三元体系Li_2SO_4-LiBO_2-H_2O在288.15K时介稳相平衡  

Metastable equilibria of Li_2SO_4-LiBO_2-H_2O ternary system at 288.15 K

作　　者：赵美玲[1] 王士强[1] 韩徐年 郭亚飞[1] 邓天龙[1] 

机构地区：[1]天津科技大学海洋科学与工程学院天津市海洋资源与化学重点实验室,天津300457

出　　处：《化学工程》2015年第3期37-40,45,共5页Chemical Engineering(China)

基　　金：国家自然科学基金资助项目(21106103;21276194;21306136);天津市应用基础与前沿技术研究计划项目(12JCQNJC03400);高等学校博士学科点专项科研基金(20111208120003)

摘　　要：采用等温蒸发法,测定了三元体系Li2SO4-LiBO2-H2O在288.15 K时的溶解度和液相的物化性质(密度、折光率、p H值)。结果表明:该体系有2条单变量曲线;1个共饱点(Li2SO4·H2O+LiBO2·8H2O),对应的液相组成(质量分数)为:Li2SO424.47%,LiBO21.20%;2个单盐结晶区,分别是:Li2SO4·H2O和Li BO2·8H2O。其中,LiBO2·8H2O的结晶区较大,原因是Li2SO4对Li BO2有强烈的盐析作用。与该体系的稳定相图相比,盐的结晶形式没有变化,但是15℃介稳相图中Li2SO4·H2O结晶区面积增大,而LiBO2·8H2O结晶区面积减小。该三元体系为水合物Ⅰ型,没有固溶体及复盐生成。平衡液相的物化性质随溶液中硫酸锂质量分数的增大而呈现规律性的变化,密度和折光率在共饱点处有最大值。用经验公式对密度和折光率进行了关联,计算值和实验值吻合较好。Using the method of isothermal evaporation, the solubility and the physicochemieal property such as density, refractive index and pH value for Li2SO4-LiBO2-H2O ternary system at 288. 15 K were measured. According to the experimental results, there were two univariant curves; one eutectie for （Li2SO4 · H2O ＋ LiBO2 · 8H2O） , and the compositions of Li2SO4 and LiBO2 in the liquid phase with mass fraction of 24.47% , 1.20% , respectively; and two crystallization fields corresponding to two single salts Li2SO4 ~ H2O and LiBO2 ~ 8H2O. The area of crystallized zone of LiBO2· 8H2O was much larger than that of Li/SO4 ~ H/O. The reason was that the salt of Li2SO4 had a strong salting-out effect to LiBO2. Compared with stable phase diagram of this ternary system at 288.15 K, it shows that the solid phase numbers and exist minerals are the same, and the crystallized region of Li2SO4 ~ H2O is increased while that of LiBO2 ~ 8H2O is decreased obviously. This system belongs to a hydrate I , and neither double salt nor solid solution is found. In addition, the solution physicochemical properties changed regularly with the increasing of Li2SO4 mass fraction; density and refractive index reach the maximum value at the invariant point in the system. The calculated values of density and refractive index using empirical equations are in good agreement with the experimental values.

关 键 词：介稳相平衡 等温蒸发 硫酸锂 偏硼酸锂 

分 类 号：O642.42[理学—物理化学]