Energy-saving variable-speed ball mill for realizing narrow-fraction ore grinding and method thereof

Abstract

The invention discloses an energy-saving variable-speed ball mill for realizing narrow-fraction ore grinding and a method of the energy-saving variable-speed ball mill, and belongs to the technical field of ball mills. The output end of the cylinder body is provided with an ore discharge chute, the surface of the ore discharge chute is provided with a grading chute, the bottom of the grading chute is provided with a demagnetizing elbow, the output end of the demagnetizing elbow is provided with a fine-fraction electronic scale, and one side of the fine-fraction electronic scale is provided with a coarse-fraction electronic scale; and recovery chutes are arranged at the output ends of the coarse-fraction electronic scale and the fine-fraction electronic scale. Timing sampling is performed through the ore discharge chute and the grading chute, after residual magnetism of ore discharge products is eliminated through the demagnetizing elbow, coarse and fine fuzzy grading is completed on the electronic scale by means of the high flow speed of ore pulp and the inertia and sedimentation characteristics of minerals of different size fractions, and large-cardinal-number analysis of multiple sampling is adopted; and only the proportions of the coarse and fine fractions of the ore grinding products in different time periods are compared, so that the ore grinding effects in different time periods are judged, and other parameters are adjusted to stabilize production.

Description

Technical Field

[0001] The present invention relates to the technical field of ball mills, and more particularly to an energy-saving variable-speed ball mill for achieving narrow-size particle grinding and a method thereof. Background Art

[0002] Ball mill is a widely used dissociation equipment after mineral crushing. It drives the lifting and falling of grinding media and minerals through the centrifugal force of rotation, realizing the impact, collision and grinding between grinding media and minerals. When the mill speed is too low, the impact force of grinding media and materials is insufficient, and the fine grinding effect is poor; when the mill speed is too high, the lifting height is too high and the impact force is too large, resulting in over-grinding or part of the grinding media and minerals move in a circle with the mill without grinding. In addition, during the mining and selection process, the properties of the raw ore fluctuate frequently. At a fixed speed, over-grinding and difficult grinding usually occur, resulting in the loss of concentrate and reduced processing capacity of the selection system; in addition, with the cost reduction of industrial upgrading and the promotion of smart grinding, the requirements for grinding energy consumption indicators are getting higher and higher, and the tracking and judgment of the grinding effect also need to be accurate and timely.

[0003] At present, the feedback effect of the particle size detection instruments for grinding products on the market is not outstanding. How to use a simpler method to accurately track the grinding effect, achieve narrow particle size grinding with lower energy consumption to reduce over-grinding and maintain a higher processing capacity is a difficult problem currently faced by the concentrator. Summary of the invention

[0004] 1. Technical problem to be solved by the invention

[0005] In view of the defects and shortcomings of the prior art, the present invention provides an energy-saving variable-speed ball mill and method for achieving narrow particle size grinding. The present invention takes samples at regular intervals on the discharge chute and the grading chute. After the demagnetization elbow eliminates the residual magnetism of the discharge product, the high flow rate of the slurry itself and the inertia and sedimentation characteristics of minerals of different particle sizes are utilized to complete coarse and fine fuzzy classification on an electronic scale. A large cardinality analysis of multiple samplings is adopted to compare only the coarse and fine particle size proportions of the grinding products in different time periods, thereby obtaining a judgment on the quality of the grinding effect in different time periods, and then adjusting other parameters to stabilize production.

[0006] 2. Technical solution

[0007] In order to achieve the above object, the technical solution provided by the present invention is:

[0008] The energy-saving variable-speed ball mill for achieving narrow-size grinding of ore of the present invention comprises a cylinder, wherein the outer ring of the cylinder is provided with a fixed gear, and the fixed gear is meshed with a driving gear; the inner ring of the driving gear is provided with a transmission shaft, and one end of the transmission shaft penetrates the driving gear and is connected with a permanent magnet motor;

[0009] The inner wall of the cylinder is attached with a magnetic lining plate, and the inner cavity of the cylinder is filled with grinding media; the input end of the cylinder is connected to the ore feeder, the output end of the cylinder is connected to the ore discharger, the output end of the ore discharger is provided with an ore discharge box, and the bottom of the ore discharger is provided with an ore discharge device;

