Dissolution Mechanism of YbOF in (LiF-CaF₂)_eut. Molten Salt

The dissolution mechanism of YbOF in a fluoride-containing (LiF-CaF₂)_eut. molten salt is the basis for analyzing the structure of the resulting medium and optimizing the electrolytic preparation of rare-earth Yb alloys. In this study, isothermal saturation was used to analyze solubility changes of YbOF in the (LiF-CaF₂)_eut. system. Quantum chemical and molecular dynamics ab initio methods were used to study the basic properties of the components of the (LiF-CaF₂)_eut.-YbOF system and the microscopic structural changes during the dissolution process. In addition, structural changes in the YbOF-saturated (LiF-CaF₂)_eut. system were analyzed by combining cryogenic-temperature Raman spectroscopy with experimental methods. The results show the solubility of YbOF increased linearly in the temperature range of 1073-1323 K. As the melting temperature exceeded 1073 K, LiF and CaF₂ gradually dissociated into Li⁺, Ca²⁺, and F^-. In the initial stages of YbOF dissolution (1073-1173 K), the Yb-F bond was less stable than the Yb-O bond; YbOF dissociated into YbO⁺ and F^- in this temperature range. When the temperature was increased above 1173 K, YbO⁺ further dissociated into Yb³⁺ and O^2-. Overall, the dissolution of YbOF did not affect the main structure of the (LiF-CaF₂)_eut. system.