Presentation on the topic: Copper and its alloys. Presentation, report Copper and its alloys Copper and copper alloys presentation

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Presentation on the topic: Copper and its alloys

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History of copper. Copper has been known since time immemorial and is one of the “magnificent seven” of the oldest metals used by mankind - gold, silver, copper, iron, tin, lead and mercury. According to archaeological data, copper was known to people already 600 years ago. It turned out to be the first metal that replaced stone for ancient man in primitive tools. This was the beginning of the so-called. the Copper Age, which lasted about 2000 years. Axes, knives, maces, and household items were forged from copper and then smelted. According to legend, the ancient blacksmith god Hephaestus forged a shield of pure copper for the invincible Achilles. Stones for the 147-meter pyramid of Cheops.

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Now it is impossible to establish when It is impossible to establish when a person first became acquainted with copper. In any case, around 3000 BC. e. the Egyptians could already make wire from it. In nature, copper is sometimes found in a native state, and this made it easier for ancient craftsmen to extract. They knew how to forge various products from this metal using stone tools. Later, copper mines began to be developed, which were scattered throughout the planet: and in North America on the shores of the Great Lakes, and in Asia on the Sinai Peninsula, and in Europe in the territory of present-day Austria, and on the island of Cyprus. According to experts, the Latin name for the metal “cuprum” comes from the name of this island. The name of the metal, familiar to the Russian ear, “copper,” probably came from the Old Slavonic “smid,” which meant metal in general.

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Application of copper. Copper has long been used in construction: the ancient Egyptians built copper water pipes; the roofs of medieval castles and churches were covered with copper sheets, for example the famous royal castle in Elsinore (Denmark) was covered with copper roofing. Coins and jewelry were made from copper. Due to its low electrical resistance, copper is the main metal in electrical engineering: more than half of all copper produced is used in the production of electrical wires for high-voltage transmissions and low-current cables. Even insignificant impurities in copper lead to an increase in its electrical resistance and large losses of electricity. The hulls of ships are sheathed with copper tin. High thermal conductivity and corrosion resistance make it possible to manufacture copper parts for heat exchangers, refrigerators, vacuum devices, pipelines for pumping oils and fuels, etc. Copper is also widely used in electroplating when applying protective coatings to steel products. So, for example, when nickel or chrome plating steel objects, copper is pre-deposited on them; in this case, the protective coating lasts longer and is more effective. Copper is also used in electroplating (i.e., when replicating products by obtaining a mirror image), for example, in the manufacture of metal matrices for printing banknotes and reproducing sculptural products.

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Bronze products were in use Bronze products were in use among the ancient Egyptians, Assyrians, and Etruscans. Beautiful bronze statues were cast in Greece and Rome; many of them have survived to this day, such as the famous equestrian statue of Marcus Aurelius in Rome or one of the seven wonders of the world, the Colossus of Rhodes. For sculptural works standing outdoors, especially in places with a humid climate, bronze is preferable because over time, a dense greenish-brown coating, a patina, appears on its surface, which protects the metal from further oxidation. The shields of Roman legionnaires were also bound with bronze.

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It is from bronze that the “Bronze Horseman” praised by A.S. Pushkin in St. Petersburg and the monument to Minin and Pozharsky on Red Square in Moscow are cast from bronze. Due to its special mechanical properties and good casting qualities, bronze is an ideal metal for casting bells with a loud and beautiful sound. Everyone knows the giant “Tsar Bell” in the Moscow Kremlin, weighing almost 202 tons, cast in 1733-1735 by Russian masters I. F. and M. F. Matronin. In the old days, guns were also made from bronze; the largest of them, the Tsar Cannon (39.3 tons), was intended for the defense of the Moscow Kremlin and was cast by master A. Chokhov in 1586.

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And now sculptures are cast from bronze, And now sculptures are cast from bronze, chandeliers, candelabra, candlesticks, as well as parts of various mechanisms (for example, bearings) are made. As many centuries ago, copper and copper scrap are fused with tin to produce bronze. Only not in earthen ovens, but in modern electric ovens. So that copper and tin do not oxidize during melting, and bronze is especially durable, phosphorus compounds are added to the charge before casting. Due to the shortage of tin and its high price, tin bronze is gradually being replaced by other bronzes, Ch. arr. aluminum. Aluminum bronze, containing up to 11% Al, has good mechanical properties and is stable in sea water and even in dilute hydrochloric acid. This very durable alloy is used for the manufacture of pipelines, parts of steam turbines and aircraft engines, etc. “Copper” coins were minted from aluminum bronze in Russia from 1926 to 1957. Bearings for diesel locomotives, ship engines, and water turbines are made from lead bronze. Beryllium bronze is exceptionally strong and durable, which, due to its elastic properties, serves as a material for springs that practically do not know fatigue (withstand up to 20 million load cycles).

