A cement grinding system and a grinding method

Abstract

The application relates to the technical field of cement grinding, and provides a cement grinding system and a grinding method, which comprise a conveying device, a first bucket elevator, a steady flow bin, a roller press, a second bucket elevator, a screening device and a ball mill; the material inlet end of the first bucket elevator is located below the material outlet end of the conveying device; the material outlet end of the first bucket elevator is provided with a first conveying pipe which conveys materials to the inside of the steady flow bin; the steady flow bin is installed on the roller press; the lower end of the roller press is provided with a second conveying pipe which conveys materials to the material inlet end of the second bucket elevator; the material outlet end of the second bucket elevator is provided with a third conveying pipe which conveys materials to the screening device; and the lower end of the screening device is provided with a fourth conveying pipe which conveys materials to the inside of the ball mill. The second bucket elevator and the screening device are additionally arranged, the crushed materials of the roller press are sorted into the ball mill, the system circulation load is reduced, and the energy efficiency index of the grinding system is improved.

Description

Technical Field

[0001] This invention relates to the field of cement grinding technology, and more specifically, to a cement grinding system and grinding method. Background Technology

[0002] Currently, roller presses are widely used in the cement industry for grinding raw materials and cement. When roller presses are used for cement grinding, they are mainly used in combination with ball mills to ensure the quality of the final cement products.

[0003] In traditional cement roller press grinding systems, materials are crushed by the roller press and then directly enter the mill. Some materials are returned to the roller press for further crushing. Because the particle size of the material exiting the roller press is random and uncontrollable, large balls need to be installed in the mill to ensure the crushing and grinding of coarse particles. When the number of large balls inside the mill increases, the total number of steel balls decreases, reducing the grinding effect of the steel balls on the material. This results in a lower hourly output of the mill and an increase in system energy consumption. Since the material returning to the roller press contains a large amount of fine powder, the ineffective work of the roller press increases. Furthermore, excessive fine powder can lead to a smaller gap between the rollers, increasing the circulating load, reducing the efficiency of the roller press, accelerating roller surface wear, and increasing the frequency of roller press maintenance. Summary of the Invention

[0004] The purpose of this invention is to provide a cement grinding system and grinding method, by adding a screening device to sort the material after crushing by the roller press before it enters the mill, thereby reducing the system's circulating load and improving the energy efficiency of the grinding system.

[0005] This invention provides a cement grinding system, which adopts the following technical solution:

[0006] A cement grinding system includes a conveying device, a first bucket elevator, a stabilizing bin, a roller press, a second bucket elevator, a screening device, a ball mill, and a dust collector. The feed end of the first bucket elevator is located below the discharge end of the conveying device. The discharge end of the first bucket elevator is provided with a first conveying pipe for conveying material into the stabilizing bin. The stabilizing bin is mounted on the roller press. The lower end of the roller press is provided with a second conveying pipe for conveying material into the feed end of the second bucket elevator. The discharge end of the second bucket elevator is provided with a third conveying pipe for conveying material into the screening device. The lower end of the screening device is provided with a fourth conveying pipe for conveying material into the ball mill. The input end of the dust collector is connected to the conveying device, the first bucket elevator, the screening device, and the second bucket elevator, respectively, and is used to collect dust generated during the operation of the conveying device, the first bucket elevator, the screening device, and the second bucket elevator.

[0007] Preferably, the screening device is connected to a first return powder pipe, which is connected to the first conveying pipe.

[0008] Preferably, the screening device is equipped with a three-way valve and a second return powder pipe, the first return powder pipe and the fourth conveying pipe are respectively connected to the three-way valve, and the second return powder pipe is connected to the first conveying pipe.

[0009] Preferably, the screening device is a double-drum drum screen, driven by a variable frequency motor.

[0010] Preferably, the conveying device is a conveyor belt.

[0011] Preferably, the flow stabilizing bin is equipped with a weighing sensor level gauge.

[0012] Preferably, an airlock valve is provided at the connection end between the fourth conveying pipe and the ball mill, and an iron remover is provided on the fourth conveying pipe.

[0013] The present invention also provides a cement grinding method, comprising the following steps:

[0014] S1: The material is conveyed to the feed end of the first bucket elevator using a conveying device;

[0015] S2: The first bucket elevator conveys the material to the first conveying pipe, and the first conveying pipe conveys the material to the interior of the stabilizing bin;

[0016] S3: The stabilizing hopper feeds material into the roller press, which crushes the material. The crushed material is then conveyed through the second conveying pipe to the feed end of the second bucket elevator.

