What are aluminum ores used for?

How is aluminum ore mined and where is it used?

Aluminum is a fairly young metal when compared with others that were in demand in ancient times. It was only in the second half of the 19th century that the metal began to be produced in large quantities; before that it was used infrequently.

The industrial scale of the “winged” metal began only in the 20th century. Today, it is one of the sought-after materials in various industries from electronics to the space and aviation industries.

Aluminum ore was first obtained in the form of a silvery metal in 1825 in a volume of just a few milligrams, and before the advent of mass production, this metal was more expensive than gold.

For example, one of the royal crowns of Sweden contained aluminum, and D. I. Mendeleev in 1889 received an expensive gift from the British - scales made of gold and aluminum.

What raw materials are needed to produce aluminum ore? How is one of the most essential materials of our time produced?

Bauxite ore is the basis of global aluminum production

The silver metal itself is directly obtained from alumina.

This raw material is aluminum oxide (Al2O3), obtained from ores:

• Bauxite;
• Alunitov;
• Nepheline syenites.

The most common source of starting material is bauxite, which is considered the main aluminum ore.

Despite the more than 130-year history of discovery, it has still not been possible to understand the origin of aluminum ore. It is possible that simply in each region the raw materials were formed under the influence of certain conditions. And this makes it difficult to derive one universal theory about the formation of bauxite.

There are three main hypotheses about the origin of aluminum raw materials:

1. They were formed due to the dissolution of certain types of limestone as a residual product.
2. Bauxite was obtained as a result of weathering of ancient rocks with their further transport and deposition.
3. The ore is the result of chemical processes of decomposition of iron, aluminum and titanium salts, and fell as sediment.

However, alunite and nepheline ores were formed under different conditions from bauxite. The former were formed under conditions of active hydrothermal and volcanic activity. The second - at high temperatures of magma.

As a result, alunites generally have a crumbly porous structure. They contain up to 40% of various aluminum oxide compounds. But, in addition to the aluminum-bearing ore itself, the deposits, as a rule, contain additives, which affects the profitability of their mining. It is considered profitable to develop a deposit with a 50 percent ratio of alunites to additives.

Nephelines are usually represented by crystalline samples, which, in addition to aluminum oxide, contain additives in the form of various impurities. Depending on the composition, this type of ore is classified into types. The richest contain up to 90% nephelines, second-rate 40-50%; if the minerals are poorer than these indicators, then it is not considered necessary to develop them.

Having an idea of ​​the origin of minerals, geological exploration can quite accurately determine the location of aluminum ore deposits. Also, the formation conditions, which influence the composition and structure of minerals, determine the extraction methods. If the deposit is considered profitable, its development is established.

Properties of aluminum ore

Bauxite is a complex compound of oxides of aluminum, iron and silicon (in the form of various quartz), titanium, as well as with a small admixture of sodium, zirconium, chromium, phosphorus and others.

The most important property in aluminum production is the “breakability” of bauxite. That is, how easy it will be to separate unnecessary silicon additives from it in order to obtain the feedstock for metal smelting.

The basis for producing aluminum is alumina. To form it, the ore is ground into a fine powder and heated with steam, separating most of the silicon. And this mass will become the raw material for smelting.

To obtain 1 ton of aluminum, you will need about 4-5 tons of bauxite, from which, after processing, about 2 tons of alumina are formed, and only then you can get the metal.

Technology for the development of aluminum deposits. Aluminum ore mining methods

When the depth of occurrence of aluminum-bearing rocks is insignificant, they are mined using open-pit mining. But the process of cutting off ore layers will depend on its type and structure.

• Crystalline minerals (usually bauxite or nepheline) are removed by milling. Mineral miners are used for this purpose. Depending on the model, such a machine can cut a layer up to 600 mm thick. The rock thickness is developed gradually, forming shelves after passing through one layer.

This is done to ensure the safe position of the operator’s cabin and running gear, which in the event of an unexpected collapse will be at a safe distance.

