What is tracing paper and talc. Properties and uses of talc. Historical information about talc

Talc is a mineral from the class of hydrous aluminosilicates, the talc group. Chemical formula: Mg 3 (0H) 2 .

The shine is greasy, pearlescent. Hardness 1. Specific gravity 2.7-2.8 g/cm3. Greasy to the touch. Color: light green, greenish-white, greenish-gray, yellowish-gray, yellowish-white, white. The line is white. The crystal structure of talc is close to the crystal structure of mica. In the crystal lattice of talc, between layers consisting of hexagonal networks formed by silicon and oxygen, there are magnesium cations. The cleavage of talc is very perfect. Leafy, scaly aggregates are characteristic. The leaves are flexible, but not elastic.

Features . Talc is characterized by a non-metallic luster, slight hardness, light green, greenish-white, greenish-gray, yellowish-gray, yellowish-white, white, white line; It is especially characteristic that talc feels greasy to the touch. Similar to white mica (). Unlike talc, muscovite leaves are elastic and flexible.

Types and photos of talc

Minnesotaite(Fe content 50-80 at.%);
Willemseit- essentially nickel-plated;
Steatite(wen) - dense, massive;
Agalite- fine-fiber;
Noble talc- transparent light.

Talc, Switzerland Talc, Switzerland Talc crystal Talc in the mine

Origin

It is formed by the metamorphosing effect on magnesium silicates (, pyroxenes, amphiboles, mica, chlorites) and aluminosilicates of hydrothermal waters containing carbon dioxide and silica. Dolomite layers are transformed into talc under the influence of hydrothermal waters. The mineral is also formed at great depths under the influence of high pressure. Stone of this origin is found in crystalline schists (talc, talc-mica, talc-chlorite and other schists). It is found among serpentinites, crystalline shales, limestones, dolomites, magnesites and shales. In the absence of foliation, massive talc rocks are called talkites. Often contains small impurities of iron, nickel, manganese, chromium.

Satellites. Serpentine, magnesite, ; chlorite, calcite, dolomite. Minerals, as a result of chemical changes, talc is formed: olivine, pyroxenes, amphiboles, serpentine, micas, dolomite.

Use of talc

Talc is used as an acid-resistant and fire-resistant material. It is also used in the paper, leather, textile (for bleaching cotton), rubber (as a filler and for dusting rubber products), cosmetics (in the manufacture of pastes, powders, ointments), paint (light-resistant and fire-resistant paints), food industry, in medicine (talc powder), in electronic technology. Soapstone - for electrical insulation and as decoration in jewelry.

Place of Birth

Deposits of talc are known in the Urals (Shabrovskoye deposit near Yekaterinburg, in the Miass region, Medvedevskoye in Chelyabinsk region etc.), in the Kemerovo region (Alguyskoye field), in Karelia, Kazakhstan (Almalyk).

Talc crystals.

Talc, since it reduces friction, is used to a limited extent in elite sports - weightlifting, artistic gymnastics and rock climbing (primarily in sports). In sports, talc is used mainly for training purposes (to prevent the formation of calluses and abrasions), and during competitions, to improve hand grip on the apparatus in these disciplines, athletes use dry or liquid magnesium mixtures - 4MgCO 3 *Mg(OH) 2 *4H 2 O.

Talc is used in many dietary supplements and medications (for example, calcium gluconate) as a source of magnesium and silicon.

It is an ingredient in cosmetic powder.

It is used as a filler in rubber, paper, paint and varnish, medical (tablet base), perfumery and cosmetics and other industries.

An important area of application is ceramics (especially radio-insulating).

It is found in additives to motor oils to increase the service life and protect the internal combustion engine. [ ]

In the plastics industry - as a nucleator (nucleating additive), which allows to reduce the crystallization cycle time of polymers and improve their physical and mechanical properties. [ ]

Mining and production

During the Soviet era, the Shabrovskoye talc-magnesite deposit in the Middle Urals and the Miass talcite deposits in the Southern Urals, the Onotskoye steatite talc deposit (Eastern Sayan), the Kiryabinskoye deposit, the city of Uchaly were developed, and geological exploration of the Western Baikal talc-bearing province was carried out.

