焙烧温度对氧化铝物化性质及微观结构的影响

Effect of Calcination Temperature on Physical and Chemical Properties and Microstructure of Alumina

以拟薄水铝石为前驱体,经不同温度焙烧制备氧化铝,利用X-射线衍射、N2-物理吸附、扫描电镜、透射电镜等技术对其物化性质及微观结构进行表征,系统研究了焙烧温度对氧化铝物化性质及微观结构的影响规律。结果表明:在低温(500～800℃)条件下焙烧时,氧化铝的比表面积、孔容随着焙烧温度的升高缓慢降低,平均孔径缓慢增大,分别467 m2/g,1.05 cm3/g,8.9 nm,变为429 m2/g,1.03 cm3/g,9.6 nm。所得氧化铝的微观结构为层状或褶皱的片层结构,表面形貌为由球状微小颗粒堆积的疏松、多孔形貌;在高温(900～1 300℃)条件下焙烧时,氧化铝的比表面积、孔容随着焙烧温度的升高迅速降低,平均孔径迅速增大,分别275 m2/g,0.99 cm3/g,14.5 nm,变为13 m2/g,0.05 cm3/g,28.9 nm。所得氧化铝的微观结构为块状或棒状结构,表面形貌为由较大球状颗粒堆积的致密块状形貌。

Taking pseudoboehmite as precursor,then alumina was prepared under different calcination temperatures,its physical and chemical property and microstructure were characterized by X-ray diffraction,N2-physisorption,scanning electron microscope,transmission electron microscope and so on.Effect of calcination temperature on physical and chemical properties and microstructure of alumina was studied.The results show that： when calcination temperature is 500~800 ℃,along with increasing of the calcination temperature,specific surface area and pore volume of alumina decrease slowly,but average pore size increases slowly,they change from 467 m2/g,1.05 cm3/g,8.9 nm into 429 m2/g,1.03 cm3/g,9.6nm,respectively.Microstructure of alumina is layer or lamellar fold,surface morphology is loose and porous by accumulating of small global grain.When calcination temperature is 900~1 300 ℃,specific surface area and pore volume of alumina decrease rapidly,average pore size increases rapidly,they change from 275 m2/g,0.99 cm3/g,14.5 nm into 13 m2/g,0.05 cm3/g,28.9 nm,respectively.Microstructure of alumina is clubbed or nubby structure.Surface morphology is compact nubby congeries by accumulating of bigger global grain.