[0017] S4: The second bucket elevator conveys the material to the third conveying pipe. The conveying capacity of the second bucket elevator is 380t / h. The third conveying pipe conveys the material to the screening device, which screens the material. The material with a particle size of less than or equal to 3mm enters the fourth conveying pipe. The fourth conveying pipe conveys the material to the inside of the ball mill for grinding. The material with a particle size greater than 3mm is sent to the first conveying pipe through the second return powder pipe. The first conveying pipe conveys the material to the inside of the stabilizing chamber for secondary extrusion by the roller press.

[0018] Preferably, in S4, when the discharge of fine powder material is too large and the ball mill cannot consume it completely, the three-way valve is adjusted, and a portion of the material is guided into the stabilizing chamber through the first return powder pipe, and this portion of material is screened and squeezed multiple times.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] This invention adds a second bucket elevator and a screening device to the existing cement grinding system. The second bucket elevator transports the material extruded by the roller press to the screening device, which then screens the material. The fine powder in the material is then transported to the ball mill, which uses only small balls. With a fixed ball load, the total number of steel balls increases, improving the grinding effect of the steel balls on the material and increasing the hourly output of the ball mill. The coarse particles in the material are returned to the roller press for secondary extrusion, avoiding the impact of excessive fine powder on the normal operation of the roller press, improving the effective work of the roller press, reducing the crushing burden on the ball mill, and thus significantly improving the energy efficiency of the grinding system. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of an existing pre-grinding cement grinding system;

[0023] Figure 2 This is a schematic diagram of the structure of a cement grinding system in some embodiments of the present invention;

[0024] Figure 3 for Figure 2 Enlarged view of the structure at point A in the middle.

[0025] The reference numerals in the attached figures are as follows:

[0026] 1. Conveying device; 2. First bucket elevator; 3. Flow stabilizing bin; 4. Roller press; 5. Second bucket elevator; 6. Screening device; 7. Ball mill; 8. First conveying pipe; 9. Second conveying pipe; 10. Third conveying pipe; 11. Fourth conveying pipe; 12. First return powder pipe; 13. Three-way valve; 14. Second return powder pipe; 15. Dust collector; 16. Weighing sensor level gauge; 17. Airlock valve; 18. Iron separator. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0029] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0030] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0031] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0032] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0033] Example

[0034] like Figure 1-3As shown, the cement grinding system of this embodiment includes a conveying device 1, a first bucket elevator 2, a flow stabilizing bin 3, a roller press 4, a second bucket elevator 5, a screening device 6, and a ball mill 7. The feed end of the first bucket elevator 2 is located below the discharge end of the conveying device 1. The discharge end of the first bucket elevator 2 is provided with a first conveying pipe 8, which is used to convey materials into the flow stabilizing bin 3. The flow stabilizing bin 3 is installed on the roller press 4. The lower end of the roller press 4 is provided with a second conveying pipe 9, which is used to convey materials into the feed end of the second bucket elevator 5. The discharge end of the second bucket elevator 5 is provided with a third conveying pipe 10, which is used to convey materials into the screening device 6. The lower end of the screening device 6 is provided with a fourth conveying pipe 11, which is used to convey materials into the ball mill 7.

[0035] During operation, the conveying device 1 transports material to the feed end of the first bucket elevator 2, which then transports it to the first conveying pipe 8. The first conveying pipe 8 then transports the material to the stabilizing silo 3, which feeds material into the roller press 4. The roller press 4 crushes and squeezes the material. The crushed material enters the feed end of the second bucket elevator 5 through the second conveying pipe 9. The second bucket elevator 5 transports the material to the third conveying pipe 10, which guides the material into the screening device 6. The screening device 6 screens the material, and the material that meets the particle size requirements is sent to the ball mill 7 for grinding through the fourth conveying pipe 11. The material that does not meet the particle size requirements is recycled. The material is fed back into the roller press 4 for crushing and extrusion, thus preventing excessive fine powder from entering the roller press 4 and improving the stability of its operation. Since the ball mill 7 only accepts fine powder, it can use only small balls. With a fixed ball load, the total number of steel balls increases, improving the grinding effect of the steel balls on the material and increasing the hourly output of the ball mill 7. The addition of a second bucket elevator 5 and a screening device 6 sorts the material after crushing by the roller press 4 before it enters the mill, improving the existing pre-grinding system where the material is directly fed into the mill after being squeezed and separated by the roller press, resulting in random and uncontrolled particle size and a lagging process line. This improves the energy efficiency of the grinding system.

