Zinc - a detailed description of the properties with a photo; daily requirement for the element; a description of the excess and deficiency of this substance in the body with symptoms. Zinc (Zn): all about the chemical element and its role in human life

One of the metals that were discovered a long time ago, but to this day have not lost their relevance in use due to their remarkable properties, is zinc. His physical and Chemical properties allow the material to be used in various branches of technology and everyday life. It also has a significant impact on human health.

A Brief History of the Element's Discovery

What is zinc, people knew even before our era. After all, it was then that they learned to use alloys containing this metal. The Egyptians used ores containing copper and zinc, alloyed them and obtained a very durable, oxidation-resistant material. Household items, dishes made of this material were found.

The name zinc is found in the writings of the physician Paracelsus in the 16th century AD. In the same period, the Chinese began to actively use the metal, casting coins from it. Gradually, knowledge about this substance and its good technical properties is transferred to Europe. Then in Germany, England also learned what zinc is and where it can be used.

Brass was one of the first and most famous alloys used since ancient times in Cyprus and later in Germany and other countries.

The name comes from the Latin zincum, but the etymology is not entirely clear. There are several versions.

1. From the German zinke, which translates as "point".
2. From Latin zincum meaning " white coating".
3. Persian "cheng", meaning stone.
4. Ancient German zinco, which translates as "plaque", "an eyesore".

The element received its current name only at the beginning of the 20th century. The significance of zinc ions in the human body also became known only relatively recently (XX century). Before that, no ailments were associated with this element.

However, it is known that already in ancient times, many peoples used soups from young lamb meat as a means of recovering from illness and for a speedy recovery. Today we can say that the effect was achieved due to zinc ions, which are quite a lot in this dish. He helped restore blood circulation, relieve fatigue and activated brain activity.

Zinc element: characteristic

This element is located in periodic system in the second group, the secondary subgroup. Serial number 30, Zinc mass - 65.37. The only and constant oxidation state is +2. The electronic configuration of the outer layer of the atom is 4s 2 .

In the table Zinc, Copper, Cadmium, Chromium, Manganese and many others are transition metals. These include all those in which electrons fill the outer and pre-outer d and f energy sublevels.

Zinc salts

Almost all salts that are not double and complex, that is, do not contain extraneous colored ions, are colorless. The most popular in terms of human use are the following.

1. Zinc chloride - ZnCL 2. Another name for the compound is soldering acid. Outwardly, it is a white crystals that absorb moisture from the air well. It is used to clean the surface of metals before soldering, to obtain fiber, in batteries, to impregnate wood before processing as a disinfectant.
2. zinc sulfide. White powder, rapidly turning yellow when heated. It has a high melting point, unlike pure metal. It is used in the production of luminescent compositions applied to screens, panels and other items. It is a semiconductor.
3. - a common poison used to get rid of gnawing animals (mice, rats).
4. Smithsonite, or zinc carbonate - ZnCO 3. Colorless crystalline compound, insoluble in water. It is used in petrochemical production, as well as in silk production reactions. It is a catalyst in organic synthesis, used as a fertilizer for soils.
5. Zinc acetate - (CH 3 COO) 2 Zn. Colorless crystals, readily soluble in all solvents of any nature. It finds wide application in both chemical and medical and Food Industry. Used to treat nosopharyngitis. Used as food additive E650 - freshens breath, prevents the appearance of plaque on the teeth when included in chewing gum. It is also used for etching dyes, wood preservation, plastics production and other organic syntheses. Almost everywhere it plays the role of an inhibitor.
6. Zinc iodide - white crystals used in radiography, as an electrolyte in batteries, as a dye for electron microstudies.
7. Black or dark green crystals that cannot be obtained by direct synthesis, since zinc does not react with nitrogen. Formed from metal ammonia. At high temperatures, it decomposes with the release of zinc, therefore it is used to obtain it.
8. Zinc nitrate. Colorless hygroscopic crystals. The use of zinc in this form is carried out in the textile and leather industries for staining fabrics.

Zinc alloys

As mentioned above, there is the most common zinc alloy - brass. It is he who has been known since ancient times and is actively used by people until now. What does he represent?

Brass is copper and zinc, which are harmoniously combined with several other metals, giving additional luster, strength and refractoriness to the alloy. Zinc in the composition as an alloying element, copper - as the main one. The color of the material is yellow, shiny, but in the open air in a humid environment it can turn black. The melting point is about 950 o C, it can vary depending on the zinc content (the more it is, the lower the temperature).

The material is well rolled into sheets, pipes, welded by contact. Has good specifications, therefore, the following elements are made from it:

1. Machine parts and various technical devices.
2. Sleeves and stamped products.
3. Nuts, bolts, pipes.
4. Fittings, bushings, anti-corrosion parts of various types of transport.
5. Watch details.

Most of the metal we are considering mined in the world goes precisely to the manufacture of this alloy.

Another type of intermetallic compound is zinc antimonide. Its formula is Zn 4 Sb 3. It is also an alloy that is used as a semiconductor in transistors, thermal imagers, and magnetoresistive devices.

Obviously, the use of zinc and its compounds is very wide and almost universal. This metal is as popular as copper and aluminum, silver and gold, manganese and iron. Its importance is especially great for technical purposes as an anticorrosive material. After all, it is zinc that covers various alloys and products to protect against this destructive natural process.

Biological role

What is zinc in terms of medicine and biology? Does it matter for the life of organisms and how big is it? It turns out that zinc ions simply must be present in living beings. Otherwise, the deficit will lead to the following consequences:

• anemia;
• decrease in insulin;
• allergies;
• weight loss and memory loss;
• fatigue;
• depression;
• visual impairment;
• irritability and others.

The main places of concentration of zinc ions in the human body are the liver and muscles. Also, it is this metal that is part of most enzymes (for example, carbonic anhydrase). Therefore, most catalysis reactions occur with the participation of zinc.

What exactly do ions do?

1. Participate in the synthesis of male hormones and seminal fluid.
2. Promotes the absorption of vitamin E.
3. Participate in the breakdown of alcohol molecules in the body.
4. They are direct participants in the synthesis of many hormones (insulin, growth hormone, testosterone and others).
5. Takes part in hematopoiesis and healing of damaged tissues.
6. Regulates secretion sebaceous glands, supports normal growth of hair and nails, promotes regeneration processes in the skin.
7. It has the ability to eliminate toxins from the body and strengthen the immune system.
8. Affects the formation of taste sensations, as well as smell.
9. It takes part in the processes of transcription, vitamin A metabolism, nucleic synthesis and decay.
10. It is a participant in all stages of cell growth and development, and also accompanies the process of gene expression.

All this once again proves how important this metal is. Its role in biological systems was clarified only in the 20th century. Many troubles and ailments in the past could have been avoided if people knew about the treatment with zinc-based drugs.

How can you maintain the right amount of this element in the body? The answer is obvious. You need to eat foods that contain zinc. The list can be long, so we will only indicate those in which the maximum number of the element in question is:

• nuts and seeds;
• legumes;
• meat;
• seafood, especially oysters;
• cereals and bread;
• milk products;
• greens, vegetables and fruits.

