Iron ore is a rock formation, which includes the natural accumulation of different minerals and must, in one or another ratio, is present, which can be paid out of ore. Components that are part of ore can be the most diverse. Most often, it contains the following minerals: hematite, martitite, siderite, magnetite and others. Quantitative iron content contained in ore, unequal, on average it ranges from 16 to 70%.
Depending on the amount of iron content in ore, it is divided into several types. Iron ore, containing more than 50% iron, is called rich. Conventional ores in their composition include at least 25% and not more than 50% iron. Poor ores have a small iron content, it is only a fourth one of the total number of chemical elements included in the total content of ore.
From iron ores in which sufficient iron content is paid, it is most often enriched for this process, but they can also be used in pure form, it depends on the chemical composition of ore. In order to produce, a precise ratio of certain substances is necessary. This affects the quality of the final product. From ore can be paid and used for destination and other elements.
In general, all deposits of iron ores are divided into three main groups, it is:
Magmatogenic deposits (formed under the influence of high temperatures);
exogenous fields (formed as a result of precipitation and weathering of rocks);
Metamorphogenic deposits (formed as a result of sedimentary activities and the subsequent effect of high pressure and temperature).
These basic groups of deposits may in turn divided into some subgroups.
Very rich in deposits of iron ore. Its territory contains more than half of the global deposits of the iron rock. The most extensive field includes a Bacchar deposit. This is one of the largest sources of iron ore deposits not only in the territory of the Russian Federation, but also around the world. This field is located in the Tomsk region in the area of \u200b\u200bAndrom and Iques Rivers.
Rude deposits were found here in 1960, during the search for oil sources. The field spread on a very extensive area of \u200b\u200b1600 square meters. meters. The deposits of iron ore are located at a depth of 200 meters.
Baccharian iron ores are rich in iron by 57%, they also include in their composition and other useful chemical elements: phosphorus, gold, platinum, palladium. The volume of iron in the enriched iron ore comes to 97%. The general stock of ore at this field is calculated in 28.7 billion tons. For mining and developing ore from year to year, technologies will be improved. Career prey suggests replace well.
In the Krasnoyarsk Territory, about 200 km from the city of Abakan, in the western direction, is the Abagas deposit of iron ore. The predominant chemical element, which is part of the local ores is magnetite, it complements musket, hematite, pyrite. The overall composition of iron in ore is not so large and is 28%. Active work on the extraction of ore at this field is conducted from the 80s, despite the fact that it was discovered back in 1933. The deposit consists of two parts: South and North. Every year in this place, it is mined a little more than 4 million tons of iron ore. The total number of iron ore reserves at the Abasian field is 73 million tons.
In Khakassia, not far from the city of Abaza in the West Sayan area, developed an abacious field. It was open in 1856, and since then the extraction of ore is carried out regularly. For the period from 1947 to 1959, special enterprises for the extraction and enrichment of ore were erected at the Abakan field. Initially, the prey was led by an open way, and later switched to an underground way, setting up a 400-meter mine. Local ores are rich in magnetite, pyrite, chlorite, calcite, actinolitis, andesite. The iron content in them is from 41.7 to 43.4% with the addition of sulfur and. The level of annual production is on average equal to 2.4 million tons. The total reserve of deposits is 140 million tons. In Abaz, Novokuznetsk and Abakan there are centers of mining and processing of iron ore.
Kursk magnetic anomaly is famous for its richest deposits of iron ore. This is the largest iron pool around the world. There are more than 200 billion tons of ore. This amount is a weighty indicator, because it is half the reserves of iron ore throughout the planet as a whole. There is a deposit on the territory of the Kursk, Oryol and Belgorod regions. Her borders extend within 160,000 square meters. km, including nine central and southern regions of the country. The magnetic anomaly was found here for a long time, back in the XVIII century, but the more extensive ore deposits became possible to detect only in the last century.
The richest reserves of iron ore began to actively produce here only in 1931. In this place is stored a supply of iron ore, equal to 25 billion tons. The iron content in it ranges from 32 to 66%. Mining is carried out and open, and underground ways. Kursk magnetic anomaly includes the most associated and the Chernyanskoye deposit of iron ore.
Iron is a common element in nature. Its content in the earth's crust is 4.2%. More contains only oxygen 49.7%, silicon 26% and aluminum 7.45%.
Mineral masses of which are economically advisable to extract metals or the necessary element are called ore fossil or ores. In accordance with this iron ores. They are called rock formations of which it is economically advisable to pay iron. The constant change in economic conditions due to the development of ore enrichment methods, the reduction in the cost of their transport changes the idea of \u200b\u200biron ore, since the lower limit of the iron content in it is decreasing all the time.
An industrial ore deposit is such a cluster of ore, which is economically appropriate to develop. The cost-effectiveness of this development increases with an increase in the power of the field, since to invest in construction for example mines or quarries, housing, communications, it is advisable only with sufficiently long-term operation of the deposit. Experience shows that the operation of the iron ore field is suitable and has a stable perspective with reserves of about 250-500 million tons.
Ore consists of ore and ore-forming mineral, empty breed and impurities. The recoverable element is in the ore mineral.
Iron ore ore minerals are oxides, iron carbonates and some other connections. The main one is described below.
It has the chic composition Fe 2 O 3 - anhydrous iron oxide. Hematite contains 70% iron. An formed ore hematite is called red Zheleznyak and is the most common type of ore. It is usually characterized by a high iron content and low content of harmful impurities. A typical field of hematitic ore is Krivoy Rog.
