Aluminum ores. From mining to obtaining metal. Leading countries in aluminum production Which ores are used to produce aluminum

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

Industrial importance of aluminum

Aluminum is considered the most common metal. It ranks third in terms of the number of deposits in the earth's crust. 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 mainly mined from bauxite, which contains 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 the production of aluminum, but they are of poorer quality and contain significantly less alumina.

Aluminum ranks first in non-ferrous metallurgy. The fact is that due to its characteristics it is used in many industries. Thus, this metal is used in transport engineering, packaging production, construction, and 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 things that we use every day. Many 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 produce 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 look at them in more detail.

Bauxite ore

Aluminum does not occur 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 iron and silicon oxides. Due to the high alumina content (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 colors of various shades;
the hardness of the strongest samples is 6 on the mineralogical scale;
The density of bauxite, depending on the chemical composition, ranges from 2900-3500 kg/m³.

Bauxite ore deposits are concentrated in the equatorial and tropical zone land. More ancient deposits are located in Russia.

How is bauxite aluminum ore formed?

Bauxite is formed from alumina monohydrate, boehmite and diaspore, trihydrate hydrargillite and associated minerals hydroxide and iron oxide.

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

Monohydrate bauxite - contains alumina in monohydrate form.
Trihydrate - such minerals consist of alumina in trihydrate form.
Mixed - this group includes the previous aluminum ores in combination.

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

Alunite ores

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

The rock is porous. Mainly consists of kaolinites and hydromicas. Ore with an alunite content of more than 50% is of industrial interest.

Nepheline

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

first grade - 60-90% nepheline; it contains more than 25% alumina; processing is carried out by sintering;
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

Aluminum ore was first mined in the first half of the 19th century in the southeast of France, near the town of Box. This is where the name bauxite comes from. First this developed at a slow pace. But when humanity appreciated which aluminum ore was useful for production, the scope of aluminum application expanded significantly. Many countries have begun searching for deposits on their territories. Thus, the world production of aluminum ores began to gradually increase. The numbers confirm this fact. Thus, 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 mining aluminum ore also gradually increased. Today there are about 30 of them. But over the past 100 years, leading countries and regions have constantly changed. Thus, 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. Several decades later, in terms of quantitative indicators of the aluminum industry, Latin America and Soviet Union. And already in the 1950-1960s, 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 leading countries in aluminum production are Australia, Brazil, China, Guinea, Jamaica, India, Russia, Suriname, Venezuela and Greece.

Ore deposits in Russia

In terms of aluminum ore production, Russia ranks seventh in the world ranking. Although aluminum ore deposits 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 from other countries.

In total, there are 50 ore deposits in 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 Sverdlovsk, Arkhangelsk, Belgorod region, in the Komi Republic. All these regions contain 70% of the country's total proven ore reserves.

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

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Aluminum is a metal coated with a matte 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 rock component in the form of bauxite, alunite and nepheline.

Varieties of alumina-containing ores

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

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

Feature of the natural rock bauxite

Natural deposits of bauxite, nepheline, alunite, clay, and kaolin can serve as a source of raw materials. Bauxite is the most saturated with aluminum compounds. Clays and kaolins are the most common rocks with a significant alumina content. Deposits of these minerals are found on the surface of the earth. Bauxite in nature exists only in the form of a binary compound of metal with oxygen. This compound is extracted from natural mountain ore in the form of bauxite, consisting of oxides of several chemical elements: aluminum, potassium, sodium, magnesium, iron, titanium, silicon, phosphorus. Depending on the deposit, bauxite contains from 28 to 80% alumina. This is the main raw material for obtaining a unique metal. The quality of bauxite as an aluminum raw material depends on its alumina content. This determines the physical properties bauxite:

The mineral has a hidden crystalline structure or is in an amorphous state. Many minerals have hardened forms of hydrogels of simple or complex composition.
The color of bauxite at different mining locations 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 solid properties mineral. The strongest minerals have a hardness of 6 units on the scale accepted in mineralogy.
As a natural mineral, bauxite has a number of impurities, most often these are oxides of iron, calcium, magnesium, manganese, and impurities of titanium and phosphorus compounds.

Bauxites, kaolins, and clays contain impurities of other compounds, which are separated into separate industries during the processing of raw materials. Only in Russia do they use deposits with rock deposits that contain lower concentrations of alumina. Recently, alumina began to be obtained from nephelines, which, in addition to alumina, contain oxides of metals such as potassium, sodium, silicon and, no less valuable, alum stone, alunite.

Methods for processing aluminum containing minerals

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

Extraction of ore from developed deposits.
Primary processing of waste rocks in order to increase the concentration of alumina is an enrichment process.
Preparation of pure alumina, electrolytic reduction of aluminum from its oxides.

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

Alumina mining and beneficiation

Alumina or aluminum oxides do not exist in nature in their pure form. It is extracted from aluminum ores using hydrochemical methods. Aluminum ore deposits in deposits usually explode, 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), 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 advantageous.
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. The vessels are equipped with a steam jacket that maintains the required temperature. The steam pressure is maintained at 1.5-3.5 MPa until the aluminum compounds are completely transferred from the enriched rock to sodium aluminate in a superheated sodium hydroxide solution.
After cooling, the liquid undergoes a filtration stage, as a result of which solid sediment is separated and a supersaturated pure aluminate solution is obtained. By adding aluminum hydroxide residues from the previous cycle to the resulting solution, decomposition is accelerated.
For final drying of aluminum oxide hydrate, a calcination procedure is used.

