A method and system for carbon-free sintering of iron ore powder

Abstract

The present invention belongs to the technical field of iron ore sintering and energy conservation and emission reduction, and specifically relates to a method and system for carbon-free sintering of iron ore powder, the system comprising: a grading batching device for grading raw materials and batching raw materials at each level; a mixing device for mixing the batches at each level obtained by the grading batching device; a belt sintering device for sintering the mixture obtained by the mixing device, the belt sintering device is provided with a distribution device and a bottom material laying device at the feeding end, the distribution device has a side material laying chute; and a crushing device for crushing the sintered material obtained by the belt sintering device. The present invention integrates the drying, preheating, sintering and cooling processes of the sintering mixture into a belt machine, the belt machine adopts burners on both sides of the trolley to spray gas fuel for heating, the drying, preheating and sintering temperatures are easy to control, the hot air of the entire sintering system is recycled, the thermal energy utilization rate is high, and energy is saved.

Description

Technical Field

[0001] The invention belongs to the technical field of iron ore sintering and energy conservation and emission reduction, and in particular relates to a method and system for carbon-free sintering of iron ore powder. Background Art

[0002] At present, the world's iron ore sintering production process is still one of the main ways to make iron ore powder agglomerates, especially in China. Due to the shortage of rich ore powder, the sintering agglomeration process that can adapt to low-grade iron ore powder accounts for a large proportion. At present, the sintering process generally adopts the belt exhaust sintering method. Solid fuel heating and thick material layer sintering are used in the sintering process. The temperature inside the sintering material layer is difficult to accurately control. There are generally high energy consumption, low waste heat utilization rate of sintering exhaust gas, and large pollutant emissions. With the introduction of a series of environmental protection policies, the situation of sintering energy conservation and emission reduction has become very severe. How to achieve energy conservation and emission reduction in iron ore powder sintering technology is an issue of keen concern to iron ore sintering workers. Summary of the invention

[0003] In order to solve the deficiencies of the prior art, the present invention provides a method and system for carbon-free sintering of iron ore powder.

[0004] An iron ore powder carbon-free sintering system, comprising:

[0005] A grading batching device for grading raw materials and batching each grade of raw materials separately;

[0006] A mixing device for mixing the ingredients of each level obtained by the graded batching device;

[0007] A belt sintering device for sintering the mixed material obtained by the mixing device, wherein the belt sintering device is provided with a material distribution device and a bottom material laying device at the feeding end, and the material distribution device has a side material laying chute;

[0008] And a crushing device for crushing the sintered material obtained by the belt sintering device.

[0009] Based on the above technical solution, the raw materials can be graded and mixed before sintering and crushing to obtain sintered ore. The sintering method is to grade and mix the materials to be sintered, and then perform belt sintering and crushing.

[0010] Specifically, the belt sintering device includes:

[0011] The blast drying section, the preheating section, the sintering section, the first cooling section and the second cooling section are sequentially connected, the first cooling section has a first air inlet located at the lower part and a first hot air outlet located at the upper part, the second cooling section has a second air inlet located at the lower part and a second hot air outlet located at the upper part, the sintering section has a third hot air inlet located at the upper part, a third hot air outlet located at the lower rear section and a third air outlet connected to the outside at the lower part of the front section, the preheating section has a fourth hot air inlet and The fourth air outlet at the lower part thereof is connected to the outside, and the blast drying section has a fifth hot air inlet at the lower part thereof and a fifth air outlet at the upper part thereof which is connected to the outside, wherein the second hot air outlet is connected to the fifth hot air inlet through an air supply pipeline; the first hot air outlet is connected to the third hot air inlet and the fourth hot air inlet through an air supply pipeline respectively; the third hot air outlet is connected to the fifth hot air inlet and the fourth hot air inlet through an air supply pipeline respectively, and each air supply pipeline is provided with a fan for air supply;

[0012] A burner device is used to heat the preheating section and the sintering section.

[0013] Based on the above technical solution, the waste heat of the first cooling section, the second cooling section and the sintering section can be fully utilized. The sintering method is to classify and mix the materials to be sintered, and then perform blast drying, preheating, sintering, first cooling and second cooling for belt sintering and crushing.

[0014] The second hot air outlet is connected to the fifth hot air inlet through an air supply pipeline, so that the waste heat of the second cooling section can be recycled; the first hot air outlet is connected to the third hot air inlet and the fourth hot air inlet through an air supply pipeline respectively, so that the waste heat in the first cooling section can be recycled; the third hot air outlet is connected to the fifth hot air inlet and the fourth hot air inlet through an air supply pipeline respectively, so that the waste heat in the sintering section can be recycled.

