Aluminum: chemical and physical properties
Metals are one of the most convenient materials to process. They also have their own leaders. For example, the basic properties of aluminum have been known to people for a long time. They are so suitable for everyday use that this metal has become very popular. What are the properties of aluminum as a simple substance and as an atom, we will consider in this article.
History of the discovery of aluminum
For a long time, man has known the compound of the metal in question - potassium alum. It was used as a means that could swell and bind together the components of the mixture; this was also necessary in the manufacture of leather products. The existence of aluminum oxide in its pure form became known in the 18th century, in its second half. However, no pure substance was obtained.
The scientist H. K. Ørsted was the first to isolate the metal from its chloride. It was he who treated the salt with potassium amalgam and isolated gray powder from the mixture, which was aluminum in its pure form.
Then it became clear that the chemical properties of aluminum are manifested in its high activity and strong reducing ability. Therefore, no one else worked with him for a long time.
However, in 1854, the Frenchman Deville was able to obtain metal ingots by electrolysis of the melt. This method is still relevant today. Especially mass production of valuable material began in the 20th century, when the problems of generating large amounts of electricity in enterprises were solved.
Today, this metal is one of the most popular and used in construction and the household industry.
General characteristics of the aluminum atom
If we characterize the element in question by its position in the periodic table, then several points can be distinguished.
- The serial number is 13.
- Located in the third small period, third group, main subgroup.
- Atomic mass - 26.98.
- The number of valence electrons is 3.
- The configuration of the outer layer is expressed by the formula 3s23p1.
- The name of the element is aluminum.
- Metallic properties are strongly expressed.
- It has no isotopes in nature; it exists only in one form, with a mass number of 27.
- The chemical symbol is AL, read as “aluminum” in formulas.
- The oxidation state is one, equal to +3.
The chemical properties of aluminum are fully confirmed by the electronic structure of its atom, because having a large atomic radius and low electron affinity, it is capable of acting as a strong reducing agent, like all active metals.
Aluminum as a simple substance: physical properties
If we talk about aluminum as a simple substance, then it is a silvery-white shiny metal. In air it quickly oxidizes and becomes covered with a dense oxide film. The same thing happens when exposed to concentrated acids.
The presence of such a feature makes products made of this metal resistant to corrosion, which, naturally, is very convenient for people. That is why aluminum is so widely used in construction. The properties of the substance are also interesting in that this metal is very light, yet durable and soft. The combination of such characteristics is not available to every substance.
There are several basic physical properties that are characteristic of aluminum.
- High degree of malleability and ductility. Light, strong and very thin foil is made from this metal, and it is also rolled into wire.
- Melting point - 660 0C.
- Boiling point - 2450 0C.
- Density - 2.7 g/cm3.
- The crystal lattice is volumetric face-centered, metal.
- Connection type: metal.
The physical and chemical properties of aluminum determine the areas of its application and use. If we talk about everyday aspects, then the characteristics we have already discussed above play a big role. As a lightweight, durable and anti-corrosion metal, aluminum is used in aircraft and shipbuilding. Therefore, these properties are very important to know.
Chemical properties of aluminum
From a chemical point of view, the metal in question is a strong reducing agent that is capable of exhibiting high chemical activity while being a pure substance. The main thing is to remove the oxide film. In this case, activity increases sharply.
The chemical properties of aluminum as a simple substance are determined by its ability to react with:
- acids;
- alkalis;
- halogens;
- gray.
It does not interact with water under normal conditions. In this case, of the halogens, without heating, it reacts only with iodine. Other reactions require temperature.
Examples can be given to illustrate the chemical properties of aluminum. Equations of reactions of interaction with:
- acids - AL + HCL = AlCL3 + H2;
- alkalis - 2Al + 6H2O + 2NaOH = Na[Al(OH)4] + 3H2;
- halogens - AL + Hal = ALHal3;
- gray - 2AL + 3S = AL2S3.
In general, the most important property of the substance in question is its high ability to restore other elements from their compounds.
Regenerative capacity
The reducing properties of aluminum are clearly visible in the reactions of interaction with oxides of other metals. It easily extracts them from the composition of the substance and allows them to exist in a simple form. For example: Cr2O3 + AL = AL2O3 + Cr.
In metallurgy, there is a whole method for producing substances based on similar reactions. It is called aluminothermy. Therefore, in the chemical industry this element is used specifically for the production of other metals.
Distribution in nature
In terms of prevalence among other metal elements, aluminum ranks first. It is contained in the earth's crust 8.8%. If we compare it with non-metals, then its place will be third, after oxygen and silicon.
Due to its high chemical activity, it is not found in pure form, but only as part of various compounds. For example, there are many known ores, minerals, and rocks that contain aluminum. However, it is extracted only from bauxite, the content of which in nature is not very high.
The most common substances containing the metal in question:
- feldspars;
- bauxite;
- granites;
- silica;
- aluminosilicates;
- basalts and others.
In small quantities, aluminum is necessarily found in the cells of living organisms. Some species of club mosses and marine inhabitants are capable of accumulating this element inside their bodies throughout their lives.
Receipt
The physical and chemical properties of aluminum make it possible to obtain it only in one way: by electrolysis of a melt of the corresponding oxide. However, this process is technologically complex. The melting point of AL2O3 exceeds 2000 0C. Because of this, it cannot be subjected to electrolysis directly. Therefore, proceed as follows.
- Bauxite is mined.
- They are cleaned of impurities, leaving only aluminum oxide.
- Then the cryolite is melted.
- Oxide is added there.
- This mixture is electrolyzed and pure aluminum and carbon dioxide are obtained.
The product yield is 99.7%. However, it is possible to obtain even purer metal, which is used for technical purposes.
Application
The mechanical properties of aluminum are not so good that it can be used in its pure form. Therefore, alloys based on this substance are most often used. There are many of these, you can name the most basic ones.
- Duralumin.
- Aluminum-manganese.
- Aluminum-magnesium.
- Aluminum-copper.
- Silumins.
- Avial.
Their main difference is, naturally, third-party additives. All of them are based on aluminum. Other metals make the material more durable, corrosion-resistant, wear-resistant and easy to process.
There are several main areas of application of aluminum, both in pure form and in the form of its compounds (alloys).
- For the production of wire and foil used in everyday life.
- Making dishes.
- Aircraft manufacturing.
- Shipbuilding.
- Construction and architecture.
- Space industry.
- Creation of reactors.
Together with iron and its alloys, aluminum is the most important metal. It was these two representatives of the periodic table that found the most extensive industrial application in human hands.
Properties of aluminum hydroxide
Hydroxide is the most common compound that aluminum forms. Its chemical properties are the same as those of the metal itself - it is amphoteric. This means that it is capable of exhibiting a dual nature, reacting with both acids and alkalis.
Aluminum hydroxide itself is a white gelatinous precipitate. It is easily obtained by reacting aluminum salts with alkali or ammonium hydroxide. When reacting with acids, this hydroxide gives the usual corresponding salt and water. If the reaction occurs with an alkali, then hydroxo complexes of aluminum are formed, in which its coordination number is 4. Example: Na[Al(OH)4] - sodium tetrahydroxoaluminate.
