Aluminum base. Aluminum

Aluminum- an element of the main subgroup of the third group of the third period of the periodic system of chemical elements of D.I. Mendeleev, atomic number 13. Denoted by the symbol Al (Aluminium). Belongs to the group of light metals. The most common metal and the third most abundant (after oxygen and silicon) chemical element in the earth's crust.

The simple substance aluminum (CAS number: 7429-90-5) is a lightweight, paramagnetic silver-white metal that can be easily formed, cast, and machined. 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.

According to some biological studies, the intake of aluminum in the human body was considered a factor in the development of Alzheimer's disease, but these studies were later criticized and the conclusion about the connection between one and the other was refuted.

Story

Aluminum was first obtained by Hans Oersted in 1825 by the action of potassium amalgam on aluminum chloride followed by distillation of mercury.

Receipt

The modern production method was developed independently by the American Charles Hall and the Frenchman Paul Héroux. It consists of dissolving aluminum oxide Al 2 O 3 in a melt of cryolite Na 3 AlF 6 followed by electrolysis using graphite electrodes. This production method requires a lot of electricity, and therefore became popular only in the 20th century.

To produce 1 ton of crude aluminum, 1.920 tons of alumina, 0.065 tons of cryolite, 0.035 tons of aluminum fluoride, 0.600 tons of anode mass and 17 thousand kWh of DC electricity are required.

Physical properties

The metal is silver-white in color, light, density - 2.7 g/cm³, melting point for technical aluminum - 658 °C, for high-purity aluminum - 660 °C, specific heat of fusion - 390 kJ/kg, boiling point - 2500 ° C, specific heat of evaporation - 10.53 MJ/kg, temporary resistance of cast aluminum - 10-12 kg/mm², deformable - 18-25 kg/mm², alloys - 38-42 kg/mm².

Brinell hardness is 24-32 kgf/mm², high ductility: technical - 35%, pure - 50%, rolled into thin sheets and even foil.

Aluminum has high electrical and thermal conductivity, 65% of the electrical conductivity of copper, and has high light reflectivity.

Aluminum forms alloys with almost all metals.

Being in nature

Natural aluminum consists almost entirely of a single stable isotope, 27Al, with traces of 26Al, a radioactive isotope with a half-life of 720,000 years produced in the atmosphere by bombardment of nuclei argon cosmic ray protons.

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

In nature, aluminum is found only in compounds (minerals). Some of them:

• Bauxite - Al 2 O 3. H 2 O (with impurities SiO 2, Fe 2 O 3, CaCO 3)
• Nephelines - KNa 3 4
• Alunites - KAl(SO 4) 2. 2Al(OH) 3
• Alumina (mixtures of kaolins with sand SiO 2, limestone CaCO 3, magnesite MgCO 3)
• Corundum - Al 2 O 3
• Feldspar (orthoclase) - K 2 O×Al 2 O 3 ×6SiO 2
• Kaolinite - Al 2 O 3 × 2SiO 2 × 2H 2 O
• Alunite - (Na,K) 2 SO 4 ×Al 2 (SO 4) 3 ×4Al(OH) 3
• Beryl - 3BeO. Al 2 O 3 . 6SiO2

Natural waters contain aluminum in the form of low-toxic chemical compounds, for example, aluminum fluoride. The type of cation or anion depends, first of all, on the acidity of the aqueous medium. Aluminum concentrations in surface water bodies in Russia range from 0.001 to 10 mg/l.

Chemical properties

Aluminum hydroxide

Under normal conditions, aluminum is covered with a thin and durable oxide film and therefore does not react with classical oxidizing agents: with H 2 O (t°); O 2, HNO 3 (without heating). Thanks to this, aluminum is practically not subject to corrosion and is therefore widely in demand in modern industry. However, when the oxide film is destroyed (for example, upon contact with solutions of ammonium salts NH 4 +, hot alkalis or as a result of amalgamation), aluminum acts as an active reducing metal.

Reacts easily with simple substances:

• with oxygen: 4Al + 3O 2 = 2Al 2 O 3
• with halogens: 2Al + 3Br 2 = 2AlBr 3
• reacts with other non-metals when heated:
  • with sulfur, forming aluminum sulfide: 2Al + 3S = Al 2 S 3
  • with nitrogen, forming aluminum nitride: 2Al + N 2 = 2AlN
  • with carbon, forming aluminum carbide: 4Al + 3C = Al 4 C 3

The method, invented almost simultaneously by Charles Hall in France and Paul Héroux in the USA in 1886 and based on the production of aluminum by electrolysis of alumina dissolved in molten cryolite, laid the foundation for the modern method of aluminum production. Since then, due to improvements in electrical engineering, aluminum production has improved. A notable contribution to the development of alumina production was made by Russian scientists K. I. Bayer, D. A. Penyakov, A. N. Kuznetsov, E. I. Zhukovsky, A. A. Yakovkin and others.

The first aluminum smelter in Russia was built in 1932 in Volkhov. The metallurgical industry of the USSR in 1939 produced 47.7 thousand tons of aluminum, another 2.2 thousand tons were imported.

In Russia, the de facto monopolist in aluminum production is Russian Aluminum OJSC, which accounts for about 13% of the world aluminum market and 16% of alumina.

The world's reserves of bauxite are practically limitless, that is, they are incommensurate with the dynamics of demand. Existing facilities can produce up to 44.3 million tons of primary aluminum per year. It should also be taken into account that in the future some of the applications of aluminum may be reoriented to the use of, for example, composite materials.

Application

A piece of aluminum and an American coin.

Widely used as a construction material. The main advantages of aluminum in this quality are lightness, malleability for stamping, corrosion resistance (in air, aluminum is instantly covered with a durable film of Al 2 O 3, which prevents its further oxidation), high thermal conductivity, and non-toxicity of its compounds. In particular, these properties have made aluminum extremely popular in the production of cookware, aluminum foil in the food industry and for packaging.

The main disadvantage of aluminum as a structural material is its low strength, so it is usually alloyed with a small amount of copper and magnesium - duralumin alloy.

The electrical conductivity of aluminum is only 1.7 times less than that of copper, while aluminum is approximately 2 times cheaper. Therefore, it is widely used in electrical engineering for the manufacture of wires, their shielding, and even in microelectronics for the manufacture of conductors in chips. The lower electrical conductivity of aluminum (37 1/ohm) compared to copper (63 1/ohm) is compensated by increasing the cross-section of aluminum conductors. The disadvantage of aluminum as an electrical material is its strong oxide film, which makes soldering difficult.

• Due to its complex of properties, it is widely used in heating equipment.
• Aluminum and its alloys retain strength at ultra-low temperatures. Due to this, it is widely used in cryogenic technology.
• High reflectivity, combined with low cost and ease of deposition, makes aluminum an ideal material for making mirrors.
• In the production of building materials as a gas-forming agent.
• Aluminizing imparts corrosion and scale resistance to steel and other alloys, such as piston internal combustion engine valves, turbine blades, oil platforms, heat exchange equipment, and also replaces galvanizing.
• Aluminum sulfide is used to produce hydrogen sulfide.
• Research is underway to develop foamed aluminum as an especially strong and lightweight material.

As a reducing agent

• As a component of thermite, mixtures for aluminothermy
• Aluminum is used to recover rare metals from their oxides or halides.

Aluminum alloys

The structural material usually used is not pure aluminum, but various alloys based on it.

— Aluminum-magnesium alloys have high corrosion resistance and are well welded; They are used, for example, to make the hulls of high-speed ships.

— Aluminum-manganese alloys are in many ways similar to aluminum-magnesium alloys.

— Aluminum-copper alloys (in particular, duralumin) can be subjected to heat treatment, which greatly increases their strength. Unfortunately, heat-treated materials cannot be welded, so aircraft parts are still connected with rivets. An alloy with a higher copper content is very similar in color to gold, and is sometimes used to imitate the latter.

— Aluminum-silicon alloys (silumins) are best suited for casting. Cases of various mechanisms are often cast from them.

— Complex alloys based on aluminum: avial.

— Aluminum goes into a superconducting state at a temperature of 1.2 Kelvin.

Aluminum as an additive to other alloys

Aluminum is an important component of many alloys. For example, in aluminum bronzes the main components are copper and aluminum. In magnesium alloys, aluminum is most often used as an additive. For the manufacture of spirals in electric heating devices, fechral (Fe, Cr, Al) is used (along with other alloys).

Jewelry

When aluminum was very expensive, a variety of jewelry was made from it. The fashion for them immediately passed when new technologies for its production appeared, which reduced the cost many times over. Nowadays, aluminum is sometimes used in the production of costume jewelry.

Glass making

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

Food industry

Aluminum is registered as a food additive E173.

Aluminum and its compounds in rocket technology

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

— Aluminum: fuel in rocket fuels. Used in the form of powder and suspensions in hydrocarbons, etc.
— Aluminum hydride
— Aluminum boranate
— Trimethylaluminum
— Triethylaluminum
— Tripropylaluminum

Theoretical characteristics of fuels formed by aluminum hydride with various oxidizers.

Aluminum in world culture

The poet Andrei Voznesensky wrote the poem “Autumn” in 1959, in which he used aluminum as an artistic image:
...And behind the window in the young frost
there are fields of aluminum...

