Solubility Phase Diagram of the Quaternary System Li+, Mg2+//Cl鈥?/sup>, SO42鈥?/sup>鈥揌2O at 298.15 K: Experimental Redetermination and Model Simula

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• 作者：Hongxia Li ; Dewen Zeng ; Yan Yao ; Xia Yin ; Dongdong Li ; Haijun Han ; Hongyan Zhou
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：May 7, 2014
• 年：2014
• 卷：53
• 期：18
• 页码：7579-7590
• 全文大小：597K
• 年卷期：v.53,no.18(May 7, 2014)
• ISSN：1520-5045

文摘

Solubility isotherms for the ternary system MgCl₂鈥揗gSO₄鈥揌₂O and the quaternary reciprocal system Li⁺, Mg²⁺//Cl^{鈥?/sup>, SO₄2鈥?/sup>鈥揌₂O were determined at 298.15 K by an isothermal dissolution method. In the ternary phase diagram, there are six solubility branches corresponding to the solid phases MgSO₄路nH₂O_(s) (n = 7, 6, 5, 4, 1) and MgCl₂路6H₂O_(s). In the quaternary equilibrium phase diagram, there are 16 solubility co-saturated lines corresponding to the solid phases MgSO₄路nH₂O_(s) (n = 7, 6, 5, 4, 1), MgCl₂路6H₂O_(s), Li₂SO₄路H₂O_(s), LiCl路MgCl₂路7H₂O_(s), and LiCl路H₂O_(s). This report describes for the first time that the equilibrium solid phases MgSO₄路H₂O_(s) and MgSO₄路4H₂O_(s) have been found to exist in this quaternary system. However, the phase field of MgSO₄路H₂O_(s) overlaps with the phase fields of MgSO₄路4H₂O_(s) and MgSO₄路5H₂O_(s), which indicates that MgSO₄路4H₂O_(s) and MgSO₄路5H₂O_(s) are metastable phases; MgSO₄路H₂O_(s) is a relatively more stable phase in both the ternary and quaternary systems. A Pitzer鈥揝imonson鈥揅legg thermodynamic model was used to simulate the properties of the sub-binary and subternary systems and to predict the solubility phase diagram of the quaternary system. The results of the modeling are in reasonable agreement with the experimental data.}