BRIEF HISTORICAL INFORMATION. About 1900 years ago, Pliny the Elder first named alum, which was used as a mordant for dyeing fabrics, “alumene.” 1500 years later, the Swiss naturalist Paracelsus discovered that alum contains aluminum oxide. Pure aluminum was first extracted from bauxite by the Danish scientist G. Ørsted in 1825. In 1865, the Russian chemist N. Beketov obtained aluminum by displacing it with magnesium from molten cryolite (Na 3 AlF 6). This method found industrial application in Germany and France at the end of the 19th century. In the middle of the 19th century. aluminum was considered a rare and even precious metal. Currently, aluminum is second only to iron in terms of global production.

GEOCHEMISTRY. Aluminum is one of the elements most abundant in the earth's crust. Its clarke is 8.05%. Under natural conditions, it is represented by only one isotope, 27 Al.

Under endogenous conditions, aluminum is concentrated predominantly in alkaline nepheline- and leucite-containing rocks, as well as in some varieties of basic rocks (anorthosites, etc.). Significant masses of aluminum accumulate due to alunitization processes associated with hydrothermal processing of acidic volcanic formations. The largest accumulations of aluminum are observed in residual and redeposited weathering crusts of acidic, alkaline and basic rocks.

In the sedimentary process, alumina dissolves and is transported only in acidic (pH< 4) или сильно щелочных (pH >9.5) solutions. Precipitation of aluminum hydroxides begins at pH = 4.1. In the presence of SiO 2, the solubility of Al 2 O 3 increases, and in the presence of CO 2 it decreases. Colloidal Al 2 O 3 compared to colloidal SiO 2 is less stable and coagulates faster. Therefore, in the process of their joint migration, the separation of these elements occurs. Due to the different geochemical mobility of aluminum, iron and manganese compounds, their differentiation occurs in the coastal zone of sedimentation basins. Bauxite accumulates closer to the shore, in the upper part of the shelf - iron ores, and at the bottom of the shelf - manganese ores. Aluminum hydroxides have significant adsorption capacity. The minerals that make up bauxites constantly contain Fe, V, Cr, Zn, Mn, Cu, Sn, Ti, B, Mg, Zr, P, etc. in variable quantities.

MINERALOGY. Aluminum is a component of about 250 minerals. However, only a few of them are of industrial importance: diaspore and boehmite, gibbsite (hydrargillite), nepheline, leucite, alunite, andalusite, kyanite, sillimanite, etc.

Diaspora HAlO 2 (Al 2 O 3 content 85%) crystallizes in the orthorhombic system, the habit of the crystals is lamellar, tabular, needle-shaped, the aggregates are leafy, cryptocrystalline, stalactite-like. The color of the mineral is white, grayish, with an admixture of Mn or Fe - gray, pink, brown, glassy to diamond luster, hardness 6.5–7, specific gravity 3.36 g/cm 3 .

Boehmit AlOOH – polymorphic modification of diaspore (by the surname Boehm), lamellar crystals, cryptocrystalline aggregates, bean-shaped, white color, hardness 3.5–4, specific gravity ~ 3 g/cm 3 . Formed during hydrothermal alteration of nepheline.

Gibbsite (hydrargillite) Al(OH) 3 (Al 2 O 3 64.7%) crystallizes in a monoclinal, less often in a triclinic system, pseudohexagonal crystals, lamellar and columnar, porcelain-like aggregates, earthy, sintered, worm-shaped, spheroidal nodules, hardness 2.5–3, specific gravity 2.4 g/cm3.

Nepheline Na (Al 2 O 3 34%) crystallizes in the hexagonal system, the crystals are prismatic, short-columnar, thick-tabular, colorless, gray, meat-red, luster from glassy to greasy, hardness 5.5–6, specific gravity 2.6 g/cm 3.

Leucite K (Al 2 O 3 23.5%) – framework silicate, isostructural with analcime; crystals - tetragontrioctahedrons, dodecahedrons. The color of the mineral is white, gray, hardness 5.5–6, specific gravity 2.5 g/cm 3 .

Alunite KAl 3 (OH) 6 2 (Al 2 O 3 37%) crystallizes in the trigonal system, the crystals are tabular, rhombohedral or lenticular, the aggregates are dense and granular. The color of the mineral is white, grayish, yellowish, brown, glassy to pearlescent luster, hardness 3.5–4, specific gravity 2.9 g/cm 3 . It is found in the weathering crust, where H 2 SO 4 is abundant.

