三元体系LiBr-Li2SO4-H2O 298 K相平衡  

Phase equilibrium in ternary system LiBr-LiSO-HO at 298 K

作　　者：张学平 周小玲 范绍奇 王洲 郑海 许茂勤 ZHANG Xue-ping;ZHOU Xiao-ling;FAN Shao-qi;WANG Zhou;ZHENG Hai;XU Mao-qin(College of Chemistry&Chemical Engineering,Sichuan University of Arts and Science,Dazhou 635000,Sichuan Province,China)

机构地区：[1]四川文理学院化学化工学院,四川达州635000

出　　处：《化学工程》2020年第7期59-61,78,共4页Chemical Engineering(China)

基　　金：国家级大学生创新创业训练计划项目(201910644006);四川文理学院科研项目(2019PT008Y);四川文理学院大学生科研项目(X2019Z039)。

摘　　要：为了获取地下卤水中的锂盐的溶解和析盐规律,进一步指导开发宝贵的液态锂资源,文中采用等温溶解平衡法研究了三元体系LiBr-Li2SO4-H2O在298 K时的固液稳定相平衡关系,测定了平衡溶液的饱和溶解度和密度,并根据饱和液相组成、湿固相组成和对应的平衡固相绘制了等温溶解度图和密度-组成图。结果表明:三元体系在298 K时的相图为简单共饱和型相图,平衡固相中无复盐和固溶体形成;该体系的相图由一个共饱点E,2条单变量溶解度曲线AE和BE,2个单盐结晶区组成,其中结晶区分别对应于二水溴化锂和一水硫酸锂;在三元体系中,溴化锂对硫酸锂有明显的盐析作用,且一水硫酸锂的结晶区远大于二水溴化锂。平衡液相对应的饱和固相由湿渣法和XRD确定。In this work,the stable phase equilibrium relationship between solid and liquid phase,and the saturated solubilities and densities of equilibrium solution in the ternary system lithium brimide-lithium sulfate-water were measured at 298 K by using an isothermal dissolution equilibrium method in order to obtain the dissolution and salt precipitation rules of lithium salt in underground brine,and further guide the exploitation of precious liquid lithium resources.Based on the determined composition of equilibrium liquid phaseand wet solid phase,and the corresponding equilibrium solid phase,the phase diagrams and density diagrams of the system were plotted.According to the phase diagram,univariant solubility curves and solid crystalline regions were discussed.The results show that the ternary system is simple without any double salt or solid solution formed in the phase diagram.The phase diagram of the ternary system is constituted of one invariant point,two univariant solubility curves and two solid crystalline phase regions corresponding to LiBr·2 H2O and Li2SO4·H2O.In the ternary system,lithium bromide has a significant salting out effect on lithium sulfate,and the crystalline area of lithium sulfate monohydrate is much larger than that of lithium bromide dihydrate.The solid phase was determined by the wet residues method combined with XRD.

关 键 词：相平衡 溶解度 溴化锂 硫酸锂 

分 类 号：O642[理学—物理化学]