物理化学学报 >> 2004, Vol. 20 >> Issue (07): 717-721.doi: 10.3866/PKU.WHXB20040710

研究论文 上一篇    下一篇

低密度薄水铝石晶体的水热生长过程

蔡卫权;李会泉;张懿   

  1. 中国科学院过程工程研究所,绿色过程与工程重点实验室,北京 100080;中国科学院研究生院,北京 100039
  • 收稿日期:2003-12-19 修回日期:2004-03-04 发布日期:2004-07-15
  • 通讯作者: 蔡卫权 E-mail:wqcai@home.ipe.ac.cn

Hydrothrmal Crystal Growth of Very Light Boehmite products

Cai Wei-Quan;Li Hui-Quan;Zhang Yi   

  1. Institute of Process Engineering, the Key Laboratory of Green Process Engineering, Chinese Academy of Sciences, Beijing 100080;Graduate School of the Chinese Academy of Sciences, Beijing 100039
  • Received:2003-12-19 Revised:2004-03-04 Published:2004-07-15
  • Contact: Cai Wei-Quan E-mail:wqcai@home.ipe.ac.cn

摘要: 对Al2(SO4)3-CO(NH2)2-H2O体系在[Al3+]=0.2 mol•L-1、[CO(NH2)2]:[Al3+]=2∶1和反应2 h的水热条件下,不同反应温度的晶体生长过程进行了研究,得到呈多孔、针状团簇体状的微米级低密度薄水铝石晶体.采用ICP-AES、XRD、FT-IR、SEM、BET和粒径分布等手段对反应液和产物进行了分析和表征.结果表明,140 ℃时氢氧化铝凝胶或无定形粉体的析出已大部分完成,温度升高到180 ℃后,产物的结晶度变好,堆密度从117.2 kg•m-3相应增加到158.2 kg•m-3,比表面也从75.3 m2•g-1增加到88.3 m2•g-1,但平均粒径有所下降.晶体前驱体在550 ℃焙烧2 h后完全转化为形貌相似并且比表面增加的γ-Al2O3.

关键词: 低密度薄水铝石, 水热法, 均匀沉淀, 晶体生长, γ-Al2O3

Abstract: The hydrothermal precipitation in the Al2(SO4)3-CO(NH2)2-H2O system under the conditions of [Al3+]=0.2 mol•L-1,[CO(NH2)2]:[Al3+]=2:1 and 2 h at different temperatures has been studied. Very light boehmite powders in the form of porous agglomeration of several micron size covered with needle clusters are obtained at above 140 ℃.The reaction solution and the products are characterized by ICP-AES, XRD, FT-IR, SEM, BET and particle size distribution. The precipitation of aluminum hydroxide gel or amorphous powder is almost completed at 140 ℃. With the reaction temperature raised to 180 ℃, crystallinity of the products, whose tap density varies among 117.2~158.2 kg•m-3,becomes more perfect and the specific surface area increases from 75.3 m2•g-1 to 88.3 m2•g-1 as well. However, the average diameter decreases moderately. The γ-Al2O3 powders formed by calcination of aforementioned boehmites at 550 ℃ for 2 h have the same shape and higher specific surface area compared with their corresponding precursors.

Key words: Very light boehmite, Hydrothermal synthesis, Uniform precipitation,  Crystal growth, γ-Al2O3