What is cobalt

Persimmon: benefits and harm to the human body, chemical composition and calorie content, tips for use

Persimmon is a plant of the ebony family with edible orange fruits. This fruit is not only tasty, but also healthy. It contains dietary fiber, vitamins, minerals, carbohydrates, flavonoids that the body needs. Everyone should know what persimmon looks and grows, the benefits and harms of its fruits for the human body.

What is persimmon and where does it grow?

This plant belongs to the evergreen trees and shrubs. It comes from tropical countries. Features of this plant include:

absence of terminal kidneys;
the presence of simple leaves with translucent glands;
the presence of 4 or more stamens in flowers;
the presence of a dense, slightly viscous heavy fruit measuring 5-10 cm with thick skin;
the presence of seeds in the fruit (from 1 to 10).

It can be found in China, Central American countries, Russia, Turkey, Azerbaijan, Georgia and some European countries (Portugal, Spain, Italy). Persimmon is cultivated in Australia and America to obtain valuable and tasty fruits. Warm and hot climates are most favorable for tree growth.

persimmon is an evergreen tree of the ebony family with tasty and healthy orange fruits

Varieties of persimmon

The following varieties of persimmon have been identified:

Kinglet.
Honey.
Chocolate.
Fig.
Sharon.
Tomato.

According to taste characteristics, the fruit is divided into tart, sweet and king varieties. Based on the speed of fruit ripening, early-ripening (early), mid-ripening and late varieties (bearing fruit in autumn) are distinguished.

Chemical composition and calorie content

The composition of persimmon fruits includes the following substances:

Alimentary fiber. Promote normal intestinal motility, improve digestion and reduce the risk of developing malignant tumors (cancer).
Beta carotene. A pigment found in all yellow and orange fruits. It is a strong antioxidant (slows down the aging process of cells and protects the body from free radicals).
Complex carbohydrates. They form the basis of the fruit. They are sources of energy for humans.
Plant proteins. There are 0.5 g of them in 100 g of product. They contain amino acids necessary for the construction of cells, the formation of hormones, enzymes and other biologically active substances. They perform construction, protective, motor, enzymatic, receptor and other functions. Persimmon leaves do not contain protein.
Organic acids (citric, malic). There is 0.1 g per 100 g of fruit.
Water. It makes up the bulk of the product (81.5 g of water per 100 g of pulp).
Ash.
Vegetable fats, including omega-3 and omega-6 polyunsaturated fatty acids.
Vitamins.
Microelements (boron, cobalt, iron, nickel, molybdenum, selenium, manganese, zinc, fluorine, chromium, vanadium, iodine, aluminum, etc.).
Macroelements (sulfur, magnesium, calcium, potassium, chlorine, phosphorus, sodium).

persimmon fruits have concentrated in their composition a lot of biologically active components necessary for a person to maintain health

Vitamins. The role of iodine in persimmon

The benefit of persimmon is that its fruits are rich in vitamins. Contains:

Ascorbic acid (vitamin C). Strengthens blood vessels, participates in the formation of hemoglobin and promotes the absorption of iron by the body, participates in the synthesis of collagen (connective protein), strengthens gums and improves immunity. 100 g of product contains 15 mg of vitamin C.
Retinol (vitamin A). It has a positive effect on the organs of vision, improves color perception, supports the immune system, has an antioxidant effect, promotes the embryonic development of the fetus and is involved in hematopoiesis.
Thiamine (B1). Necessary for normal functioning of the nervous system. thiamine in persimmon 0.02 mg.
Riboflavin (B2). Participates in fat, protein and carbohydrate metabolism. In 100 g of fruit there is 0.03 mg.
Pantothenic acid (B5). Participates in the synthesis of corticosteroids, antibodies and neurotransmitters. Promotes the formation of fatty acids and improves intestinal motility.
Folic acid (B9). Participates in the formation of blood cells, amino acids, choline and nucleic acids (DNA, RNA).
Pyridoxine (B6). Participates in the formation of enzymes and protein metabolism (affects the metabolism of essential amino acids).
Choline (B4). It is a building material for the neurotransmitter acetylcholine, which promotes the conduction of nerve impulses.
Tocopherol (vitamin E). Powerful antioxidant. Helps strengthen the ligaments, muscles and tendons.
Vitamin K (phylloquinone). Shows antihemorrhagic properties (prevents bleeding).
Niacin. Participates in redox processes.

Caucasian persimmon - the fruit is a valuable source of iodine. This element promotes the growth and development of the child's body. Iodine performs the following role:

promotes the growth and development of all organs and systems;
regulates heart function (heart rate, blood pressure);
is a structural material for thyroid hormones (thyroxine and triiodothyronine);
maintains normal hormonal levels;
regulates energy metabolism;
helps maintain body temperature;
promotes tissue oxygenation;
participates in the most important biochemical reactions;
affects vitamin metabolism;
regulates protein, fat and carbohydrate metabolism;
improves mental activity.

100 g of fruit contains 60 mcg of iodine (this is almost half the daily requirement).

the fruit has high nutritional value, but low calorie content

Nutritional value per 100 grams

An important property of persimmon is its low calorie content. This is due to the fact that it consists mainly of liquid. 100 g of product provides 67 kcal of energy.

Beneficial features. When and to whom is persimmon useful?

The product has the following effects on the human body:

improves vision;
strengthens muscles;
has a beneficial effect on the mucous membrane of the stomach and intestines;
normalizes stool (helps get rid of constipation);
slows down the aging of the body;
normalizes sleep and psycho-emotional state;
prevents the development of atherosclerosis;
has an anticarcinogenic effect;
reduces inflammatory processes in the body;
reduces the risk of developing cardiovascular pathology;
has a disinfectant effect, killing pathogens of intestinal infections;
strengthens blood vessels;
supports the functioning of the thyroid gland;
reduces the risk of developing urolithiasis;
increases immunity;
reduces the risk of developing anemia.

Korolek persimmon is good for children, men and women.

the fruit has a beneficial effect on women's health and beauty

Particular effect on the female body

The fruit is especially useful for pregnant women. The substances it contains promote the full development of the fetus, improve metabolic processes and mood, and relieve swelling. You can make face masks from this fruit. They help cope with dry skin and rashes.

Uses of persimmon

The fruit can not only be eaten raw, but also used dried or baked. It is widely used in cooking (baking and making desserts), dietetics and medicine.

Dried persimmon

Not everyone knows the benefits of dried persimmons. There is practically no water in it, only useful substances. It is superior in calorie content to the raw product. Eating fruit on an empty stomach helps reduce coughing and remove toxins and toxic substances from the body. Compotes are prepared from dried fruit, which are much healthier than sparkling water and coffee.

Application in medicine and dietetics

Everyone should know what persimmon tastes like, its beneficial properties and contraindications for consuming the product. Its fruits are widely used in dietetics. They are included in the menu for people who are trying to lose excess weight. It is better to eat fruits in the first half of the day. This fruit is also suitable for fasting days. Despite the high sugar content, people who regularly eat the fruit do not gain weight. This is due to the fact that the carbohydrates there are not simple, but complex. They are more useful.

Due to the great benefits of persimmon for the body of women and men, it is used in folk medicine. The fruit is used during the rehabilitation period after serious illnesses and operations, for visual impairment, respiratory diseases, hemorrhoids and even parasitic infections. The fruits are useful for urolithiasis. Persimmon helps almost everyone against constipation.

the fruit is used in cooking as a sweet and dessert

In cooking

This delicious fruit can replace confectionery products (sweets, cakes, pastries). It is much healthier than sweets. The fruit is often added when making cakes. The pulp is added to ice cream, soufflé and cream. Pieces of the fruit can be placed in baked goods. The fruit is also used as a decoration for dishes.

Not everyone knows what not to eat persimmons with. The fruits of this plant are not recommended to be consumed simultaneously with milk, dairy products, fish and seafood. To reduce the negative impact of fruit on the digestive organs, it is better to choose fruits that are not astringent.