Source: https://FB.ru/article/190101/alyuminiy-svoystva-himicheskie-i-fizicheskie
Aluminum is the most common metal in the earth's crust:
Metals are a group of simple substances that have characteristic metallic properties. Some of them are valued higher than gold for their amazing characteristics, which allow them to be used in a variety of fields. Many metals are contained in the earth's crust in small quantities. But today we will look at what is the most common metal in the earth’s crust.
What do we know about aluminum?
Yes, aluminum is the most common metal. It was discovered in 1825 by the Danish scientist Oersted. However, as early as 500 BC, people used so-called aluminum alum. They were used as a mordant for dyeing fabrics and tanning leather.
Aluminum, similar in appearance to silver, was initially very valuable. This is due to the fact that it is quite difficult to obtain in its pure form. And it was not known that this is the most common metal in the earth’s crust. In the 19th century, between 1855 and 1890, only 200 tons of pure metal were obtained.
However, today geologists claim that 8% of the Earth's crust consists of aluminum. It is second only to oxygen and silicon in terms of its content in the earth’s crust. It is not found in free form in nature.
Aluminum was widely used in the countries of the USSR thanks to the developments of scientists. The discovered method for producing aluminum provided unlimited opportunities for the development of the aluminum industry. On its basis, they actively made tableware, which each of us saw in our grandmothers’ kitchens. The first satellite of the USSR was also made of aluminum alloy. It is also used in the electrical industry (cables, sockets, capacitors).
Basic properties of aluminum
The most common metal in the earth's crust has a number of properties that allow it to be actively used in metal structures. It is light, soft and easy to stamp.
Aluminum has high corrosion resistance. Upon contact with air, it becomes covered with a film that prevents its oxidation. It is non-toxic (if it does not enter the body in large quantities), and has high electrical and thermal conductivity. It is he who ensures the transmission of electricity on Earth.
However, the metal is not durable. Therefore, in the manufacture of metal structures, an alloy of aluminum with other metals - copper, magnesium - is often used. Such alloys are called duralumin.
The electrical conductivity of the metal can be compared to copper, but it is cheaper, so it has found wider use. One of the few disadvantages of aluminum is that it is difficult to solder due to its strong oxide film. By the way, it is highly flammable and if not for this oxide film, it would burn in air.
Aluminum is a precious metal
Interestingly, aluminum was highly valued in the 19th century. For a kilogram of metal they asked for about 3,000 francs. Therefore, jewelers actively made jewelry based on it. After all, the metal is easy to process, has a beautiful silver tint and allows you to give the product any shape.
However, after a few years it began to fall in price and soon went out of fashion. Many aluminum jewelry did not survive the depreciation of the metal. Today they are very rare.
More recently, aluminum became the main theme of an exhibition organized in Pittsburgh (Pennsylvania) at the Carnegie Museum. Interest in him appears again. The most common non-ferrous metal in the earth's crust today is used in the form of metal foam. This is the latest development, on the basis of which even ship hulls can be manufactured.
Harm of aluminum
Back in 1960, scientists discovered that high levels of aluminum were present in the brains of people suffering from Alzheimer's disease.
Recent studies have confirmed that metal causes accelerated aging of brain cells and causes degenerative neurological diseases. The low digestibility of aluminum gives a false impression of its safety for the body.
But in fact, long-term use of small doses of it eventually causes neurons in the brain and spinal cord to shut down.
Gold is the most commonly found precious metal
Gold is the most common noble metal in the earth's crust. Once upon a time, people knew only 2 precious metals - gold and silver. However, later the list expanded. Today the noble metals are the platinum group of metals. This group, in addition to platinum, also includes its elements - rhodium, osmium, ruthenium and iridium. By the way, iridium is the rarest metal in this group. Technetium is also recognized as noble, but due to radioactivity it was not included in the list of precious metals.
Gold, like other noble metals, has a number of unique properties. It shines in the open air, it is not harmed by prolonged exposure to water, as well as exposure to alkalis and acids, and high temperatures.
Gold is easy to process and has a high density. The metal is found in the form of nuggets, sand and in combination with other elements. However, gold is inferior to many metals in strength and stability.
Today it is far from the most expensive precious metal. Its price is $45 per 1 gram.
Source: https://www.syl.ru/article/370047/alyuminiy---samyiy-rasprostranennyiy-metall-v-zemnoy-kore
The history of the appearance of aluminum and the first practices of application
The metal, used in almost all spheres of social life, has a relatively short history of development: for the first time in the 16th century, Paracelsus began to solve the problem of its production.
The metal, used in almost all spheres of social life, has a relatively short history of development: for the first time in the 16th century, Paracelsus began to solve the problem of its production. It was he who called aluminum oxide “astringent”, that is, “alumen”.
The work of Paracelsus was continued in the 18th century by Andreas Marggraff; he raised in science the question of the possible properties of aluminum, but was unable to isolate it in its pure form.
How did the first ingot appear?
Humphry Davy, an English scientist, tried to obtain pure aluminum using electrolysis in 1808, and he also gave the substance its modern name. By 1825, in Denmark, Hans-Christian Oersted was able to isolate aluminum chloride, then he obtained a metal whose properties were very similar to those of tin.
The first ingot was the result of 18 years of work by the German scientist Friedrich Wöhler. In all subsequent years, attempts were made to discover cheap ways to obtain pure aluminum.
Since the metal was equal in price to traditional precious metals, French industrialists supplied it to the imperial court for the production of luxury goods and jewelry.
By the end of the 19th century, an American student and a French engineer simultaneously managed to achieve a cheap method of producing aluminum through electrolysis. Since large amounts of electricity were required, the first factories began to be built near the waterfalls.
Australian engineer Bayer made a significant contribution to the history of the development of the aluminum industry: he learned to produce alumina using economical technology, which is still used today. Alfred Wilm increased the strength of aluminum by smelting it with small additions of magnesium, copper and manganese.
By the 20th century, annual aluminum production reached 8 thousand tons.
Modernity: the influence of the aluminum industry on all areas of production
The metal in question is an indispensable component in architecture, advertising production, food industry, construction, design, medicine, etc., in particular, wide aluminum rod for sale (http://www.alfa-sous.ru/4/czvetnoj-metalloprokat/ 14/krug-alyuminievyij.html) occupies a leading position in demand. If we consider the overall prevalence of the substance, only iron is used in industry more than aluminum.
The achievements of the discoverers of the metal are in demand due to the unique properties of aluminum - it is very ductile and has impressive malleability parameters. Thanks to the oxide film, it is not afraid of corrosion, due to which the service life becomes definitely long. Positive properties are also non-toxicity, enhanced electrical conductivity, and ease of processing. Thanks to the advent of aluminum, aircraft and the space industry developed.
The metal still remains quite expensive, so the organization of aluminum recycling is of great importance for global industry. Throughout the country, people constantly bring disused household items, dishes, and wire to collection points for non-ferrous scrap, since the reward calculated for each kilogram is worthy of attention and effort.
Source: http://www.technoflax.com/istoriya-poyavleniya-alyuminiya-i-primenenie.html
Aluminum
Aluminum is a ductile and lightweight white metal coated with a silver matte oxide film. In the periodic system of D.I. Mendeleev, this chemical element is designated as Al (Aluminium) and is located in the main subgroup of group III, third period, under atomic number 13. You can buy aluminum on our website.
