How to extract aluminum

Aluminum, aluminum production: technology, process and description

Aluminum has many properties that make it one of the most used materials in the world. It is widespread in nature, occupying first place among metals. It would seem that there should be no difficulties with its production. But the high chemical activity of the metal means that it cannot be found in its pure form, and its production is difficult, energy-intensive and costly.

Raw materials for production

What raw materials is aluminum obtained from? Producing aluminum from all the minerals that contain it is expensive and unprofitable. It is mined from bauxite, which contains up to 50% aluminum oxides and lies directly on the surface of the earth in significant masses.

These aluminum ores have a rather complex chemical composition. They contain aluminas in an amount of 30-70% of the total mass, silicas, which can be up to 20%, iron oxide in the range from 2 to 50%, titanium (up to 10%).

Alumina, and this is aluminum oxide, consists of hydroxides, corundum and kaolinite.

Recently, aluminum oxides began to be obtained from nephelines, which also contain oxides of sodium, potassium, silicon, and alunites.

To produce 1 ton of pure aluminum, about two tons of alumina are needed, which, in turn, is obtained from about 4.5 tons of bauxite.

The world's bauxite reserves are limited. There are only seven areas around the globe with its rich deposits. These are Guinea in Africa, Brazil, Venezuela and Suriname in South America, Jamaica in the Caribbean, Australia, India, China, Greece and Turkey in the Mediterranean and Russia.

In countries where there are rich bauxite deposits, aluminum production can also be developed. Russia mines bauxite in the Urals, in the Altai and Krasnoyarsk territories, in one of the regions of the Leningrad region, and nepheline on the Kola Peninsula.

The richest deposits belong to the Russian united company UC RUSAL. It is followed by the giants Rio Tinto (England-Australia), which has teamed up with the Canadian Alcan and CVRD. In fourth place is the Chalco company from China, then the American-Australian corporation Alcoa, which are also large aluminum producers.

Origin of production

Danish physicist Oersted was the first to isolate aluminum in its free form in 1825. The chemical reaction took place with aluminum chloride and potassium amalgam, instead of which two years later the German chemist Wöhler used potassium metal.

Potassium is a fairly expensive material, so in the industrial production of aluminum, the Frenchman Sainte-Clair Deville instead of potassium in 1854 used sodium, a much cheaper element, and stable double chloride of aluminum and sodium.

Russian scientist N. N. Beketov was able to displace aluminum from molten cryolite with magnesium. At the end of the eighties of the same century, the Germans used this chemical reaction at the first aluminum plant. In the second half of the 18th century, about 20 tons of pure metal were obtained by chemical methods. It was very expensive aluminum.

The production of aluminum using electrolysis originated in 1886, when almost identical patent applications were simultaneously filed by the founders of this method, the American scientist Hall and the Frenchman Héroux. They proposed dissolving alumina in molten cryolite and then producing aluminum by electrolysis.

This is where the aluminum industry began, which over more than a century of history has become one of the largest branches of metallurgy.

Main stages of production technology

In general terms, aluminum production technology has not changed since its inception.

The process consists of three stages. The first of the aluminum ores, be it bauxite or nepheline, produces alumina - aluminum oxide Al2O3.

Then industrial aluminum is separated from the oxide with a purity of 99.5%, which is not enough for some purposes.

Therefore, aluminum is refined at the last stage. Aluminum production ends with its purification to 99.99%.

Alumina production

There are three ways to obtain aluminum oxide from ores:

- acidic;

— electrolytic;

- alkaline.

The last method is the most common, developed back in the 18th century, but since then repeatedly refined and significantly improved, and is used for processing high-grade bauxite. About 85% of aluminas are obtained this way.

The essence of the alkaline method is that aluminum solutions decompose at high speed when aluminum hydroxide is introduced into them. The solution remaining after the reaction is evaporated at a high temperature of about 170 ° C and again used to dissolve the alumina;

First, bauxite is crushed and ground in mills with caustic alkali and lime, then in autoclaves at temperatures up to 250 ° C, its chemical decomposition occurs and sodium aluminate is formed, which is diluted with an alkaline solution at a lower temperature - only 100 ° C. The aluminate solution is washed in special thickeners, separated from sludge. Then it decomposes. The solution is pumped through filters into containers with mixers for constant mixing of the composition, to which solid aluminum hydroxide is added for seeding.

In hydrocyclones and vacuum filters, aluminum hydroxide is released, part of which is returned as a seed material, and part is used for calcination. The filtrate remaining after separation of the hydroxide is also returned to the circulation for leaching the next batch of bauxite.

The process of calcination (dehydration) of hydroxide in rotary kilns occurs at temperatures up to 1300° C.

To produce two tons of aluminum oxide, 8.4 kWh of electricity is consumed.

A strong chemical compound with a melting point of 2050° C is not yet aluminum. Aluminum production is ahead.

Electrolysis of aluminum oxide

The main equipment for electrolysis is a special bath lined with carbon blocks. An electric current is supplied to it. Carbon anodes are immersed in the bath, burning when pure oxygen is released from the oxide and forming carbon oxide and carbon dioxide. Baths, or electrolyzers, as experts call them, are connected in an electrical circuit in series, forming a series. The current strength is 150 thousand amperes.

Anodes can be of two types: fired from large coal blocks, the mass of which can be more than a ton, and self-burning, consisting of coal briquettes in an aluminum shell, which are sintered during the electrolysis process under high temperatures.

The operating voltage on the bath is usually about 5 volts. It takes into account both the voltage required for the decomposition of the oxide and the inevitable losses in the branched network.

From the aluminum oxide dissolved in the cryolite-based melt, the liquid metal, which is heavier than the electrolyte salts, settles on the carbon base of the bath. It is pumped out periodically.

The aluminum production process requires a lot of electricity. To obtain one ton of aluminum from alumina, you need to consume about 13.5 thousand kWh of DC electricity. Therefore, another condition for the creation of large production centers is a powerful power plant operating nearby.

Aluminum refining

The most famous method is three-layer electrolysis. It also takes place in electrolysis baths with coal beds lined with magnesite. The anode in the process is the molten metal itself, which is purified. It is located in the bottom layer on the conductive hearth. Pure aluminum, which is dissolved from the electrolyte in the anode layer, rises up and serves as the cathode. Current is supplied to it using a graphite electrode.