• Loose aluminum-bearing rocks preclude the use of milling. Since their viscosity clogs the cutting part of the machine. Most often, these types of rocks can be cut using mining excavators, which immediately load the ore onto dump trucks for further transportation.

Transporting raw materials is a separate part of the entire process.
Usually, whenever possible, enrichment plants try to be built near mining sites. This allows the use of belt conveyors to supply ore for processing. But, more often, confiscated raw materials are transported by dump trucks. The next stage is the enrichment and preparation of rock to obtain alumina.

• The ore is moved using a belt conveyor to the raw material preparation workshop, where a number of crushing devices can be used, crushing the minerals one by one to a fraction of approximately 110 mm.
• The second section of the preparatory workshop supplies prepared ore and additional additives for further processing.
• The next stage of preparation is sintering the rock in furnaces.

Also at this stage, it is possible to process raw materials by leaching with strong alkalis. The result is a liquid aluminate solution (hydrometallurgical processing).

• The aluminate solution goes through a decomposition stage. At this stage, an aluminate pulp is obtained, which in turn is sent for separation and evaporation of the liquid component.
• After which this mass is cleaned of unnecessary alkalis and sent for calcination in ovens. As a result of this chain, dry alumina is formed, which is necessary for the production of aluminum by hydrolysis treatment.

The complex technological process requires large amounts of fuel and limestone, as well as electricity. This is the main factor in the location of aluminum smelters - near a good transport interchange, and the presence of nearby deposits of the necessary resources.

However, there is also a mining method of extraction, when rock is cut out from the layers according to the principle of coal mining. After which the ore is sent to similar plants for enrichment and aluminum extraction.

One of the deepest “aluminum” adits is located in the Urals in Russia, its depth reaches 1550 meters!

Leading countries in aluminum ore production

The main deposits of aluminum are concentrated in regions with a tropical climate, and most of the 73% of deposits are found in just 5 countries: Guinea, Brazil, Jamaica, Australia and India. Of these, Guinea has the richest reserves, more than 5 billion tons (28% of the world share).

If we divide reserves and production volumes, we can get the following picture:

• 1st place – Africa (Guinea).
• 2nd place - America.
• 3rd place – Asia.
• 4th place – Australia.
• 5th – Europe.

The top five countries in aluminum ore production are presented in the table

A country	Production volumes million tons
China	86,5
Australia	81,7
Brazil	30,7
Guinea	19,7
India	14,9

Also, the main producers of aluminum ores include: Jamaica (9.7 million tons), Russia (6.6), Kazakhstan (4.2), Guyana (1.6).

Development of aluminum ore deposits in Russia

In our country there are several rich deposits of aluminum ores, concentrated in the Urals and in the Leningrad region. But the main method of extracting bauxite in our country is the more labor-intensive closed mine method, which extracts about 80% of the total mass of ores in Russia.

The leaders in deposit development are the joint-stock company Sevuralboxitrude, JSC Baksitogorsk Alumina, and the South Ural Bauxite Mines. However, their reserves are running out. As a result, Russia has to import about 3 million tons of alumina per year.

Field	Reserves
Little Red Riding Hood (Ural)	For 19 years of production
Gornostayskoye and Gornostaysko-Krasnooktyabrskoye	For 18 years of production
Blinovo-Kamenskoye	10 years
Kurgazskoe	10 years
Radynsky quarry	7 years

In total, 44 deposits of various aluminum ores (bauxite, nepheline) have been explored in the country, which, according to estimates, should be enough for 240 years, with such mining intensity as today.

The import of alumina is due to the low quality of the ore in the deposits, for example, bauxite with a 50% alumina composition is mined at the Red Cap deposit, while in Italy rock with 64% aluminum oxide is extracted, and in China 61%.