Picture 1 - General view of hematite mineral
It has the chemical composition of FE 3 O 4 - magnetic iron oxide containing 72.4% iron. It differs from other minerals of industrial iron ores by magnetic properties that are lost when heated over 570 o C. Magnetite is a mixed iron oxide Feo * Fe 2 O 3. The ores formed by magnetite are called magnetic railways or magnetites. They are less common than hematites are characterized by a high content of iron, reduced restraining, often accompanied by gray.
Figure 2. - Magnetite mineral type
Water oxides of iron - Fe 2 O 3 * NH 2 O - depending on the value of N form various types of oxides, but all ores formed by them are called brownie Zheleznyaki. The water oxides are distinguished:
- n \u003d 0.1 - hydrohematitis
- n \u003d 1 - Gett
- n \u003d 1.5 - lemonitis, etc.
Most often there are brownie zone based on limonite - 2fe 2 O 3 * 3H 2 O which are called limonite.
Brownie ironcles are characterized by a reduced iron content, loose, often accompanied by manganese, phosphorus, have high porosity and restority.
Figure 3. - Brown Zheleznyak based on Limonite
Siderite - It has the chemical composition of FECO 3 - iron carbonate. Contains 48.2% iron. An formed by a siderite of ore is called Psapadovaya Zheleznyak, or Sideress. With significant amounts of clay impurities can be called clay iron. Sidererites are spread much less than other ores. Characterized by high redundivity, low iron content due to its insignificant content in the ore mineral and large amounts of empty breed. Under the influence of moisture and oxygen, the atmosphere of the serifers can move into brown tapes, since iron (II) oxide in the FEO * CO 2 molecule is oxidized and absorbs moisture. Therefore, there are deposits in which the upper layers of ore are brownie transes, and the lower rooted siderites.
Figure 4.
It has the chemical composition of Fetio 3 - iron salt of titanium acid. Ilmenite contains 36.8% iron and 31.8% titanium. It is always found in fragments with ordinary magnetite, i.e. in the form of fetio 3 * Fe 3 O 4. Ilmenite ores are called titanomagnets.
Figure 5. - General view of Mineral Ilmenite
Titanoagnetitis is a dense harmful-state-owned ore, which gives thick and refractory titanium-containing slags. It has magnetic properties and is well enriched with magnetic separation. It is often accompanied by a bathroom.
FES 2 Iron sulfide in nature is WVID Mineral Pyrite or Sulfur Creek. It contains 46.6% iron. Pyrite iron ores do not form. It is used in the chemical industry, where it is burned for the sulfur separation. The iron is oxidized and in the form of pyrite flamers is used in the production of agglomerate.
Iron ores are rocks containing iron, and in such quantities that the ore is profitable. In nature there are about 20 minerals with a high content of iron (23-72%). Iron in ore is in the form of oxides or salts connected to rock. Depending on the state in which iron is located, there are four types of iron ores.
Brown Zheleznyak contains iron in the form of water oxide 2Fe2O3-3H2O. The color of the ore is yellow-brown. This ore is poor iron (from 35 to 60%), and sulfur and phosphorus, on the contrary, contains more than other ores. Ore is easily restored. Its largest deposits are located in the Urals (bakal ores with a high content of iron, almost without impurities of sulfur and phosphorus). Large reserves of brown railway in powder form are available on the Kerch Peninsula. Tula and Lipetsk deposits, Kola Peninsula, Togai iron ore basin are also known.
Red Zheleznyak contains iron as FE2O3 oxide. Ruda red, iron content 55-60%. This is one of the best iron ore; It is easily restored, contains little sulfur and phosphorus. The richest deposits of Red Zheleznyak are in Krivoy Rog. Large stocks of red Zheleznyaka are also available in the area of \u200b\u200bKursk magnetic anomaly.
Magnetic Zheleznyak contains iron as FE304 oxide. Rud black, iron content 45-70%. This is the richest ore iron. It has magnetic properties, dense, restored with difficulty. Locals mainly in the Urals - in the mountains magnetic, high, grace. Newly explored magnetic ironing deposits in the Togai steppe in Kazakhstan.
Pleight Zheleznyak contains iron in the form of salt FECO3. This ore is called seerite, or swamp ore. It is poor iron (from 30 to 45%). Rassoeing rails are found in the Urals in the Bakalsky deposit area
Complex iron ores contain, except iron, other metals (chromium, nickel, titanium, vanadium), rebelled in blasting melting:
chromonicel brown rails of Orsko-Khalilovsky deposit contain 35-45% iron; 1.3-1.5% chromium and 0.3-0.5% nickel;
titanoagnetites containing 42-48% iron; 0.3-0.4 / o vanadium and 4.5-13.0% of titanium dioxide are mined in the Urals in Kachkanar, Kusinsky and Pervouralsk deposits.
Manganese ores are used to increase the content of manganese in the flooded iron. These ores are soft, loose and hygroscopic. The content of manganese oxide in them is 28-40%. The most important deposit of rich ores (the content of manganese oxide is 48-52%) are Chiatur in the Caucasus, Nikopolskoye in Ukraine, at the city of Achinsk in Siberia, Uraloazovskoye and midnight in the Urals and Kazakhstan.
In the process of domain smelting, except for iron and manganese ores, use various waste: pig-iron scrap and chips, contaminated with steel scrap.
Fluses are used in blasting melting to fus a blank breed and fuel ash in slag. When the blast furnace furnaces on Coke is used mainly limestone (CACO3). If the basic oxides are located in a blank breed, acidic fluxes are used - quartzites.
