Uses and Applications of Bentonites - 2

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.

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.

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.

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.

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.

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.