CN113684337A - Method and device for optimizing iron ore by gas coal double-base direct reduction and magnetic separation - Google Patents
Method and device for optimizing iron ore by gas coal double-base direct reduction and magnetic separation Download PDFInfo
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 165
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- 229910052742 iron Inorganic materials 0.000 title claims abstract description 71
- 238000007885 magnetic separation Methods 0.000 title claims abstract description 55
- 238000000034 method Methods 0.000 title claims abstract description 44
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Classifications
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/14—Multi-stage processes processes carried out in different vessels or furnaces
- C21B13/146—Multi-step reduction without melting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C21/00—Disintegrating plant with or without drying of the material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C23/00—Auxiliary methods or auxiliary devices or accessories specially adapted for crushing or disintegrating not provided for in preceding groups or not specially adapted to apparatus covered by a single preceding group
- B02C23/08—Separating or sorting of material, associated with crushing or disintegrating
- B02C23/14—Separating or sorting of material, associated with crushing or disintegrating with more than one separator
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C1/00—Magnetic separation
- B03C1/02—Magnetic separation acting directly on the substance being separated
- B03C1/30—Combinations with other devices, not otherwise provided for
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
- B03C3/017—Combinations of electrostatic separation with other processes, not otherwise provided for
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/0046—Making spongy iron or liquid steel, by direct processes making metallised agglomerates or iron oxide
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/0073—Selection or treatment of the reducing gases
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/02—Roasting processes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
Abstract
The invention relates to the technical field of energy-saving comprehensive utilization of mineral resources, in particular to a method and a device for optimizing iron ore by gas coal double-base direct reduction magnetic separation; the method specifically comprises the steps of treating raw materials, and carrying out reduction roasting on a mixture of the materials and the reduced coal by using a gas-coal double-base direct reduction roasting kiln; cooling the iron ore particle materials subjected to reduction roasting, and sequentially carrying out coal separation and recycling system, double-roller grinding system, Raymond grinding system and magnetic separation optimization system to obtain optimized iron concentrate powder, wherein the grade Fe of the optimized iron concentrate powder is more than 78%; the invention solves the problems of low reduction efficiency, long reduction heating time, high heating temperature and poor heat preservation effect in the prior art.
Description
Technical Field
The invention belongs to the technical field of energy-saving comprehensive utilization and direct reduction of mineral resources, and relates to a gas-coal double-base direct reduction roasting kiln and a mineral optimization method; in particular to a method and a device for optimizing iron ore by gas coal double-base direct reduction and magnetic separation.
Background
The direct reduced iron is an optimal and indispensable residual element diluent for smelting high-quality steel; the prior direct reduction process generally requires that the iron-containing Fe of a reduced iron raw material is more than 68.5 percent, the natural raw material is in scarcity, and the natural raw material is difficult to meet the requirement of producing the direct reduced iron raw material in a large scale; secondly, although the energy consumption of the existing gas-based shaft furnace reduction process is 355 kg/ton < 392 kg/ton of the energy consumption of blast furnace ironmaking, the process has the disadvantages of furnace caking, smooth blanking, difficult control of thermal engineering and unstable operation, and becomes the fatal weakness of the existing gas-based shaft furnace reduction process, so that the industrial production and application of the gas-based shaft furnace process are frequently frustrated. In the separation process after the roasting process, incomplete separation and screening treatment often occurs, so that the iron content of the final product is not high.
Disclosure of Invention
The invention overcomes the defects of the prior art and provides a method and a device for optimizing iron ore by gas-coal double-base direct reduction magnetic separation.
In order to achieve the above object, the present invention is achieved by the following technical solutions.
A method for optimizing iron ore by gas coal double-base direct reduction magnetic separation comprises the following steps:
s1: raw material treatment: respectively sieving, granulating, drying and screening iron oxide ore and reducing agent coal to obtain iron ore granular materials with the grain size of 3-40mm, mixing coal particles with the grain size of 5-10mm and coal particles with the grain size of 1-5mm with the iron ore granular materials according to the mass percent of 8% and 6% to obtain mixed materials, wherein the weight percent of water in the mixed materials is less than 10%.
S2: gas-coal double-base direct reduction roasting: carrying out reduction roasting on the mixed material by using a gas-coal double-base direct reduction roasting kiln; the roasting kiln includes the kiln body, the internal snakelike flue that is provided with circuitous from top to bottom of kiln, snakelike flue from the top down divide into the three-layer, does in proper order: a roasting preheating section, a roasting heating section and a roasting reduction section; the roasting heating temperature in the roasting heating section is 900-960 ℃; the roasting reduction temperature in the roasting reduction section is 960-1030 ℃; the roasting preheating section is connected with a flue gas collecting and air inducing device, a preheating material pool is arranged above the roasting preheating section, the preheating material pool is communicated with the roasting preheating section through a preheating material pipe, the bottom of the roasting preheating section is communicated with a vertical blanking channel, and the blanking channel penetrates through and is isolated from the roasting heating section and the roasting reduction section; a heat preservation reduction connecting section is supported below the roasting reduction section; the bottom end of the blanking channel is communicated with an air cooling pipe for cooling materials, a reducing gas preheating and reducing device is arranged in the air cooling pipe, and the reducing gas preheating and reducing device is connected with a reducing gas pipeline; and an air supply preheater and a cooling hot air collector are arranged on the outer wall of the upper end of the air cooling pipe.
When the smoke temperature of the roasting reduction section reaches 900-950 ℃, the iron ore particle materials are fed along the preheating material pool, the preheating material pipe and the blanking channel at the blanking speed v 1; meanwhile, reducing gas is introduced into the blanking channel, and when the flue gas temperature of the roasting reduction section reaches 980 ℃, the blanking speed is v 2; v2 is 5-6 times of v 1; iron ore particle materials are paved and stacked in a preheating material pool to the thickness of 200-300 mm; the rising speed of the flue gas temperature in the roasting reduction section is less than or equal to 2 ℃/min.
S3: the iron ore particle materials subjected to gas coal double-base direct reduction roasting enter an air cooling pipe; after the reduction roasting, the obtained product falls into an air cooling pipe to be cooled to 45-55 ℃.
S4: the cooled materials sequentially pass through a coal separation and recycling system to respectively obtain reduced materials and recycled coal particles with the particle size of 1-5 mm.
