Multi-vent vertical mill device and working method thereof

Abstract

The application discloses a multi-vent opening vertical mill device and a working method thereof, and belongs to the technical field of vertical mill devices. The vertical mill device comprises a mill shell, a powder classifier is arranged in the mill shell, a central cone is arranged at the bottom of the powder classifier, a grinding disc is arranged below the central cone, a grinding roller is arranged on the grinding disc, a tuyere ring is arranged below the edge of the grinding disc, and a ventilation ring structure is arranged above the horizontal plane where the edge of the grinding disc is located. The ventilation ring structure is used for supplementing air volume to the air-powder mixing area between the central cone and the mill shell or for sucking and discharging the powdery material in the air-powder mixing area to the outside of the vertical mill device. The vertical mill device can effectively reduce the outer diameter of the mill shell under the condition that the air volume of the mill and the air speed of the tuyere ring are met, and can also make part of the coarse powder generated in the vertical mill to be recycled or purified before being returned to the grinding disc, so that the grinding work is reduced, and the grinding efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a vertical mill device. BACKGROUND

[0002] When the vertical mill works, the millstone rotates under the drive of the main vertical transmission system, and the mill roller applies the rolling pressure to the millstone through the hydraulic system to produce the fine crushing and grinding function on the materials (slag, steel slag, iron ore, etc.). The hot air enters from the lower air inlet and is sprayed out through the tuyere ring below the edge of the millstone, carries the superfine powder of the ground slag, steel slag, iron ore, etc. upwards, passes through the air-powder mixing area between the center cone and the mill shell, and exchanges heat during the conveying process to dry the moisture in the superfine powder. The qualified particle size of the superfine powder is selected by the static and dynamic powder classifier at the upper part, and the unqualified coarse powder is returned to the millstone for regrinding.

[0003] For the air volume of the mill, including the air volume for material drying and the air volume required for the material in the mill to complete the pneumatic conveying, the larger value of the two air volumes is the air volume of the mill. In order to control the mill discharge amount, the wind speed at the tuyere ring of the mill should be greater than the critical wind speed that makes the discharge slag suspended. The wind speed is determined by the tuyere ring area, and in the case of a certain tuyere ring angle, the critical wind speed determines the minimum outer diameter of the tuyere ring. Therefore, the larger the air volume of the mill is, the larger the outer diameter of the mill tuyere ring is, the larger the outer diameter of the mill shell is, and the larger the manufacturing cost and the space occupied by the shell are.

[0004] The vertical mill is essentially a superfine crushing device, but the traditional vertical mill device can only pass the qualified particle size of the material product through the powder classifier on the vertical mill and leave the vertical mill. The material that does not meet the qualified particle size (these medium particle size powders, hereinafter referred to as "coarse powder") is separated by the powder classifier rotor and returned to the millstone for further grinding until the material product that meets the qualified particle size can leave the vertical mill, and so on. During the internal circulation process of the material in the vertical mill, the particle size gradually becomes finer.

[0005] This large amount of particle size from large to small process makes the energy consumption of the vertical mill running larger. In order to save the energy consumption of the crushed material, we hope that under the premise of meeting the function of the vertical mill, the coarse powder generated inside the vertical mill can be recycled or purified before returning to the millstone. SUMMARY

[0006] The purpose of the present application is to provide a vertical mill device with multiple air vents and a working method thereof, which can avoid the problem of large space occupied by the shell due to the increase of the air volume, and also enable the coarse powder generated inside the vertical mill to be transported to the outside of the vertical mill for recycling or purification before returning to the millstone.

[0007] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0008] A multi-vent vertical mill device, comprising a mill shell, a classifier arranged inside the mill shell, a central cone arranged at the bottom of the classifier, a grinding disc arranged below the central cone, a grinding roller arranged on the grinding disc, a tuyere ring arranged below the edge of the grinding disc, a vent ring structure arranged above the horizontal plane where the edge of the grinding disc is located, the vent ring structure is used to supplement the air volume to the air-powder mixing area between the central cone and the mill shell, or to suck and discharge the powdery material in the air-powder mixing area to the outside of the vertical mill device.

[0009] Further, the vent ring structure is below the highest position of the grinding roller.

