Cement grinding system and grinding method

Abstract

The invention relates to the technical field of cement grinding, and provides a cement grinding system and a grinding method.The cement grinding system comprises 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, and the feeding end of the first bucket elevator is located below the discharging end of the conveying device; a first conveying pipe is arranged at the discharging end of the first bucket elevator and conveys materials into the flow stabilizing bin, the flow stabilizing bin is installed on the roller press, a second conveying pipe is arranged at the lower end of the roller press and conveys materials to the feeding end of the second bucket elevator, and a third conveying pipe is arranged at the discharging end of the second bucket elevator and conveys materials into the flow stabilizing bin. The third conveying pipe conveys materials to the screening device, and a fourth conveying pipe is arranged at the lower end of the screening device and conveys materials into the ball mill. By additionally arranging the second bucket elevator and the screening device, materials crushed by the roller press are sorted and fed into the mill, so that the circulating load of the system is reduced, and the energy efficiency index of the grinding system is improved.

Description

Technical Field

[0001] The invention relates to the technical field of cement grinding, and in particular to a cement grinding system and a grinding method. Background Art

[0002] At present, roller presses are widely used in the cement industry for grinding raw materials, cement and other materials. When roller presses are used for cement grinding, a combined grinding system consisting of a ball mill is mainly used to ensure the quality of the final cement product.

[0003] In the traditional cement roller press grinding system, the material enters the mill directly after being squeezed and crushed by the roller press, and part of the material returns to the roller press for squeezing and crushing. Because the particle size of the material leaving the roller press is random and uncontrolled, large balls need to be configured 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, which reduces the grinding effect of the steel balls on the material, resulting in a lower output per hour of the mill and increased 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, and too much fine powder can easily cause a smaller roller gap between the two rollers of the roller press, increase the circulating load, reduce the efficiency of the roller press, accelerate the wear of the roller surface, and increase the maintenance frequency of the roller press. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a cement grinding system and grinding method, add a screening device to sort the materials crushed by the roller press into the grinding mill, reduce the system circulation load, and improve the energy efficiency index of the grinding system.

[0005] The embodiment of the present invention provides a cement grinding system, which adopts the following technical solutions:

[0006] A cement grinding system comprises a conveying device, a first bucket elevator, a steady flow bin, a roller press, a second bucket elevator, a screening device, a ball mill and a dust collector, wherein the feeding end of the first bucket elevator is located below the discharging end of the conveying device, the discharging end of the first bucket elevator is provided with a first conveying pipe, the first conveying pipe is used to convey 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, the second conveying pipe is used to convey materials to the feeding end of the second bucket elevator, the discharging end of the second bucket elevator is provided with a third conveying pipe, the third conveying pipe is used to convey materials to the screening device, the lower end of the screening device is provided with a fourth conveying pipe, the fourth conveying pipe is used to convey materials to the inside of the ball mill, and the input end of the dust collector is respectively connected to the conveying device, the first bucket elevator, the screening device and the second bucket elevator, and is used to collect dust generated during the working process 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 powder return pipe, and the first powder return pipe is in communication with the first conveying pipe.

[0008] Preferably, a three-way valve is provided on the fourth conveying pipe, the three-way valve is connected to a second powder return pipe, and the second powder return pipe is communicated with 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, a weighing sensor level meter is provided on the steady flow bin.

[0012] Preferably, an air lock 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: using a conveying device to convey the material to the feeding end of the first bucket elevator;

[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 steady flow bin;

[0016] S3: The steady flow bin feeds materials into the roller press, and the roller press squeezes and crushes the materials. The crushed materials are transported to the feeding end of the second bucket elevator through the second conveying pipe;

[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. The screening device is used to screen the material. The material with a particle size 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 first powder return pipe. The first conveying pipe conveys the material to the inside of the steady flow bin for secondary extrusion by the roller press.

[0018] Preferably, in S4, when the discharge amount of fine powder material is too large and the ball mill cannot consume it completely, the three-way valve is adjusted, and a part of the material is diverted into the steady flow bin by the second powder return pipe, and the part of the material is screened and extruded multiple times.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention adds a second bucket elevator and a screening device on the basis of the existing cement grinding system. The second bucket elevator is used to transport the material squeezed by the roller press to the screening device, and the screening device is used to screen the material. The fine powder in the material is sorted and transported to the inside of the ball mill. The ball mill only needs to use small balls. When the ball loading amount is constant, the total number of steel balls increases, which improves the grinding effect of the steel balls on the material and the hourly output of the ball mill. The coarse particles in the material are returned to the roller press for secondary extrusion, which avoids affecting the normal operation of the roller press due to excessive fine powder in the roller press, improves the effective work of the roller press, reduces the crushing burden of the ball mill, and can better improve the energy efficiency index of the grinding system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a structural schematic diagram of an existing pre-grinding cement grinding system;

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

[0024] Figure 3 for Figure 2 A magnified view of the structure in the middle.

