DEM-based ball mill filling rate calibration method

Abstract

The invention discloses a DEM-based ball mill filling rate calibration method, which comprises the following steps of S1, determining simulation parameters based on actual working conditions, and constructing a simulation environment in EDEM software; s2, adjusting the ore grinding conditions of the ball mill, and performing a simulation test under different ore grinding conditions; counting the movement track change conditions of the ore grinding medium at the overflow weir baffle at the ore discharge port of the ball mill under different ore grinding conditions, and constructing an ore grinding medium movement track database; and S3, according to the ore grinding medium motion trail images, collected in real time on site, at the overflow weir baffle of the ore discharge port of the ball mill, the current working condition is combined, the ore grinding medium motion trail images under different working conditions in the ore grinding medium motion trail database are compared, and the current internal filling rate of the ball mill is obtained through calibration. According to the invention, high-precision and real-time monitoring of the internal filling rate of the ball mill with the mixed ore grinding medium during operation can be realized, and the continuous and stable capability of the production process can be maintained, so that the overall efficiency and the product quality are promoted to be improved.

Description

Technical Field

[0001] The invention relates to the technical field of ore grinding, and in particular to a ball mill filling rate calibration method based on DEM. Background Art

[0002] Ball mill plays a vital role in the field of mineral processing and is an indispensable core equipment in the mineral processing process. It uses grinding media to grind the ore to achieve full separation of the effective components and gangue in the ore. This process not only improves the dissociation degree of the mineral, but also enhances the efficiency of subsequent separation operations, such as flotation, magnetic separation or gravity separation, thereby improving the recovery rate and economic benefits of the entire 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, capable of real-time monitoring and adjustment of operating parameters to optimize production efficiency, experience still plays an important role in the setting of specific operating parameters. This is mainly because the ball milling process is complex and involves the interaction of multiple factors such as material properties, mill structure, grinding media type, ball mill filling rate, rotation speed, power consumption, etc.

[0004] Under the general background of reducing grinding energy consumption in mineral processing plants, achieving cost reduction and efficiency improvement, energy conservation and consumption reduction, and achieving the goals of carbon peak 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 used in mineral processing plants; compared with the use of a single ball milling medium, the use of ceramic balls + steel balls mixed ball milling media for grinding has a stronger demand for 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 adding mode. Summary of the invention

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

[0006] To achieve the above object, the present invention provides a ball mill filling rate calibration method based on DEM, 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 motion trajectory of the grinding medium at the overflow weir baffle of the ball mill discharge port under different grinding conditions, draw images of the motion trajectory of the grinding medium under different grinding conditions, and build a database of the motion trajectory of the grinding medium in combination with the images of the motion trajectory of the grinding medium measured under different working conditions in actual production;

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

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

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

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

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

[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, the step S14 specifically includes the following method:

[0016] S141: Empty the interior of the ball mill, load the grinding medium with a known filling rate, and conduct a trial run; when the ball mill is stable, collect the movement trajectory image of the grinding medium at the discharge port of the ball mill, and record the corresponding working condition information;

[0017] S142: Then, two consecutive ball supplementation tests are performed, and each time after the operation is stable, the movement trajectory image of the grinding medium at the discharge port of the ball mill is collected, and the working condition information is recorded;

[0018] S143: Based on the images of the grinding medium motion trajectory at the ball mill discharge port determined by three known filling rates, the particle parameters and equipment material parameters in step S13 are calibrated by performing simulation tests, and subsequent simulation tests are performed based on the calibrated parameters.

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

[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 filling system of the grinding medium is Φ30mm:Φ25mm:Φ20mm=20%~50%:20%~30%:20%~50%.

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

[0024] Furthermore, the ore capacity of the grinding medium is 260 t / h to 400 t / h.

