Refractory plays an indispensable role in modern industrial production, and high-alumina brick, as the outstanding one, is widely used in various high-temperature industrial fields with its excellent performance. This paper will introduce the performance characteristics of high alumina brick and its advantages in practical application in detail.

I. Definition and classification of high alumina brick

High alumina brick is a kind of refractory brick made of high alumina clinker as the main raw material through high pressure forming and high temperature sintering. Its alumina (Al₂O₃) content is usually between 30% and 85%. According to the different alumina content, high alumina bricks can be divided into several grades, such as SK-32, SK-34, SK-36, SK-38, etc., and the performance indexes of each grade are different to meet the needs of different industrial scenes.

II. Performance characteristics of high alumina brick

(1) High temperature performance

High refractoriness: The refractoriness of high-alumina brick ranges from 1710°C to 1850°C, and it can withstand extremely high temperatures, making it an ideal material for lining of high-temperature furnaces. For example, in steelmaking furnaces and ironmaking blast furnaces in iron and steel industry, high-alumina bricks can remain stable in extremely high temperature environment, effectively preventing the furnace body from being eroded by high-temperature melt.

Low creep rate at high temperature: Under the condition of high temperature, the creep rate of high-alumina brick is extremely low, which means that it can maintain the stability of shape and structure under the action of high temperature for a long time, and will not be deformed or collapsed due to high temperature, thus prolonging the service life of the furnace.

Good thermal shock resistance: high-alumina brick has excellent thermal shock resistance and can remain intact under the condition of rapid temperature change. For example, in glass kilns and ceramic kilns, the start-stop and temperature adjustment of kilns are frequent, and high-alumina bricks can effectively resist the thermal stress and reduce the damage caused by thermal shock.

(2) Chemical properties

Low iron content and impurities: High-alumina brick has low iron content (Fe₂O₃ content usually does not exceed 2.0%) and few impurities, which makes it have better chemical stability in reducing atmosphere and is not easy to be oxidized or reduced, thus prolonging its service life.

Excellent corrosion resistance: high alumina brick has good corrosion resistance to acidic and alkaline slag. In nonferrous metal smelting furnace, the chemical properties of slag are complex, and high alumina brick can effectively resist the chemical erosion of slag and protect the furnace structure.

(3) Physical properties

High density and low porosity: the bulk density of high-alumina brick is between 2.0 and 2.6 g/cm, and the porosity is low (usually less than 24%), which makes it have good corrosion resistance and wear resistance. In cement kiln and lime kiln, high alumina brick can effectively resist the erosion of dust and high temperature airflow and reduce wear.

High strength: The high cold pressure of high-alumina brick is high (above 550 kg/cm), and it can keep the structural integrity under the dual action of high temperature and mechanical stress. For example, in large ladle and ladle, high alumina brick can withstand the double test of heavy load and high temperature to ensure safe operation.

(4) dimensional accuracy and stability

High-alumina bricks have high dimensional accuracy, can be spliced and installed accurately, and reduce gaps and errors in construction. At the same time, its volume stability at high temperature is good, and it will not expand or contract obviously due to temperature change, thus ensuring the structural integrity and sealing of the furnace.

III. Application fields of high alumina bricks

The excellent performance of high-alumina brick makes it widely used in many industrial fields:

Iron and steel industry: used for lining of blast furnace, hot blast stove, ladle, ladle, heating furnace and other equipment, which can effectively resist the erosion of high-temperature molten metal and slag and prolong the service life of equipment.

Non-ferrous metal industry: In smelting furnaces and refining furnaces of copper, aluminum, lead, zinc and other non-ferrous metals, high-alumina bricks can withstand high temperature and chemical erosion to ensure the smooth production process.

Building materials industry: In cement kilns, glass kilns, ceramic kilns and other equipment, high-alumina bricks can resist the erosion of high temperature and dust, and improve the operation efficiency and service life of equipment.

Energy field: In coke ovens, boilers, garbage incinerators and other equipment, high-alumina bricks can effectively resist high temperature and corrosion and ensure the safe operation of equipment.

Civil field: In civil fireplaces, pizza oven and other equipment, high-alumina bricks can provide good thermal insulation and high-temperature resistance, and meet daily use requirements.

IV. Future development of high alumina bricks

With the continuous progress of industrial technology, the performance requirements of refractories are getting higher and higher. As an important refractory, high alumina brick is constantly undergoing technological innovation and product upgrading. For example, by adding special additives and adopting advanced production technology, the thermal shock resistance, corrosion resistance and high temperature strength of high-alumina bricks are further improved to meet more demanding industrial application requirements.

In a word, high alumina brick occupies an important position in the field of refractories with its excellent high temperature performance, chemical stability and physical properties. Its wide application and continuous technological innovation make it one of the indispensable refractories in modern industry.