Coke is used as a fuel for blast furnaces. Metallurgical fuel should have the following qualities: high calorific value, strength, porosity, low ash content and minimal sulfur content. Cox meets almost all of these requirements. The heat of combustion of coke 5600 kcal / kg, so 98% of the world cast iron is paid on it. Coke is obtained from stone coal when it is heated to 950-1000 ° without access in special furnaces. At the same time, volatile substances are removed from coal, and the remaining part is sintered into solid and porous coke.
Modern coke oven (battery) consists of 50-70 narrow long chambers with a capacity of 18-20 mV of each of them 12-16 tons of coke. The duration of the coking process is about 12-15 hours. From one ton of coal, you can get 750-800 kg of coke and 300-350 m3 of high-calorie gas.
The best coke is considered a Kuznetsky, containing 0.5-0.6% sulfur and 12-13.5% ash.
One of the most effective partial coke substitutes in blasting is natural gas. Its cost does not exceed 2 rubles. For 1000 l3, i.e., dozen times lower than the cost of coke.
The use of natural gas helps to reduce the cost of cast iron, as it saves from 10 to 15% of the coke.
5. Domain furnace device and its work
Blast furnace - Doma) is a mining furnace of continuous action. It has the shape of two truncated cones, folded by broad bases, between which there is a cylindrical part, called rake.
The cast iron is smelted from iron ores in special furnaces called domains. Hence the process of obtaining cast iron from iron ores is called a domain process.
The blast furnace has a large number of special devices and mechanisms that ensure the continuity of the process. Most mechanisms work automatically.
1-skip; 2-bouncing apparatus; 3-domain furnace; 4-fournilla holes; 5- cast-iron flyer; slag flyer; 7-air heaters; 8-gas cleaning devices; 9-smoke trumpet
The mixture of ore, coke and flux is prepared in a specific proportion to load into the blast furnace. This mixture is called the mixture. Special lift - Skip 1 moving along the inclined paths, delivers a mixture to the top of the blast furnace, where it comes from the falling unit 2 into the oven 3.
To maintain intensive burning of the loaded coke, a large amount of air is needed. Air is supplied to the furnace through special holes 4 at the bottom of the furnace, which is called fournem. In order for the air to break through the high post post and penetrated into all parts of the furnace, as well as that there was a sufficient amount of oxygen to combustion of all fuel, the air is blocked into the furnace under pressure in 1-2 ATI. The air is heated to a temperature of 600-800 °, since the blowing of a large amount of cold air reduces the temperature inside the furnace, as a result of which the process of melting ore slows down.
Air heating is carried out in air heaters 7, which are built next to the blast furnace. Air heaters are heated with a domain (cosherchnikov) gas, obtained when smelting cast iron. The domain gas is pre-cleaned from dust in special gas cleaning devices 8. Combustion products from air heaters are removed through the chimney 9.
The liquid cast iron obtained in the furnace is lowered into the lower part of it, from where it is periodically produced through a hole 5, called the cast-iron flyer. In the special lathes of the large capacity of cast iron from the blast furnace to be turned into steel-smelting goals for processing in steel or to a filling machine for cast iron saues.
Blank breed, fluxes and oola fuel form a liquid slag in the furnace, which has a smaller specific weight than cast iron, and therefore is located above the liquid cast iron. The slag is produced from the furnace through the slag flyer 6 and sent for processing and further use as a building material or slag.
The domain furnace is working continuously on the principle of countercurrent: the starting materials are loaded from above, gradually fall down, turning into cast iron and slag, and the gases heighted in the lower zone of the furnace are raised up to meet the source materials.
The furnace has an outer steel shell, which is called a casing, and inner masonry, or a lining. The lining should be stable to resist wear from friction of continuously descending submissions, withstand the action of high temperatures, not melting and not allowing deformations. Therefore, the lining is used high-quality refractory (chammatory) brick.
6. Production of steel in converters
Oxygen converter with upper purge. 1 - steel casing; 2 - refractory lining; 3 - oxygen truck; 4 - fuel filling; 5 - alloying additives; 6 - Letter; 7 - bucket; 8 - blank; 9 - wire; 10 - seamless pipe; 11 - Blum; 12 - beam; 13 - Tolstolic steel; 14 - sheet blank (slab); 15 - leaf rental.
The oxygen converter with an upper purge is a pear-shaped vessel (with an open narrow top neck) with a diameter of approx. 6 m and an ok height. 10 m, lined from the inside magnesian (main) brick. This lining is withstanding about 1500 melts. The converter is equipped with sidecases fixed in the supporting rings, which allows you to tilt it. In the vertical position of the converter of its neck is under an exhaust cap of the smoke fireplace. The side outlet existing on one side allows you to separate the metal from the slag during plum. In the converter workshop next to the converter usually there is a bootable span. It is transported here in a large bucket liquid cast iron from a blast furnace, and in steel bunkers accumulates scrap metal for loading. All this raw material is transferred to the bridge crane conversion. On the other side of the converter there is a casting span, where there is a receiving bucket for the fused steel and rail trolleys for transporting it to the casting platform.
Before the beginning of the oxygen-converter process, the converter is tilted towards the loading span and fall asleep across the neck. Then the liquid metal from a blast furnace containing about 4.5% of carbon and 1.5% silicon is poured into the converter. Pre-metal is subjected to desulfurization in the bucket. The converter is returned to the vertical position, the fury-cooled water is introduced on top and include oxygen supply. Carbon in cast iron is oxidized to CO or CO2, and silicon - to SiO2 dioxide. According to the "flow" (loading tray), lime for the formation of slag with silica dioxide is added. The slag is excreted to 90% of silicon contained in cast iron. The nitrogen content in the finished steel is greatly reduced due to the washing effect of CO. Approximately 25 minutes the blowing stops, the converter is slightly tilted, select the sample and analyze it. If necessary, you can return the converter to the vertical position again and enter the oxygen furma in the neck. If the composition and temperature of the melt correspond to specifications, the converter is tilted towards the casting span and the steel is drained through the outlet.
