Synthesis, characterization and sintering behaviour of indialite ceramic from fly ash

Indialite ceramic was prepared using fly ash and magnesium carbonate powder as precursors. The effects of sintering aids LiOH · H2O and TiO2 on its crystallization and morphology evolution were studied as well. X-ray diffraction results indicated that the formation of indialite was achieved by solid-state sintering reactions at 1200 °C for 4 h. With increasing amounts of LiOH · H2O, the viscosity decreased and β-spodumene, spinel phases started to develop at the expense of indialite. Scanning electron microscopy observations revealed that the surface of the sintered samples became smoother with higher porosity losses and grain size reduction. As the TiO2 contents increased from 4 to 10%, dauphine-twinned quartz and rutile were formed by simultaneously consuming indialite. In this process, the viscosity showed no significant changes.