Ball Clay
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. They are commonly used in the construction of many ceramic articles, where their primary role, apart from their white colour, is to either to impart plasticity or to aid rheological stability during the shaping processes.
Application of the product :
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.
Sanitary-ware :
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 the 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.