How is iron (steel) obtained and from what is it made? About iron - in simple and accessible language How to get steel from ore.

Technology of iron production in ancient times

To obtain iron from ore, you first need to get kritsa. For this, oxidized iron ore, which most often occurs near the surface, was first used. After the discovery of its properties, such deposits were quickly depleted as a result of their intensive development.

Swamp ores are much more widespread. They were formed in the sub-Atlantic period, when, during the process of swamping, iron ore settled to the bottom of reservoirs. Throughout the Middle Ages, ferrous metallurgy used bog ores. They even paid duties with them. The production of iron from ore in relatively large quantities became possible after the invention of the cheese furnace. This name appeared after the invention of heated air blast in blast furnaces. In ancient times, metallurgists fed raw (cold) air into the forge. At a temperature of 900 o using carbon dioxide, which takes away oxygen from iron oxide, iron is reduced from the ore and a dough or shapeless, porous piece soaked in slag is obtained - kritsa. To carry out this process, charcoal was needed as a source of carbon dioxide. The kritsa was then forged in order to remove the slag from it. The cheese-making method, sometimes called iron smelting, is uneconomical, but for a long time it remained the only and unchanged method of obtaining ferrous metal.

At first, iron was smelted in ordinary pits, closed at the top; later, clay furnaces began to be built. Crushed ore and coal were loaded into the working space of the forge in layers, all this was set on fire, and air was forced through the nozzle holes with special (leather) bellows. The rock settles into slag at a temperature of 1300-1400 o, at which steel is obtained - iron containing from 0.3 to 1.2%. carbon. As it cools, it becomes very hard. To obtain cast iron - fusible iron with a carbon content of 1.5-5% - you need a more complex forge design with a large working space. In this case, the melting point of iron was lower, and it partially flowed out of the furnace along with the slag. When it cooled, it became fragile, and at first it was thrown away, but then they learned to use it. To make malleable iron from cast iron, you need to remove carbon from it.

Technology for creating iron alloys

The first device for obtaining iron from ore was a disposable cheese furnace. With a huge number of disadvantages, for a long time this was the only way to obtain metal from ore.

Ancient people lived richly and happily for a long time - stone axes were made from jasper, and malachite was burned to obtain copper, but all good things tend to come to an end. One of the reasons for the collapse of the ancient civilization of the Mediterranean was the depletion of mineral resources. Gold ran out not in the treasury, but in the depths; tin ran out even on the “Tin Islands.” Although copper is still mined in Sinai and Cyprus, the deposits that are being developed now were not available to the Romans. Among other things, the ore suitable for cheese processing has also run out. There was still a lot of lead.

However, the barbarian tribes that settled Europe, which had become ownerless, did not know for a long time that its mineral resources had been depleted by their predecessors. Given the huge drop in metal production, the resources that the Romans disdained were sufficient for a long time. Later, metallurgy began to revive primarily in Germany and the Czech Republic - that is, where the Romans did not reach with picks and wheelbarrows.

A higher stage in the development of ferrous metallurgy was represented by permanent high furnaces called stucco ovens in Europe. It really was a tall stove - with a four-meter pipe to enhance traction. The bellows of the stucco machine were already swinging by several people, and sometimes by a water engine. The Stukofen had doors through which the kritsa was removed once a day.

Stukofens were invented in India at the beginning of the first millennium BC. At the beginning of our era, they came to China, and in the 7th century, along with “Arabic” numerals, the Arabs borrowed this technology from India. At the end of the 13th century, Stuktofens began to appear in Germany and the Czech Republic (and even before that they were in southern Spain) and over the next century they spread throughout Europe.

The productivity of the stukofen was incomparably higher than that of a cheese-blowing furnace - it produced up to 250 kg of iron per day, and the melting temperature in it was sufficient to carburize part of the iron to the state of cast iron. However, when the furnace was stopped, plaster cast iron froze at its bottom, mixing with slag, and at that time they could only clean metal from slag by forging, but cast iron did not lend itself to this. He had to be thrown away.

Sometimes, however, they tried to find some use for plaster cast iron. For example, the ancient Hindus cast coffins from dirty cast iron, and the Turks at the beginning of the 19th century cast cannonballs. It’s hard to judge how coffins are, but the cannonballs that came out of it were just so-so.

Cannonballs for cannons were cast from ferrous slag in Europe at the end of the 16th century. Roads were made from cast paving stones. In Nizhny Tagil, buildings with foundations made of cast slag blocks are still preserved.

