A ball mill direct discharge grinding classification system and classification process

Abstract

The application belongs to the technical field of mineral processing, and particularly discloses a ball-milling direct-discharging grinding and grading system and a grading process, which are used for grinding and grading of iron ore. The grinding and grading system comprises a ball mill, a cyclone separation cylinder, a thickening cylinder, a Z-shaped bucket elevator, a clean water pool and a magnetic separator. The cyclone separation cylinder comprises a separation cylinder feed inlet at the top end, a separation cylinder overflow outlet at the bottom end, a separation cylinder water inlet at the lower part of the side wall and a separation cylinder discharge outlet at the upper part of the side wall. The ball mill discharge outlet is directly above the separation cylinder feed inlet, the ball mill discharge outlet directly discharges into the cyclone separation cylinder through the separation cylinder feed inlet, the separation cylinder discharge outlet is connected with the thickening cylinder feed inlet, the separation cylinder overflow outlet is connected with the magnetic separator, the separation cylinder water inlet is connected with the clean water pool, the thickening cylinder discharge outlet is connected with the Z-shaped bucket elevator feed inlet, and the Z-shaped bucket elevator discharge outlet is connected with the ball mill feed inlet. The application cancels the slurry pump and the pump pool, and is beneficial to improving the system stability.

Description

Technical Field

[0001] This invention belongs to the field of iron ore beneficiation technology, and particularly relates to a ball mill direct-discharge grinding and classification system and classification process. Background Technology

[0002] Existing iron ore grinding and classification systems typically consist of ball mills, pump tanks, slurry pumps, and hydrocyclones. After crushing, the incoming ore enters the ball mill, where it is ground to a certain particle size and then discharged into the pump tank. There, it is mixed to a specific concentration and then pumped to the hydrocyclone for separation. The overflow fine-particle product from the hydrocyclone separation enters the subsequent magnetic separation process, while the coarse-particle underflow product is returned to the ball mill for regrinding. This process is simple and widely used.

[0003] However, due to the high density and hardness of iron ore, slurry pumps experience severe wear during production, with a typical service life of only 3 months. This significantly impacts normal continuous production and greatly increases equipment and maintenance costs. Because of the large size of the pump pool, slurry pumps can usually only pump slurry from a portion of the pool into the hydrocyclone for separation, leaving some low-velocity zones within the pump pool. Due to the high density and concentration of the incoming ore, these low-velocity zones experience significant particle settling and accumulation, which over time severely reduces the effective volume of the pump pool and affects the stable operation of the grinding and classification system. Summary of the Invention

[0004] One objective of this invention is to provide a ball mill direct discharge grinding and classification system that effectively solves the problems of severe wear of slurry pumps and particle deposition in the pump pool during existing grinding and classification processes.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A ball mill direct discharge grinding and classification system includes a ball mill, a cyclone separator, a thickener, a Z-type bucket elevator, a clear water tank, and a magnetic separator.

[0007] The ball mill includes a ball mill inlet and a ball mill outlet. The cyclone separator includes a separator feed inlet at the top, a separator overflow outlet at the bottom, a separator water inlet at the lower part of the side wall, and a separator discharge outlet at the upper part of the side wall. The separator water inlet is tangentially fed into the cyclone separator. The thickener includes a thickener inlet and a thickener discharge outlet.

[0008] The ball mill discharge port is located directly above the separator feed port. The ball mill discharge port directly enters the cyclone separator through the separator feed port. The separator discharge port is connected to the thickener feed port. The separator overflow port feeds the material into the magnetic separator. The separator water inlet is connected to the clear water tank through a clear water pump. The thickener discharge port feeds the material into the Z-type bucket elevator feed port. The Z-type bucket elevator discharges the material into the ball mill feed port.

[0009] Furthermore, the inner wall surrounding the thickening cylinder is provided with a screen for separating fine-grained materials and coarse-grained materials in the slurry.

[0010] The screen divides the internal space of the concentration cylinder into a fine-particle material receiving chamber and a coarse-particle material receiving chamber. The fine-particle material receiving chamber is the space between the screen and the inner wall of the concentration cylinder, and the fine-particle material receiving chamber is connected to the magnetic separator.

[0011] The bottom of the thickening cylinder is inverted conical, and the angle of the conical section of the thickening cylinder is less than 60°. The side wall of the lower part of the conical section of the thickening cylinder is provided with a thickening cylinder drain port for controlling the feeding of the fine-particle material into the magnetic separator.

[0012] The feed inlet of the concentration cylinder is located at the top of the concentration cylinder, and the discharge outlet of the concentration cylinder is located at the bottom of the concentration cylinder.

[0013] Furthermore, the concentration cylinder is equipped with a drain valve at its drain outlet for adjusting the discharge rate of fine-grained materials, and a discharge valve at its discharge outlet for adjusting the discharge rate of coarse-grained materials.