Applications of Aluminum Ore

Basically, up to 60% of ore raw materials are used to produce aluminum. However, the rich composition makes it possible to extract from it other chemical elements: titanium, chromium, vanadium and other non-ferrous metals, which are necessary primarily as alloying additives to improve the quality of steel.

As mentioned above, the technological chain for producing aluminum necessarily passes through the stage of formation of alumina, which is also used as fluxes in ferrous metallurgy.

The rich composition of elements in aluminum ore is also used to produce mineral paint. Also, the smelting method produces alumina cement - a quickly hardening, strong mass.

Another material obtained from bauxite is electrocorundum. It is obtained by smelting ore in electric furnaces. It is a very hard substance, second only to diamond, making it popular as an abrasive.

Also, in the process of obtaining pure metal, waste is formed - red mud. The element scandium is extracted from it, which is used in the production of aluminum-scandium alloys, which are in demand in the automotive industry, rocket science, production of electric drives, and sports equipment.

Alternative to aluminum ores

The development of modern production requires increasingly large volumes of aluminum. However, it is not always profitable to develop deposits or import alumina from abroad. Therefore, metal smelting using recycled materials is increasingly being used.

For example, countries such as the USA, Japan, Germany, France, and the UK mainly produce secondary aluminum, amounting to up to 80% of global smelting.

Secondary metal is much cheaper compared to primary metal, the production of which requires 20,000 kW of energy/1 ton.

Source: https://vseprokamni.ru/metal/ruda-alyuminiya.html

Aluminum ore: deposits, mining

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 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.

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 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:

1. Monohydrate bauxite – contains alumina in monohydrate form.
2. Trihydrate - such minerals consist of alumina in trihydrate form.
3. 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. 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.

Several decades later, in terms of quantitative indicators of the aluminum industry, the countries of Eastern Europe, Latin America and the Soviet Union became the leaders. 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.

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.

Source: https://autogear.ru/article/177/023/alyuminievaya-ruda-mestorojdeniya-dobyicha/

Aluminum

Aluminum is a ductile and lightweight white metal coated with a silver matte oxide film. In the periodic system of D.I. Mendeleev, this chemical element is designated as Al (Aluminium) and is located in the main subgroup of group III, third period, under atomic number 13. You can buy aluminum on our website.

History of discovery

In the 16th century, the famous Paracelsus took the first step towards aluminum mining. From alum, he isolated “alum earth,” which contained the oxide of a then unknown metal. In the 18th century, the German chemist Andreas Marggraff returned to this experiment. He named the aluminum oxide “alumina,” which means “astringent” in Latin. At that time, the metal was not popular because it was not found in its pure form.

For many years, English, Danish and German scientists tried to isolate pure aluminum. In 1855, at the Paris World Exhibition, the metal aluminum created a sensation. Only luxury items and jewelry were made from it, since the metal was quite expensive. At the end of the 19th century, a more modern and cheaper method of producing aluminum appeared. In 1911, the first batch of duralumin, named after the city, was produced in Duren.

In 1919, the first airplane was created from this material.

Physical properties

Aluminum metal is characterized by high electrical conductivity, thermal conductivity, resistance to corrosion and frost, and ductility. It lends itself well to stamping, forging, drawing, and rolling. Aluminum can be welded well with various types of welding.

An important property is its low density of about 2.7 g/cm³.
The melting point is about 660°C. The mechanical, physicochemical and technological properties of aluminum depend on the presence and amount of impurities that worsen the properties of the pure metal.

The main natural impurities are silicon, iron, zinc, titanium and copper.

According to the degree of purification, aluminum is distinguished between high and technical purity. The practical difference is the difference in corrosion resistance to certain environments. The purer the metal, the more expensive it is. Technical aluminum is used for the production of alloys, rolled products and cable and wire products.

High purity metal is used for special purposes.
In terms of electrical conductivity, aluminum is second only to gold, silver and copper. And the combination of low density and high electrical conductivity allows it to compete with copper in the field of cable and wire products.

Long-term annealing improves electrical conductivity, while cold hardening worsens it.

