For magnesia bricks, some conditions of use are the use of high porosity and high gas permeability of the article. At present, steel mills widely use argon-ventilated corundum bricks at the bottom of the ladle, and use gas to blow metal, and aluminum-magnesium carbon bricks are used to blow corundum bricks for liquids. With the same particle size, the filler and the binder are used to tightly bond the particles during the sintering process, so that the product becomes a solid block, and the same size of the pellets determines the shape and size of the pores. If it is necessary to increase the air permeability of the product, it is necessary to supplement the addition of the burnt-in additive to have the same particle size as the filler, and the shape is the same as the shape.

Porous permeable magnesia bricks used to blow metal have certain advantages with corundum-like magnesium. For industrial applications, the ventilated corundum brick can be made of 63% fused corundum 80% granules, industrial alumina (65%) and refractory clay (35%) as a binder, 20%, the binder should be in the barrel mill In the fine grinding together, the content of more than 60μm should not exceed 1% to 1.5%. The mud is mixed on the wet mill, requiring 10 minutes of mixing, the moisture content of the mud is 4.3% to 5%, and then sieved on a sieve having a mesh size of 5 mm. The brick is formed on a hydraulic machine with a pressure of 35 MPa, and the density of the brick is 2.60 g/cm3. The product is fired in a tunnel kiln or a downdraft kiln. The firing temperature is 1570 ° C, the temperature is kept for 22 ± 2 h, and the total firing time is not less than 150 h.

There are many ways to manufacture ventilated corundum bricks. The 20% binder is prepared by co-grinding corundum waste (60%) and clay (40%). The moisture content of the mud is 4%~5%, and the density of the pressed bricks is It is 2.60 g/cm3: it is fired in a tunnel kiln for 86 hours, and the firing temperature is 1560 ° C, and the temperature is kept (5 ± 1) h.

There are also magnesium bricks for the aggregate, pure calcium aluminate cement and SiO2 ultrafine powder as the binder, phosphate as the dispersant, and the ultra-low cement castable process.