Montmorillonite


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montmorillonite

[‚mänt·mə′ril·ə‚nīt]
(mineralogy)
A group name for all clay minerals with an expanding structure, except vermiculite.
The high-alumina end member of the montmorillonite group; it is grayish, pale red, or blue and has some replacement of aluminum ion by magnesium ion.
Any mineral of the montmorillonite group.

Montmorillonite

 

(named after the French city Montmorillon in Vienne Department), a clay mineral of the lamellar silicate subclass. It has a variable chemical composition, (Ca, Na)(Mg, Al, Fe)2[(Si, Al)4O10] (OH)2nH2O. Its structure is characterized by the symmetrical arrangement of lamellar aggregates (as in pyrophyllite). Interlaminar water molecules and atoms constituting exchange bases (for example, Ca and Na) are distributed between the pyrophyllite sheets. The lamellar aggregates are located at a considerable distance from each other. The mineral forms compact argillaceous masses. Monoclinic crystals rarely occur and can be seen only through an electron microscope; irregular sheets are most commonly observed.

Montmorillonite is white, pink, blue-gray, brown, red, or green, depending on the admixture content. Its hardness on Mohs’ scale is approximately 1, and its density is about 1,800 kg/m3. When wet, the mineral swells considerably as the water penetrates the interlayer spaces.

Montmorillonite is a typical product of aluminosilicate erosion under alkaline environmental conditions. It is the dominant mineral in bentonite and is present in soil, detrital loam, and other sedimentary rocks. Montmorillonite is an extremely valuable mineral. It is an active component of bleaching clay and fuller’s earth, which are used in the petroleum, textile, and soap industries for their adsorptive and saponifying properties.

V. P. PETROV

montmorillonite

One of the common clay minerals which typically swells upon wetting and becomes soft and greasy.
References in periodicals archive ?
Natural montmorillonite particles with average size of 12 [micro]m were used as inorganic solid stabilizer for styrene in water.
Faded emerging of montmorillonite in Maroon oil field can be considered due to marine condition or to convert a part of it to Illite.
Keren R, Talpaz H (1984) Boron adsorption by montmorillonite as affected by particle size.
Evaluations confirmed that the diameter of titanium dioxide nanoparticles has decreased from 70 to 50 nm after the stabilization on montmorillonite particles.
Use of methylene blue and crystal violet for determination of exchangeable cations in montmorillonite.
The montmorillonite used in this study was purchased from the Zhejiang Sanding Technology Company (Zhejiang, China).
Zaarei, D, Sarabi, AA, Sharif, F, Moazzami Gudarzi, M, Kassiriha, SM, "Using of p-Phenylenediamine as Modifier of Montmorillonite for Preparation of Epoxy-Clay Nanocomposites: Morphology and Solvent Resistance Properties.
Wettability of montmorillonite clays in humic acid solutions.
Herrera (1958) [12] on the basis of montmorillonite being the constituent which fixes K most strongly suggested that the percentage of montmorillonite in a soil could be used as an index of its potassium-fixing capacity.
The etherification of alkanes with different nucleophiles in the presence of metal-ion-exchanged montmorillonite clay catalysts were successfully demonstrated by Ballantine et al [8].
A sampling of topics: embed geodesic cycles into Mobius cubes, adaptive wavelength assignment scheme for distributed path restoration in optical networks, study of a new series hybrid active power filter, efficient provable secure ID-based anonymous signcryption scheme, a thermal study of porous Si-pillared montmorillonite with high surface area, and performance modeling of composite web services.
Montmorillonite is a derivative of volcanic ash, so it may have been available on early Earth where volcanic eruptions were common, the researchers say.