High alumina bricks are high-performance refractory materials offering exceptional heat resistance, chemical stability, and mechanical strength. Widely used in steel furnaces, cement kilns, glass melting, and chemical reactors, these bricks extend equipment life, reduce maintenance, and ensure operational efficiency under extreme high-temperature conditions.
(1) High refractoriness
(2) High refractoriness under load
(3) Strong slag resistance
(4) High compressive strength
(5) Good stability
(6) Good wear resistance
(1) Iron and steel manufacturing industry: blast furnace, hot blast furnace, electric furnace, ladle, tundish, heating furnace, refining furnace, heating furnace, annealing furnace, cupola
(2) Nonferrous metal industry: smelting furnace, refining furnace, reverberatory furnace, converter furnace.
(3) Building materials industry: cement kiln, glass kiln, ceramic kiln, lime kiln, kiln car, tunnel kiln
(4) Energy and incineration: coke oven, circulating fluidized bed boiler, carbon roaster, incinerator.
|
Item |
Index |
||||
|
Model |
SK35 |
SK36 |
SK37 |
SK38 |
SK39 |
|
Al2O3/% |
≥48 |
≥55 |
≥65 |
≥75 |
≥80 |
|
Fe2O3/% |
≤2 |
≤2 |
≤2 |
≤2 |
≤2 |
|
Body density（g/cm3） |
2.15 |
2.2 |
2.3 |
2.4 |
2.5 |
|
Refractory |
≥1750 °C |
≥1770 °C |
≥1790 °C |
≥1790 °C |
≥1790 °C |
|
Change in heating permanent line/% |
1450℃×2h -0.4~0.1 |
1450℃×2h -0.4~0.1 |
1450℃×2h -0.4~0.1 |
1500℃×2h -0.4~0.2 |
1500℃×2h -0.4~0.2 |
|
Cold pressing strength |
≥39Mpa |
≥44Mpa |
≥49Mpa |
≥54Mpa |
≥65Mpa |
|
Apparent porosity (≤) |
≤22% |
≤22% |
≤23% |
≤23% |
≤21% |
|
Load softening temperature [0.2MPa*0.6%]≥ |
≥1420 °C |
≥1470 °C |
≥1500 °C |
≥1520 °C |
≥1530 °C |
High alumina brick is one of the most widely used refractory materials in high-temperature industrial furnaces and kilns. Thanks to its high alumina content, excellent thermal stability, strong mechanical strength, and good resistance to chemical corrosion, high alumina brick has become a core lining material in industries such as steelmaking, cement production, glass manufacturing, non-ferrous metallurgy, and power generation.
As furnace operating temperatures continue to rise and energy efficiency requirements become stricter, selecting the right high alumina brick is no longer just a matter of temperature rating. It involves understanding alumina content, physical properties, thermal behavior, service environment, and lifecycle cost. This guide provides a comprehensive overview of high alumina brick, helping engineers, procurement managers, and furnace designers make informed decisions.
High alumina brick is a type of refractory brick made primarily from bauxite or other alumina-rich raw materials. Compared with traditional fire clay bricks, high alumina bricks contain a higher percentage of aluminum oxide (Al₂O₃), typically above 48%. The increased alumina content significantly improves refractoriness, load-bearing capacity at high temperatures, and resistance to slag and chemical attack.
High alumina bricks are classified as shaped refractory products and are manufactured through processes such as crushing, batching, high-pressure forming, and high-temperature firing. Depending on alumina content and microstructure, they can be used in both hot-face linings and structural zones exposed to extreme thermal and mechanical stress.
The defining characteristic of high alumina brick is its alumina content. Common composition ranges include:
48–55% Al₂O₃: Entry-level high alumina brick, often used as an upgrade from fire clay brick
60–65% Al₂O₃: Medium-grade high alumina brick with improved refractoriness and strength
70–75% Al₂O₃: High-performance grade suitable for severe service conditions
Above 80% Al₂O₃: Premium high alumina brick approaching corundum-based refractories
In addition to alumina, high alumina bricks contain controlled amounts of silica (SiO₂), iron oxide (Fe₂O₃), calcium oxide (CaO), and alkali oxides. The balance of these components directly affects thermal expansion, slag resistance, and high-temperature mechanical behavior.
The performance of high alumina brick in industrial furnaces depends on a combination of physical and thermal properties rather than a single parameter.
High alumina bricks exhibit refractoriness typically above 1700°C, with load softening temperatures significantly higher than those of fire clay bricks. This makes them suitable for zones subjected to both high temperature and mechanical load.
High alumina bricks offer high cold crushing strength, allowing them to withstand installation stress and operational load without deformation or cracking.
Although higher alumina content generally improves refractoriness, thermal shock resistance depends on microstructure and porosity design. Properly engineered high alumina bricks maintain good resistance to rapid temperature changes, especially in batch or intermittently operated furnaces.
High alumina bricks show excellent resistance to acidic and neutral slags. In cement kilns and steel furnaces, they perform well against clinker, alkali vapors, and molten metal splash under appropriate conditions.
High alumina bricks can be classified in several ways, depending on application requirements:
By alumina content (48%, 60%, 70%, 80%+)
By bulk density (dense high alumina brick vs lightweight high alumina brick)
By application (furnace lining, kiln lining, backup insulation layer)
Dense high alumina bricks are typically used in hot-face linings where direct exposure to flame, molten material, or slag occurs. Lightweight high alumina bricks, on the other hand, are designed for backup insulation layers to reduce heat loss and improve energy efficiency.
