Preparation and characterization of cordierite-based ceramic foams with permeable property from asbestos tailings and coal fly ash

Abstract

The cordierite-based ceramic foams were successfully prepared by using asbestos tailings and coal fly ash (CFA) as main raw materials, without adding additional fluxing agent, and via the foaming agent method at a lower temperature. The influence of alumina content on the phase composition and structure of ceramic foams samples were investigated. At the same time, the influence of sintering temperature on phase evolution, physical and mechanical properties, microscopic morphology and water permeability were also studied. The results showed that the cordierite synthesized by the addition of 17.5% alumina had the better crystallinity. The addition of yellow sand could not only make up for the shortage of silicon sources in the raw materials, but also reduce the synthesis temperature of cordierite because it contained a certain amount of K+, Na+, Ca2+ and other fluxing components. Moreover, the bulk density, open porosity, water absorption, compressive strength and permeability coefficient of the cordierite-based ceramic foams prepared by the optimal formula S4 sintered at 1250 ℃ for 30 min were 0.77 g/cm3, 49.26%, 64.46%, 2.17 MPa and 0.71 mm/s, respectively. The product is expected to be used in the treatment of high-temperature exhaust gas and special waste water.