Metallurgists have long noticed a connection between the melting temperature and the yield of the product - the higher it was, the larger part of the iron contained in the ore could be recovered. Therefore, sooner or later the idea came to them to speed up the stukofen by preheating the air and increasing the height of the pipe. In the middle of the 15th century, a new type of furnace appeared in Europe - blauofen, which immediately gave steelmakers an unpleasant surprise.

The higher melting temperature did indeed significantly increase the yield of iron from the ore, but it also increased the proportion of iron that was carburized to the state of cast iron. Now, not 10%, as in the stucco machine, but 30% of the output was cast iron - “pork iron”, not suitable for any purpose. As a result, the gains often did not pay for the modernization.

Blauofen cast iron, like stucco cast iron, solidified at the bottom of the furnace, mixing with slag. It turned out somewhat better, since there was more of it, therefore, the relative content of slag was less, but it continued to remain unsuitable for casting. The cast iron obtained from blauofen turned out to be quite strong, but still remained very heterogeneous - only simple and rough objects came out of it - sledgehammers, anvils. There were already quite a few cannonballs coming out.

In addition, if in cheese furnaces only iron could be obtained, which was then carburized, then in stukofen and blauofen the outer layers of kritsa turned out to be made of steel. There was even more steel in the blauofen krits than iron. On the one hand, this seemed good, but it turned out to be very difficult to separate steel and iron. The carbon content was becoming difficult to control. Only long forging could achieve uniformity of its distribution.

At one time, faced with these difficulties, the Indians did not move further, but began to refine the technology and came to the production of damask steel. But Indians at that time were not interested in the quantity, but in the quality of the product. Europeans, experimenting with cast iron, soon discovered a conversion process that raised iron metallurgy to a qualitatively new level.

The next stage in the development of metallurgy was the appearance of blast furnaces. By increasing the size, preheating the air and mechanical blasting, in such a furnace all the iron from ore was converted into cast iron, which was melted and periodically released outside. Production became continuous - the furnace worked around the clock and did not cool down. It produced up to one and a half tons of cast iron per day. Distilling cast iron into iron in forges was much easier than beating it out of the kritsa, although forging was still required - but now they were beating slag out of iron, and not iron out of slag.

Blast furnaces were first used at the turn of the 15th-16th centuries in Europe. In the Middle East and India, this technology appeared only in the 19th century (to a large extent, probably because the water engine was not used due to the characteristic water shortage in the Middle East). The presence of blast furnaces in Europe allowed it to overtake Turkey in the 16th century, if not in the quality of the metal, then in the shaft. This had an undoubted influence on the outcome of the struggle, especially when it turned out that cannons could be cast from cast iron.

WITH early XVII century, Sweden became the European forge, producing half of the iron in Europe. In the middle of the 18th century, its role in this regard began to rapidly decline due to another invention - its use in metallurgy coal.

First of all, it must be said that until the 18th century inclusive, coal was practically not used in metallurgy - due to the high content of impurities harmful to the quality of the product, primarily sulfur. Since the 17th century in England, coal began to be used in puddling furnaces for annealing cast iron, but this made it possible to achieve only a small saving on charcoal - most of fuel was spent on smelting, where it was impossible to exclude contact of coal with ore.

Among the many metallurgical professions of that time, perhaps the most difficult profession was that of a puddler. Pudding was the main method of obtaining iron throughout almost the entire 19th century. It was a very difficult and time-consuming process. The work under him went like this: Pig iron was loaded onto the bottom of the fiery furnace; they were melted down. As carbon and other impurities burned out of the metal, the melting temperature of the metal increased and crystals of fairly pure iron began to “freeze out” from the liquid melt. A lump of sticky dough-like mass collected at the bottom of the oven. The puddling workers began the operation of rolling the dough using an iron scrap. Mixing the mass of metal with a crowbar, they tried to collect a lump, or kritsa, of iron around the crowbar. Such a lump weighed up to 50 - 80 kg or more. The kritsa was pulled out of the furnace and fed directly under the hammer - for forging in order to remove slag particles and compact the metal.

They learned to eliminate sulfur by coking in England in 1735, after which it became possible to use large reserves of coal for smelting iron. But outside of England, this technology spread only in the 19th century.

Fuel consumption in metallurgy was already enormous even then - the blast furnace devoured a carload of coal per hour. Charcoal has become a strategic resource. It was the abundance of wood in Sweden itself and its Finland that allowed the Swedes to develop production on such a scale. The English, who had fewer forests (and even those were reserved for the needs of the fleet), were forced to buy iron in Sweden until they learned to use coal.

