Metallic copper: description of the element, properties and application. Copper - properties of copper, alloys and applications

History of copper

Copper is called one of the first metals that man mastered in ancient times and uses it to this day. Copper mining was affordable because the ore had to be smelted at a relatively low temperature. The first ore from which copper began to be mined was malachite ore (calorizator). The Stone Age in human history changed precisely copper, when household items, tools and weapons made of copper became most widespread.

Copper is an element of group XI of period IV of the periodic table of chemical elements D.I. Mendeleev, has atomic number 29 and atomic mass 63.546. The accepted designation is Cu(from Latin Cuprum).

Being in nature

Copper is quite widely represented in the earth's crust, in sedimentary rocks, in marine and fresh waters, and in shales. Distributed both in the form of connections and in an independent version.

Physical and chemical properties

Copper is a ductile, so-called transition metal, and has a golden-pink color. Upon contact with air, an oxide film forms on the surface of copper, giving the metal a yellowish-red tint. The main alloys of copper are known - with zinc (brass), with tin (bronze), with nickel (cupronickel).

Daily copper requirement

The requirement for copper in an adult is 2 mg per day (about 0.035 mg/1 kg of weight).

Copper is one of the most important trace elements for the body, so foods rich in copper should be in everyone's diet. This:

• nuts, cereals,
• fish,
• cereals (especially and),
• dairy products
• , berries and

Signs of copper deficiency

Signs of an insufficient amount of copper in the body are: anemia and poor breathing, loss of appetite, stomach upset, nervousness, depression, fatigue, pigmentation disorders of the skin and hair, fragility and hair loss, rashes on the skin, frequent infections. Internal bleeding is possible.

Signs of Excess Copper

An excess of copper is characterized by insomnia, impaired brain activity, epilepsy, and problems with the menstrual cycle.

Interactions with others

It is assumed that copper and copper compete with each other during absorption in the digestive tract, so an excess of one of these elements in food can cause a deficiency of the other element.

Copper is of great importance in the national economy, its main use is in electrical engineering, but the metal is widely used for minting coins, often in works of art. Copper is also used in medicine, architecture and construction.

Beneficial properties of copper and its effect on the body

Required for the body's conversion to hemoglobin. Makes it possible to use the amino acid tyrosine, allowing it to exert its effect as a pigmentation factor in hair and skin. After copper is absorbed by the intestines, it is transported to the liver using albumin. Copper is also involved in the processes of growth and reproduction. Takes part in the formation of collagen and elastin and the synthesis of endorphins - hormones of “happiness”.

DEFINITION

Copper- the twenty-ninth element of the Periodic Table. Designation - Cu from the Latin "cuprum". Located in the fourth period, IB group. Refers to metals. The nuclear charge is 29.

The most important minerals that make up copper ores are: chalcocite, or copper luster Cu 2 S; chalcopyrite, or copper pyrite CuFeS 2; malachite (CuOH) 2 CO 3 .

Pure copper is a viscous, viscous metal of light pink color (Fig. 1), easily rolled into thin sheets. It conducts heat and electricity very well, second only to silver in this regard. In dry air, copper remains almost unchanged, since the thin film of oxides that forms on its surface (giving copper a darker color) serves as good protection against further oxidation. But in the presence of moisture and carbon dioxide, the copper surface becomes covered with a greenish coating of hydroxycopper carbonate (CuOH) 2 CO 3.

Rice. 1. Copper. Appearance.

Atomic and molecular mass of copper

DEFINITION

Relative molecular weight of the substance(M r) 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 relative atomic mass of an element(A r) - how many times the average mass of atoms of a chemical element is greater than 1/12 of the mass of a carbon atom.

Since in the free state chromium exists in the form of monatomic Cu molecules, the values ​​of its atomic and molecular masses coincide. They are equal to 63.546.

Isotopes of copper

It is known that in nature copper can be found in the form of two stable isotopes 63 Cu (69.1%) and 65 Cu (30.9%). Their mass numbers are 63 and 65, respectively. The nucleus of an atom of the copper isotope 63 Cu contains twenty-nine protons and thirty-four neutrons, and the isotope 65 Cu contains the same number of protons and thirty-six neutrons.