History of discovery
In the 16th century, the famous Paracelsus took the first step towards aluminum mining. From alum, he isolated “alum earth,” which contained the oxide of a then unknown metal. In the 18th century, the German chemist Andreas Marggraff returned to this experiment. He named the aluminum oxide “alumina,” which means “astringent” in Latin. At that time, the metal was not popular because it was not found in its pure form.
For many years, English, Danish and German scientists tried to isolate pure aluminum. In 1855, at the Paris World Exhibition, the metal aluminum created a sensation. Only luxury items and jewelry were made from it, since the metal was quite expensive. At the end of the 19th century, a more modern and cheaper method of producing aluminum appeared. In 1911, the first batch of duralumin, named after the city, was produced in Duren.
In 1919, the first airplane was created from this material.
Physical properties
Aluminum metal is characterized by high electrical conductivity, thermal conductivity, resistance to corrosion and frost, and ductility. It lends itself well to stamping, forging, drawing, and rolling. Aluminum can be welded well with various types of welding.
An important property is its low density of about 2.7 g/cm³.
The melting point is about 660°C. The mechanical, physicochemical and technological properties of aluminum depend on the presence and amount of impurities that worsen the properties of the pure metal.
The main natural impurities are silicon, iron, zinc, titanium and copper.
According to the degree of purification, aluminum is distinguished between high and technical purity. The practical difference is the difference in corrosion resistance to certain environments. The purer the metal, the more expensive it is. Technical aluminum is used for the production of alloys, rolled products and cable and wire products.
High purity metal is used for special purposes.
In terms of electrical conductivity, aluminum is second only to gold, silver and copper. And the combination of low density and high electrical conductivity allows it to compete with copper in the field of cable and wire products.
Long-term annealing improves electrical conductivity, while cold hardening worsens it.
The thermal conductivity of aluminum increases with increasing purity of the metal. Impurities of manganese, magnesium and copper reduce this property. In terms of thermal conductivity, aluminum is inferior only to copper and silver.
Due to this property, the metal is used in heat exchangers and cooling radiators.
Aluminum has a high specific heat capacity and heat of fusion. These figures are significantly higher than those of most metals.
The higher the purity of aluminum, the more it is able to reflect light from the surface. The metal is well polished and anodized.
Aluminum has a high affinity for oxygen and is covered in air with a thin, durable film of aluminum oxide. This film protects the metal from subsequent oxidation and provides its good anti-corrosion properties. Aluminum is resistant to atmospheric corrosion, sea and fresh water, and practically does not interact with organic acids, concentrated or diluted nitric acid.
Chemical properties
Aluminum is a fairly active amphoteric metal. Under normal conditions, a strong oxide film determines its durability. If the oxide film is destroyed, aluminum acts as an active reducing metal.
In a finely crushed state and at high temperatures, the metal interacts with oxygen. When heated, reactions occur with sulfur, phosphorus, nitrogen, carbon, and iodine. Under normal conditions, the metal reacts with chlorine and bromine. There is no reaction with hydrogen.
With metals, aluminum forms alloys containing intermetallic compounds - aluminides.
Provided that the oxide film is removed, vigorous interaction with water occurs. Reactions with dilute acids occur easily. Reactions with concentrated nitric and sulfuric acid occur when heated. Aluminum reacts easily with alkalis. Practical application in metallurgy has found the property of reducing metals from oxides and salts - aluminothermy reactions.
Let's look at how various aluminum products are used
Aluminum tape is a thin aluminum strip 0.3-2 mm thick, 50-1250 mm wide, which is supplied in rolls. The tape is used in the food, light, and refrigeration industries for the manufacture of cooling elements and radiators.
Round aluminum wire is used for the manufacture of cables and wires for electrical purposes, and rectangular for winding wires.
Aluminum pipes are durable and resistant in rural and urban industrial areas. They are used in finishing works, road construction, construction of cars, aircraft and ships, production of radiators, pipelines and gas tanks, installation of heating systems, main pipelines, gas pipelines, water pipelines.
Aluminum bushings are characterized by ease of processing, installation and operation. They are used for the end connection of metal cables.
An aluminum circle is a solid round section profile. This product is used for the manufacture of various designs.
Aluminum rod is used to make nuts, bolts, shafts, fasteners and spindles.
About 3 mg of aluminum enters the human body through food every day. The most metal is found in oatmeal, peas, wheat, and rice. Scientists have found that it promotes regeneration processes, stimulates the development and growth of tissues, and affects the activity of the digestive glands and enzymes.
Aluminum sheet
Aluminum plate
Aluminum ingots
Aluminum corners
Aluminum wire
When using aluminum cookware at home, you must remember that only neutral liquids can be stored and heated in it. If, for example, sour cabbage soup is cooked in such a container, then aluminum will enter the food and it will have an unpleasant “metallic” taste.
Aluminum is included in medications used for diseases of the kidneys and gastrointestinal tract.
Source: https://cu-prum.ru/alyuminij1.html
No. 13 Aluminum
Around 1807, Davy, who was trying to carry out the electrolysis of alumina, gave the name to the metal supposed to contain it, Alumium. Aluminum was first obtained by Hans Oersted in 1825 by the action of potassium amalgam on aluminum chloride followed by distillation of mercury. In 1827, Wöhler isolated aluminum metal in a more efficient way - by heating anhydrous aluminum chloride with potassium metal.
Being in nature, receiving:
In terms of prevalence in nature, it ranks 1st among metals and 3rd among elements, second only to oxygen and silicon. aluminum 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).
Corundum: Al2O3 - belongs to the class of simple oxides, and sometimes forms transparent precious crystals - sapphire, and, with the addition of chromium, ruby.
Accumulates in placers. Bauxite: Al2O3*nH2O - sedimentary aluminum ores. Contain a harmful impurity - SiO2. Bauxite serves as an important raw material for the production of aluminum, as well as paints and abrasives.
Kaolinite: Al2O3*2SiO2*2H2O is a mineral of the subclass of layered silicates, the main component of white, refractory, and porcelain clay.
The modern method for producing aluminum was developed independently by the American Charles Hall and the Frenchman Paul Héroux. It consists of dissolving aluminum oxide Al2O3 in molten cryolite Na3AlF3, 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 aluminum, 1.9 tons of alumina and 18 thousand kWh of electricity are required.
Physical properties:
The metal is silvery-white, lightweight, density 2.7 g/cm3, melting point 660°C, boiling point 2500°C. High ductility, rolled into thin sheets and even foil. Aluminum has high electrical and thermal conductivity and is highly reflective. Aluminum forms alloys with almost all metals.
Chemical properties:
Under normal conditions, aluminum is covered with a thin and durable oxide film and therefore does not react with classical oxidizing agents: with H2O (t°); O2, HNO3 (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 NH4+, hot alkalis or as a result of amalgamation), aluminum acts as an active reducing metal.