Electric and induction methods of iron smelting

The variety of steel compositions makes their smelting very difficult. After all, in an open-hearth furnace and converter the atmosphere is oxidizing, and elements such as chromium easily oxidize and turn into slag, i.e. are lost. This means that in order to obtain steel with a chromium content of 18%, much more chromium must be fed into the furnace than 180 kg per ton of steel. And chromium is an expensive metal. How to find a way out of this situation?

A solution was found at the beginning of the 20th century. It was proposed to use the heat of an electric arc to smelt metal. Scrap metal was loaded into a circular furnace, cast iron was poured in, and carbon or graphite electrodes were lowered. An electric arc with a temperature of about 4000°C arose between them and the metal in the furnace (“bath”). The metal melted easily and quickly. And in such a closed electric furnace you can create any atmosphere - oxidizing, reducing or completely neutral. In other words, valuable elements can be prevented from burning out. This is how the metallurgy of high-quality steels was created.

Later, another method of electric melting was proposed - induction. It is known from physics that if a metal conductor is placed in a coil through which a high-frequency current passes, a current is induced in it and the conductor heats up. This heat is enough to certain time melt the metal. An induction furnace consists of a crucible with a spiral embedded in its lining. A high-frequency current is passed through the spiral, and the metal in the crucible melts. In such a stove you can also create any atmosphere.

In electric arc furnaces, the smelting process usually occurs in several stages. First, unnecessary impurities are burned out of the metal, oxidizing them (oxidation period). Then the slag containing the oxides of these elements is removed (downloaded) from the furnace, and ferroalloys - iron alloys with elements that need to be introduced into the metal - are loaded. The furnace is closed and melting continues without air access (recovery period). As a result, the steel is saturated with the required elements in a given quantity. The finished metal is released into a ladle and poured.

Chemical reactions in the production of iron

In modern industry, iron is obtained from iron ore, mainly from hematite (Fe 2 O 3) and magnetite (Fe 3 O 4).

Exist various ways extraction of iron from ores. The most common is the domain process.

The first stage of production is the reduction of iron with carbon in a blast furnace at a temperature of 2000 °C. In a blast furnace, carbon in the form of coke, iron ore in the form of agglomerate or pellets, and flux (such as limestone) are fed from above, and are met by a stream of forced hot air from below.

In the furnace, the carbon in the coke is oxidized to carbon monoxide (carbon monoxide) by atmospheric oxygen:

2C + O 2 → 2CO.

In turn, carbon monoxide reduces iron from the ore:

3CO + Fe 2 O 3 → 2Fe + 3CO 2.

Flux is added to extract unwanted impurities from the ore, primarily silicates such as quartz (silicon dioxide). A typical flux contains limestone (calcium carbonate) and dolomite (magnesium carbonate). Other fluxes are used against other impurities.

Effect of flux: calcium carbonate decomposes under the influence of heat to calcium oxide (quicklime):

CaCO 3 → CaO + CO 2 .

Calcium oxide combines with silicon dioxide to form slag:

CaO + SiO 2 → CaSiO 3.

Slag, unlike silicon dioxide, is melted in a furnace. Slag, lighter than iron, floats on the surface and can be drained separately from the metal. The slag is then used in construction and agriculture. The molten iron produced in a blast furnace contains quite a lot of carbon (cast iron). Except in cases where cast iron is used directly, it requires further processing.

Excess carbon and other impurities (sulfur, phosphorus) are removed from cast iron by oxidation in open-hearth furnaces or converters. Electric furnaces are also used for smelting alloy steels.

In addition to the blast furnace process, the process of direct iron production is common. In this case, pre-crushed ore is mixed with special clay, forming pellets. The pellets are fired and treated in a shaft furnace with hot methane conversion products containing hydrogen. Hydrogen easily reduces iron without contaminating the iron with impurities such as sulfur and phosphorus - common impurities in coal. Iron is obtained in solid form and is subsequently melted in electric furnaces.

Chemically pure iron is obtained by electrolysis of solutions of its salts.

Part 1. Why is all this necessary?

If we're talking about about creating a replica of a historical artifact (for example, a knife or ax of the 10th century), then the master faces at least 3 tasks:

1. Repeat the appearance. In other words, create a mass-dimensional model. An example of a replica of an ax from the Jakštaicai burial ground, Lithuania. The ax is made in compliance with the dimensions of the original.

By appearance medieval weapons were studied by such famous authors as Edward Oakeshott, Jan Petersen, Anatoly Kirpichnikov.

2. Structure of the forged product. Most medieval artifacts are made, in modern terms, from at least two different brands steels Here we are talking about the technology of forge welding, the technology of manufacturing Damascus steel. Due to the high cost carbon steel In the Middle Ages, technology was widely used when only the working part of the product (for example, in a knife, this blade) was steel, and everything else was made of iron or low-quality steel.