[0010] Further, the vent ring structure comprises a ring-shaped vent cavity, a mill internal vent interface, the ring-shaped vent cavity is arranged inside the mill shell, the ring-shaped vent cavity is connected with the mill internal vent interface outside, the mill internal vent interface is arranged on the mill shell, and multiple vents are arranged inside the ring-shaped vent cavity.

[0011] Further, the vent ring structure comprises a ring-shaped vent cavity, a mill internal vent interface, a mill internal vent pipe, the ring-shaped vent cavity is arranged outside the central cone, the upper part of the ring-shaped vent cavity outside is connected with the mill internal vent interface through the mill internal vent pipe, the mill internal vent interface is arranged on the mill shell, and multiple vents are arranged at the lower part of the ring-shaped vent cavity outside.

[0012] Further, the mill internal vent interface is connected with the feeding port of the magnetic separator through the induced draft fan, the discharging port of the magnetic separator is connected with the mill return port, and the mill return port is arranged on the mill shell.

[0013] Further, the vent is provided with a guide plate for guiding the air flow of the vent, and the guide plate is deflected along the rotation direction of the grinding disc.

[0014] Further, the included angle α between the guide plate and the symmetry axis of the ring-shaped vent cavity is 10-80°.

[0015] The working method of the vertical mill device is as follows: the air volume required for pneumatic conveying of the completed material is introduced into the air-powder mixing area in the mill shell through the tuyere ring, when the air volume introduced by the tuyere ring cannot meet the requirement of material drying, the supplementary air volume is introduced into the air-powder mixing area between the central cone and the mill shell through the vent ring structure, when the air volume introduced by the tuyere ring can meet the requirement of material drying, the powdery material in the air-powder mixing area is sucked and discharged to the outside of the vertical mill device through the vent ring structure, the separated magnetic and non-magnetic materials are separated by the magnetic separation equipment, and the non-magnetic materials or non-magnetic materials at the particle size scale of the part of the material are removed according to the requirement, and the remaining material is returned to the vertical mill device for further grinding.

[0016] Further, when grinding magnetic iron ore, the non-magnetic materials are removed by the magnetic separation equipment to improve the quality of the magnetic iron ore powder, and when grinding steel slag, the magnetic materials are removed by the magnetic separation equipment to improve the activity of the steel slag powder.

[0017] Beneficial effects: the vertical mill device can effectively reduce the outer diameter of the mill shell by adding the ventilation ring structure above the tuyere ring, can also suck and exhaust the powdery material in the wind-powder mixing area outward, so that part of the coarse powder generated in the vertical mill is transported to the outside of the vertical mill before returning to the grinding table, reducing unnecessary grinding work, thereby improving the grinding efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a vertical mill device structure schematic diagram of the embodiment one of the present application;

[0019] Figure 2 It is a ventilation ring structure installation schematic diagram of the embodiment one of the present application;

[0020] Figure 3 It is a ventilation ring structure structure schematic diagram of the embodiment one of the present application;

[0021] Figure 4 It is a ring-shaped ventilation cavity inside development schematic diagram of the embodiment one of the present application;

[0022] Figure 5 It is a vertical mill device structure schematic diagram of the embodiment two of the present application;

[0023] Figure 6 It is a ventilation ring structure installation schematic diagram of the embodiment two of the present application;

[0024] Figure 7 It is a ventilation ring structure structure schematic diagram of the embodiment two of the present application;

[0025] Figure 8 It is a ring-shaped ventilation cavity inside development schematic diagram of the embodiment two of the present application;

[0026] In the figure: 1 - powder selector; 2 - mill shell; 3 - mill return port; 4 - center cone; 5 - wind-powder mixing area; 6 - grinding roller; 7 - tuyere ring; 8 - grinding table; 9 - mill discharge port, 10 - mill air inlet; 11 - ventilation ring structure; 12 - mill feed port; 13 - mill air outlet; 14 - ring-shaped ventilation cavity; 15 - mill internal ventilation interface; 16 - guide plate; 17 - mill internal ventilation pipe; 18 - ventilation port; 19 - rocker arm; 20 - hydraulic cylinder. DETAILED DESCRIPTION

[0027] The present application will be further explained below in combination with the drawings.