7. Obtaining steel in Mainen furnaces
The Moscow process was developed in 1865 by the French metallurgists by the father of E. Martin and the son of P. Martin. The Marten oven on the device and the principle of operation is a fiery regenerative furnace. In its smelly space, gaseous fuel or fuel oil is burned. The high temperature for the production of steel in the molten state is provided by the regeneration of the heat of the furnace gas. The working melting space of the furnace is limited to the bottom of the bathroom formed by pyro and slopes; from above - arch; From the sides - the front and rear walls; From the ends - heads. In the front wall there are windows through which the original embezzle is loaded into the oven and additional materials (along the melting), as well as take metal samples and slag, remove the slag during dephosphoriation. The windows are closed with flaps with inspection holes. Finished melting is released through a hole located in the rear wall at the lower level of the page. The hole is tightly clogged by small refractory materials.
For more complete use of exhaust gas heat in the system of gas feeds, regenerators are installed. Regenerators are made in the form of cameras filled with refractory bricks. The principle of heat regeneration lies in the fact that the nozzle of one pair of regenerators is heated for some time up to 1250 - 1300 OS gases separators from the furnace. Then, using valves, the direction of movement of the regenerators changes automatically. Through one of the heated regenerators, air is supplied to the working area of \u200b\u200bthe furnace, through the other - gas. Passing through the nozzle, they are heated to 1100-1200 C. At this time, another pair of regenerators is heated, accumulating the heat of the outgoing gases. After cooling the nozzles of regenerators, automatic switching valves occurs to the set temperature.
8. Obtaining steel in electric traits
Melting in electric traits has a number of advantages over melting in the converters and Mainens. High temperature allows you to use highly mining slags, introduce a large number of fluxes and achieve maximum removal of sulfur and phosphorus. For melting in the electric furnace, air is not required; The oxidizing ability of the furnace is low, so the amount of FEO in the bath is insignificant, the steel turns out quite stretched and dense. Due to the high temperature in the furnace you can get alloyed steel with refractory elements: tungsten, molybdenum, etc.
Source materials for smelting in electric hollows are steel scrap, iron ore, scale. The anconded Martin cast iron is used only for steels with high contents, but more often replaced with electrode battle or low-sized coke.
As fluxes in major furnaces, lime is used, and in acidic furnaces - quartz sand. For the liquefaction of the main slags, a fluctional sword is used, bauxite and chammatory battle, and for acidic slags - lime and chammatory battle. For deoxidation of steel, in addition to ordinary ferroalloys, complex deoxidizers are used (AMS containing 10% silicon, manganese and aluminum, silicanets, silicocallations).
All materials loaded into electric furnaces must be dry so that the saturation occurred is hydrogen from the expansion of moisture.
Electric furnaces for melting metal are divided into three types : Resistance furnaces, arc and induction.
For smelting steel used mainly arcs and induction furnaces, and in the sorrows of resistance they melt alloys of non-ferrous metal.
Arc furnaces N.aby more common in industry, since the device and operation of them are easy, the efficiency of the efficiency is high and, in addition, they can be paid in a wide variety of steel and alloys of non-ferrous metals. In arc furnaces, electricity turns into the thermal energy of an arc, which is transmitted by a melting mixture by radiation.
Induction furnaces It is used for the smelting of high-alloy steel and low carbon alloys, as well as for the production of thin-walled shaped casting with special methods (according to the models, under pressure, etc.).
Electroslak melting steel It is a completely new method for obtaining high-quality alloyed steels, including high-speed. It was developed by the Institute of Electric Welding. E. O. Patone of the Academy of Sciences of the Ukrainian SSR.
Its essence is that the ingots made of steel obtained in conventional furnaces are processed on the electrodes for the subsequent smelting of them in the electric shield furnace. Melting electrodes does not occur due to the heat of the electric arc, and due to heat released in the layer of the molten slag serving the resistance when the electric current is passed. The principle of electric shielding is very simple. The electrode-ingot 1 (Fig. 3) with a diameter of up to 150 mm and a length of 2 to B m is introduced into a copper water-cooled crystallizer 2, which is a hollow cylinder. By the bottom of the crystallizer is attached pallet 5 with seed 4 - this is a puck of overpanded steel. An electrically conductive flux of aluminum powder with magnesium poured on the seed. The gap between the fusion-electrode and the wall of the crystallizer is covered with a working flux 3 consisting of Al2O3, CAFE2 and CAO.
9. Progressive methods for obtaining steel
One of the progressive ways to produce complex and high-alloy steels is electrometallurgical: melting in electrical arc and induction furnaces.
Steel is particularly high quality in vacuum electrical furnaces, as well as by electric shielding, plasma overpare, electron beam smelting.
10. General information about metals. Classification of metals.
Metals - materials of crystal structures with a number of specific properties: metal glitter; high electrical conductivity and thermal conductivity; positive temperature coefficient of electrical resistivity; electronic emissions; Under normal conditions are in a solid state (exception is mercury).
In appearance, the metals are divided into black and colored. The ferrous metals include iron and alloys based on it, the remaining metals are customary to the color.
The ferrous metals used in the production of household goods are represented by two alloys: steel (iron alloy with carbon, with the content of the last no more than 2.14%) and cast iron (iron alloy with carbon, with the content of the latter more than 2.14%).
