Method for calibrating filling rate of ball mill based on DEM

Abstract

This invention discloses a ball mill filling rate calibration method based on EDEM (Digital Emission Modeling). The method includes the following steps: S1: Determine simulation parameters based on actual operating conditions and construct a simulation environment in EDEM software; S2: Adjust the grinding conditions of the ball mill and conduct simulation experiments under different grinding conditions; statistically analyze the changes in the grinding media trajectory at the overflow weir baffle at the ball mill discharge port under different grinding conditions, and construct a grinding media trajectory database; S3: Based on real-time images of the grinding media trajectory at the overflow weir baffle at the ball mill discharge port collected on-site, and combined with the current operating conditions, compare the grinding media trajectory images under different operating conditions in the grinding media trajectory database, and calibrate to obtain the current internal filling rate of the ball mill. This invention enables high-precision, real-time monitoring of the internal filling rate of a ball mill operating with mixed grinding media, which is beneficial for maintaining the continuous stability of the production process, thereby promoting the improvement of overall efficiency and product quality.

Description

Technical Field

[0001] This invention relates to the technical field of grinding, and specifically to a method for calibrating the filling rate of a ball mill based on DEM. Background Technology

[0002] Ball mills play a crucial role in mineral processing, serving as an indispensable core piece of equipment in the mineral processing flow. They utilize grinding media to grind ore, achieving thorough separation of the effective components from gangue. This process not only improves the liberation of minerals but also enhances the efficiency of subsequent beneficiation operations, such as flotation, magnetic separation, or gravity separation, thereby increasing the overall recovery rate and economic benefits of the mineral processing process.

[0003] Although modern ball mills are equipped with advanced automated control systems and are gradually entering a new era of intelligent control, enabling them to monitor and adjust operating parameters in real time to optimize production efficiency, experience still plays an important role in setting specific operating parameters. This is mainly because the ball milling process is complex and involves the interaction of various factors such as material properties, mill structure, type of grinding media, ball mill filling rate, rotational speed, and power consumption.

[0004] Against the backdrop of reducing grinding energy consumption in mineral processing plants, achieving cost reduction and efficiency improvement, energy saving and consumption reduction, and reaching the goals of carbon peaking and carbon neutrality, the use of ceramic balls to partially replace steel balls as grinding media in ball mills during the fine grinding stage has begun to be widely applied in mineral processing plants. Compared with using a single ball milling media, grinding with a mixture of ceramic balls and steel balls presents a stronger demand in terms of stabilizing the ball mill media filling rate and the mass ratio of different grinding media inside the mill, which cannot be met by the current experience-based ball addition mode. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the above-mentioned background technology and provide a ball mill filling rate calibration method based on DEM. This method can combine DEM simulation results with actual on-site working conditions to determine the current filling rate and mass ratio of the mixed grinding media inside the ball mill. This provides guidance for the single ball addition amount in production operations, so that the filling rate inside the ball mill is stabilized at a certain optimal value, thereby improving work efficiency and further increasing economic benefits.

[0006] To achieve the above objectives, the present invention provides a DEM-based method for calibrating the filling rate of a ball mill, comprising the following steps:

[0007] S1: Determine simulation parameters based on actual working conditions and build a simulation environment in EDEM software;

[0008] S2: Adjust the grinding conditions of the ball mill and conduct simulation tests under different grinding conditions; statistically analyze the changes in the grinding media trajectory at the overflow weir baffle of the ball mill discharge port under different grinding conditions, draw images of the grinding media trajectory under different grinding conditions, and construct a grinding media trajectory database by combining the images of the grinding media trajectory measured under different working conditions in actual production.

[0009] S3: Based on the real-time images of the grinding media movement trajectory at the overflow weir baffle of the ball mill discharge port, combined with the current working conditions, and compared with the grinding media movement trajectory images under different working conditions in the grinding media movement trajectory database, the current internal filling rate of the ball mill is obtained through calibration.

[0010] Furthermore, step S1 specifically includes the following methods:

[0011] S11: Obtain ball mill parameters, including: ball mill model and speed, type and proportion of grinding media used, type of liner used and its appearance after installation;

[0012] S12: In 3D modeling software, construct a 3D model based on the ball mill model and the shape of the liner after installation;

[0013] S13: In the EDEM software, set the particle parameters based on the material properties of the grinding media and ore used in the ball mill, and set the equipment material parameters and operating mode based on the material properties of the liner and the ball mill speed.

