An apparatus for changing the particle size distribution of a mill

Abstract

This invention discloses a device for changing the particle size distribution of a mill, relating to the field of mill equipment technology. By employing a segmented wet mill, the raw material input from the first raw coal bunker is first ground and slurried sequentially through the rod mill section and the ball mill section to generate an ultrafine coal slurry, which is then output to a fine slurry tank. Then, the raw material input from the second raw coal bunker, the ultrafine coal slurry from the fine slurry tank, and the raw material are mixed and ground together in a second mill. The resulting coal slurry with a predetermined particle size is output to the discharge trough. This method can obtain a high-concentration, fine-particle coal slurry, while also adjusting the particle size distribution. It features high grinding efficiency, high grinding quality, optimized particle size distribution, improved product quality, and a simple structure.

Description

Technical Field

[0001] This invention relates to the field of mill equipment technology, and in particular to a device for changing the particle size distribution of a mill. Background Technology

[0002] In coal processing, coal chemical industry, and other mining and chemical industries, mills are key equipment for preparing coal slurry, used in processes such as grinding and slurry preparation in the fine processing of minerals.

[0003] However, rod mills and ball mills have lacked particle size adjustment mechanisms for many years, resulting in a normal particle size distribution with more particles in the center and fewer at the edges. From a packing theory perspective, this normal distribution contradicts the high-density packing theory (which requires more particles at the edges and fewer in the center). Consequently, their slurry concentration has been inherently limited and cannot be increased. Particle size distribution directly affects slurry concentration and subsequent processing costs. Low concentration leads to easy sedimentation, increased equipment wear, and requires bulky subsequent processing units that necessitate separate treatment of excess wastewater.

[0004] Therefore, developing a mill with a compact structure, high grinding efficiency, and the ability to optimize particle size distribution is one of the key tasks for those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a device for changing the particle size distribution of a mill, thereby increasing the pulp concentration and particle distribution by producing ultrafine particles and increasing the means of adjusting the particle size distribution of the mill.

[0006] To address the aforementioned technical problems, this invention provides a device for changing the particle size distribution of a mill, comprising a segmented wet mill, a second mill, and a particle size controller. The particle size controller is connected to the segmented wet mill and the second mill and is used to control the operating status of the segmented wet mill and the second mill. The segmented wet mill includes a rod mill section and a ball mill section arranged sequentially from the feed inlet to the discharge outlet. It is used to grind and slurry the raw materials input from the first raw coal bunker through the rod mill section and the ball mill section, and then generate ultrafine coal slurry through an ultrafine screen set at the discharge outlet, and output it to the fine slurry tank. A screen plate for material screening is provided between the rod mill section and the ball mill section. The second mill is connected to the second raw coal bunker and the fine slurry tank and is used to mix and grind the input ultrafine coal slurry and raw materials to form a slurry, and output the generated coal slurry of a predetermined particle size to the discharge tank.

[0007] It also includes a first particle size distribution detector installed in the segmented wet mill and a second particle size distribution detector installed in the second mill. The first particle size distribution detector is used to detect the concentration of ultrafine coal slurry and the slurry concentration of the second mill. The first particle size distribution detector and the second particle size distribution detector are connected to a particle size controller. The particle size controller is used to control the operating status of the segmented wet mill and the second mill according to the concentration of ultrafine coal slurry and the slurry concentration of the second mill.

[0008] It also includes a display connected to particle size control, used to display the concentration of ultrafine coal slurry, the slurry concentration of the second mill, and the operating status data of the segmented wet mill and the second mill.

[0009] Among them, the ultrafine screen is a 200~600 mesh ultrafine screen.

