Iron ores are the basis of modern production. How iron ore is mined (72 photos) Main iron deposits

Iron ore is a natural mineral formation that contains iron compounds accumulated in such a volume that is sufficient for its economic extraction. Of course, all rocks contain iron. But iron ores are precisely those ferrous compounds that are so rich in this substance that they allow the industrial extraction of metallic iron.

Types of iron ores and their main characteristics

All iron ores differ greatly in their mineral composition and the presence of harmful and beneficial impurities. The conditions of their formation and, finally, the iron content.

The main materials that are classified as ore can be divided into several groups:

• Iron oxides, which include hematite, martite, magnetite.
• Iron hydroxides - hydrogoethite and goethite;
• Silicates - thuringite and chamosite;
• Carbonates - sideroplesite and siderite.

Industrial iron ores contain iron in varying concentrations - from 16 to 72%. Beneficial impurities contained in iron ores include: Mn, Ni, Co, Mo, etc. There are also harmful impurities, which include: Zn, S, Pb, Cu, etc.

Iron ore deposits and mining technology

According to their genesis, existing iron ore deposits are divided into:

• Endogenous. They can be igneous, representing inclusions of titanomagnetite ores. There may also be carbonatite inclusions. In addition, there are lens-shaped, sheet-like skarn-magnetite deposits, volcano-sedimentary strata deposits, hydrothermal veins, as well as irregularly shaped ore bodies.
• Exogenous. These mainly include brown iron ore and siderite sedimentary layer deposits, as well as deposits of thuringite, chamosite and hydrogoethite ores.
• Metamorphogenic are deposits of ferruginous quartzites.

The maximum volumes of ore production are provoked by significant reserves and fall on Precambrian ferruginous quartzites. Sedimentary brown-iron ores are less common.

During mining, a distinction is made between rich ores and those requiring enrichment. The industry that produces iron ore also carries out its preliminary processing: sorting, crushing and the above-mentioned beneficiation, as well as agglomeration. The ore mining industry is called the iron ore industry and is the raw material base for ferrous metallurgy.

Applications

Iron ore is the main raw material for producing cast iron. It goes to open-hearth or converter production, as well as for iron recovery. As is known, a wide variety of products are made from iron, as well as from cast iron. The following industries need these materials:

• Mechanical engineering and metalworking;
• Automotive industry;
• Rocket industry;
• Military industry;
• Food and light industry;
• Building sector;
• Oil and gas production and transportation.

In addition to the well-known oil and gas, there are other equally important minerals. These include ores that are mined for ferrous and through processing. The presence of ore deposits is the wealth of any country.

What are ores?

Each of the natural sciences answers this question in its own way. Mineralogy defines ore as a set of minerals, the study of which is necessary to improve the processes of extracting the most valuable of them, and chemistry studies the elemental composition of ore in order to identify the qualitative and quantitative content of valuable metals in it.

Geology addresses the question: “What are ores?” from the point of view of the feasibility of their industrial use, since this science studies the structure and processes occurring in the bowels of the planet, the conditions for the formation of rocks and minerals, and the exploration of new mineral deposits. They are areas on the Earth's surface on which, as a result of geological processes, a sufficient amount of mineral formations has accumulated for industrial use.

Ore formation

Thus, to the question: “what are ores?” The most complete answer is this. Ore is a rock with an industrial content of metals in it. Only in this case does it have value. Metal ores are formed when the magma that contains their compounds cools. At the same time, they crystallize, distributed according to their atomic weight. The heaviest ones settle to the bottom of the magma and are separated into a separate layer. Other minerals form rocks, and the remaining hydrothermal fluid from the magma spreads into the voids. The elements contained in it solidify and form veins. Rocks, being destroyed under the influence of natural forces, are deposited at the bottom of reservoirs, forming sedimentary deposits. Depending on the composition of rocks, various metal ores are formed.

Iron ores

The types of these minerals vary significantly. What are ores, in particular iron ores? If the ore contains a sufficient amount of metal for industrial processing, it is called iron. They differ in origin, chemical composition, and content of metals and impurities that may be beneficial. As a rule, these are associated non-ferrous metals, for example, chromium or nickel, but there are also harmful ones - sulfur or phosphorus.

