bentonitok

Bentonite is a type of clay, primarily composed of montmorillonite, a mineral from the smectite group. Its name derives from the Fort Benton Group in Wyoming, where it was first discovered. Bentonite is formed by the weathering of volcanic ash, often in the presence of water. The defining characteristic of bentonite is its ability to absorb large amounts of water, causing it to swell significantly. This swelling is due to the layered structure of montmorillonite, where water molecules can intercalate between the clay sheets.

The properties of bentonite, particularly its plasticity, viscosity, and thixotropy (the ability to become fluid when agitated and then return to a gel-like state), make it useful in a wide range of applications. It is commonly used in drilling muds for oil and gas exploration, where it helps to lubricate the drill bit and carry cuttings to the surface. In construction, bentonite is used for slurry walls, waterproofing, and as a sealant in landfills. It also finds use in foundry molds, as a clarifying agent for wine and oils, and in cosmetics and pharmaceuticals due to its absorbent and binding properties. The specific properties and applications can vary depending on whether the bentonite is sodium-based or calcium-based, with sodium bentonite generally exhibiting greater swelling capacity.