[0010] The rod mill section is filled with steel rod grinding media, while the ball mill section is filled with steel ball grinding media. The length ratio of the rod mill section to the ball mill section is 1:1-2:3. The diameter of the steel rods in the steel rod grinding media is 50-80mm. The difference between the length of the chamber and the length of the steel rods in the rod mill section is 50-100mm. The diameter of the steel balls in the steel ball grinding media is 45-70mm. The filling rate of the steel rods in the rod mill section is 30%-45%, and the filling rate of the steel balls in the ball mill section is 40%-50%.

[0011] The ball mill section structure includes a first ball mill unit and a second ball mill unit, as well as an isolation sieve plate for separating the first ball mill unit and the second ball mill unit. The diameter of the steel ball grinding media in the first ball mill unit is 40-50 mm, and the diameter of the steel ball grinding media in the second ball mill unit is 20-30 mm. The first ball mill unit is located between the second ball mill unit and the sieve plate.

[0012] The sieve plate has a sieve hole diameter of 2.5-5mm.

[0013] It also includes a first wear-resistant liner plate disposed on the inner wall of the rod mill section structure, a second wear-resistant liner plate disposed on the inner wall of the ball mill section structure, and an axial groove disposed on the surface of the first wear-resistant liner plate. The axial groove is used to limit the steel rod grinding media of the rod mill section structure.

[0014] This also includes a corrugated structure set on the surface of the second wear-resistant liner.

[0015] The system also includes a drive mechanism installed in the segmented wet mill. The drive mechanism includes a drive motor, a main reducer, a pneumatic clutch air compressor, a gear drive component, and a gear spray lubrication unit. The drive motor is connected to the gear drive component and is used to drive the drum to rotate through the meshing of the gear drive component with the gears on the outer wall of the drum. The main reducer is located between the drive motor and the gear drive component and is used to change the speed output from the drive motor to the gear drive component. The pneumatic clutch air compressor is used to open or close the transmission connection between the drive motor and the gear drive component. The gear spray lubrication unit is used to spray lubricant for the meshing of the gear drive component with the drum.

[0016] The segmented wet mill for coal slurry preparation provided in this invention has the following advantages compared with the prior art:

[0017] The segmented wet mill for coal slurry preparation provided in this invention first grinds the raw materials input from the first raw coal bunker through a rod mill section and a ball mill section to generate an ultrafine coal slurry, which is then output to a fine slurry tank. Then, a second mill mixes and grinds the raw materials input from the second raw coal bunker and the ultrafine coal slurry from the fine slurry tank, producing a coal slurry of a predetermined particle size, which is then output to a discharge trough. This method yields a high-concentration, fine-particle coal slurry, while also allowing for adjustment of particle size distribution, improving product quality. The structure is simple, resulting in a more reasonable particle size distribution in the final product, increased grinding efficiency, and higher coal slurry concentration. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of a structure in one embodiment of the device for changing the particle size distribution of a mill provided by the present invention;

[0020] Figure 2 A front structural schematic diagram of an embodiment of the segmented wet mill for coal slurry preparation provided by the present invention;

[0021] Among them, 1-roller, 11-bar mill section structure, 12-ball mill section structure, 111-steel rod grinding media, 121-steel ball grinding media, 6-sieve plate, 7-feed inlet, 8-discharge outlet, 9-drive device, 91-drive motor, 92-main reducer, 93-pneumatic clutch air compressor, 94-gear spray lubrication unit, 100-segmented wet mill, 200-particle size controller, 300-second mill, 400-fine slurry tank, 500-second raw coal bunker, 600-discharge chute, 700-first raw coal bunker. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please refer to Figures 1-2 , Figure 1A schematic diagram of a structure in one embodiment of the device for changing the particle size distribution of a mill provided by the present invention; Figure 2 A front view of a segmented wet mill in one embodiment of the device for changing the particle size distribution of a mill provided by the present invention.

