Kaoliiniryhmään

Kaoliiniryhmään refers to a group of clay minerals belonging to the kaolin group. These minerals are primarily composed of kaolinite, dickite, nacrite, and halloysite. They are phyllosilicate minerals, meaning they have a layered structure. Kaolinites are hydrous aluminum silicates with the general formula Al2Si2O5(OH)4. The structure consists of a tetrahedral sheet of silica linked to an octahedral sheet of alumina.

Kaolin group minerals are known for their distinct physical properties, including softness, whiteness, and chemical inertness. They are typically formed by the chemical weathering of feldspar and other aluminum silicate minerals. This weathering process, known as kaolinization, occurs in the presence of water and carbon dioxide. The resulting clay deposits are often found in sedimentary rocks, but can also occur in residual deposits where the parent rock has been altered in situ.

The primary applications of kaolin group minerals are in the paper industry, where they are used as fillers and coating pigments to improve brightness, opacity, and printability. They are also utilized in ceramics, rubber, plastics, paints, and cosmetics. Due to their inertness and absorbent properties, they find use in pharmaceuticals and as a component in some antidiarrheal medications. The specific properties and purity of kaolin deposits determine their suitability for various industrial uses.