This topic is discussed in more detail in practice using an example . The structure of medieval forged products can be judged from books such as “Damascus Steel in the Basin Countries” Baltic Sea» Antain A.K. And " Blacksmithing Polotsk land. IX–XIII centuries.” Gurin, M.F.

3. Actually metal. Steel of the 10th century and steel of the 21st century are two fundamentally different methods of obtaining the material. And as a result, the properties of these materials differ. Probably because of these differences, this direction has become widespread in blacksmithing like Damascus steel. Ax made of raw iron.

The main method of obtaining iron in the Middle Ages was smelting swamp ore in cheese furnaces. The essence of the cheese-blowing process is that the air for fuel combustion is supplied unheated, at atmospheric parameters.

The design of medieval furnaces is described in Boris Kolchin’s book “Ferrous metallurgy and metalworking in Ancient Rus'”.

Part 2. Raw materials and preparation for smelting.

Swamp ore is brown iron ore, or limonite. The main thing it consists of is Fe2O3. This is what it looks like in nature.

The ore is reduced to pure metal using charcoal. Before smelting, the ore is enriched by washing to remove excess rock.

I did the first smelting of ore in a graphite-chamotte crucible in a gas furnace chamber. From 400 grams of ore, 160 grams of iron were obtained. The ingot is porous, the pores are clean without non-metallic inclusions.

A spectral analysis of this ingot was made for alloying elements and impurities.

The analysis showed a carbon content of 0.14%. Carbon probably entered iron from charcoal, due to the process of surface cementation. Probably, the long-term presence of an iron ingot in the area high temperatures ensured good diffusion of carbon, and as a result, its uniform distribution throughout the entire volume of the sample. Thus we can talk about obtaining low-carbon steel. The high content of phosphorus and sulfur (1.49% and 0.075%, respectively) significantly reduces the quality of the metal both from the point of view of forging processing and from the point of view of the operation of future products. To reduce the content of sulfur and phosphorus in the composition of the charge (Batch is a mixture of materials loaded into a smelting furnace to obtain a metal of a certain composition), calcium oxide CaO (quicklime) should be added. For example, add chalk CaCO3. At high temperatures (1000-1100 °C), chalk inside the forge will become quicklime.

Part 3. Ore smelting in authentic cheese furnaces.

22-23.07.2017 at museum complex"Dudutki" at the festival of the glory of Belarusian weapons "Our Grunwald-2017" ore was smelted in cheese furnaces. The purpose of this experiment is to obtain practical answers to the following questions:

1. Materials and design of cheese furnaces.

2. Method of supplying air for fuel combustion. Blowing modes.

3. Composition of the charge.

4. Slag formation and its effect on the smelting process.

5. Obtaining pure metal.

6. Metal production best quality than during the first melting in a crucible.

Looking ahead, I can say that all the assigned tasks were solved. 2 cheese furnaces were made from different materials, different designs and size. One of the two forges was made from local raw materials, the air was supplied by two-chamber bellows.

Building forges, drying them, heating them and then melting them is a very labor-intensive task. The whole process took 2 days, the work was carried out from early morning until late at night, taking into account the fact that a whole team of assistants helped me. The experiment was successful - the resulting metal is approximately 7 times cleaner in terms of harmful impurities compared to crucible melting. However, there was not much metal left. The main volume is small metal balls in pieces of slag.

Probably, if you create a higher temperature in the forge and increase the melting time, then these balls will be welded together and form a kritsa suitable for forging. Spectral analysis did not determine the carbon content, probably due to its uneven distribution in the ingot. This probably also indirectly indicates the need to increase the melting time. The experiment showed that the main parameters were generally chosen correctly, which means their optimization will lead to an improvement in the result. I will write about this later, as events develop.

Known to mankind was of cosmic origin, or, more precisely, meteorite. It began to be used as an instrumental material approximately 4 thousand years BC. The technology of metal smelting appeared several times and was lost as a result of wars and unrest, but, according to historians, the Hittites were the first to master smelting.

It is worth noting that we are talking about alloys of iron with a small amount impurities. It became possible to obtain chemically pure metal only with the advent of modern technologies. This article will tell you in detail about the features of metal production by direct reduction, flash, sponge, raw material, hot briquetted iron, and we will touch on the production of chlorine and pure substances.