[0036] In this embodiment, the screening device 6 is connected to a first return powder pipe 12, which is connected to a first conveying pipe 8. The screening device 6 is equipped with a three-way valve 13 and a second return powder pipe 14. The first return powder pipe 12 and the fourth conveying pipe 11 are respectively connected to the three-way valve 13. The second return powder pipe 14 is connected to the first conveying pipe 8. By setting the second return powder pipe 14, it is convenient to send the unqualified material after screening by the screening device 6 into the interior of the first conveying pipe 8. The first conveying pipe 8 conveys this part of the material to the interior of the flow stabilizing chamber 3. The roller press 4 crushes this part of the material again. By adjusting the three-way valve 13, it is convenient to change the flow direction of the qualified material after screening by the screening device 6 according to the usage requirements.

[0037] In this embodiment, the cement grinding system also includes a dust collector 15. The input end of the dust collector 15 is connected to the conveying device 1, the first bucket elevator 2, the screening device 6, and the second bucket elevator 5, respectively. The dust collector 15 adopts an FMQD32-4 type air box pulse bag dust collector to increase the dust collection air volume. The dust collector 15 is used to collect the dust generated during the operation of the conveying device 1, the first bucket elevator 2, the screening device 6, and the second bucket elevator 5.

[0038] In this embodiment, the screening device 6 is a double-drum drum screen, driven by a variable frequency motor. The double-drum drum screen can classify the material extruded from the roller press 4 into coarse and fine particles. The coarse particles are returned to the stabilizing chamber 3 for repeated extrusion, thereby strictly controlling the particle size range of the material entering the ball mill 7.

[0039] In this embodiment, the conveying device 1 is a conveyor belt. Conveyor belts are easy to use, easy to maintain, and have low transportation costs. They can also shorten transportation distances, reduce project costs, and save manpower and resources.

[0040] In this embodiment, a weighing sensor level gauge 16 is installed on the steady flow bin 3. The weighing sensor level gauge 16 is used to monitor the material level in the steady flow bin 3, ensuring that the roller press 4 can continuously and stably obtain the required material, avoiding production fluctuations caused by insufficient or excessive material supply, and facilitating timely adjustment of the feeding amount according to changes in material level, optimizing the production process and improving production efficiency.

[0041] In this embodiment, an airlock valve 17 is provided at the connection end between the fourth conveying pipe 11 and the ball mill 7, and an iron remover 18 is provided on the fourth conveying pipe 11. The airlock valve 17 is used to control the material entering the ball mill 7 and prevent gas backflow during the feeding process, so as to maintain the stability of the internal environment of the ball mill 7. The iron remover 18 is used to continuously remove iron impurities from the material, which can protect the ball mill 7 and improve the purity and performance of the product.

[0042] A cement grinding method includes the following steps:

[0043] S1: The material is conveyed to the feed end of the first bucket elevator 2 using the conveying device 1;

[0044] S2: The first bucket elevator 2 conveys the material to the first conveying pipe 8, and the first conveying pipe 8 conveys the material to the interior of the flow stabilizing bin 3;

[0045] S3: The stabilizing chamber 3 feeds material into the roller press 4, the roller press 4 crushes the material, and the crushed material is conveyed to the feed end of the second bucket elevator 5 through the second conveying pipe 9.

[0046] S4: The second bucket elevator 5 conveys the material to the third conveying pipe 10. The conveying capacity of the second bucket elevator 5 is 380t / h. The third conveying pipe 10 conveys the material to the screening device 6. The screening device 6 screens the material. The material with a particle size of less than or equal to 3mm enters the fourth conveying pipe 11. The fourth conveying pipe 11 conveys the material to the inside of the ball mill 7 for grinding. The material with a particle size greater than 3mm is sent to the first conveying pipe 8 through the second return powder pipe 14. The first conveying pipe 8 conveys the material to the inside of the flow stabilizing chamber 3 so that it can be squeezed twice by the roller press 4.

[0047] Distribution of residue at the mill outlet, classifier return powder, finished product, and roller press:

[0048]

[0049] As shown in the table above, after extrusion by roller press 4, the proportion of material with a particle size of 80μm is 41.5%, and the proportion of material with a particle size of less than 3mm is 77%. The proportion of fine powder after extrusion is relatively high, which can be screened.

