中文摘要：

采用等温溶解平衡法研究298．16K时四元体系K^＋，Mg^2＋／／Cl^-，NO3^-H2O的液固相平衡关系，测定了溶解度数据，并绘制出平衡相图。研究表明，在298．16K时，该体系相图有5个单盐结晶区、6条单变量溶解度曲线和3个零变量点。5个单盐结晶区分别对应于KNO3、KCl、Mg（NO3）2·6H2O、MgCl2·6H2O和复盐KCl·MgCl2·6H2O，其中KNO3的结晶区最大，MgCl1·6H2O的结晶区最小。

英文摘要：

Solubilities in the quaternary system K^＋,Mg^2＋//Cl^-,NO3^-H2O were investigated by isothermal method at 298.16K. Based on the solubility＇ s data obtained, the phase diagram of the system was plotted. The dry salt phase diagram of the sysiem K^＋,Mg^2＋//Cl^-,NO3^-H2O consists of five crystallization regions corresponding to KNO3, KCl, Mg（NO3 ）2 ·6H2 O, MgCl2 ·6H2O and KCl· MgCl2 ·6H2O. The respective crystallization areas are being separated from each other by six univariant curves which intersect in three invariant points. The crystallization area of KNO3 is the largest, while the one of MgCl2 6H2O is the smallest.