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, with the help of carbon dioxide, which removes 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.

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, stucco 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-blowing 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.

From the beginning of the 17th 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 - the use of coal in metallurgy.

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 small savings on charcoal - most of the 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 melt the metal within a certain time. 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).

There are various ways to extract 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.

The process of obtaining iron begins with the stage of smelting pig iron, which contains a significant amount of carbon (which enters the pig iron from the coke or charcoal used to smelt the ore). Cast iron is very hard, but it is brittle. Carbon can be completely removed from cast iron. The resulting wrought iron is a malleable but relatively soft material. A certain amount of carbon is reintroduced into it and the result is steel that has sufficient toughness and at the same time sufficient hardness.

Calculate the amount of electricity required to smelt 1 ton of cast iron in an electric furnace, if we assume a) the reduction reaction of iron in the furnace proceeds according to the following diagram:

All metallurgical processes can be divided into primary and secondary. Primary processes mean the extraction of metal from various natural or artificial raw materials (blast furnace process, direct extraction of iron, smelting of ferrous

During all smelting processes, liquid steel contains a small amount of dissolved oxygen (up to 0.1%). During steel crystallization, oxygen reacts with dissolved carbon to form carbon monoxide (C). This gas (as well as some other gases dissolved in liquid steel) is released from the steel in the form of bubbles. In addition, oxides of iron and metal impurities are released along the grain boundaries of steel. All this leads to a deterioration in the mechanical properties of steel.

Manganese is mined in the form of ferromanganese, containing 85-88% manganese, up to 7% carbon, the rest is iron. Ferromanganese is smelted from a mixture of manganese and iron ores using coal as a reducing agent. Reaction equation for the reduction of MnOz

During the oxidation of carbon and impurities, part of the metallic iron is oxidized to FeO oxide (metal waste). To reduce metal losses, it is regenerated, that is, reduced to iron. In accordance with this, in the process of steel smelting, two sequential periods are distinguished - oxidative and reduction, which can be represented by the diagram

B. The recovery period of smelting during oxygen-converter steel smelting is spatially separated from the oxidation period and occurs after the steel is released from the converter in the ladle. Simultaneously with the reduction of iron oxide FeO in the reduction

The technological process of processing iron ore, coal, limestone and hydrocarbon fuels into the final product can be divided into 3-4 main stages, which are carried out separately to obtain a specific product, which at the next stage is processed into a new type of product. Different stages of the process can take place in one process plant. This will not only save energy and transportation costs, but also simplify the technological process. The main technological stages in the production of cast iron and steel are the following: preparation of raw materials (coking of coal, roasting of limestone, production of iron ore sinter and pellets) production of cast iron (blast smelting, production of sponge cast iron through direct reduction of iron) steel (in open-hearth and electric arc furnaces, Bessemer and basic oxygen converters) rolled products (continuous casting of billets, rolling of long steel, production of pipes, forgings).

The first metals used were probably gold and silver, since they could be found in nature in a free state. They were used mainly in decorative products. Copper began to be used around 8000 BC for the manufacture of tools, weapons, kitchen utensils and jewelry. Around 3800 BC, bronze was invented - an alloy of copper and tin. As a result, humanity moved from the Stone Age to the Bronze Age. Then a way to smelt iron was found, and the Iron Age began. As people accumulated their chemical experience, the range of useful materials that man learned to obtain by processing a wide variety of ores expanded.

Pyrometallurgical methods of copper smelting are not advisable for processing low-grade ores that cannot be enriched. This category includes oxidized ores, both low-grade and higher-grade, as well as dumps of low-grade sulfide ores and tailings from processing. For this raw material, methods are used to leach copper from the ore and extract it from solutions through iron precipitation or electrolysis with insoluble anodes.

The most common ore from which chromium is obtained is chromium iron ore PeCgaO. Calculate the content (in percentage) of impurities in the ore, if it is known that from 1 ton of it during smelting, 240 kg of ferrochrome (an alloy of iron and chromium) containing 65% chromium was obtained.

What is the relative content by weight of iron in this ore (in percent) How much carbon will be needed to smelt iron from

The complex use of polymetallic sulfide ores produces a variety of non-ferrous metals, sulfuric acid and iron oxide for smelting cast iron. Examples of the integrated use of natural materials, which are mixtures of organic substances, include coking of coal with accompanying chemical production, processing of oil, shale, peat and wood. Hundreds of products are obtained from each type of fuel. Previously, when coking coal, the only product of the process was coke, the gas was burned in furnaces, and the tar was discarded. Currently, benzene hydrocarbons, ammonia, hydrogen sulfide and other valuable substances are isolated from coke oven gas.

