CN113976310A

CN113976310A - Method and device for optimizing iron ore by magnetic separation of coal-based coking reduction roasting coke

Info

Publication number: CN113976310A
Application number: CN202111273215.7A
Authority: CN
Inventors: 张雷; 张凯玮; 张妍琪; 张辉; 张晋军; 张嘉妮; 梁军山; 梁志朴; 王永锋; 路宽; 陈小明
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-10-29
Filing date: 2021-10-29
Publication date: 2022-01-28

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 magnetic separation optimization of iron ore by reducing roasted coke through coal-based coking; the device comprises a raw material treatment flue gas waste heat utilization system, a coal-based coking reduction roasting system, a coke separation system, a circulating grinding system, a magnetic separation optimization system and an ash removal and dust removal system; the optimized refined iron powder product is finally obtained through the steps of raw material treatment, coal-based coking reduction roasting, iron ore reduction catalysis coking coal coking, coke separation, circular grinding and magnetic separation optimization; the invention is suitable for treating various types of iron oxide ores with TFe of more than 38 percent, the volatile matter of coking reduction roasting coke is less than 1.2 percent, the iron recovery rate is obviously improved, the grade of the optimized iron concentrate can reach more than TFe76 percent, the sulfur and phosphorus removal efficiency is more than 60 percent, the energy is saved by more than 50 percent, and the problems of high reduction efficiency, difficult control of thermal engineering, unstable product quality and rare defects of reduced iron raw materials in the prior art are solved.

Description

Method and device for optimizing iron ore by magnetic separation of coal-based coking reduction roasting coke

Technical Field

The invention belongs to the technical field of energy-saving comprehensive utilization and direct reduction of mineral resources, and relates to a coal-based direct reduction roasting kiln and a mineral optimization method; in particular to a method and a device for optimizing iron ore by magnetic separation of coal-based coking reduction roasting coke.

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. The traditional coking process has the problems of low heat energy recycling efficiency, high energy consumption, serious pollution and the like in the coking process.

Disclosure of Invention

The invention overcomes the defects of the prior art and provides a method and a device for magnetic separation optimization of iron ore by reducing roasted coke through coal-based coking.

In order to achieve the above object, the present invention is achieved by the following technical solutions.

A method for optimizing iron ore by magnetic separation of coal-based coking reduction roasting coke comprises the following steps:

s1: flue gas waste heat utilization in raw material treatment: treating iron ore by an iron ore screening granulator, a flue gas purification dryer and an iron ore crushing and screening machine to obtain dried iron ore granular materials with the grain size of 6-40 mm; treating the prepared reducing agent coking coal by a coking coal ball press machine and a flue gas purification dryer to obtain dried coking coal balls with the particle size of 45-55 mm, and enabling the dried coking coal balls to fall into a coking coal ball bin; uniformly mixing the obtained dried coking coal balls and the obtained dried iron ore particle materials with the particle size of 6-40 mm according to the mass percent of 30% by a mixing output device to obtain mixed materials, and inputting the mixed materials into a distributing machine of a coal-based direct reduction roasting kiln; the weight percentage of the water of the mixed material is less than 10 percent.

S2: coal-based coking, reducing and roasting: the coal-based coking reduction roasting system is a coal-based coking reduction roasting kiln; it includes the kiln body, the internal snakelike flue that is circuitous that is provided with 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; 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, and an outlet of the roasting preheating section is connected with a flue gas waste heat utilization device; the bottom of the roasting preheating section is communicated with a vertical blanking channel; the blanking channel penetrates through the roasting heating section, the roasting reduction section and the heat preservation reduction connecting section and is isolated from a roasting heating section flue and a roasting reduction section flue; the bottom end of the blanking channel is communicated with an air cooling pipe for cooling materials, and the outer wall of the upper end of the air cooling pipe is provided with an air supply preheater and a cooling hot air collector; the roasting temperature range in the roasting reduction section flue is 960-1080 ℃, the temperature rise speed of the roasting reduction section flue gas is less than or equal to 2 ℃/min, when the roasting reduction section flue gas temperature is 900-960 ℃, the material guide impeller is started to start feeding, and the feeding speed is v 1; the iron ore mixed material slowly descends along a preheating material pool, a preheating material pipe and a blanking channel under the control of a material guide impeller, and when the temperature of flue gas in a roasting reduction section reaches 960-1080 ℃, the blanking speed is v 2; v2 is 5-6 times of v 1; iron ore particle materials are flatly paved in a preheating material pool to be stacked with the thickness of 200-300 mm; the iron ore particle materials after coking, reduction and roasting fall into an air cooling pipe to be cooled to 45-55 ℃, and the iron ore particle materials pass through a material guide platform under the control of a material guide impeller to fall into a roasting bin, so that a coking, reduction and roasting material is obtained; is input into the coke separation system through an output device.

S3: coke separation: and separating coke from the obtained coking reduction roasting material by a screening magnetic separator, and allowing the coke to fall into a coke separating bin to obtain a reduced material which enters a circulating grinding system.

S4: and (3) circulating grinding: the reducing materials sequentially pass through a crusher, a pair roller mill, a magnetic separator, a Raymond mill, a screening and pumping machine and a hoister, then return to the pair roller mill for circularly grinding, pumping ash and removing dust, and finally obtain the reduced iron powder with the particle size of more than 300 meshes through the screening and pumping machine.

S5: magnetic separation optimization: the obtained reduced iron powder with the grain size of more than 300 meshes passes through a medium magnetic concentration machine, and finally the optimized iron fine powder with the grain size of more than 300 meshes falls into an optimized iron fine powder bin.

