中文摘要：

应用等温溶解平衡法研究了三元体系Li2B4O7-K2B4O7-H2O 273 K时的稳定相平衡,测定了该体系饱和溶液的溶解度和密度。通过实验数据和固相组成分别绘制了三元体系Li2B4O7-K2B4O7-H2O 273 K时的相图以及相应的密度-组成图。该体系的稳定相图包含一个共饱点,对应的平衡固相为Li2B4O7·3H2O和K2B4O7·4H2O,共饱点液相组成（质量分数）为Li2B4O72.27%,K2B4O79.80%,两条单变量曲线,两个固相结晶区,分别对应Li2B4O7·3H2O和K2B4O7·4H2O。实验结果表明：体系属于简单共饱型,没有形成复盐和固溶体;Li2B4O7·3H2O和K2B4O7·4H2O之间存在相互盐溶作用;在共饱点处,饱和溶液的密度达到最大。同时,对该三元体系在273,288,298,348 K不同温度时的稳定相图作了对比分析和讨论,发现该体系两种盐在不同温度下有相同的结晶形式。

英文摘要：

The stable phase equilibrium in Li2B4O7-K2B4O7-H2O ternary system at 273 K was studied using isothermal solubility equilibrium method, and the solubilities of salts and densities of the saturated solution were determined. According to the experimental data and the composition of solid phase, the phase diagram of the Li2BnOT-K2BnO7-H2O ternary system at 273 K and the corresponding density- composition diagram were plotted, respectively. The stable phase diagram included by an invariant point, corresponding to Li2B4O7·3H2O and K2B4O7·4H2O, the compositions （mass fraction） of liquid phase were 2.27% for Li2B4O7and 9.80% for K2B4O7 in the invariant point, two univariant solubility curves, two solid phase crystalline regions, corresponding to Li2B4O7 · 3H2O and K2B4O7·4H2O, respectively. The results show that the ternary system belongs to simple eosaturated type and there are neither double salts nor solid solutions, there are salt-dissolution effect in Li2B4O7 · 3H2O and K2B4O7·4H2O. In addition, the density of saturated solution reaches maximized in the invariant point. At the same time, a comparative analysis and discussion were made for the stable phase diagrams of the system at 273, 288, 298, 348 K. It was found that the two salts had the same crystal forms at different temperatures in the system.