[0014] S14: Conduct calibration tests based on the on-site production environment, and conduct subsequent simulation tests based on the parameters calibrated by the calibration tests.

[0015] Furthermore, step S14 specifically includes the following methods:

[0016] S141: Empty the inside of the ball mill, load it with grinding media of known filling ratio, and conduct trial operation; when it is stable, collect images of the movement trajectory of the grinding media at the ball mill discharge port and record the corresponding operating information.

[0017] S142: Then, two consecutive ball replenishment tests were conducted. After each test, images of the grinding media movement trajectory at the ball mill discharge port were collected after the operation stabilized, and the operating condition information was recorded.

[0018] S143: Using the ball mill discharge port grinding media motion trajectory image determined by three known filling rates as a benchmark, the particle parameters and equipment material parameters in step S13 are calibrated by conducting simulation tests, and subsequent simulation tests are conducted based on the calibrated parameters.

[0019] Furthermore, in step S2, adjusting the grinding conditions of the ball mill includes adjusting the mass ratio of grinding media, ball loading regime, filling rate, ore quantity, or grinding concentration within the ball mill.

[0020] Furthermore, the ball mill is a horizontal overflow ball mill.

[0021] Furthermore, the grinding media includes steel balls and ceramic balls.

[0022] Furthermore, the ball loading regime of the grinding media is Φ30mm:Φ25mm:Φ20mm = 20%~50%: 20%~30%: 20%~50%.

[0023] Furthermore, the filling rate of the grinding media is 32% to 45%.

[0024] Furthermore, the amount of ore in the grinding media is 260t / h to 400t / h.

[0025] Furthermore, the grinding concentration of the grinding media is 65% to 70%.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] Firstly, compared to the existing technology that relies solely on grinding effect and experience to determine the amount of balls added, the ball mill filling rate calibration method based on DEM of this invention is based on the necessary modification to the ball mill discharge port when using ceramic balls, namely the overflow weir baffle structure of the ball mill discharge port. It proposes a method to calibrate the current filling rate inside the ball mill by observing the movement trajectory of the grinding media at the ball mill discharge port. This provides guidance for determining the detailed amount of balls added under different working conditions during on-site production, enabling the ball mill production to stabilize at a specific optimal value, improving work efficiency, and further increasing economic benefits.

[0028] Secondly, the DEM-based ball mill filling rate calibration method of this invention innovatively introduces a new filling rate calibration strategy, which analyzes the movement path of the grinding media on the tail baffle surface of the ball mill, thereby achieving high-precision, real-time monitoring of the internal filling rate of the ball mill using ceramic balls and steel balls as mixed grinding media during operation. This is beneficial to maintaining the ability of the production process to remain stable, thereby promoting the improvement of overall efficiency and product quality. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a DEM-based ball mill filling rate calibration method;

[0030] Figure 2 This is a schematic diagram of the grinding media movement trajectory window observed during the simulation process of Embodiment 1 of the present invention at different filling ratios;

[0031] Figure 3 This is a distribution diagram of the grinding media movement trajectory corresponding to different filling ratios in Embodiment 1 of the present invention;

[0032] Figure 4 This is a schematic diagram of the grinding media movement trajectory window observed during the simulation process of Embodiment 2 of the present invention at different filling rates;

[0033] Figure 5 This is a distribution diagram of the grinding media movement trajectory corresponding to different filling ratios in Embodiment 2 of the present invention;

[0034] Figure 6 This is a schematic diagram of the grinding media movement trajectory window observed during the simulation process of Embodiment 3 of the present invention at different filling rates;

[0035] Figure 7 This is a distribution diagram of the grinding media movement trajectory corresponding to different filling ratios in Embodiment 3 of the present invention. Detailed Implementation

[0036] The following examples illustrate the implementation of the present invention in detail, but they do not constitute a limitation on the invention and are merely illustrative. Furthermore, explaining the advantages of the present invention will make it clearer and easier to understand.

[0037] like Figure 1 The ball mill filling rate calibration method based on DEM (Discrete Element Method) shown includes the following steps:

[0038] Step S1: Determine simulation parameters based on actual working conditions and construct the simulation environment in EDEM software; specifically, this includes the following steps:

[0039] S11: Obtain ball mill parameters, including: ball mill model and speed, type and proportion of grinding media used, type of liner used and its post-installation form.

[0040] S12: In 3D modeling software (SolidWorks or 3ds Max), construct a 3D model based on the ball mill model and the shape of the liner after installation.