Viktor Tsoi wrote the song “Aluminum Cucumbers” with the chorus:
Planting aluminum cucumbers
On a tarpaulin field
I plant aluminum cucumbers
On a tarpaulin field

Toxicity

It has a slight toxic effect, but many water-soluble inorganic aluminum compounds remain in a dissolved state for a long time and can have a harmful effect on humans and warm-blooded animals through drinking water. The most toxic are chlorides, nitrates, acetates, sulfates, etc. For humans, the following doses of aluminum compounds (mg/kg body weight) have a toxic effect when ingested: aluminum acetate - 0.2-0.4; aluminum hydroxide - 3.7-7.3; aluminum alum - 2.9. Primarily affects the nervous system (accumulates in nervous tissue, leading to severe disorders of the central nervous system). However, the neurotoxicity of aluminum has been studied since the mid-1960s, since the accumulation of the metal in the human body is prevented by its elimination mechanism. Under normal conditions, up to 15 mg of the element per day can be excreted in the urine. Accordingly, the greatest negative effect is observed in people with impaired renal excretory function.

Additional Information

— Aluminum hydroxide
— Encyclopedia about aluminum
— Aluminum connections
— International Aluminum Institute

Aluminum, Aluminum, Al (13)

Binders containing aluminum have been known since ancient times. However, alum (Latin Alumen or Alumin, German Alaun), which is mentioned, in particular, by Pliny, was understood in ancient times and in the Middle Ages as various substances. In Ruland's Alchemical Dictionary, the word Alumen, with the addition of various definitions, is given in 34 meanings. In particular, it meant antimony, Alumen alafuri - alkaline salt, Alumen Alcori - nitrum or alkali alum, Alumen creptum - tartar (tartar) of good wine, Alumen fascioli - alkali, Alumen odig - ammonia, Alumen scoriole - gypsum, etc. Lemery, the author of the famous “Dictionary of Simple Pharmaceutical Products” (1716), also provides a large list of varieties of alum.

Until the 18th century aluminum compounds (alum and oxide) could not be distinguished from other compounds similar in appearance. Lemery describes the alum as follows: “In 1754 r. Marggraf isolated from an alum solution (by the action of alkali) a precipitate of aluminum oxide, which he called “alum earth” (Alaunerde), and established its difference from other earths. Soon alum earth received the name alumina (Alumina or Alumine). In 1782, Lavoisier expressed the idea that aluminum was an oxide of an unknown element. In his Table of Simple Bodies, Lavoisier placed Alumine among the “simple bodies, salt-forming, earthy.” Here are synonyms for the name alumina: argile, alum. earth, foundation of alum. The word argilla, or argilla, as Lemery points out in his dictionary, comes from the Greek. pottery clay. Dalton in his “New System of Chemical Philosophy” gives a special sign for aluminum and gives a complex structural (!) formula for alum.

After the discovery of alkali metals using galvanic electricity, Davy and Berzelius unsuccessfully tried to isolate metallic aluminum from alumina in the same way. Only in 1825 was the problem solved by the Danish physicist Oersted using a chemical method. He passed chlorine through a hot mixture of alumina and coal, and the resulting anhydrous aluminum chloride was heated with potassium amalgam. After evaporation of mercury, writes Oersted, a metal similar in appearance to tin was obtained. Finally, in 1827, Wöhler isolated aluminum metal in a more efficient way - by heating anhydrous aluminum chloride with potassium metal.

Around 1807, Davy, who was trying to carry out the electrolysis of alumina, gave the name to the metal supposed to contain it aluminum (Alumium) or aluminum (Aluminum). The latter name has since become common in the USA, while in England and other countries the name Aluminum, later proposed by the same Davy, has been adopted. It is quite clear that all these names come from the Latin word alum (Alumen), about the origin of which there are different opinions, based on the evidence of various authors, dating back to antiquity.

A. M. Vasiliev, noting the unclear origin of this word, cites the opinion of a certain Isidore (obviously Isidore of Seville, a bishop who lived in 560 - 636, an encyclopedist who was engaged, in particular, in etymological research): “Alumen is called a lumen, so how it gives lumen (light, brightness) to paints when added during dyeing." However, this explanation, although very old, does not prove that the word alumen has precisely such origins. Here, only an accidental tautology is quite likely. Lemery (1716) in turn points out that the word alumen is related to the Greek (halmi), meaning salinity, brine, brine, etc.

Russian names for aluminum in the first decades of the 19th century. quite varied. Each of the authors of books on chemistry of this period obviously sought to propose its own title. Thus, Zakharov calls aluminum alumina (1810), Giese - alumium (1813), Strakhov - alum (1825), Iovsky - clay, Shcheglov - alumina (1830). In Dvigubsky's Store (1822 - 1830), alumina is called alumina, alumina, alumina (for example, phosphoric acid alumina), and the metal is called aluminum and aluminum (1824). Hess in the first edition of “Foundations of Pure Chemistry” (1831) uses the name alumina (Aluminium), and in the fifth edition (1840) - clay. However, he forms names for salts based on the term alumina, for example, alumina sulfate. Mendeleev in the first edition of “Fundamentals of Chemistry” (1871) uses the names aluminum and clay. In subsequent editions the word clay no longer appears.

As the lightest and most ductile metal, it has a wide range of uses. It is resistant to corrosion, has high electrical conductivity, and can easily withstand sudden temperature fluctuations. Another feature is that upon contact with air, a special film appears on its surface, which protects the metal.

All these, as well as other features, contributed to its active use. So, let's find out in more detail what the uses of aluminum are.

This structural metal is widely used. In particular, it was with its use that aircraft manufacturing, rocket science, the food industry and tableware manufacturing began their work. Thanks to its properties, aluminum allows for improved maneuverability of ships due to its lower weight.

Aluminum structures are on average 50% lighter than similar steel products.

Separately, it is worth mentioning the ability of metal to conduct current. This feature allowed it to become its main competitor. It is actively used in the production of microcircuits and in the field of microelectronics in general.

The most popular areas of use include:

• Aircraft manufacturing: pumps, engines, housings and other elements;
• Rocket science: as a combustible component for rocket fuel;
• Shipbuilding: hulls and deck superstructures;
• Electronics: wires, cables, rectifiers;
• Defense production: machine guns, tanks, aircraft, various installations;
• Construction: stairs, frames, finishing;
• Railway area: tanks for petroleum products, parts, frames for cars;
• Automotive industry: bumpers, radiators;
• Household: foil, dishes, mirrors, small appliances;

Its wide distribution is explained by the advantages of the metal, but it also has a significant drawback - low strength. To minimize it, magnesium is also added to the metal.

As you already understand, aluminum and its compounds are mainly used in electrical engineering (and simply technology), everyday life, industry, mechanical engineering, and aviation. Now we will talk about the use of aluminum metal in construction.

This video will tell you about the use of aluminum and its alloys:

Use in construction

The use of aluminum by humans in the field of construction is determined by its resistance to corrosion. This makes it possible to make structures from it that are planned to be used in aggressive environments, as well as outdoors.

Roofing materials

Aluminum is actively used for. This sheet material, in addition to its good decorative, load-bearing and enclosing features, also has an affordable price compared to other roofing materials. Moreover, such a roof does not require preventive inspection or repair, and its service life exceeds many existing materials.

By adding other metals to pure aluminum, you can get absolutely any decorative features. This roofing allows you to have a wide range of colors that fit perfectly into the overall style.

Window sashes

You can find aluminum among lanterns and window frames. If used for a similar purpose, it will prove to be an unreliable and short-lived material.

Steel will quickly become covered with corrosion, will have a large binding weight and will be inconvenient to open. In turn, aluminum structures do not have such disadvantages.

The video below will tell you about the properties and use of aluminum:

Wall panels

Aluminum panels are made from alloys of this metal and are used for exterior decoration of houses. They can take the form of ordinary stamped sheets or ready-made enclosing panels consisting of sheets, insulation and cladding. In any case, they retain heat inside the house as much as possible and, being light in weight, do not bear the load on the foundation.

Each chemical element can be considered from the point of view of three sciences: physics, chemistry and biology. And in this article we will try to characterize aluminum as accurately as possible. This is a chemical element located in the third group and third period, according to the periodic table. Aluminum is a metal that has average chemical reactivity. Amphoteric properties can also be observed in its compounds. The atomic mass of aluminum is twenty-six grams per mole.

Physical characteristics of aluminum

Under normal conditions it is a solid. The formula of aluminum is very simple. It consists of atoms (not combined into molecules), which are arranged using a crystal lattice into a solid substance. Aluminum color is silver-white. In addition, it has a metallic luster, like all other substances in this group. The color of aluminum used in industry may vary due to the presence of impurities in the alloy. This is a fairly light metal.

Its density is 2.7 g/cm3, that is, it is approximately three times lighter than iron. In this it can only be inferior to magnesium, which is even lighter than the metal in question. The hardness of aluminum is quite low. In it it is inferior to most metals. The hardness of aluminum is only two. Therefore, to strengthen it, harder ones are added to alloys based on this metal.

Aluminum melts at a temperature of only 660 degrees Celsius. And it boils when heated to a temperature of two thousand four hundred and fifty-two degrees Celsius. It is a very ductile and fusible metal. The physical characteristics of aluminum do not end there. I would also like to note that this metal has the best electrical conductivity after copper and silver.

Prevalence in nature

Aluminum, the technical characteristics of which we have just reviewed, is quite common in the environment. It can be observed in the composition of many minerals. The element aluminum is the fourth most abundant element in nature. It is almost nine percent in the earth's crust. The main minerals containing its atoms are bauxite, corundum, and cryolite. The first is a rock that consists of oxides of iron, silicon and the metal in question, and water molecules are also present in the structure. It has a heterogeneous color: fragments of gray, reddish-brown and other colors, which depend on the presence of various impurities. From thirty to sixty percent of this rock is aluminum, a photo of which can be seen above. In addition, corundum is a very common mineral in nature.