Preferably, the flue gas waste heat utilization device collects flue gas generated by coal-based coking reduction roasting, and introduces the flue gas into a flue gas purification dryer to heat and dry the raw material.

Preferably, the raw materials are processed to obtain a mixed particle material; the contact area of particle gap coking convection reduction is increased, the gas overflow holding space is sufficient, and the convection reduction gas is sufficient.

Preferably, the coal-based coking reduction roasting carries out the same way with the roasting heating flue gas and the blanking reduction, the roasting heating peroxide is sufficient, and the blanking reduction gas is sufficient; the reduction temperature range is 900-980 ℃ low-temperature reduction, the air supply preheating temperature of the air supply preheater is 320-380 ℃, and the smoke discharge temperature of the roasting preheating section is 160-200 ℃.

Preferably, the coal-based coking reduction roasting is to press the prepared coking coal into coking coal balls with the particle size of 45-55 mm as a reducing agent to coke and reduce and roast coke.

Preferably, the coal-based coking is subjected to reduction roasting, the iron ore is subjected to reduction catalysis coking coal coking, the reduction gas is sufficient, and the coking reduction atmosphere is sufficient.

Preferably, the coal-based coking reduction roasting is carried out, the roasting material is directly contacted with the heating flue gas in the roasting preheating section, and the roasting material fully absorbs the heat energy of the flue gas, and water is quickly evaporated and discharged along with the flue gas.

Preferably, the coal-based coking, reducing and roasting is carried out, the reduced gas overflows into the serpentine flue from the gas overflow port after reduction in the heating section, the excessive reducing gas overflows into the serpentine flue (the temperature is higher than 850 ℃) and is fully combusted with the excessive air in the serpentine flue in time, and the concentration of the reducing gas in the blanking channel is increased in time.

Preferably, the coal-based coking reduction roasting controls the blanking through the rotating speed of the guide impeller, the coking time of coking coal and the reduction time of iron ore can be adjusted in time according to the requirements of full coking reduction, and the reduction time of coking coal and coking iron ore is full.

Preferably, the coal-based coking reduction roasting preheats air supply by using the cooling heat energy of the roasting material through an air supply preheater, and the temperature of the preheated air supply is 320-380 ℃.

Preferably, the coal-based coking reduction roasting is carried out, and roasting heating flue gas is snakelike circuitous heating from bottom to top along the set snake-shaped flue of the reduction section, the snake-shaped flue of the heating section and the snake-shaped flue of the preheating section in a snakelike way layer by layer and slowly and naturally goes upward without induced draft power consumption; the snakelike flue gas holds the big heat-retaining energy storage of space, both sides wall heating is even.

Preferably, the reduction blanking is directly under the gravity of the blanking channel, the roasted particle mixed material slowly and naturally descends under the control of the material guide impeller, the reduction gas is slowly and naturally ascended along with the coking and reduction heating of the blanking gap, and the coal-based convection coking reduction reaction is naturally formed in the blanking channel.

Preferably, the magnetic separation is optimized without water, and the water resource consumption is saved.

Preferably, the cyclic grinding is performed by forming cyclic grinding ash extraction dust removal on the roller mill → the magnetic separator → the Raymond mill → the screening extractor → the hoisting machine → the roller mill.

A device for optimizing iron ore by magnetic separation of coal-based coking reduction roasting coke comprises a raw material treatment flue gas waste heat utilization system, a coal-based coking reduction roasting system, a coke separation system, a circulating grinding system, a magnetic separation optimization system and an ash removal and dust removal system;

the raw material treatment flue gas waste heat utilization system comprises an iron ore crushing granulator, a coking coal ball press machine, a flue gas purification dryer, a flue gas waste heat utilization device, an iron ore screening machine, a coking coal ball bin and a mixed material output device which are sequentially connected.

The coal-based coking, reducing and roasting system is a coal-based coking, reducing and roasting kiln and comprises a kiln body, wherein a preheating material pool, a preheating material pipe, a snakelike flue, an air cooling pipe, a material guiding impeller, a material guiding platform, a material bin and an output device are arranged in the kiln body from top to bottom; the snakelike flue comprises a roasting preheating section, a roasting heating section and a roasting reduction section from top to bottom, and the blanking channel penetrates through the snakelike flue from top to bottom and is communicated with the roasting preheating section.

The coke separation system comprises a screening magnetic separator and a coke separation bin; the circulating grinding system comprises a crusher, a pair roller mill, a medium magnetic separator, a Raymond mill, a screening extractor, a lifter and a pair roller mill circulating grinding device; the magnetic separation optimization system comprises a medium magnetic separator and an optimized iron fine powder bin; the ash and dust removing system comprises an ash and dust removing device and an electrostatic dust removing device.

The inlet of the flue gas waste heat utilization device is connected with the outlet of the roasting preheating section through a hot flue gas pipeline; and the outlet of the mixed material output device is connected with a material distributor above the kiln body.

The output device is connected with the screening magnetic separator; the screening magnetic separator is connected with the crusher; the screening and extracting machine is connected with the medium magnetic separator.

The ash and dust removing device is respectively connected with the raw material treatment flue gas waste heat utilization system, the coke separation system, the pulverizer of the circulating grinding system, the screening extractor and the magnetic separation optimization system.

Further, the iron ore screening granulator is connected with the iron ore crushing and screening machine through a flue gas purification dryer; the coking coal ball press machine is connected with the coking coal ball bin through a flue gas purification dryer.