[0015] Specifically, the grading batching device comprises:

[0016] A screening machine is used to screen the raw materials into oversize with a particle size greater than or equal to 3 mm and undersize with a particle size less than 3 mm;

[0017] A first batching machine and a first mixing and granulating machine are used to batch, mix and granulate the material on the sieve in sequence, and the first mixing and granulating machine and the mixing device are arranged in sequence;

[0018] The second batching machine, the second mixer and the second granulator are used to batch, mix and granulate the material under the sieve in sequence, and the second granulator and the mixing device are arranged in sequence.

[0019] Based on the above technical solution, the oversize material and the undersize material can be separately batched and granulated to obtain a sintered mixed material.

[0020] The present invention also provides an iron ore powder carbon-free sintering method, which uses the iron ore powder carbon-free sintering system provided by the present invention to perform carbon-free sintering, specifically comprising the following steps: using gas fuel as the fuel of the burner device to heat the preheating section and the sintering section.

[0021] Based on the above technical scheme, the mixed iron ore powder is screened and graded, the above-screen and below-screen iron ore powders are respectively mixed with flux in respective proportions, water is added for mixing and granulation, all the mixed materials are mixed, distributed, dried, preheated, sintered, cooled, crushed and screened to obtain the finished sintered ore; a layer of sintered ore is spread on the trolley as a bottom material by using the bottom material system, and then the granulated sintered mixture is evenly distributed on the trolley through the distribution system, and while distributing the sintered mixture, the bottom material chute is used to lay the sintered ore side material between the sintered material and the trolley; through the circulation operation of the trolley, the mixed material on the trolley is dried, preheated, sintered, homogenized and cooled in turn, and then the fired sintered ore is unloaded and crushed at the tail of the machine, and finally transported to the finished product screening system for screening through the belt system.

[0022] Specifically, the raw material is iron ore powder, and the obtained product is sintered ore.

[0023] Specific:

[0024] Adding a mixture of limestone, dolomite and quicklime as a batching material to the first batching machine to adjust the alkalinity range of the oversize material, so that the proportion of the particle size greater than 5 mm in the mixture after granulation by the first granulator is greater than or equal to 50wt%;

[0025] Adding a mixture of limestone, dolomite and quicklime as a batching material to the second batching machine to adjust the alkalinity range of the undersize material, so that the proportion of the part of the mixture with a particle size greater than 3 mm after granulation by the second granulator is greater than or equal to 80wt%;

[0026] Adjusting the ratio of the oversize to the undersize in the mixing device to adjust the alkalinity of the mixture to a range of 0.8 to 1.2;

[0027] Among them, the alkalinity range of the oversize is adjusted to 1.8-2.5, and the alkalinity range of the undersize is adjusted to 0-0.5; or, the alkalinity range of the oversize is adjusted to 0-0.5, and the alkalinity range of the undersize is adjusted to 1.8-2.5.

[0028] Specific:

[0029] The sintering ore bottom material is laid on the trolley of the belt sintering device by using a material distribution device, and the thickness of the material is 200 to 500 mm;

[0030] A bottom material laying device is used to lay sintered ore bottom material on the trolley of the belt sintering device, with a thickness of 30 to 80 mm and a particle size of 8 to 16 mm;

[0031] The material distribution device is used to lay the sintered ore edge material on the trolley of the belt sintering device through the edge material laying chute. The thickness of the sintered ore edge material is 30-60mm and the particle size is 8-16mm.

[0032] Specifically, the time that the sintered mixture spends in the first cooling section is 12 to 15 minutes.

[0033] Specifically, the time that the sintered mixture spends in the second cooling section is 4 to 5 minutes.

[0034] Specifically, the air inlet temperature of the fifth hot air inlet is 200-400° C.; and the time the sintered mixture spends in the blast drying section is 8-10 minutes.

[0035] Specifically, the air inlet temperature of the fourth hot air inlet is 500-1050° C.; the time the sintered mixture spends in the preheating section is 2-5 minutes.

[0036] Specifically, the air inlet temperature of the third hot air inlet is 1200-1350° C.; the time the sintered mixture spends in the sintering section is 12-20 minutes.