[0025] The reference numerals are:

[0026] 1. Conveying device; 2. First bucket elevator; 3. Flow stabilization 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 powder return pipe; 13. Three-way valve; 14. Second powder return pipe; 15. Dust collector; 16. Weighing sensor level meter; 17. Air lock valve; 18. Iron remover. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0029] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

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

[0031] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "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 clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0033] Example

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

[0035] During operation, the conveying device 1 conveys the material to the feeding end of the first bucket elevator 2, the first bucket elevator 2 conveys the material to the first conveying pipe 8, the first conveying pipe 8 then conveys the material to the steady flow bin 3, the steady flow bin 3 is used to feed the inside of the roller press 4, the roller press 4 squeezes and crushes the material, the crushed material enters the feeding end of the second bucket elevator 5 through the second conveying pipe 9, the second bucket elevator 5 conveys the material to the third conveying pipe 10, the third conveying pipe 10 introduces the material into the screening device 6, the screening device 6 screens the material, the material that meets the particle size requirements is sent to the inside of the ball mill 7 through the fourth conveying pipe 11 for grinding, and the material that does not meet the particle size requirements is recycled. It is sent to the roller press 4 again for extrusion and crushing, so as to avoid too much fine powder entering the roller press 4 and improve the operating stability of the roller press 4. Since the ball mill 7 is filled with fine powder, the ball mill 7 can be filled with small balls. When the ball loading is certain, the total number of steel balls increases, which improves the grinding effect of the steel balls on the materials and the hourly output of the ball mill 7. Due to the addition of the second bucket elevator 5 and the screening device 6, the materials crushed by the roller press 4 are sorted and milled, which improves the existing pre-grinding system in which the materials are directly fed into the mill after being extruded and sorted by the roller press, the particle size of the materials entering the mill is random and uncontrolled, and the process line is backward, thereby improving the energy efficiency index of the grinding system.

[0036] In this embodiment, the screening device 6 is connected to a first powder return pipe 12, and the first powder return pipe 12 is connected to the first conveying pipe 8. By setting the first powder return pipe 12, it is convenient to send the unqualified materials 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 stabilizing bin 3, and the roller press 4 extrude and crush this part of the material again.

[0037] In this embodiment, a three-way valve 13 is provided on the fourth conveying pipe 11, and the three-way valve 13 is connected to the second powder return pipe 14, and the second powder return pipe 14 is connected to the first conveying pipe 8. By adjusting the three-way valve 13, the flow direction of the qualified material after screening by the screening device 6 can be changed according to the use requirements.

[0038] In this embodiment, the cement grinding system also includes a dust collector 15, the input ends of the dust collector 15 are respectively connected to the conveying device 1, the first bucket elevator 2, the screening device 6 and the second bucket elevator 5. The dust collector 15 adopts an FMQD32-4 air box pulse bag dust collector to increase the dust collection air volume. The dust collector 15 is used to collect 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.

[0039] In this embodiment, the screening device 6 is a double-drum screen driven by a variable frequency motor. The double-drum screen can coarse and finely grade the material extruded by the roller press 4, and the coarse particle material returns to the steady flow bin 3 for repeated extrusion, thereby strictly controlling the particle size range of the material entering the ball mill 7.

[0040] In this embodiment, the conveying device 1 is a conveyor belt, which is easy to use, easy to maintain, and has low freight costs. It can also shorten the transportation distance, reduce the project cost, and save manpower and material resources.

[0041] In this embodiment, a weighing sensor level meter 16 is provided on the stabilizing bin 3, and the weighing sensor level meter 16 is used to monitor the material level of the stabilizing bin 3 to ensure that the roller press 4 can continuously and stably obtain the required materials, avoid production fluctuations caused by insufficient or excessive material supply, and facilitate timely adjustment of the feed amount according to the material level changes, optimize the production process, and improve production efficiency.

[0042] In this embodiment, an air lock valve 17 is provided at the connecting end of the fourth conveying pipe 11 and the ball mill 7, and an iron remover 18 is provided on the fourth conveying pipe 11. The air lock valve 17 is used to control the material entering the ball mill 7 and prevent gas backflow during the feeding process to maintain the stability of the internal environment of the ball mill 7. The iron remover 18 is used to continuously absorb iron impurities from the material, thereby protecting the ball mill 7 and improving the purity and performance of the product.