Further, the iron ore crushing and screening machine (fine ore return) is connected with an inlet of the iron ore screening granulator.

Furthermore, the inlet of the flue gas waste heat utilization device is connected with the outlet of the snakelike flue through a hot flue gas pipeline, and the other end of the flue gas waste heat utilization device is connected with the inlet of the flue gas purification dryer.

Furthermore, the coal-based coking reduction roasting kiln is characterized in that a snake-shaped flue is communicated with the blanking channel at the roasting preheating section.

Further, the coal-based coking reduction roasting kiln, the air supply preheater and the cooling hot air collector are arranged on the outer wall of the upper end of the air cooling pipe; the inlet end of the air supply preheater is connected with the outlet of the cooling hot air collector, and the outlet end of the air supply preheater is connected with a burner of the combustion chamber; the inlet of the snake-shaped flue is connected with the combustion chamber, and the outlet end of the snake-shaped flue is connected with the flue gas waste heat utilization device.

Furthermore, the coal-based coking reduction roasting kiln is characterized in that a supporting beam is arranged between the lower portion of the flue and the bottom surface of the kiln body, a backing ring is arranged below the bottom surface of the kiln body, and a supporting column is arranged between the backing ring and the ground.

Further, the bottom surface of the coal-based coking reduction roasting kiln is made of a steel plate.

Further, in the coal-based coking reduction roasting kiln, the preheating pipe is a square steel pipe.

Further, the coal-based coking reduction roasting kiln is characterized in that the lower end of the serpentine flue is connected with the heating chamber and the burner, the side wall of the heating chamber is provided with a fire observation hole, and the side wall of the heating chamber above the fire observation hole is provided with a temperature monitoring device.

Furthermore, the coal-based coking reduction roasting kiln is provided with a partition plate between the roasting heating section and the roasting preheating section, and flanges are symmetrically arranged in the roasting heating section and the roasting preheating section at the tail end of the partition plate.

Further, the coal-based coking reduction roasting kiln is provided with a partition plate between the roasting reduction section and the roasting heating section, and a flange is arranged at the tail end of the partition plate towards the roasting reduction section.

Further, the side wall of the roasting heating section of the coal-based coking reduction roasting kiln is provided with a heating section reduced gas overflow port.

Further, the coal-based coking reduction roasting kiln is characterized in that a gas overflow port after reduction of the heating section is communicated with the roasting heating section.

Furthermore, a temperature monitoring device is arranged through the side wall of the roasting reduction section and the side wall of the kiln body in the coal-based coking reduction roasting kiln.

Furthermore, the coal-based coking reduction roasting kiln is provided with communicated heat-preservation sealing gaps between the side wall of the kiln body and the preheating distribution tank and between the side wall of the kiln body and the roasting system.

Further, the coal-based coking reduction roasting kiln is characterized in that a kiln body is a hollow shell, a preheating material pool is concavely arranged in the middle of the top wall of the kiln body towards the inner side of the kiln body, and a material distributor is arranged above the preheating material pool; the air-cooled pipe is characterized in that a material guide impeller is arranged below the tail end of the air-cooled pipe, a material guide platform is arranged below the material guide impeller, a material bin is arranged below the material guide platform, and an output device is arranged below the material bin.

Further, the cyclic grinding: paired roller mill → magnetic separator → Raymond mill → screening extractor → elevator → paired roller mill.

Furthermore, the ash and dust removing device is respectively connected with the raw material treatment flue gas waste heat utilization system, the coke separation system, the pulverizer of the circulating grinding system, the screening extractor and the magnetic separation optimization system.

Compared with the prior art, the invention has the following beneficial effects:

1) for raw material treatment flue gas waste heat utilization: the raw materials are heated and dried by using the residual heat of the flue gas of the coal-based coking reduction roasting kiln, the flue gas residual heat utilization device introduces the hot flue gas into a flue gas purification and heating dryer, the flue gas flows through gaps of raw material particles, tiny dust and harmful substances in the flue gas are bonded and adsorbed by the raw material particles, and the tiny dust and the harmful substances are removed by way of dust extraction in the screening process, so that the pollution is reduced, and the environmental protection investment is reduced; the raw material particles become the flue gas purification filler, and the flue gas is purified and environment-friendly; the temperature of the purified flue gas is less than 60 ℃, the raw material is dried, and the utilization efficiency of the waste heat of the flue gas is obviously improved; the iron ore screening process is incidentally with in time taking out the ash and getting rid of part impurity dust in the iron ore to take out the ash and remove dust and select the waste material with harmful impurity, production process environmental protection, the calcination heating energy consumption reduces, obtains the granule material, and the coking coal ball mixes with the iron ore granule according to a proportion, obtains the granule compounding.

Screening iron ores: by the iron ore screening, part of impurities (5-10%) in the iron ore are directly removed by ash pumping, harmful impurities are removed by ash pumping and dust removal, waste materials are selected, iron ore powder with the particle size of less than 6mm is returned for granulation, and dry iron ore particle materials with the particle size of 6-40 mm are obtained; the consumption of natural gas for roasting and heating is obviously reduced by more than 5 percent.