[0037] The mixed iron ore powder of the present invention is screened and graded, the iron ore powder on and under the screen is respectively mixed with flux according to respective proportions, water is added for mixing and granulation, no solid fuel is added during the mixing process, gas fuel is used for heating during the sintering process, carbon emission is greatly reduced, the amount of other pollutants generated is reduced, it is beneficial to protect the environment, and reduce environmental protection investment and operation costs.

[0038] The invention divides the mixed iron ore powder into two parts, an upper part and a lower part, through the screening and grading process of the mixed iron ore powder. The iron ore powders in the upper part and the lower part are respectively mixed with flux according to respective proportions, wherein one part of the iron ore powder is mixed to meet the sintered ore basicity range of 1.8-2.5, water is added for mixing and granulation, and the other part of the iron ore powder is mixed to meet the sintered ore basicity range of 0-0.5, water is added for mixing and granulation, all the mixed materials are mixed, the average basicity of all the mixed materials meets the range of 0.8-1.2, the part with higher basicity is solidified by liquid phase to generate liquid core binder, and the part with lower basicity is solidified by solid phase to serve as external binder; the basicity range of the overall sintered ore meets the basicity of self-fluxing sintering, and the reducibility and soft melting property of the sintered ore are good.

[0039] The present invention integrates the sintering mixture drying, preheating, sintering and cooling processes into a belt machine. The belt machine adopts burners on both sides of the trolley to spray gas fuel for heating. The drying, preheating and sintering temperatures are easy to control. The hot air of the entire sintering system is recycled, the thermal energy utilization rate is high, and energy is saved.

[0040] The sintering material layer of the sintering system of the present invention is thin, the sintering speed is fast, the sintering output is large, and the temperature distribution in the material layer is relatively uniform, which is beneficial to improving the strength of the sintered ore.

[0041] The sintered ore cooling of the present invention adopts two-stage cooling on the machine, which reduces the cooling speed of the sintered ore, is beneficial to the cooling and crystallization of the sintered ore, and improves the strength of the sintered ore. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a system diagram of the iron ore powder carbon-free sintering system provided by the present invention.

[0043] Attached Figure 1 The structures represented by the labels are listed below:

[0044] 1. Screening machine, 2. First batching machine, 3. First mixing granulator, 4. Second granulator, 5. Second batching machine, 6. Second mixer, 7. Mixing device, 8. Material distribution device, 9. Bottom material device, 10. Blast drying section, 11. Preheating section, 12. Sintering section, 13. First cooling section, 14. Second cooling section, 15. Crushing device. DETAILED DESCRIPTION

[0045] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0046] It should be noted that when a part or component is considered to be "connected", "located", or "assembled" on another part or component, it may be directly disposed on the other part or component or there may be a central part or component at the same time. The terms "left", "right", "upper", "lower" and similar expressions used herein are for illustrative purposes only.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0048] In a specific embodiment, Figure 1As shown, the iron ore powder carbon-free sintering system includes: a grading batching device for grading raw materials and batching raw materials of each grade respectively; a mixing device 7 for mixing the batches of each grade obtained by the grading batching device; a belt sintering device for sintering the mixed material obtained by the mixing device 7, wherein the belt sintering device is provided with a distribution device 8 and a bottom material laying device 9 at the feeding end, and the distribution device 8 has a side material laying chute; and a crushing device 15 for crushing the sintered material obtained by the belt sintering device. Based on this technical solution, the raw materials can be graded and then sintered and crushed to obtain sintered ore.

[0049] In one embodiment, the belt sintering device includes: a blast drying section 10, a preheating section 11, a sintering section 12, a first cooling section 13 and a second cooling section 14 which are sequentially connected, the first cooling section 13 having a first air inlet located at the lower part thereof and a first hot air outlet located at the upper part thereof, the second cooling section 14 having a second air inlet located at the lower part thereof and a second hot air outlet located at the upper part thereof, the sintering section 12 having a third hot air inlet located at the upper part thereof, a third hot air outlet located at the lower rear section thereof and a third air outlet connected to the outside at the lower part of the front section thereof, the preheating section 11 having The fourth hot air inlet at the upper part and the fourth air outlet at the lower part connected to the outside, the blast drying section 10 has a fifth hot air inlet at the lower part and a fifth air outlet at the upper part connected to the outside; a burner device for heating the preheating section 11 and the sintering section 12; wherein the second hot air outlet is connected to the fifth hot air inlet through an air supply pipeline; the first hot air outlet is connected to the third hot air inlet and the fourth hot air inlet through an air supply pipeline; the third hot air outlet is connected to the fifth hot air inlet and the fourth hot air inlet through an air supply pipeline. Based on this technical solution, the waste heat of the first cooling section, the second cooling section and the sintering section can be fully utilized.

