A high efficiency vertical mill system and method of use thereof

Abstract

A high-efficiency vertical mill system, relating to the field of vertical mill technology, includes: a feeding and conveying group; a powder classifier group connected to the discharge end of the feeding and conveying group, the powder classifier group including a qualified discharge end and an unqualified discharge end; a vertical mill group connected to the unqualified discharge end of the powder classifier group, the discharge end of the vertical mill group being connected to the feeding and conveying group; and a finished product collection and conveying group connected to the qualified discharge end of the powder classifier group. The invention also provides a method for using the high-efficiency vertical mill system. The invention employs an external circulation method, separating and returning the material after grinding outside the vertical mill components, avoiding high-speed scouring and wear of the grinding rollers and the inner wall of the vertical mill by the ground material (finished product and coarse powder), significantly reducing equipment maintenance costs, extending the overall service life of the machine, and also avoiding the problems of "over-grinding" or "under-grinding" caused by the invisible internal circulation, ensuring the quality of the final product.

Description

Technical Field

[0001] This invention relates to the field of vertical mill technology, and more specifically to a high-efficiency vertical mill system and its usage method. Background Technology

[0002] A vertical mill system is a powder production line centered around a vertical mill. The working principle of this system is that the electric motor of the vertical mill drives a reducer to rotate the grinding disc at a uniform speed. Material is then fed into the central area of ​​the grinding disc through a feed pipe. Under the centrifugal force of the rotating grinding disc, the material moves towards the edge of the disc. Material moving directly in front of the grinding rollers is subjected to high-intensity compression and crushing between the rollers and the grinding disc, gradually breaking down and refining the material particles. The crushed material overflows from the edge of the grinding disc and is carried by a high-speed upward hot airflow from the air ring to the classifier integrated with the vertical mill. The coarse powder is returned to the grinding disc for re-grinding, while the fine powder exits the mill with the airflow and is collected in the system's dust collection device, becoming the final product.

[0003] The vertical mill system described above uses an internal circulation method to ensure that the material is fully ground. However, in this circulation method, the high-speed upward airflow generated by the air ring will cause the crushed material to scour the grinding rollers and the inner wall of the vertical mill at high speed, resulting in wear and affecting the service life. Furthermore, the internal circulation method makes it impossible for personnel to visually observe the grinding status of the material, which can easily lead to problems of "over-grinding" or "under-grinding", affecting the quality of the final product. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a high-efficiency vertical mill system and its usage method, so as to solve the problems of easy equipment wear and uncontrollable material grinding degree in the existing internal circulation vertical mill system.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A high-efficiency vertical mill system includes:

[0007] Feeding conveyor assembly;

[0008] A powder sorting unit is connected to the discharge end of the feeding and conveying unit, and the powder sorting unit includes a qualified discharge end and an unqualified discharge end;

[0009] The vertical mill unit is connected to the unqualified discharge end of the classifier unit, and the discharge end of the vertical mill unit is connected to the feeding conveyor unit; and

[0010] The finished product collection and conveying unit is connected to the qualified discharge end of the powder sorting unit.

[0011] Preferably, the feeding conveyor group includes a mill feed metering conveyor belt and an elevator connected in sequence. The discharge end of the elevator is connected to the sorting group. The mill feed metering conveyor belt is equipped with an iron remover. The mill feed metering conveyor belt is also connected to the mill discharge conveyor equipment, which is connected to the discharge end of the vertical mill group.

[0012] Preferably, the mill discharge conveying equipment includes two mill discharge belt conveyors connected in sequence. The mill discharge belt conveyor at the front end is connected to the discharge end of the vertical mill, and the mill discharge belt conveyor at the rear end is connected to the mill feed metering conveyor belt.

[0013] Preferably, the classifying unit includes a dynamic classifier and a V-type classifier arranged vertically in sequence. The dynamic classifier includes a qualified discharge end and an unqualified discharge end. The V-type classifier includes a coarse powder discharge end and a fine powder discharge end. The feed end of the dynamic classifier is connected to the fine powder discharge end of the V-type classifier. The qualified discharge end of the dynamic classifier is connected to the feed end of the finished product collection and conveying unit. The unqualified discharge end of the dynamic classifier and the coarse powder discharge end of the V-type classifier are both connected to the feed end of the vertical mill unit. The feed end of the V-type classifier is connected to the discharge end of the elevator.