Mixing material particle gaps: the reduction contact area is increased, and the reduction gas retention space is sufficient; secondly, the roasting material can absorb the heat energy of the flue gas, the moisture can be evaporated quickly and discharged along with the flue gas in time, and the consumption of roasting and heating natural gas is reduced obviously; thirdly, the gas after reduction naturally ascends and escapes in time, and the concentration of the reduction gas is increased in time; fourthly, the coal-based coking convection reduction reaction is naturally formed in the blanking channel of the roasting kiln; the gas after reduction can overflow into the snake-shaped flue; and sixthly, the excess reducing gas and the excess air can be conveniently and sufficiently combusted in the serpentine flue in time, and the utilization efficiency of the circulating heat energy is improved.

Reducing agent coke briquette: the roasting reduction iron ore is reduced to catalyze coking coal coking, the convection coking reduction efficiency is obviously improved, and the coking reduction atmosphere is full.

2) For the coal-based coking reduction roasting process: the coal-based coking, reducing and roasting, wherein roasting and heating flue gas and blanking reduction are performed respectively, the reduction temperature range is 900-980 ℃, the low-temperature reduction is performed, and the smoke discharging temperature is 160-200 ℃; the cooling heat energy of the roasting material preheats and supplies air, the preheating temperature of the air supply is 320-380 ℃, and the recycling efficiency of the cooling heat energy of the roasting material is obviously improved; the raw materials are heated and dried by using the waste heat of the flue gas, the temperature of the discharged flue gas is less than 60 ℃ after the heating and drying, and the loss of the heat energy of the discharged flue gas is obviously reduced; the temperature of the external body of the kiln is close to the normal temperature, so that the heat dissipation loss is greatly reduced; heating the heating smoke layer by layer along the serpentine flue and naturally ascending; the reduction blanking is directly downward along the gravity of the blanking channel, and the material guide impeller controls the power consumption of the blanking to be minimum.

S-shaped flue: the two side walls of the snake-shaped flue are heated, heat storage and energy storage are uniformly heated, the roasting heating flue gas slowly goes upwards from the snake-shaped natural heating of the reduction section, the heating section and the preheating section along the snake-shaped flue of the reduction section, the snake-shaped flue of the heating section and the snake-shaped flue of the preheating section, and the heat exchange efficiency is obviously improved.

Coal-based coking, reducing and roasting: a partition plate is arranged between the roasting reduction section and the roasting heating section, 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 coal-based reduction roasting is carried out, the reduction temperature, the reduction gas concentration and the reduction time are respectively controlled, the mutual influence among various control parameters is relatively weak, the high-degree natural coordination control can be realized, the thermotechnical control is accurate and easy to control, and the convection reduction atmosphere is sufficient; internal and external preheating and heating in the roasting process, utilization of waste heat of flue gas, cyclic utilization of cooling heat energy of roasted materials, coal gasification by iron ore reduction catalysis coke, timely and sufficient combustion of excess reducing gas and obvious reduction of roasting heating natural gas consumption.

A roasting preheating section: the roasting material falls into a blanking channel of the preheating section, and the roasting material is directly contacted with the heating flue gas, fully absorbs the heat energy and the moisture of the flue gas (the temperature is more than 200 ℃), quickly evaporates and is timely discharged along with the flue gas.

A roasting heating section: the roasting material falls into the heating section blanking channel, the reduced gas and the excessive reducing gas overflow into the serpentine flue from the heating section overflow port, the concentration of the reducing gas is increased in time, the excessive reducing gas (the temperature is more than 850 ℃) and the excessive air in the serpentine flue are combusted fully in time, the investment and the cost of flue gas treatment equipment are saved, the environment is friendly, and the timely recycling efficiency of heat energy is obviously improved.

A roasting reduction section: the roasted material falls into a blanking channel of the reduction section, the reduction temperature of the roasted material is higher than 930 ℃, the iron ore is reduced and catalyzes coking coal to coke, and the reduction gas is sufficient and surplus; the reduced gas overflows into the snakelike flue to be burnt in time, and the concentration of the reduced gas in the blanking channel is increased in time; the roasting material slowly descends along with the rotating speed of the material guide impeller, the reducing gas is reduced and heated along with the blanking gap to slowly and naturally ascend, and the coal-based coking reduction convection reaction is naturally formed in the blanking channel.

And (3) insulating and reducing the connecting section: the roasted material falls into a material channel of the heat-preservation reduction connection section, the temperature of the roasted material is higher than 930 ℃, the reduction temperature is kept well, the concentration of the reduction gas is sufficient, the reduction time is sufficient, and the convection coking reduction reaction is more sufficient.

Air cooling of the roasting material: the roasting material is cooled in the air cooling pipe, so that the roasting material is prevented from being oxidized again, water is not used for magnetic separation optimization, water resource consumption is saved, and the regional adaptability is strong; and (3) enabling the roasting material to fall into an air cooling pipe, and naturally cooling the air cooling pipe to about 45-55 ℃ to obtain the coking reduction roasting material.

3) Coke separation: screening the obtained coking reduction roasting material by a magnetic separator; separating the coke and dropping the coke into a coke separating bin; and feeding the obtained reduced material into a circulating grinding system.

4) And (3) circulating grinding: the coking reduction temperature is reduced at 900-980 ℃, and the reduced materials are easily ground to be more than 300 meshes, so that the dust removal efficiency of circular grinding and ash pumping is obviously improved. And (3) circularly grinding the obtained reduced material by a crusher, a double-roller mill → a magnetic separator → a Raymond mill → a screening extractor → a lifting machine → the double-roller mill, ash pumping and dust removing, and obtaining the reduced iron powder with the particle size of more than 300 meshes by the screening extractor.