S5: sequentially passing the reduced materials through a double-roller mill, a magnetic separator, a screening and extracting device, a Raymond mill, a lifter for circular grinding, an ash-pumping and dust-removing device and a medium-magnetism selection device to obtain optimized reduced iron fine powder with the particle size of more than 300 meshes; the weight percentage of Fe contained in the optimized reduced iron fine powder is more than 78%.
Preferably, the cooled roasted material is fed under the control of a material guide impeller, and the rotating speed of the material guide impeller is 4-6 revolutions per hour.
Preferably, the reducing gas is H2 or CO.
Preferably, the reducing gas passes through a reducing gas preheating reduction device (9) and is directly contacted with the roasted material to fully absorb the cooling heat energy of the roasted material, and the temperature of the reducing gas is more than 850 ℃.
Preferably, the particle size of the reducing agent coal is less than 10mm, the sulfur-containing S is less than 0.6%, and the volatile matter is more than 8%.
Preferably, the preheating air supply temperature of the air supply preheater is 320-380 ℃.
Preferably, the temperature of the flue gas discharged from the roasting preheating section is 160-200 ℃.
The utility model provides a device of gas coal double-base direct reduction magnetic separation optimization iron ore, includes raw materials processing system, reduction roasting kiln, coal separation system of recycling, circulation grinding system and magnetic separation optimization system, flue gas waste heat utilization system.
The raw material processing system comprises an iron ore screening granulator and an iron ore screening machine which are connected, and a coal screening granulator and a coal screening machine which are connected, wherein the iron ore screening machine and the coal screening machine are respectively connected to the mixed material output device.
The reduction roasting kiln comprises a kiln body, a roundabout snake-shaped flue is arranged in the kiln body from top to bottom, the snake-shaped flue is divided into three layers from top to bottom, and the three layers are sequentially: a roasting preheating section, a roasting heating section and a roasting reduction section; the roasting preheating section is connected with a smoke induced air collecting device, a preheating material pool is arranged above the roasting preheating section, the preheating material pool is communicated with the roasting preheating section through a preheating material pipe, the bottom of the roasting preheating section is communicated with a vertical blanking channel, and the blanking channel penetrates through and is isolated from the roasting heating section and the roasting reduction section; the roasting reduction section is connected with a burner of a combustion chamber; the roasting heating temperature in the roasting reduction section is 960-1030 ℃; the bottom end of the blanking channel is communicated with an air cooling pipe for cooling materials, and the middle upper part of the air cooling pipe is provided with a reducing gas preheating and reducing device; the inlet of the reducing gas preheating and reducing device is communicated with a reducing gas pipeline; the pressure of the reducing gas in the reducing gas pipeline is higher than the marked pressure of 600-1200 Pa; the bottom of the air cooling pipe is connected with an output lifting device.
The coal separation and recycling system comprises a magnetic separation device and a coal separation and recycling device which are connected, and the output lifting device is connected with the magnetic separation device.
The circulating grinding system comprises a pair roller mill, a magnetic separator, a screening and extracting device, a Raymond mill, a centrifugal extracting device and a lifter which are connected in sequence; the magnetic separation optimization system comprises a medium magnetic concentration device.
The magnetic separation device is connected with the opposite roller mill, and the centrifugal extraction device is connected with the medium magnetic concentration device; the separated coal recycling device is connected with the mixed material output device.
Further, the iron ore screening granulator is connected with an iron ore screening machine through a flue gas purification and drying device; the coal screening granulator is connected with the coal screening machine through a flue gas purification and drying device; the smoke induced air collecting device is connected with the smoke purifying and drying device.
The device further comprises an ash and dust removing system, wherein the ash and dust removing system comprises an ash and dust removing device and an electrostatic dust removing device which are sequentially connected; the pair roller mill, the centrifugal pumping device, the middle magnetic concentration device and the separated coal recycling device are respectively connected with the ash and dust removing device.
Compared with the prior art, the invention has the following beneficial effects:
the method comprises the steps of screening, granulating and drying iron ore and reducing agent coal respectively, introducing heating flue gas into a flue gas purification and heating drying device, enabling the flue gas to flow through gaps of raw material particles, enabling tiny dust and harmful substances in the flue gas to be bonded and adsorbed by the raw material particles, incidentally pumping ash to remove the tiny dust and the harmful substances in a screening process, enabling the raw material particles to become flue gas purification fillers, enabling the flue gas to be purified and environment-friendly, enabling the temperature of the purified flue gas to be lower than 60 ℃, reducing environment-friendly investment, drying the raw material, obviously improving utilization efficiency of waste heat of the flue gas, and screening to obtain particle materials.
② in the iron ore screening process, part of impurities (6-10%) in the iron ore are directly removed by ash extraction, the energy consumption of roasting and heating is reduced by more than 6%, and the production process is environment-friendly.
And the reduction contact area of the gaps of the mixed material particles is increased, the capacity and the retention space of the reducing gas are sufficient, and the reaction time is sufficient.
The gaps of the mixed material particles are convenient for the roasting material to absorb the heat energy of the flue gas and evaporate water quickly and discharge the water along with the flue gas in time, and the consumption of roasting and heating natural gas is obviously reduced.
The gaps of the mixed material particles are favorable for reduction reaction, the reduced gas naturally ascends and escapes in time, and the concentration of the reduced gas is increased in time.
Sixthly, the gaps of the mixed material particles are beneficial to the gas after reduction and the excess reducing gas to overflow into the serpentine flue at the heating section and the reduction section, so that the excess reducing gas and the excess air can be timely and fully combusted in the serpentine flue, and the utilization efficiency of the circulating heat energy is improved; and the full convective reduction reaction of the double gas coal bases naturally formed in the blanking channel is facilitated.
2) For the gas coal double-base direct reduction roasting process: the gas coal double-base direct reduction roasting has the advantages that roasting heating smoke and blanking reduction are performed in the same way, roasting heating and combustion are sufficient in peroxide, the concentration of blanking reduction gas is sufficient and excessive, and the phenomenon that the concentration of the reduction gas is insufficient due to dilution of the reduction gas by smoke is avoided.
Blanking particle gaps: the contact surface of reducing gas is enlarged, the holding space is sufficient, the reaction time is sufficient, and the frequency conversion of the reducing time is adjustable.