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

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

[0027] Firstly, compared with the prior art method of purely relying on grinding effect and experience to determine the amount of balls to be added, the DEM-based ball mill filling rate calibration method of the present invention is based on the necessary modification of the ball mill discharge port when the ball mill uses ceramic balls, namely, the overflow weir baffle structure of the ball mill discharge port. A method of calibrating the current filling rate inside the ball mill by observing the movement trajectory of the grinding medium at the ball mill discharge port is proposed, thereby providing guidance for determining the detailed amount of balls to be added under different working conditions during on-site production, so as to stabilize the ball mill production at a specific optimal value, improve work efficiency, and further increase economic benefits.

[0028] Secondly, the DEM-based ball mill filling rate calibration method of the present invention innovatively introduces a new filling rate calibration strategy, which analyzes the movement path of the grinding medium on the baffle surface at the rear of the ball mill, thereby realizing high-precision and real-time monitoring of the internal filling rate of the ball mill with ceramic balls + steel balls as mixed grinding media during operation, which is beneficial to maintaining the continuous and stable ability of the production process, thereby promoting the improvement of overall efficiency and product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the process of a ball mill filling rate calibration method based on DEM;

[0030] Figure 2 This is a schematic diagram of a window for observing the movement trajectory of grinding media corresponding to different filling rates during the simulation process of Example 1 of the present invention;

[0031] Figure 3 The distribution diagram of the movement trajectory of the grinding media corresponding to different filling rates in Example 1 of the present invention;

[0032] Figure 4 This is a schematic diagram of a window for observing the movement trajectory of grinding media corresponding to different filling rates during the simulation process of Example 2 of the present invention;

[0033] Figure 5 The distribution diagram of the movement trajectory of the grinding media corresponding to different filling rates in Example 2 of the present invention;

[0034] Figure 6 This is a schematic diagram of a window for observing the movement trajectory of grinding media corresponding to different filling rates during the simulation process of Example 3 of the present invention;

[0035] Figure 7 This is a distribution diagram of the movement trajectories of the grinding media corresponding to different filling rates in Example 3 of the present invention. DETAILED DESCRIPTION

[0036] The following is a detailed description of the implementation of the present invention in conjunction with the implementation cases, but they do not constitute a limitation of the present invention and are only given as examples. At the same time, the advantages of the present invention will become clearer and easier to understand through the description.

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

[0038] Step S1: Determine simulation parameters based on actual working conditions and build a simulation environment in EDEM software; specifically, the following steps are included:

[0039] S11: Obtain the parameters of the ball mill, including: ball mill model and rotation speed, type and proportion of grinding media used, type of liner used and its shape after installation.

[0040] S12: In a 3D modeling software (solidworks or 3dsmax), a 3D model is constructed based on the ball mill model and the shape of the liner after installation.

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

[0042] S14: Perform calibration tests based on the on-site production environment. The specific steps include:

[0043] S141: Empty the interior of the ball mill, load the grinding medium with a known filling rate, and conduct a trial run; when the ball mill is stable, collect the movement trajectory image of the grinding medium at the discharge port of the ball mill, and record the corresponding working condition information;

[0044] S142: Then, two consecutive ball supplement tests are performed, and each time, after the operation is stable, the medium motion trajectory image is collected and the working condition information is recorded;

[0045] S143: Based on the images of the grinding medium motion trajectory at the ball mill discharge port determined by three known filling rates, the particle parameters and equipment material parameters in step S13 are calibrated by performing simulation tests, and subsequent simulation tests are performed based on the calibrated parameters.

[0046] Step S2: referring to the previous laboratory experimental results and the on-site working conditions, the grinding conditions of the grinding medium mass ratio, ball loading system, filling rate, ore amount or grinding concentration in the ball mill are changed to conduct a simulation test; the grinding medium in the ball mill mainly includes steel balls and ceramic balls, and the grinding medium mass ratio is steel balls: ceramic balls = 1:9-7:3; the single grinding medium loading system is Φ30mm:Φ25mm:Φ20mm=20%-50%:20%-30%:20%-50%; the filling rate is 32%-45%, the ore amount is 260t / h-400t / h, and the grinding concentration is 65%-75%; observe and count the changes in the medium motion trajectory at the overflow weir baffle of the discharge port under different parameters, draw the medium motion trajectory images under different conditions, and combine the medium motion trajectory images measured under different working conditions in actual production to construct a medium motion trajectory database.