The thermal conductivity of aluminum increases with increasing purity of the metal. Impurities of manganese, magnesium and copper reduce this property. In terms of thermal conductivity, aluminum is inferior only to copper and silver.

Due to this property, the metal is used in heat exchangers and cooling radiators.
Aluminum has a high specific heat capacity and heat of fusion. These figures are significantly higher than those of most metals.

The higher the purity of aluminum, the more it is able to reflect light from the surface. The metal is well polished and anodized.

Aluminum has a high affinity for oxygen and is covered in air with a thin, durable film of aluminum oxide. This film protects the metal from subsequent oxidation and provides its good anti-corrosion properties. Aluminum is resistant to atmospheric corrosion, sea and fresh water, and practically does not interact with organic acids, concentrated or diluted nitric acid.

Chemical properties

Aluminum is a fairly active amphoteric metal. Under normal conditions, a strong oxide film determines its durability. If the oxide film is destroyed, aluminum acts as an active reducing metal.

In a finely crushed state and at high temperatures, the metal interacts with oxygen. When heated, reactions occur with sulfur, phosphorus, nitrogen, carbon, and iodine. Under normal conditions, the metal reacts with chlorine and bromine. There is no reaction with hydrogen.

With metals, aluminum forms alloys containing intermetallic compounds - aluminides.

Provided that the oxide film is removed, vigorous interaction with water occurs. Reactions with dilute acids occur easily. Reactions with concentrated nitric and sulfuric acid occur when heated. Aluminum reacts easily with alkalis. Practical application in metallurgy has found the property of reducing metals from oxides and salts - aluminothermy reactions.

Receipt

Aluminum is in first place among metals and in third place among all elements in terms of abundance in the earth's crust. Approximately 8% of the mass of the earth's crust is this metal. Aluminum is found in the tissues of animals and plants as a trace element. In nature, it is found bound in the form of rocks and minerals. The rocky shell of the earth, which is at the base of the continents, is formed precisely by aluminosilicates and silicates.

Aluminosilicates are minerals formed as a result of volcanic processes under appropriate high temperature conditions.

During the destruction of aluminosilicates of primary origin (feldspars), various secondary rocks with a higher aluminum content (alunites, kaolins, bauxites, nephelines) were formed. Aluminum is included in secondary rocks in the form of hydroxides or hydrosilicates.

However, not every aluminum-containing rock can be a raw material for alumina, a product from which aluminum is produced using the electrolysis method.

Aluminum is most often obtained from bauxite. Deposits of this mineral are common in countries of the tropical and subtropical zone. In Russia, nepheline ores are also used, deposits of which are located in the Kemerovo region and on the Kola Peninsula. When extracting aluminum from nephelines, potash, soda ash, cement and fertilizers are also produced along the way.

Bauxite contains 40-60% alumina. It also contains iron oxide, titanium dioxide, and silica. The Bayer process is used to isolate pure alumina. In an autoclave, the ore is heated with caustic soda, cooled, and the “red mud” (solid sediment) is separated from the liquid. Afterwards, aluminum hydroxide is precipitated from the resulting solution and calcined to obtain pure alumina. Alumina must meet high standards for purity and particle size.

Alumina (aluminum oxide) is extracted from the mined and enriched ore. The alumina is then converted into aluminum using electrolysis. The final stage is recovery by the Hall-Heroux process. The process is as follows: during the electrolysis of an alumina solution in molten cryolite, aluminum is released.

The cathode is the bottom of the electrolysis bath, and the anode is carbon bars located in cryolite. Molten aluminum is deposited under a solution of cryolite with 3-5% alumina. The process temperature rises to 950°C, which is much higher than the melting point of aluminum itself (660°C).

Deep purification of aluminum is carried out by zone melting or distillation through subfluoride.

Application

Aluminum is used in metallurgy as a base for alloys (duralumin, silumin) and an alloying element (alloys based on copper, iron, magnesium, nickel).