Human use

We have already generally indicated in which industries and areas of industry zinc is used. The price of this metal and its alloys is quite high. For example, a sheet of brass measuring 0.6 x 1.5 is approximately estimated at 260 rubles. And this is quite justified, because the quality of the material is quite high.

So, metallic zinc, that is, as a simple substance, is used:

• for coating against corrosion on iron and steel products;
• in batteries;
• printing houses;
• as a reducing agent and catalyst in organic syntheses;
• in metallurgy to isolate other metals from their solutions.

It is used not only for cosmetic purposes, which we have already mentioned, but also as a filler in the production of rubber, as a white pigment in paints.

We talked about where various zinc salts are used when considering these compounds. Obviously, in general, zinc and its substances are important and significant components in industry, medicine and other industries, without which many processes would be impossible or very difficult.

Chapter. Obtaining and properties of zinc.

Zinc — this is an element of a side subgroup of the second group, the fourth period of the periodic system of chemical elements of D. I. Mendeleev, with atomic number 30. It is denoted by the symbol Zn (lat. Zincum). simple substance zinc(CAS number: 7440-66-6) at normal conditions- brittle transitional bluish-white color (darkens in air, covered with a thin layer of zinc oxide).

Obtaining and properties of zinc

66 zinc minerals are known, in particular zincite, sphalerite, willemite, calamine, smithsonite, and franklinite. Most common mineral- sphalerite, or zinc blende. Main component mineral- zinc sulfide ZnS, and various impurities give this substance all kinds of colors. Due to the difficulty of identifying this mineral, it is called blende (ancient Greek σφαλερός - deceptive). Zinc blende is considered the primary mineral from which other minerals of element No. 30 were formed: smithsonite ZnCO3, zincite ZnO, calamine 2ZnO SiO2 H2O. In Altai, you can often find striped "chipmunk" ore - a mixture of zinc blende and brown spar. A piece of such ore from a distance really looks like a hidden striped animal.

The average content of zinc in the earth's crust is 8.3 10-3%, in the main igneous rocks it is slightly higher (1.3 10-2%) than in acidic (6 10-3%). Zinc is an energetic water migrant, especially characteristic of its migration in thermal waters along with lead. Zinc sulfides, which are of great industrial importance, precipitate from these waters. Zinc also migrates vigorously to surface and groundwater, the main precipitant for it is hydrogen sulfide, sorption by clays and other processes play a lesser role.

Zinc is an important biogenic element; living organisms contain an average of 5 10-4% zinc. But there are exceptions - the so-called hub organisms (for example, some violets).

Zinc deposits are known in Australia, Bolivia. In the Russian Federation, the largest producer of lead-zinc concentrates is OJSC MMC Dalpolimetall.

Zinc in nature as native metal does not occur. Zinc is mined from polymetallic ores containing 1-4% Zn in the form of sulfide, as well as Cu, Pb, Ag, Au, Cd, Bi. Ores are enriched by selective flotation, obtaining zinc concentrates (50-60% Zn) and simultaneously lead, copper, and sometimes also pyrite concentrates. Zinc concentrates are fired in fluidized bed furnaces, converting zinc sulfide into ZnO oxide; the resulting sulfur dioxide SO2 is used to produce sulfuric acid. Pure zinc from ZnO oxide is obtained in two ways. According to the pyrometallurgical (distillation) method, which has existed for a long time, the calcined concentrate is subjected to sintering to give grain size and gas permeability, and then reduced with coal or coke at 1200–1300 °C: ZnO + C = Zn + CO. The resulting pairs metal condense and pour into molds. At first, the reduction was carried out only in hand-operated fired clay retorts; later, vertical mechanized carborundum retorts began to be used, then - shaft and electric arc furnaces; from lead-zinc concentrates, zinc is obtained in shaft furnaces with blast. Productivity gradually increased, but zinc contained up to 3% impurities, including valuable cadmium. Distillation zinc is purified by segregation (that is, by settling liquid metal from iron and parts lead at 500 °C), reaching a purity of 98.7%. The sometimes more complex and expensive purification by distillation, which is sometimes used, gives a purity of 99.995% and allows you to extract cadmium.

The main method of obtaining zinc is electrolytic (hydrometallurgical). Calcined concentrates are treated with sulfuric acid; the resulting sulfate solution is purified from impurities (by precipitation with zinc dust) and subjected to electrolysis in baths tightly lined inside lead or vinyl. Zinc is deposited on aluminum cathodes, from which it is daily removed (stripped off) and melted in induction furnaces. Usually the purity of electrolytic zinc is 99.95%, the completeness of its extraction from the concentrate (taking into account waste processing) is 93-94%. Production wastes produce zinc sulfate, Pb, Cu, Cd, Au, Ag; sometimes also In, Ga, Ge, Tl.

AT pure form- a fairly ductile silvery-white metal. It has a hexagonal lattice with parameters a = 0.26649 nm, c = 0.49431 nm, space group P 63 / mmc, Z = 2. At room temperature, it is brittle, when the plate is bent, a crack is heard from the friction of crystallites (usually stronger than the “cry tin"). At 100–150 °C, zinc is plastic. Impurities, even minor ones, sharply increase the fragility of zinc. The intrinsic concentration of charge carriers in zinc is 13.1·1028 m−3.

Pure metallic zinc is used to recover precious metals mined by underground leaching (gold, silver). In addition, zinc is used to extract silver, gold (and other metals) from crude lead in the form of zinc intermetallic compounds with silver and gold(the so-called "silver foam"), then processed by conventional refining methods.

It is used to protect steel from corrosion (zinc coating of surfaces not subject to mechanical stress, or metallization - for bridges, tanks, metal structures).

Zinc is used as a material for the negative electrode in chemical current sources, that is, in batteries and accumulators, for example: manganese-zinc cell, silver-zinc battery (EMF 1.85 V, 150 W h / kg, 650 W h / dmi, low resistance and colossal discharge currents), mercury-zinc element (EMF 1.35 V, 135 W h / kg, 550-650 W h / dmi), dioxysulfate-mercury element, iodate-zinc element, copper- oxide galvanic cell (EMF 0.7–1.6 Volt, 84–127 Wh/kg, 410–570 Wh/dm³), chromium-zinc cell, zinc-silver chloride cell, nickel-zinc battery (EMF 1 .82 Volt, 95-118 Wh / kg, 230-295 Wh / dmi), lead-zinc cell, zinc-chlorine battery, zinc-bromine battery, etc.

Zinc (Zinc) is

The role of zinc in zinc-air batteries, which are characterized by a very high specific energy intensity, is very important. They are promising for starting engines (lead battery - 55 W h / kg, zinc-air - 220-300 W h / kg) and for electric vehicles (mileage up to 900 km).

Zinc is added to many brazing alloys to lower their melting point.

Zinc oxide is widely used in medicine as an antiseptic and anti-inflammatory agent. Zinc oxide is also used for the production of paint - zinc white.

Zinc is an important component of brass. Zinc alloys with aluminum and magnesium (ZAMAK, ZAMAK), due to their relatively high mechanical and very high casting qualities, are very widely used in engineering for precision casting. In particular, in the arms business, the bolts of pistols are sometimes cast from the ZAMAK (-3, -5) alloy, especially those designed for the use of weak or traumatic cartridges. Also, all kinds of technical fittings are cast from zinc alloys, such as car handles, carburetor bodies, scale models and all kinds of miniatures, as well as any other products that require precise casting with acceptable strength.

