Experimental study and thermochemical assessment of the reciprocal system Li+, K+//Cl-, CO32-

In this work a new thermodynamic dataset of the reciprocal system Li+, K+//Cl-, CO32- was generated by using Calphad method with FactSage. After collecting and analyzing the available thermodynamic data in the literature, experiments were designed to improve the comprehensiveness of the new database. Specifically, Differential Thermal Analysis (DTA) was used (1) to confirm the eutectic temperature of the K2CO3-KCl system, (2) to check the solid solubility in the K2CO3-Li2CO3 system and (3) to measure the phase equilibria of the diagonal sections (i.e. Li2CO3-(KCl)(2) and K2CO3-(LiCl)(2)) in the reciprocal system. In addition, the heat capacity of the intermediate compound LiKCO3 was measured by three types of Differential Scanning Calorimetry (DSC) and its phase transformation was studied by High temperature X-ray Diffractometry (HTXRD). Based on the literature data and the present experimental results, the thermodynamic data on pure LiCl, all sub-binary systems and the reciprocal system were reassessed in the new database, which can be used to calculate and predict the thermodynamic properties of the salt mixtures in the reciprocal system Li+, K+//Cl-, CO32- more precisely and reliably.