二元、三元和四元硝酸盐的热物理性质及相图分析及其在储热应用中的研究

Abstract This work investigates the phase diagram and thermophysical properties of the binary, ternary and quaternary nitrates containing NaNO 3 , KNO 3 , Ca(NO 3 ) 2 and LiNO 3 . We developed an equal-composition method to predict the eutectic point and the corresponding composition based on the CALPHAD method with the FactSage software. This approach enables the expansion of existing binary and ternary phase diagrams to a quaternary one while maintaining consistency with the ternary phase diagrams. The melting temperature at the eutectic point was predicted to be 382.19 K with the molar composition of 9.16 % NaNO 3 / 49.91 % KNO 3 / 13.93 % Ca(NO 3 ) 2 / 27 % LiNO 3 , respectively. The melting point, eutectic point, and specific heat capacity measured at the predicted eutectic point were 352.1 K, 383.9 K, and 1.30 kJ . kg −1. K −1 , respectively. The decomposition temperature was determined to be 833.17 K with thermogravimetric analysis method. This work provided an efficient way of constructing quaternary phase diagram for molten salts and could facilitate the selection of low melting point molten salts that applicable to the thermal energy storage applications.