The electrolyte in the intermediate layer is aluminum fluorides, either pure or with the addition of sodium and barium chloride. It heats up to a temperature of 800°C.

Electricity consumption during three-layer refining is 20 kWh per kg of metal, that is, 20 thousand kWh is needed for one ton. That is why, like no other metal production, aluminum requires not just a source of electricity, but a large power plant in close proximity.

Refined aluminum contains iron, silicon, copper, zinc, titanium and magnesium in very small quantities.

After refining, aluminum is processed into commercial products. These include ingots, wire, sheets, and pigs.

The segregation products obtained as a result of refining, partly in the form of a solid sediment, are used for deoxidation, and partly are removed in the form of an alkaline solution.

Absolutely pure aluminum is obtained by subsequent zone melting of the metal in an inert gas or vacuum. Its notable characteristic is its high electrical conductivity at cryogenic temperatures.

Recycling of secondary raw materials

A quarter of the total demand for aluminum is met by recycling raw materials. Recycled products produce shaped castings.

Pre-sorted raw materials are melted in a threshold furnace. It retains metals that have a higher melting point than aluminum, such as nickel and iron. Various non-metallic inclusions are removed from molten aluminum by blowing with chlorine or nitrogen.

More fusible metal impurities are removed by adding magnesium, zinc or mercury and vacuuming. Magnesium is removed from the melt with chlorine.

A given casting alloy is obtained by introducing additives that are determined by the composition of molten aluminum.

Aluminum production centers

In terms of aluminum consumption, China ranks first, leaving the United States in second place and Germany, which ranks third, far behind.

China is also a country producing aluminum, leading in this area by a huge margin.

The top ten, in addition to China, includes Russia, Canada, UAE, India, USA, Australia, Norway, Brazil and Bahrain.

In Russia, the united company RUSAL has a monopoly in the production of alumina and aluminum. It produces up to 4 million tons of aluminum per year and exports products to seventy countries, and is present on five continents in seventeen countries.

The American company Alcoa owns two metallurgical plants in Russia.

The largest aluminum producer in China is Chalco. Unlike foreign competitors, all its assets are concentrated in its home country.

The Hydro Aluminum division of the Norwegian company Norsk Hydro owns aluminum smelters in Norway, Germany, Slovakia, Canada, and Australia.

Australian BHP Billiton owns aluminum production in Australia, South Africa and South America.

Alba (Aluminum Bahrain BSC) is located in Bahrain - perhaps the largest production. Aluminum from this manufacturer accounts for more than 2% of the total volume of “winged” metal produced in the world.

So, to summarize, we can say that the main aluminum producers are international companies that own bauxite reserves. And the extremely energy-intensive process itself consists of the production of alumina from aluminum ores, the production of fluoride salts, which include cryolite, carbon anode mass and carbon anode, cathode, lining materials, and the actual electrolytic production of pure metal, which is the main component of aluminum metallurgy.

Source: https://FB.ru/article/243799/alyuminiy-proizvodstvo-alyuminiya-tehnologiya-protsess-i-opisanie

Features of aluminum production: calculation of raw materials and production technology

Aluminum is a chemical element that occupies a leading position among the most abundant metals in the earth's crust, as well as the most commonly used. Its content in the ground is equal to 9%. It is found only in the form of compounds represented by aluminum oxide or alumina. It is clay that contains about 30% of this oxide.

This metal compares favorably with other types due to its properties. And this means excellent plasticity, high coefficients of thermal and electrical conductivity, and low density. This article will tell you about the technologies for the production and extraction of aluminum and its alloys in the world, as well as the important factors of such events.

In order to mine alumina in natural conditions and then extract aluminum from it, you will need a fairly large amount of equipment:

• Machines for distributing alumina;
• Cathode busbar;
• Dry gas cleaning installation;
• Electrolyzer;
• Cranes for installation, linear and technical purposes;
• Equipment necessary for foundry and anode assembly shops.

To produce aluminum, you need not only a large amount of equipment, but also a fairly large area, as well as a powerful electrical network.

The fact is that the electrolysis process takes place in special baths at a temperature of 9600C and a current of about 250,000 A.

To organize such a production process, a huge amount of electricity will be required, which is why large producers of this metal try to locate their workshops in close proximity to hydroelectric power plants that supply cheaper energy. The following is a discussion of raw materials for aluminum production.

The video below talks about aluminum production:

In order to obtain aluminum, it is necessary to load anode mass, alumina, and fluorine salt into the electrolyzer. During electrolysis, carbon oxides are produced from clay, as well as fluoride compounds in a gaseous state. In this case, part of the anode mass is consumed in the form of foam, which is removed from the surface of the electrolyte itself.

Excessive consumption of anode mass, as well as fluoride salts, may indicate poor quality of the mass itself, as well as improper maintenance of the equipment used.

In theory, to produce 1 kg of aluminum, 1.9 kg of alumina will be required. The rest of it includes all kinds of impurities and losses during the production process. However, in practice, much more raw materials may be required, depending on the type of clay, equipment used and other factors.

Next, the technology of casting and production of aluminum welding with argon is considered.

Aluminum production technologies

The aluminum production technology includes the following stages:

1. Extraction of alumina (aluminum oxide) from aluminum ores.
2. Isolation from aluminum oxide.
3. Complete cleaning of aluminum.

Alumina can be obtained using acid, alkaline and electrolytic methods. The first option is preferable to use when working with high grades of raw materials. The second method involves the rapid decomposition of the aluminum solution by introducing aluminum hydroxide. The solution formed after this reaction is evaporated for subsequent use for alumina.

The first stage of aluminum extraction is the careful crushing of bauxite using caustic alkali or lime. Then the raw material is placed in autoclaves, where at a temperature of 250°C it decomposes and sodium aluminate is released. The resulting sodium solution goes through a purification stage in special thickeners, where it is separated from the sludge. The purified solution is passed through filters and sent to containers with regular stirring.

In vacuum filters and cyclones, aluminum oxide is released, part of which is used for seeding, and the rest is sent for calcination. This process is also called dehydration and occurs at a temperature of about 1300°C. On average, to obtain 2 tons of oxide, energy up to 8.5 kW/h will be required. the resulting fairly strong connection is not yet pure aluminum.

This video will tell you about the electrolysis process in aluminum production:

The main equipment at this stage is a special bath (electrolyzer), equipped with carbon blocks. An electric current with a power of up to 150,000 A is supplied to it, and carbon anodes are loaded into the container itself, which burn after releasing pure oxygen and form carbon monoxide.

