Bentonite is used as a binding agent in making molding sands for use in iron, steel and non-ferrous casting. The unique properties of bentonite yield green sand molds with good flowability, compactability and thermal stability for the production of high quality castings. It is also used in the production of copper base and aluminum castings when extra performance is needed. Bentonite imparts excellent dried and fired strengths to molding sand where high temperature pouring occurs. Its unique capability to hold water prevents mold surface erosion by molten metal. Bentonite also provides excellent strength and toughness to molding sand mixtures, enabling good draw of the pattern.
The use of bentonite enables foundries to reduce their waste from metal casting defects and improve their recycling efficiency for mold sand systems.