kaolinite


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Related to kaolinite: Illite, Montmorillonite

kaolinite

(kā`əlĭnīt), clay mineral crystallizing in the monoclinic system and forming the chief constituent of china claychina clay,
one of the purest of the clays, composed chiefly of the mineral kaolinite usually formed when granite is changed by hydrothermal metamorphism. Usage of the terms china clay and kaolin
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 and kaolin. It is a hydrous aluminum silicate commonly formed by the weathering and decomposition of rocks containing aluminum silicate compounds; feldspar is a chief source. Kaolinite has the same chemical composition as dickite and nacrite (both of which are also clay or kaolin minerals) but differs from them in origin, in optical properties, in reaction to heat, and in certain other physical properties. Kaolinite is the basic raw material for ceramics, and large quantities are also used in the manufacture of coated paper.

Kaolinite

 

a clay mineral from the group of hydrous aluminum silicates. Its chemical composition is Al4[Si4O10] (OH)8, and it contains 39. 5 percent Al2O3, 46.5 percent SiO2, and 14 percent H2O. Kaolinite forms earthen masses, in which, with high magnification under an electron microscope, small hexagonal crystals can be detected. It crystallizes in the monoclinic system. The mineral’s crystal structure is based on infinite sheets of Si—04 tetrahedrons, which have three common oxygens and are linked in pairs through the free apexes of the crystal lattice by the aluminum and hydroxyl. These sheets are interconnected by weak bonds and this determines the perfect cleavage of kaolinite as well as the possibility of the differing positioning of one layer on the other. This, in turn, leads to a certain change in the symmetry of the entire crystal structure. Kaolinite has a hardness of 1 on the mineralogical scale and a density of 2, 540–2, 600 kg/m3. It is greasy to the touch. In heating to 500°-600° C, it loses water, and at 1,000°-1, 200° C, it decomposes, liberating heat and forming initially sillimanite and then mullite. This reaction constitutes the basis of ceramic production.

A component of many clays, kaolinite is formed during weathering and hydrothermal alteration of feldspathic rock.

V. P. PETROV

kaolinite

[′kā·ə·lə‚nīt]
(mineralogy)
Al2Si2O5(OH)4 A common hydrous aluminum silicate mineral found in sediments, soils, hydrothermal deposits, and sedimentary rocks. It is a member of the kaolin group of minerals, which include dickite, halloysite, nacrite, ordered kaolinite, and disordered kaolinite.

kaolinite

One of the clay materials consisting of a hydrous aluminum silicate.
References in periodicals archive ?
The XRD results indicated that the clay assemblages of the Jiujiang sediments are mainly illite, kaolinite, vermiculite and HIV, with minor illite--vermiculite interstratified minerals and trace interstratified kaolinite minerals.
Tombacz E, Szekeres M (2006) Surface charge heterogeneity of kaolinite in aqueous suspension in comparison with montmorillonite.
Arditto (1983) suggested that much of the kaolinite matrix in the Pilliga Sandstone resulted from the post-depositional alteration of unstable detrital minerals by reaction with mobile groundwater.
Without a cation bridge, montmorillonite and kaolinite particles, both having permanent negative charge, would repel the negatively charged PAM molecules and thus form a more stable colloidal suspension.
The oil sand samples were identified having minerals which had become precipitated and occurred as pore filling cement; these included: sheet kaolinite, vermiform kaolinite and k--feldspar, pyrite crystal, corrosion quartz and corrosion feldspar.
Semi-quantitative estimation of clay mineral abundance Horizon Depth Kaolinite Smectite Illite (cm) (%) (%) (%) Floodplain, P1 Topsoil 0 4 75 23 3 Central horizons 4 23 67 32 1 Subsoil 23 60 71 28 1 Floodplain, P2 Topsoil 0-8 83 14 3 Central horizons 8-30 64 35 1 Subsoil 30-60 70 29 1 Low terrace, P4 Topsoil 0 16 81 17 2 Central horizons 16-62 94 5 I Subsoil 62-100 87 12 1 Low terrace, P5 Topsoil 0-11 85 13 2 Central horizons 11-51 91 8 1 Subsoil 51 100 67 32 1 Middle terrace, P7 Topsoil 0 60 82 17 1 Central horizons 60-108 72 26 1 Subsoil 108-160 75 23 1 Middle terrace, P8 Topsoil 0-62 41 58 1 Central horizons 62 107 47 52 1 Subsoil 107 160 58 40 2
The effect of kaolinite on the yield and composition of kukersite semicoking products.
Illite Vermiculite Kaolinite Chlorite % Fracture Face 70 <5 5 10 Till Matrix 70 10 5 5 Quartz Expandable Goethite % Fracture Face <5 10 0 Till Matrix <5 5 <5
X-ray microanalysis of these particles detected mainly oxygen/aluminum/silicon and oxygen/magnesium/silicon, compatible with kaolinite and talc, respectively.
To date over 500 samples of borehole material has been tested to determine their mineralogy, particularly for halloysite, kaolinite, illite-smectite levels and other properties.
Nucleation and growth history of zeolite LTA as-synthesized from kaolinite by two different methods, Appl.
For instance smectite soil, compared to kaolinite soil, tends to easily degrade as a result of swelling and dispersion of clay, leading to reduced infiltration and increased soil loss (Oster et al.