Corundum Series Refractory Bricks

Corundum Brick

Name: Corundum Brick
Brand: XZK

Corundum bricks with 95-99% Al2O3 for glass furnace side walls, burner ports, throats and forehearths. Dense sintered body with no glassy phase, high abrasion resistance and refractoriness above 1790C. Grades XZK-CR95 and XZK-CR99.

Al₂O₃:≥95%

Bulk density:≥3.15g/cm³

Apparent Porosity:≤18%

Cold Crushing Strength:≥80MPa

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Corundum Brick Overview

Corundum bricks are high-performance refractories built on a corundum (α-Al₂O₃) crystal matrix, with alumina content from 95% to 99%. They are formed under high pressure and sintered at 1750–1800°C, producing a dense body that combines very high refractoriness with outstanding mechanical strength and abrasion resistance.

XZK Group manufactures corundum bricks in grades XZK-CR95 and XZK-CR99, both produced in our own plant in Xinmi, Henan. They are specified wherever a glass furnace or metallurgical vessel combines high temperature with mechanical wear or chemical attack.

What Makes Corundum Different from Other Alumina Refractories

Alumina content alone does not define a corundum brick — crystal phase does. High alumina bricks carry 55–80% Al₂O₃ in a mullite-corundum structure. Corundum bricks run from 95% upward, with corundum as the dominant phase. That difference in crystal structure is what drives the performance gap:

Hardness close to diamond. Corundum ranks 9 on the Mohs scale, second only to diamond among industrial minerals. The brick resists the abrasive batch particles and melt flow that erode fireclay linings in months.
Refractoriness above 1790°C with a load softening temperature that keeps the brick dimensionally stable under sustained load.
Chemical inertness in oxidising and weakly reducing atmospheres, including resistance to molten glass, metal slag and alkaline media.
No glassy phase. Because the body is ceramically bonded rather than fused cast, there is no vitreous phase to exude into the melt — an important distinction in glass contact applications where exudation causes stone and cord defects.

Technical Specifications

Technical Properties	XZK-CR95	XZK-CR99
Al₂O₃ (%)	≥ 95	≥ 99
Fe₂O₃ (%)	≤ 0.3	≤ 0.3
Bulk Density (g/cm³)	≥ 3.15	≥ 3.20
Apparent Porosity (%)	≤ 18	≤ 17
Cold Crushing Strength (MPa)	≥ 90	≥ 80

Test methods follow GB/T and ISO practice; ASTM equivalents and full certificates of analysis are issued with every shipment.

Corundum Brick or Chrome Corundum Brick?

Both belong to the corundum family, and both are made by XZK. The choice comes down to the dominant wear mechanism:

Specify straight corundum (XZK-CR95 / CR99) for maximum purity and abrasion resistance — glass contact zones, forehearths and high-purity applications.
Specify chrome corundum where alkali attack, slag wetting or thermal cycling dominate — regenerators, burner blocks and reversal zones. The Cr₂O₃ fraction suppresses slag wetting and raises thermal shock resistance.

For applications that combine alkali attack with severe thermal shock, the patented Three-Resistant (3R) brick adds a zirconia fraction that arrests crack propagation.

Industry Applications

Glass Industry: Side walls and burner ports of melting furnaces.
Metallurgical Industry: Roofs of blast furnaces and linings of electric furnaces.
Chemical Field: Linings of high - temperature reaction kettles and distillation towers.
Ceramics and Environmental Protection: Firing zones of tunnel kilns and linings of waste incinerators.

Where Corundum Bricks Are Used in a Glass Furnace

In a glass tank, corundum bricks appear in the zones where radiant heat meets aggressive chemistry:

Melter side walls and burner ports. Corundum's combination of refractoriness and hardness resists both the radiant load and the flame scour at the port.
Superstructure and tuck stones. Dense corundum grades hold their volume against alkali vapour migration, which is what opens joints in less stable materials.
Forehearth channels and roofs. With no glassy phase to exude, corundum protects glass quality in the conditioning section.
Throat and throat hanging walls. The highest melt velocities in the tank pass through the throat, where abrasion resistance decides campaign life.
Tank bottom support and levelling courses, working with zircon and AZS materials to seal the bottom structure.

Manufacturing and Quality Control

Corundum refractories are sensitive to process variation: uneven porosity between batches becomes uneven wear in service, and uneven wear ends campaigns early. We control density with press force rather than operator judgement, running four automatic batching lines into 20 CNC presses from 630 to 2000 tonnes. Firing takes place in four 108-metre fully automatic tunnel kilns and five ultra-high-temperature shuttle kilns, giving the uniform soak that corundum bodies need to complete densification.

Every batch is tested for bulk density, apparent porosity, cold crushing strength and refractoriness under load, and ships with a certificate of analysis. XZK Group holds ISO 9001, ISO 14001, ISO 45001 and ISO 50001 certification and operates the Henan Provincial Engineering Technology Research Centre for Sintered Refractories for Glass Furnaces.

Related Refractory Products

Corundum bricks are normally supplied as part of a zoned glass furnace lining. They work alongside corundum mullite bricks, chrome corundum bricks, zircon bricks, sintered AZS bricks, mullite bricks and sillimanite bricks. See the full corundum bricks range for zoning guidance, or browse all refractory products.

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About XZK Group

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Innovation

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Facilities

Honors

Product Portfolio

Specializing in premium zircon, corundum, sintered AZS, and monolithics. With a $70M+ annual output, we deliver durable linings for global high-temp industries.

Capacity

✔ 4 automated microcomputer batching systems.

✔ 4 ultra-high-temp tunnel kilns & 5 shuttle kilns.

✔ 20+ CNC hydraulic presses (630-1500T).

✔ Digitalized workshops with 100,000T annual capacity.