[0050] In one embodiment, the grading batching device includes: a screening machine 1, which is used to screen the raw materials into oversize with a particle size greater than or equal to 3 mm, and undersize with a particle size less than 3 mm; a first batching machine 2, a first mixing granulator 3, and the mixing device 7 are sequentially arranged for batching, mixing and granulating the oversize; a second batching machine 5, a second mixing machine 6, and a second granulator 4 are sequentially arranged for batching, mixing and granulating the undersize, and the second granulator 4 and the mixing device 7 are sequentially arranged. Based on this technical solution, the oversize and undersize can be batched and granulated separately to obtain a sintered mixture. The raw material feeding device feeds the screening machine 1.

[0051] Example 1

[0052] The mixed iron ore powder is screened and graded, the above-screened and below-screened iron ore powders are respectively mixed with the flux for batching in respective proportions, and water is added for mixing and granulation respectively. All the mixed materials are mixed, distributed, dried, preheated, sintered, cooled, crushed and screened to obtain the finished sintered ore; a layer of sintered ore is spread on the trolley of the belt sintering device as a bottom material by using a bottom material laying device, and then the granulated sintered mixture is evenly distributed on the trolley through the spreading device, and while the sintered mixture is distributed, the sintered ore side material is laid between the sintered material and the trolley by using the side material laying chute; through the circulation operation of the trolley, the mixed material on the trolley is dried, preheated, sintered, homogenized and cooled in turn, and then the fired sintered ore is unloaded and crushed at the tail of the machine, and finally transported to the finished product screening system through the belt system for screening.

[0053] The screening and grading process of the mixed iron ore powder divides the mixed iron ore powder into two parts, the above-sieve part and the below-sieve part. The particle size of the above-sieve part is greater than 3mm, and the particle size of the below-sieve part is less than 3mm. The iron ore powders in the above-sieve and below-sieve parts are respectively mixed with flux in respective proportions, wherein one part of the iron ore powder is mixed to meet the sintered ore alkalinity range of 1.8-2.5, and water is added for mixing and granulation, and the other part of the iron ore powder is mixed to meet the sintered ore alkalinity range of 0-0.5, and water is added for mixing and granulation. All the mixtures are mixed, and the average alkalinity of all the mixtures meets about 1.0. The mixing and granulation equipment for the mixed iron ore powder on the sieve and the flux is a drum mixer, and the granulation effect meets the requirement that the part with a particle size greater than 5mm accounts for more than 50%, the mixing equipment for the mixed iron ore powder under the sieve and the flux is a vertical mixer, the granulation equipment is a disc pelletizer, and the granulation effect meets the requirement that the part with a particle size greater than 3mm accounts for more than 80%.

[0054] The thickness of the sintered ore bottom material is 60mm, the particle size is 8-16mm, the total height of the material on the trolley is 300mm, the thickness of the sintered ore side material is 30mm, and the particle size of the sintered ore side material is 8-16mm.

[0055] The cooling process is blast cooling, and the cooling process is divided into cooling stage one and cooling stage two. The cooling medium for primary cooling is natural air, and the airflow direction passes through the material layer from bottom to top, and the cooling time is 12 minutes. The cooling medium for secondary cooling is natural air, and the airflow direction passes through the material layer from bottom to top, and the cooling time is 4 minutes.

[0056] The drying process is blast drying. The hot air for blast drying comes from the medium-temperature flue gas in the second cooling stage, the second half of sintering and the equalizing stage. The temperature is about 300°C. The airflow passes through the material layer from bottom to top. The drying time is 8 minutes, thereby recycling the waste heat in the second cooling stage and the sintering stage.

[0057] The preheating process is exhaust preheating. The preheating hot air comes from the burner system, the medium and high temperature flue gas in the second half of sintering and the high temperature flue gas in the cooling section. The preheating temperature is about 800℃ and the preheating time is 3 minutes, thereby recycling the waste heat in the cooling section and the sintering section.

[0058] The sintering process is exhaust sintering. The sintering hot air comes from the burner system and the high-temperature flue gas of the cooling section. The sintering temperature is about 1300℃ and the sintering time is 14 minutes, thereby recycling the waste heat of the cooling section.