Large deposits of talc are located in Canada (Maydoc), USA (Gavernur), France (Luzenac).

Danger

There is a possibility that inhalation of talc dust may cause

It is often said that talc is the most common material. This happens because it is used in many areas of human activity. The range is actually wide: from industry to medicine. Sometimes when mining you come across stone talc, that is, coarse-grained, it is often called steatite. For reference, see photo.

Talc is the most common material

This name came to us from Arabic. It is a friable substance, essentially a powder. Sometimes they say that it feels greasy (otherwise oily) and very soft. More often white, but it can also be greenish, this is the norm. It is believed that the higher the quality of the talc, the whiter it is. Of course, talc used for industrial purposes is of rather low quality, often gray or gray-green, dirty in color. The shine of talc is called pearly.

Origin

The mineral talc has a crystalline (usually rhombic) structure. In nature it occurs in the form of leafy granular layers. It is a secondary mineral that is formed when magnesium silicates, which do not contain aluminum (Al), change their chemical composition.

We are talking about these two substances:

pyroxene;
amphibole.

In other words, the crystal structure remains the same, but the chemical composition undergoes significant changes. After the substance is extracted, it is crushed, most often this is done even for industrial purposes. There are many varieties of this mineral. For example, Minnesotaite contains a large amount of iron. Willemseite is nickel based. Here are these and other types:

soapstone;
agalite;
Minnesotait;
steatite;
Willemseit.

It should be noted that steatite is also often called wen, because it has increased density and mass. Soapstone chlorite is half talc.

Properties of the mineral

It should be mentioned that the material is never 100% pure, unless, of course, special processing is carried out; various impurities always occur:

iron;
aluminum;
calcium;
magnesium;
nickel.

There are other inclusions, but they already occupy hundredths of a percent, so there is little point in listing them. Some mineral plates are translucent. The cleavage is perfect. Hardness: 1 on the Mohs scale. It should be added that the mineral is in the very last place in this table. Density - 2.7 g/cm3. Inert towards acids and alkalis. This property is actively used in industry when talc is used.

Cosmetic use

As noted, talc is used very widely. The question of why talc is needed disappears by itself, since it is present everywhere in our lives. A separate article is the use of the substance at home. For example, newborns are treated with flavored talc (baby talc).

Girls use the substance for sugaring, that is, to remove hair on their legs. By the way, the word “sugaring” comes from the word “sugar”, so it is not entirely correct to use it for talc.

We are talking about the use of talcs in cosmetics, but we must remember that before using this or that product, you need to read the description of the drug. After which you can safely use it. Of course, men's use of talcum powder also occurs. For example, in sports.

It is quite difficult to replace talc here, since it absorbs water well, and synthetic powders can contain allergens and irritate the skin. It can be summarized by the fact that the most often used is crushed mineral powder. Talc for the body is very good, it produces a positive effect and does not allow moisture to leave the skin.

Industrial Application

Of course, the material can be used in everyday life as shoe powder to protect things. It is used in many areas: paint and varnish, rubber, etc. Tailor's chalk, French chalk is also talc. The material is a good electrical and thermal insulator. It covers electrical panels, pipes and other communication elements.

The material is also used in the finishing industry. Some interiors are decorated with talc. Ornaments are being made. It has good radio insulation, due to which it is used in the radiosphere. Used in the manufacture of plastics. Added to engine oil additives. It is even used in the food industry: look for additive E553 on the labels.

Extraction

There are several large deposits of the mineral in the world. It is believed that North America is in this sense the richest place. The substance is being developed by the USA and Canada. In Europe, the mineral is rarer; it is mined only in France. There are also mining areas in our country, mainly in the Urals, southern and northern.

Warning

Scientists around the world are studying the mineral, and in some cases their conclusions are disappointing: talc is not always useful. If you regularly inhale mineral dust, you can get the disease talcosis. Some people working for industrial enterprises, where talc is actively used, suffer from this disease.