[0024] In one specific embodiment, the device for changing the particle size distribution of a mill includes a segmented wet mill 100, a second mill 300, and a particle size controller 200. The particle size controller 200 is connected to the segmented wet mill 100 and the second mill 300 and is used to control the operating status of the segmented wet mill 100 and the second mill 300. The segmented wet mill 100 includes a rod mill section and a ball mill section arranged sequentially from the feed inlet to the discharge outlet, used to process the first raw material... The raw materials input into the coal bunker 700 are successively ground and slurried through the rod mill section and the ball mill section, and then generated into ultrafine coal slurry through the ultrafine screen set at the discharge port, and output to the fine slurry tank 400. A screen plate for material screening is set between the rod mill section and the ball mill section. The second mill 300 is connected to the second raw coal bunker 500 and the fine slurry tank 400, and is used to mix and grind the input ultrafine coal slurry and raw materials to form a slurry, and output the coal slurry of the predetermined particle size to the discharge tank 600.

[0025] By employing a segmented wet mill 100, the raw materials input from the first raw coal bunker 700 are first ground and slurried sequentially through a rod mill section and a ball mill section to generate an ultrafine coal slurry, which is then output to the fine slurry tank 400. Then, the raw materials input from the second raw coal bunker 500 and the ultrafine coal slurry input from the fine slurry tank 400 are mixed and ground together in the second mill 300 to produce a coal slurry of a predetermined particle size, which is then output to the discharge tank 600. This process can obtain a high-concentration, fine-particle coal slurry, while also adjusting the particle size distribution and improving product quality. The structure is simple, resulting in a more reasonable particle size distribution of the final product, improved grinding efficiency, and increased coal slurry concentration.

[0026] To further optimize the particle size distribution of the final product and ensure product quality stability, in one embodiment, the device for changing the mill particle size distribution further includes a first particle size distribution detector installed in the segmented wet mill 100 and a second particle size distribution detector installed in the second mill 300. The first particle size distribution detector is used to detect the concentration of the ultrafine coal slurry and the slurry concentration of the second mill 300. The first particle size distribution detector and the second particle size distribution detector are connected to a particle size controller 200. The particle size controller 200 is used to control the operating status of the segmented wet mill 100 and the second mill 300 according to the concentration of the ultrafine coal slurry and the slurry concentration of the second mill 300.

[0027] By setting a first particle size distribution detector in the segmented wet mill 100 and a second particle size distribution detector in the second mill 300, the concentration of the generated ultrafine coal slurry and the slurry concentration of the second mill 300 are detected and fed back to the particle size controller 200. The controller then controls the operating status of the segmented wet mill 100 and the second mill 300, optimizes the operating parameters, and ensures that the obtained product particle size meets the requirements. For example, the grinding time, grinding power, raw material input, and coal slurry output can be monitored and controlled to achieve flexibility and stability in product preparation.

[0028] This application does not limit the structure, type, or distribution location of the first particle size distribution detector and the second particle size distribution detector. Particle size distribution detection can be performed using physical or chemical means, including but not limited to conductivity and transmittance.

[0029] To improve management efficiency, in one embodiment, the device for changing the mill particle size distribution further includes a display connected to the particle size control, for displaying the concentration of the ultrafine coal slurry, the slurry concentration of the second mill 300, and the operating status data of the segmented wet mill 100 and the second mill 300.

[0030] By setting up a display to show the device's operating and control parameters, the device's status can be clearly seen, improving control efficiency.

[0031] This application does not limit the type of display or the display method.

[0032] In addition, communication modules such as wireless communication modules can be used for remote data acquisition and remote control.

[0033] This application uses an ultrafine screen to filter coal slurry, ensuring the output coal slurry particle size range. There are no restrictions on the type, material, installation method, or mesh size of the ultrafine screen. The ultrafine screen is a 200~600 mesh screen.

[0034] The segmented wet mill 100 in this application performs rod milling and ball milling on the incoming raw materials by setting up rod milling section structure and ball milling section structure. There are no limitations on the structure, material and size of the rod milling section structure and ball milling section structure.

