RU2492246C2 - Method of producing ferrous metals - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method of making ferrous metals in liquid, pasty and solid form exploits the magnetic activity of metal heated to 650-860°C of iron-ore.

EFFECT: higher efficiency of processing roasting-magnetic concentrate at pyrometallurgy plants.

10 cl, 4 dwg

Description

The invention relates to the field of ferrous metallurgy, in particular to a pyrometallurgical redistribution of brown iron ore ores of an oolitic structure.

The current state of the raw material supply of the needs of existing metallurgical plants is characterized by the depletion of reserves of iron-rich and free of harmful impurities ores. This circumstance stimulates the development of technologies for the involvement of multibillion reserves and resources of brown iron ore ores of the oolite structure in the composition of iron ore.

Geological and technological research of Kerch (Ukraine), Lisakovsky and Ayat (Kazakhstan), Bakchar (Russia) brown iron ore showed that these ores, with an iron content of 25-45% Fe, contain large amounts of vein minerals, phosphorus, and alkaline elements. Such natural features of the initial product require additional procedures during the pyrometallurgical redistribution of raw materials to enrich it with a useful component and to free from harmful impurities that impair the processing and quality of the resulting products.

One of such additional procedures, tested at the stages of research, experimental and pilot industrial work on all natural types of ores mentioned above, is the technology for producing firing-magnetic concentrate (OMK). To date, no universal scheme for the implementation of this technology has been proposed, even for one natural type of ore (see, for example: Parfenov AM, Yudenich T.I. Enrichment and agglomeration of ayat brown iron ore // Oolitic brown iron ore of the Kustanai region and ways to use them. / Edited by I.P. Bardin. - M.: Publishing House of the USSR Academy of Sciences, 1956. - p.149-188; K. Zhunusova, A.A. Mukhtar, M.K. Alzhanov, and Kim V.A. The use of various analysis methods to identify the behavior of brown iron ore ores of the Ayat deposit during firing-mannite beneficiation / Enrichment ore, No. 6, 2009). This situation is explained by the changing requirements for a “good” economy, ecology, the quality of the products of the pyrometallurgical redistribution, as well as the problem of the similarity of properties and structure of fused iron-containing and vein minerals inherent in all natural types of brown-iron ore of the oolitic structure.

The specific manifestations of all the difficulties in obtaining ferrous metal during pyrometallurgical redistribution according to the sintering scheme of brown iron ore of an oolitic structure can be illustrated by the experience of Kazakh enterprises - Lisakovsky Mining and Processing Plant (LisGOK) and Karaganda Metallurgical Plant (KarMK).

Since 1975, the main iron ore base of KarMK has been the Lisakovskoye deposit of brown iron ore (Kazakhstan, Kustanai region). For LisGOK, the Mechanobr Institute and a number of other research and industrial enterprises carried out work on the development and selection of Lisakovsky ore dressing technologies. Based on the results of technical and economic calculations, a scheme of gravitational magnetic enrichment was chosen. Until 1994, the Lisakovsk Gravitational Magnetic Concentrate (LGMK) was the basis of KarMK’s raw material base, which produced about 9.8 million tons of fluxed sinter using 5.3 million tons of LGMK and 3.0 million tons of unenriched iron ore from the Atasuisky GOK.

For the redistribution of iron ore raw materials were used: sinter plant No. 2 (LGMK share 80-85%); blast furnaces No. 3 and No. 4 (the proportion of sinter agglomerate No. 2 95-98%); Cast iron with a phosphorus content of more than 1.0% was processed by 300-ton converters.

To select the optimal depth of enrichment of Lisakovsky raw materials for pyrometallurgical redistribution at KarMK, at the suggestion of research and design organizations, it was decided to develop a pilot-industrial technology and construct pilot-firing magnetic beneficiation plants at LisGOK producing Lisakovsky firing-magnetic concentrate (LOMK).

A pilot industrial plant for firing magnetic enrichment using a step-weighted layer (SHS-1.0) as a heat unit of the furnace worked from 1975 to 1992. The design capacity of the crude ore plant is 1 million tons per year.

During this period, 7 million tons of raw ore were processed and 3 million tons of LOMK were produced with an iron content of 61.8%; silica - 5.4%; alumina - 5.8%; phosphorus - 0.85%. Until 1991, the installation worked cost-effectively. With an increase in fuel and energy prices, LisGOK was forced to stop its operation, as the production of LOMK became unprofitable.

