PROPERTIES AND MICROSTRUCTURE OF METAL FE REINFORCED UNBURNED MAGNESIA ALUMINA BRICK FOR CEMENT KILN

摘要

The metal phase reinforced unburned MgO-Al_2O_3 brick was prepared using fused magnesia, Fe and (X-Al_2O_3 micro powder as main raw materials and inorganic salt as a binder. The influence of Fe content, the method of adding Fe and treatment temperature on the unburned brick's properties and microstructure were investigated. The results show that when the content of Fe increased, there is no difference in the samples' properties after treated at 110°C for 24 hours, and after treated at 1000°C and 1550°C for 3 hours, the bulk density and cold compressive strength increase, but the properties worsen when adding too much Fe. The Fe adding method also has some effect on the samples' properties, it is useful to improve the properties when adding some ferreous additive. The microstructures and phases of unburned magnesia-hercynite brick was analyzed by SEM and XRD, it was observed that after treated at 1000°C, hercynite formed in situ, when the temperature increased to 1550°C, hercynite grew better.The typical physical properties of the unburned magnesia-hercynite brick is that the bulk density is 3.05g/cm~3, the apparent porosity is 15%, the cold compressive strength is 69MPa, the hot modulus of rupture at 1400°C for 0.5 hour is 4.6 MPa, adhesive strength and thermal shock resistance are similar to the direct-boned magnesia-chromite brick's.