Use of persimmon in industry

You need to know not only the medicinal properties and contraindications, how much fruit you can eat, but also how the plant is used in industry. It is a source of valuable wood. The wood of this plant is used to make sports equipment, musical instruments and even furniture.

Useful and medicinal properties of leaves, roots and shoots

Leaves, roots and shoots are used in folk medicine. They have antiseptic, anthelmintic, antibacterial, anti-inflammatory and restorative effects. Infusions and decoctions are prepared from them. First, the raw materials are dried and crushed, then poured with boiling water. Dry stalks help with hiccups. Persimmon seeds are also edible. They can be consumed dried, raw or fried.

The rich chemical composition of persimmon allows it to be used for cosmetic purposes for facial skin care

Application in cosmetology

The substances contained in the fruit allow it to be used as a cosmetic product. Prepared from the plant:

Lotions. Suitable for people with dry skin. Take olive oil and mix it with the juice of the fruit. The resulting mass is applied to the facial skin for 15-20 minutes. The vitamins in persimmon improve the condition of the skin, make it more elastic, and prevent the early appearance of wrinkles.
Nourishing and moisturizing masks. Prepared on the basis of milk, fruits, eggs, honey and aloe juice. The procedure lasts about 30 minutes. It is recommended to do masks several times a day. To do this, you don’t need to visit a cosmetologist and spend money. Black persimmon is used at night to moisturize and nourish the skin of the face and hair.
Scrubs. Helps clean out pores in the skin.

Contraindications. What you should know

The fruits of this plant are not suitable for diabetics, as they contain a lot of sucrose and other carbohydrates. If you have diabetes, you should not eat dried fruits. It is not recommended for nursing women to consume the fruit due to the possibility of the child developing an allergy in the form of diathesis.

Despite the beneficial properties of persimmon, it is best not to give it to young children (under 3 years old). The fruit can cause gastrointestinal disorders.

When choosing a fruit, it is better to give preference to ripe fruit without signs of spoilage

How to select and store persimmons

Fruits are chosen when they are ripe. The fruit should be dense, soft, without signs of spoilage or rot. Dark flesh indicates that the fruit is sweet. If the fruit is too hard, it will be less tasty. Such fruits are very astringent in the mouth. A crust that is too light indicates that the product is not yet ripe. Store fruits in a cool, dry place.

Source: https://narodzdorov.ru/lekarstvennye-rasteniya/hurma-polza-i-vred.html

Cobalt is a chemical element. Cobalt in the human body

An ordinary person not connected with chemistry and medicine, as a rule, has a vague idea of the importance of cobalt for his life and health. Another reason why we find it difficult to explain what cobalt is is its scarce distribution in nature.

Only 0.004% - this is its content in the earth’s crust. However, the metal and its compounds are actively used in metallurgy, agriculture and medicine.

In our article we will expand our understanding of the role of cobalt in industry, and also dwell on its functions in the human body.

Place of the element in the periodic table

What place does cobalt occupy in the periodic table? The properties of chemical elements, including the metal we are considering, depend on their position in D.I. Mendeleev’s table. It is located in group VIII b (in the short form of the table - in the iron triad of group VIII).

Like iron and nickel, its atom has two electrons at the last energy level, which indicates that the metal belongs to d-elements and determines its main characteristics. The metal has two valences – II and III.

It is also characterized by the phenomenon of allotropy; modifications of the metal can have a cubic or hexagonal structure.

What are the physical properties of the element? In appearance it is a metal with high hardness and magnetic properties.

Silvery luster, ductility and thermal stability are some other physical characteristics of the element, also inherent in its two other neighbors on the periodic table - nickel and iron. Neither oxygen nor water affects cobalt at ordinary temperatures.

Its compounds, for example, smalt, have been known since ancient times as substances used to produce blue stained glass and color ceramic products.

Cobalt is a typical metal, similar in its chemical properties to iron. What are the features of its oxides, bases and salts?

Compounds of divalent and trivalent cobalt

The ability to form complex salts is the main distinguishing feature of Co(III) atoms. These substances are unstable; the cobalt coordination number in them is always six. They have high oxidizing capacity. Medium salts, for example, CoCL3 or Co2(SO4)3, easily transform into salts in which cobalt is already a divalent metal.

Its anhydrous compounds are blue in color, while crystalline hydrates and solutions are pink. Unlike other bases, trivalent cobalt hydroxide, when interacting with chloride acid, does not form salt and water, but releases free chlorine from it. The divalent metal base in the form of a blue precipitate is obtained by direct reaction of the corresponding salt with an alkali.

Let us give a description of the properties of cobalt, which is part of solid solutions of metals in each other - alloys.

It gives the material exceptional technical parameters of resistance to high temperatures, hardness, abrasion and corrosion resistance. Alloys containing cobalt are used in the defense industry, rocketry and closed-cycle chemical technologies.

In the production of tool steels and materials with magnetic properties, cobalt is also used as an alloying additive. The properties of such iron alloys are very different from conventional stainless steels containing only chromium or nickel.

Application of cobalt in technology

About a third of all metal produced in the world goes into the production of cermets - artificial composite materials. The solid base in them is tungsten carbide, and the binding and fixing component is cobalt. It is also a strategic raw material for the production of engine turbines in aircraft manufacturing.

In its pure form, the metal is practically not used, but the use of cobalt in a mixture with other elements (iron, copper, tungsten and chromium) is widespread in various industries. Stellite alloy, containing up to 60% cobalt, is characterized by increased heat resistance and hardness; it is an indispensable material for the manufacture of cutters and drills in tool production. Alloying elements such as tungsten and molybdenum enhance its characteristics.

Vitalium alloy, which has high resistance to plastic deformation, also contains cobalt. The properties of the compound are as follows: heat-resistant and acid-resistant, used in the manufacture of chemical equipment: synthesis columns, distillation apparatuses.

The role of alloys in counteracting various types of corrosion is great, for example, parts and mechanisms made of stellite resist destruction during oscillatory and rubbing movements of mechanical surfaces in internal combustion engines.

Methods for obtaining cobalt

Various sectors of the economy require the use of materials containing cobalt. This helps to increase the production of ores and minerals, namely cobalt specie and glitter.

These rocks also contain arsenic, which forces the use of increased safety measures in metal smelting processes. The main method of obtaining cobalt is pyrometallurgy; the method of treating ore with sulfate acid is also used.

The most promising deposits are considered to be deposits of silicate-oxide ores, pyrite and pentlandite in China, Russia (on the Kola Peninsula, the Republic of Tuva and the Krasnoyarsk Territory), as well as in Canada.

Application of metal in agriculture and medicine

Certain important properties possessed by the microelement cobalt facilitate its use, for example, in crop production to increase the vegetative mass of plants. In alfalfa, lupine, clover and other valuable forage grasses of the Legume family, it is included in enzymatic nitrogen fixation reactions occurring with the help of nodule bacteria.

A deficiency of a microelement is manifested by symptoms such as discoloration of leaf blades and loss of their ability to photosynthesize, a slowdown in growth processes and disruption of the entire development cycle of the plant. Excessive cobalt content is possible due to violation of microfertilizer application standards.

Since its compounds are highly soluble in water, they immediately enter the xylem and, through conductive elements (vascular-fibrous bundles), enter the mesophyll of the leaf, causing their discoloration and wilting. The most sensitive to excess microelement are cereal crops: oats, barley, rice.

Biochemistry on the role of cobalt compounds

The branch of biology that studies living matter at the molecular and cellular level has established the important function of this chemical element. It is part of the non-protein part of biologically active substances - enzymes and hormones. For example, cobalt in the human body is found in thyroxine molecules produced by the thyroid gland and controlling metabolic processes.

Another vital hormone that regulates plasma glucose levels is insulin. It is secreted by the β-cells of the islets of Langerhans of the pancreas and also contains cobalt compounds. Insufficient supply of the element to human cells and organs is observed during the transition from a mixed diet to vegetarianism, with helminthic infestations and diseases of the digestive system.

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As you can see, cobalt is a trace element that seriously affects the level of homeostasis in the human body.

