Category Archives: Bentonite

Details of the use of bentonite

Bentonite is widely used:

1 casting industry

Casting bentonite is the largest user of bentonite, the annual amount of 1100000 tons.

Bentonite used in casting is mainly applied to the clay bonded sand, because bentonite has strong adhesion, high plasticity, good air permeability characteristics of stripping, stable physical and chemical properties, such as high temperature and wet conditions. Clay bonded sand for molding material production casting process, this is a long history, thriving in a variety of chemical bonded sand today, clay wet sand is still the most important molding material, its applicable scope, consumption of large, is any other material can not be compared to. High pressure molding, injection molding, molding, static modeling and non shock pressure vacuum process modeling in modern times, also is to use the clay wet sand as the premise, the ability to adapt to the other conditions of the clay wet sand strong. Casting bentonite mainly sodium bentonite and calcium sodium bentonite two, sodium bentonite is made from natural sodium bentonite or artificial Na bentonite processing, with its good reusability and the wet compression strength is high and the foundry industry are welcome. Because of good plasticity, can prevent the scab, scab, dropping block, sand mold collapse, and the molding cavity strong, high strength, convenient metal industry casting wet or dry mold, sand binder precision casting is preferred. Calcium sodium bentonite from natural calcium base bentonite processing, is widely used in light of casting sand binder. The utility and sand casting convenient and popular with users. Compared with other binder, bentonite has an important characteristic, is that it has certain heat capacity. As long as the heating temperature is not too high, the removal of free water bentonite as long as water, still can restore the adhesive ability. Binding capacity of bentonite in water can be manifested only after. Bentonite lose the binding ability, also with its dehydration. So far, that of bentonite in the water has three forms: a water free water, granular bentonite adsorbed water, heated to 100 ℃, can remove free water, removing free water bentonite, adhesive ability was not affected by the two kinds of water is strong; combined with water, long time heating at 110 ℃, bentonite can be removed completely free water, but does not remove firmly bound water. Has been completely removing free water bentonite, then at a higher temperature (200 ℃, 300 ℃) heating will continue to lose weight, there is still water loss. Bentonite by heating after dehydration, just add water, can completely recover bonding ability; three kinds of water is crystal water, also known as the structure of water. The lattice water to some or all removed only in high temperature. Lattice water removing swelling water, that the loss of binding capacity, become dead clay. Different bentonite, loss of binding capacity of different temperature. By differential thermal analysis experiments show that: Generally speaking, the failure temperature natural sodium bentonite is 638 ℃, calcium bentonite is 316 ℃. Artificial activation of Na bentonite, due to the activation of different conditions, the temperature is not a failure, but lower than the natural sodium bentonite.

2 drilling mud

Bentonite for drilling mud is bentonite second users, the annual amount of 700000 tons.

Bentonite is a kind of clay mineral with montmorillonite as main component, has strong water absorbability, can absorb the equivalent of 8 times the volume of the water itself, the volume expansion of 10 ~ 30 times, was suspended and colloidal state in aqueous solution. In oil, gas drilling work, want to use mud to cool the drill bit, remove debris, protect wall and equilibrium pressure. Bentonite dispersivity, grout amount is large, so it is ideal material for manufacturing drilling mud. As drilling mud bentonite, the most important requirement is the suspension properties, wet sieve analysis and moisture content.


The important effect of bentonite in drilling, makes its use very large. It is understood, the average recovery wells, about the use of bentonite 8 tons.

3 iron ore pellet

Iron ore pellet bentonite is bentonite third users, the annual amount of 450000 tons.

Iron ore pellet bentonite is one of the important material attached to the modern metallurgy industry, will concentrate powder adding bentonite bentonite and water after mixing pelletizer roll into a ball, and then drying and preheating, roasting has formed a high strength of pellet for smelting.

4 activated clay and clay particles

Activated clay is a kind of chemical products with bentonite processing, has multiple functions of activated carbon, and the price is cheaper than activated carbon. Therefore, a variety of mineral oil, the oil industry is widely applied in the petroleum industry of animal and vegetable oils, solid, liquid paraffin wax, fatty acid, regeneration of waste oil, ethanol and benzene decoloration refining. Can also be used as a Wine and juice clarification, sugar industry syrup purification, chemical industry, the catalyst powder pesticide additives etc..

Activated clay China manufacturer about 40, annual output of about 420000 tons. Device for producing ability is 50000 t/a. Activated clay production mainly concentrated in the northeast, North China, East China, production accounted for over 70% of the country. At present, the demand for activated clay in China is about 650000 t/a, annual imports of about 40000 tons.