[0028] As Figure 1 and 5As shown, a vertical mill device with multiple ventilation openings according to the present invention includes a mill housing 2, a classifier 1 is installed inside the mill housing 2, the air outlet of the classifier 1 is connected to the mill air outlet 13 installed on the mill housing 2, a central cone 4 is installed at the bottom of the classifier 1, a grinding disc 8 is installed below the central cone 4, a grinding roller 6 is installed on the grinding disc 8, an air nozzle ring 7 is installed below the edge of the grinding disc 8, the lower part of the air nozzle ring 7 is connected to the mill air inlet 10 installed on the mill housing 2, and a mill slag discharge port 9 is installed below the air nozzle ring 7.

[0029] When the vertical mill is working, the material is fed onto the grinding disc 6 through the mill feed inlet 12. The grinding roller 6 presses the grinding disc 8 through the rocker arm 19 and hydraulic cylinder 20. The grinding roller 6 crushes the material on the grinding disc 8 into powder. Hot air is delivered to the air nozzle ring 7 through the mill air inlet 10. The smaller particles of the powder overflowing from the edge of the grinding disc 8 are conveyed upward through the air-powder mixing zone 5 between the central cone 4 and the mill housing 2 by the high-temperature airflow from the air nozzle ring 7 and sent to the classifier 1. The classifier 1 separates the coarse powder in the powder that does not meet the fineness requirements of the finished product. The separated coarse powder falls back to the grinding disc 8 through the central discharge channel of the central cone 4 and is then re-grinded by the grinding roller 6. The larger particles in the material cannot be lifted by the high-temperature airflow and fall downward to the mill slag discharge port 9. The fine powder in the powder that meets the fineness requirements of the finished product is discharged through the mill air outlet 13.

[0030] The present invention provides a ventilation ring structure 11 above the horizontal plane where the edge of the grinding disc 8 is located. Preferably, the ventilation ring structure 11 is located below the highest position of the grinding roller. The ventilation ring structure 11 supplements the air volume into the air-powder mixing zone 5 between the central cone 4 and the mill housing 2, or sucks the powdery material in the air-powder mixing zone 5 to the outside of the vertical mill device.

[0031] like Figures 1 to 4 As shown, in Embodiment 1 of the present invention, the ventilation ring structure 11 includes an annular ventilation cavity 14 and a mill internal ventilation interface 15. The annular ventilation cavity 14 is disposed inside the mill housing 2, and the annular ventilation cavity 14 is connected to the mill internal ventilation interface 15 on the outside. The mill internal ventilation interface 15 is disposed in the mill housing 2, and a plurality of ventilation openings 18 are provided at intervals inside the annular ventilation cavity 14.

[0032] External air enters the annular ventilation chamber 14 through the internal ventilation interface 15, and then is blown towards the center of the grinding disc 8 through multiple ventilation holes 18 inside the annular ventilation chamber 14. This vertical mill is suitable for applications where the moisture content of the material to be ground varies greatly. The ventilation ring structure 11 can supplement the air volume. When the moisture content is low, a smaller hot air flow is required, and only the air nozzle ring 7 needs to provide hot air; the ventilation ring structure 11 can be inactive. When the moisture content is high and a larger hot air flow is required, the air volume is supplemented through the annular ventilation chamber 14 to meet the drying needs of the material. This reduces the outer diameter of the mill's grinding area shell and lowers investment costs.

[0033] As shown in Figure 3 The air vents 18 are provided with guide plates 16 for guiding the air flow of the air vents 18. In this embodiment, the grinding disc rotates clockwise, and correspondingly, all the guide plates are deflected along the rotation direction of the grinding disc, and the included angle a between the guide plate and the symmetry axis of the annular air chamber is 10-80°. Since the guide plates are deflected along the rotation direction of the grinding disc, the air flow can have as much contact area with the material as possible. Through the combined action of the air flow ejected from the air vents 18 and the high-temperature air flow sent out by the tuyere ring 7, the material can be lifted upward more quickly.

[0034] As shown in Figures 5 to 8 In the second embodiment of the present application, the air ring structure 11 includes an annular air chamber 14, an internal grinding air interface 15, and an internal grinding air pipe 17. The annular air chamber 14 is arranged outside the central cone 4. The upper part outside the annular air chamber 14 is connected to the internal grinding air interface 15 through the internal grinding air pipe 17. The internal grinding air interface 15 is arranged in the mill shell 2. The lower part outside the annular air chamber 14 is arranged with multiple air vents 18. The internal grinding air interface 15 is connected to the feed inlet of the magnetic separator (not shown in the figure) through the induced draft fan, and the discharge outlet of the magnetic separator is connected to the mill return port 3 arranged in the mill shell 2.

