Calcium Bentonite

Calcium bentonite is a southern-style montmorillonite bond clay used in green sand molding systems for aluminum, brass, bronze, and other non-ferrous castings where fast mull response, high green strength, and good permeability are important.

Compared with sodium bentonite, calcium bentonite swells less, absorbs less water, and activates more quickly, which can improve mold flow and shakeout while still delivering a strong green bond. Many foundries also blend it with sodium bentonite to balance green strength, hot strength, and erosion resistance for their specific sand system.