The importance of a chemical element in metabolism

Hematopoiesis, carried out by red bone marrow, occurs with the participation of cobalt-containing substances - activators of the corresponding enzymes.

One of the main B vitamins - cyanocobolamin (B12), participating in the formation of red blood cells in the hematopoietic organs, protects the body from anemia.

A proper and balanced diet containing liver, beef, seafood, dried apricots, and beets will provide the necessary level of cobalt in the human body (about 40 mg per day) and protect it from diseases of the immune, cardiovascular and endocrine systems.

Source: https://FB.ru/article/318448/kobalt-eto-himicheskiy-element-kobalt-v-organizme-cheloveka

Cobalt No. 27 chemical element

Several hundred years ago, the German province of Saxony was a major center for the extraction of silver, copper and other non-ferrous metals at that time. In the local mines it happened that ore was found that, by all external signs, seemed to be silver, but when smelting it was not possible to obtain the precious metal from it. Worse, when such ore was roasted, poisonous gas was released, poisoning workers.

The Saxons explained these troubles as the intervention of evil spirits, an insidious underground gnome, a kobold. From him came other dangers that lurked for miners in the dungeons. In those days in Germany, prayers were even read in churches to save miners from the evil spirit of the kobold. And over time, when the Saxons learned to distinguish “impure” ore from silver, they called it “kobold.”

In 1735, the Swedish chemist Georg Brandt isolated an unknown gray metal with a faint pinkish tint from this “impure” ore. The name “kobold” or “cobalt” remained with him.

From Venetian glass to traffic lights

Brandt's dissertation on the new metal stated, in particular, that the metal could be used to make safra, a paint that gives glass a deep and very beautiful blue color. But even in Ancient Egypt, blue glass was known, made according to carefully hidden recipes.

In the Middle Ages, none of the European states could compete with the Venetian Republic in glass production. In order to protect the secrets of melting colored glass from the curiosity of others, the government of Venice in the 13th century. by special decree transferred all glass factories to the secluded island of Murano.

You can get some idea of the ways in which production secrets were protected there from this history. One day, an apprentice named Giorgio Bellerino fled from the island, and soon a glass workshop burned down in one of the German towns.

Its owner - his name was Belerino - was stabbed to death with a dagger

And yet, despite such cruel measures, the secrets of melting colored glass became known in other countries. In 1520, Weidenhammer in Germany found a way to prepare paint for blue glass and began selling it at an expensive price. to the Venetian government! Another 20 years later, the Bohemian glassmaker Schurer also began making blue paint from some ore known only to him.

With his help, such paint began to be produced in Holland. Contemporaries wrote that glass was painted with “zaffer,” but no one knew what this product was. Only a century later (in 1679)

) the famous chemist Johann Kunkel described in detail the process of obtaining paint, but it remained unknown what kind of ore it was made from, where to look for this ore and what component of it has the coloring property.

Only after Brandt’s research it was discovered that safr, or tsaffer, a product of calcination of ore rich in cobalt, contains cobalt oxides and many oxides of other metals. Tsaffer, then fused with sand and potash, formed smalt, which was paint for glass. Smalt contained little cobalt - only 2-7%. But the coloring power of cobalt oxide turned out to be great: already 0.0001% of it in the charge gives the glass a bluish tint.

Glassmakers of the Middle Ages used the properties of cobalt unconsciously, having found them purely experimentally. Of course, this cannot even in the slightest degree detract in our eyes from the wonderful art of these workers.

In addition to smalt, there are other cobalt dyes: blue aluminum-cobalt paint - tenar blue; green - a combination of oxides of cobalt, chromium, aluminum, magnesium and other elements. These paints are beautiful and quite durable at high temperatures, but do not always have good covering power. Their value is much less than smalt. Something else deserves attention: the variability of the color of cobalt compounds.

The miracles of color transformation have been known since the 16th century. Paracelsus, a professor at the University of Basel, a chemist and physician, showed a painting he himself had painted. She depicted a winter landscape - trees and hills covered with snow. After letting the audience see enough, the professor slightly warmed up the picture, and right before everyone’s eyes, the winter landscape was replaced by a summer one: the trees were putting on leaves, the grass was turning green on the hills. It gave the impression of a miracle.

For a modern chemist, the story of Paracelsus' painting looks quite simple. This effect could be achieved, in particular, by cobalt paints. Cobalt chloride , to which an appropriate amount of nickel chloride has been added, is almost colorless. But when heated, these salts lose their water of crystallization, and their color changes.

In 1737, a French chemist discovered the property of cobalt salts to color under the influence of heat and used them as sympathetic ink. What they write on paper becomes visible only after the paper is heated. Now this feature of cobalt salts is of practical importance in laboratory technology: porcelain crucibles are labeled with a solution of cobalt salts. After heating, such a mark clearly appears on the white surface of the porcelain.

Cobalt as a dye

Coloring glass with cobalt compounds is of no small importance in our time, although there are cheaper dyes. For technical purposes, glass is often needed that absorbs and transmits rays of a certain color. Such glasses are necessary in photography, signaling, colorimetric analysis and other cases. Nowadays, smalt is not used, but cobalt oxide is used directly, which is added to the mixture loaded into a glass melting furnace.

Glass used for signal lights must produce a sharp, distinct light. It is necessary to exclude the possibility of erroneous perception of the signal even in conditions of poor visibility, even at high transport speeds and imperfect human vision. And for this it is necessary that the glass of the light signaling devices transmits only light of a wavelength of a precisely defined length.

Glass colored with cobalt oxide has no rivals in terms of transparency, and the addition of minute amounts of copper oxide to such glass gives it the ability to block some rays of the red and violet part of the spectrum.

For photochemical studies, glass may be needed that does not transmit yellow and orange rays at all.

Cobalt-ruby glass meets this condition: blue glass colored with cobalt is superimposed on heated glass colored red with copper compounds - the so-called copper ruby.

The use of cobalt oxide is well known to impart a beautiful, very durable dark blue color to porcelain and enamel products.

Cobalt is an alloying metal

In 1912 they wrote about cobalt: “Until now, metallic cobalt is of no interest from the point of view of consumption. There have been attempts to introduce cobalt into iron and prepare special steels, but the latter have not yet found any application.”

Indeed, at the beginning of this century, the first attempts to use cobalt in metallurgy were unsuccessful. It was known that chromium, tungsten, and vanadium give steel high hardness and wear resistance at elevated temperatures.

At first, the impression was that cobalt was not suitable for this purpose - the steel was poorly hardened, or more precisely, the hardening penetrated into the product to a very small depth. Tungsten, chromium and vanadium, combining with carbon dissolved in steel, form solid carbides, while cobalt, as it turns out, promotes the release of carbon in the form of graphite.

At the same time, the steel is enriched in unbound carbon and becomes brittle. This complication was later eliminated: adding a small amount of chromium to cobalt steel prevents graphitization; This type of steel can be hardened well.

Now cobalt, like tungsten, is indispensable in metalworking - it serves as the most important component of high-speed tool steels. Here, for example, is the result of comparative tests of three incisors.

The steel from which they were made contained equal amounts of carbon, chromium, vanadium, tungsten and molybdenum, the only difference being the cobalt content. In the first, vanadium steel, there was no cobalt at all, in the second, cobalt, it was 6%, and in the third, supercobalt, 18%.

In all three experiments, a steel cylinder was sharpened with a cutter. The thickness of the removed chips was the same - 20 mm, the cutting speed was also 14 m/min.

What did the experiment show? The vanadium cutter became dull after traveling 7 m, the cobalt cutter after 10 m, and the super cobalt steel cutter went dull after 1000 m and remained in good condition! Thus, in order to dramatically increase the wear resistance and cutting properties of steel, cobalt must be included in its composition in significant quantities.

In 1907, hard alloys that did not contain iron - stellites (from the Latin word Stella - star) appeared in industry. One of the best stellites contained more than 50% cobalt.

And in hard alloys, which in our time have become the most important material for metal-cutting tools, cobalt plays an important role. Tungsten or titanium carbide, the main component of the hard alloy, is sintered in a mixture with cobalt metal powder.