[0014] Preferably, the vertical mill assembly includes a vertically arranged vertical mill, the feed end of which is connected to the unqualified discharge end of the dynamic classifier and the coarse powder discharge end of the V-type classifier, and the discharge end of the vertical mill is connected to the mill discharge belt conveyor located at the front end.

[0015] Preferably, the finished product collection and conveying group includes a cyclone separator, a bag filter, a first air conveying chute, and a second air conveying chute. The feed end of the cyclone separator is connected to the qualified discharge end of the dynamic air classifier, the upper discharge end of the cyclone separator is connected to the feed end of the bag filter, the first air conveying chute is connected to the discharge end of the bag filter, and the second air conveying chute is connected to both the lower discharge end of the cyclone separator and the discharge end of the first air conveying chute.

[0016] Preferably, airlock valves are provided between the unqualified discharge end of the dynamic classifier and the coarse powder discharge end of the V-type classifier and the vertical mill, as well as between the lower discharge end of the cyclone and the discharge end of the first air conveying chute and the second air conveying chute.

[0017] Preferably, the vertical mill includes a grinding disc that is horizontally rotatably disposed on its lower side, a plurality of grinding rollers that are evenly distributed along the circumference of the grinding disc and rotate against the upper part, and a material collection area disposed below the grinding disc. A high-efficiency material distribution device is provided between the feed end of the vertical mill, the grinding disc, and the plurality of grinding rollers. The feed end of the high-efficiency material distribution device is connected to the feed end of the vertical mill. The high-efficiency material distribution device has a plurality of discharge ends that are arranged one-to-one with the plurality of grinding rollers and the grinding disc. A plurality of first scrapers are provided along the circumference of the lower part of the grinding disc. The plurality of first scrapers are located in the material collection area. The material collection area is connected to the discharge port disposed on one side of the lower part of the vertical mill.

[0018] Preferably, there are three grinding rollers, and two baffle rings with different radii are coaxially fixedly installed on the upper part of the grinding disc. Several grinding rollers are located between the two baffle rings. The high-efficiency material distribution device includes a collection hopper, three sets of distribution pipes, and three sets of second scrapers. The collection hopper is set at the feed end of the vertical mill and is connected to the unqualified discharge end of the dynamic classifier and the coarse powder discharge end of the V-type classifier. One end of each distribution pipe is connected to the discharge end of the collection hopper, and the other end is arranged between the corresponding grinding roller, the two baffle rings, and the grinding disc. The three sets of second scrapers are fixedly installed one by one on the discharge end of the three-part distribution pipe and located between the two baffle rings.

[0019] This invention also provides a method for using a high-efficiency vertical mill system, comprising the following steps:

[0020] S1. After the material to be ground is coarsely selected by the mill metering conveyor belt, elevator, V-type classifier, and finely selected by the dynamic classifier, the qualified material is collected by the cyclone and bag dust collector and then transported to the next process through the first air conveying chute and the second air conveying chute.

[0021] S2. In step S1, the unqualified materials after coarse selection by the V-type classifier and fine selection by the dynamic classifier are sent to the collection hopper and then fed into the corresponding grinding roller, two baffle rings and grinding disc through each distribution pipe for grinding. The ground material is scraped into the collection area by three second scrapers and then scraped into the discharge port by several first scrapers and discharged from the vertical mill.

[0022] S3. In step S2, the material discharged from the vertical mill passes through two mill exit belt conveyors and is then sent to the mill inlet metering conveyor belt, repeating steps S1-S2 together with the material to be ground, thus realizing the external circulation of the vertical mill system.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. This invention employs an external circulation method, separating the sorting and return processes of the ground materials from the outside of the vertical mill assembly. After grinding within the vertical mill, the materials are directly discharged, no longer relying on the high-speed upward hot airflow generated by the air ring for internal circulation and sorting. This completely avoids the high-speed scouring and wear of the grinding rollers and the inner wall of the vertical mill by the ground materials (finished products and coarse powder), significantly reducing equipment maintenance costs and extending the overall service life of the machine.

