无机材料学报 ›› 2019, Vol. 34 ›› Issue (7): 781-785.DOI: 10.15541/jim20180508

• 研究论文 • 上一篇    下一篇

碱式氯化镁晶须制备纳米氧化镁热分解动力学研究

苟生莲1,2,3,乃学瑛1,肖剑飞1,叶俊伟4,董亚萍1,李武1,2()   

  1. 1. 中国科学院 青海盐湖研究所 中国科学院盐湖资源综合高效利用重点实验室, 西宁 810008
    2. 青海省盐湖资源化学重点实验室, 西宁 810008
    3. 中国科学院大学, 北京 100049
    4. 大连理工大学 化工学院, 大连 116024
  • 收稿日期:2018-10-26 修回日期:2019-01-08 出版日期:2019-07-20 网络出版日期:2019-06-26
  • 作者简介:苟生莲(1992-), 女, 硕士研究生. E-mail:goushenglian@163.com
  • 基金资助:
    国家自然科学基金柴达木盐湖化工科学研究联合基金(U1607101);青海省科技厅项目(2019-ZJ-7029)

Preparation and Thermal Decomposition of Basic Magnesium Chloride Whiskers

GOU Sheng-Lian1,2,3,NAI Xue-Ying1,XIAO Jian-Fei1,YE Jun-Wei4,DONG Ya-Ping1,LI Wu1,2()   

  1. 1. Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China
    2. Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province, Xining 810008, China
    3. University of Chinese Academy of Sciences, Beijing 100049, China
    4. School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
  • Received:2018-10-26 Revised:2019-01-08 Published:2019-07-20 Online:2019-06-26
  • Supported by:
    NSFC-Qaidam Salt Lake Chemical Science Research Joint Fund(U1607101);Qinghai Provincial Science and Technology Department Project(2019-ZJ-7029)

摘要:

采用水热法以氯化镁和氢氧化钙为原料制备了碱式氯化镁(BMC)晶须, 然后热解得到了纳米氧化镁。经透射电镜(TEM)和选区电子衍射(SAED)分析其粒径在20~40 nm之间, 暴露晶面族为{111}和{110}。通过热重差热分析(TG-DTA)、扫描电镜(SEM)、X射线衍射(XRD)以及红外光谱(FT-IR)分析确定了碱式氯化镁晶须热分解过程分四步进行, 前两步分别脱去两个结晶水, 第三步脱氯化氢, 最后脱羟基水。采用Satava法和微分法对BMC晶须的热分解机理和动力学进行了研究, 得出第一步反应热分解机理为随机成核与随后生长、第二步为二维扩散、第三步为相边界反应、第四步为一维相边界反应。

关键词: 碱式氯化镁, 纳米氧化镁, 热分解, 晶须, 水热法

Abstract:

Basic magnesium chloride (BMC) whiskers were prepared by hydrothermal method using magnesium chloride and calcium hydroxide as raw materials. Subsequently, nano-MgO was obtained by pyrolysis of the resulting whisker. Transmission electron microscopy (TEM) images showed that the diameter of nano-MgO was between 20 and 40 nm. The corresponding selected-area electron diffraction (SAED) pattern demonstrated the single-crystalline nature with the exposed plane of {111} and {110}. TG-DTG, SEM, XRD, and FT-IR analysis confirmed the four-step pyrolysis processes of BMC whisker. Results showed two molecules of crystal water lost during the first and second steps, respectively. Subsequently, two hydrogen chloride molecules were released in the third step. Finally, hydroxy water was dehydrated. The thermal decomposition kinetics of BMC whisker was studied by means of Satava and differential method. It indicates that the first step of the thermal decomposition of BMC whiskers is random nucleation and subsequent growth mechanism. The second step is two-dimensional diffusion. The third and the final steps are phase boundary reaction and one-dimensional phase boundary reaction mechanism, respectively.

Key words: basic magnesium chloride, nano magnesium oxide, thermal decomposition, whiskers, hydrothermal method

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