First, it’s worth considering the method of producing iron from iron ore. Iron is a very common element. In terms of content in the earth's crust, the metal ranks 4th among all elements and 2nd among metals. In the lithosphere, iron is usually presented in the form of silicates. Its highest content is observed in basic and ultrabasic rocks.

Almost all mining ores contain some amount of iron. However, only those rocks in which the proportion of the element is of industrial importance are developed. But even in this case, the amount of minerals suitable for development is more than large.

• First of all, this iron ore– red (hematite), magnetic (magnetite) and brown (limonite). These are complex iron oxides with an element content of 70–74%. Brown iron ore is more often found in weathering crusts, where it forms so-called “iron hats” up to several hundred meters thick. The rest are mainly of sedimentary origin.
• Very common iron sulfide– pyrite or sulfur pyrite, but it is not considered iron ore and is used for the production of sulfuric acid.
• Siderite– iron carbonate, includes up to 35%, this ore is medium in element content.
• Marcasite– includes up to 46.6%.
• Mispickel– a compound with arsenic and sulfur, contains up to 34.3% iron.
• Lellingit– contains only 27.2% of the element and is considered a low-grade ore.

Mineral rocks are classified according to their iron content as follows:

• rich– with a metal content of more than 57%, with a silica content of less than 8–10%, and an admixture of sulfur and phosphorus of less than 0.15%. Such ores are not enriched and are immediately sent to production;
• medium grade ore includes at least 35% of the substance and needs to be enriched;
• poor iron ores must contain at least 26%, and are also enriched before being sent to the workshop.

The general technological cycle of iron production in the form of cast iron, steel and rolled products is discussed in this video:

Mining

There are several methods for extracting ore. The one that is found most economically feasible is used.

• Open development method- or career. Designed for shallow mineral rock. For mining, a quarry is dug to a depth of up to 500 m and a width depending on the thickness of the deposit. Iron ore is extracted from the quarry and transported by vehicles designed to carry heavy loads. As a rule, this is how high-grade ore is mined, so there is no need to enrich it.
• Shakhtny– when the rock occurs at a depth of 600–900 m, mines are drilled. Such development is much more dangerous because it involves underground blasting: the discovered layers are blasted, and then the collected ore is transported upward. Despite its dangers, this method is considered more effective.
• Hydro production– in this case, wells are drilled to a certain depth. Pipes are lowered into the mine and water is supplied under very high pressure. The water jet crushes the rock, and then the iron ore is lifted to the surface. Borehole hydraulic production is not widespread, as it requires high costs.

Iron production technologies

All metals and alloys are divided into non-ferrous (like, etc.) and ferrous. The latter include cast iron and steel. 95% of all metallurgical processes occur in ferrous metallurgy.

Despite the incredible variety of steels produced, there are not so many manufacturing technologies. In addition, cast iron and steel are not exactly 2 different products; cast iron is a mandatory preliminary stage in the production of steel.

Product classification

Both cast iron and steel are classified as iron alloys, where the alloying component is carbon. Its share is small, but it gives the metal very high hardness and some brittleness. Cast iron, because it contains more carbon, is more brittle than steel. Less plastic, but has better heat capacity and resistance to internal pressure.

Cast iron is produced by blast furnace smelting. There are 3 types:

• gray or cast– obtained by slow cooling method. The alloy contains from 1.7 to 4.2% carbon. Gray cast iron can be easily processed with mechanical tools and fills molds well, which is why it is used for the production of castings;
• white– or conversion, obtained by rapid cooling. The share of carbon is up to 4.5%. May include additional impurities, graphite, manganese. White cast iron is hard and brittle and is mainly used for making steel;
• malleable– includes from 2 to 2.2% carbon. Produced from white cast iron by long-term heating of castings and slow, long-term cooling.

Steel can contain no more than 2% carbon; it is produced in 3 main ways. But in any case, the essence of steelmaking comes down to annealing unwanted impurities of silicon, manganese, sulfur, and so on. In addition, if alloy steel is produced, additional ingredients are introduced during the manufacturing process.

According to purpose, steel is divided into 4 groups:

• construction– used in the form of rental without heat treatment. This is a material for the construction of bridges, frames, the manufacture of carriages, and so on;
• mechanical engineering– structural, belongs to the category of carbon steel, contains no more than 0.75% carbon and no more than 1.1% manganese. Used to produce a variety of machine parts;
• instrumental– also carbon, but with a low manganese content – ​​no more than 0.4%. It is used to produce a variety of tools, in particular metal-cutting ones;
• steel special purpose – this group includes all alloys with special properties: heat-resistant steel, stainless steel, acid-resistant and so on.

Preliminary stage

Even rich ore must be prepared before smelting iron - freed from waste rock.