[0025] 2. This invention achieves multi-stage, controllable sorting of materials before and after grinding by setting up independent powder sorting groups (V-type powder sorter + dynamic powder sorter). Materials that fail grinding are returned to the feeding and conveying group via a circulation group to re-enter the powder sorting and grinding process. The entire circulation process can be monitored and controlled externally. Compared to internal circulation methods, operators can directly monitor the grinding status of the materials, avoiding problems of "over-grinding" or "under-grinding" caused by the lack of visibility in internal circulation, thus ensuring the quality of the final product.

[0026] 3. The vertical mill assembly of this invention is equipped with a high-efficiency material distribution device, which can evenly distribute the material between several grinding rollers and the grinding disc. Combined with a double-baffle ring structure, this ensures a more uniform material distribution on the grinding disc and a more rational grinding path. Simultaneously, the ground material is forcibly discharged through the first and second scrapers, preventing material accumulation under the grinding disc and accelerating material circulation. Overall, the effective grinding times per unit time are increased, and the system's processing capacity is significantly improved.

[0027] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0028] Figure 1 This is a process flow diagram of the present invention.

[0029] Figure 2 for Figure 1 A top view showing the assembly of the central feed tube, grinding roller, and grinding disc.

[0030] The numbers in the diagram are as follows: 1. Feed metering conveyor belt; 11. Iron separator; 2. Elevator; 3. V-type classifier; 31. Dynamic classifier; 4. Airlock valve; 5. Vertical mill; 51. Grinding disc; 52. Material retaining ring; 53. Grinding roller; 54. First scraper; 55. Collection area; 56. Discharge port; 57. Feed conveyor belt; 6. Collection hopper; 61. Distribution pipe; 62. Second scraper; 7. Cyclone; 8. Bag filter; 81. First air conveying chute; 9. Second air conveying chute. Detailed Implementation

[0031] To make the technical means, creative features, objectives, and effects of this invention clearer and easier to understand, the invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0032] like Figure 1-2 As shown, an embodiment of the present invention provides a high-efficiency vertical mill system, comprising: a feeding and conveying group; a classifying group connected to the discharge end of the feeding and conveying group, the classifying group including a qualified discharge end and an unqualified discharge end; a vertical mill group connected to the unqualified discharge end of the classifying group, the discharge end of the vertical mill group being connected to the feeding and conveying group; and a finished product collection and conveying group connected to the qualified discharge end of the classifying group.

[0033] The feeding and conveying group includes a feed metering conveyor belt 1 and an elevator 2 connected in sequence. The discharge end of the elevator 2 is connected to the sorting group. The feed metering conveyor belt 1 is equipped with a magnetic separator 11 and is also connected to the discharge conveyor equipment, which is connected to the discharge end of the vertical mill group. The discharge conveyor equipment includes two discharge belt conveyors 57 connected in sequence. The discharge belt conveyor 57 at the front end is connected to the discharge end of the vertical mill 5, and the discharge belt conveyor 57 at the rear end is connected to the feed metering conveyor belt 1. The magnetic separator 11 can adsorb and remove magnetic impurities such as scrap iron from the material.

[0034] The classifying unit includes a dynamic classifier 31 and a V-type classifier 3 arranged vertically in sequence. The dynamic classifier 31 includes a qualified discharge end and an unqualified discharge end. The V-type classifier 3 includes a coarse powder discharge end and a fine powder discharge end. The feed end of the dynamic classifier 31 is connected to the fine powder discharge end of the V-type classifier 3. The qualified discharge end of the dynamic classifier 31 is connected to the feed end of the finished product collection and conveying unit. The unqualified discharge end of the dynamic classifier 31 and the coarse powder discharge end of the V-type classifier 3 are both connected to the feed end of the vertical mill unit. The feed end of the V-type classifier 3 is connected to the discharge end of the elevator 2.

[0035] The V-type classifier 3 is responsible for coarsely selecting the material sent by the elevator 2. The fine powder after coarse selection enters the dynamic classifier 31 for fine selection. The qualified products selected by the dynamic classifier 31 enter the finished product collection and conveying group, while the coarse powder that fails to pass the coarse selection by the V-type classifier 3 and the material that fails to pass the fine selection by the dynamic classifier 31 are sent to the vertical mill group for grinding.