Reacts easily with simple substances: oxygen, halogens: 2Al + 3Br2 = 2AlBr3 With other non-metals, aluminum reacts when heated:
2Al + 3S = Al2S3 2Al + N2 = 2AlN
Aluminum is only capable of dissolving hydrogen, but does not react with it. With complex substances: aluminum reacts with alkalis (to form tetrahydroxoaluminates):
2Al + 2NaOH + 6H2O = 2Na[Al(OH)4] + 3H2
Easily dissolves in dilute and concentrated sulfuric acids:
2Al + 3H2SO4(dil) = Al2(SO4)3 + 3H2 2Al + 6H2SO4(conc) = Al2(SO4)3 + 3SO2 + 6H2O
Aluminum reduces metals from their oxides (aluminothermy): 8Al + 3Fe3O4 = 4Al2O3 + 9Fe
The most important connections:
Aluminum oxide , Al2O3: a white, hard, refractory substance.
Crystalline Al2O3 is chemically passive, amorphous is more active. Reacts slowly with acids and alkalis in solution, exhibiting amphoteric properties: Al2O3 + 6HCl(conc.) = 2AlCl3 + 3H2O Al2O3 + 2NaOH(conc.) + 3H2O = 2Na[Al(OH)4]
(NaAlO2 is formed in the alkali melt).
Aluminum hydroxide , Al(OH)3: white amorphous (gel-like) or crystalline. Practically insoluble in water. When heated, it decomposes step by step. It exhibits amphoteric, equally pronounced acidic and basic properties. When fused with NaOH, NaAlO2 is formed.
To obtain the Al(OH)3 precipitate, alkali is usually not used (due to the ease of transition of the precipitate into solution), but they act on aluminum salts with an ammonia solution - at room temperature Al(OH)3
Aluminum salts .
Aluminum salts and strong acids are highly soluble in water and undergo significant cation hydrolysis, creating a strongly acidic environment in which metals such as magnesium and zinc dissolve: Al3+ + H2O = AlOH2+ + H+ AlF3 fluoride
and AlPO4 orthophosphate are insoluble in water, and salts of very weak acids, for example H2CO3, are not formed at all by precipitation from an aqueous solution.
Double aluminum salts are known - alum of the composition MAl(SO4)2*12H2O (M=Na+, K+, Rb+, Cs+, TI+, NH4+), the most common of them is potassium alum KAl(SO4)2*12H2O.
The dissolution of amphoteric hydroxides in alkaline solutions is considered as a process of formation of hydroxo salts (hydroxo complexes).
The existence of hydroxocomplexes [Al(OH)4(H2O)2] -, [Al(OH)6]3-, [Al(OH)5(H2O)]2-;
of these, the first is the most durable. The coordination number of aluminum in these complexes is 6, i.e. aluminum is six-coordinated. Binary aluminum compounds Compounds with predominantly covalent bonds, for example Al2S3 sulfide and Al4C3 carbide, are completely decomposed by water:
Al2S3 + 6H2O = 2Al(OH)3 + 3H2S Al4C3 + 12H2O = 4Al(OH)3 + 3CH4
Application:
Widely used as a construction material. The main advantages of aluminum in this quality are lightness, malleability for stamping, corrosion resistance, and high thermal conductivity. Aluminum is an important component of many alloys (copper - aluminum bronze, magnesium, etc.) It is used in electrical engineering for the manufacture of wires and their shielding.
Aluminum is widely used in thermal equipment and cryogenic technology. Its high reflectivity, combined with low cost and ease of deposition, makes aluminum an ideal material for the manufacture of mirrors. Aluminum and its compounds are used in rocket technology as rocket fuel.
In the production of building materials as a gas-forming agent.
Allayarov Damir
HF Tyumen State University, 561 group.
Source: http://www.kontren.narod.ru/x_el/info13.htm
What was the first product made from aluminum?
April 25, 2017 at 4:01 pm
Life.ru talks about where else aluminum can be used.
In the sky and in space
Aluminum first “flyed” in 1900 - in the form of the frame and propellers of Ferdinand Zeppelin’s huge LZ-1 airship. But the soft, pure metal was only suitable for slow lighter-than-air aircraft.
Truly “winged” aluminum was already five times stronger, since it contained manganese, copper, magnesium, zinc in different percentages - the sky and space were conquered by varieties of duralumin, an alloy invented at the beginning of the twentieth century by the German engineer Alfred Wilm .
The material was promising, but it also had many limitations - it required so-called aging, that is, it did not gain the strength inherent in it immediately, but only over time. Yes, and it could not be welded. And yet, the conquest of space began precisely with duralumin, from which the ball of the famous first artificial Earth satellite was also made.
Much later, at the height of the space age, aluminum-based alloys and materials with much more remarkable properties began to appear.
For example, the friendship between aluminum and lithium has made it possible to make aircraft and rocket parts much lighter without reducing strength, and alloys with titanium and nickel have the property of “cryogenic hardening”: in the cold of space, their ductility and strength only increase.
The skin of the Buran space shuttle was made from a tandem of aluminum and scandium: aluminum-magnesium plates became much more tensile strength, while maintaining flexibility and doubling the melting point.
More modern materials are not alloys, but composites. But even in them the base is most often aluminum.
One of the modern and promising aerospace materials is called “boron-aluminum composite,” where boron fibers are sandwiched with layers of aluminum foil, forming an extremely strong and lightweight material under high pressures and temperatures. For example, the turbine blades of advanced aircraft engines are boron-aluminum load-bearing rods covered in a titanium “jacket.”
In the automotive industry and transport
Today, new Range Rover and Jaguar models feature 81% aluminum in their body structure. The first experiments with aluminum bodies are usually attributed to Audi, which presented the A8 made of light alloys in 1994.
However, back in the early twentieth century, this light metal on a wooden frame was the signature body style of the famous British sports cars Morgan.
The real “aluminum invasion” into the auto industry began in the 1970s, when factories began to massively use this metal for engine cylinder blocks and gearbox housings instead of the usual cast iron; a little later, light alloy wheels became widespread instead of stamped steel ones.
These days, the key trend in the auto industry is electricity. And light alloys based on aluminum are becoming particularly relevant in bodybuilding: the “energy-saving” metal makes the electric vehicle lighter, which means it increases the mileage on a single battery charge. Aluminum bodies are used by the Tesla brand, a trendsetter in the car market of the future, and that, in fact, says it all!
There are no domestic cars with aluminum bodies yet. But stainless and lightweight material is already beginning to penetrate the Russian transport sector. A typical example is the ultra-modern Vityaz-M high-speed trams, whose interiors are entirely made of aluminum alloys, which are practically eternal and do not require constant touch-up. It is worth noting that the creation of one tram interior requires up to 1.7 tons of aluminum, which is supplied by the Krasnoyarsk aluminum smelter Rusala.
“The ceiling, walls, racks are all aluminum.
And this is not just sheathing with sheets, the details are complex, combining finishing and load-bearing elements, and tunnels for ventilation and wiring,” says Vitaly Dengaev, general director of the Krasnoyarsk Machine-Building Components company, where the aluminum interiors of the Vityaz were created. “Plus, in addition to aesthetics, we also get the highest safety: unlike plastics and synthetics, the aluminum interior does not emit harmful substances if a fire occurs!”