[0010] The ore discharging device comprises an ore discharging chute and a grading chute; a grading chute is arranged on the surface of the ore discharging chute, a flap valve is arranged at the connection between the ore discharging chute and the grading chute, a demagnetization elbow is arranged at the bottom of the grading chute, a fine-grained electronic scale is arranged at the output end of the demagnetization elbow, a coarse-grained electronic scale is arranged on one side of the fine-grained electronic scale, a recovery chute is arranged at the output ends of the coarse-grained electronic scale and the fine-grained electronic scale, and the output end of the recovery chute is connected to the ore discharging chute.

[0011] Furthermore, a sealing device is provided at the connection between the feeder and the cylinder.

[0012] Furthermore, a hydraulic push rod is provided at one end of the flap valve, and a hydraulic motor is provided at the input end of the hydraulic push rod.

[0013] Furthermore, the grinding media are ceramic balls with a ball diameter of 20mm to 30mm and steel balls with a ball diameter of 30mm, the grinding medium filling rate is 40% to 42%, and the ball mill grinds at a grinding concentration of 65% to 68%.

[0014] Furthermore, the slope of the grading chute is not less than 15°, and a water supply pipe is connected to the grading chute. An electric valve is provided on the water supply pipe. The water supply pipe regularly supplies water to reduce the discharge concentration and increase the discharge slurry flow rate.

[0015] Furthermore, the coarse particle electronic scale and the fine particle electronic scale are both installed with a slope of 3°, and a flushing water pipe is provided at the upper end of the coarse particle electronic scale and the fine particle electronic scale, and an electric valve is provided on the surface of the flushing water pipe.

[0016] Furthermore, a grinding machine base is arranged on the side of the cylinder.

[0017] Furthermore, a slow-drive motor is provided on one side of the driving gear, a slow-drive shaft is provided on the output end of the slow-drive motor, and a nesting device is provided on the shaft body of the slow-drive shaft. During the daily maintenance process of the ball mill, the permanent magnet motor stops driving, and the slow-drive motor drives the driving gear to rotate at a low speed through the slow-drive shaft and the nesting device.

[0018] A method for realizing energy-saving variable-speed ball mill for narrow particle size grinding: sampling is performed regularly through a discharge chute and a grading chute, and after a demagnetization elbow eliminates the residual magnetism of the discharge product, the high flow rate of the slurry itself and the inertia and sedimentation characteristics of minerals of different particle sizes are utilized. The minerals have an initial velocity after flowing out through the demagnetization elbow. At this initial velocity, the movement trajectories of granular minerals of different finenesses have different arcs. Therefore, coarse and fine fuzzy classification can be completed on a coarse particle size electronic scale and a fine particle size electronic scale. A large cardinality analysis of multiple samplings is used to compare the coarse and fine particle size proportions of the grinding products in different time periods, thereby obtaining a judgment on the quality of the grinding effects in different time periods.

[0019] 3. Beneficial effects

[0020] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0021] The present invention takes samples at regular intervals on the discharge chute and the grading chute, and after the demagnetization elbow eliminates the residual magnetism of the discharge product, it uses the high flow rate of the slurry itself and the inertia and sedimentation characteristics of minerals of different particle sizes to complete coarse and fine fuzzy classification on an electronic scale, abandons the concept of pursuing precise particle size distribution, and directly abandons the problems of difficult sampling, high price, high failure rate and difficult maintenance of precision instruments for detecting particle size. It adopts large cardinality analysis of multiple samplings and only compares the coarse and fine particle size proportions of the grinding products in different time periods, so as to obtain the judgment of the quality of the grinding effect in different time periods, and then adjust other parameters to stabilize production.