Glass smelting. Glass can be transparent or translucent, colorless or colored. It is a product of high-temperature remelting of a mixture of silicon (quartz or sand), soda and limestone. To obtain specific or unusual optical and other physical properties, other materials (aluminum, potash, sodium borate, lead silicate or barium carbonate) are used as an additive to the melt or as a substitute for part of the soda and limestone in the charge. Colored melts are formed as a result of the addition of iron or chromium oxides (yellow or green), cadmium sulfide (orange), cobalt oxides (blue), manganese (purple) and nickel (purple). The temperatures to which these ingredients must be heated exceed 1500 °C. Glass does not have a specific melting point and softens to a liquid state at a temperature of 1350-1600 ° C. Energy consumption even in well-designed furnaces is approximately 4187 kJ/kg glass produced. The required flame temperature (1800-1950 °C) is achieved by burning gas mixed with air, heated to 1000 °C in a regenerative heat exchanger, which is constructed of refractory bricks and heated by combustion waste products. Gas is blown into a stream of hot air through the side walls of the upper head of the regenerator, which is the main combustion chamber, and the combustion products, having given off heat to the glass melt, leave the furnace and go into the regenerator located opposite. When the temperature of the heating air supplied to combustion decreases significantly, the flows of air and combustion products are reversed and gas begins to flow into the air flow heated in the regenerator located opposite.

Corona electrodes in vertical electrostatic precipitators are thin round wire, wire with small spikes, or wire with a square or star-shaped cross-section. Since corona electrodes are often over 6m long, round wire, while thin enough to provide a stable corona, may not be strong enough, especially as it is subject to vibration during shaking. In this regard, larger gauge wire is used with a square or star-shaped cross-section, with sharp edges, which ensure the formation of a stable crown. In some electrostatic precipitators, barbed wire electrodes are preferred, and most recently they have been used to deposit iron oxide mist in oxygen steel smelting.

The principle of using industrial waste (integrated use of raw materials, waste-free technology). Converting waste into production by-products allows for better use of raw materials, which in turn reduces the cost of production and prevents environmental pollution. For example, complex processing of polymetallic sulfide ores produces non-ferrous metals, sulfur, sulfuric acid and iron (III) oxide for smelting cast iron. The integrated use of raw materials serves as the basis for combining enterprises. At the same time, new industries arise that process waste from the main enterprise, which gives a high economic effect and is an important element of the chemicalization of the national economy.

Metals can be extracted from their ores directly by electrolytic or chemical reduction. Electrolytic reduction, which has already been discussed in Sect. 19.6, is used on an industrial scale to obtain the most active metals sodium, magnesium and aluminum. Less reactive metals - copper, iron and zinc - are produced on an industrial scale by chemical reduction, with most of the less reactive metals obtained by high-temperature molten reduction. Therefore, such processes are called smelting.

Carbon dioxide is produced by the reduction of iron oxide [Equation (22.20)] and also by the decomposition of limestone. But limestone plays not only the role of a supplier of carbon dioxide in iron smelting. Typically, the recovered ore contains

When smelting iron, slag floats on the surface of the molten metal, protecting it from oxidation by incoming air. The resulting iron and slag are periodically removed from the furnace. Iron produced in a blast furnace is called cast iron and contains up to 5% carbon and up to 2% other impurities - silicon, phosphorus and sulfur.

When cast iron is smelted in a blast furnace, various chemical processes occur, in particular the reduction of iron (III) oxide by carbon (II) oxide, which can be expressed by the equation Fe203 + 3C0 = Fe-(-3C02.

Chemical reactions during the smelting of iron and steel occur primarily in solutions. Liquid iron and steel are solutions of various elements in iron. In blast furnaces and steel-smelting furnaces they interact with liquid slag - a solution of oxides.

Selenium and tellurium are found in such rare minerals as Cl33e, Pb5e, A25e, Cu2Te, PbTe, A2Te and AuTe, and also as impurities in sulfide ores of copper, iron, nickel and lead. From an industrial point of view, copper ores are important sources of extraction of these elements. During the firing process of smelting copper metal, most of the selenium and tellurium remain in the copper. During the electrolytic purification of copper, described in Sect. 19.6, impurities such as selenium and tellurium, along with the precious metals gold and silver, accumulate in the so-called anode sludge. When anode sludge is treated with concentrated sulfuric acid at approximately 400°C, selenium is oxidized into selenium dioxide, which sublimes from the reaction mixture

In some cases (for example, when smelting transformer steel) it is necessary to achieve a very low carbon concentration of 0.002-0.003%. From the above equation it is clear that for this purpose it is necessary to reduce pco. The use of vacuum furnaces in modern metallurgy makes it possible to smelt iron and steel with a minimum carbon content.

When smelting iron from magnetic iron ore, one of the reactions occurring in a blast furnace is expressed by the equation Res04 + CO = 3ReO + Oj Using the data in Table. 5 applications, determine the thermal effect of the reaction. In what direction will the equilibrium of this reaction shift if the temperature increases?

Magnetic iron ore Oxide iron ore iron content 50-70%, consists mainly of iron oxide (11, ill) RbzO, Raw material for the production of cast iron, additive in steel production (smelting)

U-88. From 1 ton of chromium iron ore Fe(CrO2)a was formed during the smelting of 240 kg of an alloy of iron and chromium - ferrochrome, containing 65% chromium. Calculate the percentage of impurities in the ore.