The heat energy of the cooling of the roasting material is used for preheating and air supplying, the temperature of the preheated and air supplying is more than 330 ℃, the heat energy loss in the roasting process is obviously reduced, the cooling efficiency of the roasting material is improved, and the heat energy recycling efficiency is obviously improved.
The gas coal double-base direct reduction roasting is carried out, the reduction temperature is controlled at 930 +/-30 ℃, and the temperature can be controlled to be fine, fine and fine.
The gas-coal double-base direct reduction roasting kiln has the exhaust gas temperature of 160-200 ℃, the raw materials are heated and dried by using the waste heat of the exhaust gas, the exhaust gas temperature after heating and drying is less than 60 ℃, and the loss of the exhaust heat energy is obviously reduced.
The gas-coal double-base direct reduction roasting kiln has good heat preservation effect, the external temperature of the kiln is close to normal temperature, and the heat dissipation loss is greatly reduced.
The gas-coal double-base direct reduction roasting kiln heats flue gas up along the serpentine flue layer by layer in a natural heating way, so that the power consumption of flue gas induced air is very low.
The gas-coal double-base direct reduction roasting kiln has the advantages that the roasting material is directly under the gravity, and the power consumption of the blanking controlled by the impeller is very low.
The gas-coal double-base direct reduction roasting is characterized in that in the roasting reduction process, the roasted mixed material slowly descends along with the rotating speed of the material guide, the reducing gas slowly ascends along with the preheating, heating and reduction of gaps of grains of the roasted material, a gas-base and coal-base convection reduction reaction is naturally formed in the blanking channel, and the reduced gas and the excessive reducing gas overflow into the snake-shaped flue from the overflow port.
The coal-based convection reduction: in the roasting process, coal-based reducing agent coal naturally and slowly descends along with roasted material particles under the control of a material guide impeller, reducing gas is reduced and heated along with a blanking gap and slowly ascends to form a coal-based convection reduction reaction.
Gas-based convection reduction: in the roasting process, gas-based reducing gas enters the cooling pipe from the middle upper part of the cooling pipe, and the reducing gas naturally and slowly ascends along with the preheating reduction of roasting particle gaps to form a gas-based convection reduction reaction.
Overflowing the excessive reducing gas into a snake-shaped flue: the excess reducing gas and the excess air in the serpentine flue are timely and fully combusted, the investment and the cost of flue gas treatment equipment are saved, the energy-saving and recycling efficiency of flue gas in the roasting process is obviously improved, the energy consumption of roasting and heating is obviously reduced, the emission is reduced, and the environment is protected.
The air supply is preheated by utilizing the cooling heat energy of the roasting material, the self heat absorption energy consumption of the air supply is reduced, the cooling heat energy of the roasting material is recycled, and the consumption of heating natural gas is obviously reduced.
The snakelike flue gas holds the big heat-retaining energy storage of space, both sides wall heating is even, instantaneous heating temperature is too high, can in time fully alleviate.
And (3) roasting and heating: the roasting heating flue gas slowly goes upwards from the lower layer-by-layer snake-shaped natural heating along the reduction section snake-shaped flue, the heating section snake-shaped flue and the preheating section snake-shaped flue, and the heat exchange efficiency is obviously improved.
The roasting material falls into the blanking channel of the preheating section, the roasting material is in direct contact with the heating flue gas, the roasting material fully absorbs the heat energy of the flue gas, and the moisture is quickly evaporated and discharged along with the flue gas in time.
The roasting material falls into the heating section blanking channel, the reduced gas and the excess reducing gas overflow into the serpentine flue from the heating section overflow port, the concentration of the reducing gas is increased in time, the excess reducing gas and the excess air in the serpentine flue are timely and fully combusted, the environment is friendly, the environment-friendly investment is reduced, and the heat energy is timely and circularly utilized, so that the efficiency is obviously improved.
The roasting material falls into a blanking channel of the reduction section, the reduced gas and the excess reducing gas overflow into the serpentine flue from an overflow port of the reduction section, the excess reducing gas and the excess air in the serpentine flue are sufficiently combusted in time, the excess air is timely and adjustable by utilizing the preheated hot air, the pollution emission is reduced, and the environment is protected.
The roasted material falls into a material channel of the heat-preservation reduction connecting section, the reduction temperature is kept well, the concentration of the reduction gas is sufficient, the reduction time is sufficient, and the convection reduction is more sufficient.
The roasting material falls into an air cooling pipeline, the roasting material is cooled and slowly descends under the control of the rotating speed of a material guide impeller of 4-6 revolutions per hour, and the power consumption of the rotating power of the material guide impeller is extremely low; the roasting material is naturally air-cooled to about 50 ℃ in the air-cooled pipe, so that the secondary oxidation of the roasting material is avoided, no water is used for magnetic separation optimization, the water resource consumption is saved, and the regional adaptability is strong.
The gas coal dual-base direct reduction roasting is characterized in that a partition plate is arranged between a roasting reduction section and a roasting heating section in a flue, and a flange is arranged at the tail end of the partition plate towards the roasting reduction section; the partition plate is arranged between the roasting heating section and the roasting preheating section, and flanges are symmetrically arranged in the roasting heating section at the tail end of the partition plate and the roasting preheating section, so that the temperature of each section is effectively guaranteed.
The gas-coal dual-base direct reduction roasting has the advantages that the reduction temperature, the reduction gas concentration and the reduction time are respectively controlled in the reduction roasting process, the mutual influence among various control parameters is relatively weak, the high-degree natural coordination control can be realized, the iron ore is carried out in the full convection reduction atmosphere, and the thermal engineering control is accurate and easy to control.
The gas-coal double-base direct reduction roasting process has internal and external preheating and heating, and heat energy recycling, the consumption of roasting and heating natural gas is obviously reduced, and the problems of low reduction efficiency, long reduction and heating time, high heating temperature and poor heat preservation effect in the prior art are solved; because the reduction temperature is controlled at 930 +/-30 ℃ for low-temperature reduction, the roasted material is extremely easy to be ground, and convenience is provided for further magnetic separation optimization.
3) And (3) separating and recycling coal: the roasted material is subjected to a coal separation and recycling system to obtain a reduced material, and recycled coal particles with the particle size of 1-5mm are obtained, so that the separated coal particles are recycled, the roasting and heating energy consumption is obviously reduced, and the recycling energy-saving utilization efficiency is obviously improved.
