高等学校化学学报 ›› 2002, Vol. 23 ›› Issue (4): 690.

• 研究论文 • 上一篇    下一篇

Na+,K+,Mg2+//Cl-,SO42--H2O五元体系15℃介稳相图研究

金作美, 周惠南, 王励生   

  1. 四川大学化工学院, 成都 610065
  • 收稿日期:2000-05-17 出版日期:2002-04-24 发布日期:2002-04-24
  • 通讯作者: 金作美(1931年出生),女,博士,教授,从事相平衡及非催化多相反应动力学研究.段朝玉,刘恒进行了部分化学分析工作.
  • 基金资助:

    国家自然科学基金(批准号;29070030)资助.

Studies on the Metastable Phase Equilibrium of Na+, K+,Mg+ //Cl-, SO42--H2O Quinary System at 15℃

JIN Zuo-Mei, ZHOU Hui-Nan, WANG Li-Sheng   

  1. College of Chemical Engineering, Sichuan University, Chengdu 610065, China
  • Received:2000-05-17 Online:2002-04-24 Published:2002-04-24

摘要: 得到Na+,K+,Mg2+//Cl-,SO42--H2O五元体系15℃时的介稳溶解度数据,绘制了该体系15℃的介稳相图,共有9个为氯化钠所饱和的结晶区域:氯化钾、硫酸钠、钾钠芒硝、软钾镁矾、白钠镁矾、光卤石、七水硫酸镁、六水硫酸镁和水氯镁石。所得15℃介稳相图和Van'tHoff稳定相图比较有较大区别;在15℃介稳相图中钾镁矾、钾盐镁矾以及五水硫酸镁和四水硫酸镁结晶区域消失,而软钾镁矾结晶区域显着扩大。比较作者所作该五元体系15℃,25℃及35℃介稳相图,发现软钾镁矾(包括钾镁矾)相区以25℃时最大,35℃时最小;随温度升高,钾钠芒硝结晶相区依次向KCl相区平行移动,导致KCl相区缩小,Na2SO4相区扩大;随温度升高相应点的钠含量和水含量依次减小。

关键词: 相平衡, 介稳相平衡, 海水型五元体系, 硫酸钾

Abstract: This paper presents the experimental date of metastable phase equilibrium of Na+, K+,Mg+ //Cl-, SO42--H2O quinary system at 15 ℃, from which the metastable phase diagram is drawn.lt con-sists of nine rigions of crystallization saturated with sodium chloride: potassium chloride, thenardite(Na2SO4), glasserite(3K2SO4·Na2SO4), schoenit(K2SO4·MgSO4·6H2O), astrankit(MgSO4·Na2SO4·4H2O), carnallite (KCl· MgCl2· 6H2O), epsomite (MgSO4·7H2O), hexahydrite (MgSO4·6H2O)and bischofit(MgCl2·6H2O).Alarge difference is found between the obtained metastable phase diagramat 15℃ and Van't Hoff's stable phase diagram at 25℃.The crystallization of leonite(K2SO4·MgSO4·4H2O), kainite(KCl·MgSO4·3H2O), magnesium sulfate quinhydrate(MgSO4·5H2O) and starkeyite(MgSO4·4H2O) disapear and the crystallization regions of schoenit greatly increased.Comparing themetastable phase diagram of Na+, K+, Mg2+ //Cl-, SO42- at 15 ℃ with the metastable phase dia-gram at 25℃ and 35℃ by the authors, it is found the crystallization region of schonite (includingleonite) at 25℃ is the largest, and at 35℃ is the smallest with the temperature rising from 15℃ to 35℃, the crystallization regions of glasserite parallelly moved toward KCl region, which made the KCl regiondecreasing and the Na2SO4 region increasing; with the temperature rising from 15℃, 25℃ to 35℃, thesodium containing and water containing decrease consequently.

Key words: Phase equilibrium, Metastable phase equilibrium, Sea-water type quinary system, Potassium sulfate

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