Li^(+),K^(+),Ca^(2+)∥Cl^(-)-H_(2)O四元体系298.2 K固液相平衡研究  

Study on solid-liquid phase equilibrium of Li^(+),K^(+),Ca^(2+)∥Cl^(-)-H_(2)O quaternary system at 298.2 K

作　　者：于旭东[1,3] 黎静 任思颖 罗军 曾英 YU Xudong;LI Jing;REN Siying;LUO Jun;ZENG Ying(College of Materials and Chemistry&Chemical Engineering,Chengdu University of Technology,Chengdu 610059,China;Qinghai Salt Lake Industrial Co.,Ltd.,Golmud 816000,China;Tianfu Yongxing Laboratory,Chengdu 610213,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]青海盐湖工业股份有限公司,青海格尔木816000 [3]天府永兴实验室,四川成都610213

出　　处：《无机盐工业》2025年第3期30-35,42,共7页Inorganic Chemicals Industry

基　　金：四川省科技计划资助项目(2023ZYD0036);天府永兴实验室有组织科研项目(2023KJGG13)。

摘　　要：四川盆地深藏卤水蕴含丰富的锂、钾资源,极具开发利用价值,但共存离子作用关系复杂。为获取深藏卤水中锂钾钙共存氯化物体系在298.2 K时各盐的结晶规律,采用等温溶解平衡法开展了四元体系Li^(+),K^(+),Ca^(2+)∥Cl^(-)-H_(2)O 298.2 K固液相平衡研究,测定了溶解度、平衡液相密度,采用X射线粉晶衍射法分析了平衡固相组成,并绘制了相应的相图。结果表明:298.2 K时,该四元体系有锂钙复盐(LiCl·CaCl_(2)·5H_(2)O)生成,为复杂四元体系;氯化钙结晶形式受共存氯化锂的影响同时存在CaCl_(2)·6H_(2)O和CaCl_(2)·4H_(2)O。对应的固液平衡相图由3个四元共饱点(E_(1)和E_(2)为不相称共饱点、E_(3)为相称共饱点)、7条单变量曲线和5个结晶区组成(结晶区面积由大到小为KCl、LiCl·H_(2)O、CaCl_(2)·4H_(2)O、LiCl·CaCl_(2)·5H_(2)O、CaCl_(2)·6H_(2)O)。Deep brine in Sichuan basin is abundant in lithium and potassium resources,which has significant development potential,however,the interactions among the coexisting ions are complex.To obtain the crystallization law of each salt in the coexistence chloride system of lithium,potassium,and calcium,the solid-liquid phase equilibria of Li^(+),K^(+),Ca^(2+)∥Cl^(-)-H_(2)O quaternary system at 298.2 K was investigated by using isothermal dissolution method.The solubilities and densities of the solution were determined,meanwhile the solid phase of the quaternary invariant point was identified by X-ray diffraction.The phase diagram was constructed by using the measured data.The results showed that the system was a complex quaternary system with the double salt LiCl·CaCl_(2)·5H_(2)O formed,and the crystalline form of calcium chloride was influenced by the coexisting lithium chloride,with both CaCl_(2)·6H_(2)O and CaCl_(2)·4H_(2)O forms present simultaneously.The corresponding solid-liquid phase diagram consisted of 3 quaternary invariant points(points E_(1) and E_(2) were incommensurate type,E_(3) belonged to commensurate type),7 univariate curves and 5 crystallization regions,the area of crystallization regions was decreased in the order of KCl,LiCl·H_(2)O,CaCl_(2)·4H_(2)O,LiCl·CaCl_(2)·5H_(2)O,CaCl_(2)·6H_(2)O.

关 键 词：相平衡 相图 溶解度 深藏卤水 复盐 

分 类 号：TQ131.1[化学工程—无机化工]