Effects Of Binders On Properties Of Alumina Magnesia Based Castable

In this artical, corundum, fused magnesia,α-alumina powder and Magnesia-Alumina spinel were used as raw material. And pure calcium alumina cement, silica powder,ρ-alumina powder and Alumina-gel powder were used as different bonder agents. On the basis, the physical properties of castable using different conjugation agent were compared, and the relationships between bonder agent and slag resistance of alumina-magnesia castable, the slags refer converter vanadium-titanium slag and converter slag.The results show that alumina-magnesia castable bonded by Alumina-gel powder have excellent volume stability, higher cold compressive strength and suitable strength ratio in high, medium and low temperature. And either the vanadium-titanium slag from PANZHIHUA IRON & STEEL (GROUP) CO. or the slag from WUHAN IRON & STEEL (GROUP) CO., the slag resistance of alumina-magnesia castable that combined with gel orρ-alumina powder is better, the second is bonded with silica powder, the worst is the castable combined with cement. The analysis of sample microstructure exhibit that high and low melting point phase were formed which staggered distribution of each other in the slag corrosion layer of the castable bonded by Alumina-gel powder orρ-alumina powder, such as MA, CA2, CA6 and C2AS etc. In contrast, the number of high melting point phase is more in the castable samples combined with Alumina-gel powder orρ-alumina powder eroded by the slag from WUHAN IRON & STEEL (GROUP) CO., and has a relatively dense combination.Alumina-magnesia castable has excellent slag resistance and good thermal shock resistance, and mgnesia-alumina spinel plays a very important role as one of the components. Magnesia binder was the median particle size under 10μm and mainly composed of MgO and SiO₂. In the paper, magnesia binder was used instead of above mentioned to get more excellent slag resistance and thermal shock resistance for mgnesia-alumina spinel got in situ reaction by MgO and Al₂O₃ in high temperature. At the same time, for the bimodal particle size distribution of the magnesia binder, the rapid expansion of castable lead to structural damage caused by generate excessive speed was prevented. The results show that the magnesia combined castable have the same combined effect as bonded by Alumina-gel powder orρ-alumina powder, not only has great strength, but also has good slag resistance, and special the high thermal shock resistance. But the addition of magnesia binder is too much or too little, the performance of aluminum-magnesium casting material will be reduced.Compared the physical properties and the slag resistance to slag from PANZHIHUA IRON & STEEL (GROUP) CO. of the Alumina-magnesia castable combined by magnesia, and in the castable, white corundum, tabular alumina, or corundum were used for the aggregate respectively. The results show that the three different castable all have high strength, and good slag resistance. The line rate of change after high temperature of the castable made by white corundum or tabular aluminafiring has micro swell, while the castable made by corundum has greater contraction. Thermal shock resistance of alumina-magnesia castable made by white corundum is the best.The performances of castable combined by magnesite-alumina spinel powder or magnesia and Alumina-gel powder composite binder did not have advantages compared the other binders. Although the breaking strength and compressive strength at room temperature of the alumina-magnesia castable combined by magnesia is lower than the castable combined by Alumina-gel powder, the strength after sintering in medium and high temperature is greater, slag resistance and thermal shock resistance was better than that.