Anodes are divided into two types:

• Obtained by burning coal blocks, the mass of which can exceed 1 ton.
• Self-burning, including coal briquettes that are baked during electrolysis.

Metal refining

The most popular method for producing aluminum is three-layer electrolysis, which takes place in special baths lined with magnesite. The molten aluminum itself acts as the anode. It is in the lowest layer.

Pure metal, which dissolves in the anode layer due to the electrolyte process, rises to the surface acting as a cathode. Refined aluminum contains magnesium, titanium and other impurities in a minimal proportion. And already at this stage it receives the form of commercial products, be it ingots, pigs or wire.

Read below about Russia and other countries with aluminum mining and production plants.

The largest aluminum producer is the Rusal company, which produces more than 4 million tons of aluminum per year. The list of largest aluminum producers in Russia also includes:

• SUAL company, specializing in working with aluminum alloys;
• JSC "BAZ", operating in the production and extraction of alumina and aluminum hydroxide;
• VgAZ, a plant for the production of primary aluminum.

Aluminum production is a complex process that requires the necessary equipment, knowledge of technology, compliance with special conditions and labor costs. But the manufacture of various aluminum products is a popular business.

This video will tell you about the prospects for aluminum production:

Source: http://stroyres.net/metallicheskie/vidyi/tsvetnyie/alyuminiy/osobennosti-proizvodstva-i-dobyichi.html

Bauxite

Aluminum ore has gained the most popularity in modern industry. Aluminum is the most common metal of all metals existing on earth today. In addition, it holds third place in the ranking in terms of the number of deposits in the bowels of the Earth. Also, aluminum is the lightest metal. Aluminum ore is a rock that serves as the material from which the metal is obtained.

Aluminum has certain chemical and physical properties that make it possible to adapt its use to completely different areas of human activity. Thus, aluminum has found its wide application in such industries as mechanical engineering, automotive, construction, in the production of various containers and packaging, electrical equipment, and other consumer goods.

Almost every household appliance used by humans every day contains aluminum in one quantity or another.

Aluminum mining

There are a huge number of minerals in which the presence of this metal was once discovered. Scientists have concluded that this metal can be extracted from more than 250 minerals.

However, it is not profitable to extract metal from absolutely all ores, therefore, among all the existing variety, there are the most valuable aluminum ores, from which the metal is obtained. These are: bauxite, nepheline, and alunite. Of all aluminum ores, the maximum aluminum content is found in bauxite.

They contain about 50% of aluminum oxides. As a rule, bauxite deposits are located directly on the earth's surface in sufficient quantities.

Bauxite is an opaque rock that is red or gray in color. The strongest bauxite samples on the mineralogical scale are rated at 6 points. They come in different densities from 2900 to 3500 kg/m3, which directly depends on the chemical composition.

Bauxite ores are distinguished by their complex chemical composition, which includes aluminum hydroxides, iron and silicon oxides, as well as from 40% to 60% of alumina, which is the main raw material for the production of aluminum. It is worth saying that the equatorial and tropical zones of the earth are the main areas that are famous for deposits of bauxite ore.

For the nucleation of bauxite, the participation of several components is necessary, including monohydrate alumina hydrate, boehmite, diaspore, as well as various iron hydroxide minerals along with iron oxide. The weathering of acidic, alkaline, and in some cases basic rocks, as well as the slow settling of alumina at the bottom of reservoirs, leads to the formation of bauxite ore.

From two tons of alumina, aluminum turns out to be half as much - 1 ton. And for two tons of alumina it is necessary to extract about 4.5 tons of bauxite. Aluminum can also be obtained from nephelines and alunites.

The former, depending on their grade, can contain from 22% to 25% alumina. While alunites are slightly inferior to bauxites, and consist of 40% aluminum oxide.

Aluminum ores of Russia

The Russian Federation is ranked 7th among all countries in the world in terms of the amount of aluminum ore mined. It is worth noting that this raw material is mined in colossal quantities on the territory of the Russian state.

However, the country is experiencing a significant shortage of this metal, and is not able to provide it in the volume necessary to absolutely supply the industry.

This is the priority reason why Russia has to purchase aluminum ores from other countries, as well as develop deposits with low quality mineral ores.

There are about 50 deposits in the state, the largest number of which are located in the European part of the state. However, Radynkskoye is the oldest aluminum ore deposit in Russia. Its location is the Leningrad region. It consists of bauxite, which since ancient times has been the main and irreplaceable material from which aluminum is subsequently produced.

Table 1. The largest bauxite deposits in Russia Name % Percentage of total reserves Degree of industrial development

AL2O3	SiO2
"Little Red Riding Hood" Severouralsk	53.7	3.7	3.1	In developing
Kalinskoye, Severouralsk	56.0	2.6	3.6	In developing
Cheremuzovskoye, Sverdlosk region	54.2	4.0	11.0	In developing
Novo-Kalinskoye, Severouralsk	55.0	3.1	7.0	In developing
Iksinskoe, st. Navolok	53.5	17.4	11.4	In developing
Vezhayu-Vorykvinskoye. Komi Republic	49.2	0.1	11.3	In preparation
Vislovskoye, Belgorod	49.1	7.9	12.1	In reserve

Aluminum production in Russia

At the beginning of the twentieth century, the emergence of the aluminum industry took place in Russia. It was in 1932 that the first aluminum production plant appeared in Volkhov. And already on May 14 of the same year, the company managed to receive a batch of metal for the first time.

Every year, new aluminum ore deposits were developed on the territory of the state and new capacities were put into operation, which were significantly expanded during the Second World War.

The post-war period for the country was marked by the opening of new enterprises, the main activity of which was the production of manufactured goods, the main material for which was aluminum alloys. At the same time, the Pikalevsky alumina plant was put into operation.

Russia is famous for its variety of factories, thanks to which the country produces aluminum. Of these, UC Rusal is considered the largest, not only within the Russian state, but throughout the world. He managed to produce about 3.603 million tons of aluminum in 2015, and in 2012 the company reached 4.173 million tons of metal.

Source: http://mining-prom.ru/cvetmet/alyuminiy/alyuminievaya-ruda/

How to extract aluminum from clay

Medieval scientists who comprehended alchemy, from its very inception, sought to learn the secret of creating the philosopher's stone, an artifact capable of transforming any metal into real gold. We spent so much time searching, tested so many technologies, but the technology was not discovered.

