Where can you find aluminum in nature?

We often use aluminum foil in our household, cook in aluminum cookware, and drink carbonated drinks from aluminum cans. Many people have an idea about the physical and chemical properties of aluminum. It is no secret that this light silver metal is in demand today in various industries from food to space. At the same time, few people know how aluminum is mined in nature and how complex the production process is.

What mineral is aluminum mined from?

Aluminum is considered an active metal. Due to its high chemical activity, its atoms form compounds with other substances. In its pure form, this “winged metal”, under natural conditions, is practically never found on planet Earth. The main starting material used in the production of pure aluminum is alumina. This raw material is technical aluminum oxide Al203 – white crystalline powder. The source of the starting material is aluminum ore. In the earth’s crust it is about 9%.

Types and properties of aluminum ore

There are several types of aluminum ores in the world. Global aluminum producers most often use 3 types:

• Bauxite;
• Alunites;
• Nepheline syenites;

Bauxite contains alumina in the greatest quantity, compared to alunite and nepheline rocks (from 40% to 60%), and therefore is more in demand in aluminum production. This aluminum ore consists of aluminum oxide hydrates, iron oxides and silicon oxides. A rock is considered high quality if it contains more than 50% aluminum oxide. Bauxite can be hard or crumbly, dense or loose. Depending on the impurities they differ in color. Brick red, red and brown “speak” of the presence of iron oxide. Light (pink, gray-white) indicate a low content of iron oxide. From 4-5 tons of bauxite, 2 tons of alumina come out and, as a final result, 1 ton of aluminum. Bauxite ore is ground into powder, silicon additives are separated under the influence of steam and the finished raw material is obtained for smelting.

Over the 130-year history of the discovery of aluminum, scientists have not been able to understand the origin of aluminum ore, in particular bauxite. Either it is a residual product that was obtained after the dissolution of some limestones; either a sediment resulting from the decomposition of aluminum, iron and titanium salts, or bauxite formed under the influence of weathering, transport and deposition of ancient rocks.

Unlike bauxite, on which the entire global aluminum industry is based, alunite and nepheline are not so popular among producers of the “winged metal”.

Alunites have a porous structure, as they are formed under the influence of hydrothermal and volcanic activity. They contain up to 40% aluminum oxide compounds and various additives.

Nephelines are alkaline formations that arise due to the high temperature of magma. The ore is not of particular interest to miners, as it is recognized as the poorest in alumina content. Its development is not profitable, since only 25% of alumina comes out of one unit of crystalline samples.

Aluminum mining methods

Aluminum is a relatively young metal. The production method was developed in 1886, and industrial production began only at the beginning of the 20th century. Over the years, aluminum mining technology has improved. Modern geological exploration quickly identifies aluminum ore deposits, having an understanding of the origin and formation conditions that affect the structure and composition of the minerals. If the deposit is considered profitable, methods for extracting aluminum ore are determined.

When aluminum rocks are shallow, mining is carried out using open-pit mining. The choice of method depends on the type and structure of the minerals.

• Crystalline rocks (bauxite and nepheline) are cut using the milling method using a surface miner. Depending on the machine model, a 60 cm thick layer can be removed at a time. For the safety of the combine operator, the rock thickness is developed gradually, forming shelves after a complete passage of one layer.
• Loose rocks (alunites) are cut off by quarry excavators and immediately loaded into dump trucks for further transportation.

Aluminum mining in Russia is mainly carried out using closed methods in mines. This method produces 80% of the total mass of aluminum ore in our country.

Transportation and handling

Mining and processing plants that carry out primary processing of feedstock are usually built near the mining site. Belt conveyors are used to supply ore for processing. If the processing plant is located far from a natural deposit, raw materials are transported by dump trucks.

The next stage is preparing the rock for processing into alumina (aluminum oxide)

1. The ore is moved to the raw material preparation workshop using a conveyor belt, where special crushing devices break the minerals into fractions measuring 110 mm;
2. They supply ore and the necessary chemical additives for further processing to the second section of the preparatory workshop;
3. The rock is sintered in ovens.

At this stage, hydrometallurgical leaching treatment is possible. After the decomposition stage, aluminum pulp is obtained, which is evaporated from the liquid, cleaned of unnecessary alkalis and sent for calcination in a furnace. As a result of such a complex technological process, dry alumina is formed – a key raw material for the production of aluminum by electrolysis. Aluminum production requires large amounts of electricity. In this regard, the Russian aluminum industry has advantages. These are relatively low prices for electricity and the proximity of power plants to electrolysis production.