This is aluminum oxide. Its chemical formula is Al2O3. It can be red, yellow, blue or brown. Its hardness on the Mohs scale is nine. Varieties of corundum include the well-known sapphires and rubies, leucosapphires, as well as padparadscha (yellow sapphire).

Cryolite is a mineral with a more complex chemical formula. It consists of aluminum and sodium fluorides - AlF3.3NaF. It appears as a colorless or grayish stone with a low hardness of only three on the Mohs scale. In the modern world, it is synthesized artificially in laboratory conditions. It is used in metallurgy.

Aluminum can also be found in nature in clays, the main components of which are oxides of silicon and the metal in question, associated with water molecules. In addition, this chemical element can be observed in the composition of nephelines, the chemical formula of which is as follows: KNa34.

Receipt

The characteristics of aluminum include consideration of methods for its synthesis. There are several methods. Aluminum production using the first method occurs in three stages. The last of these is the electrolysis procedure on the cathode and carbon anode. To carry out such a process, aluminum oxide is required, as well as auxiliary substances such as cryolite (formula - Na3AlF6) and calcium fluoride (CaF2). In order for the process of decomposition of aluminum oxide dissolved in water to occur, it is necessary to heat it, together with molten cryolite and calcium fluoride, to a temperature of at least nine hundred and fifty degrees Celsius, and then pass a current of eighty thousand amperes and a voltage of five through these substances. eight volts. Thus, as a result of this process, aluminum will deposit on the cathode, and oxygen molecules will collect on the anode, which, in turn, oxidize the anode and convert it into carbon dioxide. Before this procedure, bauxite, in the form of which aluminum oxide is mined, is first purified of impurities, and also undergoes a process of dehydration.

The production of aluminum by the method described above is very common in metallurgy. There is also a method invented in 1827 by F. Wöhler. It lies in the fact that aluminum can be extracted using a chemical reaction between its chloride and potassium. Such a process can only be carried out by creating special conditions in the form of very high temperature and vacuum. So, from one mole of chloride and the same volume of potassium, one mole of aluminum and three moles as a by-product can be obtained. This reaction can be written in the form of the following equation: АІСІ3 + 3К = АІ + 3КІ. This method has not gained much popularity in metallurgy.

Characteristics of aluminum from a chemical point of view

As mentioned above, this is a simple substance that consists of atoms that are not combined into molecules. Almost all metals form similar structures. Aluminum has fairly high chemical activity and strong reducing properties. The chemical characterization of aluminum will begin with a description of its reactions with other simple substances, and then interactions with complex inorganic compounds will be described.

Aluminum and simple substances

These include, first of all, oxygen - the most common compound on the planet. Twenty-one percent of the Earth's atmosphere consists of it. The reaction of a given substance with any other is called oxidation or combustion. It usually occurs at high temperatures. But in the case of aluminum, oxidation is possible under normal conditions - this is how an oxide film is formed. If this metal is crushed, it will burn, releasing a large amount of energy in the form of heat. To carry out the reaction between aluminum and oxygen, these components are needed in a molar ratio of 4:3, resulting in two parts of the oxide.

This chemical interaction is expressed in the form of the following equation: 4АІ + 3О2 = 2АІО3. Reactions of aluminum with halogens, which include fluorine, iodine, bromine and chlorine, are also possible. The names of these processes come from the names of the corresponding halogens: fluorination, iodination, bromination and chlorination. These are typical addition reactions.

As an example, let us consider the interaction of aluminum with chlorine. This kind of process can only happen in the cold.

So, taking two moles of aluminum and three moles of chlorine, the result is two moles of chloride of the metal in question. The equation for this reaction is as follows: 2АІ + 3СІ = 2АІСІ3. In the same way you can obtain aluminum fluoride, its bromide and iodide.

The substance in question reacts with sulfur only when heated. To carry out the reaction between these two compounds, you need to take them in molar proportions of two to three, and one part of aluminum sulfide is formed. The reaction equation looks like this: 2Al + 3S = Al2S3.

In addition, at high temperatures, aluminum reacts with both carbon, forming carbide, and with nitrogen, forming nitride. The following equations of chemical reactions can be cited as an example: 4АІ + 3С = АІ4С3; 2Al + N2 = 2AlN.

Interaction with complex substances

These include water, salts, acids, bases, oxides. Aluminum reacts differently with all these chemical compounds. Let's take a closer look at each case.

Reaction with water

Aluminum reacts with the most common complex substance on Earth when heated. This only happens if the oxide film is first removed. As a result of the interaction, an amphoteric hydroxide is formed, and hydrogen is also released into the air. Taking two parts aluminum and six parts water, we get hydroxide and hydrogen in molar proportions of two to three. The equation for this reaction is written as follows: 2AI + 6H2O = 2AI(OH)3 + 3H2.

Interaction with acids, bases and oxides

Like other active metals, aluminum is capable of undergoing substitution reactions. In doing so, it can displace hydrogen from the acid or a cation of a more passive metal from its salt. As a result of such interactions, an aluminum salt is formed, and hydrogen is also released (in the case of an acid) or a pure metal (one that is less active than the one in question) precipitates. In the second case, the restorative properties mentioned above appear. An example is the interaction of aluminum with which aluminum chloride is formed and hydrogen is released into the air. This kind of reaction is expressed in the form of the following equation: 2АІ + 6НІ = 2АІСІ3 + 3Н2.

An example of the interaction of aluminum with salt is its reaction with Taking these two components, we will ultimately obtain pure copper, which will precipitate. Aluminum reacts in a unique way with acids such as sulfuric and nitric. For example, when aluminum is added to a dilute solution of nitrate acid in a molar ratio of eight parts to thirty, eight parts of nitrate of the metal in question are formed, three parts of nitric oxide and fifteen of water. The equation for this reaction is written as follows: 8Al + 30HNO3 = 8Al(NO3)3 + 3N2O + 15H2O. This process occurs only in the presence of high temperature.

If we mix aluminum and a weak solution of sulfate acid in molar proportions of two to three, we obtain sulfate of the metal in question and hydrogen in a ratio of one to three. That is, an ordinary substitution reaction will occur, as is the case with other acids. For clarity, we present the equation: 2Al + 3H2SO4 = Al2(SO4)3 + 3H2. However, with a concentrated solution of the same acid, everything is more complicated. Here, just as in the case of nitrate, a by-product is formed, but not in the form of an oxide, but in the form of sulfur and water. If we take the two components we need in a molar ratio of two to four, then the result will be one part each of the salt of the metal in question and sulfur, as well as four parts of water. This chemical interaction can be expressed using the following equation: 2Al + 4H2SO4 = Al2(SO4)3 + S + 4H2O.

In addition, aluminum is capable of reacting with alkali solutions. To carry out such a chemical interaction, you need to take two moles of the metal in question, the same amount of potassium, and also six moles of water. As a result, substances such as sodium or potassium tetrahydroxyaluminate are formed, as well as hydrogen, which is released in the form of a gas with a pungent odor in molar proportions of two to three. This chemical reaction can be represented in the form of the following equation: 2АІ + 2КОН + 6Н2О = 2К[АІ(ОН)4] + 3Н2.

And the last thing that needs to be considered is the patterns of interaction of aluminum with certain oxides. The most common and used case is the Beketov reaction. It, like many others discussed above, occurs only at high temperatures. So, to implement it, you need to take two moles of aluminum and one mole of ferrum oxide. As a result of the interaction of these two substances, we obtain aluminum oxide and free iron in quantities of one and two moles, respectively.

Use of the metal in question in industry

Note that the use of aluminum is a very common occurrence. First of all, the aviation industry needs it. Along with this, alloys based on the metal in question are also used. We can say that the average aircraft consists of 50% aluminum alloys, and its engine - 25%. Aluminum is also used in the manufacturing of wires and cables due to its excellent electrical conductivity. In addition, this metal and its alloys are widely used in the automotive industry. The bodies of cars, buses, trolleybuses, some trams, as well as conventional and electric train cars are made from these materials.

It is also used for smaller-scale purposes, for example, for the production of packaging for food and other products, and dishes. In order to make silver paint, you need powder of the metal in question. This paint is needed to protect the iron from corrosion. We can say that aluminum is the second most commonly used metal in industry after ferrum. Its compounds and itself are often used in the chemical industry. This is explained by the special chemical properties of aluminum, including its reducing properties and the amphoteric nature of its compounds. The hydroxide of the chemical element in question is necessary for water purification. In addition, it is used in medicine in the vaccine production process. It can also be found in some types of plastic and other materials.

Role in nature

As already written above, aluminum is found in large quantities in the earth's crust. It is especially important for living organisms. Aluminum is involved in the regulation of growth processes, forms connective tissues such as bone, ligament and others. Thanks to this microelement, the processes of regeneration of body tissues are carried out faster. Its deficiency is characterized by the following symptoms: impaired development and growth in children; in adults - chronic fatigue, decreased performance, impaired coordination of movements, decreased rates of tissue regeneration, weakening of muscles, especially in the extremities. This phenomenon can occur if you eat too few foods containing this microelement.

However, a more common problem is excess aluminum in the body. In this case, the following symptoms are often observed: nervousness, depression, sleep disturbances, decreased memory, stress resistance, softening of the musculoskeletal system, which can lead to frequent fractures and sprains. With a long-term excess of aluminum in the body, problems often arise in the functioning of almost every organ system.