Cobalt connects the grains of carbides and gives the entire alloy greater viscosity, reducing its sensitivity to shocks and impacts.

Carbide alloys can be used not only for the manufacture of cutting tools. Sometimes it is necessary to weld a hard alloy onto the surface of parts that are subject to severe wear during machine operation. This cobalt-based alloy can increase the service life of a steel part by 4-8 times.

Magnetic properties of cobalt

The ability to retain magnetic properties after a single magnetization is characteristic of only a few metals, including cobalt. The steels and alloys from which magnets are made are subject to a very important technical requirement: they must have a high coercive force, otherwise they must have resistance to demagnetization. Magnets must be resistant to temperature influences, vibration (which is especially important in motors), and easy to machine.

When exposed to heat, a magnetized metal loses its ferromagnetic properties. The temperature at which this occurs (Curie point) is different: for iron it is 769°C, for nickel it is only 358°C, and for cobalt it reaches 1121°C. Back in 1917, a steel composition with improved magnetic properties was patented in Japan.

The main component of the new steel, called Japanese, was cobalt in very large quantities - up to 60%. Tungsten, molybdenum or chromium give magnetic steel high hardness, and cobalt increases its coercive force by 3.5 times. Magnets made from this steel are 3-4 times shorter and more compact.

And one more important property: if tungsten steel loses its magnetic properties by almost a third under the influence of vibrations, then cobalt steel loses by only 2-3.5%.

In modern technology, especially in automation, magnetic devices are used literally at every step. The best magnetic materials are cobalt steels and alloys. By the way, the property of cobalt not to demagnetize under the influence of vibrations and high temperatures is of no small importance for rocket and space technology.

Modern requirements for permanent magnets are extremely diverse. And one of the main things is minimum weight with maximum “strength”. In recent decades, such magnets have been invented. These are alloys called “magnico” and “alnico” - after the initial letters of the names of the metals from which they are composed: the first from magnesium, nickel and cobalt, the second from aluminum, nickel and cobalt.

Such magnets contain no iron at all - a metal whose very name we are accustomed to considering from school as inseparable from ferromagnetism.

The properties of these alloys seem extraordinary: a magnet weighing 100-200 g holds a load of 20-30 kg! Very strong permanent magnets are also obtained from intermetallic compounds of cobalt with some rare earth elements (for example, SmCo5, etc.)

Source: https://natural-museum.ru/chemistry/%D0%BA%D0%BE%D0%B1%D0%B0%D0%BB%D1%8C%D1%82

Cobalt (Co, Cobaltum)

There are many legends and legends associated with the history of the discovery of cobalt; in the Middle Ages, people were sure that there was some interference from evil spirits. It is not without reason that the name cobalt comes from the German Kobolt - a malicious dwarf, a little gnome who plotted all sorts of intrigues, preventing the miners of Saxony from mining ore and smelting metal.

Some ores mined in Saxony were silver in color and were initially considered to be silver. But the metal obtained from these ores gave off toxic fumes, which repeatedly poisoned miners (calorizator). In 1735, the Swedish chemist Georg Brandt isolated a silvery-pinkish metal from the “ore of evil spirits”, which was called kobold.

Subsequently, the name was transformed into one known and familiar to us.

General characteristics of cobalt

Cobalt is an element of group IX of period IV of the periodic table of chemical elements D.I. Mendeleev, with atomic number 27 and atomic mass 58.9332. The recognized designation for cobalt is Co (from the Latin Cobaltum).

Being in nature

Cobalt is not a very common metal; rather, it can be classified as rare; it is present in minimal quantities in the earth’s crust. There are no more than 30 minerals that contain cobalt. The largest cobalt deposit is located in the Democratic Republic of the Congo, and there are deposits in the USA, France, Canada and Russia.

Physical and chemical properties

Cobalt is a hard metal of a silvery-white color, with a slightly pinkish (less often blue) tint. When interacting with air, oxidation occurs at high temperatures (300˚C and above).

Daily requirement for cobalt

The daily requirement for cobalt is very small, usually 0.1 – 0.8 mg for a healthy adult. Typically, a person gets their daily dose of cobalt from food.

Foods rich in cobalt

Main sources of cobalt:

Signs of cobalt deficiency

Signs of a lack of cobalt in the human body are increased incidence of diseases of the circulatory and endocrine systems. The common cause of cobalt deficiency is chronic diseases of the digestive system (gastritis, duodenal ulcer).

Applications of cobalt in life

Cobalt has found wide application in the form of alloys - in the metallurgical industry to increase the heat resistance of steel, in the production of magnets, as a composition of dyes - in the production of glass and ceramics.

Beneficial properties of cobalt and its effect on the body

Cobalt is one of the vital microelements; its presence in the human body is mandatory. Cobalt is part of vitamin B12, takes part in the synthesis of DNA and amino acids, and in the breakdown of proteins, fats and carbohydrates. Actively influences the metabolic processes of the body, plays a special role in hematopoiesis - stimulates the growth and development of red blood cells. Cobalt supports normal pancreatic activity and regulation of adrenaline activity.

Source: http://www.calorizator.ru/element/co

Metal cobalt

Rolled metal calculator

Cobalt is a wear-resistant, heat-resistant metal, which determines its use as an alloying additive to steels and alloys in order to improve their properties, as well as a material for applying wear-resistant coatings. In addition, this metal is used in permanent magnets due to its high demagnetization resistance. The page provides a description of this metal: physical properties, applications, brands, types of products.

Cobalt (Co) (Cobaltum) is a chemical element of group VIII in the periodic table of chemical elements with atomic number 27, a hard, viscous, shiny bluish-gray metal, classified as a heavy metal. Density is 8.9 g/cm3, tmelt=1493 °C, tboil.

=2957 °C. In the earth's crust, the Co content is 4·10-3% by mass. This metal is part of more than 30 minerals. These include carolite CuCo2S4, linneite Co3S4, cobaltine CoAsS, spherocobaltite CoCO3, smaltite CoAs2 and others. In sea water approximately (1-7) 10-10% Co.

The name of the metal “Cobalt” is closely associated with the Saxon mines, and more precisely with the underground gnome Kobold, who lived there according to the Saxons. The fact is that the ore, then accepted as silver, did not always yield the precious metal directly when smelted. This phenomenon was precisely attributed to the evil deeds of the little gnome Kobold.

The ore, which did not produce silver, but was very similar in appearance to silver, was called “kobold”. Most likely, these were arsenic-containing cobalt minerals - cobalt CoAsS, or cobalt sulfides skutterudite, saflorite or smaltite. In 1735, the Swedish chemist Georg Brandt isolated an unknown gray metal with a faint pinkish tint from this ore, which was called “kobold” or “Cobalt”.

Brandt also found out that compounds of this particular element color glass blue.

Physical and mechanical properties

Property Meaning

Atomic number	27
Atomic mass, a.u.m	58,93
Atomic diameter, pm	250
Density, g/cm³	8,9
Specific heat capacity, J/(K mol)	0,456
Thermal conductivity, W/(m K)	100
Melting point, °C	1493
Boiling point, °C	2957
Heat of fusion, kJ/mol	15,48
Heat of evaporation, kJ/mol	389,1
Molar volume, cm³/mol	6,7
Group of metals	Heavy metal

Chemical properties

Property Meaning

Covalent radius:	130 pm
Ion radius:	(+6e) 62 (+4e) 70 pm
Electronegativity (according to Pauling):	2,16
Electrode potential:	0
Oxidation states:	6, 5, 4, 3, 2

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Cobalt and alloy grades

Modern industry produces several grades of this metal.

K0, K1Ay, K1A, K1, K2 - metallic cobalt, the Co content is no less than 99.98% for grade K0 and no less than 98.3% for K2. These grades are produced in the form of ingots, cathode sheets, strips and plates. The production method used is electrolysis or refining.
PK-1u - metallic cobalt with a content of the specified chemical element Co of at least 99.35%. This brand is produced in the form of a powder obtained by electrolysis.

has good heat resistance;
has high wear resistance and hardness, including at high temperatures;
has high resistance to demagnetization even at elevated temperatures and mechanical loads.

has a high cost.