Particulate clay is the activated clay as the main raw material, scientific formula, chemical processing and become, the appearance of unshaped granular activated clay, it has higher specific surface area and particle strength, stable performance, good selectivity, has a very high adsorption capacity, widely used in petrochemical industry aromatics purification, air kerosene refined, but also for refined oil, base oil, diesel oil, residual olefins, glial, Li Qing, and other impurities removing basic nitrogen compounds. At present, the clay particles is mainly to replace the America TONSIL particulate clay, used for the fitting of olefins removal, aviation kerosene, solvent oil refining, benzene refining, play a nitride removal, colloid, coloring effect. Particulate clay is sometimes called the oil filter oil filter using silica gel, silica gel can be good to remove the acid and the extract oil sludge, biological colloid, insulating material, can remove moisture, impurities and chromatographic analysis of hydrocarbon gases, and can be used for sewage treatment and toxic gas filtering and petrochemical industrial oil catalytic cracking.

5 desiccant

The bentonite drier with adsorption activity, static reduction effect wet and odor removal etc.. Widely used in not using oil seal, gas seal products such as: optical instruments, electronic products, medical care, food packaging and military products and civil products of dry air seal. Compared with silica gel has the advantages of low cost, fast adsorption speed, preparation and low cost. And the other type of desiccant commercially available in comparison, not only the characteristics of adsorption speed, high adsorption capacity and non-toxic, tasteless, non corrosive, non environmental pollution, especially used in food packaging, no harm to human body.

The bentonite drier larger export volume.

6 litter (granular bentonite)

Litter (granular bentonite) uses the high quality natural bentonite, after high temperature drying refined, has a white color appearance, strong adsorption characteristics, the proportion of small, durable, suitable for family pets sanitation purposes.

Litter (granular bentonite) exports large.

7 sewage treatment

Bentonite used as animal feed processing wastewater, gasket odor bentonite can make animal feces easily dispersed, cleaning. The captive animal farms and slaughterhouses, aquatic products processing field generated sewage, odor and harmful to the environment, and bentonite in these places, the recovery efficiency of fertilizer.

Bentonite can be used as clarifier in muddy water, polluted water proofing agent, sewage treatment agent. Printing and dyeing wastewater with bentonite, coal gas washing wastewater, monosodium glutamate factory waste water, waste, removal rate of 99.5%.

And bentonite in the upstream of the reservoir the reservoir unclean substances into the bottom of the flocculation biological purification treatment.

8,The  Construction Engineering

The lubrication of bentonite, bonding and sealing, thickening and gelling into mud, used for lining wall impermeable soil operations, such as wall construction, grouting, pile, caisson, land impervious, cement and concrete construction additives, solid water transport, sewage treatment and tunnel shield lubrication.

Bentonite impervious layer Pu River, the limited water leads to distant. Bentonite waterproof layer can be made of natural sodium bentonite powder is spread directly, also can use bentonite with local soil compaction, can also be bentonite sandwiched between two layers of fabric to form a waterproof (permeability) blanket (plate), fast to build a reservoir, reservoir water kiln, the canal.

Bentonite can be used as waterproof materials, waterproof felt waterproof board, corrugated cardboard loaded bentonite sandwiched between two layers of non-woven fabrics of bentonite and a layer of non-woven fabric with a plastic board is clamped in the middle of the bentonite double waterproof board, this material has been widely used in the subway, the bottom of the dam, the landfill of underground engineering in the process of. Bentonite has high water tightness and self repair function of the restoration, waterproof have compactness (sodium bentonite in water to form the diaphragm, the compactness of the 30cm thickness of clay layer thickness is about 5mm, equivalent to 100 times of water), self performance (sodium bentonite and water reaction when, with expansion force, L3l6 times so it can repair 2mm within the cracks of concrete surface with waterproof performance) and permanent (sodium bentonite does not occur with aging or corrosion) etc.. Harmless to human body of bentonite, environmental performance is excellent. Simple construction. No need for heating and paste, not affected by temperature. At the same time, short construction period, compared with other waterproof materials, construction is relatively simple compared to soft. Only the nails and washer. After the construction does not need the special inspection, if found waterproof defects also easy to repair.

9 food

As food additives and emulsifier in food, can be used as calcium and diet food.

Bentonite can make juice, juice clarification.

Bentonite can soften hard water.

Bentonite to fix nitrogen deposition method for wine clarification, reduce acetaldehyde formation and the formation of hydrogen sulfide, eliminate all alien smell.

10 coating

Bentonite in papermaking industry as multifunctional white paint, anti pitching adsorption agent, maintaining agent, in the pulp of rheological modifier role in machinery it still pulper.

Bentonite can also produce coating. As the viscosity regulator and white mineral filler in the coating, which can partially or completely replace titanium dioxide; also can replace part of polyvinyl alcohol, as well as binder for nonwoven, gypsum particles.