When smelting high-chromium steels of the X18N10T type, a peculiar scallop with an increased content of AlA TiO (up to 33%), iron oxides (up to 57%) and chromium oxides (up to 33%) is formed on the working surface of the refractory lining, which leads to an increase in the service life of the lining .

As a result, two liquid layers are formed in the furnace - lighter slag on top, and a melt consisting of FeS and U2S (matte) below. The slag is drained, and the liquid matte is poured into a converter, into which flux is added and air is blown in. The converter for smelting copper is similar to that used for producing steel, only air is supplied into it from the side (when air is supplied from below, the copper is greatly cooled and hardens). Molten copper is formed in the converter, iron sulfide turns into oxide, which turns into slag

The final sulfur content in calcined coke from Arlan oil tar is the same as in coke from the cracked residue of Romashkin oil, i.e. less than 1%. The remaining indicators are basically the same, with the exception of the content of vanadium (1.5 times higher for Arlan coke), iron and other metals. The increased content of vanadium in desulfurized coke is explained by its high content in Arlan oil. Because of this, such coke cannot be used in the aluminum industry. When smelting aluminum, vanadium, like other metals, is produced from coke

The work describes the effect of manganese on sulfide cracking of steels. Manganese in an amount from 1 to 167o was introduced during the smelting of reinforced iron containing 0.04% C, into steel 20, and into U8 steel. The research results are given in table. 1.2, from which it can be seen that alloying steels with manganese increases their susceptibility to cracking in a hydrogen sulfide-containing environment, and the negative effect of manganese depends on the carbon content in the steel. Thus, the negative effect of manganese for reinforced iron, steel 20 and steel U8 begins to appear at its content of 3 2 n 1%, respectively. The authors associate the negative effect of manganese on cracking of steels with the appearance of

In metallurgy, an alloy of iron and silicon - ferrosilicon - is of great importance. It is used for deoxidation of many grades of steel and for the production of silicon-carbon ferroalloys. Ferrosilicon with a content of 9-17% 51 is smelted in blast furnaces from quartz, iron filings and coke. Ferrosilicon with a high silicon content is a promising material for the manufacture of parts for chemical equipment due to its exceptional acid resistance. It is widely used as a reducing agent in the smelting of silicomanganese, ferrotungsten, and ferromolybdenum. The addition of silicon to steel in the form of ferrosilicon during its smelting gives it elasticity and increases resistance to corrosion.

Some features of a typical smelting process can be illustrated by the example of iron reduction. Continuous smelting of iron is carried out in a special reactor called a blast furnace; its schematic representation is shown in Fig. 22.16. A mixture of coke, limestone and crushed ore, usually containing FejOs, is loaded onto the top of the blast furnace. (Coke is a solid residue obtained by coking natural fuels, mainly coal, to remove volatile components from them.) Heated air, sometimes enriched with oxygen, is pumped into the furnace from below. To obtain 1 ton of iron, approximately 2 tons of ore, 1 ton of coke and 0.3 tons of limestone are required. One blast furnace can produce up to 2000 tons of iron per day. Air pumped into the furnace reacts with carbon to form CO. In this case, such an amount of heat is released that a temperature of about 1500°C develops in the lower part of the furnace. The reduction of metallic iron can be described by the reactions

How many tons of magnetic iron ore, consisting of 90% FegOi, can be produced when smelting 2 tons of pig iron with 93% iron content, if the product yield is 92%

The introduction of silicon into steel and cast iron is accompanied by the formation of iron silicides (ferrosilicon FeSi). Cast iron containing 15-17% silicon is acid-resistant. Ferrosilicon is added to steel when it is smelted to remove the oxygen it contains.

MATE is an intermediate product in the smelting of some non-ferrous metals (Cu, N1, Pv, etc.) from their liquid ores. Sh. - an alloy of iron sulfide with sulfides of the resulting metals (for example, Cu, 8).

The phenomenon of lowering the melting point of solutions is important both in nature and in technology. For example, the smelting of cast iron from iron ore is greatly facilitated by the fact that the melting point of iron is lowered by approximately 400 ° C due to the fact that carbon and other solvent elements are dissolved in it. The same applies to the refractory oxides that make up the waste rock, which together with fluxes (CaO) form a solution (slag) that melts at a relatively low temperature. This makes it possible to carry out a continuously batch process in blast furnaces, releasing liquid iron and slag from them. ]

First, I’ll tell you about the quarry itself. Lebedinsky GOK is the largest Russian enterprise for the extraction and enrichment of iron ore and has the largest iron ore mine in the world. The plant and quarry are located in the Belgorod region, between the cities of Stary Oskol and Gubkin.

View of the quarry from above. 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.

Some official information: Lebedinsky GOK is part of the Metalloinvest concern and is the leading producer of iron ore products in Russia. In 2011, the share of concentrate production by the plant in the total annual production of iron ore concentrate and sinter ore in Russia amounted to 21%.

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.