4) And (3) circulating grinding: after the iron ore is directly reduced and roasted at low temperature by the gas-coal double-base, the roasted material is extremely easy to be ground, impurities and reduced iron are extremely easy to be separated, and impurity dust is timely removed by magnetic separation and ash extraction; the roasted reducing material is circularly ground, magnetically separated, ash extracted and dedusted by a double-roller mill, a magnetic separator, a screening and extracting device, a Raymond mill, a centrifugal extracting device and a hoister in sequence to obtain the reduced material with the particle size of more than 300 meshes.
5) Magnetic separation optimization: and (3) concentrating the separated material with the grain size of more than 300 meshes by using a medium-magnetic concentration device to obtain an optimized fine iron powder product containing more than 78% of Fe, so that convenience is provided for further producing reduced iron.
6) Ash and dust removing system: the ash removal and dust removal system not only removes ash and dust but also provides system negative pressure for the magnetic separation optimization process, and the electrostatic dust removal further improves the dust removal efficiency.
7) Flue gas waste heat utilization: the smoke induced air collecting device introduces smoke into the smoke purifying and drying device, so that the smoke purifying and raw material drying are realized, the smoke waste heat is recycled, the emission is reduced, and the environment is protected.
The method is suitable for treating various types of iron oxide ores, the various types of iron oxide ores can be mixed and roasted, the magnetic separation optimization does not influence the recovery rate of iron, the optimized iron concentrate powder prepared by the method has the advantages that the grade Fe is more than 78 percent, the harmful impurity removal effect is obvious, the sulfur removal efficiency is more than 60 percent, the phosphorus removal efficiency is more than 68 percent, and the problem of scarcity of reduced iron raw materials is solved.
Compared with other existing processes at home and abroad, the process flow is short, flexible and practical, energy-saving and efficient, free of adhesion and caking, large in treatment capacity, stable in product quality, small in relative investment, quick in effect, capable of being developed while producing, finally forming intensive large-scale production, capable of realizing rolling explosive growth development and the like; therefore, the process is a high-quality, low-consumption, energy-saving and efficient clean, energy-saving, direct reduction, green development and innovation process, has wide market development prospect, is easy to popularize, has huge energy-saving development potential due to the fact that the comprehensive energy consumption is less than one half of that of other processes, particularly improves the quality structure and energy structure of steel products, breaks away from the constraint of coking coal resources on the production and development of steel, and has more advantages from the source of energy conservation and emission reduction.
Drawings
FIG. 1 is a main sectional view of the structure of a gas coal double-base direct reduction roasting kiln of the present invention.
FIG. 2 is a schematic sectional view taken along the plane A-A in FIG. 1.
FIG. 3 is a schematic connection diagram of the device for optimizing iron ore by gas coal double-base direct reduction magnetic separation.
In the figure: the device comprises a kiln body 1, a preheating material pool 2, a preheating material pipe 3, a blanking channel 4, a roasting preheating section 5, a roasting heating section 6, a roasting reduction section 7, a heat preservation reduction connecting section 8, a reducing gas preheating reduction device 9, an air cooling pipe 10, a guide impeller 11, a guide platform 12, a storage bin 13, an output lifting device 14, a heat preservation sealing gap 15, an air supply preheater 16, a cooling hot air collector 17, a support beam 18, a backing ring 19, a support column 20, a distributing machine 21, a serpentine flue 22, a temperature monitoring device 23, a fire observation hole 24, a combustion chamber 25, a heating section reduced gas overflow port 26 and a reduction section reduced gas overflow port 27.
101, 102, 103, 104, 105 and 106 are iron ore screening granulators, coal screening granulators, flue gas purification and drying devices, iron ore screening machines and coal screening machines, respectively;
301 is a magnetic separation device, and 302 is a separated coal recycling device; 401 is a pair roller mill, 402 is a magnetic separator, 403 is a screening and extracting device, 404 is a Raymond mill, 405 is a centrifugal extracting device, 406 is a hoisting machine, 501 is a middle magnetic concentration device, 502 is optimized iron concentrate powder, 601 is an ash and dust removing device, 602 is an electrostatic dust removing device, and 701 is a smoke induced air collecting device.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail with reference to the embodiments and the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The technical solutions of the present invention are described in detail below with reference to the embodiments and the drawings, but the scope of protection is not limited thereto.
As shown in fig. 3, the device for optimizing iron ore by gas coal double-base direct reduction and magnetic separation mainly comprises 7 parts: the system comprises a raw material processing system, a gas-coal double-base direct reduction roasting kiln, a coal separation recycling system, a circulating grinding system, a magnetic separation optimizing system, an ash and dust removing system and a flue gas waste heat utilization system.
The raw material processing system comprises an iron ore screening granulator 101, a coal screening granulator 102, a flue gas purification and drying device 103, an iron ore screening machine 104, a coal screening machine 105 and a mixed material output device 106 which are connected in sequence. The iron ore screening granulator 101 is connected with an iron ore screening machine 104 through a flue gas purification and drying device 103; the coal screening granulator 102 is connected to a coal screening machine 105 via a flue gas cleaning and drying device 103. The iron ore screening machine 104 and the coal screening machine 105 are connected to a mixed material output device 106, respectively.
