Bentonite is perhaps the most widely used type of natural clay in our country and in the world. The main mineral that is part of this material is the unique hydrophilic properties of montmorillonite. Bentonite clay itself can be called only if this highly dispersive aluminosilicate in its composition will include at least 70%.
How the deposits formed
Bentonite clay is extracted by open-pit mining in quarries. This material was formed very long ago - about 25 million years ago at the bottom of the prehistoric ocean from volcanic ash and tuff. Bentonite clay was first discovered in the USA in 1898 near the town of Benton. Hence its name.
High content of montmorillonite and gives unique properties to bentonite. First, the particles of this mineral, due to nonstoichiometric substitutions of cations, have an excess negative charge. Secondly, the crystal lattice of montmorillonite differs in a layered structure. These factors determine the high hydrophilic properties of bentonites. Clays of this variety are able to absorb a huge amount of water, while significantly increasing in volume. In addition to montmorillonite, bentonite includes minerals such as kolenite, feldspar, quartz, hydromica, sepiolite, etc.
Where to use
The scope of bentonite clays is very wide. They are used practically in all areas of the national economy. In the food industry, they are used for clarifying wines and juices. Since such clays contain almost all micro-and macro-elements useful for living organisms, they are often added to the feed of agricultural animals. Bentonites are also used in the process of cleansing the land of various kinds of chemical pollution.
The most widespread use of these clays found:
In the oil industry. Bentonite powder is added to water when washing oil wells. The thin film created by it prevents the penetration of oil into the mine, which excludes the flowing. Bentonite clay is used and for washing when drilling wells for water.
In cosmetology. This material is often added to creams and shampoos. When applied to the skin or added to the water during bathing, the negatively charged bentonite clay draws positively charged particles of dirt and bacteria from the pores.
In the metallurgical industry. Concrete is a part of molding mixtures, and is also used in the process of making iron ore pellets.
In construction. When kneading clay of this type in conditions of limited space, it is transformed into a special gel that completely does not allow water to pass through. The latter is often used in the manufacture of waterproofing materials. Bentonite clay is also used for making tiles intended for interior decoration both inside and outside.
In light industry. Bentonite clay produces economic and artistic porcelain, as well as radio and electroceramics.
In the chemical industry. Because this material contains a lot of sodium, it is often used to make household cleaners.
In medicine. Bentonite clay is also used as a means to remove from the body all sorts of toxins and has a beneficial effect on the work of the digestive tract. Also this material is usually included in the ointment mummies.
Advantages and disadvantages
The wide use of bentonite clays in the national economy is due to the many inherent advantages of this material. To its advantages can be attributed in the first place:
excellent waterproofing properties;
ability to withstand without harm to yourself a huge number of cycles of freezing and thawing;
relatively low cost.
There are practically no shortcomings in this material. Sometimes there are deposits of oily bentonite clay. The products made from it can dry during drying. However, this deficiency is easily eliminated by special treatments.
This material is used, therefore, very widely. Accordingly, it can be marked differently. For example, the oil industry uses mainly clay bentonite PBMG. This material quickly closes, has a low filtration index and resistance to polyvalent aggression. To improve the characteristics of clay this brand is modified using calcined salt.
Also, when drilling wells, PBG and PPD powders are often used. They are slightly more dense than the bentonite grade PBMG.
The material used in the manufacture of ceramic tiles is marked with letters SK. Its chemical composition is regulated by GOST. Clay, intended for the manufacture of ceramic dishes, is labeled by PRK.
In the metallurgical industry, a different bentonite clay can be used. The first letter in its marking indicates the degree of strength, the next figure characterizes the binding qualities, and the index of the latter - thermal stability.
Where do they extract
Deposits of bentonite clays are being developed in many countries of the world: Italy, the USA, Greece, Japan, etc. Russia is also the largest supplier of this material. A huge amount of this material is mined in such deposits as the "10th farm" in Khakassia, "Zyryansky" in the Kurgan region, "Lublin" in Western Siberia and many others.