[0041] S13: In EDEM software (a simulation software based on the discrete element method, developed by Altair), the particle parameters are set based on the material properties of the grinding media and ore used in the ball mill, and the equipment material parameters and operating mode are set based on the material properties of the liner and the ball mill speed.

[0042] S14: Conduct calibration tests based on the on-site production environment. Specific steps include:

[0043] S141: Empty the inside of the ball mill, load it with grinding media of known filling ratio, and conduct trial operation; when it is stable, collect images of the movement trajectory of the grinding media at the ball mill discharge port and record the corresponding operating information.

[0044] S142: Then, two consecutive ball replenishment tests are conducted. After each test, images of the medium's motion trajectory are collected and the operating conditions are recorded once the operation is stable.

[0045] S143: Using the ball mill discharge port grinding media motion trajectory image determined by three known filling rates as a benchmark, the particle parameters and equipment material parameters in step S13 are calibrated by conducting simulation tests, and subsequent simulation tests are conducted based on the calibrated parameters.

[0046] Step S2: Referring to the preliminary laboratory test results and on-site working conditions, modify the grinding conditions of the ball mill, such as the mass ratio of grinding media, ball loading regime, filling rate, ore quantity, or grinding concentration, and conduct simulation tests. The grinding media in the ball mill mainly include steel balls and ceramic balls, with a grinding media mass ratio of steel balls:ceramic balls = 1:9 to 7:3. The single grinding media ball loading regime is Φ30mm:Φ25mm:Φ20mm = 20% to 50%: 20% to 30%: 20% to 50%. The filling rate is 32% to 45%, the ore quantity is 260t / h to 400t / h, and the grinding concentration is 65% to 75%. Observe and statistically analyze the changes in the media movement trajectory at the overflow weir baffle at the discharge port under different parameters, draw media movement trajectory images under different conditions, and construct a media movement trajectory database by combining the media movement trajectory images measured under different working conditions in actual production.

[0047] Step S3: Based on the real-time images of the grinding media movement trajectory at the ball mill discharge port collected on-site, and combined with the current working conditions, compare the grinding media movement trajectory images under different working conditions in the existing database to determine the current filling rate in the ball mill.

[0048] Example 1:

[0049] Step S1: A modification test was conducted on a 4270×7300 overflow ball mill (two-stage) at a certain factory. Preliminary preparations included determining the shape and distribution of the liner based on actual operating conditions, further establishing a model based on the internal shape of the ball mill (mill speed 15.7 r / min), and setting simulation parameters based on the material properties of the steel balls, ceramic balls, ore, and liner. The liner used was manganese steel. Particle parameters were set based on the material properties of the grinding media and ore used in the ball mill. Equipment material parameters and operating modes were set based on the material properties of the liner and the ball mill speed. Preliminary laboratory experiments determined that the mass ratio of ceramic balls to steel balls in the mixed grinding media was 5:5, and the single grinding media loading regime was Φ30mm:Φ25mm:Φ20mm = 50%:30%:20%, with a grinding concentration of 67%. During the modification test, the initial target filling rate of the ball mill mixed grinding media was set to 36%. After stable operation, images of the grinding media movement trajectory at the ball mill discharge port were collected. Two consecutive ball replenishment tests were then conducted, with 300kg of ceramic balls and 500kg of steel balls added. After each stable operation, images of the media movement trajectory were collected. Based on the grinding media movement trajectory images at the ball mill discharge port determined by the three filling rates, the ore flow rate was set to 320t / h. Field production experience confirmed that the filling rate range with better grinding effect was 37%-39%. Under the three filling rates corresponding to the field test, particle parameters and equipment material parameters were calibrated through simulation tests. The simulation parameters were adjusted to match the trajectory, and subsequent simulation tests were conducted based on the calibrated parameters.

[0050] Table 1

[0051]

[0052] Step S2: Adjust the grinding conditions of the ball mill and conduct simulation tests under different grinding conditions; conduct simulation tests with the filling rate as a variable, collect the changes in the media movement trajectory at the overflow weir baffle of the ball mill discharge port under different filling rates, and draw images of the grinding media movement trajectory corresponding to different filling rates under specific working conditions to construct a grinding media movement trajectory database; the distribution diagram of grinding media movement trajectories corresponding to different filling rates in Example 1 is shown below. Figure 2-3 As shown.

[0053] Step S3: Based on the real-time images of the grinding media movement trajectory at the ball mill discharge port collected during the on-site production process, and combined with the current working conditions, compare the grinding media movement trajectory images under different working conditions in the grinding media movement trajectory database, and determine the actual filling rate in the ball mill through calibration.