Zinc chloride is an important flux for soldering metals and a component in fiber production.

Zinc sulfide is used for the synthesis of temporary phosphors and various kinds of luminescents based on a mixture of ZnS and CdS. Phosphors based on zinc and cadmium sulfides are also used in the electronics industry for the manufacture of luminous flexible panels and screens as electroluminophors and compounds with a short glow time.

Telluride, selenide, phosphide, zinc sulfide are widely used semiconductors.

Zinc selenide is used to make optical glasses with very low absorption in the mid-infrared range, such as in carbon dioxide lasers.

The different uses of zinc account for:

galvanizing - 45-60%

medicine (zinc oxide as an antiseptic) - 10%

alloy production - 10%

production of rubber tires - 10%

oil paints - 10%.

World zinc production in 2009 amounted to 11.277 million tons, which is 3.2% less than in 2008.

List of countries by zinc production in 2006 (based on " Geological survey U.S.A")

essential for the production of sperm and male hormones

required for the metabolism of vitamin E.

important for the normal functioning of the prostate.

participates in the synthesis of various anabolic hormones in the body, including insulin, testosterone and growth hormone.

It is necessary for the breakdown of alcohol in the body, as it is part of alcohol dehydrogenase.

Zinc (Zinc) is

Among the foods consumed by humans, the highest content of zinc is in oysters. However, pumpkin seeds contain only 26% less zinc than oysters. For example, eating 45 grams of oysters will give you the same amount of zinc as 60 grams of pumpkin seeds. Almost all cereal grains contain zinc in sufficient quantities and in an easily digestible form. Therefore, the biological need of the human body for zinc is usually fully met by the daily consumption of whole grain products (unrefined grains).

~ 0.25 mg / kg - apples, oranges, lemons, figs, grapefruits, all fleshy fruits, green vegetables, mineral water.

~ 2-8 mg / kg - raspberries, black currant, dates, most vegetables, most marine fish, lean, milk, peeled rice, regular and sugar beets, asparagus, celery, tomatoes, potatoes, radish, bread.

~8-20 mg/kg - some grains, yeast, onions, garlic, brown rice, eggs.

~ 20-50 mg / kg - oat and barley flour, molasses, egg yolk, rabbits and chickens, nuts, peas, beans, lentils, green tea, dried yeast, squid.

~ 30-85 mg / kg - beef liver, some types of fish.

~ 130-202 mg / kg - wheat bran, germinated wheat grains, pumpkin seeds, sunflower seeds.

The lack of zinc in the body leads to a number of disorders. Among them, irritability, fatigue, memory loss, depressive states, decreased visual acuity, weight loss, accumulation of certain elements in the body ( gland, cuprum, cadmium, lead), decreased insulin levels, allergic diseases, anemia and others.

To assess the content of zinc in the body, its content in hair, serum and whole blood is determined.

With long-term intake in the body in large quantities, all zinc salts, especially sulfates and chlorides, can cause poisoning due to the toxicity of Zn2+ ions. 1 gram of zinc sulfate ZnSO4 is enough to cause severe poisoning. In everyday life, chlorides, sulfates and zinc oxide can be formed during storage food products in zinc and galvanized dishes.

Zinc (Zinc) is

ZnSO4 poisoning leads to anemia, growth retardation, infertility.

Zinc oxide poisoning occurs when its vapors are inhaled. It manifests itself in the appearance of a sweetish taste in the mouth, a decrease or complete loss of appetite, severe thirst. There is fatigue, a feeling of weakness, tightness and pressing pain in the chest, drowsiness, dry cough.

Areas of application of zinc. TsVOO For the production of chemically pure reagents for the needs of the electrical industry and for scientific purposes.

Central Military District For the needs of the printing and automotive industries industry.

CV For injection-molded critical parts, aircraft and auto appliances; for the manufacture of zinc oxide used in the chemical and pharmaceutical industry; for chemically pure reagents; to obtain zinc powder used in the battery industry.

Ts0A For zinc sheets used in the production of galvanic cells, for injection-molded critical parts of aircraft and auto appliances; for the manufacture of zinc alloys processed by pressure; for hot and galvanic galvanizing of trade items and semi-finished products; for the manufacture of zinc powder; for alloying aluminum alloys; for the manufacture of zinc white.

C0 For zinc sheets used in the production of galvanic cells; for injection-molded critical parts of aircraft and auto appliances; for the manufacture of zinc alloys for pressure treatment, for hot dip galvanizing and galvanizing trade items and semi-finished products, including on continuous galvanizing units; for the manufacture of muffle and furnace dry zinc white; for the manufacture of zinc powder; for alloying aluminum alloys.

Zinc (Zinc) is

C1 For the production of pressure-treated alloys (including zinc sheets); for the manufacture of galvanic cells (castings); for galvanic galvanizing in the form of anodes; for hot dip galvanizing trade items and semi-finished products, including on continuous galvanizing units; for the manufacture of muffle and furnace dry zinc white; for special brasses; copper-zinc alloys; for the preparation of flux when tinning tin for cans; for the manufacture of zinc powder used in the chemical and metallurgical industries.

C2 For the production of zinc sheets, for copper-zinc alloys and bronzes; for hot-dip galvanizing of trade items and semi-finished products; for the manufacture of wire for shopping; for the manufacture of zinc powder used in the chemical and metallurgical industries.

C3 For the production of zinc sheets, including those intended for the printing industry, for ordinary foundry and lead copper-zinc alloys; for hot-dip galvanizing of trade items and semi-finished products; for the manufacture of zinc powder used in the metallurgical industry.

Latin zincum translates as "white coating". Where this word came from is not exactly established. Some historians of science and linguists believe that it comes from the Persian "cheng", although this name does not refer to zinc, but to stones in general. Others associate it with the ancient German "zinco", meaning, in particular, an eyesore.

For many centuries of mankind's acquaintance with zinc, its name has repeatedly changed: "spelter", "tutia", "spiauter" ... The generally recognized name "zinc" became only in the 20s of our century.

Zinc (Zinc) is

In every business there is a champion: a champion in running, in boxing, in dancing, in speed cooking, in guessing crossword puzzles ... With the name of the Champion (Champion with capital letter) is connected with the history of the first zinc production in Europe. In the name of John Champion, it was issued for the distillation method for obtaining zinc from oxidized ores. This happened in 1739, and by 1743 a plant was built in Bristol with an annual production of 200 tons of zinc. After 19 years, the same D. Champion patented a method for obtaining zinc from sulfide ores.

According to ancient legends, the fern blooms only on the night of Ivan Kupala and this flower is guarded by evil spirits. In fact, the fern as a spore plant does not bloom at all, but the words "fern flowers" can be found on the pages of quite serious scientific journals. This is the name given to the characteristic patterns of zinc coatings. These patterns arise due to special additives of antimony (up to 0.3%) or tin(up to 0.5%), which are introduced into hot-dip galvanizing baths. At some factories, "flowers" are obtained differently - by pressing a hot galvanized sheet against a corrugated conveyor.