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Brass. Brass is an alloy of copper and zinc. Although zinc was discovered only in the Middle Ages, brass was known to the ancient Romans, who obtained it by smelting copper ores with zinc ores without access to air. To give brass the desired properties, alloying metals such as Al, Mn, Ni, Fe, etc. are often introduced into its composition in small quantities. Brass melts easier than copper, but it is harder. Brass is well forged, pierced into sheets, stamped, drawn into wire and highly polished (up to mirror shine). Products made from it can be hardened. If necessary, brass can be applied to the surface of other metals using the electrochemical method. It is important that brass is much cheaper than copper. Brass is used in mechanical engineering and electrical engineering; It is used to make parts of various mechanisms, water and gas taps, radiator pipes, door handles, hinges, and cartridge cases. Brass with aluminum addition appearance It looks like gold, badges, emblems, and medals are made from it. If there is relatively little zinc in the alloy (up to 18%), brasses have a reddish tint. For example, brass containing up to 10% zinc is called tombak; From this alloy, from 1961 to 1991, “copper” coins were minted in Russia, in denominations from 1 to 5 kopecks. Alloys with a high zinc content (up to 50%) are yellow in color and are called brasses. They are perfectly processed by rolling, pressing and drawing, and high-quality castings are obtained from them.

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Other alloys. Among other alloys, we note monel metal (50 - 70% copper, 15 - 25% nickel and zinc with additions of lead, tin and iron) was previously used for the manufacture of cutlery and jewelry “like silver”. Due to its high corrosion resistance and strength, good ductility, it is now used in the chemical, shipbuilding, medical, oil, textile and other industries. But constantan, manganin, chromel and copel almost do not change their resistance with significant temperature fluctuations and therefore faithfully serve in electrical engineering for the manufacture of thermocouples - very sensitive devices that measure temperature. Compensation wires, rheostats, and parts of heating devices are also made from chromel and copel. Mangonin is used to make reference resistors and elements of measuring instruments.

Introduction. It just so happened that in one subgroup there were copper, silver and gold: elements coeval with civilization. All of them at different times acted as the ultimate measure of values, in other words, money. These metals were used to forge weapons, make household utensils and jewelry. Nowadays, copper, silver and gold are in the thick of technological progress. The physicist will highlight their unsurpassed heat and electrical conductivity. The sculptor will note the plasticity and beautiful appearance. The jeweler and the minter will support him, and the chemist will certainly remember the noble inertness and high corrosion resistance of these metals. Golden mask of Pharaoh Tutankhamun. Gold nugget "Mephistopheles" weighing 20.25 g, found in Siberia. Diamond fund. Moscow. Silver nugget Monomakh's Cap. Bostock, late 13th early 14th centuries. Bowl. Ancient Rus' Chernigov, 12th century. Silver; forging, carving. It belonged to Prince Vladimir Davydovich of Chernigov.

Now it is impossible to establish when a person first became acquainted with copper. In any case, around 3000 BC. e. the Egyptians could already make wire from it. In nature, copper is sometimes found in a native state, and this made it easier for ancient craftsmen to extract. They knew how to forge various products from this metal using stone tools. Later, copper mines began to be developed, which were scattered throughout the planet: in North America on the shores of the Great Lakes, in Asia on the Sinai Peninsula, and in Europe in the territory of present-day Austria, and on the island of Cyprus. According to experts, the Latin name for the metal “cuprum” comes from the name of this island. The name of the metal, familiar to the Russian ear, “copper,” probably came from the Old Slavonic “smith,” which meant metal in general. Copper nugget.