Aluminum alloys are used in everyday life, in architecture and construction, in shipbuilding and automotive industry, as well as in space and aviation technology. Aluminum is used in the production of explosives.

Anodized aluminum (coated with colored films of aluminum oxide) is used to make jewelry. Metal is also used in electrical engineering.

Let's look at how various aluminum products are used

Aluminum tape is a thin aluminum strip 0.3-2 mm thick, 50-1250 mm wide, which is supplied in rolls. The tape is used in the food, light, and refrigeration industries for the manufacture of cooling elements and radiators.

Round aluminum wire is used for the manufacture of cables and wires for electrical purposes, and rectangular for winding wires.

Aluminum pipes are durable and resistant in rural and urban industrial areas. They are used in finishing works, road construction, construction of cars, aircraft and ships, production of radiators, pipelines and gas tanks, installation of heating systems, main pipelines, gas pipelines, water pipelines.

Aluminum bushings are characterized by ease of processing, installation and operation. They are used for the end connection of metal cables.

An aluminum circle is a solid round section profile. This product is used for the manufacture of various designs.

Aluminum rod is used to make nuts, bolts, shafts, fasteners and spindles.
About 3 mg of aluminum enters the human body through food every day. The most metal is found in oatmeal, peas, wheat, and rice. Scientists have found that it promotes regeneration processes, stimulates the development and growth of tissues, and affects the activity of the digestive glands and enzymes.

Aluminum sheet

Aluminum plate

Aluminum ingots

Aluminum corners

Aluminum wire

When using aluminum cookware at home, you must remember that only neutral liquids can be stored and heated in it. If, for example, sour cabbage soup is cooked in such a container, then aluminum will enter the food and it will have an unpleasant “metallic” taste.

Aluminum is included in medications used for diseases of the kidneys and gastrointestinal tract.

Source: https://cu-prum.ru/alyuminij1.html

How aluminum is mined and produced in industrial conditions

Aluminum is one of the most common metals in the earth's crust. This metal is the lightest and also has good thermal conductivity. It lends itself well to machining by casting, bends well, and is recyclable. Its main physical properties:

• It has a silvery color (with a hint of white);
• Easy;
• Density is about 2713 kg per square meter;
• Boiling point from 2518.9 degrees Celsius;
• High ductility up to 50%.

Aluminum production

Alumina deposits are present in almost all countries of the world. The initial stage of mining is Bauxite ore. This name is derived from the locality of Baux, located in the south of France. The top five countries in the sale and production of bauxite rock are the following countries:

• Russia up to 4.5 million tons per year;
• China up to 13.50 million tons per year;
• USA up to 2.5 million tons per year;
• Canada up to 3.5 million tons per year;
• Australia up to 2.0 million tons per year.

In addition, this included:

• Iceland up to 0.50 million tons per year;
• Tajikistan up to 0.43 million tons per year;
• UAE up to 0.90 million tons per year;
• Germany up to 0.56 million tons per year;
• Brazil up to 1.70 million tons per year;
• India up to 1.30 million tons per year.

Metal ore is divided according to quality, and the content of foreign impurities affects the criteria for demand in the sales market:

• An increased amount of sulfur complicates the process of processing the substance into a pure alloy;
• High silicon module content improves product quality;
• The presence of carbonates in the ore complicates the process of processing the rock;
• The lowest iron content makes it easier to extract metal from underground.

Raw materials for production

The following categories of chemical elements are included in the production of aluminum:

Nephelines . They consist of nepheline syenites and urtites. The main components of the latter are apatite and nepheline. The components are processed and an apatite nepheline concentrate is obtained.

Alunite . It is a basic aluminum and sodium sulfate. It is a complex raw material consisting of sulfuric anhydride and alkali.

Cryolite . The connection is created artificially. Fluorspar is diluted with sulfuric acid in special self-stirring furnaces. The resulting volatile fluorosilicic acid is filtered using water towers installed above the baths. Afterwards, the industrial solution is cleaned with soda.

