Aluminum ore reserves. Aluminum ore properties

Aluminum is a metal coated with a dull silver oxide film, the properties of which determine its popularity: softness, lightness, ductility, high strength, corrosion resistance, electrical conductivity and lack of toxicity. In modern high technologies, the use of aluminum is given a leading place as a structural, multifunctional material.

The greatest value for industry as a source of aluminum is natural raw materials - bauxite, a component of the rock in the form of bauxite, alunite and nepheline.

Varieties of alumina-containing ores

More than 200 minerals are known that contain aluminum.

Only such rock is considered as a raw material source, which can meet the following requirements:

Feature of bauxite natural rock

Natural deposits of bauxites, nephelines, alunites, clays, and kaolins can serve as a raw material source. Bauxites are the most saturated with aluminum compounds. Clays and kaolins are the most common rocks with a significant content of alumina. The deposits of these minerals are on the surface of the earth.

Bauxite in nature exists only in the form of a binary compound of a metal with oxygen. This compound is obtained from natural mountain ores in the form of bauxite, consisting of oxides of several chemical elements: aluminum, potassium, sodium, magnesium, iron, titanium, silicon, phosphorus.

Depending on the deposit, bauxites contain from 28 to 80% alumina in their composition. This is the main raw material for obtaining a unique metal. The quality of bauxite as a raw material for aluminum depends on the content of alumina in it. This defines the physical properties bauxite:

Bauxites, kaolins, clays contain impurities of other compounds in their composition, which, during the processing of raw materials, are released into separate industries.

Only in Russia are deposits with deposits of rocks, in which alumina is a lower concentration, used.

Recently, alumina began to be obtained from nephelines, which, in addition to alumina, contain oxides of such metals as potassium, sodium, silicon and, no less valuable, alum stone, alunite.

Methods for processing aluminum containing minerals

Technology for obtaining pure alumina from aluminum ore has not changed since the discovery of this metal. Its production equipment is being improved, which makes it possible to obtain pure aluminum. The main production stages for obtaining pure metal:

• Extraction of ore from developed deposits.
• Primary processing from waste rocks in order to increase the concentration of alumina is a beneficiation process.
• Obtaining pure alumina, electrolytic reduction of aluminum from its oxides.

The production process ends with a metal with a concentration of 99.99%.

Extraction and enrichment of alumina

Alumina or aluminum oxides, in pure form does not exist in nature. It is extracted from aluminum ores using hydrochemical methods.

Deposits of aluminum ore in deposits usually blow up, providing a site for its extraction at a depth of approximately 20 meters, from where it is selected and launched into the process of further processing;

• Using special equipment (screens, classifiers), the ore is crushed and sorted, discarding waste rock (tailings). At this stage of alumina enrichment, washing and screening methods are used, as the most economically beneficial.
• The purified ore settled at the bottom of the concentration plant is mixed with a heated mass of caustic soda in an autoclave.
• The mixture is passed through a system of high-strength steel vessels. Vessels are equipped with a steam jacket that maintains the required temperature. The steam pressure is maintained at the level of 1.5-3.5 MPa until the complete transition of aluminum compounds from the enriched rock to sodium aluminate in a superheated sodium hydroxide solution.
• After cooling, the liquid goes through a filtration stage, which results in separation solid sediment and obtaining a supersaturated pure aluminate solution. When aluminum hydroxide residues from the previous cycle are added to the resulting solution, decomposition is accelerated.
• For the final drying of the alumina hydrate, a calcination procedure is used.

Electrolytic production of pure aluminum

Pure aluminum is obtained using a continuous process whereby calcined aluminum enters the stage of electrolytic reduction.

Modern electrolyzers represent a device consisting of the following parts:

Additional purification of aluminum by refining

If the aluminum extracted from the electrolyzers does not meet the final requirements, it is subjected to additional purification by refining.

In industry, this process is carried out in a special electrolyser, which contains three liquid layers:

During electrolysis, impurities remain in the anode layer and electrolyte. The yield of pure aluminum is 95–98%. The development of aluminum-containing deposits is given a leading place in national economy, thanks to the properties of aluminum, which currently ranks second only to iron in modern industry.

In modern industry, aluminum ore has won the greatest popularity. Aluminum is the most common metal of all the metals that exist today on earth. In addition, he belongs to the third place in the ranking in terms of the number of deposits in the bowels of the Earth. Also, aluminum is the lightest metal. Aluminum ore is a rock that serves as the material from which the metal is obtained. Aluminum has certain chemical and physical properties, which allow adapting its application to completely different areas of human activity. Thus, aluminum has found its wide application in such industries as engineering, automotive, construction, in the production of various containers and packaging, electrical engineering, and other consumer goods. Almost every household appliance used daily by a person contains aluminum in one quantity or another.

There are a huge number of minerals, in the composition of which the presence of this metal was once discovered. Scientists have come to the conclusion that this metal can be mined from more than 250 minerals. However, it is not profitable to extract metal from absolutely all ores, therefore, among all the existing diversity, there are the most valuable aluminum ores, from which the metal is obtained. These are: bauxites, nephelines, and also alunites. Of all aluminum ores, the maximum content of aluminum is noted in bauxites. It is in them that about 50% of aluminum oxides are located. As a rule, bauxite deposits are located directly on earth's surface in sufficient quantities.

Bauxite is an opaque rock that is red or gray in color. The strongest bauxite samples on the mineralogical scale are estimated at 6 points. They come in different densities from 2900 to 3500 kg/m3, which directly depends on chemical composition.

Bauxite ores are distinguished by their complex chemical composition, which includes aluminum hydroxides, iron and silicon oxides, as well as from 40% to 60% alumina, which is the main raw material for aluminum production. It is worth saying that the equatorial and tropical terrestrial belts are the main area, which is famous for deposits of bauxite ore.

The formation of bauxite requires the participation of several components, including alumina monohydrate, boehmite, diaspore, and various iron hydroxide minerals along with iron oxide. The weathering of acidic, alkaline, and in some cases basic rocks, as well as the slow settling of alumina at the bottom of reservoirs, leads to the formation of bauxite ore.

From two tons of aluminum alumina, half as much is obtained - 1 ton. And for two tons of alumina, it is necessary to extract about 4.5 tons of bauxite. Aluminum can also be obtained from nephelines and alunites.

The former, depending on their grade, may contain from 22% to 25% alumina. While alunites are slightly inferior to bauxites, and 40% consist of aluminum oxide.

Aluminum ores of Russia

The Russian Federation is on the 7th line of the rating among all countries of the world in terms of the amount of aluminum ores mined. It should be noted that this raw material in the territory Russian state produced in huge quantities. However, the country is experiencing a significant shortage of this metal, and is not able to provide it in the amount necessary for the absolute supply of the industry. This is the primary reason why Russia has to purchase aluminum ores from other countries, as well as develop deposits with low quality mineral ores.

There are about 50 deposits in the state, the largest number of which is located in the European part of the state. However, Radynkskoye is the oldest aluminum ore deposit in Russia. Its location is the Leningrad region. It consists of bauxites, which since ancient times have been the main and indispensable material from which aluminum is subsequently produced.

Table 1. The largest bauxite deposits in Russia

Name	Content %		Percentage of total stocks	Degree of industrial development
	AL2O3	SiO2
"Little Red Riding Hood", Severouralsk	53.7	3.7	3.1	In developing
Kalinskoye, Severouralsk	56.0	2.6	3.6	In developing
Cheremuzovskoye, Sverdlo region	54.2	4.0	11.0	In developing
Novo - Kalinskoye, Severouralsk	55.0	3.1	7.0	In developing
Iksinskoe, st. Navolok	53.5	17.4	11.4	In developing
Vezhayu-Vorykvinskoye,. Komi Republic	49.2	0.1	11.3	In preparation
Vislovskoye, Belgorod	49.1	7.9	12.1	In reserve

Aluminum production in Russia

At the beginning of the 20th century, the aluminum industry was born in Russia. It was in 1932 that the first production plant for the production of aluminum appeared in Volkhov. And already on May 14 of the same year, the enterprise managed to get a batch of metal for the first time. Every year, new deposits of aluminum ores were developed on the territory of the state and new capacities were put into operation, which were significantly expanded during the Second World War. post-war period for the country was marked by the opening of new enterprises, the main activity of which was the production of fabricated products, the main material for which were aluminum alloys. At the same time, the Pikalevsky alumina enterprise was put into operation.

Russia is famous for its variety of factories, thanks to which the country produces aluminum. Of these, the most large-scale not only within the Russian state, but throughout the world, is UC Rusal. He managed to produce about 3.603 million tons of aluminum in 2015, and in 2012 the enterprise reached 4.173 million tons of metal.

Table of contents [-]

Aluminum is a metal coated with a dull silver oxide film, the properties of which determine its popularity: softness, lightness, ductility, high strength, corrosion resistance, electrical conductivity and lack of toxicity. In modern high technologies, the use of aluminum is given a leading place as a structural, multifunctional material. The greatest value for industry as a source of aluminum is natural raw materials - bauxite, a component of the rock in the form of bauxite, alunite and nepheline.

