The serial number of copper in the periodic table. Methods for obtaining copper

Copper is a malleable golden-pink metal with a characteristic metallic sheen. In the periodic system of D. I. Mendeleev, this chemical element is designated as Сu (Cuprum) and is under serial number 29 in group I (side subgroup), in period 4.

The Latin name Cuprum comes from the name of the island of Cyprus. There are known facts that in the 3rd century BC there were copper mines in Cyprus and local craftsmen smelted copper. You can buy copper in the company « ».

According to historians, the acquaintance of society with copper is about nine thousand years old. The most ancient copper products were found during archaeological excavations in the area of modern Turkey. Archaeologists have found small copper beads and plates to decorate clothes. The finds date back to the 8th-7th millennium BC. In ancient times, jewelry, expensive dishes and various tools with a thin blade were made from copper.

The great achievement of the ancient metallurgists can be called the production of an alloy with a copper base - bronze.

Basic properties of copper

1. Physical properties.

In air, copper acquires a bright yellowish-red hue due to the formation of an oxide film. Thin plates are greenish-blue when translucent. In its pure form, copper is quite soft, ductile and easily rolled and drawn. Impurities can increase its hardness.

The high electrical conductivity of copper can be called the main property that determines its predominant use. Copper also has a very high thermal conductivity. Impurities such as iron, phosphorus, tin, antimony and arsenic affect the basic properties and reduce electrical and thermal conductivity. According to these indicators, copper is second only to silver.

Copper has high density, melting point and boiling point. Good corrosion resistance is also an important property. For example, at high humidity, iron oxidizes much faster.

Copper lends itself well to processing: it is rolled into a copper sheet and a copper bar, stretched into a copper wire with a thickness brought to thousandths of a millimeter. This metal is diamagnetic, that is, it is magnetized against the direction of an external magnetic field.

Copper is a relatively inactive metal. Under normal conditions, in dry air, its oxidation does not occur. It easily reacts with halogens, selenium and sulfur. Acids without oxidizing properties do not affect copper. There are no chemical reactions with hydrogen, carbon and nitrogen. In moist air, oxidation occurs with the formation of copper carbonate (II) - the upper layer of platinum.
Copper is amphoteric, that is, it forms cations and anions in the earth's crust. Depending on the conditions, copper compounds exhibit acidic or basic properties.

Methods for obtaining copper

In nature, copper exists in compounds and in the form of nuggets. The compounds are represented by oxides, bicarbonates, sulfur and carbon dioxide complexes, as well as sulfide ores. The most common ores are copper pyrite and copper sheen. The copper content in them is 1-2%. 90% of primary copper is mined by pyrometallurgical methods and 10% by hydrometallurgical methods.

1. The pyrometallurgical method includes the following processes: beneficiation and roasting, melting to matte, blowing in the converter, electrolytic refining.
Copper ores are enriched by flotation and oxidative roasting. The essence of the flotation method is as follows: copper particles suspended in an aqueous medium adhere to the surface of air bubbles and rise to the surface. The method allows to obtain a copper powder concentrate, which contains 10-35% copper.

Copper ores and concentrates with a significant sulfur content are subject to oxidative roasting. When heated in the presence of oxygen, sulfides are oxidized, and the amount of sulfur is almost halved. Poor concentrates, which contain 8-25% copper, are subjected to roasting. Rich concentrates containing 25-35% copper are melted without firing.

The next step in the pyrometallurgical method for producing copper is matte smelting. If lump copper ore with a large amount of sulfur is used as raw material, then smelting is carried out in shaft furnaces. And for powdered flotation concentrate, reverberatory furnaces are used. Melting takes place at a temperature of 1450 °C.

In side-blown horizontal converters, the copper matte is blown with compressed air in order to oxidize the sulfides and ferrum. Next, the resulting oxides are converted into slag, and sulfur into oxide. Blister copper is formed in the converter, which contains 98.4-99.4% copper, iron, sulfur, as well as a small amount of nickel, tin, silver and gold.

Blister copper is subject to fire and then electrolytic refining. Impurities are removed with gases and transferred to slag. As a result of fire refining, copper with a purity of up to 99.5% is formed. And after electrolytic refining, the purity is 99.95%.

2. The hydrometallurgical method consists in leaching copper with a weak solution of sulfuric acid, and then separating metallic copper directly from the solution. This method is used for the processing of poor ores and does not allow the associated extraction of precious metals along with copper.

The use of copper

Due to their valuable qualities, copper and copper alloys are used in the electrical and electrical engineering industries, in radio electronics and instrument making. There are alloys of copper with metals such as zinc, tin, aluminum, nickel, titanium, silver, gold. Rarely used alloys with non-metals: phosphorus, sulfur, oxygen. There are two groups of copper alloys: brass (alloys with zinc) and bronze (alloys with other elements).

Copper has a high environmental friendliness, which allows its use in the construction of residential buildings. For example, a copper roof due to its anti-corrosion properties can last more than a hundred years without special care and painting.

Copper alloyed with gold is used in jewelry. This alloy increases the strength of the product, increases the resistance to deformation and abrasion.