5) Magnetic separation optimization: the magnetic separation optimization does not use water, so that the water resource consumption is saved, and the regional adaptability is strong; the obtained reduced iron powder with the grain size of more than 300 meshes passes through a medium magnetic concentration device, and the obtained optimized iron fine powder with the grain size of more than 300 meshes falls into an optimized iron fine powder bin.

6) Ash and dust removal: the ash and dust removing device not only can be used for extracting ash and removing dust, removing impurities and reducing the abrasion of the induced draft fan, but also can be used for providing system negative pressure for the magnetic separation optimization process; the electrostatic dust collection device further improves the dust collection efficiency.

The method is suitable for treating various types of iron oxide ores with Fe higher than 38%, the various types of iron oxide ores can be mixed and roasted, the recovery rate of iron is not influenced by magnetic separation optimization, the grade of the optimized iron concentrate powder prepared by the method is Fe higher than 76%, the harmful impurity removal effect is obvious, the sulfur and phosphorus removal efficiency is higher than 60%, 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, coking, 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, and particularly has more advantages from the source of improving the quality structure and energy structure of steel products and saving energy and reducing emission.

Drawings

FIG. 1 is a main sectional view of the structure of the coal-based coking 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 flow chart of magnetic separation optimization of iron ore by coal-based coking reduction roasting coke.

101-iron ore screening and granulating machine, 102-coking coal ball press machine, 103-flue gas purification dryer, 104-flue gas waste heat utilization device, 105-iron ore crushing and screening machine, 106-coking coal ball bin and 107-mixed material output device.

201-a kiln body, 202-a preheating material pool, 203-a preheating material pipe, 204-a blanking channel, 205-a roasting preheating section, 206-a roasting heating section, 207-a roasting reduction section, 208-a heat preservation reduction connecting section, 209-an air cooling pipe, 210-a material guide impeller, 211-a material guide platform, 212-a storage bin, 213-an output device, 214-a heat preservation sealing gap, 215-an air supply preheater, 216-a cooling hot air collector, 217-a supporting beam, 218-a backing ring, 219-a supporting column, 220-a material distributor, 221-a serpentine flue, 222-a temperature monitoring device, 223-a fire observation hole, 224-a combustion chamber and 225-a gas overflow port after reduction of the heating section.

301-screening magnetic separator and 302-separating coke bin.

401-crusher, 402-pair roller mill, 403-medium magnetic separator, 404-Raymond mill, 405-screening extractor and 406-elevator.

501-middle magnetic concentration machine, 502-optimized iron fine powder bin, 601-ash and dust removing device and 602-electrostatic dust removing 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, a device for magnetic separation optimization of iron ore by coal-based coking, reduction and roasting of coke mainly comprises 6 parts: the system comprises a raw material treatment flue gas waste heat utilization system, a coal-based coking reduction roasting kiln, a coke separation system, a circulating grinding system, a magnetic separation optimization system and an ash removal and dust removal system.

1) Raw materials processing flue gas waste heat utilization system: the device comprises an iron ore screening granulator 101, a coking coal ball press 102, a flue gas purification dryer 103, a flue gas waste heat utilization device 104, an iron ore crushing and screening machine 105, a coking coal ball bin 106 and a mixed material output device 107 which are connected in sequence.

The iron ore screening granulator 101 is connected with an iron ore crushing and screening machine 105 through a flue gas purification dryer 103; the coking coal ball press 102 is connected with a coking coal ball bin 106 through a flue gas purification dryer 103.

The inlet of the flue gas waste heat utilization device 104 is connected with the outlet of the snakelike flue 221 through a hot flue gas pipeline, and the other end of the flue gas waste heat utilization device is connected with the inlet of the flue gas purification dryer 103; the iron ore screening machine 105 is connected with the iron ore screening granulator 101; the outlet of the mixed material output device 107 is connected with a distributing machine 220 of the coal-based coking reduction roasting kiln.

2) Coal-based coking reduction roasting kiln: as shown in fig. 1-2, wherein: the kiln body 201 is hollow shell, and the kiln body 201 is internal from top to bottom to have circuitous snakelike flue 221 with the brickwork, and snakelike flue 221 both sides wall heating is even, and snakelike flue 221 from the top down divide into the three-layer, is in proper order: a preheating material pool 202 is concavely arranged at the middle part of the top wall of the kiln body 201 towards the inner side of the kiln body 201 in the roasting preheating section 205, the roasting heating section 206, the roasting reduction section 207 and the top wall of the kiln body 201, a distributing machine 220 is arranged above the preheating material pool 202, and the distributing machine 220 is connected with the mixed material output device 107; the mixed material passing through the raw material processing system is sent to the preheating material pool 202 through the distributing machine 220; a plurality of preheating pipes 203 are uniformly arranged on the bottom surface of the preheating material pool 202, the preheating material pool 202 is communicated with the roasting preheating section 205 through the preheating pipes 203, the bottom of the roasting preheating section 205 is communicated with a vertical blanking channel 204, and the blanking channel 204 passes through the roasting heating section 206, the roasting reduction section 207 and the heat-preservation reduction connecting section 208 and is isolated from the roasting heating section 206 and the roasting reduction section 207; the bottom end of the blanking channel 204 is communicated with an air cooling pipe 209 for cooling materials; an air supply preheater 215 and a cooling hot air collector 216 are arranged on the outer wall of the upper end of the air cooling pipe 209; the inlet of the supply air preheater 215 is connected to the cooling hot air collector 216 at one end and to the burner of the combustion chamber 224 at the other end. The side wall of the upper part of the blanking channel 204 at the roasting heating section 206 is uniformly provided with a heating section reduced gas overflow port 225; the roasting reduction section 207 is connected with a burner of a combustion chamber 224; the side wall of the roasting reduction section 207 is provided with a fire observation hole 223, and a temperature monitoring device 222 is arranged above the fire observation hole 223.

