Preparation and performance of fly ash porous ceramics for filtration

Porous ceramics were prepared from fly ash by adding a pore-making agent. Some effects of the amount of the poremaking agent and sintering temperature on the properties of the porous ceramics were studied. The properties of specimens were characterized by pressure mercury analyzer, X-ray diffraction (XRD), and field emission scanning electron microscopy (SEM). The results show that with the pore-making agent increasing, the porosity and water absorption increase, but the bending strength and density decrease. Increasing the sintering temperature can improve the bending strength of the porous ceramics. However, main phases in the porous ceramics are similar at different sintering temperatures. As the sintering temperature is more than 1175℃, the porosity and gas permeability decrease significantly. When the amount of the pore-making agent is 35% and the sintering temperature is 1175℃, the fly ash porous ceramics for filtration have high bending strength, advanced porosity and high specific surface area.