[0035] In one embodiment, the rod mill section is filled with steel rod grinding media, and the ball mill section is filled with steel ball grinding media. The length ratio of the rod mill section to the ball mill section is 1:1-2:3. The diameter of the steel rods in the steel rod grinding media is 50-80mm. The difference between the length of the chamber and the length of the steel rods in the rod mill section is 50-100mm. The diameter of the steel balls in the steel ball grinding media is 45-70mm. The filling rate of the steel rods in the rod mill section is 30%-45%, and the filling rate of the steel balls in the ball mill section is 40%-50%.

[0036] By adopting a method of first grinding with rods and then grinding with balls, the particle size of the material is reduced to a certain extent before the ball mill section is used for fine grinding. This can reduce the damage to the ball grinding media of the ball mill section and improve the overall operational reliability and service life.

[0037] In this application, the lengths of the rod mill section structure 11 and the ball mill section structure 12 are not limited and can be set as needed.

[0038] In this application, since both the rod grinding section structure 11 and the ball grinding section structure 12 are set up simultaneously, the rod grinding is used for preliminary grinding and the ball grinding is used for deep grinding. Therefore, the size of the steel rod does not need to be too large, and the overall size can also be reduced. This can reduce the bending and entanglement of the grinding rod, extend the service life of the grinding rod, and reduce the equipment maintenance cost.

[0039] This application does not limit the size of the rod grinding section structure 11, nor does it limit the filling rate of the steel rods in the rod grinding section structure 11 or the filling rate of the steel balls in the ball grinding section structure 12.

[0040] By employing both rod mill section structure 11 and ball mill section structure 12, the filling rate of steel rods can be reduced, thus reducing energy consumption.

[0041] To further improve the grinding effect and grinding quality, in one embodiment, the ball mill section structure includes a first ball mill unit and a second ball mill unit, as well as an isolation sieve plate for separating the first ball mill unit and the second ball mill unit. The diameter of the steel ball grinding media in the first ball mill unit is 40-50 mm, and the diameter of the steel ball grinding media in the second ball mill unit is 20-30 mm. The first ball mill unit is located between the second ball mill unit and the sieve plate.

[0042] By designing the ball mill section structure as a first ball mill unit and a second ball mill unit, and separating them with an isolation sieve plate 6, a larger size steel ball grinding media 121 can be used for preliminary grinding, while a smaller size steel ball grinding media 121 can be used for fine grinding, thereby improving the efficiency and quality of grinding.

[0043] This application does not limit the size and filling rate of the steel ball grinding media 121 in the first and second ball milling units.

[0044] Because the sidewall of the roller 1 is frequently struck during the grinding process, it is easy to damage the bronze and generate a lot of noise. In order to solve this technical problem, in one embodiment, the segmented wet mill 100 for coal slurry preparation also includes a first wear-resistant liner plate disposed on the inner wall of the rod mill section structure 11 and a second wear-resistant liner plate disposed on the inner wall of the ball mill section structure 12.

[0045] By providing a first wear-resistant liner on the inner wall of the rod mill section structure 11 and a second wear-resistant liner on the inner wall of the ball mill section structure 12, the damage of the grinding media to the side wall of the drum 1 during the grinding process can be reduced, thereby improving the service life of the equipment.

[0046] This application does not limit the material, thickness, or installation method of the first and second wear-resistant liners. They can be installed by means of snap-fit ​​or bolt connection, which makes it easy to replace them and improves maintenance efficiency.

[0047] Furthermore, in order to facilitate the restriction of the steel bar grinding media 111, reduce its movement, and improve the reliability of grinding, in one embodiment, the device for changing the mill particle size distribution further includes an axial groove provided on the surface of the first wear-resistant liner for limiting the steel bar grinding media of the bar grinding section structure 11.

[0048] By providing an axial groove on the surface of the first wear-resistant liner, the steel rod grinding media 111 of the rod grinding section structure 11 is limited, so that after the steel rod grinding media 111 is installed, only the working part is exposed and the installation part is not exposed, thus improving the reliability of use.