Varieties of alumina-containing ores

More than 200 minerals are known that contain aluminum. Only such rock is considered as a raw material source, which can meet the following requirements:

• Natural raw materials must have a high content of aluminum oxides;
• The deposit must comply with the economic feasibility of its industrial development.
• The rock must contain aluminum raw material in a form to be extracted in pure form by known methods.

Feature of bauxite natural rock

Natural deposits of bauxites, nephelines, alunites, clays, and kaolins can serve as a raw material source. Bauxites are the most saturated with aluminum compounds. Clays and kaolins are the most common rocks with a significant content of alumina. The deposits of these minerals are on the surface of the earth. Bauxite in nature exists only in the form of a binary compound of a metal with oxygen. This compound is obtained from natural mountain ores in the form of bauxite, consisting of oxides of several chemical elements: aluminum, potassium, sodium, magnesium, iron, titanium, silicon, phosphorus. Depending on the deposit, bauxites contain from 28 to 80% alumina in their composition. This is the main raw material for obtaining a unique metal. The quality of bauxite as a raw material for aluminum depends on the content of alumina in it. This defines the physical properties bauxite:

• The mineral is a latent crystalline structure or is in an amorphous state. Many minerals have solidified forms of hydrogels of simple or complex composition.
• The color of bauxites at various points of extraction ranges from almost white to red dark colors. There are deposits with a black color of the mineral.
• The density of aluminum-containing minerals depends on their chemical composition and is about 3,500 kg/m3.
• The chemical composition and structure of bauxite determines the solid properties mineral. The hardest minerals are distinguished by a hardness of 6 units on the scale adopted in mineralogy.
• As a natural mineral, bauxite has a number of impurities, most often these are oxides of iron, calcium, magnesium, manganese, impurities of titanium and phosphorus compounds.

Bauxites, kaolins, clays contain impurities of other compounds in their composition, which, during the processing of raw materials, are released into separate industries. Only in Russia are deposits with deposits of rocks, in which alumina is a lower concentration, used. Recently, alumina began to be obtained from nephelines, which, in addition to alumina, contain oxides of such metals as potassium, sodium, silicon and, no less valuable, alum stone, alunite.

Methods for processing aluminum containing minerals

The technology for obtaining pure alumina from aluminum ore has not changed since the discovery of this metal. Its production equipment is being improved, which makes it possible to obtain pure aluminum. The main production stages for obtaining pure metal:

• Extraction of ore from developed deposits.
• Primary processing from waste rocks in order to increase the concentration of alumina is a beneficiation process.
• Obtaining pure alumina, electrolytic reduction of aluminum from its oxides.

The production process ends with a metal with a concentration of 99.99%.

Extraction and enrichment of alumina

Alumina or aluminum oxides do not exist in nature in their pure form. It is extracted from aluminum ores using hydrochemical methods. Deposits of aluminum ore in deposits usually blow up, providing a site for its extraction at a depth of approximately 20 meters, from where it is selected and launched into the process of further processing;

• Using special equipment (screens, classifiers), the ore is crushed and sorted, discarding waste rock (tailings). At this stage of alumina enrichment, washing and screening methods are used, as the most economically beneficial.
• The purified ore settled at the bottom of the concentration plant is mixed with a heated mass of caustic soda in an autoclave.
• The mixture is passed through a system of high-strength steel vessels. Vessels are equipped with a steam jacket that maintains the required temperature. The steam pressure is maintained at the level of 1.5-3.5 MPa until the complete transition of aluminum compounds from the enriched rock to sodium aluminate in a superheated sodium hydroxide solution.
• After cooling, the liquid goes through a filtration stage, as a result of which a solid precipitate is separated and a supersaturated pure aluminate solution is obtained. When aluminum hydroxide residues from the previous cycle are added to the resulting solution, decomposition is accelerated.
• For the final drying of the alumina hydrate, a calcination procedure is used.

Electrolytic production of pure aluminum

Pure aluminum is obtained using a continuous process whereby calcined aluminum enters the stage of electrolytic reduction. Modern electrolyzers represent a device consisting of the following parts:

• Made of steel casing lined with coal blocks and plates. During operation, a dense film of solidified electrolyte is formed on the surface of the bath body, which protects the lining from destruction by the electrolyte melt.
• A layer of molten aluminum at the bottom of the bath, 10–20 cm thick, serves as the cathode in this setup.
• Current is supplied to the aluminum melt through carbon blocks and embedded steel rods.
• The anodes, suspended on an iron frame with steel pins, are provided with rods connected to a lifting mechanism. As it burns, the anode sinks down, and the rods are used as an element for supplying current.
• In the workshops, electrolyzers are installed sequentially in several rows (two or four rows).

Additional purification of aluminum by refining

If the aluminum extracted from the electrolyzers does not meet the final requirements, it is subjected to additional purification by refining. In industry, this process is carried out in a special electrolyser, which contains three liquid layers:

• Bottom - refinable aluminum with the addition of approximately 35% copper, serves as an anode. Copper is present to make the aluminum layer heavier, copper does not dissolve in the anode alloy, its density should exceed 3000 kg/m3.
• The middle layer is a mixture of fluorides and chlorides of barium, calcium, aluminum with a melting point of about 730°C.
• Upper layer - pure refined aluminum a melt that dissolves in the anode layer and rises. It serves as the cathode in this circuit. The current is supplied by a graphite electrode.

During electrolysis, impurities remain in the anode layer and electrolyte. The yield of pure aluminum is 95–98%. The development of aluminum-containing deposits is given a leading place in the national economy, due to the properties of aluminum, which currently occupies the second place after iron in modern industry.

In modern industry, aluminum ore is the most demanded raw material. The rapid development of science and technology has expanded the scope of its application. What is aluminum ore and where it is mined is described in this article.

Industrial value of aluminum

Aluminum is considered the most common metal. By the number of deposits in the earth's crust, it ranks third. Aluminum is also known to everyone as an element in the periodic table, which belongs to light metals.

Aluminum ore is a natural raw material from which this metal is obtained. It is mainly mined from bauxites, which contain aluminum oxides (alumina) in most– from 28 to 80%. Other rocks - alunite, nepheline and nepheline-apatite are also used as raw materials for aluminum production, but they are of poorer quality and contain much less alumina.

In non-ferrous metallurgy, aluminum occupies the first place. The fact is that due to its characteristics it is used in many industries. So, this metal is used in transport engineering, packaging production, construction, for the manufacture of various consumer goods. Aluminum is also widely used in electrical engineering.

To understand the importance of aluminum for humanity, it is enough to take a closer look at the household items that we use every day. A lot of household items are made of aluminum: these are parts for electrical appliances (refrigerator, washing machine, etc.), dishes, sports equipment, souvenirs, interior elements. Aluminum is often used to make different types containers and packaging. For example, cans or disposable foil containers.

Types of aluminum ores

Aluminum is found in more than 250 minerals. Of these, the most valuable for industry are bauxite, nepheline and alunite. Let's dwell on them in more detail.

bauxite ore

Aluminum is not found in nature in its pure form. It is mainly obtained from aluminum ore - bauxite. It is a mineral that mostly consists of aluminum hydroxides, as well as oxides of iron and silicon. Because of great content alumina (from 40 to 60%) bauxites are used as raw materials for the production of aluminum.

Physical properties of aluminum ore:

• opaque mineral of red and gray color of various shades;
• the hardness of the most durable samples is 6 on the mineralogical scale;
• the density of bauxites, depending on the chemical composition, ranges from 2900-3500 kg/m³.

Deposits of bauxite ore are concentrated in the equatorial and tropical zone earth. More ancient deposits are located on the territory of Russia.

How bauxite aluminum ore is formed

Bauxites are formed from monohydrate alumina hydrate, boehmite and diaspore, trihydrate hydrate - hydrargillite and accompanying minerals hydroxide and iron oxide.

Depending on the composition of nature-forming elements, there are three groups of bauxite ores:

1. Monohydrate bauxites - contain alumina in a one-water form.
2. Trihydrate - such minerals consist of alumina in a three-water form.
3. Mixed - this group includes the previous aluminum ores in combination.

Deposits of raw materials are formed as a result of the weathering of acidic, alkaline, and sometimes basic rocks, or as a result of the gradual deposition of a large amount of alumina on the sea and lake bottom.

Alunite ores

This type of deposits contains up to 40% aluminum oxide. Alunite ore is formed in the water basin and coastal zones under conditions of intense hydrothermal and volcanic activity. An example of such deposits is Lake Zaglinskoe in the Lesser Caucasus.

The breed is porous. It mainly consists of kaolinites and hydromicas. Of industrial interest are ore with an alunite content of more than 50%.

Nepheline

It is an aluminum ore of igneous origin. It is a full-crystalline alkaline rock. Depending on the composition and technological features of processing, several varieties of nepheline ore are distinguished:

• first grade - 60–90% nepheline; it contains more than 25% alumina; processing is carried out by sintering;
• the second grade - 40-60% nepheline, the amount of alumina is slightly lower - 22-25%; enrichment is required during processing;
• the third grade is nepheline minerals, which are of no industrial value.