The world's first electric motor was designed by Academician B.S. Jacobi. In 1838 universal admiration called his electric ship - a boat with an electric engine, which transported up and down the Neva up to 14 passengers. The motor received current from galvanic batteries. In the chorus of enthusiastic responses, the opinion of the famous German chemist Justus Liebig sounded dissonant: “It is much more profitable to burn coal directly to obtain heat or work than to spend this coal for the extraction of zinc, and then by burning it in batteries to get work in electric motors. As a result, Liebig turned out to be half right: batteries soon ceased to be used as a power source for electric motors. They were replaced with batteries capable of replenishing energy reserves. Zinc has not been used in batteries until recently. Only in our days have batteries with electrodes made of silver and zinc. In particular, such a battery worked on board the third Soviet artificial Earth satellite.

In the prehistoric Dacian ruins in Transylvania, an idol was found cast from an alloy containing about 87% zinc. Obtaining metallic zinc from galmea (Zn4*H2O) was first described by Strabo (60-20 BC). Zinc in this period called tutia or fake silver.

One of the biggest scientific sensations of the 20s of our century is associated with crystalline zinc oxide. In 1924, one of the radio amateurs in the city of Tomsk set a record for receiving range.

With a detector receiver, he received transmissions from radio stations in France and Germany in Siberia, and the audibility was more distinct than that of the owners of single-tube receivers.

How could this happen? The fact is that the detector receiver of the Tomsk amateur was mounted according to the scheme of O.V. Losev, an employee of the Nizhny Novgorod radio laboratory.

The fact is that Losev included a crystal of zinc oxide in the scheme. This significantly improved the sensitivity of the device to weak signals. Here is what was said in the editorial of the American magazine "Radio-News", entirely devoted to work Nizhny Novgorod inventor: "O.V. Losev from the State Radioelectric Laboratory in Russian Federation makes an era, and now the crystal will replace the lamp!

Zinc is the only element that enters the human life cycle (unlike other metals used in protective coatings). The daily human requirement for zinc is estimated at 15 mg; in drinking water, a zinc concentration of 1 mg / l is allowed. It is very difficult to get poisoned with zinc, only when inhaling zinc fumes from welding, sensations can occur that indicate poisoning, which disappear when the victim is removed from this working atmosphere. "Foundry fever" is also observed in workers associated with the processing of substances containing zinc, if the concentration of zinc dust in the air at the workplace exceeds 15 mg/m3.

The history of galvanizing begins in 1742, when the French chemist Melouin, at a presentation at the French Royal Academy, described the method of coating gland by immersing it in molten zinc.

In 1836, Sorel, another French chemist, received patent on the method of coating iron with zinc after the first cleaning with 9% sulfuric acid and treatment with ammonium chloride. Like patent in England was issued in 1837. By 1850, in Britain 10,000 tons of zinc per year were used to protect steel from corrosion.

A revolutionary method of using hydrogen, obtained in an environmentally friendly and cheap way, was developed by a team of scientists from Israel, Sweden, Switzerland and France.

This method is based on the production of zinc powder. This will help to get rid of the use of gasoline, which pollutes the atmosphere, in the future. The recent energy boom has once again signaled the need to develop an alternative energy source for cars. One of the most likely replacement candidates gasoline considered to be hydrogen. Its reserves are large and it can be obtained from water. One of the problems that arise when using hydrogen is the high cost of its production and transportation. Electrolysis is currently the most widely used method for producing hydrogen. It splits water molecules into their constituents: hydrogen and oxygen by passing electricity. This one is relatively simple, but requires a lot of electricity. It is quite expensive to use on an industrial scale. The separation of water molecules by heating is not very common, as it requires temperatures above 2,500 degrees Celsius. A few years ago, a new method was developed using zinc powder to produce hydrogen. it process required a lower temperature - 350 degrees Celsius. Since zinc is a fairly common element and the fourth most produced element in the world after iron, aluminum and cuprum, it can easily be used to produce hydrogen. The only problem that may arise is the difficulty in obtaining zinc powder (Zn) from zinc oxide (ZnO) by electrolysis or in a melting furnace. However, these methods are very energy intensive and pollute environment. During the development, scientists used the world's strongest computer-controlled mirrors located at the Israeli Weitzman Institute. A group of mirrors is able to concentrate solar energy at the desired location, providing ultra-high temperatures. Thus, scientists were able to obtain zinc powder for the production of hydrogen.

The growing use of galvanized steel structures for outdoor construction, where long life is a must, requires a thicker zinc layer than usual.

Where a structure is expected to last longer than galvanizing can provide, consideration should be given to recoating the zinc layer with paint. Currently, there are paints that can be applied to freshly galvanized. Alternatively, staining can be carried out a little later, after the formation of an oxide film. A zinc coating under the paint is necessary to protect the iron or steel from corrosion if the paint layer fails in period between maintenance. It is very easy to remove the old layer of paint from a galvanized surface and repaint, but it is much more difficult to remove paint from a corroded surface if it was previously applied directly to steel or iron. The combination of galvanizing with subsequent painting ensures a long service life.

The production and consumption of zinc is associated with almost all areas of activity (construction, transport, energy, medicine, food, ceramics, etc.).

World consumption of zinc is constantly growing, regardless of the state of the world economy, and often outpacing the growth of the gross national product.

40-50% of world zinc consumption is used for the production of galvanized steel - with approximately 1/3 for hot dip galvanizing of finished trade items, 2/3 for galvanizing strip and wire.

It is impossible to imagine modern life without zinc. More than 10 million tons of zinc are consumed annually in the world. House, computer, many things around us - all this is made using zinc.

Millions of tons of zinc are produced annually in the world. Half of this volume is used to protect steel from rust. An environmentally attractive point in favor of the use of zinc is that 80% of it is reused and it does not lose its physical and chemical properties. Protecting steel against corrosion, zinc helps to save such as energy. By extending the life of steel, zinc extends the life cycle of goods and capital investments - houses, bridges, power and water distributors, telecommunications - thus protecting investments and helping to reduce repair and maintenance costs.

Due to its unique properties, zinc is used in many industries industry:

in construction;

for the production of tires and rubber trade items;

for money issue fertilizers and animal feed;

for the manufacture of automotive equipment and household appliances, accessories, tools;

for the manufacture of pharmaceutical, medical equipment and cosmetics.

Unlike artificial chemical compounds, zinc is a natural element. Zinc is present in water, air, soil, and also plays an important role in biological processes all living organisms, including humans, animals and plants.

Zinc compounds must also be present in human food. The human body contains 2-3 grams of zinc. The healing properties of zinc compounds have given impetus to their use in many pharmaceutical and cosmetic products, from sticky patches to antiseptic creams and sunscreen lotions.

The use of zinc meets the goals of the long-term development of mankind.

Zinc can be reused an infinite number of times without losing its physical and chemical properties. Today, about 36% of the world's zinc comes from recycling, and about 80% of recyclable zinc is actually recycled. Thanks to the long life cycle of most zinc products, which can sometimes last over 100 years without repair, much of the zinc produced in the past is still in use, constituting a valuable fortifying zinc source for future generations.

General characteristics of zinc Zn

daily requirement for zinc

The daily requirement for zinc is 10-15 mg.

