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化学学报
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化学学报 ›› 2010, Vol. 68 ›› Issue (17): 1699-1706. 上一篇    下一篇

研究论文

不同浓度的MgCl2和NaCl溶液对H3BO3介稳区宽度的影响

孟庆芬1，董亚萍*,1，孔凡志1,2，冯海涛1,2，李武1   

  1. (1中国科学院青海盐湖研究所 西宁 810008)
    (2中国科学院研究生院 北京 100049)
  • 投稿日期:2010-01-13 修回日期:2010-04-23 发布日期:2010-05-10
  • 通讯作者: 董亚萍 E-mail:qqmqf@sina.com
  • 基金资助:

    察尔汗盐湖开发过程稀散元素资源动态研究

Study on the Metastable Zone Property of Boric Acid in Different Concentrations of MgCl2 and NaCl Solutions

Meng Qingfen1 Dong Yaping*,1 Kong Fanzhi1,2 Feng Haitao1,2 Li Wu1   

  1. (1 Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008)
    (2 Graduate School of Chinese Academy of Sciences, Beijng 100049)
  • Received:2010-01-13 Revised:2010-04-23 Published:2010-05-10
  • Contact: DONG YaPing E-mail:qqmqf@sina.com

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利用激光测量装置测定了H3BO3在不同浓度的MgCl2和NaCl溶液中的溶解度和超溶解度, 得到了H3BO3在上述溶液中的介稳区宽度, 推算出H3BO3的成核级数m．实验结果表明: H3BO3的介稳区宽度在高温区狭窄而在低温区较宽; 与H3BO3在纯水中的溶解度相比, MgCl2和NaCl均能降低H3BO3在水中的溶解度, 尤以MgCl2为甚, 且随着二者浓度的升高, 介稳区先变窄最后变宽. MgCl2对H3BO3的表观成核级数影响较大, NaCl对其影响较小; 在MgCl2中等浓度和NaCl较低浓度下, 成核级数小, 有利于晶体的生长, 在该区域可获得较大粒度的晶粒.

关键词: MgCl2, NaCl, H3BO3, 介稳区, 激光

The solubility and ultra solubility of boric acid (H3BO3) in solutions with different concentrations of MgCl2 and NaCl were determined by using laser detection technique．In addition, the metastable zones of H3BO3 in these solutions were obtained. Furthermore, the nuclear progression m of H3BO3 was calculated. Our experimental results showed that the stable area of H3BO3 was narrow at high temperature, and wide at low temperature. Compared to the solubility of H3BO3 only in water, the solubility of H3BO3 decreased with increasing amount of MgCl2 and NaCl in water and was more affected by MgCl2 than by NaCl. The metastable zone of H3BO3 first became narrower and then wider with increasing concentrations of MgCl2 and NaCl．The metastable zone of H3BO3 in MgCl2 and NaCl solutions was narrower than in the H3BO3-H2O system. The effect of MgCl2 on apparent nucleus progression of H3BO3 was much more than that of NaCl. The crystal grew better in medium concentration of MgCl2 and low concentration of NaCl because of the smaller nuclear progression．Therefore, crystal with greater granularity can be obtained in such buffer condition．

Key words: MgCl2, NaCl, H3BO3, metastable zone, laser