Bentonite, also known as bentonite clay or montmorillonite clay, is a naturally occurring clay mineral primarily composed of montmorillonite. It is renowned for its exceptional water absorption, swelling properties, and cationic exchange capacity. The name “Bentonite” originates from the Benton area of Wyoming, USA, where this unique clay mineral was first discovered and named in honor of its discovery site.

Bentonite is characterized by its ability to form gels when hydrated, which makes it highly valuable in various industries. Its physical and chemical properties enable it to be used as a key component in drilling muds, enhancing their viscosity, suspension, and lubricity. In the paper industry, bentonite serves as a filler and coating agent, improving paper whiteness, smoothness, and printability. Additionally, it finds applications in metallurgy, ceramics, cosmetics, and more, where it may be required in different forms and with specific performance requirements.

The color of bentonite can range from white and pale yellow to various shades including gray, green, pink, brown, and red, depending on its iron content. It often exhibits a waxy, earthy, or greasy luster and can be found in both loose and compact forms. The adsorption capacity of bentonite is significantly influenced by its particle size, with finer particles demonstrating stronger adsorption.