What is Bentonite?

Definition
The term bentonite refers to clays or clay rock (very fine grain sediments or sedimentary rock), which primarily consists of the expandable mineral montmorillonite.

Formation
Montmorrillonite-rich clays have formed by weathering and metamorphose of volcanic ashes, tuff and basic rock (e.g. basalts). The term bentonite is derived from the first archaeological site near Fort Benton, Wyoming (USA), where plastic clays were found and described for the first time. There are numerous bentonite formations differentiated acc. to montmorillonite type, kind and location of formation and mineralogical composition.

Properties
Its exceptional properties – e.g. capability of expansion, absorption – are defined by the clay material montmorillonite. Due to its crystal structure (montmorillonite is a so-called layer silicate with expandable layers in the crystal), montemorillonite has the capability to absorb or deposit substances in its crystal grid, to partially exchange or fix them. Bentonite is capable to expand its volume by 6 times by water absorption and to form stable gels (gelatinous substance).

Fields of application
The main application domains and use of bentonite range from pet hygiene and pet food to foundries, oil drilling industry, agriculture, cosmetics industry.