三元水盐体系冰点和共晶点的测定、相图表达及计算  

Determination, graphics expression and calculation of freezing point and eutectic point in ternary salt-water system

作　　者：刘福云[1] 黄雪莉[1] 黄文婷[1] 王雪莹[1] 潘毅[1] 

机构地区：[1]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,新疆乌鲁木齐830046

出　　处：《化工学报》2017年第9期3336-3342,共7页CIESC Journal

基　　金：国家自然科学基金项目(21166022)~~

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。In this paper, aiming at ternary salt-water systems of Na^＋//Cl^-,NO3^--H2O、Na^＋//Cl^-,SO4^2--H2O and Na^＋,K^＋//Cl^--H2O, the freezing points, eutectic points and the crystallization regularities of salts were investigated; the three-dimensional phase diagrams of temperature-composition of the ternary systems were plotted according to experimental data. The results were as following： the relationships among the freezing point, eutectic point, phases and the compositions of solution for the ternary system can be expressed by triangular prism. In the three ternary systems, there were no double salts at the eutectic point temperature, and there was an eutectic point with two salts and ice, three eutectic lines with single salt and ice or two salts, a crystallization zone with ice and two single salt. The three-dimensional phase diagram of temperature-composition of solution can be used to describe the relationships among the crystalline regions, freezing points or eutectic points and the compositions of liquids for the ternary salt-water systems visually, and to determine the precipitation processes of salts or ice as cooling solution. Three empirical formulas about freezing points were established. The empirical formulas of freezing point and the excess Gibbs free energy model were used to predict the freezing point and eutectic point of the ternary systems, which turned out that the calculated values were in good agreement with the experimental values.

关 键 词：水盐体系 共晶点 冰点 相图 计算 

分 类 号：O642.54[理学—物理化学]