Applications of Bentonite: 

Molding Sand 

Bentonite is still used in the manufacture of molds for casting, even though the industry has begun using other technologies and has been replacing the Bentonite by other products.   The process known as smelting is one in which a molten metal is poured into a mold having the shape of the article to be produced, which is obtained after the metal cools and solidifies.   Molding sands are composed of sand and clay, usually Bentonite, which provides cohesion and plasticity to the mix. This makes it easier to mold once the molten material has been poured and gives sufficient strength to retain the shape when the mold is being removed.   The proportion of Bentonite in the mixture varies between 5 and 10%; it can contain as much sodium as calcium, depending on its intended use as a mold. Sodium Bentonite is used instead of the calcium variety in foundries for higher temperatures. Sodium Bentonite is typically used for cast iron, malleable and ductile iron, and less so for the range of non-ferrous metals. On the other hand, calcium Bentonite facilitates the production of complex molds with more detail and is used mainly in non-ferrous metal smelting.   The specifications developed by industry associations for foundry Bentonites include properties such as moisture content, expansion index, pH values and liquid limits, among others. 

Drilling Mud 

Despite the many changes that have taken place in the formulations of drilling mud, Bentonite is still used in many ways.   Drilling mud is pumped and circulated through a well while it is being drilled. Its composition is adjusted as requirements change, according to the depth of drilling and the presence of other found materials.   
The functions performed by drilling mud are:    
- Control pressure during the formation and stabilization of the walls 
- Cool the drilling tool 
- Seal or form a thin impermeable coating on the wall of the well that prevents water from affecting the geological formation. 
- Enable the addition of weighting agents 
- Produce hydrostatic pressure sufficient to stabilize the wall and trap the geological formation fluids. 
- Remove debris from the bottom of the pit and transport it to the surface. 
- Support the weight of the drill 
- Transmit hydraulic power to the drill   A wide variety of industrial minerals and chemicals are used in drilling mud, but the most important ingredient is always Bentonite. Its use is based on increasing the viscosity of the mud, which ensures the effective removal of surface debris. 


Pelletizing 

For over fifty years Bentonite has been used as a binder in the production of pellets of material previously pulverized during separation and concentration tasks.   Although there are no standard specifications for this use, natural or activated sodium Bentonites are used since they are the only ones that form good pellets with the green and dry strength required, as well as the high mechanical strength required after calcification. 


Absorbents 

The high specific surface of Bentonite gives it a large capacity for both absorption and adsorption. Therefore, it is used in the bleaching and clarification of oils, wines, ciders, beers, etc. Bentonites are importance in industrial processes for purifying water that contains different types of industrial oils and organic contaminants.   Bentonites are also used as a carrier for chemicals such as herbicides, pesticides and insecticides, allowing a homogeneous distribution of toxic products.       

Sealing Material 

Bentonites can be used as a sealing material for deposits of both toxic and dangerous waste, as well as for those with low, medium and high radioactive activity. Bentonites are used in soil mixes to reduce permeability and prevent the escape of gas or leachate generated in the tank.   The normal process is to mix the sand with Bentonite, although recently there has been a growing trend in the design of barriers in the use of waterproofing geomembranes and geotextiles. The seals are formed by a compacted clay barrier between geotextile and geomembrane layers.   The geomembrane is waterproof, while the geotextile is permeable, so this allows the Bentonite to expand and produce the compacted sealing barrier.   The usefulness of Bentonite as sealing material is mainly based on some of its characteristic properties, such as high specific surface, high expansion capacity, good plasticity and lubricity, high impermeability, and low compressibility. Bentonites commonly used for this purpose are the sodium type, which have a greater capacity for expansion. 

Physical Land 

In rocky or volcanic areas where it is difficult to obtain satisfactory values of resistance, it is common to use Bentonite as an addition to the soil on which something is placed in order to improve its stability. 

Manufacture of Soap 

Bentonite is a very interesting component of soap because of its emulsifying properties and the detergent effect of its carbonaceous particles. Among its properties and great power advantages are: its emulsifying and detergent action due to the viscous suspension of the gel it contains; its ability to disperse in water more quickly than other soaps because of its colloidal clay content; its base-changing property that softens hard water and reduces the excess alkali in soap, creating a self-protective effect on human tissues; likewise, its emulsifying properties and more rapid and complete saponification of fats; its advantage of drying and aging much less than other soaps; and, its good stability quickly obtains water balance as well as a low sensitivity to deformation and softening in hot water. 

