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Péngrùntǔ jiàndìng 5/5000 Bentonite identification

Release date:2018-12-21  source:中南选矿网  Browse times:732
Core Tip: Bentonite is a hydrated clay mineral dominated by montmorillonite. The chemical composition of montmorillonite is: (Al2, Mg3)Si4O10 OH2nH2O, due to its special

 

Drilling fluid grade bentonite Bentonite is a hydrated clay mineral dominated by montmorillonite. The chemical composition of montmorillonite is: (Al2, Mg3) Si4O10 OH2•nH2O due to its special properties. Such as swellability, cohesiveness, adsorption, catalytic, thixotropic, suspension and cation exchangeability. Therefore, it is widely used in various industrial fields. Bentonite is a non-metallic mineral with montmorillonite as the main mineral component. The montmorillonite structure is composed of two silicon oxide tetrahedrons with a layer of aluminum oxide octahedron.


Bentonite

The 2:1 type crystal structure [1], due to the existence of certain cations in the layered structure formed by the smectite unit cell, such as Cu, Mg, Na, K, etc., and the role of these cations with the montmorillonite unit cell is very It is not strong and is easily exchanged by other cations, so it has good ion exchange property. Foreign countries have been applied in more than 100 departments in the 24 fields of industrial and agricultural production, and there are more than 300 products, so people call it “universal soil”. Bentonite is also called porphyry, bentonite or bentonite. China has a long history of developing bentonite, which was originally used as a detergent. (Sichuan’s Renshou area has open pit mines hundreds of years ago, and locals call bentonite a soil powder). It is really widely used but only a hundred years old. The earliest discovery in the United States was in the ancient strata of Wyoming, which was yellow-green clay. After adding water, it expanded into a paste. Later, people called clays of this nature collectively called bentonite. In fact, the main mineral component of bentonite is montmorillonite, the content is 85-90%, and some properties of bentonite are also determined by montmorillonite. Montmorillonite can be in various colors such as yellow-green, yellow-white, gray, white, and the like. It can be made into a dense block or a loose soil. It has a slippery feel when rubbed with a finger. The volume of the small block is several times to 20-30 times when it is added with water. It is suspended in water and is mushy when there is little water. . The nature of montmorillonite is related to its chemical composition and internal structure. [Property and application] The nature of montmorillonite and the type of exchangeable cations between layers have a great relationship. According to the type of the main exchangeable cation between the layers, montmorillonite is usually classified into calcium montmorillonite and sodium montmorillonite. Montmorillonite has adsorptive and cation exchange properties, can be used to remove oil toxins, gasoline and kerosene purification, wastewater treatment; due to good water swelling properties and dispersion and suspension and pulpability, it is used in drilling mud, Flame retardant (suspended fire extinguishing); can also be used as filler in the paper industry to optimize coating properties such as adhesion, hiding power, water resistance, scrub resistance, etc.; because of good adhesion, it can be used instead of starch. The yarn sizing in the textile industry is both grain-saving and hairless, and it does not emit odor after the paddle. In general, sodium montmorillonite (or sodium bentonite) is better than calcium. However, the distribution of calcareous soil in the world is much wider than that of sodium soil. Therefore, in addition to strengthening the search for sodium soil, it is necessary to modify the calcareous soil to make it a sodium soil. Bentonite (montmorillonite) can be used as a binder, suspending agent, thixotropic agent, stabilizer, purification decolorizer, filler, feed, catalyst, etc. due to its good physical and chemical properties. It is widely used in agriculture, light industry and cosmetics. In the field of medicines, etc., montmorillonite is a natural mineral material with a wide range of uses.

【composition】

In 1898, American geological scholar Knighl discovered a green-yellow water-swelling clay material near the Rocky Mountain River in Wyoming, USA. Because of its origin: "Fort Beton", it was named Bentonite. Bentonite is also called porphyrite or bentonite. The main mineral component of bentonite is montmorillonite, the content is 85-90%. Some properties of bentonite are also determined by montmorillonite. Montmorillonite can be in various colors such as yellow-green, yellow-white, gray, white, and the like. It can be made into a dense block or a loose soil. It has a slippery feel when honed with a finger. The small body is bulky when it is added with water. It is suspended in water and has a paste when there is little water. Montmorillonite has adsorptive and cation exchange properties, can be used to remove petroleum toxins, gasoline and kerosene purification, wastewater treatment; due to good water swelling properties and dispersion and suspension and pulpability, it is used in drilling mud, Flame retardant (suspended fire extinguishing); can also be used as filler in the paper industry to optimize coating properties such as adhesion, hiding power, water resistance, scrub resistance, etc.; because of good adhesion, it can be used instead of starch. The yarn sizing in the textile industry is both grain-saving and lint-free, and does not emit odor after the pulp.

Classification of bentonite

The type of interlayer cation of bentonite determines the type of bentonite. When the interlayer cation is Na+, it is called sodium bentonite; when the interlayer cation is Ca+, it is called calcium bentonite; when the interlayer cation is H+, it is called hydrogen bentonite (active clay); When the cation is an organic cation, it is called organic bentonite.

The nature of bentonite

Bentonite has strong hygroscopicity, can absorb water equivalent to 8-20 times its own volume and expands to 30 times; it can disperse in colloidal suspension in aqueous medium, and has certain viscosity, thixotropy and lubricity. It has a plasticity and cohesiveness with a blend of sediment and the like, and has a strong cation exchange capacity and adsorption capacity.

[Edit this paragraph] Application of bentonite

Bentonite is known as “universal” clay because of its good physical and chemical properties. It can be used as a binder, suspending agent, thixotropic agent, stabilizer, purification decolorizer, filler, feed, catalyst, etc. , petroleum, foundry, food, chemical, environmental and other industrial sectors.

[The development status of bentonite in China]

China's bentonite reserves are second only to the United States, ranking second in the world. The current mining volume is 2 million tons, mainly concentrated in the northeast and eastern coastal provinces. More than 400 large and small deposits and mines have been discovered in China, with proven reserves of 2.33 billion tons and estimated resources of more than 7.5 billion tons. However, the degree of development and utilization of bentonite is very low, and the cumulative production is less than 1% of the proven reserves. In the international market, it is a situation of “lower and higher”, that is, exporting low-grade products (original ore, foundry, drilling, low-grade activated clay, etc.), imported advanced products (washing powder softener, high-grade organic soil, bentonite waterproof) Blankets, etc.). According to incomplete statistics, China's current bentonite products have an annual production and sales volume of about 2.7 million tons, including 100-1.1 million tons for foundry sand, 70 tons for drilling mud, and 450,000 tons for metallurgical pellets. White clay) 200,000 tons, used for other 200,000 to 300,000 tons. The industry is characterized by a small scale of enterprises (a small number of enterprises with an annual output of over 10,000 tons) and a low level of technology. As it is a resource-based industry, competition is not very intense, and production, sales and prices are rising year by year.

 
 
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