The chemical composition is represented by its various oxides, hydroxides or carbon dioxide salts of iron oxide. The ores being mined include red, brown and magnetic iron ore, as well as iron luster - they are considered the richest and contain more than 50% metal. Poor ones include those in which the useful composition is less - 25%.

Composition of iron ore

Magnetic iron ore is iron oxide. It contains more than 70% pure metal, but in deposits it is found together with and sometimes with zinc blende and other formations. considered the best ore in use. Iron luster also contains up to 70% iron. Red iron ore - iron oxide - is one of the sources of pure metal extraction. And brown analogues have up to 60% metal content and are found with impurities, sometimes harmful. They are hydrous iron oxide and accompany almost all iron ores. They are also convenient for their ease of extraction and processing, but the metal obtained from this type of ore is of low quality.

Based on the origin of iron ore deposits, they are divided into three large groups.

1. Endogenous, or magmatic. Their formation is due to geochemical processes occurring in the depths of the earth's crust and magmatic phenomena.
2. Exogenous, or surface, deposits were created as a result of processes occurring in the near-surface zone of the earth's crust, that is, at the bottom of lakes, rivers, and oceans.
3. Metamorphogenic deposits were formed at a sufficient depth from the earth's surface under the influence of high pressure and the same temperatures.

Iron ore reserves in the country

Russia is rich in various deposits. The largest in the world - it contains almost 50% of all world reserves. It was noted in this region already in the 18th century, but the development of deposits began only in the 30s of the last century. The ore reserves in this basin have a high content of pure metal, they are measured in billions of tons, and mining is carried out by open-pit or underground methods.

The Bakchar iron ore deposit, which is one of the largest in the country and the world, was discovered in the 60s of the last century. Its ore reserves with a concentration of pure iron up to 60% amount to about 30 billion tons.

In the Krasnoyarsk Territory there is the Abagaskoe deposit - with magnetite ores. It was discovered back in the 30s of the last century, but its development began only half a century later. In the Northern and Southern zones of the basin, mining is carried out by open-pit mining, and the exact amount of reserves is 73 million tons.

Discovered back in 1856, the Abakan iron ore deposit is still active. At first, the development was carried out by opencast mining, and from the 60s of the 20th century - underground mining at a depth of up to 400 meters. The content of pure metal in the ore reaches 48%.

Nickel ores

What are nickel ores? The mineral formations that are used for the industrial production of this metal are called nickel ores. There are sulfide copper-nickel ores with a pure metal content of up to four percent and silicate nickel ores, the same figure being up to 2.9%. The first type of deposits is usually of the igneous type, and silicate ores are found in areas of the weathering crust.

The development of the nickel industry in Russia is associated with the development of their location in the Middle Urals in the mid-19th century. Almost 85% of sulfide deposits are concentrated in the Norilsk region. The deposits in Taimyr are the largest and most unique in the world in terms of the wealth of reserves and diversity of minerals; they contain 56 elements of the periodic table. The quality of nickel ores in Russia is not inferior to other countries; the advantage is that they contain additional rare elements.

About ten percent of nickel resources are concentrated in sulfide deposits on the Kola Peninsula, and silicate deposits are being developed in the Middle and Southern Urals.

The ores of Russia are characterized by the quantity and variety necessary for industrial use. However, at the same time, they are distinguished by difficult natural production conditions, uneven distribution across the country, and a discrepancy between the region where resources are located and the population density.

The raw material base of each metallurgical region has its own specific characteristics, which largely determine the technology of the entire cycle of the metallurgical plant and its economy. As we already said in the section “what is iron ore? ", iron ore reserves on our planet are estimated at approximately 150 billion tons, and the richest countries in terms of iron are: Russia, Brazil, Australia, Ukraine, China, India and the USA.

Let's first consider the most significant deposits iron ore in Ukraine.

Krivoy Rog field in the area of ​​Krivoy Rog gives. The ore, locally obtained concentrate and produced pellets are used at the Krivoy Rog Metallurgical Plant and are also exported abroad. The ore lies at a depth of up to 500 m, but quartzites come to the surface. Therefore, development is carried out in both open and closed ways. Reserves of rich ores (hematites and martites) are estimated at 1.2 billion tons, and reserves of quartzites (magnetite and oxidized hematite) - up to 18 billion tons.