Each year, both plants included in the company (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 baby 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.

Recently, BelAZ trucks with a lifting capacity of 160 and 220 tons were purchased (until now, the loading capacity of dump trucks in quarries was no more than 136 tons), and the arrival of Hitachi excavators with a bucket capacity of 23 cubic meters is expected. (currently the maximum bucket capacity of mining excavators is 12 cubic meters).

Belaz and Caterpillar alternate. By the way, an imported dump truck transports only 180 tons. Dump trucks with such a large carrying capacity are new equipment that is currently supplied to mining and processing plants as part of Metalloinvest’s investment program to increase the efficiency of the mining and transport complex.

The stones have an interesting texture, pay attention. If I’m not mistaken on the left, quartzite is the kind of ore that iron is extracted from. The quarry is full of not only iron ore, but also various minerals. They are generally of no interest for further processing on an industrial scale. Today, chalk is obtained from waste rock, and crushed stone is also made for construction purposes.

Beautiful stones, I can’t say exactly what kind of mineral it is, can someone tell me?

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.

Of course, I hoped to see spectacular explosions, but even if they took place that day, I still would not have been able to penetrate the quarry territory. This explosion is done once every three weeks. All equipment according to safety standards (and there is a lot of it) is removed from the quarry before this.

Lebedinsky GOK and Mikhailovsky GOK are the two largest iron ore mining and processing plants in Russia in terms of production volume. The Metalloinvest company has the world's second largest proven reserves of iron ore - about 14.6 billion tons according to the international JORC classification, which guarantees about 150 years of exploitation period at the current level of production. So the residents of Stary Oskol and Gubkin will be provided with work for a long time.

You probably noticed from the previous photographs that the weather was not good, it was raining, and there was fog in the quarry. Closer to departure, it dissipated slightly, but still not much. I pulled out the photo as much as possible. The size of the quarry is certainly impressive.

Right in the middle of the quarry there is a mountain of waste rock, around which all the ore containing iron was mined. Soon it is planned to blow it up in parts and remove it from the quarry.

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 105 tons.

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

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

Then the ore is taken to the plant, where the process of separating the waste rock using the magnetic separation method takes place: the ore is crushed finely, then sent to a magnetic drum (separator), to which, in accordance with the laws of physics, everything that is iron sticks, and what is not iron is washed off with water. The resulting iron ore concentrate is then used to make pellets and hot briquetted iron (HBI), which is then used to make steel.
Hot briquetted iron (HBI) is one of the types of direct reduced iron (DRI). Material with a high (>90%) iron content, obtained using a technology other than blast furnace processing. Used as a raw material for steel production. High-quality (with a small amount of harmful impurities) substitute for cast iron and scrap metal.

Unlike cast iron, HBI production does not use coal coke. The process of producing briquetted iron is based on processing iron ore raw materials (pellets) at high temperatures, most often through natural gas.

You can’t just go inside the HBI plant, because the process of baking hot briquetted pies takes place at a temperature of about 900 degrees, and sunbathing in Stary Oskol was not part of my plans).

Lebedinsky GOK is the only producer of HBI in Russia and the CIS. The plant began production of this type of product in 2001, launching a workshop for the production of HBI (HBI-1) using HYL-III technology with a capacity of 1.0 million tons per year. In 2007, LGOK completed the construction of the second stage of the HBI production workshop (HBI-2) using MIDREX technology with a production capacity of 1.4 million tons per year. Currently, the production capacity of LGOK is 2.4 million tons of HBI per year.

After the quarry, we visited the Oskol Electrometallurgical Plant (OEMK), part of the Metallurgical segment of the company. 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.

Do you see a bunch of sparks? A piece of steel is cut off at that point.

An interesting machine with a bucket, called a bucket carrier, into which slag is poured during the production process.

In the neighboring workshop, OEMK grinds and polishes steel rods of different diameters, which were rolled in another workshop. By the way, this plant is the seventh largest enterprise in Russia for the production of steel and steel products. In 2011, the share of steel production at OEMK amounted to 5% of the total volume of steel produced in Russia, the share of rolled products production also amounted to 5%.

OEMK uses advanced technologies, including direct reduction of iron and electric arc melting, which ensures the production of high-quality metal with a reduced content of impurities.

The main consumers of OEMK metal products on the Russian market are enterprises in the automotive, machine-building, pipe, hardware and bearing industries.

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

The plant has mastered the production of long products for the manufacture of products used by the world's leading automakers, such as Peugeot, Mercedes, Ford, Renault, and Volkswagen. Some products are used to make bearings for these same foreign cars.

By the way, this is not the first time I have noticed women crane operators in such industries.

This plant has an almost sterile cleanliness, which is not typical for such industries.

I like the neatly folded steel rods.

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 tags with the contract number, country of destination, steel grade, heat number, size in millimeters, supplier name and weight of the package are attached to each package of finished products.

These products are the standards by which equipment for precision rolling is adjusted.

And this machine can scan the product and identify microcracks and defects before the metal reaches the customer.

