Hot water hydrolysis - controlled precipitation and the preparation of nano alumina, spherical α alumina powder

摘要

Aluminium metal has been hydrolyzed in hot aqueous - glycerol media composed of various volume % of glycerol. After hydrolysis in the aqueous - glycerol media, the product i.e., precipitate was aged at room temperature and the ageing medium was diluted periodically. The precipitation and ageing media has influenced the phase composition and morphology of the hydroxides significantly. The morphology of the hydroxide and a alumina powders were examined using TEM and SEM respectively. It has been found that the crystallinity and morphology of hydroxide influenced the morphology ofαalumina, importantly the hydroxide powder prepared using 25% aqueous - glycerol medium, upon calcination yielded sphericalαlumina powder.