Andalusite Al 2 O (in the province of Andalusia, Spain) is one of three polymorphic modifications of aluminum silicate (andalusite, kyanite and sillimanite), formed at the lowest pressure and temperature. Aluminum is slightly replaced by Fe and Mn. Crystallizes in the rhombic system, the crystals are columnar, fibrous, granular and radiant-columnar aggregates, pink color, glassy luster, hardness 6.5–7, specific gravity 3.1 g/cm 3 .

The most important ores of aluminum are bauxite - a rock consisting of aluminum hydroxides, oxides and hydroxides of iron and manganese, quartz, opal, aluminosilicates, etc. mineral composition There are diaspore, boehmite, gibbsite, and complex bauxites, consisting of two or three of the listed minerals. Amorphous alumina, which is part of industrial aluminum minerals, ages over time, as a result of which it is transformed into boehmite, and the latter turns into gibbsite.

INDUSTRIAL APPLICATION. Aluminum, due to its lightness (density 2.7 g/cm3), high electrical conductivity, high corrosion resistance and sufficient mechanical strength (especially in alloys with Cu, Mg, Si, Mn, Ni, Zn, etc.), has found wide use in various industries. The main areas of application of aluminum and its alloys are: automobile, ship, aircraft and mechanical engineering; construction (load-bearing structures); production of packaging materials (containers, foil); electrical engineering (wires, cable); production of household items; defense industry.

RESOURCES AND RESERVES. The main raw material of the global aluminum industry is bauxite. Bauxite proper includes aluminous rocks containing at least 28% Al 2 O 3. Aluminum is also obtained from nepheline and alunite ores. An electrical engineering method has been developed for producing aluminum from sillimanite, andalusite, kyanite crystalline schists and gneisses and other non-bauxite alumina sources. Bauxites, as a rule, form areal deposits that reach the surface or are only slightly covered, as a result of which their discovery and establishment of the industrial characteristics of deposits is a relatively simple task.

World bauxite resources are estimated at 55–75 billion tons. About 33% of them are concentrated in South and Central America, 27% in Africa, 17% in Asia, 13% in Australia and Oceania, and only 10% in Europe and Northern Europe. America.

The total reserves of bauxite in the world are 62.2 billion tons, and proven reserves are 31.4 billion tons. The top six countries with the largest reserves are Guinea, Australia, Brazil, Jamaica, India and Indonesia (Table 8). These countries are the main suppliers of gibbsite bauxite to the world market. Other bauxite-mining countries, such as China and Greece, use boehmite-diaspore bauxite. Russia does not have sufficient reserves of bauxite for domestic consumption, and its share in the world balance of this raw material is less than 1%.

Unique deposits include deposits with bauxite reserves of more than 500 million tons, large – 500–50 million tons, medium – 50–15 million tons and small – less than 15 million tons.

MINING AND PRODUCTION. World bauxite production 1995–2000 amounted to 110–120 million tons. The main producers of bauxite were Australia, Guinea, Jamaica, Brazil and China. The volume of production of this type of mineral raw material in Russia was about 4–5 million tons, while in Australia it was 43 million tons. In Australia, the largest mining company is « Alcan Aluminum».

In Russia, the development and extraction of bauxite is carried out at the deposits of the Urals OJSC "Sevuralboxytruda" (SUBR) and OJSC "South Ural Bauxite Mines" (YBR), where proven reserves can ensure the operation of mines for 25–40 years. Bauxite is mined using the mining method from great depths.

Alumina production in the world from various mineral sources in 1995–2000. amounted to 43–45 million tons. In Australia, which is the undoubted world leader, the main producers of alumina are companies « Alcoa» , « Reynolds Metals» And « Comalco» .

METALLOGENY AND AGES OF ORE FORMATION. The most favorable conditions for the formation of bauxite deposits arose at the early stage of the geosynclinal stage, when geosynclinal deposits of alumina mineral raw materials were formed, as well as at the platform stage, when laterite and sedimentary deposits appeared.

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

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, and less commonly clay-like, rock that is uniform or layered in texture. Depending on the form of occurrence in 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. Place of Birth aluminum ore formed as a result of the transfer of weathering products rocks with their subsequent deposition and sediment formation.

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.

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.

World reserves of bauxite are concentrated in 18 countries located in 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 is the world leader in mining raw materials. Brazil has 6 billion tons of reserves, Vietnam has 3 billion tons, India's bauxite reserves differ high quality, amount to 2.5 billion tons, Indonesia - 2 billion tons. The bulk of the ore is concentrated in the 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 provides for 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 complicated 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.

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.

Compared to traditional metals (steel, copper, bronze), aluminum is a young metal. Modern way Its production was only developed in 1886, and before that it was very rare. 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 aluminum.

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

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 get one out 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 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.

Bauxite is complex connection 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.

Transportation of raw materials is a separate part of the whole 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.

