| Abstrakt: |
When preparing rare earth Yb alloy by electrolysis, the thermodynamic data and phase diagrams for LiF–CaF2 and LiF–YbF3 fluoride molten salts provide the basis for optimizing the electrode reaction conditions. For the LiF–CaF2 and LiF–YbF3 molten salt systems, an ideal solution model is used to describe the gas phase and components, and a displacement melt model is used to describe the Gibbs free energy of the melt phase. A phase diagram is constructed to evaluate and establish a thermodynamic model consistent with the measured data. Moreover, the dominant regions of the LiF–CaF2 and LiF–YbF3 molten salt system diagrams after introducing O are calculated. A Bayesian optimization algorithm based on a probability model is used to optimize the Gibbs free energy parameters of the LiF–CaF2 and LiF–YbF3 systems; these parameters are used for phase diagram calculations of the system. The obtained results are highly consistent with the experimental results. A figure of the optimized dominant region after introducing O shows that the temperature increases from 1173 to 1273 K, the predominant areas of Li(g), Ca(l), and Yb(l) expand, the [Me/MeO] and [Me/MeF] (Me = Li, Ca, Yb) equilibrium lines of O and F partial pressures increase, and the affinities for Ca and O in the Li–Ca–F–O system are stronger than the affinity for Li. After introducing O into the LiF–YbF3 system, competitive oxidation with F forms YbOF. Furthermore, LiF and YbF3 interact to form LiYbF4. [ABSTRACT FROM AUTHOR] |
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