[0036] The vertical mill assembly includes a vertically arranged vertical mill 5. The feed end of the vertical mill 5 is connected to the unqualified discharge end of the dynamic classifier 31 and the coarse powder discharge end of the V-type classifier 3. The discharge end of the vertical mill 5 is connected to the mill discharge belt conveyor 57 located at the front end.

[0037] The finished product collection and conveying assembly includes a cyclone 7, a bag filter 8, a first air conveying chute 81, and a second air conveying chute 9. The feed end of the cyclone 7 is connected to the qualified discharge end of the dynamic classifier 31, the upper discharge end of the cyclone 7 is connected to the feed end of the bag filter 8, the first air conveying chute 81 is connected to the discharge end of the bag filter 8, and the second air conveying chute 9 is connected to both the lower discharge end of the cyclone 7 and the discharge end of the first air conveying chute 81.

[0038] The cyclone separator 7 performs preliminary separation of qualified materials from the dynamic classifier 31. Larger particles are discharged through the lower discharge end of the cyclone separator 7 and fall onto the second air conveying chute 9, then are sent to the next process. Smaller particles are collected in the bag filter 8 through the upper discharge end of the cyclone separator 7, and then conveyed to the next process through the first air conveying chute 81 and the second air conveying chute 9.

[0039] Airlock valves 4 are provided between the unqualified discharge end of the dynamic classifier 31 and the coarse powder discharge end of the V-type classifier 3 and the vertical mill 5, as well as between the lower discharge end of the cyclone 7 and the discharge end of the first air conveying chute 81 and the second air conveying chute 9. The airlock valves 4 can ensure airtightness during the unloading process, and ensure the stability and safety of unloading.

[0040] The vertical mill 5 includes a grinding disc 51 horizontally rotatably mounted on its lower side, several grinding rollers 53 evenly distributed around the circumference of the grinding disc 51 and rotating against the upper part, and a material collection area 55 located below the grinding disc 51. A high-efficiency material distribution device is provided between the feed end of the vertical mill 5, the grinding disc 51, and the several grinding rollers 53. The feed end of the high-efficiency material distribution device is connected to the feed end of the vertical mill 5. The high-efficiency material distribution device has several discharge ends, which are arranged one-to-one between the several grinding rollers 53 and the grinding disc 51. Several first scrapers 54 are provided around the lower part of the grinding disc 51. The several first scrapers 54 are located in the material collection area 55. The material collection area 55 is connected to the discharge port 56 located on one side of the lower part of the vertical mill 5. The material entering the vertical mill 5 is accurately delivered to the several grinding rollers 53 and the grinding disc 51 for grinding by the high-efficiency material distribution device, which reduces the ineffective movement of the material on the grinding disc 51, shortens the grinding time, and improves the grinding efficiency.

[0041] Preferably, there are three grinding rollers 53, and two baffle rings 52 with different radii are coaxially fixedly installed on the upper part of the grinding disc 51. Several grinding rollers 53 are located between the two baffle rings 52. The high-efficiency material distribution device includes a collection hopper 6, three sets of distribution pipes 61, and three sets of second scrapers 62. The collection hopper 6 is located at the feed end of the vertical mill 5 and is connected to the unqualified discharge end of the dynamic classifier 31 and the coarse powder discharge end of the V-type classifier 3. One end of each distribution pipe 61 is connected to the discharge end of the collection hopper 6, and the other end is directly opposite the corresponding grinding roller 53, the two baffle rings 52, and the grinding disc 51. The arrangement involves three sets of second scrapers 62, each fixedly installed on the discharge end of the three-component feeding pipe 61 and positioned between the two baffle rings 52. The material passes through the collecting hopper 6 and the three-component feeding pipe 61, accurately falling between the three grinding rollers 53, the grinding disc 51, and the two baffle rings 52 for grinding. During the grinding process, the three sets of second scrapers 62 scrape the ground material out of the two baffle rings and overflows from the edge of the grinding disc 51 through centrifugal force, falling into the collecting area 55. Then, the material is scraped out of the discharge port 56 by several first scrapers 54 and falls onto the mill discharge belt conveyor 57 for external circulation.

[0042] The number of grinding rollers 53 is not limited to three; it can be two or more. The specific number depends on the working conditions. The number of material distribution pipes 61 and the second scraper 62 is the same as the number of grinding rollers 53.

