China Clay or Kaolin is one of the purest form of clays, composed chiefly of the mineral kaolinite, usually formed when granite is changed by hydrothermal metamorphism. Kaolinite is a clay mineral, part of the group of industrial minerals, with the chemical composition Al2Si2O5(OH)4. It is a layered silicate mineral, with one tetrahedral sheet of silica (SiO4) linked through oxygen atoms to one octahedral sheet of alumina (AlO6) octahedra.
Kaolinite has a low shrink - swell capacity and a low cation-exchange capacity (1–15 meq/100 g). It is a soft, earthy, usually white mineral (dioctahedral phyllosilicate clay), produced by the chemical weathering of aluminium silicate minerals like feldspar. In many parts of the world, it is colored pink-orange-red by iron oxide, giving it a distinct rust hue. Lighter concentrations yield white, yellow or light orange colors. Commercial grades of kaolin are supplied and transported as dry powder, semi-dry noodle or as liquid slurry.
Salient Features
Contributes in improving the chemical resistance, electrical properties and reduction in water absorption
Lowers the crack tendency in the finished products
Improves shock resistance as well as surface quality
Ball Clay is a variety of Kaolinite, like china-clay. It differs from china-clay in having high plasticity and less refractoriness. In chemical composition, ball and china clays do not differ greatly except that the former contains a larger proportion of silica. It has derived its name from the practice of removing it in the form of ball-like lumps from the clay pits in the UK.
Ball clays are kaolinitic sedimentary clays that commonly consist of 20-80% kaolinite, 10-25% mica, 6-65% quartz. Localized seams in the same deposit have variations in composition, including the quantity of the major minerals, accessory minerals and carbonaceous materials such as lignite. They are fine-grained and plastic in nature, and, unlike most earthenware clays, produce a fine quality white-coloured pottery body when fired, which is the key to their popularity with potters. Ball clays are relatively scarce deposits due to the combination of geological factors needed for their formation and preservation.
Silica sand is one of the most common varieties of sand found in the world. It is used for a wide range of applications. Silica sand is used in industrial processing, to make glass, as fill, and to create molds and castings.
Silica sand is produced by crushing sand stone or quartzite of open texture, and washing and garding it to yield requisite grain distribution. Silica flour is produced by crushing grinding and washing the high grade quartz, quartzite rocks or from white silica sand.
Salient Features
Silica Sandstone is moisture free, fritable & hard.
Grain size of the particles is variable.
Friable & mainly brown to grey in colour.
Quartz is the most abundant and most common mineral on the Earth. It is found in almost every geological environment and also it is at least a component of almost every rock type. It has a hexagonal crystal structure and is made of trigonal crystallized silica. It is most varied in terms of varieties, colors and forms.
The most important distinction between the types of quartz is that one is of macrocrystalline, which is individual crystal visible to the unaided eye, and the other is microcrystalline or cryptodrystalline varieties, aggregates of crystals visible only under high magnification. Chalcedony is the generic term for cryptocrystalline quartz. The transparent variety tends to be macrocrystalline and the cryptocrystalline varieties are either translucent or mostly opaque.
Salient Features
Clear (in pure form)
6-sided prism ending in 6-sided pyramid (typical)
It has a hardness of seven on the Mohs Scale which makes it very durable.
Potash Feldspar is a naturally occuring Potassium Alumino Silicate rock occurring in pegmatite bodies. Feldspar is used as a flux in ceramic and glass industries. It also adds strength to the body. Feldspar is a rare occurrence of extremely pure mineral free from mica. The chief impurities namely clay, and other foreign matter all occur as fine bodies below one mm.
It is used in many industries like Ceramics, Glass Industries, Pottery, Battery, lead-acid automotive, Beverage glass, Fluorescent light, Mirror Plate, ceramic, Polyvinylchloride (PVC) plastic pipe Sink, ceramic Television picture tube, Tile, Sanitary, bulb , tube light etc.
Salient Features
Best for Ceramic & Sanitary Ware Manufacturing - Application in both Glaze (K2O > 11.5%) & Body (K2O >10.5%) - gives White Firing Colour.
Glass Grades - better fluxing from K2O > 10% (total alkalies > 13%), Alumina > 17% for strength, Low Iron Fe2O3 at < 0.5%.
High Potash K2O >11% for Flux coated Welding Electrodes.
Soda Feldspar refers to group of Aluminum Silicate of sodium. The chief use of Feldspar is in the Ceramic and Glass Industries. Smaller quantities are used in the manufacturing of Tiles, Whiteware, and Sanitaryware. Other uses of Feldspar include Catalysts, Acid resistant and Decorative Stone as a flux or binding agent in certain scanning Soaps and artificial teeth.
In ceramic bodies, the main vitrifying (fluxing) agent is feldspar. The majority of white ware bodies contain good proportions of feldspar. It acts as a flux. In the ceramic industry, the flux is defined as that portion of the body which develops glass phase. This is provided mostly by feldspar. The amount of flux in a ceramic body should be only in such a proportion as to develop the desired amount of vitrification. If excess of flux is added, the fired body becomes very glassy and consequently, brittle.
Salient Features
It acts as a flux
It is the main vitrifying agent in ceramic bodies
Bentonite is a clay generated frequently from the alteration of volcanic ash, consisting predominantly of smectite minerals, usually montmorillonite. It is an absorbent aluminium phyllosilicate clay consisting mostly of montmorillonite.
The term Bentonite was first used for a clay found in about 1890 in upper cretaceous tuff near Fort Benton, Montana. The main constituent, which is the determinant factor in the clay's properties, is the clay mineral montmorillonite. This in turn, derives its name from a deposit at Montm
Salient Features
Color: Light gray to off-white with pH value: 8.3 - 9.1
Odorless & Non-staining
Velveteen feel to touch
China Clay is a clay mineral with the chemical composition AlSiO3O5(OH)3. It is layered silicate mineral. It is soft earthy, usually white in color, produced by the chemical weathering of Aluminium Silicate mineral like Feldspar. Commercial grades of China Clay are supplied and transported as dry powder form, semi dry noodle form or as slurry.
Applications:
- It is used in Cer/bamics for body & glazing of Tiles and Sanitary Wares.
- In paper it is used as filler. It is also used for paper coating purpose.
- It is used in paint also to extend Titanium Dioxide (TiO2) and modify gloss level.
- It is used in rubber to enhance reinforcement properties.