Open pit mining of iron ore

The average iron content in ore is about 55%, and in mined magnetite quartzites - 35-37%. The gangue consists almost entirely of silica. The ore does not contain harmful impurities. The rich ore is crushed on site and sorted by particle size. The 0-10 mm fraction is sent to sintering, and >10 mm is sent directly to blast furnace shops. Magnetite quartzites are enriched by magnetic separation. From the concentrate, containing about 65% iron, agglomerate, pellets are produced, or it is sent to metallurgical plants. The Kremenchug field, located northeast of Krivoy Rog, is its continuation. It contains 1.1 billion tons of magnetite quartzites containing about 30% iron, which are enriched at the Poltava Mining and Processing Plant built here to 65% iron, and pellets are produced from the concentrate.

Beloretskoye field, located near the city of Zaporozhye, is represented by rich hematite ores containing about 63% iron. The reserves amount to 500 million tons. The Zaporozhye Mining and Processing Plant located here processes the mined ore, after which it is sent directly to the factories.

Kerch field brown iron ore has reserves of about 2 billion tons. The ore is an oolitic (granular) brown iron ore containing 34-39% iron. Low iron content, high content of harmful impurities (about 1% phosphorus, 0.05-0.15% arsenic) and enrichment difficulties have led to the fact that this deposit is currently not used.

Russia is the richest country in iron ores, and Kursk magnetic anomaly, the largest iron ore region in the world. The magnetic anomaly of this area, which is 50-100 km wide and 400-600 km long. caused by a thick thickness of steeply dipping quartzite layers, representing practically inexhaustible reserves of iron. The ore layers are located at a depth of 35-580 m. The registered reserves of the Kursk magnetic anomaly exceed 40 billion tons, and the promising ones - up to 200 billion tons. The main reserves of the deposit are represented by quartzites, mainly magnetite, containing 35-40% Fe, and rich hematite -martite ores containing 50-61% Fe. In addition, these ores contain 0.1-0.6% S, 0.02-0.09% P and 10-20% hygroscopic moisture.

A negative feature of waste rock is the increased (up to 2.5-3.5%) alumina content, which worsens the properties of the slag. The largest deposits are Mikhailovskoe(near Kursk), Lebedinskoye And Stoilenskoye(near the city of Gubkin). They are developed by open-pit mining, quartzite is enriched, pellets are produced from the concentrate at mining and processing plants, and part of the concentrate is sent directly to the plants.

Shown in the photo

We also bring to your attention a short video about the work of the Stoilensky Mining and Processing Plant, so that you can imagine how the extraction and further processing of iron ore occurs.

The Yakovlevskoye, Gostishchevskoye and other deposits located near Belgorod are promising, the reserves of which amount to about 25 billion tons of rich hematite-martite ores, which, however, occur at depths of about 500 m.

In the Murmansk region and Karelia there are several iron ore deposits, which are the base of the Cherepovets Metallurgical Plant.

Olenegorskoye field, located south of Murmansk, consists of ferruginous quartzites containing about 31% iron. Its reserves amount to about 600 million tons. They are enriched on site using the magnetic-gravity method at the Olenegorsk GOK to a content of 62% Fe, and the concentrate is supplied to sinter plants.

Shown in the photo

Eno-Kovdorskoye field, located west of Olenegorsk, is represented by magnetite quartzites containing 31-32% Fe, has a thickness of about 500 million tons. Its peculiarity is the main waste rock, which has a basicity index of 1.6 and a high phosphorus content, which decreases after magnetic enrichment at the Kovdorsky GOK from 2.7-2.9% to only 0.18-0.20%. The concentrate containing 64-65% Fe is sent to plants for sintering.

Kostamuksha field magnetite quartzites with a capacity of about 1.2 billion tons are located in the Karelian Autonomous Soviet Socialist Republic, on the border with Finland. Quartzites containing 30-35% Fe, about 0.07% P and 0.2% S are enriched at the mining and processing plant built here to a content of 63-65% Fe, from which pellets are produced, sent to the Cherepovets Metallurgical Plant.

Kachkanarskoye field titanomagnetites is located north of Nizhny Tagil, has reserves of about 12 billion tons. The extremely low iron content (only 16-17%) increases to 61% during the enrichment process. The ore contains about 0.15% vanadium, which is an important feature. The Kachkanarsky GOK produces sinter and pellets and supplies them to the Nizhne Tagil Metallurgical Plant.

