Four Common Lightweight Bricks for Electric Furnace Linings
The electric furnace body is divided into refractory layer, high temperature insulation layer, medium temperature insulation layer, etc. In order to reduce the heat loss from the furnace wall, shorten the heating time and save heat energy, a layer of lightweight material with strong thermal resistance, fire resistance and heat preservation is often placed near the high-temperature refractory layer of the electric furnace lining. Although the bulk density of this material is only 0.4~1.3g/cm3, it can withstand high temperatures above 1200°C and is widely used as electric furnace lining and high-temperature insulation layer materials.
Currently commonly used lightweight bricks include lightweight clay bricks, lightweight silica bricks, lightweight high alumina bricks, etc.
Lightweight fire clay bricks
Lightweight fire clay bricks are fired with clay clinker as the main raw material, and their bulk density is not greater than 1.3g/cm3.
Lightweight clay bricks are mainly used for lining heat treatment furnaces and can also be used as high-temperature insulation materials for furnaces. Its weaknesses include large porosity, poor wear resistance, low softening temperature under load, and poor thermal stability.
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Lightweight silica brick
Lightweight silica bricks are used in masonry parts where the temperature does not exceed 1550°C. Lightweight silica bricks have a high refractoriness under load (around 1600°C), and the residual expansion at high temperatures is less than 0.2%. They are widely used in furnace tops and furnace walls.
Lightweight high alumina brick
Lightweight high-alumina bricks with high density can be used in parts that are in direct contact with flames, but they are not suitable for contact with high airflow erosion or high-temperature melting parts. Lightweight high-alumina bricks with low density are used for thermal insulation, and the operating temperature should not be higher than 1450°C. Lightweight high-alumina bricks are used to build various high-temperature furnaces and electric furnaces.
Lightweight alumina bricks (foam alumina bricks)
Lightweight alumina bricks are processed and fired from fine powder. Their properties are better than high-alumina bricks. They are often used as insulation materials in high-temperature parts of electric furnaces. The use temperature is 1300°C. If the temperature is too high, shrinkage and deformation will occur.