• Agglomeration method– the ore is crushed, ground and poured along with coke onto the belt of the sintering machine. The tape passes through burners, where the temperature ignites the coke. In this case, the ore is sintered, and sulfur and other impurities burn out. The resulting agglomerate is fed into bunker bowls, where it is cooled with water and blown with an air stream.
• Magnetic separation method– the ore is crushed and fed to a magnetic separator, since iron has the ability to be magnetized, minerals, when washed with water, remain in the separator, and waste rock is washed away. Then the resulting concentrate is used to make pellets and hot briquetted iron. The latter can be used to prepare steel, bypassing the stage of producing cast iron.

This video will tell you in detail about the production of iron:

Iron smelting

Pig iron is smelted from ore in a blast furnace:

• prepare the charge - sinter, pellets, coke, limestone, dolomite, etc. The composition depends on the type of cast iron;
• The charge is loaded into the blast furnace using a skip hoist. The temperature in the oven is 1600 C, hot air is supplied from below;
• At this temperature, iron begins to melt and coke begins to burn. In this case, iron is reduced: first, carbon monoxide is produced when coal is burned. Carbon monoxide reacts with iron oxide to produce pure metal and carbon dioxide;
• flux - limestone, dolomite, is added to the charge to convert unwanted impurities into a form that is easier to eliminate. For example, silicon oxides do not melt at such low temperatures and it is impossible to separate them from iron. But when interacting with calcium oxide obtained by the decomposition of limestone, quartz turns into calcium silicate. The latter melts at this temperature. It is lighter than cast iron and remains floating on the surface. Separating it is quite simple - the slag is periodically released through tap holes;
• Liquid iron and slag flow through different channels into ladles.

The resulting cast iron is transported in ladles to a steelmaking shop or to a casting machine, where cast iron ingots are obtained.

Steelmaking

Turning cast iron into steel is done in 3 ways. During the smelting process, excess carbon and unwanted impurities are burned off, and necessary components are also added - when welding special steels, for example.

• Open hearth is the most popular production method, as it provides high quality steel. Molten or solid cast iron with the addition of ore or scrap is fed into an open-hearth furnace and melted. The temperature is about 2000 C, maintained by the combustion of gaseous fuel. The essence of the process comes down to burning carbon and other impurities from iron. The necessary additives, when it comes to alloy steel, are added at the end of smelting. The finished product is poured into ladles or into ingots into molds.

• Oxygen-envelope method - or Bessemer. Differs more high performance. The technology involves blowing compressed air through the thickness of cast iron at a pressure of 26 kg/sq. cm. In this case, the carbon burns, and the cast iron becomes steel. The reaction is exothermic, so the temperature rises to 1600 C. To improve product quality, a mixture of air and oxygen or even pure oxygen is blown through the cast iron.
• The electric melting method is considered the most effective. Most often it is used to produce multi-alloy steels, since the smelting technology in this case eliminates the ingress of unnecessary impurities from air or gas. The maximum temperature in the iron production furnace is about 2200 C due to the electric arc.

Direct Receipt

Since 1970, the method of direct reduction of iron has also been used. The method allows you to bypass the costly stage of producing cast iron in the presence of coke. The first installations of this kind were not very productive, but today the method has become quite well known: it turned out that natural gas can be used as a reducing agent.

The raw materials for recovery are pellets. They are loaded into a shaft furnace, heated and purged with a gas conversion product - carbon monoxide, ammonia, but mainly hydrogen. The reaction occurs at a temperature of 1000 C, with hydrogen reducing iron from the oxide.

We will talk about manufacturers of traditional (not chlorine, etc.) iron in the world below.

Famous manufacturers

The largest share of iron ore deposits is in Russia and Brazil – 18%, Australia – 14%, and Ukraine – 11%. The largest exporters are Australia, Brazil and India. The peak price of iron was observed in 2011, when a ton of metal was estimated at $180. By 2016 the price had dropped to $35 per ton.

The largest iron producers include the following companies:

• Vale S.A. is a Brazilian mining company, the largest producer of iron and;
• BHP Billiton is an Australian company. Its main direction is oil and gas production. But at the same time she is largest supplier copper and iron;
• Rio Tinto Group is an Australian-British concern. Rio Tinto Group mines and produces gold, iron, diamonds and uranium;
• Fortescue Metals Group is another Australian company specializing in ore mining and iron production;
• In Russia largest producer Evrazholding is a metallurgical and mining company. Also known on the world market are Metallinvest and MMK;
• Metinvest Holding LLC is a Ukrainian mining and metallurgical company.

