Design method for reducing overgrinding of material in a mining roll mill

Abstract

This invention discloses a design method for reducing over-grinding of materials in a mining roller mill, belonging to the field of ore crushing and grinding. The method includes the following steps: S1. Based on the mill's design time and the material's grindability, determine the grinding disc diameter Dt, the large end diameter Dr1 of the grinding roller, the small end diameter Dr2 of the grinding roller, and the grinding roller width Br according to conventional mill selection design methods; S2. Calculate the feed pipe diameter φd; S3. Design and manufacture a basic baffle ring assembly placed on the edge of the rotating grinding disc; S4. Design and manufacture an auxiliary baffle ring assembly positioned above the basic baffle ring assembly and fixedly connected to the inner wall of the middle shell; S5. Selectively set an adjusting baffle ring on the discharge port. This invention, through a design combining dynamic and static baffle rings, and simultaneously creating grooves on the static baffle ring, blocks unground material from being conveyed to the grinding roller for grinding, while discharging and sorting all ground material, reducing the problem of multiple grinding and over-grinding.

Description

Technical Field

[0001] This invention belongs to the field of ore crushing and grinding technology, and particularly relates to a design method for reducing the over-grinding of materials in mining roller mills. Background Technology

[0002] Ore processing requires crushing and grinding according to the requirements of mineral processing equipment. Currently, the main equipment includes crushers, ball mills, and roller mills. Among them, roller mills are widely used due to their large grinding capacity and high efficiency. Because the material bed needs a certain thickness to maintain grinding stability, there is a problem of multiple grinding processes. If grinding is repeated, the material will be over-ground, resulting in an excessively fine finished product. This increases grinding power consumption and makes it difficult to remove metallic or non-metallic minerals from the ore, reducing subsequent mineral processing efficiency. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a design method for reducing the over-grinding of materials in mining roller mills.

[0004] This invention is implemented as follows: a design method for reducing over-grinding of materials in a mining roller mill includes the following steps: S1. Based on the basic data of the mill design time and the grindability of the material, determine the grinding disc diameter Dt, the large end diameter of the grinding roller Dr1, the small end diameter of the grinding roller Dr2, and the width of the grinding roller Br according to the conventional design method for mill selection. S2. Calculate the diameter φd of the feed pipe; S3. Design and fabricate the basic retaining ring assembly: S3.1 Structural design of the basic retaining ring assembly, wherein the basic retaining ring assembly includes a basic retaining ring; an annular boss is provided on the edge of the rotating grinding disc extending upward, and a groove is provided on the upper surface of the annular boss, the groove being used to engage the basic retaining ring, and the basic retaining ring assembly rotates simultaneously with the rotating grinding disc. S3.2 Parameter design of the basic retaining ring assembly; S4. Design and manufacture auxiliary baffle ring assemblies, which are set above the basic baffle ring assembly and fixedly connected to the inner wall of the middle shell; the number of auxiliary baffle ring assemblies is the same as the number of grinding rollers, and they extend from the near end of the grinding roller to the far end of the grinding roller, forming a discharge port between each of the auxiliary baffle ring assemblies; S4.1 Design the structure of the auxiliary baffle ring assembly. The auxiliary baffle ring assembly includes a baffle plate. A fixing plate is welded to the outside of the baffle plate. The number of fixing plates is preferably set to four. The four fixing plates are radially distributed between the auxiliary baffle ring assembly and the middle shell. The auxiliary baffle ring assembly is welded into the middle shell. S4.2 Determine the design parameters of the baffle plate 14 according to the material fineness requirements; S5. Optionally, an adjustable baffle ring can be installed on the discharge port.

[0005] Furthermore, for raw materials with a particle size of less than 80 mm, good flowability, and a thin material layer after compaction, the first installation dimension is designed to be 100-150 mm, the second installation dimension is designed to be 300-500 mm, and no adjusting baffle ring is installed.

[0006] Furthermore, for raw material particles larger than 80 mm, with poor flowability and a thick material layer after compaction, the first installation dimension is designed to be 250-300 mm, the second installation dimension is designed to be 200-300 mm, and an adjustable retaining ring is installed with a height of 130-150 mm.

[0007] Furthermore, for cases where the fineness of the finished material is required to be relatively fine, i.e., the particle size radius of the ground finished product is 100 micrometers and the sieve residue is less than 15%, the first installation dimension is designed to be 250-300mm, the second installation dimension is designed to be 300-500mm, and an adjustable baffle ring is installed with a height of 20-40mm.