[0054] Example 2:

[0055] Step S1: A modification experiment was conducted on a Ф3600×6000mm overflow ball mill, a two-stage ball mill in a certain factory. Preliminary preparations included determining the shape and distribution of the liner based on actual operating conditions, further establishing a model based on the internal shape of the ball mill (mill speed 17.2 r / min), and setting simulation parameters based on the material properties of the steel balls, ceramic balls, ore, and liner. Magnetic liners were used. Particle parameters were set based on the material properties of the grinding media and ore used in the ball mill. Equipment material parameters and operating modes were set based on the material properties of the liner and the ball mill speed. Preliminary laboratory experiments determined the optimal mass ratio of ceramic balls to steel balls to be 5:5. The ceramic ball loading ratio was Φ30mm:Φ25mm:Φ20mm = 50%:30%:20%, and the steel ball loading ratio was Φ30mm:Φ25mm:Φ20mm = 20%:30%:50%, with a grinding concentration of 67%. During the modification test, the initial target ball filling rate of the ball mill's mixed grinding media was set to 36%. After stable operation, images of the grinding media's movement trajectory at the ball mill discharge port were collected. Two consecutive ball replenishment tests were then conducted. The ball replenishment amount was 240 kg of ceramic balls and 400 kg of steel balls. After each stable operation, the movement trajectory image of the grinding media was collected. Based on the movement trajectory image of the grinding media at the discharge port of the ball mill determined by three filling rates, the ore flow rate was set to 260 t / h. The filling rate range with better grinding effect was confirmed by field production experience to be 37%-39%. Under the three filling rates corresponding to the field test, the particle parameters and equipment material parameters were calibrated by simulation test. The simulation parameters were adjusted to match the trajectory, and subsequent simulation tests were carried out based on the calibrated parameters.

[0056] Table 2

[0057]

[0058] Step S2: Adjust the grinding conditions of the ball mill and conduct simulation tests under different grinding conditions; conduct simulation tests with the filling rate as a variable, collect the changes in the movement trajectory of the grinding media at the overflow weir baffle of the ball mill discharge port under different filling rates, and draw the grinding media movement trajectory images corresponding to different filling rates under specific working conditions to construct a grinding media movement trajectory database; the grinding media movement trajectory diagrams corresponding to different filling rates in Example 2 are shown below. Figure 4-5 As shown.

[0059] Step S3: Based on the real-time images of the grinding media movement trajectory at the ball mill discharge port collected during the on-site production process, and combined with the current working conditions, compare the grinding media movement trajectory images under different working conditions in the grinding media movement trajectory database, and determine the actual filling rate in the ball mill through calibration.

[0060] Example 3:

[0061] Step S1: A modification experiment was conducted on a Ф4500×6400mm overflow ball mill, a two-stage ball mill in a certain factory. Preliminary preparations included determining the shape and distribution of the liner based on actual operating conditions, further establishing a model based on the internal shape of the ball mill (mill speed 15.7 r / min), and setting simulation parameters based on the material properties of the steel balls, ceramic balls, ore, and liner. Magnetic liners were used. Particle parameters were set based on the material properties of the grinding media and ore used in the ball mill. Equipment material parameters and operating modes were set based on the material properties of the liner and the ball mill speed. Preliminary laboratory experiments determined the optimal mass ratio of ceramic balls to steel balls to be 5:5. The ceramic ball loading ratio was Φ30mm:Φ25mm:Φ20mm = 20%:30%:50%, and the steel ball loading ratio was Φ25mm:Φ20mm:Φ15mm = 30%:40%:30%, with a grinding concentration of 75%. During the modification test, the initial target ball filling rate of the ball mill mixed grinding media was set to 36%. After stable operation, images of the grinding media movement trajectory at the ball mill discharge port were collected. Two consecutive ball replenishment tests were then conducted. The ball replenishment amount was 300 kg of ceramic balls and 500 kg of steel balls. After each stable operation, the movement trajectory image of the grinding media was collected. Based on the movement trajectory image of the grinding media at the discharge port of the ball mill determined by three filling rates, the ore flow rate was set to 300 t / h. The filling rate range with better grinding effect was confirmed by field production experience to be 37%-39%. Under the three filling rates corresponding to the field test, the particle parameters and equipment material parameters were calibrated by simulation test. The simulation parameters were adjusted to match the trajectory, and subsequent simulation tests were carried out based on the calibrated parameters.

