Pure China Clay is generally white in colour but it is also available in different colours like red blur and brown. China clay minerals do not posses any lustre it is dull and earthy in look. China clay is used as a food additive, in ceramics, medicine, coated paper, in toothpaste, cosmetics, etc. It is also used as a light diffusing material in white incandescent light bulbs. We are famous as the best among the china clay manufacturers as well as suppliers in India. Clay is a naturally occurring material composed primarily of fine-grained minerals, which show plasticity through a variable range of water content, and which can be hardened when dried andor fired. Clay deposits are mostly composed of clay minerals (phyllosilicate minerals), minerals which impart plasticity and harden when fired andor dried, and variable amounts of water trapped in the mineral structure by polar attraction. Organic materials which do not impart plasticity may also be a part of clay deposits. Clay minerals are typically formed over long periods of time by the gradual chemical weathering of rocks (usually silicate-bearing) by low concentrations of carbonic acid and other diluted solvents. These solvents (usually acidic) migrate through the weathering rock after leaching through upper weathered layers. In addition to the weathering process, some clay minerals are formed by hydrothermal activity. Clay deposits may be formed in place as residual deposits, but thick deposits usually are formed as the result of a secondary sedimentary deposition process after they have been eroded and transported from their original location of formation. Clay deposits are typically associated with very low energy depositional environments such as large lake and marine deposits. DefinitionClays are distinguished from other fine-grained soils by various differences in composition. Silts, which are fine-grained soils which do not include clay minerals, tend to have larger particle sizes than clays, but there is some overlap in both particle size and other physical properties, and there are many naturally occurring deposits which include both silts and clays. The distinction between silt and clay varies by discipline. Geologists and soil scientists usually consider the separation to occur at a particle size of 2 m (clays being finer than silts), sedimentologists often use 4-5 m, and colloid chemists use 1 m Geotechnical engineers distinguish between silts and clays based on the plasticity properties of the soil, as measured by the soils' Atterberg Limits. ISO 14688 grades clay particles as being smaller than 0.063 mm, and silts larger. Primary clays, also known as kaolins are located at the site of formation. Secondary clay deposits have been moved by erosion and water from its primary location. Depending upon academic source, there are three or four main groups of clays: kaolinite, montmorillonite-smectite, illite, and chlorite. Chlorites are not always considered a clay, sometimes being classified as a separate group within the phyllosilicates. There are approximately thirty different types of "pure" clays in these categories, but most "natural" clays are mixtures of these different types, long with other weathered minerals. Varve (or varved clay) is clay with visible annual layers, formed by seasonal differences in erosion and organic content. This type of deposit is common in former glacial lakes. Quick clay is a unique type of marine clay indigenous to the glaciated terrains of Norway, Canada and Sweden. It is a highly sensitive clay, prone to liquefaction, which has been involved in several deadly landslides. Historical and modern uses Clay layers in a construction site. Dry clay is normally much more stable than sand with regards to excavations. Clays exhibit plasticity when mixed with water in certain proportions. When dry, clay becomes firm and when fired in a kiln, permanent physical and chemical reactions occur which, amongst other changes, causes the clay to be converted into a ceramic material. It is because of these properties that clay is used for making pottery items, both practical and decorative. Different types of clay, when used with different minerals and firing conditions, are used to produce earthenware, stoneware and porcelain. Early humans discovered the useful properties of clay in prehistoric times, and one of the earliest artifacts ever uncovered is a drinking vessel made of sun-dried clay. Depending on the content of the soil, clay can appear in various colors, from a dull gray to a deep orange-red. Clay tablets were used as the first writing medium, inscribed with script through the use of a blunt reed called a stylus. Clays sintered in fire were the first form of ceramic. Bricks, cooking pots, art objects, dishware and even musical instruments such as the ocarina can all be shaped from clay before being fired. Clay is also used in many industrial processes, such as paper making, cement production and chemical filtering. Clay is also often used in the manufacture of pipes for smoking tobacco and marijuana. Clay, being relatively impermeable to water, is also used where natural seals are needed, such as in the cores of dams, or as a barrier in landfills against toxic seepage ('lining' the landfill, preferably in combination with geotextiles). Recent studies have been carried out to investigate clay's adsorption capacities in various applications, such as the removal of heavy metals from waste water and air purification. GeneralCategory : Mineral Chemica Formula : Al2Si2O5(OH)4 IdentificationColor : White, sometimes red, blue or brown tints from impurities Crystal Habit : Earthy Crystal System : Triclinic Cleavage : Perfect on 001 Fracture : Perfect Mohs Scale Hardness : 2 - 2.5 Luster : Dull and Earthy Refractive Index : 1.553 - 1.565, 1.559 - 1.569, 1.569 - 1.570 Streak : White Specific Gravity : 2.16 - 2.68 The chemical composition of Al2Si2O5(OH)4. It is a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina octahedra . Rocks that are rich in kaolinite are known as china clay or kaolin. UsesChina clay is used in ceramics, medicine, coated paper, as a food additive, in toothpaste, as a light diffusing material in white incandescent light bulbs and in cosmetics. It is also used in paint to extend titanium dioxide (TiO2) and modify gloss levels in rubber for semi-reinforcing properties and in adhesives to modify rheology. The largest use is in the production of paper, including ensuring the gloss on some grades of paper. Commercial grades of kaolin are supplied and transported as dry powder, semi-dry noodle or as liquid slurry. A more recent, and more limited, use is as a specially formulated spray applied to fruits, vegetables, and other vegetation to repel or deter insect damage. China clay can contain very small traces of uranium and thorium, and is therefore useful in radiological dating. While a single magazine made using kaolin does not contain enough radioactive material to be detected by a security-oriented monitor, this does result in truckloads of high end glossy paper occasionally tripping an overly-sensitive. China ClayWhen heated to between 650C and 900Cchina clay dehydroxylates to form Metakaolin. According to the American National Precast Concrete Association this is a supplementary cementitious material (SCM), when added to a concrete mix Metakaolin affects the acceleration of Portland cement hydration when replacing Portland cement by 20 percent by weight.
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