But alchemy was able to advance science with its research, and also give rise to such a modern scientific discipline as chemistry. Instead of its great-grandmother alchemy, chemistry today offers us the chance to follow an equally attractive path of enrichment.

Today we will look at the chemical technology that allows the extraction of aluminum from clay.

Technology

The key to achieving a comfortable and prosperous life was literally under your feet all this time. Today we will talk about the so-called bauxite clay. This is a very common raw material.

It contains a significant percentage of aluminum, which, for complete happiness, can only be obtained from bauxite using the technology described here. This material can be found in many places.

For example, it hides under a layer of soil in various pits, along the banks of rivers, lakes and generally near bodies of water.

To tell the truth, you won’t be satisfied with raw materials alone, of course. More space will be required. The ideal option, of course, would be the area of ​​the factory premises in order to immediately gain the ability to produce a large-scale turnover of the extracted goods, but in the beginning an ordinary garage will do. We will achieve the results we need using electric current.

Required Components

Here's a list of things:

• graphite powder
• metal barrel
• welding machine
• concrete mixer
• bauxite clay

Today, the above, with the exception of bauxite, can easily be found among hardware markets and building materials stores. So let's move on from idle theorizing to the practice of this technology.

True, to start you need to find a place where you will get the required raw materials. Drive a car there that can transport loads weighing half a ton. This is exactly the amount of bauxite to be collected. There is no point in taking less than five centners.

When stacking bauxite, consider your strength. Now take what you have collected.

Extraction process

1. As soon as you bring the bauxite, you will need to dry it. You can spread newspapers and lay out the collected early raw materials. After that, take the most ordinary hair dryer. Use it to dry.

Of course, it is much preferable to use some serious drying unit for this purpose. When the weather is sunny, drying can be done outside. However, it is worth remembering that you need to make sure that the dried clay does not dry to anything.

To do this, the surface can be sprinkled with flour or sand, depending on what you have at hand.

2. Now is the time to grab a concrete mixer! Using a concrete mixer, grind the dried early.

Using a concrete mixer, you need to bring it to the state of sand or even dust, since it is much faster and much less expensive to obtain metal with small crumbs than with large pieces. This principle has been known to chemistry for a long time.

For those who do not have a concrete mixer, a simple hammer will be a real salvation. True, it will take a lot of effort to process a whole heap weighing five hundred kilograms. Therefore, it is worth thinking about purchasing a concrete mixer later.

3. It's time to take the graphite powder you bought. Today it will be needed in order to avoid a fire hazard. Next we have to deal with electric current. The resistance of raw materials to electric current passing through it greatly increases the risk of fire. Ordinary graphite powder, on the contrary, reduces resistance and helps control temperature regulation. With its help, it will be much safer to extract from clay. Make a graphite mixture.

4. The main stage comes. Get out your metal barrel. Place the mixture of powders you obtained in the previous step there. Open the tap and fill the mixture in the metal barrel with water. The mixture must be moistened so that the electric current sent through the barrel can freely pass through. Also, with the help of water, we can significantly speed up the process of extracting aluminum from a mixture of powders.

5. The next step is the most important one. Finally, we use electricity using a welding machine. It is imperative to take precautions! Of course, you should wear rubber gloves and boots. This way, avoid possible burns from the electric current of the welding machine.

Following normal safety precautions, connect the welding machine to the metal drum. It is worth waiting fifteen to thirty seconds while the electricity passes through the metal barrel. During this time, oxygen from heating by electric current will leave the powder along with water.

Remove the welding machine.

Result

Don't rush to take the metal from the barrel! He is now very hot from the contact welding machine. It’s worth going to rest and letting the metal cool. Usually three hours is more than enough for a heated metal barrel to cool down. Half a ton of raw material usually yields a quarter ton of aluminum.

The metal obtained from bauxite, of course, is unlikely to be as pure as it is obtained at special ore purification plants. As a result, we will end up with a certain mixture in which the share of aluminum will be from 80% to approximately 90%. Such purity is enough to take what you receive to the nearest point where they accept non-ferrous metals and get money for it.

True, of course, no one will pay the full price there, but even under this condition, it’s possible to earn about a hundred thousand rubles in a month.

The technology of chemistry that was literally on the surface is now known. In general, think about it. Are you ready to take the risk or is the usual boring everyday routine of official employment more pleasant for you than the new prospect that has opened up? Decide.

Source: https://oxmetall.ru/metalli/alyuminij/kak-dobyt-alyuminij-iz-gliny

Aluminum ore: silvery, but not silver

Aluminum is one of the most popular and sought-after metals. In every industry it is not added to the composition of certain items. From instrument making to aviation. The properties of this lightweight, flexible and corrosion-resistant metal have appealed to many industries.

Aluminum itself (a fairly active metal) is practically never found in nature in its pure form and is extracted from alumina, the chemical formula of which is Al2O3. But the direct route to obtaining alumina is, in turn, aluminum ore.

Differences in saturation

Basically, there are only three types of ores worth mentioning that you need to work with if you are mining aluminum. Yes, this chemical element is very, very common, and it can also be found in other compounds (there are about two and a half hundred of them). However, due to the very high concentration, the most profitable extraction will be from bauxite, alunite and nepheline.

Nephelines are an alkaline formation that appeared due to the high temperature of magma. One unit of this ore will yield up to 25% alumina as the main raw material. However, this aluminum ore is considered the poorest for miners. All compounds containing alumina in even smaller quantities than nephelines are obviously recognized as unprofitable.

Alunites were formed during volcanic as well as hydrothermal activities. They contain up to 40% of the essential alumina, being the “golden mean” in our trinity of ores.

And the first place, with a record aluminum oxide content of fifty percent or more, goes to bauxite! They are rightfully considered the main source of alumina. However, regarding their origin, scientists still cannot come to the only correct decision.

Either they migrated from their original place of origin and were deposited after the ancient rocks weathered, or they turned out to be sediment after some limestones dissolved, or they generally became the result of the decomposition of iron, aluminum and titanium salts, falling out as sediment. In general, the origin is still unknown. But the fact that bauxite is the most profitable is already certain.

Aluminum mining methods

The necessary ores are mined in two ways.

In terms of the open method of mining the treasured Al2O3 in aluminum deposits, the three main ores are divided into two groups.