Electrolytic production of pure aluminum

Pure aluminum is produced using a continuous process that produces calcined aluminum enters the electrolytic reduction stage. Modern electrolysers are a device consisting of the following parts:

Made of steel casing lined with coal blocks and slabs. During operation, a dense film of frozen electrolyte is formed on the surface of the bath body, protecting 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 installation.
Current is supplied to the aluminum melt through carbon blocks and embedded steel rods.
The anodes, suspended on an iron frame using steel pins, are provided with rods connected to a lifting mechanism. As combustion proceeds, the anode moves down, and the rods are used as an element for supplying current.
In workshops, electrolyzers are installed sequentially in several rows (two or four rows).

Additional purification of aluminum by refining

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

Bottom – refined 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 must exceed 3000 kg/m3.
The middle layer is a mixture of fluorides and chlorides of barium, calcium, and aluminum with a melting point of about 730 ° C.
Upper layer - pure refined aluminum a melt that dissolves in the anode layer and rises upward. It serves as the cathode in this circuit. The current is supplied by a graphite electrode.

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

Industrial importance of aluminum

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

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 look at them in more detail.

Bauxite ore

Physical properties of aluminum ore:

opaque mineral of red and gray colors of various shades;
the hardness of the strongest samples is 6 on the mineralogical scale;
The density of bauxite, depending on the chemical composition, ranges from 2900-3500 kg/m³.

Bauxite ore deposits are concentrated in the equatorial and tropical zones of the earth. More ancient deposits are located in Russia.

How is bauxite aluminum ore formed?

Bauxite is formed from alumina monohydrate, boehmite and diaspore, trihydrate hydrargillite and associated minerals hydroxide and iron oxide.

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

Monohydrate bauxite – contains alumina in monohydrate form.
Trihydrate - such minerals consist of alumina in trihydrate form.
Mixed - this group includes the previous aluminum ores in combination.

Alunite ores

The rock is porous. Mainly consists of kaolinites and hydromicas. Ore with an alunite content of more than 50% is of industrial interest.

Nepheline

first grade – 60–90% nepheline; it contains more than 25% alumina; processing is carried out by sintering;
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

Aluminum ore was first mined in the first half of the 19th century in the southeast of France, near the town of Box. This is where the name bauxite comes from. At first, this industry developed at a slow pace. But when humanity appreciated which aluminum ore was useful for production, the scope of aluminum application expanded significantly. Many countries have begun searching for deposits on their territories. Thus, the world production of aluminum ores began to gradually increase. The numbers confirm this fact. Thus, 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 mining aluminum ore also gradually increased. Today there are about 30 of them. But over the past 100 years, leading countries and regions have constantly changed. Thus, 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. After several decades, the countries became leaders in terms of quantitative indicators of the aluminum industry. of Eastern Europe, Latin America and the Soviet Union. And already in the 1950s–1960s, Latin America became the leader in terms of production. And in the 1980–1990s. There was a rapid breakthrough in the aluminum industry in Australia and Africa. In the current global trend, the main leading countries in aluminum production are Australia, Brazil, China, Guinea, Jamaica, India, Russia, Suriname, Venezuela and Greece.

Ore deposits in Russia

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

In total, there are 50 ore deposits in 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 the country's total proven ore reserves.

Bauxite is the main ore for aluminum production. The formation of deposits is associated with the process of weathering and transfer of material, which, in addition to aluminum hydroxides, also contains other chemical elements. Metal extraction technology provides a cost-effective process industrial production without generating waste.

Bauxite is the main ore for aluminum production

Characteristics of 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, and contains clay minerals, iron oxides and hydroxides as impurities.

By appearance Bauxite is a stony, or less commonly clay-like, rock that is uniform or layered in texture. Depending on the form of occurrence in the earth's crust, it can be dense or porous. Minerals are classified according to their structure:

clastic - conglomerate, gravel, sandstone, pelitic;
concretionary - legumes, oolitic.

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

The main minerals for ore formation are:

diaspora;
hydrogoethite;
goethite;
boehmite;
gibbsite;
kaolinite;
ilmenite;
aluminohematite;
calcite;
siderite;
mica.

There are bauxites of platform, geosynclinal and oceanic islands. Aluminum ore deposits were formed as a result of the transport of weathering products of rocks, followed by their deposition and the formation of sediment.

Industrial bauxite contains 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 industrial aluminum production in the Russian Federation are bauxite, nepheline ores and their concentrates, concentrated on the Kola Peninsula.

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

The main production of bauxite is carried out by JSC Sevuralboxytruda. 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.

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

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

Bauxite is mined by open and underground methods. Technological process processing of raw materials depends on its chemical composition and involves phased implementation of work.

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

Several methods are used to form alumina:

sintering;
hydrochemical;
combined.

The application of methods depends on the concentration of aluminum in the ore. Low quality bauxite is processed in a complex way. The mixture of soda, limestone and bauxite obtained as a result of sintering 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)

Application of mineral resource

The use of bauxite in various branches of industrial production is due to the versatility of the raw material in 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 when smelting open-hearth steel improves specifications products.

In the production of electrocorundum, the properties of bauxite are used to form a super-resistant, fire-resistant material (synthetic corundum) as a result of smelting 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 fire-resistant, quick-hardening cements. In addition to aluminum, iron, titanium, gallium, zirconium, chromium, niobium and TR (rare earth elements) are extracted from ore raw materials.

Bauxite is used for the production of paints, abrasives, and sorbents. Ore with a low iron content is used in the manufacture of refractory compounds.

Aluminum ore has gained the most popularity in modern industry. Aluminum is the most common metal of all metals existing on earth today. In addition, it holds 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 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 mechanical engineering, automotive, construction, in the production of various containers and packaging, electrical equipment, and other consumer goods. Almost every household appliance used by humans every day contains aluminum in one quantity or another.