[0014] Furthermore, the discharge port of the concentration cylinder is located directly above the feed port of the Z-type bucket elevator.

[0015] Furthermore, the pump outlet of the water pump is connected to a first water supply pipeline and a second water supply pipeline. The first water supply pipeline connects the water inlet of the separation cylinder to the water tank, and the second water supply pipeline connects the feed inlet of the ball mill to the water tank. A water supply valve is provided on the second water supply pipeline.

[0016] Another objective of this invention is to provide a ball mill direct discharge grinding and classification process that effectively solves the problems of severe wear of slurry pumps and particle deposition in pump pools during existing grinding and classification processes.

[0017] A ball milling and classification process using a direct-displacement grinding system, applied to the ball milling and classification system described in the above embodiments, includes the following steps:

[0018] S1. High-concentration slurry is discharged from the ball mill discharge port. The high-concentration slurry enters the cyclone separator through the feed port of the separator. At the same time, water in the clear water tank is tangentially fed into the cyclone separator through the water feed port of the separator, and mixed with the high-concentration slurry to prepare a suitable separation concentration.

[0019] S2. The mixed slurry is separated by cyclone separation in the cyclone separator. The separated fine particles enter the magnetic separator for subsequent processing through the overflow port of the separator. The separated coarse particles enter the thickening cylinder through the discharge port of the separator. The discharge concentration of the coarse particles is adjusted by adjusting the drain valve and the discharge valve.

[0020] S3. After concentration adjustment, the coarse-grained material enters the Z-type bucket elevator through the discharge port of the thickening cylinder, and is then transported by the Z-type bucket elevator to the feed port of the ball mill, and returned to the ball mill for re-grinding.

[0021] Furthermore, the water in the clear water tank is tangentially fed into the cyclone separator at a certain speed and pressure by a clear water pump to provide separation energy.

[0022] The beneficial technical effects of this invention are:

[0023] (1) The present invention directly discharges material into the cyclone separator through the discharge port of the ball mill, eliminating the use of slurry pump and pump pool, and fundamentally solving the problem of severe wear of slurry pump and particle deposition in the existing grinding and classification process, which reduces the effective volume of the pump pool and affects the stable operation of the system.

[0024] (2) The present invention uses a water pump to tangentially feed clean water into the cyclone separator at a certain speed and pressure. The high-concentration discharge from the ball mill is mixed in the cyclone separator to prepare a slurry of appropriate concentration and complete the separation process of coarse and fine particles. There is no need to set up a pump tank, which is conducive to flexibly adjusting the slurry concentration in the cyclone separator, improving separation efficiency, saving costs, and improving system stability.

[0025] (3) By setting a screen inside the concentration cylinder, the present invention is conducive to filtering out fine particles and water, and improving the discharge concentration and discharge particle size.

[0026] (4) By designing a drain valve and a discharge valve on the concentration tank, the present invention facilitates flexible adjustment of the discharge concentration of the concentration tank.

[0027] (5) The present invention connects the second water supply pipeline of the clean water pump to the feed port of the ball mill and the clean water tank, and sets a water supply valve on the second water supply pipeline, which is beneficial to control the amount of clean water entering the ball mill through the water supply valve, thereby adjusting the grinding concentration of the ball mill. Attached Figure Description

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0029] Figure 1 This is a schematic diagram of the connection structure of the grinding and classification system of the present invention;

[0030] Figure 2 yes Figure 1 Schematic diagram of the structure of the cyclone separator;

[0031] Figure 3 yes Figure 1 Schematic diagram of the separation principle of a cyclone separator;

[0032] Figure 4 yes Figure 1 A cross-sectional view of the intermediate concentration chamber. Detailed Implementation

[0033] Example 1: A ball mill straight-flow grinding and classification system, such as Figure 1 As shown, the system includes a ball mill 1, a cyclone separator 2, a thickening cylinder 3, a Z-type bucket elevator 4, a clear water tank 5, and a magnetic separator 6. The ball mill 1 includes a ball mill inlet 11 and a ball mill outlet 12. Figure 2 As shown, the cyclone separator 2 includes a separator feed inlet 21 at the top, a separator overflow inlet 22 at the bottom, a separator water inlet 23 at the lower part of the side wall, and a separator discharge inlet 24 at the upper part of the side wall. The thickener 3 includes a thickener inlet 31 and a thickener discharge inlet 32. In this embodiment, the thickener inlet 31 is located at the top of the thickener 3, and the thickener discharge inlet 32 ​​is located at the bottom of the thickener 3 and is directly above the feed inlet of the Z-type bucket elevator 4. To facilitate discharge, the bottom of the thickener 3 is inverted conical, and the angle of the conical section of the thickener 3 is less than 60°.

