Abstract: Taking boehmite as precursor, alumina samples calcined under various temperatures were prepared, and their chemical properties and microstructures were characterized by XRD, FT-IR and HRTE to study the effect of calcination temperature on the microstructures and surface acidities of alumina samples. Results show that with the increase of calcination temperature (450-900 ℃), the acid amounts of alumina samples show a downward trend. When calcination temperature is in the range of 500-800 ℃, the obtained samples are γ-Al2O3 with microstructure of layer or lamellar fold; when calcination temperatures reach 700℃ and 800 ℃, the edges and corners of the laminar microstructure become obvious, yet the crystal sizes are basically unchanged; when calcination temperature reaches 900 ℃, partial δ-Al2O3 is observed, the sample morphology seems to be large flake structure. In these samples, Al2O3 (110) plane is the dominant crystal face, and a maximum exposure of Al2O3 (110) plane is observed with sample calcined at 700 ℃.

Key words: boehmite, alumina, calcination temperature, microstructure, surface acidity