From Kaolins (with Addition of Al_2O_3) to Mullite Composite Nanocrystals: Experiments and Analysis

摘要

Natural and raw high-silica kaolins are firstly processed into fine kaolin powders with oxidation-reduction bleaching method before mixed with Al_2O_3 powders and then baked to produce mullite composite oxides at temperature between 1050-1150°C. The mullite composite oxides are further made into composite mullite nanocrystals by using open-system hydrothermal crystallization method under normal pressure. Analysis of the final products show that the mullite nanocrystals are texturally homogenous at an average size around 80-100 nm and have high thermal stability.