A number of reasons can lead to this phenomenon. First of all, scientists have long proven that utensils made from the metal in question are unsuitable for cooking food in them, since at high temperatures some of the aluminum gets into the food, and as a result, you consume much more of this microelement than the body needs.

The second reason is the regular use of cosmetics containing the metal in question or its salts. Before using any product, you should carefully read its composition. Cosmetics are no exception.

The third reason is taking medications that contain a lot of aluminum for a long time. As well as improper use of vitamins and food additives that contain this microelement.

Now let's figure out what products contain aluminum in order to regulate your diet and organize your menu correctly. First of all, these are carrots, processed cheeses, wheat, alum, potatoes. Avocados and peaches are recommended fruits. In addition, white cabbage, rice, and many medicinal herbs are rich in aluminum. Also, cations of the metal in question may be contained in drinking water. To avoid high or low levels of aluminum in the body (as well as any other trace element), you need to carefully monitor your diet and try to make it as balanced as possible.

There is a lot of aluminum in the earth's crust: 8.6% by weight. It ranks first among all metals and third among other elements (after oxygen and silicon). There is twice as much aluminum as iron, and 350 times more than copper, zinc, chromium, tin and lead combined! As he wrote more than 100 years ago in his classic textbook Basics of Chemistry D.I. Mendeleev, of all metals, “aluminum is the most common in nature; It is enough to point out that it is part of clay to make clear the universal distribution of aluminum in the earth’s crust. Aluminum, or alum metal (alumen), is also called clay because it is found in clay.”

The most important aluminum mineral is bauxite, a mixture of the basic oxide AlO(OH) and hydroxide Al(OH) 3. The largest bauxite deposits are located in Australia, Brazil, Guinea and Jamaica; industrial production is also carried out in other countries. Alunite (alum stone) (Na,K) 2 SO 4 ·Al 2 (SO 4) 3 ·4Al(OH) 3 and nepheline (Na,K) 2 O·Al 2 O 3 ·2SiO 2 are also rich in aluminum. In total, more than 250 minerals are known that contain aluminum; most of them are aluminosilicates, from which the earth’s crust is mainly formed. When they weather, clay is formed, the basis of which is the mineral kaolinite Al 2 O 3 · 2SiO 2 · 2H 2 O. Iron impurities usually color the clay brown, but there is also white clay - kaolin, which is used to make porcelain and earthenware products.

Occasionally, an exceptionally hard (second only to diamond) mineral corundum is found - crystalline oxide Al 2 O 3, often colored by impurities in different colors. Its blue variety (an admixture of titanium and iron) is called sapphire, the red one (an admixture of chromium) is called ruby. Various impurities can also color the so-called noble corundum green, yellow, orange, purple and other colors and shades.

Until recently, it was believed that aluminum, as a highly active metal, could not occur in nature in a free state, but in 1978, native aluminum was discovered in the rocks of the Siberian Platform - in the form of thread-like crystals only 0.5 mm long (with a thread thickness of several micrometers). Native aluminum was also discovered in lunar soil brought to Earth from the regions of the Seas of Crisis and Abundance. It is believed that aluminum metal can be formed by condensation from gas. It is known that when aluminum halides - chloride, bromide, fluoride - are heated, they can evaporate with greater or less ease (for example, AlCl 3 sublimes already at 180 ° C). With a strong increase in temperature, aluminum halides decompose, transforming into a state with a lower metal valency, for example, AlCl. When such a compound condenses with a decrease in temperature and the absence of oxygen, a disproportionation reaction occurs in the solid phase: some of the aluminum atoms are oxidized and pass into the usual trivalent state, and some are reduced. Monivalent aluminum can only be reduced to metal: 3AlCl ® 2Al + AlCl 3 . This assumption is also supported by the thread-like shape of native aluminum crystals. Typically, crystals of this structure are formed due to rapid growth from the gas phase. It is likely that microscopic aluminum nuggets in the lunar soil were formed in a similar way.

The name aluminum comes from the Latin alumen (genus aluminis). This was the name of alum, double potassium-aluminum sulfate KAl(SO 4) 2 ·12H 2 O), which was used as a mordant for dyeing fabrics. The Latin name probably goes back to the Greek “halme” - brine, salt solution. It is curious that in England aluminum is aluminum, and in the USA it is aluminum.

Many popular books on chemistry contain a legend that a certain inventor, whose name has not been preserved by history, brought to the Emperor Tiberius, who ruled Rome in 14–27 AD, a bowl made of a metal resembling the color of silver, but lighter. This gift cost the master his life: Tiberius ordered his execution and the destruction of the workshop, because he was afraid that the new metal could depreciate the value of silver in the imperial treasury.

This legend is based on a story by Pliny the Elder, a Roman writer and scholar, author Natural history– encyclopedia of natural science knowledge of ancient times. According to Pliny, the new metal was obtained from "clayey earth." But clay does contain aluminum.

Modern authors almost always make a reservation that this whole story is nothing more than a beautiful fairy tale. And this is not surprising: aluminum in rocks is extremely tightly bound to oxygen, and a lot of energy must be spent to release it. However, recently new data have appeared on the fundamental possibility of obtaining metallic aluminum in ancient times. As spectral analysis showed, the decorations on the tomb of the Chinese commander Zhou-Zhu, who died at the beginning of the 3rd century. AD, are made of an alloy consisting of 85% aluminum. Could the ancients have obtained free aluminum? All known methods (electrolysis, reduction with metallic sodium or potassium) are automatically eliminated. Could native aluminum be found in ancient times, like, for example, nuggets of gold, silver, and copper? This is also excluded: native aluminum is a rare mineral that is found in insignificant quantities, so the ancient craftsmen could not find and collect such nuggets in the required quantity.

However, another explanation for Pliny's story is possible. Aluminum can be recovered from ores not only with the help of electricity and alkali metals. There is a reducing agent available and widely used since ancient times - coal, with the help of which the oxides of many metals are reduced to free metals when heated. In the late 1970s, German chemists decided to test whether aluminum could have been produced in ancient times by reduction with coal. They heated a mixture of clay with coal powder and table salt or potash (potassium carbonate) in a clay crucible to red heat. Salt was obtained from sea water, and potash from plant ash, in order to use only those substances and methods that were available in ancient times. After some time, slag with aluminum balls floated to the surface of the crucible! The metal yield was small, but it is possible that it was in this way that the ancient metallurgists could obtain the “metal of the 20th century.”

Properties of aluminum.

The color of pure aluminum resembles silver; it is a very light metal: its density is only 2.7 g/cm 3 . The only metals lighter than aluminum are alkali and alkaline earth metals (except barium), beryllium and magnesium. Aluminum also melts easily - at 600 ° C (thin aluminum wire can be melted on a regular kitchen burner), but it boils only at 2452 ° C. In terms of electrical conductivity, aluminum is in 4th place, second only to silver (it is in first place), copper and gold, which, given the cheapness of aluminum, is of great practical importance. The thermal conductivity of metals changes in the same order. It is easy to verify the high thermal conductivity of aluminum by dipping an aluminum spoon into hot tea. And one more remarkable property of this metal: its smooth, shiny surface perfectly reflects light: from 80 to 93% in the visible region of the spectrum, depending on the wavelength. In the ultraviolet region, aluminum has no equal in this regard, and only in the red region is it slightly inferior to silver (in the ultraviolet, silver has a very low reflectivity).

Pure aluminum is a fairly soft metal - almost three times softer than copper, so even relatively thick aluminum plates and rods are easy to bend, but when aluminum forms alloys (there are a huge number of them), its hardness can increase tenfold.

The characteristic oxidation state of aluminum is +3, but due to the presence of unfilled 3 R- and 3 d-orbitals, aluminum atoms can form additional donor-acceptor bonds. Therefore, the Al 3+ ion with a small radius is very prone to complex formation, forming a variety of cationic and anionic complexes: AlCl 4 –, AlF 6 3–, 3+, Al(OH) 4 –, Al(OH) 6 3–, AlH 4 – and many others. Complexes with organic compounds are also known.

The chemical activity of aluminum is very high; in the series of electrode potentials it stands immediately behind magnesium. At first glance, such a statement may seem strange: after all, an aluminum pan or spoon is quite stable in the air and does not collapse in boiling water. Aluminum, unlike iron, does not rust. It turns out that when exposed to air, the metal is covered with a colorless, thin but durable “armor” of oxide, which protects the metal from oxidation. So, if you introduce a thick aluminum wire or plate 0.5–1 mm thick into the burner flame, the metal melts, but the aluminum does not flow, since it remains in a bag of its oxide. If you deprive aluminum of its protective film or make it loose (for example, by immersing it in a solution of mercury salts), aluminum will immediately reveal its true essence: already at room temperature it will begin to react vigorously with water, releasing hydrogen: 2Al + 6H 2 O ® 2Al(OH) 3 + 3H 2 . In air, aluminum, stripped of its protective film, turns into loose oxide powder right before our eyes: 2Al + 3O 2 ® 2Al 2 O 3 . Aluminum is especially active in a finely crushed state; When blown into a flame, aluminum dust burns instantly. If you mix aluminum dust with sodium peroxide on a ceramic plate and drop water on the mixture, the aluminum also flares up and burns with a white flame.