Copper compounds are characterized by high biological activity. In plants, copper is involved in the synthesis of chlorophyll. Therefore, it can be seen in the composition of mineral fertilizers. A lack of copper in the human body can cause a deterioration in the composition of the blood. It is found in many food products. For example, this metal is found in milk. However, it is important to remember that an excess of copper compounds can cause poisoning. That is why you can not cook food in copper utensils. During boiling, a large amount of copper can get into food. If the dishes inside are covered with a layer of tin, then there is no danger of poisoning.

In medicine, copper is used as an antiseptic and astringent. It is a component of eye drops for conjunctivitis and solutions for burns.

Copper(lat. Cuprum), Cu, a chemical element of Group I of Mendeleev's Periodic Table; atomic number 29, atomic mass 63.546; soft, malleable red metal. Natural M. consists of a mixture of two stable isotopes - 63 Cu (69.1%) and 65 Cu (30.9%).

History reference. M. belongs to the number of metals known from ancient times. The early acquaintance of a person with M. was facilitated by the fact that it occurs in nature in a free state in the form of nuggets (see. Native copper), which sometimes reach considerable sizes. Metal and its alloys played an important role in the development of material culture (see Bronze Age). Owing to the easy reducibility of oxides and carbonates, metal was apparently the first metal that man learned to recover from the oxygen compounds contained in ores. The Latin name M. comes from the name of the island of Cyprus, where the ancient Greeks mined copper ore. In ancient times, to process rock, it was heated on a fire and quickly cooled, and the rock cracked. Already under these conditions, recovery processes were possible. Subsequently, restoration was carried out in fires with a large amount of coal and with air blowing through pipes and bellows. Bonfires were surrounded by walls that gradually rose, which led to the creation of a shaft furnace. Later, reduction methods gave way to oxidative smelting of sulfide copper ores to produce intermediate products—matte (an alloy of sulfides), in which metal is concentrated, and slag (an alloy of oxides).

distribution in nature. The average content of M. in the earth's crust (clarke) is 4.7 10 -3% (by mass), in the lower part of the earth's crust, composed of basic rocks, it is more (1 10 -2%) than in the upper (2 ). 10 -3%), where granites and other acidic igneous rocks predominate. M. migrates vigorously both in the hot waters of the depths and in the cold solutions of the biosphere; Hydrogen sulfide precipitates various mineral sulfides from natural waters, which are of great industrial importance. Sulfides, phosphates, sulphates, and chlorides predominate among the numerous mineral minerals; native mineral, carbonates, and oxides are also known.

M. is an important element of life; it participates in many physiological processes. The average content of M. in living matter is 2 10 -4%, organisms are known to be M. concentrators. In taiga and other landscapes of a humid climate, M. is relatively easily leached from acidic soils, here in places there is a deficiency of M. and related diseases of plants and animals. (especially on sands and peatlands). In the steppes and deserts (with slightly alkaline solutions characteristic of them), M. is inactive; in areas of M. deposits, its excess is observed in soils and plants, which makes domestic animals sick.

There is very little M. in river water, 1 10 -7%. M. brought into the ocean with a runoff passes relatively quickly into sea silts. Therefore, clays and shales are somewhat enriched with mineral (5.7 10 -3%), and sea water is sharply undersaturated with mineral (3 10 -7%).

In the seas of past geological epochs, in places there was a significant accumulation of mineral deposits in silts, which led to the formation of deposits (for example, Mansfeld in the GDR). M. also migrates vigorously in the underground waters of the biosphere, and the accumulation of M.'s ores in sandstones is associated with these processes.

Physical and chemical properties. The color of M. is red, pink in the break, greenish-blue when translucent in thin layers. The metal has a face-centered cubic lattice with the parameter a= 3.6074; density 8.96 g/cm 3(20°C). Atomic radius 1.28; ionic radii Cu + 0.98; Cu 2+ 0.80; t sq. 1083°C; t bale 2600°C; specific heat capacity (at 20 °C) 385.48 j/(kg K), i.e. 0.092 feces/(G·°C). The most important and widely used properties of M.: high thermal conductivity - at 20 °C 394.279 Tue/(m K), i.e. 0.941 feces/(cm sec°C); low electrical resistance - at 20 °C 1.68 10 -8 ohm m. Thermal coefficient of linear expansion 17.0·10 -6 . The vapor pressure over M. is negligible, the pressure is 133.322 n / m 2(i.e. 1 mmHg Art.) is achieved only at 1628 °C. M. is diamagnetic; atomic magnetic susceptibility 5.27·10 -6 . Hardness M. according to Brinell 350 MN/m 2(i.e. 35 kgf/mm 2); tensile strength 220 MN/m 2(i.e. 22 kgf/mm 2); elongation 60%, modulus of elasticity 132 10 3 MN/m 2(i.e. 13.2 10 3 kgf/mm 2). By working hardening, the tensile strength can be increased to 400-450 MN/m 2, while the elongation decreases to 2%, and the electrical conductivity decreases by 1-3%. Annealing of hardened metal should be carried out at 600–700 °C. Small impurities of Bi (thousandths of a%) and Pb (hundredths of a%) make M. red-brittle, and the admixture of S causes brittleness in the cold.

