Realizable recycling of coal fly ash from solid waste for the fabrication of porous Al2TiO5-Mullite composite ceramic

Abstract

As the environment deteriorates, recycling of solid waste has become increasingly important. This study aimed to optimize the use of the Fe2O3, SiO2, and CaO components in coal fly ash and to convert coal fly ash into stable porous Al2TiO5-mullite (AT–M) composite ceramic by sintering with AlOOH and TiO2 additives at high temperatures. The phase composition, microstructure, apparent porosity, corrosion resistance, and mechanical properties of porous AT–M composite ceramics were systematically investigated. Results indicated that the sintered samples exhibited pore size distributions within the 0.16-2.9 μm, apparent porosities of approximately 52.8%, and flexural strength of 29.6 MPa. Corrosion resistance data revealed quality losses in the aqueous NaOH and H2SO4 solutions for 10 hours at 0.42% and 2.19%, respectively. After corrosion for 8 hours, the average flexural strength of the samples remained at 21.6 ± 0.53 and 20.84 ± 0.6 MPa, respectively. These findings show that these porous AT–M ceramics may provide enhanced corrosion resistance under alkaline conditions. The porous AT–M composite ceramics may fabricate high-performance composite membrane supports for the high temperature flue gas filtration.