Dry grinding closed-circuit production process system for fine iron powder

Abstract

A closed-loop production process system for fine iron powder dry grinding comprises a batching assembly, a ball-milling assembly, a conveying assembly, a sorting assembly, a coarse material circulating assembly, an air flow circulating assembly and a finished product collecting assembly, and the batching assembly mixes iron ore raw materials and coarse materials conveyed by the coarse material circulating assembly and then feeds the mixture into the ball-milling assembly for ball-milling treatment; and then the materials are conveyed into the sorting assembly by the material conveying assembly for sorting treatment. The system is simple in structure and convenient to use, not only can effectively solve the problem of drying raw materials, but also can simplify the technological process, reduce energy consumption, reduce the occupied area of construction and investment cost, and has the remarkable advantages of being energy-saving, environment-friendly, safe, efficient, high in production efficiency and the like.

Description

Technical Field

[0001] The invention relates to the technical field of grinding devices, in particular to a closed-circuit production process system for dry grinding of iron ore concentrate. Background Art

[0002] As the core raw material for pellet production, iron ore concentrate is processed from iron ore through a series of processes. Traditional grinding technologies mainly include wet ball milling and high pressure roller milling, but these technologies have obvious limitations.

[0003] In the wet ball milling process, although the raw ore can be effectively ground, this process consumes a lot of water resources and inevitably produces wastewater. In addition, the ground ore powder needs to go through cumbersome processes such as filtration and drying, which further increases the production cost. On the other hand, although the high-pressure roller mill is known for its high grinding efficiency and low energy consumption, the equipment investment and maintenance costs are relatively high. More importantly, both technologies have problems that cannot be ignored, such as limited drying capacity and large floor space.

[0004] In view of the various shortcomings of traditional processes, how to design and research a new iron ore concentrate grinding production process to simplify the process flow, reduce energy consumption and lower costs is of great significance for promoting the sustainable development of the pellet production industry. Summary of the invention

[0005] The technical purpose of the present invention is to provide a closed-loop production process system for dry grinding of iron ore concentrate with a simple structure and easy use. The system can not only effectively solve the problem of raw material drying, but also simplify the process flow, reduce energy consumption, reduce construction area and investment costs, and has significant advantages such as energy saving and environmental protection, safety and high efficiency, and high production efficiency.

[0006] The present invention solves the above technical problems and adopts the following technical scheme: a closed-loop production process system for dry grinding of iron concentrate, comprising a batching component, a ball mill component, a feeding component, a sorting component, a coarse material circulation component, an airflow circulation component and a finished product collection component. The batching component mixes the iron ore raw material and the coarse material conveyed by the coarse material circulation component and then conveys the mixed mixture into the ball mill component for ball milling. The ball mill component comprises a ball mill and a hot air furnace. A drying bin connected to the hot air furnace and a grinding bin connected to the feeding component are arranged inside the ball mill. The material conveyed by the batching component is dried in the drying bin and ball milled in the grinding bin in turn, and then conveyed by the feeding component to the sorting component for sorting. The sorting component includes a dynamic powder selector, a cyclone and a bag dust collector. The top of the dynamic powder selector is provided with a feed port and a powder outlet, and the bottom is provided with a coarse powder discharge port and a circulating air inlet, wherein the feed port is connected to the conveying end of the feeding component, the circulating air inlet is connected to the exhaust gas discharge port on the ball mill, the powder outlet is connected to the material inlet at the top of the cyclone, and the coarse powder discharge port is connected to the batching component via a coarse material circulation component. The fine powder selected by the dynamic powder selector is carried out from the powder outlet with the airflow, and then is collected by the cyclone and the bag dust collector in turn. The collected fine powder is enriched and stored by the finished product collection component, and the airflow out of the bag dust collector is partially recycled through the airflow circulation component; The airflow circulation component includes a hot air duct, a process fan, a circulation duct, a smoke exhaust duct and a tail gas chimney, wherein the hot air duct is connected between the bag dust collector and the process fan, the circulation duct is connected between the process fan and the circulation air inlet of the dynamic powder classifier, and the circulation duct is provided with an electric four-channel valve for air volume adjustment, the smoke exhaust duct is connected between the process fan and the tail gas chimney, and the smoke exhaust duct is provided with an electric shutter valve for air volume adjustment.