[0035] As shown in Figure 7 The air vents 18 are provided with guide plates 16 for guiding the air flow of the air vents 18. In this embodiment, the grinding disc rotates clockwise, and correspondingly, all the guide plates are deflected along the rotation direction of the grinding disc, and the included angle a between the guide plate and the symmetry axis of the annular air chamber is 10-80°.

[0036] The external air enters the annular air chamber 14 through the internal grinding air interface 15 and the internal grinding air pipe 17, and is blown towards the edge of the grinding disc 8 through the multiple air vents 18 outside the annular air chamber 14. The vertical mill device is suitable for grinding materials with large changes in moisture. When the moisture is small, a small amount of hot air flow is required, at which time only the tuyere ring 7 provides hot air, and the air ring structure 11 can not work. When the moisture is large, the hot air flow needs to be increased, and the annular air chamber 14 is used to supplement the air volume to meet the drying needs of the material. Thus, the outer diameter of the grinding area shell of the mill is reduced, and the investment is reduced.

[0037] At the same time, in the second embodiment of the present application, the hot air is blown from the center of the grinding disc 8 to the edge direction, which can increase the conveying capacity of the material above the grinding disc to the powder concentrator. In the traditional mill, the hot air is blown from the air nozzle ring arranged around the grinding disc, and the air flow above the center of the grinding disc is very weak. The material falling back to the grinding disc from the air-powder mixing area 5 will carry some qualified ultra-fine powder due to the factors such as circulation, and these qualified ultra-fine powder will be overground on the grinding disc, increasing the ungrindable material. In the second embodiment, the air blown from the center of the grinding disc 8 to the edge direction will enhance the conveying capacity of this area to the powder concentrator, reduce the proportion of qualified ultra-fine powder carried by the material falling back to the grinding disc from the air-powder mixing area 5, reduce unnecessary work, and improve the grinding efficiency.

[0038] As shown in Figure 5 After the material is crushed into powder by the grinding roller 6, it falls from the edge of the grinding disc 8, and under the action of the air flow blown by the air nozzle ring 7 below the edge of the grinding disc 8, the part with larger particle size in the powdered material cannot be carried by the hot air and falls to the mill discharge port 9. This part is the coarsest powder. For the part with smaller particle size, it will be carried by the air flow and then pass through the air-powder mixing area 5 between the center cone 4 and the mill shell 2. In this process, a part of the material still cannot reach the powder concentrator, which is the second coarsest powder. This part of the material will move along an arc trajectory and finally fall onto the surface of the grinding disc 8 or be blocked by the center cone 4 during upward movement and then fall onto the surface of the grinding disc 8. The powdered material that can enter the powder concentrator 1 is separated by the rotor of the powder concentrator 1 to obtain qualified ultra-fine powder with qualified particle size, and the unqualified coarse powder is returned to the grinding disc 8 through the central downward channel of the center cone 2 for regrinding. According to the particle size of the material, the particle size of the coarsest powder, the second coarsest powder, and the coarse powder decreases in turn.

[0039] For the above-mentioned second coarsest powder part, it can be sucked and discharged outward through the ventilation ring structure 11. The sucked and discharged material is separated by a magnetic separator into magnetic and non-magnetic materials in time, and the non-magnetic material or non-magnetic material under the particle size of this part of the material is removed as needed, reducing unnecessary grinding work, thereby improving the grinding efficiency. The remaining material is returned to the vertical mill device for continuous grinding, achieving the purpose of energy-saving vertical mill energy consumption.

