The existence of Kaolin has extraordinary functions in meeting various human needs. This versatile mineral has been applied in many industries due to its unique chemical and structural properties. To learn more about the uses of Kaolin in various fields, continue reading this blog of TKC Vietnam.
What is Kaolin?
Kaolin is primarily composed of the mineral kaolinite. Depending on its source and formation, kaolin may also contain other minerals such as muscovite, quartz, feldspar, and anatase. Although kaolin is naturally bright white, it can sometimes have yellow or rust-colored stains due to exposure to iron oxides.
Chemistry and structural composition of Kaolin
Before explaining the chemical composition and structural properties of kaolin, let us first understand its formula and formation process.
Kaolinite Chemistry: In its natural kaolinite mineral state, the chemical formula of kaolinite is Al2Si2O5(OH)4. Kaolinite is an aluminium silicate mineral that develops through the chemical weathering of aluminium-rich feldspars found in granites and pegmatites.
Structure: The kaolin composition consists of hexagonal crystals ranging in size from 0.1 to 10 micrometers. These crystals form in stacked layers and this kaolinite structure partly gives the clay its desirable properties.
Due to the chemical composition and structure of kaolin, its natural properties are highly sought after for industrial use.
Chemically Inert: Kaolin has a neutral pH, making it ideal for use in pharmaceuticals, cosmetics, and industrial blends because it does not alter the chemical composition of the product or promote bacterial growth.
Adsorbent: One of the main uses of kaolin clay is to aid in the adsorption of other substances. Kaolin clay has a high natural adsorption capacity, so it can help extract and remove unwanted impurities, pathogens, or other substances in any blend or application.
Non-swelling: Between each layer of kaolinite crystals are hydrogen bonds that prevent water molecules from penetrating the layers. This ability to prevent water from penetrating the crystal structure of kaolin gives it the property of non-swelling. Non-swelling is a valuable property of additives such as kaolin, as they do not alter the physical properties of the blend or product in question.
