white corundum, brown corundum and black corundum

2. Alumina content
- White corundum: Alumina content ≥99.2%, the highest among the three types of corundum.
- Brown corundum: 94%≤alumina content≤75%.
- Black corundum: 45%≤alumina content≤75%, the alumina content is relatively low.
3. Hardness
- White corundum hardness: ≥ brown corundum hardness ≥ black corundum hardness, white corundum has the highest hardness, black corundum has a relatively low hardness.

4. Application
White corundum:
- It belongs to high-end applications, mainly used for solid structures and coated abrasives, wet or dry sandblasting.
- Suitable for ultra-fine grinding and polishing in the crystal and electronics industries, such as polishing precision instruments, etc. Because it is white, polishing will not affect the color of the workpiece, so it is often used for polishing high-end jewelry.
- It can also be used to make high-grade refractory materials, etc.
Brown corundum:
- It is widely used in the market and is a commonly used abrasive, which can be used for most objects.
- Due to its high temperature resistance, abrasion resistance, high strength, high hardness, and good wear resistance, it is widely used in blast furnace linings, spark plugs, coated molds, furnace walls and roofs of high-temperature furnaces, polishing and grinding, refractory materials, anti-skid and wear-resistant floor materials, etc.
- It can be used for the production and processing of refractory materials, polishing and grinding of fine instruments, and auxiliary raw materials for wear-resistant materials.
Black corundum:
- It is mainly used for special purposes, such as rough processing of object surfaces, such as rust removal of ship hulls, stone tablet carving, etc.
- It can also be used as an anti-skid and wear-resistant material, and is used in parking lots, airports and other roads to play an anti-skid role.
- It can be used for polishing aluminum products and stainless steel, making sandpaper, emery cloth and resin abrasives, etc.

5. Other characteristics
- White corundum: high hardness, strong wear resistance, good thermal stability, high toughness, high grinding efficiency, strong precision processing ability, environmental protection and energy saving, acid and alkali corrosion resistance, excellent self-sharpening, uniform particles, high purity and cost-effectiveness. These characteristics make white corundum an ideal abrasive material and widely used in grinding and polishing in various fields.
- Brown corundum: moderate hardness, high toughness, good self-sharpening, low sand consumption, recyclable, good finish of grinding parts, and stable chemical composition, wear resistance, acid and alkali resistance, abrasive has a shell-like fracture with sharp edges and corners, and can form new edges and corners during continuous grinding and grading, and the grinding ability is not weak.
- Black corundum: It has good self-sharpening, less heat generation during grinding, good finish of processed parts, and good hydrophilicity. Its power consumption during smelting is lower than that of brown corundum, about two-thirds of that of brown corundum.