四元体系LiCl+MgCl_(2)+CaCl_(2)+H_(2)O 323.2 K相平衡研究及计算  

Phase equilibria and calculation of quaternary system LiCl+MgCl_(2)+CaCl_(2)+H_(2)O at 323.2 K

作　　者：陈科 杜理 曾英[1,2] 任思颖 于旭东[1,2] CHEN Ke;DU Li;ZENG Ying;REN Siying;YU Xudong(College of Materials and Chemistry&Chemical Engineering,Chengdu University of Technology,Chengdu 610059,Sichuan,China;Mineral Resources Chemistry Key Laboratory of Sichuan Higher Education Institution,Chengdu 610059,Sichuan,China)

机构地区：[1]成都理工大学材料与化学化工学院,四川成都610059 [2]矿产资源化学四川省高校重点实验室,四川成都610059

出　　处：《化工学报》2023年第5期1896-1903,共8页CIESC Journal

基　　金：国家自然科学基金项目(U21A2017)。

摘　　要：采用等温溶解平衡法开展了323.2 K四元体系LiCl+MgCl_(2)+CaCl_(2)+H_(2)O的固液相平衡研究,测定了平衡液相组成及密度、折射率,并绘制了相应的相图。研究发现:323.2 K时,该体系有复盐LiCl·MgCl_(2)·7H_(2)O和2MgCl_(2)·CaCl_(2)·12H_(2)O生成,属于复杂四元体系,其相图包含3个共饱点,7条单变量曲线,5个结晶区(MgCl_(2)·6H_(2)O、LiCl·H_(2)O、CaCl_(2)·2H_(2)O、LiCl·MgCl_(2)·7H_(2)O、2MgCl_(2)·CaCl_(2)·12H_(2)O)。对比298.2 K下该四元体系的相图,发现随着温度升高,氯化钙从CaCl_(2)·6H_(2)O、CaCl_(2)·4H_(2)O转化成CaCl_(2)·2H_(2)O,LiCl·MgCl_(2)·7H_(2)O和MgCl_(2)·6H_(2)O结晶区减小,LiCl·H_(2)O和2MgCl_(2)·CaCl_(2)·12H_(2)O结晶区增大,表明温度升高有利于LiCl·H_(2)O和2MgCl_(2)·CaCl_(2)·12H_(2)O析出。采用PSC模型对该四元体系进行了溶解度计算,计算结果与实验结果基本吻合。The solid-liquid phase equilibria of the quaternary system LiCl+MgCl_(2)+CaCl_(2)+H_(2)O at 323.2 K were studied by the isothermal dissolution method.The density,refractive index and composition of liquid phase were determined experimentally.The phase diagram of the quaternary system at 323.2 K was plotted.The results show that there are two double salts LiCl·MgCl_(2)·7H_(2)O and 2MgCl_(2)·CaCl_(2)·12H_(2)O formed in the quaternary system,belonging to a complex system.The phase diagram of this quaternary system consists of three invariant points,seven univariate curves,five crystallization fields corresponding to MgCl_(2)·6H_(2)O,LiCl·H_(2)O,CaCl_(2)·2H_(2)O,LiCl·MgCl_(2)·7H_(2)O,2MgCl_(2)·CaCl_(2)·12H_(2)O.Comparing the phase diagram of the quaternary system at 323.2 K and 298.2 K,it has found that with the increase of temperature,calcium chloride is converted from CaCl_(2)·6H_(2)O and CaCl_(2)·4H_(2)O to CaCl_(2)·2H_(2)O,the crystallization fields of LiCl·MgCl_(2)·7H_(2)O and MgCl_(2)·6H_(2)O decrease and the crystallization fields of LiCl·H_(2)O and 2MgCl_(2)·CaCl_(2)·12H_(2)O increase,which indicates that increasing temperature is beneficial to the precipitation of LiCl·H_(2)O and 2MgCl_(2)·CaCl_(2)·12H_(2)O.The solubility of the quaternary system was calculated by using the PSC model,and the calculated results were basically consistent with the experimental results.

关 键 词：相平衡 水溶液 溶解性 热力学性质 锂盐 

分 类 号：O642.4[理学—物理化学]