Gas-coal double-base direct reduction roasting kiln: as shown in fig. 1-2, wherein: kiln body 1 is hollow shell, and the internal brickwork of kiln 1 from top to bottom has circuitous snakelike flue 22, and the heating of the wide 24 centimetre both sides walls of snakelike flue is even, and snakelike flue from the top down divide into the three-layer, does in proper order: the device comprises a roasting preheating section 5, a roasting heating section 6 and a roasting reduction section 7, wherein a preheating material pool 2 is concavely arranged in the middle of the top wall of a kiln body 1 towards the inner side of the kiln body 1, a material distributing machine 21 is arranged above the preheating material pool 2, and a mixed material output device 106 is connected with the material distributing machine 21; the materials passing through the raw material processing system are sent to a preheating material pool 2 through a distributing machine 21; a plurality of preheating pipes 3 are uniformly arranged on the bottom surface of the preheating material pool 2, the preheating material pool 2 is communicated with a roasting preheating section 5 through the preheating pipes 3, the bottom of the roasting preheating section 5 is communicated with a vertical blanking channel 4, and the blanking channel 4 penetrates through and is isolated from the roasting heating section 6 and the roasting reduction section 7; the bottom end of the blanking channel 4 is communicated with an air cooling pipe 10 for cooling materials, and the middle upper part of the air cooling pipe is provided with a reducing gas preheating and reducing device 9; the reducing gas preheating and reducing device 9 is communicated with a reducing gas pipeline, and a reducing gas outlet of the reducing gas preheating and reducing device 9 is arranged at the upper end of the air cooling pipe 10 and faces the blanking channel 4. The reducing gas preheating and reducing device 9 is used for providing reducing gas for the blanking channel 4; the pressure of the reducing gas in the reducing gas pipeline is 600-1200 Pa; an air supply preheater 16 and a cooling hot air collector 17 are arranged on the outer wall of the upper end of the air cooling pipe 10; one end of the inlet of the air supply preheater 16 is connected with the cooling hot air collector 17, and the other end is connected with the burner of the combustion chamber 25. The side wall of the upper part of the blanking channel 4 at the roasting heating section 6 and the roasting reduction section 7 is respectively and uniformly provided with a heating section reduced gas overflow port 26 and a reduction section reduced gas overflow port 27. The roasting reduction section 7 is connected with a burner of a combustion chamber 25. The side wall of the roasting reduction section 7 is provided with a fire observation hole 24, and a temperature monitoring device 23 is arranged above the fire observation hole 24.
And a partition plate is arranged between the roasting reduction section 7 and the roasting heating section 6, and a flange is arranged at the tail end of the partition plate towards the roasting reduction section 7. And a partition plate is arranged between the roasting heating section 6 and the roasting preheating section 5, and flanges are symmetrically arranged in the roasting heating section 6 and the roasting preheating section 5 at the tail end of the partition plate. And communicated heat-preservation sealing gaps 15 are arranged between the side wall of the kiln body 1 and the preheating material pool 2 and between the side wall of the kiln body 1 and the roasting system. A heat-preservation reduction connecting section 8 is supported below the roasting reduction section 7, a supporting beam 18 is arranged between the lower part of the heat-preservation reduction connecting section 8 and the bottom surface of the kiln body 1, a backing ring 19 is arranged below the bottom surface of the kiln body 1, and a supporting column 20 is arranged between the backing ring 19 and the ground.
A material guiding impeller 11 is arranged below the tail end of the air cooling pipe 10, a material guiding platform 12 is arranged below the material guiding impeller 11, a storage bin 13 is arranged below the material guiding platform 12, and an output lifting device 14 is arranged below the storage bin 13.
The material sent out from the kiln body 1 is sent to a coal separation and recycling system by an output lifting device 14, and the coal separation and recycling system comprises a magnetic separation device 301 and a separated coal recycling device 302.
The circulating grinding system comprises a double-roller mill 401, a magnetic separator 402, a screening and extracting device 403, a Raymond mill 404, a centrifugal extracting device 405 and a hoister 406 which are connected in sequence; the magnetic separation optimization system comprises a middle magnetic selection device 501;
the magnetic separation device 301 is connected with the paired roller mill 401, and the centrifugal extraction device 405 is connected with the medium magnetic concentration device 501; the optimized fine iron powder 502 is refined by a medium magnetic refining device 501. The separated coal recycling device 302 is connected with the mixed material output device 106.
The ash and dust removing system comprises an ash and dust removing device 601 and an electrostatic dust removing device 602 which are connected in sequence; the double-roller mill 401, the centrifugal extraction device 405, the medium-magnetic concentration device 501 and the separated coal recycling device 302 are respectively connected with an ash and dust removing device 601.
The flue gas waste heat utilization system is a flue gas induced air collecting device 701, one end of the flue gas induced air collecting device 701 is connected with the snakelike flue, and the other end of the flue gas induced air collecting device 701 is connected with the flue gas purification and drying device 103.
And an iron ore screening granulator 101 for subjecting the iron oxide ore to screening granulation to prepare for drying. The coal screen granulator 102 is configured to dry the reduced coal by screening and granulating the reduced coal.
Flue gas purification drying device 103: the method comprises the following steps of directly reducing the flue gas waste heat of a roasting kiln by using a gas-coal double-base method, wherein the flue gas temperature is 160-200 ℃, and the cooling hot air of a roasting material is used as a standby heat source; the flue gas flows through gaps of the particles of the raw and auxiliary materials respectively, the flue gas is purified, the particles of the raw and auxiliary materials become flue gas purification fillers to be dried, the flue gas purification environment-friendly investment is reduced, the flue gas temperature after the flue gas purification is less than 60 ℃, the flue gas waste heat loss is reduced, and the utilization efficiency of the flue gas waste heat is obviously improved; the weight percentage of the water content of the raw and auxiliary material particles is less than 10 percent.
The iron ore screening machine 104: the method is characterized in that the dried iron ore is crushed and screened to obtain iron ore particles with the particle size of 3-40mm, impurity dust in the fine ore with the particle size of less than 3 mm is removed by dust extraction, the dried fine ore is returned to be granulated again, granulation production is facilitated, the production process is environment-friendly, and qualified raw materials are provided for roasting reduction.
Coal screening machine 105: and screening the dry and reduced coal to obtain coal particles with the particle size of 5-10mm, returning the pulverized coal with the particle size of less than 5mm to the wet coal screening granulator 102 for re-granulation, and facilitating granulation production.
The mixed material output device 106: and uniformly mixing the obtained iron ore particles of 3-40mm, the obtained coal particles of 5-10mm according to the proportion of 8% and the obtained coal particles of 1-5mm according to the proportion of 6% to obtain a mixed material, and inputting the mixed material into a feeding port of a distributing machine 21 of the gas-coal dual-base direct reduction roasting kiln.