Aluminum production in the world by country

The main deposits of bauxite are concentrated in tropical and subtropical zones. 73% of the world’s ore reserves are found in 5 countries: Guinea, Brazil, Jamaica, Australia and India. The total world reserves of proven bauxite are more than 30 billion tons. 7,4 billion tons – in Guinea. This African country has the largest deposits of high-quality bauxite, with an alumina content of 50-60% and silica 1-3%. They lie almost on the surface, so development is carried out in an open way. 20% of global aluminum production using Guinean bauxite.

Leading countries in aluminum production

• China – 86,5 million tons;
• Australia – 81,7 million tons;
• Brazil – 30,7 million tons;
• Guinea – 19,7 million tons;
• India – 15 million tons.

The list of main aluminum ore miners also includes:

• Jamaica – 9,7 million tons;
• Russia – 6,6 million tons;
• Kazakhstan – 4,2 million tons;
• Guyana – 1,6 million tons.

Where is aluminum mined in Russia?

The development of aluminum ore deposits in the Russian Federation is carried out mainly using closed methods. The ore lies deep and mines have to be built to extract it. The deepest mine in the world, “Cheryomukhovskaya-Glubokaya” (1550 m), is located in the Urals.

• The main areas of aluminum (bauxite) mining are: Northern Ural region; Arkhangelsk, Sverdlovsk, Belgorod and Leningrad regions; Komi Republic (Sredne-Taman deposits);
• The world’s largest nepheline deposits are in the Kemerovo and Murmansk regions, Kuznetsk Alatau, Krasnodar Territory, on the Kola Peninsula and the Urals;
• Alunite reserves are concentrated in the Amur region, Transbaikalia and Primorsky Krai.

• Red Riding Hood (Ural) – according to experts, reserves will last for 19 years;
• Gornostayskoye and Gornostaysko-Krasnooktyabrskoye (Sverdlovsk region) – production volumes are predicted for 18 years;
• Blinovo-Kamenskoye and Kurgazakskoye – 10 years.

The leading positions in the development of deposits are occupied by the South Ural bauxite mines, JSC Sevuralboxitrude and Baksigorsky Alumina.

An alternative to aluminum ore mining in the Russian Federation

Despite the fact that Russia is one of the top countries in aluminum production, occupying 6-8th place in terms of the volume of extracted rock, it is necessary to import 3 million tons of alumina from other countries annually. Bauxite deposits in the Russian Federation are characterized by low quality raw materials. The alumina produced is not enough to meet the needs of the Russian aluminum industry. In addition, there is underdevelopment of the production of aluminum alloys and products from recycled materials. The situation in the domestic aluminum industry may improve significantly in the coming years.

• It is planned to reduce energy consumption and the environmental burden through the introduction of new technologies for the production of aluminum and products made from it.
• Changes are planned due to the annual processing of 600 thousand tons of aluminum scrap. Recycled metal is cheaper than primary aluminum, the production of which requires 20 thousand kW of energy per ton.
• Mining is carried out on the African continent. Today, RUSAL (the world’s largest producer of primary aluminum and alumina) produces 40% of bauxite in the Republic of Guinea. Owns the Kindia bauxite company (3,5 million tons per year), Dian-Dian (3 million tons per year) and the Friguia bauxite-alumina complex (2,1 million tons per year). The Dian-Dian mine alone has proven bauxite reserves of 564 million tons.

To summarize, it should be noted that the future of the Russian aluminum industry is very optimistic. In the next decade, ore mining and smelting volumes will only grow. The production of products from recycled aluminum and aluminum alloys will be established.

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    Aluminum – a chemical element, a light non-ferrous metal of silver color. It is located in group III in period III, serial number 13 in the periodic table of chemical elements of Dmitry Ivanovich Mendeleev. Aluminum is an amphoteric metal, a strong reducing agent, and interacts with simple and complex substances. Aluminum is easy to form, cast, and machine. It has high thermal and electrical conductivity, strength and good corrosion resistance. Due to its high chemical activity, aluminum occurs in nature only in the form of compounds. Aluminum is the most common metal on Earth. The surface of aluminum is covered with a durable oxide film, which protects aluminum from oxidation and gives it corrosion resistance. Devoid of an oxide film, aluminum reacts violently with water, releasing hydrogen. Lightweight aluminum with high thermal and electrical conductivity, combined with corrosion resistance, is widely used in technology and everyday life [1].