On March 17 of this year, 13 Vityaz-M trams began running around Moscow and by April 5 they had already transported the first hundred thousand passengers! This fast and silent city transport with cabins for 260 people, with Wi-Fi, climate control, places for disabled people and strollers and other comfort elements, is designed for a service life of 30 years, which is twice as long as previous models. In the next three years, the capital will receive 300 Vityaz, 100 of which will be on the rails this season.
In the printers of the future
Elementary amateur 3D printers printing from plastic filament will no longer surprise anyone. Today begins the era of full-fledged serial 3D printing of metal parts.
Aluminum powder is perhaps the most common material for a technology called AF (from Additive Fabrication).
Additive in English is “additive”, and this is the deep meaning of the name of the technology: the part is not produced from a blank, from which excess material is cut off during processing, but, on the contrary, by adding material to the working area of the tool.
The metal powder comes out of the AF machine's dispenser and is laser sintered layer by layer into a single, strong mass of monolithic aluminum.
Parts that are made integral using the AF method amaze the imagination with their spatial complexity; It is impossible to perform them using classical methods even on the most modern metalworking machines! Due to the openwork design, parts created on additive printing machines from aluminum alloy powders have the strength of a monolith, while being several times lighter. They are produced without waste and quickly - such metal “laces” are indispensable in biomedicine, aviation and astronautics, precision mechanics, in the manufacture of molds, and so on.
Until recently, all technologies related to Additive Fabrication were foreign. But now domestic analogues are actively developing. For example, at the Ural Federal University (Ural Federal University) an experimental installation for the production of metal powders for AF-3D printing is being prepared. The installation operates on the principle of spraying molten aluminum with a jet of inert gas; this method will make it possible to obtain metal powders with any specified grain size parameters.
In construction and lighting
Aluminum can also be a facade and roofing material, the service life of which is not limited to a couple of years and which is extremely convenient for designers and installers! Special patented alloys and composites with a variety of properties have been developed for construction - Alclad, Kal-Alloy, Kalzip, Dwall Iridium. Aluminum can be used to stamp parts in which the roof plane is integral with the load-bearing elements. This is necessary, for example, to create retractable stadium roofs.
Which spacers are better: polyurethane or aluminum?
Coated with a special type of fluoropolymer, related to Teflon, aluminum roof parts can withstand enormous loads from wind and precipitation. And when constructing roofs of enormous size, where the total length of the sheet from edge to edge can reach several tens of meters, a special technology is used, the development of which was also made possible by the plasticity of aluminum.
To avoid the unreliable connection of many small sheets, aluminum tape several meters wide, rolled into a huge roll, is brought to the construction site, and right on the construction site it is passed through a special machine, which makes the even tape profiled, and therefore rigid. The aluminum profile is fed onto the roof of the building along special guides with rollers.
This technology was developed by the British Corus Group, one of the world leaders in the production of aluminum roofing sheets (now part of Tata Steel).
In our country, aluminum architecture is truly unfolding only now, lagging behind world rates, but vigorously catching up with them - recent examples of implementation include the roof of the Zenit Arena stadium in St. Petersburg, the facilities of the Kazan Universiade, the Sochi airport, a unique light-alloy bridge currently under construction in Nizhny Novgorod and other objects.
The building has been built, the roof has been erected, now we need light! And here aluminum is back in trend. It is not only a “winged” metal, but also a “metal of light”. There are now billions of LED lamps burning in the world and their number is growing every second. Each lamp has an aluminum heatsink that removes excess heat from the LED crystals, preventing them from overheating. But aluminum plays a much more important role in the manufacture of the base of the LEDs themselves - leucosapphire.
The Aluminum Association is convinced that within 2-3 years our enterprises will be able to completely replace imports of highly pure aluminum oxide into Russia, which will sharply stimulate domestic LED production.
Everywhere in our lives
We just don't always know about it! Almost all high-quality gadgets are made on the basis of aluminum alloys: frames and covers of smartphones, tablets, laptops, power bank cases and much more. Sports equipment, baby strollers, cooking utensils, radiators, furniture fittings - the list of areas where light metal is used is endless.
But why don't we always know about this? The fact is that aluminum and its alloys in “naked form”, like that well-known but hopelessly outdated aluminum spoon, are almost never found these days. Today the ball is ruled by anodizing technology, which allows parts made of aluminum and its alloys to be coated with a durable, wear-resistant oxide film.
Anodizing does not stain your hands and can achieve almost any color and texture.
One of the most promising household aluminum areas is bicycle frames. The aluminum frame is very light, making it very comfortable to lift the bike and ride it. The frame does not rust if the paint is damaged, alloying additives make the metal very strong, and technologies called “butting” and “hydroforming” make it possible to produce pipes of variable thickness and with any bends, lightening and strengthening the frame exactly where it is needed.
Millions of bikes - a huge market! However, for now, the frames of all two-wheelers sold and assembled in our country are imported. “However, a small revolution has emerged in this area: Rusal engineers have developed a special new alloy, ideal for bicycle frames, and are working to develop the production of frames in our country,” says Deputy editor of the Metal Supply and Sales magazine Leonid Khazanov. — The project is supported by Rusal, as the only Russian aluminum producer, the Tatprof aluminum profile plant located in Naberezhnye Chelny, which is ready to make pipes for frames, and the domestic company, the bicycle assembler Velomotors. If the planned scale of production is realized, our frames should become cheaper than Chinese ones and at the same time much higher in quality.”
Russia is the world leader in aluminum, one of the top three producers of this metal. The USSR began building aluminum smelters in the early thirties of the 20th century, completely getting rid of imports by the middle of the decade. However, strangely enough, we are truly entering the “aluminum era” only now.
The main owner of Rusal, Oleg Deripaska, has repeatedly stated that the level of aluminum consumption in Russia is much lower than the global average, and today it is finally time to break this trend and make maximum efforts and resources to create processing capacities in the country and displace imported products, the quality of which is often compromised a lot of questions.
For many years, design engineers avoided the use of aluminum, since aluminum alloys and composites simply did not appear in outdated regulatory documents - today, standards, GOSTs and SNIPs are revised and updated in the spirit of the times. And almost all areas of industry are waiting to discover new areas of use of this metal.
Source: http://ooo-asteko.ru/chto-bylo-pervym-izdeliem-sdelannym-iz-alyuminiya/
Aluminum metallurgy. How is high purity aluminum obtained? — PCC Group Product Portal
This metal has been well known for more than 2 thousand years and is characterized by wide technical applications. What can it be used for?
In industry, aluminum is mainly used in alloys with other elements, which improves its performance properties. As such, it is a versatile construction material with very versatile applications.
Among aluminum alloys, we can distinguish, in particular, casting alloys and alloys used for plastic processing. In addition to aluminum, they contain elements such as copper, magnesium, silicon and manganese.
Aluminum alloys are used, in particular, in aviation, the chemical industry, automotive industry and even shipbuilding.
Aluminum is widely used in industry in its pure form for the manufacture of various household items, such as, for example, mirrors, cans for drinks and food, kitchen utensils or the well-known aluminum foil.
It is also used for the manufacture of chemical equipment, electrical wires, and even explosives. To isolate this element from bauxite ore, it is necessary to carry out two successive stages. The first of these is the Bayer process, which produces aluminum oxide from the mineral.
