Development Of Alumina-magnesia Ladle Precast Bricks Bonded By Aluminum-gel

Alumina-magnesia spinel castable refractory has been used in ladle lining for a long time. Many studies have been explored at home and abroad, such as using premium bauxite and corundum as aggregate, adding MgO to castable refractory in the form of magnesia or spinel and using silica micropowders or cement as binder. In recent years,ρ-Al2O3 and gel powder have also been used as binders, but certain problems exist in the process of production and practical use.Alumina-magnesia spinel precast bricks are extensively used in ladle linings in order to meet the requirements of fast pace of production. Alumina-magnesia spinel precast bricks have excellent slag corrosion and penetration resistance, good workability and quick drying performance. In order to reduce the content of low melting components in ladle precast bricks and to improve high temperature performance of precast bricks, new type of non-cement alumina-magnesia spinel ladle precast bricks bonded by aluminum-gel were studied in this paper. The main contents include the following parts:1. The properties of alumina-magnesia spinel precast bricks with different binders were comparatively investigated;2. The performance of precast bricks with different micropowders such asα-Al2O3 and different amount of additions;3. The properties of precast bricks with different adding form and amount of MgO;4. Influence of different dispersants and additions on the performance of precast bricks;5. Influence of different kinds of explosion-proof agents on the properties of precast bricks;6. Damage mechanism of different parts of the ladle lining and rational selection of brick-type and material. The experimental results show that the precast bricks bonded by 5% aluminum-gel can get suitable room temperature property and have more excellent slag corrosion and penetration resistance and thermal shock resistance than the precast bricks bonded by other binders. By adding 5%α-Al2O3 and corundum micropowders,7% fused magnesia particles and fine powders,0.1% organic fibers and aluminum powders, the precast bricks can attain excellent room temperature and high temperature properties and suitable linear change rate after heat-treatment. Using sodium hexametaphosphate, FDN and ADS as compound dispersants, the precast bricks bonded by aluminum-gel have good rheological behavior and high ratio of performance to price.The field trial results of 300 tons ladle in Ma Steel show that no cold-steel is in slots of precast bricks and stress is relatively modest. There is no structural spalling phenomenon. The effect of trialed precast bricks is good.