On chemical properties M. occupies an intermediate position between elements of the first triad of the VIII group and alkaline elements of the I group of Mendeleev's system. M., like Fe, Co, Ni, is prone to complex formation, gives colored compounds, insoluble sulfides, etc. The similarity with alkali metals is insignificant. So, M. forms a number of monovalent compounds, however, the 2-valent state is more characteristic of it. Salts of monovalent M. are practically insoluble in water and are easily oxidized to compounds of 2-valent M.; salts of 2-valent M., on the contrary, are well soluble in water and are completely dissociated in dilute solutions. Hydrated Cu 2+ ions are colored blue. There are also compounds in which M. is 3-valent. So, by the action of sodium peroxide on a solution of sodium cuprite Na 2 CuO 2, oxide Cu 2 O 3 was obtained - a red powder, which begins to give oxygen already at 100 ° C. Cu 2 O 3 is a strong oxidizing agent (for example, it releases chlorine from hydrochloric acid).

The chemical activity of M. is small. Compact metal at temperatures below 185 ° C does not interact with dry air and oxygen. In the presence of moisture and CO 2, a green film of basic carbonate forms on the surface of the mineral. When heated in air, surface oxidation occurs; below 375 °C, CuO is formed, and in the range of 375-1100 °C, with incomplete oxidation of M., a two-layer scale is formed, in the surface layer of which CuO is located, and in the inner layer - Cu 2 O (see Fig. Copper oxides). Wet chlorine interacts with M. already at ordinary temperatures, forming chloride CuCl 2, which is highly soluble in water. M. easily combines with other halogens (see. Copper halides). M. has a special affinity for sulfur and selenium; so, it burns in sulfur vapor (see. Copper sulfides). M. does not react with hydrogen, nitrogen, and carbon even at high temperatures. The solubility of hydrogen in solid sodium is negligible and at 400 °C is 0.06 mg at 100 G M. Hydrogen and other combustible gases (CO, CH 4), acting at high temperature on M. ingots containing Cu 2 O, reduce it to metal with the formation of CO 2 and water vapor. These products, being insoluble in M., stand out from it, causing the appearance of cracks, which sharply worsens the mechanical properties of M.

When NH 3 is passed over a red-hot M., Cu 3 N is formed. Already at a heating temperature, M. is exposed to nitrogen oxides, namely NO, N 2 O (with the formation of Cu 2 O) and NO 2 (with the formation of CuO). Carbides Cu 2 C 2 and CuC 2 can be obtained by the action of acetylene on ammonia solutions of M salts. The normal electrode potential of M. for the reaction Cu 2+ + 2e Сu is +0.337 in, and for the reaction Cu + + e Cu is +0.52 in. Therefore, M. is displaced from its salts by more electronegative elements (iron is used in industry) and does not dissolve in non-oxidizing acids. M. dissolves in nitric acid with the formation of Cu (NO 3) 2 and nitrogen oxides, in a hot concentration of H 2 SO 4 - with the formation of CuSO 4 and SO 2, in heated dilute H 2 SO 4 - when blowing through an air solution. All M. salts are poisonous (see. Copper carbonates, copper nitrate, copper sulfate).

M. in the bi- and monovalent state forms numerous very stable complex compounds. Examples of complex compounds of monovalent M.: (NH 4) 2 CuBr 3; K 3 Cu(CN) 4 - double salt complexes; [Сu (SC (NH 2)) 2 ] CI and others. Examples of complex compounds of 2-valent M.: CsCuCI 3 , K 2 CuCl 4 - type of double salts. Of great industrial importance are ammonia complex compounds M.: [Cu (NH 3) 4 ] SO 4, [Cu (NH 3) 2 ] SO 4 .

Receipt. Copper ores are characterized by a low content of M. Therefore, before smelting, finely divided ore is subjected to mechanical enrichment; at the same time, valuable minerals are separated from the bulk of the waste rock; as a result, a number of commercial concentrates (for example, copper, zinc, pyrite) and final tailings are obtained.

In world practice, 80% of M. is extracted from concentrates by pyrometallurgical methods based on the melting of the entire mass of the material. In the process of smelting, due to the greater affinity of mineral for sulfur, and the components of gangue and iron for oxygen, mineral is concentrated in a sulfide melt (matte), and oxides form slag. The matte is separated from the slag by settling.

In most modern factories, melting is carried out in reverberatory or electric furnaces. In reverberatory furnaces, the working space is extended in a horizontal direction; hearth area 300 m 2 and more (30 m ten m), the heat necessary for melting is obtained by burning carbonaceous fuel (natural gas, fuel oil, pulverized coal) in the gas space above the bath surface. In electric furnaces, heat is obtained by passing an electric current through the molten slag (the current is supplied to the slag through graphite electrodes immersed in it).

However, both reflective and electric melting, based on external sources of heat, are imperfect processes. Sulfides, which make up the bulk of copper concentrates, have a high calorific value. Therefore, more and more smelting methods are being introduced that use the heat of combustion of sulfides (the oxidizer is heated air, oxygen-enriched air, or technical oxygen). Fine, pre-dried sulfide concentrates are blown with a jet of oxygen or air into a furnace heated to a high temperature. Particles burn in a suspended state (oxygen suspended melting). Sulfides can also be oxidized in the liquid state; these processes are intensively studied in the USSR and abroad (Japan, Australia, Canada) and become the main direction in the development of pyrometallurgy of sulfide copper ores.

