Universal clay, also known as bentonite, is a hydrous clay mineral primarily composed of montmorillonite. It possesses many unique properties, such as swelling, adhesion, adsorption, catalysis, thixotropy, suspension, and cation exchange. It is a highly advantageous non-metallic mineral and is widely used in industrial and agricultural production, including foundry, metallurgy, food, and chemical industries.
Bentonite is also used as a mud constituent for oil and water well drilling. Its roles are mainly to seal the borehole walls, to remove drill cuttings, and to lubricate the cutting head.
Universal clay (bentonite) is a non-metallic mineral primarily composed of montmorillonite. Montmorillonite has a 2:1 crystal structure consisting of two silicon-oxygen tetrahedra sandwiching a layer of aluminum-oxygen octahedra. Because the layered structure of the montmorillonite unit cell contains certain cations, such as Cu, Mg, Na, and K, these cations interact very unstablely with the montmorillonite unit cell and are easily exchanged for other cations, resulting in excellent ion exchange properties.