2) Gas-coal double-base direct reduction roasting:
the method for gas coal double-base direct reduction roasting comprises the following steps:
filling a discharging channel 4 of a roasting kiln with iron ore particle mixed materials of 3-40mm by a distributing machine 21, and tiling and stacking the iron ore particle mixed materials in a preheating material pool 2 to achieve the thickness of 200-300 mm; starting a burner of a combustion chamber 25, heating flue gas, wherein the temperature rise speed of the flue gas is less than or equal to 2 ℃/min, monitoring the temperature of each section in the serpentine flue through a temperature monitoring device 23, when the temperature of the flue gas in a reduction section flue reaches 900 ℃, slowly opening a material guide impeller 11 to start feeding at 1 r/h, simultaneously slowly opening a main regulating valve of a gas-based reduction gas pipeline 9 to start gas supply, and adjusting the pressure of the reduction gas to a sufficient reduction range required by the roasted material along with the temperature rise, wherein the pressure is adjusted to be within the range: the air pressure of the reducing gas is higher than the marked air pressure of 600-1200 Pa; the feeding speed is adjusted to about 6 revolutions per hour when the temperature of the snakelike flue of the reduction section rises to 980 ℃ along with the rising speed of the reduction temperature of the roasted material.
The roasting material falls into a roasting preheating section 5: the reduction blanking channel and the snakelike flue are located in the same space in the preheating section, the roasting material fully absorbs heat energy of flue gas, moisture is quickly evaporated and discharged along with the flue gas, and the temperature of the flue gas is 160-200 ℃.
Thirdly, the roasting material falls into a roasting heating section 6: the heating section blanking channel 4 is separated from the snakelike flue 22, and a heating section reducing gas overflow port 26 is arranged at the upper part of the side wall of the heating section blanking channel; the roasting material slowly descends along with the rotating speed of the material guide, the reducing gas is heated and ascends along with the convective reduction of gaps of particles of the roasting material, the reduced gas overflows into the serpentine flue from the overflow port, the concentration of the reducing gas in the blanking channel is increased in time, the excess reducing gas and the excess air in the serpentine flue are fully combusted in time, excess reducing gas treatment equipment is omitted, the cost is saved, the environment is protected, the consumption of roasting natural gas is obviously reduced, the emission of flue gas is reduced, and the energy-saving recycling efficiency of the excess reducing gas is obviously improved.
Fourthly, the roasted material falls into a reduction section: the blanking channel 4 of the reduction section is separated from the snakelike flue 22, so that the reduction gas is prevented from being diluted by the flue gas, and the concentration of the reduction gas can be adjusted in time according to requirements; the two side walls of the serpentine flue with the width of 24 cm in the reduction section store heat, store energy and heat uniformly, and the over-high instantaneous temperature can be relieved in time; the heating smoke is naturally heated and ascends layer by layer along with the serpentine flue; the heating combustion is sufficient, the heating temperature is controlled to be 930 +/-30 ℃, the preheating and air supply are adjustable, the speed of the roasted material naturally falls along with the rotating speed of the material guide impeller, the speed is adjustable, and the convection reduction time is sufficient.
The roasting material falls into a heat preservation reduction connecting section: the reduction temperature is kept well, the reduction gas is sufficient, the roasted material passes through the reduction section and the heat preservation section for more than 6 hours at 6 revolutions per hour, the reduction time required by the roasted material is 3 hours, the reduction time is sufficient, and the roasting convection reduction atmosphere is sufficient.
Sixthly, the reducing gas enters the cooling pipe from the middle upper part of the cooling pipe 10, the reducing gas is slowly preheated along with the gaps of the particles, reduced and ascended, and gas-based convection reduction reaction is naturally formed in the blanking channel.
And the roasted material falls into the air cooling pipe 10, natural air cooling is performed to avoid reoxidation risk, an air supply preheater 16 and a cooling hot air collector 17 are arranged at the upper part of the outer side of the air cooling pipe, the roasted material cooling heat energy is utilized to further improve the temperature of hot air, and the preheating air supply temperature is generally 330-380 ℃, so that the heat absorption energy consumption of the hot air is obviously reduced, experiments show that the consumption of heating natural gas is relatively reduced by more than 18%, the roasted material is cooled to about 50 ℃, the cooling efficiency is improved, and the heat energy recycling efficiency in the roasting reduction process is obviously improved.
After being air-cooled, the baked materials pass through a material guide platform 12 and fall into a baking bin 13 under the control of a material guide impeller 11.
Ninthly, inputting the calcined material into a coal separation and reutilization system through an output lifting device 14;
the double-base direct reduction roasting of the coke gas not only forms a sufficient and efficient convection reduction reaction, but also ensures that the low-temperature reduction roasting material is extremely easy to mill and the impurities are extremely easy to separate, thereby providing convenience for further magnetic separation optimization.
3) Coal separation system of recycling: magnetically separating the roasted material by a magnetic separation device 301 to obtain a reduced material; and separating the coal. The separated coal is processed by a separated coal recycling device 302 to obtain recyclable coal particles with the particle size of 1-5mm, so that recycling and secondary separation are facilitated.
4) For the roller mill 401: and circularly grinding the roll mill to grind the reducing material to more than 200 meshes. A magnetic separator 402: the impurities are separated in time by the circular magnetic separation, and the processing energy consumption is reduced. Screening extraction device 403: the reducing material with more than 200 meshes is extracted in time by circular screening. Raymond mill 404: and grinding the reduced material with the granularity of more than 200 meshes to be more than 300 meshes by circularly grinding the reduced material by a Raymond mill. Centrifugal pumping device 405: the dust of the reduced material which is finely ground to more than 300 meshes is removed in time by a centrifugal pumping device 405, and the reduced material with more than 300 meshes is obtained. Elevator 406: the circular lifting of the lifter 405 is convenient for the circular grinding and magnetic separation ash extraction production.
5) Magnetic separation optimizing system: medium magnetic concentration device 501: and (3) concentrating the obtained reduced material with the granularity of more than 300 meshes by a medium magnetic concentration device 501 to obtain the optimized refined iron powder 502 with Fe being more than 78%. And (4) optimizing the iron fine powder 502 for inspection and warehousing, and improving the quality, high price and high-quality raw materials for related enterprises.
6) Ash and dust removing system: the ash and dust removing device 601 not only can extract ash and remove dust and remove impurities to reduce the abrasion of the induced draft fan, but also provides system negative pressure environment friendliness for the magnetic separation optimization process. Electrostatic precipitator 602: the electrostatic dust collection further improves the dust collection efficiency.