Application of copper. Copper has long been used in construction: the ancient Egyptians built copper water pipes; the roofs of medieval castles and churches were covered with copper sheets, for example the famous royal castle in Elsinore (Denmark) was covered with copper roofing. Coins and jewelry were made from copper. Due to its low electrical resistance, copper is the main metal in electrical engineering: more than half of all copper produced is used in the production of electrical wires for high-voltage transmissions and low-current cables. Even insignificant impurities in copper lead to an increase in its electrical resistance and large losses of electricity. The hulls of ships are sheathed with copper tin. High thermal conductivity and corrosion resistance make it possible to manufacture copper parts for heat exchangers, refrigerators, vacuum devices, pipelines for pumping oils and fuels, etc. Copper is also widely used in electroplating when applying protective coatings to steel products. For example, when nickel or chrome plating steel objects, copper is pre-deposited on them; in this case, the protective coating lasts longer and is more effective. Copper is also used in electroplating (i.e., when replicating products by obtaining a mirror image), for example, in the manufacture of metal matrices for printing banknotes and reproducing sculptural products.

Bronze. Weapons made of bronze from the June period in China. Ancient metallurgists learned to extract copper from ores and add additives to it that improved the properties of the alloy. So, by mixing copper with tin, they got bronze. It was such an important stage in human history that we call it bronze age. The unusually simple method of obtaining the alloy (the flame of a fire melts a mixture of tin and copper) allowed craftsmen to make various tools, tools and, of course, weapons from it. Bronze is harder than copper, stable in air, easily processed into various products, but is more easily melted. The ancient Greeks, Mesopotamians, and Japanese craftsmen were able to produce especially high-quality alloys. Therefore, it is not at all accidental that the rise and decline of states were directly related to the degree of development of metallurgy.

Bronze products were in use among the ancient Egyptians, Assyrians, and Etruscans. Beautiful bronze statues were cast in Greece and Rome; many of them have survived to this day, such as the famous equestrian statue of Marcus Aurelius in Rome or one of the seven wonders of the world, the Colossus of Rhodes. For sculptural works standing outdoors, especially in places with a humid climate, bronze is preferable because over time, a dense greenish-brown coating, a patina, appears on its surface, which protects the metal from further oxidation. The shields of Roman legionnaires were also bound with bronze. Shield of a Roman legionnaire.

It is from bronze that the “Bronze Horseman” glorified by A. S. Pushkin in St. Petersburg and the monument to Minin and Pozharsky on Red Square in Moscow were cast. Due to its special mechanical properties and good casting qualities, bronze is an ideal metal for casting bells with a loud and beautiful sound. Everyone knows the giant “Tsar Bell” in the Moscow Kremlin, weighing almost 202 tons, cast by Russian masters I. F. and M. F. Matronin. In the old days, guns were also made from bronze; the largest of them, the Tsar Cannon (39.3 tons), was intended for the defense of the Moscow Kremlin and was cast by master A. Chokhov in 1586 by E. M. Falcone. "Bronze Horseman". Saint Petersburg. The Tsar Bell was cast by order of Empress Anna Ioannovna in the years. Moscow foundry workers Ivan Motorin and his son Mikhail replaced the Great Assumption Bell, which was broken in the city during a fire.

Tsar Cannon. Master Andrey Chokhov year. The monument to the tradesman Kuzma Minin and Prince Dmitry Pozharsky was created according to the design of the artist I. P. Martos and cast in bronze by the foundry master of the Academy of Arts V. P. Ekimov, opened on February 20, 1818.

And now sculptures are cast from bronze, chandeliers, candelabra, candlesticks, as well as parts of various mechanisms (for example, bearings) are made. As many centuries ago, copper and copper scrap are fused with tin to produce bronze. Only not in earthen ovens, but in modern electric ovens. So that copper and tin do not oxidize during melting, and bronze is especially durable, phosphorus compounds are added to the charge before casting. Due to the shortage of tin and its high price, tin bronze is gradually being replaced by other bronzes, Ch. arr. aluminum. Aluminum bronze, containing up to 11% Al, has good mechanical properties and is stable in sea water and even in dilute hydrochloric acid. This very durable alloy is used in the manufacture of pipelines, parts of steam turbines and aircraft engines, etc. “Copper” coins were minted from aluminum bronze in Russia from 1926 to 1957. Bearings for diesel locomotives, ship engines, and water turbines are made from lead bronze. Beryllium bronze is exceptionally strong and durable, which, due to its elastic properties, serves as a material for springs that practically do not know fatigue (withstand up to 20 million load cycles). Saint Petersburg. Bronze monument to Ostap Bender on Italianskaya Street. Sculptor Albert Charkin.