The company takes safety precautions seriously.

All water used in production is purified by recently installed state-of-the-art equipment.

This is the plant's wastewater treatment plant. After processing, it is cleaner than in the river where it is dumped.

Technical water, almost distilled. Like any industrial water, you cannot drink it, but you can try it once, it is not dangerous to your health.

The next day we went to Zheleznogorsk, located in the Kursk region. This is where the Mikhailovsky GOK is located. The photo shows the complex of roasting machine No. 3 under construction. Pellets will be produced here.

$450 million will be invested in its construction. The enterprise will be built and put into operation in 2014.

This is a layout of the plant.

Then we went to the quarry of the Mikhailovsky GOK. The depth of the MGOK quarry is more than 350 meters from the surface of the earth, and its size is 3 by 7 kilometers. There are actually three quarries on its territory, as can be seen in the satellite image. One big and two smaller. In about 3-5 years, the quarry will grow so much that it will become one large unified one, and perhaps will catch up in size with the Lebedinsky quarry.

The quarry uses 49 dump trucks, 54 traction units, 21 diesel locomotives, 72 excavators, 17 drilling rigs, 28 bulldozers and 7 motor graders.

Otherwise, ore production at MGOK is no different from LGOK.

This time we still managed to get to the plant, where iron ore concentrate is converted into the final product - pellets..
Pellets are lumps of crushed ore concentrate. Semi-finished product of metallurgical iron production. It is a product of the enrichment of iron-containing ores using special concentrating methods. Used in blast furnace production to produce cast iron.

Iron ore concentrate is used to produce pellets. To remove mineral impurities, the original (raw) ore is finely crushed and enriched in various ways.

The process of making pellets is often called “pelletizing”. The charge, that is, a mixture of finely ground concentrates of iron-containing minerals, flux (additives that regulate the composition of the product), and strengthening additives (usually bentonite clay), is moistened and subjected to pelletization in rotating bowls (granulators) or pelletizing drums. They are the ones in the picture.

Let's come closer.

As a result of pelletization, nearly spherical particles with a diameter of 5÷30 mm are obtained.

It's quite interesting to watch the process.

Then the pellets are sent along a belt to the firing body.

They are dried and fired at temperatures of 1200÷1300° C in special installations - firing machines. Calcining machines (usually the conveyor type) are a conveyor of calcining carts (pallets) that move on rails.

But the picture shows the concentrate that will soon end up in the drums.

In the upper part of the roasting machine, above the roasting carts, there is a heating furnace, in which gaseous, solid or liquid fuel is burned and a coolant is formed for drying, heating and roasting the pellets. There are roasting machines with cooling of pellets directly on the machine and with an external cooler. Unfortunately, we did not see this process.

The fired pellets acquire high mechanical strength. During firing, a significant portion of sulfur contaminants is removed. This is what the ready-to-eat product looks like.)

Despite the fact that the equipment has been in service since Soviet times, the process is automated and does not require a large number of personnel to control it.

History of iron metallurgy

Iron... The depths of our planet are rich in this metal, which is rightly called the “foundation of civilization.” As if in order not to part with its treasures, nature, having firmly bound iron with other elements (mainly oxygen), hid it in various ore minerals. But already in ancient times - in the second millennium BC - man learned to extract the metal he needed.

Historically, the production of ferrous metals developed in the following stages:

Cheese-making process (1500 BC). The productivity of the process is very low; in 1 hour only up to 0.5...0.6 kg of iron was obtained. In forges, iron was reduced from ore with coal when blown with air using forge bellows. First, when burning charcoal, carbon monoxide was formed, which reduced pure iron from the ore.

As a result of long-term air blowing, pieces of ore were obtained from pieces of ore, practically without impurities, into pieces of pure iron, which were welded together using a forge into strips, which were then used to produce products necessary for humans. This technically pure iron contained very little carbon and few impurities (pure charcoal and good ore), so it forged and welded well and practically did not corrode. The process took place at a relatively low temperature (up to 1100...1350 o C), the metal did not melt, i.e., the reduction of the metal took place in the solid phase. The result was malleable iron. This method existed until the 14th century, and in a slightly improved form until the beginning of the 20th century, but was gradually replaced by critical redistribution.

It follows that historically the very first metal welder was a blacksmith, and the very first welding method was forge welding.

With the increase in the size of the cheese furnaces and the intensification of the process, the carbon content in iron increased, the melting point of this alloy (cast iron) turned out to be lower than that of purer iron, and part of the metal was obtained in the form of molten cast iron, which, as a production waste, flowed out of the furnace along with the slag. In the 14th century, a two-stage method for producing iron was developed in Europe (a small blast furnace, then a furnace process). Productivity increased to 40...50 kg/hour of iron. A water wheel was used to supply air. Krichny redistribution- this is the process of refining cast iron (reducing the amount of C, Si, Mn) in order to obtain welding iron from cast iron.