There are artificial unstable isotopes of copper with mass numbers from 52 to 80, as well as seven isomeric states of nuclei, among which the longest-lived isotope 67 Cu with a half-life of 62 hours.

Copper ions

The electronic formula demonstrating the orbital distribution of copper electrons is as follows:

1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 1 .

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

Cu 0 -1e → Cu + ;

Cu 0 -2e → Cu 2+ .

Copper molecule and atom

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

Copper alloys

The most important alloys of copper with other metals are brasses (alloys of copper and zinc), copper-nickel alloys and bronze.

Copper-nickel alloys are divided into structural and electrical. Structural stones include cupronickel and nickel silver. Cupronickel contains 20-30% nickel and small amounts of iron and manganese, while nickel silver contains 5-35% nickel and 13-45% zinc. Electrical copper-nickel alloys include constantan (40% nickel, 1.5% manganese), manganin (3% nickel and 12% manganese) and copel (43% nickel and 0.5% manganese).

Bronzes are divided according to the main component in their composition (except copper) into tin, aluminum, silicon, etc.

Examples of problem solving

EXAMPLE 1

EXAMPLE 2

Copper

Copper(lat. Cuprum) is a chemical element of group I of the periodic system of Mendeleev (atomic number 29, atomic mass 63.546). In compounds, copper usually exhibits oxidation states +1 and +2; a few trivalent copper compounds are also known. The most important copper compounds: oxides Cu 2 O, CuO, Cu 2 O 3; hydroxide Cu(OH) 2, nitrate Cu(NO 3) 2. 3H 2 O, CuS sulfide, sulfate (copper sulfate) CuSO 4. 5H 2 O, carbonate CuCO 3 Cu(OH) 2, chloride CuCl 2. 2H2O.

Copper- one of the seven metals known since ancient times. The transition period from the Stone to the Bronze Age (4th - 3rd millennium BC) was called copper age or Chalcolithic(from the Greek chalkos - copper and lithos - stone) or Chalcolithic(from Latin aeneus - copper and Greek lithos - stone). Copper tools appeared during this period. It is known that copper tools were used during the construction of the Cheops pyramid.

Pure copper is a malleable and soft metal of a reddish color, pink when fractured, in places with brown and mottled tarnish, heavy (density 8.93 g/cm3), an excellent conductor of heat and electricity, second in this regard only to silver (melting point 1083 ° C). Copper is easily drawn into wire and rolled into thin sheets, but has relatively little activity. In dry air and oxygen under normal conditions, copper does not oxidize. But it reacts quite easily: already at room temperature with halogens, for example with wet chlorine, it forms CuCl 2 chloride, when heated with sulfur it forms Cu 2 S sulfide, with selenium. But copper does not interact with hydrogen, carbon and nitrogen even at high temperatures. Acids that do not have oxidizing properties do not act on copper, for example, hydrochloric and dilute sulfuric acids. But in the presence of atmospheric oxygen, copper dissolves in these acids to form the corresponding salts: 2Cu + 4HCl + O2 = 2CuCl2 + 2H2O.

In an atmosphere containing CO 2, H 2 O vapors, etc., it becomes covered with patina - a greenish film of basic carbonate (Cu 2 (OH) 2 CO 3)), a toxic substance.

Copper is included in more than 170 minerals, of which only 17 are important for industry, including: bornite (variegated copper ore - Cu 5 FeS 4), chalcopyrite (copper pyrite - CuFeS 2), chalcocite (copper luster - Cu 2 S) , covellite (CuS), malachite (Cu 2 (OH) 2 CO 3). Native copper is also found.

Copper density, specific gravity of copper and other characteristics of copper

Density - 8.93*10 3 kg/m 3 ;
Specific gravity - 8.93 g/cm3;
Specific heat capacity at 20 °C - 0.094 cal/deg;
Melting temperature - 1083 °C;
Specific heat of fusion - 42 cal/g;
Boiling temperature - 2600 °C;
Linear expansion coefficient(at a temperature of about 20 °C) - 16.7 * 10 6 (1/deg);
Coefficient of thermal conductivity - 335kcal/m*hour*deg;
Resistivity at 20 °C - 0.0167 Ohm*mm 2 /m;

Copper elastic moduli and Poisson's ratio

COPPER COMPOUNDS

Copper (I) oxide Cu 2 O 3 and cuprous oxide (I) Cu2O, like other copper (I) compounds, are less stable than copper (II) compounds. Copper (I) oxide, or copper oxide Cu 2 O, occurs in nature as the mineral cuprite. In addition, it can be obtained as a precipitate of red copper(I) oxide by heating a solution of a copper(II) salt and an alkali in the presence of a strong reducing agent.