This compound is then subjected to electrolysis, resulting in the formation of commercial grade aluminum.
What is aluminum made from?
Pure aluminum does not occur in nature due to its ability to passivate. This phenomenon involves the oxidation of metal in the presence of air, resulting in the formation of a passive protective layer on its surface. Aluminum is coated with a layer of aluminum oxide (Al2O3) up to several nm thick. Then, under the influence of moisture, the outer layer undergoes partial hydrolysis, as a result of which hydroxide is additionally formed, i.e. Al(OH)3.
Aluminum is part of various mineral rocks found in nature in the form of ores. To produce pure aluminum, clayey bauxite ore is used primarily. It is formed mainly in places where aluminosilicate rocks are weathered in hot climates and also contains iron compounds. This is a rock with a characteristic red or brown color, which is found in two types: silicate and carbonate.
Production of technical purity aluminum
Aluminum of technical purity (more than 99%) is industrially produced as a result of two sequential processes. As a result of the first, aluminum oxide is obtained (Bayer process), and at the next stage, an electrolytic reduction process is carried out (Electrolysis by the Hall-Heroult method), due to which pure aluminum is obtained. To reduce the costs associated with transporting bauxite ore, most processing plants are built close to the mines.
Bayer process
The first step after mining the ore is to wash it with water. This removes most of the contaminants that simply dissolve in water. Then, CaO is added to the water-treated raw material, i.e. calcium oxide.
After this, it is crushed using special tube mills until grains with a very small diameter are obtained, i.e. less than 300 microns.
Proper grinding of the raw material is extremely important as it provides a large surface area of the grains, which in turn affects the efficiency of the extraction process.
The next step in the production of aluminum oxide is to dissolve the grains using an aqueous solution of caustic soda. In the PCC Group, sodium hydroxide is produced using membrane electrolysis.
The product thus obtained is characterized by very high quality and purity, while meeting the requirements of the latest edition of the European Pharmacopoeia. The mixture containing ground grains and sodium hydroxide is stored for several hours in special reactors called autoclaves.
During the ongoing deposition process, the reactors are maintained at high pressure and elevated temperature. In this way, sodium aluminate is obtained, which is then purified using various filters.
In the next step, the purified sodium aluminate solution undergoes decomposition. As a result, soda lye (i.e. an aqueous solution of caustic soda) and aluminum hydroxide crystals of high purity are formed. The precipitate obtained as a result of crystallization is filtered off and washed with water. And the remaining soda liquor is heated and returned to the process for reuse.
The final step in the production of pure alumina is calcination. It consists of heating aluminum hydroxide at temperatures above 1000oC, resulting in its decomposition into Al2O3, which is obtained in the form of a pure white powder. Thus prepared aluminum oxide is transported to furnaces to obtain aluminum metal through the process of electrolytic reduction.
Aluminum oxide electrolysis
The next step in obtaining pure aluminum is to carry out the electrolysis process using the Hall-Heroult method. First of all, the Al2O3 obtained in the Bayer process is melted with cryolite and the thus prepared solution is subjected to an electrolysis process at a temperature not exceeding 900oC.
The liquid aluminum thus obtained is separated from the electrolyte and removed from the electrolytic baths using the so-called. vacuum siphons. Then the raw material enters the foundry, from where at a further stage it is put into hot furnaces, in which the processing process takes place.
It involves cleaning aluminum to achieve maximum purity. In industrial conditions, aluminum can be cleaned using two methods. The first involves melting aluminum and passing chlorine through it, causing impurities to bind with the chlorine to form chlorides, which are then removed from the process.
The second method is the electrolytic reduction of aluminum molten with copper. The final product thus obtained is characterized by very high purity.
Aluminum – the material of the future
The development of a method for producing pure aluminum from bauxite using the Bayer process and Hall-Heroult electrolysis expanded the range of applications of this element. In addition, the combination of high strength with lightness has made it possible in some cases to replace more expensive steel with aluminum.
Resistance to atmospheric factors has made it possible to use aluminum in the production of window and door profiles.
Another benefit of aluminum is that it can be recycled many times over, making it a relatively environmentally friendly material.
To summarize, aluminum is a versatile material widely used in the food, energy, chemical, transportation, construction, automotive and aviation industries. Considering its many benefits, this is certainly not the end of its applications and it will continue to gain popularity in the near future.
Source: https://www.products.pcc.eu/ru/blog/%D0%BC%D0%B5%D1%82%D0%B0%D0%BB%D0%BB%D1%83%D1%80 %D0%B3%D0%B8%D1%8F-%D0%B0%D0%BB%D1%8E%D0%BC%D0%B8%D0%BD%D0%B8%D1%8F-%D0%BA %D0%B0%D0%BA-%D0%BF%D0%BE%D0%BB%D1%83%D1%87%D0%B0%D1%8E%D1%82-%D0%B0%D0%BB /
Aluminum: characteristics, properties, production. Chemistry notes – TeacherPRO
Key words of the abstract: aluminum, properties of aluminum, production and use of aluminum, aluminosilicates, clay, aluminum oxide, bauxite, duralumin, duralumin.
Aluminum Al – element No. 13, 3rd period, IIIA group, Ar (Al) = 27. Electronic configuration of an unexcited aluminum atom 1s22s22p6 3s23p1 :
Aluminum is a p-element . In its compounds it always has an oxidation state of +3. Aluminum oxide and hydroxide (Al2O3 and Al(OH)3, respectively) are amphoteric. There is a hydrogen compound of aluminum - aluminum hydride AlH3 (alane) - a white powder.
In terms of prevalence in the earth's crust, aluminum ranks 4th (after O, Si, H). The bulk of aluminum is concentrated in aluminosilicates. The product of the destruction of aluminosilicates is clay , it consists of kaolinite - Al2O3 • 2SiO2 • 2H2O. Typically, clay contains an admixture of iron compounds, which gives it a brown color. Of the other minerals, bauxite is the most common - Al2O3 • nH2O.
ALUMINUM IS A SIMPLE SUBSTANCE
Aluminum is a silvery-white metal (in air it becomes covered with a dense thin film of oxide), density 2.7 g/cm3 (light metal), low-melting temperature (melt point = 660 °C).
In air, aluminum is covered with a durable, thin (10–8 m) protective film of oxide, which prevents the penetration of oxygen into the metal and almost completely stops further oxidation.
Aluminum powder burns when heated in oxygen :
When aluminum oxidizes, a large amount of heat is released. When heated aluminum powder enters an oxygen atmosphere, it reacts with the release of a huge amount of heat, reaching temperatures of up to 3000–3500 °C. The thermal effect of the reaction of aluminum with oxygen is extremely high; the formation of this compound is energetically very favorable.
When heated, aluminum easily reacts with sulfur :
Aluminum powder easily reacts with halogens and burns in a chlorine atmosphere. A piece of aluminum from which the oxide film has been removed reacts violently with bromine. These reactions occur without heating:
Aluminum powder reacts with crystalline iodine, and in the presence of a catalyst (or upon heating), droplets of water are released.
Aluminum without an oxide film reacts with nitrogen under strong heating (800–1200 °C), forming aluminum nitride:
When heated strongly (1500–1700 °C), aluminum reacts with carbon (graphite) to form aluminum carbide:
Aluminum does not react directly with hydrogen . Aluminum hydride is obtained indirectly.
