The Heat Treatment Process Of Hydrous Alumina And Caracteristics Of Nanometer Al2o3

By means of IR, XRD TG-DTA and TEM, the characteristics and the thermal treatment processes of hydrous alumina as the hydrolysate of aluminium alkoxide were examined, and the influence of various thermal treatment processes on the granular characteristics of nano-Al2O3 particles was also investigated. The results showed that hydrous alumina was amorphous diaspore [AlO(OH)l retaining abundant adsorptive and structural crystal water. Parts of AlO(OH) were converted into amorphous gamma-Al2O3 after calcination at 300 degrees C. Calcination temperature, holding time and cooling mode exerted effects on the crystal shape, size and morphology of the alumina particles. The influence of the calcination temperature is the most significant, followed by cooling mode. In contrast, the influence of holding time was the lowest. Spheric or fibrillar alpha- or gamma-Al2O3 with the size of 3 similar to 5 nm, 3 similar to 5 nm, 5 similar to 10 nm, 10 similar to 15 nm and 50 similar to 100 nm might be produced under the thermal treatment conditions of 750 degrees C for 3 h, 800 degrees C for 4 h, 900 degrees C for 4 h, 950 degrees C for 4 h and 1000 degrees C for 4 h, respectively.