    Historical information

    

    The name “aluminum” comes from the Latin “alumen”. This is the name given to aluminum alum, which was used as a mordant for dyeing fabrics and tanning leather, 500 years BC. Aluminum was first obtained by Hans Christian Oersted in 1825 by the action of potassium amalgam on aluminum chloride followed by distillation of mercury. In 1854, Henri Etienne Sainte-Clair Deville obtained aluminum on an industrial scale by reducing sodium tetrahydroxyaluminate Na₃AlCl₆ metallic sodium. The modern electrolytic method for producing aluminum was developed in 1886 in France by Charles Martin Hall and Paul Louis Toussaint Héroux in the USA simultaneously and independently of each other [1].

    Structure of aluminum

    Periodic table of chemical elements by D. I. Mendeleev

    Aluminum is located in the main subgroup of the third group, in the third period of the periodic table of chemical elements of D.I. Mendeleev. Electronic structure of aluminum in the “ground” state 1s²2s²2p 6 3s²3p¹, in the “excited” state 1s²2s²2p 6 3s¹3p². Aluminum exhibits paramagnetic properties. Aluminum in air quickly forms strong oxide films that protect the surface from further interaction, and therefore is resistant to corrosion. The aluminum atom has three electrons in its outer electron layer. In chemical reactions it acts as a reducing agent. The characteristic oxidation state of aluminum is +3, the charge of the ion is 3+ [2].

    In terms of prevalence in nature, aluminum ranks first among metals and third among all chemical elements. Aluminum in a free state does not occur in nature due to its high chemical activity; it exists only in the form of compounds [3].

    Finding aluminum in nature

    Aluminum is the third most abundant metal in nature among all elements after oxygen and silicon. The content in the earth’s crust is about 8%. In nature, aluminum is found in the form of compounds of bauxite, red (rubies) and blue (sapphires) corundum, kaolinites, cryolites and feldspar.

    Characteristics of natural aluminum compounds are given in Table 1 [4].

    Table 1 – Characteristics of natural aluminum compounds

    Aluminum connection	Chemical formula	Materials
    Bauxite (aluminum hydrate), Fe impurities2O3, CaCO3, SiO2	Аl2O3 • H2O	Amorphous with not bright, low shine, opaque compound. The specific gravity, if there is a lot of silica in the composition, is about 1,2 g/cm³. The specific gravity, which contains more iron, is 2,8 g/cm³. Bauxite hardness ranges from 2 to 7 on the Mohs scale. Cleavage is absent. The structure can be either porous or dense. Density from 2,5 to 3,5 g/cm [5].
    Corundum	Аl2O3	The color can be colorless, yellow, pink, red, brown, blue, purple, green, gray, and in powder – white. Based on their transparency, crystals are classified into transparent, translucent and opaque. There is no cleavage. The fracture has an uneven, conchoidal edge. It has a diamond matte, pearlescent, glassy sheen. Hardness on the Mohs scale 9. Specific gravity from 3,9 to 4,1 g/cm³. In polished corundum crystals, the effect of asterism can sometimes be seen [6].
    Feldspar	K2O•Al2O3 • 6 SiO2	Color: white, gray, yellowish, cream, pale pink, sometimes transparent, colorless, red, bluish-green and dark gray. Glass shine. Hardness on the Mohs scale from 6 to 6,5. Density from 2,5 to 3,4 g/cm³. Cleavage is perfect in two directions, at a right angle or close to it [7].
    Cryolite	Na3AlF6	The color is white; if there are impurities in the composition, it can be smoky, gray, red-brown and black. Hardness on the Mohs scale is from 2 to 3. The shine depends on the degree of purity of the stone; it can be either glassy or greasy. Density from 2,95 to 3,01 g/cm³. The fracture has an uneven, conchoidal edge [8].
    Kaolinite	Аl2O3 • SiO2 • 2H2O	Depending on the impurities, the color is white or brownish. The shine is matte, pearlescent, dull. Hardness on the Mohs scale from 2 to 2,5. Specific gravity from 2,61 to 2 g/cm68 [3].
    Silicate rocks (clay, mica)	is part of	Clay has plasticity, binding ability, heat resistance, the ability to absorb water, and a melting point of more than 1800°C [10].

    Mica has thermal stability and resistance to high temperatures, high electrical and thermal conductivity, chemical inertness and resistance to acids, alkalis, has a laminated structure, and is transparent [11].