World production of aluminum ores

For the first time, aluminum ore was mined in the first half of the 19th century in the south-east of France, near the town of Box. This is where the name bauxite comes from. At first, this branch of industry developed at a slow pace. But when humanity appreciated what kind of aluminum ore is useful for production, the scope of aluminum has expanded significantly. Many countries have begun searching for deposits in their territories. Thus, the world production of aluminum ores began to gradually increase. The figures confirm this fact. So, if in 1913 the global volume of ore mined was 540 thousand tons, then in 2014 it was more than 180 million tons.

The number of countries producing aluminum ore also gradually increased. Today there are about 30 of them. But over the past 100 years, the leading countries and regions have been constantly changing. So, at the beginning of the 20th century, the world leaders in the extraction of aluminum ore and its production were North America And Western Europe. These two regions accounted for about 98% of global production. A few decades later, countries became leaders in terms of quantitative indicators of the aluminum industry. of Eastern Europe, Latin America and Soviet Union. And already in the 1950s and 1960s, Latin America became the leader in terms of production. And in the 1980s-1990s. there was a rapid breakthrough in the aluminum industry in Australia and Africa. In the current global trend, the main aluminum mining countries are Australia, Brazil, China, Guinea, Jamaica, India, Russia, Suriname, Venezuela and Greece.

Ore deposits in Russia

In terms of production of aluminum ores, Russia ranks seventh in the world ranking. Although the deposits of aluminum ores in Russia provide the country with metal in in large numbers, it is not enough to fully provide the industry. Therefore, the state is forced to buy bauxite in other countries.

In total, 50 ore deposits are located on the territory of Russia. This number includes both places where the mineral is being mined, and deposits that have not yet been developed.

Most of the ore reserves are located in the European part of the country. Here they are located in the Sverdlovsk, Arkhangelsk, Belgorod regions, in the Komi Republic. All these regions contain 70% of all explored ore reserves of the country.

Aluminum ores in Russia are still mined in old bauxite deposits. These areas include the Radynskoye deposit in Leningrad region. Also, due to the shortage of raw materials, Russia uses other aluminum ores, the deposits of which are of the worst quality mineral deposits. But they are still suitable for industrial purposes. So, in Russia, nepheline ores are mined in large quantities, which also make it possible to obtain aluminum.

Bauxite is the main ore for aluminum production. The formation of deposits is associated with the process of weathering and transfer of material, in which, in addition to aluminum hydroxides, there are other chemical elements. Metal extraction technology provides an economically profitable industrial production process without the generation of waste.

Bauxite is the main ore for aluminum production

Characteristics of the ore mineral

The name of the mineral raw material for aluminum mining comes from the name of the area in France where the deposits were first discovered. Bauxite consists of aluminum hydroxides, as impurities it contains clay minerals, iron oxides and hydroxides.

By appearance bauxite is a stony, and more rarely clay-like, rock that is homogeneous or layered in texture. Depending on the form of occurrence in the earth's crust, they are dense or porous. Minerals are classified according to their structure:

• detrital - conglomerate, gravelstone, sandstone, pelitic;
• nodules - legumes, oolitic.

The groundmass of the rock in the form of inclusions contains oolitic formations of iron oxides or alumina. Bauxite ore is usually brown or brick in color, but there are deposits of white, red, gray, yellow shades.

The main minerals for the formation of ore are:

• diasporas;
• hydrogoethite;
• goethite;
• boehmite;
• gibbsite;
• kaolinite;
• ilmenite;
• alumina hematite;
• calcite;
• siderite;
• mica.

Distinguish bauxite platform, geosynclinal and oceanic islands. Deposits of aluminum ore were formed as a result of the transfer of weathering products of rocks with their subsequent deposition and sedimentation.

Industrial bauxites contain 28-60% alumina. When using ore, the ratio of the latter to silicon should not be lower than 2-2.5.

Gallery: bauxite stone (25 photos)

Bauxite (video)

Deposits and extraction of raw materials

The main raw materials for the industrial production of aluminum in the Russian Federation are bauxites, nepheline ores and their concentrates, concentrated on the Kola Peninsula.

Bauxite deposits in Russia are characterized by low quality of raw materials and difficult mining and geological conditions of extraction. There are 44 explored deposits within the state, of which only a quarter is exploited.

The main production of bauxite is carried out by JSC "Sevuralboksitruda". Despite the reserves of ore raw materials, the supply of processing enterprises is uneven. For 15 years, there has been a shortage of nephelines and bauxites, which leads to the import of alumina.

World reserves of bauxite are concentrated in 18 countries located in tropical and subtropical zones. The location of bauxite of the highest quality is confined to areas of weathering of aluminosilicate rocks in wet conditions. It is in these zones that the bulk of the global supply of raw materials is located.

The largest reserves are concentrated in Guinea. In terms of the extraction of ore raw materials in the world, the championship belongs to Australia. Brazil has 6 billion tons of reserves, Vietnam has 3 billion tons, India's bauxite reserves differ high quality, amount to 2.5 billion tons, Indonesia - 2 billion tons. The bulk of the ore is concentrated in the bowels of these countries.

Bauxites are mined by open pit and underground mining. Technological process processing of raw materials depends on its chemical composition and provides for the phased execution of work.

At the first stage, under the influence of chemical reagents, alumina is formed, and at the second stage, a metal component is extracted from it by electrolysis from a melt of fluoride salts.

Several methods are used to form alumina:

• sintering;
• hydrochemical;
• combined.

The application of techniques depends on the concentration of aluminum in the ore. Low quality bauxite is processed in a complex way. The charge obtained as a result of sintering from limestone soda and bauxite is leached with a solution. The metal hydroxide formed as a result of chemical treatment is separated and subjected to filtration.

Bauxite processing line (video)

Mineral resource application

The use of bauxite in various branches of industrial production is due to the versatility of the raw material in terms of its mineral composition and physical properties. Bauxite is an ore from which aluminum and alumina are extracted.

The use of bauxite in ferrous metallurgy as a flux in the smelting of open-hearth steel improves the technical characteristics of products.

In the manufacture of electrocorundum, the properties of bauxite are used to form an ultra-resistant, refractory material (synthetic corundum) as a result of melting in electric furnaces with the participation of anthracite as a reducing agent and iron filings.

The mineral bauxite with a low iron content is used in the manufacture of refractory, fast-hardening cements. In addition to aluminum, iron, titanium, gallium, zirconium, chromium, niobium and TR (rare earth elements) are extracted from ore raw materials.

Bauxites are used for the production of paints, abrasives, sorbents. Ore with a low iron content is used in the manufacture of refractory compositions.

In modern industry, aluminum ore has won the greatest popularity. Aluminum is the most common metal of all the metals that exist today on earth. In addition, he belongs to the third place in the ranking in terms of the number of deposits in the bowels of the Earth. Also, aluminum is the lightest metal. Aluminum ore is a rock that serves as the material from which the metal is obtained. Aluminum has certain chemical and physical properties that make it possible to adapt its application to completely different areas of human activity. Thus, aluminum has found its wide application in such industries as engineering, automotive, construction, in the production of various containers and packaging, electrical engineering, and other consumer goods. Almost every household appliance used daily by a person contains aluminum in one quantity or another.

Aluminum mining

There are a huge number of minerals, in the composition of which the presence of this metal was once discovered. Scientists have come to the conclusion that this metal can be mined from more than 250 minerals. However, it is not profitable to extract metal from absolutely all ores, therefore, among all the existing diversity, there are the most valuable aluminum ores, from which the metal is obtained. These are: bauxites, nephelines, and also alunites. Of all aluminum ores, the maximum content of aluminum is noted in bauxites. It is in them that about 50% of aluminum oxides are located. As a rule, bauxite deposits are located directly on the earth's surface in sufficient quantities. Bauxite is an opaque rock that is red or gray in color. The strongest bauxite samples on the mineralogical scale are estimated at 6 points. They come in different densities from 2900 to 3500 kg/m3, which directly depends on the chemical composition. Bauxite ores are distinguished by their complex chemical composition, which includes aluminum hydroxides, iron and silicon oxides, as well as from 40% to 60% alumina, which is the main raw material for aluminum production. It is worth saying that the equatorial and tropical terrestrial belts are the main area, which is famous for deposits of bauxite ore. The formation of bauxite requires the participation of several components, including alumina monohydrate, boehmite, diaspore, and various iron hydroxide minerals along with iron oxide. The weathering of acidic, alkaline, and in some cases basic rocks, as well as the slow settling of alumina at the bottom of reservoirs, leads to the formation of bauxite ore. From two tons of aluminum alumina, half as much is obtained - 1 ton. And for two tons of alumina, it is necessary to extract about 4.5 tons of bauxite. Aluminum can also be obtained from nephelines and alunites. The former, depending on their grade, may contain from 22% to 25% alumina. While alunites are slightly inferior to bauxites, and 40% consist of aluminum oxide.