Cobalt in powder form is used mainly as an additive to steels. At the same time, the heat resistance of steel increases and its mechanical properties (hardness and wear resistance at elevated temperatures) improve. This metal is part of the hard alloys from which high-speed tools are made. One of the main components of the hard alloy - tungsten or titanium carbide - is sintered in a mixture with cobalt metal powder. It is Co that improves the toughness of the alloy and reduces its sensitivity to shocks and shocks. For example, a cutter made of supercobalt steel (18% Co) turned out to be the most wear-resistant and has better cutting properties compared to cutters made of vanadium steel (0% Co) and cobalt steel (6% Co). Cobalt alloy can also be used to protect against wear the surfaces of parts subject to heavy loads. A hard alloy can increase the service life of a steel part by 4-8 times. It is also worth noting the magnetic properties of cobalt. This metal is able to retain these properties after a single magnetization. Magnets must have a high resistance to demagnetization, be resistant to temperature and vibration, and be easy to machine. The addition of cobalt to steel allows it to retain magnetic properties at high temperatures and vibrations, and also increases resistance to demagnetization. For example, Japanese steel, containing up to 60% Co, has a high coercivity (resistance to demagnetization) and loses its magnetic properties by only 2-3.5% during vibration. Cobalt-based magnetic alloys are used in the production of cores for electric motors, transformers and other electrical devices. It is worth noting that cobalt has also found application in the aviation and space industries. Cobalt alloys are gradually beginning to compete with nickel alloys, which have proven themselves and have long been used in this industry. Co-containing alloys are used in engines where fairly high temperatures are reached, and in aircraft turbine structures. Nickel alloys lose their strength at high temperatures (at temperatures above 1038°C) and are thus inferior to cobalt alloys.

Recently, cobalt and its alloys have begun to be used in the manufacture of ferrites, in the production of “printed circuits” in the radio engineering industry, and in the manufacture of quantum generators and amplifiers.

Lithium cobaltate is used as a highly efficient positive electrode for the production of lithium batteries. Cobalt silicide is an excellent thermoelectric material and allows the production of thermoelectric generators with high efficiency.

Co compounds introduced into glass during melting provide a beautiful blue (cobalt) color to glass products.

Modern industry produces a variety of products from cobalt. The most common types are cobalt powder, ingots and plates. Cobalt wire is also produced for special purposes.

These products are used in cases where a material is needed that has high wear resistance and heat resistance or high demagnetization resistance.

Source: https://www.metotech.ru/kobalt-opisanie.htm

Cobalt and its toxicity - harm and benefits of cobalt

Cobalt in its pure form has been known to man since the 18th century, but it has been used since time immemorial: in ancient Assyria and Babylon, glass was painted a beautiful blue color with the help of its compounds, and this use has not lost its significance today. In its pure form, cobalt is a beautiful metal of silvery-white color, which has either a yellowish or bluish-pink tint.

Cobalt color

The main use of cobalt in industry is alloying steels: its presence increases their durability and heat resistance. It is indispensable in the production of magnets; the cores of transformers and electric motors are made using cobalt alloys.

The cobalt-lithium compound is currently widely used to produce lithium batteries, which can be used as a direct current source for electric vehicles.

Its tetracarbonyl is used as a catalyst, and the organic stearate of this metal is used to produce plastics.

In addition to the stable isotope, there is also radioactive cobalt (Co-60), which is used in medicine in modern devices for neurosurgical operations and irradiation of hard-to-reach brain tumors, because the radiation power of only 17 g of this isotope is equivalent to a kilogram of radium.

Cobalt is used in modern gamma knives

Finally, cobalt is the only metal element that is part of vitamin B12, a cyanocobalamin essential for human life.

Vitamin B12

A deficiency of this element causes serious changes in the blood, causing pernicious anemia, from which people died at the beginning of the 20th century, but this metal also poses a known danger. It is included in the list of industrial poisons, and it was assigned, although not the first, but the “honorable” second class of danger. The toxicity of cobalt has been well studied, and there can be both acute and chronic poisoning from this element and its compounds. Let's give a historical example.

Death by beer

Cobalt salts (sulfate and chloride) were widely used in the food industry as beer foam stabilizers until it was discovered that the toxicity of cobalt salts was very high. Their use for this purpose in Western Europe and the USA in the 60s of the 20th century, as it turned out later, led to serious circulatory and cardiac disorders, and even caused fatalities with a whole chain of deaths.

Cobalt cardiomyopathy developed very quickly, especially in those individuals who drank large quantities of beer daily, more than three or four daily. There was even such a term - “beer cardiomyopathy”, or acute cobalt poisoning.

The patient develops shortness of breath, lactic acid accumulates in the blood, the heart rate increases, the ECG changes - it becomes low-voltage, which indicates a decrease in the electrical potential of the atria and ventricles, and mortality can reach 40% three days after intensive consumption of beer for several days.

Along the way, the vast majority of those who died were found to have a sharp depression of thyroid function.

After research, the use of cobalt salts to stabilize beer foam was prohibited.

Therefore, at present, it is possible to be poisoned by the element only if the concentration of cobalt dust in the air is more than 0.5 mg per cubic meter, and for drinking water the maximum permissible concentration of its salts is 0.01 mg per liter.

However, cardiomyopathy can also affect healthy young people working in the production of its hard alloys, and if safety rules are not followed, it can lead to death in our time.

How can you get poisoned by cobalt?

All acute and chronic poisonings with compounds of this metal, as well as with it itself, are almost exclusively found in production in our time. Cobalt can enter the body in all ways. Most often it penetrates through the respiratory system, in some cases through the skin (percutaneous - percutaneous route of infection), or alimentary, that is, entering the mouth.

The airborne route of infection most often occurs when working with various bulk materials that contain this metal. This most often occurs in factories associated with powder metallurgy technology.

All processes of sifting, unloading, unloading, calibrating powders for the production of cobalt-tungsten alloys can lead to these cases.

By the way, if a mixture of titanium and cobalt enters the body through the lungs, it causes a more pronounced toxic effect than each of these elements separately.

You can get poisoned when working with asbestos-cement products or liquid cement; this is a risk for concrete workers and plasterers. Since cobalt is used to create paints, there is a high risk of intoxication among painters, paint tinkers and glassblowers.

The toxic effect in acute form is reduced to damage to the bronchopulmonary system, especially the hematopoietic system, digestive and nervous systems. Let us consider the characteristic signs of acute and chronic intoxication with cobalt and its compounds.

Symptoms of acute poisoning

Both the benefits and harms of cobalt for the human body are obvious. At the same time, the symptoms of acute poisoning are quite scanty, and their main signs are not in complaints at all, but in laboratory data.

In addition to the symptoms of cardiopathy already described above, such as weakness, shortness of breath, tachycardia, cardiac arrhythmia, in acute poisoning, and especially with soluble cobalt salts, for example, its chlorides, various gastrointestinal disorders may occur, such as nausea and vomiting, as well as damage peripheral and central nervous system, leading to a decrease in proprioception.

What it is? Proprioception is the ability of a person to determine the position of his body in space with his eyes closed. With characteristic disorders of this type of sensitivity, which is also called joint-muscular sensation, the manifestation of so-called posterior columnar ataxia is possible. This affects the posterior columns of the spinal cord, which carry this specific type of sensation, and can manifest as sudden falls or changes in gait in the dark.

A person with this disorder must see his legs, and in the absence of lighting he cannot move, or this movement is very difficult, because he simply does not feel where his limbs are, and this process must be controlled visually. It is also possible to have a disorder of the vestibular apparatus, dizziness, and this is where the clinical symptoms of acute manifestations of cobalt salts end.

The main symptoms are laboratory indicators, for example, data from a general blood test. Against the background of acute poisoning, the hemoglobin level increases, the hematocrit, or blood thickening, increases and the number of red blood cells increases. In general, polycythemia occurs - many cellular elements, reticulocytes, appear in the blood.

