Properties of aluminum. Aluminum metal mining methods, application
Aluminum is one of the most common metals in the earth's crust. It has a silver-white color, light weight and high electrical conductivity. Metal melts at a temperature of 660 °C. Among the advantages are low density, fairly high strength, excellent heat conductivity, and corrosion resistance. Due to this, it is considered one of the most important technical metals. Aluminum alloys are produced by casting, deformation and other methods.
Historical facts
This metal was first mentioned during the time of the Roman Emperor Tiberius. It is not known whether this is a myth or truth, but the ruler was given a cup made of a very light metal, visually similar to silver, as a gift.
Fearing that the new material would devalue the gold and silver in the treasury, he executed the inventor and destroyed the aluminum works. They started talking about the light silver metal again after one and a half thousand years.
The famous German doctor and tester Paracelsus von Hohenheim discovered aluminum while studying alum earth. At that time it was called alumina.
Being in nature
Aluminum is considered one of the most common metals. It occupies 8.8% of the total mass of the earth's crust. Its compounds are bauxite, aluminosilicates, corundum. Most of the earth's crust consists of aluminosilicates. Bauxite is a rock from which aluminum is mined.
Almost all aluminum metal is found in nature only in compounds. In rare cases, pure aluminum metal is found in very small quantities. Among the main connections it is worth noting the following:
- Bauxite;
- Nephelines;
- Alunites;
- Alumina;
- Corundum;
- Feldspars;
- Kaolinite;
- Beryl;
- Chrysoberyl.
It is also found in natural waters in the form of low-toxic compounds such as fluoride. Pure aluminum contains only the stable isotope 27AI.
How is aluminum obtained?
The chemical element aluminum is quite difficult to obtain in its pure form. To obtain aluminum, you will need to carry out many steps to separate it from other elements.
How is aluminum obtained? The process itself consists of several stages: grinding bauxite ore and extracting alumina, obtaining the final element from it. In other words, it is called crystalline alumina, which is electrolyzed in cryolite. Melting point 960 - 970 °C.
This procedure requires a large amount of electricity, so the production of the substance is often located near large-scale power plants.
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Physical and chemical properties
The main physical properties of aluminum are high thermal conductivity, almost twice as much as steel. In addition, it has a density three times less than that of iron and zinc. And to all this it is worth adding the high strength of the material. Aluminum reacts with the following substances: copper, magnesium, silicon and others.
Chemical properties of aluminum:
- Formation of ionic and covalent compounds;
- High ionization energy;
- High charge density along with cations of other similar materials;
- Low susceptibility to corrosion;
- Reaction with oxygen, halogens, non-metals, fluorine, sulfur, nitrogen, carbon, water.
Where and how is aluminum produced?
Aluminum mining and production generally consists of three stages. The first and second stages are the production of bauxite and the formation of alumina from them. At the latter, pure material is obtained from alumina through the process of electrolysis. For 4-5 tons of aluminum-containing ore there are 2 alumina and 1 aluminum.
Aluminum can be mined from other aluminum ores around the world, but bauxite is considered the most common. Their basis is aluminum oxide and other minerals. Quality is determined by the high metal content. The total world reserve of aluminum ores is more than 18 billion tons. Considering the current production of aluminum in the world by country, it should be enough for more than one century.
Most of the bauxite is found in tropical countries. Only 73% comes from India, Guinea and Australia. Most bauxite is concentrated in Guinea. They are of high quality and have a minimum of mineral impurities. According to 2014 estimates, the following countries are the leaders in aluminum production: China, Australia, Brazil, Guinea, India, Jamaica, Russia and Kazakhstan.
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As a rule, aluminum mining is carried out using the open-pit method. Using special equipment, a layer of the earth's crust is removed, which is transported for the next stage of processing. There are deep ore mining points. To get it you have to build mines. The deepest mine is located in Russia. Its depth is 1550 meters.
Russia is in 7th place in the world ranking in aluminum production. There are more than fifty deposits in this country. Radynskoye, located in the Leningrad region, is considered one of the oldest.
Among all the aluminum mining sites in Russia, “Little Red Riding Hood”, Kalinskoye, Novo-Kalinskoye in Severouralsk, Cheremuzovskoye in the Sverdlovsk region are distinguished. Our country is also famous for its wide variety of metal manufacturing plants.
The largest in Russia and not only is Rusal, which produces more than 3 million tons of metal.
This metal has the following features:
- Its compounds exist not only on our planet, but also on the Moon and Mars;
- The human body contains more than 100 mg of this substance;
- The daily need for it is 2.4 mg;
- Most of the chemical element is found in apples;
- The first pure metal ingot was produced in 1932.
Areas of application of metal
Aluminum is widely used as a structural material. Its main advantages are light weight, stamping flexibility, corrosion resistance, high level of thermal or electrical conductivity, and non-toxic compounds. It is these advantages that have led to its widespread use in the production of kitchen utensils, packaging containers and foil for the food industry.
Speaking about the disadvantages, we should first of all note the low strength. Therefore, they began to add a small proportion of copper and magnesium to aluminum. The material is also successfully used in the production of electrical equipment, since its electrical conductivity is high. The only negative is the difficulty of soldering due to the strong oxide film.
Uranium ore: properties, application, mining
Light metal is used in various types of transport. In the aviation industry, it is the main structural material. The use of aluminum has also affected the shipbuilding industry. Using alloys, it is used to produce hulls, decks and equipment for ships.
Application as a reducing agent
Aluminum has been successfully used as a reducing agent. Aluminum metal restoration is quite common. Aluminum smelting makes it possible to restore rare types of metals. It is also used for pyrotechnics.
Types of alloys
The production of structural materials requires great strength. Aluminum does not have this, so it is combined with other chemical elements in smaller quantities. The most common alloys:
- Aluminum-magnesium. They are characterized by high strength, flexibility, corrosion resistance, vibration resistance and weldability. The percentage of magnesium in alloys is no more than 6%.
- Aluminum-manganese. They also have high strength, ductility, resistance to corrosion and weldability.
- Aluminum-copper. Some of the most high-tech. An improved version of low carbon steels. A significant disadvantage is susceptibility to corrosion.
Aluminum in jewelry
The metal was of particular value during the time of Napoleon III. At that time, jewelry, buttons, and dishes were made from it. It was evaluated along with gold and silver. But the demand for aluminum jewelry quickly faded as new mining opportunities emerged.
