Refractory brick classification, what is breathable corundum brick?
Release time:
2023-11-07
For refractory bricks, some conditions of use are to use the high porosity and high air permeability of the product. At present, the steel mill widely used ladle bottom blowing argon breathable corundum brick, with gas blowing metal, that is, with gas blowing liquid with corundum brick. The use of the same particle size, the use of filler and binder in the sintering process to tightly bond the particles together, so that the product becomes a solid block, and the same size of the particle material determines the shape and size of the pores. If it is necessary to increase the breathability of the product, it is also necessary to add a burn-in additive whose particle size should be the same as the filler size, and the shape should be the same as it.
Porous, breathable corundum bricks used for blowing metals have certain advantages in the use of corundum-based magnesia. The breathable corundum brick for industrial application can be made of 80% of No.63 electrofused corundum as granular material, and the mixture of industrial alumina (65%) and refractory clay (35%) as binder, which is 20%. The binder should be finely ground together in a cylinder mill, and the content greater than 60 μm should not exceed 1% ~ 1.5. Mud shall be mixed on a wet mill for 10min with a moisture content of 4.3 ~ 5%, and then sieved on a sieve with a mesh size of 5mm. The brick is formed on a hydraulic press with a pressure of 35MPa, and the density of the brick is 2.60g/cm3. The product is fired in a tunnel kiln or inverted flame kiln at a firing temperature of 1570 ℃, holding for 22±2h, and the total firing time cannot be less than 150h.
There are many manufacturing methods for breathable corundum bricks. 20% binder is prepared by grinding corundum waste (60%) and clay (40%) together. The moisture content of clay is 4% ~ 5%, and the pressed brick blank has a density of 2.60g/cm3:, which is fired in a tunnel kiln for 86h, with a maximum firing temperature of 1560 ℃ and heat preservation (5±1)h.
Other uses fused corundum as aggregate, pure calcium aluminate cement and SiO2 ultrafine powder as binder, phosphate as dispersant, and ultra-low cement castable process.
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