[0047] Step S3: Based on the real-time on-site collected grinding medium motion trajectory image at the ball mill discharge port, combined with the current working conditions, the grinding medium motion trajectory images under different working conditions in the existing database are compared to obtain the current filling rate in the ball mill.

[0048] Embodiment 1:

[0049] Step S1: A transformation test was conducted on a second-stage ball mill of a certain factory, which was a 4270×7300 overflow ball mill. The preliminary preparation included determining the shape and distribution of the liner based on the actual working conditions, and further establishing a model based on the internal shape of the ball mill. The ball mill speed was 15.7r / min, and the simulation parameters were set according to the material characteristic parameters of the steel balls, ceramic balls, ores and liner plates. The liner plates used were manganese steel liner plates. The particle parameters were set based on the material characteristic parameters of the grinding media and ore used in the ball mill, and the equipment material parameters and operation mode were set based on the material characteristic parameters of the liner plates used and the ball mill speed. Preliminary laboratory experiments determined that the mass ratio of ceramic balls and steel balls for mixed loading was 5:5, the loading system of single grinding media was Φ30mm:Φ25mm:Φ20mm=50%:30%:20%, and the grinding concentration was 67%; during the transformation test, the target filling rate of the initial loading of the mixed grinding media of the ball mill was set to 36%, and the motion trajectory image of the grinding media at the ball mill discharge port was collected after stable operation; then two consecutive ball replenishment tests were carried out, with the ball replenishment amount of 300kg of ceramic balls and 500kg of steel balls, and the media motion trajectory image was collected each time after stable operation; based on the motion trajectory image of the grinding media at the ball mill discharge port determined by the three filling rates, the ore volume was set to 320t / h, and the filling rate range with better grinding effect was confirmed by field production experience to be 37%-39%; at the three filling rates corresponding to the field test, the 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 carried out based on the calibrated parameters.

[0050] Table 1

[0051]

[0052] Step S2: adjusting the grinding conditions of the ball mill, and conducting simulation tests under different grinding conditions; conducting simulation tests with the filling rate as a variable, collecting the changes in the medium motion trajectory at the overflow weir baffle of the ball mill discharge port under different filling rates, drawing the grinding medium motion trajectory images corresponding to different filling rates under specific working conditions, and constructing a grinding medium motion trajectory database; the grinding medium motion trajectory distribution diagram corresponding to different filling rates in Example 1 is shown in FIG. Figure 2-3 shown.

[0053] Step S3: Based on the grinding medium motion trajectory image of the ball mill discharge port collected in real time during the on-site production process, combined with the current working conditions, the grinding medium motion trajectory images under different working conditions in the grinding medium motion trajectory database are compared, and the actual filling rate in the current ball mill is obtained through calibration.

[0054] Embodiment 2:

