Arc-shaped refractory bricks are indispensable key materials in high-temperature industrial applications. Specifically designed for the construction of circular or arc-shaped furnace structures, they play a vital role in metallurgy, chemical engineering, and energy industries due to their unique shape and superior performance.
I. Basic Concepts and Characteristics of Arc-shaped Refractory Bricks
Arc-shaped refractory bricks are irregularly shaped refractory products. One end is a convex semi-circle, while the other end is a groove, forming an overall semi-circular design. This special structure allows them to perfectly adapt to circular furnaces or curved industrial equipment. Compared to ordinary straight refractory bricks, curved refractory bricks have the following significant advantages:
Flexible Roundness Adjustment: Due to the rounded design at both ends, the roundness can be adjusted by moving the bricks back and forth during construction, ensuring a perfect circle even with slight dimensional deviations.
Precise Joint Control: After construction, the joints are generally about 1 mm, with vertical joints reduced by 70% compared to standard bricks, effectively preventing molten iron from moving up and down and penetrating the joints, causing erosion.
Strong Structural Stability: They fit tightly against the furnace wall, reducing heat loss, improving energy efficiency, and enhancing the overall structural sealing and stability.
High Construction Efficiency: Compared to traditional straight bricks, curved bricks are easier to install, reducing construction time and labor costs.
II. Material Classification and Performance Characteristics
Arc-shaped refractory bricks are mainly divided into two categories: clay-based and high-alumina-based. With increasing industrial demand, high-alumina arc-shaped bricks are gradually replacing clay-based products as the mainstream in the market due to their performance advantages:
Clay Arc-shaped Bricks
Al₂O₃ content: 30%–46%
Refractoriness: 1580–1770℃
Suitable for medium and low temperature industrial furnaces
Relatively low price, economical and practical
High-alumina Arc-shaped Bricks
Al₂O₃ content: 65%–75% (Grade 26) or 70%–75% (Grade 28)
Refractoriness: Withstanding temperatures above 1500℃
Compressive strength 25MPa, and high-temperature compressive strength ≥18MPa at 1350℃
A low thermal conductivity (0.8～1.0W/(m·K) at 1300℃)
A service life of 4-5 years, extending its lifespan by 25%-67% compared to ordinary bricks
High-alumina arc-shaped bricks exhibit superior performance in thermal shock resistance, corrosion resistance, and high-temperature mechanical strength, making them particularly suitable for high-temperature and highly corrosive environments, such as critical components like steel ladles, molten iron ladles, blast furnaces, electric furnaces, and hot blast stoves.
III. Application Areas and Value
Arc-shaped refractory bricks, with their unique properties, play a crucial role in multiple industrial sectors:
Metallurgical Industry: As a core material for lining steel ladles and molten iron ladles, they improve ladle utilization, reduce masonry labor, and extend equipment lifespan.
Steel Production: Used as linings for blast furnaces, converters, electric furnaces, and other equipment, withstanding the impact of high-temperature molten iron to ensure stable smelting processes.
Energy Sector: Applied as insulation layers for thermal boilers and high-temperature steam pipelines, their thermal conductivity is more than 40% lower than rock wool, controlling pipeline heat loss to within 4%.
Building Materials Industry: Used in cement kilns, glass kilns, and other equipment to ensure stable operation under high-temperature environments.
Environmental Protection Sector: As a lining material for waste incinerators, they withstand high temperatures and chemical corrosion, ensuring safety during incineration.
In practical applications, arc-shaped refractory bricks not only increase equipment capacity (such as increasing the capacity of steel ladles) but also reduce energy consumption (fuel consumption reduced by 22%). A ceramic kiln with a daily output of 8 tons can save over 30,000 cubic meters of natural gas annually.
IV. Specifications and Customization Services
Curved refractory bricks are available in various specifications, and customization services can be provided according to customer needs:
Standard Sizes: Standard straight bricks (230×114×65mm, 230×114×75mm), curved bricks (radius 150-1200mm), wedge-shaped bricks (for kiln arch construction)
Thickness Specifications: Nine common thicknesses are available (C19-C27), used for constructing circular structures of different radii.
Customization Services: For special scenarios such as irregularly shaped reactors and small experimental furnaces, irregularly shaped bricks can be customized through CAD modeling to ensure perfect fit to the inner wall of the equipment.
Performance Customization: Parameters such as Al₂O₃ content (60%-75%) and bulk density (1.0-1.5g/cm³) can be adjusted according to the operating temperature.
V. Construction and Maintenance Points
To ensure the optimal performance of arc-shaped refractory bricks, the following points should be noted during construction and maintenance:
Substrate Preparation: Before construction, clean the surface of the equipment lining of dust, oil, and residue, ensuring a flatness error within 5mm.
Construction Process: Use mullite-based refractory mortar (Al₂O₃ content ≥60%) for construction. The mortar thickness should be controlled at 2-3mm to ensure uniform brick joints.
Staggered Joint Arrangement: The vertical joints of adjacent bricks should be staggered by 1/2 brick length to improve overall structural stability.
Arch Construction: The kiln arch should be constructed symmetrically using wedge-shaped bricks, with a 5-10mm expansion joint reserved in the center.
Cure and Baking: After construction, allow for natural curing for 24-48 hours, followed by staged heating and baking (within 50℃/h).
Regular Inspection: During use, regularly inspect the bricks for cracks, peeling, or other problems, and address them promptly.
In the context of Industry 4.0, curved refractory bricks, as “guardians” of high-temperature industries, will continue to provide a solid guarantee for the efficient, safe, and environmentally friendly operation of industrial production through technological innovation and material upgrades. With continuous technological progress, curved refractory bricks will demonstrate their unique value in more emerging fields, driving the development of high-temperature industries to a higher level.