Phase Diagram of the Quaternary System KCl–MgCl₂–NH₄Cl–H₂O at t = 60.00 °C and Their Application

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• 作者：Jing-Xue Wu ; Guo-Cheng Zhang ; Bin Zhao ; Shuo Wang…
• 关键词：Potassium chloride ; Magnesium chloride ; Ammonium chloride ; Solubility ; Phase diagram ; Ammonium carnallite
• 刊名：Journal of Solution Chemistry
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：46
• 期：1
• 页码：58-69
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Physical Chemistry; Industrial Chemistry/Chemical Engineering; Geochemistry; Oceanography; Inorganic Chemistry; Condensed Matter Physics;
• 出版者：Springer US
• ISSN：1572-8927
• 卷排序：46

文摘

Based on the requirement for the comprehensive exploitation and utilization of the salt lake resources magnesium chloride and potassium chloride, a new technology to produce KCl and ammonium carnallite (NH₄Cl·MgCl₂·6H₂O) by using NH₄Cl as salting-out agent to separate carnallite is proposed. The solubilities of quaternary system KCl–MgCl₂–NH₄Cl–H₂O were measured by the isothermal method at t = 60.00 °C and the corresponding phase diagram was plotted and analyzed. The analysis of this phase diagram shows that there are seven saturation points and eight regions of crystallization. These eight regions of crystallization represent salts corresponding to KCl, NH₄Cl, MgCl₂·6H₂O, (K_1−n(NH₄)_n)Cl, ((NH₄)_nK_1−n)Cl, (K_1−n(NH₄)_n)Cl·MgCl₂·6H₂O, KCl·MgCl₂·6H₂O and NH₄Cl·MgCl₂·6H₂O. According to the phase diagram analysis and calculations, ammonium carnallite (NH₄Cl·MgCl₂·6H₂O) and KCl can be obtained using carnallite as raw materials and ammonium chloride as salting-out agent at t = 60.00 °C. The new technology shows the advantages of being easy to operate and having low energy consumption. The research on this quaternary phase diagram is the foundation for reasonable development of carnallite resources and comprehensive utilization of the salt lake brines.