A partition plate is arranged between the roasting reduction section 207 and the roasting heating section 206, and a flange is arranged at the tail end of the partition plate towards the roasting reduction section 207; a partition plate is arranged between the roasting heating section 206 and the roasting preheating section 205, and flanges are symmetrically arranged in the roasting heating section 206 and the roasting preheating section 205 at the tail end of the partition plate; communicated heat-preservation sealing gaps 214 are arranged between the side wall of the kiln body 201 and the preheating material pool 202 and between the side wall of the kiln body 201 and the roasting system; a heat-preservation reduction connecting section 208 is supported below the roasting reduction section 207, a supporting beam 217 is arranged between the lower part of the heat-preservation reduction connecting section 208 and the bottom surface of the kiln body 201, a backing ring 218 is arranged below the bottom surface of the kiln body 201, and a supporting column 219 is arranged between the backing ring 218 and the ground.

A material guiding impeller 210 is arranged below the tail end of the air cooling pipe 209, a material guiding platform 211 is arranged below the material guiding impeller 210, a storage bin 212 is arranged below the material guiding platform 211, and an output device 213 is arranged below the storage bin 212; the coked-reduced roasted material is sent to a coke separation system through an output device 213.

3) A coke separation system: comprises a screening magnetic separator 301 and a coke separating bin 302. The inlet of the sieving magnetic separator 301 is connected with the output device 213; the screening magnetic separator 301 is connected with a crusher 401.

4) A circulating grinding system: comprises a crusher 401, a double-roller mill 402, a medium magnetic separator 403, a Raymond mill 404, a screening and pumping machine 405 and a hoister 406 which are connected in sequence. The circulating grinding: the roll mill 402 → the magnetic separator 403 → the Raymond mill 404 → the sifting extractor 405 → the elevator 406 → the roll mill 402 is cyclically ground. Obtaining a reduced material with a particle size of more than 300 meshes by a sieving and separating machine 405;

5) magnetic separation optimizing system: comprises a medium magnetic separator 501 and an optimized iron fine powder bin 502; the discharge port of the screening and extracting machine 405 is connected with the inlet of the middle magnetic separator 501.

6) Ash and dust removing system: comprises an ash-removing and dust-removing device 601 and an electrostatic dust-removing device 602; the ash-removing and dust-removing device 601 is respectively connected with the raw material treatment flue gas waste heat utilization system, the coke separation system, the pulverizer 401 of the circulating grinding system, the screening extractor 405 and the magnetic separation optimization system.

Specifically, the method comprises the following steps:

example 1

Some iron oxide ore contains iron tfe 38.94%. The method comprises the following steps:

(1) raw material treatment: screening and granulating, heating and drying, crushing and screening iron ore with TFe38.94% to obtain dry iron ore granular material with the particle size of 6-40 mm; performing coking coal ball pressing and heating drying treatment on the prepared coking coal to obtain dried coking coal balls with the particle size of 45-55 mm; and uniformly mixing the dried coking coal balls with the particle size of 45-55 mm with iron ore particles with the particle size of 6-40 mm according to the mass percentage of 30% to obtain an iron ore particle mixed material, wherein the water content of the mixed material is less than 10% by weight.

(2) Coal-based coking reduction roasting kiln: filling a coal-based coking reduction roasting test kiln with the iron ore particle mixed material; the thickness of the materials is tiled and stacked in a preheating material pool and is 200-300 mm; starting a burner of a combustion chamber, heating at a heating temperature rise speed of less than or equal to 2 ℃/min, starting a material guide impeller to perform blanking at 1 r/h when the temperature of flue gas at a reduction section reaches 900-960 ℃, adjusting the blanking speed to 5-6 r/h when the temperature of the flue gas at the reduction section rises to 960-1080 ℃, cooling an iron ore mixed material to 45-55 ℃ after coking reduction roasting, and allowing the iron ore mixed material to pass through a material guide platform and fall into a roasting bin under the control of the material guide impeller to obtain the coking reduction roasting material.

(3) Coke separation: separating coke from the coking reduction roasting material by a screening magnetic separator to obtain the coke with 0.82% of volatile matter, wherein the quality strength of the coke meets the steel-making requirement; simultaneously obtaining a reduced material;

(4) and (3) circulating grinding: and (3) circularly grinding, ash pumping and dust removing the reduced material by a crusher, the paired roller mill → a magnetic separator → a screening extractor → a lifter → the paired roller mill, and obtaining the reduced material with the granularity of more than 300 meshes by the screening extractor.

(5) Magnetic separation optimization: and (3) refining the obtained reduced material with the granularity of more than 300 meshes by a medium-magnetic refiner to obtain optimized iron concentrate powder: fe78.01%, P0.016% and S0.019%; the content of other impurities meets the production requirement of the reduced iron.

Example 2

Some iron oxide ore contains iron tfe 56.72%. The method comprises the following steps:

(1) raw material treatment: granulating, drying, crushing and screening iron ore with TFe56.72% to obtain dry iron ore granular materials with the particle size of 6-40 mm; performing coking coal briquetting and drying treatment on the prepared coking coal to obtain dried coking coal briquettes with the particle size of 45-55 mm; and uniformly mixing the dried coking coal balls with the particle sizes of 45-55 mm with iron ore particles with the particle sizes of 6-40 mm according to the mass percentage of 30% to obtain an iron ore particle mixed material, wherein the water content of the mixed material is less than 10% by weight.

