Acta Phys. -Chim. Sin. ›› 2005, Vol. 21 ›› Issue (10): 1161-1163.doi: 10.3866/PKU.WHXB20051020

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Study on the Composition and Mechanism of Precipitated Solid Phases from MgO•3B2O3-18%MgSO4-H2O Supersaturated Solution

YAN Chang-ling; LU Yan; ZHOU Jian-guo   

  1. College of Chemistry and Environmental Science, Henan Normal University, Xinxiang Henan 453007; Department of Chemistry, Lanzhou University, Lanzhou 730000
  • Received:2005-01-21 Revised:2005-04-05 Published:2005-10-15
  • Contact: LU Yan

Abstract: The supersaturated solution of MgO•3B2O3-18%MgSO4-H2O was prepared and reacted under hydrothermal conditions at 150 ℃. The solid phases precipitated from the supersaturated solution at different times were identified by chemical analysis, XRD, FT-IR. The results show that the reaction process is unique. The precipitated solid phases of 1 to 5 days were mainly szaibelyite and they gradually dissolved with reaction proceeded. At the same time new solid phases also appeared which composed of MgSO4•H2O and MgSO4•1.25H2O. The latter was an intermediate with less amount. The former was final product. Based on these results the crystallization mechanism of szaibelyite under the hydrothermal conditions and discussed the effects of hydrothermal temperature on the composition of precipitated solid phases was proposed.

Key words: Hydrothermal temperature, Supersaturated solution, Mg- borate, Crystallization mechanism