Other Applications
Aluminum sculpture
Light metal is used in various industries, including the military industry. This usually applies to weapons production. Its use in rocket technology as solid fuel and combustible components is also known.
Metal toxicity
Although aluminum is very common in the world, living things do not use it due to its low toxicity. Its compounds have had a harmful effect on people and animals for a long time. The greatest influence is exerted by aluminum acetate and hydroxide. They negatively affect the nervous system and excretory function of the body.
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Aluminum in investments
Currently, it is profitable to invest money in aluminum. The dynamics of aluminum prices in 2018 fluctuates up to $2,562 per ton. This growth is due to many sanctions and their consequences. Metal prices on the stock exchange in April-May did not reach above $2,280.
Source: https://promdevelop.ru/alyuminij-svojstva-kak-dobyvayut-sfery-primeneniya-i-investitsionnaya-privlekatelnost-na-2018-god/
Aluminum production from raw materials to technology
Aluminum is one of the most common chemical elements on Earth, used in mechanical engineering, energy and construction. Every year the extraction and consumption of this metal increases by 7%. Aluminum production is a complex technical process and requires a large amount of energy, transport, labor and raw materials.
Aluminum production in Russia and the world
Aluminum production volume in 2019 is 72 million tons. The international aluminum market is in deficit of 277 thousand tons. The largest producing countries of this metal are China, Russia, the USA, Australia, Brazil and India. Countries in North and South America are actively reducing bauxite production.
The growth in pure aluminum production is driven by countries in the Middle East and Asia. These regions contain over 73% of the world's reserves of aluminum ores lying on the earth's surface. They lack a large number of metallic and gaseous substances.
The largest aluminum producers in the world are the following transnational companies:
- UCRUSAL: Russian concern producing 13% of all aluminum alloys in the world. The company's production volume is 3.75 million tons per year. RUSAL has its own engineering and technical base and exports its products to Europe, North America and Southeast Asia.
- Chalco: A Chinese state-owned corporation, it is the second largest producer of aluminum materials in the world. The production volume is 3.4 million tons per year.
- RioTinto: Australian-British mining and metals company producing alumina. The concern's production volume is 3.1 million tons per year. RioTinto forms a joint venture with the Canadian organization Alcan to mine bauxite.
There is an oversupply of capacity in the market of the leading countries in the production of pure aluminum. This is due to the cyclical nature of demand and a large number of competitive enterprises. To reduce overcapacity, many enterprises began to export aluminum semi-finished products. Since 2015, sales of these products have grown by 20% annually.
There are 17 plants producing alumina and aluminum sheets in the Russian Federation. Most of the enterprises are located in the Urals and Siberia. The high efficiency of Russian aluminum smelters is determined by the following production location factors:
- Raw materials: enterprises are located near the main aluminum deposits. This allows you to reduce the cost of transporting raw materials and reduce the cost of finished products
- Energy: Pure aluminum is produced through electrolysis, so the plants are located near large hydroelectric power plants that generate large amounts of electrical energy.
- Consumer factor: the products of Russian aluminum producing companies are purchased by countries in South and North America, Asia, the Middle East, Europe and Africa.
- Transport: factories are located near major transport hubs, allowing for efficient transportation of raw materials and finished products over long distances. Railroad trains are most often used to transport metal.
Currently, aluminum production in Russia is declining and amounts to 7.3 million tons per year. This is due to the destruction of intersectoral and economic ties with the countries of the former USSR.
Production technology
Aluminum production technology includes 3 main stages:
- Bauxite mining.
- Processing of aluminum-containing ores into alumina.
- Isolation of pure metal from alumina through electrolysis and its purification from excess impurities.
The production of this chemical element is carried out in the electrolysis workshop. It consists of several buildings with a length of 1000 m. It contains electrolysis baths with large wires connected to a power source. The baths are equipped with electrodes energized at 6 V.
Most of the processes in the electrolysis shop are automated. Before electrolysis begins, the tank capacity is filled with molten cryolite. This substance is intended to create a conductive environment at high temperatures. The bottom of the bath acts as a cathode. The anode is carbon blocks immersed in cryolite.
In industry, aluminum is produced by the method of pyrometallurgy, developed by the German chemist Carl Joseph Bayer. This method is the reduction of metal using carbon dioxide or carbon monoxide.
All work at the enterprise is carried out in accordance with aluminum production schemes, which detail the process of alumina electrolysis. Initially, a portion of alumina is loaded into the bath. When exposed to electricity, the substance decomposes.
As a result, the bond between the aluminum and oxygen particles is broken.
After electrolysis, pure aluminum remains in the molten state at the bottom of the electrolytic bath. Oxygen reacts with carbon to form carbon dioxide. The resulting material is poured into vacuum ladles and delivered to the foundry. Here the metal is subjected to heat treatment. By remelting, excess impurities are removed from the alloy. As a result, the substance takes on a solid form and is sorted into blocks weighing up to 22 kg.
Aluminum retains its properties during long-term use. Therefore, some aluminum products are recycled and reused to create pure metals, which has a positive impact on the environment.
The volume of environmental protection costs in this industry is 4%.
The authorities use many economic measures in the field of environmental protection, providing benefits to entrepreneurs who comply with environmental regulations and government standards in the process of economic activity.
Alumina production
Alumina is a white powder formed by the reaction of aluminum with oxygen. The technological process for the production of this substance was developed by Bayer at the end of the 19th century. This technology produces 90% of the world's alumina.
When producing powdered aluminum oxide using the Bayer method, high-quality bauxite with a low content of impurities can be used. During the alumina production process, crystalline aluminum hydroxide is dissolved in high concentration caustic alkali.
The chemical reaction takes place at high temperatures. Foreign substances included in bauxite, when interacting with a solution of caustic soda, precipitate. The impurities separated from the aluminum hydroxide are called red mud.
During processing, compounds of silicon, iron, titanium and other chemical elements can be extracted from them.
Large aluminum particles are separated from aluminum hydroxide by filtration. The resulting substance is washed, dried and heated to the boiling point of water. As a result, alumina is formed. It does not have an expiration date. Alumina must be stored in dry places. The substance is transported in railway cars.
Production of aluminum from alumina
Manufacturers are actively improving the technology for producing aluminum from alumina, trying to produce the metal with minimal energy consumption and the least impact on the environment. Modern electrolytic shops use inert anodes, which eliminates the use of coal. They can be used for several decades.
