MgO•3B2O3-18%MgSO4-H2O过饱和溶液析出固相组成和机理研究

针对青藏高原盐湖卤水析盐过程的特点, 模拟合成MgO?3B₂O_3-18%MgSO_4-H₂O过饱和溶液, 在150 ℃水热条件下对析出固相进行研究. 用化学分析方法、X射线衍射、红外光谱进行物相鉴定. 提出了可能的结晶反应机理, 分析了水热温度对析出物相的影响及MgSO₄对硼酸镁盐的盐溶效应随水热温度的变化.

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

The supersaturated solution of MgO?3B₂O_3-18%MgSO_4-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.