三元水盐体系冰点和共晶点的测定、相图表达及计算

发布时间：2018-04-22 16:56

本文选题：水盐体系 + 共晶点　；参考：《化工学报》2017年09期

【摘要】：针对Na~+//Cl~-,NO_3~--H_2O、Na~+//Cl~-,SO_4~(2-)-H_2O和Na~+,K~+//Cl~--H_2O 3个三元水盐体系,测定了不同组成时溶液的冰点、共晶点以及降温过程的析盐规律,绘制出三元体系温度-组成立体相图。结果表明:三元体系的冰点、共晶点、相关系与组成可用三棱柱表达,3个三元水盐体系在共晶点温度下均无复盐存在,各含有1个两盐与冰的共晶点,3条单盐与冰或盐盐的共晶线,1个冰和两个单盐结晶区;用三元体系温度-组成立体相图能更直观地表达三元水盐体系的结晶区、冰点、共晶点和溶液组成的关系,可以判断溶液降温过程中的盐或冰的析出类型、温度;同时建立了冰点经验公式,应用经验公式和过量吉布斯自由能模型预测三元体系的冰点和共晶点,计算值和实验值吻合良好。
[Abstract]:For the Na / / Cl / Cl-No3 / H _ 2O-Na ~ / / Cl-O _ 4 / so _ 4 / S _ 4 and Na ~ / / / Cl-H _ 2O / H _ 2O ternary water-salt systems, the freezing point, eutectic point and salt-evolution law of the solution at different compositions were measured, and the thermo-composition stereoscopic diagram of the ternary system was drawn. The results show that the freezing point, eutectic point, phase relation and composition of the ternary system can be expressed by triangulars, and there is no double salt in the three ternary water-salt systems at eutectic point temperature. Each eutectic point containing two salts and ice has three eutectic lines, one ice and two single salt crystalline regions. The ternary system temperature and composition stereoscopic phase diagram can more intuitively express the crystalline region and freezing point of ternary water salt system. The relationship between eutectic point and solution composition can determine the precipitation type and temperature of salt or ice in the process of solution cooling, and establish the empirical formula of freezing point. The empirical formula and the excess Gibbs free energy model are used to predict the freezing point and eutectic point of ternary system. The calculated values are in good agreement with the experimental data.
【作者单位】：新疆煤炭洁净转化与化工过程重点实验室新疆大学化学化工学院;
【基金】：国家自然科学基金项目(21166022)~~
【分类号】：O642.42

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