[0043] During the grinding process, the grinding disc 51 rotates at a speed of 15~30 r / min, and the preset crushing pressure of the grinding roller 53 is 8~15 MPa. This parameter range can adapt to the grinding needs of most powder materials, ensuring grinding efficiency and grinding effect. The preset particle size screening standard of the dynamic V-type classifier 3 is 80~200μm, and the classification efficiency of the dynamic classifier 31 is ≥90%, ensuring the particle size accuracy of qualified materials and improving product quality.

[0044] The specific structure, connection method, operating principle, and supporting equipment used in normal operation of the above-mentioned mill feed metering conveyor belt 1, iron remover 11, elevator 2, V-type classifier 3, dynamic classifier 31, airlock valve 4, vertical mill 5, mill discharge belt conveyor 57, cyclone 7, bag filter 8, first air conveying chute 81, and second air conveying chute 9 are all existing technologies and will not be described in detail here.

[0045] This invention also provides a method for using a high-efficiency vertical mill system, comprising the following steps:

[0046] S1. The material to be ground is coarsely selected by the mill metering conveyor belt 1, elevator 2, V-type classifier 3, and finely selected by dynamic classifier 31. The qualified material is collected by cyclone 7 and bag dust collector 8 and then conveyed to the next process through the first air conveying chute 81 and the second air conveying chute 9.

[0047] S2. In step S1, the unqualified materials after coarse selection by V-type classifier 3 and fine selection by dynamic classifier 31 are sent to collection hopper 6 and then fed into the corresponding grinding roller 53, two baffle rings 52 and grinding disc 51 through each distribution pipe 61 for grinding. The ground material is scraped into collection area 55 by three second scrapers 62 and then scraped into discharge port 56 by several first scrapers 54 and discharged from vertical mill 5.

[0048] S3. In step S2, the material discharged from the vertical mill 5 passes through two mill exit belt conveyors 57 and is then sent to the mill metering conveyor belt 1. Together with the material to be ground, steps S1-S2 are repeated to realize the external circulation of the vertical mill system.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A high-efficiency vertical mill system, characterized in that, include: Feeding conveyor assembly; A powder sorting unit is connected to the discharge end of the feeding and conveying unit, and the powder sorting unit includes a qualified discharge end and an unqualified discharge end; The vertical mill unit is connected to the unqualified discharge end of the classifier unit, and the discharge end of the vertical mill unit is connected to the feeding conveyor unit; and The finished product collection and conveying unit is connected to the qualified discharge end of the powder sorting unit.

2. The high-efficiency vertical mill system according to claim 1, characterized in that, The feeding conveyor group includes a mill feed metering conveyor belt (1) and an elevator (2) connected in sequence. The discharge end of the elevator (2) is connected to the sorting group. The mill feed metering conveyor belt (1) is equipped with an iron remover (11). The mill feed metering conveyor belt (1) is also connected to the mill discharge conveyor. The mill discharge conveyor is connected to the discharge end of the vertical mill group.

3. The high-efficiency vertical mill system according to claim 2, characterized in that, The mill discharge conveying equipment includes two mill discharge belt conveyors (57) connected in sequence. The mill discharge belt conveyor (57) at the front end is connected to the discharge end of the vertical mill (5), and the mill discharge belt conveyor (57) at the rear end is connected to the mill feed metering conveyor belt (1).

4. The high-efficiency vertical mill system according to claim 3, characterized in that, The powder classifier group includes a dynamic powder classifier (31) and a V-type powder classifier (3) arranged vertically in sequence. The dynamic powder classifier (31) includes a qualified discharge end and an unqualified discharge end. The V-type powder classifier (3) includes a coarse powder discharge end and a fine powder discharge end. The feed end of the dynamic powder classifier (31) is connected to the fine powder discharge end of the V-type powder classifier (3). The qualified discharge end of the dynamic powder classifier (31) is connected to the feed end of the finished product collection and conveying group. The unqualified discharge end of the dynamic powder classifier (31) and the coarse powder discharge end of the V-type powder classifier (3) are both connected to the feed end of the vertical mill group. The feed end of the V-type powder classifier (3) is connected to the discharge end of the elevator (2).