Brass. Brass is an alloy of copper and zinc. Although zinc was discovered only in the Middle Ages, brass was known to the ancient Romans, who obtained it by smelting copper ores with zinc ores without access to air. To give brass the desired properties, alloying metals such as Al, Mn, Ni, Fe, etc. are often introduced into its composition in small quantities. Brass melts easier than copper, but it is harder. Brass is well forged, pierced into sheets, stamped, drawn into wire and highly polished (to a mirror finish). Products made from it can be hardened. If necessary, brass can be applied to the surface of other metals using the electrochemical method. It is important that brass is much cheaper than copper. Brass is used in mechanical engineering and electrical engineering; It is used to make parts of various mechanisms, water and gas taps, radiator pipes, door handles, hinges and cartridge cases. Brass with the addition of aluminum is similar in appearance to gold; badges, emblems, and medals are made from it. If there is relatively little zinc in the alloy (up to 18%), brasses have a reddish tint. For example, brass containing up to 10% zinc is called tombak; From this alloy, from 1961 to 1991, “copper” coins were minted in Russia, in denominations from 1 to 5 kopecks. Alloys with a high zinc content (up to 50%) are yellow in color and are called brasses. They are perfectly processed by rolling, pressing and drawing, and high-quality castings are obtained from them.

Other alloys. Among other alloys, we note monel metal (% copper, % nickel and zinc with additions of lead, tin and iron) was previously used for the manufacture of cutlery and jewelry “like silver”. Due to its high corrosion resistance and strength, good ductility, it is now used in the chemical, shipbuilding, medical, oil, textile and other industries. But constantan, manganin, chromel and copel almost do not change their resistance with significant temperature fluctuations and therefore faithfully serve in electrical engineering for the manufacture of thermocouples - very sensitive devices that measure temperature. Compensation wires, rheostats, and parts of heating devices are also made from chromel and copel. Mangonin is used to make reference resistors and elements of measuring instruments.

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Now it is impossible to establish when It is impossible to establish when a person first became acquainted with copper. In any case, around 3000 BC. e. the Egyptians could already make wire from it. In nature, copper is sometimes found in a native state, and this made it easier for ancient craftsmen to extract. They knew how to forge various products from this metal using stone tools. Later, copper mines began to be developed, which were scattered throughout the planet: in North America on the shores of the Great Lakes, in Asia on the Sinai Peninsula, and in Europe in the territory of present-day Austria, and on the island of Cyprus. According to experts, the Latin name for the metal “cuprum” comes from the name of this island. The name of the metal, familiar to the Russian ear, “copper,” probably came from the Old Slavonic “smid,” which meant metal in general.

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Copper is a heavy pink-red metal, soft and malleable, its melting point is 1083 ° C, and is an excellent conductor. electric current and heat, the electrical conductivity of copper is 1.7 times higher than that of aluminum, and 6 times higher than that of iron. In everyday life, we always have to deal with copper and its alloys: we turn on a computer or a table lamp - current flows through copper wires, we use metal money, which, both yellow and white, are made from copper alloys. Some houses are decorated with bronze items, and dishes are made from copper. Meanwhile, copper is far from the most common element in nature: the copper content in the earth’s crust is 0.01%, which allows it to occupy only 23rd place among all elements.

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Copper is the first metal that people first began to use in ancient times several thousand years BC. The first copper tools were made from native copper, which is quite common. The largest copper nugget was found in the United States; it weighed 420 tons. But due to the fact that copper is a soft metal, copper in ancient times could not replace stone tools. Only when man learned to smelt copper and invented bronze (an alloy of copper and tin) did metal replace stone. The widespread use of copper began in the 4th millennium BC. e. Copper is a low-active metal; in the electrochemical series of voltages it is to the right of hydrogen. It does not interact with water, alkali solutions, hydrochloric and dilute sulfuric acid. However, in acids - strong oxidizing agents (for example, nitric and concentrated sulfuric acid) - copper dissolves: Cu + 4HMO3 - Cu(NO3)2 + 2NO+ 2H2O concentrated

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Copper has a fairly high resistance to corrosion. However, in a humid atmosphere containing carbon dioxide, copper is covered with a greenish coating of basic copper carbonate: 2Cu + O2 + CO2 + H2O = CU(OH)2 CuCO3 In compounds, copper can exhibit oxidation states +1, + 2 and +3, of which +2 - the most characteristic and stable. Copper (II) forms stable oxide CuO and hydroxide Cu(OH)2. This hydroxide is amphoteric, readily soluble in acids Cu(OH)2 + 2HCl = CuCl2 + 2H2O and in concentrated alkalis. Copper (II) salts are widely used in the national economy. Particularly important is copper sulfate - crystalline hydrate of copper (II) sulfate CuSO4 5H2.