Civil Engineering

Bentonites are used to cement cracks and crevices in rocks; absorb moisture to prevent the collapse of tunnels and excavations; waterproof trenches; stabilize ponds; etc.    
Primary uses include:    
- Increase the capacity and plasticity of cement to be worked 
- Stabilize and support the construction of tunnels 
- Lubricate and fill cracks in pipes 
- Support excavations 
- Create a waterproof membrane barrier on the floor 
- In public works, prevent the collapse of walls by lubricating with Bentonite grout 
- Provide security in the event of breakage of wires buried underground   In excavations, Bentonite clays are used to provide non-mechanical wall brackets. Bentonite mud can also be used as a lubricant for the expansion of the mold and drilling of piles and similar foundations. It is also used in a wide variety of building materials including bricks, Portland cement, gypsum products, drainage pipes and tiles. 


Animal Feed 

Bentonite has applications in the preparation of animal feed concentrates as an adsorbent of toxins, as a binder in pelletizing processes or formation of granules, and as a nutritional additive.   Its application as a binder in the manufacture of pelleted food for animals is widely used in feed for chickens, pigs, turkeys, goats, sheep, and cattle. Bentonite acts not only as a binder but also serves as a carrier for vitamins, minerals, antibiotics and other additives.   Recently its incorporation into poultry feed has yielded substantial benefits such as increased egg production, and size and hardness of the egg shell.   Bentonite has a dual mission: it acts as a growth promoter and as a scavenger for toxins. This is because food mixed with Bentonite, due to its high adsorption capacity, remains longer in the intestinal tract, where the clay adsorbs the excess water and makes the nutrients remain in the stomach longer. On the other hand, it absorbs toxins and prevents them from passing through the intestinal walls. Further, by increasing the absorption of nutrients Bentonite makes the stool less humid, so the bed remains clean longer and the likelihood of epidemics and the proliferation of flies and parasites are reduced.   Bentonite is a natural absorbent agent of toxins, especially aflatoxins. By spraying it on cereal grains, oilseeds and products, it prevents the proliferation of fungi caused by moisture and temperature. It eliminates toxins and is used for its high astringent power, its great capacity for adhesion and its fungicidal capacity.   When in contact with water and digestive juices, Bentonite exerts a detoxification action in the animal's intestinal tract, forming a stable and insoluble complex between the mycotoxins and the Bentonite preventing their being assimilated and ensuring that they are eliminated with the feces.   As binder, Bentonite does not transmit any taste or smell to food. It offers excellent performance in the manufacture of pellets or granules, acting as a lubricant and increasing the hardness.   As a nutritional additive, it promotes interaction with proteins, peptides and amino acids through their weak links, improving zootechnical performance. Bentonite also acts as a vehicle for providing vitamins, minerals, antibiotics and other supplements. 

Catalysts 

There are many applications of clays as catalysts in various chemical processes. For example, they are used in gasoline desulfurization reactions, isomerization of terpenes, polymerization of olefins, cracking of petroleum, and so on.   The catalytic properties of Bentonites are a direct result of their high specific surface area and localization of acid center (i.e., acid activation).   For this reason, the search for maximizing the surface area is a regular line of research and application of clays. 

Pharmaceutical Industry 

Bentonites long have been used as an excipient for the pharmaceutical industry because they are not toxic or irritating. They also have been used for the development of both topical and oral preparations because they cannot be absorbed by the human body. Bentonite is used as adsorbent, stabilizer, thickener, suspending agent and as a viscosity modifier.   Their main use is in the preparation of topical suspensions, gels and solutions. 

Clarification of Wines and Juices 

Artificial or induced clarification, as opposed to spontaneous clarification that occurs naturally in wine, is aimed at obtaining the clarity of the wine in a more or less shorter amount of time.   Artificial clarification consists of adding certain substances in the colloidal state which, in order to coagulate and flocculate, seep through by physical and chemical action to colloid wine compounds. The substances used to clarify wines are called clarifiers.   Bentonite is the most widely used clarifier, because it has a low cost, is totally inert and inalterable, is easy to use and has a remarkable stabilizing effect on wine.   The same criteria are applicable for general clarification of juices, and certain fruits in particular.