(2) Coal-based coking reduction roasting kiln: and roasting the iron ore particle mixed material in a coal-based coking reduction roasting test kiln to obtain a coking reduction roasting material.

(3) Coke separation: separating coke from the coking reduction roasting material by a screening magnetic separator to obtain the coke with 0.74 percent of volatile matter, wherein the quality strength of the coke meets the steel-making requirement; simultaneously obtaining a reduced material;

(5) Magnetic separation optimization: and (3) refining the obtained reduced material with the granularity of more than 300 meshes by a medium-magnetic refiner to obtain optimized iron concentrate powder: fe81.61%, phosphorus P0.017% and sulfur 0.018%; the content of other impurities meets the production requirement of the reduced iron.

Example 3

Certain magnetite oxides contain iron TFe24.57%. The method comprises the following steps:

(1) raw material treatment: carrying out granulation, drying, crushing and screening treatment on TFe24.57% magnetite to obtain a dry iron ore particle material with the particle size of 6-40 mm; performing coking coal briquetting and drying treatment on the prepared coking coal to obtain dried coking coal briquettes with the particle size of 45-55 mm; and uniformly mixing the dried coking coal balls with the particle sizes of 45-55 mm with iron ore particles with the particle sizes of 6-40 mm according to the mass percentage of 30% to obtain an iron ore particle mixed material, wherein the water content of the mixed material is less than 10% by weight.

(3) Coke separation: separating coke from the coking reduction roasting material by a screening magnetic separator to obtain the coke with 0.79% of volatile matter, wherein the quality strength of the coke meets the steel-making requirement; simultaneously obtaining a reduced material;

(5) Magnetic separation optimization: and (3) refining the obtained reduced material with the granularity of more than 300 meshes by a medium-magnetic refiner to obtain optimized iron concentrate powder: fe77.59%, phosphorus-containing P0.014%, sulfur-containing 0.015%; the content of other impurities meets the production requirement of the reduced iron.

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

1. A method for optimizing iron ore by magnetic separation of coal-based coking reduction roasting coke is characterized by comprising the following steps:

s1: flue gas waste heat utilization in raw material treatment: treating iron ore by an iron ore screening granulator (101), a flue gas purification dryer (103) and an iron ore crushing and screening machine (105) to obtain dry iron ore particle materials with the particle size of 6-40 mm; treating the prepared reducing agent coking coal by a coking coal ball press (102) and a flue gas purification dryer (103) to obtain dried coking coal balls with the particle size of 45-55 mm, and dropping the dried coking coal balls into a coking coal ball bin (106); uniformly mixing the obtained dry coking coal balls and the obtained dry iron ore particle materials with the particle size of 6-40 mm according to the mass percentage of 30% through a mixed material output device (107) to obtain mixed materials, and inputting the mixed materials into a distributing machine (220) of a coal-based direct reduction roasting kiln; the weight percentage of the water of the mixed material is less than 10 percent;

s2: coal-based coking, reducing and roasting: the coal-based coking reduction roasting system is a coal-based coking reduction roasting kiln; it includes the kiln body (201), be provided with circuitous snakelike flue (221) from top to bottom in the kiln body (201), snakelike flue (221) from the top down divide into the three-layer, do in proper order: a roasting preheating section (205), a roasting heating section (206) and a roasting reduction section (207); a preheating material pool (202) is arranged above the roasting preheating section (205), the preheating material pool (202) is communicated with the roasting preheating section (205) through a preheating pipe (203), and an outlet of the roasting preheating section (205) is connected with a flue gas waste heat utilization device (104); the bottom of the roasting preheating section (205) is communicated with a vertical blanking channel (204); the blanking channel (204) passes through the roasting heating section (206), the roasting reduction section (207) and the heat-preservation reduction connecting section (208), and is isolated from the roasting heating section (206) flue and the roasting reduction section (207) flue; the bottom end of the blanking channel (204) is communicated with an air cooling pipe (209) for cooling materials, and the outer wall of the upper end of the air cooling pipe (209) is provided with an air supply preheater (215) and a cooling hot air collector (216); the roasting temperature range in the flue of the roasting reduction section (207) is 960-1080 ℃, the temperature rise speed of the flue gas of the roasting reduction section (207) is less than or equal to 2 ℃/min, when the flue gas temperature of the roasting reduction section (207) is 900-960 ℃, the material guide impeller (210) is started to start feeding, and the feeding speed is v 1; the iron ore mixed material slowly descends along a preheating material pool (202), a preheating material pipe (203) and a blanking channel (204) under the control of a material guide impeller (210), and when the flue gas temperature of a roasting reduction section (207) reaches 960-1080 ℃, the blanking speed is v 2; v2 is 5-6 times of v 1; iron ore particle materials are flatly paved and stacked in a preheating material pool (202) to have the thickness of 200-300 mm; the iron ore particle materials after coking, reduction and roasting fall into an air cooling pipe (209) to be cooled to 45-55 ℃, and the iron ore particle materials pass through a material guide platform (211) and fall into a roasting bin (212) under the control of a material guide impeller (210) to obtain a coking, reduction and roasting material; inputting the coke separation system through an output device (213);

s3: coke separation: separating coke from the obtained coking reduction roasting material by a screening magnetic separator (301) and allowing the coke to fall into a coke separating bin (302) to obtain a reduction material, and allowing the reduction material to enter a circulating grinding system;

s4: and (3) circulating grinding: the reduced materials sequentially pass through a crusher (401), a double-roller mill (402), a magnetic separator (403), a Raymond mill (404), a screening and pumping machine (405) and a hoisting machine (406) and then return to the double-roller mill (402) for circular grinding, ash pumping and dust removal, and reduced iron powder with the particle size of more than 300 meshes is obtained through the screening and pumping machine (405);

s5: magnetic separation optimization: the obtained reduced iron powder with the grain size of more than 300 meshes passes through a medium magnetic concentration machine (501), and finally the optimized iron fine powder with the grain size of more than 300 meshes falls into an optimized iron fine powder bin (502).