Copper(II) oxide, or copper oxide, CuO- a black substance found in nature (for example, in the form of the mineral tenerite). It is obtained by calcination of copper (II) hydroxycarbonate (CuOH) 2 CO 3 or copper (II) nitrate Cu(NO 2) 2.
Copper(II) oxide is a good oxidizing agent. Copper (II) hydroxide Cu(OH) 2 precipitates from solutions of copper (II) salts under the action of alkalis in the form of a blue gelatinous mass. Even with low heating, even under water, it decomposes, turning into black copper (II) oxide.
Copper(II) hydroxide is a very weak base. Therefore, solutions of copper (II) salts in most cases have an acidic reaction, and with weak acids copper forms basic salts.

Copper (II) sulfate CuSO 4 in an anhydrous state it is a white powder, which turns blue when absorbing water. Therefore, it is used to detect traces of moisture in organic liquids. An aqueous solution of copper sulfate has a characteristic blue-blue color. This color is characteristic of hydrated 2+ ions, therefore all dilute solutions of copper (II) salts have the same color, unless they contain any colored anions. From aqueous solutions, copper sulfate crystallizes with five molecules of water, forming transparent blue crystals of copper sulfate. Copper sulfate is used for electrolytic coating of metals with copper, for the preparation of mineral paints, and also as a starting material in the preparation of other copper compounds. In agriculture, a diluted solution of copper sulfate is used to spray plants and treat grain before sowing to destroy spores of harmful fungi.

Copper (II) chloride CuCl 2. 2H2O. Forms dark green crystals, easily soluble in water. Very concentrated solutions of copper (II) chloride are green, diluted solutions are blue-blue.

Copper (II) nitrate Cu(NO 3) 2. 3H2O. It is obtained by dissolving copper in nitric acid. When heated, blue copper nitrate crystals first lose water and then easily decompose, releasing oxygen and brown nitrogen dioxide, turning into copper (II) oxide.

Copper (II) hydroxycarbonate (CuOH) 2 CO 3. It occurs naturally in the form of the mineral malachite, which has a beautiful emerald green color. It is artificially prepared by the action of Na 2 CO 3 on solutions of copper (II) salts.
2CuSO 4 + 2Na 2 CO 3 + H 2 O = (CuOH) 2 CO 3 ↓ + 2Na 2 SO 4 + CO 2
It is used for the production of copper (II) chloride, for the preparation of blue and green mineral paints, as well as in pyrotechnics.

Copper (II) acetate Cu (CH 3 COO) 2. H2O. It is obtained by treating copper metal or copper(II) oxide with acetic acid. Usually it is a mixture of basic salts of various compositions and colors (green and blue-green). Under the name verdigris, it is used to prepare oil paint.

Complex copper compounds are formed as a result of the combination of doubly charged copper ions with ammonia molecules.
A variety of mineral paints are obtained from copper salts.
All copper salts are poisonous. Therefore, to avoid the formation of copper salts, copper utensils are coated on the inside with a layer of tin (tinned).