Experimental melts conducted by KarMK using LOMK showed that together with an increase in the iron content, an increase in the alumina content occurs (in blast furnace smelting to 19.0-22.6%). This fact causes problems in the development of smelting products. But, in principle, the possibility of processing this type of material has been proven. In the period from 1981 to 1985, KarMK produced industrial melts of LOMK prepared for the blast furnace process using various agglomeration methods (KarMK agglomerates, autoclaved pellets of LisGOK; fired pellets of the Sokolovsko-Sarbaisky GOK).

During the period from 1975 to 1995, LisGOK, together with a number of research institutes of the USSR, carried out a series of research works to improve the processing technologies of LGMK and LOMK. The aim of these works was to overcome the main disadvantages of the metallurgical redistribution of Lisakovsky iron ore:

- low iron content, increased alumina and phosphorus, strongly associated with hydrogetite;

- high hygroscopic and hydrated moisture content (for LGMK);

- poor clumping and low gas permeability of the concentrate layer;

- increased fuel consumption in the sinter and blast furnaces;

- increased consumption of lime, high iron loss, low durability of converters, reduced yield in the converter shop.

The above disadvantages of Lisakovsky raw materials led to a 20-25% increase in the cost of steel produced at KarMK compared to other metallurgical enterprises of the USSR. Under the conditions of a planned economy and stable energy prices, KarMK phosphor cast iron was smelted into steel at fixed costs.

Technical and economic calculations performed according to the results of R&D showed that LOMK cannot compete with iron ore raw materials obtained from natural magnetite ores. According to the Institute “GIPROMEZ” (Moscow), the above costs for the production of LOMK exceeded 1.5 times the permissible value. The main component of the costs was represented by energy costs and fuel, which accounted for more than half of all production costs. Unit costs per 1 ton of LOMK amounted to: natural gas - 71 cubic meters; coal - 200 kg; electric power 110 kWh

Since 1992, LisGOK supplies KarMK only LGMK.

During the formation of a market economy, there was a significant decrease in the consumption of LGMK in the sintering furnace charge to 100-120 thousand tons per month (with the production capacity of LisGOK up to 400 thousand tons per month).

This reduction in the demand of LGMK to the level of economic feasibility - 20-30% in the iron ore part of the blast furnace charge under the single-slag mode of steel smelting in the converter shop is due to the technical and economic indicators of the converter redistribution depending on the share of LGMK in the charge. It turned out that with an increase in the share of LGMK from 23 to 80%, the indicators change as follows:

- cast iron consumption per ton of steel increases from 825 to 840 kg;

- the yield decreases from 89 to 85.5%;

- the output of converter slag increases from 150 to 250 kg per ton of finished steel;

- lime consumption increases from 58 to 115 kg / t;

- 2 times increases the consumption of refractories for lining;

- oxygen consumption increases from 63 to 70 m ³ / min.

Currently, the Lisakovsky concentrate for sintering redistribution is obtained according to a combined scheme - gravity separation with a yield of concentrate of 30-35% and an iron content of 48-49% Fe followed by reduction firing, magnetic separation and gravity tails.

This scheme reduces operating costs, but does not solve such problems as, for example, the problem of increasing the alumina content in blast furnace slag, which, with a high sulfur input with other iron ore materials, reduces the possibility of producing high-quality cast iron.

An analysis of forty years of experience in the pyrometallurgical redistribution of Lisakovsky ores gives grounds to draw attention to the possibility of more efficient application of the non-redistributed redistribution of the oyolitic ayat and Bakchar brown iron ore intended for industrial development.

According to the chief agglomeration manager AMST (formerly KarMK) in 2003-2006. Borisenko V.A. regarding the prospects for the use of Bakchar iron ore raw materials “despite the positive experience of KarMK in the processing of this raw material in sintering, the best effect can be achieved in the production of highly iron metallized materials, provided that phosphorus and iron are separated when oolites are destroyed, and slag-forming is separated into a separate phase with absorption phosphorus. The resulting product in the form of pellets, briquettes or granules can be used in electric furnaces for the production of steel. Judging by the literature data and the metallurgical properties of iron ore, the process of solid-phase reduction after the preliminary dehydration of hydrogetite is most suitable for this. "

Metallurgist Michiel Freislich, a representative of the Australian company NATN, specializing in the design of metallurgical industries, also considers the introduced redistribution of Bakchar ore (according to the scheme: beneficiation - pellets - direct-reduced iron - electric arc furnace) the most optimal option for the implementation of the Bakchar project (private communication, Tomsk, Tomsk mining mining company, 2007).

