Sodium bentonite expands when wet, absorbing as much as several times its dry mass in water. Because of its excellent colloidal properties, it is often used in drilling mud for oil and gas wells and for geotechnical and environmental investigations.

The property of swelling also makes sodium bentonite useful as a sealant, especially for the sealing of subsurface disposal systems for spent nuclear fuel and for quarantining metal pollutants of groundwater. Similar uses include making slurry walls, waterproofing of below-grade walls, and forming other impermeable barriers, e.g., to seal off the annulus of a water well, to plug old wells, or to line the base of landfills to prevent migration of leachate. It is also used to form a barrier around newly planted trees to constrain root growth so as to prevent damage to nearby pipes, footpaths and other infrastructure.

Sodium bentonite can also be "sandwiched" between synthetic materials to create geo-synthetic clay liners (GCL) for the aforementioned purposes. This technique allows for more convenient transport and installation, and it greatly reduces the volume of sodium bentonite required.

Bentonite is a clay mineral which is largely composed of Montmorillonite, which is mainly a hydrous aluminum silicate. It is highly colloidal and plastic clay with the unique characteristic of swelling to several times its original volume when placed in water. Mining then begins by removing the overburden from the mineral deposit with the use of large earth movers. The overburden is then stockpiled nearby for reclamation after the Bentonite has been removed from the bed. When contact with the bed is made, extreme care is taken to avoid contaminating the mineral deposit with the overburden, thus insuring the highest quality raw material. Care must also be taken to conserve as much Bentonite as possible when trimming the overburden from the Bentonite. When all the Bentonite has been removed from the bed, reclamation can begin. The surface of the mine site must be returned to equal or superior condition. The habitat for plant and animal is very important as are all other environmental considerations.




This clay varies in colour from white [with reddish tinge], to green. In silu colour is darker while on exposure it fades out. When immersed in water it swells many times and forms a gel. It has a high bonding property. The specific gravity is 2.4 to 2.8 and refractive index 1.547 to 1.55, it's fusion point varies from 1330˚ C to 1430˚ C

     1. Extracted Bentonite is distinctly solid, even with a moisture content of approximately 30%.
   2. Bentonite is used as a bonding material in the preparation of molding sand for the production of iron, steel and non-ferrous casting.
   3. Used as a binding agent in the production of iron ore pellets. Through this process, iron ore fines are converted into spherical pellets, suitable as feed material in blast furnaces for pig iron production, or in the production of direct reduction iron.
   4. Acts as a good lubricating agent.
   5. Excellent absorption and adsorption properties make it an ideal option for water purification.

Bentonite is naturally occurring hydrated Aluminum Silicate. The most important use of Bentonite is based on its natural swelling property. One can surely say that Bentonite is most economic natural thickener available to industries.
It has ability to absorb water several times its weight and give thick tropic fluid. Chemically Bentonite is HYDRATED ALUMINUM SILICATE.

Recommended Uses:
The greatest application of Bentonite is in oil drilling. Great quantities of Bentonite are used in drilling mud. In paint industry it is used as a thickener in some cheap paints, primers, and water based coatings.
It is used in manufacture of cheap greases

1. Foundry Application :
    Sodium Bentonite is use in casting industries. Almost all cast iron, steel & malleable iron foundries are using this Bentonite with cost efficient results. The use of the Bentonite is successful in continuous mould making too.

2. Water well & Oil Well Drilling :
    Another conventional use of Bentonite is as a mud constituent for oil and water well drilling. Its roles are mainly to seal the borehole walls, to remove drill cuttings and to lubricate the cutting head. The Sodium based Bentonie is best for pilling work from Barmer Rajasthan.

3. Construction and Civil Engineering :
    Bentonite in civil engineering applications is used traditionally as a thixotropic, support and lubricant agent in diaphragm walls and foundations, in tunneling, in horizontal directional drilling and pipe jacking. Bentonite, due to its viscosity and plasticity, also is used in Portland cement and mortars.

Other uses

  • It is used in preparation of drilling mud for oil well drilling.

  • For a catalyst in Petroleum refining.

  • In ferrous and non ferrous metallurgy as a foundry sand bond.

  • It is also used in pharmaceuticals, cosmetics etc.

  • It is also used as a thixo-trophic agent to prevent setting of mixed paints.

  • It is used for lining canals and earthen dam in civil engineering.

  • At present sodium Bentonite is used in large quantities as a binding agent in pelletizing of iron ore fines.

  • It is also used in ceramics and insecticides.

  • Used as grouting material & in cements

  • In drilling mud

  • As a de-colorize, refining of oils & fats

  • As foundry sand

  • As binding material, pellatisation of iron ore fines In cosmetics, detergent & pharmaceutical preparations

  • As ceramics, horticultural uses

  • Animal feeding

  • Cat litter for pet

  • Agricultural applications - Fertilizers

  • Civil engineering application

Sodium bentonite is a natural sealant and is used for sealing stock and recreational ponds, dairy and sewage lagoons, and city landfills. It is also effective as a hole plug as well as for controlling dust on highways. Sodium bentonite is one of the "most effective law cost methods" of treating porous soils. It is so effective, that the Federal Government and most states require a liner of sodium bentonite or material comparable, to be used to seal toxic waste lagoons and abandoned water and oil wells. It is environmentally safe, because it contains no chemicals, no additives, nothing toxic.

There are two types of Bentonite clay:-
One is a sodium Bentonite. Sodium Bentonite has a natural swelling ability and will maintain its swelling ability throughout its use.
The other is a calcium Bentonite. Calcium Bentonite is a non-swelling bentonite. It will not swell without additives or chemicals. Calcium bentonite enhanced with additives will quickly lose its swell...It is short lived....

Bentonite is a highly versatile mineral. When processed carefully, it caters to a wide range of industries, from traditional usage areas such as metal casting, iron ore pelletizing, civil engineering, drilling, pet litter to speciality application areas such as paper, detergents, cosmetics etc.