Bentonite is perhaps the most widely used type of natural clay in our country and in the world. The main mineral that makes up this material is montmorillonite, which has unique hydrophilic properties. Actually bentonite clay can be called only if this highly dispersive aluminosilicate will contain at least 70% of its composition.
How the deposits were formed
Bentonite clay is mined in open pit mines. This material was formed a very long time ago - about 25 million years ago at the bottom of the prehistoric ocean from volcanic ash and tuff. For the first time bentonite clay was discovered in the USA in 1898 near the town of Benton. Hence its name.
The high content of montmorillonite and gives unique properties to bentonite. First, due to non-stoichiometric substitutions of cations, the particles of this mineral have an excessive negative charge. Secondly, the crystal lattice of montmorillonite has 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 such minerals as knees, feldspars, quartz, hydromica, sepiolites, etc.
The scope of application of bentonite clay is very wide. They are used in almost all areas of the national economy. In the food industry they are used to clarify wines and juices. Since such clays contain almost all micro- and macronutrients useful for living organisms, they are often added to animal feed. Bentonites are also used in the process of cleansing the land from various kinds of chemical pollution.
The most widely used clay is found:
In the oil industry. Bentonite powder is added to water when flushing oil wells. The thin film created by him prevents the penetration of oil into the mine, which excludes spouting. Bentonite clay is also used for flushing while drilling wells for water.
In cosmetology. This material is often added to creams and shampoos. Being applied to the skin or added to bathing water, negatively charged bentonite clay pulls positively charged particles of dirt and bacteria from the pores.
In the metallurgical industry. Concrete is part of the molding compounds, and is also used in the process of manufacturing iron ore pellets.
In construction. When mixing this type of clay in a limited space, it is transformed into a special gel that does not let the water through at all. The latter is often used in the manufacture of waterproofing materials. Also, bentonite clay is used for the manufacture of tiles, designed for interior decoration, both inside and outside.
In light industry. Economic and artistic porcelain, as well as radio and electroceramics are made of bentonite clay.
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 capable of removing toxins from the body of various kinds and having a beneficial effect on the gastrointestinal tract. Also, this material is usually included in the ointment mummy.
Advantages and disadvantages
The widespread use of bentonite clay in the national economy due to the many inherent advantages of this material. Its advantages can be attributed primarily to:
excellent waterproofing properties;
the ability to withstand without harm for yourself a huge number of cycles of freezing and thawing;
relatively low cost.
This material has practically no disadvantages. Sometimes there are deposits of too oily bentonite clay. Products made of it may crack when dry. However, this disadvantage is easily eliminated through special treatments.
This material is thus used very widely. Accordingly, it can be marked in different ways. For example, in the oil industry mainly bentonite PBMG clay is used. This material quickly shuts, has a low rate of filtration and resistance to polyvalent aggression. To improve the characteristics of the clay of this brand is modified using a calcined salt.
Also, when drilling wells, PBG and PPD powders are often used. They are slightly more dense than PBMG bentonite clay.
The material used in the manufacture of ceramic tiles is marked with the letters SC. Its chemical composition is governed by GOST. Clay intended for the manufacture of ceramic tableware, labeled PRK.
In the metallurgical industry, bentonite clay of different composition can be used. The first letter in its labeling indicates the degree of strength, the next figure characterizes the bonding qualities, and the index of the latter - thermal stability.
Where is mined
Bentonite clay deposits are being developed in many countries of the world: Italy, USA, Greece, Japan, etc. Russia is the largest supplier of this material. A huge amount of this material is mined in such fields as the “10th farm” in Khakassia, “Zyryanskoe” in the Kurgan region, “Lyublinskoye” in Western Siberia and many others.