Aluminum ores of Russia

The Russian Federation is on the 7th line of the rating among all countries of the world in terms of the amount of aluminum ores mined. It is worth noting that this raw material is mined in enormous quantities on the territory of the Russian state. However, the country is experiencing a significant shortage of this metal, and is not able to provide it in the amount necessary for the absolute supply of the industry. This is the primary reason why Russia has to purchase aluminum ores from other countries, as well as develop deposits with low quality mineral ores. There are about 50 deposits in the state, the largest number of which is located in the European part of the state. However, Radynkskoe is the oldest aluminum ore deposit in Russia. Its location is the Leningrad region. It consists of bauxites, which since ancient times have been the main and indispensable material from which aluminum is subsequently produced.

Aluminum production in Russia

At the beginning of the 20th century, the aluminum industry was born in Russia. It was in 1932 that the first production plant for the production of aluminum appeared in Volkhov. And already on May 14 of the same year, the enterprise managed to get a batch of metal for the first time. Every year, new deposits of aluminum ores were developed on the territory of the state and new capacities were put into operation, which were significantly expanded during the Second World War. The post-war period for the country was marked by the opening of new enterprises, the main activity of which was the production of fabricated products, the main material for which were aluminum alloys. At the same time, the Pikalevsky alumina enterprise was put into operation. Russia is famous for its variety of factories, thanks to which the country produces aluminum. Of these, the most large-scale not only within the Russian state, but throughout the world, is UC Rusal. He managed to produce about 3.603 million tons of aluminum in 2015, and in 2012 the enterprise reached 4.173 million tons of metal.

Aluminum / Aluminum (Al), 13

1.61 (Pauling scale)

1st: 577.5 (5.984) kJ/mol (eV) 2nd: 1816.7 (18.828) kJ/mol (eV)

Solid

2.6989 g/cm³

660°C, 933.5K

2518.82°C, 2792K

10.75 kJ/mol

284.1 kJ/mol

24.35 24.2 J/(K mol)

10.0 cm³/mol

cubic face-centered

(300 K) 237 W/(m K)

code symbol

Indicating that aluminum can be recycled Aluminum- an element of the 13th group of the periodic table of chemical elements (according to the outdated classification - an element of the main subgroup of group III), of the third period, with atomic number 13. It is designated by the symbol Al (lat. Aluminum). Belongs to the group of light metals. The most common metal and the third most common chemical element in the earth's crust (after oxygen and silicon). simple substance aluminum- light paramagnetic metal of silver-white color, easily molded, cast, machined. Aluminum has a high thermal and electrical conductivity, resistance to corrosion due to the rapid formation of strong oxide films that protect the surface from further interaction.

Story

Aluminum was first obtained by the Danish physicist Hans Oersted in 1825 by the action of potassium amalgam on aluminum chloride, followed by distillation of mercury. The name of the element is derived from lat. alumen- alum. Before the discovery of an industrial method for producing aluminum, this metal was more expensive than gold. In 1889, the British, wishing to honor the great Russian chemist D. I. Mendeleev with a rich gift, presented him with scales made of gold and aluminum.

Receipt

Aluminum forms a strong chemical bond with oxygen. Compared to other metals, the recovery of aluminum from ore is more difficult due to its high reactivity and the high melting point of most of its ores (such as bauxite). Direct reduction with carbon cannot be used because the reduction power of aluminum is higher than that of carbon. An indirect reduction is possible to obtain an intermediate product Al4C3, which decomposes at 1900-2000 ° C with the formation of aluminum. This method is under development but appears to be more advantageous than the Hall-Héroult process as it requires less energy and generates less CO2. The modern preparation method, the Hall-Héroult process, was developed independently by the American Charles Hall and the Frenchman Paul Héroux in 1886. It consists in the dissolution of aluminum oxide Al2O3 in a melt of Na3AlF6 cryolite, followed by electrolysis using consumable coke or graphite anode electrodes. This method of obtaining requires very large amounts of electricity, and therefore received industrial application only in the 20th century. The production of 1000 kg of crude aluminum requires 1920 kg of alumina, 65 kg of cryolite, 35 kg of aluminum fluoride, 600 kg of anodic graphite electrodes and about 17 MWh of electricity (~61 GJ). laboratory method The production of aluminum was proposed by Friedrich Wöhler in 1827 by the reduction of anhydrous aluminum chloride with potassium metal (the reaction proceeds when heated without air access):

AlCl3+3K→3KCl+Al(displaystyle (mathsf (AlCl_(3)+3Krightarrow 3KCl+Al)))

Physical properties

Aluminum microstructure on the etched surface of an ingot, 99.9998% pure, visible sector size about 55×37 mm

• Silver-white metal, light
• density - 2712 kg/m³
• melting point for technical aluminum - 658 °C, for high-purity aluminum - 660 °C
• specific heat of fusion - 390 kJ/kg
• boiling point - 2500 °C
• specific heat of evaporation - 10.53 MJ / kg
• specific heat capacity - 897 J/kg K
• tensile strength of cast aluminum - 10-12 kg/mm², deformable - 18-25 kg/mm², alloys - 38-42 kg/mm²
• Brinell hardness - 24…32 kgf/mm²
• high ductility: for technical - 35%, for clean - 50%, rolled in thin sheet and even foil
• Young's modulus - 70 GPa
• Aluminum has high electrical conductivity (37 106 S/m) and thermal conductivity (203.5 W/(m K)), 65% of the electrical conductivity of copper, has a high light reflectivity.
• Weak paramagnet.
• Temperature coefficient of linear expansion 24.58 10−6 K−1 (20…200 °C).
• Resistivity 0.0262..0.0295 Ohm mm²/m
• The temperature coefficient of electrical resistance is 4.3·10−3 K−1. Aluminum goes into a superconducting state at a temperature of 1.2 kelvin.

Aluminum forms alloys with almost all metals. The best known are alloys with copper and magnesium (duralumin) and silicon (silumin).

Being in nature

Prevalence

In terms of prevalence in the earth's crust, it occupies the 1st place among metals and the 3rd place among the elements, second only to oxygen and silicon. The mass concentration of aluminum in the earth's crust, according to various researchers, is estimated at 7.45 to 8.14%.

Natural aluminum compounds

In nature, aluminum, due to its high chemical activity, occurs almost exclusively in the form of compounds. Some of the naturally occurring aluminum minerals are:

• Bauxites - Al2O3 H2O (with admixtures of SiO2, Fe2O3, CaCO3)
• Nephelines - KNa34
• Alunites - (Na,K)2SO4 Al2(SO4)3 4Al(OH)3
• Alumina (mixtures of kaolins with sand SiO2, limestone CaCO3, magnesite MgCO3)
• Corundum (sapphire, ruby, emery) - Al2O3
• Feldspars - (K,Na)2O Al2O3 6SiO2, Ca
• Kaolinite - Al2O3 2SiO2 2H2O
• Beryl (emerald, aquamarine) - 3BeO Al2O3 6SiO2
• Chrysoberyl (alexandrite) - BeAl2O4.

However, in some specific reducing conditions(vents of volcanoes) trace amounts of native metallic aluminum were found. In natural waters, aluminum is found in the form of low-toxic chemical compounds, such as aluminum fluoride. The type of cation or anion depends primarily on the acidity aquatic environment. Aluminum concentrations in Russian water bodies range from 0.001 to 10 mg/l. IN sea ​​water its concentration is 0.01 mg/l.

Isotopes of aluminum

Natural aluminum consists almost entirely of the only stable isotope, 27Al, with negligible traces of 26Al, the longest-lived radioactive isotope with a half-life of 720 thousand years, formed in the atmosphere during the splitting of argon nuclei by 40Ar protons cosmic rays with high energies.

Chemical properties

Under normal conditions, aluminum is covered with a thin and strong oxide film and therefore does not react with classical oxidizing agents: with H2O, O2, HNO3 (without heating), H2SO4, but reacts with HCl. Due to this, aluminum is practically not subject to corrosion and therefore is widely demanded by modern industry. However, when the oxide film is destroyed (for example, upon contact with solutions of ammonium salts NH +, hot alkalis, or as a result of amalgamation), aluminum acts as an active reducing metal. It is possible to prevent the formation of an oxide film by adding metals such as gallium, indium or tin to aluminum. In this case, the surface of aluminum is wetted by low-melting eutectics based on these metals. Easily reacts with simple substances:

• with oxygen to form alumina:

4Al+3O2→2Al2O3(displaystyle (mathsf (4Al+3O_(2)rightarrow 2Al_(2)O_(3))))

• with halogens (except fluorine), forming chloride, bromide or aluminum iodide:

2Al+3Hal2→2AlHal3(Hal=Cl,Br,I)(displaystyle (mathsf (2Al+3Hal_(2)rightarrow 2AlHal_(3)(Hal=Cl,Br,I))))

• reacts with other non-metals when heated:

• with fluorine, forming aluminum fluoride:

2Al+3F2→2AlF3(displaystyle (mathsf (2Al+3F_(2)rightarrow 2AlF_(3))))

• with sulfur, forming aluminum sulfide:

2Al+3S→Al2S3(displaystyle (mathsf (2Al+3Srightarrow Al_(2)S_(3))))

• with nitrogen to form aluminum nitride:

2Al+N2→2AlN(displaystyle (mathsf (2Al+N_(2)rightarrow 2AlN)))

• with carbon, forming aluminum carbide:

4Al+3C→Al4C3(displaystyle (mathsf (4Al+3Crightarrow Al_(4)C_(3))))

Aluminum sulfide and aluminum carbide are completely hydrolyzed: Al2S3+6H2O→2Al(OH)3+3H2S(displaystyle (mathsf (Al_(2)S_(3)+6H_(2)Orightarrow 2Al(OH)_(3)+3H_(2) S))) Al4C3+12H2O→4Al(OH)3+3CH4(displaystyle (mathsf (Al_(4)C_(3)+12H_(2)Orightarrow 4Al(OH)_(3)+3CH_(4)))) With complex substances:

• with water (after removing the protective oxide film, for example, by amalgamation or hot alkali solutions):

2Al+6H2O→2Al(OH)3+3H2(displaystyle (mathsf (2Al+6H_(2)Orightarrow 2Al(OH)_(3)+3H_(2))))

• with alkalis (with the formation of tetrahydroxoaluminates and other aluminates):

2Al+2NaOH+6H2O→2Na+3H2(displaystyle (mathsf (2Al+2NaOH+6H_(2)Orightarrow 2Na+3H_(2)))) 2Al+6NaOH→2Na3AlO3+3H2(displaystyle (mathsf (2Al+6NaOHrightarrow 2Na_(3 )AlO_(3)+3H_(2))))

• Easily soluble in hydrochloric and dilute sulfuric acids:

2Al+6HCl→2AlCl3+3H2(displaystyle (mathsf (2Al+6HClrightarrow 2AlCl_(3)+3H_(2)))) 2Al+3H2SO4→Al2(SO4)3+3H2(displaystyle (mathsf (2Al+3H_(2)SO_ (4)rightarrow Al_(2)(SO_(4))_(3)+3H_(2))))

• When heated, it dissolves in acids - oxidizing agents that form soluble aluminum salts:

8Al+15H2SO4→4Al2(SO4)3+3H2S+12H2O(displaystyle (mathsf (8Al+15H_(2)SO_(4)rightarrow 4Al_(2)(SO_(4))_(3)+3H_(2)S+ 12H_(2)O))) Al+6HNO3→Al(NO3)3+3NO2+3H2O(displaystyle (mathsf (Al+6HNO_(3)rightarrow Al(NO_(3))_(3)+3NO_(2)+ 3H_(2)O)))

• restores metals from their oxides (aluminothermy):

8Al+3Fe3O4→4Al2O3+9Fe(displaystyle (mathsf (8Al+3Fe_(3)O_(4)rightarrow 4Al_(2)O_(3)+9Fe))) 2Al+Cr2O3→Al2O3+2Cr(displaystyle (mathsf (2Al+ Cr_(2)O_(3)rightarrow Al_(2)O_(3)+2Cr)))

Production and market

Aluminum production in millions of tons There is no reliable information about the production of aluminum before the 19th century. (Occurring sometimes with reference to Pliny's Natural History, the assertion that aluminum was known under the emperor Tiberius is based on a misinterpretation of the source). In 1825, the Danish physicist Hans Christian Oersted received several milligrams of metallic aluminum, and in 1827 Friedrich Wöhler was able to isolate aluminum grains, which, however, were immediately covered with a thin film of aluminum oxide in air. Until the end of the 19th century, aluminum was not produced on an industrial scale. Only in 1854, Henri Sainte-Clair Deville (his research was financed by Napoleon III, hoping that aluminum would be useful to his army) invented the first method for the industrial production of aluminum, based on the displacement of aluminum by sodium metal from double sodium chloride and aluminum NaCl AlCl3. In 1855, the first ingot of metal weighing 6-8 kg was obtained. For 36 years of application, from 1855 to 1890, 200 tons of aluminum metal were obtained by the Saint-Clair Deville method. In 1856, he also obtained aluminum by electrolysis of a sodium-aluminum chloride melt. In 1885, an aluminum production plant was built in the German city of Gmelingem, operating according to the technology proposed by Nikolai Beketov. Beketov's technology was not much different from the Deville method, but it was simpler and consisted in the interaction between cryolite (Na3AlF6) and magnesium. In five years, this plant produced about 58 tons of aluminum - more than a quarter of the world's production of metal by chemical means in the period from 1854 to 1890. The method, invented almost simultaneously by Charles Hall in the USA and Paul Héroux in France (1886) and based on the production of aluminum by electrolysis of alumina dissolved in molten cryolite, laid the foundation for the modern method of aluminum production. Since then, due to the improvement of electrical engineering, aluminum production has improved. The Russian scientists K. I. Bayer, D. A. Penyakov, A. N. Kuznetsov, E. I. Zhukovsky, and A. A. Yakovkin made a notable contribution to the development of alumina production. The first aluminum plant in Russia was built in 1932. year in the city of Volkhov. The metallurgical industry of the USSR in 1939 produced 47.7 thousand tons of aluminum, another 2.2 thousand tons were imported. Second World War significantly stimulated the production of aluminum. So, in 1939, its global production, excluding the USSR, was 620 thousand tons, but by 1943 it had grown to 1.9 million tons. By 1956, 3.4 million tons of primary aluminum were produced in the world, in 1965 - 5.4 million tons, in 1980 - 16.1 million tons, in 1990 - 18 million tons. In 2007, 38 million tons of primary aluminum were produced in the world, and in 2008 - 39.7 million tons. :

1. PRC China (in 2007 it produced 12.60 million tons, and in 2008 - 13.50 million tons)
2. Russia Russia (3.96/4.20)
3. Canada Canada (3.09/3.10)
4. US US (2.55/2.64)
5. Australia Australia (1.96/1.96)
6. Brazil Brazil (1.66/1.66)
7. India India (1.22/1.30)
8. Norway Norway (1.30/1.10)
9. UAE UAE (0.89/0.92)
10. Bahrain Bahrain (0.87/0.87)
11. South Africa South Africa (0.90/0.85)
12. Iceland Iceland (0.40/0.79)
13. Germany Germany (0.55/0.59)
14. Venezuela Venezuela (0.61/0.55)
15. Mozambique Mozambique (0.56/0.55)
16. Tajikistan Tajikistan (0.42/0.42)

In 2016, 59 million tons of aluminum were produced on the world market, the reserve is 2.224 million tons, and the average daily production is 128.6 thousand tons (2013.7). In Russia, the aluminum production monopoly is the Russian Aluminum company, which accounts for about 13% of the world aluminum market and 16% of alumina. The world reserves of bauxite are practically unlimited, that is, they are incommensurable with the dynamics of demand. Existing capacities can produce up to 44.3 million tons of primary aluminum per year. It should also be taken into account that in the future some of the aluminum applications may be reoriented to the use of, for example, composite materials. Prices for aluminum (at the auctions of international commodity exchanges) from 2007 to 2015 averaged 1253-3291 dollars per ton.

Application

Widely used as a structural material. The main advantages of aluminum in this capacity are lightness, ductility for stamping, corrosion resistance (in air, aluminum is instantly covered with a strong Al2O3 film, which prevents its further oxidation), high thermal conductivity, non-toxicity of its compounds. In particular, these properties have made aluminum extremely popular in the manufacture of cookware, aluminum foil in the food industry, and for packaging. The first three properties made aluminum the main raw material in the aviation and aerospace industry (recently it has been slowly replaced by composite materials, primarily carbon fiber). The main disadvantage of aluminum as a structural material is its low strength, therefore, to strengthen it, it is usually alloyed with a small amount of copper and magnesium (the alloy is called duralumin). The electrical conductivity of aluminum is only 1.7 times less than that of copper, while aluminum is approximately 4 times cheaper per kilogram, but, due to 3.3 times lower density, to obtain equal resistance, it needs approximately 2 times less weight . Therefore, it is widely used in electrical engineering for the manufacture of wires, their shielding, and even in microelectronics when deposition of conductors on the surface of microcircuit crystals. The lower electrical conductivity of aluminum (3.7 107 S/m) compared to copper (5.84 107 S/m), to maintain the same electrical resistance, is compensated by an increase in the cross-sectional area of ​​aluminum conductors. The disadvantage of aluminum as an electrical material is the formation of a strong dielectric oxide film on its surface, which makes soldering difficult and, due to the deterioration of contact resistance, causes increased heating at electrical connections, which, in turn, adversely affects the reliability of electrical contact and the state of insulation. Therefore, in particular, the 7th edition of the Electrical Installation Rules, adopted in 2002, prohibits the use of aluminum conductors with a cross section of less than 16 mm².