Tolerable upper intake limit for zinc is set at 25 mg per day

The need for zinc increases with:

sports

profuse sweating.

Zinc is part of more than 200 enzymes that are involved in various metabolic reactions, including the synthesis and breakdown of carbohydrates, proteins, fats and nucleic acids- the main genetic material. It is an integral part of the pancreatic hormone - insulin, which regulates blood sugar levels.

Zinc contributes to the growth and development of a person, is necessary for puberty and the continuation of offspring. It plays an important role in the formation of the skeleton, is necessary for the functioning of the immune system, has antiviral and antitoxic properties, and is involved in the fight against infectious diseases and cancer.

Zinc is necessary to maintain the normal condition of hair, nails and skin, provides the ability to feel the taste, smell. It is part of the enzyme that oxidizes and neutralizes alcohol.

Zinc is characterized by considerable antioxidant activity (like selenium, vitamins C and E) - it is part of the superoxide dismutase enzyme, which prevents the formation of aggressive reactive oxygen species.

Signs of a zinc deficiency

loss of smell, taste and appetite

brittle nails and the appearance of white spots on the nails

hair loss

frequent infections

poor wound healing

late sexual content

impotence

fatigue, irritability

decreased ability to learn

Signs of excess zinc

gastrointestinal disorders

headache

Zinc is essential for the normal functioning of all body systems.

The earth is getting poorer in zinc, and the food we eat contains a lot of carbohydrates and few micronutrients, which further exacerbates the situation. Excess calcium in the body reduces the absorption of zinc by 50%. Zinc is quickly excreted from the body during stress (physical and emotional), under the influence of toxic metals, pesticides. With age, the assimilation of this mineral decreases significantly, so its additional intake is necessary.

Zinc supplements help prevent Alzheimer's disease. In people suffering from this disease, it is almost impossible to detect the zinc-dependent thymus hormone thymulin, which implies that zinc may play a role in the onset of the pathological process.

Zinc is vital for the functioning of the thymus and the normal functioning of the immune system. As a component of retinol-carrying protein, zinc, together with vitamin A and vitamin C, prevents the occurrence of immunodeficiencies by stimulating the synthesis of antibodies and exerting an antiviral effect. Malignant tumors develop more actively against the background of a reduced level of zinc.

The most important symptom of zinc deficiency is general nervousness and weakness. The symptoms of almost all skin diseases decrease or disappear with an increase in the zinc content in the body. It is especially effective in the treatment of acne, which some researchers consider a disease caused by a deficiency of zinc and one of the essential fatty acids.

The effects of dietary supplements containing zinc do not appear immediately, it can take weeks and months before results are noticeable on the skin.

Zinc plays an important role in the hormonal balance of the body. The male body needs more zinc than the female body. The development of prostate adenoma is inextricably linked with inadequate zinc intake throughout life. Lack of zinc can impair sperm formation and testosterone production. In a group of men over 60 who took zinc, serum testosterone levels literally doubled.

Zinc element(Zn) in the periodic table has serial number 30. It is in the fourth period of the second group. Atomic weight - 65.37. Distribution of electrons in layers 2-8-18-2.

30 element of the periodic table Zinc is a bluish-white metal that melts at 419 (C), and at 913 (C it turns into steam; its density is 7.14 g / cm3. At ordinary temperatures, zinc is rather brittle, but at 100-110 ( C it bends well and rolls into sheets. In air, zinc is covered with a thin layer of oxide or basic carbonate, which protects it from further oxidation. Water has almost no effect on zinc, although it is in the series of voltages much to the left of hydrogen. This is due to the fact that the resulting on the surface of zinc, when it interacts with water, the hydroxide is practically insoluble and prevents the further course of the reaction.In dilute acids, zinc dissolves easily with the formation of the corresponding salts.In addition, zinc, like beryllium and other metals that form amphoteric hydroxides, dissolves in alkalis.If you heat zinc in air to the boiling point, then its vapor ignites and burns with a greenish-white flame, forming zinc oxide.

The average content of zinc in the earth's crust is 8.3 10-3%, in the main igneous rocks it is slightly higher (1.3 10-2%) than in acidic (6 10-3%). Zinc is an energetic water migrant, especially characteristic of its migration in thermal waters along with lead. Zinc sulfides, which are of great industrial importance, precipitate from these waters. Zinc also migrates vigorously in surface and underground waters, the main precipitant for it is hydrogen sulfide, sorption by clays and other processes play a lesser role.
Zinc is an important biogenic element; living organisms contain an average of 5 10-4% zinc. But there are exceptions - the so-called hub organisms (for example, some violets).

Zinc deposits

Zinc deposits are known in Iran, Australia, Bolivia, Kazakhstan. In Russia, the largest producer of lead-zinc concentrates is OJSC MMC Dalpolimetall

Obtaining zinc

Zinc does not occur in nature as a native metal.
Zinc is mined from polymetallic ores containing 1-4% Zn in the form of sulfide, as well as Cu, Pb, Ag, Au, Cd, Bi. Ores are enriched by selective flotation, obtaining zinc concentrates (50-60% Zn) and simultaneously lead, copper, and sometimes also pyrite concentrates. Zinc concentrates are fired in fluidized bed furnaces, converting zinc sulfide into ZnO oxide; the resulting sulfur dioxide SO2 is used to produce sulfuric acid. Pure zinc from ZnO oxide is obtained in two ways. According to the pyrometallurgical (distillation) method, which has existed for a long time, the calcined concentrate is subjected to sintering to give grain size and gas permeability, and then reduced with coal or coke at 1200–1300 °C: ZnO + C = Zn + CO. The resulting metal vapors are condensed and poured into molds. At first, the reduction was carried out only in hand-operated fired clay retorts; later, vertical mechanized carborundum retorts began to be used, then - shaft and electric arc furnaces; from lead-zinc concentrates, zinc is obtained in shaft furnaces with blast. Productivity gradually increased, but zinc contained up to 3% impurities, including valuable cadmium. Distillation zinc is purified by segregation (that is, by settling the liquid metal from iron and part of lead at 500 ° C), reaching a purity of 98.7%. The sometimes more complex and expensive purification by rectification, which is sometimes used, gives a metal with a purity of 99.995% and allows the extraction of cadmium.

The main method of obtaining zinc is electrolytic (hydrometallurgical). Calcined concentrates are treated with sulfuric acid; the resulting sulfate solution is purified from impurities (by deposition with zinc dust) and subjected to electrolysis in baths tightly lined inside with lead or vinyl plastic. Zinc is deposited on aluminum cathodes, from which it is daily removed (stripped off) and melted in induction furnaces. Usually the purity of electrolytic zinc is 99.95%, the completeness of its extraction from the concentrate (taking into account waste processing) is 93-94%. Production wastes produce zinc sulfate, Pb, Cu, Cd, Au, Ag; sometimes also In, Ga, Ge, Tl.

