Study On The Structure And Properties Of Magnesia Porous Materials Prepared By Foaming Method

China is a big country of energy consumption, how to efficient and saving utilize of energy, and take the road of sustainable development has become China’s energy development strategy. Magnesia porous material was prepared using flotation tailings of magnesite, not only making possible the recycling of industrial waste, but also enhancing the thermal efficiency, reducing exothermic temperature and improving the surrounding environment. Therefore, magnesia porous material was prepared using foaming method with main raw materials including of flotation tailing of magnesite, fused magnesia and additives involving sodium hexametaphosphate, sodium citrate and α-Al2O3 powder. Study on the properties of the slurry which was prepared with foaming sodium dodecyl sulfate(SDS) and foam stabilizing dextrin. Magnesia porous material was produced through the process including slip casting, curing, drying and sintering, and study on the effect of process parameters on the phase composition and microstructure of magnesia porous material.The results show that the preparation of suspension slurry belonged to the pseudoplastic fluid, the viscosity of slurry increased and the Zeta potential value decreased with the increasing blowing agent addition. The fluidity of slurry was improved by adding feducing agent and dispersant, the viscosity decreased and the Zeta potential value increased. In general, the larger the viscosity, the smaller the Zeta potential value, the intergranular electrostatic repulsion decreased and the pore diameter of sintered specimens increased. Adding α-Al2O3 could enhance the content of magnesium aluminum spinel, sodium dodecyl sulfate, dextrin, sodium hexametaphosphate and sodium citrate had no impact on the phase composition of sintered specimens. Adding blowing agent could increase the porosity and decrease the thermal conductivity of sintered specimens. The amount of local sintered bodies became less and smaller, the pores were circular closely porosity, and the poreswere distributed around the periclase phase. Furthermore, the content of the reducing agent, dispersant agent and additive should be within a certain range. The slurry occurred irreversible flocculation phenomenon with the increasing sodium hexametaphosphate and sodium citrate, the bubbles were break due to the external force, the apparent porosity of specimens after sintering decreased, and the thermal insulation properties were influenced by the massive local sintered bodies in fracture. With further increasing α-Al2O3 content, the volume expansion appeared because of the drastic spinel phenomenon within the materials, which resulted in the cracked surface.