Technical solutions are considered in more detail in the work Technological problems and prospects for the development of the Bakcharsky manifestation of iron ores / Collection of articles devoted to the 50th anniversary of the opening of the West Siberian iron ore basin and the Bakcharsky manifestation of iron ores // Comp .: V.I. Lunev. Under the general ed. V.G. Emesheva, M.S. Parovinchak; scientific Ed .: V.I. Lunev, A.I.Usenko. - Tomsk: LLC NPO TomGDKruda, 2008. - 386 p. - Hands. Dep. at the Moscow State University Depository. - Information No. 654109-08 from 06/30/2008.

The opinion of experts that has been strengthened in recent years about the advisability of using the introduced pyrometallurgical redistribution of brown oolitic iron ore is a new trend in ferrous metallurgy (see, for example, in the forty-year retrospective, sources: Extrasystemic production of iron abroad. - M., 1964; Metallurgical mini-plants / Smirnov A.N., Safonov V.M., Dorokhova L.V., Tsuprun A.Yu. - Donetsk: Nord-Press Publishing House, 2005).

Taking the above-mentioned methods for sintering redistribution of Lisakovsky, Ayatsky, Bakcharsky brown iron-ore ores of the oolitic structure into ferrous metal as analogues, we use patent RU 2402499 as a prototype, where on page 8 and Fig. 7 of the description of the invention information is given on the use of cooled calcined magnetic concentrate ( OMK) according to the scheme of introduced pyrometallurgical redistribution.

According to the prototype, oolites are revealed during the joint high-temperature roasting of ore and clinker minerals, are melted to form ore-clinker specs, in which ore vein minerals and phosphorus become part of the clinker material, then the specs are cooled to temperatures of 650-860 ° С, crushed, and the grinding is separated by magnetic separation into clinker and ore concentrate, the concentrate is cooled, crumpled into pellets, granules or hot briquetted iron (HBI), from which directly reduced iron (DRI) and steel are obtained.

The task is to increase the efficiency of using OMK in the pyrometallurgical redistribution of brown-iron ore of the oolitic structure according to the introduced scheme.

The problem is solved by using the magnetic-thermal potential of physical fields formed in the process of ore roasting and controlled cooling of OMK. The heating and magnetization of OMK intensify the course of pyrometallurgical processes due to a more accurate and faster introduction of OMK into the active zone of the process, high-speed heating of OMK in the core, introduction of physical heat into the process, and reduction of costs for the process of energy carriers and materials.

According to claim 1 of the invention, OMK purified from vein minerals and harmful impurities is fed into the pyrometallurgical process in a form heated to 650-860 ° C, where, under the force of magnetic fields of pyrometallurgical plants in the active zone, it undergoes targeted metallurgical changes: it is converted into liquid metal (steel); pasty metal (critsu); solid hot briquetted iron (HBI) and direct reduced iron (DRI). If necessary, to obtain steel, in addition to OMK, kritu, HBI, DRI are used, and when receiving the krit, HBI is added.

According to claim 2, the ferrous metal is obtained in liquid form by supplying OMK to the arc burning zone of an electric arc steelmaking furnace.

According to claim 3, the ferrous metal is obtained in a pasty form (in the form of crits or critical iron) by supplying OMK to an induction crucible.

According to claim 4, the ferrous metal is obtained in solid form in the form of hot briquetted iron (HBI) by supplying OMK to a briquette press with magnetically active molds.

According to claim 5, the ferrous metal in liquid form is obtained by additional supply to the electric arc steel furnace of critical iron heated to temperatures of 1250-1350 ° C.

According to claim 6, ferrous metal in liquid form is obtained by additionally supplying hot briquette iron (HBI) heated to temperatures of 650-860 ° C to the electric arc steel furnace.

According to claim 7, ferrous metal in liquid form is obtained by feeding hot OMK heated to temperatures of 750-860 ° C, hot briquetted iron (HBI) heated to temperatures of 750-860 ° C and obtained from hot OMK into an electric arc steelmaking furnace, hot critical iron heated to temperatures of 1250–1350 ° C and obtained from hot OMK.

