298.2 K四元体系MgCl2-SrCl2-AlCl3-H2O相平衡实验及溶解度计算  

Measurements and simulation for aqueous quaternary system MgCl2-SrCl2-AlCl3-H2O at 298.2K

作　　者：郑秋风 罗军 陈帅 陈念粗 于旭东[1,2] 曾英 ZHENG Qiufeng;LUO Jun;CHEN Shuai;CHEN Niancu;YU Xudong;ZENG Ying(College of Materials and Chemistry&Chemical Engineering,Chengdu University of Technology,Chengdu 610059,Sichuan,China;Center of Panxi Strategic Mineral Resources Multi-Purpose Utilization,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]四川省攀西战略矿产资源综合利用协同创新中心,四川成都610059

出　　处：《化工学报》2020年第12期5443-5451,共9页CIESC Journal

基　　金：四川省科技厅应用基础面上项目(2017JY0191);四川省教育厅自然科学类重点项目(16ZA0083)。

摘　　要：采用等温溶解平衡法研究了298.2 K四元体系MgCl2-SrCl2-AlCl3-H2O的相平衡关系,测定了该体系的溶解度和平衡溶液的密度、折射率。根据实验数据,分别绘制了298.2 K该四元体系的空间立体图、相图、水图、密度-组成图和折射率-组成图。研究发现:298.2K下,四元体系MgCl2-SrCl2-AlCl3-H2O无复盐或固溶体生成,稳定相图由2个共饱点、5条单变量曲线和4个结晶区组成。四个结晶区分别为MgCl2·6H2O、SrCl2·6H2O、SrCl2·2H2O和AlCl3·6H2O,其中SrCl2·6H2O结晶区最大,SrCl2·2H2O结晶区最小,说明SrCl2·6H2O更容易结晶析出。平衡液相的密度和折射率随着J(MgCl2)的变化呈规律性变化。采用Pitzer模型进行了298.2 K四元体系MgCl2-SrCl2-AlCl3-H2O溶解度计算,对比发现,计算结果与实验结果基本吻合。Solid-liquid equilibria of the aqueous quaternary system MgCl2-SrCl2-AlCl3-H2O at 298.2K was studied by using the isothermal dissolution equilibrium method.The solubility,density,and refractive index of the aqueous quaternary system were measured.The corresponding space diagram,stable phase diagram,water content diagram,and the diagrams of density vs composition,refractive index vs composition were constructed based on the experimental data.The results show that there is no double that salt or solid solution was formed in the quaternary system.The stable phase diagram of the quaternary system MgCl2-SrCl2-AlCl3-H2O at 298.2 K consists of two invariant points,five isothermal dissolution curves,and four crystallization regions.The four crystallization regions correspond to four single hydrate salts magnesium chloride hexahydrate(MgCl2·6H2O),strontium chloride hexahydrate(SrCl2·6H2O),strontium chloride dihydrate(SrCl2·2H2O),and aluminum chloride hexahydrate(AlCl3·6H2O).With a view to the crystallization regions,the crystallization region of salt SrCl2·2H2O is the smallest,while the crystallization region of salt SrCl2·6H2O is the largest,meaning SrCl2·6H2O can be more easily separated from solution than other coexisting salts in this system at 298.2 K.The densities and refractive indices of the solution at equilibrium change regularly with the change of J(MgCl2)of the solution.The Pitzer model is used to calculate the solubility of the 298.2 K quaternary system MgCl2-SrCl2-AlCl3-H2O.The comparison found that the calculated results are basically consistent with the experimental results.

关 键 词：相平衡 热力学性质 溶解性 水合物 PITZER模型 

分 类 号：O642.4[理学—物理化学]