COPPER PRODUCTION

Copper is mined from oxide and sulfide ores. 80% of all mined copper is smelted from sulfide ores. Typically, copper ores contain a lot of gangue. Therefore, a beneficiation process is used to obtain copper. Copper is obtained by smelting it from sulfide ores. The process consists of a number of operations: roasting, smelting, converting, fire and electrolytic refining. During the firing process, most of the impurity sulfides are converted into oxides. Thus, the main impurity of most copper ores, pyrite FeS 2, turns into Fe 2 O 3. The gases produced during roasting contain CO 2, which is used to produce sulfuric acid. The resulting oxides of iron, zinc and other impurities during the firing process are separated in the form of slag during melting. Liquid copper matte (Cu 2 S with an admixture of FeS) enters the converter, where air is blown through it. During conversion, sulfur dioxide is released and crude or raw copper is obtained. To extract valuable (Au, Ag, Te, etc.) and to remove harmful impurities, blister copper is first subjected to fire and then electrolytic refining. During fire refining, liquid copper is saturated with oxygen. In this case, impurities of iron, zinc and cobalt are oxidized, turn into slag and are removed. And copper is poured into molds. The resulting castings serve as anodes during electrolytic refining.
The main component of the solution during electrolytic refining is copper sulfate - the most common and cheapest copper salt. To increase the low electrical conductivity of copper sulfate, sulfuric acid is added to the electrolyte. And to obtain a compact copper deposit, a small amount of additives is introduced into the solution. Metal impurities contained in unrefined (“blister”) copper can be divided into two groups.

1)Fe, Zn, Ni, Co. These metals have significantly more negative electrode potentials than copper. Therefore, they anodicly dissolve together with copper, but are not deposited on the cathode, but accumulate in the electrolyte in the form of sulfates. Therefore, the electrolyte must be replaced periodically.

2)Au, Ag, Pb, Sn. Noble metals (Au, Ag) do not undergo anodic dissolution, but during the process settle at the anode, forming anode sludge together with other impurities, which is periodically removed. Tin and lead dissolve together with copper, but in the electrolyte they form poorly soluble compounds that precipitate and are also removed.

COPPER ALLOYS

Alloys, which increase the strength and other properties of copper, are obtained by introducing additives into it, such as zinc, tin, silicon, lead, aluminum, manganese, and nickel. More than 30% of copper is used for alloys.

Brass- alloys of copper and zinc (copper from 60 to 90% and zinc from 40 to 10%) - stronger than copper and less susceptible to oxidation. When silicon and lead are added to brass, its anti-friction qualities increase; when tin, aluminum, manganese and nickel are added, its anti-corrosion resistance increases. Sheets and cast products are used in mechanical engineering, especially in chemical, optics and instrument making, and in the production of meshes for the pulp and paper industry.

Bronze. Previously, bronzes were alloys of copper (80-94%) and tin (20-6%). Currently, tin-free bronzes are produced, named after the main component after copper.

Aluminum bronzes contain 5-11% aluminum, have high mechanical properties combined with anti-corrosion resistance.

Lead bronzes, containing 25-33% lead, are used mainly for the manufacture of bearings operating at high pressures and high sliding speeds.

Silicon bronzes, containing 4-5% silicon, are used as cheap substitutes for tin bronzes.

Beryllium bronzes, containing 1.8-2.3% beryllium, are distinguished by hardness after hardening and high elasticity. They are used for the manufacture of springs and spring products.

Cadmium bronzes- copper alloys with a small amount of cadmium (up to 1%) - are used for the manufacture of fittings for water and gas lines and in mechanical engineering.

Solders- alloys of non-ferrous metals used in soldering to obtain a monolithic soldered seam. Among hard solders, copper-silver alloy is known (44.5-45.5% Ag; 29-31% Cu; the rest is zinc).

USES OF COPPER

Copper, its compounds and alloys are widely used in various industries.

In electrical engineering, copper is used in its pure form: in the production of cable products, busbars of bare and contact wires, electric generators, telephone and telegraph equipment and radio equipment. Heat exchangers, vacuum devices, and pipelines are made from copper. More than 30% of copper goes to alloys.

Alloys of copper with other metals are used in mechanical engineering, in the automotive and tractor industries (radiators, bearings), and for the manufacture of chemical equipment.

The high viscosity and ductility of the metal make it possible to use copper for the manufacture of a variety of products with very complex patterns. Red copper wire in the annealed state becomes so soft and flexible that you can easily twist all kinds of cords from it and bend the most complex ornamental elements. In addition, copper wire is easily soldered with hard silver solder and is well silvered and gold-plated. These properties of copper make it an indispensable material in the production of filigree products.