[0062] Table 3

[0063]

[0064] Step S2: Adjust the grinding conditions of the ball mill and conduct simulation tests under different grinding conditions; conduct simulation tests with the filling rate as a variable, collect the changes in the media movement trajectory at the overflow weir baffle of the ball mill discharge port under different filling rates, and plot the grinding media movement trajectory images corresponding to different filling rates under specific working conditions to construct a grinding media movement trajectory database; the grinding media movement trajectory diagrams corresponding to different filling rates in Example 3 are shown below. Figure 6-7 As shown.

[0065] Step S3: Based on the real-time images of the grinding media movement trajectory at the ball mill discharge port collected during the on-site production process, and combined with the current working conditions, compare the grinding media movement trajectory images under different working conditions in the grinding media movement trajectory database, and determine the actual filling rate in the ball mill through calibration.

[0066] The above are merely specific embodiments of the present invention. It should be noted that any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention. Any other aspects not described in detail are prior art.

Claims

1. A method for calibrating the filling rate of a ball mill based on DEM, characterized in that: Includes the following steps: S1: Determine simulation parameters based on actual working conditions and build a simulation environment in EDEM software; S2: Adjust the grinding conditions of the ball mill and conduct simulation tests under different grinding conditions; The changes in the grinding media trajectory at the overflow weir baffle of the ball mill discharge port were statistically analyzed under different grinding conditions. Images of the grinding media trajectory under different grinding conditions were plotted. Combined with the grinding media trajectory images measured under different working conditions in actual production, a grinding media trajectory database was constructed. S3: Based on the real-time images of the grinding media movement trajectory at the overflow weir baffle of the ball mill discharge port, combined with the current working conditions, and compared with the grinding media movement trajectory images under different working conditions in the grinding media movement trajectory database, the current internal filling rate of the ball mill is obtained through calibration.

2. The ball mill filling rate calibration method based on DEM according to claim 1, characterized in that: Step S1 specifically includes the following methods: S11: Obtain ball mill parameters, including: ball mill model and speed, type and proportion of grinding media used, type of liner used and its appearance after installation; S12: In 3D modeling software, construct a 3D model based on the ball mill model and the shape of the liner after installation; S13: In the EDEM software, set the particle parameters based on the material properties of the grinding media and ore used in the ball mill, and set the equipment material parameters and operating mode based on the material properties of the liner and the ball mill speed. S14: Conduct calibration tests based on the on-site production environment, and conduct subsequent simulation tests based on the parameters calibrated by the calibration tests.

3. The ball mill filling rate calibration method based on DEM according to claim 2, characterized in that: Step S14 specifically includes the following methods: S141: Empty the inside of the ball mill, load it with grinding media of known filling ratio, and conduct trial operation; when it is stable, collect images of the movement trajectory of the grinding media at the ball mill discharge port and record the corresponding operating information. S142: Then, two consecutive ball replenishment tests were conducted. After each test, images of the grinding media movement trajectory at the ball mill discharge port were collected after the operation stabilized, and the operating condition information was recorded. S143: Using the ball mill discharge port grinding media motion trajectory image determined by three known filling rates as a benchmark, the particle parameters and equipment material parameters in step S13 are calibrated by conducting simulation tests, and subsequent simulation tests are conducted based on the calibrated parameters.

4. The ball mill filling rate calibration method based on DEM according to claim 1, 2, or 3, characterized in that: In step S2, adjusting the grinding conditions of the ball mill includes adjusting the mass ratio of grinding media, ball loading system, filling rate, ore quantity, or grinding concentration within the ball mill.

5. The ball mill filling rate calibration method based on DEM according to claim 4, characterized in that: The ball mill is a horizontal overflow ball mill.

6. The ball mill filling rate calibration method based on DEM according to claim 4, characterized in that: The grinding media include steel balls and ceramic balls.

7. The ball mill filling rate calibration method based on DEM according to claim 4, characterized in that: The ball loading regime of the grinding media is Φ30mm:Φ25mm:Φ20mm = 20%~50%: 20%~30%: 20%~50%.

8. The ball mill filling rate calibration method based on DEM according to claim 4, characterized in that: The filling rate of the grinding media is 32% to 45%.

9. The ball mill filling rate calibration method based on DEM according to claim 4, characterized in that: The amount of ore in the grinding media is 260t / h to 400t / h.

10. The ball mill filling rate calibration method based on DEM according to claim 4, characterized in that: The grinding concentration of the grinding media is 65% to 70%.

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