[0050] The following table compares the main economic and technical indicators before and after the technological upgrade:

[0051]

[0052] As can be seen from the table above, after the material is screened by the screening device 6, the particle size of the material entering the ball mill 7 is greatly reduced, which increases the grinding efficiency of the ball mill 7. At the same time, it improves the effective work of the roller press 4 on the coarse particle return material, and increases the output by more than 10% (about 15 tons) on the existing basis, while reducing the power consumption by 1.5-2 kWh / t.

[0053] In this embodiment, in S4, when the discharge of fine powder material is too large and the ball mill 7 cannot be completely consumed, the three-way valve 13 is adjusted, and a portion of the material is guided into the flow stabilizing chamber 3 by the first return powder pipe 12. This portion of material is screened and squeezed multiple times. Under the premise of meeting the optimal working conditions of the ball mill 7, the material can be further reduced in particle size after being squeezed by the roller press 4 multiple times, thereby improving the grinding effect of the material, increasing the hourly output, and reducing energy consumption.

[0054] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A cement grinding system, characterized in that: The system includes a conveying device, a first bucket elevator, a flow stabilizing bin, a roller press, a second bucket elevator, a screening device, and a ball mill. The feed end of the first bucket elevator is located below the discharge end of the conveying device. The discharge end of the first bucket elevator is provided with a first conveying pipe for conveying material into the flow stabilizing bin. The flow stabilizing bin is mounted on the roller press. The lower end of the roller press is provided with a second conveying pipe for conveying material into the feed end of the second bucket elevator. The discharge end of the second bucket elevator is provided with a third conveying pipe for conveying material into the screening device. The lower end of the screening device is provided with a fourth conveying pipe for conveying material into the ball mill. The screening device is connected to a first powder return pipe, which is connected to the first conveying pipe. The screening device is equipped with a three-way valve and a second return powder pipe. The first return powder pipe and the fourth conveying pipe are respectively connected to the three-way valve, and the second return powder pipe is connected to the first conveying pipe. The steady flow silo is equipped with a weighing sensor level gauge, which is used to monitor the material level in the steady flow silo. When the discharge of fine powder material is too large and the ball mill cannot consume it completely, the three-way valve is adjusted to guide a portion of the material into the steady flow silo through the first return powder pipe, and this portion of material is screened and squeezed multiple times.

2. The cement grinding system according to claim 1, characterized in that: It also includes a dust collector, the input end of which is connected to the conveying device, the first bucket elevator, the screening device and the second bucket elevator respectively, for collecting the dust generated during the operation of the conveying device, the first bucket elevator, the screening device and the second bucket elevator.

3. The cement grinding system according to claim 1, characterized in that: The screening device is a double-drum drum screen, driven by a variable frequency motor.

4. The cement grinding system according to claim 1, characterized in that: The conveying device is a conveyor belt.

5. A cement grinding system according to claim 1, characterized in that: An airlock valve is provided at the connection end between the fourth conveying pipe and the ball mill, and an iron remover is provided on the fourth conveying pipe.

6. A cement grinding method, employing the cement grinding system as described in any one of claims 1-5, characterized in that, Includes the following steps: S1: The material is conveyed to the feed end of the first bucket elevator using a conveying device; S2: The first bucket elevator conveys the material to the first conveying pipe, and the first conveying pipe conveys the material to the interior of the stabilizing bin; S3: The stabilizing hopper feeds material into the roller press, which crushes the material. The crushed material is then conveyed through the second conveying pipe to the feed end of the second bucket elevator. S4: The second bucket elevator conveys the material to the third conveying pipe. The conveying capacity of the second bucket elevator is 380t / h. The third conveying pipe conveys the material to the screening device, which screens the material. The material with a particle size of less than or equal to 3mm enters the fourth conveying pipe. The fourth conveying pipe conveys the material to the inside of the ball mill for grinding. The material with a particle size greater than 3mm is sent to the first conveying pipe through the second return powder pipe. The first conveying pipe conveys the material to the inside of the stabilizing chamber for secondary extrusion by the roller press.

7. A cement grinding method according to claim 6, characterized in that: In S4, when the discharge of fine powder material is too large and the ball mill cannot consume it completely, the three-way valve is adjusted to guide a portion of the material into the stabilizing chamber through the first return powder pipe, and this portion of material is screened and squeezed multiple times.

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