At the end of the 18th century in Europe, mineral fuels began to be used in the blast furnace process and in puddling process. In the puddling process, coal is burned in a furnace, gas passes through the bath, melts and purifies the metal. In China, even earlier, in the 10th century, cast iron was smelted, and then steel was obtained by the process of puddling. Pudding is the cleaning of cast iron in a fiery furnace. During cleaning, iron grains collect into clumps. The pudliner turns the mass over and over with a crowbar and divides it into 3...5 parts - krits. In a forge or rolling machine, grains are welded to produce strips and other blanks. Steam engines are already used instead of a water wheel. Productivity increases to 140 kg of wrought iron per hour.

At the end of the 19th century, three new steel production processes were introduced almost simultaneously: Bessemer, open-hearth and Thomas. Steel melting productivity increases sharply (up to 6 tons/hour).

In the middle of the 20th century: oxygen blasting, process automation and continuous casting of steel were introduced.

During the cheese-blowing, krichny and puddling processes, iron did not melt (the technical level of that time did not make it possible to ensure its melting temperature). Blowing oxygen through the molten metal in a Bessemer converter, due to the sharp increase in the contact surface of the metal with the oxidizing agent (oxygen), accelerates chemical reactions a thousand times compared to a puddling furnace.

In the cheese-blowing and casting processes, malleable, wrought iron (low-carbon steel) was obtained in a single-stage method, which had a small amount of impurities and was therefore very resistant to corrosion. Currently, a one-stage steel production process is under development: ore beneficiation (production of pellets containing 90...95% iron) and steel smelting in an electric furnace.

The entire history of iron metallurgy, from the time of the appearance of the first smelting pits until the present day, is a continuous improvement of methods for its production. Several centuries ago, a blast furnace appeared - a high-performance unit in which iron ore is converted into cast iron - the initial product for steel smelting. Since then, the blast furnace process has become the main element of steel production technology.

The process of extracting iron from ore in a forge went down in the history of metallurgy under the name “cheese blast”, since unheated - raw - air was blown into the forge (hot blast appeared in metallurgical plants only in the 19th century). The iron produced in the cheese furnace sometimes turned out to be insufficiently strong and hard, and products made from it - knives, axes, spears - did not remain sharp for long, bent, and quickly failed.

At the bottom of the forge, along with relatively soft lumps of iron, there were also harder ones - those that were in close contact with charcoal. Noticing this pattern, man began to consciously increase the contact area with coal and thereby carbonize the iron. Now the metal could satisfy the most demanding craftsman. It was steel - the most important alloy of iron, which to this day serves as the main structural material.

The demand for steel has always and almost everywhere outpaced its production, and primitive metallurgical technology has long lagged behind the requirements of life. Surprisingly, for almost three thousand years, iron metallurgy has not undergone any fundamental changes - the production of iron and steel was based on the same cheese-blowing process. True, the size of the forges gradually increased, their shape improved, and the blowing power increased, but the technology remained ineffective.

In the Middle Ages, the cheese furnace took the form of a shaft furnace, reaching a height of several meters. In Russia, these furnaces were called domnitsa - from the ancient Russian word “dmenie”, meaning “blowing”. They were already loaded with a significant amount of charge materials - iron ore and charcoal, and air was required many times more than for primitive cheese-blowing forges. Now the furnaces “breathed” using water energy: the bellows were driven first by special water pipes, and later by huge water wheels.

In a shaft furnace, more fuel was burned per unit time than in a forge and, naturally, more heat was released. It was the high temperatures in the furnace that led to the fact that part of the reduced iron, freed from oxygen, but highly saturated with carbon, melted and flowed out of the furnace. When solidified, such an iron-carbon alloy, containing several times more carbon than steel, became very hard, but also very brittle. It was cast iron.

Its role in the development of metallurgy is very important, but several centuries ago iron masters had a completely different opinion; after all, under the blows of a hammer, such metal shattered into pieces, and it was simply impossible to make a weapon or tool out of it. At the same time, because of this useless alloy, the amount of a good product - iron grain - was sharply reduced.

What nicknames did medieval metallurgists give to the new alloy? In the countries of Central Europe it was called wild stone, goose, in England - pig iron (in English, cast iron is still called that way), and the Russian word pig, that is, cast iron ingot, has the same origin.

Since cast iron had no use, it was usually thrown into a landfill. But in the 19th century, someone came up with the happy idea of ​​loading cast iron back into the furnace and smelting it along with the ore. This attempt marked a real revolution in iron metallurgy. It turned out that this method makes it relatively easy to obtain the required steel, and in large quantities. Alas, history has not preserved for us the name of this medieval inventor.

The innovation led to a clear division of “labor”: in blast furnaces, which by that time had already become more advanced blast furnaces, cast iron was smelted from ore, and in furnaces, excess carbon was removed from it, that is, the process of converting cast iron into steel was carried out - “critical processing” . This is how a two-stage method of producing steel from iron ore arose: ore - cast iron, cast iron - steel.