Aluminum mining

There are a huge number of minerals in which the presence of this metal was once discovered. Scientists have concluded that this metal can be extracted from more than 250 minerals. However, it is not profitable to extract metal from absolutely all ores, therefore, among all the existing variety, there are the most valuable aluminum ores, from which the metal is obtained. These are: bauxite, nepheline, and alunite. Of all aluminum ores, the maximum aluminum content is found in bauxite. They contain about 50% of aluminum oxides. 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 rated 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% of alumina, which is the main raw material for the production of aluminum. It is worth saying that equatorial and tropical earth belts are the main area famous for its bauxite ore deposits. For the nucleation of bauxite, the participation of several components is necessary, including monohydrate alumina hydrate, boehmite, diaspore, as well as 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 alumina, aluminum turns out to be half as much - 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, can contain from 22% to 25% alumina. While alunites are slightly inferior to bauxites, and consist of 40% aluminum oxide.

Aluminum ores of Russia

The Russian Federation is ranked 7th among all countries in the world in terms of the amount of aluminum ore mined. It is worth noting that this raw material is in the territory Russian state is mined in colossal quantities. However, the country is experiencing a significant shortage of this metal, and is not able to provide it in the volume necessary to absolutely supply the industry. This is the priority 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 are 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 bauxite, which since ancient times has been the main and irreplaceable material from which aluminum is subsequently produced.

Aluminum production in Russia

At the beginning of the twentieth century, the emergence of the aluminum industry took place in Russia. It was in 1932 that the first aluminum production plant appeared in Volkhov. And already on May 14 of the same year, the company managed to receive a batch of metal for the first time. Every year, new aluminum ore deposits 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 manufactured goods, the main material for which was aluminum alloys. At the same time, the Pikalevsky alumina plant was put into operation. Russia is famous for its variety of factories, thanks to which the country produces aluminum. Of these, UC Rusal is considered the largest, not only within the Russian state, but throughout the world. He managed to produce about 3.603 million tons of aluminum in 2015, and in 2012 the company reached 4.173 million tons of metal.



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, 933.5 K
2518.82 °C, 2792 K
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 character

Indicating that aluminum can be recycled Aluminum- element of the 13th group of the periodic table of chemical elements (according to the outdated classification - an element of the main subgroup Group III), third period, with atomic number 13. Denoted by the symbol Al (lat. Aluminum). Belongs to the group of light metals. The most common metal and the third most abundant chemical element in the earth's crust (after oxygen and silicon). Simple substance aluminum- a lightweight paramagnetic metal of silver-white color, easy to form, cast, and machine. Aluminum has high thermal and electrical conductivity and 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. aluminum- alum. Before the discovery of an industrial method for producing aluminum, this metal was more expensive than gold. In 1889, the British, wanting 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, recovery of aluminum from ore is more difficult due to its high reactivity and high temperature smelting most of its ores (such as bauxite). Direct reduction with carbon cannot be used because the reducing power of aluminum is higher than that of carbon. Indirect reduction is possible to obtain the intermediate product Al4C3, which undergoes decomposition at 1900-2000 °C to form aluminum. This method is under development, but appears to be more profitable than the Hall-Heroult process, since it requires less energy and leads to the formation of less CO2. Modern method obtaining, the Hall-Héroult process was developed independently by the American Charles Hall and the Frenchman Paul Héroult in 1886. It consists of dissolving aluminum oxide Al2O3 in molten cryolite Na3AlF6, followed by electrolysis using consumable coke or graphite anode electrodes. This production method requires very large amounts of electricity, and therefore received industrial application only in the 20th century. To produce 1000 kg of crude aluminum, 1920 kg of alumina, 65 kg of cryolite, 35 kg of aluminum fluoride, 600 kg of anode graphite electrodes and about 17 MWh of electricity (~61 GJ) are required. A laboratory method for producing aluminum was proposed by Friedrich Wöhler in 1827 by reducing anhydrous aluminum chloride with potassium metal (the reaction occurs when heated without access to air):

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

Physical properties

Microstructure of aluminum on the etched surface of an ingot, 99.9998% purity, visible sector size about 55×37 mm

Silver-white metal, lightweight
density - 2712 kg/m³
the melting point of technical aluminum is 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: technical - 35%, pure - 50%, rolled into thin sheets 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, and has high light reflectivity.
Weak paramagnetic.
Temperature coefficient of linear expansion 24.58·10−6 K−1 (20…200 °C).
Specific resistance 0.0262..0.0295 Ohm mm²/m
Temperature coefficient of electrical resistance 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 alloys are copper and magnesium (duralumin) and silicon (silumin).

Being in nature

Prevalence

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

Natural aluminum compounds

In nature, aluminum, due to its high chemical activity, is found almost exclusively in the form of compounds. Some of the natural minerals of aluminum are:

Bauxite - Al2O3 H2O (with impurities 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 (volcano vents) negligible amounts of native metallic aluminum have been found. Natural waters contain aluminum in the form of low-toxic chemical compounds, for example, 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 a single 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 40Ar nuclei by protons of high-energy cosmic rays.