As a result of the use of innovative technologies during the electrolysis of alumina, no carbon dioxide is released into the atmosphere. Electrolysis baths produce pure oxygen. This allows you to reduce costs on ventilation mechanisms designed to timely remove carbon dioxide from the room. Electrolysis uses at least 2 T of alumina, 0.1 T of cryolite and a small amount of fluorides.
Aluminum refining
The metal formed as a result of electrolysis contains a small amount of metal and gaseous substances:
- silicon;
- iron;
- zinc;
- carbon;
- hydrogen;
- nitrogen;
- ozone;
- carbon dioxide.
Impurities worsen the properties of the metal. Therefore, during production they are removed by refining. This procedure is carried out using 2 methods:
- Chlorination: carried out at a temperature of 750°C. Aluminum is blown with a chloride solution. Chlorination is carried out in special ladles for 12 minutes.
- Electrolytic method: carried out using fluoride and chloride salts. The metal is subjected to heat treatment and anodic dissolution. As a result, excess impurities are removed from the molten substance.
After the refining procedure, the purity of the metal is 99.5 - 99.9%. This procedure also removes 1% aluminum from the substance being refined.
Raw materials
In the natural environment, aluminum is found only in the form of ores - bauxite. These substances are presented in the form of hydroxides, corundum and kaolinite. They contain over 40 chemical elements. Alumina in bauxite is 45%.
One of the most important parameters of aluminum ores is the silicon module, which characterizes the ratio of the contents of aluminum and silicon oxides. It must be at least 2.6. There are over 18 billion tons of bauxite in the bowels of the Earth.
At current production rates, aluminum can be produced from this raw material until 2122.
Necessary equipment
The following equipment is required to mine bauxite, convert the ores into alumina, and extract the pure metal:
- Alumina distribution mechanisms: designed for transporting powdered aluminum oxide inside the workshop and dosed supply of alumina to electrolysis machines.
- Cathode bus bars: These are flexible strips of cathode runs attached to cathode bus bars made of steel materials.
- Gas cleaning plants: used to clean the room from gases generated during the production of aluminum fluoride by the dry method.
- Installation equipment: cranes for linear and technical purposes.
- Electrolyser: A device for separating the major components of alumina using electric current during electrolysis.
Depending on the technological features of production, a large number of drum rotary kilns are required. They are used in dry production methods. When organizing an enterprise, it is important to provide equipment for alumina electrolysis with electricity.
Source: https://stankiexpert.ru/tehnologii/proizvodstvo-alyuminiya.html
Primary aluminum
Almost all modern aluminum is produced using the Hall-Héroult process, independently developed by two different people - Charles Hall and Paul Héroux in 1886. Aluminum oxide is dissolved in pre-molten sodium hexafluoroaluminate and, by electrolysis, pure aluminum is accumulated on an anode mass made of graphite or consumable coke electrodes.
The electrolysis of primary aluminum requires a huge amount of electricity, so all aluminum production is concentrated near sources of inexpensive energy - hydroelectric power plants. For example, in Russia, the Irkutsk Aluminum Plant (IrkAZ) is located in close proximity to the Irkutsk Hydroelectric Power Station. The Krasnoyarsk Aluminum Plant consumes energy from the Krasnoyarsk Hydroelectric Power Station, the largest Bratsk Hydroelectric Power Station operates at BrAZ.
You can view the full list of aluminum smelters in Russia by following the link.
To produce one ton of technical purity aluminum requires two tons of alumina (aluminum ore), about 70 kg of cryolite (sodium hexafluoroaluminate), 39 kg of aluminum fluoride and 580 kg of electrodes (anodes). Electricity costs to produce 1000 kg of primary aluminum are approximately 16,000 kW/h.
In nature, aluminum is found in the following geological forms:
- Alexandrite
- Emerald
- Aquamarine
- Feldspar
- Ruby (sapphire, corundum)
- Alunites
- Nephelines
- Bauxite
- Alumina (a mixture of magnesite, limestone, kaolin with silica sand)
- Native aluminum is found in extremely rare anomalous zones on Earth, in the craters of volcanoes.
Also, a small amount of aluminum in the form of dissolved compounds is found in fresh (from 0.001 to 12 mg/l) and sea water (~0.01 mg/l).
History of aluminum production
The first officially confirmed information about the production of pure aluminum dates back to 1825, when the Danish alchemist Hans Oersted was able to isolate several milligrams of pure aluminum. Two years later, in 1827, he obtained several small grains of primary aluminum by heating aluminum chloride with potassium. These were insignificant volumes of metal and the cost exceeded the cost of gold at that time.
The first industrial method of technical purity aluminum was developed by the Frenchman Sainte-Clair Deville, financed by Napoleon himself. The industrial production of aluminum consisted of replacing aluminum with sodium from sodium chloride and aluminum. Over half a century of using this method, about 200 tons of pure metal were obtained. And he also produced the first aluminum by slow electrolysis of molten sodium aluminum chloride.
The first pure aluminum production plant was built in 1885 in Germany. The plant operated using a simplified Deville technology; aluminum was separated by the interaction of magnesium and cryolite. Over five years of operation, the aluminum smelter produced 60 tons of primary aluminum.
In 1886, simultaneously in two different parts of the world - in France and the USA, a method for producing primary aluminum by electrolysis was developed. At that time, much depended on the shortage of electricity and insufficiently developed technologies in the field of electrical engineering. With the advent of this method, market prices for aluminum fell tens of times, which made it possible to use aluminum much more widely.
The Volkhov Aluminum Plant was the first to be built in Russia. Now this enterprise produces aluminum of high purity 99.999. The start of production took place in 1932. And by 1939, the USSR aluminum industry produced 50 thousand tons of aluminum, moving to fully satisfy the internal needs of the industry at that time.
The Second World War actively stimulated the growth of the aluminum industry. In pre-war times, 620 tons per year were produced worldwide, and already during the war, in 1943, it reached 2 million tons. This was due to the large consumption of metal in aviation and other military equipment. Aluminum gunpowder was also actively used during the Second World War.
You can read in more detail about the history of industrial production on the website.