Bauxite and nepheline, as higher density structures, are cut by milling using a surface miner. Of course, it all depends on the manufacturer and model of the machine, but, on average, it is capable of removing up to 60 centimeters of rock at a time. After a complete passage of one layer, a so-called shelf is created. This method ensures that the combine operator remains safe in his position. In the event of a collapse, both the chassis and the operator's cab will be safe.

The second group contains alunites, which, due to their friability, are mined by quarry excavators and then unloaded onto dump trucks.

A radically different method is to punch a shaft. Here the mining principle is the same as in coal mining. By the way, the deepest aluminum mine in Russia is the one located in the Urals. The depth of the mine is 1550m!

Processing the resulting ore

Next, regardless of the chosen extraction method, the resulting minerals are sent to processing workshops, where special crushing devices break the minerals into fractions approximately 110 millimeters in size.

The next step is to obtain additional chemicals. additives and transportation to the further stage, which is sintering the rock in furnaces.

Having gone through decomposition and received an aluminate pulp at the exit, we will send the pulp to be separated and drained from the liquid.

At the final stage, what is obtained is cleaned from alkalis and sent back to the oven. This time - for calcination. The finale of all actions will be the same dry alumina that is needed to obtain aluminum through hydrolysis.

Even though opening a shaft is considered a more difficult method, it is less harmful to the environment than the open method. If you are for the environment, you know what to choose.

Aluminum mining in the world

At this point we can say that indicators for interactions with aluminum around the world are divided into two lists. The first list will include countries that own the largest natural reserves of aluminum, but perhaps not all of these riches have time to process. And the second list contains the world leaders in the direct extraction of aluminum ore.

So, in terms of natural (although not realized everywhere, yet) wealth, the situation is like this:

1. Guinea
2. Brazil
3. Jamaica
4. Australia
5. India

These countries can be said to have the vast majority of Al2O3 in the world. They account for 73 percent in total. The remaining reserves are scattered around the globe in less generous quantities. Guinea, located in Africa, is, in a global sense, the largest deposit of aluminum ores in the world. It “grabbed” 28%, which is even more than a quarter of the global deposits of this mineral.

And this is how things stand with the processes of mining aluminum ore:

1. China is in first place and produces 86.5 million tons;
2. Australia is a country of strange animals with its 81.7 million. tons in second place;
3. Brazil - 30.7 million tons;
4. Guinea, being the leader in reserves, is only in fourth place in terms of production - 19.7 million tons;
5. India – 14.9 million tons.

You can also add to this list Jamaica, capable of producing 9.7 million tons, and Russia, with its figure of 6.6 million tons.

Aluminum in Russia

Regarding aluminum mining in Russia, only the Leningrad region and, of course, the Urals, as a true storehouse of mineral resources, can boast of certain indicators. The main method of extraction is mining. They mine four-fifths of all ore in the country. In total, on the territory of the Federation there are more than four dozen deposits of nepheline and bauxite, the resources of which will definitely be enough even for our great-great-grandchildren.

However, Russia also imports alumina from other countries. This is because local substances (for example, the Red Cap deposit in the Sverdlovsk region) contain only half of alumina. Whereas Chinese or Italian rocks are saturated with Al2O3 by sixty percent or more.

Looking at some of the difficulties with aluminum mining in Russia, it makes sense to think about the production of secondary aluminum, as the UK, Germany, USA, France and Japan have done.

Application of aluminum

As we already stated at the beginning of the article, the range of applications of aluminum and its compounds is extremely wide. Even at the stages of extraction from the rock, it is extremely useful. The ore itself, for example, contains small quantities of other metals, such as vanadium, titanium and chromium, useful for steel alloying processes. There is also a benefit at the alumina stage, because alumina is used in ferrous metallurgy as a flux.

The metal itself is used in the production of thermal equipment, cryogenic technology, participates in the creation of a number of alloys in metallurgy, and is present in the glass industry, rocketry, aviation, and even in the food industry as an E173 additive.

So, only one thing is certain. For many more years, humanity's need for aluminum, as well as its compounds, will not fade away. Which, accordingly, speaks exclusively of an increase in its production volumes.

Source: https://geomix.ru/blog/minerals/alyuminievaya-ruda/

Where is aluminum mined in Russia?

Aluminum is a metal coated with a matte silver oxide film, the properties of which determine its popularity: softness, lightness, ductility, high strength, corrosion resistance, electrical conductivity and lack of toxicity. In modern high technologies, the use of aluminum is given a leading place as a structural, multifunctional material.

The greatest value for industry as a source of aluminum is natural raw materials - aluminum ore , a component of rock in the form of bauxite, alunite and nepheline.

Varieties of alumina-containing ores

More than 200 minerals are known that contain aluminum.

Only rock that can meet the following requirements is considered a raw material source:

• Natural raw materials must have a high content of aluminum oxides;
• The deposit must correspond to the economic feasibility of its industrial development.
• The rock must contain aluminum raw materials in a form that can be extracted in its pure form by known methods.

Feature of the natural rock bauxite

Natural deposits of bauxite, nepheline, alunite, clay, and kaolin can serve as a source of raw materials. Bauxite is the most saturated with aluminum compounds.

Clays and kaolins are the most common rocks with a significant alumina content. Deposits of these minerals are found on the surface of the earth.

Aluminum ore in nature exists only in the form of a binary compound of metal with oxygen.

This compound is extracted from natural mining ores in the form of bauxite, consisting of oxides of several chemical elements: aluminum, potassium, sodium, magnesium, iron, titanium, silicon, phosphorus.

Depending on the deposit, bauxite contains from 28 to 80% alumina. This is the main raw material for obtaining a unique metal.

The quality of bauxite as an aluminum raw material depends on its alumina content.

This determines the physical properties of bauxite:

• The mineral has a hidden crystalline structure or is in an amorphous state. Many minerals have hardened forms of hydrogels of simple or complex composition.
• The color of bauxite at different mining locations ranges from almost white to dark red. There are deposits with a black color of the mineral.
• The density of aluminum-containing minerals depends on their chemical composition and is about 3,500 kg/m3.
• The chemical composition and structure of bauxite determines the solid properties of the mineral. The strongest minerals have a hardness of 6 units on the scale accepted in mineralogy.
• As a natural mineral, bauxite has a number of impurities, most often these are oxides of iron, calcium, magnesium, manganese, and impurities of titanium and phosphorus compounds.

Bauxites, kaolins, and clays contain impurities of other compounds, which are separated into separate industries during the processing of raw materials.