The next stage is aimed at obtaining cryolite. Hydrofluoric acid is diluted with aluminum hydroxide and soda, immersed in large boilers, where metal ore is smelted. The cryolite settles, then it is filtered and dried at a temperature of 150 degrees Celsius.

Bauxite alloy consists of oxides of iron, silicon and aluminum hydroxides. This raw material is used as a flux in smelting metallurgy.

The mined soil looks like clay. Has a homogeneous structure. A pisiform striped pattern is often encountered. The tropical climate contributes to the formation of high-quality ore composition. Under high temperatures, minerals in the earth's crust decompose, forming the final product Bauxite. Next, the resulting composition is purified from gas impurities.

Aluminum alloy has a strong bond with oxygen, so the process of extracting it from the soil is more difficult than other metals. To obtain the desired compound, alumina is processed in stages:

1. Metal ore deposits are mined;
2. Alumina or aluminum oxide is obtained from the deposits;
3. Next, the chemical element is split in a molten electrolyte.

The final point of the recycling process was named Hall-Heroult in 1886. The main developers of the modern melting method were Charles Hall and Paul Heroux.

To produce one ton of silver compound, 2000 kg are required. alumina, 40 kg. fluoride, 70 kg. cryolite and about 600 kg. graphite electrodes.

Necessary equipment

The foundry for aluminum processing uses technological developments:

• Electrolysis bath (electrolysis method);
• Vessel for refining.

Electrolyzers come in different sizes. Containers are produced with a self-burning anode and an upper current conductor or with an already baked anode.

A bath with baked anodes is more powerful and productive. It emits less harmful substances than its predecessor. It is a rectangular device in shape with a bottom inside up to 0.5 meters deep. The electric power of the bath depends on the current supplied to it. The current strength ranges from 30 kA to 250 kA. The surface of the walls is covered with a steel casing. Inside there is an additional layer of fireclay, on top of which coal slabs are laid. The bottom is also formed by coal blocks.

The refining container resembles an electrolyte container. Consists of a coal hearth. The vessel has heat-insulating linings and live wires. The heating temperature reaches up to +1000 degrees Celsius.

In addition to electrolytes, cooling furnaces and vessels for evaporating liquids are used. On our website there is a detailed video on the production of metal ore.

One of the world's novelties is metal mining using an electrochemical inert anode. This technology does not emit carbon dioxide into the atmosphere, but rather releases pure oxygen. One tank can produce more than 8,000 tons of oxygen per year. Currently, the industry is launching new equipment.

Aluminum production technologies

The metal is obtained by extracting alumina from bauxite ores. It is produced by three methods:

• Acidic dissolution of aluminum;
• Alkaline dissolution of aluminum;
• Electrolytic method.

Frequently used methods for obtaining metal are alkaline dissolution of aluminum ore and electrolytic production of aluminum. The alkali quickly dissolves the aluminum chemical solution. The mixture is diluted with aluminum hydroxypod. Manufacturing occurs in stages:

• The alumina composition is crushed with the addition of alkali or lime to a homogeneous consistency;
• The crushed pulp is placed in an autoclave at a temperature of +240 degrees Celsius and leached at high temperatures;
• In a solution of sodium aluminate and sodium silicate, the insoluble element sodium aluminosilicate is formed. The waste solution is filtered by adding a dilute alkali mixture at a temperature of +140 degrees Celsius;
• The metal solution is pumped into decomposers (baths with a stirring device) with the addition of hydroxide. There, aluminum hydroxide is extracted at a low temperature (+80 degrees Celsius);
• The resulting mixture is sent for calcination. The oven temperature reaches +1300 degrees Celsius; when the oven rotates, the consistency completely evaporates the moisture.