• Due to the complex of properties, it is widely used in thermal equipment.
• Aluminum and its alloys do not become brittle at ultra-low temperatures. Because of this, it is widely used in cryogenic technology. However, there is a known case of the acquisition of brittleness by cryogenic pipes made of aluminum alloy due to their bending on copper cores during the development of RN Energia.
• The high reflectivity, combined with the low cost and ease of vacuum deposition, makes aluminum the optimal material for making mirrors.
• In the production of building materials as a gas-forming agent.
• Aluminizing gives corrosion and scale resistance to steel and other alloys, for example, piston engine valves, turbine blades, oil platforms, heat exchange equipment, and also replaces galvanizing.
• Aluminum sulfide is used to produce hydrogen sulfide.
• Research is underway to develop foamed aluminum as a particularly strong and lightweight material.

As a restorer

• As a component of thermite, mixtures for aluminothermy.
• in pyrotechnics.
• Aluminum is used to recover rare metals from their oxides or halides.
• Limited use as a protector for anodic protection.

Aluminum based alloys

As a structural material, not pure aluminum is usually used, but various alloys based on it. The designation of the series of alloys in this article is given for the USA (standard H35.1 ANSI) and according to GOST Russia. In Russia, the main standards are GOST 1583 “Cast aluminum alloys. Specifications” and GOST 4784 “Aluminum and wrought aluminum alloys. Marks. There is also UNS marking and international standard for aluminum alloys and their marking ISO R209 b.

• Aluminum-magnesium Al-Mg (ANSI: 5xxx series for wrought alloys and 5xx.x for alloys for shaped castings; GOST: AMg). Alloys of the Al-Mg system are characterized by a combination of satisfactory strength, good ductility, very good weldability and corrosion resistance. In addition, these alloys are characterized by high vibration resistance.

In alloys of this system, containing up to 6% Mg, a eutectic system of Al3Mg2 joining with an aluminum-based solid solution is formed. The most widely used in industry are alloys with magnesium content from 1 to 5%. An increase in the Mg content in the alloy significantly increases its strength. Each percentage of magnesium increases the tensile strength of the alloy by 30 MPa, and the yield strength by 20 MPa. In this case, the relative elongation decreases slightly and is in the range of 30-35%. Alloys with a magnesium content of up to 3% (by mass) are structurally stable at room and elevated temperatures even in a significantly cold-worked state. As the concentration of magnesium in the work-hardened state increases, the structure of the alloy becomes unstable. In addition, an increase in the magnesium content above 6% leads to a deterioration in the corrosion resistance of the alloy. To improve the strength characteristics of the Al-Mg system alloys are alloyed with chromium, manganese, titanium, silicon or vanadium. They try to avoid the ingress of copper and iron into the alloys of this system, since they reduce their corrosion resistance and weldability.

• Aluminum-manganese Al-Mn (ANSI: 3xxx series; GOST: AMts). The alloys of this system have good strength, ductility and workability, high corrosion resistance and good weldability.

The main impurities in Al-Mn system alloys are iron and silicon. Both of these elements reduce the solubility of manganese in aluminum. To obtain a fine-grained structure, the alloys of this system are alloyed with titanium. The presence of a sufficient amount of manganese ensures the stability of the cold-worked metal structure at room and elevated temperatures.

• Aluminum-copper Al-Cu (Al-Cu-Mg) (ANSI: 2xxx series, 2xx.x; GOST: AM). The mechanical properties of the alloys of this system in the heat-strengthened state reach, and sometimes exceed, mechanical properties low carbon steels. These alloys are high tech. However, they also have a significant drawback - low corrosion resistance, which leads to the need to use protective coatings.

Manganese, silicon, iron and magnesium can be used as dopants. Moreover, the latter has the strongest influence on the properties of the alloy: alloying with magnesium significantly increases the tensile strength and yield strength. The addition of silicon to the alloy increases its ability to artificial aging. Alloying with iron and nickel increases the heat resistance of alloys of the second series. Work hardening of these alloys after quenching accelerates artificial aging, and also increases strength and resistance to stress corrosion.

• Alloys of the Al-Zn-Mg (Al-Zn-Mg-Cu) system (ANSI: 7xxx, 7xx.x series). The alloys of this system are valued for their very high strength and good workability. The representative of the system - alloy 7075 is the strongest of all aluminum alloys. The effect of such a high hardening is achieved due to the high solubility of zinc (70%) and magnesium (17.4%) at elevated temperatures, which sharply decreases upon cooling.

However, a significant disadvantage of these alloys is the extremely low stress corrosion resistance. The corrosion resistance of alloys under stress can be increased by alloying with copper. It is impossible not to note the regularity discovered in the 60s: the presence of lithium in alloys slows down natural and accelerates artificial aging. In addition, the presence of lithium reduces the specific gravity of the alloy and significantly increases its modulus of elasticity. As a result of this discovery, new Al-Mg-Li, Al-Cu-Li and Al-Mg-Cu-Li alloy systems have been developed.

• Aluminum-silicon alloys (silumins) are best suited for casting. Cases of various mechanisms are often cast from them.
• Complex alloys based on aluminum: aviation.

Aluminum as an additive in other alloys

Aluminum is an important component of many alloys. For example, in aluminum bronzes, the main components are copper and aluminum. In magnesium alloys, aluminum is most often used as an additive. For the manufacture of spirals in electric heaters, Fechral (Fe, Cr, Al) is used (along with other alloys). The addition of aluminum to the so-called "free-cutting steels" facilitates their processing, giving a clear breaking off of the finished part from the bar at the end of the process.

Jewelry

When aluminum was very expensive, a variety of jewelry was made from it. So, Napoleon III ordered aluminum buttons, and in 1889 Mendeleev was presented with scales with bowls made of gold and aluminum. The fashion for aluminum jewelry immediately disappeared when new technologies for its production appeared, which reduced the cost many times over. Now aluminum is sometimes used in the manufacture of jewelry. In Japan, aluminum is used in the manufacture of traditional jewelry, replacing silver.

Cutlery

By order of Napoleon III, aluminum cutlery was made, which was served at gala dinners to him and the most honored guests. Other guests at the same time used appliances made of gold and silver. Then aluminum cutlery became widespread, over time, the use of aluminum kitchen utensils decreased significantly, but even now they can still be seen only in some catering establishments - despite the statements of some experts about the harmfulness of aluminum to human health. In addition, such devices eventually lose their attractive appearance due to scratches and their shape due to the softness of aluminum. Utensils for the army are made of aluminum: spoons, bowlers, flasks.

Glassmaking

Fluoride, phosphate and aluminum oxide are used in glassmaking.

food industry

Aluminum is registered as food additive E173.

military industry

The cheapness and weight of the metal led to widespread use in the production of manual small arms especially assault rifles and pistols.

Aluminum and its compounds in rocketry

Aluminum and its compounds are used as a high performance propellant in bipropellant propellants and as a propellant in solid propellants. The following aluminum compounds are of the greatest practical interest as rocket fuel:

• Powdered aluminum as a fuel in solid rocket propellants. It is also used in the form of powder and suspensions in hydrocarbons.
• aluminum hydride.
• aluminum borane.
• Trimethylaluminum.
• Triethylaluminum.
• Tripropylaluminum.

Triethylaluminum (usually mixed with triethylboron) is also used for chemical ignition (as a starting fuel) in rocket engines, since it ignites spontaneously in oxygen gas. Aluminum hydride propellants, depending on the oxidizer, have the following characteristics:

Aluminum energy

Aluminum energy uses aluminum as a universal secondary energy carrier. Its applications in this capacity are:

• Oxidation of aluminum in water to produce hydrogen and thermal energy.
• Oxidation of aluminum with atmospheric oxygen for the production of electricity in air-aluminum electrochemical generators.

Aluminum in world culture

• In the novel by N. G. Chernyshevsky “What to do?” (1862-1863) one of the main characters describes his dream in a letter - a vision of the future in which people live, relax and work in multi-storey buildings made of glass and aluminum; floors, ceilings and furniture are made of aluminum (at the time of N. G. Chernyshevsky, aluminum was just beginning to be discovered).
• Aluminum Cucumbers is the image and title of Viktor Tsoi's 1987 song.

Toxicity

Despite its wide distribution in nature, not a single living being uses aluminum in metabolism - it is a dead metal. It has a slight toxic effect, but many water-soluble inorganic aluminum compounds remain in a dissolved state. long time and can have harmful effects on humans and warm-blooded animals through drinking water. The most toxic are chlorides, nitrates, acetates, sulfates, etc. For humans, the following doses of aluminum compounds (mg/kg of body weight) have a toxic effect when ingested:

• aluminum acetate - 0.2-0.4;
• aluminum hydroxide - 3.7-7.3;
• aluminum alum - 2.9.