The initial base of this plant was the deposits of the Tagilo-Kushvinsky iron ore region, which have now been practically developed.

Magnitogorsk field magnetite ores, which played a huge role in the development of the Magnitogorsk Iron and Steel Works, have also been depleted due to long-term intensive exploitation.

To the south of Novokuznetsk is the Gorno-Shorsky iron ore region, formed by Temir-Tausky, Odrabashsky, Tashtagolsky and other deposits of magnetite and martite ores containing 30-49% Fe. A distinctive feature of some ores is the presence of zinc (0.1-1.1%) and high sulfur content. Reserves are estimated at 200 million tons. Ores and concentrates are sintered at processing and sintering factories, and the sinter is sent to the Novokuznetsk and West Siberian metallurgical plants. However, their main base is the Abakan and Teyskoye fields, located east of Novokuznetsk, in Khakassia. Their reserves amount to about 2 billion tons of magnetite ores.

There are a number of large iron ore deposits located in Eastern Siberia.

To the north of Krasnoyarsk in the Angara-Pitsky iron ore region there are the Nizhneangarskoye, Ishimbinskoye and other deposits. The ores of these deposits are mainly hematite, difficult to enrich, contain about 30-40% Fe, the waste rock is siliceous-alumina. The reserves of this area are about 1.4 billion tons.

North of Irkutsk there is a large Angaro-Ilimsky iron ore region, combining the Korshunovskoye, Rudnogorskoye and other deposits. Reserves are estimated at 900 million tons. The ore of these deposits is magnetite, contains 38-50% Fe, 0.03% S and 0.8% R.

Let's look at the largest foreign iron ore deposits.

The main iron ore base of ferrous metallurgy USA is the Lake Superior region, which produces about 80% of the ore mined in the country. In this area, the largest amount of ore is mined in Mesabi County, from which the ore takes its name. Mesabi ore contains 50-52% Fe, 9-10% SiO2, 0.77% Mn, 0.09% P and about 11% moisture. Ore reserves are estimated at 1 billion tons; in addition, the deposit contains about 30 billion tons of quartzites (locally called taconites), of which about 5 billion tons are magnetite. The latter are mined and enriched from 31 to 64% Fe, then subjected to agglomeration into agglomerate or pellets. This and other deposits satisfy the needs of the US iron and steel industry only partially.

A characteristic feature of the metallurgical industry of developed capitalist countries (USA, Japan, Germany, etc.) is the import of large quantities of iron ore and pellets from large deposits of the world, usually located in developing countries. The high quality of these ores, the low cost of their extraction and processing, and low transportation costs ensure the efficiency of such work. Below is a brief description of the largest iron ore regions in the world.

Canada has significant reserves of iron ore and has a developed iron ore industry - mining, enrichment and agglomeration in the form of agglomeration and pellet production. The main deposits are located in the provinces of Quebec, Newfoundland (Newfoundland Island, Wabana field), etc. The reserves of Canada's main deposits are estimated at 5.5 billion tons, of which about 3 billion tons are located in the Quebec-Labrador region. The ores of this deposit are hematites and magnetites, contain about 53% Fe, have siliceous gangue, do not contain sulfur, but contain 0.03-1.1% P. The resulting concentrate and pellets are exported to the USA, England and Germany.

Venezuela has large reserves of high-quality ores, which are estimated at 2.2 billion tons. Hematite ores, with a very high iron content (63-68%), do not contain sulfur and phosphorus. About 20 million tons of ore are mined per year, 80% of which is sent to the USA.

Brazil has huge reserves of high-quality iron ores. Reserves in the state of Minas Gerais (Itabiri, Itabirita deposits) are estimated at 16 billion tons and contain 50-60% Fe. Lump ore contains 66-69% Fe and 0.1-1.5% SiO 2, 0.5-1% Al 2 0 3.

IN Australia deposits with a reserve of about 16 billion tons of hematite and partially limonite ores have been explored. The main deposits are located in Western Australia, near the coast. The largest Brocken deposit contains about 8 billion tons of hematite and hematite-limonite ore, containing 54-69% iron. The ores mined here and the pellets produced locally are exported mainly to Japan through nearby ports.