[0008] Furthermore, for cases where the fineness requirement of the finished material is relatively coarse, i.e. the particle size radius of the ground finished product is 100 micrometers and the sieve residue is greater than 15%, the first installation size is designed to be 100-150mm and the second installation size is designed to be 200-300mm, without installing an adjusting baffle ring.

[0009] Furthermore, the number of grinding rollers can be selectively set to two, three, or four.

[0010] The advantages and technical effects of this invention are as follows: 1. This invention combines dynamic and static design with a double-layer baffle ring. At the same time, grooves are made on the static baffle ring to block the unground material from being conveyed to the grinding roller for grinding, and all the ground material is discharged and sorted, reducing the problem of multiple grinding and over-grinding of materials.

[0011] 2. This invention controls the number of grinding cycles of materials by adjusting the position and size of the slots in the baffle ring, and ensures timely discharge; it can also meet the grinding needs of different materials and has wide adaptability.

[0012] 3. This invention is easy to operate and quick to adjust, making it suitable for widespread use. Attached Figure Description

[0013] Figure 1 This is the front view of the present invention; Figure 2This is a top view of the present invention; Figure 3 This is the invention Figure 1 Middle BB direction view; Figure 4 This is the invention Figure 1 Enlarged view of a section at point C; Figure 5 This is a partial schematic diagram of the present invention after the installation and adjustment of the baffle ring.

[0014] In the diagram: 1. Middle shell; 2. Grinding roller; 3. Rocker arm; 4. Grinding roller support; 5. Auxiliary baffle ring assembly; 6. Fixing plate; 7. Basic baffle ring assembly; 8. Rotating grinding disc; 9. Feed pipe; 10. Adjustable baffle ring; 11. Discharge port; 12. Annular boss; 13. Basic baffle ring; 14. Baffle plate; L1, First installation dimension; L2, Second installation dimension; L3, Adjustable baffle ring height. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0016] In the traditional material-blocking structure of roller mills, to ensure a stable material layer, a base retaining ring assembly 7, integrated with the grinding disc and with a height of 100-200mm, is installed on the outside of the grinding disc. The material on the rotating grinding disc 8 is blocked by the base retaining ring assembly 7. Because the upper layer of material moves faster than the lower layer, and newly fed material is generally on the upper layer, after being ground by the rollers, the material is thrown out at the top and blocked at the bottom by the base retaining ring assembly 7, then enters the next roller for further grinding, resulting in repeated grinding and over-grinding. To improve grinding efficiency, attempts are made to reduce the height of the base retaining ring assembly 7. However, after reducing the height, the material layer becomes too thin, causing excessive vibration in the mill, making it unable to operate.

[0017] To address the aforementioned problems, this invention proposes a design method for reducing the ineffective circulation volume of a mining roller mill. First, the structure employed in this method is introduced; see reference [link to relevant documentation]. Figures 1 to 5 Taking two grinding rollers as an example, since the roller mill involved is existing technology, the accompanying drawings only show the structure of the parts related to the present invention.

[0018] The mining roller mill includes a middle shell 1, which is fixed on a grinding roller support 4. The grinding roller support 4 is fixed on a ground foundation. The middle shell 1 encloses the grinding structure in the middle, serving as a seal and protection.

[0019] A rotating grinding disc 8 is installed inside the middle shell 1. The rotating grinding disc 8 is driven to rotate by a motor reducer located at its lower part. A feed pipe 9 is installed through the side wall of the middle shell 1. The outlet of the feed pipe 9 is set obliquely downward above the rotating grinding disc 8. The position of the feed pipe 9 is perpendicular to the rocker arm 3. The material falls onto the rotating grinding disc 8 through the feed pipe 9. As the rotating grinding disc 8 rotates continuously, the material is evenly dispersed and forms a dynamic material bed on the upper surface of the rotating grinding disc 8 under the action of centrifugal force. Finally, it is thrown out of the rotating grinding disc 8.

