Fabrication and characterization of anorthite-mullite-corundum porous ceramics from construction waste

In this work, anorthite-mullite-corundum porous ceramics were prepared from construction waste and Al2O3 powders by adding AlF3 and MoO3 as mineralizer and crystallization catalyst, respectively. The effects of the sintering temperature and time on open porosity, mechanical properties, pore size distribution, microstructure, and phase composition were characterized in detail. The results showed that the formation of the mullite whiskers and the properties of the anorthite-mullite-corundum porous ceramics depended more on the sintering temperature than the holding time. By co-adding 12 wt% AlF3 and 4 wt% MoO3, mullite whiskers were successfully obtained at sintering temperatures upon 1350 °C for 1 h. Furthermore, the resultant specimens exhibited excellent properties, including open porosity of 66.1±0.7%, biaxial flexural strength of 23.8±0.9 MPa, and average pore size of 1.32 µm (the corresponding cumulative volume percent was 37.29%).