[0040] The working method of the vertical mill device of the application, the air volume required for completing material pneumatic conveying is passed into the air-powder mixing area in the mill shell through the tuyere ring, when the air volume passed into by the tuyere ring cannot meet the requirement of material drying, the supplementary air volume is passed into the air-powder mixing area between the central cone and the mill shell through the air passing ring structure, the supplementary air volume is equivalent to the difference between the air volume required for meeting the requirement of material drying and the air volume required for completing material pneumatic conveying, when the air volume passed into by the tuyere ring can meet the requirement of material drying, the powdery material in the air-powder mixing area is sucked and discharged to the vertical mill device through the air passing ring structure, the powdery material sucked and discharged is separated into magnetic and non-magnetic materials through the magnetic separation equipment, the non-magnetic material or non-magnetic material at the particle size scale of the part of the material is removed according to the requirement, and the rest of the material is returned to the vertical mill device for continuous grinding. When grinding magnetic iron ore, the non-magnetic material such as gangue is removed through the magnetic separation equipment to improve the quality of the magnetic iron ore powder, and when grinding steel slag, the magnetic material such as RO phase is removed through the magnetic separation equipment to improve the activity of the steel slag powder.

[0041] The above only describes the preferred embodiments of the application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the application, and these improvements and refinements should also be considered as the protection scope of the application.

Claims

1. A multi-vent vertical mill device, comprising a mill shell, a classifier is arranged inside the mill shell, a central cone is arranged at the bottom of the classifier, a grinding disc is arranged below the central cone, a grinding roller is arranged on the grinding disc, and a tuyere ring is arranged below the edge of the grinding disc, characterized in that: The ventilation ring structure is arranged above the horizontal plane where the edge of the grinding disc is located, and the ventilation ring structure is used to supplement the air volume to the air-powder mixing area between the central cone and the mill shell or to suck and discharge the powdery material in the air-powder mixing area to the outside of the vertical mill device. The ventilation ring structure is arranged below the highest position of the grinding roller.

2. A multi-vent roller mill device as claimed in claim 1, wherein: The ventilation ring structure comprises a ring-shaped ventilation cavity, a mill internal ventilation interface, and a plurality of ventilation ports. The ring-shaped ventilation cavity is arranged on the inner side of the mill shell, the mill internal ventilation interface is connected to the outer side of the ring-shaped ventilation cavity, and the mill internal ventilation interface is arranged on the mill shell. The plurality of ventilation ports are arranged on the outer side of the ring-shaped ventilation cavity.

3. A multi-vent roller mill device as claimed in claim 1, wherein: The ventilation ring structure comprises a ring-shaped ventilation cavity, a mill internal ventilation interface, and a mill internal ventilation pipe. The ring-shaped ventilation cavity is arranged on the outer side of the central cone. The mill internal ventilation interface is connected to the upper part of the outer side of the ring-shaped ventilation cavity through the mill internal ventilation pipe. The mill internal ventilation interface is arranged on the mill shell. The plurality of ventilation ports are arranged on the lower part of the outer side of the ring-shaped ventilation cavity.

4. A multi-vent roller mill device as claimed in claim 3, wherein: The mill internal ventilation interface is connected to the feeding port of the magnetic separator through an air induction fan. The discharging port of the magnetic separator is connected to the mill return port. The mill return port is arranged on the mill shell.

5. A multi-vent roller mill device according to claim 2 or 3, wherein: The ventilation ports are provided with guide plates for guiding the air flow of the ventilation ports. The guide plates are deflected along the rotation direction of the grinding disc.

6. A multi-vent roller mill device as claimed in claim 5, wherein: The included angle α between the guide plates and the symmetry axis of the ring-shaped ventilation cavity is 10-80°.

7. A method of operating a vertical mill device as claimed in claim 1, characterized in that: The air volume required for the pneumatic conveying of the completed material is introduced into the air-powder mixing area in the mill shell through the tuyere ring. When the air volume introduced by the tuyere ring cannot meet the requirement of material drying, the supplementary air volume is introduced into the air-powder mixing area between the central cone and the mill shell through the ventilation ring structure. When the air volume introduced by the tuyere ring can meet the requirement of material drying, the powdery material in the air-powder mixing area is sucked and discharged to the vertical mill device through the ventilation ring structure. The powdery material sucked and discharged is separated into magnetic and non-magnetic substances through the magnetic separation equipment. The non-magnetic or magnetic substances at the particle size scale of the material are removed as required, and the remaining material is returned to the vertical mill device for continuous grinding.

8. A method of operating a vertical mill device according to claim 7, characterized in that: When grinding magnetic iron ore, the non-magnetic substances are removed through the magnetic separation equipment to improve the quality of the magnetic iron ore powder. When grinding steel slag, the magnetic substances are removed through the magnetic separation equipment to improve the activity of the steel slag powder.

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