Phase Equilibria for the Aqueous Reciprocal Quaternary System Rb+, Mg2+//Cl鈥?/sup>, Borate鈥揌2O at 348 K

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• 作者：Qinghong Yin ; Pengtao Mu ; Qi Tan ; Xudong Yu ; Zhongquan Li ; Ying Zeng
• 刊名：Journal of Chemical & Engineering Data
• 出版年：2014
• 出版时间：July 10, 2014
• 年：2014
• 卷：59
• 期：7
• 页码：2235-2241
• 全文大小：371K
• ISSN：1520-5134

文摘

Phase equilibria for the reciprocal quaternary system containing rubidium, magnesium, chloride, and borate in aqueous solution at 348 K was investigated by isothermal dissolution method. The compositions, densities, and refractive indices of the solution at equilibrium were measured experimentally. The space phase diagram, the planar projection diagram, the water content diagram, and the diagrams of the physicochemical properties (densities and refractive indices) vs composition were constructed using the measured data. Results indicate that the quaternary system is a complex type along with the double salt rubidium carnallite (RbCl路MgCl₂路6H₂O) formed at 348 K. The planar projection diagram consists of three invariant points, seven univariant curves and five crystallization zones corresponding to four single salts rubidium pentaborate tetrahydrate (RbB₅O₆(OH)₄路2H₂O), hungchaoite (MgB₄O₅(OH)₄路7H₂O), rubidium chloride(RbCl), bischofite(MgCl₂路6H₂O), and a double salt of rubidium carnallite (RbCl路MgCl₂路6H₂O). With a view to the crystallization zones, the crystallization zone of salt RbB₅O₆(OH)₄路2H₂O occupies the largest part, meaning rubidium borate can be more easily separated from solution than the other coexisting salts in this system at 348 K. The water content and physicochemical properties of the equilibrium solution corresponding the univariant curve EH₃ change obviously with the increase of J(Mg²⁺), whereas the water content and physicochemical properties change only slightly on the other univariant curves.