The Properties and Applications of Bentonites
Abstract
Bentonite, a naturally occurring clay mineral composed mainly of montmorillonite, exhibits distinctive properties such as swelling capacity, cation exchange, and colloidal stability. These characteristics make it one of the most versatile industrial minerals. Formed through the alteration of volcanic ash, bentonite occurs in two primary types: sodium bentonite, with high swelling ability, and calcium bentonite, with greater structural stability. This distinction directly influences its wide-ranging applications. In petroleum drilling, sodium bentonite is indispensable for stabilizing boreholes and forming drilling muds, while in foundries it ensures mold integrity at high temperatures. In civil engineering, it serves as a barrier in slurry walls and dam construction, and in environmental protection it acts as a natural liner to prevent contamination. Calcium bentonite contributes to agriculture by improving soil fertility and water retention, while both types are used in pharmaceuticals and cosmetics for their absorbent and non-toxic qualities. Recent studies also highlight bentonite’s potential in nanotechnology, renewable energy, and pollutant remediation. Its abundance, sustainability, and adaptability underline its ongoing industrial and ecological significance.