bentonitic /ben'tn it"ik/, adj.
/ben"tn uyt'/, n. Mineral.
a clay formed by the decomposition of volcanic ash, having the ability to absorb large quantities of water and to expand to several times its normal volume.
[1895-1900; named after Fort Benton, Montana; see -ITE1]

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      clay formed by the alteration of minute glass particles derived from volcanic ash. It was named for Fort Benton, Mont., near which it was discovered.

      The formation of bentonite involves the alteration of volcanic glass to clay minerals; this requires hydration (taking up or combination with water) and a loss of alkalies, bases, and possibly silica, with the preservation of the textures of the original volcanic glass. Bentonite consists chiefly of crystalline clay minerals belonging to the smectite group, which are hydrous aluminum silicates containing iron and magnesium as well as either sodium or calcium. Two types of bentonite are recognized, and the uses of each depend on specific physical properties.

      Sodium bentonites absorb large quantities of water, swelling to many times their original volume, and give rise to permanent suspensions of gellike masses. These have been used to seal dams; in bonding foundry sands, asbestos, and mineral wool; as drilling muds; in portland cements and concrete, ceramics, emulsions, insecticides, soaps, pharmaceuticals, and paints; in the manufacture of paper; for clarifying water, juices, and liquors; and as a water softener to remove calcium from hard water. Calcium bentonites are nonswelling and break down to a finely granular aggregate that is widely used as an absorbent clay sometimes called fuller's earth.

      Bentonite occurs in rocks that were deposited in the Ordovician to Tertiary periods (about 505 to 1.6 million years ago). In the United States the principal producers are Wyoming, Montana, California, Arizona, and Colorado. Important world producers are Greece, Japan, Italy, Brazil, Romania, Germany, Mexico, Argentina, Spain, India, Hungary, Poland, Canada, Turkey, and Cyprus.

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Universalium. 2010.

Look at other dictionaries:

  • Bentonite — is an absorbent aluminium phyllosilicate generally impure clay consisting mostly of montmorillonite. There are a few types of bentonites and their names depend on the dominant elements, such as K, Na, Ca, and Al. As noted in several places in the …   Wikipedia

  • Bentonite — La bentonite est une argile colloïdale dont le nom vient de Fort Benton dans le Wyoming aux États Unis. Connue aussi sous le terme de terre à foulon, elle peut être considérée comme une smectite, étant essentiellement constituée de… …   Wikipédia en Français

  • bentonite — [ bɛ̃tɔnit ] n. f. • 1928; de Fort Benton, n. d une ville des États Unis ♦ Géol. Minéral argileux gonflant au contact de l eau. ● bentonite nom féminin (de Fort Benton, nom propre) Argile smectique gonflante de la famille des montmorillonites.… …   Encyclopédie Universelle

  • bentonite — entonite n. an absorbent aluminum silicate clay formed from volcanic ash. [WordNet 1.5] …   The Collaborative International Dictionary of English

  • Bentonite — Bentonite. См. Бентонит. (Источник: «Металлы и сплавы. Справочник.» Под редакцией Ю.П. Солнцева; НПО Профессионал , НПО Мир и семья ; Санкт Петербург, 2003 г.) …   Словарь металлургических терминов

  • bentonite — ☆ bentonite [ben′tən īt΄ ] n. [after Fort Benton (named for Senator Benton: see BENTON Thomas Hart) in Montana, where it is found] a porous clay consisting mainly of the mineral montmorillonite, which swells greatly when it absorbs water …   English World dictionary

  • bentonite — ben·to·nì·te s.f. TS petr. → argilla smectica {{line}} {{/line}} DATA: 1942. ETIMO: dall ingl. bentonite, der. di (Fort) Benton, nome di una località del Montana …   Dizionario italiano

  • bentonite — bentonitas statusas T sritis chemija apibrėžtis Montmorilonitinis molis, kurio pagrindinis komponentas hidratuoti aliuminio silikatai. atitikmenys: angl. bentonite rus. бентонит …   Chemijos terminų aiškinamasis žodynas

  • Bentonite —    La bentonite est une argile que l on utilise pour coller les vins, c est à dire pour les clarifier, les rendre limpides …   L'Abécédaire du Vin

  • bentonite — noun Etymology: Fort Benton, Mont. Date: 1898 an absorptive and colloidal clay used especially as a sealing agent or suspending agent (as of drugs) • bentonitic adjective …   New Collegiate Dictionary

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