Stable Phase Equilibrium of Aqueous Quaternary System Li+, K+, Mg2+//Borate鈥揌2O at 348 K

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• 作者：Qi Tan ; Ying Zeng ; Pengtao Mu ; Xudong Yu ; Yujuan Zhang
• 刊名：Journal of Chemical & Engineering Data
• 出版年：2014
• 出版时间：December 11, 2014
• 年：2014
• 卷：59
• 期：12
• 页码：4173-4178
• 全文大小：323K
• ISSN：1520-5134

文摘

The solubility values and physicochemical properties such as densities, refractive indices, and pH values of the equilibrium solution in the quaternary system Li⁺, K⁺, Mg²⁺//borate鈥揌₂O at 348 K were measured by isothermal dissolution method. The phase diagram, water content diagram, and the diagrams of the physicochemical properties versus composition were constructed using the measured data. Results show that this quaternary system at 348 K is of a simple type, no double salt or solid solution formed. The stable phase diagram of this quaternary system consists of one invariant point, three univariant curves, and three crystalline phase areas. The invariant point saturated with three salts corresponding to lithium tetraborate trihydrate (Li₂B₄O₇路3H₂O), potassium tetraborate tetrahydrate (K₂B₄O₇路4H₂O), and hungchaoite (MgB₄O₇路9H₂O). The crystallization field of MgB₄O₇路9H₂O is the maximum, meaning that the salt magnesium borate has the smallest solubility among the coexisting salts. Comparisons between the stable phase diagrams at 288 K and 348 K show that the crystallization zones of MgB₄O₇路9H₂O decreased at 348 K, while the crystallization zones of K₂B₄O₇路4H₂O and Li₂B₄O₇路3H₂O both enlarged at 348 K. On the univariant curve CE, the water contents decrease with the increase of J(K₂B₄O₇); the densities and refractive indices both increase with the increase of J(K₂B₄O₇) and reach the maximum at invariant point E.