Industrial Usage of Corundum

Corundum is a crystalline form of aluminum oxide (Al₂O₃) with traces of iron, titanium and chromium. It is a rock-forming mineral. It is one of the naturally transparent materials, but can have different colors when impurities are present. Transparent specimens are used as gems, called ruby if red and padparadscha if pink-orange. All other colors are called sapphire, e.g., "green sapphire" for a green specimen.

Because of corundum's hardness (pure corundum is defined to have 9.0 Mohs), it can scratch almost every other mineral. It is commonly used as an abrasive on everything from sandpaper to large machines used in machining metals, plastics, and wood. Some emery is a mix of corundum and other substances, and the mix is less abrasive, with an average Mohs hardness of 8.0.

Usage

Corundum is moderate in hardness and it doesn't contain free silica, so it is an ideal material for environmental sandblasting. Corundum is also used in sandblasting of stainless steel to remove rust. 

Corundum is used as raw material for sandpaper and abrasive cloth thanks to its sharpness and high hardness.

Garnet abrasive micro powder have been widely used in precision instrument teletron, optical glass, single crystalline silicon, crystal glass, jade ware as a kind of advanced grinding material. Besides that, corundum can also be used in conservation and restoration of architectural heritages.

Corundum can be used as stuffing bulking agent for resin bonded abrasives products and can achieve satisfactory effect.