[0020] A grinding roller support 4 is symmetrically arranged on the outer side of the middle shell 1. A rocker arm 3 is hinged to the grinding roller support 4. The other end of the rocker arm 3 is located inside the middle shell 1 and is fixedly connected to the central rotating shaft of the grinding roller 2. The rocker arm 3 is inclined towards the upper surface of the rotating grinding disc 8, so that the grinding roller 2 is pressed on the rotating grinding disc 8. Driven by the rotating grinding disc 8, the grinding roller 2 rotates along its own central rotating shaft, thereby crushing the material on the rotating grinding disc 8 to form a material bed grinding.

[0021] A basic retaining ring assembly 7 is fixedly mounted on the rotating grinding disc 8. The basic retaining ring assembly 7 includes a basic retaining ring 13. An annular boss 12 extends upward from the edge of the rotating grinding disc 8, and a groove is provided on the upper surface of the annular boss 12. The groove is used to engage the basic retaining ring 13, thereby fixing the basic retaining ring 13 onto the rotating grinding disc 8. That is, the basic retaining ring assembly 7 rotates simultaneously with the rotating grinding disc 8. The annular boss 12 allows the basic retaining ring 13 to bear greater force, which is used to withstand the side pressure exerted on the basic retaining ring 13 by the grinding roller 2 during grinding. The surface of the basic retaining ring 13 is machined to ensure surface flatness, which is beneficial for the discharge of ground material. Depending on the type of ore and the particle size of the raw material, the height of the basic retaining ring 13 is designed to be 30~60mm, which is significantly reduced compared to the height of traditional retaining rings, making material discharge easier.

[0022] To ensure the stability of grinding by the grinding roller, a second layer of baffle ring, namely auxiliary baffle ring assembly 5, is designed. The auxiliary baffle ring assembly 5 is set above the basic baffle ring assembly 7. There are two auxiliary baffle ring assemblies 5, which extend from the near end of the grinding roller 2 to the far end of the grinding roller 2, that is, from the upper feed side of the grinding roller 2 along the rotation direction of the rotating grinding disc 8 to the discharge side of the grinding roller 2. Two discharge ports 11 are formed between the two auxiliary baffle ring assemblies 5, which facilitate the discharge of the ground material.

[0023] The auxiliary baffle ring assembly 5 includes a baffle plate 14, and a fixing plate 6 is welded to the outside of the baffle plate 14. The number of fixing plates 6 is preferably set to four, and the four fixing plates 6 are radially distributed between the auxiliary baffle ring assembly 5 and the middle shell 1, so that the auxiliary baffle ring assembly 5 is welded into the middle shell 1.

[0024] The inner diameter of the baffle plate 14 is larger than the inner diameter of the base baffle ring 13, and the outer diameter of the baffle plate 14 is smaller than the outer diameter of the base baffle ring 13, so as to facilitate the adjustment of the distance between the auxiliary baffle ring assembly 5 and the base baffle ring assembly 7. This arrangement ensures that the baffle plate 14 is projected inside the outer ring of the base baffle ring 13, guaranteeing that the maximum gap between them is the vertical gap. If the baffle plate 14 is projected outside the base baffle ring 13, there will be misalignment between them, and the vertical gap will not be the maximum gap; the misaligned gap will be larger than the vertical gap, resulting in excessive material being discharged from the misaligned gap. The height of the bottom surface of the auxiliary baffle ring assembly 5 from the top surface of the base baffle ring assembly 7 is set to 3~15mm; the distance should be as small as possible without causing friction. The height of the baffle plate 14 is set to 150~300mm; a higher value is chosen to avoid interference with the grinding roller 2.

[0025] This invention utilizes two auxiliary baffle ring assemblies 5. After welding the two auxiliary baffle ring assemblies 5 to the middle shell 1, a discharge port 11 is formed between them. The discharge port 11 is artificially positioned on the side where the material has been crushed by the grinding roller 2, allowing the crushed material to be discharged promptly through the discharge port 11. By adjusting the position and size of the discharge port 11, materials with different flowability and fineness requirements can be discharged. Furthermore, depending on the material grinding process, an adjustable baffle ring 10 can be installed on one of the discharge ports 11. The two ends of the adjustable baffle ring 10 are respectively bolted to the adjacent ends of the two auxiliary baffle ring assemblies 5. By replacing the adjustable baffle rings 10 with different heights, the height of the discharge port 11 can be adjusted, thereby controlling the material discharge efficiency.

[0026] Furthermore, the number of grinding rollers 2 can be selectively set to two, three, or four.

