The Ball clay is an extremely rare mineral found in very few places around the world. Its name dates back to the early methods of mining when specialized hand tools were used to extract the clay in rough cube shapes of about 30 cm. As the corners were knocked through handling and storage these cubes became rounded and ball shaped. It also is sometimes referred to as plastic clay. Ball clays are sedimentary in origin. Ancient rivers and streams washed kaolinite (formed from decomposed granite) from its parent rock. As the streams flowed from upland area they mixed with other clay minerals, sands, gravels and vegetation before settling in low-lying basins to form overlaying seams of ball clay. Ball clays usually contain three dominant minerals: from 20-80% kaolinite, 10-25% mica, and 6-65% quartz. In addition, there are other 'accessory' minerals and some carbonaceous material (derived from ancient plants) present. The wide variation both in mineral composition and in the size of the clay particles results in different characteristics for individual clay seams within a deposit Ball clay is a secondary or transported type of clay that is found in stratified layers, often alternating with layers of coal and with other types of clay. It is highly plastic. Although not so pure as kaolin, ball clay is relatively free from iron and other mineral impurities and burns to a light gray or light buff color. It tightens into a dense structure when fired to about 1800 degree, Different ball clays vary considerably in composition. Ball clays are impossible to use alone in pottery because of their excessive shrinkage, which may be as high as 20 percent when fired to maturity. They are usually used as an admixture to other clays to gain increased plasticity and workability. In manufacturing whitewares, ball clay is indispensable as an addition to the body to overcome the nonplastic properties of kaolin. However, if whiteness is desired, not more than about 15 percent of ball clay can be added to a clay body; more than this amount in a whiteware body results in a gray, off-white, or buff color. The presence of ball clay in a porcelain body decreases its translucence.
A Vital Material in Ceramics
Ball Clays are used in many different industries, but in particular form a vital component in ceramic manufacturing. Kaolin ("china clay") produces a very white color when it is fired, but used alone it is brittle and weak and must be mixed with ball clay to produce a workable, malleable raw material. As a result of their sedimentary origin, raw ball clays have a wide range of colors. However, many of them are valued by the ceramics industry for their white-firing properties, which are determined by the levels of iron and other coloring/fluxing oxides within the clay
Sanitaryware
A Ceramic body for sanitaryware typically includes 30% ball clay to provide plasticity and workability, 20% kaolin, 30% feldspar and 20% quartz/silica.
Tableware
Ceramic tableware utilizes ball clay to provide high plasticity and a good white-fired color, combined with kaolin, feldspar and quartz
Wall and Floor Tiles
Combined with talc, feldspar, quartz/silica and kaolin, ball clays are utilized for their plasticity and bonding properties
Glazes and Engobes
Ball clays are also used in the production of coatings for ceramic products to ensure perfect finish.
Refractory clays
An ability to resist the effects of extremely high temperatures makes ball clay ideal for use in refractory products such as kiln insulation and furniture.
Construction ceramics
Building materials such as bricks, clay pipes and roof tiles all contain ball clay.
Electrical Porcelain Insulators
Ball Clays are found in the electrical porcelain components that provide insulation from high voltage currents
Non-ceramic applications
These include the construction industry; horticulture, agriculture and amenity industries; used as fillers and extenders in polymers, adhesives, plastics, sealants, fertilizers and insecticides.
Powder
Ball Clay Can be grinned into powder form in various sizes generally as Mesh (#) 200#, 250# So On.
