Abstract:In order to obtain thermal storage molten salts with low melting point and high thermal stability temperature used as thermal storage medium in concentrating solar power, 12 kinds of NaCL-KCl-ZnCl2-LiCl quaternary mixed molten salts were prepared by doping anhydrous LiCl with different mass fractions into two eutectic points E1 and E2 of NaCl-KCl-ZnCl2 ternary system. Then, differential scanning calorimetry (DSC) melting point test, thermogravimetric (TG) dynamic thermal stability test, 52 hours static thermal stability test and molten salt density determination were carried out. The DSC results show that the lowest melting point of the prepared quaternary mixed molten salt is 174.2 ℃, which is 36.2 ℃ lower than the melting point of E1 eutectic point 210.4 ℃ before doping, and the corresponding latent heat of phase transition is 78 J/g. TG dynamic thermal stability and long-term static thermal stability experiments show that the thermal stability temperature of the newly quaternary mixed salt is 700 ℃. The liquid density test of molten salt is 2.35—2.58 g/cm3 at 250—700 ℃. The newly quaternary molten salt mixture may be used as thermal storage medium for solar thermal power generation.