The very high affinity of aluminum for oxygen allows it to “take away” oxygen from the oxides of a number of other metals, reducing them (aluminothermy method). The most famous example is the thermite mixture, which, when burned, releases so much heat that the resulting iron melts: 8Al + 3Fe 3 O 4 ® 4Al 2 O 3 + 9Fe. This reaction was discovered in 1856 by N.N. Beketov. In this way, Fe 2 O 3, CoO, NiO, MoO 3, V 2 O 5, SnO 2, CuO, and a number of other oxides can be reduced to metals. When reducing Cr 2 O 3, Nb 2 O 5, Ta 2 O 5, SiO 2, TiO 2, ZrO 2, B 2 O 3 with aluminum, the heat of reaction is not enough to heat the reaction products above their melting point.

Aluminum easily dissolves in dilute mineral acids to form salts. Concentrated nitric acid, oxidizing the surface of aluminum, promotes thickening and strengthening of the oxide film (the so-called passivation of the metal). Aluminum treated in this way does not react even with hydrochloric acid. Using electrochemical anodic oxidation (anodizing), a thick film can be created on the surface of aluminum, which can be easily painted in different colors.

The displacement of less active metals by aluminum from solutions of salts is often hindered by a protective film on the surface of aluminum. This film is quickly destroyed by copper chloride, so the reaction 3CuCl 2 + 2Al ® 2AlCl 3 + 3Cu occurs easily, which is accompanied by strong heating. In strong alkali solutions, aluminum easily dissolves with the release of hydrogen: 2Al + 6NaOH + 6H 2 O ® 2Na 3 + 3H 2 (other anionic hydroxo complexes are also formed). The amphoteric nature of aluminum compounds is also manifested in the easy dissolution of its freshly precipitated oxide and hydroxide in alkalis. Crystalline oxide (corundum) is very resistant to acids and alkalis. When fused with alkalis, anhydrous aluminates are formed: Al 2 O 3 + 2NaOH ® 2NaAlO 2 + H 2 O. Magnesium aluminate Mg(AlO 2) 2 is a semi-precious spinel stone, usually colored with impurities in a wide variety of colors.

The reaction of aluminum with halogens occurs rapidly. If a thin aluminum wire is introduced into a test tube with 1 ml of bromine, then after a short time the aluminum ignites and burns with a bright flame. The reaction of a mixture of aluminum and iodine powders is initiated by a drop of water (water with iodine forms an acid that destroys the oxide film), after which a bright flame appears with clouds of violet iodine vapor. Aluminum halides in aqueous solutions have an acidic reaction due to hydrolysis: AlCl 3 + H 2 O Al(OH)Cl 2 + HCl.

The reaction of aluminum with nitrogen occurs only above 800 ° C with the formation of nitride AlN, with sulfur - at 200 ° C (sulfide Al 2 S 3 is formed), with phosphorus - at 500 ° C (phosphide AlP is formed). When boron is added to molten aluminum, borides of the composition AlB 2 and AlB 12 are formed - refractory compounds resistant to acids. Hydride (AlH) x (x = 1.2) is formed only in vacuum at low temperatures in the reaction of atomic hydrogen with aluminum vapor. AlH 3 hydride, stable in the absence of moisture at room temperature, is obtained in a solution of anhydrous ether: AlCl 3 + LiH ® AlH 3 + 3LiCl. With an excess of LiH, salt-like lithium aluminum hydride LiAlH 4 is formed - a very strong reducing agent used in organic syntheses. It instantly decomposes with water: LiAlH 4 + 4H 2 O ® LiOH + Al(OH) 3 + 4H 2.

Production of aluminum.

The documented discovery of aluminum occurred in 1825. This metal was first obtained by the Danish physicist Hans Christian Oersted, when he isolated it by the action of potassium amalgam on anhydrous aluminum chloride (obtained by passing chlorine through a hot mixture of aluminum oxide and coal). Having distilled off the mercury, Oersted obtained aluminum, although it was contaminated with impurities. In 1827, the German chemist Friedrich Wöhler obtained aluminum in powder form by reducing hexafluoroaluminate with potassium:

Na 3 AlF 6 + 3K ® Al + 3NaF + 3KF. Later he managed to obtain aluminum in the form of shiny metal balls. In 1854, the French chemist Henri Etienne Saint-Clair Deville developed the first industrial method for producing aluminum - by reducing the melt of tetrachloroaluminate with sodium: NaAlCl 4 + 3Na ® Al + 4NaCl. However, aluminum continued to be an extremely rare and expensive metal; it was not much cheaper than gold and 1500 times more expensive than iron (now only three times). A rattle was made from gold, aluminum and precious stones in the 1850s for the son of French Emperor Napoleon III. When a large ingot of aluminum produced by a new method was exhibited at the World Exhibition in Paris in 1855, it was looked upon as if it were a jewel. The upper part (in the form of a pyramid) of the Washington Monument in the US capital was made from precious aluminum. At that time, aluminum was not much cheaper than silver: in the USA, for example, in 1856 it was sold at a price of 12 dollars per pound (454 g), and silver for 15 dollars. In the 1st volume of the famous Brockhaus Encyclopedic Dictionary published in 1890, Efron said that “aluminum is still used primarily for the manufacture of... luxury goods.” By that time, only 2.5 tons of metal were mined annually throughout the world. Only towards the end of the 19th century, when an electrolytic method for producing aluminum was developed, its annual production began to amount to thousands of tons, and in the 20th century. – million tons. This transformed aluminum from a semi-precious metal to a widely available metal.

The modern method of producing aluminum was discovered in 1886 by a young American researcher, Charles Martin Hall. He became interested in chemistry as a child. Having found his father's old chemistry textbook, he began to diligently study it and carry out experiments, once even receiving a scolding from his mother for damaging the dinner tablecloth. And 10 years later he made an outstanding discovery that made him famous throughout the world.

As a student at age 16, Hall heard from his teacher, F. F. Jewett, that if someone could develop a cheap way to produce aluminum, that person would not only do a great service to humanity, but also make a huge fortune. Jewett knew what he was saying: he had previously trained in Germany, worked with Wöhler, and discussed with him the problems of producing aluminum. Jewett also brought a sample of the rare metal with him to America, which he showed to his students. Suddenly Hall declared publicly: “I will get this metal!”

Six years of hard work continued. Hall tried to obtain aluminum using different methods, but without success. Finally, he tried to extract this metal by electrolysis. At that time there were no power plants; current had to be generated using large homemade batteries from coal, zinc, nitric and sulfuric acids. Hall worked in a barn where he set up a small laboratory. He was helped by his sister Julia, who was very interested in her brother’s experiments. She preserved all his letters and work journals, which make it possible to literally trace the history of the discovery day by day. Here is an excerpt from her memoirs:

“Charles was always in a good mood, and even on the worst days he was able to laugh at the fate of unlucky inventors. In times of failure, he found solace at our old piano. In his home laboratory he worked for long hours without a break; and when he could leave the set up for a while, he would rush across our long house to play a little... I knew that, playing with such charm and feeling, he was constantly thinking about his work. And music helped him with this.”

The most difficult thing was to select an electrolyte and protect the aluminum from oxidation. After six months of exhausting labor, several small silver balls finally appeared in the crucible. Hall immediately ran to his former teacher to tell him about his success. “Professor, I got it!” he exclaimed, holding out his hand: in his palm lay a dozen small aluminum balls. This happened on February 23, 1886. And exactly two months later, on April 23 of the same year, the Frenchman Paul Héroux took out a patent for a similar invention, which he made independently and almost simultaneously (two other coincidences are also striking: both Hall and Héroux were born in 1863 and died in 1914).

Now the first balls of aluminum produced by Hall are kept at the American Aluminum Company in Pittsburgh as a national relic, and at his college there is a monument to Hall, cast from aluminum. Jewett subsequently wrote: “My most important discovery was the discovery of man. It was Charles M. Hall who, at the age of 21, discovered a method of reducing aluminum from ore, and thus made aluminum that wonderful metal which is now widely used throughout the world.” Jewett's prophecy came true: Hall received wide recognition and became an honorary member of many scientific societies. But his personal life was unsuccessful: the bride did not want to come to terms with the fact that her fiancé spends all his time in the laboratory, and broke off the engagement. Hall found solace in his native college, where he worked for the rest of his life. As Charles’s brother wrote, “College was his wife, his children, and everything else—his whole life.” Hall bequeathed the majority of his inheritance to the college - $5 million. Hall died of leukemia at the age of 51.

Hall's method made it possible to produce relatively inexpensive aluminum on a large scale using electricity. If from 1855 to 1890 only 200 tons of aluminum were obtained, then over the next decade, using Hall’s method, 28,000 tons of this metal were already obtained worldwide! By 1930, global annual aluminum production reached 300 thousand tons. Now more than 15 million tons of aluminum are produced annually. In special baths at a temperature of 960–970 ° C, a solution of alumina (technical Al 2 O 3) in molten cryolite Na 3 AlF 6, which is partially mined in the form of a mineral, and partially specially synthesized, is subjected to electrolysis. Liquid aluminum accumulates at the bottom of the bath (cathode), oxygen is released at the carbon anodes, which gradually burn. At low voltage (about 4.5 V), electrolysers consume huge currents - up to 250,000 A! One electrolyzer produces about a ton of aluminum per day. Production requires a lot of electricity: it takes 15,000 kilowatt-hours of electricity to produce 1 ton of metal. This amount of electricity is consumed by a large 150-apartment building for a whole month. Aluminum production is environmentally hazardous, since the atmospheric air is polluted with volatile fluorine compounds.

Application of aluminum.