Rich lumpy sulfide ores (2-3% Cu) with a high sulfur content (35-42% S) in some cases are directly sent for smelting in shaft furnaces (furnaces with a vertically located working space). In one of the varieties of shaft smelting (copper-sulphur smelting), fine coke is added to the charge, which reduces SO 2 in the upper horizons of the furnace to elemental sulfur. Copper is also concentrated in the matte in this process.

The liquid matte obtained during smelting (mainly Cu 2 S, FeS) is poured into a converter - a cylindrical tank made of sheet steel, lined with magnesite bricks from the inside, equipped with a side row of lances for blowing air and a device for turning around the axis. Compressed air is blown through the matte layer. The matte conversion proceeds in two stages. First, iron sulfide is oxidized, and quartz is added to the converter to bind the iron oxides; converter slag is formed. Then copper sulfide is oxidized with the formation of metal M. and SO 2 . This draft M. is poured into molds. Ingots (and sometimes directly molten crude metal) are sent for fire refining to extract valuable satellites (Au, Ag, Se, Fe, Bi, and others) and remove harmful impurities. It is based on the greater affinity of impurity metals for oxygen than that of copper: Fe, Zn, Co and partially Ni and others in the form of oxides pass into slag, and sulfur (in the form of SO 2) is removed with gases. After the slag is removed, metal is “teased” to restore the Cu 2 O dissolved in it by immersing the ends of raw birch or pine logs in liquid metal, after which it is cast into flat molds. For electrolytic refining, these ingots are suspended in a bath of CuSO 4 solution acidified with H 2 SO 4 . They serve as anodes. When a current is passed, the anodes dissolve, and pure M. is deposited on cathodes—thin copper sheets, also obtained by electrolysis in special matrix baths. Surface-active additives (carpenter's glue, thiourea, and others) are introduced into the electrolyte to isolate dense, smooth precipitates. The resulting cathodic mineral is washed with water and remelted. Noble metals, Se, Te, and other valuable minerals are concentrated in the anode sludge, from which they are extracted by special processing. Nickel concentrated in the electrolyte; by removing part of the solutions for evaporation and crystallization, it is possible to obtain Ni in the form of nickel vitriol.

Along with pyrometallurgical methods, hydrometallurgical methods are also used to obtain minerals (mainly from poor oxidized and native ores). These methods are based on the selective dissolution of copper-bearing minerals, usually in weak solutions of H 2 SO 4 or ammonia. M.'s solution is either precipitated with iron or isolated by electrolysis with insoluble anodes. Very promising for mixed ores are combined hydroflotation methods, in which the oxygen compounds of minerals are dissolved in sulfuric acid solutions, and sulfides are isolated by flotation. Autoclave hydrometallurgical processes proceeding at elevated temperatures and pressures are also gaining ground.

Application. The great role of magnetism in technology is due to a number of its valuable properties, primarily its high electrical conductivity, plasticity, and thermal conductivity. Thanks to these properties, M. is the main material for wires; over 50% of the mined mineral is used in the electrical industry. All impurities reduce the electrical conductivity of M., and therefore, in electrical engineering, high-grade metal containing at least 99.9% Cu is used. High thermal conductivity and corrosion resistance make it possible to manufacture critical parts of heat exchangers, refrigerators, vacuum apparatuses, etc. from M. About 30-40% M. is used in the form of various alloys, among which the most important are brass(from 0 to 50% Zn) and various types bronze; tin, aluminum, lead, beryllium, etc. (for details, see copper alloys). In addition to the needs of heavy industry, communications, and transport, a certain amount of mineral oil (mainly in the form of salts) is consumed for the preparation of mineral pigments, control of pests and plant diseases, as microfertilizers, catalysts for oxidative processes, as well as in the leather and fur industries and in production of artificial silk.

L. V. Vanyukov.

Copper as an art material is used with copper age(decorations, sculpture, utensils, dishes). Forged and cast products from metal and alloys (see. Bronze) are decorated with embossing, engraving and embossing. The ease of processing marble (due to its softness) allows craftsmen to achieve a variety of textures, thoroughness in working out details, and fine modeling of form. Products from M. are distinguished by the beauty of golden or reddish tones, as well as the property of gaining shine when polished. M. is often gilded, patinated (see. Patina), tinted, decorated with enamel. Since the 15th century, M. has also been used for the manufacture of printing plates (see. Engraving).

Copper in the body. M. - necessary for plants and animals trace element. M.'s main biochemical function is participation in enzymatic reactions as an activator or as part of copper-containing enzymes. The amount of M. in plants ranges from 0.0001 to 0.05% (per dry matter) and depends on the type of plant and the content of M. in the soil. In plants M. is a part of enzymes oxidases and plastocyanin protein. In optimal concentrations, M. increases the cold resistance of plants, promotes their growth and development. Among animals, the richest in M. are some invertebrates (in mollusks and crustaceans in hemocyanin contains 0.15-0.26% M.). Acting with food, M. is absorbed in the intestine, binds to the blood serum protein - albumin, then is absorbed by the liver, from where it returns to the blood as part of the ceruloplasmin protein and is delivered to organs and tissues.

The content of M. in humans fluctuates (by 100 G dry weight) from 5 mg in the liver up to 0.7 mg in bones, in body fluids - from 100 mcg(per 100 ml) in the blood up to 10 mcg in the cerebrospinal fluid; total M. in the body of an adult is about 100 mg. M. is part of a number of enzymes (for example, tyrosinase, cytochrome oxidase), stimulates the hematopoietic function of the bone marrow. Small doses of M. affect the metabolism of carbohydrates (decrease in blood sugar), minerals (decrease in the amount of phosphorus in the blood), etc. An increase in the content of M. in the blood leads to the conversion of mineral iron compounds into organic ones, stimulates the use of iron accumulated in the liver during synthesis hemoglobin.