Now the demand for cast iron, primarily as an intermediate product, which is then converted into steel, has increased sharply. And blast furnaces grew everywhere like mushrooms after rain. But since blast furnace smelting required a lot of charcoal, soon in those countries that were not rich in forests, its shortage began to be acutely felt, and metallurgy, deprived of fuel, began to decline here. This happened, for example, in England, which for a long time occupied a dominant position in iron production.

The difficult situation in which English industry found itself in connection with this forced metallurgists to look for a replacement for charcoal. First of all, their attention was attracted by coal, which nature generously endowed the British Isles with. However, all attempts to smelt cast iron on it ended in failure: the coal was crushed during the heating process, and this made blowing very difficult. But finally, in 1735, the Englishman Abraham Derby managed to carry out a blast furnace process using coke - fuel obtained from coking coal by heating it without air access to high temperatures (950-1050 ° C), while the coal was not crushed, but sintered into pieces . Today, neither blast furnace smelting nor a number of other metallurgical processes are unthinkable without coke.

The 18th and 19th centuries brought a lot of new things into the design of the blast furnace: the first blowing machines were invented, and a “guard of honor” grew up next to the blast furnace - huge blunt-nosed cigars of air heaters, thanks to which hot air is now supplied to the furnace.

An ancient forge for obtaining an iron cry. Horn with air blast (XVI century). Blast furnace (late 18th century)

Great changes also occurred at the second stage of metallurgical production. At first, the screaming forge gave way to a more advanced furnace - the puddling furnace. Here, molten cast iron was mixed (hence the name of the furnace - from the English word puddle - to mix) together with ferrous slag and as a result, low-carbon iron was obtained. And in the second half of the last century, more productive steel-smelting units were created - a converter and an open-hearth furnace. In them, cast iron no longer turned into a dough-like mass - kritsa, but into liquid steel.

Then another important page was written in the history of metallurgy: an arc steel-smelting furnace was designed, which made it possible to produce high-quality metal. The flame, which for thousands of years had a monopoly on all rights to melt metals, now has a serious competitor - electric current.

In recent decades, metallurgy has seen a kind of “acceleration”: the sizes of all kinds of furnaces are growing from year to year. It’s been a long time since blast furnaces with a volume of two thousand cubic meters were considered almost a wonder of the world, but today there are much more impressive colossi in the world - “four thousand meters” and even “five thousand meters”.

Blast furnaces will undoubtedly remain important for a long time to come. Nevertheless, their fate can hardly be considered cloudless. Unlike the primitive ancient forge, in which our ancestors obtained iron directly from ore, the modern gigantic structure - the blast furnace - produces mainly not the metal that technology directly requires, but only a conversion product, which is then converted at the next stage into the steel we need (the exception is foundry iron used for the production of castings; its share in the total volume of cast iron produced does not exceed 15 percent). In other words, in an effort to achieve high quantitative indicators, metallurgists are forced to take a kind of roundabout route.

The question of changing the technological route in steel production has long occupied scientists. And the point here is not an idle desire to straighten the paths of ferrous metallurgy. The reason is different.

The blast furnace has a serious disadvantage. Its essence is, although it may seem strange at first glance, that an indispensable “dish” in her diet is coke. The same coke, the invention of which became a significant milestone in the development of iron metallurgy. After all, it is thanks to coke that the blast furnace has been receiving excellent high-calorie “nutrition” for two and a half centuries. But gradually clouds began to appear on the blast-furnace horizon, which can rightfully be called coke clouds.

What's the matter?

As is known, coke does not exist in nature. It is obtained from coal. But not any of them. But only those that have a tendency to coking (sintering). There are not very many such coals in the world, so from year to year they become more scarce and more expensive. And coal still needs to be turned into coke. This process is quite complex and labor-intensive, accompanied by the release of harmful by-products with by no means perfumery aromas. In order to rid the atmosphere, water, and soil of them as much as possible, it is necessary to build expensive treatment devices.

The rise in coke prices has led to the fact that it turns out to be the most significant item in the cost of cast iron: it accounts for approximately half of all costs. That is why blast furnace operators are constantly striving to reduce coke consumption, partially replacing it with natural gas, pulverized coal, and fuel oil, and considerable success has already been achieved here. So, perhaps, by developing an offensive against coke, the blast furnace workers will gradually be able to completely get rid of it? But then you will have to get rid of the blast furnace itself: after all, without coke it is like a stove without wood.

The founder of modern metallurgy, D.K. Chernov, dealt with the problems of coke-free metallurgy. At the end of the last century, he proposed an original design for a shaft furnace that would smelt iron and steel rather than cast iron. Unfortunately, his idea was not destined to come true. About a decade and a half after Chernov presented his project, he wrote bitterly: “Due to the usual inertia of our private factories, I turned to the Ministry of Trade and Industry in the hope of being able to implement the proposed method in a simplified form at one of the state-owned mining plants. However, despite the desire twice expressed by the then minister to help produce such an experience, this issue met with insurmountable obstacles among the cabinets and corridors of the ministry.”