Aluminum industry
The aluminum industry consists of various stages and directions:
1. Search, development and extraction of aluminum ore, usually bauxite;
2. Enrichment of aluminum oxide. Alumina production;
3. Production of anode mass;
4. Production of the necessary chemical components for electrolysis;
5. Directly the process of aluminum electrolysis;
6. Smelting of aluminum metal into ingots, repeated electrolysis to obtain high and special purity aluminum;
7. Production of aluminum semi-finished products.
Aluminum is a light, silvery-white metal, the most abundant in the earth's crust and the third most abundant element in the periodic table after oxygen and silicon. In nature, this metal is almost always found in the form of a strong compound with oxygen: aluminum oxide.
Primary aluminum production
Obtaining primary aluminum (pure metal) is more labor-intensive and complex than with other metals, since its ores have a very high melting point (nifeline, corundum, bauxite and others).
Substitution in combination with carbon is also not used, since the reduction coefficient of aluminum is higher than that of carbon.
Currently, a method of intermediate replacement with decomposition at a temperature of 2000 degrees is being actively developed, but this is still a future technology that is not used in the actual production of primary aluminum.
Source: http://a1um.ru/aluminium-pervichnuy.html
What is made from aluminum
Aluminum is a chemical element of the third group of the periodic table.
we are elements of D.I. Mendeleev. Its serial number is 13, atomic mass
26.98. Aluminum has no stable isotopes.
Chemical properties
Interaction with non-metals
It interacts with oxygen only in a finely divided state at high temperatures:
the reaction is accompanied by a large release of heat.
Above 200°C it reacts with sulfur to form aluminum sulfide:
At 500°C – with phosphorus, forming aluminum phosphide:
At 800°C it reacts with nitrogen, and at 2000°C – with carbon, forming nitride and carbide:
It reacts with chlorine and bromine under normal conditions, and with iodine when heated, in the presence of water as a catalyst:
Does not interact directly with hydrogen.
With metals it forms alloys that contain intermetallic compounds - aluminides, for example, CuAl2, CrAl7, FeAl3, etc.
Interaction with water
Aluminum purified from the oxide film vigorously interacts with water:
As a result of the reaction, slightly soluble aluminum hydroxide is formed and hydrogen is released.
Interaction with acids
Easily reacts with dilute acids, forming salts:
8Al + 30HNO3 = 8Al(NO3)3 + 3N2O + 15H2O (nitrogen and ammonium nitrate can also be the product of nitric acid reduction).
It does not react with concentrated nitric and sulfuric acids at room temperature; when heated, it reacts to form a salt and the acid reduction product:
Interaction with alkalis
Aluminum is an amphoteric metal; it reacts easily with alkalis:
in solution to form sodium tetrahydroxodiaquaaluminate:
when fused to form aluminates:
Recovery of metals from oxides and salts
Aluminum is an active metal, capable of displacing metals from their oxides. This property of aluminum has found practical application in metallurgy:
Areas of use
Aluminum has a number of properties that distinguish it from other metals. This is a low density of aluminum, good ductility and sufficient mechanical strength, high thermal and electrical conductivity.
Aluminum is non-toxic, non-magnetic and corrosion resistant to a number of chemicals.
Thanks to all these properties, as well as its relatively low cost compared to other non-ferrous metals, it has found extremely wide application in a wide variety of branches of modern technology.
A significant part of aluminum is used in the form of alloys with silicon, copper, magnesium, zinc, manganese and other metals. Industrial aluminum alloys usually contain at least two or three alloying elements, which are introduced into aluminum mainly to increase mechanical strength.
The most valuable properties of all aluminum alloys are low density
(2.65÷2.8), high specific strength (tensile strength to density ratio) and satisfactory resistance to atmospheric corrosion.
Aluminum alloys are divided into wrought and cast alloys. Wrought alloys are subjected to hot and cold working, so they must have high ductility. Of the wrought alloys, duralumins, alloys of aluminum with copper, magnesium and manganese, are widely used. Having a low density, duralumin has mechanical properties close to soft steel grades. From deformable
aluminum alloys, as well as from pure aluminum as a result of pressure treatment (rolling, stamping) sheets, strips, foil, wire, rods of various profiles, and pipes are obtained. Aluminum consumption for the manufacture of these semi-finished products is about 70% of its global production.
The rest of the aluminum is used for the manufacture of foundry alloys, powders, deoxidizers, and for other purposes.
Shaped castings of various configurations are produced from foundry alloys. Widely known casting alloys based on aluminum are silumins, in which the main alloying additive is silicon (up to 13%).
Currently, aluminum and its alloys are used in almost all areas of modern technology. The most important consumers of aluminum and its alloys are the aviation and automotive industries, railway and water transport, mechanical engineering, electrical engineering and instrument making, industrial and civil construction, the chemical industry, and the production of consumer goods.
The use of aluminum and its alloys in all types of transport, and primarily air transport, has made it possible to solve the problem of reducing the dead weight of vehicles and dramatically increasing their efficiency
applications. Aircraft structures, engines, blocks, cylinder heads, crankcases, gearboxes, pumps and other parts are made from aluminum and its alloys.
Aluminum and its alloys are used to trim railway cars, to make the hulls and chimneys of ships, rescue boats, radar masts, and gangways.
Aluminum and its alloys are widely used in the electrical industry for the manufacture of cables, busbars, capacitors, and AC rectifiers. In instrument making, aluminum and its alloys are used in the production of film and photographic equipment, radiotelephone equipment, and various control and measuring instruments.
Due to its high corrosion resistance and non-toxicity, aluminum is widely used in the manufacture of equipment for the production and storage of strong nitric acid, hydrogen peroxide, organic substances and food products. Aluminum foil, being stronger and cheaper than tin, has completely replaced it as a packaging material for food products.
Aluminum is increasingly used in the manufacture of containers for canning and storing agricultural products, for the construction of granaries and other prefabricated structures.
Being one of the most important strategic metals, aluminum, like its alloys, is widely used in the construction of aircraft, tanks, artillery, missiles, incendiaries, as well as for other purposes in military equipment.
Source: https://MyTooling.ru/instrumenty/chto-proizvodjat-iz-aljuminija
How aluminum is mined and produced in industrial conditions
Aluminum is one of the most common metals in the earth's crust. This metal is the lightest and also has good thermal conductivity. It lends itself well to machining by casting, bends well, and is recyclable. Its main physical properties:
- It has a silvery color (with a hint of white);
- Easy;
- Density is about 2713 kg per square meter;
- Boiling point from 2518.9 degrees Celsius;
- High ductility up to 50%.