[0049] To further reduce the material running speed, reduce the impact on the equipment and reduce the occurrence of splashing, and improve the reliability of grinding, in one embodiment, the device for changing the mill particle size distribution also includes a corrugated structure disposed on the surface of the second wear-resistant liner.

[0050] By setting a corrugated structure on the surface of the second wear-resistant liner, material splashing can be prevented during the grinding process. This avoids the reduction of material in some areas due to excessive particle movement distance after grinding, which would reduce grinding efficiency. Instead, the material is concentrated as much as possible to enhance the grinding effect and thus improve grinding efficiency.

[0051] This application does not limit the shape or size of the wave-shaped structure.

[0052] In this application, the rod mill section structure 11 and the ball mill section structure 12 are isolated by a sieve plate, thereby effectively controlling the particle size of the material entering the ball mill section and avoiding excessive grinding caused by overly coarse particles entering the ball mill section. In one embodiment, the sieve hole diameter of the sieve plate 6 is 2.5-5mm.

[0053] This application does not limit the shape, size, or distribution of the sieve holes in the sieve plate 6, nor does it limit the size, material, or installation method of the sieve plate. It can be designed according to actual grinding needs.

[0054] In this application, the segmented wet mill 100 is generally equipped with a drum 1, a drive device 9, and a feeding and discharging device. The rod mill section structure and the ball mill section structure are set inside the drum 1. They can be set horizontally, vertically, or in other ways. The drum 1 is driven to rotate by the drive device 9.

[0055] The structure and driving method of the drive device 9 are not limited. In one embodiment, the drive device 9 includes a drive motor 91, a main reducer 92, a pneumatic clutch air compressor 93, a gear drive component, and a gear spray lubrication unit 94. The drive motor 91 is connected to the gear drive component and is used to drive the roller 1 to rotate through the meshing of the gear drive component with the gear on the outer wall of the roller 1. The main reducer 92 is disposed between the drive motor 91 and the gear drive component and is used to change the speed output from the drive motor 91 to the gear drive component. The pneumatic clutch air compressor 93 is used to open or close the transmission connection between the drive motor 91 and the gear drive component. The gear spray lubrication unit 94 is used to spray lubricant for the meshing of the gear drive component with the roller 1.

[0056] By using a main reducer 92 connected to a gear drive, the speed of the gear drive and the speed of the drum 1 can be controlled. The drive connection between the two can be disconnected or closed by a pneumatic clutch air compressor 93, improving the safety and reliability of use. The reliability of driving the drum 1 is ensured by using gear meshing.

[0057] The gear spray lubrication unit 94 sprays lubricant to ensure the reliable meshing of the gears between the gear drive component and the roller 1.

[0058] In one embodiment, a segmented wet mill 100 includes a horizontally arranged drum 1, a drive unit 9, and a feeding and discharging device. The drum 1 is internally divided into two sections along the axial direction: a front section is a rod mill section, and a rear section is a ball mill section. The rod mill section is filled with steel rods as grinding media, and the ball mill section is filled with steel balls as grinding media. The length of the steel rods is 2 / 3 of the length of grinding rods in wet mills of the same specifications in the prior art. The specifications of the steel balls are consistent with those commonly used in the market. The length ratio of the rod mill section to the ball mill section is 1:1 to 2:3. The diameter of the steel rods is 50-80 mm, and the length is 50-100 mm shorter than the length of the rod mill section. The length of the steel rods is 4-3 meters. The diameter of the steel balls is 45-70 mm. The steel rod filling rate of the rod mill section is 30%-45%, and the steel ball filling rate of the ball mill section is 40%-50%.