The coefficient of linear and volumetric expansion of copper when heated is approximately the same as that of hot enamels, and therefore, when cooled, the enamel adheres well to the copper product and does not crack or bounce off. Thanks to this, craftsmen prefer copper to all other metals for the production of enamel products.

Like some other metals, copper is one of the vital microelements. She is involved in the process photosynthesis and the absorption of nitrogen by plants, promotes the synthesis of sugar, proteins, starch, and vitamins. Most often, copper is added to the soil in the form of pentahydrate sulfate - copper sulfate CuSO 4. 5H 2 O. In large quantities it is poisonous, like many other copper compounds, especially for lower organisms. In small doses, copper is necessary for all living things.

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

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

According to historians, society has been familiar with copper for about nine thousand years. The most ancient copper products were found during archaeological excavations in the area of ​​modern Turkey. Archaeologists have discovered small copper beads and plates used to decorate clothing. The finds date back to the turn of the 8th-7th millennium BC. In ancient times, copper was used to make jewelry, expensive dishes, and various tools with thin blades.

A great achievement of 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 have a greenish-blue color when examined through them. In its pure form, copper is quite soft, malleable 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 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 densities, melting points and boiling points. An important property is also good resistance to corrosion. For example, at high humidity, iron oxidizes much faster.

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

Copper is a relatively low-active metal. Under normal conditions in dry air, its oxidation does not occur. It reacts easily with halogens, selenium and sulfur. Acids without oxidizing properties have no effect on copper. There are no chemical reactions with hydrogen, carbon and nitrogen. In humid air, oxidation occurs to form copper (II) carbonate - the top layer of platinum.
Copper is amphoteric, meaning 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 luster. The copper content in them is 1-2%. 90% of primary copper is mined using the pyrometallurgical method and 10% using the hydrometallurgical method.

1. The pyrometallurgical method includes the following processes: enrichment and roasting, smelting for matte, purging in a 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 you to obtain 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 reduced by almost half. Poor concentrates containing 8-25% copper are roasted. Rich concentrates containing 25-35% copper are melted without resorting to roasting.

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

In horizontal converters with side blowing, the copper matte is blown with compressed air in order for the oxidation of sulfides and ferrum to occur. Next, the resulting oxides are converted into slag, and sulfur into oxide. The converter produces blister copper, which contains 98.4-99.4% copper, iron, sulfur, as well as small amounts of nickel, tin, silver and gold.

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

2. The hydrometallurgical method involves leaching copper with a weak solution of sulfuric acid, and then separating copper metal directly from the solution. This method is used for processing low-grade ores and does not allow for the associated extraction of precious metals along with copper.

Copper Applications

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, and gold. Less commonly used are 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 is highly environmentally friendly, 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 or painting.

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

Copper compounds are characterized by high biological activity. In plants, copper takes part 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 deterioration in blood composition. It is found in many food products. For example, this metal is found in milk. However, it is important to remember that excess copper compounds can cause poisoning. This is why you should not cook food in copper cookware. During boiling, large amounts of copper can leach 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.

People learned to smelt the hard metal copper even before our era. The name of the element on the periodic table is Cuprum, in honor of the first mass production of copper. It was on the island of Cyprus in the third millennium BC. began to mine ore. The metal has proven itself to be a good weapon and a beautiful, shiny material for making dishes and other utensils.

Copper smelting process

Making items required a lot of effort in the absence of technology. In the first steps of the development of civilization and the search for new metals, people learned to mine and smelt copper ore. The ore was obtained in the malachite rather than sulfide state. Obtaining free copper at the output, from which parts can be made, required firing. To eliminate oxides, metal with charcoal was placed in a clay vessel. The metal was set on fire in a specially prepared pit, and the carbon monoxide generated in the process contributed to the process of the appearance of free copper.

For accurate calculations, a copper melting graph was used. At that time, precise calculations were made of the time and approximate temperature at which copper smelting occurs.

Copper and its alloys

The metal has a reddish-yellow hue due to the oxide film that forms when the metal first interacts with oxygen. The film gives a noble appearance and has anti-corrosion properties.

There are several methods of metal mining available now. Copper pyrite and luster, which occur in the form of sulfide ores, are common. Each copper production technology requires a special approach and following the process.