Biological role

The body of an adult contains an average of about 2 g of zinc, which is concentrated mainly in the muscles, liver and pancreas. More than 400 enzymes contain zinc. Among them are enzymes that catalyze the hydrolysis of peptides, proteins and esters, the formation of aldehydes, and the polymerization of DNA and RNA. Zn2+ ions in the composition of enzymes cause polarization of water and organic molecules, facilitating their deprotonation according to the reaction:

Zn2+ + H2O = ZnOH+ + H+
The most studied enzyme is carbonic anhydrase, a protein containing zinc and consisting of approximately 260 amino acid residues. This enzyme is found in red blood cells and contributes to the conversion of carbon dioxide formed in the tissues during their life activity into bicarbonate ions and carbonic acid, which is carried by the blood to the lungs, where it is excreted from the body in the form of carbon dioxide. In the absence of the enzyme, the conversion of CO2 to the anion HCO3- proceeds at a very low rate. In the carbonic anhydrase molecule, the zinc atom is bonded to three imidazole groups of histidine amino acid residues and a water molecule, which is easily deprotonated, turning into a coordinated hydroxide. The carbon atom of the carbon dioxide molecule that contains the partial positive charge, interacts with the oxygen atom of the hydroxyl group. Thus, the coordinated CO2 molecule is converted into a bicarbonate anion, which leaves the active site of the enzyme, being replaced by a water molecule. The enzyme speeds up this hydrolysis reaction 10 million times.

Application of zinc

Pure metallic zinc is used to recover precious metals mined by underground leaching (gold, silver). In addition, zinc is used to extract silver, gold (and other metals) from crude lead in the form of zinc-silver-gold intermetallic compounds (the so-called “silver foam”), which are then processed by conventional refining methods.
It is used to protect steel from corrosion (zinc coating of surfaces not subject to mechanical stress, or metallization - for bridges, tanks, metal structures).
Zinc is used as a material for the negative electrode in chemical current sources, that is, in batteries and accumulators, for example: manganese-zinc cell, silver-zinc battery (EMF 1.85 V, 150 W h / kg, 650 W h / dm³, low resistance and colossal discharge currents), mercury-zinc element (EMF 1.35 V, 135 W h / kg, 550-650 W h / dm³), dioxysulfate-mercury element, iodate-zinc element, copper- oxide galvanic cell (EMF 0.7–1.6 Volt, 84–127 W h / kg, 410–570 W h / dm³), chromium-zinc cell, zinc-silver chloride cell, nickel-zinc battery (EMF 1 .82 Volt, 95-118 Wh / kg, 230-295 Wh / dm³), lead-zinc cell, zinc-chlorine battery, zinc-bromine battery, etc.

The role of zinc in zinc-air batteries, which are characterized by a very high specific energy intensity, is very important. They are promising for starting engines (lead battery - 55 W h / kg, zinc-air - 220-300 W h / kg) and for electric vehicles (mileage up to 900 km).

Zinc plates are widely used in printing, in particular, for printing illustrations in large-circulation publications. For this, zincography has been used since the 19th century - the manufacture of clichés on a zinc plate by etching the pattern in it with acid. Impurities, with the exception of a small amount of lead, impair the etching process. Before pickling, the zinc plate is annealed and hot rolled.
Zinc is added to many brazing alloys to lower their melting point.
Zinc oxide is widely used in medicine as an antiseptic and anti-inflammatory agent. Zinc oxide is also used for the production of paint - zinc white.

Zinc is an important component of brass. Zinc alloys with aluminum and magnesium (ZAMAK, ZAMAK), due to their relatively high mechanical and very high casting qualities, are very widely used in engineering for precision casting. In particular, in the arms industry, the bolts of pistols are sometimes cast from the ZAMAK (-3, -5) alloy, especially those designed for the use of weak or traumatic cartridges. Also, all kinds of technical fittings are cast from zinc alloys, such as car handles, carburetor bodies, scale models and all kinds of miniatures, as well as any other products that require precision casting with acceptable strength.

zinc chloride- an important flux for soldering metals and a component in the production of fibers.
Zinc sulfide is used in the manufacture of short afterglow phosphors and other luminescent compounds, usually mixtures of ZnS and CdS activated with other metal ions. Phosphors based on zinc and cadmium sulfides are also used in the electronics industry for the manufacture of luminous flexible panels and screens as electroluminophors and compounds with a short glow time.
Telluride, selenide, phosphide, zinc sulfide are widely used semiconductors. Zinc sulfide - component many phosphors. Zinc phosphide is used as a rodent poison.
Zinc selenide is used to make optical glasses with very low absorption in the mid-infrared range, such as in carbon dioxide lasers.

The different uses of zinc account for:

galvanizing - 45-60%
medicine (zinc oxide as an antiseptic) - 10%
alloy production - 10%
production of rubber tires - 10%
oil paints - 10%

Zinc has long established itself as an important chemical element. Even before our era, people knew a lot about it and widely used it in various fields. The properties of this material allow the use of zinc in many industries and in everyday life. The material has been successfully used in chemical industry, in mechanical engineering and in construction. Therefore, today we will look at beneficial features and characteristics of zinc metal and alloys based on it, the price per kg, features of use, as well as the manufacture of the material.

Concept and features

To begin with, you are invited to general characteristics zinc. This product is not only a necessary production metal, but also an important biological element. In any living organism, it is present up to 4% of all elements. The richest zinc deposits are Bolivia, Iran, Kazakhstan and Australia. In our country, one of the largest manufacturers is considered to be the enterprise OJSC MMC Dalpolimetall.

If we consider zinc from the side of the periodic system of Mendeleev, then it belongs to transition metals and has the following characteristics:

• Sequence number: 30
• Weight: 65.37.
• The oxidation state is +2.
• Colour: bluish white.

Zinc is a radioactive isotope with a half-life of 244 days.

If we consider zinc from the side of a simple substance, then this material has the following characteristics:

• Type of material - metal.
• Color - silver-blue.
• Coating - protected by an oxide film, under which shine and radiance are hidden.

Zinc is found in the earth's crust. The share of metal in it is not very large: only 0.0076%.

As a single material, zinc does not exist. It is a constituent of many ores and minerals.

• The most common are: zinc blende, cleophane, marmatite. In addition, zinc can be found in the following natural materials: wurtzite, franklenite, zincite, smithsonite, calamine, willemite.
• Companions of zinc are usually: germanium, cadmium, thallium, gallium, indium, cadmium.
• The most popular are alloys of zinc and aluminum, copper,.

The role of zinc in our lives will be told by a specialist in this video:

Competing metals

Only 4 metals can compete with zinc: titanium, aluminum, chromium and copper. The described materials have the following characteristics:

1. Aluminum: Silvery white color, good electrical and heat conductor, workable by pressure, corrosion resistant, low density, used in steel making process (to improve heat resistance).
2. Titanium: silver-white color, high melting point, oxidizes when exposed to air, low thermal conductivity, easy forging and stamping, at high temperature a strong protective film is formed on the surface.
3. Chromium: bluish-shiny color, high hardness, brittleness, resistance to oxidation in atmospheric and water conditions, used for decorative coating.
4. : red metal, has high ductility, good electrical conductivity, high thermal conductivity, resistance to corrosion processes, used in roofing materials.

For construction purposes, other non-ferrous metals are most often used (except zinc). These include:, silumin, babbitt, duralumin and several others.

Zinc differs from other metals in that it is easily deformable at temperatures from 100 ºС to 150 ºС. In this temperature range, zinc can also be forged and rolled into thin sheets.

