Kaolin

Kaolin (China clay) HSN: 2508

A white-burning aluminum silicate which, due to its great purity, has a high fusion point and is the most refractory of all clays. Composition: Mainly kaolinite (50% alumina, 55% silica, plus impurities and water). Properties: White to yellowish or grayish fine powder; d 1.8-2.6; darkens and develops clay odor when moistened; insoluble in water, dilute acids, and alkali.

Hydroxides; have high lubricity (slipperiness). Noncombustible.

Occurrence: Southeastern US, England, France. Grade: Technical, NF, also graded on the basis of color and particle size.

Use Filler and coatings for paper and rubber, refractories, ceramics, cement, fertilizers, chemicals (especially aluminum sulfate), catalyst carriers, anticaking preparations, cosmetics, insecticides, paint, source of alumina, adsorbents for clarification of liquids, and electrical insulators.

See Toth process, kaolinite, aluminum silicate, clay.