a. Ball Clay
Ball Clay a member of kaolinite family, is renowned for its plasticity and green strength, and as such it forms a major part of many ceramic applications, including Sanitary ware, Tiles, Tablewares and to an increasing extent non-ceramic applications like functional fillers and advanced application for example technical ceramics.
They consist varying proportions of kaolinite, mica and quartz, with small amounts of organic matter and other minerals and commercially valuable because they increase the workability and strength of various ceramic bodies and have white or near white firing characteristics.
Ball Clay is processed to minimize the levels of coarse particles. This enhances better workability and higher strength.
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.
A ‘ceramic body’ for sanitaryware typically includes 30% ball clay to provide plasticity and workability, 20% kaolin, 30% feldspar and 20% quartz/silica.
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.
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.
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.
These include the construction industry; horticulture, agriculture and amenity industries; used as fillers and extenders in polymers, adhesives, plastics, sealants, fertilizers and insecticides.
Quartz is one of the most well – known minerals on the earth with numerous uses. Sand, which is composed of tiny quartz pebbles, is the primary ingredient for the manufacture of glass. It is also used as an abrasive for sandblasting, grinding glass and cutting of soft stones. Quartz powder is also used in ceramic tiles along with feldspar.
There are two entirely different major uses for quartz crystal. One of these is as a gemstone. The varieties known as rock crystal, amethyst, smoky quartz, rose quartz, and citrine are in demand as low-priced but attractive gemstone or display specimens. For gem applications, the quartz is usually cut and faceted for jewelry, or is carved into various shapes by hand or by laser.
Cultured quartz is used in electronic applications, where its special physical properties are valuable. Quartz is one of several minerals which are piezoelectric, meaning that when pressure is applied to quartz, a positive electrical charge is created at one end of the crystal and a negative electrical charge is created at the other. It is also strongly pyroelectric which means that temperature changes can cause the development of positive and negative charges within the crystal. These properties make quartz valuable in electronics applications. While some other minerals may have these properties, quartz is used because it is transparent, tough, and of unvarying chemical composition.
Electronics-grade manufactured quartz is used in a large number of circuits for consumer electronics products such as computers, cell phones, televisions, radios, and electronic games, to name just a few. It is also used to make frequency control devices and electronic filters that remove defined electromagnetic frequencies. In industry, quartz is also used in a variety of electronic devices.
Feldspar is non plastic potassium or sodium aluminosilicate mineral represented as KALSi3O8 or NaALSi3O8. Feldspar is used generally for three purposes:
It is used along with Ball Clay, Kaolin and Quartz for tiles and Sanitaryware manufacturing.
- Ceramic Manufacturing
- Glass Manufacturing
- Abrasive Manufacturing
The presence of Iron even in small quantity tends to impact coloration.
Feldspar is generally used :
The glass and ceramic industries are the major consumers of feldspar and account for 95% of the total consumption.
The proportion of Feldspar varies in different proportions in porcelain, china and earthenware. Earthenware contains on an average
In making the body composition of several types of procelain, china and earthenware and also in the preparation of glazes and enamel.
As an important ingredient in the glass sand batch.
As a bonding agent in the manufacture of bonded abrasives like wheels and discs of garnet, corundum, emery etc.
This proportion of feldspar varies in different products like
- 12% feldspar
- 25% ball clay
- 28% china-clay
- 35% quartz
- Wall tile -5%
- Floor tile -30%
- Statutory porcelain -50%
- Sanitary china and prodelain bodies -30%