Aluminum interacts vigorously with water if the protective effect of the oxide film is removed mechanically or by amalgamation:
Due to the high thermal effect of combining aluminum with oxygen, aluminum actively reduces many metals from oxides ( aluminothermy ):
In this case, the reaction is usually accompanied by the release of a large amount of heat and an increase in temperature to 1200–3000 °C. Aluminothermy is used in the production of manganese, chromium, vanadium, tungsten, and ferroalloys.
As a method for producing metals, aluminothermy was proposed by N. Beketov in 1859. It is used to produce many metals (Mn, Cr, V, W, Sr, Ba, etc.).
Aluminum reacts with hydrohalic acids , dilute sulfuric and nitric acids to form salts in which aluminum is in cationic form and liberate hydrogen. For example:
Aluminum does not react with concentrated nitric and sulfuric acids under normal conditions. A protective oxide film is formed on the surface of the aluminum, and the aluminum is passivated. Aluminum reacts with dilute nitric acid (2–3 mol/l) to form aluminum nitrate, ammonium nitrate and water:
Aluminum actively interacts with alkali solutions . Alkalis dissolve the oxide film on the surface of aluminum. Salts are formed in which aluminum is in anionic form, and hydrogen is released:
Aluminum reacts with salt solutions , reducing cations of less active metals (metals located in the voltage series to the right of aluminum):
PRODUCTION AND APPLICATION OF ALUMINUM
The main raw material for aluminum production is bauxite containing 32–60% alumina Al2O3. Aluminum is produced by electrolysis of molten alumina Al2O3 in molten cryolite Na3AlF6. The electrolyzer contains 6–8% alumina and 92–94% cryolite. Cryolite is not consumed during electrolysis. It is obtained artificially - by the interaction of Al(OH)3, HF and Na2CO3.
Aluminum reduction occurs at the cathode: Al3+ + 3е– → Al 0,
at the anode – oxidation of its oxide: 2Al2О 3 – 12е– → 4Al3+ + 3O2,
and then the secondary reaction at the anode: C + O2 → CO2 or 2 C + O2 → 2 CO
In terms of breadth of application , aluminum alloys occupy second place after cast iron and steel. Aluminum is the basis of light alloys (for example, duralumin, silumin); it is used for the production of various containers and devices, foil and wire, as a steel deoxidizer and a reducing agent in aluminothermy.
High electrical conductivity and corrosion resistance make it possible to use aluminum for the manufacture of electrical wires, cables, and capacitors.
The lightness, corrosion resistance of aluminum and the relative non-toxicity of its compounds make it possible to use aluminum for the manufacture of household utensils, and aluminum foil in the food and pharmaceutical industries for packaging products and drugs.
Of the aluminum alloys, the most common is duralumin, abbreviated as duralumin. Additions of copper, manganese, etc. give duralumin greater hardness compared to pure aluminum. Duralumin is the main structural material in aircraft construction. Aluminum alloys are widely used in the automotive industry, shipbuilding, and aviation technology.
Chemistry lesson summary “Aluminum: characteristics and properties.” Select next action:
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Composition and structure of aluminum
Aluminum is the most common metal in the earth's crust. It is classified as a light metal. It has low density and mass. In addition, it has a fairly low melting point. At the same time, it has high ductility and shows good thermal and electrical conductivity characteristics.
Aluminum crystal latticeAluminum structure
The tensile strength of pure aluminum is only 90 MPa. But, if you add some substances to the melt, for example, copper and a number of others, then the tensile strength increases sharply to 700 MPa. The same result can be achieved using heat treatment.
Aluminum, which has extremely high purity - 99.99%, is produced for use in laboratory purposes. For industrial applications, commercially pure aluminum is used. When producing aluminum alloys, additives such as iron and silicon are used. They do not dissolve in the aluminum melt, and the additive reduces the ductility of the base material, but at the same time increases its strength.
Appearance of a simple substance
The structure of this metal consists of simple cells consisting of four atoms. This structure is called face-centric.
Calculations show that the density of pure metal is 2.7 kg per cubic meter.
Properties and characteristics
Aluminum is a metal with a silvery-white surface. As already noted, its density is 2.7 kg/m3. The temperature is 660°C.
Its electrical conductivity is equal to 65% of copper and its alloys. Aluminum and most of its alloys are resistant to corrosion. This is due to the fact that an oxide film forms on its surface, which protects the base material from exposure to atmospheric air.
In the untreated state, its strength is 60 MPa, but after adding certain additives it increases to 700 MPa. The hardness in this state reaches 250 HB.
Aluminum can be easily processed under pressure. To remove work hardening and restore ductility after processing, aluminum parts are annealed, and the temperature should be within 350°C.
The production of aluminum melt, like many other materials, occurs after thermal energy has been supplied to the original metal. It can be supplied either directly into it or from outside.
The melting point of aluminum directly depends on the level of its purity:
-
- Ultra-pure aluminum melts at a temperature of 660.3°C.
- With an aluminum content of 99.5%, the melting point is 657°C.
- With a content of this metal of 99%, the melt can be obtained at 643°C.
Aluminum meltAluminum production process
An aluminum alloy can contain various substances, including alloying ones. Their presence leads to a decrease in the melting point. For example, if there is a large amount of silicon, the temperature can drop to 500°C. In fact, the concept of melting point applies to pure metals. Alloys do not have any constant melting point. This process occurs within a certain heating range.
In materials science there is a concept - solidus and liquidus temperatures.
The first temperature indicates the point at which the melting of aluminum begins, and the second shows at what temperature the alloy will finally melt. In the interval between them, the alloy will be in a mushy state.
Decrease temperature
Before you start melting metal, you can perform certain operations that will reduce the melting temperature. For example, sometimes aluminum powder is melted. In a powdered state, the metal begins to melt somewhat faster.
But with such processing, there is a real danger that when interacting with oxygen contained in the atmosphere, aluminum powder will begin to oxidize with a large release of heat and the formation of metal oxides; this process occurs at a temperature of 2300 degrees.
The main thing is to prevent contact between the melt and water at this moment of melting. This will cause an explosion.
The relatively low melting point of aluminum allows this operation to be carried out at home. It should be noted right away that using a powdered mixture as a raw material in a home workshop is too dangerous. Therefore, either ingots or cut wire are used as raw materials. If there are no special quality requirements for the future product, then anything made from this metal can be used for melting.
Melting aluminum in a homemade forge
In this case, it is not particularly important whether the raw materials are coated with paint or not. When aluminum melts, all foreign substances will simply burn out and be removed along with the slag.
To obtain a high-quality melting result, it is necessary to use materials called fluxes. They are designed to solve the problem of binding and removing foreign impurities and contaminants from the melt.
A home craftsman who decides to melt aluminum at home should be aware that this is a rather dangerous process. And therefore it is impossible to do without the use of protective equipment. In particular, gloves, an apron, and goggles should be used. The fact is that the melt temperature is within 600 degrees. Therefore, it makes sense to use the protective equipment that welders use.
Using protective equipment when melting aluminum
By the way, when melting aluminum and using cleaning chemicals, it is necessary to protect the respiratory system from combustion products.