[0059] The finished sintered ore is obtained with a finished product rate of 82% and a drum rate of 75%. Compared with traditional belt-type exhaust sintering, the sintering process of the present invention reduces energy consumption by 25%, carbon dioxide emissions by 75%, nitrogen oxide emissions by 7%, sulfur dioxide emissions by 60%, and dioxin and fluoride emissions by 90%.

[0060] Example 2

[0061] The mixed iron ore powder is screened and graded, the above-screen and below-screen iron ore powders are respectively mixed with flux in respective proportions, water is added for mixing and granulation, all the mixed materials are mixed, distributed, dried, preheated, sintered, cooled, crushed and screened to obtain the finished sintered ore; a layer of sintered ore is spread on the trolley as a base material by using the base material system, and then the granulated sintered mixture is evenly distributed on the trolley through the distribution system, and while distributing the sintered mixture, the sintered ore side material is spread between the sintered material and the trolley by using the base material chute; through the circulation operation of the trolley, the mixed material on the trolley is dried, preheated, sintered, homogenized and cooled in turn, and then the fired sintered ore is unloaded and crushed at the tail of the machine, and finally transported to the finished product screening system for screening through the belt system.

[0062] The screening and grading process of the mixed iron ore powder divides the mixed iron ore powder into two parts, the upper part and the lower part. The particle size of the upper part is greater than 3mm, and the particle size of the lower part is less than 3mm. The iron ore powders in the upper part and the lower part are respectively mixed with the flux according to their respective proportions, wherein one part of the iron ore powder is mixed to meet the sintering ore basicity range of 1.8 to 2.5, and water is added for mixing and granulation, and the other part of the iron ore powder is mixed to meet the sintering ore basicity range of 0 to 0.5, and water is added for mixing and granulation. All the mixed materials are mixed, and the average basicity of all the mixed materials meets 1.0. The mixing and granulation equipment for the mixed iron ore powder on the sieve and the flux is a drum mixer, and the granulation effect meets the proportion of the part with a particle size greater than 5mm exceeding 50%, the mixing equipment for the mixed iron ore powder under the sieve and the flux is a vertical mixer, and the granulation equipment is a disc pelletizer, and the granulation effect meets the proportion of the part with a particle size greater than 3mm exceeding 80%;

[0063] The thickness of the sintered ore bottom material is 50mm, the particle size is 8-16mm, the total height of the material on the trolley is 350mm, the thickness of the sintered ore side material is 40mm, and the particle size is 8-16mm;

[0064] Preferably, the cooling process is blast cooling, and the cooling process is divided into cooling stage one and cooling stage two. The cooling medium for the first cooling is natural air, and the airflow direction passes through the material layer from bottom to top, and the cooling time is 14 minutes. The cooling medium for the second cooling is natural air, and the airflow direction passes through the material layer from bottom to top, and the cooling time is 5 minutes.

[0065] The drying process is blast drying. The hot air for blast drying comes from the medium-temperature flue gas in the second cooling stage, the second half of sintering and the equalizing stage. The temperature is about 300°C. The airflow passes through the material layer from bottom to top. The drying time is 10 minutes, thereby recycling the waste heat in the second cooling stage and the sintering stage.

[0066] The preheating process is exhaust preheating. The preheating hot air comes from the burner system, the medium and high temperature flue gas in the second half of roasting and the high temperature flue gas in the cooling section. The preheating temperature is about 750℃ and the preheating time is 5 minutes, thereby recycling the waste heat in the cooling section and the sintering section.

[0067] The sintering process is exhaust sintering. The sintering hot air comes from the burner system and the high-temperature flue gas of the cooling section. The sintering temperature is about 1350℃ and the sintering time is 16 minutes, thereby recycling the waste heat of the cooling section.

[0068] The finished sintered ore is obtained with a finished product rate of 87% and a drum rate of 78%. Compared with traditional belt-type exhaust sintering, the sintering process of the present invention reduces energy consumption by 20%, carbon dioxide emissions by 72%, nitrogen oxide emissions by 5%, sulfur dioxide emissions by 63%, and dioxin and fluoride emissions by 93%.