The cast iron is paid from iron ore in blast furnaces.
Steel is obtained from cast iron by burning out of it with an excess carbon with air oxygen.
11. Atomic-crystalline metal structure.
Under the atomic crystal structure understands the mutual arrangement of atoms that exists in a crystal. The crystal consists of atoms (ions) located in a certain order, which is periodically repeated in three dimensions.
In crystals, there is not only the neighbor, but also the long-range order of placement of atoms, i.e. the ordered arrangement of particles in the crystal is maintained at large sections of crystals. To describe the atomic crystal structure, use the concept of a spatial or crystal lattice.
The crystal lattice is an imaginary spatial grid, in the nodes of which atoms (ions) are located, forming the metal (solid crystalline body).
The smallest volume of the crystal, which gives an idea of \u200b\u200bthe atomic structure of the metal throughout the volume, was called the elementary crystal cell.
12. Properties of metals and alloys
Mechanical properties
The main mechanical properties include:
Strength
Plastic
Hardness
Strength - the ability of the material to resist destroying under the action of loads.
Plasticity - the ability of the material to change its shape and sizes by the action of external forces.
Hardness - the ability of the material to resist the penetration of another body into it.
Physical properties
Physical properties include:
Density
Melting temperature
Thermal conductivity
Electrical conductivity
Magnetic properties
Color - the ability of metals to reflect radiation with a certain wavelength. For example, copper has a pinkish-red color, aluminum - silver-white.
The metal density is determined by the mass ratio to a unit of volume. In density, the metals are divided into light (less than 4500 kg / m3) and heavy.
The melting point is the temperature at which the metal moves from the solid state into the liquid. The melting point is distinguished by refractory (tungsten - 3416 OS, tantalum - 2950 OS, etc.) and low-melting (tin - 232 OS, lead - 327 OS). In units, the melting point is expressed in degrees of Kelvin (K).
The thermal conductivity is the ability of metals to transmit heat from more heated parts of the body to less heated. Great thermal conductivity is silver, copper, aluminum. In units, thermal conductivity has the dimension W / (M · K).
The ability of metals to carry out the electric current is estimated by two opposite characteristics - electrical conductivity and electrical resistance.
The electrical conductivity is estimated in the system Siemens (cm). The electrical resistance is expressed in Omah (OM). Good electrical conductivity is necessary, for example, for cocked wires (they are made of copper, aluminum). In the manufacture of electric heating devices and furnaces, alloys are needed with high electrical resistivity (from nichrome, Constantane, manganin). With an increase in the temperature of the metal, its electrical conductivity decreases, and with a decrease - increases.
Magnetic properties are expressed in the ability of metals to magnify. High magnetic properties have iron, nickel, cobalt and their alloys, which are called ferromagnetic. Materials with magnetic properties are used in electrical equipment and for the manufacture of magnets.
Chemical properties
Chemical properties characterize the ability of metals and alloys to resist oxidation or enter into a compound with different substances: air oxygen, acid solutions, alkalis solutions, etc.
Chemical properties include:
Corrosion resistance
Heat resistance
Corrosion resistance - the ability of metals to resist chemical destruction under the action on their surface of an external aggressive medium (corrosion occurs when it comes into chemical interaction with other elements).
Heat resistance - the ability of metals to resist oxidation at high temperatures
Chemical properties take into account primarily for products or parts operating in chemically aggressive environments:
Capacities for the transport of chemical reagents
Chemical pipelines
Instruments and tools in the chemical industry
13. Concepts: alloy, component, phase, mechanical mixtures, solid solutions, chemical compounds.
Alloy is a macroscopically homogeneous metallic material consisting of a mixture of two or more chemical elements with a predominance of metal components.
Components - substances forming the system. Clean substances and chemical compounds are performed as components if they are not dissociated into components in the temperature interval under study.
The phase is a homogeneous part of the system, separated from other parts of the surface section of the system, during the transition through which the structure and properties change dramatically.
The mechanical mixture (in metal) is the structure of the alloy of two components, which are incapable of mutual dissolution in a solid state and do not enter into a chemical reaction with the formation of compounds. The alloy consists of crystals of components A and B
Solid solutions - phases of variable composition, in which atoms of various elements are located in the overall crystal lattice.
Chemical compound is a complex substance consisting of chemically related atoms of two or more elements (heteroantore molecules). Some simple substances can also be considered as chemical compounds if their molecules consist of atoms connected by covalent bond (nitrogen, oxygen, iodine, bromine, chlorine, fluorine, presumably ASTAT).
14. Crystallization of metals and alloys
The processes of crystallization of metals and alloys, which are processes of transition from a liquid state into solid, are associated with the release of hidden heat of crystallization. In order to take place the process of crystallization of a metal or alloy, it must be cooled all the time (all the time to delete it from it).
When considering crystallization processes, we first need to keep in mind a certain amount of liquid metal or alloy, which gives the heat and the shape that accepts it. The transfer of heat from the liquid metal and the alloy shaped is not instantly, since the thermal conductivity of the liquid metal or alloy and the form has certain end values. Therefore, the simultaneous crystallization of the entire volume of metal or alloy in the form is impossible even at the same temperatures in all points of its volume.
15. Experimental construction of dual alloys status diagrams
16. Rules of phases and segments
Phases may be liquid solutions, solid solutions and chemical compounds. Consequently, a homogeneous liquid is a single-phase system, a mechanical mixture of two types of crystals - a two-phase system, and so on.
Under the number of degrees of freedom (variability) of the system understand the number of external and internal factors (temperature, pressure and concentration), which can be changed without changing the number of phases in the system.