[0022] The present invention reduces the average density and ball diameter of the grinding medium, reduces the grinding power consumption and ball consumption of the ball mill, improves the filling rate and strengthens the grinding effect by mixing ceramic balls and steel balls; combines a variable frequency permanent magnet motor with a simpler structure and higher driving efficiency to achieve mill speed change, appropriately adjusts the mill speed according to the discharge particle size analysis, timely adjusts other parameters, improves the over-grinding phenomenon, achieves narrow particle size grinding, and significantly reduces grinding energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a front view of the present invention;

[0024] Figure 2 It is a partial top view of the present invention.

[0025] In the figure: 1. permanent magnet motor; 2. mill body; 3. transmission shaft; 4. driving gear; 5. nesting device; 6. slow drive motor; 7. cylinder; 8. feeder; 9. sealing device; 10. grinding medium; 11. magnetic lining; 12. fixed gear; 13. discharger; 14. discharge box; 15. discharge chute; 16. hydraulic motor; 17. hydraulic push rod; 18. flap valve; 19. grading chute; 20. electric valve; 21. water supply pipe; 22. demagnetization elbow; 23. coarse particle electronic scale; 24. fine particle electronic scale; 25. recovery chute; 26. flushing water pipe; 27. slow drive shaft. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0027] Example 1

[0028] from Figure 1-2 It can be seen that the energy-saving variable-speed ball mill for achieving narrow particle size grinding in this embodiment includes a cylinder 7, a fixed gear 12 is installed on the outer ring of the cylinder 7, and the fixed gear 12 is meshed with the driving gear 4; the inner ring of the driving gear 4 is provided with a transmission shaft 3, one end of the transmission shaft 3 passes through the driving gear 4 and is connected to a permanent magnet motor 1; the permanent magnet motor 1 drives the driving gear 4 and the fixed gear 12 to drive the cylinder 7 to rotate through the transmission shaft 3;

[0029] A magnetic lining plate 11 is attached to the inner wall of the cylinder 7, and the inner cavity of the cylinder 7 is filled with a grinding medium 10; the grinding medium 10 uses ceramic balls with a ball diameter of 20 mm to 30 mm and steel balls with a ball diameter of 30 mm, and the filling rate of the grinding medium 10 is 40% to 42%. The ball mill grinds the ore under the condition of a grinding concentration of 65% to 68%;

[0030] During grinding, a layer of steel balls and mineral powder is adsorbed on the inner surface of the cylinder 7 to reduce the impact between the grinding medium 10 and the magnetic liner 11, protect the magnetic liner 11 and reduce noise;

[0031] The input end of the cylinder 7 is connected to a feeder 8, and a sealing device 9 is provided at the connection between the feeder 8 and the cylinder 7 to prevent the grinding medium 10 from backflowing due to the high liquid level inside the cylinder 7 under a high filling rate. The output end of the cylinder 7 is connected to a discharger 13, and a discharge box 14 is provided at the output end of the discharger 13. The discharge box 14 is used to collect large particles of stubborn stones and abnormally discharged grinding media 10, which is convenient for safe cleaning during mill production; a discharge device is provided at the bottom of the discharger 13; the underscreen product of the discharger 13 enters a discharge chute 15;

[0032] The ore discharging device includes an ore discharging chute 15 and a grading chute 19; the grading chute 19 is arranged on the surface of the ore discharging chute 15, and a flap valve 18 is arranged at the connection between the ore discharging chute 15 and the grading chute 19; a hydraulic push rod 17 is arranged at one end of the flap valve 18, and a hydraulic motor 16 is arranged at the input end of the hydraulic push rod 17;

[0033] A demagnetization elbow 22 is provided at the bottom of the grading chute 19, and a fine-grained electronic scale 24 is provided at the output end of the demagnetization elbow 22. A coarse-grained electronic scale 23 is provided on one side of the fine-grained electronic scale 24. A recovery chute 25 is provided at the output ends of the coarse-grained electronic scale 23 and the fine-grained electronic scale 24. The output end of the recovery chute 25 is connected to the discharge chute 15, and all the slurries are finally collected in the discharge chute 15.

[0034] The slope of the grading chute 19 is not less than 15°. The grading chute 19 is connected with a water supply pipe 21, on which an electric valve 20 is arranged. The water supply pipe 21 replenishes water regularly to reduce the discharge concentration and increase the discharge slurry flow rate.