Chemical properties

Under normal conditions, aluminum is covered with a thin and durable oxide film and therefore does not react with classical oxidizing agents: H2O, O2, HNO3 (without heating), H2SO4, but reacts with HCl. Thanks to this, aluminum is practically not subject to corrosion and is therefore widely in demand in 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. You can prevent the formation of an oxide film by adding metals such as gallium, indium or tin to aluminum. In this case, the aluminum surface is wetted by low-melting eutectics based on these metals. Reacts easily with simple substances:

with oxygen, forming aluminum oxide:

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

with halogens (except fluorine), forming aluminum chloride, bromide or 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 to form 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 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 dissolves 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)))

reduces 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. (The assertion, sometimes found with reference to Pliny's Natural History, that aluminum was known under the Emperor Tiberius, is based on an incorrect interpretation of the source). In 1825, the Danish physicist Hans Christian Oersted obtained several milligrams of aluminum metal, and in 1827 Friedrich Wöhler was able to isolate grains of aluminum, which, however, were immediately covered in air with a thin film of aluminum oxide. Before late XIX century, aluminum was not produced on an industrial scale. Only in 1854, Henri Saint-Clair Deville (his research was funded by Napoleon III, hoping that aluminum would be useful to his army) invented the first method of industrial production of aluminum, based on the displacement of aluminum by metallic sodium from double sodium chloride and aluminum NaCl AlCl3. In 1855, the first metal ingot weighing 6-8 kg was obtained. Over 36 years of use, from 1855 to 1890, 200 tons of aluminum metal were produced using the Saint-Clair Deville method. In 1856, he also obtained aluminum by electrolysis of a molten sodium-aluminum chloride. In 1885, an aluminum production plant was built in the German city of Gmelingem, using technology proposed by Nikolai Beketov. Beketov’s technology was not much different from Deville’s method, but it was simpler and involved the interaction between cryolite (Na3AlF6) and magnesium. Over five years, this plant produced about 58 tons of aluminum - more than a quarter of the total global production of the 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 improvements in electrical engineering, aluminum production has improved. A notable contribution to the development of alumina production was made by Russian scientists K. I. Bayer, D. A. Penyakov, A. N. Kuznetsov, E. I. Zhukovsky, A. A. Yakovkin and others. The first aluminum smelter 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. World War II greatly stimulated aluminum production. Thus, 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. The leaders in production were :

China PRC (produced 12.60 million tons in 2007, and 13.50 million tons in 2008)
Russia Russia (3.96/4.20)
Canada Canada (3.09/3.10)
USA USA (2.55/2.64)
Australia Australia (1.96/1.96)
Brazil Brazil (1.66/1.66)
India India (1.22/1.30)
Norway Norway (1.30/1.10)
UAE UAE (0.89/0.92)
Bahrain Bahrain (0.87/0.87)
South Africa South Africa (0.90/0.85)
Iceland Iceland (0.40/0.79)
Germany Germany (0.55/0.59)
Venezuela Venezuela (0.61/0.55)
Mozambique Mozambique (0.56/0.55)
Tajikistan Tajikistan (0.42/0.42)

In 2016, 59 million tons of aluminum were produced on the world market, the stock is 2.224 million tons, and the average daily production is 128.6 thousand tons (2013.7). In Russia, the monopolist in aluminum production is the Russian Aluminum company, which accounts for about 13% of the global aluminum market and 16% of alumina. The world's reserves of bauxite are practically limitless, that is, they are incommensurate with the dynamics of demand. Existing facilities 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 applications of aluminum may be reoriented to the use of, for example, composite materials. Aluminum prices (at trading on international commodity exchanges) from 2007 to 2015 averaged $1253-3291 per ton.

Application

Widely used as a construction material. The main advantages of aluminum in this quality are lightness, malleability for stamping, corrosion resistance (in air, aluminum is instantly covered with a durable Al2O3 film, which prevents its further oxidation), high thermal conductivity, and non-toxicity of its compounds. In particular, these properties have made aluminum extremely popular in the production 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 industries (in Lately is slowly being replaced by composite materials, primarily carbon fiber). The main disadvantage of aluminum as a structural material is its low strength, so 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 its 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 depositing 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), in order to maintain the same electrical resistance, is compensated by increasing the cross-sectional area of the 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 the electrical connections, which, in turn, negatively affects the reliability of the electrical contact and the condition of the 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 its complex of properties, it is widely used in heating equipment.
Aluminum and its alloys do not become brittle at ultra-low temperatures. Due to this, it is widely used in cryogenic technology. However, there is a known case of cryogenic pipes made of aluminum alloy becoming brittle due to their bending on copper cores during the development of the Energia launch vehicle.
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 imparts corrosion and scale resistance to steel and other alloys, for example, valves of piston internal combustion engines, 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 an especially strong and lightweight material.

As a reducing agent

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 alloys

The structural material usually used is not pure aluminum, but various alloys based on it. The designation of alloy series in this article is given for the USA (H35.1 ANSI standard) and in accordance with Russian GOST. In Russia, the main standards are GOST 1583 “Cast aluminum alloys. Specifications" and GOST 4784 "Aluminum and deformable aluminum alloys. Stamps." There is also UNS marking and an international standard for aluminum alloys and their marking ISO R209 b.

Aluminum-magnesium Al-Mg (ANSI: series 5xxx 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 compound with an aluminum-based solid solution is formed. The most widely used in industry are alloys containing magnesium 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 weight) are structurally stable at room and elevated temperatures, even in a significantly hardened state. With increasing concentration of magnesium in the cold-worked state, the structure of the alloy becomes unstable. In addition, an increase in magnesium content above 6% leads to a deterioration in the corrosion resistance of the alloy. To improve the strength characteristics, Al-Mg system alloys are alloyed with chromium, manganese, titanium, silicon or vanadium. They try to avoid the inclusion of copper and iron in the alloys of this system, since they reduce their corrosion resistance and weldability.

Aluminum-manganese Al-Mn (ANSI: series 3xxx; GOST: AMts). Alloys of this system have good strength, ductility and manufacturability, 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 structure of the cold-worked metal at room and elevated temperatures.

Aluminum-copper Al-Cu (Al-Cu-Mg) (ANSI: series 2xxx, 2xx.x; GOST: AM). The mechanical properties of alloys of this system in a heat-strengthened state reach, and sometimes exceed, the mechanical properties of 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 alloying additives. And most strong influence The latter has an effect on the properties of the alloy: alloying with magnesium significantly increases the strength and yield limits. The addition of silicon to the alloy increases its ability to undergo artificial aging. Alloying with iron and nickel increases the heat resistance of alloys of the second series. Cold-hardening of these alloys after quenching accelerates artificial aging and also increases strength and stress corrosion resistance.