In a biochemical analysis, blood acidification increases - metabolic acidosis, an enlargement of the thyroid gland occurs, and already a few days after poisoning, the level of hormones drops.

The harm of cobalt as a source of acute poisoning is also that they are not very indicative. All this leads to significant difficulties in diagnosis. After all, it is not always possible to detect ataxia, especially against the background of poor health and dizziness in a lying patient. Therefore, the most important thing should be an indication of the source of poisoning, or production history data.

Chronic intoxication

The symptoms of chronic cobalt poisoning are much more diverse. Patients often complain of cough and symptoms of bronchitis, disturbances of smell and loss of appetite. Chronic inflammatory diseases of the upper respiratory tract often occur; the appearance of pneumosclerosis can be seen on an x-ray.

A special type of lung damage is the so-called carbide occupational asthma (TSOA). It was first described and identified as a separate disease in 1967. It has been proven that the main cause of this asthma is the hard alloys of tungsten carbide and cobalt. At the same time, it was revealed that tungsten carbide is physiologically inert and cannot be a cause of asthma, so cobalt carbide is to blame.

Most often, asthma such as pulmonary allergy to cobalt is observed in grinders with extensive experience; it occurs with manifestations of chronic respiratory failure, attacks of suffocation and the development of pulmonary fibrosis.

Also, with chronic intoxication, patients experience chronic pneumonitis, with intense fibrosis, when the lung tissue involved in breathing is replaced by ballast fibrous tissue.

A long history of the disease leads to a chronic cough, a feeling of heaviness in the chest, shortness of breath increases, body weight decreases, and in combination with other lesions, the progression of such a disease can lead to death.

It is noted that such chronic lung disease is especially likely if the maximum permissible concentration of cobalt in the air of industrial premises is exceeded.

In severe chronic lesions, anemia and symptoms of liver damage occur; upon contact, cobalt compounds can cause various skin lesions. These are occupational dermatitis, the development of eczema. In some cases, cobalt-chrome alloy used in can also cause harm .

Allergy to cobalt in dentistry

As is known, more than 20 metals are used in orthopedic dentistry. The development of allergies is very much accompanied by electrochemical processes that occur in the oral cavity depending on the composition of the metal, temperature, and the chemical composition of saliva.

If cobalt or chromium is used in a dental alloy, this can cause symptoms of allergic stomatitis.

Often, dental crowns chromium and cobalt alloys cause allergies - in such patients, after combining with the proteins of the body's tissues, cobalt atoms begin to exhibit antigenic properties, although not expressed.

However, it is necessary to distinguish between a toxic reaction to the metal of the prosthesis and gradually developing allergic stomatitis. In the case of a toxic reaction, it develops very quickly, literally a day after orthopedic treatment. For correct diagnosis, it is necessary to determine whether there is a toxic dose of cobalt and other heavy metals in saliva, for which a spectrogram is performed, and it is also necessary to remove the denture and conduct an elimination test.

Also in dentistry, immunological tests are carried out, in which antibodies are determined not only to metals, but also to plastics. If the content of cobalt, manganese, chromium or nickel in saliva is increased, such dentures must be removed.

But, before installing prostheses containing heavy metals, it is necessary to identify the presence of allergies using skin tests.

In conclusion, it should be said that cobalt is harmful to the body , of course, exists, but in our time poisoning can only be caused by occupational diseases, since acute poisoning with cobalt and its salts has now become a clinical casuistry.

As an example, we can cite quite rare cases of children swallowing magnets that contain cobalt. Under the influence of gastric juice, its alloys turn into soluble salts and are absorbed in the form of chloride, which in children can lead to symptoms of serious poisoning.

Therefore, compliance with safety regulations at work can completely eliminate the possibility of intoxication.

Source: http://xlom.ru/professionalnye-zabolevaniya/kobalt-i-ego-toksichnost-vred-i-polza-kobalta/

Cobalt - 1. Chemical element, a silvery-white solid metal with a reddish tint, used in technology and medicine.
2. A mineral containing this metal.
3. Durable bright blue paint that contains this metal.

The meaning of the word Cobalt according to Ozhegov:

Cobalt - Chemical element, hard silvery-white metal with a reddish tint

Cobalt in the Encyclopedic Dictionary:

Cobalt - (lat. Cobaltum) - Co, chemical element of group VIII of the periodic system, atomic number 27, atomic mass 58.9332. The name is from the German Kobold - brownie, gnome. Silvery-white metal with a reddish tint. density 8.9 g/cm3, melting point 1494.C. ferromagnetic (Curie point 1121.C). Chemically resistant at normal temperatures in air.

The minerals are rare and are mined from nickel ores. Cobalt mainly used to produce cobalt alloys (magnetic, heat-resistant, super-hard, corrosion-resistant, etc.). The radioactive isotope 60Co is used as a source of ?-radiation in medicine and technology.

Cobalt is important for the life of plants and animals and is part of vitamin B12.

The meaning of the word Cobalt according to the dictionary of medical terms:

cobalt (Cobaltum. Co) is a chemical element of group VIII of the periodic table of D. I. Mendeleev, at. number 27, at. mass 58.9332. is a permanent component of living organisms (for example, it is part of cyanocobalamin) and is one of the most important microelements.

The meaning of the word Cobalt according to Ushakov’s dictionary:

COBALT , cobalt, pl. no, m. (German: Kobalt). 1. A chemical element with the properties of a metal (chemical). 2. Dark blue paint in powder form (schmalt) containing this metal (trade). 3. in meaning unchanged adj. Colors of this paint (colloquial, rare). Cobalt colored porcelain cup.

The meaning of the word Cobalt according to Dahl's dictionary:

Cobalt
is a greyish-colored metal found in various fossils, which, by appearance, are called: white cobalt, red cobalt, etc. Cobalt, containing cobalt, related to it. Cobalt flowers, red arsenic cobalt.

Definition of the word "Cobalt" according to TSB:

Cobalt (lat. Cobaltum)
Co, a chemical element of the first triad of group VIII of the Mendeleev periodic system.
atomic number 27, atomic mass 58.9332. heavy metal of silver color with a pinkish tint. In nature, the element is represented by one stable isotope 59Co. Of the artificially obtained radioactive isotopes, the most important is 60Co. Historical reference. Oxide K.

used in Ancient Egypt, Babylon, and China to color glass and enamels blue.
For the same purpose in the 16th century. In Western Europe, they began to use tsafra, or safflower, a gray earthy mass that was obtained by roasting certain ores called “kobold”. When roasted, these ores emitted abundant toxic smoke, and it was not possible to smelt metal from the product of their roasting.

Medieval miners and metallurgists considered this to be the work of mythical creatures - kobolds (from the German Kobold - brownie, gnome).
In 1735, the Swedish chemist G. Brandt, heating a mixture of tsafra with coal and flux in a forge with a blast, obtained a metal that he called “kobold king.” The name was soon changed to "cobolt" and then to "cobalt".
Distribution in nature. K. in the lithosphere 1.8·10&minus.3% by mass. In the earth's crust it migrates in magmas, hot and cold waters.

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During magmatic differentiation, calcium accumulates mainly in the upper mantle: its average content in ultrabasic rocks is 2·10&minus.2%.
The formation of so-called segregation deposits of cobalt ores is associated with magmatic processes.
Concentrating from hot underground waters, carbon dioxide forms hydrothermal deposits. in them Co is associated with Ni, As, S, Cu. About 30 cobalt minerals are known (see Cobalt ores). In the biosphere of K.