The quantitative relationship between the number of degrees of freedom of the system, which is in the equilibrium state, and the number of components and phases, is customary to be called the PAZ Rule (Gibbs Law). The phase rule for metal systems is expressed by the equation
C \u003d K - F + M,
where with - perception of degrees of system freedom; To-issue components; F - the number of phases; T - the number of external factors (temperature, pressure).
If we assume that all transformations occur at a constant pressure (p \u003d const), this equation will take the following form: C \u003d K - F + 1, where 1 is an external variable factor (temperature).
Using the rules of the phases, consider how the change in the number of degrees of freedom of one-component system is occurring for the case of a molten pure metal (K \u003d 1; F \u003d 1) C \u003d 1-1 + 1 \u003d 1, i.e. Temperature can be changed without changing the number of phases. Such a state of the system is called a monovariant (odnovantic). In the process of crystallization F \u003d 2 (two phases - liquid and solid), and K \u003d 1, then C \u003d 1-2 + 1 \u003d 0. This means that the two phases are in equilibrium at a strictly defined temperature (melting point), and it cannot be changed until one of the phases disappears. Such a state of the system is called non-invariant (unvavantized). For a diumponent system, which is in a liquid state (K \u003d 2; F \u003d 1), the phase rule has the form C \u003d 2-1 + 1 \u003d 2, such a system is called bivariant (dual-operating). In this case, two equilibrium factors (temperature and concentration) can be changed, the number of phases does not change. For the same system, with the existence of two phases (liquid and solid) K \u003d 2, F \u003d 2, according to the rules of phases C \u003d 2-2 + 1 \u003d 1, i.e. With a change in temperature, the concentration must be strictly defined.
Application of phase rules for the first type status diagram (see Fig.). Using this diagram, you can define the phase state of alloys of any composition at any temperature. For example, in region 1 there is one phase - a liquid solution. The phase rule is recorded in the form C \u003d K - F + 1 \u003d 2-1 + 1 \u003d 2, i.e. the system has two degrees of freedom. For the rest of the regions 2, 3, 4 and 5, the system is characterized by one degree of freedom (C \u003d 2 - 2 + 1 \u003d 1).
17. The status diagram of the alloys with a mechanical mixture
22. Structural components of iron carbon alloys
Ferrite - This is a solid carbon solution in α-gland. The maximum carbon concentration is only 0.025% (point P). At room temperature - not higher than 0.006%. Ferrite soft and plastic.
Austenit - solid carbon solution in γ-gland. Maximum carbon concentration - 2.14% (point E). Austenite has low hardness, plastic, not magnetic.
Cementite - Chemical compound of iron with carbon (iron carbide, FE3C). The concentration of carbon, respectively, constant is 6.67% of carbon. Cementite is very hard, fragile, default.
It is also necessary to distinguish 2 structural components of iron-carbon alloys:
Perlit (Euteteid) - a mechanical mixture of 2 phases - Ferrite and cement plates / grains. Perlite is formed as a result of the pearlite conversion of austenite ("free" or part of the Larbuerite) with a carbon concentration of 0.8% when passing below the PSK line:
A0.8 → F0,025 + Ts6,67
The iron is moving from the γ-form in the α-form. Mechanical properties are highly dependent on the size (dispersion) of the particles from which this perlite consists.
Larburt (eutectic) - Mechanical mixture of 2 phases - Austenite and cementite plates / grains. The iceburient is formed from a liquid phase with a carbon concentration of 4.3% when passing below the ECF line:
J4.3 → A2,14 + Ts6,67
The structure of the Larburita. C - cementite, A - Austenit.
23. Diagram of the state of alloys of iron cementite
Chart of iron-carbon (iron-cementitis) - This is a graphical mapping of the structure of alloys consisting only of iron and carbon, depending on the initial average concentration of carbon and the current alloy temperature. The iron-carbon chart allows you to understand the processes occurring during heat treatment of steel.
Chart of iron-carbon (iron cementitis). Simplified
aCD line. Liquidus line. When cooled alloys, their crystallization begins below it;
line AECF. Line Solidus. When cooled alloys below it, the entire alloy turns into a solid state;
eCF line. Sometimes it is called the line of the ice transformation. When cooled alloys with a carbon content above 2.14% below it, the liquid phase is converted into ice-drift;
pSK line. Line of pearlit transformation. When cooled alloys below it, the austenite turns into perlite.
Note several important points in the diagram:
point E. The point of maximum saturation of austenite carbon is 2.14%, at a temperature of 1147 ° C;
point P. Point of maximum saturation of ferrite by carbon - 0.025%, at a temperature of 727 ° C;
point S. Point "0.8% C-727 ° C" conversion of austenite with a carbon concentration of 0.8% per perlite (euteteid) of the same average concentration;
point C. Point "2.14% C-1147 ° C" of the conversion of a liquid with a carbon concentration of 2.14% in ice-lesome (eutectic) of the same average concentration.
\u003e "url \u003d" http://kazspecgeo.com/article/sostav-i-svoystva-zheleznoy-rudyi.html "\u003eHaving wondered - for which iron ore need it becomes clear that without it a person would not achieve the heights of the modern development of civilization. The tools of labor and weapons, details of cars and machines - all this can be made from iron ore. Today there is not a single branch of the national economy, bypass without steel or cast iron.
