Bentonite

Bentonite is a naturally occurring clay primarily composed of montmorillonite minerals noted for their swelling properties when wet. It is supplied as a fine grey to cream powder with a typical pH range from 6 to 10 when dispersed at 5%. This mineral’s unique ability to absorb water and expand up to several times its dry volume makes it valuable in multiple industrial processes. Finstar offers bentonite with a standard chemical composition approximated by Al2H2Na2O13Si4, exhibiting water insolubility but significant swelling upon hydration. Procurement officers typically dose bentonite around 3-6% by weight in drilling fluids to optimize viscosity and stability, but specific rates depend on application requirements. It is incompatible with concentrated acids which degrade its structure and should be stored dry to maintain performance.

In drilling operations, maintaining borehole integrity is critical to project success and safety. Bentonite’s capacity to increase fluid viscosity and suspend drill cuttings prevents sediment settling and bore collapse, enabling continuous operations. Beyond drilling, bentonite facilitates water treatment by adsorbing impurities, and in foundries, it binds sand to form strong molds for metal casting. Its sealing ability in landfill liners reduces environmental contamination, underscoring its role in regulatory compliance and operational reliability.