It is predominantly dispersed, but in areas where there are plants that are cobalt concentrators, cobalt deposits are formed.
In the upper part of the earth's crust, a sharp differentiation of carbon is observed—clays and shales contain, on average, 2·10&minus.3% carbon, sandstones contain 3·10&minus.5, and limestones contain 1·10&minus.5. Sandy soils in forest areas are the poorest. There is little carbon in surface waters; in the World Ocean it is only 5·10&minus.8%. Being a weak water migrant, K.

easily passes into sediments, being adsorbed by manganese hydroxides, clays and other highly dispersed minerals.
Physical and chemical properties. At ordinary temperatures and up to 417°C, the crystal lattice of crystals is hexagonal, close-packed (with periods a = 2.5017 E, c = 4.614 E), above this temperature the crystal lattice is face-centered cubic (a = 3.5370 E). Atomic radius 1.25 E, ionic radii Co2+0.78 E and Co3+0.64 E.

Density 8.9 g/cm3 (at 20°C): tnl 1493°Cо, boiling point 3100°C.
Heat capacity is 0.44 kJ/(kg K), or 0.1056 cal/(g °C). thermal conductivity 69.08 W/(m·K), or 165 cal/(cm·sec·°C) at 0-100°C. Electrical resistivity 5.68·10&minus.8 ohm·m, or 5.68·10&minus.6 ohm·cm (at 0°C). K. is ferromagnetic, and retains ferromagnetism from low temperatures to the Curie point, &Theta. = 1121 ° C (see Ferromagnetism). Mechanical properties of K.

depend on the method of mechanical and thermal treatment.
Tensile strength 500 MN/mI (or 50 kgf/mmI) for forged and annealed K.. 242-260 MN/mI for cast. 700 MN/mI for wire. Brinell hardness is 2.8 H/m² (or 280 kgf/mm²) for cold-worked metal, 3.0 H/m² for electrodeposited metal. 1.2-1.3 H/mI for annealed. Configuration of the outer electron shells of the K atom. 3d74sІ. In compounds, K. exhibits variable valency.

In simple compounds, Co (II) is most stable, in complex compounds - Co (III). Only a few complex compounds have been obtained for Co (I) and Co (IV). At ordinary temperatures, compact K. is resistant to the action of water and air. Finely crushed carbon, obtained by reducing its oxide with hydrogen at 250°C (pyrophoric carbon), spontaneously ignites in air, turning into CoO. Compact carbon begins to oxidize in air above 300°C.

at red heat it decomposes water vapor: Co + H2O = CoO + H2.
K easily combines with halogens when heated, forming CoX2 halides. When heated, chlorine interacts with S, Se, P, As, Sb, C, Si, B, and the composition of the resulting compounds sometimes does not satisfy the valence states indicated above (for example, Co2P, Co2As, CoSb2, Co3C, CoSi3). In dilute hydrochloric and sulfuric acids K.

slowly dissolves with the release of hydrogen and the formation of chloride CoCl2 and sulfate CoSO4, respectively. Dilute nitric acid dissolves nitrogen, releasing nitrogen oxides and forming nitrate Co (NO3)2. Concentrated HNO3 passivates metals (see Passivation of metals). The mentioned Co(II) salts are highly soluble in water [at 25°C, 100 g of water dissolves 52.4 g of CoCl2, 39.3 g of CoSO4, 136.4 g of Co (NO3)2].

Caustic alkalis precipitate blue hydroxide Co (OH)2 from solutions of Co2+ salts, which gradually turns brown due to oxidation by atmospheric oxygen to Co (OH)3.
Heating in oxygen at 400-500°C converts CoO into black oxide Co3O4, or CoO·Co2O3 - a Spinel-type compound. A compound of the same type, CoAl2O4 or CoAl2O3, blue in color (Thenar blue, discovered in 1804 by L. J. Thenar) is obtained by calcining a mixture of CoO and Al2O3 at a temperature of about 1000°C.

Of the simple Co(III) compounds, only a few are known. When fluorine acts on Co or CoCl2 powder at 300-400°C, brown fluoride CoF3 is formed. Co(III) complex compounds are very stable and easy to obtain. For example, KNO2 precipitates yellow, sparingly soluble potassium hexanitrocobaltate (III) K3[Co (NO2)6] from solutions of Co (II) salts containing CH3COOH.

Cobaltamines (formerly known as cobaltamines) are very numerous - complex compounds of Co (III) containing ammonia or some organic amines.
Receipt and application. K. minerals are rare and do not form significant ore accumulations. The main source of industrial production of nickel is nickel ores containing nickel as an impurity. Processing these ores is very complex, and the method depends on the composition of the ore. Ultimately, a solution of K chlorides is obtained.

and nickel containing impurities Cu2+, Pb2+, Bi3+.
The action of H2S precipitates the sulfides of Cu, Pb, Bi, after which Fe (II) is converted to Fe (lll) by passing chlorine and Fe (OH)3 and CaHAsO4 are precipitated by adding CaCO3. Nickel is separated from nickel by the reaction: 2CoCl2+NaCIO+4NaOH+H2O = 2Co (OH)3 &darr.+5NaCI. Almost all the nickel remains in solution. The black precipitate of Co(OH)3 is calcined to remove water. the resulting oxide Co3O4 is reduced with hydrogen or carbon. Metal K.

, containing up to 2-3% impurities (Ni, Fe, Cu, etc.), can be purified by electrolysis.
K. is used mainly in the form of alloys. These are cobalt alloys, as well as alloys based on other metals, where cobalt serves as an alloying element. Carbon alloys are used as heat-resistant and heat-resistant materials in the manufacture of permanent magnets, cutting tools, etc. Powdered carbon and Co3O4 serve as catalysts. Fluoride CoF3 is used as a strong fluorinating agent, thenar blue and especially K and potassium silicate (see Smalt) as paints in the ceramic and glass industries. K. salts are used in agriculture as microfertilizers, as well as for feeding animals.S. A. Pogodin.

Of the artificially radioactive isotopes of carbon, the most important is 60Co, with a half-life TS = 5.27 years, which is widely used as a gamma emitter. In technology it is used for gamma flaw detection. In medicine - mainly for radiation therapy of tumors (see Gamma installation) and for sterilization of medications.

It also serves to kill insects in grains and vegetables and to preserve food. Dr. radioactive isotopes - 56Co (TS = 77 days), 57Co (270 days) and 58Co (72 days) as less dangerous (short half-life) are used as isotope indicators in the study of metabolism, in particular to study the distribution of K.

in the body of animals (with the help of radioactive K. they studied the permeability of the placenta, etc.).

Source: https://xn----7sbbh7akdldfh0ai3n.xn--p1ai/kobalt.html

Cobalt and its characteristics

In nature, cobalt is not widespread: the content in the earth's crust is about 0.004% (mass.). Most often, cobalt is found in combination with arsenic in the form of the minerals cobalt speck CoAs2 and cobalt luster CoAs.

Cobalt is a hard, malleable, shiny metal similar to iron (Fig. 1). Like iron, it has magnetic properties. Water and air have no effect on it. It is much more difficult to dissolve in dilute acids than iron.

Rice. 1. Cobalt. Appearance.

Atomic and molecular mass of cobalt

The relative molecular mass of a substance (Mr) is a number showing how many times the mass of a given molecule is greater than 1/12 the mass of a carbon atom, and the relative atomic mass of an element (Ar) is how many times the average mass of atoms of a chemical element is greater than 1/12 the mass of an atom carbon.

Since in the free state cobalt exists in the form of monatomic Co molecules, the values of its atomic and molecular masses coincide. They are equal to 58.9332.

Allotropy and allotropic modifications of cobalt

Cobalt has two modifications. α-cobalt (hexagonal close-packed lattice) is stable up to 430oC; above 430oC - b-cobalt (face-centered cubic lattice).

Isotopes of cobalt

It is known that in nature cobalt can be found in the form of the only stable isotope 59Co. The mass number is 59, the nucleus of an atom contains twenty-seven protons and thirty-two neutrons.

There are artificial unstable isotopes of cobalt with mass numbers from 45 to 75 and eleven meta-stable states, among which the longest-lived is 60Co with a half-life of 5.2714 years.

Cobalt ions

The electronic formula demonstrating the distribution of cobalt electron orbitals is as follows:

1s22s22p63s23p63d74s2.