D.I. Mendeleev was also a supporter of blast-free production. “I believe,” he wrote at the turn of the century, “that the time will come again to look for ways to directly obtain iron and steel from ores, bypassing cast iron.”

For decades, scientists and engineers from different countries have been striving to find an acceptable technology for the direct reduction of iron. Hundreds of patents were issued, various units, installations, and furnaces were proposed and created. However, even the most seemingly promising ideas could not be brought to life for a long time.

The first relatively successful industrial installation for the direct production of iron was built in 1911 in Sweden according to the design of engineer E. Sierin. The advantage of this technology was that. that the reducing agent that took oxygen away from iron was waste from coal and coke production (coal dust and fine fractions of coke), and the furnace itself was heated with cheap types of coal. In addition, the quality of the smelted metal was very high, for which Sweden has always been famous. However, this technology was not widely used because the process took several days. The Swedish installation could not compete with the well-functioning “duets” of blast furnace - open-hearth or blast furnace - converter.

An important step in the development of direct iron production technology was made in 1918, when the Swedish engineer M. Wiberg proposed conducting the reduction process in a shaft furnace using flammable gas containing carbon monoxide and hydrogen for this purpose. The method made it possible to convert ore into 95 percent iron. But (and here there are “buts”) this method had a significant drawback: the initial raw material for producing reducing gas was the same coke, and for its gasification complex and expensive devices were needed - electric gas generators.

In our country, V.P. Remin, associate professor of the Siberian Metallurgical Institute, was a great enthusiast of blast-furnace technology. Back in the late 30s, he developed the design of an electric furnace in which ore was supposed to be melted, sliding down an inclined bottom, like ice in the mountains (that’s why the furnace was called a glacier furnace), and then iron was supposed to be recovered from the melt. The treacherous attack on our country by Nazi Germany posed many difficult tasks for metallurgists, and these experiments had to be postponed until better times.

Blast furnace: 1 - skip; 2 - receiving funnel: 3 - charge distributor: 4 - air lance; 5 - cast iron taphole: 6 - slag taphole.

But even when they arrived, it turned out that the experts did not have a common point of view. Some unconditionally advocated for the blast furnace, tested over centuries, while others saw blast-free and coke-free prospects. In 1958, academician I.P. Bardin, speaking about the direct production of iron from ore, noted that “the famous American metallurgist Smith, who called the blast furnace a millstone hanging around the neck of metallurgy as punishment for its sins in the field of scientific research, was forced to consider specific processes to return to the blast furnace as the only unit at present on which metallurgy can be based.”

In those years, metallurgy really did not have a noteworthy alternative to the blast furnace. Despite numerous attempts to develop methods for obtaining iron directly from ore, it was not possible for a long time to find a solution that would unconditionally satisfy metallurgists. Either the technological scheme was imperfect, or the equipment turned out to be unreliable or ineffective, or the quality of the resulting metal left much to be desired. In addition, the proposed options were often not justified economically: the metal turned out to be very expensive. The choice of reducing agent also remained a difficult task. The search has reached a dead end, although in Sweden, the USSR, and the USA. Mexico, Venezuela, Germany and Japan operated several small installations for the direct extraction of iron from ores.

The fact that these countries were the first to introduce new technology was not surprising. For example, metallurgy in Sweden has long specialized in the production of high-quality steel, and, as practice has shown, the path of direct reduction is also a path to directly improve the quality of the metal. As for Mexico and Venezuela, they became leaders unwillingly - these countries do not have coking coal, but they have large reserves of natural gas, so they could not develop ferrous metallurgy on a traditional basis, that is, by building blast furnaces, even if they wanted to.

By the end of the 50s, metallurgists came to the firm conviction that gas should act as a reducing agent in the processes of direct iron production. This meant that further searches should be conducted in the direction proposed by Wiberg. Soon successful solutions were found in a number of countries. Thus, the advantage of one of the proposed technologies was that the reducing agent turned out to be practically free: the inventors proposed using the waste gas of electric steel-smelting shops, which was previously released into the atmosphere. There was another original solution. From the shaft furnace, where the reduction of iron took place, the hot gas was directed not to the heavens, but to the recuperator and gave up its heat to the reducing gas entering there.

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 iron ore mining and processing enterprise and has the world's largest iron ore mine. 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, since this interferes with the further development of the quarry and it is also being systematically mined.

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.

On this railway, which connects the quarry with the plants, 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 TsHBI-3 complex occupies an area of ​​19 hectares and includes about 130 objects: batch and product screening stations, tracts and transportation of oxidized pellets and finished products, dust removal systems for lower sealing gas and HBI, pipeline racks, a natural gas reduction station, a seal gas, 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 on the Russian market are enterprises in the automotive, machine-building, pipe, hardware and bearing industries.

I like neatly folded steel rods).

OEMK uses advanced technologies, including direct reduction of iron and electric arc melting, which ensures the production of high-quality metal with a reduced content of impurities.

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 tags with the contract number, country of destination, steel grade, heat number, size in millimeters, supplier name and weight of the package are attached to each package of finished products.

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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