Only in Russia do they use deposits with rock deposits that contain lower concentrations of alumina.

Recently, alumina began to be obtained from nephelines, which, in addition to alumina, contain oxides of metals such as potassium, sodium, silicon and, no less valuable, alum stone, alunite.

Methods for processing aluminum containing minerals

The technology for producing pure alumina from aluminum ore has not changed since the discovery of this metal.

Its production equipment is being improved, allowing it to produce pure aluminum.

The main production stages of obtaining pure metal:

• Extraction of ore from developed deposits.
• Primary processing of waste rocks in order to increase the concentration of alumina is an enrichment process.
• Preparation of pure alumina, electrolytic reduction of aluminum from its oxides.

The production process ends with metal with a concentration of 99.99%.

Alumina mining and beneficiation

Alumina or aluminum oxides do not exist in nature in their pure form. It is extracted from aluminum ores using hydrochemical methods.

Deposits of aluminum ore in deposits are usually blasted , providing a site for its extraction at a depth of approximately 20 meters, from where it is removed and launched into the process of further processing;

• Using special equipment (screens, classifiers), the ore is crushed and sorted, discarding waste rock (tailings). At this stage of alumina enrichment, washing and screening methods are used as the most economically advantageous.
• The purified ore settled at the bottom of the concentration plant is mixed with a heated mass of caustic soda in an autoclave.
• The mixture is passed through a system of high-strength steel vessels. The vessels are equipped with a steam jacket that maintains the required temperature. The steam pressure is maintained at 1.5-3.5 MPa until the aluminum compounds are completely transferred from the enriched rock to sodium aluminate in a superheated sodium hydroxide solution.
• After cooling, the liquid undergoes a filtration stage, as a result of which solid sediment is separated and a supersaturated pure aluminate solution is obtained. By adding aluminum hydroxide residues from the previous cycle to the resulting solution, decomposition is accelerated.
• For final drying of aluminum oxide hydrate, a calcination procedure is used.

Electrolytic production of pure aluminum

Pure aluminum is produced using a continuous process in which calcined aluminum enters the electrolytic reduction stage .

Modern electrolysers are a device consisting of the following parts:

• Made of steel casing lined with coal blocks and slabs. During operation, a dense film of frozen electrolyte is formed on the surface of the bath body, protecting the lining from destruction by the electrolyte melt.
• A layer of molten aluminum at the bottom of the bath, 10–20 cm thick, serves as the cathode in this installation.
• Current is supplied to the aluminum melt through carbon blocks and embedded steel rods.
• The anodes, suspended on an iron frame using steel pins, are provided with rods connected to a lifting mechanism. As combustion proceeds, the anode moves down, and the rods are used as an element for supplying current.
• In workshops, electrolyzers are installed sequentially in several rows (two or four rows).

Source: https://steelfactoryrus.com/gde-dobyvayut-alyuminiy-v-rossii/

Aluminum industry

articles

Aluminum industry. In 1854 A. Deville invented the first practical method for the industrial production of aluminum. Production growth was particularly rapid during and after World War II.

Primary aluminum production (excluding Soviet production) was only 620 thousand tons in 1939, but increased to 1.9 million tons in 1943. By 1956, 3.4 million were produced worldwide.

t primary aluminum; in 1965, global aluminum production amounted to 5.4 million tons, in 1980 – 16.1 million tons, in 1990 – 18 million tons.

Aluminum production includes three main stages: mining and beneficiation of ore; obtaining pure aluminum oxide (alumina) from ore; reduction of aluminum from oxide by electrolysis.

Ore mining and beneficiation

The main aluminum ore, bauxite, is mined mainly in quarries; The largest producers of bauxite are Australia, Guinea, Jamaica and Brazil. Typically, the ore layer is blasted to form a working platform at a depth of up to 20 m, and then removed. The ore pieces are crushed and sorted using screens and classifiers.

The crushed ore is further beneficiated and the waste rock (tailings) is discarded. At this stage of the process, it is economical to use washing and screening methods, which use the difference in densities of the ore and gangue to separate them from each other. Less dense gangue is carried away by the wash water, and the concentrate settles to the bottom of the concentration plant. Cm.

also ORE ENRICHMENT.

Bayer process

The process of producing pure alumina involves heating bauxite with caustic soda, filtering, precipitating the aluminum hydroxide and calcining it to release pure alumina. In practice, the ore is mixed with the required amount of hot caustic soda in a mild steel autoclave, and the mixture is pumped through a series of steam-jacketed steel vessels.

A steam pressure of 1.4–3.5 MPa is maintained in the vessels for a period of time from 40 minutes to several hours, until the transition of aluminum oxide from bauxite to a solution of sodium aluminate in a superheated liquid is completed. After cooling, the solid precipitate is separated from the liquid. The liquid is filtered; the result is a supersaturated pure aluminate solution.

This solution is metastable: the aluminate ion decomposes to form aluminum hydroxide. Adding crystalline aluminum hydroxide remaining from the previous cycle to the solution accelerates decomposition. The dry aluminum hydroxide crystals are then calcined to separate out the water. The resulting anhydrous alumina is suitable for use in the Hall–Heroult process.

For economic reasons, industry tends to make these processes as continuous as possible.

Hall–Heroux electrolysis

The final stage of aluminum production involves its electrolytic reduction from pure alumina obtained in the Bayer process. This method of extracting aluminum is based on the fact (discovered by Hall and Heroux) that when alumina is dissolved in molten cryolite, aluminum is released during electrolysis of the solution.

A typical Hall-Heroult cell is a bath of molten cryolite 3NaF x AlF3 (Na3AlF6) - double sodium and aluminum fluoride, in which 3-5% alumina is dissolved - floating on a bed of molten aluminum.

Steel bars passing through a hearth of carbon slabs are used to apply voltage to the cathode, and suspended carbon bars immersed in molten cryolite serve as anodes. The operating temperature of the process is close to 950° C, which is significantly higher than the melting point of aluminum.

The temperature in the electrolysis bath is regulated by changing the gap between the anodes and the cathode metal receiver, onto which molten aluminum is deposited. To maintain optimal temperature and alumina concentration, modern electrolysers use complex control systems.

