Abstract

A thermodynamic perturbation theory model is developed to take into account the additional charge–dipole contribution to the free energy of molten alkali halide systems, and it is used to describe the melt–crystal equilibria in binary salt mixtures with common anions. The liquidus lines in the binary phase diagrams LiF–NaF, LiF–KF, NaF–KF, NaF–CsF, and KF–CsF of the eutectic type are calculated. The error in describing the liquidus lines in the phase diagrams of the fluoride mixtures with the use of the tabulated ionic radii and polarizabilities is at most 15% as compared to the available FactSage data. The discrepancies between the calculated and published data become more noticeable for systems containing larger and more polarizable cations. The position of the eutectic equilibrium point is found to shift toward a low-melting-point component by 5–10%, and the eutectic point temperature is lightly overestimated in comparison with the experimental results and the FactSage data.

中文翻译：

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使用热力学扰动理论计算共晶盐混合物 LiF–NaF、LiF–KF、NaF–KF、NaF–CsF 和 KF–CsF 中的液相线

摘要

开发了一种热力学扰动理论模型，以考虑对熔融碱金属卤化物系统的自由能的额外电荷 - 偶极子贡献，并用于描述具有常见阴离子的二元盐混合物中的熔体 - 晶体平衡。计算了共晶类型的二元相图中 LiF-NaF、LiF-KF、NaF-KF、NaF-CsF 和 KF-CsF 中的液相线。与可用的 FactSage 数据相比，使用列表中的离子半径和极化率描述氟化物混合物相图中的液相线的误差最多为 15%。对于包含更大和更极化阳离子的系统，计算数据和公布数据之间的差异变得更加明显。