With a lack of M., cereal plants are affected by the so-called processing disease, fruit plants - by exanthema; in animals, the absorption and use of iron is reduced, which leads to anemia accompanied by diarrhea and emaciation. Copper microfertilizers and feeding of animals with M. salts are used (see. Microfertilizers). Poisoning M. leads to anemia, liver disease, Wilson's disease. In humans, poisoning rarely occurs due to the subtle mechanisms of absorption and excretion of M. However, in large doses, M. causes vomiting; when M. is absorbed, general poisoning can occur (diarrhea, weakening of breathing and cardiac activity, suffocation, coma).

I. F. Gribovskaya.

In medicine, M. sulfate is used as an antiseptic and astringent in the form of eye drops for conjunctivitis and eye pencils for the treatment of trachoma. M. sulfate solution is also used for skin burns with phosphorus. Sometimes sulfate M. is used as an emetic. M. nitrate is used as an eye ointment for trachoma and conjunctivitis.

Lit.: Smirnov V.I., Metallurgy of copper and nickel, Sverdlovsk - M., 1950; Avetisyan H. K., Blister copper metallurgy, M., 1954; Gazaryan L. M., Pyrometallurgy of copper, M., 1960; Metallurgist's reference book on non-ferrous metals, edited by N. N. Murach, 2nd ed., vol. 1, M., 1953, vol. 2, M., 1947; Levinson N. P., [Products from non-ferrous and ferrous metal], in the book: Russian decorative art, vol. 1-3, M., 1962-65; Hadaway W. S., Illustrations of metal work in brass and copper mostly South Indian, Madras, 1913; Wainwright G. A., The occurrence of tin and copper near bybios, "Journal of Egyptian archeology", 1934, v. 20, pt 1, p. 29-32; BergsÆe P., The gilding process and the metallurgy of copper and lead among the precolumbian Indians, Kbh., 1938; Frieden E., The role of copper compounds in nature, in the book: Horizons of Biochemistry, translated from English, M., 1964; his own. Biochemistry of copper, in the book: Molecules and cells, translated from English, in. 4, M., 1969; Biological role of copper, M., 1970.

Copper- an element of a side subgroup of the first group, the fourth period of the periodic system of chemical elements of D. I. Mendeleev, with atomic number 29. It is designated by the symbol Cu (lat. Cuprum).

Copper is found in nature both in compounds and in native form. Of industrial importance are chalcopyrite CuFeS2, also known as copper pyrites, chalcocite Cu2S and bornite Cu5FeS4. Other copper minerals are found together with them: covelline CuS, cuprite Cu2O, azurite Cu3(CO3)2(OH)2, malachite Cu2CO3(OH)2. Sometimes copper is found in native form, the mass of individual accumulations can reach 400 tons. Copper sulfides are formed mainly in medium-temperature hydrothermal veins. Copper deposits are also often found in sedimentary rocks - cuprous sandstones and shales. The most famous deposits of this type are Udokan in the Chita region, Dzhezkazgan in Kazakhstan, the copper belt of Central Africa and Mansfeld in Germany.

Most of the copper ore is mined by open pit mining. The copper content in the ore ranges from 0.4 to 1.0%. Physical properties of copper

Copper is a golden-pink ductile metal, quickly covered with an oxide film in air, which gives it a characteristic intense yellowish-red tint. Copper has a high thermal and electrical conductivity (ranks second in electrical conductivity after silver). It has two stable isotopes - 63Cu and 65Cu, and several radioactive isotopes. The longest-lived of these, 64Cu, has a half-life of 12.7 hours and two decays with different products.

The color of Copper is red, pink in fracture, greenish-blue when translucent in thin layers. The metal has a face-centered cubic lattice with a = 3.6074 Å; density 8.96 g/cm3 (20 °C). Atomic radius 1.28 Å; ionic radii Cu+ 0.98 Å; Cu2+ 0.80 Å; tmelt 1083 °C; tbp 2600 °С; specific heat capacity (at 20 °C) 385.48 J/(kg K), i.e. 0.092 cal/(g °C). The most important and widely used properties of Copper are: high thermal conductivity - at 20 °C 394.279 W/(m·K.), i.e. 0.941 cal/(cm·sec·°С); low electrical resistance - at 20 °C 1.68 10-8 ohm m. Thermal coefficient of linear expansion 17.0 10-6. The vapor pressure over Copper is negligible, a pressure of 133.322 N/m2 (ie 1 mm Hg) is only reached at 1628°C. Copper is diamagnetic; atomic magnetic susceptibility 5.27 10-6. Brinell Copper hardness 350 MN/m2 (i.e. 35 kgf/mm2); tensile strength 220 MN/m2 (i.e. 22 kgf/mm2); elongation 60%, modulus of elasticity 132 103 MN/m2 (i.e. 13.2 103 kgf/mm2). By working hardening, the tensile strength can be increased to 400-450 MN/m2, while the elongation is reduced to 2%, and the electrical conductivity is reduced by 1-3.