[0007] Furthermore, the batching assembly includes a belt conveyor for conveying iron ore raw materials and a coarse material conveyor for conveying circulating coarse materials, and a punch plate flow meter is also arranged on the coarse material conveyor.

[0008] Furthermore, the high-temperature flue gas generated by the hot blast furnace is transported to the drying chamber of the ball mill via a high-temperature pipeline, and an electric butterfly valve for regulating the temperature of the high-temperature flue gas is also provided on the high-temperature pipeline.

[0009] Furthermore, the electric butterfly valve is provided with a cold air doping port, and the hot air furnace is a cyclone gas hot air furnace with a low-nitrogen burner.

[0010] Furthermore, an automatic ball adding machine for replenishing steel balls to the grinding bin is provided at the end of the grinding bin of the ball mill.

[0011] Furthermore, the air inlet of the drying bin of the ball mill is of a shutter-type structure, and a cylindrical screen is provided at the joint between the grinding bin of the ball mill and the feeding assembly to prevent large particles from entering the feeding assembly.

[0012] Furthermore, the feeding assembly includes a first air chute, a discharge elevator and a second air chute which are arranged in sequence.

[0013] Furthermore, the feed inlet of the dynamic powder selector is arranged at the top thereof, the powder outlet is arranged on one side of the upper part thereof, the lower part of the dynamic powder selector is a funnel-shaped structure, the circulating air inlet is arranged at the bottom of the funnel, and the coarse powder discharge outlet is arranged on one side of the lower part of the funnel. The dynamic powder selector is a variable frequency speed regulating powder selector.

[0014] Furthermore, the coarse material circulation component includes a coarse material elevator connected to the coarse powder discharge port of the dynamic powder selector and a circulating air chute connected to the batching component.

[0015] Furthermore, the finished product collection component includes a finished product air chute and a finished product elevator, and the finished product air chute is respectively connected to the fine powder outlets of the cyclone and the bag dust collector, so that the fine powder collected by the cyclone and the bag dust collector can be transported to the finished product warehouse for storage via the finished product air chute and the finished product elevator in turn.

[0016] Beneficial effects: 1. The closed-loop production process system for dry grinding of iron ore concentrate of the present invention has a simple structure and is easy to use. The ball mill in the system has both efficient drying and grinding functions. The hot air volume and air temperature supplied by the hot air furnace to the ball mill are adjustable, which can adapt to the drying and grinding of raw ores with different moisture contents and has a wide range of applications.

[0017] 2. The closed-loop production process system for dry grinding of iron ore concentrate of the present invention has only one process fan in the entire process system. The process fan serves as a system exhaust fan and also has the function of a circulation fan, thereby reducing the number of equipment, reducing space occupancy, reducing investment costs, and saving system power consumption.

[0018] 3. In the closed-loop production process system for dry grinding of iron ore concentrate of the present invention, the burner of the hot blast furnace adopts a low-nitrogen burner, which effectively reduces the nitrogen oxide content in the tail gas discharged into the atmosphere, and has the function of energy saving and environmental protection.

[0019] 4. The closed-loop production process system for dry grinding of iron ore concentrate of the present invention can add balls to the ball mill evenly on demand through a fully automatic intelligent automatic ball adding machine. The steel balls worn out in the previous unit time can be evenly added to the ball mill without affecting the load of the ball mill. As the steel balls are worn out, a better gradation combination is formed with the steel balls added to the ball mill at different time periods, thereby achieving a sufficient grinding effect on the ore. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the process structure of the present invention; Figure numerals: 1. Belt conveyor, 2. Hot air furnace, 3. Electric butterfly valve, 4. Ball mill, 5. Automatic ball adding machine, 6. First air chute, 7. Discharge elevator, 8. Second air chute, 9. Dynamic powder selector, 10. Cyclone, 11. Bag dust collector, 12. Process fan, 13. Electric shutter valve, 14. Exhaust chimney, 15. Coarse material elevator, 16. Circulating air chute, 17. Punch plate flowmeter, 18. Electric four-channel valve, 19. Finished product air chute, 20. Finished product elevator. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention is clearly and completely described below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0023] like Figure 1 As shown, a closed-loop production process system for dry grinding of iron ore concentrate of the present invention comprises a batching component, a ball mill component, a feeding component, a sorting component, a coarse material circulation component, an air flow circulation component and a finished product collection component.