5. The high-efficiency vertical mill system according to claim 4, characterized in that, The vertical mill assembly includes a vertically arranged vertical mill (5). The feed end of the vertical mill (5) is connected to the unqualified discharge end of the dynamic classifier (31) and the coarse powder discharge end of the V-type classifier (3). The discharge end of the vertical mill (5) is connected to the mill discharge belt conveyor (57) located at the front end.

6. The high-efficiency vertical mill system according to claim 4, characterized in that, The finished product collection and conveying group includes a cyclone (7), a bag filter (8), a first air conveying chute (81), and a second air conveying chute (9). The feed end of the cyclone (7) is connected to the qualified discharge end of the dynamic classifier (31), the upper discharge end of the cyclone (7) is connected to the feed end of the bag filter (8), the first air conveying chute (81) is connected to the discharge end of the bag filter (8), and the second air conveying chute (9) is connected to both the lower discharge end of the cyclone (7) and the discharge end of the first air conveying chute (81).

7. The high-efficiency vertical mill system according to claim 6, characterized in that, Airlock valves (4) are provided between the unqualified discharge end of the dynamic classifier (31), the coarse powder discharge end of the V-type classifier (3) and the vertical mill (5), as well as between the lower discharge end of the cyclone (7) and the discharge end of the first air conveying chute (81) and the second air conveying chute (9).

8. The high-efficiency vertical mill system according to claim 5, characterized in that, The vertical mill (5) includes a grinding disc (51) that is horizontally rotatably disposed on its lower side, a plurality of grinding rollers (53) that are evenly distributed along the circumference of the grinding disc (51) and rotate against the upper part, and a material collection area (55) disposed below the grinding disc (51). A high-efficiency material distribution device is provided between the feed end of the vertical mill (5), the grinding disc (51), and the plurality of grinding rollers (53). The feed end of the high-efficiency material distribution device is connected to the feed end of the vertical mill (5). The high-efficiency material distribution device has a plurality of discharge ends that are arranged one-to-one with the plurality of grinding rollers (53) and the grinding disc (51). A plurality of first scrapers (54) are provided along the circumference of the lower part of the grinding disc (51). The plurality of first scrapers (54) are located in the material collection area (55). The material collection area (55) is connected to the discharge port (56) disposed on one side of the lower part of the vertical mill (5).

9. The high-efficiency vertical mill system according to claim 8, characterized in that, There are three grinding rollers (53). Two baffle rings (52) with different radii are coaxially fixed on the upper part of the grinding disc (51). Several grinding rollers (53) are located between the two baffle rings (52). The high-efficiency material distribution device includes a material collection hopper (6), three sets of material distribution pipes (61) and three sets of second scrapers (62). The material collection hopper (6) is set at the feed end of the vertical mill (5) and is connected to the unqualified discharge end of the dynamic classifier (31) and the coarse powder discharge end of the V-type classifier (3). One end of each material distribution pipe (61) is connected to the discharge end of the material collection hopper (6), and the other end is arranged between the corresponding grinding roller (53), the two baffle rings (52) and the grinding disc (51). The three sets of second scrapers (62) are fixedly installed on the discharge end of the three sets of material distribution pipes (61) and are located between the two baffle rings (52).

10. A method of using a high-efficiency vertical mill system according to any one of claims 1-9, characterized in that, Includes the following steps: S1. The material to be ground is coarsely selected by the mill metering conveyor belt (1), elevator (2), V-type classifier (3), and finely selected by the dynamic classifier (31). The qualified material is collected by the cyclone (7) and bag filter (8) and then transported to the next process through the first air conveying chute (81) and the second air conveying chute (9). S2. In step S1, the unqualified materials after coarse selection by the V-type classifier (3) and fine selection by the dynamic classifier (31) are sent to the collection hopper (6) and then fed into the corresponding grinding roller (53), two baffle rings (52) and grinding disc (51) through each distribution pipe (61) for grinding. The ground material is scraped into the collection area (55) by three second scrapers (62) and then scraped into the discharge port (56) by several first scrapers (54) and discharged from the vertical mill (5). S3. In step S2, the material discharged from the vertical mill (5) passes through two mill exit belt conveyors (57) and is then sent to the mill metering conveyor belt (1), repeating steps S1-S2 together with the material to be ground, to realize the external circulation of the vertical mill system.

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