Mining in natural conditions occurs in the form of searching for copper shale and nuggets. Large deposits in the form of sedimentary rocks are located in Chile, and copper sandstones and shales are located in Kazakhstan. The use of metal is due to its low melting point. Almost all metals melt by destroying the crystal lattice.

Basic melting order and properties:

• at temperature thresholds from 20 to 100°, the material completely retains its properties and appearance, the upper oxide layer remains in place;
• the crystal lattice disintegrates at 1082°, the physical state becomes liquid and the color white. The temperature level lingers for a while and then continues to rise;
• The boiling point of copper begins at 2595°, carbon is released, and characteristic bubbling occurs;
• When the heat source is turned off, the temperature decreases and a transition to the solid stage occurs.

Copper smelting is possible at home, subject to certain conditions. The stages and complexity of the task depend on the choice of equipment.

Physical properties

Main characteristics of the metal:

• in its pure form, the density of the metal is 8.93 g/cm3;
• good electrical conductivity with an indicator of 55.5 S, at a temperature of about 20⁰;
• heat transfer 390 J/kg;
• boiling occurs at around 2600°, after which the release of carbon begins;
• electrical resistivity in the average temperature range – 1.78×10 Ohm/m.

The main areas of exploitation of copper are electrical purposes. High heat transfer and plasticity make it possible to apply to various tasks. Alloys of copper with nickel, brass, bronze make the cost more acceptable and improve the characteristics.

In nature, it is not homogeneous in composition, since it contains a number of crystalline elements that form a stable structure with it, so-called solutions, which can be divided into three groups:

1. Solid solutions. They are formed if the composition contains impurities of iron, zinc, antimony, tin, nickel and many other substances. Such occurrences significantly reduce its electrical and thermal conductivity. They complicate the hot form of pressure processing.
2. Impurities dissolving in the copper grid. These include bismuth, lead and other components. They do not impair the quality of electrical conductivity, but make processing under pressure more difficult.
3. Impurities that form brittle chemical compounds. This includes oxygen and sulfur, as well as other elements. They impair strength properties, including reducing electrical conductivity.

The mass of copper with impurities is much greater than in its pure form. In addition, impurity elements significantly affect the final characteristics of the finished product. Therefore, their total composition, including quantitative ones, must be separately regulated at the production stage. Let us consider in more detail the influence of each element on the characteristics of the final copper products.

1. Oxygen. One of the most undesirable elements for any material, not just copper. As it grows, quality such as ductility and resistance to corrosion processes deteriorates. Its content should not exceed 0.008%. During heat treatment, as a result of oxidation processes, the quantitative content of this element decreases.
2. Nickel. Forms a stable solution and significantly reduces conductivity.
3. Sulfur or selenium. Both components have the same effect on the quality of the finished product. A high concentration of such occurrences reduces the ductile properties of copper products. The content of such components should not exceed 0.001% of the total mass.
4. Bismuth. Negatively affects the mechanical and technological characteristics of the finished product. The maximum content should not exceed 0.001%.
5. Arsenic. It does not change its properties, but forms a stable solution and is a kind of protector from the harmful effects of other elements such as oxygen, antimony or bismuth.

1. Manganese. It is able to completely dissolve in copper at almost room temperature. Affects current conductivity.
2. Antimony. The component dissolves best in copper and causes minimal harm to it. Its content should not exceed 0.05% by weight of copper.
3. Tin. Forms a stable solution with copper and increases its heat-conducting properties.
4. Zinc. Its content is always minimal, so it does not have such a harmful effect.

Phosphorus. The main copper deoxidizer, the maximum content of which at a temperature of 714°C is 1.7%.

An alloy based on copper with the addition of zinc is called brass. In some situations, tin is added in smaller proportions. James Emerson decided to patent the combination in 1781. The zinc content in the alloy can vary from 5 to 45%. Brass is distinguished depending on its purpose and specification:

• simple, consisting of two components - copper and zinc. The marking of such alloys is indicated by the letter “L”, directly indicating the copper content in the alloy as a percentage;
• multi-component brasses - contain many other metals depending on their intended use. Such alloys increase the performance properties of products; they are also designated by the letter “L”, but with the addition of numbers.

