Preparation And Properties Of Multi-functional Honeycomb Ceramic Materials Form Red Mud

The Bayer process used in commercial alumina manufacturing produces red mud(RM)as a waste.Red mud is highly alkaline(pH = 10-12.5)and adversely impacts the environment.Generally,approximately one to two tons of bauxite residues are generated for each ton of alumina produced and in order to protect the environment,it is important to recycle and utilize the red mud waste.Bauxite residues are used in building materials,metal recovery,soil amendment,catalysts,water-gas treatment,and ceramic materials.In this paper,the use of red mud to prepare a honeycomb ceramic carrier suitable for water and gas treatment is described and the composition is found to have significant effects on the microparticles in the released waste gas.The process and materials described here have many applications such as cars,trucks,buses,factory chimneys,air conditioners,and so on.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 ℃.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.The antibacterial and mechanical properties of heat resistant honeycomb ceramic materials produced from red mud industrial waste and doped with Zn and Ag are determined.Excellent antibacterial effects against Escherichia coli(E.coli)are obtained by the plate counting and vibration methods.When 5%and 6%Zn are added to the honeycombs doped with 0.3%Ag,the antibacterial rates reach 98.9%and 99.5%,respectively.The denitration properties of heat resistant honeycomb ceramic materials produced from red mud industrial waste,which loaded denitration catalyst.The experimental results show that impregnation liquid mass concentration of 40%,pH=10 and impregnated three times by ultrasonic immersion method can be obtained high quality of honeycomb ceramic materials.