High-performance mullite fibrous ceramic filter enhanced by composite sintering aids for dust-laden gas filtration

Fibrous ceramic filter is one of the promising candidates for high-temperature gas cleaning but is constrained seriously by its mechanical strength. In this work, we successfully prepared a mullite fibrous ceramic filter (MFCF) with high bending strength reinforced by a composite sintering aid of kaolin and feldspar. The bending strength of the MFCF can reach up to 13.1 MPa that was much higher than those reported in the literature. The mullite phase was formed on the neck during the sintering process and greatly enhanced the bending strength as can be characterized by X-ray diffraction (XRD) patterns and three-point bending test. These ceramic filters at the optimized fabrication conditions have a porosity of 61.8%, an average pore size of 14.8 μm, and nitrogen permeance of above 673 m³·m⁻²·h⁻¹·kPa⁻¹, respectively. Moreover, the mullite-fiber-based filters exhibited satisfactory thermal shock resistance and corrosion resistance after experiencing thermal fatigue and acid corrosion process. In addition, these prepared ceramic filters still showed a removal efficiency of above 99.9% for PM2.5. Therefore, the MFCF reported in this work exhibited great potential for industrial hot gas filtration.