The physical properties of brass are relatively high, corrosion resistance is at an average level. Most alloys are not critical to low temperatures; it is possible to operate the metal in various conditions.
Technologies for producing brass interact with the processes of the copper and zinc industry, processing of secondary raw materials. An effective method of melting is to use an induction-type electric furnace with a magnetic tap and temperature control. After obtaining a homogeneous mass, it is poured into molds and subjected to deformation processes.

The use of the material in various industries increases the demand for it every year. The alloy is used in court construction and the production of ammunition, various bushings, adapters, bolts, nuts and plumbing materials.

Non-ferrous metal has been used for the manufacture of various types of products since ancient times. This fact is confirmed by materials found during archaeological excavations. The composition of bronze was originally rich in tin.

The industry produces a different number of varieties of bronze. An experienced craftsman is able to determine its purpose by the color of the metal. However, not everyone can determine the exact grade of bronze; markings are used for this. Methods for producing bronze are divided into casting, when melting and casting occurs, and deforming.

The composition of the metal depends on its intended use. The main indicator is the presence of beryllium. The increased concentration of the element in the alloy, subjected to a hardening procedure, can rival high-strength steels. The presence of tin in the composition takes away the flexibility and ductility of the metal.

The production of bronze alloys has changed since ancient times with the introduction of modern equipment. The technology using charcoal as a flux is still used today. Sequence for obtaining bronze:

• the furnace is heated to the required temperature, after which a crucible is installed in it;
• after melting, the metal may oxidize; to avoid this, flux is added as charcoal;
• Phosphorus copper serves as an acid catalyst; addition occurs after the alloy is completely heated.

Bronze smelting

Antique bronze products are subject to natural processes - patination. The greenish color with a white tint appears due to the formation of a film enveloping the product. Artificial patination methods include methods using sulfur and parallel heating to a certain temperature.

Melting point of copper

The material melts at a certain temperature, which depends on the presence and quantity of alloys in the composition.

In most cases, the process occurs at a temperature of 1085°. The presence of tin in the alloy gives a start; the melting of copper can begin at 950°. Zinc in the composition also lowers the lower limit to 900°.

For accurate timing calculations, you will need a copper melting chart. A graph is used on a regular piece of paper, with time marked horizontally and degrees vertically. The graph should indicate at what points the temperature is maintained during heating for the complete crystallization process.

Melting copper at home

At home, copper alloys can be melted in several ways. When using any of the methods, you will need the following materials:

• crucible - a vessel made of hardened copper or other refractory metal;
• charcoal will be needed as a flux;
• metal hook;
• the shape of the future product.

The easiest option for melting is a muffle furnace. Pieces of material are dropped into the container. After setting the melting temperature, the process can be observed through a special window. The installed door allows you to remove the oxide film formed during the process; for this you need a pre-prepared metal hook.

The second way to melt at home is to use a torch or cutter. Propane - oxygen flame is perfect for working with zinc or tin. Pieces of materials for the future alloy are placed in a crucible and heated by the master with arbitrary movements. The maximum melting point of copper can be achieved when exposed to a blue flame.

Melting copper at home involves working at elevated temperatures. Compliance with safety regulations is a priority. Before any procedure, you should wear protective fireproof gloves and thick clothing that completely covers the body.

Copper density value

Density is the ratio of mass to volume. It is expressed in kilograms per cubic meter of total volume. Due to the heterogeneity of the composition, the density value may vary depending on the percentage of impurities. Since there are different grades of rolled copper with different contents of components, their density values ​​will be different. The density of copper can be found in specialized technical tables, which is equal to 8.93x10 3 kg/m 3. This is a reference value. The same tables show the specific gravity of copper, which is 8.93 g/cm 3 . Not all metals are characterized by such a coincidence of density values ​​and its weight indicators.

It is no secret that the final mass of the manufactured product directly depends on density. However, for calculations it is much more correct to use specific gravity. This indicator is very important for the production of products from copper or any other metals, but is more applicable to alloys. It is expressed as the ratio of the mass of copper to the volume of the entire alloy.

