Introduction of Kaolin
Kaolin is a clay mineral, part of the group of industrial minerals with the chemical composition Al2Si2O5(OH)4. It is a layered silicate mineral, with one tetrahedral sheet of silica (SiO4) linked through oxygen atoms to one octahedral sheet of alumina (AlO6) octahedra. Rocks that are rich in kaolinite are known as kaolin or china clay.
Application of Kaolin Powder
The primary use of kaolin is in the paper industry. It serves as a paper coating which improves appearance by contributing to brightness, smoothness and gloss. It also improves printability. Additionally, it is used by the paper industry as a filler reducing cost and the use of tree-based resources. The required particle size is at least 2μm D75 and content of 45 μm is no more than 0.05%.
Many people are under the mistaken impression that the only use for kaolin is in the manufacture of china. This is not true, and its use by the paper industry far exceeds its other uses. However, kaolin still serves as a valuable component in china and other tablewares. Its color, gloss and hardness are ideal characteristics for such products.The required particle size is at least 63μmD99.
The bonds between the kaolin and the polymers provide enhanced mechanical strength, improved impact and flex strength, and a high degree of hydrophobicity. Kaolin also acts as a titanium dioxide extender, which means less of the expensive additive is needed to yield sharper colors.
In rubber, kaolin performs as a processing aide, giving the material dependable curing rates and increased strength with better resistance to tears and abrasions. The required particle size of the kaolin powder is at least 125 μm D99.95
Paint and Coating Industry
Kaolin also offers increased opacity and tint strength, stain and scrub resistance, improved pigment suspension, sheen control and improved holdout.The required particle size of kaolin powder is at least 10μm D70.