Calcined kaolin is a key component of many industrial processing processes and products. Because kaolin exhibits so much variability in its raw state, it is important to work with a professional calcination expert to make sure the final product meets your specifications. Calcination is a relatively well-established thermal process, but its results can vary. Because of this, testing is critical for achieving the precise characteristics that you need.
After kaolin is harvested from nature, it undergoes a calcination process to remove the impurities and increase its optical properties. This process, also called calcination, removes water and dehydroxylizes kaolinite and crystallizes metakaolinite, which gives it a bright white color and improves its optical properties. Calcined kaolin is then used in paints, ceramics, and polymer applications.
Calcination can be carried out by heating kaolin to a certain temperature. This process removes both chemically bound moisture and free moisture. Calcination is done using different methods, but usually occurs between 400 and 600 degrees Celsius. The resulting product, called metakaolin, is widely used as a supplementary cementitious material. It can replace cement clinker in many applications.
Calcined kaolin is an excellent reinforcing filler, improving mechanical properties, and the appearance of concrete. It is also an excellent source of alumina for the production of fiberglass and plastics. It also acts as a natural opacifier. Moreover, it is a good partial replacement for titanium dioxide in some applications.
Calcined kaolins are also used in glazes and slips. The high clay content in calcined kaolins allows them to substitute raw kaolin in glazes without losing their fired properties. Calcined kaolin has a high degree of refractoriness and is often used in refractory castables and low expansion clay bodies.
Calcined kaolin is more expensive than hydrous kaolin. However, it is also more suitable for paints and ceramics. It is a superior extension agent than hydrous kaolin, which is used as a filler in paints. Calcined kaolin is also more resistant to scrubs.
Calcined kaolin has a high percentage of alumina and silica and is an excellent alternative to raw kaolin. While calcining clay may add a bit more work to your process, it gives you more control over the properties of the finished glaze. This makes it an excellent option for many applications.
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