物理化学学报 >> 2002, Vol. 18 >> Issue (12): 1116-1119.doi: 10.3866/PKU.WHXB20021212

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2MgO•2B2O3•MgCl2•14H2O-MgCl2-H2O体系30 ℃相平衡

刘志宏;胡满成;高世扬   

  1. 陕西师范大学化学与材料科学学院, 西安 710062
  • 收稿日期:2002-04-26 修回日期:2002-07-02 发布日期:2002-12-15
  • 通讯作者: 高世扬 E-mail:l-zhihong@163.net

Phase Equilibrium of 2MgO•2B2O3•MgCl2•14H2O-MgCl2-H2O System at 30 ℃

Liu Zhi-Hong;Hu Man-Cheng;Gao Shi-Yang   

  1. School of Chemistry and Materials Science, Shaanxi Normal University, Xi’an 710062
  • Received:2002-04-26 Revised:2002-07-02 Published:2002-12-15
  • Contact: Gao Shi-Yang E-mail:l-zhihong@163.net

摘要: 用相平衡方法研究2MgO•2B2O3•MgCl2•14H2O 在30 ℃不同质量分数MgCl2 水溶液中的溶解转化产物及其溶解度. 结果表明, 该复盐在MgCl2的质量分数0~2%浓度范围, 发生不同步溶解并转化为多水硼镁石(2MgO•3B2O3•15H2O); 在MgCl2的质量分数2%~13.8%浓度范围, 转化为柱硼镁石(MgO•B2O3•3H2O), 这一结果比文献报导的该硼酸盐的形成温度低了13 ℃,为盐湖硼酸镁矿物柱硼镁石形成的解释提供了物理化学依据; 而在MgCl2质量分数大于13.8%时同步溶解,不发生转化. 提出了溶解相转化反应机理.

关键词: 氯柱硼镁石, 氯化镁, 相平衡

Abstract: The phase equilibrium of 2MgO•2B2O3•MgCl2•14H2O-MgCl2-H2O system at 30 ℃ has been studied. The experimental results showed that the phase transformation product was inderite(2MgO•3B2O3•15H2O) when the mass fraction of MgCl2 is in the range 0 to 2%, pinnate(MgO•B2O3•3H2O) in the range 2% to 13.8%, demonstrating a great reduction in the temperature of formation of MgO•B2O3•3H2O and providing some physico-chemical basis in explaining the formation of pinnoite mineral in the salt lakes. When the mass fraction of MgCl2 was higher than 13.8%, the chloropinnoite dissolved congruently and did not transform. The mechanisms of the dissolution and phase transformation have been proposed.

Key words: Chloropinnoite, Magnesium chloride, Phase equilibrium