Selecting a mold for casting
When choosing a mold for casting aluminum, a home craftsman must understand for what purpose he is processing aluminum. If the future casting is intended for use as solder, then there is no need to use any special forms. To do this, you can use a metal sheet on which to cool the molten metal.
But if there is a need to obtain even a simple part, then the master must decide on the type of mold for casting.
The mold can be made from plaster. To do this, gypsum in a liquid state is poured into an oil-treated mold. After it begins to harden, a casting model is installed into it. In order for molten metal to be poured into the mold, a sprue must be formed.
To do this, a cylindrical part is placed in the mold. Forms can be detachable or not. The process of making a split mold is complicated by the fact that the model will be in two halves. After hardening, they are separated, the model is removed and connected again. The form is ready to use.
Aluminum casting die
To obtain high-quality castings, it is advisable to use metal molds (moulds), but it is advisable to produce them only in factory conditions.
Source: https://stankiexpert.ru/spravochnik/materialovedenie/alyuminiy.html
History of aluminum. Description
Aluminum is the most famous and ancient metal. In the form of various clay compounds, it has been known to mankind since time immemorial. Ancient historians testified that “lumen” (translated from Latin as alum) or aluminum-potassium sulfate was used in a variety of fields: both as a mordant for dyeing fabrics and as a fire retardant, and was also used for the manufacture of various household products and decorations
History of production and use of aluminum
In the mid-19th century in Western Europe, scientists desperately tried to obtain aluminum in its pure form. In 1825, Danish explorer H.C. Oersted was the first to carry out a similar experiment using potassium in the form of an amalgam. Unfortunately, it was not possible to accurately determine the resulting substance.
However, two years later, the German scientist Wöhler became interested in obtaining aluminum. He used pure potassium to restore the metal. After 20 years of persistent searching, he managed to obtain pure aluminum in the form of granules the size of a match head. Aluminum turned out to be a beautiful and light metal, similar to silver. These properties of aluminum determined its high cost at that period of history: it was valued more expensive than gold.
At the 1855 Paris Exhibition, aluminum was the main attraction. Aluminum jewelry was placed next to the French crown diamonds. Aluminum has become a very fashionable metal. It was considered a noble element created by nature to create masterpieces of art.
Since the physical and chemical properties of aluminum were poorly studied, jewelers independently invented ways to process it. The softness and pliability of the metal allowed them to create products of any shape, make imprints of intricate patterns, and apply a variety of designs. Aluminum was coated with gold, polished, matted.
However, over time, aluminum began to go out of fashion. In the mid-1860s, a kilogram of this metal already cost only about one hundred old francs, compared to 3 thousand in 1854-1856.
Currently, the first aluminum products are of great value. Unfortunately, fashion fans have replaced most of them with gold, silver and other precious alloys and metals.
However, scientists were not stopped by changing fashion. In 1886, chemist Charles Martin Hall developed a cheap method for producing aluminum in large quantities. He added and dissolved a small amount of aluminum oxide in molten cryolite (a compound of aluminum with sodium and fluorine). Then, placing the mixture in a granite vessel, he passed an electric current through it.
After several hours of waiting, he saw shiny “buttons” of pure aluminum at the bottom of the vessel. The Austrian engineer Karl Joseph Bayer, who was working in Russia at that time, did not stand aside and proposed a technology for producing alumina, which helped make the new method even cheaper.
As a result, Bayer and Hall's version of aluminum production is still used in modern manufacturing today.
Improving the properties of aluminum
The new material, which could now be used in industry, was good for everyone. However, it has been noted that pure aluminum is not strong enough for some applications.
The German chemist Alfred Wilm joined the fight against this problem by alloying it with small amounts of magnesium, copper and manganese. The resulting alloy was so strong that in 1911, a batch of material was produced in the town of Durene, named duralumin in its honor. A little later, in 1919, the first aircraft was made from it. Thus aluminum triumphantly conquered the whole world.
Currently, it is difficult to name an industry that can do without this light silver metal.
Aluminum, which ranks third in concentration in the earth's crust after oxygen and silicon, is attracting the attention of specialists with renewed vigor as the metal of the future.
The combination of its advantages, such as low density, high thermal and electrical conductivity, strength characteristics, as well as high corrosion resistance and manufacturability, make aluminum one of the most valuable materials on the planet.
Source: https://oxi-pro.ru/istoriya-polucheniya-i-primeneniya-alyuminiya
Aluminum - general characteristics of the element, chemical properties
Aluminum is an element of the main subgroup of group III, third period, with atomic number 13. Aluminum is a p-element. The outer energy level of the aluminum atom contains 3 electrons, which have the electronic configuration 3s23p1 . Aluminum exhibits an oxidation state of +3.
Belongs to the group of light metals. The most common metal and the third most abundant chemical element in the earth's crust (after oxygen and silicon).
The simple substance aluminum is a light, 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.
1. Aluminum easily reacts with simple non-metallic substances:
4Al + 3O2 = 2Al2O3
2Al + 3Cl2 = 2AlCl3,
2Al + 3 Br2 = 2AlBr3
2Al + N2 = 2AlN
2Al + 3S = Al2S3
4Al + 3C = Al4C3
Aluminum sulfide and carbide are completely hydrolyzed:
Al2S3 + 6H2O = 2Al(OH)3 + 3H2S
Al4C3 + 12H2O = 4Al(OH)3+ 3CH4
2. Aluminum reacts with water
(after removing the protective oxide film):
2Al + 6H2O = 2Al(OH)3 + 3H2
3. Aluminum reacts with alkalis
2Al + 2NaOH + 6H2O = 2Na[Al(OH)4] + 3H2
2(NaOH•H2O) + 2Al = 2NaAlO2 + 3H2
First, the protective oxide film dissolves: Al2O3 + 2NaOH + 3H2O = 2Na[Al(OH)4].
Then the reactions occur: 2Al + 6H2O = 2Al(OH)3 + 3H2, NaOH + Al(OH)3 = Na[Al(OH)4],
or in total: 2Al + 6H2O + 2NaOH = Na[Al(OH)4] + 3H2,
and as a result, aluminates are formed: Na[Al(OH)4] - sodium tetrahydroxoaluminate Since the aluminum atom in these compounds is characterized by a coordination number of 6, not 4, the actual formula of tetrahydroxy compounds is as follows: Na[Al(OH)4(H2O) 2]
4. Aluminum is easily dissolved in hydrochloric and dilute sulfuric acids:
2Al + 6HCl = 2AlCl3 + 3H2
2Al + 3H2SO4(dil) = Al2(SO4)3 + 3H2
When heated, it dissolves in acids - oxidizing agents that form soluble aluminum salts:
8Al + 15H2SO4(conc) = 4Al2(SO4)3 + 3H2S + 12H2O
Al + 6HNO3(conc) = Al(NO3)3 + 3NO2 + 3H2O
5. Aluminum reduces metals from their oxides (aluminothermy):
8Al + 3Fe3O4 = 4Al2O3 + 9Fe
2Al + Cr2O3 = Al2O3 + 2Cr
Source: http://himege.ru/alyuminij-xarakteristika-elementa/