According to claim 8, ferrous metal in the form of cryogenic iron is obtained by additional supply of hot briquette iron (HBI) to an induction furnace heated to temperatures of 750-860 ° C.

According to claim 9, the solid metal is obtained in solid form by treatment by forging or pressing in a reducing medium of critical iron at a temperature of 1250-2350 ° C.

According to claim 10 of the invention, ferrous metal in liquid form is obtained by supplying hot briquette iron (HBI) to a magnetically active reduction shaft furnace, heated to temperatures close to the Curie point for iron, and, if necessary, pellets, obtaining directly reduced iron from HBI and pellets (DRI) and feeding DRI, possibly in conjunction with HBI, to a steelmaking electric furnace.

Consider in more detail the implementation of the above options for a method of producing ferrous metal.

A retrospective analysis of the history of the issue (see, for example: Tatsienko P.A. Preparation of refractory iron ores. - M .: Nedra ,, 1979; Tatsienko P.A. Ore and concentrate roasting. -M .: Nedra, 1985; Yusfin Yu. S., Gimmelfarb A.A., Pashkov N.F. New methods for producing metal. - M .: Metallurgy, 1994; Kurunov I.F., Savchuk N.A. Status and perspective of homeless iron metallurgy. - M .: Chermetinformation , 2002) showed that such key participants in the pyrometallurgical technology as iron ore and its processing plants can be simultaneously in magnetoactivity Willow states. Thus, it is possible to use the property of electromagnetic interaction of magnetoactive raw materials and a magnetoactive installation to influence the course and result of the pyrometallurgical process in order to increase its efficiency.

где $$\overrightarrow{H}$$

- вектор напряженности магнитного поля, µ - магнитная проницаемость. Магнитная индукция определяет силу действия на частицу - силу Лоренца $$\overrightarrow{F}$$

. Магнитная часть силы Лоренца $$\overrightarrow{F}~[\overrightarrow{V}\times \overrightarrow{B}]$$

, где $$\overrightarrow{V}$$

-вектор скорости движения частицы в силовых линиях внешнего магнитного поля.The nature of magnetism is well studied (see, for example, Vonsovsky S.V. Magnetism. - M., 1971). Magnetism is caused by a magnetic field - a force field acting on particles that have a magnetic moment. The magnetic field is characterized by a magnetic induction vector, $$\overrightarrow{B}=\mu \overrightarrow{H},$$

Where $$\overrightarrow{H}$$

is the vector of the magnetic field strength, μ is the magnetic permeability. Magnetic induction determines the force of action on a particle - the Lorentz force $$\overrightarrow{F}$$

. The magnetic part of the Lorentz force $$\overrightarrow{F}~[\overrightarrow{V}\times \overrightarrow{B}]$$

where $$\overrightarrow{V}$$

-vector of particle velocity in the lines of force of an external magnetic field.

и $$\overrightarrow{B}$$

, омагниченные частицы ОМК будут «кружить» вокруг силовых линий внешнего магнитного поля и, как все ферромагнетики, смещаться в ту точку магнитного поля, где его напряженность максимальна $$\overrightarrow{H}=\max$$

, то есть будут локализоваться в том месте магнитного поля, где силовые линии «гуще». Как правило, силовые линии внешнего магнитного поля «сгущены» в активных зонах пирометаллургического процесса.In pyrometallurgical plants, a changing electric field induces an external magnetic field with respect to iron ore particles, and makes the plants magnetically active. OMK particles at a temperature of 650-860 ° C are close to the second-order phase transition, characterized by a Curie point for iron θ _Fe = 770 ° C, are magnetized, that is, they also become magnetically active. Depending on the angle between $$\overrightarrow{V}$$

and $$\overrightarrow{B}$$

magnetized OMC particles will “circle” around the lines of force of an external magnetic field and, like all ferromagnets, will shift to that point of the magnetic field where its intensity is maximum $$\overrightarrow{H}=\max$$

, that is, they will be localized in that place of the magnetic field where the lines of force are “thicker”. As a rule, the lines of force of an external magnetic field are “thickened” in the active zones of the pyrometallurgical process.