Aluminum production requires a lot of energy, so the energy efficiency of the process is a major concern in the aluminum industry. Electrode reactions are the reduction of aluminum from its oxide and the oxidation of carbon to its oxide and dioxide at the anodes. One furnace produces up to 2.2 tons of aluminum per day. The metal is drained once a day (or less often), then fluxed and degassed in a reverberatory hoarding furnace and poured into molds.

Renewable Soderberg electrodes

In the Hall-Heroux electrolyzer, carbon anodes are consumed at a rate of 2.5 cm/day, so that the installation of new anodes is often required. To eliminate frequent human intervention in production, a process using a renewable Soderberg electrode was developed.

The Soderberg anode is continuously formed and sintered in a reduction chamber from a paste - a mixture of 70% ground coke and 30% resin binder. This mixture is packed into a rectangular sheet steel shell, open at both ends and positioned vertically above the molten bath inside the furnace. As the anode is consumed, paste is added to the upper hole of the shell.

When the coke-tar mixture is lowered and heated, it is sintered into a hard carbon block before it reaches the work area.

Aluminum consumption

About 28% of aluminum produced is used to make beverage cans, food containers and all kinds of packaging. Another 17% is used in vehicles, including aircraft, military equipment, railroad cars and automobiles. About 16% is used in building structures.

About 8% is used in high-voltage power lines and other electrical devices, and 7% in consumer products such as refrigerators, air conditioners, washing machines and furniture. 6% is spent on the needs of mechanical engineering and industrial equipment.

The remainder of the aluminum consumed is used in the production of television antennas, pigments and paints, spacecraft and ships. See also HALL, CHARLES MARTIN.

Source: https://www.krugosvet.ru/enc/nauka_i_tehnika/tehnologiya_i_promyshlennost/ALYUMINIEVAYA_PROMISHLENNOST.html

Methods for producing aluminum (page 1 of 3)

Aluminum is the most important metal; its production volume is far ahead of the production of all other non-ferrous metals and is second only to steel production. The high growth rate of aluminum production is due to its unique physical and chemical properties, thanks to which it has found wide application in electrical engineering, aircraft and automobile construction, transport, production of household appliances, construction, food packaging, etc.

The aluminum industry of Russia, created in Soviet times, occupies a dominant position in the production of non-ferrous metals in the country and is in second place in the world in metal production.

In recent years, for well-known reasons, aluminum production technology has not been modernized at all, electrolysis technology has not been improved, the volume of scientific research has been unacceptably reduced and noticeably lags behind advanced countries.

At the same time, equipment is being widely modernized abroad and technology is being improved, which has dramatically increased the economic efficiency and environmental safety of aluminum production.

Recently, mechanical engineering has increasingly required light metals, especially in aircraft construction and railway transport. Therefore, the development of new and more economical methods for producing aluminum and the improvement of existing methods is of great importance.

1. History of the development of the aluminum industry

Currently, aluminum ranks first among non-ferrous metals in terms of production volume, and its production is constantly expanding.

Historically, the first mention of aluminum metal was in the writings of First Century Roman. The following story can be found in the famous encyclopedia Historia naturalis. One day, a Roman goldsmith was allowed to show Emperor Tiberius a dinner plate made of the new metal. The plate was very light and shone like silver.

The jeweler told the emperor that he had extracted the metal from ordinary clay. He also assured the emperor that only he and the gods knew how to make metal from clay. The Emperor became very interested. However, he immediately realized that his entire treasury, consisting of gold and silver, would fall into decay if people began to produce this light metal from clay.

Therefore, instead of the reward the jeweler expected, he was beheaded.

It is not known how true this story is, but the events described took place 2000 years before mankind discovered a method for producing aluminum. This happened in 1825, when the Danish physicist G. Oersted obtained several milligrams of aluminum metal by thermal reduction of aluminum chloride with potassium amalgam.

Considerable difficulties in obtaining aluminum arose due to the following factors:

- high affinity of aluminum for oxygen. Aluminum can be reduced by carbon from its oxide at a temperature of about 2000°C. However, already at 1200°C carbon reacts with aluminum, giving carbide;

— high electrochemical potential of aluminum (-1.67V). It is impossible to obtain aluminum from aqueous solutions, since the process of hydrogen evolution (decomposition of water) will practically take place at the cathode;

— high melting point of alumina (2050°C), which excludes the possibility of electrolysis of molten alumina.

Industrial production of aluminum is associated with the name of the Frenchman Henri Saint-Clair Deville. He was well aware of the experiments of G. Oersted and another scientist, F. Wöhler, who in 1827 managed to isolate grains of aluminum. The reason for F. Wöhler's failure was that these grains in air were immediately covered with a thin film of aluminum oxide.

First of all, A.S.-K. Deville, in the process of obtaining the metal, replaces potassium with cheaper sodium and conducts laboratory experiments on a large scale.

The resulting aluminum chloride was loaded into a large steel pipe, in which vessels filled with metallic sodium were placed at equal distances from each other.

When heated, aluminum chloride interacted with sodium in the gas phase and aluminum particles settled to the bottom of the pipe. The grains formed as a result of the reaction were carefully collected, melted and metal ingots were obtained.

The new method of producing aluminum turned out to be very labor-intensive. In addition, the interaction of aluminum chloride vapor with sodium often occurs explosively. In laboratory conditions this did not pose a serious danger, but in factory conditions it could cause a disaster. A.S.-K.

Deville replaced aluminum chloride with a mixture of AlC13 and NaCl. Now the participants in the reaction were in a molten state.

The explosions stopped, but, most importantly, instead of small beads of metal that had to be collected by hand, a significant amount of liquid aluminum was obtained.

Experiments at the Javel plant were successful. In 1855, the first metal ingot weighing 6–8 kg was obtained.

The baton of aluminum production using chemical methods was continued by the Russian scientist N. N. Beketov. He carried out a reaction between cryolite (Na3AlF6) and magnesium. The method of N.N. Beketov was not much different from the method of A.S.-K. Deville, but it was simpler. In the German city of Gmelingham in 1885, a plant was built using the method of N.N. Beketov, where in five years 58 tons of aluminum were produced - more than a quarter of the total world production of the metal by chemical means in the period from 1854 to 1890.

The production of aluminum by chemical methods could not provide the industry with cheap metal. It was low-productive and did not produce pure aluminum without impurities. This forced researchers around the world to look for new ways to produce aluminum.

Electric current came to the aid of scientists. Back in 1808, G. Davy tried to decompose alumina using a powerful electric battery, but without success. Almost 50 years later, R. Bunsen and A.S.-K.