IN India there are significant reserves of iron ore, which amount to about 20 billion tons. The main deposits are located 300 km west of Calcutta in the states of Bihar, Orissa and Madhya Pradesh, forming together the so-called Iron Belt with total reserves of 8 billion tons of rich hematite ore They contain 60-68% Fe, very pure in sulfur and phosphorus. A negative feature of these ores is the predominance of alumina in the waste rock.

Russia is a land that nature has generously endowed with such mineral wealth as iron ore. To at least roughly appreciate this luck, it is enough to imagine the role of metal objects in our lives and build a logical bridge to the categories of production.

It is not for nothing that when they first entered the lives of people hundreds of centuries ago, the changes in the way of life and consciousness of mankind turned out to be so great that this era began to be called the “Iron Age”.

What is iron ore and what does it look like?

Formations in the earth's crust containing iron in more or less pure form or its compounds with other substances: oxygen, sulfur, silicon, etc.

Such deposits are called ore when the extraction of a valuable substance on an industrial scale is economically profitable.

There are many types of such mineral formations. The species leader of the geological rock is red iron ore or hematite in Greek. The name translated from Greek means “blood-red” and has the chemical formula – Fe 2 O 3.

Iron oxide has a complex color ranging from black to cherry and red. Opaque, can be dusty and dense (in the second case it has a surface sheen).

Diverse in shape - found in the form of grains, scales, crystals and even a pink bud.

Iron Ore Formation

Based on their origin in nature, iron-containing minerals useful for humans can be classified into several main groups:

1. Magmatogenic formations are formed under the influence of high temperatures.
2. Exogenous - originated in river valleys as a result of precipitation and weathering of rocks.
3. Metamorphogenic - formed on the basis of old sedimentary deposits from high pressure and heat.

These groups are in turn divided into numerous subspecies.

Types of iron ores and their characteristics

From an economic point of view, they are classified primarily by their iron content:

1. High – more than 55%. These are not natural formations, but already an industrial semi-finished product.
2. Average. An example is sinter ore. Obtained from iron-rich natural raw materials through mechanical action.
3. Low – less than 20%. These are obtained as a result of magnetic separation.

The location of ore mining is also economically important:

1. Linear - lie in places of depressions in the earth's surface, the richest in iron, with a low content of sulfur and phosphorus.
2. Flat-like - in nature they form on the surface of iron-containing quartzites.

According to geological parameters, in addition to hematites, the following are widespread and actively used:

1. Brown iron ore (nFe 2 O 3 + nH 2 O) is a metal oxide with the participation of water, usually based on limonites. Characteristic dirty yellowish color, loose, porous. Valuable metal contains from a quarter to fifty percent. Not much - but the substance is well restored. It is enriched for further production of good cast iron.
2. Magnetic iron ore, magnetite - natural iron oxide (Fe 3 O 4). Hematite species are less common, but they contain more than 70% iron. They are dense and granular, in the form of crystals embedded in the rock, black and blue in color. Initially, the compound has magnetic properties; exposure to high temperatures neutralizes them.
3. Spar iron ore containing siderite FeCO 3.
4. There is a large proportion of clay in the ore, then it is clay iron ore. A rare species with relatively low iron content and voids.

Iron ore deposits in Russia

The largest deposit in the world is the Kursk Magnetic Anomaly. This natural creation is so grandiose that people have been trying to understand it since the end of the 16th century. Navigation instruments went crazy from the power of the electric field acting from underground over more than 150 square kilometers. Ore reserves amount to billions of tons.

Deposits of magnetite quartzites are being developed in the Olenegorsk deposit near Muromsk.

On the Kola Peninsula, magnetite, olivine, apatite and magnesioferrite are mined from the Eisko-Kovdor accumulation, and there are many mines in Karelia on the territory of the Kostomuksha deposit.

One of the oldest ore mining sites that can be found on the map of Russia is located in the Sverdlovsk region. It has been supplying material since the end of the 18th century and is called the Kachkanar group of deposits.

The legacy of the Demidov family of entrepreneurs from the Petrine era is actively being transformed. At the end of the 20th century, the Gusevogorsk ore accumulation began to be developed here.

Iron ore reserves in the world

After the grandiose accumulation near Kursk, the largest phenomenon among similar ones on the world geographical map is the strip of iron deposits of the Krivoy Rog deposit in Ukraine.