Modern out-of-house circuits are implemented on the basis of metallurgical mini-factories with steel-smelting electric arc furnaces, in which the area of combustion of the electric arc column is the magnetically active zones of the pyrometallurgical process. The electric arc in melting furnaces, both of direct type of action (“cathode-electrode” - “anode-melt”), and in furnaces of indirect type of action (“cathode-electrode” - “anode-electrode”), can be characterized as thermoelectronic with high current density - up to 10 ² -10 ³ A / mm ² . With characteristic diameters of graphite electrodes of 100-200 mm, the arc currents can reach 1-40 MA, generating a powerful magnetic field around the arc column.

A fact is known from practice that in electric arc welding of ferroalloys, the arc deviates from its normal position in the direction of the magnetic material. This is because the magnetic lines of force surrounding the electric arc tend to close along the line of least resistance, that is, through the ferromagnetic mass. Between the welding arc and the ferromagnetic mass, an electromagnetic attractive force appears, which deflects the arc in the direction of the ferromagnetic mass.

A similar physical phenomenon will be observed during the interaction of the magnetic field of the electric arc in the melting furnace with the hot firing-magnetic concentrate (OMC) fed into the arc zone.

As a result of this phenomenon, the concentrate particles will be drawn into an arc discharge, melt, and drop into the furnace bath.

It should be noted that the magnetic induction B at a distance R from the arc column with current J is directly proportional to J, the magnetic permeability µ of OMC particles and inversely proportional to R: B ~ µJ / R. When OMC particles with μ >> 1 get into the zone of the arc column (retraction of a ferromagnet), they instantly cross the Curie when heated, become para-magnets with μ≥1, but in an inhomogeneous strong magnetic field they continue to be drawn into the region of higher magnetic field strength.

The tendency to minimize the cost of raw materials and energy, whose share in the production of electric steel exceeds 70%, is the main direction of the development of equipment and technology for smelting in an electric arc furnace.

Currently, the raw material structure for steelmaking electric arc furnaces is characterized by the ratios of steel scrap: (DRI + HBI): cast iron = 12: 3: 1 [Metallurgical mini-plants / Smirnov AN, Safonov VM, Dorokhova LV , Tsuprun A.Yu. - Donetsk: Ed. "Nord Press", 2005, from 165-173].

The above version of the method for producing ferrous metal in liquid form by supplying OMK to the burning zone of the arc column of a steel-smelting electric arc furnace can, in our opinion, provide a partial (25%) alternative to steel scrap while reducing energy consumption to 400 kW * hour per heat.

It is known that replacing 1% of steel scrap with cast iron allows introducing from 1.1 to 4.3 kW * h / t of additional energy into the steel melting process of an electric arc furnace.

Ultimate pig iron as a charge material has a significant energy potential due to the high content of carbon and silicon.

The use of liquid iron in the filling is energetically beneficial not only because of the release of additional chemical energy from the oxidation reactions of C, Si, Mn (up to 2.5 kW * h / t), but also the introduction of physical heat into the bath. The temperature of liquid cast iron before pouring into the furnace is 1150-1350 ° C, while its heat content reaches 223-272 kW * h / t. With a smelting mass of 165 tons, the economically optimal amount of molten iron in the charge is about 30% [Metallurgical mini-plants / Smirnov AN, Safonov VM, Dorokhova LV, Tsuprun A.Yu. - Donetsk: Ed. "Nord-Press", 2005, p.169-172]. The use of a large number of pig iron in the production of bulk steel can lead to an increase in the cost of finished steel due to the need for additional decarburization and an increase in the consumption of slag-forming materials.

In order to add up the advantages of solid and liquid cast iron in a charge of a steelmaking electric arc furnace, it is proposed to use dough-like critical iron (kritz) obtained by heating OMK in an induction crucible furnace. Crucible furnaces are used to produce liquid steels and alloys when heat is released in the heated metal itself, and is not supplied from local external heat sources. In this case, the inductor generates a magnetic field, a significant part of the lines of force of which is closed above the crucible through the air, forming a "entrance" to the magnetically active zone of the pyrometallurgical process. OMK is supplied to this “input”, the magnetic charge is heated both due to Joule heat and due to heat losses during magnetization reversal of particles after the Curie point transition. The starting heating of the magnetic charge occurs at a faster rate than the starting heating of the non-magnetic charge due to the greater power consumption and higher heat concentration in the material.

The conglomerates of OMK particles soften, sinking to the bottom of the crucible, and stick together in a pasty mass-matrix at a temperature of 1250-1350 ° C.