[0059] The inner wall of the drum 1 is equipped with a wear-resistant liner, and the surface of the liner in the bar grinding section is provided with an axial groove to reduce the lateral movement of the steel rod; the liner in the ball grinding section adopts a wave-shaped structure to enhance the grinding effect of the steel ball.

[0060] A sieve plate is installed between the rod mill section and the ball mill section. The sieve hole diameter on the sieve plate is 2.5-5mm, which is used to control the particle size of the material entering the ball mill section.

[0061] The working process of the above device is as follows:

[0062] Raw coal and water are mixed in a certain proportion and enter the rod mill section of drum 1. Inside the rod mill section, the length of the steel rods is shortened to 2 / 3 of the traditional length, reducing entanglement and bending between the rods and improving grinding efficiency. Line contact is formed between the steel rods, selectively crushing coarse coal particles to a preliminary size of 3-5 mm or less. The pre-ground material passes through a screen plate into the ball mill section. Inside the ball mill section, steel balls of different sizes further grind the material, refining some of the qualified coal particles to obtain a coal slurry with a reasonable particle size distribution, which is then discharged from the ball mill section outlet.

[0063] The segmented grinding design employs a rod mill section for initial grinding of coal particles and limiting them to the ideal particle size, while a ball mill section performs fine grinding, resulting in a more reasonable particle size distribution in the final product. Experimental data shows that the coal slurry concentration can be increased by 2-8%.

[0064] The length of the grinding rod is shortened to two-thirds of the traditional length, reducing bending and tangling, extending the lifespan of the grinding rod, and lowering equipment maintenance costs. The rod mill section uses a lower filling rate (30%-45%), reducing energy consumption by approximately 5-10% compared to traditional ball mills.

[0065] Compared to the traditional series process of rod mills and ball mills, the integrated structural design reduces the equipment footprint and minimizes material transfer losses. A sieve plate is installed between the rod mill section and the ball mill section to effectively control the particle size of the material entering the ball mill section, preventing excessively coarse particles from entering and causing over-grinding.

[0066] In one embodiment, the segmented wet mill 100 has a drum 1 with a total length of 6m and a diameter of 2.4m. The drum 1 is internally divided into two sections along the axial direction: the front section is a rod mill section with a length of 2.7m; the rear section is a ball mill section with a length of 3.3m. A sieve plate with a sieve aperture of 4mm is provided between the rod mill section and the ball mill section.

[0067] The bar mill section is filled with steel bars of 60mm, 70mm and 80mm in diameter, with each diameter accounting for 1 / 3 of the total length. The length of the steel bars is 1.8m (the length of the grinding bars in existing mills of the same specifications is usually 2.7m, and in this embodiment it is 2 / 3 of the length). The steel bar filling rate is 22%.

[0068] The inner wall of the rod mill section roller 1 is provided with a wear-resistant rubber liner with axial grooves to reduce the lateral movement of the steel rod.

[0069] The ball mill section is filled with steel balls. The front half near the sieve plate is filled with steel balls with a diameter of 40-50 mm, and the rear half is filled with steel balls with a diameter of 20-30 mm, with a steel ball filling rate of 45%. The inner wall of the ball mill section roller 1 is equipped with a corrugated wear-resistant liner to enhance the grinding effect.

[0070] During operation, raw coal and water are mixed at a mass ratio of 1:1.2 and continuously fed into the rod mill section. Under the rotation of roller 1, the steel rods in the rod mill section initially grind the coal, breaking the coal particles to below 4mm. Qualified material passes through the screen plate and enters the ball mill section, where it is further refined under the grinding action of the steel balls, ultimately obtaining a coal slurry with a reasonable particle size distribution. Experimental data show that using the wet mill of this application, the coal slurry concentration can reach 70-73%, which is 6-8% higher than that of a traditional single ball mill, and the proportion of ultrafine particles below -10μm is reduced by 12%, effectively reducing over-grinding.

