Brown fused alumina, also known as brown aluminum oxide or emery, is a synthetic abrasive produced by fusing bauxite, carbon materials, and iron filings in an electric arc furnace. The resulting material has a characteristic brown color and excellent grinding properties.
Its main chemical component is aluminum oxide (Al₂O₃), typically accounting for 95.00%–97.00% of its composition, with small amounts of iron, silicon, titanium, and other elements. As one of the most widely used conventional abrasives, brown aluminum oxide is valued for its good grinding performance, broad range of applications, and cost-effectiveness.
Characteristics of Brown Fused Alumina
Made from high-quality abrasive-grade bauxite and selected auxiliary materials, brown corundum is refined in an electric arc furnace at temperatures above 2,250°C. After secondary refining, high-intensity magnetic separation removes impurities. Its refractoriness exceeds 1,850°C.
Our brown aluminum oxide features high purity, well-developed crystals, good flowability, a low coefficient of linear thermal expansion, and excellent corrosion resistance.
During use, it maintains good structural stability and resists bursting, excessive breakdown, and cracking. These properties make it suitable for a wide range of applications in the abrasive and refractory industries.
Applications of Brown Fused Alumina
1. Abrasives and Grinding Tools
Brown aluminum oxide is widely used to manufacture grinding wheels, abrasive belts, sandpaper, abrasive cloth, cutting discs, coated abrasives, and bonded abrasives. It is also used in sandblasting, surface grinding, wear-resistant flooring, and waterjet cutting.
2. Refractory Materials
In the refractory industry, brown corundum is used in castables, refractory bricks, ramming mixes, sliding gate plates, nozzles, ladle linings, and furnace lining materials. It is also suitable for investment casting and other high-temperature industrial applications.
Types of Brown Fused Alumina
1. Brown Fused Alumina Lumps
Brown corundum lumps offer high-temperature resistance, corrosion resistance, and high mechanical strength. They are used in refractory applications such as sliding gate nozzles for steel casting, as well as linings for blast furnaces and equipment used in the smelting of rare metals and specialty alloys. Other applications include technical ceramics, spark plugs, heat-resistant coatings, and oxidation-resistant components.
Thanks to their hardness and wear resistance, these lumps are also used to manufacture reactor components, piping, chemical pump parts, mechanical components, wire-drawing dies, pencil-lead extrusion dies, cutting tools, and mold-making abrasives. Further applications include ballistic protection materials, artificial joint components, and sealing rings.
2. Brown Fused Alumina for Roller Sanding Applications
For roller sanding applications, both grain shape and particle size are important factors in material selection. The quality of brown aluminum oxide largely depends on the characteristics of its original raw materials and the subsequent processing methods.
Depending on the intended application, suitable grains may feature uniform particle sizes, rounded or near-spherical shapes, good impact resistance, and clean surfaces. These characteristics help ensure consistent abrasive performance.
3. Brown Fused Alumina Investment Casting Sand
Investment casting sand is produced from brown corundum using specialized processing techniques developed by experienced technical personnel. The controlled manufacturing process helps deliver the grain characteristics required for precision casting.
This material is suitable for applications where refractory performance, dimensional stability, and resistance to high temperatures are essential.
4. Brown Fused Alumina Barmac Sand
Brown aluminum oxide Barmac sand is processed using a Barmac-type production line to achieve the required grain characteristics.
When used in grinding tools, it offers sharp cutting action, low heat generation, a high grinding ratio, and reduced adhesion during use.
Sintered abrasive tools made with this material can develop a deep blue color after firing and exhibit good structural integrity, with fewer mesh-like cracks and rust stains. Washing the material also helps minimize residual dust.
5. Brown Fused Alumina P-Grade Abrasive
Brown corundum P-grade abrasive is calcined at temperatures ranging from 1,000°C to 1,300°C. The resulting angular grains offer strong cutting ability and good self-sharpening performance. Heat treatment further improves their toughness, making them suitable for high-performance coated abrasives.
Typical applications include premium sandpaper and abrasive belts, where consistent cutting performance and durability are important.
6. Brown Fused Alumina Segment Abrasive
Brown aluminum oxide segment abrasive is manufactured from high-quality bauxite, anthracite, and iron filings using modern, specialized production techniques.
It is valued for its short grinding time, high processing efficiency, reliable performance, and competitive cost. These characteristics make it a practical option for industrial grinding and other abrasive applications where productivity and cost control are key considerations.