Pros and cons

Pros:

• Good fluidity, making molds easy to fill.
• High ductility during rolling.
• Pure zinc lends itself well to forging.
• Due to its properties and the effect of temperature, it is able to take on various states.
• It perfectly protects the product from corrosion, due to which it is readily in demand in construction and mechanical engineering.

• May explode when heated together with phosphorus or sulfur.
• In the air it loses its luster.
• It has little plasticity at room temperature.
• Not found in nature in its pure form.

Weight, mechanical, chemical and physical properties of zinc, its main characteristics will be discussed below.

Properties and characteristics

So what are the properties of zinc?

Physical

Physical properties:

• It is a medium hard metal.
• Zinc has no polymorphic modifications.
• Cold zinc becomes a brittle metal.
• Acquires plasticity at a temperature of 100-100 ºС.
• At a higher temperature of 250 ºС, it again turns into a brittle metal.
• The melting point of solid zinc is 419.5 ºС.
• The transition temperature to steam is 913ºС.
• The boiling point is 906 ºС.
• The density of zinc in the solid state is 7.133 g / cm 3, in the liquid - 6.66 g / cm 3.
• Relative elongation 40-50%.
• Easily soluble in acids.
• Easily soluble in alkalis.

For information on how to melt zinc, see the video:

Chemical

Chemical properties of zinc:

• 3d 10 4s 2 is the configuration of the atom.
• Zinc is considered an active metal.
• It is an energy restorer.
• Electrode potential: -0.76 V.
• At temperatures below 100 ºС, it loses its luster and has a film coating.
• In humid air(especially if it has carbon dioxide) the metal is destroyed.
• During intense heating, zinc burns violently to form a bluish flame.
• Oxidation degree: .
• Acids and alkalis act differently on zinc, depending on the presence of various impurities in the metal.
• When zinc is heated in water, hydrolysis occurs with the formation of a white precipitate.
• Mineral acids of great strength can easily dissolve zinc.

Structure and composition

The zinc formula is as follows: Zn. The configuration of the outer layer of the atom is 4s 2 . Zinc has a metallic chemical bond, the crystal lattice is hexagonal, dense.

Zinc in nature consists of three stable isotopes (we list them: 64 Zn (48.6%), 66 Zn (26.9%) and 67 Zn (4.1%)) and several radioactive ones. The most important of the radioactive ones has a half-life of 244 days.

Production

As mentioned, zinc is not found in nature in its pure form. It is mainly obtained from polymeric ores. In these ores zinc is present in the form of sulfide. It always comes with the accompanying metals listed above.

A zinc concentrate is obtained using a selective flotation beneficiation process. Parallel to this process, other concentrates of substances come out of polymetallic ores. For example, and copper.

The resulting zinc concentrates are fired in a kiln. As a result of the action of high temperatures, zinc passes from the sulfide state to the oxide state. During the production process, sulfur dioxide is released, which goes to the production of sulfuric acid. from zinc oxide in two ways: pyrometallurgical and electrolytic.

• pyrometallurgical method has a very long history. The concentrate is calcined and subjected to a sintering process. The zinc is then reduced using coal or coke. Zinc obtained in this way is brought to a pure state by settling.
• At electrolytic way zinc concentrate is treated with sulfuric acid. The result is a solution that is subjected to an electrolysis process. Here the zinc is deposited and melted in special furnaces.

Areas of use

Zinc, as an element, is contained in sufficient quantities in the earth's crust and in water resources.

Zinc is also used in powder form for a number of chemical and technological processes.

This video will tell you how to remove zinc:

Zinc is the youngest of the heavy non-ferrous metals, and if at the beginning of the 19th century. its production did not exceed 900 tons per year, then at present zinc production is only in foreign countries is about 6 million tons per year.

Zinc occupies a special place among the metals used in industry. As a structural material, unalloyed zinc has not found wide application, since it has an insufficiently favorable set of mechanical, physical, and technological properties. However, additional doping of zinc various elements significantly improves the above properties and characteristics. Therefore, a significant part of zinc (up to 20%) goes to the preparation of zinc alloys, in which the main alloying components are aluminum and copper; zinc is also widely used for the production of copper alloys (brass).

Depending on the grade, zinc is used for galvanizing steel, producing zinc alloys, manufacturing zinc semi-finished products, and also for producing zinc compounds.

Approximately 30% of zinc rolled products are general-purpose zinc sheets, which are divided into four groups according to thickness: 0.15-0.4 mm; 0.5-0.9 mm; 1.0-1.2 mm; 1.5 mm or more. Zinc sheets are used in the manufacture of chemical current sources, galvanized dishes, etc. Printing plates for rotary machines in the printing industry are made from zinc sheets. Zinc anodes are used for galvanizing parts by galvanizing. A large amount of zinc sheets is used in construction for roofing, for the manufacture of pipes, gutters.

Zinc is most widely used as a coating to prevent corrosion of iron and alloys based on it (steels). For this purpose, up to 50% of the zinc produced by the industry is consumed. Galvanizing - the application of zinc or its alloys to the surface of a metal product - is used to protect steel sheets, wire, tape, fasteners, machine and instrument parts, fittings and pipelines from corrosion.

Initially, zinc coating was obtained by immersing a part in molten zinc, the so-called hot method, which for large-sized products, such as pipelines, has not lost its significance at the present time. To obtain thin zinc coatings, electrolytic galvanizing of parts is most often used. Both considered methods are feasible only in workshop conditions. To improve the protective properties of zinc coatings and extend their service life, the surface of the coatings is additionally passivated (phosphated, chromated), oiled or painted. Based on the high protective properties of zinc coatings, work has been done aimed at creating methods for applying them not in workshop conditions, but at the facility without dismantling the products. Gas-thermal and other spraying methods were created. But although their use made it possible to dramatically improve the properties of coatings, the problem of simplifying the deposition of coatings remained not completely resolved in the operating conditions of metal structures and products. In this regard, it was of interest to create methods for applying zinc coatings, which, in their simplicity and accessibility, do not differ from the methods for applying paints and varnishes.

Zinc-polymer and zinc-silicate materials have been developed and widely used, the zinc content of which is from 80 to 98%. Such zinc-containing materials are applied to structures to be protected using paint sprayers. The obtained coatings have higher insulating properties than metal zinc coatings, increase the reliability of protection of structures against corrosion and allow expanding the scope of zinc and its alloys for non-structural purposes. It should be noted that zinc-rich coatings can be used to restore damaged areas of metal coatings directly on metal structures and products without dismantling them.

Zinc coatings are widely used for various metal structures and products operated under the corrosive action of natural media - the atmosphere, sea, river, lake, reservoir, bottom water, soil, as well as neutral and slightly alkaline aqueous solutions. Depending on the properties of the corrosive environment and the composition of metal coatings, either protection against corrosion is carried out by isolating the surface, or the protective effect of coatings is manifested when they are violated. Zinc-rich coatings have made it possible to spread the use of zinc for large-sized structures, for example, stationary offshore structures, tanks and cisterns of ships, floating and stationary offshore platforms, building structures, long pipelines and communications and many other metal structures and products.