Electrolysis process

Electrolytic reduction occurs by placing alumina metal rock into electrolysis every half hour. There, raw materials are fired at a temperature of about 1000 degrees Celsius. Industrial scale allows the use of baths with baked anodes for metal ore:

• The raw material is immersed in a vessel where the reaction of alumel ore occurs;
• Aluminum oxide produces aluminum chloride;
• The chlorine compound is filtered;
• The metal settles on the cathode.

Baths without the use of liquid cryolite save up to 35% energy, and also reduce the cost of expensive electrochemical cryolite.

Metal refining

Aluminum rock is immersed in a refining bath, after which it is divided into three components:

• Molten alumina (bottom layer);
• An electrolyte consisting of a mixture of barium chloride, fluorides or sodium;
• Metal film (top layer).

The composition of the anode is: nickel, manganese, lead or tin. A slight presence of magnesium is allowed, which is eliminated by chlorine flux. The end result is 99.9% aluminum.

The metal element is used to create vehicles, construct buildings or structures, as well as construct electronic devices or electrical wiring. The metal retains its original qualities, which allows the composition to be reused in production.

New technologies for smelting metal alloys are being developed that make it possible to economically consume electricity, as well as the world's ore reserves.

Source: https://oxmetall.ru/metalli/alyuminij/kak-proizvoditsya-alyuminij

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.

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:

1. Monohydrate bauxite – contains alumina in monohydrate form.
2. Trihydrate - such minerals consist of alumina in trihydrate form.
3. 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.

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.

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.

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.

Source: https://monateka.com/article/8689/

Properties of aluminum

The simple substance aluminum is a light, paramagnetic metal of silvery-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.

The main properties of aluminum include the following:

• Melting point 660.24 C;
• Boiling point 2500 C;
• Density:
  • solid Al (20 C) – 2.6996 g/cm3;
  • liquid Al (1000 C) – 2.298 g/cm3;
• Resistivity (20 C): – 23 · 10 – 6K – 1;
• Electrochemical equivalent: K = 3 · 0.3354 g/Ah;
• Standard electronic potential Fio = – 1.67 V.
• Aluminum is amphoteric:
  • forms salts with acids: 2Al + 6HCl = 2AlCl3 + 3H2
  • with alkalis - aluminum acid salts (aluminates) 2Al + 2NaOH + 6H2O = 2NaAl(OH)4 + 3H2.

Aluminum is a light metal element, one of the most common elements in the earth's crust - it ranks 3rd in abundance after oxygen and silicon, and 2nd in production and consumption after iron. Clark aluminum makes up 8.45% wt.

Aluminum resources are enormous, but the compounds are very stable, so isolating it in the form of pure metal requires large amounts of energy.

Aluminum ores

Aluminum is contained in ores in the form of the following minerals:

— α-Al2O3 – corundum (Known as a precious stone: ruby, sapphire. Second in hardness after diamond.) (Figure 2);

— Al(OH)3 = Al2O3 · 3H2O– gibbsite (Figure 3), hydrargylite;

— AlOOH = Al2O3 · H2O–belite, diaspore (Figure 4);

— Aluminosilicates: Al2O3 · SiO2 – kyanite (Figure 5), andalusite, sillimanite (the main components of urtite and synnyrite ores);

— (Na,K)2O · Al2O3 · 2SiO2 – nifeline (Figure 6);

— Al2O3 · 2SiO2 · 2H3O– kaolinite (Basis of kaolinite clays used in the production of dishes and paints) (Figure 7);

— Na3AlF6 = 3NaF · AlF3 – cryolite (ice stone is the only compound in which alumina dissolves) (Figure 8).

Figure 2-7 – Corundum, Gibbsite, Diaspore, Kyanite, Nipheline, Colinite, Cryolite

The first three minerals are the rock-forming minerals of bauxite ores. 95% of all alumina is obtained from bauxite raw materials [1].

Source: https://MetalSpace.ru/education-career/osnovy-metallurgii/metallurgiya-alyuminiya/678-svojstva-alyuminiya.html