Deville independently carried out the electrolysis of a mixture of aluminum and sodium chlorides. They were luckier than their predecessor and managed to obtain small droplets of aluminum. However, in those days there were no cheap and sufficiently powerful sources of electricity.

Therefore, the electrolysis of aluminum was of only purely theoretical interest.

In 1867, the dynamo was invented, and soon they learned how to transmit electricity over long distances. Electricity began to invade industry.

In 1886, P. Héroult in France and C. Hall in the USA almost simultaneously laid the foundation for the modern method of producing aluminum, proposing to produce it by electrolysis of alumina dissolved in molten cryolite (Hall-Héroux method). From this point on, a new method of producing aluminum began to develop rapidly, facilitated by improvements in electrical engineering, as well as the development of methods for extracting alumina from aluminum ores.

A significant 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. Tsarist Russia did not have its own aluminum industry. However, the first theoretical studies in the field of aluminum electrolysis belonged to the outstanding Russian scientist, the founder of electrometallurgy of non-ferrous metals in our country, prof. P. P. Fedotiev. In 1912, together with V.P.

Ilyinsky published the work “Experimental; Research on Electrometallurgy of Aluminum", which was immediately translated into many foreign languages ​​and became a reference book for metallurgists around the world. P.P. Fedotiev and Ilyinsky at the St. Petersburg Polytechnic Institute (S.

Petersburg State Technical University) conducted thorough research on the selection of the optimal electrolyte composition, and also found out how the addition of sodium, aluminum and calcium fluorides affects the solubility of alumina in cryolite and the crystallization temperature.

On March 28, 1929, a note was published in the Leningradskaya Pravda newspaper, which reported that at the pilot plant of the Krasny Vyborgets plant, for the first time, 8 kg of aluminum metal was obtained from one bath. This marked the beginning of our aluminum industry.

In 1931 The Research Institute of Aluminum-Magnesium Industry (VAMI) was organized in 1932. Volkhovsky was launched, and in 1933 – Dneprovsky aluminum smelters. Since then, the aluminum industry has begun to develop rapidly in various parts of the country.

2. Basics of electrolysis of cryolite-alumina melts

Electrolysis of cryolite-alumina melts is the main method for producing aluminum, although some aluminum alloys are produced by electrothermal methods.

The first industrial electrolysers had a current strength of up to 0.6 kA and over the next 100 years it increased to 300 kA. However, this did not make significant changes to the fundamentals of the production process.

The general scheme of aluminum production is shown in Fig. 2.1. The main unit is the electrolyzer. The electrolyte is a melt of cryolite with a slight excess of aluminum fluoride, in which alumina is dissolved. The process is carried out at variable alumina concentrations from approximately 1 to 8% (wt.). A carbon anode, partially immersed in the electrolyte, is lowered into the bath from above.

There are two main types of sacrificial anodes: self-baking and pre-baked. The first use the heat of electrolysis to fire the anode mass, consisting of a mixture of coke filler and a binder - pitch. Baked anodes are a pre-baked mixture of coke and pitch binder. The technology for the production of anode mass and baked anodes is described in detail in the literature (see.

, for example, [3, 4]).

Rice. 2.1. Scheme for the production of aluminum from alumina.

Molten aluminum at the electrolysis temperature (950–960°C) is heavier than the electrolyte and is located at the bottom of the electrolyzer. Cryolite-alumina melts are very aggressive, which can be resisted by carbonaceous and some new materials. These are used to make the internal lining of the electrolyzer.

Source: https://mirznanii.com/a/324948/sposoby-polucheniya-alyuminiya

Guide to Last Day on Earth

A detailed guide dedicated to the game Last Day on Earth: Survival, searching and mining aluminum, making aluminum ingots and wires

• Recipe guide for Last Day on Earth: Survival
• Guide to enemies in Last Day on Earth: Sruvival
• Guide to collecting loot in Last Day on Earth: Survival

Finally, aluminum ingots and wires have been added to the mobile game Last Day on Earth: Survival , which is why players around the world are trying to find and get their hands on them. Unfortunately, as is the case with many game items, it is not entirely clear where exactly to look for them.

In our current guide, we'll look at ways to obtain both items.

How to get aluminum ingots in Last Day on Earth: Survival

To get aluminum ingots in Last Day on Earth: Survival , you will first need to build a smelter, the blueprint for which will become available from level six.

After obtaining 10 pieces of limestone and five pieces of iron ore for the furnace, you will be able to create aluminum ingots. To do this, melt two aluminum wires into one aluminum ingot. Please note that the melting process may take about 25 minutes.

How to get aluminum wires in Last Day on Earth: Survival

Now that you know what you need to get aluminum ingots, you need to decide where to look for aluminum wires. Unfortunately, getting them won't be easy.

Aluminum wire can be found by searching the first and second floors of Bunker Alpha. While player reports indicate a greater likelihood of finding wires on the second floor of the bunker, there is still a chance of getting them on the first tier.

But you must understand that the second floor of the bunker is much more dangerous than the first. Therefore, it is up to you to decide whether the higher probability of receiving aluminum wires is worth the risk or not.

If you still don’t know how to gain access to the Alpha bunker, we recommend that you read our other guide.

How to use aluminum in Last Day on Earth: Survival

Now that you have a large supply of aluminum ingots in your inventory, you can use them to craft various items. For 15 pine planks, 25 iron ingots, 20 rubber parts, 10 aluminum ingots and 20 nails you can build a weapons shop. This is a valuable piece of furniture that will give you access to the development of absolutely all types of weapons.

In addition, you can spend four aluminum ingots, four weapon parts, five electrical tapes and three bolts to create a defensive turret.

Having aluminum ingots and wires on hand will make it much easier for you to stay alive.

Source: https://rankbrain.ru/gayd-po-last-day-on-earth-kak-dobyt-alyuminiy.html

How is aluminum ore mined and where is it used?

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

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

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

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

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

Bauxite ore is the basis of global aluminum production

The silver metal itself is directly obtained from alumina.

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

• Bauxite;
• Alunitov;
• Nepheline syenites.

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

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

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

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

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

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

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

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

Properties of aluminum ore

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Leading countries in aluminum ore production

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

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

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

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

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

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

Development of aluminum ore deposits in Russia

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

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

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

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

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

Applications of Aluminum Ore

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

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

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

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

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

Alternative to aluminum ores

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

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

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

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