One of the main industries that consume galvanized sheet is the construction industry: up to 65% of all galvanized metal is spent on construction needs. The automotive industry is a major consumer of galvanized steel. The advantage of using galvanized sheets in the automotive and other industries is that favorable conditions are created for the comprehensive protection of steel from corrosion when a paint layer is applied to the metal coating. Zinc coating is an ideal base for painting, since the basic zinc carbonate formed in the pores differs little from zinc in volume and therefore does not cause destruction of the paint layer.

At automobile plants, bottoms, gas tanks, trunk lids, wheel covers, doors, mufflers, etc. are made from galvanized strips and sheets.

The per capita consumption of galvanized sheets in 1960 was 15.6 kg in the USA, 7.7 kg in Japan, 4.0 kg in England, 3.2 kg in France, and 2.3 kg in the FRG. By 1985, the consumption of this type of product should increase by more than 3 times.

Zinc is widely used in the form of various compounds. Some zinc compounds serve as paints, such as zinc oxide (zinc white), lithopone (a mixture of barium sulfate and zinc sulfide). Paint made from zinc sulfide has proven to be the best paint for spacecraft, as it has the best reflective properties. Zinc sulfide has a very important property, flashing under the action of a-, b- and y-rays, which allows it to be used to detect all types of radiation. Zinc sulfide alloyed with copper and silver has luminescent properties and, mixed with cadmium sulfide, is widely used for the manufacture of television tubes and screens.

Zinc sulfate and chloride are used in medicine as antiseptics. Anhydrous zinc chloride is often used as a dehydrating agent in a variety of condensation reactions in organic chemistry; it is widely used in the production of organic dyes, calico printing, and wood impregnation. Double salt - ammonium zinc chloride (NH 4) 2 ZnCl 2 - is used for soldering purposes. Zinc oxide is widely used in the production of rubber. It improves the quality of rubber tires and a number of other rubber products.

In the United States, in recent years, zinc has been widely used as a coating for launch structures for launching rockets. A huge amount of heat released during the combustion of fuel in a rocket is partially absorbed by the evaporation of the zinc coating, which protects the metal parts of the launch structures from destruction. Zinc is used in the so-called stabilizing devices, which correct the deviations of satellites when moving in space. Zinc compounds are widely used as energy sources in spaceships(zinc-silver oxide batteries).

Recently, zinc has received well-deserved recognition as the basis of a tread material used in electrochemical protection systems for ship hull structures, oil tanks, ship systems, apparatus and other metal structures.

The main purpose of zinc is to obtain zinc alloys, zinc alloys in the foundry are widely used for the manufacture of castings by injection molding.

Zinc alloys are smelted in flame and electric crucible furnaces and induction furnaces of industrial frequency with an iron core. The charge is prepared from fresh metals, remelted waste (up to 60-70%) of known chemical composition and ligatures (aluminum - copper, aluminum - magnesium and copper - aluminum).

The smelting of zinc alloys is carried out in the following sequence: the furnace heated to 400 ° C is loaded with remelted waste, ligatures, zinc and well-calcined charcoal is poured. After melting, the metal is thoroughly mixed and, if necessary, the rest of the zinc is loaded. The temperature during melting should not exceed 480 ° C. After complete melting, the metal is mixed again and poured into molds at a temperature of 400-460 ° C.

Along with the well-known areas and scales of use of unalloyed zinc, zinc-based alloys are also widely used in various sectors of the national economy as both a structural material and a non-structural one.

As a structural material, zinc alloys are mainly used: in instrument making, in the printing industry, in aviation industry, in the automotive industry, in shipbuilding, for the manufacture of household items.

As a non-structural material, zinc alloys are used: for casting anode protectors, for the manufacture of solders in the production of bearings and galvanic elements, as coatings for steel sheets.

Products received different ways casting and deformation, are widely used in instrument making, shipbuilding, aviation, automotive and other industries. The successful use of zinc alloys for structural and non-structural purposes is due to their physicochemical, technological and operational properties. Thus, the low melting point and high casting properties of zinc alloys make it possible, when casting under pressure and into a mold, to obtain high-strength castings with a good quality surface that practically does not require additional processing. Due to these properties, the share of castings from zinc alloys in the total volume of castings obtained by injection molding is quite high. For example, in the automotive industry, cast zinc alloys are used for casting carburettor bodies, pumps, speedometer frames, radiator grilles, various decorative parts, etc.

Zinc alloys are also used for casting parts. washing machines, vacuum cleaners, kitchen equipment, office machines, electric clock cases, printing machines, cash registers, beverage mixers, etc. To protect against corrosion, the surface of zinc castings is applied protective coatings(paints, enamels, plastics). Electrolytic coatings with copper, nickel and chromium have a good protective effect. Semi-finished products from wrought zinc alloys are quite easily subjected to pressing, rolling and stamping.

Zinc polished sheets are used in the printing industry for the manufacture of printing plates (cliches) by single etching.

The paper notes that the use of zinc-aluminum alloys in production is more cost-effective than aluminum alloys and brass. These alloys, having high hardness, have found wide application for the manufacture of parts operating under abrasive wear conditions. Due to the fact that alloys do not produce sparks, they can be used in flammable industries (pulleys, sprockets in mine hoists, etc.). In addition, alloys can be used in industries where there are gasoline vapors, i.e. with increased fire hazard. These alloys can also work in bearings, replacing brass and bronze.

The paper presents data on the use of zinc alloys to obtain high-precision parts of stable quality with a thin relief. With the transition to the production of zinc casting valve parts of a gas burner, which were previously machined from brass, the cost of products decreased by 6 times. It is also noted here that the use of zinc castings for radio industry products instead of plastic parts provides better thread quality, increases the strength and rigidity of products, and also makes it possible to ground products in radio equipment.

Zinc alloys are successfully replacing alloys of cast iron, malleable iron, bronze and some aluminum alloys.

A special place is occupied by zinc tread alloys. At present, they are indispensable for a number of complex and expensive structures in almost all developed countries. Due to their distinctive properties that other protector materials (magnesium, aluminum, manganese-based alloys) do not have, zinc protector alloys are used as protectors for corrosion protection in marine, bottom, reservoir and other natural environments of the inner surface of explosion-hazardous premises - tankers and tanks of oil tankers, fuel and ballast tanks of ships of all purposes, oil tanks, ship pipelines and systems, main underground oil and gas pipelines, limited volumes and cavities, various sealed volumes where hydrogen accumulation is not allowed, and other structures.

With a variety of operating conditions for protectors, the electrochemical characteristics of zinc alloys are determined by the value of the anode current density (Fig. 41), and in the overwhelming majority of cases, operating modes are 1-4 A/m 2 (shaded areas in Fig. 41), at which the alloys have high and stable values ​​of potential and current output.

Regardless of the patterns of change in the properties of zinc alloys (see Fig. 41), for their practical application, protector designs with a given service life and the necessary protective action zone are needed. These data are sufficient for the design and implementation of tread protection. These questions are of independent importance and are fairly well covered in the literature. Therefore, only the data necessary for the competent use of protectors made of zinc alloys are of interest.

Despite the current trend towards a decrease in the output of zinc alloy castings, their output is predicted to increase in the future due to the advantages of these alloys in obtaining particularly thin-walled castings and the possibility of applying good galvanic coatings.

Administration Overall rating of the article: Published: 2012.08.15