Solid鈥揕iquid Equilibrium in the Aqueous System Containing the Borates of Potassium, Rubidium, and Magnesium at 348 K

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• 作者：Hao Shi ; Shan Feng ; Jiangle Zhang ; Yujuan Zhang ; Xudong Yu ; Ying Zeng
• 刊名：Journal of Chemical & Engineering Data
• 出版年：2015
• 出版时间：November 12, 2015
• 年：2015
• 卷：60
• 期：11
• 页码：3224-3228
• 全文大小：260K
• ISSN：1520-5134

文摘

The stable phase equilibrium and phase diagram of the quaternary system K⁺, Rb⁺, Mg²⁺ // borate路H₂O at 348 K were determined by isothermal dissolution method. The densities, refractive indices, and solubility values of the equilibrated solution in the quaternary system were measured. The crystalloid forms of the solid phase of invariant point were identified by X-ray diffraction method. The stable phase diagram, water content diagram, and the diagrams of the densities/refractive indices versus composition were plotted based on the measured data. Results show that this quaternary system at 348 K without double salt or solid solution formed belongs to a simple eutectic type. The invariant point E saturated with three salts corresponding to potassium tetraborate tetrahydrate (K₂B₄O₅(OH)₄路2H₂O), rubidium pentaborate tetrahydrate (RbB₅O₆(OH)₄路2H₂O), and hungchaoite (MgB₄O₅(OH)₄路7H₂O). The crystallization field of RbB₅O₆(OH)₄路2H₂O is the maximum, meaning that it has the smallest solubility among the coexisting salts. On the solubility curves AE (cosaturated with salts MgB₄O₅(OH)₄路7H₂O and RbB₅O₆(OH)₄路2H₂O) and BE (cosaturated with salts K₂B₄O₅(OH)₄路2H₂O and RbB₅O₆(OH)₄路2H₂O), the water content decreases, the densities and refractive indices increase with the increase of J(K₂B₄O₇); on the curve CE (cosaturated with salts MgB₄O₅(OH)₄路7H₂O and K₂B₄O₅(OH)₄路2H₂O), the water content and the densities increase, the refractive indices decrease with the increase of J(K₂B₄O₇).