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Copper and health The human body needs copper for the formation of various proteins and enzymes. Copper is needed: For the synthesis of hemoglobin For the formation of bones For the functioning of the circulatory system For the functioning of the central nervous system To obtain energy from cells Recent studies have shown that the assumption that a diet with insufficient copper content increases the risk of cardiovascular diseases is very close to the truth. Copper deficiency in the body can lead to such serious consequences as bone development defects, anemia and brain failure. Further consequences are: Blockage of cellular respiration Stopping the formation of uric acid Improper formation of neurotransmitters Stopping the formation of pigments (white hair) Disruption of the redox balance

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A person must receive a certain amount of copper with food in order to sufficiently saturate the body with this element. The daily requirement of an adult for copper is 2-3 mg. Many foods and drinks contain this important element in varying quantities. Single consumption drinking water with copper ions is not enough. Products with a high copper content include: Chocolate White and green beans Fish Hazelnuts and nuts The following products, on the contrary, contain copper only in small quantities: Cheese Milk White bread Beef and lamb This table shows a list of products and their copper content

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A technical metal containing 97 - 98% copper is released. One of the most important uses of copper is the electrical industry. Electrical wires are made from copper. For this purpose, the metal must be very pure: impurities sharply reduce electrical conductivity. The presence of 0.02% aluminum in copper will reduce its electrical conductivity by almost 10%. The resistance of the metal increases even more sharply in the presence of non-metallic impurities. To obtain pure copper, which can be used in electrical engineering, it is electrorefined. This method is based on electrolysis of an aqueous solution of copper salt with a soluble copper anode. Technical or blister copper, which serves as one of the electrodes, is immersed in a bath filled with an aqueous solution of copper sulfate. Another electrode is immersed in the bath. A direct current source is connected to the electrodes so that commercial copper becomes the anode (positive pole of the current source), and the other electrode becomes the cathode.

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A very important application of copper is the production of copper alloys. With many metals, copper forms so-called solid solutions, which are similar to ordinary solutions in that in them the atoms of one component (metal) are evenly distributed among the atoms of another (Fig. 34). Most copper alloys are solid solutions. A copper alloy known since ancient times - bronze - contains 4-30% tin (usually 8-10%). It is interesting that bronze is superior in its hardness to pure copper and tin taken separately. Bronze is more fusible than copper. Bronze products from masters of Ancient Egypt, Greece, and China have survived to this day. In the Middle Ages, tools and many other products were cast from bronze. The famous Tsar Cannon (Fig. 35) and the Tsar Bell in the Moscow Kremlin are also cast from an alloy of copper and tin.

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The healing properties of copper have been known for a very long time. The ancients believed that the healing effect of copper was associated with its analgesic, antipyretic, antibacterial and anti-inflammatory properties. Avicenna and Galen also described copper as a medicine, and Aristotle, pointing to the general strengthening effect of copper on the body, preferred to fall asleep with a copper ball in his hand. Queen Cleopatra wore the finest copper bracelets, preferring them to gold and silver, knowing medicine and alchemy well. In copper armor, ancient warriors were less tired, and their wounds festered less and healed faster. The ability of copper to positively influence “male strength” was noticed and widely used in the Ancient world. ethnoscience

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Nowadays, the use of copper products is widespread. In Central Asia they wear copper items and practically do not suffer from rheumatism. In Egypt and Syria, even children wear copper items. In France, hearing disorders are treated with copper. In the United States, copper bracelets are worn as remedies for arthritis. In Chinese medicine, copper disks are applied to active points. And in Nepal, copper is considered a sacred metal. Copper therapy (copper treatment) is one of the types of traditional medicine. As a child, on the advice of our grandmother, applying a copper penny to the bump, we reduced pain and inflammation, although in the 5-kopeck coin issued in Soviet time, the copper content was low. In copper therapy, products with a copper content of at least 99.9% are used. The simplest, most effective, aesthetically beautiful and practical means of medical therapy is a copper bracelet, approved and recommended by the Ministry of Health of the Russian Federation.

Copper is a heavy pink-red metal, soft and malleable, its melting point is 1083 ° C, it is an excellent conductor of electric current and heat; the electrical conductivity of copper is 1.7 times higher than aluminum and 6 times higher than iron. In everyday life, we always have to deal with copper and its alloys: when we turn on a computer or a table lamp, the current flows through copper wires, we use metal money, which, both yellow and white, are made from copper alloys. Some houses are decorated with bronze items, and dishes are made from copper. Meanwhile, copper is far from the most common element in nature: the copper content in the earth’s crust is 0.01%, which allows it to occupy only 23rd place among all elements.

