The main mineral component of bentonite is montmorillonite, with a content of 85-90%. Some properties of bentonite are also determined by montmorillonite.  

The structure of montmorillonite is a 2:1 type crystal structure composed of two silicon-oxygen tetrahedrons and a layer of aluminum-oxygen octahedron. There are some cations in the layered structure formed by the unit cell of montmorillonite. When the interlayer cation is Na+, it is called soudium bentonite; when the interlayer cation is Ca2+, it is called calcium bentonite; when the interlayer cation is an organic cation, it is called organic bentonite. 

 

Sodium bentonite has a better adsorption and swelling property than calcium bentonite. 

Application: 

Paints&Coatings Industry:

1: Bentonite forms a flocculent substance in water which has a thickening effect. Its molecular group can be combined with the organic binder in the paints&coatings, which can enhance the water resistance of the paints&coatings and improve the strength and adhesion of the paints&coatings. 

2: Bentonite makes the paints&coatings not easy to settle, stratify, makes the color of paints more uniform, thereby improving the stability of the coating suspension and brushing performance. And it can form a uniform thickness, flat and smooth coating layer. 

3: Bentonite could replace titanium dioxide in paints&coatings. 

Adhesive Usage:

1: Bentonite could be used in adhesive for non-woven fabrics and plaster granules. 

2: A certain heat-resistance performance. 

Casting Industry:

Because of good of plasticity of bentonite, it can prevent sand inclusion, scarring, lumps, sand collapse and other phenomena in castings. In addition, it has strong molding performance and high cavity strength, which is convenient for casting wet or dry molds in the metal industry. It is a prefered sanding agent in precision casting. 

Usually sodium bentonite is mostly used in casting industry.

Drilling Mud: 

When performing oil and gas drilling, mud is used to cool the drill bit, eliminaate debris, protect the well wall and balance the ground pressure. Bentonite has strong water absorption, can absorb 8 times the volume of its own, and expand 10-30 times in volume. It is suspended and gelled in the aqueous solution. It has good dispersibility and large slurry output. Therefore, it is used for manufacturing drilling well. Ideal material for drilling mud. 

Bentonite is also used in such industries such as iron ore pellts, cat litter and water-proof materials.