Al-Zn-Mg (Al-Zn-Mg-Cu) system alloys (ANSI: 7xxx, 7xx.x series). Alloys of this system are valued for their very high strength and good manufacturability. The representative of the system - alloy 7075 is the strongest of all aluminum alloys. The effect of such 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 their extremely low stress corrosion resistance. The corrosion resistance of stress alloys can be increased by alloying with copper. It is impossible not to note a pattern discovered in the 60s: the presence of lithium in alloys slows down natural aging and accelerates artificial aging. In addition, the presence of lithium reduces the specific gravity of the alloy and significantly increases its elastic modulus. As a result of this discovery, new alloy systems Al-Mg-Li, Al-Cu-Li and Al-Mg-Cu-Li were developed.

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

Aluminum as an additive to 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 heating devices, fechral (Fe, Cr, Al) is used (along with other alloys). The addition of aluminum to the so-called “free-cut steels” facilitates their processing, giving a clear breaking 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. Thus, Napoleon III ordered aluminum buttons, and in 1889 Mendeleev was presented with scales with bowls made of gold and aluminum. The fashion for jewelry made of aluminum immediately passed when new technologies for its production appeared, reducing the cost many times over. Nowadays, aluminum is sometimes used in the production of costume jewelry. In Japan, aluminum is used in the production of traditional jewelry, replacing silver.

Cutlery

By order of Napoleon III, aluminum cutlery was made, which was served at ceremonial dinners for him and the most honored guests. Other guests used gold and silver utensils. Then cutlery made of aluminum 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 statements by some experts about the harmfulness of aluminum to human health. In addition, such devices over time lose their attractive appearance due to scratches and their shape due to the softness of aluminum. Utensils for the army are made from aluminum: spoons, pots, flasks.

Glass making

Fluoride, phosphate and aluminum oxide are used in glass making.

Food industry

Aluminum is registered as food additives E173.

Military industry

The cheapness and weight of the metal have led to its widespread use in the production of hand-made small arms, in particular machine guns and pistols.

Aluminum and its compounds in rocket technology

Aluminum and its compounds are used as a highly efficient propellant in two-propellant rocket propellants and as a combustible component in solid rocket propellants. The following aluminum compounds are of greatest practical interest as rocket fuel:

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

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

Aluminum energy

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

Oxidation of aluminum in water to produce hydrogen and thermal energy.
Oxidation of aluminum with atmospheric oxygen to produce 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 in a letter his dream - a vision of the future in which people live, relax and work in multi-story buildings made of glass and aluminum; The floors, ceilings and furniture are made of aluminum (at the time of N.G. Chernyshevsky, aluminum was just beginning to be discovered).
Aluminum cucumbers are the image and title of a 1987 song by Viktor Tsoi.

Toxicity

Despite its widespread occurrence in nature, not a single living creature 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 for a long time and can have a harmful effect 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 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 affects nervous system(accumulates in nervous tissue, leading to severe disorders of the central nervous system). However, the neurotoxicity of aluminum has been studied since the mid-1960s, since the accumulation of the metal in the human body is prevented by its elimination mechanism. Under normal conditions, up to 15 mg of the 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. In this case, this MPC can be increased to 0.5 mg/l by the chief state sanitary doctor for the relevant territory for a specific water supply system. Some biological studies have implicated aluminum intake as a factor in the development of Alzheimer's disease, but these studies were later criticized and the link between the two was refuted. Aluminum compounds also may stimulate breast cancer when using aluminum chloride antiperspirants. But there is less scientific evidence to support this than to the contrary.

Notes

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.
Chemical encyclopedia. In 5 volumes / Editorial Board: Knunyants I. L. (chief editor). - M.: Soviet encyclopedia, 1988. - T. 1. - P. 116. - 623 p. - 100,000 copies.
Harry H. Binder: Lexikon der chemischen Elemente. S. Hirzel Verlag, Stuttgart 1999, ISBN 3-7776-0736-3.
aluminum Online Etymology Dictionary. etymonline.com. Retrieved May 3, 2010.
Fialkov, Yu. Ninth sign. - M.: Detgiz, 1963. - P. 133.
Lesson No. 49. Aluminum.
Aluminum Recycling and Processing for Energy Conservation and Sustainability. - ASM International, 2007. - P. 198. - ISBN 0-87170-859-0.
Brief chemical encyclopedia. T. 1 (A-E). - M.: Soviet Encyclopedia. 1961.
Koronovsky N.V., Yakushova A.F. Fundamentals of Geology.
Oleynikov B.V. et al. Aluminum is a new mineral of the class of native elements //Notes of the WMO. - 1984, part CXIII, issue. 2, p. 210-215. .
J.P. Riley and Skirrow G. Chemical Oceanography V. 1, 1965.
Fundamentals of hydrogen energy / Ed. V. A. Moshnikova and E. I. Terukova.. - St. Petersburg: Publishing house of St. Petersburg State Electrotechnical University "Leti", 2010. - 288 p. - ISBN 978-5-7629-1096-5.
Lidin R. A., Molochko V. A., Andreeva L. L. Reactions of inorganic substances: a reference book / Ed. R. A. Lidina. - 2nd ed., revised. and additional - M.: Bustard, 2007. - P. 16. - 637 p. - ISBN 978-5-358-01303-2.
Encyclopedia: jewelry, jewelry, jewelry stones. Precious metals. Precious aluminum.
"Silver" from clay.
MINERAL COMMODITY SUMMARIES 2009.
C34 Current state global and domestic aluminum production and consumption
Aluminum reserves are growing around the world.
Production of primary aluminum in the world and in Russia.
Historical price graph for Aluminum. Retrieved June 8, 2015.
Kitco - Base Metals - Industrial metals - Copper, Aluminum, Nickel, Zinc, Lead - Charts, Prices, Graphs, Quotes, Cu, Ni, Zn, Al, Pb.
The influence of alloying elements on the properties of aluminum alloys.
Baykov D.I. et al. Weldable aluminum alloys. - L.: Sudpromgiz, 1959. - 236 p.
Facts about aluminum.
Assault rifle Heckler-Koch HK416 (Germany) | Economic news.
Tara Perfection D.O.O. - Safety you can depend on.
Sarner S. Chemistry of rocket fuels = Propellant Chemistry / Transl. from English E. P. Golubkova, V. K. Starkova, V. N. Shemanina; edited by V. A. Ilyinsky. - M.: Mir, 1969. - P. 111. - 488 p.
Zhuk A. Z., Kleymenov B. V., Fortov V. E., Sheindlin A. E. Electric car running on aluminum fuel. - M: Nauka, 2012. - 171 p. - ISBN 978-5-02-037984-8.
Aluminum cucumbers
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Antiperspirants/Deodorants and Breast Cancer.
aluminum chloride hexahydrate.

