三元体系偏硼酸锂–碳酸锂–水288.15K相平衡研究

Phase Equilibria for the Ternary System of Lithium Metaborate- Lithium Carbonate-Water at 288.15K

用等温溶解平衡法研究三元体系Li BO2–Li2CO3–H2,O在288.15,K时稳定相平衡及其溶液物化性质(密度、折光率和p H),绘制该三元体系的稳定相图和平衡溶液物化性质–组成图.研究结果表明:该三元体系有一个共饱点(Li BO2·8H2,O+Li2CO3)、两条单变量溶解度曲线和两个单盐结晶区,两个结晶区分别对应为Li BO2·8H2O和Li2CO3,其中Li2CO3结晶区大而Li BO2·8H2O结晶区较小.该体系属水合物I型,既没有发生脱水现象,也没有复盐和固溶体产生.采用经验公式计算该体系平衡溶液的密度和折光率,计算值与实验值吻合较好.

The solubilities and physicochemical properties（density,pH value,and refractive index）of the ternary system LiBO2-Li2CO3-H2O at 288.15,K were investigated with the method of isothermal dissolution equilibrium. According to the experimental results of the ternary system,the stable phase diagram and the diagrams of physicochemical properties versus composition were plotted. In the phase diagrams of the ternary system,there was one eutectic point corresponding to lithium metaborate octahydrate and lithium carbonate（LiBO2·8H2O＋Li2CO3）,two isotherm dissolution curves,and two crystalliza-tion regions corresponding to LiBO2·8H2O and Li2CO3,respectively. This system belongs to hydrate type I,and neither de-hydration phenomenon nor double salts and solid solutions were found. The calculated values of density and refractive index using empirical equations of the ternary system are in good agreement with the experimental values. .