Oncologists sometimes talk about the fact that the mineral can act as a carcinogen that contributes to the development of cancer. This dire warning is not always justified, since in most cases negative impact the substance has no effect.

Magic properties

In some cases, talc is used to prepare a variety of potions. It is believed that their use will help restore beauty, youth, and freshness of feelings to women. Sorcerers also make various ointments and creams, which, according to them, rejuvenate the skin and smooth out wrinkles.

Although this is doubtful, in some cases such methods give significant results. Talc is not used as amulets, amulets and talismans, although incense bags with talc are sometimes used, but very rarely. The mineral is neutral to all zodiac signs.

Medicinal properties

Known medicinal properties mineral. Most doctors believe that it is useful and acts as an antiseptic. Used for anti-inflammatory properties. The history of medicine says that in war conditions, in those days when antibiotics were not invented, wounds were covered with talcum powder. At the same time, the risk of gangrene decreased several times. Of course, this method is now outdated and not used. Of course, it is not recommended to pour it into an open wound.

Despite this, you can use talc-based powders. First of all, it is used by those who have delicate skin: girls, children. It relieves irritation and cleanses pores.

You won't find a cheaper solution these days. Some doctors practice using talcum powder internally, but you should not experiment with this yourself. Perform all actions under the supervision of your attending physician. Only in this case can your safety and health be guaranteed.

Talc formula Mg3*(OH)2

Talc forms leafy, scaly or solid dense masses. Individual crystals are rare.

Talc. Solid masses

Color white, light green, light yellow. The line is white. The luster is glassy, greasy, sometimes pearlescent. Standard hardness - 1. Density 2.8. The cleavage is very perfect (in one direction). The fracture is uneven. Other properties: greasy to the touch; leaflets, split off at the cleavage, are flexible but inelastic.

Varieties.
1. Wen (steatite) - dense granular talc.
2. Soap (potted) stone - a mixture of talc with chlorite and mica.

Diagnostics. Mica-like appearance, very perfect cleavage, green color. Easily recognized by its low hardness and fat content to the touch. It is similar to muscovite, but the latter has elastic-flexible leaves.

Satellites. Magnesite, hematite, chlorite, calcite, dolomite, serpentine, actinolite.

Origin. Formed by hydrothermal alteration of ultramafic rocks and dolomites, as well as by regional metamorphism clayey rocks. Talc, talc-actinolite and other shales are very widespread.

Application. In ground form, talc is used as a filler in paper, textile, rubber, leather, perfume and other industries. Lump talc is a fire-resistant material. Also used as a natural lubricant.

Talc - Mg3 (OH)2

Composition of talc

Chemical composition of talc.

Contains impurities of Fe (up to 2-5%), Al, Ca, Mn, Ni.

Origin of name. The name is ancient Arabic. origin. Synonym: steatite, or wen.

Morphological characteristics. Foliated and scaly aggregates (talc slate), star-shaped clusters, dense fine- and cryptoflaky rocks (talc stone, etc.), rarely fibrous masses (agalite) or tabular crystals, poorly faceted and easily split into thin plates and leaves.

The color in large leafy discharges is light green, sometimes white with a yellowish, brownish tint; It can be either colorless or quite thickly colored (brown and dark green). Darker tones are characteristic of dense, contaminated aggregates such as soapstone. The color intensity depends on the content of impurity elements (especially Fe) or the presence of iron hydroxides.

Thin plates of light, iron-free varieties are characterized by transparency or translucency.

The luster of leafy talc is glassy, with a pearlescent sheen on the cleavage planes; in dense masses - dull shimmering.

Properties of talc

Greasy to the touch.
The cleavage is very perfect; the adhesive leaves are flexible and slightly more elastic than those of pyrophyllite.
Hardness 1 (the lowest hardness standard on the Mohs scale); easy to draw with a fingernail and cut with a knife.
Specific gravity 2.6-2.8.
Inert towards acids and alkalis.

Talc deposits

Origin and distribution. Quite widespread. The chief rock-forming mineral of rocks called soapstone, soapstone, wen, soapstone, or potstone. Formed during hydrothermal processing of ultramafic rocks, dolomites or as a result of metamorphism of magnesium-rich sedimentary rocks.