[0071] The device for changing the particle size distribution of a mill in this application aims to obtain a high-concentration slurry. The core issue is to address the high-density packing of particles, as only high-density packing can achieve high concentration. This is achieved by "increasing the particle size distribution," specifically by increasing the amount of ultrafine particles in a rod mill or ball mill, thereby increasing the adjustment means of the slurry preparation equipment and changing the original particle size distribution to increase the concentration.

[0072] The specific principle is as follows: the raw material is processed into 200-600 mesh ultrafine particles through a segmented wet mill 100, with a coal slurry concentration of 40-45%. Then, it is pumped into the cylinder of a rod mill or ball mill and mixed rapidly with the slurry of the rod mill or ball mill. The mixture is then overflowed through an overflow weir and finally filtered through a drum screen to obtain the final slurry product.

[0073] In this application, ultrafine coal slurry is obtained by filtration through an ultrafine screen, with the screen opening controlled between 200 and 600 mesh, and the average particle size around 325 mesh.

[0074] Different rod mills and ball mills have different designs, residence times, rotation speeds, rod feed rates, and ball feed rates, resulting in different coarse and fine particle contents in the pulp. Therefore, the bulk density is related to the ratio of coarse to fine particles in the equipment, and the produced ultrafine particles need to be adjustable.

[0075] Ultrafine particles can also be obtained using ultrafine sieves of other mesh sizes, such as 200 mesh, 250 mesh, 300 mesh, 350 mesh, and 400 mesh ultrafine sieves.

[0076] This application does not limit the type of the second mill 300, which can be a rod mill, a ball mill, or a combination thereof. The proportion of the input ultrafine coal slurry and raw materials is not limited and is generally set according to actual needs. Generally, the mass percentage of ultrafine particles in ultrafine coal slurry is 15-30% of the total slurry volume.

[0077] Compared with existing technical solutions, the above-mentioned device has the following advantages:

[0078] 1. The addition of 100 segmented wet mills can increase the coal slurry preparation system's processing capacity by more than 70%.

[0079] 2. After adding a segmented wet mill 100, the particle size distribution measurement system is used to adjust the mill according to different coal types.

[0080] 3. With the addition of 100 segmented wet mills, intelligent control and unmanned operation of the entire production process can be achieved through an online concentration meter measurement system.

[0081] 4. The addition of a segmented wet mill 100 changes the slurry gradation relationship, which can increase the coal slurry concentration and improve gasification efficiency. For example, in one embodiment, the effective gas can be increased by 1 to 1.5 percentage points, and the output can be increased by 5 to 6%, which is conducive to energy conservation, emission reduction and green transformation of the coal chemical industry.

[0082] In summary, the device for changing the particle size distribution of a mill provided in this embodiment of the invention first uses a segmented wet mill to grind and slurry the raw material input from the first raw coal bunker through the rod mill section and the ball mill section, generating an ultrafine coal slurry, which is then output to the fine slurry tank. Then, the second mill mixes and grinds the raw material input from the second raw coal bunker, the ultrafine coal slurry from the fine slurry tank, and the raw material, producing a coal slurry of a predetermined particle size, which is then output to the discharge trough. This method can obtain a high-concentration, fine-particle coal slurry, while also adjusting the particle size distribution, improving product quality, and has a simple structure. It results in a more reasonable particle size distribution of the final product, improves grinding efficiency, and increases coal slurry concentration.

[0083] The apparatus for changing the particle size distribution of a mill provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core idea of ​​the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principle of the invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A device for changing the particle size distribution of a mill, characterized in that, The system includes a segmented wet mill, a second mill, and a particle size controller. The particle size controller is connected to the segmented wet mill and the second mill and is used to control the operating status of the segmented wet mill and the second mill. The segmented wet mill includes a rod mill section and a ball mill section arranged sequentially from the feed inlet to the discharge outlet. It is used to grind and slurry the raw materials input from the first raw coal bunker through the rod mill section and the ball mill section, and then generate ultrafine coal slurry through an ultrafine screen set at the discharge outlet, and output it to the fine slurry tank. A screen plate for material screening is set between the rod mill section and the ball mill section. The second mill is connected to the second raw coal bunker and the fine slurry tank and is used to mix and grind the input ultrafine coal slurry and raw materials to form a pulp, and output the generated coal slurry of a predetermined particle size to the discharge trough.