Links

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

Eu, Sm, Li, Cs, Rb, K, Ra, Ba, Sr, Ca, Na, Ac, La, Ce, Pr, Nd, Pm, Gd, Tb, Mg, Y, Dy, Am, Ho, Er, Tm, Lu, Sc, Pu,
Th, Np, U, Hf, Be, Al, Ti, Zr, Yb, Mn, V, Nb, Pa, Cr, Zn, Ga, Fe, Cd, In, Tl, Co, Ni, Te, Mo, Sn, Pb, H2,
W, Sb, Bi, Ge, Re, Cu, Tc, Te, Rh, Po, Hg, Ag, Pd, Os, Ir, Pt, Au

And some other elements. However, not all of these elements are currently extracted from aluminum ores and used for the needs of the national economy.

The most fully used is apatite-nepheline rock, from which fertilizers, alumina, soda, potash, and some other products are obtained; there are almost no dumps.

When processing bauxite using the Bayer method or by sintering, a lot of red mud still remains in the dump, the rational use of which deserves great attention.

Earlier it was said that to produce 1 ton of aluminum it is necessary to spend a lot of electricity, which is a fifth of the cost of aluminum. In table 55 shows the cost calculation for 1 ton of aluminum. From the data given in the table, it follows that the most important components of cost are raw materials and basic materials, with alumina accounting for almost half of all costs. Therefore, reducing the cost of aluminum should primarily go in the direction of reducing the cost of alumina production.

Theoretically, 1.89 tons of alumina must be consumed for 1 ton of aluminum. Exceeding this value at actual consumption is a consequence of losses mainly from atomization. These losses can be reduced by 0.5-0.6% by automating the loading of alumina into the baths. Cost reductionalumina can be achieved by reducing losses at all stages of its production, especially in waste sludge, during transportation of aluminate solutions and, as well as during the calcination of alumina; due to savings obtained from better use of exhaust steam (from self-evaporators) and full use of waste gas heat. This is especially important for the autoclave method, where steam costs are significant.

Introduction of continuous leaching and twisting on; advanced alumina refineries made it possible to automate many operations, which helped reduce steam and electricity consumption, increase labor productivity and reduce the cost of aluminum. However, much more can be done in this direction. Without giving up further searches for high-grade bauxites, the transition to which will sharply reduce the cost of alumina, we should look for ways to comprehensively use ferruginous bauxites and red mud in ferrous metallurgy. An example is the complex use of apatite-nepheline rocks.

The cost of fluoride salts is 8%. They can be reduced by carefully removing gases from electrolyte baths and trapping fluoride compounds from them. Anode gases sucked out of the bath contain up to 40 mg/m 3 of fluorine, about 100 mg/m 3 of resin and 90 mg/m 3 of dust (AlF 3 , Al 2 O 3, Na 3 AlF 6). These gases must not be released into the atmosphere,since they contain valuable, in addition, they are poisonous. They must be cleaned of valuable dust and also rendered harmless in order to avoid poisoning the atmosphere of the workshop and areas adjacent to the plant. For purification purposes, gases are washed with weak soda solutions in tower gas purifiers (scrubbers).

With the perfect organization of purification and neutralization processes, it becomes possible to return part of the fluoride salts (up to 50%) to production and thereby reduce the cost of aluminum by 3-5%.

A significant reduction in the cost of aluminum can be achieved through the use of cheaper sources of electricity and the rapid widespread introduction of more economical semiconductor current converters (especially silicon ones), as well as by reducing energy consumption directly. The latter can be achieved by designing more advanced baths with less voltage loss in all or individual of their elements, as well as by selecting more electrically conductive electrolytes (the resistance of cryolite is too high and a huge amount of electricity turns into excess heat, which cannot yet be used rationally). And it is no coincidence that baths with baked anodes are beginning to find more and more use, since the energy consumption in these baths is much lower.

The maintenance personnel of electrolysis workshops play a major role in reducing energy consumption. Maintaining a normal pole-to-pole distance, keeping electrical contacts clean in various places in the bath, reducing the number and duration of anode effects, maintaining normal temperature electrolyte, careful monitoring of the composition of the electrolyte makes it possible to significantly reduce energy consumption.

Advanced teams of electrolysis shops of aluminum smelters, having studied the theoretical foundations of the process and the features of the baths they serve, carefully monitoring the progress of the process, have the opportunity to increase the amount of metal produced per unit of consumed electricity with excellent quality and, therefore, increase the efficiency of aluminum production.