By adding to the composition of the charge of the steelmaking electric arc furnace in the optimum volume a curve with a heat content of 270 kW * h / t and a carbon content in the range of 0.2-1.0%, it is possible to reduce electricity consumption to 15 MW * h for melting with a melting mass of 150-180 t

In addition, by forging (pressing) red-hot krita in a solid carbon reducing agent medium, a metal with 99.72% Fe having the corrosion resistance of noble metals can be obtained.

One of the disadvantages of using steel scrap in steelmaking electric arc furnaces is the uncontrolled content of residual contaminants (copper, chromium, nickel, tin, molybdenum, zinc), which determines the possibility of fulfilling the requirements for the chemical composition of finished steel. So, for example, at one of the CIS plants, when melting in an electric arc furnace, the following average values of non-ferrous metal impurities in ladle samples of melts melted using 100% scrap were obtained: Сu - 0.20%; Ni - 0.16%; Cr - 0.08%; Sn - 0.012% [Metallurgical mini-factories / Smirnov A.N., Safonov V.M., Dorokhova L.V., Tsuprun A.Yu. - Donetsk: Ed. "Nord-Press", 2005, p.166-168]. To reduce the content of non-ferrous metals in the finished steel, along with scrap metal, alternative iron-containing charge materials, metallized raw materials, are introduced into the charge of electric arc furnaces. Typically, the metallization degree of such raw materials — hot briquetted iron (HBI) and direct reduced iron (DRI) — reaches 92-93%. The main producers of metallized raw materials are Venezuela, Trinidad, Iran and Mexico. The introduction of HBI and DRI into the working space of the furnace is carried out, as a rule, during melting. DRI can also be fed into the filling in a heated (550 ° C) state [Metallurgical mini-plants / Smirnov AN, Safonov VM, Dorokhova LV, Tsuprun A.Yu. - Donetsk: Ed. "Nord-Press", 2005, p.170].

It is proposed to obtain ferrous metal in solid form in the form of HBI and DRI, using the magnetoactive properties of raw materials and their processing plants, and then to obtain ferrous metal in liquid form (steel), melting HBI and DRI.

To obtain HBI, drum-type briquette presses with magnetized molds are used. The bottom of the mold is magnetized by means of a solenoid (see, for example, Montgomery B. Obtaining strong magnetic fields using solenoids / Transl. From English - M., 1971) during the arrival of heated OMK and, if necessary, binders additives.

The toroidal force lines of the mold capture OMK particles, filling the mold volume from its bottom to the top, the punch compresses the filled volume, giving the briquette a given shape. After completing the OMK pressing, the movable solenoid armature connected with the movable bottom of the mold pushes the briquette out of the mold and, with the magnetic field turned off, the briquette leaves the briquette press. The pressing process is calculated so that the resulting HBI retains the magnetically active properties of OMK at a temperature of 650-860 ° C. This is achieved by observing the heat balance during briquette pressing by equalizing the heat transfer of the pressed material by the walls of the mold and the punch and the heat input from the OMK compression process.

Obtained by the described method, HBI can be supplied in hot form both for further metallization, for example, using MIDREX technology, and for producing steel in an electric arc furnace.

Due to the fact that the iron content of OMC, pellets, HBI, obtained from brown iron ore ores of the oolitic structure according to patents RU 2402499 and RU 2458158 and the above method, will not achieve the desired (92-93% Fe), it is advisable to obtain DRI. To do this, a magnetically active shaft furnace with a blowing gas is used. For filling the furnace, HBI heated to a temperature of 650-860 ° C or heated HBI with pellets is used. The shaft furnace is equipped with magnetic field inductors, for example, used for electromagnetic mixing of molten steel (US 4294435, RU 2157492), which provide “tedding” of HBI in the flow of a blown reducing gas (natural gas, hydrogen, carbon monoxide). This allows you to increase the speed and depth of penetration of the reducing agent into pelletized raw materials, to increase the efficiency of its metallization. The physical heat introduced by heated HBI into the pyrometallurgical process also increases its efficiency by saving energy.

The figures in Figs. 1-4 schematically explain the interaction of magnetically active iron ore (OMC, HBI) - item 1 with the magnetically active zones of pyrometallurgical plants - item 2 when receiving ferrous metal - item 3 in a liquid state on a steel-smelting electric arc furnace - figure 1 ; in a pasty state in the form of critical iron (kritza) on an induction furnace - figure 2; in the solid state in the form of hot briquetted iron (HBI) on a thermal briquette press - figure 3 and in the form of directly reduced iron (DRI) on a shaft metallization furnace - Fig. 4.

