Kaoling

Kaoling, also known as kaolin or china clay, is a hydrous aluminum silicate mineral primarily composed of the clay mineral kaolinite (Al2Si2O5(OH)4). It forms soft, white to off-white clays that are highly plastic when wet and tend to become very white and inert on firing. Kaolin is valued for its whiteness, fine particle size, and chemical stability, which make it useful across a range of industries.

The name kaolin derives from the Chinese gaoling (高岭), the name of a hill in the Jingdezhen region long associated with porcelain clay. European traders adopted the term in the 18th century, and it has since become the standard English name for the material.

Geologically, kaolin forms by the weathering of feldspar-rich rocks or by hydrothermal alteration of aluminous minerals, producing fine, plate-like crystals that accumulate as soft clays. Deposits vary in purity and brightness and are split into grades for ceramics, paper, fillers, and other uses.

Processing generally involves mining, washing and beneficiation to remove impurities, drying, and sometimes calcination to adjust brightness or firing properties. In ceramics, kaolin is a key component of porcelain bodies and can act as a glaze additive; in industry, it is used as a filler or coating in paper, plastics, rubber, cosmetics, and pharmaceuticals.

Global production is concentrated in a few countries, with major producers including China, the United States, the United Kingdom, Brazil, and Greece. Environmental and social considerations accompany mining and processing, including land rehabilitation and water management.