The prevalence of iron is great, the extraction method is quite simple, and ultimately smelting is an economically profitable process. Together with physical characteristics production and provides iron with the role of the main structural material.

The production of ferric chloride is shown in this video:

It rarely happens that I visit the same production twice. But when I was called again to Lebedinsky GOK and OEMK, I decided that I needed to take advantage of the moment. It was interesting to see what has changed in 4 years since the last trip, besides, this time I was more equipped and in addition to the camera, I also took with me a 4K camera in order to really convey to you the whole atmosphere, scorching and eye-catching shots from the mining and processing plant and steel foundries of the Oskol Electrometallurgical Plant.

Today, especially for reporting on the extraction of iron ore, its processing, smelting and production of steel products.

Lebedinsky GOK is the largest Russian enterprise for the extraction and beneficiation of iron ore and has the largest iron ore mine in the world. The plant and quarry are located in the Belgorod region, near the city of Gubkin. The company is part of the Metalloinvest company and is a leading manufacturer of iron ore products in Russia.

The view from the observation deck at the entrance to the quarry is mesmerizing.

It is really huge and growing every day. The depth of the Lebedinsky GOK pit is 250 m from sea level or 450 m from the surface of the earth (and the diameter is 4 by 5 kilometers), groundwater constantly seeps into it, and if it were not for the work of the pumps, it would fill to the very top in a month. It is twice listed in the Guinness Book of Records as the largest quarry for the extraction of non-combustible minerals.

This is how it looks from the height of the spy satellite.

In addition to the Lebedinsky GOK, Metalloinvest also includes the Mikhailovsky GOK, which is located in the Kursk region. Together, the two largest plants make the company one of the world leaders in the mining and processing of iron ore in Russia, and one of the top 5 in the world in the production of commercial iron ore. The total proven reserves of these plants are estimated at 14.2 billion tons according to the international classification JORС, which guarantees about 150 years of operational life at the current level of production. So miners and their children will be provided with work for a long time.

The weather this time was also not sunny, it was even drizzling in places, which was not in the plans, but that made the photos even more contrasting).

It is noteworthy that right in the “heart” of the quarry there is an area with waste rock, around which all the ore containing iron has already been mined. Over the past 4 years it has noticeably decreased, because this interferes further development career and it is being systematically developed too.

Iron ore is loaded immediately into railway trains, into special reinforced cars that transport the ore from the quarry, they are called dump cars, their carrying capacity is 120 tons.

Geological layers from which one can study the history of the Earth's development.

By the way, the upper layers of the quarry, consisting of rocks that do not contain iron, do not go into the dump, but are processed into crushed stone, which is then used as building material.

From the top of the observation deck, the giant machines seem no bigger than an ant.

By this railway, which connects the quarry with the plants, the ore is transported for further processing. The story will be about this later.

There are a lot of different types of equipment at work in the quarry, but the most noticeable, of course, are the multi-ton Belaz and Caterpillar dump trucks.

By the way, these giants have the same license plates as regular passenger cars and are registered with the traffic police.

Each year, both mining and processing plants included in Metalloinvest (Lebedinsky and Mikhailovsky GOK) produce about 40 million tons of iron ore in the form of concentrate and sinter ore (this is not the volume of production, but enriched ore, that is, separated from waste rock). Thus, it turns out that on average about 110 thousand tons of enriched iron ore are produced per day at the two mining and processing plants.

This Belaz transports up to 220 tons of iron ore at a time.

The excavator gives a signal and he carefully reverses. Just a few buckets and the giant’s body is filled. The excavator gives the signal again and the dump truck drives off.
This Hitachi excavator, which is the largest in the quarry, has a bucket capacity of 23 cubic meters.

"Belaz" and "Caterpillar" alternate. By the way, an imported dump truck transports only 180 tons.

Soon the Hitachi driver will become interested in this pile too.

Iron ore has an interesting texture.

Every day, 133 units of basic mining equipment (30 heavy-duty dump trucks, 38 excavators, 20 drilling machines, 45 traction units) operate in the quarry of the Lebedinsky GOK.

Smaller Belaz

It was not possible to see the explosions, and it is rare that the media or bloggers are allowed to witness them due to safety standards. Such an explosion occurs once every three weeks. All equipment and workers are removed from the quarry according to safety standards.

Well, then dump trucks unload the ore closer to the railway right there in the quarry, from where other excavators reload it into dump cars, which I wrote about above.

