Influence of Hydrothermal Treatment and Urea Modification on the Microstructure of Gibbsite
水热处理和尿素改性对三水铝石微观结构的影响

Gibbsite was modified by using urea as modifying agent via a hydrothermal method. Effects of the amount of urea and hydrothermal times on the microstructures were investigated. The results show that the slice-like boehmite microstructure can be obtained at 140  for 24 h when the molar ratio of urea to gibbsite is less than 6 : 1, while the global ammonium aluminum carbonate hydroxide (AACH) microstructure can be prepared at 140  for 24 h when the molar ratio was more than 8 : 1. The formation of AACH depends on the hydrothermal times. Aluminum hydroxide turned from gibbsite to the mixture of boehmite and AACH. Finally, AACH is synthesized. The morphology of aluminum hydroxide transformed from the block to the slice, and the global AACH trchitectures assembled by the lathes were obtained finally.