Even D.I. Mendeleev wrote that “metallic aluminum, having great lightness and strength and low variability in air, is very suitable for some products.” Aluminum is one of the most common and cheapest metals. It is difficult to imagine modern life without it. No wonder aluminum is called the metal of the 20th century. It lends itself well to processing: forging, stamping, rolling, drawing, pressing. Pure aluminum is a fairly soft metal; It is used to make electrical wires, structural parts, food foil, kitchen utensils and “silver” paint. This beautiful and lightweight metal is widely used in construction and aviation technology. Aluminum reflects light very well. Therefore, it is used to make mirrors using the method of metal deposition in a vacuum.

In aircraft and mechanical engineering, in the manufacture of building structures, much harder aluminum alloys are used. One of the most famous is an alloy of aluminum with copper and magnesium (duralumin, or simply “duralumin”; the name comes from the German city of Duren). After hardening, this alloy acquires special hardness and becomes approximately 7 times stronger than pure aluminum. At the same time, it is almost three times lighter than iron. It is obtained by alloying aluminum with small additions of copper, magnesium, manganese, silicon and iron. Silumins are widely used - casting alloys of aluminum and silicon. High-strength, cryogenic (frost-resistant) and heat-resistant alloys are also produced. Protective and decorative coatings are easily applied to products made of aluminum alloys. The lightness and strength of aluminum alloys are especially useful in aviation technology. For example, helicopter rotors are made from an alloy of aluminum, magnesium and silicon. Relatively cheap aluminum bronze (up to 11% Al) has high mechanical properties, it is stable in sea water and even in dilute hydrochloric acid. From 1926 to 1957, coins in denominations of 1, 2, 3 and 5 kopecks were minted from aluminum bronze in the USSR.

Currently, a quarter of all aluminum is used for construction needs, the same amount is consumed by transport engineering, approximately 17% is spent on packaging materials and cans, and 10% in electrical engineering.

Many flammable and explosive mixtures also contain aluminum. Alumotol, a cast mixture of trinitrotoluene and aluminum powder, is one of the most powerful industrial explosives. Ammonal is an explosive substance consisting of ammonium nitrate, trinitrotoluene and aluminum powder. Incendiary compositions contain aluminum and an oxidizing agent - nitrate, perchlorate. Zvezdochka pyrotechnic compositions also contain powdered aluminum.

A mixture of aluminum powder with metal oxides (thermite) is used to produce certain metals and alloys, for welding rails, and in incendiary ammunition.

Aluminum has also found practical use as rocket fuel. To completely burn 1 kg of aluminum, almost four times less oxygen is required than for 1 kg of kerosene. In addition, aluminum can be oxidized not only by free oxygen, but also by bound oxygen, which is part of water or carbon dioxide. When aluminum “burns” in water, 8800 kJ is released per 1 kg of products; this is 1.8 times less than during combustion of metal in pure oxygen, but 1.3 times more than during combustion in air. This means that instead of dangerous and expensive compounds, simple water can be used as an oxidizer for such fuel. The idea of ​​using aluminum as a fuel was proposed back in 1924 by the domestic scientist and inventor F.A. Tsander. According to his plan, it is possible to use aluminum elements of a spacecraft as additional fuel. This bold project has not yet been practically implemented, but most currently known solid rocket fuels contain metallic aluminum in the form of fine powder. Adding 15% aluminum to the fuel can increase the temperature of combustion products by a thousand degrees (from 2200 to 3200 K); The rate of flow of combustion products from the engine nozzle also increases noticeably - the main energy indicator that determines the efficiency of rocket fuel. In this regard, only lithium, beryllium and magnesium can compete with aluminum, but all of them are much more expensive than aluminum.

Aluminum compounds are also widely used. Aluminum oxide is a refractory and abrasive (emery) material, a raw material for the production of ceramics. It is also used to make laser materials, watch bearings, and jewelry stones (artificial rubies). Calcined aluminum oxide is an adsorbent for purifying gases and liquids and a catalyst for a number of organic reactions. Anhydrous aluminum chloride is a catalyst in organic synthesis (Friedel-Crafts reaction), the starting material for the production of high-purity aluminum. Aluminum sulfate is used for water purification; reacting with the calcium bicarbonate it contains:

Al 2 (SO 4) 3 + 3Ca(HCO 3) 2 ® 2AlO(OH) + 3CaSO 4 + 6CO 2 + 2H 2 O, it forms oxide-hydroxide flakes, which, settling, capture and also sorb on the surface those in suspended impurities and even microorganisms in water. In addition, aluminum sulfate is used as a mordant for dyeing fabrics, tanning leather, preserving wood, and sizing paper. Calcium aluminate is a component of cementitious materials, including Portland cement. Yttrium aluminum garnet (YAG) YAlO 3 is a laser material. Aluminum nitride is a refractory material for electric furnaces. Synthetic zeolites (they belong to aluminosilicates) are adsorbents in chromatography and catalysts. Organoaluminum compounds (for example, triethylaluminum) are components of Ziegler-Natta catalysts, which are used for the synthesis of polymers, including high-quality synthetic rubber.

Ilya Leenson

Literature:

Tikhonov V.N. Analytical chemistry of aluminum. M., “Science”, 1971
Popular library of chemical elements. M., “Science”, 1983
Craig N.C. Charles Martin Hall and his Metal. J.Chem.Educ. 1986, vol. 63, no. 7
Kumar V., Milewski L. Charles Martin Hall and the Great Aluminum Revolution. J.Chem.Educ., 1987, vol. 64, no. 8

There is a lot of aluminum in the earth's crust: 8.6% by weight. It ranks first among all metals and third among other elements (after oxygen and silicon). There is twice as much aluminum as iron, and 350 times more than copper, zinc, chromium, tin and lead combined! As he wrote more than 100 years ago in his classic textbook Basics of Chemistry D.I. Mendeleev, of all metals, “aluminum is the most common in nature; It is enough to point out that it is part of clay to make clear the universal distribution of aluminum in the earth’s crust. Aluminum, or alum metal (alumen), is also called clay because it is found in clay.”

The most important aluminum mineral is bauxite, a mixture of the basic oxide AlO(OH) and hydroxide Al(OH) 3. The largest bauxite deposits are located in Australia, Brazil, Guinea and Jamaica; industrial production is also carried out in other countries. Alunite (alum stone) (Na,K) 2 SO 4 ·Al 2 (SO 4) 3 ·4Al(OH) 3 and nepheline (Na,K) 2 O·Al 2 O 3 ·2SiO 2 are also rich in aluminum. In total, more than 250 minerals are known that contain aluminum; most of them are aluminosilicates, from which the earth’s crust is mainly formed. When they weather, clay is formed, the basis of which is the mineral kaolinite Al 2 O 3 · 2SiO 2 · 2H 2 O. Iron impurities usually color the clay brown, but there is also white clay - kaolin, which is used to make porcelain and earthenware products.

Occasionally, an exceptionally hard (second only to diamond) mineral corundum is found - crystalline oxide Al 2 O 3, often colored by impurities in different colors. Its blue variety (an admixture of titanium and iron) is called sapphire, the red one (an admixture of chromium) is called ruby. Various impurities can also color the so-called noble corundum green, yellow, orange, purple and other colors and shades.

Until recently, it was believed that aluminum, as a highly active metal, could not occur in nature in a free state, but in 1978, native aluminum was discovered in the rocks of the Siberian Platform - in the form of thread-like crystals only 0.5 mm long (with a thread thickness of several micrometers). Native aluminum was also discovered in lunar soil brought to Earth from the regions of the Seas of Crisis and Abundance. It is believed that aluminum metal can be formed by condensation from gas. It is known that when aluminum halides - chloride, bromide, fluoride - are heated, they can evaporate with greater or less ease (for example, AlCl 3 sublimes already at 180 ° C). With a strong increase in temperature, aluminum halides decompose, transforming into a state with a lower metal valency, for example, AlCl. When such a compound condenses with a decrease in temperature and the absence of oxygen, a disproportionation reaction occurs in the solid phase: some of the aluminum atoms are oxidized and pass into the usual trivalent state, and some are reduced. Monivalent aluminum can only be reduced to metal: 3AlCl ® 2Al + AlCl 3 . This assumption is also supported by the thread-like shape of native aluminum crystals. Typically, crystals of this structure are formed due to rapid growth from the gas phase. It is likely that microscopic aluminum nuggets in the lunar soil were formed in a similar way.

The name aluminum comes from the Latin alumen (genus aluminis). This was the name of alum, double potassium-aluminum sulfate KAl(SO 4) 2 ·12H 2 O), which was used as a mordant for dyeing fabrics. The Latin name probably goes back to the Greek “halme” - brine, salt solution. It is curious that in England aluminum is aluminum, and in the USA it is aluminum.

Many popular books on chemistry contain a legend that a certain inventor, whose name has not been preserved by history, brought to the Emperor Tiberius, who ruled Rome in 14–27 AD, a bowl made of a metal resembling the color of silver, but lighter. This gift cost the master his life: Tiberius ordered his execution and the destruction of the workshop, because he was afraid that the new metal could depreciate the value of silver in the imperial treasury.

This legend is based on a story by Pliny the Elder, a Roman writer and scholar, author Natural history– encyclopedia of natural science knowledge of ancient times. According to Pliny, the new metal was obtained from "clayey earth." But clay does contain aluminum.

Modern authors almost always make a reservation that this whole story is nothing more than a beautiful fairy tale. And this is not surprising: aluminum in rocks is extremely tightly bound to oxygen, and a lot of energy must be spent to release it. However, recently new data have appeared on the fundamental possibility of obtaining metallic aluminum in ancient times. As spectral analysis showed, the decorations on the tomb of the Chinese commander Zhou-Zhu, who died at the beginning of the 3rd century. AD, are made of an alloy consisting of 85% aluminum. Could the ancients have obtained free aluminum? All known methods (electrolysis, reduction with metallic sodium or potassium) are automatically eliminated. Could native aluminum be found in ancient times, like, for example, nuggets of gold, silver, and copper? This is also excluded: native aluminum is a rare mineral that is found in insignificant quantities, so the ancient craftsmen could not find and collect such nuggets in the required quantity.