Satellite minerals:

In deposits associated with ultrabasic rocks - serpentine, carbonates (magnesite, sometimes ankerite, dolomite, calcite), also chlorite, actinolite (less commonly tremolite), iron oxides (magnetite, hematite), pyrite, residual chromite group minerals, tourmaline, apatite, epidote, fuchsite (green chromium-containing muscovite); in deposits associated with hydrothermal alteration or metamorphism of dolomites and dolomitic limestones (marbles) - calcite, dolomite, quartz, sometimes serpentine, thermolite. Deposits in the Urals: Shabrovskoye, Nizhne-Isetskoye and others in the Sverdlovsk region, also in the Miass district of the Chelyabinsk region.

Stable on the surface of the earth; during hydrothermal alteration it can transform into a mixture of magnesite and quartz.

Diagnostic signs. It differs from aggregates of micas, hydromicas, and clay minerals by its very low hardness, pearlescent luster on the planes of perfect cleavage in leafy secretions, light color, fat content to the touch, and also by the association of minerals and rocks. It differs from pyrophyllite by chemical reactions (see pyrophyllite).

Practical significance. Iron-free, finely ground talc is widely used for medical and hygienic purposes; in perfumery and cosmetics; also as a solid lubricant; in ceramic production. Talc powder is used as a filler in the manufacture of rubber, paper, paints, soap, soft pencils for glass, metal, and fabric; in textiles as a bleaching material for cleaning cotton; for electrical insulators in high voltage networks; in the production of glazes, acid- and alkali-resistant vessels, drainpipes. Soapstones, especially those containing magnesite, combine fire-resistant, acid- and alkali-resistant, heat- and electrical-insulating properties.

Table. Chemical composition and physical properties of talc for the cable industry.

Index	Standard for talc brands		Test method
Index	TKV	TK1	Test method
1. Mass fraction of iron compounds soluble in hydrochloric acid, calculated as iron oxide (Fe 2 O 3), %, no more	0,5	0,6	GOST 19728.4-2001 Talc and talcomagnesite. Determination of iron oxide GOST 19728.4
2. Mass fraction of iron extracted by magnet, %, no more	0,02	0,04	GOST 25216-82 Talc and talcomagnesite. Method for determination of iron GOST 25216
3. Mass fraction of calcined residue insoluble in hydrochloric acid, %, not less	90	90	GOST 19728.1-2001 Talc and talcomagnesite. Determination of residue insoluble in hydrochloric acid GOST 19728.1
4. Mass fraction of water-soluble substances, %, no more	0,2	0,2	GOST 19728.12-2001 Talc and talcomagnesite. Determination of water-soluble salts GOST 19728.12
5. Mass fraction of Cl ions in aqueous extract, %, no more	0,01	0,01	GOST 19728.13-2001 Talc and talcomagnesite. Determination of chlorine ions in aqueous extract GOST 19728.13
6. Mass fraction of SO 4 ions in aqueous extract, %, no more	0,01	0,01	GOST 19728.14-2001 Talc and talcomagnesite. Determination of sulfate ions in aqueous extract GOST 19728.14
7. Mass fraction of manganese oxide (MnO), %, no more	0,01	0,01	GOST 19728.9-2001 Talc and talcomagnesite. Determination of manganese (II) oxide GOST 19728.9
8. Mass fraction of copper (Cu), %, no more	0,003	0,003	GOST 19728.10-2001 Talc and talcomagnesite. Determination of copper GOST 19728.10
9. Weight loss on ignition, %, no more	7	7	GOST 19728.17-2001 Talc and talcomagnesite. Determination of weight loss during ignition GOST 19728.17
10. Mass fraction of moisture, %, no more	0,5	0,5	GOST 19728.19-2001 Talc and talcomagnesite. Determination of moisture GOST 19728.19
11. Grinding fineness:			GOST 19728.20-2001 Talc and talcomagnesite. Determination of particle size distribution GOST 19728.20
remainder on the grid, %, no more:
№014	Absent
№009	-	2
№ 0045	3	-