[0035] Before the discharged ore products enter the classification chute 19, the electric valve 20 of the water supply pipe 21 is opened to reduce the concentration of the discharged ore products and increase the slurry flow rate, so that the slurry is in a turbulent state;

[0036] The coarse-grained electronic scale 23 and the fine-grained electronic scale 24 are both installed with a 3° slope to allow the minerals on the surface of the electronic scales to drain naturally. A flushing water pipe 26 is provided at the upper end of the coarse-grained electronic scale 23 and the fine-grained electronic scale 24, and an electric valve 20 is provided on the surface of the flushing water pipe 26 for flushing the minerals on the surface of the electronic scales.

[0037] The coarse-grained electronic scale 23 and the fine-grained electronic scale 24 are combined with the flap valve 18 to collect the discharged ore products for classification and weighing, and analyze the grinding effect;

[0038] The ball mill can also be equipped with an automatic valve switch system, an electronic scale signal collection and analysis system and a power current monitoring system. According to the comparative analysis of the coarse and fine particle size measurements at regular intervals, the permanent magnet motor frequency can be adjusted to change the mill speed.

[0039] The present invention aims to solve the problems of over-grinding, high grinding energy consumption, insufficient detection accuracy and difficult maintenance of detection instruments, and to provide a grinding machine that can track the grinding effect through simple equipment, combine lighter grinding media and adjustable speed, and realize energy-saving grinding of narrow particle size.

[0040] The present invention takes samples at regular intervals on the discharge chute and the grading chute, and after the demagnetization elbow eliminates the residual magnetism of the discharge product, it uses the high flow rate of the slurry itself and the inertia and sedimentation characteristics of minerals of different particle sizes to complete coarse and fine fuzzy classification on an electronic scale, abandons the concept of pursuing precise particle size distribution, and directly abandons the problems of difficult sampling, high price, high failure rate and difficult maintenance of precision instruments for detecting particle size. It adopts large cardinality analysis of multiple samplings and only compares the coarse and fine particle size proportions of the grinding products in different time periods, so as to obtain the judgment of the quality of the grinding effect in different time periods, and then adjust other parameters to stabilize production.

[0041] The present invention reduces the average density and ball diameter of the grinding medium, reduces the grinding power consumption and ball consumption of the ball mill, improves the filling rate and strengthens the grinding effect by mixing ceramic balls and steel balls; combines a variable frequency permanent magnet motor with a simpler structure and higher driving efficiency to achieve mill speed change, appropriately adjusts the mill speed according to the discharge particle size analysis, timely adjusts other parameters, improves the over-grinding phenomenon, realizes narrow particle size grinding, and reduces the grinding energy consumption by up to 10%.

[0042] Example 2

[0043] from Figure 1 It can be seen that in this embodiment, an energy-saving variable-speed ball mill for achieving narrow particle size grinding is provided with a mill base 2 on the side of the cylinder 7;

[0044] A slow-drive motor 6 is provided on one side of the driving gear 4, a slow-drive shaft 27 is provided on the output end of the slow-drive motor 6, and a nesting device 5 is provided on the shaft body of the slow-drive shaft 27. During the daily maintenance process of the ball mill, the permanent magnet motor 1 stops driving, and the slow-drive motor 6 drives the driving gear 4 to rotate at a low speed through the slow-drive shaft 27 and the nesting device 5.

[0045] Example 3

[0046] from Figure 2 It can be seen that the energy-saving variable-speed ball mill for achieving narrow particle size grinding in the present embodiment takes samples at regular intervals through the discharge chute 15 and the grading chute 19. After the demagnetization elbow 22 eliminates the residual magnetism of the discharge product, the high flow rate of the slurry itself and the inertia and sedimentation characteristics of minerals of different particle sizes are utilized. The minerals have an initial velocity after flowing out through the demagnetization elbow 22. At this initial velocity, the movement trajectories of granular minerals of different finenesses will have different curvatures. Therefore, coarse and fine fuzzy classification can be completed on the coarse particle size electronic scale 23 and the fine particle size electronic scale 24. The large cardinality analysis of multiple samplings is used to compare the coarse and fine particle size proportions of the grinding products in different time periods, thereby obtaining a judgment on the quality of the grinding effects in different time periods.