Map of iron ore deposits in the world (click to enlarge)

The wealth of the Lorraine iron ore basin is shared by three European countries - France, Luxembourg and Belgium.

In North America, large mines operate in Newfoundland, Belle Island and near Labrador City. In the South, places rich in ore were called Itabira and Karazhas.

Northeast India also has impressive ore reserves, and on the African continent it is mined in the Guinean city of Conakry.

The list of distribution by country looks like this:

Iron ore mining

The first criterion for mining methods is where the work is carried out:

1. On the ground: when fossils occur no more than half a kilometer from the surface. In this case, it is more economically profitable (and more expensive for the environment) to dig giant quarries using blasting operations and special equipment. This is an open source mining method.
2. Underground: a large immersion of ore in the bowels of the earth requires the creation of a mine. The closed mining method is not so traumatic for the ecological system, but more labor-intensive and dangerous for humans.

The extracted ore is transported to the plant, where the raw material is crushed for subsequent enrichment. Iron is drawn away from chemical compounds with other elements.

Sometimes to do this you have to go through not one, but several processes:

1. Gravity separation (ore particles, due to different physical densities, disintegrate due to mechanical effects on the material - crushing, vibration, rotation and screening).
2. Flotation (oxidation of evenly crushed raw materials with air, which attaches metal to itself).
3. Magnetic separation:
   • the impurity is washed off with a stream of water, and the metal is pulled away with a magnet - an ore concentrate is obtained;
   • the product of magnetic separation undergoes flotation - the raw material reveals another half of the iron in its pure form.
4. Complex method: using all the above processes, sometimes several times.

The resulting hot briquetted iron is sent to an electrometallurgical plant, where it takes the form of a metal billet of standard shapes or custom-made up to 12 meters. And the cast iron is sent to blast furnace production.

Iron Ore Applications

Intended use – production of cast iron and steel.

And they are used to make a great variety of different things that surround us: cars, office equipment, pipelines, dishes and machines, artistic forging and various tools.

Conclusion

Iron ore reserves are indicated on maps in the form of an isosceles triangle with a wide black base. The sign conveys the essence of the iron and steel industry: it is the stable basis of the modern manufacturing economy, which is still considered true by most financiers - in contrast to the various cryptocurrency markets.

Today it is difficult to imagine life without steel, from which many things around us are made. The basis of this metal is iron, obtained by smelting ore. Iron ore differs in origin, quality, and mining method, which determines the feasibility of its extraction. Iron ore also differs in its mineral composition, the percentage of metals and impurities, as well as the usefulness of the additives themselves.

Iron as a chemical element is included in the composition of many rocks, however, not all of them are considered raw materials for mining. It all depends on the percentage composition of the substance. Specifically, iron refers to mineral formations in which the volume of useful metal makes its extraction economically feasible.

The extraction of such raw materials began 3000 years ago, since iron made it possible to produce higher-quality durable products in comparison with copper and bronze (see). And already at that time, craftsmen who had smelters distinguished the types of ore.

Today the following types of raw materials are mined for further metal smelting:

• Titanium-magnetite;
• Apatite-magnetite;
• Magnetite;
• Magnetite-hematite;
• Goethite-hydrogoethite.

Iron ore is considered rich if it contains at least 57% iron. But developments can be considered feasible at 26%.

Iron in the rock is most often in the form of oxides, the remaining additives are silicas, sulfur and phosphorus.

All currently known types of ores were formed in three ways:

• Igneous. Such ores were formed as a result of exposure to high temperatures of magma or ancient volcanic activity, that is, the melting and mixing of other rocks. Such minerals are hard crystalline minerals with a high percentage of iron. Ore deposits of igneous origin are usually associated with old mountain-building zones, where the molten substance came close to the surface.

The process of formation of igneous rocks is as follows: the melt of various minerals (magma) is a very fluid substance, and when cracks form in places of faults, it fills them, cooling and acquiring a crystalline structure. This is how layers with magma frozen in the earth's crust were formed.

• Metamorphic. This is how sedimentary types of minerals are transformed. The process is as follows: when individual sections of the earth's crust move, some of its layers containing the necessary elements fall under the underlying rocks. At depth, they are susceptible to the high temperature and pressure of the upper layers. Over the course of millions of years of such exposure, chemical reactions occur here that transform the composition of the source material and crystallize the substance. Then, during the next movement, the rocks end up closer to the surface.