High alumina bricks are used across a wide range of high-temperature industrial equipment due to their versatility and reliability.
In steelmaking and rolling operations, high alumina bricks are commonly used in reheating furnaces, soaking pits, ladle linings, and tundish impact zones. Their ability to withstand high temperatures and mechanical abrasion makes them suitable for demanding steel furnace environments.
Cement kilns expose refractory materials to high temperatures, alkaline atmospheres, and abrasive clinker. High alumina bricks are widely used in kiln transition zones, cooler linings, and preheater areas where both thermal and chemical stability are required.
In glass furnaces, high alumina bricks offer good resistance to molten glass corrosion and thermal cycling, particularly in superstructure and regenerator areas.
High alumina bricks are also applied in aluminum melting furnaces, copper smelters, incinerators, and boiler systems, where stable performance and long service life are critical.
A common question during refractory selection is whether to use high alumina brick or fire clay brick. The answer depends on operating conditions.
Fire clay bricks typically contain 30–45% Al₂O₃ and are suitable for moderate temperature applications. High alumina bricks, with higher alumina content, offer:
Higher maximum service temperature
Better load-bearing performance
Improved resistance to slag and chemical attack
Longer service life in harsh environments
While fire clay bricks may offer lower initial cost, high alumina bricks often provide better long-term value by reducing maintenance frequency and unplanned downtime.
The cost of high alumina brick varies depending on alumina content, raw material quality, manufacturing process, and brick size. Higher alumina grades typically involve higher initial cost, but this should be evaluated against expected service life and performance stability.
In many industrial furnaces, high alumina bricks demonstrate significantly longer lifespan compared with lower-grade refractories. Reduced replacement frequency, improved energy efficiency, and lower risk of emergency shutdowns contribute to a lower total cost of ownership.
Selecting the appropriate high alumina brick requires a clear understanding of furnace operating conditions:
Maximum operating temperature
Thermal cycling frequency
Chemical atmosphere (acidic, alkaline, or neutral)
Mechanical load and abrasion level
Desired service life and maintenance schedule
Consulting with an experienced refractory manufacturer ensures that the alumina grade, density, and brick design match the actual service environment rather than relying solely on nominal temperature ratings.
High alumina brick quality depends heavily on raw material selection, firing temperature control, and quality inspection. Reliable manufacturers implement strict control over chemical composition, bulk density, apparent porosity, and dimensional accuracy to ensure consistent performance in industrial applications.
Q1: What is the maximum temperature high alumina bricks can withstand?
High alumina bricks typically handle continuous service temperatures of 1600°C–1800°C, with peak tolerances slightly higher depending on installation.
Q2: What are the main components of high alumina bricks?
They are made primarily of bauxite, corundum, and calcined alumina aggregates with binders to provide cohesion and mechanical strength.
Q3: Are high alumina bricks suitable for steel furnaces?
Yes, they are widely used in electric arc furnaces, ladles, and tapholes for their heat and chemical resistance.
Q4: How do high alumina bricks compare with fireclay bricks?
High alumina bricks offer superior temperature resistance, wear resistance, and chemical stability, especially in high-temperature industrial settings.
Q5: Can high alumina bricks be used in glass melting furnaces?
Yes, they resist molten glass corrosion and maintain structural stability under high heat.
Q6: How does chemical composition affect brick performance?
Higher alumina content improves heat resistance and chemical stability, while controlled additives enhance thermal shock resistance and mechanical strength.
Q7: What factors influence the lifespan of high alumina bricks?
Temperature, slag composition, mechanical wear, installation quality, and regular maintenance all impact durability.
Q8: Can high alumina bricks be used outdoors?
Yes, but they should be stored dry and protected from moisture before installation.
Q9: What industries benefit most from high alumina bricks?
Steelmaking, cement, glass production, petrochemical processing, and power generation industries.
Q10: How are high alumina bricks installed in rotary kilns?
Bricks are aligned and bonded using refractory mortar, with preheating and controlled curing to prevent cracks and ensure long-term stability.
Q11: Can high alumina bricks be combined with other refractory materials?
Yes, they are often used alongside magnesia or chrome corundum bricks to optimize performance in specific furnace zones.
Q12: How do high alumina bricks resist thermal shock?
Through low porosity, high density, and controlled alumina composition, they maintain integrity under rapid heating and cooling cycles.
Q13: Are high alumina bricks environmentally safe?
Yes, they are non-toxic and safe to handle, though dust control and protective equipment are recommended during installation.
Q14: How do I select the best high alumina brick for my equipment?
Consider operating temperature, chemical exposure, mechanical load, construction method, and cost vs longevity; consult product specifications for precise guidance.
Q15: What maintenance is required for high alumina brick linings?
Regular inspection, joint repair, and gradual preheating prevent premature failure and extend operational life.
High alumina bricks are a versatile and durable solution for industrial furnaces, kilns, and high-temperature equipment. Their excellent heat resistance, chemical stability, and mechanical strength make them indispensable for steel, cement, glass, chemical, and power generation industries.
By understanding composition, properties, applications, and installation best practices, plant managers and engineers can maximize equipment life, reduce maintenance downtime, and improve operational efficiency.
High alumina poly light brick is a high quality lightweight refractory material.
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High alumina fine powder is a powder material with alumina (Al2O3) as the main component.
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