2. The method for magnetic separation optimization of iron ore by coal-based coking, reducing and roasting coke according to claim 1, characterized in that the preheating air supply temperature of the air supply preheater (215) is 320-380 ℃, and the exhaust gas temperature of the roasting preheating section (205) is 160-200 ℃.

3. The method for magnetic separation optimization of iron ore by coal-based coking reduction roasting coke according to claim 1, characterized in that the coal-based coking reduction roasting, the reduced gas overflows from a gas overflow port (225) after reduction of the heating section into a roasting heating section (206); the excess reducing gas overflows into the serpentine flue (221) and the serpentine flue (221) to fully combust the excess air; the concentration of the reducing gas in the blanking channel (204) is increased, and the temperature of the excessive reducing gas is more than 850 ℃.

4. The method for magnetic separation optimization of iron ore by coal-based coking, reducing and roasting coke according to claim 1, characterized in that the coal-based coking, reducing and roasting uses the roasting material cooling heat energy to preheat the air supply through an air supply preheater (215), and the temperature of the preheated air supply is 320-380 ℃.

5. The device for magnetic separation optimization of iron ore by coal-based coking, reducing and roasting coke for the method according to any one of claims 1 to 4, which is characterized by comprising a raw material treatment flue gas waste heat utilization system, a coal-based coking, reducing and roasting system, a coke separation system, a circulating grinding system, a magnetic separation optimization system and an ash removal and dust removal system;

the raw material treatment flue gas waste heat utilization system comprises an iron ore crushing granulator (101), a coking coal ball press (102), a flue gas purification dryer (103), a flue gas waste heat utilization device (104), an iron ore screening machine (105), a coking coal ball bin (106) and a mixed material output device (107) which are connected in sequence;

the coal-based coking, reducing and roasting system is a coal-based coking, reducing and roasting kiln and comprises a kiln body (201), wherein a preheating material pool (202), a preheating material pipe (203), a snakelike flue (221), an air cooling pipe (209), a material guide impeller (210), a material guide platform (211), a storage bin (212) and an output device (213) are arranged in the kiln body (201) from top to bottom; the snakelike flue (221) comprises a roasting preheating section (205), a roasting heating section (206) and a roasting reduction section (207) from top to bottom, and the warm blanking channel (204) penetrates through the snakelike flue (221) from top to bottom and is communicated with the roasting preheating section (205);

the coke separation system comprises a screening magnetic separator (301) and a coke separation bin (302); the circulating grinding system comprises a crusher (401), a counter-roll mill (402), a medium magnetic separator (403), a Raymond mill (404), a screening and pumping machine (405), a lifting machine (406) and a counter-roll mill (402) circulating grinding device; the magnetic separation optimization system comprises a medium magnetic separator (501) and an optimized iron fine powder bin (502); the ash and dust removing system comprises an ash and dust removing device (601) and an electrostatic dust removing device (602);

an inlet of the flue gas waste heat utilization device (104) is connected with an outlet of the roasting preheating section (205) through a hot flue gas pipeline; an outlet of the mixed material output device (107) is connected with a material distributor (220) above the kiln body (201);

the output device (213) is connected with the screening magnetic separator (301); the screening magnetic separator (301) is connected with the crusher (401); the screening and extracting machine (405) is connected with a medium magnetic separator (501);

the ash and dust removing device (601) is respectively connected with a raw material treatment flue gas waste heat utilization system, a coke separation system, a pulverizer (401) of a circulating grinding system, a screening extractor (405) and a magnetic separation optimization system.

6. The device for magnetic separation optimization of iron ore by coal-based coking, reducing and roasting coke according to claim 5, characterized in that the outlet end of the flue gas waste heat utilization device (104) is connected with the inlet of the flue gas purification dryer (103).

7. The device for magnetic separation optimization of iron ore by coal-based coking, reducing and roasting coke according to claim 5, characterized in that the heating section reduced gas overflow ports (225) are arranged on the upper parts of the side walls of the blanking channel (204) of the roasting heating section (206), and the heating section reduced gas overflow ports (225) are communicated with the roasting heating section (206).

8. The device for magnetic separation optimization of iron ore by coal-based coking, reduction and roasting of coke according to claim 5, characterized in that the inlet end of the serpentine flue (221) is connected with the combustion chamber (224), and the outlet end is connected with the flue gas waste heat utilization device (104).

9. The device for magnetic separation optimization of iron ore by coal-based coking, reducing and roasting coke according to claim 5, characterized in that the circulating grinding system forms circulating grinding according to the sequence of the pair roller mill (402), the magnetic separator (403), the Raymond mill (404), the screening and extracting machine (405), the elevator (406) and the pair roller mill (402).