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低密度薄水铝石晶体的水热生长过程
引用本文:蔡卫权,李会泉,张懿.低密度薄水铝石晶体的水热生长过程[J].物理化学学报,2004,20(7):717-721.
作者姓名:蔡卫权  李会泉  张懿
作者单位: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
基金项目:国家高技术研究发展规划(863项目)(2001AA647010),国家自然科学基金(50234040)资助项目
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  
收稿时间:2003-12-19
修稿时间:2003年12月19

Hydrothermal Crystal Growth of Very Light Boehmite Products
Cai Wei-Quan Li Hui-Quan Zhang Yi.Hydrothermal Crystal Growth of Very Light Boehmite Products[J].Acta Physico-Chimica Sinica,2004,20(7):717-721.
Authors:Cai Wei-Quan Li Hui-Quan Zhang Yi
Institution: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
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.
Keywords:Very light boehmite  Hydrothermal synthesis  Uniform precipitation  Crystal growth  γ-Al2O3'  ')  γ-Al2O3" target="_blank">">γ-Al2O3
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