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Chem. J. Chinese Universities ›› 2003, Vol. 24 ›› Issue (2): 189.

• Preface •     Next Articles

Phase Relation of 2MgO·2B2O3·MgCl2·14H2O-7.8%H3BO3-H2O System at Various Temperatures

LIU Zhi-Hong1,2, HU Man-Cheng1, GAO Shi-Yang1,2   

  1. 1. School of Chemistry and Materials Science, Shaanxi Normal University, Xi′an 710062, China;
    2. School of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
  • Received:2002-06-05 Online:2003-02-24 Published:2003-02-24

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Abstract: The phase relation of 2MgO·2B2O3·MgCl2·14H20-7.8%H3BO3-H20 system at various temperatures has been studied by FTIR spectroscopy, XRD, TG, as well as chemical analyses. The phase transformation product is MgO·2B2O3·9H20 at 0-22 ℃, MgO·2B2O3·7.5 H20 at 22-68 ℃, MgO·2B2O3·7H20 at 68-95 ℃, MgO·2B2O3·5H20 at 95-98.8 ℃, MgO·B2O3·3H20 at 100-110 ℃, 2MgO·B2O3·2H20 at 110-120 ℃, 2MgO·B2O3·1.5H20 at 120-170 ℃, and 2MgO·B2O3·H20 at 170-200 ℃, respectively. The mechanisms of dissolution and phase transformation have been proposed and discussed.

Key words: Chloropinnoite, Mg-borates, Phase relation

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