Primarily acts on nervous system(accumulates in the nervous tissue, leading to severe disorders of the central nervous system function). However, the neurotoxic property of aluminum has been studied since the mid-1960s, since the accumulation of the metal in the human body is hindered by the mechanism of its excretion. Under normal conditions, up to 15 mg of an element per day can be excreted in the urine. Accordingly, the greatest negative effect is observed in people with impaired renal excretory function. The standard for aluminum content in drinking water in Russia is 0.2 mg/l. At the same time, this MPC can be increased to 0.5 mg/l by the chief state sanitary doctor for the relevant territory for a particular water supply system. According to some biological studies, the intake of aluminum in the human body was considered a factor in the development of Alzheimer's disease, but these studies were later criticized, and the conclusion about the connection of one with the other was refuted. Aluminum compounds may also stimulate breast cancer when aluminum chloride antiperspirants are used. But there is less scientific evidence to support this than to the contrary.

see also

• Anodizing
• Oxidation
• Aluminum. thirteenth element
• International Aluminum Institute

Notes

1. Michael E. Wieser, Norman Holden, Tyler B. Coplen, John K. Böhlke, Michael Berglund, Willi A. Brand, Paul De Bièvre, Manfred Gröning, Robert D. Loss, Juris Meija, Takafumi Hirata, Thomas Prohaska, Ronny Schoenberg, Glenda O'Connor, Thomas Walczyk, Shige Yoneda, Xiang‑Kun Zhu. Atomic weights of the elements 2011 (IUPAC Technical Report) // Pure and Applied Chemistry. - 2013. - Vol. 85, no. 5. - P. 1047-1078. - DOI:10.1351/PAC-REP-13-03-02.
2. Chemical encyclopedia. In 5 volumes / Ed.: Knunyants I. L. (Chief ed.). - M.: Soviet Encyclopedia, 1988. - T. 1. - S. 116. - 623 p. - 100,000 copies.
3. Harry H. Binder: Lexikon der chemischen Elemente. S. Hirzel Verlag, Stuttgart 1999, ISBN 3-7776-0736-3.
4. aluminium. Online Etymology Dictionary. etymonline.com. Retrieved May 3, 2010.
5. Fialkov, Yu. Ninth sign. - M.: Detgiz, 1963. - S. 133.
6. Lesson number 49
7. Aluminum Recycling and Processing for Energy Conservation and Sustainability. - ASM International, 2007. - P. 198. - ISBN 0-87170-859-0.
8. Brief chemical encyclopedia. T. 1 (A-E). - M.: Soviet Encyclopedia. 1961.
9. Koronovsky N. V., Yakushova A. F. Fundamentals of Geology.
10. Oleinikov B. V. et al. Aluminum is a new mineral of the class of native elements // Zapiski VMO. - 1984, part CXIII, no. 2, p. 210-215. .
11. J.P. Riley and Skirrow G. Chemical Oceanography V. 1, 1965.
12. Fundamentals of Hydrogen Energy / Ed. V. A. Moshnikov and E. I. Terukova .. - St. Petersburg: Publishing House of St. Petersburg Electrotechnical University "Leti", 2010. - 288 p. - ISBN 978-5-7629-1096-5.
13. Lidin R. A., Molochko V. A., Andreeva L. L. Reactions inorganic substances: reference book / Ed. R. A. Lidina. - 2nd ed., revised. and additional - M.: Bustard, 2007. - S. 16. - 637 p. - ISBN 978-5-358-01303-2.
14. Encyclopedia: jewelry, jewelry, jewelry stones. Precious metals. Precious aluminium.
15. "Silver" from clay.
16. MINERAL COMMODITY SUMMARIES 2009.
17. C34 Current state global and domestic production and consumption of aluminum
18. Aluminum reserves are growing in the world.
19. Production of primary aluminum in the world and in Russia.
20. Historical price chart for Aluminium. Retrieved June 8, 2015.
21. Kitco - Base Metals - Industrial metals - Copper, Aluminum, Nickel, Zinc, Lead - Charts, Prices, Graphs, Quotes, Cu, Ni, Zn, Al, Pb.
22. Effect of alloying elements on the properties of aluminum alloys.
23. Baykov D. I. and others. Weldable aluminum alloys. - L.: Sudpromgiz, 1959. - 236 p.
24. Facts about aluminum.
25. Assault rifle Heckler-Koch HK416 (Germany) | Economic news.
26. Tara Perfection D.O.O. - Safety you can depend on.
27. Sarner S. Chemistry of rocket fuels \u003d Propellant Chemistry / Per. from English. E. P. Golubkova, V. K. Starkov, V. N. Shemanina; ed. V. A. Ilyinsky. - M.: Mir, 1969. - S. 111. - 488 p.
28. Zhuk A. Z., Kleimenov B. V., Fortov V. E., Sheindlin A. E. Electric car on aluminum fuel. - M: Nauka, 2012. - 171 p. - ISBN 978-5-02-037984-8.
29. aluminum cucumbers
30. Shcherbatykh I., Carpenter D.O.(May 2007). The role of metals in the etiology of Alzheimer's disease // J. Alzheimers Dis. 11(2): 191-205.
31. Rondeau V., Commenges D., Jacqmin-Gadda H., Dartigues J. F.(July 2000). Relationship between aluminum concentrations in drinking water and Alzheimer’s disease: an 8-year follow-up study // Am. J. epidemiol. 152(1): 59-66.
32. Rondeau V.(2002). A review of epidemiologic studies on aluminum and silica in relation to Alzheimer's disease and associated disorders // Rev. Environ. Health 17(2): 107-121.
33. Martyn C. N., Coggon D. N., Inskip H., Lacey R. F., Young W. F.(May 1997). Aluminum concentrations in drinking water and risk of Alzheimer's disease // Epidemiology 8 (3): 281-286.
34. Graves A. B., Rosner D., Echeverria D., Mortimer J. A., Larson E. B.(September 1998). Occupational exposures to solvents and aluminum and estimated risk of Alzheimer's disease // Occup. Environ. Med. 55(9): 627-633.
35. Antiperspirants/Deodorants and Breast Cancer.
36. aluminum chloride hexahydrate.

Links

• Aluminum // encyclopedic Dictionary Brockhaus and Efron: in 86 volumes (82 volumes and 4 additional). - St. Petersburg, 1890-1907.
• Aluminum on Webelements
• Aluminum at the Popular Library of Chemical Elements
• Aluminum in deposits
• History, production and uses of aluminum
• Alekseev A. I., Valov M. Yu., Yuzvyak Z. Criteria for the quality of water systems: Tutorial. - St. Petersburg: KHIMIZDAT, 2002. ISBN 5-93808-043-6
• GN 2.1.5.1315-03 Maximum Permissible Concentrations (MPC) of chemicals in the water of water bodies for drinking and domestic water use.
• GOST R 55375-2012. Primary aluminum and alloys based on it. Stamps
• Documentary "Aluminum"

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Aluminum is one of the most popular and sought after metals. In which industry it is not added to the composition of certain items. Starting from instrumentation and ending with aviation. The properties of this light, flexible and non-corrosive metal came to the taste of quite a lot of industries.

Aluminum itself (a rather active metal) is practically never found in nature in its pure form and is mined from alumina, the chemical formula of which is Al 2 O 3. But the direct way to obtain alumina is, in turn, aluminum ore.

Saturation Differences

Basically, there are only three types of ores that you need to work with if you are mining aluminum. Yes, this chemical element is very, very common, and it can also be found in other compounds (there are about two and a half hundred of them). However, the most profitable, due to the very high concentration, will be extraction from bauxites, alunites and nephelines.

Nephelines are an alkaline formation that appeared as a result of high temperature magma. From one unit of this ore, up to 25% of alumina will be released as the main raw material. However, this aluminum ore is considered the poorest for miners. All compounds containing alumina in even smaller quantities than nephelines have are obviously recognized as unprofitable.

Alunites were formed during volcanic as well as hydrothermal activities. They contain up to 40% of such necessary alumina, being the "golden mean" in our trinity of ores.

And the first place, with a record content of aluminum oxide in the form of fifty percent or more, is received by bauxites! They are rightfully considered the main source of alumina. However, with regards to their origin, scientists still cannot come to the only right decision.

Either they migrated from their original place of origin and were deposited after the ancient rocks had weathered, or they turned out to be a sediment after some limestones dissolved, or they generally became the result of the decay of iron, aluminum and titanium salts, having precipitated. In general, the origin is still unknown. But the fact that bauxites are the most profitable is already certain.

Methods for extracting aluminum

The necessary ores are mined in two ways.

In terms of open-pit mining of the coveted Al 2 O 3 in aluminum deposits, the three main ores are divided into two groups.

Bauxite and nepheline, as higher density structures, are milled using a surface miner. Of course, it all depends on the manufacturer and model of the machine, but, on average, it is able to remove up to 60 centimeters of rock at a time. After a complete passage of one layer, the so-called shelf is made. This method contributes to the safe presence of the combine operator in his place. In the event of a collapse, both the undercarriage and the cab with the operator will be safe.

In the second group there are alunites, which, due to their looseness, are mined by mining excavators with subsequent unloading onto dump trucks.

A radically different way is to break through the mine. Here the principle of extraction is the same as in the coal mine. By the way, the deepest aluminum mine in Russia is the one located in the Urals. The depth of the mine is 1550m.!

Processing of obtained ore

Further, regardless of the chosen method of extraction, the obtained minerals are sent to processing workshops, where special crushers will break the minerals into fractions, about 110 millimeters in size.

