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 ?
Phase PDF No Clay material quartz 010-85-0794/010-85-0796 33,6 kaolinite 010-78-1996 19,3 muscovite 010-73-9865 6,6 hematite 010-73-0603 1,0 microcline 010-71-0955/010-76-1238 1,0 anatase 010-83-2243 2,0 calcite 010-72-4582 -- anorthite 010-73-0264 -- amorphous -- 36,5 and other Phase % weight Limestone Chamotte quartz 34,1 3,2 kaolinite -- -- muscovite -- -- hematite 1,3 -- microcline 3,4 -- anatase -- -- calcite -- 75,1 anorthite 6,8 -- amorphous 54,4 21,7 and other Table 2.
cations and their fixation on the edge of the kaolinite particles.
Very limited information has been reported regarding the effects of kaolinite supplementation on site and extent of digestions of steers fed high-grain finishing diets.
3b revealed the evidence of 4-NP interactions with AKC due to spectral changes and shift of prominent peaks from 3460 cm-1 to 3446 cm-1 due to phenolic O-H vibration stretching and also shifting of prominent kaolinite vibrations were observed at 1008 cm-1, 1031 cm-1 and 1105 cm-1 due to C-N stretching.
The expansion of illite and chlorite upon contacted with water was feeble, and kaolinite was not easily hydrated (Cui, D.
After heat treating and HCl leaching, most of the quartz phase remained, the peaks assigned to kaolinite were no longer distinguished anymore, as shown in Figure 2, which correlates with a degradation of Al/Si compounds, the peaks belonging to iron mineral of siderite were getting weaker, especially at 750[degrees]C and 850[degrees]C treatments, which indicates an effective removal of Fe and Al compounds from the coal gangue, and most of the silicon phases were still retained.
For oil shale with lower oil yield and lower calorific value, the program to be developed should foresee production of high-strength and energy-saving building ceramics, while the fire-resistant properties of kaolinite in oil shale as well as abundant pores produced through the combustion of organic matter could be fully made use of.
53 Mineralogy Content Kaolinite, Muscovite, None Gibbsite and Quartz Heavy Metals Content (mg/L) i) Chromium, Cr 0.
Kaolinite brightness can be modified by several methods such as fractionation by centrifuge or sedimentation process, (7) chemical bleaching, (8) intercalation (9,10) and calcination or thermal treatment.
The objective of this study was to determine the MPAC in five highly weathered soils and to establish relationships with (i) the pedogenic Fe oxides content, (ii) the concentrations of specific phases of Fe oxides (goethite, hematite, maghemite and ferrihydrite), (iii) the proportions of gibbsite and kaolinite and (iv) the specific surface area of these soils.
The company has also completed projects in lignite, kaolinite, non-metallic minerals and non-ferrous metals.