Effect of V_2O_5 on the properties of mullite ceramics synthesized from high-aluminum fly ash and bauxite

摘要

In this communication, high-strength mullite ceramics was prepared from bauxite and high-aluminum fly ash that is a by-product of coal combustion in thermal power plants. The effects of the doping V_2O_5 on the bulk density, apparent porosity, bending strength and microstructure of mullite ceramics were studied in detail. It was indicated that 5-10 mol% V_2O_5 reduced the sintering temperature by 50 C. The apparent porosity and water absorption of the mullite ceramics decreased with increasing V_2O_5 content. Mullite ceramics with bending strength as high as 108 MPa were obtained at 1500 ℃ with the addition of 10mol%V_2O_5. X-ray diffraction analysis suggested that the prepared ceramics was mainly in phase of mullite, and scanning electron microscope images confirmed that it mostly existed in the shape of a long parallelepiped. This research may provide a new method in utilizing the vast resources of fly-ash waste from power plants in the production of low-cost mullite-based engineering materials.