of the reaction. Oxygen released from the fluorination reaction of a part of Sb2O3would oxidize remained Sb2O3to Sb2O4. The reaction mechanism for the fluorination of antimony compounds obtained in this study is applicable to evaluate the transfer of antimony in the reprocessing process of the fluoride volatility method.