Typically, iron ore of this origin does not lie too deep and has a high percentage of useful metal composition. For example, a bright example is magnetic iron ore (up to 73-75% iron).

• Sedimentary. The main “workers” in the process of ore formation are water and wind. Destroying rock layers and moving them to lowlands, where they accumulate in the form of layers. Plus, water, as a reagent, can modify the source material (leach). As a result, brown iron ore is formed - crumbly and friable ore containing from 30% to 40% iron, with a large number of various impurities.

Due to various ways of formation, raw materials are often mixed in layers with clays, limestones and igneous rocks. Sometimes deposits of different origins can be mixed in one field. But most often one of the listed breed types predominates.

Having established through geological exploration an approximate picture of the processes occurring in a particular area, possible locations with iron ores are determined. Like, for example, the Kursk magnetic anomaly, or the Krivoy Rog basin, where industrially valuable types of iron ore were formed as a result of magmatic and metamorphic influences.

Extraction of iron ore on an industrial scale

Humanity began to mine ore a very long time ago, but most often it was low-quality raw material with significant sulfur impurities (sedimentary rocks, the so-called “swamp” iron). The scale of development and smelting was constantly increasing. Today, a whole classification of various deposits of ferrous ores has been built.

Main types of industrial deposits

All ore deposits are divided into types depending on the origin of the rock, which in turn makes it possible to distinguish main and secondary iron ore areas.

Main types of industrial iron ore deposits

These include the following deposits:

• Deposits of various types of iron ore (ferruginous quartzites, magnetic iron ore), formed by a metamorphic method, which makes it possible to mine ores that are very rich in composition. Typically, deposits are associated with ancient processes of formation of rocks in the earth's crust and lie on formations called shields.

A crystalline shield is a formation shaped like a large curved lens. It consists of rocks formed during the formation of the earth's crust 4.5 billion years ago.

The most famous deposits of this type are: Kursk Magnetic Anomaly, Krivoy Rog Basin, Lake Superior (USA/Canada), Hamersley Province in Australia, and the Minas Gerais iron ore region in Brazil.

• Deposits of stratified sedimentary rocks. These deposits were formed due to the sedimentation of iron-rich compounds that are present in minerals destroyed by wind and water. A striking example of iron ore in such deposits is brown iron ore.

The most famous and large deposits are the Lorraine basin in France and the Kerch basin on the peninsula of the same name (Russia).

• Skarn deposits. Usually the ore is of igneous and metamorphic origin, the layers of which, after formation, were displaced at the time of formation of the mountains. That is, iron ore, located in layers at depth, was crushed into folds and moved to the surface during the movement of lithospheric plates. Such deposits are often located in folded areas in the form of layers or pillars of irregular shape. Formed magmatically. Representatives of such deposits: Magnitogorskoye (Ural, Russia), Sarbaiskoye (Kazakhstan), Iron Springs (USA) and others.
• Titanium magnetite ore deposits. Their origin is igneous, most often found on outcrops of ancient bedrock - shields. These include basins and fields in Norway, Canada, Russia (Kachkanarskoye, Kusinskoye).

Secondary deposits include: apatite-magnetite, magno-magnetite, siderite, ferromanganese deposits developed in Russia, European countries, Cuba and others.

Iron ore reserves in the world - leading countries

Today, according to various estimates, deposits with a total volume of 160 billion tons of ore have been explored, from which about 80 billion tons of metal can be obtained.

The US Geological Survey presents data according to which Russia and Brazil account for about 18% of the world's iron ore reserves.

In terms of iron reserves, the following leading countries can be identified:

The picture of world ore reserves looks like this:

Most of these countries are also the largest exporters of iron ore. In general, the volume of raw materials sold is about 960 million tons per year. The largest importers are Japan, China, Germany, South Korea, Taiwan, France.

Typically, private companies are involved in the extraction and sale of raw materials. For example, the largest in our country are Metallinvest and Evrazholding, producing a total of about 100 million tons of iron ore products.

According to estimates by the same US Geological Survey, mining and production volumes are constantly growing, about 2.5-3 billion tons of ore are mined per year, which reduces its value on the world market.

