At present, refractory prefabricated blocks have basically been used in the electric furnace cover triangle area in China. The main materials are corundum, chromium corundum, high aluminum, and mullite. Due to the good integrity and erosion resistance of the refractory prefabricated blocks, the masonry construction is simple and the construction quality is relatively guaranteed, so that the overall quality of the electric furnace cover has been greatly improved. Corundum (chrome corundum) quality prefabricated parts are generally used in the triangle area of the ultra-high power furnace cover.
The products we produce mainly use fused white corundum or dense corundum, the critical particle size is 5mm, and alumina cement (Al2O3> 80%) is used as the binder. In order to improve the sintering performance of corundum products, a certain amount of ultrafine powder and additives are added. For chrome corundum products, some high-quality chromium oxide powder (Cr203> 95%) or chromium corundum powder (Cr2O3 content is about 13%) is added to increase the viscosity of the slag during high-temperature use, reduce the penetration layer of the slag, and improve the resistance of the product Slag. This kind of corundum and chromium corundum prefabricated blocks are used in the triangle area of the ultra-high power electric furnace cover, and the life span is about 150 furnaces.
The main raw material of corundum castables is corundum (Al203> 98.9%), and fused pure calcium aluminate cement is used as the binder (Al2O3> 80%, Fe2O37%, SiO20.5%). In order to improve the medium temperature strength of the castable and improve its fluidity, part of -Al2O3, ultrafine powder (less than 1 micron accounts for more than 60%) is added, and its specific surface area is 6.8m2 / g. In order to increase the dispersibility of cement and reduce the amount of water added to the castable, an organic water-reducing agent is added with an additional water amount of 5.5%. The sample calcined at 1500 for 5h was observed under a microscope. The product structure is dense and the particles are evenly distributed. The fine particles in the matrix phase are surrounded by fine powder. It has good alkali vapor corrosion resistance, anti-stripping and sufficient medium temperature strength The casting material is used in the triangle area of the ultra-high power electric furnace. The service life is up to 120 furnaces, the shortest is 90 furnaces, and the average service life is 103 furnaces. It meets the technical requirements of steel mills and replaces imported products.