    Physical properties of aluminum

    Aluminum is an amphoteric metal of silver-white color, hard, light, durable, has high electrical and thermal conductivity, and a melting point of 660 °C. Natural aluminum consists of one isotope 27 ₁₃Al. Aluminum has high ductility and good corrosion resistance. Easily amenable to pressing, rolling, forging, stamping, drawing. Aluminum is highly polished, anodized, and has high reflectivity (reflects up to 90% of incident light radiation). It is not hardened by heat treatment. Aluminum is well suited to gas, argon arc, and resistance welding [4] [1].

    In air, aluminum is coated with a thin, durable layer of aluminum oxide Al.₂O₃, which protects the metal from further oxidation and corrosion. When aluminum is burned in the presence of oxygen, temperatures above 3000 °C are reached. Aluminum is capable of displacing metals from compounds, which is used to produce metals and their alloys by reducing metal oxides (aluminothermy) [1].

    Chemical properties of aluminum

    Aluminum is a highly active amphoteric metal and exhibits strong reducing properties.

    

    Interaction of aluminum with simple substances

    • When interacting with atmospheric oxygen, it forms a strong oxide film of Al₂O₃, protecting aluminum from further oxidation:
    • When interacting with halogens, the reaction occurs at room temperature with the addition of a drop of water, which acts as a catalyst, to produce aluminum iodide AlI₃:
    • In chemical reactions with bromine Br₂ aluminum reacts with the release of heat and light to form aluminum bromide AlBr₃:
    • With chlorine Cl₂ aluminum reacts when heated aluminum foil is added to a flask with chlorine gas to form aluminum chloride AlCl₃:
    • When aluminum and sulfur S interact when heated (ignited), an exothermic reaction occurs with the release of heat and light, aluminum sulfide Al is obtained₂S₃:
    • Aluminum reacts with nitrogen N₂ at a temperature of 800 °C with the formation of aluminum nitride AlN:
    • When interacting with carbon C at a temperature of 2000 °C, aluminum carbide Al is formed₄С₃:

    Interaction of aluminum with complex substances

    • Protective oxide film Al₂O₃ does not allow aluminum to react even with water, but when it is removed, aluminum forms hydroxide when interacting with water, which releases hydrogen H₂[12]:
    • Aluminum interacts with oxides of less active metals, which are to the right in the electrochemical series of metal voltages. When interacting with iron (III) oxide Fe₂O₃ at temperatures from 2500 to 3000 ° C, pure molten iron is formed [12]:

    This method of producing metals by reducing them from metal oxides is called aluminothermy [12].

    • Aluminum reacts with dilute acids and acids with pronounced weak oxidizing properties. When interacting with them, aluminum salts are formed and hydrogen H is released₂[12]:
    • When interacting with acids that are strong oxidizing agents (sulfuric acid H₂SO_{4(concentrated)} , nitric acid HNO_{3(concentrated)}), when heated, salt and water are formed, hydrogen sulfide (H₂S) and nitrogen oxides (NO, NO₂) accordingly [12]:
    • When heating aluminum with dilute nitric acid HNO₃ nitrogen oxide (I) N is formed₂O and ammonium nitrate NН₄DO NOT₃[12]:
    • Aluminum reacts with aqueous solutions of alkalis NaOH to form a complex salt of sodium tetrahydroxoaluminate Na2(OH)₄> and sodium aluminate NaAlO₂ accordingly [12]:
    • An aqueous solution of aluminum, cleared of the oxide film, reacts with water to form aluminum hydroxide Al(OH)₃ and release of hydrogen H₂[12]:

    Obtaining

    Aluminum forms a strong chemical bond with oxygen. For the industrial production of aluminum, the Hall-Heroult process is used. To lower the melting point, aluminum oxide is dissolved in molten cryolite Na₃AlF₆ at a temperature of 960 – 970 ° C, then subjected to electrolysis with carbon electrodes. Electrolysis of aluminum oxide solution Al₂O₃ in molten cryolite Na₃AlF₆ occurs at a temperature of 950°C. The electrolysis bath is made in the form of an iron box. The hearth and side walls are lined with plates of a mixture of carbon and graphite, which serve as the cathode. Burnt plates of carbon mass, the anode, are lowered into the bath from above. When passing a direct electric current, aluminum oxide Al₂O₃ decomposes into aluminum Al, which accumulates on the hearth, and oxygen O₂, forming carbon oxides CO and CO with the anode material₂. Molten aluminum, containing about 1% impurities, is poured into molds or cast by a continuous process. High-purity aluminum with an impurity content of no more than 0,05% of impurities is obtained from it by electrolytic refining. When producing aluminum by zone smelting, the content of nitrogen and sulfur should not exceed 10,4%, any other impurity – no more than 0,00001%. Aluminum production involves high energy consumption. As a result of the process, aluminum is released at the cathode, and oxygen is released at the anode [2] [4] [1]:

    Aluminum is produced from Al bauxite₂O₃ • H₂O by electrolysis at a temperature of 1000 °C. Since the melting point of aluminum oxide is 2500 °C, it is not possible to carry out electrolysis at this temperature, so aluminum oxide is dissolved in molten cryolite, and then the resulting electrolyte is used in electrolysis to produce aluminum [4].

    Application of aluminum

    

    

    

    Gas storage tank

    Aluminum is a common alloying additive in alloys based on copper, magnesium, titanium, zinc, nickel, and iron. The use of aluminum is given in Table 2 [1] [13].

    • in electrical engineering for the manufacture of cables and conductive products;
    • electronics for the manufacture of semiconductor devices;
    • for the manufacture of mirrors – reflectors;
    • for the production of special chemical equipment and tanks for storing and transporting liquid gases – methane, oxygen, hydrogen, ammonia, nitric and acetic acid, clean water, edible oils;
    • for manufacturing as a structural material for nuclear reactors;
    • for deoxidation in steel production;
    • in aluminothermy for the production of metals and their alloys;
    • powdered aluminum is used as a component of explosives and rocket fuels;
    • in the construction of buildings and objects as a structural material [1] ;
    • for the manufacture of parts for household electrical appliances, boilers, pots, dishes, furniture, sports equipment, cornices, boats, food containers;
    • Aluminum hydroxide is used in tanning leather and as a mordant when dyeing fabrics [1];

    Literature

    1. General chemistry. Textbook / ed. S. F. Dunaeva. – M.: Academia, 2017. – 160 p.
    2. General and inorganic chemistry: textbook / ed. V. V. Denisova, V. M. Talanova. — Rn/D: Phoenix, 2018. — 144 p.
    3. Glinka N. L. General chemistry: a textbook for secondary vocational education. – M.: KnoRus, 2019. – 360 p.
    4. Glinka N. L. General chemistry: textbook for universities / ed. A. I. Ermakova. – M.: Integral-Press, 2003. – 728 p.
    5. Karapetyants M. Kh. General and inorganic chemistry: textbook / M. Kh. Karapetyants, S. I. Drakin. – M.: KD Librocom, 2015. – 592 p.
    6. Karapetyants M. Kh. General and inorganic chemistry / ed. M. Kh. Karapetyants, S. I. Drakin. – M.: Lenand, 2018. – 600 p.

    Note

    1. ↑ 1,01,11,21,31,41,51,61,71,8Aluminum(undefined) . Great Russian Encyclopedia. Access date: November 8, 2023.
    2. ↑ 2,02,1 Aluminum. Chemistry of aluminum and its compounds(undefined) . Khimik.ru. Access date: November 7, 2023.
    3. ↑Structure and properties of aluminum and its compounds(undefined) . Foxford. Access date: November 7, 2023.
    4. ↑ 4,04,14,24,3 Aluminum (Al)(undefined) . Chemistry is easy. Access date: November 8, 2023.
    5. ↑Bauxite: definition, properties, deposits and application(undefined) . Scientific articles.Ru. Access date: November 7, 2023.
    6. ↑Corundum(undefined) . Crystals.net. Access date: November 7, 2023.
    7. ↑Feldspar(undefined) . Great Russian Encyclopedia. Access date: November 7, 2023.
    8. ↑Cryolite: properties and uses of stone(undefined) . Website about stones. Access date: November 7, 2023.
    9. ↑Kaolinite(undefined) . Crystals.net. Access date: November 7, 2023.
    10. ↑Clays: basic properties and application in construction and industry(undefined) . Scientific articles.Ru. Access date: November 8, 2023.
    11. ↑Mica: properties, applications and features of this unique material(undefined) . Scientific articles.Ru. Access date: November 8, 2023.
    12. ↑ 12,012,112,212,312,412,512,612,712,8Characteristic chemical properties of aluminum(undefined) . Science for you. Access date: November 8, 2023.
    13. ↑Application of aluminum and its compounds(undefined) . YaClass. Access date: November 9, 2023.