Preparation of Mullite Ceramics with Fly Ash and Clay by Pickling Process

Mullite ceramics were fabricated with fly ash, clay, and Al2O3 as raw materials. The effects of Al2O3 content, the sintering temperature and the pickling process on the crystalline phases, sintering characteristics and microstructures were studied. With more addition amount of Al2O3 and higher sintering temperature, the peak intensity of the mullite crystalline phase increased. By pickling process, mullite instead of anorthite became the main phase with little corundum. Moreover, the required sintering temperature had reduced to 1300 degrees C and the Al2O3 content also decreased to 30 wt%. The pickling process also enlarged the sintering range of the green bodies.