氟化熔盐结构对其气液相平衡行为的影响研究

Molten salts have been used in industries and science and technology fields on account of its many excellent characteristics. The gas-liquid phase equilibrium of molten salt concern the efficiency and safety during the use phase and even determine the possibility of the application. The coordination structure of molten salt is the main influence factor of the gas-liquid phase equilibrium state. In this project the simple eutectic LiF-NaF-KF ternary sytem and KF-ZrF4 complex binary system are studied by molen salt time of flight mass spectra technique, infrared spectroscopy technique and Knusen effusion and boiling point vapor pressure measurement. After data of the vapor pressure, gas species and the coordination structure of liquid salt are obtained, the interaction characteristics between gas-liquid phase equilibrium and coordination structure of molten salt will be explored.

高温熔盐由于其优异的特性，被广泛应用于工业及各科技领域中。熔盐的气液相平衡行为不但决定了熔盐在液态状态下的稳定性，对熔盐在使用过程中的安全，效率及应用价值具有重要意义。高温下液相的配位结构是气液相平衡的主要影响因素，本项目将以性质稳定的典型的LiF-NaF-KF和KF-ZrF4熔盐为研究对象，借助熔盐气相组分分析、熔盐红外、拉曼光谱技术以及Knusen质量隙透、沸点法蒸汽压测试技术，在获得这两种熔盐气相组成、液相配位结构、蒸汽压的基础上，系统探讨熔盐配位机构对气液相平衡的影响规律。

在本项目的支持下，我们调试完成了高温熔盐蒸气压测试仪，并采取将热重法与Knusen隙透两种方法有效相结合的方式，建立了熔盐体系饱和蒸气压的测量方法；开展了氟化盐的热动力学平衡研究；同时结合飞行时间质谱研究对熔盐热分解反应机理进行了实验研究，揭示了在气液相平衡过程中熔盐中热分解反应存在着中间态过程，这对优化和提高熔盐的热稳定性的应用具有重要参考价值。