Copper(Latin cuprum), cu, a chemical element of group I of Mendeleev's periodic system; atomic number 29, atomic mass 63.546; soft, malleable red metal. Natural M. consists of a mixture of two stable isotopes - 63 cu (69.1%) and 65 cu (30.9%).

History reference. M. belongs to the number of metals known from ancient times. The early acquaintance of a person with M. was facilitated by the fact that it occurs in nature in a free state in the form of nuggets, which sometimes reach significant sizes. Metal and its alloys played an important role in the development of material culture. Owing to the easy reducibility of oxides and carbonates, metal was apparently the first metal that man learned to recover from the oxygen compounds contained in ores. The Latin name M. comes from the name of the island of Cyprus, where the ancient Greeks mined copper ore. In ancient times, to process rock, it was heated on a fire and quickly cooled, and the rock cracked. Already under these conditions, recovery processes were possible. Subsequently, restoration was carried out in fires with a large amount of coal and with air blowing through pipes and bellows. Bonfires were surrounded by walls that gradually rose, which led to the creation of a shaft furnace. Later, reduction methods gave way to oxidative smelting of sulfide copper ores to produce intermediate products—matte (an alloy of sulfides), in which metal is concentrated, and slag (an alloy of oxides).

distribution in nature. The average content of M. in the earth's crust (clarke) is 4.7 10 -3% (by mass), in the lower part of the earth's crust, composed of basic rocks, it is more (1 10 -2%) than in the upper (2 10 -3%), where granites and other acidic igneous rocks predominate. M. migrates vigorously both in the hot waters of the depths and in the cold solutions of the biosphere; Hydrogen sulfide precipitates various mineral sulfides from natural waters, which are of great industrial importance. Sulfides, phosphates, sulphates, and chlorides predominate among the numerous mineral minerals; native mineral, carbonates, and oxides are also known.

M. is an important element of life; it participates in many physiological processes. The average content of M. in living matter is 2 10 -4%, organisms are known to concentrate M. In taiga and other landscapes of a humid climate, M. is relatively easily leached from acidic soils, here in places there is a deficiency of M. and related diseases of plants and animals. (especially on sands and peatlands). In the steppes and deserts (with slightly alkaline solutions characteristic of them), M. is inactive; in areas of M. deposits, its excess is observed in soils and plants, which makes domestic animals sick.

There is very little M. in river water, 1 × 10 -7%. M. brought into the ocean with a runoff passes relatively quickly into sea silts. Therefore, clays and shales are somewhat enriched with mineral (5.7 × 10 -3%), while sea water is sharply undersaturated with mineral (3 × 10 -7%).

Physical and chemical properties. The color of M. is red, pink in the break, greenish-blue when translucent in thin layers. The metal has a face-centered cubic lattice with the parameter a= 3.6074 å; density 8.96 g/cm 3(20 °C). Atomic radius 1.28 å; ionic radii cu + 0.98 å; cu 2+ 0.80 å; t sq. 1083 °С; t bale 2600 °С; specific heat capacity (at 20 °C) 385.48 j/(kg K) , i.e. 0.092 feces/(G ·°C). The most important and widely used properties of M.: high thermal conductivity - at 20 ° C 394.279 Tue/(m K) , i.e. 0.941 feces/(cm sec°С); low electrical resistance - at 20 ° C 1.68 10 -8 ohm m. Thermal coefficient of linear expansion 17.0 · 10 -6 . The vapor pressure over M. is negligible, the pressure is 133.322 n / m 2(i.e. 1 mmHg Art.) is achieved only at 1628 °C. M. is diamagnetic; atomic magnetic susceptibility 5.27 10 -6 . Hardness M. according to Brinell 350 MN/m 2(i.e. 35 kgf/mm 2); tensile strength 220 MN/m 2(i.e. 22 kgf/mm 2); relative elongation 60%, modulus of elasticity 132 10 3 MN/m 2(i.e. 13.2 10 3 kgf/mm 2). By working hardening, the tensile strength can be increased to 400-450 MN/m 2, while the elongation decreases to 2%, and the electrical conductivity decreases by 1-3%. Annealing of hardened metal should be carried out at 600–700 °C. Small impurities bi (thousandths of a%) and pb (hundredths of a%) make M. red-brittle, and an admixture of s causes brittleness in the cold.

According to its chemical properties, M. occupies an intermediate position between the elements of the first triad of group viii and the alkaline elements of group i of the Mendeleev system. M., like fe, Co, ni, is prone to complex formation, gives colored compounds, insoluble sulfides, etc. The similarity with alkali metals is insignificant. So, M. forms a number of monovalent compounds, however, the 2-valent state is more characteristic of it. Salts of monovalent M. are practically insoluble in water and are easily oxidized to compounds of 2-valent M.; salts of 2-valent M., on the contrary, are well soluble in water and are completely dissociated in dilute solutions. Hydrated ions cu 2+ are colored blue. There are also compounds in which M. is 3-valent. Thus, by the action of sodium peroxide on a solution of sodium cuprite na 2 cuo 2, oxide cu 2 o 3 was obtained - a red powder, which begins to give up oxygen already at 100 ° C. cu 2 o 3 is a strong oxidizing agent (for example, it releases chlorine from hydrochloric acid).

