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The top of the electric arc furnace is generally built with high alumina bricks, and the alumina content is between 75% and 85%. Compared with silica bricks, high alumina bricks have the characteristics of high refractoriness, good thermal shock resistance and high compressive strength. Due to the rich bauxite resources in my country, high alumina bricks have become the main refractory materials for the top of electric arc furnaces, and their service life is about 2-3 times that of silica brick tops. With the development of large-scale ultra-high-power electric furnaces, the service life of high-alumina bricks is also declining, which leads to the further use of fired or unfired magnesia bricks, magnesia-chrome bricks and other alkaline bricks. It can also be hoisted with refractory prefabs poured by merchants. Compared with ordinary masonry roofs, it has the advantages of convenient construction, good integrity, strong resistance to arc radiation, and resistance to rapid cooling and rapid heating.

Characteristic

a.Refractoriness

The refractoriness of high-alumina bricks is higher than that of clay bricks and semi-silica bricks, reaching 1750~1790℃, which belongs to advanced refractory materials.

b,Refractoriness under load

Because of the high Al2O3 in high alumina products, less impurities and less fusible glass body, the softening temperature under load is higher than that of clay bricks, but because mullite crystals do not form a network structure, the softening temperature under load is still lower than that of silica bricks.

C.Slag resistance

There are more Al2O3 in high alumina bricks, which are close to neutral refractory materials, and can resist the erosion of acid slag and alkaline slag. Because of the SiO2 contained in them, the ability to resist alkaline slag is weaker than that of acid slag.