Advancements in Understanding Molten Salt Mixing Enthalpy Using Molecular Interaction Volume Model

Recent research has introduced a molecular interaction volume model (MIVM) to enhance the understanding of mixing enthalpy in molten salt systems. This study, conducted by Vitaliy G. Goncharov and a team of 13 authors, focuses on the mixing of LaCl₃ with a eutectic mixture of LiCl-KCl at temperatures of 873 K and 1133 K. The findings, published on arXiv, reveal that traditional empirical models often lack clear physical interpretations, which can hinder the understanding of thermodynamic behaviors in multicomponent systems.

The MIVM integrates experimental data from high-temperature melt drop calorimetry with simulations from ab initio molecular dynamics (AIMD). This approach allows for a more accurate extrapolation of excess Gibbs energy and the activity of La³⁺ ions within the molten salt system. Notably, the study found significant discrepancies when comparing predicted mixing enthalpies derived directly from molecular dynamics trajectories with those obtained through the MIVM framework.

The implications of this research are particularly relevant for industries involved in pyrochemical separations, especially concerning lanthanides, which are critical in nuclear applications. The MIVM's ability to generalize findings across various molten salts represents a significant advancement over existing methodologies, potentially improving processes in nuclear and separation sciences.

For further details, the study can be accessed via arXiv under the citation: Goncharov, V. G., et al. (2024). Molecular interaction volume model of mixing enthalpy for molten salt system: An integrated calorimetry-model case study of LaCl₃-(LiCl-KCl). arXiv:2408.16943.