Preparation of high performance mullite ceramics from high-aluminum fly ash by an effective method

Abstract

High performance mullite ceramics were prepared from high-aluminum fly ash without any extra materials via a series of steps. The original fly ash was pretreated with alkali and acid to adjust the chemical composition. Furthermore, the physical properties and phase transformation of the as-prepared samples at different sintering temperatures were systematically investigated. The results showed that by pretreated process, Al2O3 content can reach up to 65.35wt%, and most of the impurities were removed. The beneficiated sintering sample exhibited a mullite content of 88.33%, an apparent porosity of 1.20%, a bulk density of 2.78g/cm3 and a compressive strength of 169MPa, which was comparable with previous reports. All results indicate that high-aluminum fly ash, pretreated by an effective and feasible method, is suitable to prepare high performance mullite ceramics.