As a result of chemical interaction, cobalt gives up its valence electrons, i.e. is their donor, and turns into a positively charged ion:

Co 0 -2e → Co 2+;

Co 0 -3e → Co 3+;

Co 0 -4e → Co 4+.

Cobalt molecule and atom

In the free state, cobalt exists in the form of monoatomic Co molecules. Here are some properties characterizing the cobalt atom and molecule:

Atom ionization energy, eV	7,86
Relative electronegativity	1,88
Atomic radius, nm	0,116

Cobalt alloys

Cobalt is used mainly in alloys, which are used as heat-resistant and heat-resistant materials. The heat-resistant and heat-resistant Vitallium alloy contains 65% cobalt, 28% chromium, 3% tungsten and 4% molybdenum. This alloy retains high strength and does not corrode at temperatures up to 800-850oC.

Stellite hard alloys containing 40-60% cobalt, 20-35% chromium, 5-20% tungsten and 1-2% carbon are used for the manufacture of cutting tools. Cobalt is also included in the composition of ceramic-metallic hard alloys - cermets.

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Cobalt

COBALT, Co (from German Kobold - brownie, gnome * a. cobalt; n. Kobalt; f. cobalt; i. cobalto), is a chemical element of group VIII of the periodic system of Mendeleev, atomic number 27, atomic mass 58.9332. Natural cobalt consists of 2 stable isotopes 59Co (99.83%) and 57Co (0.17%). The most important of the artificial radioactive isotopes is 60Co. Obtained in 1735 by the Swedish chemist G. Brandt.

Characteristics of cobalt

Cobalt is a pale yellow metal with a pinkish or bluish tint. The crystal lattice below 430°C is hexagonal close-packed, above it is face-centered cubic.

Density 8900 kg/m3; melting point 1494°С; boiling point 2960°C; modulus of elasticity (19.6-20.6)•1010 Pa; temperature coefficient of linear expansion 12.08•10-6 K-1 at 0°C; Cp (temperature 20°C) 24.8 J/(mol•K); D Npl 0.277 MJ/kg; thermal conductivity coefficient l 69.08 W/(m•K) at 20°C; resistivity r=5.68•10-8 Ohm•m; work function 4.41 eV; ferromagnetic, Curie point 1121°C. Oxidation state +2 and +3. Compact cobalt is stable in air, above 300°C it is covered with a CoO film; finely dispersed cobalt is pyrophoric; reacts with dilute acids (except HF); at room temperature it interacts with halogens (except F2), when heated to 300-500°C - with S, P, As. Forms continuous series of solid solutions with Fe, Ir, Mn, Ni, Pd, Pt, Rh, organic solid solutions with Au, Cr, Os, Re, intermetallic compounds with many metals. Cobalt dust is toxic: MPC 0.5 mg/m3.

Cobalt in nature

Cobalt has been found in trace quantities in sea water, mineral springs, soil, plants and living organisms. For information on the main genetic types of deposits and enrichment methods, see Art. Cobalt ores. Associated extraction of cobalt is possible during the processing of cobalt-containing ores of iron ore magnetite deposits, enriched in the sulfide component; iron-manganese oceanic nodules.

Metallic cobalt is obtained by reduction smelting with coal, electrolysis of solutions of cobalt sulfate or chloride, reduction of hydroxides and ammonia solutions with hydrogen under pressure from ammonia solutions - products of hydrometallurgical or combined (pyro- and hydrometallurgical) processing of ores.

Cobalt is separated from accompanying metals by fractional oxidation and hydrolytic precipitation, as well as extraction.

Application and Use

Cobalt is used mainly in the production of heat-resistant, magnetic, super-hard, corrosion-resistant and other alloys and coatings. Catalysts for organic synthesis are made based on cobalt. The radioactive isotope 60Co (TS, 5.24 years) is a source of g-radiation in technology and medicine (“cobalt gun”). Cobalt compounds are used in the production of durable enamels and paints, ceramics and glass, and in the production of chemicals.

Source: http://www.mining-enc.ru/k/kobalt/

Cobalt | Application

The main share of the resulting cobalt is spent on the preparation of various alloys; cobalt, like tungsten, is indispensable in metalworking - it serves as the most important component of tool high-speed steels. Tungsten or titanium carbide, the main component of the hard alloy, is sintered in a mixture with cobalt metal powder. Cobalt connects the grains of carbides and gives the entire alloy greater viscosity, reducing its sensitivity to shocks and impacts.

Magnetic properties

And one more important property: if tungsten steel loses its magnetic properties by almost a third under the influence of vibrations, then cobalt steel loses by only 23.5%.

Magnetic alloys based on cobalt are used in the manufacture of electric motor cores, they are used in transformers and other electrical devices. Cobalt soft magnetic alloys are used to manufacture magnetic recording heads.

Cobalt hard magnetic alloys such as SmCo5, PrCo5, etc., characterized by high magnetic energy, are used in modern instrument making.

For the manufacture of permanent magnets, alloys containing 52% cobalt and 5-14% vanadium or chromium (the so-called vicalloys) are used.

Catalysts

Cobalt and some of its compounds serve as catalysts. Cobalt compounds introduced into glass during melting provide a beautiful blue (cobalt) color to glass products. Cobalt compounds are used as pigments for many dyes. Lithium cobaltate is used as a highly efficient positive electrode for the production of lithium batteries. Cobalt silicide is an excellent thermoelectric material and allows the production of thermoelectric generators with high efficiency.

Radiological effect

Cobalt is used in medicine to treat malignant tumors with radioactive radiation. Now all over the world, the radioactive isotope of cobalt - 60Co, which produces the most uniform radiation, is used to irradiate cancer-affected tissues (in cases where such treatment is generally possible).

Source: https://www.allmetals.ru/metals/cobalt/apply/

The meaning of the word "Cobalt"

meaning of the word:

m. metal of a grayish color, in various fossils, which, by appearance, are called: white cobalt, red, etc. Cobalt, containing cobalt, related to it. Cobalt flowers, red arsenic cobalt.

In Ozhegov's dictionary

COBALT, -a, m. Chemical element, hard silvery-white metal with a reddish tint. || adj. cobalt, -aya, -oh. K. alloy.

In the dictionary Dr. Ushakova

COBALT, cobalt, pl.
no, husband (·German: Kobalt). 1. A chemical element with the properties of a metal (chemical).
2. Dark blue paint in powder form (schmalt) containing this metal (trade).
3. in meaning unism. adj. The colors of this paint (colloquial, rare). Cobalt colored porcelain cup.

In the encyclopedia dictionary

(lat. Cobaltum), Co, chemical element of group VIII of the periodic system, atomic number 27, atomic mass 58.9332. The name comes from the German Kobold - brownie, gnome. Silvery-white metal with a reddish tint; density 8.9 g/cm3, melting point 1494 °C; ferromagnetic (Curie point 1121 °C). At normal temperatures in air it is chemically resistant.

The minerals are rare and are extracted from nickel ores. Cobalt is mainly used to produce cobalt alloys (magnetic, heat-resistant, super-hard, corrosion-resistant, etc.). The radioactive isotope 60Co is used as a source of ?-radiation in medicine and technology. Cobalt is important for the life of plants and animals and is part of vitamin B12.

In the dictionary of medical terms

(Cobaltum; Co) chemical element of group VIII of the periodic system of D. I. Mendeleev, at. number 27, at. mass 58.9332; is a permanent component of living organisms (for example, it is part of cyanocobalamin) and is one of the most important microelements.

There are 4 synonyms in the dictionary

cobaltine, paint, metal, element

The dictionary contains a complete accented paradigm according to a. A. slug

cobalt, cobalts, cobalt, cobalts, cobalt, cobalts, cobalt, cobalts, cobalt, cobalts, cobalt, cobalts

Source: https://glosum.ru/%D0%97%D0%BD%D0%B0%D1%87%D0%B5%D0%BD%D0%B8%D0%B5-%D1%81%D0% BB%D0%BE%D0%B2%D0%B0-%D0%9A%D0%BE%D0%B1%D0%B0%D0%BB%D1%8C%D1%82