Bentonite of oxidized starch adhesive was modified, which can not only improve the solid content, gum reduced the water, also can plug and fill the paper fiber (especially the straw pulp paper) space, reduce the moisture permeability, thus improves the initial adhesion adhesive and drying speed. Experiments prove that the bentonite effect is good, and the price is low, is the ideal drying agent.

Bentonite Overview and Classification

The bentonite interlayer cations depends on the type of bentonite type, interlayer cation is Na+ called sodium bentonite; interlayer cation is Ca2+ called calcium base bentonite; interlayer cation is H+ called hydrogen bentonite (activated clay, natural bleaching soil acid clay); interlayer cation organic cation organic bentonite.

Classification of bentonite:

Activated clay:

Activated clay is a clay (mainly bentonite) as raw material, the inorganic acid, followed by water rinsing, drying adsorbent made of, look for the milky white powder, odorless, tasteless, non-toxic, strong adsorption, can adsorb colored material, organic matter. Easy to absorb moisture in the air, place too long will reduce the adsorption properties. However, heated to 300 degrees Celsius above began to lose water of crystallization, the structure changes, effects of fading effect. Activated clay is insoluble in water, organic solvents and oils, almost completely soluble in hot caustic soda and hydrochloric acid, the relative density of 2.3 ~ 2.5, in water and oil swelling minima.


Natural bleaching clay:

The natural output itself has a bleaching properties of clay, montmorillonite, with sodium feldspar, quartz is the main component of the white, white and gray clay, is a kind of bentonite.

Is mainly a result of vitreous volcano rock after the decomposition of water after the expansion, it is not, the pH value of the suspension is weak acidic and alkaline bentonite phase difference; the bleaching performance than activated clay difference. Color generally have pale yellow, green and white, grey, Xi Lan color, brown, white, pink, blue. Very few pure white. The density of 2.7-2.9g/cm. Apparent density because of the porous nature relationship and often lower. The chemical composition and the ordinary clay almost, is the main chemical compositions of three two aluminum oxide, silica, water and a small amount of iron, magnesium, calcium. No plasticity, have higher adsorption. Because of containing a large amount of acidic aqueous silicate, litmus. Water easily cracking, high water content. General rules for higher fineness the decoloring capacity.

Quality evaluation is at the exploration stage, to determine the bleaching properties, acidity, filtration, oil absorption etc.


Organic bentonite is a kind of inorganic / organic ammonium compound, using bentonite as raw material, the lamellar structure of montmorillonite in bentonite and its energy in water or organic solvent swelling dispersing into colloid clay characteristics, by ion exchange technology insertion organic covering agent and made of. Organic bentonite can form gel in all kinds of organic solvent, oil, liquid resin, has good thickening, thixotropy, suspension stability, high temperature stability, lubricity, film, water resistance and chemical stability, and has important application value in the coatings industry. They are widely used in paint and ink, aviation, metallurgy, chemical, petroleum industry etc..

Soil mineral:

Bentonite ore is a multi-purpose mineral, its quality and application fields mainly depends on the content of montmorillonite and attribute types and their crystal chemistry characteristics. Thus, its development and utilization must be different according to the different mine, because of different. Such as the production of activated clay, sodium calcium base to base, drilling grouting for oil drilling, instead of starch pastes for spinning, dyeing and printing, building materials for interior and exterior wall paint, preparation of organic bentonite, bentonite, zeolite 4A synthesis in white carbon black production etc..

Calcium and sodium based difference:

The bentonite interlayer cations depends on the type of bentonite type, interlayer cation is Na+ called sodium bentonite; interlayer cation is Ca+ called calcium base bentonite. Sodium montmorillonite (or sodium bentonite) properties than calcium. But the distribution of the calcareous soil far wider than sodic soil, so in addition to find sodic soil is to calcareous soil was modified, make it become sodic soil.

Bentonite encyclopedic knowledge

Bentonite (Bentonite) is an aqueous clay mineral montmorillonite based. The chemical composition of montmorillonite as: (Al2, Mg3) Si4O10 OH2 · nH2O, because of its special properties. Such as swelling, adhesion, adsorption, catalysis, thixotropy, suspension and cation exchange. It is widely used in various industrial fields.

Bentonite is non-metallic mineral montmorillonite as the main mineral composition, the structure of montmorillonite is 2:1 type crystal structure consists of two silicon oxygen tetrahedron sandwiching a layer of alumina in eight face bentonite composition, due to the layered structure of montmorillonite crystal formation in the presence of some cations, such as Cu, Mg, Na, K, and these cationic and montmorillonite lattice effect is very unstable, easily by other cation exchange, it has good ion exchange. Abroad has been in the industry and agriculture production more than 100 departments in 24 fields of application, there are more than 300 products, so people called the “universal soil”.

