Li^+,K^+//SO_4^(2-),B_4O_7^(2-)-H_2O交互四元体系273K介稳相平衡研究  

An Experimental Study on the Metastable Equilibrium in Quaternary System Li～+、K～+//SO_4～(2-)、B_4O_7～(2-)-H_2O at 273 K

作　　者：曾英[1] 林晓峰[1] 郑志远[1] 

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

出　　处：《高校化学工程学报》2009年第1期7-11,共5页Journal of Chemical Engineering of Chinese Universities

基　　金：国家自然科学基金(40673050)

摘　　要：采用等温蒸发法研究了四元体系Li+,K+//SO42-,B4O72-–H2O273K介稳相平衡,测定了该四元体系273K时介稳平衡液相组成及密度。根据实验数据绘制了相应的介稳相图、水图及密度组成图。研究发现:该体系介稳相图中有复盐KLiSO4形成,介稳相图中有3个共饱和点,7条单变线,平衡固相分别为Li2SO4·H2O,K2SO4,KLiSO4,LiBO2·8H2O和K2B4O7·4H2O。复盐KLiSO4和单盐Li2SO4·H2O有较小的结晶区,而LiBO2·8H2O、K2B4O7·4H2O和K2SO4的结晶区较大;平衡液相水含量随溶液K+浓度的减小而逐渐减少,在共饱和点E3处具有最小值;而平衡液相密度随溶液K+浓度的减小而逐渐增大,在共饱和点E3处具有最大值;该四元体系介稳平衡条件下Li2SO4的溶解度最高,有很强的盐析能力。Metastable equilibrium solubility and density of the solution in the quaternary system （Li^＋,K^＋//SO4^2-,B4O7^2- --H2O） at 273 k were determined by isothermal evaporation method. The metastable equilibrium phase diagram, the water-content diagram and the density-composition diagram were plotted. The metastable equilibrium phase diagram consists of three invariant points, seven univariant curves and five crystallization areas corresponding to single salts Li2SO4·H2O, K2SO4, LiBO2·8H20, K2B4O7·4H2O and double salt KLiSO4. The crystallization areas of double salt KLiSO4 and single salt Li2SO4·H2O are small, and that of salts K2SO4, LiBO2·8H2O and K2B4O7·4H2O are bigger. The density-composition diagram shows that the density of the equilibrium solution increases apparently with the decrease of potassium ion concentration and reaches its maximum value at invariant point E3. The water content of the equilibrium solution decreases with the decrease of its potassium ion concentration and reaches its minimum values at invariant point E3 Lithium sulfate has the highest solubility and strong salting-out effects on other coexisting salts.

关 键 词：介稳相平衡 硼酸盐 硫酸盐 溶解度 

分 类 号：O641.5[理学—物理化学]