Aluminum production
Alumina deposits are present in almost all countries of the world. The initial stage of mining is Bauxite ore. This name is derived from the locality of Baux, located in the south of France. The top five countries in the sale and production of bauxite rock are the following countries:
- Russia up to 4.5 million tons per year;
- China up to 13.50 million tons per year;
- USA up to 2.5 million tons per year;
- Canada up to 3.5 million tons per year;
- Australia up to 2.0 million tons per year.
In addition, this included:
- Iceland up to 0.50 million tons per year;
- Tajikistan up to 0.43 million tons per year;
- UAE up to 0.90 million tons per year;
- Germany up to 0.56 million tons per year;
- Brazil up to 1.70 million tons per year;
- India up to 1.30 million tons per year.
Metal ore is divided according to quality, and the content of foreign impurities affects the criteria for demand in the sales market:
- An increased amount of sulfur complicates the process of processing the substance into a pure alloy;
- High silicon module content improves product quality;
- The presence of carbonates in the ore complicates the process of processing the rock;
- The lowest iron content makes it easier to extract metal from underground.
Raw materials for production
The following categories of chemical elements are included in the production of aluminum:
Nephelines . They consist of nepheline syenites and urtites. The main components of the latter are apatite and nepheline. The components are processed and an apatite nepheline concentrate is obtained.
Alunite . It is a basic aluminum and sodium sulfate. It is a complex raw material consisting of sulfuric anhydride and alkali.
Cryolite . The connection is created artificially. Fluorspar is diluted with sulfuric acid in special self-stirring furnaces. The resulting volatile fluorosilicic acid is filtered using water towers installed above the baths. Afterwards, the industrial solution is cleaned with soda.
https://www.youtube.com/watch?v=VVAAIF-hbLo
The next stage is aimed at obtaining cryolite. Hydrofluoric acid is diluted with aluminum hydroxide and soda, immersed in large boilers, where metal ore is smelted. The cryolite settles, then it is filtered and dried at a temperature of 150 degrees Celsius.
Bauxite alloy consists of oxides of iron, silicon and aluminum hydroxides. This raw material is used as a flux in smelting metallurgy.
The mined soil looks like clay. Has a homogeneous structure. A pisiform striped pattern is often encountered. The tropical climate contributes to the formation of high-quality ore composition. Under high temperatures, minerals in the earth's crust decompose, forming the final product Bauxite. Next, the resulting composition is purified from gas impurities.
Aluminum alloy has a strong bond with oxygen, so the process of extracting it from the soil is more difficult than other metals. To obtain the desired compound, alumina is processed in stages:
- Metal ore deposits are mined;
- Alumina or aluminum oxide is obtained from the deposits;
- Next, the chemical element is split in a molten electrolyte.
The final point of the recycling process was named Hall-Heroult in 1886. The main developers of the modern melting method were Charles Hall and Paul Heroux.
To produce one ton of silver compound, 2000 kg are required. alumina, 40 kg. fluoride, 70 kg. cryolite and about 600 kg. graphite electrodes.
Aluminum production technologies
The metal is obtained by extracting alumina from bauxite ores. It is produced by three methods:
- Acidic dissolution of aluminum;
- Alkaline dissolution of aluminum;
- Electrolytic method.
Frequently used methods for obtaining metal are alkaline dissolution of aluminum ore and electrolytic production of aluminum. The alkali quickly dissolves the aluminum chemical solution. The mixture is diluted with aluminum hydroxypod. Manufacturing occurs in stages:
- The alumina composition is crushed with the addition of alkali or lime to a homogeneous consistency;
- The crushed pulp is placed in an autoclave at a temperature of +240 degrees Celsius and leached at high temperatures;
- In a solution of sodium aluminate and sodium silicate, the insoluble element sodium aluminosilicate is formed. The waste solution is filtered by adding a dilute alkali mixture at a temperature of +140 degrees Celsius;
- The metal solution is pumped into decomposers (baths with a stirring device) with the addition of hydroxide. There, aluminum hydroxide is extracted at a low temperature (+80 degrees Celsius);
- The resulting mixture is sent for calcination. The oven temperature reaches +1300 degrees Celsius; when the oven rotates, the consistency completely evaporates the moisture.
Electrolysis process
Electrolytic reduction occurs by placing alumina metal rock into electrolysis every half hour. There, raw materials are fired at a temperature of about 1000 degrees Celsius. Industrial scale allows the use of baths with baked anodes for metal ore:
- The raw material is immersed in a vessel where the reaction of alumel ore occurs;
- Aluminum oxide produces aluminum chloride;
- The chlorine compound is filtered;
- The metal settles on the cathode.
Baths without the use of liquid cryolite save up to 35% energy, and also reduce the cost of expensive electrochemical cryolite.
Metal refining
Aluminum rock is immersed in a refining bath, after which it is divided into three components:
- Molten alumina (bottom layer);
- An electrolyte consisting of a mixture of barium chloride, fluorides or sodium;
- Metal film (top layer).
The composition of the anode is: nickel, manganese, lead or tin. A slight presence of magnesium is allowed, which is eliminated by chlorine flux. The end result is 99.9% aluminum.
The metal element is used to create vehicles, construct buildings or structures, as well as construct electronic devices or electrical wiring. The metal retains its original qualities, which allows the composition to be reused in production.
New technologies for smelting metal alloys are being developed that make it possible to economically consume electricity, as well as the world's ore reserves.
Source: https://oxmetall.ru/metalli/alyuminij/kak-proizvoditsya-alyuminij
What was the first product made from aluminum?
April 25, 2017 at 4:01 pm
Life.ru talks about where else aluminum can be used.
In the sky and in space
Aluminum first “flyed” in 1900 - in the form of the frame and propellers of Ferdinand Zeppelin’s huge LZ-1 airship. But the soft, pure metal was only suitable for slow lighter-than-air aircraft.
Truly “winged” aluminum was already five times stronger, since it contained manganese, copper, magnesium, zinc in different percentages - the sky and space were conquered by varieties of duralumin, an alloy invented at the beginning of the twentieth century by the German engineer Alfred Wilm .
The material was promising, but it also had many limitations - it required so-called aging, that is, it did not gain the strength inherent in it immediately, but only over time. Yes, and it could not be welded. And yet, the conquest of space began precisely with duralumin, from which the ball of the famous first artificial Earth satellite was also made.
