Debate Kit

Bentonite is a remarkable and highly versatile absorbent clay, formed from the weathering of volcanic ash. Comprised predominantly of the mineral montmorillonite, its unique molecular structure gives it the ability to absorb water, swell significantly, and develop thixotropic (gel-like) properties, making it an indispensable material in a vast range of industrial applications. The global bentonite market is a large and diverse sector, with its demand stemming from its utility in everything from heavy industry and civil engineering to consumer goods and agriculture. The two main commercial types, sodium bentonite and calcium bentonite, offer distinct properties that cater to different end-uses, with sodium bentonite being known for its superior swelling capacity and calcium bentonite for its absorbent qualities.

The foundry and drilling industries are the largest consumers of bentonite. In metal casting, sodium bentonite is used as a bonding agent in green sand molds. When mixed with sand and water, it develops the necessary plasticity and strength to hold the shape of the mold during the pouring of molten metal. In the oil and gas and water well drilling sectors, bentonite is a crucial component of drilling mud. When mixed with water, it forms a viscous slurry that cools and lubricates the drill bit, carries rock cuttings to the surface, and, most importantly, forms a filter cake on the wall of the borehole to prevent fluid loss and maintain wellbore stability. Its thixotropic nature is key here, as it allows the mud to be fluid when pumped but to gel and hold cuttings in suspension when circulation stops.