7) Flue gas waste heat utilization system: flue gas induced air collection device 701: and collecting flue gas generated by the gas coal double-base direct reduction roasting, and introducing the flue gas into a flue gas purification drying device 103 to heat and dry the raw materials.
Specifically, the method comprises the following steps:
example 1
Some iron oxide ores contain iron, Fe42.87% (by weight). The method comprises the following steps:
firstly, raw material treatment: screening, granulating, drying and screening an iron oxide ore Fe42.87% raw material and reducing agent coal respectively to obtain iron oxide ore particles with the particle size of 3-40mm and coal particles with the particle size of 5-10mm, mixing 8% coal particles with the particle size of 5-10mm and 6% coal particles with the particle size of 1-5mm according to a ratio with the iron oxide ore particles with the particle size of 3-40mm to obtain a mixed material, wherein the weight percentage of the mixed material is less than 10%.
② gas coal double-base direct reduction roasting: roasting the mixed material of iron oxide ore particles of 3-40mm in a gas-coal double-base direct reduction roasting test kiln, controlling the gas pressure of gas-base reduction gas to be 1000Pa higher than the labeled gas pressure, controlling the reduction temperature of a reduction section to be about 930 ℃, and controlling the rotating speed of a guide impeller to be about 6 r/h to obtain a roasting reduction material.
Thirdly, separating and recycling coal: magnetically separating the obtained roasting material reduction material by a magnetic separation device, and separating coal to obtain a reduction material; the separated coal is recycled through a separated coal recycling device to obtain recycled coal particles with the particle size of 1-5 mm.
Fourthly, circularly grinding and magnetic separation: and (3) circularly grinding, magnetically separating, ash pumping and dedusting the obtained reduced material by sequentially passing the reduced material through a double-roller mill, a magnetic separator, a screening and pumping device, a Raymond mill, a centrifugal pumping device and a lifter to obtain the reduced material with the granularity of more than 300 meshes.
Optimizing magnetic separation: and (3) concentrating the obtained reduced material with more than 300 meshes by a medium-magnetic concentration device to obtain optimized iron concentrate powder: fe80.35%, P0.012% and S0.016%; the content of other impurities meets the production requirement of the reduced iron.
Energy consumption per ton ore: the standard coal consumption of roasting and heating natural gas is 68.36 kg/ton ore, and the electricity consumption of magnetic separation is optimized to be 63 degrees/ton ore.
Example 2
An iron ore contains iron Fe48.63% (by weight). The method comprises the following steps:
firstly, raw material treatment: screening, granulating, drying and screening an iron oxide ore Fe48.63% raw material and reducing agent coal respectively to obtain iron ore particles with the particle size of 3-40mm and coal particles with the particle size of 5-10mm, mixing the coal particles with the particle size of 5-10mm according to the proportion of 8% and the particle size of 1-5mm with the iron oxide ore particles with the particle size of 3-40mm according to the proportion of 6% to obtain a mixed material, wherein the weight percentage of the mixed material is less than 10%.
② gas coal double-base direct reduction roasting: roasting the iron oxide ore particle mixture of 3-40mm in a gas-coal double-base direct reduction roasting test kiln, controlling the gas pressure of gas-base reduction gas to be 600-1200Pa higher than the labeled gas pressure, controlling the reduction temperature of a reduction section to be about 930 ℃, and controlling the rotating speed of a guide impeller to be about 6 r/h to obtain a roasting reduction material.
Thirdly, separating and recycling coal: magnetically separating the obtained roasting material reduction material by a magnetic separation device, and separating coal to obtain a reduction material; the separated coal is recycled through a separated coal recycling device to obtain recycled coal particles with the particle size of 1-5 mm.
Fourthly, circularly grinding and magnetic separation: and (3) circularly grinding, magnetically separating, ash pumping and dedusting the obtained reduced material by sequentially passing the reduced material through a double-roller mill, a magnetic separator, a screening and pumping device, a Raymond mill, a centrifugal pumping device and a lifter to obtain the reduced material with the granularity of more than 300 meshes.
Optimizing magnetic separation: and (3) concentrating the obtained reduced material with more than 300 meshes by a medium-magnetic concentration device to obtain optimized reduced iron fine powder: fe80.35%, P0.012% and S0.016%; the content of other impurities meets the production requirement of the reduced iron.
Energy consumption per ton ore: the standard coal consumption of roasting and heating natural gas is 67.31 kg/ton ore, and the electricity consumption of magnetic separation is optimized to be 61 degrees/ton ore.
While the invention has been described in further detail with reference to specific preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A method for optimizing iron ore by gas coal double-base direct reduction and magnetic separation is characterized by comprising the following steps:
s1: raw material treatment: respectively sieving, granulating, drying and screening iron oxide ore and reducing agent coal to obtain iron ore granular materials with the grain size of 3-40mm, mixing coal grains with the grain size of 5-10mm and coal grains with the grain size of 1-5mm with the iron ore granular materials according to the mass percent of 8% and 6% to obtain mixed materials, wherein the weight percent of water in the mixed materials is less than 10%;
s2: gas-coal double-base direct reduction roasting: carrying out reduction roasting on the mixed material by using a gas-coal double-base direct reduction roasting kiln; the roasting kiln includes the kiln body (1), be provided with circuitous snakelike flue from top to bottom in the kiln body (1), snakelike flue from the top down divide into the three-layer, does in proper order: a roasting preheating section (5), a roasting heating section (6) and a roasting reduction section (7); the roasting heating temperature in the roasting heating section (6) is 900-; the roasting reduction temperature in the roasting reduction section (7) is 960-1030 ℃; the roasting preheating section (5) is connected with a flue gas collecting and air inducing device, a preheating material pool (2) is arranged above the roasting preheating section (5), the preheating material pool (2) is communicated with the roasting preheating section (5) through a preheating material pipe (3), the bottom of the roasting preheating section (5) is communicated with a vertical blanking channel (4), and the blanking channel (4) penetrates through the roasting heating section (6) and the roasting reduction section (7) and is isolated from the roasting heating section (6) and the roasting reduction section (7); a heat-preservation reduction connecting section (8) is supported below the roasting reduction section (7); the bottom end of the blanking channel (4) is communicated with an air cooling pipe (10) for cooling materials, a reducing gas preheating and reducing device (9) is arranged in the air cooling pipe (10), and the reducing gas preheating and reducing device (9) is connected with a reducing gas pipeline; an air supply preheater (16) and a cooling hot air collector (17) are arranged on the outer wall of the upper end of the air cooling pipe (10);
when the smoke temperature of the roasting reduction section (7) reaches 900-; meanwhile, reducing gas is introduced into the blanking channel (4), and when the flue gas temperature of the roasting reduction section (7) reaches 980 ℃, the blanking speed is v 2; v2 is 5-6 times of v 1; iron ore particle materials are paved and stacked in a preheating material pool to the thickness of 200-300 mm; the rising speed of the flue gas temperature in the roasting reduction section (7) is less than or equal to 2 ℃/min;
s3: iron ore particle materials subjected to gas-coal double-base direct reduction roasting enter an air cooling pipe (10); after the reduction roasting is obtained, the mixture falls into an air cooling pipe (10) to be cooled to 45-55 ℃;
s4: the cooled materials sequentially pass through a coal separation and recycling system to respectively obtain reduced materials and recycled coal particles with the particle size of 1-5 mm;
s5: sequentially passing the reduced materials through a double-roller mill, a magnetic separator, a screening and extracting device, a Raymond mill, a lifter for circular grinding, an ash-pumping and dust-removing device and a medium-magnetism selection device to obtain optimized reduced iron fine powder with the particle size of more than 300 meshes; the weight percentage of Fe contained in the optimized reduced iron fine powder is more than 78%.
