1. The raw materials for smelting brown fused alumina are mainly: bauxite and coke (anthracite).

The raw materials for smelting white corundum: industrial alumina powder.

2. Brown corundum is mainly used for grinding wheel, sand blasting, free grinding, resin grinding tools, coated abrasives, functional fillers, filter media, refractory materials.

White corundum is mainly used in ceramic manufacturing, resin-bonded abrasives, sandblasting, polishing, grinding, precision casting and advanced refractory materials.

3. The density of brown corundum and white corundum in the current national standards are: F/P12 to F/P220 is not less than 3.90g/cm3, and F/P220 is not less than 3.85g/cm3. In actual use, the index used to judge the quality of corundum is generally the alumina content and particle size and hardness of corundum. The density of corundum is rarely mentioned. The density of general abrasives has two densities: bulk density and true density. The bulk density is measured after the corundum particles fill a container, and the true density is measured under vacuum. Below we use the bulk density and true density of the white corundum basic particle size of 44% to 55%:

Bulk density of white corundum: 1.53~1.99g/cm3, white corundum mass/container volume (including voids)

True density of white corundum: 3.95~4.0g/cm3, white corundum mass/container volume (excluding pore volume)