Considering the significance of fundamental phase equilibrium data in resource exploitation from salt lake brines, the solid–liquid phase equilibria of the ternary system (KBO₂ + K₂SO₄ + H₂O) at 288.15, 308.15 K, and 0.1 MPa were investigated using the isothermal dissolution method. Along this line, the solubilities and physicochemical properties of densities were experimentally determined. Based on the experimental data, phase diagrams and the related physicochemical property diagrams against composition were plotted. It was found that there are one invariant point, two univariate solubility curves, and two crystalline regions corresponding to potassium metaborate hydrate (KBO₂·1.33H₂O) and arcanite (K₂SO₄) in the ternary phase diagrams at 288.15 and 308.15 K. In addition, they belong to the hydrate type I and neither double salt nor solid solution was formed. The distributive behaviors of density against the concentration of KBO₂ in the equilibrium solution at two temperatures were similar. Moreover, the theoretical values of density were calculated, which were found to be consistent with the experimental values, further demonstrating the accuracy and reliability of this work.

中文翻译：

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三元体系（KBO ₂ + K ₂ SO ₄ + H ₂ O）在288.15、308.15 K和0.1 MPa时的固液平衡

考虑到基本相平衡数据在盐湖盐水资源开发中的重要性，研究了三元体系（KBO ₂ + K ₂ SO ₄ + H ₂ O）在288.15、308.15 K和0.1 MPa时的固液相平衡。使用等温溶解法。沿着这条线，通过实验确定了密度的溶解度和理化性质。根据实验数据，绘制了相图和有关成分的相关理化性质图。发现存在一个不变点，两个单变量溶解度曲线，和两个对应于偏硼酸钾水合物（KBO ₂ ·1.33H _2）的结晶区域。O）和奥（K ₂ SO ₄）在三元相图在288.15和308.15 K.另外，它们属于I和既不复盐也没有固体溶液形成的水合物的类型。在两个温度下，密度对平衡溶液中KBO ₂浓度的分布行为是相似的。此外，计算了密度的理论值，发现其与实验值一致，进一步证明了这项工作的准确性和可靠性。