Important industrial clay deposits of the world

摘要

Important kaolin, bentonite, and palygorskite-sepiolite deposits that are processed for international and regional applications are described. The location, geology, physical and chemical properties and primary applications of the above mentioned clay deposits are discussed. Ball clays are kaolinitic clays and are included with the kaolins. The bentonite deposits include those that are comprised mainly of sodium montmorillonite, calcium montmorillonite, magnesium montmorillonite (Saponite) and lithium montmorillonite (hectorite).Palygorskite and sepiolite deposits are relatively rare in contrast to kaolin and bentonite deposits but are important industrial clays. The term attapulgite is used interchangeably with palygorskite, but the International Nomenclature Committee favors palygorskite. The term Fuller’s earth is so used in England for the absorbent calcium bentonite and sometimes in the United States for both calcium bentonite and palygorskite when they are used as absorbents and bleaching earths. Wordwide, approximately 40,000,000 tons of kaolin are mined and processed annually, 11,000,000 tons of bentonite, and 2,700,000 tons of palygorskite and sepiolite. Thus, it can be seen that the clays are important industrial minerals.