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

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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