[0027] The design method for reducing ineffective circulation in mining roller mills includes the following steps: S1. Based on the basic data of the mill design time and the grindability of the material, determine the grinding disc diameter Dt, the large end diameter of the grinding roller Dr1, the small end diameter of the grinding roller Dr2, and the width of the grinding roller Br according to the conventional design method for mill selection. S2. Calculate the diameter φd of the feed pipe; S3. Design and fabricate the basic retaining ring assembly 7: S3.1 Structural design of the basic retaining ring assembly: The basic retaining ring assembly 7 includes a basic retaining ring 13; the edge of the rotating grinding disc 8 extends upward and is provided with an annular boss 12, and the upper end face of the annular boss 12 is provided with a groove for engaging the basic retaining ring 13; the basic retaining ring assembly 7 rotates simultaneously with the rotating grinding disc 8. S3.2 Parameter design of the basic retaining ring assembly; S4. Design and manufacture auxiliary baffle ring assembly 5. The auxiliary baffle ring assembly 5 is set above the basic baffle ring assembly 7 and is fixedly connected to the inner wall of the middle shell 1. The number of auxiliary baffle ring assemblies 5 is the same as the number of grinding rollers 2. They extend from the near end of the grinding roller 2 to the far end of the grinding roller 2 respectively, and a discharge port 11 is formed between each of the auxiliary baffle ring assemblies 5. S4.1 Design the structure of the auxiliary baffle ring assembly 5, the auxiliary baffle ring assembly 5 includes a baffle plate 14, the baffle plate 14 is welded to the outside of a fixing plate 6, the number of fixing plates 6 is preferably set to four, the four fixing plates 6 are radially distributed between the auxiliary baffle ring assembly 5 and the middle shell 1, and the auxiliary baffle ring assembly 5 is welded into the middle shell 1; S4.2 Determine the design parameters of the baffle plate 14 according to the fineness requirements of the finished material; S5. Optionally, an adjusting baffle ring 10 can be installed on the discharge port 10.

[0028] The design parameters of the baffle plate 14 include: the first installation dimension L1 is the distance extended from one end of the baffle plate 14 through the transverse centerline of the rotating grinding disc 8; the second installation dimension L2 is the distance extended from the other end of the baffle plate 14 through the longitudinal centerline of the rotating grinding disc 8. It should be noted that when there is a conflict between the raw material particle size parameters and the finished product particle size parameters, the design parameters of the baffle plate 14 should be selected according to the finished product particle size parameters, as detailed below: 1. For raw materials with a particle size of less than 80 mm, good flowability, and a thin material layer after compaction, the first installation dimension L1 is designed to be 100-150 mm, the second installation dimension L2 is designed to be 300-500 mm, and the adjusting baffle ring 10 is not installed.

[0029] 2. For raw materials with a particle size greater than 80 mm, poor flowability, and a thick material layer after compaction, the first installation dimension L1 is designed to be 250-300 mm, the second installation dimension L2 is designed to be 200-300 mm, the adjustable retaining ring 10 is installed, and the height of the adjustable retaining ring L3 is designed to be 130-150 mm.

[0030] 3. For cases where the fineness of the finished material is required to be fine, i.e. the particle size radius of the ground finished product is 100 micrometers and the sieve residue is less than 15%, the first installation dimension L1 is designed to be 250-300mm, the second installation dimension L2 is designed to be 300-500mm, and an adjustable baffle ring is installed. The height of the adjustable baffle ring L3 is designed to be 20-40mm.