Bentonite is also called bentonite, bentonite and bentonite. History of China’s development of the use of bentonite is long, just as a detergent. (Sichuan Renshou area hundreds of years ago in open-pit mine, the locals of bentonite clay powder). Really is widely used but only a hundred years of history. USA was first discovered in the ancient stratigraphic Wyoming, green yellow clay, the water after the expansion into paste, then people will take all the properties of bentonite clay, collectively referred to as. In fact, the main mineral component of bentonite is montmorillonite, content of 85-90%, some properties of bentonite are also determined by the montmorillonite. Montmorillonite can be a variety of colors such as yellow green, Huang Bai, gray, white and so on. Can a dense block, but also loose earth sometimes, when you rub it with your fingers with smooth feel, small body after adding water volume swell several times to 20-30 times, is suspended in the water, when water is little mushy. The properties of montmorillonite and the chemical composition and its internal structure.


The bentonite interlayer cations depends on the type of bentonite type, interlayer cation is Na+ called sodium bentonite; interlayer cation is Ca2+ called calcium base bentonite; interlayer cation is H+ called hydrogen bentonite (activated clay, natural bleaching soil acid clay); interlayer cation organic cation organic bentonite.

Bentonite is a kind of clay, montmorillonite clay rock or rock, often containing a small amount of illite, kaolinite, halloysite, chlorite, quartz, feldspar, zeolite, calcite; usually white, pale yellow, due to changes in iron content is light gray, light green, pink, brown red, brick red, black etc.; with wax, earthy or oil sheen; bentonite some loose soil, there are dense and hard. The main chemical composition is three silica, two aluminum oxide and water, also contain iron, magnesium, calcium, sodium, potassium and other elements, Na2O and CaO content on properties of physical and chemical properties of bentonite and technology influence. Montmorillonite belongs to monoclinic system, usually it is earthy block, white, sometimes reddish, greenish, yellowish color. Luster dim. Hardness of 1 ~ 2, density of 2 ~ 3g/cm3. Type, content and layer charge of montmorillonite according to the size of the exchangeable cation, bentonite can be divided into Na bentonite (alkaline soil), calcium base bentonite (alkaline soil), natural bleaching earth (acidic soil or clay acid), in which calcium bentonite and sodium calcium base and calcium and magnesium based etc.. Bentonite has strong hygroscopic and expansion, water adsorption can be 8 to 15 times their size, the volume expansion of up to two to 30 times; can be dispersed into gelatinous and suspended in water medium, the medium solution with viscosity, degeneration and some lubrication; strong cation exchange capacity; for various gases, liquids, organic matter has certain adsorption capacity, the maximum adsorption capacity of up to 5 times its own weight; it with water, mud or sand blends with plasticity and cohesiveness; acid bleaching soil with surface activity (active white soil, natural bleaching soil acidity clay can adsorb colored ion).

Bentonite has strong moisture absorption, can absorb the equivalent volume 8 20 times of water and swells to 30 times; can be dispersed colloidal suspensions in water medium, and has a certain viscosity, thixotropy and lubrication, the admixture of bentonite and silt has plasticity and cohesiveness, strong cation exchange capacity and adsorption capacity.

The naked eye identification, high-quality bentonite was pure white, generally have gray or no yellow white, often due to water or containing impurities are pale green, pale green, rose red color. After drying is pure white, gray or pale yellow white. In section is not smooth hand after the break, but a jelly. There are oil sheen, hand touch with smooth feel. Can water swelling, good can become colloid. If long-term dry moisture loss, and can become loose. Bentonite has strong ion exchange capacity, so it can be adsorbed or absorbed a variety of colors. It can make the oil and oil mixed, more smooth. Suspension of fine powder of its water, dispersion (divergence) is very good, not easy to precipitate. The natural bentonite type, mainly by the relative content of montmorillonite cation species divided into calcium, sodium, hydrogen, Lithium Montmorillonite, such as the calcium montmorillonite based clay called calcium base bentonite. Most of bentonite ore in China in the production of calcium base bentonite, calcium base bentonite sodium bentonite is cheap, and easily, so we in the broiler and layer test, are calcium base bentonite. With the addition of bentonite feeding chickens, because good palatability, chicken to eat.

But only by the naked eye, sensory evaluation is not accurate. There is no uniform identification of bentonite in China National standard. The majority of mine to execute a machine on the “casting bentonite, a clay ministerial standard” (1997) and enterprise standards. The main absorption of blue, water, colloid medium, pass rate, wet strength, expansion coefficient, pH value, determination methods and standards here omitted.

The county more than bentonite plant has more than 20, and do the bentonite plant has more than 100, the vast majority of provinces (autonomous regions) are. Most of the county (city) building materials company or goods shopping malls have bentonite. Market town where the foundry factory usually with bentonite, less dosage can contact them, but must pay attention to quality.