[0024] The batching component includes a belt conveyor 1 for conveying iron ore raw materials and a coarse material conveyor for conveying circulating coarse materials. The coarse material conveyor is also provided with a punch plate flow meter 17. The batching component mixes the iron ore raw materials and the coarse materials conveyed by the coarse material circulation component and then sends them into the ball mill component for ball milling.

[0025] The ball mill assembly includes a ball mill 4 and a hot blast furnace 2. A drying bin connected to the hot blast furnace 2 and a grinding bin connected to the feeding assembly are arranged inside the ball mill 4. The high-temperature flue gas generated by the hot blast furnace 2 is transported to the drying bin of the ball mill 4 via a high-temperature pipeline. An electric butterfly valve 3 for adjusting the temperature of the high-temperature flue gas is also arranged on the high-temperature pipeline, so that the hot air volume and air temperature at the outlet of the hot blast furnace 2 can be adjusted. A cold air doping port is arranged at the electric butterfly valve 3. The hot blast furnace 2 is a cyclone gas hot blast furnace with a low-nitrogen burner. The high-temperature flue gas generated by the hot blast furnace 2 enters the ball mill 4 through the high-temperature pipeline to provide the ball mill 4 with the heat required for drying. The high-temperature pipeline is provided with an electric butterfly valve 3 for doping cold air, which can flexibly adjust the temperature entering the mill according to the moisture content of the iron ore raw material. The air inlet of the drying bin of the ball mill 4 is of a shutter-type structure, which can increase the ventilation area of ​​the mill, reduce the air inlet resistance of the mill, and enhance the heat exchange capacity of the mill, which can effectively prevent the wind blocking phenomenon at the inlet. The end of the grinding bin of the ball mill 4 is provided with an automatic ball adding machine 5 for replenishing steel balls for the grinding bin. The automatic ball adding machine 5 is a fully automatic intelligent ball adding machine. A cylindrical screen is provided at the joint between the grinding bin of the ball mill 4 and the feeding component to prevent large particles from entering the feeding component. A cylindrical screen is installed at the outlet to prevent broken balls and large particles from entering the finished product. The materials conveyed from the batching component are dried in the drying bin and ball-milled in the grinding bin in turn, and then conveyed by the feeding component to the sorting component for sorting processing; The feeding assembly includes a first air chute 6, a discharge elevator 7 and a second air chute 8 which are arranged in sequence. The first air chute 6 is connected to the outlet at the end of the grinding bin of the ball mill 4. One end of the discharge elevator 7 is connected to the first air chute 6, and the other end is connected to the second air chute 8. The second air chute 8 is connected to the feed port at the top of the dynamic powder selector 9.

[0026] The sorting component includes a dynamic powder classifier 9, a cyclone 10 and a bag dust collector 11. The lower part of the dynamic powder classifier 9 is a funnel-shaped structure. The top of the dynamic powder classifier 9 is provided with a feed port and a powder outlet, and the bottom is provided with a coarse powder discharge port and a circulating air inlet, wherein the feed port is arranged at the top of the dynamic powder classifier 9, and the feed port is connected to the conveying end of the feeding component, the powder outlet is arranged at one side of the upper part of the dynamic powder classifier 9, and the powder outlet is connected to the material inlet at the top of the cyclone 10, the circulating air inlet is arranged at the bottom of the funnel structure of the dynamic powder classifier 9, and the circulating air inlet is connected to the exhaust gas discharge port on the ball mill 4 and the end of the airflow circulation pipeline, the coarse powder discharge port is arranged at one side of the lower part of the funnel structure of the dynamic powder classifier 9, and the coarse powder discharge port is connected to the batching component via the coarse material circulation component, and the dynamic powder classifier 9 is a variable frequency speed regulating powder classifier for adjusting the fineness of the product. The faster the speed of the dynamic powder classifier 9, the higher the fineness of the finished product. The fine powder selected by the dynamic powder selector 9 is carried out from the powder outlet with the air flow, and then collected by the cyclone 10 and the bag dust collector 11 in turn. The collected fine powder is enriched and stored by the finished product collection component, and the air flow out of the bag dust collector is partially recycled by the air flow circulation component.

[0027] The coarse material circulation assembly comprises a coarse material elevator 15 connected to the coarse powder discharge port of the dynamic powder classifier 9 and a circulating air chute 16 connected to the batching assembly.