Much later, at the height of the space age, aluminum-based alloys and materials with much more remarkable properties began to appear.
For example, the friendship between aluminum and lithium has made it possible to make aircraft and rocket parts much lighter without reducing strength, and alloys with titanium and nickel have the property of “cryogenic hardening”: in the cold of space, their ductility and strength only increase.
The skin of the Buran space shuttle was made from a tandem of aluminum and scandium: aluminum-magnesium plates became much more tensile strength, while maintaining flexibility and doubling the melting point.
More modern materials are not alloys, but composites. But even in them the base is most often aluminum.
One of the modern and promising aerospace materials is called “boron-aluminum composite,” where boron fibers are sandwiched with layers of aluminum foil, forming an extremely strong and lightweight material under high pressures and temperatures. For example, the turbine blades of advanced aircraft engines are boron-aluminum load-bearing rods covered in a titanium “jacket.”
In the automotive industry and transport
Today, new Range Rover and Jaguar models feature 81% aluminum in their body structure. The first experiments with aluminum bodies are usually attributed to Audi, which presented the A8 made of light alloys in 1994.
However, back in the early twentieth century, this light metal on a wooden frame was the signature body style of the famous British sports cars Morgan.
The real “aluminum invasion” into the auto industry began in the 1970s, when factories began to massively use this metal for engine cylinder blocks and gearbox housings instead of the usual cast iron; a little later, light alloy wheels became widespread instead of stamped steel ones.
These days, the key trend in the auto industry is electricity. And light alloys based on aluminum are becoming particularly relevant in bodybuilding: the “energy-saving” metal makes the electric vehicle lighter, which means it increases the mileage on a single battery charge. Aluminum bodies are used by the Tesla brand, a trendsetter in the car market of the future, and that, in fact, says it all!
There are no domestic cars with aluminum bodies yet. But stainless and lightweight material is already beginning to penetrate the Russian transport sector. A typical example is the ultra-modern Vityaz-M high-speed trams, whose interiors are entirely made of aluminum alloys, which are practically eternal and do not require constant touch-up. It is worth noting that the creation of one tram interior requires up to 1.7 tons of aluminum, which is supplied by the Krasnoyarsk aluminum smelter Rusala.
“The ceiling, walls, racks are all aluminum.
And this is not just sheathing with sheets, the details are complex, combining finishing and load-bearing elements, and tunnels for ventilation and wiring,” says Vitaly Dengaev, general director of the Krasnoyarsk Machine-Building Components company, where the aluminum interiors of the Vityaz were created. “Plus, in addition to aesthetics, we also get the highest safety: unlike plastics and synthetics, the aluminum interior does not emit harmful substances if a fire occurs!”
On March 17 of this year, 13 Vityaz-M trams began running around Moscow and by April 5 they had already transported the first hundred thousand passengers! This fast and silent city transport with cabins for 260 people, with Wi-Fi, climate control, places for disabled people and strollers and other comfort elements, is designed for a service life of 30 years, which is twice as long as previous models. In the next three years, the capital will receive 300 Vityaz, 100 of which will be on the rails this season.
In the printers of the future
Elementary amateur 3D printers printing from plastic filament will no longer surprise anyone. Today begins the era of full-fledged serial 3D printing of metal parts.
Aluminum powder is perhaps the most common material for a technology called AF (from Additive Fabrication).
Additive in English is “additive”, and this is the deep meaning of the name of the technology: the part is not produced from a blank, from which excess material is cut off during processing, but, on the contrary, by adding material to the working area of the tool.
The metal powder comes out of the AF machine's dispenser and is laser sintered layer by layer into a single, strong mass of monolithic aluminum.
Parts that are made integral using the AF method amaze the imagination with their spatial complexity; It is impossible to perform them using classical methods even on the most modern metalworking machines! Due to the openwork design, parts created on additive printing machines from aluminum alloy powders have the strength of a monolith, while being several times lighter. They are produced without waste and quickly - such metal “laces” are indispensable in biomedicine, aviation and astronautics, precision mechanics, in the manufacture of molds, and so on.
Until recently, all technologies related to Additive Fabrication were foreign. But now domestic analogues are actively developing. For example, at the Ural Federal University (Ural Federal University) an experimental installation for the production of metal powders for AF-3D printing is being prepared. The installation operates on the principle of spraying molten aluminum with a jet of inert gas; this method will make it possible to obtain metal powders with any specified grain size parameters.
In construction and lighting
Aluminum can also be a facade and roofing material, the service life of which is not limited to a couple of years and which is extremely convenient for designers and installers! Special patented alloys and composites with a variety of properties have been developed for construction - Alclad, Kal-Alloy, Kalzip, Dwall Iridium. Aluminum can be used to stamp parts in which the roof plane is integral with the load-bearing elements. This is necessary, for example, to create retractable stadium roofs.
Which spacers are better: polyurethane or aluminum?
Coated with a special type of fluoropolymer, related to Teflon, aluminum roof parts can withstand enormous loads from wind and precipitation. And when constructing roofs of enormous size, where the total length of the sheet from edge to edge can reach several tens of meters, a special technology is used, the development of which was also made possible by the plasticity of aluminum.
To avoid the unreliable connection of many small sheets, aluminum tape several meters wide, rolled into a huge roll, is brought to the construction site, and right on the construction site it is passed through a special machine, which makes the even tape profiled, and therefore rigid. The aluminum profile is fed onto the roof of the building along special guides with rollers.
This technology was developed by the British Corus Group, one of the world leaders in the production of aluminum roofing sheets (now part of Tata Steel).
In our country, aluminum architecture is truly unfolding only now, lagging behind world rates, but vigorously catching up with them - recent examples of implementation include the roof of the Zenit Arena stadium in St. Petersburg, the facilities of the Kazan Universiade, the Sochi airport, a unique light-alloy bridge currently under construction in Nizhny Novgorod and other objects.
The building has been built, the roof has been erected, now we need light! And here aluminum is back in trend. It is not only a “winged” metal, but also a “metal of light”. There are now billions of LED lamps burning in the world and their number is growing every second. Each lamp has an aluminum heatsink that removes excess heat from the LED crystals, preventing them from overheating. But aluminum plays a much more important role in the manufacture of the base of the LEDs themselves - leucosapphire.
The Aluminum Association is convinced that within 2-3 years our enterprises will be able to completely replace imports of highly pure aluminum oxide into Russia, which will sharply stimulate domestic LED production.