Iron refers to chemical elements widespread in the earth's crust. In the earth's crust, this element is practically not found in pure form, it is in the form of compounds (oxides, carbonates, salts and other things). Mineral compounds containing a significant amount of this element are called iron ores. Industrial use of ores containing in its composition ≥ 55% of iron is economically justified. Rudic materials with lower metal content are subjected to pre-enrichment. Methods of enrichment mining iron ores constantly improving. Therefore, at present, the requirements for the amount of iron in the composition of iron ore (poor) are constantly decreasing. ORD consists of compounds of a ore-forming element, mineral impurities and a blank breed.
- ores formed under the action of high temperatures are called magmatogenic;
- formed as a result of sedimentation at the bottom of the ancient seas - exogenous;
- under the action of extreme pressure and temperature - metamorphogenic.
The origin of the breed determines mineral mining conditions And in what form contains iron in them.
The main feature of iron ores is their widespread and very significant reserves in the earth's crust.
Main iron-containing mineral connections are:
- hematite is the most valuable source of iron, as it contains about 68-72% of the element and a minimum of harmful impurities, hematite deposits are called red iron;
- magnetite is the main property of the iron ore of this species - magnetic properties. Along with hematite is distinguished by iron content equal to 72.5%, as well as high sulfur content. Forms deposits - Magnetic Zheleznyaki;
- a group of metal metal oxides under the common name of the brownie zone. These ores have a low iron content, manganese impurities, phosphorus. This determines the properties of the iron ore of this type - significant reducibility, porosity of the structure;
- sideritis (iron carbonate) - features a high content of empty breed, the metal itself contains about 48%.
Application of iron ore
Iron ore is used to smear the cast iron, stailated cast iron and steel. However, before, the iron ore is used for its intended purpose, it is enriching at mining and processing plants. This refers to poor ore materials, the iron content in which is below 25-26%. Developed several methods for enriching poor ores:
- magnetic method, it consists in using the differences in the magnetic permeability of the ore components;
- flotation method using various wetting coefficients of ore particles;
- washing method that removes empty impurities with fluids under high pressure;
- a gravitational method applying special suspensions to remove a blank breed.
As a result of enrichment from iron ore, a concentrate is obtained containing up to 66-69% of the metal.
How and where iron ore and concentrates are used:
- ore is used in the domain production for the smelting of cast iron;
- to obtain steel by direct method, bypassing the stage of cast iron;
- to obtain ferroalloys.
As a result, profile and leaf rolling are made of the resulting steel and cast iron, of which then the necessary products are manufactured.
Wrote in July 26th, 2017
It rarely happens that I attend the same production twice. But when I was called me again on the Lebedinsky GOK and OEMK, I decided that you need to use the moment. It was interesting to see what has changed in 4 years since the last trip, moreover, this time I was more equipped and in addition to the camera, captured with me also the 4k camera in order to transfer you in reality the whole atmosphere, burning and fascinating personnel Since GOK and steel mills of the Oscolskoe Electrometallurgical Combine.
Today, it is specifically for a report on the extraction of iron ore, its processing, remelting and obtaining steel products.
The Lebedinsky GOK is the largest Russian enterprise for the extraction and enrichment of iron ore and has the world's largest iron ore mining quarry. The plant and quarry are located in the Belgorod region, not far from Gubkin. The company is part of Metalloinvest and is a leading manufacturer of iron ore products in Russia.
View from the observation deck at the entrance to the quarry fascinates. 
He is really huge and grow up every day. The depth of the leader of the Lebedinsky GOK is 250 m from the sea level or 450 m - from the surface of the Earth (and the diameter is 4 by 5 kilometers), underground water is constantly seeded, and if it were not for the work of pumps, he filled up to the very top for the month. He twice listed in the Guinness Book of Records as the largest quarry for the extraction of non-combustible minerals.
So it looks from the height of the spy satellite.
In addition to Lebedinsky GOK, Metalloinvest also includes Mikhailovsky GOK, which is located in the Kursk region. Together, the two largest plant are withdrawn to the world leaders in the mining and processing of iron ore in Russia, and in the 5-ki in the world for the production of commodity iron ore. The total explored reserves of these plants are estimated at 14.2 billion tons for the international classification of the JORS, which guarantees about 150 years of operational period at the current level of production. So the miners and their children will be allowed to work for a long time. 
The weather this time was also not solar, even the rains even frost, which was not in the plans, but from that photo came even more contrast). 
It is noteworthy that directly "in the heart" of the career is a plot with a blank breed, around which all the ore has already been produced. For 4 years, it has noticeably decreased, because this prevents the further development of the career and its systematically produce too. 
The iron ore is loaded immediately in the train composition, in special reinforced cars that take out the ore from the career, they are called dumpcars, their carrying capacity is 120 tons. 
Geological layers, which can be studied by the history of the development of the Earth. 
By the way, the top layers of a career, consisting of stone rocks that do not contain iron, do not go into the dump, and processed into crushed stone, which is then used as a building material. 
Giant machines from the height of the sightseeing site seem no more than ant. 
On this railway, which connects the quarry with the factories, the ore is transported for further processing. The story will be next. 
A lot of all kinds of equipment works in the quarry, but the most noticeable, of course, is the multi-dump trucks "BelAZ" and "Caterpillar". 
By the way, these giants have the same car numbers as ordinary cars and they are registered with the traffic police. 
In the year, both mining processing plant included in Metalloinvest (Lebedinsky and Mikhailovsky GOC) produce about 40 million tons of iron ore in the form of a concentrate and aglorud (this is not the amount of production, but an already enriched ore, that is, separated from the empty breed). Thus, it turns out that on the day on two Goks, about 110 thousand tons of rich iron ore is produced.
This Bellase is at a time transporting up to 220 tons of iron ore. 
The excavator gives a signal and it gently gives reverse. Just a few cumshots and giant body filled. The excavator once again gives a signal and the dump truck away.