[0028] The airflow circulation component includes a hot air duct, a process fan 12, a circulation duct, a smoke exhaust duct and a tail gas chimney 14, wherein the hot air duct is connected between the bag dust collector and the process fan 12, the circulation duct is connected between the process fan 12 and the circulation air inlet of the dynamic powder classifier 9, and the circulation duct is provided with an electric four-channel valve 18 for air volume adjustment, the smoke exhaust duct is connected between the process fan 12 and the tail gas chimney 14, and the smoke exhaust duct is provided with an electric shutter valve 13 for air volume adjustment.

[0029] The finished product collection assembly includes a finished product air chute 19 and a finished product elevator 20. The finished product air chute 19 is connected to the fine powder outlets of the cyclone 10 and the bag dust collector 11 respectively, so that the fine powder collected by the cyclone 10 and the bag dust collector 11 can be transported to the finished product warehouse for storage via the finished product air chute 19 and the finished product elevator 20 in turn.

[0030] The present invention discloses a closed-loop production process system for dry grinding of iron ore concentrate, wherein a belt conveyor 1 is used to convey iron ore raw materials, a coarse material conveyor is used to convey recycled coarse materials returned from a dynamic powder concentrator 9, a batching component mixes the iron ore raw materials and the returned materials from the dynamic powder concentrator and sends them together to a ball mill 4, the interior of the ball mill 4 is divided into a drying bin and a grinding bin, the material first enters the drying bin in the ball mill 4 for drying, and then enters the grinding bin for grinding, the ground material is transported in turn through a first air chute 6, a discharging elevator 7 and a second air chute 8, and then is transported to a dynamic powder concentrator 9 for sorting. After being sorted by the dynamic powder classifier 9, the coarse powder is discharged from the coarse powder discharge port after settling at the lower part of the cone of the dynamic powder classifier 9, and is transported to the punching plate flowmeter 17 for measurement through the coarse material elevator 15 and the circulating air chute 16, and then enters the ball mill 4 for further grinding. The fine powder is carried out with the air flow, and the finished fine powder collected by the cyclone 10 and the bag dust collector 11 is sent to the finished product warehouse for storage through the finished product air chute 19 and the finished product elevator 20.

[0031] After passing through the process fan, part of the airflow from the bag dust collector 11 enters the dynamic powder classifier 9 for recycling, and the other part is directly discharged into the atmosphere through the tail gas chimney 14. The circulating air volume can be adjusted by the electric four-channel valve 18 on the circulation pipe and the electric shutter valve 13 on the exhaust pipe. After the ball mill hot air and the circulating air merge, they enter from the bottom of the dynamic powder classifier 9, and the airflow carries the dispersed materials upward into the sorting part for sorting. The dust-containing airflow from the dynamic powder classifier 9 enters the cyclone 10 for pre-collection, which reduces the dust concentration entering the bag dust collector 11 and increases the service life of the dust collector filter bag.

[0032] The closed-loop production process system for dry grinding of iron ore concentrate of the present invention has a simple structure, is easy to install and use, and the high-temperature flue gas generated by the hot blast furnace 2 in the device enters the ball mill 4 through the high-temperature pipeline to provide the ball mill 4 with the heat required for drying. The high-temperature pipeline is provided with an electric butterfly valve 3 for mixing cold air, which can flexibly adjust the temperature entering the mill according to the moisture content of the iron ore raw material. The dynamic powder selector 9 adjusts the fineness of the product through frequency conversion speed regulation. The faster the speed of the dynamic powder selector 9, the higher the fineness of the finished product. An automatic ball adding machine 5 is arranged at the tail of the ball mill 4 to replenish steel balls for the grinding section of the ball mill 4.