Everywhere in our lives
We just don't always know about it! Almost all high-quality gadgets are made on the basis of aluminum alloys: frames and covers of smartphones, tablets, laptops, power bank cases and much more. Sports equipment, baby strollers, cooking utensils, radiators, furniture fittings - the list of areas where light metal is used is endless.
But why don't we always know about this? The fact is that aluminum and its alloys in “naked form”, like that well-known but hopelessly outdated aluminum spoon, are almost never found these days. Today the ball is ruled by anodizing technology, which allows parts made of aluminum and its alloys to be coated with a durable, wear-resistant oxide film.
Anodizing does not stain your hands and can achieve almost any color and texture.
One of the most promising household aluminum areas is bicycle frames. The aluminum frame is very light, making it very comfortable to lift the bike and ride it. The frame does not rust if the paint is damaged, alloying additives make the metal very strong, and technologies called “butting” and “hydroforming” make it possible to produce pipes of variable thickness and with any bends, lightening and strengthening the frame exactly where it is needed.
Millions of bikes - a huge market! However, for now, the frames of all two-wheelers sold and assembled in our country are imported. “However, a small revolution has emerged in this area: Rusal engineers have developed a special new alloy, ideal for bicycle frames, and are working to develop the production of frames in our country,” says Deputy editor of the Metal Supply and Sales magazine Leonid Khazanov. — The project is supported by Rusal, as the only Russian aluminum producer, the Tatprof aluminum profile plant located in Naberezhnye Chelny, which is ready to make pipes for frames, and the domestic company, the bicycle assembler Velomotors. If the planned scale of production is realized, our frames should become cheaper than Chinese ones and at the same time much higher in quality.”
Russia is the world leader in aluminum, one of the top three producers of this metal. The USSR began building aluminum smelters in the early thirties of the 20th century, completely getting rid of imports by the middle of the decade. However, strangely enough, we are truly entering the “aluminum era” only now.
The main owner of Rusal, Oleg Deripaska, has repeatedly stated that the level of aluminum consumption in Russia is much lower than the global average, and today it is finally time to break this trend and make maximum efforts and resources to create processing capacities in the country and displace imported products, the quality of which is often compromised a lot of questions.
For many years, design engineers avoided the use of aluminum, since aluminum alloys and composites simply did not appear in outdated regulatory documents - today, standards, GOSTs and SNIPs are revised and updated in the spirit of the times. And almost all areas of industry are waiting to discover new areas of use of this metal.
Source: http://ooo-asteko.ru/chto-bylo-pervym-izdeliem-sdelannym-iz-alyuminiya/
What was the first product made of aluminum - Metalworker's Guide
April 25, 2017 at 4:01 pm
Life.ru talks about where else aluminum can be used.
What is cast aluminum?
Our article will help you in choosing a frying pan, and will also reveal some of the subtleties and secrets of their production.
The most important thing to start with is to understand what kind of stove you will use the frying pan on, this is especially important if you have an induction stove or are planning to buy one in the near future, not all frying pans are suitable for such stoves, so pay attention to the usage icons by type of slabs.
Owners of ceramic slabs also need to be careful. With other stoves everything is much simpler - usually all frying pans are suitable for them, but just in case it would be a good idea to check the icons or description on the frying pan.
According to the types of materials from which frying pans are made, they are divided into cast iron, stainless steel and aluminum
Cast iron frying pans , as you know, have a magical aura of love from our grandmothers. Let's take a closer look. Cast iron has low thermal conductivity, which means it heats up slowly and unevenly.
Its non-stick properties are very conditional, and they become better only with prolonged use - the frying pan is gradually saturated with oil due to the porous structure of cast iron.
Such frying pans are quite heavy and require careful care - only hand washing, obligatory wiping with a dry towel and lubricating with vegetable oil after each use, otherwise the frying pan will rust.
Our grandmothers had no choice, and they treated everything with care and love, but we suggest considering more modern and easy-to-care materials.
Stainless steel pans have low thermal conductivity - they heat up slowly and unevenly and lack non-stick properties; they can be used without a non-stick coating mainly by experienced housewives or lovers of stews.
It is not rational to buy stainless steel frying pans with a special aluminum insert and a non-stick coating, since such frying pans will cost at least 30% more than aluminum frying pans with the same coating.
Aluminum frying pans with a non-stick coating have good thermal conductivity 4-5 times higher than that of steel and cast iron, so they heat up quickly and evenly and contribute to uniform frying of food.
A good non-stick coating will prevent your food from burning and will even make it healthier by allowing you to use minimal frying oil.
The TalleR company uses non-stick coatings Xylan Plus and QuanTanium from Whitford; these are reliable coatings with 2- and 3-layer coating with a thickness of 30-45 microns.
These coatings do not contain harmful substances such as nickel, heavy metals and perfluorooctanoic acid (PFOA) and are approved for use by the US Food and Drug Administration (FDA).
Let's move on to consider the types of aluminum frying pans according to production technology: cast, forged, stamped
When stamping, ready-made aluminum sheets are used, from which blanks are stamped by mechanical processing. This technology is simple and cheap, which explains the relatively low cost of the dishes.
During the stamping process, the structure of the metal changes, which somewhat reduces its thermal conductivity properties and reduces its resistance to deformation when heated. Manufacturers compensate for these shortcomings by increasing the thickness of aluminum or inserting an anti-deformation disk into the bottom.
It is advisable to use thin-walled aluminum up to 2.5 mm thick only for gas stoves.
Forged frying pans are made by pressing under high pressure on special forging machines. First, aluminum is heated to a temperature of 480–400 °C, then pressed under a pressure of 5000 tons.
During this process, aluminum particles are crushed and pulled in the desired direction, which subsequently leads to a fibrous, dense structure of the metal. Thanks to forging, products become more durable in quality and are not subject to any deformation than with other production technologies.
Source: https://varimtutru.com/litoy-alyuminiy-chto-eto-takoe/
Aluminum production
Aluminum is a chemical element that occupies a leading place among the most common metals in the earth's crust, as well as among the most frequently used. The amount of aluminum in the earth's crust reaches 9%. It is found only in the form of compounds that are represented by aluminum oxide or alumina.
Clay contains approximately 30% of this oxide.
This metal occupies an advantageous position among other types due to its properties. These include excellent ductility, excellent thermal and electrical conductivity, and at the same time low density.
