Studies on Preparation and Mechanism of Nanometer Sized Aluminum Magnesium Hydroxide Material by Azeotropic Distillation Method

Aluminum magnesium hydroxide （AMH） hydrous sol was dehydrated by heterogeneous azeotropic distillation process of the systems consisting of the sol and benzene, n-butanol and propanoic acid, respectivily, according to the properties that those organisms with water may form azeotropes, and then vacuumly desiccated to obtain AMH solid materials. The preparation mechanism and properties of AMH solid materials were investigated. It was found that benzene and n-butanol may effectively prevent the hard agglomeration in the drying process to produce nanometer sized powder in diameter of 30～50nm, and the mechanism may be attributed to the decrease of capillary force amonge the particles during drying process because of the substitution of the organisms for water which didn’t affect the properties of crystal structure, thermogravimetric analysis and iso-electric point etc. However, the nanometer sized AMH powder can’t be prepared with propanoic acid although propanoic acid may chemically react with surface hydroxys of AMH particles which may apparently affect the properties of the product.