物理化学学报 >> 2003, Vol. 19 >> Issue (02): 181-184.doi: 10.3866/PKU.WHXB20030220

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氯柱硼镁石在87 ℃水中的溶解及相转化动力学

李小平;刘志宏;高世扬;胡满成;夏树屏   

  1. 陕西师范大学化学与材料科学学院,西安　710062; 中国科学院青海盐湖所西安二部，西安　710043
  • 收稿日期:2002-06-18 修回日期:2002-09-20 发布日期:2003-02-15
  • 通讯作者: 刘志宏 E-mail:liuzh@snnu.edu.cn

The Kinetics of Dissolution and Phase Transformation of 2MgO•2 B2O3•MgCl2•14H2O in Water at 87 ℃

Li Xiao-Ping;Liu Zhi-Hong;Gao Shi-Yang;Hu Man-Cheng;Xia Shu-Ping;   

  1. College of Chemistry and Materials Science, Shaanxi Normal University, Xi’an　710062; Xi’an Branch， Institute of Salt Lakes，Chinese Academy of Sciences， Xi’an　710043
  • Received:2002-06-18 Revised:2002-09-20 Published:2003-02-15
  • Contact: Liu Zhi-Hong E-mail:liuzh@snnu.edu.cn

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摘要： 对氯柱硼镁石(2MgO•2B2O3•MgCl2•14H2O)在87 ℃水中的溶解转化进行了动力学考察.通过对不同时间取出液样的化学分析和不同阶段分离的固相IR和XRD鉴定表明：其高温区溶解转化不同于低温，氯柱硼镁石很快溶脱掉MgCl2，形成晶形的MgO•B2O3•4H2O中间产物，最终转化产物柱硼镁石（MgO•B2O3•3H2O）,是由MgO•B2O3•4H2O脱水后从溶液中大量析出的.提出了溶解及相转化机理,拟合出转化结晶动力学方程.

关键词: 氯柱硼镁石, 水合硼氧酸盐, 溶解动力学, 相转化, 反应机理

Abstract: The kinetics of dissolution and phase transformation of 2MgO•2B2O3•MgCl2•14H2O in water at 87 ℃ were studied. The results of liquid phases anlysized at a given time intervals and solid phases identified by IR and XRD show that 2MgO•2 B2O3•MgCl2•14H2O dissolved incongruently in water and the process was not the same at low temperature, a new crystal midproduct (MgO•B2O3•4H2O) was formed, the final solid phase was pinnoite (MgO•B2O3•3H2O). With the aid of Simplex Optimum Method and Runge-Kutta Digital Solution of differential equation system, the experimental data was fitted. The kinetic equation of the crystallization reaction was given and a mechanism of crystallization reaction was proposed.

Key words: Chloropinnoite(2MgO•, 2 B2O3•, MgCl2•, 14H2O), Hydrated borate, Dissolution kinetics, Phase transformation