In the classification of refractory bricks, what is a permeable corundum brick?

For refractory bricks, some conditions of use are to utilize the high porosity and high permeability of the product. At present, the ladle bottom argon blowing permeable corundum bricks widely used in steel plants use gas to blow metal, that is, corundum bricks used to blow liquid. The same particle size is used, and the filler and binder are used to tightly bond the particles during the sintering process to make the product a solid block, and the same size of particles determines the shape and size of the pores. If the permeability of the product must be increased, the ember additive should be added. The particle size should be the same as the filler size, and the shape should be the same as it.

The porous permeable corundum bricks used for blowing metal have certain advantages with corundum and magnesium. For industrial applications, breathable corundum bricks can be made of 80% 63# fused corundum as granular material, and a mixture of industrial alumina (65%) and refractory clay (35%) as a binder, which is 20%. The binder should be finely ground together in a drum mill, and the content of particles larger than 60μm should not exceed 1%~1.5%. The mud is mixed on a wet mill, and the mixing is required to be 10 minutes. The mud moisture is 4.3%~5%, and then sieved on a sieve with a mesh size of 5mm. The bricks are formed on a hydraulic press with a pressure of 35MPa, and the density of the bricks reaches 2.60g/cm3. The products are fired in a tunnel kiln or a downdraft kiln, with a firing temperature of 1570℃, and a heat preservation of 22±2h. The total firing time cannot be less than 150h.

There are many methods for manufacturing breathable corundum bricks. The 20% binder is made by grinding corundum waste (60%) and clay (40%) together. The moisture content of the clay is 4%~5%. The density of the pressed brick is 2.60 g/cm3:. It is fired in a tunnel kiln for 86 hours, with a maximum firing temperature of 1560℃ and insulation for (5±1) hours.

Others use fused corundum as aggregate, pure calcium aluminate cement and SiO2 ultrafine powder as binders, phosphate as dispersant, and ultra-low cement castable process.