However, another explanation for Pliny's story is possible. Aluminum can be recovered from ores not only with the help of electricity and alkali metals. There is a reducing agent available and widely used since ancient times - coal, with the help of which the oxides of many metals are reduced to free metals when heated. In the late 1970s, German chemists decided to test whether aluminum could have been produced in ancient times by reduction with coal. They heated a mixture of clay with coal powder and table salt or potash (potassium carbonate) in a clay crucible to red heat. Salt was obtained from sea water, and potash from plant ash, in order to use only those substances and methods that were available in ancient times. After some time, slag with aluminum balls floated to the surface of the crucible! The metal yield was small, but it is possible that it was in this way that the ancient metallurgists could obtain the “metal of the 20th century.”

Properties of aluminum.

The color of pure aluminum resembles silver; it is a very light metal: its density is only 2.7 g/cm 3 . The only metals lighter than aluminum are alkali and alkaline earth metals (except barium), beryllium and magnesium. Aluminum also melts easily - at 600 ° C (thin aluminum wire can be melted on a regular kitchen burner), but it boils only at 2452 ° C. In terms of electrical conductivity, aluminum is in 4th place, second only to silver (it is in first place), copper and gold, which, given the cheapness of aluminum, is of great practical importance. The thermal conductivity of metals changes in the same order. It is easy to verify the high thermal conductivity of aluminum by dipping an aluminum spoon into hot tea. And one more remarkable property of this metal: its smooth, shiny surface perfectly reflects light: from 80 to 93% in the visible region of the spectrum, depending on the wavelength. In the ultraviolet region, aluminum has no equal in this regard, and only in the red region is it slightly inferior to silver (in the ultraviolet, silver has a very low reflectivity).

Pure aluminum is a fairly soft metal - almost three times softer than copper, so even relatively thick aluminum plates and rods are easy to bend, but when aluminum forms alloys (there are a huge number of them), its hardness can increase tenfold.

The characteristic oxidation state of aluminum is +3, but due to the presence of unfilled 3 R- and 3 d-orbitals, aluminum atoms can form additional donor-acceptor bonds. Therefore, the Al 3+ ion with a small radius is very prone to complex formation, forming a variety of cationic and anionic complexes: AlCl 4 –, AlF 6 3–, 3+, Al(OH) 4 –, Al(OH) 6 3–, AlH 4 – and many others. Complexes with organic compounds are also known.

The chemical activity of aluminum is very high; in the series of electrode potentials it stands immediately behind magnesium. At first glance, such a statement may seem strange: after all, an aluminum pan or spoon is quite stable in the air and does not collapse in boiling water. Aluminum, unlike iron, does not rust. It turns out that when exposed to air, the metal is covered with a colorless, thin but durable “armor” of oxide, which protects the metal from oxidation. So, if you introduce a thick aluminum wire or plate 0.5–1 mm thick into the burner flame, the metal melts, but the aluminum does not flow, since it remains in a bag of its oxide. If you deprive aluminum of its protective film or make it loose (for example, by immersing it in a solution of mercury salts), aluminum will immediately reveal its true essence: already at room temperature it will begin to react vigorously with water, releasing hydrogen: 2Al + 6H 2 O ® 2Al(OH) 3 + 3H 2 . In air, aluminum, stripped of its protective film, turns into loose oxide powder right before our eyes: 2Al + 3O 2 ® 2Al 2 O 3 . Aluminum is especially active in a finely crushed state; When blown into a flame, aluminum dust burns instantly. If you mix aluminum dust with sodium peroxide on a ceramic plate and drop water on the mixture, the aluminum also flares up and burns with a white flame.

The very high affinity of aluminum for oxygen allows it to “take away” oxygen from the oxides of a number of other metals, reducing them (aluminothermy method). The most famous example is the thermite mixture, which, when burned, releases so much heat that the resulting iron melts: 8Al + 3Fe 3 O 4 ® 4Al 2 O 3 + 9Fe. This reaction was discovered in 1856 by N.N. Beketov. In this way, Fe 2 O 3, CoO, NiO, MoO 3, V 2 O 5, SnO 2, CuO, and a number of other oxides can be reduced to metals. When reducing Cr 2 O 3, Nb 2 O 5, Ta 2 O 5, SiO 2, TiO 2, ZrO 2, B 2 O 3 with aluminum, the heat of reaction is not enough to heat the reaction products above their melting point.

Aluminum easily dissolves in dilute mineral acids to form salts. Concentrated nitric acid, oxidizing the surface of aluminum, promotes thickening and strengthening of the oxide film (the so-called passivation of the metal). Aluminum treated in this way does not react even with hydrochloric acid. Using electrochemical anodic oxidation (anodizing), a thick film can be created on the surface of aluminum, which can be easily painted in different colors.

The displacement of less active metals by aluminum from solutions of salts is often hindered by a protective film on the surface of aluminum. This film is quickly destroyed by copper chloride, so the reaction 3CuCl 2 + 2Al ® 2AlCl 3 + 3Cu occurs easily, which is accompanied by strong heating. In strong alkali solutions, aluminum easily dissolves with the release of hydrogen: 2Al + 6NaOH + 6H 2 O ® 2Na 3 + 3H 2 (other anionic hydroxo complexes are also formed). The amphoteric nature of aluminum compounds is also manifested in the easy dissolution of its freshly precipitated oxide and hydroxide in alkalis. Crystalline oxide (corundum) is very resistant to acids and alkalis. When fused with alkalis, anhydrous aluminates are formed: Al 2 O 3 + 2NaOH ® 2NaAlO 2 + H 2 O. Magnesium aluminate Mg(AlO 2) 2 is a semi-precious spinel stone, usually colored with impurities in a wide variety of colors.

The reaction of aluminum with halogens occurs rapidly. If a thin aluminum wire is introduced into a test tube with 1 ml of bromine, then after a short time the aluminum ignites and burns with a bright flame. The reaction of a mixture of aluminum and iodine powders is initiated by a drop of water (water with iodine forms an acid that destroys the oxide film), after which a bright flame appears with clouds of violet iodine vapor. Aluminum halides in aqueous solutions have an acidic reaction due to hydrolysis: AlCl 3 + H 2 O Al(OH)Cl 2 + HCl.

The reaction of aluminum with nitrogen occurs only above 800 ° C with the formation of nitride AlN, with sulfur - at 200 ° C (sulfide Al 2 S 3 is formed), with phosphorus - at 500 ° C (phosphide AlP is formed). When boron is added to molten aluminum, borides of the composition AlB 2 and AlB 12 are formed - refractory compounds resistant to acids. Hydride (AlH) x (x = 1.2) is formed only in vacuum at low temperatures in the reaction of atomic hydrogen with aluminum vapor. AlH 3 hydride, stable in the absence of moisture at room temperature, is obtained in a solution of anhydrous ether: AlCl 3 + LiH ® AlH 3 + 3LiCl. With an excess of LiH, salt-like lithium aluminum hydride LiAlH 4 is formed - a very strong reducing agent used in organic syntheses. It instantly decomposes with water: LiAlH 4 + 4H 2 O ® LiOH + Al(OH) 3 + 4H 2.

Production of aluminum.

The documented discovery of aluminum occurred in 1825. This metal was first obtained by the Danish physicist Hans Christian Oersted, when he isolated it by the action of potassium amalgam on anhydrous aluminum chloride (obtained by passing chlorine through a hot mixture of aluminum oxide and coal). Having distilled off the mercury, Oersted obtained aluminum, although it was contaminated with impurities. In 1827, the German chemist Friedrich Wöhler obtained aluminum in powder form by reducing hexafluoroaluminate with potassium:

Na 3 AlF 6 + 3K ® Al + 3NaF + 3KF. Later he managed to obtain aluminum in the form of shiny metal balls. In 1854, the French chemist Henri Etienne Saint-Clair Deville developed the first industrial method for producing aluminum - by reducing the melt of tetrachloroaluminate with sodium: NaAlCl 4 + 3Na ® Al + 4NaCl. However, aluminum continued to be an extremely rare and expensive metal; it was not much cheaper than gold and 1500 times more expensive than iron (now only three times). A rattle was made from gold, aluminum and precious stones in the 1850s for the son of French Emperor Napoleon III. When a large ingot of aluminum produced by a new method was exhibited at the World Exhibition in Paris in 1855, it was looked upon as if it were a jewel. The upper part (in the form of a pyramid) of the Washington Monument in the US capital was made from precious aluminum. At that time, aluminum was not much cheaper than silver: in the USA, for example, in 1856 it was sold at a price of 12 dollars per pound (454 g), and silver for 15 dollars. In the 1st volume of the famous Brockhaus Encyclopedic Dictionary published in 1890, Efron said that “aluminum is still used primarily for the manufacture of... luxury goods.” By that time, only 2.5 tons of metal were mined annually throughout the world. Only towards the end of the 19th century, when an electrolytic method for producing aluminum was developed, its annual production began to amount to thousands of tons, and in the 20th century. – million tons. This transformed aluminum from a semi-precious metal to a widely available metal.

