Abstract Based on the requirement of the new technology for producing ammonium carnallite and NaCl via the solution left after the preparation of potassium salt as raw materials, the solubilities of the quaternary system NaCl-MgCl2-NH4Cl-H2O and ternary subsystem NaCl-MgCl2-H2O at 333.15 K were measured using the isothermal dissolution method, and the corresponding phase diagrams were plotted. The phase diagram of the ternary system consists of three fields of crystallization, which correspond to NaCl, MgCl2·6H2O and their co-existing fields respectively. There are four fields of crystallization in the quaternary system, which correspond to MgCl2·6H2O, NH4Cl, NaCl and the double salt MgCl2·NH4Cl·6H2O respectively. By analyzing and calculating the phase diagrams, a technological route was proposed, which indicated that the Na-Mg resources were fully utilized. The extended Pitzer model was applied to the phase equilibrium calculation and the results showed that the calculated data were consistent with experimental values well.

中文翻译：

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333.15 K下四元系NaCl-MgCl2-NH4Cl-H2O的相图及其应用

摘要 基于钾盐制备后剩余溶液制备铵光卤石和氯化钠新工艺的要求，四元体系NaCl-MgCl2-NH4Cl-H2O和三元子系统NaCl-MgCl2-H2O的溶解度在 333.15 K 下使用等温溶解法测量，并绘制了相应的相图。三元体系的相图由三个结晶场组成，分别对应于NaCl、MgCl2·6H2O及其共存场。四元系有四个结晶场，分别对应于MgCl2·6H2O、NH4Cl、NaCl和复盐MgCl2·NH4Cl·6H2O。通过对相图的分析计算，提出了技术路线，说明钠镁资源得到充分利用。将扩展的Pitzer模型应用于相平衡计算，结果表明计算数据与实验值吻合较好。