[0069] Example 3

[0070] The mixed iron ore powder is screened and graded, the above-screened and below-screened iron ore powders are respectively mixed with the flux for batching in respective proportions, and water is added for mixing and granulation respectively. All the mixed materials are mixed, distributed, dried, preheated, sintered, cooled, crushed and screened to obtain the finished sintered ore; a layer of sintered ore is spread on the trolley of the belt sintering device as a bottom material by using a bottom material laying device, and then the granulated sintered mixture is evenly distributed on the trolley through the spreading device, and while the sintered mixture is distributed, the sintered ore side material is laid between the sintered material and the trolley by using the side material laying chute; through the circulation operation of the trolley, the mixed material on the trolley is dried, preheated, sintered, homogenized and cooled in turn, and then the fired sintered ore is unloaded and crushed at the tail of the machine, and finally transported to the finished product screening system through the belt system for screening.

[0071] The screening and grading process of the mixed iron ore powder divides the mixed iron ore powder into two parts, the above-sieve part and the below-sieve part. The particle size of the above-sieve part is greater than 3mm, and the particle size of the below-sieve part is less than 3mm. The iron ore powders in the above-sieve part and the below-sieve part are respectively mixed with flux in respective proportions, wherein one part of the iron ore powder is mixed to meet the sintered ore alkalinity range of 1.8-2.5, and water is added for mixing and granulating, and the other part of the iron ore powder is mixed to meet the sintered ore alkalinity range of 0-0.5, and water is added for mixing and granulating. All the mixtures are mixed, and the average alkalinity of all the mixtures meets 1.0. The mixing and granulating equipment for the mixed iron ore powder on the sieve and the flux is a drum mixer, and the granulation effect meets the requirement that the part with a particle size greater than 5mm accounts for more than 50%, the mixing equipment for the mixed iron ore powder under the sieve and the flux is a vertical mixer, the granulating equipment is a disc pelletizing machine, and the granulation effect meets the requirement that the part with a particle size greater than 3mm accounts for more than 80%.

[0072] The thickness of the sintered ore bottom material is 60mm, the particle size is 8-16mm, the total height of the material on the trolley is 400mm, the thickness of the sintered ore side material is 30mm, and the particle size is 8-16mm.

[0073] The cooling process is blast cooling, and the cooling process is divided into cooling stage one and cooling stage two. The cooling medium for primary cooling is natural air, and the airflow direction passes through the material layer from bottom to top, and the cooling time is 12 minutes. The cooling medium for secondary cooling is natural air, and the airflow direction passes through the material layer from bottom to top, and the cooling time is 4 minutes.

[0074] The drying process is blast drying. The hot air for blast drying comes from the medium-temperature flue gas in the second cooling stage, the second half of sintering and the equalizing stage. The temperature is about 300°C. The airflow passes through the material layer from bottom to top. The drying time is 8 minutes, thereby recycling the waste heat in the second cooling stage and the sintering stage.

[0075] The preheating process is exhaust preheating. The preheating hot air comes from the burner system, the medium and high temperature flue gas in the second half of roasting and the high temperature flue gas in the cooling section. The preheating temperature is about 800℃ and the preheating time is 3 minutes, thereby recycling the waste heat in the cooling section and the sintering section.

[0076] The sintering process is exhaust sintering. The sintering hot air comes from the burner system and the high-temperature flue gas of the cooling section. The sintering temperature is about 1300℃ and the sintering time is 14 minutes, thereby recycling the waste heat of the cooling section.

[0077] The finished sintered ore is obtained with a finished product rate of 84% and a drum rate of 76%. Compared with traditional belt-type exhaust sintering, the sintering process of the present invention reduces energy consumption by 23%, carbon dioxide emissions by 75%, nitrogen oxide emissions by 8%, sulfur dioxide emissions by 58%, and dioxin and fluoride emissions by 92%.