Then the ore is taken to a processing plant, where ferruginous quartzites are crushed and the process of separating the waste rock using the magnetic separation method takes place: the ore is crushed, then sent to a magnetic drum (separator), to which, in accordance with the laws of physics, all iron sticks, and not iron is washed away water. After this, the resulting iron ore concentrate is made into pellets and HBI, which is then used for steel smelting.

The photo shows a mill grinding ore.

There are such drinking bowls in the workshops; after all, it’s hot here, but there’s no way without water.

The scale of the workshop where ore is crushed in drums is impressive. The ore is ground naturally when the stones hit each other as they rotate. About 150 tons of ore are placed in a drum with a seven-meter diameter. There are also 9-meter drums, their productivity is almost double!

We went into the workshop control panel for a minute. It’s quite modest here, but the tension is immediately felt: dispatchers are working and monitoring the work process at control panels. All processes are automated, so any intervention - be it stopping or starting any of the nodes - goes through them and with their direct participation.

The next point on the route was the complex of the third stage of the hot briquetted iron production workshop - TsGBZh-3, where, as you may have guessed, hot briquetted iron is produced.

The production capacity of TsHBI-3 is 1.8 million tons of products per year, the total production capacity of the company, taking into account the 1st and 2nd stages for the production of HBI, has increased in total to 4.5 million tons per year.

The TsGBZh-3 complex occupies an area of ​​19 hectares and includes about 130 facilities: charge and product screening stations, tracts and transportation of oxidized pellets and finished products, dust removal systems for lower sealing gas and HBI, pipeline racks, pressure reduction station natural gas, sealing gas station, electrical substations, reformer, process gas compressor and other facilities. The shaft furnace itself is 35.4 m high and is housed in an eight-tier metal structure 126 meters high.

Also, as part of the project, the modernization of related production facilities was also carried out - the processing plant and the pelletizing plant, which ensured the production of additional volumes of iron ore concentrate (iron content more than 70%) and high-base pellets of improved quality.

The production of HBI today is the most environmentally friendly way to obtain iron. Its production does not generate harmful emissions associated with the production of coke, sinter and cast iron, and there is also no solid waste in the form of slag. Compared to pig iron production, energy costs for HBI production are 35% lower and greenhouse gas emissions are 60% lower.
HBI is produced from pellets at a temperature of about 900 degrees.

Subsequently, iron briquettes are formed through a mold, or as it is also called a “briquette press”.

This is what the product looks like:

Well, now let's sunbathe a little in the hot shops! This is the Oskol Electrometallurgical Plant, in other words OEMK, where steel is melted.

You can’t come close, you can feel the heat palpably.

On the upper floors, hot, iron-rich soup is stirred with a ladle.

Heat-resistant steelmakers do this.

I slightly missed the moment of pouring the iron into a special container.

And this is a ready-made iron soup, please come to the table before it gets cold.

And another one like that.

And we move on through the workshop. In the picture you can see samples of steel products that the plant produces.

The production here is very textured.

In one of the plant's workshops these steel blanks are produced. Their length can reach from 4 to 12 meters, depending on the wishes of customers. The photo shows a 6-strand continuous casting machine.

Here you can see how the blanks are cut into pieces.

In the next workshop, hot workpieces are cooled with water to the required temperature.

And this is what the already cooled, but not yet processed products look like.

This is a warehouse where such semi-finished products are stored.

And these are multi-ton, heavy shafts for rolling iron.

In the neighboring workshop, OEMK grinds and polishes steel rods of different diameters, which were rolled in previous workshops. By the way, this plant is the seventh largest enterprise in Russia for the production of steel and steel products.

After polishing, the products are in a neighboring workshop.

Another workshop where turning and polishing of products takes place.

This is how they look in their raw form.

Putting polished rods together.

And storage by crane.

The main consumers of OEMK metal products are Russian market are enterprises of the automotive, engineering, pipe, hardware and bearing industries.

I like neatly folded steel rods).

OEMK uses advanced technologies, including direct iron reduction and electric arc melting technology, which ensures metal production High Quality, with reduced impurity content.

OEMK metal products are exported to Germany, France, the USA, Italy, Norway, Turkey, Egypt and many other countries.

The plant produces products used by the world's leading automakers, such as Peugeot, Mercedes, Ford, Renault, and Volkswagen. They are used to make bearings for these same foreign cars.

At the customer's request, a sticker is attached to each product. The sticker is stamped with the heat number and steel grade code.

The opposite end can be marked with paint, and each bag can be marked with finished products Tags are attached with the contract number, destination country, steel grade, heat number, size in millimeters, supplier name and package weight.

Thank you for reading to the end, I hope you found it interesting.
Special thanks to the Metalloinvest campaign for the invitation!

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