The most important factor in reducing costs and increasing labor productivity is the mechanization of labor-intensive processes in the electrolysis shops of aluminum smelters. In this area, significant progress has been achieved at domestic aluminum smelters over the past decades: the extraction of aluminum from baths has been mechanized; Efficient and convenient mechanisms have been introduced for punching the electrolyte crust and removing and driving in the pins. However, it is necessary and possibleto a greater extent mechanize and automate processes at aluminum smelters. This is facilitated by a further increase in the power of electrolyzers and the transition from periodic processes to continuous ones.

IN last years The integrated use of aluminum ores has improved as some aluminum smelters have begun to extract vanadium oxides and gallium metal from waste.

It was discovered in 1875 by the spectral method. Four years earlier, D.I. Mendeleev predicted its basic properties with great accuracy (calling it eka-aluminum). has a silvery white color and low temperature melting (+30° C). A small piece of gallium can be melted into the palm of your hand. Along with this, the boiling point of gallium is quite high (2230°C), so it is used for high-temperature thermometers. Such thermometers with quartz tubes are applicable up to 1300° C. Gallium is close to lead in hardness. The density of solid gallium is 5.9 g/cm3, liquid gallium is 6.09 g/cm3.

Gallium is scattered in nature, the rich ones are unknown. It is found in hundredths and thousandths of a percent in aluminum ores, zinc blende and the ash of some coals. Gas plant resins sometimes contain up to 0.75% gallium.

Gallium is significantly more toxic than and, therefore all work on its extraction should be carried out observing careful hygiene.

In dry air at ordinary temperatures, gallium almost does not oxidize: when heated, it vigorously combines with oxygen, forming the white oxide Ga 2 O 3. Along with this gallium oxide, under certain conditions, other gallium oxides (GaO and Ga 2 O) are also formed. Gallium hydroxide Ga(OH) 3 is amphoteric and therefore easily soluble in acids and alkalis, with which it forms gallates, which are similar in properties to aluminates. In this regard, when producing alumina from aluminum ores, gallium, together with aluminum, goes into solutions and then accompanies it in all subsequent operations. Some increased concentration of gallium is observed in the anode alloy during the electrolytic refining of aluminum, in circulating aluminate solutions during the production of alumina using the Bayer method, and in mother liquors remaining after incomplete carbonization of aluminate solutions.

Therefore, without disturbing the redistribution scheme, it is possible to organize the extraction of gallium in the alumina and refining shops of aluminum smelters. Recycled aluminate solutions for gallium extraction can be periodically carbonized in two steps. First, during slow carbonization, approximately 90% of the aluminum is precipitated and the solution is filtered, which is then carbonized again in order to precipitate the gallium and remaining in solution in the form of hydroxides. The precipitate obtained in this way can contain up to 1.0% Ga 2 O 3 .

A significant portion of aluminum can be precipitated from the aluminate mother liquor in the form of fluoride salts. To do this, hydrofluoric acid is mixed into an aluminate solution containing gallium. At pH<2,5 из раствора осаждается значительная часть алюминия в виде фторида и криолита (Na 3 AlF 6). Галлий и часть алюминия остаются в растворе.

When an acidic solution is neutralized with soda to pH = 6, gallium and .

Further separation of aluminum from gallium can be achievedheat by treating aluminum-gallium hydrate sediments in an autoclave with lime milk containing a small amount of sodium hydroxide; in this case, gallium goes into solution,and the bulk of the aluminum remains in the sediment. Gallium is then precipitated from solution with carbon dioxide. The resulting precipitate contains up to 25% Ga 2 O 3. This precipitate is dissolved in caustic soda at a caustic ratio of 1.7 and treated with Na 2 S to remove heavy metals, especially lead. The purified and clarified solution is subjected to electrolysis at 60-75° C, a voltage of 3-5 V and constant stirring of the electrolyte. Cathodes and anodes must be made of stainless steel.

Other methods for concentrating gallium oxide from aluminate solutions are also known. Thus, from the anodic alloy containing 0.1-0.3% gallium remaining after electrolytic refining of aluminum using the three-layer method, the latter can be isolated by treating the alloy with a hot alkali solution. In this case, gallium goes into solution and remains in the sediment.

To obtain pure gallium compounds, the ability of gallium chloride to dissolve in ether is used.

If present in aluminum ores, it will constantly accumulate in aluminate solutions and, with a content of more than 0.5 g/l V 2 O 5, will precipitate with aluminum hydrate during carbonization and contaminate aluminum. To remove vanadium, the mother liquors are evaporated to a density of 1.33 g/cm 3 and cooled to 30 ° C, and a sludge containing more than 5% V 2 O 5 falls out, along with soda and other alkaline compounds of phosphorus and arsenic, from which it can be isolated first by complex hydrochemical processing and then by electrolysis of an aqueous solution.

Melting aluminum due to its high heat capacity and latent heat of fusion (392 J/g) requires high energy consumption. Therefore, the experience of electrolysis plants that began producing strip and wire rod directly from liquid aluminum (without casting into ingots) deserves to be disseminated. In addition, a great economic effect can be obtained from the production of various alloys for mass consumption from liquid aluminum in the foundries of electrolysis plants, and

Gallium history of the discovery of the element About the element with atomic number 31, most readers only remember that it is one of three elements...

Bauxite is the main ore for aluminum production. The formation of deposits is associated with the process of weathering and transfer of material, which, in addition to aluminum hydroxides, also contains other chemical elements. Metal extraction technology provides a cost-effective industrial production process without generating waste.

Characteristics of ore mineral

In appearance, bauxite is stony, and less often clay-like, the rock is homogeneous or layered in texture. Depending on the form of occurrence in the earth's crust, it can be dense or porous. Minerals are classified according to their structure:

clastic - conglomerate, gravel, sandstone, pelitic;
concretionary - legumes, oolitic.

