Important Industrial Clay Deposits of the World

摘要

Important kaolin, bentonite, and palygorskite-sepiolite deposits that are processed forrninternational and regional applications are described. The location, geology, physical andrnchemical properties and primary applications of the above mentioned clay deposits are discussed.rnBall clays are kaolinitic clays and are included with the kaolins. The bentonite deposits includernthose that are comprised mainly of sodium montmorillonite, calcium montmorillonite andrnlithium montmorillonite (hectorite). Palygorskite and sepiolite deposits are relatively rare inrnnumber in contrast to the number of kaolin and bentonite deposits but are important industrialrnclays. The term attapulgite is used interchangeably with palygorskite, but the InternationalrnNomenclature Committee favors palygorskite. The term Fuller’s earth is used in England forrnabsorbent calcium bentonite and sometimes in the United States for both calcium bentonite andrnpalygorskite when they are used as absorbents and bleaching earths.rnWorldwide, approximately 40,000,000 tons of kaolin are mined and processed annually,rn11,000,000 tons of bentonite, and 2,700,000 tons of palygorskite and sepiolite. Thus, it can bernseen that the clays are important industrial minerals.