[0031] IV. For cases where the fineness requirement of the finished material is relatively coarse, i.e. the particle size radius of the ground finished product is 100 micrometers and the sieve residue is greater than 15%, the first installation dimension L1 is designed to be 100-150mm and the second installation dimension L2 is designed to be 200-300mm, and no adjusting baffle ring is installed.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A design method for reducing over-grinding of materials in a mining roller mill, characterized in that, Includes the following steps: S1. Based on the basic data of the mill design time and the grindability of the material, determine the grinding disc diameter Dt, the large end diameter of the grinding roller Dr1, the small end diameter of the grinding roller Dr2, and the width of the grinding roller Br according to the conventional design method for mill selection. S2. Calculate the diameter φd of the feed pipe; S3. Design and fabricate the basic retaining ring assembly (7): S3.1 Structural design of the basic retaining ring assembly: The basic retaining ring assembly (7) includes a basic retaining ring (13); the edge of the rotating grinding disc (8) extends upward and is provided with an annular boss (12), and the upper end face of the annular boss (12) is provided with a slot, which is used to engage the basic retaining ring (13). The basic retaining ring assembly (7) rotates simultaneously with the rotating grinding disc (8). S3.2 Parameter design of the basic retaining ring assembly; S4. Design and manufacture auxiliary baffle ring assembly (5). The auxiliary baffle ring assembly (5) is set above the basic baffle ring assembly (7) and fixedly connected to the inner wall of the middle shell (1). The number of auxiliary baffle ring assemblies (5) is the same as the number of grinding rollers (2). They extend from the near end of the grinding roller (2) to the far end of the grinding roller (2), that is, from the upper feed side of the grinding roller along the rotation direction of the rotating grinding disc to the discharge side of the grinding roller. A discharge port (11) is formed between each of the auxiliary baffle ring assemblies (5). S4.1 Design the structure of the auxiliary baffle ring assembly. The auxiliary baffle ring assembly (5) includes a baffle plate (14). A fixing plate (6) is welded to the outside of the baffle plate (14). The number of fixing plates (6) is set to four. The four fixing plates (6) are radially distributed between the auxiliary baffle ring assembly (5) and the middle shell (1). The auxiliary baffle ring assembly (5) is welded into the middle shell (1). S4.

2. According to the fineness requirements of the finished material, determine the design parameters of the baffle (14). The design parameters of the baffle (14) include: the first installation dimension (L1) is the distance that one end of the baffle (14) extends through the transverse center line of the rotating grinding disc (8), and the second installation dimension (L2) is the distance that the other end of the baffle (14) extends through the longitudinal center line of the rotating grinding disc (8). S5. Selectively, an adjusting baffle ring (10) is set on the discharge port (11).

2. The design method for reducing over-grinding of materials in a mining roller mill according to claim 1, characterized in that: In step S4.2, for raw material particles smaller than 80 mm, with good flowability and thin material layer after compaction, the first installation dimension (L1) is designed to be 100-150 mm and the second installation dimension (L2) is designed to be 300-500 mm, and no adjusting baffle ring (10) is installed.

3. The design method for reducing over-grinding of materials in a mining roller mill according to claim 1, characterized in that: In step S4.2, for raw material particles larger than 80 mm, with poor flowability and thick material layer after compaction, the first installation dimension (L1) is designed to be 250-300 mm, the second installation dimension (L2) is designed to be 200-300 mm, and the adjusting baffle ring (10) is installed. The height of the adjusting baffle ring (L3) is designed to be 130-150 mm.

4. The design method for reducing over-grinding of materials in a mining roller mill according to claim 1, characterized in that: In step S4.2, for cases where the fineness of the finished product is required to be fine, i.e. the particle size radius of the ground finished product is 100 micrometers and the sieve residue is less than 15%, the first installation dimension (L1) is designed to be 250-300mm, the second installation dimension (L2) is designed to be 300-500mm, and the adjusting baffle ring (10) is installed. The height of the adjusting baffle ring (L3) is designed to be 20-40mm.

5. The design method for reducing over-grinding of materials in a mining roller mill according to claim 1, characterized in that: In step S4.2, for cases where the fineness requirement of the finished product is relatively coarse, that is, the particle size radius of the ground finished product is 100 micrometers and the sieve residue is greater than 15%, the first installation dimension (L1) is designed to be 100-150mm and the second installation dimension (L2) is designed to be 200-300mm, and no adjusting baffle ring is installed.

6. The design method for reducing over-grinding of materials in a mining roller mill according to claim 1, characterized in that: In step S1, the number of grinding rollers (2) can be selectively set to two, three or four.

7. The design method for reducing over-grinding of materials in a mining roller mill according to claim 1, characterized in that: The height of the bottom surface of the auxiliary retaining ring assembly (5) from the top surface of the basic retaining ring assembly (7) in step S4 is 3~15mm.

8. The design method for reducing over-grinding of materials in a mining roller mill according to claim 1, characterized in that: In step S3.1, the height of the basic retaining ring (13) is designed to be 30~60mm.

9. The design method for reducing over-grinding of materials in a mining roller mill according to claim 1, characterized in that: In step S4.1, the height of the baffle plate (14) is designed to be 150~300mm.

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