The main minerals for ore formation are:

diaspora;
hydrogoethite;
goethite;
boehmite;
gibbsite;
kaolinite;
ilmenite;
aluminohematite;
calcite;
siderite;
mica.

There are bauxites of platform, geosynclinal and oceanic islands. Aluminum ore deposits were formed as a result of the transport of weathering products of rocks, followed by their deposition and the formation of sediment.

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

Deposits and extraction of raw materials

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

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

Bauxite is mined by open and underground methods. The technological process of processing raw materials depends on its chemical composition and involves stage-by-stage execution of work.

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

Several methods are used to form alumina:

sintering;
hydrochemical;
combined.

Application of mineral resource

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

Bauxite is used for the production of paints, abrasives, and sorbents. Ore with a low iron content is used in the manufacture of refractory compounds.

Aluminum is one of the most popular and sought-after metals. In every industry it is not added to the composition of certain items. From instrument making to aviation. The properties of this lightweight, flexible and corrosion-resistant metal have appealed to many industries.

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

Differences in saturation

Basically, there are only three types of ores worth mentioning 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, due to the very high concentration, the most profitable extraction will be from bauxite, alunite and nepheline.

Nephelines are an alkaline formation that appeared due to the high temperature of magma. One unit of this ore will yield up to 25% alumina 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 are obviously recognized as unprofitable.

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

And the first place, with a record aluminum oxide content of fifty percent or more, goes to bauxite! They are rightfully considered the main source of alumina. However, regarding their origin, scientists still cannot come to the only correct decision.

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

Aluminum mining methods

The necessary ores are mined in two ways.

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

Bauxite and nepheline, as higher density structures, are cut by milling using a surface miner. Of course, it all depends on the manufacturer and model of the machine, but, on average, it is capable of removing up to 60 centimeters of rock at a time. After a complete passage of one layer, a so-called shelf is created. This method ensures that the combine operator remains safe in his position. In the event of a collapse, both the chassis and the operator's cab will be safe.

The second group contains alunites, which, due to their friability, are mined by quarry excavators and then unloaded onto dump trucks.

A radically different method is to punch a shaft. Here the mining principle is the same as in coal mining. By the way, the deepest aluminum mine in Russia is the one located in the Urals. The depth of the mine is 1550m!

Processing the resulting ore

Next, regardless of the chosen extraction method, the resulting minerals are sent to processing workshops, where special crushing devices break the minerals into fractions approximately 110 millimeters in size.

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

Having gone through decomposition and received an aluminate pulp at the exit, we will send the pulp to be separated and drained from the liquid.

At the final stage, what is obtained is cleaned from alkalis and sent back to the oven. This time - for calcination. The finale of all actions will be the same dry alumina that is needed to obtain aluminum through hydrolysis.

Even though opening a shaft is considered a more difficult method, it is less harmful to the environment than the 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 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 the second list contains the world leaders in the direct extraction of aluminum ore.

So, in terms of natural (although not realized everywhere, yet) wealth, the situation is like this:

Guinea
Brazil
Jamaica
Australia
India

These countries can be said to possess the vast majority of Al 2 O 3 in the world. They account for 73 percent in total. The remaining reserves are scattered around the globe in less generous quantities. Guinea, located in Africa, is, in a global sense, the largest deposit of aluminum ores in the world. It “grabbed” 28%, which is even more than a quarter of the global deposits of this mineral.

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

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

You can also add to this list Jamaica, capable of producing 9.7 million tons, and Russia, with its figure of 6.6 million tons.

Aluminum in Russia

Regarding aluminum mining in Russia, only the Leningrad region and, of course, the Urals, as a true storehouse of mineral resources, can boast of certain indicators. The main method of extraction is mining. They mine four-fifths of all ore in the country. In total, on the territory of the Federation there are more than four dozen deposits of nepheline and bauxite, the resources 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 Cap deposit in the Sverdlovsk region) contain only half of alumina. Whereas Chinese or Italian rocks are saturated with Al 2 O 3 by sixty percent or more.

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

Application of aluminum

As we already stated 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. The ore itself, for example, contains small quantities of other metals, such as vanadium, titanium and chromium, useful for steel alloying processes. There is also a benefit at the alumina stage, because alumina is used in ferrous metallurgy as a flux.

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

So, only one thing is certain. For many more years, humanity's need for aluminum, as well as its compounds, will not fade away. Which, accordingly, speaks exclusively of an increase in its production volumes.

Industrial importance of aluminum

Types of aluminum ores

Bauxite ore

How is bauxite aluminum ore formed?

Alunite ores

Nepheline

World production of aluminum ores

Ore deposits in Russia

Industrial importance of aluminum

Types of aluminum ores

Bauxite ore

How is bauxite aluminum ore formed?

Alunite ores

Nepheline

World production of aluminum ores

Ore deposits in Russia

Characteristics of ore mineral

Gallery: bauxite stone (25 photos)

Bauxite (video)

Deposits and extraction of raw materials

Bauxite processing line (video)

Application of mineral resource

Aluminum mining

Aluminum ores of Russia

Aluminum production in Russia

Story

Receipt

Physical properties

Being in nature

Prevalence

Natural aluminum compounds

Isotopes of aluminum

Chemical properties

Production and market

Application

As a reducing agent

Aluminum alloys

Aluminum as an additive to other alloys

Jewelry

Cutlery

Glass making

Food industry

Military industry

Aluminum and its compounds in rocket technology

Aluminum energy

Aluminum in world culture

Toxicity

see also

Notes

Links

Characteristics of ore mineral

Deposits and extraction of raw materials

Application of mineral resource

Differences in saturation

Aluminum mining methods

Processing the resulting ore

Aluminum mining in the world

Aluminum in Russia

Application of aluminum