In this article we will talk about the features of aluminum production.
Aluminum production technology
Aluminum production includes the following technological processes:
- bauxite mining
- extraction of alumina (aluminum oxide) from aluminum ores (bauxite)
- release from aluminum oxide.
- final cleaning of aluminum.
From 4-5 tons of bauxite you can get about 2 tons of alumina, from which, as a result of further processing, you will get 1 ton of aluminum. Aluminum production begins with the extraction of aluminum ores, of which there are several types in nature. However, the main raw material for obtaining the metal is bauxite.
Bauxite is of high quality if it contains more than 50% aluminum oxide. Experts provide information on the amount of 18.6 billion tons of bauxite contained in the earth's crust. Today's production levels guarantee that there will be enough bauxite for another 100 years.
There are seven bauxite-bearing areas in the world:
- West and Central Africa (mostly in Guinea)
- South America: Brazil, Venezuela, Suriname, Guyana
- Caribbean: Jamaica
- Oceania and southern Asia: Australia, India
- China
- Mediterranean: Greece and Türkiye
- Ural (Russia).
Bauxites are:
- hard, high density
- loose, easy to crumble.
The color of bauxite is most often brick-red, but may be reddish or brown due to the admixture of iron oxide.
If there is little iron in the rock, bauxite will be white or gray in color. However, there are also ores that are yellow, dark green and even variegated - with blue, red-violet or black veins. Bauxite is mined using the open-pit method.
Special machines “cut” the ore layer by layer from the surface of the earth and transport it to a further processing point. But there are also areas on Earth in which aluminum ore lies at great depths. In this case, to extract ore, mines are built. The deepest mine “Cheremukhovskaya-Glubokaya” is located in Russia, in the Urals, its depth reaches 1550 meters.
Creation of alumina
The further process of aluminum production involves the production of alumina by acid, alkaline and electrolytic methods. The acid method is used when working with high grades of raw materials.
During the alkaline method, the aluminum solution decomposes under the influence of introduced aluminum hydroxide.
After this, the solution is evaporated. The most popular is the alkaline method.
It is known that an aluminum solution begins to decompose almost instantly if aluminum hydroxide is introduced into it. This method consists of two steps:
- bauxite preparation. The ore is crushed. It is ground in special mills. Caustic alkali, bauxite and a small amount of lime are added to the mills. The resulting pulp is sent for leaching
- Leaching of bauxite is actually its chemical decomposition upon contact with an aqueous solution of alkali. In this reaction, aluminum oxide hydrates, reacting with alkali, enter the solution in the form of sodium aluminate, and silica contained in bauxite, reacting with the alkali, enters the solution in the form of sodium silicate. These compounds react with each other to form insoluble sodium aluminosilicate. This residue contains oxides of iron and titanium, which give the residue a red color. This residue is called red mud. Red mud is separated from the aluminate solution by washing in thickeners. In this case, the red mud precipitates, and the remaining aluminate solution is filtered.
Filtration involves sending the solution into large containers with stirrers.
From this solution, cooled to 60°C, aluminum hydroxide is obtained with constant stirring. It is imperative to add a large amount of solid hydroxide to these containers with stirrers. The very last stage is the dehydration of aluminum hydroxide. It is carried out in tubular, constantly rotating kilns.
Electrolysis and refining
Metallurgical production of aluminum continues while loading anode mass, alumina, and fluorine salt into the electrolyzer. During the electrolysis process, carbon oxides are released from clay, as well as fluoride substances in a gaseous state. At the same time, a certain volume of the anode mass is consumed as foam, which is removed from the surface of the electrolyte itself. Theoretically, to obtain 1 kg of aluminum, 1.9 kg of alumina is needed.
The rest of it contains various impurities. However, practice shows that much more raw materials are spent. It all depends on the type of clay, the equipment used and a number of other factors. In the electrolysis process, the main apparatus is a special bath (electrolyzer) in which there are carbon blocks.
An electric current with a power of up to 150,000 A is supplied to the bath, and carbon anodes are placed in the tank itself, which burn at the end of the release of pure oxygen and form carbon monoxide.
Anodes come in two types:
- obtained by burning coal blocks whose weight exceeds 1 ton
- self-burning, which include coal briquettes that are subjected to baking during the electrolysis process.
Electrolysis of aluminum oxide is carried out at a temperature in the electrolyzer of about 970°C. Aluminum deposits on the cathode. At the end of this stage, aluminum acquires a marketable form, for example, ingots, pigs or wire. Aluminum production centers
The largest aluminum producer can be called the Rusal company, producing over 4 million tons of aluminum annually. In addition, the list of the largest aluminum manufacturers in Russia includes:
- The Bratsk aluminum plant, which produces 30% of Russian aluminum and 4% of the world's aluminum. The company uses 75% of the electricity generated at the Bratsk hydroelectric power station
- SUAL enterprise, which specializes in working with aluminum alloys
- JSC BAZ company operating in the production and extraction of alumina and aluminum hydroxide
- VgAZ is an enterprise for the production of primary aluminum.
According to the US Geological Survey, China ranked first in the world in aluminum production in 2016. Russia is in second place, Canada is in third.
List of aluminum industry enterprises of the Russian FederationFactory
Location
Year of commissioning
| KAZ | Murmansk region, Kandalaksha | 1951 |
| NkAZ | Kemerovo region, Novokuznetsk | 1943 |
| KrAZ | Krasnoyarsk region, Krasnoyarsk | 1964 |
| BrAZ | Irkutsk region, Bratsk | 1966 |
| SAZ | Republic of Khakassia, Sayanogorsk | 1985, 2006 |
| IrkAZ | Irkutsk region, Shelekhov | 1960 |
| NAZ | Republic of Karelia, Nadvoitsy village | 1954 |
| VgAZ | Volgograd | 1959 |
| BoAZ | Krasnoyarsk region, Boguchansky district | 2015 |
| AGK | Krasnoyarsk region, Achinsk | 1970 |
| Pikalevo Alumina Refinery | Leningrad region, Pikalevo | 1959 |
| BAZ | Sverdlovsk region, Krasnoturinsk | 1943 |
| UAZ | Sverdlovsk region, Kamensk-Uralsky | 1939 |
Source: http://mining-prom.ru/cvetmet/alyuminiy/proizvodstvo-alyuminiya/