[0047] Example 4

[0048] from Figure 1-2It can be seen that the energy-saving variable-speed ball mill for narrow-size grinding in this embodiment, in an industrial test at a certain iron-selection plant, has two series under the same production conditions, for a two-stage grinding and classification system with closed-circuit grinding and classification, series 1 uses a Φ3660 mill with a manganese steel liner, and series 2 uses a Φ4060 mill with a magnetic liner; the effective volume of the two mills is 55m 3 ; The nano ceramic ball diameter is Φ30mm:Φ25mm:Φ20mm=20%:60%:20%, the filling rate is 35%, the steel ball diameter is Φ30mm, the filling rate is 6%, the grinding concentration is 65% to 68%, and the grinding is carried out by the mill; Both series are driven by the same power variable frequency permanent magnet motor, the same ore source, the same processing capacity and the same classification system. The flap valve and the water supply electric valve of the classification chute are opened and closed every 15 minutes, and the electronic scale collects data every 30 seconds and records the proportion of coarse and fine particles.

[0049] For the softer magnetite ore, the speed of the 1st and 2nd series mills is controlled to 19 / min and 18r / min respectively.

[0050] The particle size distribution of the products of the 1 series grinding and classification system is shown in Table 1, and the particle size distribution of the products of the 2 series grinding and classification system is shown in Table 2. The return sand ratio, new ball mill production rate, over-grinding particle grade production rate and mill current of the 1 series and 2 series are shown in Table 3.

[0051] Table 1 Series of grinding product particle size distribution (yield / %)

[0052] Particle size / mm 1# Ore discharge Feeding (sand settling) overflow +0.3 3.58 7.18 0 -0.3～+0.15 14.02 18.89 1.57 -0.15～+0.1 20.09 21.27 7.22 -0.1～+0.076 17.52 17.83 5.75 -0.076～+0.045 24.28 24.77 18.20 -0.045～+0.03 6.77 4.44 13.39 -0.030 13.74 5.62 53.87 total 100.00 100.00 100.00 -0.076 44.79 34.83 85.46

[0053] Table 2 Series of grinding product particle size distribution (yield / %)

[0054] Particle size / mm Ore discharge Feeding (sand settling) overflow +0.3 4.85 20.33 0.00 -0.3～+0.15 19.71 21.20 2.73 -0.15～+0.1 24.97 24.02 6.76 -0.1～+0.076 14.96 11.11 5.86 -0.076～+0.045 21.98 9.70 15.88 -0.045～+0.03 5.47 6.33 13.54 -0.030 8.06 7.31 55.23 total 100.00 100.00 100.00 -0.076 35.51 23.34 84.65

[0055] Table 3 - Return sand ratio, ball mill regeneration and mill current

[0056]

[0057] The above data show that, compared with the traditional grinding mill, the grinding products of the present invention as a whole have a relatively higher new production rate of -0.076mm particle size in the discharge ore, the +0.15mm particle size of the 2 series in the discharge ore products is relatively 6.96% higher, the -0.045mm particle size yield is relatively lower, especially the -0.03mm particle size yield is lower, which indicates that the over-grinding phenomenon is improved; the return sand ratio of the grinding and grading system is similar, the mill current is lower, and the grinding power consumption is reduced by 11.59%.

