Absolute thermodynamic properties of molten salts using the two-phase thermodynamic (2PT) superpositioning method

J Wang and B Chakraborty and J Eapen, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 16, 3062-3069 (2014).

DOI: 10.1039/c3cp52632a

We show that the absolute thermodynamic properties of molten salts (mixtures of KCl and LiCl) can be accurately determined from the two- phase thermodynamic (2PT) method that is based on superpositioning of solid-like and gas-like (hard-sphere) vibrational density of states (DoS). The 2PT predictions are in excellent accordance with those from the thermodynamic integration method; the melting point of KCl evaluated from the free energy and the absolute entropy shows close conformity with the experimental/ NIST data. The DoS partitioning shows that the Li+ ions in the eutectic LiCl-KCl molten mixture are largely solid-like, unlike the K+ and Cl- ions, which have a significant gas-like contribution, for temperatures ranging from 773 K to 1300 K. The solid- like states of the Li+ ions may have practical implications when employed for chemical and nuclear reprocessing applications.

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