  1. 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.
  2. The second section of the preparatory workshop supplies prepared ore and additional additives for further processing.
  1. 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).

  1. 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.
  2. 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.

Difficult technological process requires large quantity 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!

The main aluminum deposits are concentrated in regions with 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

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

In our country there are several rich deposits of aluminum ores, concentrated in the Urals, and in 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.

Leaders in field development – Joint-Stock Company"Sevuralboxytruda", JSC Baksitogorsk Alumina, 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.

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%.

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.

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.

Today, aluminum produced from various ores, one of the popular materials that makes it possible to obtain durable and lightweight products that are not susceptible to corrosion. No alternatives to the metal have yet been found, and in the coming decades the volumes of ore mining and smelting will only increase.

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 sintering, a lot of red mud still remains in the dump, rational use 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 received from best use waste 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 would be complex use 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 nearby 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 elements, as well as by selecting more electrically conductive electrolytes (the resistance of cryolite is too high and great amount 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.

Plays a major role in reducing energy consumption service staff electrolysis workshops. 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.

The advanced teams of the electrolysis shops of aluminum smelters studied theoretical basis process and the characteristics of the baths they serve, carefully monitoring the progress of the process, they 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...

There are a large number of minerals and rocks containing aluminum, but only a few of them can be used to produce aluminum metal. Bauxite is the most widely used aluminum raw material. , Moreover, first, an intermediate product - alumina (Al 2 0 3) - is extracted from the ores, and then metallic aluminum is obtained from the alumina by electrolytic means. As A. r. nepheline-syenite are used (see Nepheline syenite) , as well as nepheline-apatite rocks, which simultaneously serve as a source of phosphates. Alunite rocks can serve as mineral raw materials for the production of aluminum (see Alunite) , leucite lavas (mineral Leucite), Labradorites, Anorthosites , high-alumina clays and kaolins, kyanite, sillimanite and andalusite shales.

In capitalist and developing countries, practically only bauxite is used to produce aluminum. In the USSR, in addition to bauxite, nepheline-syenite and nepheline-apatite rocks have acquired important practical significance.


Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

  • Aluminum monopolies
  • Aluminum alloys

See what "Aluminum ores" are in other dictionaries:

    Aluminum ores- (a. aluminum ores; n. Aluminumerze, Aluerze; f. minerais d aluminum; i. minerales de aluminum) natural mineral formations containing Aluminum in such compounds and concentrations, at which their industrial properties. technical use... ... Geological encyclopedia

    ALUMINUM ORES- rocks, raw materials for aluminum production. Mainly bauxite; Aluminum ores also include nepheline syenite, alunite, nepheline apatite rocks, etc... Big encyclopedic Dictionary

    aluminum ores- rocks, raw materials for aluminum production. Mainly bauxite; Aluminum ores also include nepheline syenite, alunite, nepheline apatite rocks, etc. * * * ALUMINUM ORES ALUMINUM ORES, rocks, raw materials for the production of... ... encyclopedic Dictionary

    aluminum ores- ores containing Al in such compounds and concentrations at which their industrial use is technically possible and economically feasible. The most common Al raw materials are bauxite, alunite and... ...

    ALUMINUM ORES- horn rocks, raw materials for aluminum production. In the main bauxite; to A. r. also include nepheline syenites, alunite, nepheline apatite rocks, etc... Natural science. encyclopedic Dictionary

    ferrous metal ores- ores that are the raw material base of the World Cup; including Fe, Mn and Cr ores (See Iron ores, Manganese ores and Chromium ores); See also: Commercial ores, siderite ores... Encyclopedic Dictionary of Metallurgy

    non-ferrous metal ores- ores that are the raw materials of CM, including a wide group of Al, polymetallic (containing Pb, Zn and other metals), Cu, Ni, Co, Sn, W, Mo, Ti ores. A specific feature of non-ferrous metal ores is their complex... ... Encyclopedic Dictionary of Metallurgy

    rare earth metal ores- natural mineral formations containing rare earth metals in the form of their own minerals or isomorphic impurities in some other minerals. Izv > 70 own rare earth minerals and about 280 minerals in which rare earth metals are included as ... Encyclopedic Dictionary of Metallurgy

    rare metal ores- natural formations containing RE in the form of independent minerals or isomorphic impurities in other ore and vein minerals in quantities sufficient for their profitable industrial extraction. RE is considered to be... ... Encyclopedic Dictionary of Metallurgy

    radioactive metal ores- natural mineral formations containing radioactive metals (U, Th, etc.) in such compounds and concentrations at which their extraction is technically possible and economically feasible. Industrial significance... ... Encyclopedic Dictionary of Metallurgy