2. The device for changing the particle size distribution of a mill as described in claim 1, characterized in that, It also includes a first particle size distribution detector installed in the segmented wet mill and a second particle size distribution detector installed in the second mill. The first particle size distribution detector is used to detect the concentration of the ultrafine coal slurry and the slurry concentration of the second mill. The first particle size distribution detector and the second particle size distribution detector are connected to the particle size controller. The particle size controller is used to control the operating status of the segmented wet mill and the second mill according to the concentration of the ultrafine coal slurry and the slurry concentration of the second mill.

3. The device for changing the particle size distribution of a mill as described in claim 2, characterized in that, It also includes a display connected to the particle size control, used to display the concentration of the ultrafine coal slurry, the slurry concentration of the second mill, and the operating status data of the segmented wet mill and the second mill.

4. The device for changing the particle size distribution of a mill as described in claim 1, characterized in that, The ultrafine screen is a 200-600 mesh ultrafine screen.

5. The apparatus for changing the particle size distribution of a mill as described in claim 1, characterized in that, The rod milling section is filled with steel rod grinding media, and the ball milling section is filled with steel ball grinding media. The length ratio of the rod milling section to the ball milling section is 1:1-2:

3. The diameter of the steel rods in the steel rod grinding media is 50-80mm. The difference between the length of the chamber and the length of the steel rods in the rod milling section is 50-100mm. The diameter of the steel balls in the steel ball grinding media is 45-70mm. The filling rate of the steel rods in the rod milling section is 30%-45%, and the filling rate of the steel balls in the ball milling section is 40%-50%.

6. The apparatus for changing the particle size distribution of a mill as described in claim 4, characterized in that, The ball mill section structure includes a first ball mill unit and a second ball mill unit, as well as an isolation sieve plate for separating the first ball mill unit and the second ball mill unit. The diameter of the steel ball grinding media in the first ball mill unit is 40-50 mm, and the diameter of the steel ball grinding media in the second ball mill unit is 20-30 mm. The first ball mill unit is located between the second ball mill unit and the sieve plate.

7. The apparatus for changing the particle size distribution of a mill as described in claim 6, characterized in that, The sieve plate has a sieve hole diameter of 2.5-5mm.

8. The apparatus for changing the particle size distribution of a mill as described in claim 6, characterized in that, It also includes a first wear-resistant liner plate disposed on the inner wall of the rod mill section structure, a second wear-resistant liner plate disposed on the inner wall of the ball mill section structure, and an axial groove disposed on the surface of the first wear-resistant liner plate, the axial groove being used to limit the steel rod grinding media of the rod mill section structure.

9. The apparatus for changing the particle size distribution of a mill as described in claim 8, characterized in that, It also includes a corrugated structure disposed on the surface of the second wear-resistant liner.

10. The apparatus for changing the particle size distribution of a mill as described in claim 1, characterized in that, The system also includes a drive mechanism disposed in the segmented wet mill. The drive mechanism includes a drive motor, a main reducer, a pneumatic clutch air compressor, a gear drive component, and a gear spray lubrication unit. The drive motor is connected to the gear drive component and is used to drive the drum to rotate through the meshing of the gear drive component with the gear on the outer wall of the drum. The main reducer is disposed between the drive motor and the gear drive component and is used to change the speed output from the drive motor to the gear drive component. The pneumatic clutch air compressor is used to open or close the transmission connection between the drive motor and the gear drive component. The gear spray lubrication unit is used to spray lubricant for the meshing of the gear drive component with the drum.

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