【摘要】 采用等温溶解平衡法对四元体系KCl-MgCl₂-SrCl₂-H₂O在288 K时进行固液相平衡研究,测定平衡液相中各盐的溶解度,使用X射线粉晶衍射法鉴定相应的平衡固相,获得共饱点处平衡固相的XRD图谱。根据实验所得的数据绘制四元体系的平衡相图及局部放大图和水含量图。研究结果表明:在288 K时该体系的稳定相图由2个共饱点、5条单变量曲线和4个结晶区组成,4个结晶区分别对应KCl, SrCl₂·6H₂O,MgCl₂·6H₂O和KCl·MgCl₂·6H₂O,其中KCl的结晶区最大,其次为SrCl₂·6H₂O,而前两者结晶区比MgCl₂·6H₂O大得多,表明MgCl₂·6H₂O对KCl和SrCl₂·6H₂O有强的盐析作用。该四元体系有一种复盐（光卤石KCl·MgCl₂·6H₂O）生成。该四元体系相图的研究结果可用于指导卤水体系中氯化钾和氯化锶的分离提取工艺。更多还原

【Abstract】 The solid-liquid equilibria of quaternary system KCl-MgCl₂-SrCl₂-H₂O at 288 K was studied by isothermal solution equilibrium method. The solubilities of each salt in the corresponding equilibrium liquid phase were measured, and the X-ray powder diffraction was carried out to identify the equilibrium solids on the invariant point, and the XRD equilibrium solid in invariant point was obtained. The corresponding equilibrium phase diagram, partial enlargement and water content diagram of the quaternary system were drawn based on the experimental data. The results show that the stable phase diagram of this system at 288 K consists of two invariant points, five univariate curves and four crystallization regions. The four crystalline regions correspond to KCl, SrCl₂·6 H₂O, MgCl₂·6 H₂O, KCl·MgCl₂·6 H₂O, respectively. Among them, the crystallization area of KCl is the largest, followed by SrCl₂·6 H₂O, and the crystallization areas of the former two are much larger than MgCl₂·6 H₂O, indicating that MgCl₂·6 H₂O has a strong salting-out effect on KCl and SrCl₂·6 H₂O. The quaternary system has a double salt（carnallite KCl·MgCl₂·6 H₂O） forms, which is a complex water-salt system. The research results of the phase diagram of this quaternary system can be used to guide the separation and extraction process of potassium chloride and strontium chloride in the brine system.更多还原