Ball clays are kaolinitic sedimentary clays and usually contain three dominant minerals: from 20-80% kaolinite, 10-25% mica, and 6-65% quartz. It is light to white in colour and on firing may range from white buff. The main utility of ball clay lies in its high plasticity. The wide use of ball clay is mainly due to its contribution of workability, plasticity and strength to the bodies in drying. Ball clay, on the other hand, also imparts high-drying shrinkage which is accompanied by a tendency towards warping, cracking and sometimes even dunting.
Uses :
Ceramic : A ‘ceramic body’ for sanitary-ware typically includes 30% ball clay to provide plasticity and workability.
Refractories : 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 used in the electrical porcelain components provide insulation from high voltage currents.
Non-ceramic applications: These include the construction industry; horticulture, agriculture and amenity industries; use as fillers and extenders in polymers, adhesives, plastics, sealants, fertilizers and insecticides.
