球状活性氧化铝的制备及表征

Preparation and Characterization of Spherical Activated Alumina

本文以Al_2(SO_4)_3和NaAlO_2溶液为原料,采用拟薄水铝石脱水法来制备球状活性氧化铝。文中研究了成胶pH值、成胶温度对拟薄水铝石原晶粒度、纯度、比表面积、孔容的影响;考察了分散工艺及热处理温度对活性氧化铝形貌、比表面积及孔容的影响。采用X射线衍射、比表面积测定仪、扫描电子显微镜等手段对实验制备的活性氧化铝予以表征。结果表明:控制成胶pH≈6,成胶温度60~80℃利于合成纯净的拟薄水铝石。采用喷雾干燥、400~600℃煅烧处理可以制备出球形度高、比表面积大,孔径分布集中的活性氧化铝粉体,满足多相催化裂解、反应尾气净化、"三废"污染物催化降解等领域的应用需求。

The spherical activated alumina was prepared by the method of pseudo-boehmite dehydration and using Al2（ SO4）3 and NaAlO2 as raw material. The effects of gelling pH and gelation temperature on the grain size,purity,specific surface area and pore volume of pseudo-boehmite were studied.The effects of dispersion process and heat treatment temperature on the morphology,specific surface area and pore volume of activated alumina were investigated. The prepared activated alumina was characterized by X-ray diffraction,specific surface area analyzer and scanning electron microscope. The results showed that high purity pseudo-boehmite could be synthesized under pH ≈ 6,and the temperature around 60 ～ 80℃. After spray drying and calcinated at 400 ～ 600℃,the activated alumina powder was produced with high sphericity,large surface area,and a relative concentrated pore size,which can meet the application requirement of the heterogeneous catalytic cracking,reaction tail gas purification and catalytic degradation of ＂ three wastes＂ pollutants.