Solubility of Carbon Dioxide in LiF–Li2CO3 Molten Salt System

The solubility of carbon dioxide in a LiF–Li2CO3 molten salt system was determined using a pressure differential method. With increasing holding temperature, the solubility of CO2 in LiF–Li2CO3 melts decreases rapidly. The influence of the alkali metal fluoride of XF(X = K, Na) content from 5% to 25% on the CO2 solubility was considered. The CO2 solubility in LiF–Li2CO3–XF melts decreased with increasing temperature and concentration of XF. The calculated thermodynamic data for CO2 dissolved in these melts revealed that the reaction between CO2 and a carbonate ion was exothermic. At 630 °C, KF decreased the CO2 solubility more effectively than NaF. When the mole fraction of LiF was 50% in LiF–Li2CO3, the CO2 solubility reached a maximum of 6.8 × 10–4 (molCO2/molmelt) at 640 °C.