2. The method for optimizing iron ore by gas coal double-base direct reduction magnetic separation as claimed in claim 1, wherein the cooled roasted material is fed by a guide impeller rotating at 4-6 r/h.
3. The method for optimizing iron ore by using gas-coal double-base direct reduction magnetic separation as claimed in claim 1, wherein the reducing gas is H2Or CO.
4. The method for optimizing the iron ore by the double-base direct reduction magnetic separation of the gas coal according to the claim 1, characterized in that the reducing gas passes through a reducing gas preheating reduction device (9) and is directly contacted with the roasted material, the cooling heat energy of the roasted material is fully absorbed, and the temperature of the reducing gas is more than 850 ℃.
5. The method for optimizing iron ore by using double-base direct reduction magnetic separation of gas coal according to claim 1, wherein the particle size of the reducing agent coal is less than 10mm, the sulfur content is less than 0.6%, and the volatile matter is more than 8%.
6. The method for optimizing the iron ore by the double-base direct reduction and magnetic separation of the gas coal according to claim 1, characterized in that an air supply preheater (16) preheats the air supply temperature of 320-380 ℃.
7. The method for optimizing the iron ore by the double-base direct reduction and magnetic separation of the gas coal as claimed in claim 1, wherein the temperature of the flue gas discharged from the roasting preheating section (5) is 160-200 ℃.
8. A device for optimizing iron ore by gas-coal double-base direct reduction and magnetic separation is characterized by comprising a raw material processing system, a reduction roasting kiln, a coal separation and recycling system, a circulating grinding system, a magnetic separation optimizing system and a flue gas waste heat utilization system;
the raw material processing system comprises an iron ore screening granulator (101) and an iron ore screening machine (104) which are connected, and a coal screening granulator (102) and a coal screening machine (105) which are connected, wherein the iron ore screening machine (104) and the coal screening machine (105) are respectively connected to a mixed material output device (106);
the reduction roasting kiln comprises a kiln body (1), a roundabout snake-shaped flue is arranged in the kiln body (1) from top to bottom, the snake-shaped flue is divided into three layers from top to bottom, and the three layers are sequentially arranged: a roasting preheating section (5), a roasting heating section (6) and a roasting reduction section (7); the roasting preheating section (5) is connected with a smoke induced air collecting device (701), a preheating material pool (2) is arranged above the roasting preheating section (5), the preheating material pool (2) is communicated with the roasting preheating section (5) through a preheating material pipe (3), the bottom of the roasting preheating section (5) is communicated with a vertical blanking channel (4), and the blanking channel (4) penetrates through the roasting heating section (6) and the roasting reduction section (7) and is isolated from the roasting heating section (6) and the roasting reduction section (7); the roasting reduction section (7) is connected with a burner of a combustion chamber (25); the roasting heating temperature in the roasting reduction section (7) is 960-1030 ℃; the bottom end of the blanking channel (4) is communicated with an air cooling pipe (10) for cooling materials, and the middle upper part of the air cooling pipe (10) is provided with a reducing gas preheating and reducing device for self-tapping; the self-tapping hole of the reducing gas preheating and reducing device is communicated with a reducing gas pipeline; the pressure of the reducing gas in the reducing gas pipeline is higher than the marked pressure of 600-1200 Pa; the bottom of the air cooling pipe (10) is connected with an output lifting device (14);
the coal separation and recycling system comprises a magnetic separation device (301) and a separated coal recycling device (302) which are connected, and the output lifting device (14) is connected with the magnetic separation device (301);
the circulating grinding system comprises a pair roller mill (401), a magnetic separator (402), a screening and extracting device (403), a Raymond mill (404), a centrifugal extracting device (405) and a hoisting machine (406) which are connected in sequence; the magnetic separation optimization system comprises a middle magnetic selection device (501);
the magnetic separation device (301) is connected with the paired roller mill (401), and the centrifugal extraction device (405) is connected with the medium magnetic concentration device (501); the separated coal recycling device (302) is connected with the mixed material output device (106).
9. The device for optimizing iron ore by gas-coal double-base direct reduction magnetic separation according to claim 8, characterized in that the iron ore screening granulator (101) is connected with an iron ore screening machine (104) through a flue gas purification and drying device (103); the coal screening granulator (102) is connected with a coal screening machine (105) through a flue gas purification and drying device (103); the smoke induced air collecting device (701) is connected with the smoke purifying and drying device (103).
10. The device for optimizing iron ore by gas-coal double-base direct reduction and magnetic separation as claimed in claim 8, characterized by further comprising an ash and dust removing system, wherein the ash and dust removing system comprises an ash and dust removing device (601) and an electrostatic dust removing device (602) which are connected in sequence; the pair roller mill (401), the centrifugal extraction device (405), the middle magnetic concentration device (501) and the separated coal recycling device (302) are respectively connected with the ash and dust removing device (601).
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