[0078] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the drawings and above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A method for carbon-free sintering of iron ore powder, characterized in that: Adopt iron ore powder carbon-free sintering system for carbon-free sintering; The iron ore powder carbon-free sintering system comprises: A grading batching device for grading raw materials and batching each grade of raw materials separately; A mixing device (7) for mixing the ingredients of each level obtained by the graded batching device; a belt sintering device for sintering the mixed material obtained by the mixing device (7); and a crushing device (15) for crushing the sintered material obtained by the belt sintering device; The belt sintering device comprises: A blast drying section (10), a preheating section (11), a sintering section (12), a first cooling section (13) and a second cooling section (14) are sequentially connected, the first cooling section (13) having a first air inlet located at a lower portion thereof and a first hot air outlet located at an upper portion thereof, the second cooling section (14) having a second air inlet located at a lower portion thereof and a second hot air outlet located at an upper portion thereof, the sintering section (12) having a third hot air inlet located at an upper portion thereof, a third hot air outlet located at a lower rear portion thereof and a third air outlet located at a lower portion thereof and connected to the outside, The preheating section (11) has a fourth hot air inlet located at the upper part thereof and a fourth air outlet located at the lower part thereof and connected to the outside, and the blast drying section (10) has a fifth hot air inlet located at the lower part thereof and a fifth air outlet located at the upper part thereof and connected to the outside, wherein the second hot air outlet is connected to the fifth hot air inlet via an air supply pipeline; the first hot air outlet is connected to the third hot air inlet and the fourth hot air inlet via an air supply pipeline respectively; and the third hot air outlet is connected to the fifth hot air inlet and the fourth hot air inlet via an air supply pipeline respectively; and a burner device for heating the preheating section (11) and the sintering section (12); The belt sintering device is provided with a material distribution device (8) and a bottom material laying device (9) at the feeding end, and the material distribution device (8) has a side material laying chute; The grading batching device comprises: A screening machine (1) for screening the raw material into an oversize material having a particle size greater than or equal to 3 mm and an undersize material having a particle size less than 3 mm; a first batching machine (2) and a first mixing granulator (3) for batching, mixing and granulating the material on the sieve in sequence, wherein the first mixing granulator (3) and the mixing device (7) are arranged in sequence along the material flow direction; a second batching machine (5), a second mixer (6) and a second granulator (4) for batching, mixing and granulating the undersize material in sequence, wherein the second granulator (4) and the mixing device (7) are arranged in sequence along the material flow direction; The iron ore powder carbon-free sintering method specifically comprises the following steps: Using gas fuel as fuel for a burner device to heat the preheating section (11) and the sintering section (12); A mixture of limestone, dolomite and quicklime is added to the first batching machine (2) as a batching material to adjust the alkalinity range of the oversize material, and after granulation by the first mixing granulator (3), the proportion of particles larger than 5 mm in the mixture is greater than or equal to 50 wt%; A mixture of limestone, dolomite and quicklime is added to the second batching machine (5) as a batching material to adjust the alkalinity range of the undersize material, and after granulation by the second granulator (4), the proportion of particles larger than 3 mm in the mixture is greater than or equal to 80 wt %; Adjusting the ratio of the oversize material to the undersize material in the mixing device (7) to adjust the alkalinity of the mixture to a range of 0.8 to 1.2; Among them, the alkalinity range of the oversize is adjusted to 1.8-2.5, and the alkalinity range of the undersize is adjusted to 0-0.5; or, the alkalinity range of the oversize is adjusted to 0-0.5, and the alkalinity range of the undersize is adjusted to 1.8-2.

5.

2. The method for carbon-free sintering of iron ore powder according to claim 1, characterized in that: Using a material distribution device (8) to spread the sintering mixture on the trolley of the belt sintering device, the thickness of which is 200 to 500 mm; A bottom material laying device (9) is used to lay a sintered ore bottom material on a trolley of a belt sintering device, wherein the thickness of the sintered ore bottom material is 30 to 80 mm and the particle size is 8 to 16 mm; A material distribution device (8) is used to lay sintered ore edge material on the trolley of the belt sintering device through the edge material laying chute, and the thickness of the sintered ore edge material is 30 to 60 mm and the particle size is 8 to 16 mm.

3. The method for carbon-free sintering of iron ore powder according to claim 1, characterized in that: The time that the sintered mixture spends in the first cooling section (13) is 12 to 15 minutes; The time that the sintered mixture spends in the second cooling section (14) is 4 to 5 minutes.

4. The method for carbon-free sintering of iron ore powder according to claim 1, characterized in that: The air inlet temperature of the fifth hot air inlet is 200 to 400° C.; the time the sintered mixed material spends in the blast drying section (10) is 8 to 10 minutes.

5. The method for carbon-free sintering of iron ore powder according to claim 1, characterized in that: The air inlet temperature of the fourth hot air inlet is 500-1050° C.; the time the sintered mixture spends in the preheating section (11) is 2-5 minutes.

6. The method for carbon-free sintering of iron ore powder according to claim 1, characterized in that: The air inlet temperature of the third hot air inlet is 1200-1350° C.; and the time the sintered mixed material spends in the sintering section (12) is 12-20 minutes.

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