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 ?
Among the whole studied alumosilicates the sample of kaolinite from Russian deposit, containing also 30 % of hydromica and 10 % of montmorillonite, provided relatively high conversion of MBOH, which, at the same time, did not exceed the one provided by palygorskite.
Montmorillonite was found to present a higher density than zeolite.
Two layered silicate fillers were used in this study: the natural montmorillonite MNa and the modified "Bentonite for water systems" (BW), which were to be further compatibilized by treatment with suitable organic compounds.
The low values of K in areas like Akim Asubua (near Caana), Akim Abenase, Akim Asubua and Adawso I (Mile 42) I, contained montmorillonite could be attributed to these areas experiencing excessive rainfall; and thus Barber (1960) [13] reported that areas receiving low rainfall conditions had low available K.
Efficacy of montmorillonite clay (NovaSil Plus) for protecting fullterm broilers from aflatoxicosis.
The acid (using HCl) treated montmorillonite was procured from Ashapura Minechem Ltd.
The FTIR spectrum related to the incorporation of montmorillonite in the film (Figure 1d.), shows that the vibrations at 468 and 802 [cm.sup.-1], which are characteristic of montmorillonite [19] (Figure 1e.) related to Si-OSi bending and the presence of amorphous silica, respectively, are visualized in the spectrum of the SG-m film, suggesting that the clay is dispersed in the polymer matrix of this film, as expected.
Bentonite clay consists of 85% Montmorillonite Al2Si4O10(OH)2nH2O that belongs to Semectite group [10, 11].
Among these nanofillers, carbon nanotubes (CNTs) and montmorillonite (MMT) have shown attractive fillers in tire tread compounds because they improve the tread grip and rolling resistance performance of the compound at low temperature [16, 17].
Smectite is the name used for a group of phyllosilicate mineral species, the most important of which are montmorillonite, beidellite, nontronite, saponite, and hectorite [4].
This is not true in the case of LS, which gained their "nano" prefix with the introduction of polymer nanocomposites or polymer layered silicates (PLS) in 1985 at Toyota Central R&D Labs Inc., when Nylon-6 was mixed with montmorillonite (MMT).
Therefore, kaolinite and montmorillonite clays that cover the typical range of the plasticity index have been chosen as "parent materials." Kaolinite, having a plasticity index of 11%, represents the lower end of the plasticity scale.