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新疆盐湖资源丰富,冬季寒冷漫长,已有研究表明利用冬季冷能可以实现卤水浓淡分离。本文采用等温溶解平衡法针对新疆含硝酸盐卤水开发过程中涉及的Na~+,K~+//Cl~-,SO_4~(2-),NO_3~-H_2O及Na~+,K~+//Cl~-,NO_3~-H_2O体系273.15K下的相平衡关系进行了研究。通过查找文献及实验获得两个体系各盐的溶解度及溶液密度,并绘制相图。研究表明,上述四元体系的干盐相图有2个零变量点、5条单变量溶解度曲线、4个单盐结晶区分别对应于NaNO_3、NaCl、KNO_3和KCl,与该体系在298.15K下的相图相比,硝酸钾结晶区扩大很多;上述五元体系干盐相图(NaCl饱和)有2个零变量点、5条单变量溶解度曲线、4个两盐结晶区分别对应于NaCl+NaNO_3,NaCl+Na_2SO_4·10H_2O,NaCl+KNO_3,NaCl+KCl,与该体系298.15K下的相图相比,复盐钾芒硝和钠硝矾结晶区消失,芒硝结晶区扩大,相图大为简化。
Xinjiang Salt Lake is rich in resources and has a long and cold winter. Studies have shown that brine can be separated by using cold winter energy. In this paper, isothermal dissolution equilibrium method was used to study the effects of Na +, K + / Cl ~ -, SO_4 ~ (2 -), NO_3 ~ -H_2O and Na ~ +, K ~ + / / Cl ~ -, NO_3 ~ -H_2O system at 273.15K phase equilibrium was studied. By searching literature and experimenting, the solubility and solution density of each salt in the two systems were obtained and the phase diagrams were drawn. The results show that the dry salt phase diagram of the quaternary system has two zero-point and five univariate solubility curves, and the four single-salt crystallization zones correspond to NaNO_3, NaCl, KNO_3 and KCl, respectively. Compared with the system at 298.15K Compared with the phase diagram of potassium nitrate, the crystallization range of potassium nitrate is greatly expanded. There are two zero-point points and five univariate solubility curves in the five-component dry salt phase diagram (NaCl saturation) NaNO_3, NaCl + Na_2SO_4 · 10H_2O, NaCl + KNO_3, NaCl + KCl. Compared with the phase diagram at 298.15K in the system, the crystal regions of the double salt glauberite and sodium nitrous vanadium disappeared and the crystal regions of the mirabilite expanded. The phase diagram was greatly simplified .