Thus, the above-described variant application of the method for producing ferrous metal from brown-iron ore of an oolitic structure makes it possible to increase the competitiveness of such new mining and metallurgical projects as the Ayat project in Kazakhstan (developer - Tobol Corporation) and the Bakcharsky project in Russia (developer - Tomsk mining company; Corporation "Metals of Eastern Siberia").

Implementation of the proposed method for producing ferrous metal is possible within the framework of the Bakcharsky project, which is being developed for the industrial development of huge reserves of brown iron-ore ores of the oolitic structure in the bowels of the territory of the Tomsk Region. One of the options for pre-project considerations involves: developing a subsurface site according to the “Method for the extraction of solid minerals from a deeply irrigated water deposit” (patent RU 2459082); enrichment of mined ore to produce OMK is carried out according to the “Method for processing mineral raw materials ...” (patent RU 2402499); if necessary, clean OMK from harmful impurities according to the “Method for producing a phosphorus-free oolitic iron ore concentrate” (patent RU 2449031) and obtain pelletized OMK according to the “Method for producing pelletized metallurgical raw materials” (patent RU 2458158), and production of ferrous metal according to the proposed method.

This option of pre-design considerations involves the implementation of an integrated production scheme "mine - concentration plant - mini-metallurgical plant."

Some technical and economic assessments of the NATN of the metallurgical part of the Bakcharsky project, implemented according to the implemented scheme, show that the commodity steel product produced at the Bakcharsky mining and smelting plant covers the annual demand for it throughout the Siberian region. When 11.2 million tons / year of ore are mined in one section of the mine after its concentration and pelletizing, the following will be produced: 2.6 million tons / year of pellets and HBI, ~ 100 thousand tons / year DRI metallized; steel was produced in an electric arc furnace, thin slabs were poured, strips were hot rolled and 1.5 million tons / year of hot-rolled coils were obtained.

In addition, pelletized and metallized products (pellets, HBI, DRI) are independent commercial products that are economically feasible for use at various metallurgical enterprises according to different logistic schemes within a radius of ~ 500 km from the place of their production.

The general technical and economic effect of the invention is to overcome the disadvantages of the agglomeration scheme for using OMK by increasing the efficiency of the pyrometallurgical redistribution of OMK in the magnetically active state according to the introduced scheme by supplying OMK (HBI) to the magnetically active zones of the pyrometallurgical plants.

Claims (10)

1. A method for producing ferrous metal by redistributing an oolitic brown iron ore ore purified from vein minerals and harmful impurities of a firing magnetic concentrate (OMK) in a pyrometallurgical installation, characterized in that OMK is fed into the magnetically active zone of the pyrometallurgical installation heated to 650-860 ° C. 2. The method according to claim 1, characterized in that ferrous metal is obtained in liquid form by supplying OMK to the arc burning zone of an electric arc steelmaking furnace. 3. The method according to claim 1, characterized in that the ferrous metal is obtained doughy in the form of cricket iron or crits by feeding OMK into an induction crucible furnace. 4. The method according to claim 1, characterized in that the ferrous metal is obtained in solid form in the form of hot briquetted iron (HBI) by feeding into a magnetic briquette press. 5. The method according to claim 2, characterized in that critical iron, heated to 1250-1350 ° C, is additionally fed into the working space of said furnace. 6. The method according to claim 2, characterized in that hot briquetted iron, heated to 650-860 ° C, is additionally fed into the working space of said furnace. 7. The method according to claim 2, characterized in that OMK heated to 750-860 ° C, hot-briquetted iron heated to 750-860 ° C and critical iron heated to 1250-1350 ° C are fed into the working space of the said furnace. . 8. The method according to claim 3, characterized in that in the working space of the induction crucible furnace additionally serves hot briquetted iron, heated to 750-860 ° C. 9. The method according to claim 3, characterized in that the ferrous metal is obtained in solid form by treating the critical iron by forging or pressing in a reducing medium at a temperature of 1250-1350 ° C, supported by induction heating. 10. The method according to claim 1, characterized in that the ferrous metal is obtained in liquid form by feeding to the magnetically active zone of the reduction shaft furnace, hot briquette iron (HBI) obtained from OMK, heated to temperatures close to the Curie point for iron, and, if necessary , pellets.

Images