Study And Using Of Alunina-magnesia Pre-casting Brick

The corundum based alunina-magnesia castable for the lining of steel ladles has been researched for many years. In traditional studying, pre-reactive spinel was introduced as MgO source; calcium aluminate cement or microsilica powder as binder, and the castable was used as a monolithic lining for ladle. But there are too much slag sticking on the ladle and serving life is short. In recent years, the study on pre-production brick of alunina-magnesia castable on ladles has been developed. In this paper, the effect of introduction method and content of MgO, partical size distribution, fibers content, selection of binders and dispersant on the properties, such as the slag corrosion resistance, thermal shock resistance, permanent line change, strength and performance properties of alunina-magnesia pre-production brick, were studied systematically.The slag corrosion resistance was studied by static crucible and the speed of corrosions was calculated on the basis of repeated experiments. The thermal shock resistance was tested by rapid water-cooling after treated at 1100°C for 20min. The introduction method of MgO was discussed using structure analysis.AU kinds of different ways (SEM, EDX and X-ray etc.) were used to explore the microstructure of the samples after slag test, according to the result, the basic mechanisms contributing to the slag corrosion resistance of alunina-magnesia syatem castable were investigated.The experimental results show that alunina-magnesia castable with excellent slag corrosion and penetration resistance can be worked out by introducing single magnesia as MgO source, non-cement adhesive, forming spinel from in situ reaction, by optimizing the matrix to reduce reaction between castable and forming low melting point material in slag. The castable with good thermal shock resistance and other performance properties is on the basis of addition q% coarse grain, 2c% fiber. The experimental results were optimized and pre-production bricks were fabricated and applied in 300t ladle wall, which had more than 200 heats in life and the corrosion speed less than lmm per time. In a word, the whole research is successful.