Description

High-alumina refractory bricks are a type of refractory material. They use high-alumina bauxite clinker as the main raw material, soft clay and waste pulp paper liquid as the binding agent. The mud is made of multi-level particle proportions, which are formed by high pressure and dried. , fired at high temperature. The main component of this refractory brick is Al2O3. If the Al2O3 content is higher than 90%, it is called corundum brick. Due to different resources, national standards are not completely consistent. For example, European countries stipulate that the lower limit of Al2O3 content for high-aluminum refractory materials is 42%. In China, high alumina bricks are usually divided into three grades according to the Al2O3 content: Grade I - Al2O3 content >75%; Grade II - Al2O3 content is 60-75%; Grade III - Al2O3 content is 48-60%. The production process of high alumina bricks and multi-clinker clay bricks is similar. The difference is that the proportion of clinker in the ingredients is higher, which can be as high as 90-95%. The clinker needs to be sorted and screened to remove iron before crushing. The firing temperature Higher, for example, when high alumina refractory bricks such as I and II are fired in a tunnel kiln, the temperature is generally 1500 to 1600°C.

Characteristics of high alumina refractory bricks:

(1) Fire resistance. The refractory resistance of high alumina bricks is higher than that of clay bricks and semi-silica bricks, reaching 1750-1790 degrees, and it is an advanced refractory material.

(2) Load softening temperature. Because high-aluminum products have high Al₂O₃, low impurities, and less fusible glass, the load-softening temperature is higher than that of clay bricks. The load-softening temperature of high-aluminum products is generally above 1420-1550 degrees. However, because the mullite crystal does not form a network structure, the load softening temperature is still not as high as that of silica brick.

(3) Slag resistance. High alumina refractory bricks contain more Al₂O₃, which is close to neutral refractory materials and can resist the erosion of acidic slag and alkaline slag. Because it contains SiO₂, its ability to resist alkaline slag is weaker than that of acidic slag.

(4) Chemical resistance. High-aluminum refractory products are very resistant to corrosion and oxidation and reduction reactions of acidic or alkaline slag and molten metal, and are enhanced as the Al₂O₃ content increases and the harmful impurity content decreases.

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  Application:

Mainly used for lining blast furnaces, hot blast furnaces, electric furnace roofs, blast furnaces, reverberatory furnaces, and rotary kilns. In addition, high alumina bricks are also widely used as open-hearth regenerative checker bricks, plugs for pouring systems, nozzle bricks, etc.