The modern method of producing aluminum was discovered in 1886 by a young American researcher, Charles Martin Hall. He became interested in chemistry as a child. Having found his father's old chemistry textbook, he began to diligently study it and carry out experiments, once even receiving a scolding from his mother for damaging the dinner tablecloth. And 10 years later he made an outstanding discovery that made him famous throughout the world.

As a student at age 16, Hall heard from his teacher, F. F. Jewett, that if someone could develop a cheap way to produce aluminum, that person would not only do a great service to humanity, but also make a huge fortune. Jewett knew what he was saying: he had previously trained in Germany, worked with Wöhler, and discussed with him the problems of producing aluminum. Jewett also brought a sample of the rare metal with him to America, which he showed to his students. Suddenly Hall declared publicly: “I will get this metal!”

Six years of hard work continued. Hall tried to obtain aluminum using different methods, but without success. Finally, he tried to extract this metal by electrolysis. At that time there were no power plants; current had to be generated using large homemade batteries from coal, zinc, nitric and sulfuric acids. Hall worked in a barn where he set up a small laboratory. He was helped by his sister Julia, who was very interested in her brother’s experiments. She preserved all his letters and work journals, which make it possible to literally trace the history of the discovery day by day. Here is an excerpt from her memoirs:

“Charles was always in a good mood, and even on the worst days he was able to laugh at the fate of unlucky inventors. In times of failure, he found solace at our old piano. In his home laboratory he worked for long hours without a break; and when he could leave the set up for a while, he would rush across our long house to play a little... I knew that, playing with such charm and feeling, he was constantly thinking about his work. And music helped him with this.”

The most difficult thing was to select an electrolyte and protect the aluminum from oxidation. After six months of exhausting labor, several small silver balls finally appeared in the crucible. Hall immediately ran to his former teacher to tell him about his success. “Professor, I got it!” he exclaimed, holding out his hand: in his palm lay a dozen small aluminum balls. This happened on February 23, 1886. And exactly two months later, on April 23 of the same year, the Frenchman Paul Héroux took out a patent for a similar invention, which he made independently and almost simultaneously (two other coincidences are also striking: both Hall and Héroux were born in 1863 and died in 1914).

Now the first balls of aluminum produced by Hall are kept at the American Aluminum Company in Pittsburgh as a national relic, and at his college there is a monument to Hall, cast from aluminum. Jewett subsequently wrote: “My most important discovery was the discovery of man. It was Charles M. Hall who, at the age of 21, discovered a method of reducing aluminum from ore, and thus made aluminum that wonderful metal which is now widely used throughout the world.” Jewett's prophecy came true: Hall received wide recognition and became an honorary member of many scientific societies. But his personal life was unsuccessful: the bride did not want to come to terms with the fact that her fiancé spends all his time in the laboratory, and broke off the engagement. Hall found solace in his native college, where he worked for the rest of his life. As Charles’s brother wrote, “College was his wife, his children, and everything else—his whole life.” Hall bequeathed the majority of his inheritance to the college - $5 million. Hall died of leukemia at the age of 51.

Hall's method made it possible to produce relatively inexpensive aluminum on a large scale using electricity. If from 1855 to 1890 only 200 tons of aluminum were obtained, then over the next decade, using Hall’s method, 28,000 tons of this metal were already obtained worldwide! By 1930, global annual aluminum production reached 300 thousand tons. Now more than 15 million tons of aluminum are produced annually. In special baths at a temperature of 960–970 ° C, a solution of alumina (technical Al 2 O 3) in molten cryolite Na 3 AlF 6, which is partially mined in the form of a mineral, and partially specially synthesized, is subjected to electrolysis. Liquid aluminum accumulates at the bottom of the bath (cathode), oxygen is released at the carbon anodes, which gradually burn. At low voltage (about 4.5 V), electrolysers consume huge currents - up to 250,000 A! One electrolyzer produces about a ton of aluminum per day. Production requires a lot of electricity: it takes 15,000 kilowatt-hours of electricity to produce 1 ton of metal. This amount of electricity is consumed by a large 150-apartment building for a whole month. Aluminum production is environmentally hazardous, since the atmospheric air is polluted with volatile fluorine compounds.

Application of aluminum.

Even D.I. Mendeleev wrote that “metallic aluminum, having great lightness and strength and low variability in air, is very suitable for some products.” Aluminum is one of the most common and cheapest metals. It is difficult to imagine modern life without it. No wonder aluminum is called the metal of the 20th century. It lends itself well to processing: forging, stamping, rolling, drawing, pressing. Pure aluminum is a fairly soft metal; It is used to make electrical wires, structural parts, food foil, kitchen utensils and “silver” paint. This beautiful and lightweight metal is widely used in construction and aviation technology. Aluminum reflects light very well. Therefore, it is used to make mirrors using the method of metal deposition in a vacuum.

In aircraft and mechanical engineering, in the manufacture of building structures, much harder aluminum alloys are used. One of the most famous is an alloy of aluminum with copper and magnesium (duralumin, or simply “duralumin”; the name comes from the German city of Duren). After hardening, this alloy acquires special hardness and becomes approximately 7 times stronger than pure aluminum. At the same time, it is almost three times lighter than iron. It is obtained by alloying aluminum with small additions of copper, magnesium, manganese, silicon and iron. Silumins are widely used - casting alloys of aluminum and silicon. High-strength, cryogenic (frost-resistant) and heat-resistant alloys are also produced. Protective and decorative coatings are easily applied to products made of aluminum alloys. The lightness and strength of aluminum alloys are especially useful in aviation technology. For example, helicopter rotors are made from an alloy of aluminum, magnesium and silicon. Relatively cheap aluminum bronze (up to 11% Al) has high mechanical properties, it is stable in sea water and even in dilute hydrochloric acid. From 1926 to 1957, coins in denominations of 1, 2, 3 and 5 kopecks were minted from aluminum bronze in the USSR.

Currently, a quarter of all aluminum is used for construction needs, the same amount is consumed by transport engineering, approximately 17% is spent on packaging materials and cans, and 10% in electrical engineering.

Many flammable and explosive mixtures also contain aluminum. Alumotol, a cast mixture of trinitrotoluene and aluminum powder, is one of the most powerful industrial explosives. Ammonal is an explosive substance consisting of ammonium nitrate, trinitrotoluene and aluminum powder. Incendiary compositions contain aluminum and an oxidizing agent - nitrate, perchlorate. Zvezdochka pyrotechnic compositions also contain powdered aluminum.

A mixture of aluminum powder with metal oxides (thermite) is used to produce certain metals and alloys, for welding rails, and in incendiary ammunition.

Aluminum has also found practical use as rocket fuel. To completely burn 1 kg of aluminum, almost four times less oxygen is required than for 1 kg of kerosene. In addition, aluminum can be oxidized not only by free oxygen, but also by bound oxygen, which is part of water or carbon dioxide. When aluminum “burns” in water, 8800 kJ is released per 1 kg of products; this is 1.8 times less than during combustion of metal in pure oxygen, but 1.3 times more than during combustion in air. This means that instead of dangerous and expensive compounds, simple water can be used as an oxidizer for such fuel. The idea of ​​using aluminum as a fuel was proposed back in 1924 by the domestic scientist and inventor F.A. Tsander. According to his plan, it is possible to use aluminum elements of a spacecraft as additional fuel. This bold project has not yet been practically implemented, but most currently known solid rocket fuels contain metallic aluminum in the form of fine powder. Adding 15% aluminum to the fuel can increase the temperature of combustion products by a thousand degrees (from 2200 to 3200 K); The rate of flow of combustion products from the engine nozzle also increases noticeably - the main energy indicator that determines the efficiency of rocket fuel. In this regard, only lithium, beryllium and magnesium can compete with aluminum, but all of them are much more expensive than aluminum.

Aluminum compounds are also widely used. Aluminum oxide is a refractory and abrasive (emery) material, a raw material for the production of ceramics. It is also used to make laser materials, watch bearings, and jewelry stones (artificial rubies). Calcined aluminum oxide is an adsorbent for purifying gases and liquids and a catalyst for a number of organic reactions. Anhydrous aluminum chloride is a catalyst in organic synthesis (Friedel-Crafts reaction), the starting material for the production of high-purity aluminum. Aluminum sulfate is used for water purification; reacting with the calcium bicarbonate it contains:

Al 2 (SO 4) 3 + 3Ca(HCO 3) 2 ® 2AlO(OH) + 3CaSO 4 + 6CO 2 + 2H 2 O, it forms oxide-hydroxide flakes, which, settling, capture and also sorb on the surface those in suspended impurities and even microorganisms in water. In addition, aluminum sulfate is used as a mordant for dyeing fabrics, tanning leather, preserving wood, and sizing paper. Calcium aluminate is a component of cementitious materials, including Portland cement. Yttrium aluminum garnet (YAG) YAlO 3 is a laser material. Aluminum nitride is a refractory material for electric furnaces. Synthetic zeolites (they belong to aluminosilicates) are adsorbents in chromatography and catalysts. Organoaluminum compounds (for example, triethylaluminum) are components of Ziegler-Natta catalysts, which are used for the synthesis of polymers, including high-quality synthetic rubber.

Ilya Leenson

Literature:

Tikhonov V.N. Analytical chemistry of aluminum. M., “Science”, 1971
Popular library of chemical elements. M., “Science”, 1983
Craig N.C. Charles Martin Hall and his Metal. J.Chem.Educ. 1986, vol. 63, no. 7
Kumar V., Milewski L. Charles Martin Hall and the Great Aluminum Revolution. J.Chem.Educ., 1987, vol. 64, no. 8