Copper is the first metal that people first began to use in ancient times several thousand years BC. The first copper tools were made from native copper, which is quite common. The largest copper nugget was found in the United States; it weighed 420 tons. But due to the fact that copper is a soft metal, copper in ancient times could not replace stone tools. Only when man learned to smelt copper and invented bronze (an alloy of copper and tin) did metal replace stone. The widespread use of copper began in the 4th millennium BC. e. Copper is a low-active metal; in the electrochemical series of voltages it is to the right of hydrogen. It does not interact with water, alkali solutions, hydrochloric and dilute sulfuric acid. However, copper dissolves in strong oxidizing acids (for example, nitric and concentrated sulfuric acids): Cu + 4HMO3 - Cu(NO3)2 + 2NO+ 2H2O concentrated

Copper has a fairly high resistance to corrosion. However, in a humid atmosphere containing carbon dioxide, copper becomes covered with a greenish coating of basic copper carbonate: 2Cu + O2 + CO2 + H2O = CU(OH)2 CuCO3 In compounds, copper can exhibit oxidation states +1, +2 and +3, of which +2 the most characteristic and stable. Copper (II) forms stable oxide CuO and hydroxide Cu(OH)2. This hydroxide is amphoteric, readily soluble in acids Cu(OH)2 + 2HCl = CuCl2 + 2H2O and in concentrated alkalis. Copper (II) salts are widely used in the national economy. Particularly important is copper sulfate, crystalline hydrate of copper (II) sulfate CuSO4 5H2.

A person must receive a certain amount of copper with food in order to sufficiently saturate the body with this element. The daily requirement of an adult for copper is 2-3 mg. Many foods and drinks contain this important element in varying amounts. Consuming drinking water with copper ions alone is not enough. Products with a high copper content include: Chocolate White and green beans Fish Hazelnuts and nuts The following products, on the contrary, contain copper only in small quantities: Cheese Milk White bread Beef and lamb This table shows a list of products and their copper content

A technical metal containing 97–98% copper is isolated. One of the most important industries using copper is the electrical industry. Electrical wires are made from copper. For this purpose, the metal must be very pure: impurities sharply reduce electrical conductivity. The presence of 0.02% aluminum in copper will reduce its electrical conductivity by almost 10%. The resistance of the metal increases even more sharply in the presence of non-metallic impurities. To obtain pure copper, which can be used in electrical engineering, it is electrorefined. This method is based on electrolysis of an aqueous solution of copper salt with a soluble copper anode. Technical or blister copper, which serves as one of the electrodes, is immersed in a bath filled with an aqueous solution of copper sulfate. Another electrode is immersed in the bath. A direct current source is connected to the electrodes so that commercial copper becomes the anode (positive pole of the current source), and the other electrode becomes the cathode.

A very important area of application of copper is the production of copper alloys. With many metals, copper forms so-called solid solutions, which are similar to ordinary solutions in that in them the atoms of one component (metal) are evenly distributed among the atoms of another (Fig. 34). Most copper alloys are solid solutions. An alloy of copper known since ancient times, bronze contains 430% tin (usually 810%). It is interesting that bronze is superior in its hardness to pure copper and tin taken separately. Bronze is more fusible than copper. Bronze products from masters of Ancient Egypt, Greece, and China have survived to this day. In the Middle Ages, tools and many other products were cast from bronze. The famous Tsar Cannon (Fig. 35) and the Tsar Bell in the Moscow Kremlin are also cast from an alloy of copper and tin.

Nowadays, the use of copper products is widespread. In Central Asia they wear copper products and practically do not suffer from rheumatism. In Egypt and Syria, even children wear copper items. In France, hearing disorders are treated with copper. In the United States, copper bracelets are worn as remedies for arthritis. In Chinese medicine, copper disks are applied to active points. And in Nepal, copper is considered a sacred metal. Copper therapy (copper treatment) is one of the types of traditional medicine. As a child, on the advice of my grandmother, applying a copper penny to the bump, we reduced pain and inflammation, although the 5-kopeck coin issued in Soviet times had a low copper content. In copper therapy, products with a copper content of at least 99.9% are used. The simplest, most effective, aesthetically beautiful and practical means of medical therapy is a copper bracelet, approved and recommended by the Ministry of Health of the Russian Federation.