This excavator "Hitachi", which is the largest carpet of the bucket capacity of 23 cubic meters. 
BelAZ and Caterpillar alternate. Imported dump truck transports only 180 tons. 
Soon the driver of "Hitachi" will be interested in this breast. 
Interesting texture at iron ore. 
1-day in the career of the Lebedinsky GOK employs 133 units of the main mining equipment (30 heavy dump trucks, 38 excavators, 20 bustracks, 45 traction aggregates). 
Bellase beds 
The explosions could not be seen, and rarely when the media or bloggers are allowed for them because of the safety standards, such an explosion is made once every three weeks. All equipment and security workers are excluded from the career before. 
Well, then the dump trucks unload the ore closer to the railway right there in the career, from where other excavators overload it to Dumpcars, which I wrote above. 
Then the ore is carried to a processful factory, where ferrous quartzites are crushed and the process of separating the empty breed by the magnetic separation method: the ore is crushed, then they are sent to the magnetic drum (separator), to which, in accordance with the laws of physics, all iron sticks, and not iron - washed off water. After that, from the resulting iron ore concentrate, pellets and GBH are made, which is then used for steel smelting.
In the photo mill, grinding ore. 
In the workshops there are such hooks, after all, it is hot here, and without water in any way. 
The scale of the workshop where the ore is impressive in the drums. Ore is griming naturally when the stones are fighting each other in the process of rotation. About 150 tons of ore are placed in the drum with a semenster diameter. There are 9-meter drums, their performance is more almost twice as well! 
I went for a minute to the workshop control panel. It is quite modest here, but the voltage is felt immediately: the dispatchers work and control the workflow on the control panels. All processes are automated, so any intervention - whether it stops or starting any of the nodes through them and with their direct participation. 
The next point of the route became the complex of the third stage of the workshop for the production of hot-chicted iron - CGBG-3, on which you already guessed, a hot-barked iron is produced. 
The production capacity of the CGBG-3 is 1.8 million tons of products per year, the total production capacity of the company, taking into account 1 and 2 of the production capacity of the GBW, has grown cumulatively up to 4.5 million tons per year.
The CGBG-3 complex covers an area of \u200b\u200b19 hectares, and it includes about 130 facilities: the strokes of the charge and the product, the paths and transportation of oxidized pellets and finished products, the system of dedusting the lower sealing gas and the GBW, pipelines, the reducing station of natural gas, station Sealing gas, electrical substations, reformer, process compressor and other objects. The mine furnace herself is 35.4 m high, is placed in an eight-tier metal structures with a height of 126 meters.
Also, within the framework of the project, both the concomitant industries of the processing factory and the occupation factory were also carried out, which provided the production of additional volumes of iron ore concentrate (iron content of more than 70%) and highly internationally increased quality.
The production of GBW today is the most environmentally friendly method of obtaining iron. In its production, harmful emissions are not formed associated with the production of coke, agglomerate and cast iron, and there are also no solid waste in the form of slag. Compared to the production of cast iron, energy consumption for the production of GBW is lower by 35%, greenhouse gas emissions are 60% below.
GBW is produced from the pellets at a temperature of about 900 degrees.
Subsequently through the mold or as it is also called "briquette-press" formed iron briquettes.
This is how commodity products looks like:
Well, now we are shooting a little in hot shops! This is an OSCC electrometallurgical plant, simply speaking OEMK, where steel melts. 
Closely suitable, the heat is feeling noticeable. 
On the upper floors, hot, rich with iron soup is stirred by a half. 
They are engaged in this heat-resistant steelovers. 
Slightly missed the moment of iron pouring into a special container. 
And this is already ready-made iron soup, please feel the table until you cooled. 
And one more is the same. 
And we go further on the workshop. In the figure you can see the samples of steel products that produce the plant. 
Production here is very textured. 
In one of the workshops of the plant, such steel blanks are produced. Their length can reach from 4 to 12 meters, depending on the desire of customers. In the photo 6-stream machine continuous casting of blanks. 
Here you can see how the blanks are cut into pieces. 
In the next workshop, hot blanks are cooled to water to the desired temperature. 
And so there are already cooled, but not yet processed products. 
This is a warehouse where such semi-finished products are placed. 
And these are multi-torque, heavy shafts for iron rental. 
In the adjacent shop, OEMK is calculated and polished steel rods of different diameters, which have passed hire in previous shops. By the way, this plant is the seventh largest enterprise in Russia for the production of steel and steel products. 
After polishing the products in the next workshop. 
Another workshop, there is a snap and polishing of products. 
So they look in untreated. 
Folding polished rods together. 
And storage with a crane. 
The main consumers of metal products of the OEMK in the Russian market are enterprises of automotive, machine-building, tubular, metician and bearing industries.
Like folded neat steel rods). 
OEMK applies advanced technology, including the technology of direct iron reduction and electric melting, which ensures high-quality metal, with a reduced impurity content. 
OEMC metal products are exported to Germany, France, USA, Italy, Norway, Turkey, Egypt and many other countries.
The plant manufactures products used by leading world automakers, such as Peugeot, Mercedes, Ford, Renault, Volkswagen. Of them make bearings for these most foreign cars. 
At the request of the customer, the sticker is glued to each product. On the sticker, the melting number and steel brand code. 
The opposite end can be marked with paint, and tags with a contract number, destination countries, steel grade, smelting rooms, size in millimeters, names of the supplier and weight of the package are attached to each package. 
Thank you for reading to the end, I hope you were interested.
Special thanks for the Campaign "Metalloinvest" for the invitation!
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