Multi-functional honeycomb ceramic materials produced from bauxite residues

Highlights: • Novel application of red mud for environmentally benign processes. • Honeycomb ceramic microstructure and characterization by XRD and SEM. • Honeycomb ceramic carrier to promote the application in various fields. • Honeycomb ceramic carrier will create environmental and economic significances. - Abstract: Red mud is a hazardous waste produced by the Bayer process during commercial production of alumina. In this study, red mud is recycled to produce industrial honeycomb ceramic materials. The materials and processing parameters including the type and size the pore-forming agent, sintering temperature, and stripping methodology are studied. The optimal sintering temperature is determined to be 1075 °C. The bending strength, porosity, water absorption capacity, and bulk density are investigated by X-ray diffraction and scanning electron microscopy. The bending strength exceeds 32.66 MPa after addition of calcium carbonate but the porosity and water absorption capacity diminish to 28.6% and 12.6%, respectively. Incorporation of coal powders increases the porosity and water absorption capability to 36.0%, 20.24%, respectively, but the bending strength drops to 21.69 MPa