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Sodium Bentonite Uses

Sodium bentonite is a naturally occurring clay rich in aluminum silicate which has a soft, slippery texture and high water absorbency properties. Its color ranges from white to green, but changes to yellow to brown when removed from the ground and in contact with oxygen. According to researcher Kittitep Fuenkajor in "Sealing Of Boreholes And Underground Excavations In Rock," common uses of sodium bentonite include water retention applications, metal casting molds and pellets.

Water Retention Applications
- Sodium bentonite is used in civil engineering as a waterproof substance, hydrated and mixed with cement and other minerals. When hydrated, sodium bentonite swells, forming a low permeability layer, which is also ideal for applying on ponds, sanitary and industrial landfills, reservoirs, dams and lagoons, according to Kittitep Fuenkajor in "Sealing Of Boreholes And Underground Excavations In Rock."
Metal Casting Molds
- The foundry industry uses sodium bentonite as a bonding agent in the production of molds. Sodium bentonite is mixed with sand and water, creating a plastic material that is compressed around a pattern to create a mold. Sodium bentonite molds are resistant to molten metals and can withstand temperatures of up to 3,000 degrees Fahrenheit, according to Kittitep Fuenkajor.
Pelleting
- Pelleting is the process of compressing a material into small particles (pellets). Sodium bentonite is used as a binding agent in this process, often in animal feeds, iron ore and other finely grained solids, reports Kittitep Fuenkajor. The use of sodium bentonite to pellet iron ore started in the middle 1950s. Today, the pelleting iron ore is among the most common uses for sodium bentonite.

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