The next step is to obtain additional chem. additives and transportation to the next stage, which is the sintering of the rock in furnaces.

Having passed the decomposition and having obtained aluminate pulp at the exit from it, we will send the pulp for separation and drying it from the liquid.

At the final stage, what happened is cleaned of alkalis and again sent to the furnace. This time - for calcination. The final of all actions will be the same dry alumina, which is needed to obtain aluminum through hydrolysis.

Although breaking through the mine is considered a more difficult way, but it does less harm. environment, how open method. If you are for the environment, you know what to choose.

Aluminum mining in the world

At this point, we can say that the indicators for interactions with aluminum around the world are divided into two lists. The first list will include countries that own the largest natural reserves of aluminum, but, perhaps, not all of these riches have time to process. And in the second list are the world leaders in the direct extraction of aluminum ore.

So, in terms of natural (although not everywhere, so far, realized) wealth, the situation is as follows:

1. Guinea
2. Brazil
3. Jamaica
4. Australia
5. India

These countries can be said to have the vast majority of Al 2 O 3 in the world. They account for 73 percent of the total. The rest of the reserves are scattered throughout the globe not in such generous amounts. Guinea, which is located in Africa, in a global sense - largest deposit aluminum ores in the world. She "cut off" 28%, which is even more than a quarter of the global deposits of this mineral.

And this is how things are with the processes of mining aluminum ore:

1. China is in first place and produces 86.5 million tons;
2. Australia is a country of outlandish animals with its 81.7 million. tons in second place;
3. Brazil - 30.7 million tons;
4. Guinea, being the leader in terms of reserves, is only in fourth place in terms of production - 19.7 million tons;
5. India - 14.9 million tons.

Also, Jamaica can be added to this list, capable of producing 9.7 million tons and Russia, with its figure of 6.6 million tons.

Aluminum in Russia

With regards to aluminum production in Russia, only the Leningrad Region and, of course, the Urals, as a true storehouse of minerals, can boast of certain indicators. The main method of extraction is mine. They mine four-fifths of all the country's ore. In total, on the territory of the Federation there are more than four dozen deposits of nepheline and bauxite, the resource of which will definitely be enough even for our great-great-grandchildren.

However, Russia also imports alumina from other countries. This is because local substances (for example, the Red Riding Hood deposit in Sverdlovsk region) contain only half of the alumina. Whereas Chinese or Italian breeds are saturated with Al 2 O 3 by sixty percent or more.

Looking back at some of the difficulties with aluminum mining in Russia, it makes sense to think about the production of secondary aluminum, as did the UK, Germany, USA, France and Japan.

Application of aluminum

As we already mentioned at the beginning of the article, the range of applications of aluminum and its compounds is extremely wide. Even at the stages of extraction from the rock, it is extremely useful. In the ore itself, for example, there are also small amounts of other metals, such as vanadium, titanium and chromium, useful for steel alloying processes. At the stage of alumina, there is also a benefit, because alumina is used in ferrous metallurgy as a flux.

The metal itself is used in the manufacture of thermal equipment, cryogenic technology, is involved in the creation of a number of alloys in metallurgy, is present in the glass industry, rocketry, aviation, and even in the food industry, as an additive E173.

So, only one thing is certain. For many more years, the need of mankind for aluminum, as well as for its compounds, will not fade away. Which, accordingly, speaks only about the growth of its production.

In modern industry, aluminum ore is the most demanded raw material. The rapid development of science and technology has expanded the scope of its application. What is aluminum ore and where it is mined is described in this article.

Industrial value of aluminum

Aluminum is considered the most common metal. By the number of deposits in the earth's crust, it ranks third. Aluminum is also known to everyone as an element in the periodic table, which belongs to light metals.

Aluminum ore is a natural raw material from which it is obtained. It is mainly mined from bauxites, which contain aluminum oxides (alumina) in the largest amount - from 28 to 80%. Other rocks - alunite, nepheline and nepheline-apatite are also used as raw materials for aluminum production, but they are of poorer quality and contain much less alumina.

In non-ferrous metallurgy, aluminum occupies the first place. The fact is that due to its characteristics it is used in many industries. So, this metal is used in transport engineering, packaging production, construction, for the manufacture of various consumer goods. Aluminum is also widely used in electrical engineering.

To understand the importance of aluminum for humanity, it is enough to take a closer look at the household items that we use every day. A lot of household items are made of aluminum: these are parts for electrical appliances (refrigerator, washing machine, etc.), dishes, sports equipment, souvenirs, interior elements. Aluminum is often used for the production of various types of containers and packaging. For example, cans or disposable foil containers.

Types of aluminum ores

Aluminum is found in more than 250 minerals. Of these, the most valuable for industry are bauxite, nepheline and alunite. Let's dwell on them in more detail.

bauxite ore

Aluminum is not found in nature in its pure form. It is mainly obtained from aluminum ore - bauxite. It is a mineral that mostly consists of aluminum hydroxides, as well as oxides of iron and silicon. Due to the high content of alumina (from 40 to 60%), bauxite is used as a raw material for the production of aluminum.

Physical properties of aluminum ore:

• opaque mineral of red and gray color of various shades;
• the hardness of the most durable samples is 6 on the mineralogical scale;
• the density of bauxites, depending on the chemical composition, ranges from 2900-3500 kg/m³.

Deposits of bauxite ore are concentrated in the equatorial and tropical zones of the earth. More ancient deposits are located on the territory of Russia.

How bauxite aluminum ore is formed

Bauxites are formed from monohydrate alumina hydrate, boehmite and diaspore, trihydrate hydrate - hydrargillite and accompanying minerals hydroxide and iron oxide.

Depending on the composition of nature-forming elements, there are three groups of bauxite ores:

1. Monohydrate bauxites - contain alumina in a monohydrate form.
2. Trihydrate - such minerals consist of alumina in a three-water form.
3. Mixed - this group includes the previous aluminum ores in combination.

Deposits of raw materials are formed as a result of the weathering of acidic, alkaline, and sometimes basic rocks, or as a result of the gradual deposition of a large amount of alumina on the sea and lake bottom.

Alunite ores

This type of deposits contains up to 40% aluminum oxide. Alunite ore is formed in the water basin and coastal zones under conditions of intense hydrothermal and volcanic activity. An example of such deposits is Lake Zaglinskoye in the Lesser Caucasus.

The breed is porous. It mainly consists of kaolinites and hydromicas. Of industrial interest are ore with an alunite content of more than 50%.

Nepheline

It is an aluminum ore of igneous origin. It is a full-crystalline alkaline rock. Depending on the composition and technological features of processing, several varieties of nepheline ore are distinguished:

• first grade - 60-90% nepheline; it contains more than 25% alumina; processing is carried out by sintering;
• the second grade - 40-60% nepheline, the amount of alumina is slightly lower - 22-25%; enrichment is required during processing;
• the third grade is nepheline minerals, which are of no industrial value.

World production of aluminum ores

For the first time, aluminum ore was mined in the first half of the 19th century in the south-east of France, near the town of Box. This is where the name bauxite comes from. At first, this development was slow. But when humanity appreciated what kind of aluminum ore is useful for production, the scope of aluminum has expanded significantly. Many countries have begun searching for deposits in their territories. Thus, the world production of aluminum ores began to gradually increase. The figures confirm this fact. So, if in 1913 the global volume of ore mined was 540 thousand tons, then in 2014 it was more than 180 million tons.

The number of countries producing aluminum ore also gradually increased. Today there are about 30 of them. But over the past 100 years, the leading countries and regions have been constantly changing. So, at the beginning of the 20th century, North America and Western Europe were the world leaders in the extraction of aluminum ore and its production. These two regions accounted for about 98% of global production. A few decades later, Latin America and the Soviet Union became leaders in terms of quantitative indicators of the aluminum industry. And already in the 1950s and 1960s, Latin America became the leader in terms of production. And in the 1980-1990s. there was a rapid breakthrough in aluminum and Africa. In the current global trend, the main aluminum mining countries are Australia, Brazil, China, Guinea, Jamaica, India, Russia, Suriname, Venezuela and Greece.

Ore deposits in Russia

In terms of production of aluminum ores, Russia ranks seventh in the world ranking. Although the deposits of aluminum ores in Russia provide the country with metal in large quantities, it is not enough to fully supply the industry. Therefore, the state is forced to buy bauxite in other countries.

In total, 50 ore deposits are located on the territory of Russia. This number includes both places where the mineral is being mined, and deposits that have not yet been developed.

Most of the ore reserves are located in the European part of the country. Here they are located in the Sverdlovsk, Arkhangelsk, Belgorod regions, in the Komi Republic. All these regions contain 70% of all explored ore reserves of the country.

Aluminum ores in Russia are still mined in old bauxite deposits. These areas include the Radynskoye field in the Leningrad region. Also, due to the shortage of raw materials, Russia uses other aluminum ores, the deposits of which are of the worst quality mineral deposits. But they are still suitable for industrial purposes. So, in Russia, nepheline ores are mined in large quantities, which also make it possible to obtain aluminum.