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MgCl2·6H2O热分解机理的研究

黄琼珠, 路贵民, 汪 瑾, 于建国   

  1. 华东理工大学 化学工程联合国家重点实验室, 上海 200237
  • 收稿日期:2009-07-10 修回日期:2009-08-30 出版日期:2010-03-20 网络出版日期:2010-03-20

Thermal Decomposition Mechanism of MgCl 2·6H2O

HUANG Qiong-Zhu, LU Gui-Min, WANG Jin, YU Jian-Guo   

  1. StateKey Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
  • Received:2009-07-10 Revised:2009-08-30 Published:2010-03-20 Online:2010-03-20

摘要: 利用综合热分析仪、电阻炉煅烧、X射线衍射、扫描电镜、能谱分析和化学分析, 研究了MgCl2·6H2O的热分解机理及中间产物形貌. 研究发现: MgCl2·6H2O热分解过程分为六步, 在69℃时生成MgCl2·4H2O, 129℃时生成MgCl2·2H2O, 167℃时生成MgCl2·nH2O(1≤n≤2)和MgOHCl, 203℃时MgCl2·nH2O(1≤n≤2)水解与脱水同时进行生成Mg(OH)Cl·0.3H2O, 235℃时Mg(OH)Cl·0.3H2O脱水转变为MgOHCl, 415℃时MgOHCl直接分解生成MgO. MgOHCl颗粒形状不规则, 为多孔结构, Mg(OH)Cl·0.3H2O颗粒表面平整.

关键词: MgCl2·6H2O, Mg(OH)Cl·0.3H2O, 脱水, 水解, 热分解

Abstract: The thermal decomposition mechanism and the intermediate morphology of MgCl2·6H2O before and after calcination by a resistance furnace, were studied using integrated thermal analysis, X-ray diffraction, scanning electron microscope, energy dispersive X-ray spectrum and chemical analysis. The results showed that there were six steps in the thermal decomposition of MgCl2·6H2O, producing MgCl2·4H2O at 69℃, MgCl2·2H2O at 129℃, MgCl2·nH2O(1≤n≤2) and MgOHCl at 167℃, and the MgCl2·nH2O(1≤n≤2) converted to Mg(OH)Cl·0.3H2O with dehydration and hydrolysis simultaneously at 203℃, Mg(OH)Cl·0.3H2O dehydrated to MgOHCl at 235℃, MgOHCl directly converted to MgO at 415℃. The MgOHCl particle was irregular with porous structure, while Mg(OH)Cl·0.3H2O particle had relatively flat surface.

Key words: MgCl2·6H2O, Mg(OH)Cl·0.3H2O, dehydration, hydrolysis, thermal decomposition

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