[0034] The ball mill discharge port 12 is located directly above the separator feed port 21. The ball mill discharge port 12 discharges directly into the cyclone separator 2 through the separator feed port 21. The separator discharge port 24 is connected to the thickener feed port 31. The separator overflow port 22 discharges into the magnetic separator 6. The separator water inlet 23 is connected to the clear water tank 5 through the clear water pump 7. The thickener discharge port 32 discharges into the feed port of the Z-type bucket elevator 4. The Z-type bucket elevator 4 discharges into the ball mill feed port 11.

[0035] In this embodiment, the pump outlet of the clean water pump 7 is connected to a first water supply pipeline 71 and a second water supply pipeline 72. The first water supply pipeline 71 connects the water inlet 23 of the separator to the clean water tank 5, and the second water supply pipeline 72 connects the feed inlet 11 of the ball mill to the clean water tank 5. A water supply valve 721 is provided on the second water supply pipeline 72. By adjusting the water supply valve 721, the amount of clean water entering the ball mill 1 can be controlled, thereby adjusting the grinding concentration of the ball mill 1.

[0036] After being crushed, the ore enters the ball mill 1. Within the ball mill 1, the ore is ground to a certain particle size and then discharged through the ball mill discharge port 12. It then enters the cyclone separator 2 through the separator feed port 21. Simultaneously, water from the clear water tank 5 is pumped at a certain speed and pressure (0.1 MPa) through the first water supply pipeline 71 of the clear water pump 7 to the separator feed port 23, thus entering the cyclone separator 2 and providing separation energy. Based on actual production requirements, different concentrations of slurry are prepared by controlling the ore discharge rate at the ball mill discharge port 12 or the water flow rate through the first water supply pipeline 71 of the clear water pump 7.

[0037] The slurry undergoes hydrocyclone separation within the hydrocyclone separator 2, which is designed based on the hydrocyclone principle. The separation principle is as follows: Figure 3 As shown, fine and light particles (fine-grained materials) in the slurry spiral upward to form an inner vortex 8, which yields the overflow product. This overflow product is discharged through the overflow port 22 of the separator and fed into the magnetic separator 6. Coarse and heavy particles (coarse-grained materials) spiral downward to form an outer vortex 9, which yields the underflow product. This underflow product is transported through the discharge port 24 of the separator to the thickener 3.

[0038] Because the separation process in the cyclone separator 2 inevitably results in underflow entrainment, meaning that the slurry discharged through the discharge port 24 of the separator contains some fine-grained material, and since a 200-mesh sieve (75μm) is typically used as an evaluation index in iron ore production, particles smaller than 75μm (-200 mesh) can be directly subjected to magnetic separation. Therefore, if... Figure 4 As shown, a screen 10 for separating fine and coarse particles in the slurry is provided around the inner wall of the thickening cylinder 3. The screen aperture is selected as 200 mesh (separation particle size 75μm). The screen 10 divides the internal space of the thickening cylinder 3 into a fine particle material (particle size less than 75μm) receiving chamber A and a coarse particle material (particle size not less than 75μm) receiving chamber B. The fine particle material receiving chamber A is the space between the screen 10 and the inner wall of the thickening cylinder 3. The side wall of the lower part of the conical section of the thickening cylinder 3 is provided with a thickening cylinder drain outlet 33 for controlling the feeding of the fine particle material into the magnetic separator. The fine particle material receiving chamber A is connected to the magnetic separator 6 through the thickening cylinder drain outlet 33.

[0039] The slurry entering the thickener 3 is fed into the magnetic separator 6 through the screen 10, where fine particles and water are passed through the screen 10 and drained through the thickener 33. Since the slurry needs to reach a certain concentration before it can be returned to the ball mill 1 for further grinding, removing fine particles and water in the thickener 3 helps reduce the amount of returned sand and increases the concentration of the slurry returned to the ball mill 1.

[0040] To facilitate adjustment of the slurry concentration discharged from the thickener discharge port 32, a drain valve 331 for adjusting the discharge rate of fine-grained materials is provided at the thickener drain port 33, and a discharge valve 321 for adjusting the discharge rate of coarse-grained materials is provided at the thickener discharge port 32. By adjusting the opening and closing degree of the drain valve 331 and the discharge valve 321, the concentration of the slurry discharged from the thickener discharge port 32 is adjusted. A higher concentration of slurry discharged from the thickener discharge port 32 is more conducive to the conveying process of the Z-type bucket elevator 4.