The chemical activity of M. is small. Compact metal at temperatures below 185 ° C does not interact with dry air and oxygen. In the presence of moisture and co 2 , a green film of basic carbonate forms on the surface of the mineral. When heated in air, surface oxidation occurs; below 375 °C, cuo is formed, and in the range of 375-1100 °C, with incomplete oxidation of mineral, a two-layer scale is formed, in the surface layer of which there is cuo, and in the inner layer - cu 2 o. Wet chlorine interacts with M. even at ordinary temperatures, forming cucl 2 chloride, which is highly soluble in water. M. easily combines with other halogens. M. has a special affinity for sulfur and selenium; so, it burns in sulfur fumes. M. does not react with hydrogen, nitrogen, and carbon even at high temperatures. The solubility of hydrogen in solid M. is negligible and at 400 °C is 0.06 mg at 100 G M. Hydrogen and other combustible gases (co, ch 4), acting at high temperature on M. ingots containing cu 2 o, reduce it to metal with the formation of co 2 and water vapor. These products, being insoluble in M., stand out from it, causing the appearance of cracks, which sharply worsens the mechanical properties of M.

When nh 3 is passed over a red-hot M., cu 3 n is formed. Already at a heating temperature, M. is exposed to nitrogen oxides, namely no, n 2 o (with the formation of cu 2 o) and no 2 (with the formation of cuo). Carbides cu 2 c 2 and cuc 2 can be obtained by the action of acetylene on ammonia solutions of M salts. The normal electrode potential of M. for the reaction cu 2+ + 2e ® Cu is +0.337 in, and for the reaction cu2+ + e -> Сu is +0.52 in. Therefore, M. is displaced from its salts by more electronegative elements (iron is used in industry) and does not dissolve in non-oxidizing acids. M. dissolves in nitric acid with the formation of cu (no 3) 2 and nitrogen oxides, in a hot concentration of h 2 so 4 - with the formation of cuso 4 and so 2, in heated dilute h 2 so 4 - when blowing through a solution of air. All M. salts are poisonous.

M. in the bi- and monovalent state forms numerous very stable complex compounds. Examples of complex compounds of monovalent M.: (nh 4) 2 cubr 3; k 3 cu(cn) 4 - double salt complexes; [Сu (sc (nh 2)) 2 ]ci and others. Examples of complex compounds of 2-valent M.: cscuci 3, k 2 cucl 4 - type of double salts. Of great industrial importance are ammonia complex compounds M.: [Cu (nh 3) 4] so 4, [Cu (nh 3) 2] so 4.

In most modern factories, melting is carried out in reverberatory or electric furnaces. In reverberatory furnaces, the working space is extended in a horizontal direction; hearth area 300 m 2 and more (30 m? 10 m), the heat necessary for melting is obtained by burning carbonaceous fuel (natural gas, fuel oil, pulverized coal) in the gas space above the bath surface. In electric furnaces, heat is obtained by passing an electric current through the molten slag (the current is supplied to the slag through graphite electrodes immersed in it).

Rich lumpy sulfide ores (2-3% cu) with a high sulfur content (35-42% s) in some cases are directly sent for smelting in shaft furnaces (furnaces with a vertically located working space). In one of the varieties of shaft smelting (copper-sulphur smelting), fine coke is added to the charge, which reduces so 2 to elemental sulfur in the upper horizons of the furnace. Copper is also concentrated in the matte in this process.

The liquid matte obtained during melting (mainly cu 2 s, fes) is poured into the converter - a cylindrical tank made of sheet steel, lined with magnesite bricks from the inside, equipped with a side row of tuyeres for blowing air and a device for turning around the axis. Compressed air is blown through the matte layer. The matte conversion proceeds in two stages. First, iron sulfide is oxidized, and quartz is added to the converter to bind the iron oxides; converter slag is formed. Then copper sulfide is oxidized to form metal metal and so 2 . This draft M. is poured into molds. Ingots (and sometimes directly molten crude steel) are sent for fire refining in order to extract valuable satellites (au, ag, se, fe, bi, and others) and remove harmful impurities. It is based on the greater affinity of impurity metals for oxygen than that of copper: fe, zn, co and partially ni and others pass into slag in the form of oxides, and sulfur (in the form of so 2) is removed with gases. After removing the slag, metal is “teased” to restore the cu 2 o dissolved in it by immersing the ends of raw birch or pine logs in liquid metal, after which it is cast into flat molds. For electrolytic refining, these ingots are suspended in a bath with a solution of cuso 4 acidified with h 2 so 4 . They serve as anodes. When a current is passed, the anodes dissolve, and pure M. is deposited on cathodes—thin copper sheets, also obtained by electrolysis in special matrix baths. Surface-active additives (carpenter's glue, thiourea, and others) are introduced into the electrolyte to isolate dense, smooth precipitates. The resulting cathodic mineral is washed with water and remelted. Noble metals, se, te and other valuable satellites of M. are concentrated in the anode sludge, from which they are extracted by special processing. Nickel concentrated in the electrolyte; by removing part of the solutions for evaporation and crystallization, it is possible to obtain ni in the form of nickel vitriol.