Specific Gravity Calculation

Currently, scientists have developed a huge number of methods to help find the characteristics of the specific gravity of copper, which make it possible to calculate this important indicator even without resorting to specialized tables. Knowing it, you can easily select the necessary materials, thanks to which you can ultimately obtain the desired part with the required parameters. This is done at the preparation stage, when it is planned to create the necessary part from copper or its alloys containing it.

As mentioned above, the specific gravity of copper can be looked up in a specialized reference book, but if you don’t have one at hand, then it can be calculated using the following formula: divide the weight by the volume and get the value we need. In general terms, this ratio can be expressed as the total weight value to the total volume value of the entire product.

It should not be confused with the concept of density, since it characterizes the metal differently, although it has the same indicator values.

Let's consider how the specific gravity can be calculated if the mass and volume of the copper product are known.

For example, we have a pure copper sheet 5 mm thick, 2 m wide and 1 m long. First, let’s calculate its volume: 5 mm * 1000 mm (1 m = 1000 mm) * 2000 mm, which is 10,000,000 mm 3 or 10,000 cm 3. For convenience of calculations, we will assume that the mass of the sheet is 89 kg 300 grams or 89300 grams. We divide the calculated result by the volume and get 8.93 g/cm 3 . Knowing this indicator, we can always easily calculate the weight content of a particular alloy in copper. This is convenient, for example, for metal processing.

Units of specific gravity

Different measurement systems use different units to indicate the specific gravity of copper:

1. The CGS or centimeter-gram-second measurement system uses dyn/cm 3 .
2. The International SI units are n/m 3 .
3. In the MKSS or meter-kilogram-second-candle system, kg/m 3 is used.

The first two indicators are equal to each other, and the third, when converted, is equal to 0.102 kg/m 3.

Calculate weight using specific gravity values

Let's not go too far and use the example described above. Let's calculate the total copper content in 25 sheets. Let's change the condition and assume that the sheets are made of copper alloy. Thus, we take the specific gravity of copper from the table and it is equal to 8.93 g/cm3. The sheet thickness is 5 mm, the area (1000 mm * 2000 mm) is 2,000,000 mm, respectively, the volume will be 10,000,000 mm 3 or 10,000 cm 3. Now we multiply the specific gravity by the volume and get 89 kg and 300 g. We calculated the total volume of copper contained in these sheets without taking into account the weight of the impurities themselves, that is, the total weight value may be greater.

Now we multiply the calculated result by 25 sheets and get 2,235 kg. Such calculations are appropriate to use when processing copper parts, as they allow you to find out how much copper is contained in the original objects. Copper rods can be calculated in a similar way. The cross-sectional area of ​​the wire is multiplied by its length, where we get the volume of the rod, and then by analogy with the example described above.

How is density determined?

The density of copper, like the density of any other substance, is a reference value. It is expressed as the ratio of mass to volume. It is very difficult to independently calculate this indicator, since it is impossible to check the composition without special instruments.

Example of copper density calculation

The indicator is expressed in kilograms per cubic meter or grams per cubic centimeter. The density indicator is more useful for manufacturers who, based on available data, can assemble a particular part with the required properties and characteristics.

Areas of copper use

Due to its physical and mechanical properties, it is widely used in various industries. Most often it can be found in the electrical field as a component of an electrical wire. It is also equally popular in the production of heating and cooling systems, electronics and heat exchange systems.

In the construction industry, it is used primarily to create various types of structures that are produced much less in weight than from any other similar materials. It is often used for roofing, as such products are light and flexible. This material is easy to process and allows you to change the profile geometry, which is very convenient.

As mentioned above, it finds its main application in the manufacture of electrical and other conductive cables, where it is used for the manufacture of wire cores and cables. Possessing good electrical conductivity, it provides sufficient resistance to current electrons.

Copper alloys are also widely used, for example, an alloy of copper and gold increases the strength of the latter significantly.

Salt deposits never form on the walls of rolled copper. This quality is useful for transporting liquids and vapors.

Superconductors are made from copper oxides, and in its pure form it is used to make galvanic power supplies.

It is part of bronze, which is resistant to aggressive environments such as sea water. Therefore, it is often used in navigation. Bronze products can also be seen on the facades of houses, as a decorative element, since such an alloy is easy to process, as it is very plastic.