[0058] The present invention and its embodiments are described schematically above, and the description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and designs a structural method and an embodiment similar to the technical solution without creativity without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. An energy-saving variable-speed ball mill for achieving narrow-size grinding, comprising a cylinder (7), characterized in that: The outer ring of the cylinder (7) is provided with a fixed gear (12), which meshes with the driving gear (4); the inner ring of the driving gear (4) is provided with a transmission shaft (3), one end of the transmission shaft (3) passes through the driving gear (4) and is connected to a permanent magnet motor (1); The inner wall of the cylinder (7) is attached with a magnetic lining plate (11), and the inner cavity of the cylinder (7) is filled with a grinding medium (10); the input end of the cylinder (7) is connected with an ore feeder (8), the output end of the cylinder (7) is connected with an ore discharger (13), the output end of the ore discharger (13) is provided with an ore discharge box (14), and the bottom of the ore discharger (13) is provided with an ore discharge device; The ore discharging device comprises an ore discharging chute (15) and a grading chute (19); the grading chute (19) is arranged on the surface of the ore discharging chute (15); a flap valve (18) is arranged at the connection between the ore discharging chute (15) and the grading chute (19); a demagnetization elbow (22) is arranged at the bottom of the grading chute (19); a fine-grained electronic scale (24) is arranged at the output end of the demagnetization elbow (22); a coarse-grained electronic scale (23) is arranged on one side of the fine-grained electronic scale (24); a recovery chute (25) is arranged at the output ends of the coarse-grained electronic scale (23) and the fine-grained electronic scale (24); and the output end of the recovery chute (25) is connected to the ore discharging chute (15).

2. The energy-saving variable-speed ball mill for achieving narrow-size grinding according to claim 1, characterized in that: A sealing device (9) is provided at the connection between the feeder (8) and the cylinder (7).

3. The energy-saving variable-speed ball mill for achieving narrow-size grinding according to claim 2, characterized in that: A hydraulic push rod (17) is arranged at one end of the flap valve (18), and a hydraulic motor (16) is arranged at the input end of the hydraulic push rod (17).

4. The energy-saving variable-speed ball mill for achieving narrow-size grinding according to claim 3, characterized in that: The grinding medium (10) is selected from ceramic balls with a ball diameter of 20mm to 30mm and steel balls with a ball diameter of 30mm. The filling rate of the grinding medium (10) is 40% to 42%. The ball mill grinds the ore at a grinding concentration of 65% to 68%.

5. The energy-saving variable-speed ball mill for narrow-size grinding according to claim 4, characterized in that: The slope of the grading chute (19) is not less than 15°. The grading chute (19) is connected to a water supply pipe (21), on which an electric valve (20) is arranged. The water supply pipe (21) regularly supplies water to reduce the discharge concentration and increase the discharge slurry flow rate.

6. The energy-saving variable-speed ball mill for achieving narrow-size grinding according to claim 5, characterized in that: The coarse particle electronic scale (23) and the fine particle electronic scale (24) are both installed with a slope of 3°. A flushing water pipe (26) is arranged at the upper end of the coarse particle electronic scale (23) and the fine particle electronic scale (24), and an electric valve (20) is arranged on the surface of the flushing water pipe (26).

7. The energy-saving variable-speed ball mill for narrow-size grinding according to claim 1, characterized in that: A grinding machine base (2) is arranged on the side of the cylinder (7).

8. The energy-saving variable-speed ball mill for narrow-size grinding according to claim 7, characterized in that: A slow drive motor (6) is arranged on one side of the driving gear (4), a slow drive shaft (27) is arranged on the output end of the slow drive motor (6), and a nesting device (5) is arranged on the shaft body of the slow drive shaft (27). During the routine maintenance process of the ball mill, the permanent magnet motor (1) stops driving, and the slow drive motor (6) drives the driving gear (4) to rotate at a low speed through the slow drive shaft (27) and the nesting device (5).

9. The method for realizing energy-saving variable-speed ball mill for narrow-size grinding according to claim 6, characterized in that: By taking samples at regular intervals through the discharge chute (15) and the grading chute (19), after the demagnetization elbow (22) eliminates the residual magnetism of the discharged ore products, the high flow rate of the slurry itself and the inertia and sedimentation characteristics of minerals of different particle sizes are utilized. The minerals have an initial velocity after flowing out through the demagnetization elbow (22). At this initial velocity, the movement trajectories of the granular minerals of different finenesses have different arcs. Therefore, the coarse-fine fuzzy grading can be completed on the coarse-grained electronic scale (23) and the fine-grained electronic scale (24). The large cardinality analysis of multiple samplings is used to compare the coarse-fine particle size ratios of the grinding products in different time periods, thereby obtaining a judgment on the quality of the grinding effects in different time periods.

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