Along with pyrometallurgical methods, hydrometallurgical methods are also used to obtain minerals (mainly from poor oxidized and native ores). These methods are based on the selective dissolution of copper-containing minerals, usually in weak solutions of h 2 so 4 or ammonia. M.'s solution is either precipitated with iron or isolated by electrolysis with insoluble anodes. Very promising for mixed ores are combined hydroflotation methods, in which the oxygen compounds of minerals are dissolved in sulfuric acid solutions, and sulfides are isolated by flotation. Autoclave hydrometallurgical processes proceeding at elevated temperatures and pressures are also gaining ground.

Application. The great role of magnetism in technology is due to a number of its valuable properties, primarily its high electrical conductivity, plasticity, and thermal conductivity. Thanks to these properties, M. is the main material for wires; over 50% of the mined mineral is used in the electrical industry. All impurities reduce the electrical conductivity of metal, and therefore, in electrical engineering, high-grade metal containing at least 99.9% cu is used. High thermal conductivity and corrosion resistance make it possible to manufacture critical parts of heat exchangers, refrigerators, vacuum apparatuses, etc. from M. About 30-40% M. is used in the form of various alloys, among which the most important are brass(from 0 to 50% zn) and various types bronze; tin, aluminum, lead, beryllium, etc. In addition to the needs of heavy industry, communications, and transport, a certain amount of mineral (mainly in the form of salts) is consumed for the preparation of mineral pigments, the control of pests and plant diseases, as microfertilizers, and catalysts oxidation processes, as well as in the leather and fur industry and in the production of rayon.

L. V. Vanyukov.

Copper as an art material is used with copper age(decorations, sculpture, utensils, dishes). Forged and cast items made of metal and alloys are decorated with embossing, engraving, and embossing. The ease of processing marble (due to its softness) allows craftsmen to achieve a variety of textures, thoroughness in working out details, and fine modeling of form. Products from M. are distinguished by the beauty of golden or reddish tones, as well as the property of gaining shine when polished. M. is often gilded, patinated, tinted, decorated with enamel. Since the 15th century, M. has also been used for the manufacture of printing plates.

Copper in the body. M. - necessary for plants and animals trace element. M.'s main biochemical function is participation in enzymatic reactions as an activator or as part of copper-containing enzymes. The amount of M. in plants ranges from 0.0001 to 0.05% (per dry matter) and depends on the type of plant and the content of M. in the soil. In plants M. is a part of enzymes oxidases and plastocyanin protein. In optimal concentrations, M. increases the cold resistance of plants, promotes their growth and development. Among animals, the richest in M. are some invertebrates (in mollusks and crustaceans in hemocyanin contains 0.15-0.26% M.). Acting with food, M. is absorbed in the intestine, binds to the blood serum protein - albumin, then is absorbed by the liver, from where it returns to the blood as part of the ceruloplasmin protein and is delivered to organs and tissues.

With a lack of M., cereal plants are affected by the so-called processing disease, fruit plants - by exanthema; in animals, the absorption and use of iron is reduced, which leads to anemia accompanied by diarrhea and emaciation. Copper microfertilizers and feeding of animals with M. salts are used. M. poisoning leads to anemia, liver disease, and Wilson's disease. In humans, poisoning rarely occurs due to the subtle mechanisms of absorption and excretion of M. However, in large doses, M. causes vomiting; when M. is absorbed, general poisoning can occur (diarrhea, weakening of breathing and cardiac activity, suffocation, coma).

I. F. Gribovskaya.

Lit.: Smirnov V.I., Metallurgy of copper and nickel, Sverdlovsk - M., 1950; Avetisyan H. K., Blister copper metallurgy, M., 1954; Gazaryan L. M., Pyrometallurgy of copper, M., 1960; Metallurgist's reference book on non-ferrous metals, edited by N. N. Murach, 2nd ed., vol. 1, M., 1953, vol. 2, M., 1947; Levinson N. p., [Products from non-ferrous and ferrous metal], in the book: Russian decorative art, vol. 1-3, M., 1962-65; hadaway w. s., illustrations of metal work in brass and copper mostly south indian, madras, 1913; wainwright g. a., the occurrence of tin and copper near bybios, "journal of egyptian archeology", 1934, v. 20, pt 1, p. 29-32; bergs? e p., the gilding process and the metallurgy of copper and lead among the precolumbian indians, kbh., 1938; Frieden E., The role of copper compounds in nature, in the book: Horizons of Biochemistry, translated from English, M., 1964; his own. Biochemistry of copper, in the book: Molecules and cells, translated from English, in. 4, M., 1969; Biological role of copper, M., 1970.

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"Mendeleev's periodic law" - D.I. Mendeleev was present as an observer. Congress of chemists in Karlsruhe in 1860. 1829. The role of practice in the development of theory. Law of Octave. The main directions of development of the theory. Periodic law of D.I. Mendeleev. Prerequisites for the creation of the law. Personal qualities of a scientist. (1834-1907). The periodic law of D.I. Mendeleev was discovered in 1869.

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"The life and work of Mendeleev" - Ivan Pavlovich Mendeleev (1783 - 1847), father of the scientist. DI. Menedeleev (South Kazakhstan region, Shymkent city). Libraries. 1834, January 27 (February 6) - D.I. Mendeleev was born in the city of Tobolsk, in Siberia. “If you do not know the names, then the knowledge of things will die” K. Liney. Geography. DI Mendeleev (Moscow) Charitable Public Foundation for the Preservation of the Heritage of DI Mendeleev "BOBLOVO".