The markup on 1 ton today is approximately $40. The record price was recorded in 2007 – $180/ton.

How is iron ore mined?

Iron ore layers lie at different depths, which determines how it is extracted from the subsoil.

Career way. The most common method of quarrying is used when deposits are found at a depth of about 200-300 meters. Development occurs through the use of powerful excavators and rock crushing plants. After which it is loaded for transportation to processing plants.

Mine method. The mine method is used for deeper layers (600-900 meters). Initially, a mine alignment is pierced, from which drifts are developed along the layers. From where the crushed rock is supplied “to the mountain” using conveyors. Ore from the mines is also sent to processing plants.

Borehole hydraulic production. First of all, for borehole hydraulic mining, a well is drilled to the rock layer. After that, pipes are brought into the target, and the ore is crushed with powerful water pressure for further extraction. But this method today has very low efficiency and is used quite rarely. For example, 3% of raw materials are extracted using this method, and 70% using the mine method.

After extraction, iron ore material must be processed to obtain the main raw material for metal smelting.

Since the composition of ores, in addition to the necessary iron, contains many impurities, in order to obtain the maximum useful yield it is necessary to purify the rock by preparing the material (concentrate) for smelting. The entire process is carried out at mining and processing plants. Different types of ores have their own methods and methods of purification and removal of unnecessary impurities.

For example, the technological chain for the enrichment of magnetic iron ores is as follows:

• Initially, the ore goes through the crushing stage in crushing plants (for example, jaw crushers) and is fed by a conveyor belt to a separation station.
• Using electromagnetic separators, parts of magnetic iron ore are separated from waste waste rock.
• After which the ore mass is transported for further crushing.
• The crushed minerals are moved to the next cleaning station, the so-called vibrating sieves, where the useful ore is sieved, separating it from the light waste rock.
• The next stage is a fine ore hopper, in which small particles of impurities are separated by vibration.
• Subsequent cycles include the next addition of water, grinding and passing the ore mass through slurry pumps, which remove unnecessary sludge (waste rock) along with the liquid, and again crushing.
• After repeated purification by pumps, the ore goes to the so-called screen, which once again purifies the minerals using the gravitational method.
• The repeatedly purified mixture is fed to a dehydrator, which removes water.
• The dried ore again goes to magnetic separators, and only then to the gas-liquid station.

Brown iron ore is purified according to slightly different principles, but the essence does not change, because the main task of beneficiation is to obtain the purest raw materials for production.

The result of enrichment is iron ore concentrate, which is used in smelting.

What is made from iron ore - uses of iron ore

It is clear that iron ore is used to obtain metal. But two thousand years ago, metallurgists realized that in its pure form, iron is a rather soft material, products from which are slightly better than bronze. The result was the discovery of an alloy of iron and carbon - steel.

Carbon for steel plays the role of cement, strengthening the material. Typically, such an alloy contains from 0.1 to 2.14% carbon, and above 0.6% is already high-carbon steel.

Today, a huge list of products, equipment and machines are made from this metal. However, the invention of steel was associated with the development of gunsmithing, craftsmen in which tried to obtain a material with durable characteristics, but at the same time, with excellent flexibility, malleability, and other technical, physical and chemical characteristics. Today, high-quality metal also has other additives that alloy it, adding hardness and wear resistance.

The second material that is produced from iron ore is cast iron. It is also an alloy of iron and carbon, which contains more than 2.14%.

For a long time, cast iron was considered a useless material, which was obtained either when steel smelting technology was violated, or as a by-product metal settling at the bottom of smelting furnaces. It was mostly thrown away and cannot be forged (it is brittle and practically not ductile).

Before the advent of artillery, they tried to add cast iron to the household in various ways. For example, in construction, foundation blocks were made from it, coffins were made in India, and in China, initially, coins were even minted. The advent of cannons made it possible to use cast iron for casting cannonballs.

Today, cast iron is used in many industries, especially in mechanical engineering. This metal is also used to produce steel (open hearth furnaces and the Bessmer method).

As production increases, more and more materials are required, which contributes to intensive mining. But developed countries consider it more expedient to import relatively inexpensive raw materials, reducing the volume of their own production. This allows the main exporting countries to increase the production of iron ore with its further enrichment and sale as concentrate.