[0033] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the entire content of the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still make formal modifications to the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. Any formal modifications, equivalent replacements, etc. made within the scope of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A closed-loop production process system for dry grinding of iron ore concentrate, comprising a batching component, a ball mill component, a feeding component, a sorting component, a coarse material circulation component, an air flow circulation component and a finished product collection component. The batching component mixes the iron ore raw material and the coarse material conveyed by the coarse material circulation component and then sends the mixed mixture into the ball mill component for ball milling, characterized in that: The ball mill assembly comprises a ball mill (4) and a hot air furnace (2). A drying chamber connected to the hot air furnace (2) and a grinding chamber connected to the feeding assembly are arranged inside the ball mill (4). The material conveyed by the batching assembly is dried in the drying chamber and ball-milled in the grinding chamber, and then conveyed by the feeding assembly to the sorting assembly for sorting. The sorting component comprises a dynamic powder selector (9), a cyclone (10) and a bag dust collector (11), wherein the top of the dynamic powder selector (9) is provided with a feed port and a powder outlet, and the bottom is provided with a coarse powder discharge port and a circulating air inlet, wherein the feed port is connected to the conveying end of the feeding component, the circulating air inlet is connected to the exhaust gas discharge port on the ball mill (4), the powder outlet is connected to the material inlet at the top of the cyclone (10), and the coarse powder discharge port is connected to the batching component via the coarse material circulation component. The fine powder sorted by the dynamic powder selector (9) is carried out from the powder outlet along with the airflow, and then collected by the cyclone (10) and the bag dust collector (11) in turn. The collected fine powder is enriched and stored by the finished product collection component, and the airflow out of the bag dust collector is partially recycled by the airflow circulation component. The airflow circulation component comprises a hot air duct, a process fan (12), a circulation duct, a smoke exhaust duct and an exhaust chimney (14), wherein the hot air duct is connected between the bag dust collector and the process fan (12), the circulation duct is connected between the process fan (12) and the circulation air inlet of the dynamic powder selector (9), and an electric four-channel valve (18) for adjusting the air volume is arranged on the circulation duct, and the smoke exhaust duct is connected between the process fan (12) and the exhaust chimney (14), and an electric shutter valve (13) for adjusting the air volume is arranged on the smoke exhaust duct.

2. The closed-circuit production process system for dry grinding of iron ore concentrate according to claim 1, characterized in that: The batching assembly comprises a belt conveyor (1) for conveying iron ore raw materials and a coarse material conveyor for conveying circulating coarse materials, and a punch plate flow meter (17) is also provided on the coarse material conveyor.

3. The closed-circuit production process system for dry grinding of iron ore concentrate according to claim 1, characterized in that: The high-temperature flue gas generated by the hot blast furnace (2) is transported to the drying chamber of the ball mill (4) via a high-temperature pipeline, and an electric butterfly valve (3) for adjusting the temperature of the high-temperature flue gas is also provided on the high-temperature pipeline.

4. The closed-circuit production process system for dry grinding of iron ore concentrate according to claim 3, characterized in that: The electric butterfly valve (3) is provided with a cold air doping port, and the hot air furnace (2) is a cyclone gas hot air furnace with a low-nitrogen burner.

5. The closed-circuit production process system for dry grinding of iron ore concentrate according to claim 1, characterized in that: An automatic ball adding machine (5) for replenishing steel balls for the grinding bin is provided at the end of the grinding bin of the ball mill (4).

6. The closed-circuit production process system for dry grinding of iron ore concentrate according to claim 1, characterized in that: The air inlet of the drying bin of the ball mill (4) is of a shutter-type structure, and a cylindrical screen is provided at the joint between the grinding bin of the ball mill (4) and the feeding assembly to prevent large particles from entering the feeding assembly.

7. The closed-circuit production process system for dry grinding of iron ore concentrate according to claim 1, characterized in that: The material conveying assembly comprises a first air chute (6), a material discharge elevator (7) and a second air chute (8) which are arranged in sequence.

8. The closed-circuit production process system for dry grinding of iron ore concentrate according to claim 1, characterized in that: The feed inlet of the dynamic powder classifier (9) is arranged at the top thereof, the powder outlet is arranged at one side of the upper portion thereof, the lower portion of the dynamic powder classifier (9) is a funnel-shaped structure, the circulating air inlet is arranged at the bottom of the funnel, and the coarse powder discharge outlet is arranged at one side of the lower portion of the funnel. The dynamic powder classifier (9) is a variable frequency speed regulating powder classifier.

9. The closed-circuit production process system for dry grinding of iron ore concentrate according to claim 1 or 8, characterized in that: The coarse material circulation component comprises a coarse material elevator (15) connected to the coarse powder discharge port of the dynamic powder selector (9) and a circulating air chute (16) connected to the batching component.

10. The closed-circuit production process system for dry grinding of iron ore concentrate according to claim 1, characterized in that: The finished product collection assembly comprises a finished product air chute (19) and a finished product elevator (20), wherein the finished product air chute (19) is respectively connected to the fine powder outlets of the cyclone (10) and the bag dust collector (11), so that the fine powder collected by the cyclone (10) and the bag dust collector (11) can be transported to the finished product warehouse for storage via the finished product air chute (19) and the finished product elevator (20) in sequence.

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