[0043] A cement grinding method comprises the following steps:

[0044] S1: using the conveying device 1 to convey the material to the feeding end of the first bucket elevator 2;

[0045] S2: the first bucket elevator 2 transports the material to the first conveying pipe 8, and the first conveying pipe 8 transports the material to the interior of the steady flow bin 3;

[0046] S3: the flow stabilizing bin 3 feeds materials into the roller press 4, the roller press 4 squeezes and crushes the materials, and the crushed materials are transported to the feeding end of the second bucket elevator 5 through the second conveying pipe 9;

[0047] 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 is used to screen the material, the material with a particle size 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 first powder return pipe 12, the first conveying pipe 8 conveys the material to the inside of the steady flow bin 3, so as to be squeezed for the second time by the roller press 4.

[0048] Distribution of the material left after milling, powder return from powder selector, finished product, and residual material from roller press:

[0049]

[0050] From the table above, it can be seen that after the roller press 4 extrudes, the material with a size of 80 μm accounts for 41.5%, and the material with a size of less than 3 mm accounts for 77%. After extrusion, the fine powder accounts for a large proportion and can be screened.

[0051] The comparison of main economic and technical indicators before and after the technical transformation is as follows:

[0052] Serial number project Current operating indicators Technical transformation goals Energy saving 1 Mill hourly output P.O42.5 (t / h) 155 170 Improve by 10% 2 Power consumption of grinding process (KWh / t) 26.5 ≤24.5 Down 7.5%

[0053] It can be seen from the above table that 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 and improves the effective work of the roller press 4 on the coarse particle return material. The output per unit is increased by more than 10% (about 15 tons) on the existing basis, and the power consumption is reduced by 1.5-2KWh / t.

[0054] In this embodiment, in S4, when the discharge volume of fine powder material is too large and the ball mill 7 cannot consume it completely, the three-way valve 13 is adjusted, and the second powder return pipe 14 is used to guide a part of the material into the steady flow bin 3, and the part of the material is screened and extruded multiple times. Under the premise of meeting the optimal working conditions of the ball mill 7, the material can be further reduced after being extruded by the roller press 4 multiple times to improve the grinding effect of the material, increase the hourly output, and reduce energy consumption.

[0055] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A cement grinding system, Features: It 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, and the first conveying pipe is used to convey materials to the interior of the flow stabilizing bin. The flow stabilizing bin is installed on the roller press. The lower end of the roller press is provided with a second conveying pipe, and the second conveying pipe is used to convey materials to the feed end of the second bucket elevator. The discharge end of the second bucket elevator is provided with a third conveying pipe, and the third conveying pipe is used to convey materials to the screening device. The lower end of the screening device is provided with a fourth conveying pipe, and the fourth conveying pipe is used to convey materials to the interior of the ball mill.

2. A cement grinding system according to claim 1, Features: The screening device is connected to a first powder return pipe, and the first powder return pipe is in communication with the first conveying pipe.

3. A cement grinding system according to claim 1, Features: The fourth conveying pipe is provided with a three-way valve, the three-way valve is connected to a second powder return pipe, and the second powder return pipe is communicated with the first conveying pipe.

4. A cement grinding system according to claim 1, Features: It also includes a dust collector, the input end of which is respectively connected to the conveying device, the first bucket elevator, the screening device and the second bucket elevator, 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.

5. A cement grinding system according to claim 1, Features: The screening device is a double-drum drum screen, which is driven by a variable frequency motor.

6. A cement grinding system according to claim 1, Features: The conveying device is a conveyor belt.

7. A cement grinding system according to claim 1, Features: A weighing sensor level meter is arranged on the steady flow bin.

8. A cement grinding system according to claim 1, Features: An air lock 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.

9. A cement grinding method, using the cement grinding system according to any one of claims 1 to 8, It is characterized in that The steps include: S1: using a conveying device to convey the material to the feeding end of the first bucket elevator; 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 steady flow bin; S3: The steady flow bin feeds materials into the roller press, and the roller press squeezes and crushes the materials. The crushed materials are transported to the feeding end of the second bucket elevator through the second conveying pipe; 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. The screening device is used to screen the material. The material with a particle size 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 first powder return pipe. The first conveying pipe conveys the material to the inside of the steady flow bin for secondary extrusion by the roller press.

10. A cement grinding method according to claim 9, Features: In S4, when the discharge volume of fine powder material is too large and the ball mill cannot consume it completely, the three-way valve is adjusted, and a part of the material is diverted into the steady flow bin by the second powder return pipe, and the part of the material is screened and extruded multiple times.

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