[0041] Example 2: A ball mill direct discharge grinding and classification process, applied to the ball mill direct discharge grinding and classification system described in Example 1, includes the following steps: (1) High-concentration slurry is discharged from the ball mill discharge port 12. The high-concentration slurry enters the cyclone separator 2 through the separator feed port 21. At the same time, water in the clear water tank 5 is fed into the cyclone separator 2 tangentially through the separator feed port 23 at a certain speed and pressure via the first water supply pipeline 71 of the clear water pump 7 to mix with the slurry and provide separation pressure. (2) The slurry mixed with water is cyclone separated in the cyclone separator 2. The separated fine particles are fed into the magnetic separator 6 through the separator overflow port 22, and the separated coarse particles are fed into the thickener 3 through the separator discharge port 24 for concentration adjustment. (3) The coarse particles after concentration adjustment enter the Z-type bucket elevator 4 through the thickener discharge port 32 and are transported by the Z-type bucket elevator 4 to the ball mill feed port 11, and returned to the ball mill 1 for re-grinding.

[0042] This invention allows the ball mill discharge port to directly feed material into a cyclone separator for coarse and fine particle separation, eliminating the need for a slurry pump and pump tank. This fundamentally solves the problems of severe wear on the slurry pump and particle deposition in the pump tank during existing grinding and classification processes, which reduces the effective volume of the pump tank and affects the stable operation of the system.

[0043] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A ball mill direct-displacement grinding and classification system, characterized in that, Includes ball mills, hydrocyclones, thickeners, Z-type bucket elevators, clear water tanks, and magnetic separators; The ball mill includes a ball mill inlet and a ball mill outlet. The cyclone separator includes a separator feed inlet at the top, a separator overflow inlet at the bottom, a separator water inlet at the lower part of the side wall, and a separator discharge inlet at the upper part of the side wall. The separator water inlet is tangentially fed into the cyclone separator. The thickener includes a thickener inlet and a thickener discharge inlet. The ball mill discharge port is located directly above the separator feed port. The ball mill discharge port directly enters the cyclone separator through the separator feed port. The separator discharge port is connected to the thickener feed port. The separator overflow port feeds the material into the magnetic separator. The separator water inlet is connected to the clear water tank through a clear water pump. The thickener discharge port feeds the material into the Z-type bucket elevator feed port. The Z-type bucket elevator discharges the material into the ball mill feed port. The inner wall of the thickening cylinder is equipped with a screen for separating fine and coarse particles in the slurry. The screen divides the internal space of the concentration cylinder into a fine-particle material receiving chamber and a coarse-particle material receiving chamber. The fine-particle material receiving chamber is the space between the screen and the inner wall of the concentration cylinder. The fine-particle material receiving chamber is connected to the magnetic separator. The bottom of the thickening cylinder is inverted conical, the angle of the conical section of the thickening cylinder is less than 60°, and the side wall of the lower part of the conical section of the thickening cylinder is provided with a thickening cylinder drain port for controlling the feeding of the fine-particle material into the magnetic separator. The feed inlet of the concentration cylinder is located at the top of the concentration cylinder, and the discharge outlet of the concentration cylinder is located at the bottom of the concentration cylinder.

2. The ball mill direct-discharge grinding and classification system according to claim 1, characterized in that, The concentration cylinder is equipped with a drain valve at its drain outlet for adjusting the discharge rate of fine-grained materials, and a discharge valve at its discharge outlet for adjusting the discharge rate of coarse-grained materials.

3. The ball mill straight-displacement grinding and classification system according to claim 2, characterized in that, The discharge port of the thickening cylinder is located directly above the feed port of the Z-type bucket elevator.

4. The ball mill straight-discharge grinding and classification system according to claim 3, characterized in that, The outlet of the water pump is connected to a first water supply pipeline and a second water supply pipeline. The first water supply pipeline connects the water inlet of the separator to the water tank, and the second water supply pipeline connects the feed inlet of the ball mill to the water tank. A water supply valve is provided on the second water supply pipeline.

5. A ball milling and classification process with direct discharge, characterized in that, The grinding and classification system applied to the ball mill direct-discharge system according to any one of claims 1-4 includes the following steps: S1. High-concentration slurry is discharged from the ball mill discharge port. The high-concentration slurry enters the cyclone separator through the feed port of the separator. At the same time, water in the clear water tank is tangentially fed into the cyclone separator through the water feed port of the separator to mix with the high-concentration slurry. S2. The mixed slurry is separated by cyclone separation in the cyclone separator. The fine particles after separation enter the magnetic separator through the overflow port of the separator for subsequent processing, while the coarse particles after separation enter the thickener through the discharge port of the separator for concentration adjustment. S3. After concentration adjustment, the coarse-grained material enters the Z-type bucket elevator through the discharge port of the thickening cylinder, and is then transported by the Z-type bucket elevator to the feed port of the ball mill, and returned to the ball mill for re-grinding.

6. The ball milling and classification process according to claim 5, characterized in that, The water in the clear water tank is pumped tangentially into the cyclone separator at a certain speed and pressure by a clear water pump to provide separation energy.

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