[0055] Step S1: A transformation experiment was conducted on a second-stage ball mill of a factory with a model of Ф3600×6000mm overflow ball mill. Preliminary preparations included determining the shape and distribution of the liner based on actual working conditions, and further establishing a model based on the internal shape of the ball mill. The ball mill speed was 17.2r / min, and simulation parameters were set according to the material characteristic parameters of steel balls, ceramic balls, ores and liner plates. The liner plates used were magnetic liner plates. The particle parameters were set based on the material characteristic parameters of the grinding media and ore used in the ball mill, and the equipment material parameters and operation mode were set based on the material characteristic parameters of the liner plates used and the ball mill speed. The preliminary laboratory experiments determined that the mass ratio of ceramic balls and steel balls was 5:5, the ceramic ball loading system was Φ30mm:Φ25mm:Φ20mm=50%:30%:20%, the steel ball loading system was Φ30mm:Φ25mm:Φ20mm=20%:30%:50%, and the grinding concentration was 67%. During the transformation test, the target filling rate of the initial mixed grinding medium of the ball mill was set to 36%. After the operation was stable, the movement trajectory image of the grinding medium at the discharge port of the ball mill was collected. Then two consecutive ball supplementation tests were carried out. The amount of supplementary balls is 240kg of ceramic balls and 400kg of steel balls. The medium motion trajectory image is collected each time after the operation is stable. The ore capacity is set to 260t / h based on the grinding medium motion trajectory image at the ball mill discharge port determined by three filling rates. The filling rate range with better grinding effect is confirmed to be 37%-39% based on field production experience. Under the three filling rates corresponding to the field test, the particle parameters and equipment material parameters are calibrated through simulation tests, the simulation parameters are adjusted to match the trajectory, and subsequent simulation tests are carried out based on the calibrated parameters.

[0056] Table 2

[0057]

[0058] Step S2: adjusting the grinding conditions of the ball mill, and conducting simulation tests under different grinding conditions; conducting simulation tests with the filling rate as a variable, collecting the changes in the medium motion trajectory at the overflow weir baffle of the ball mill discharge port under different filling rates, and drawing the grinding medium motion trajectory images corresponding to different filling rates under specific working conditions, and constructing a grinding medium motion trajectory database; the grinding medium motion trajectory images corresponding to different filling rates in Example 2 are as follows Figure 4-5 shown.

[0059] Step S3: Based on the grinding medium motion trajectory image of the ball mill discharge port collected in real time during the on-site production process, combined with the current working conditions, the grinding medium motion trajectory images under different working conditions in the grinding medium motion trajectory database are compared, and the actual filling rate in the current ball mill is obtained through calibration.

[0060] Embodiment 3:

[0061] Step S1: A transformation experiment was conducted on a second-stage ball mill of a factory with a model of Ф4500×6400mm overflow ball mill. The preliminary preparation includes determining the shape and distribution of the liner based on the actual working conditions, and further establishing a model based on the internal shape of the ball mill. The ball mill speed is 15.7r / min, and the simulation parameters are set according to the material characteristic parameters of the steel balls, ceramic balls, ores and liner. The liner used is a magnetic liner. The particle parameters are set based on the material characteristic parameters of the grinding media and ore used in the ball mill, and the equipment material parameters and operation mode are set based on the material characteristic parameters of the liner used and the ball mill speed. The preliminary laboratory experiments determined that the mass ratio of ceramic balls and steel balls was 5:5, the ceramic ball loading system was Φ30mm:Φ25mm:Φ20mm=20%:30%:50%, the steel ball loading system was Φ25mm:Φ20mm:Φ15mm=30%:40%:30%, and the grinding concentration was 75%. During the transformation test, the target filling rate of the initial mixed grinding medium of the ball mill was set to 36%. After the operation was stable, the movement trajectory image of the grinding medium at the discharge port of the ball mill was collected. Then two consecutive ball supplementation tests were carried out. The ball replenishment amount is 300kg of ceramic balls and 500kg of steel balls. The medium motion trajectory image is collected each time after the operation is stable. The ore capacity is set to 300t / h based on the grinding medium motion trajectory image at the ball mill discharge port determined by three filling rates. The field production experience confirms that the filling rate range with better grinding effect is 37%-39%. Under the three filling rates corresponding to the field test, the particle parameters and equipment material parameters are calibrated through simulation tests, the simulation parameters are adjusted to match the trajectory, and subsequent simulation tests are carried out based on the calibrated parameters.

[0062] Table 3

[0063]

[0064] Step S2: adjusting the grinding conditions of the ball mill, and conducting simulation tests under different grinding conditions; conducting simulation tests with the filling rate as a variable, collecting the changes in the medium motion trajectory at the overflow weir baffle of the ball mill discharge port under different filling rates, and drawing the grinding medium motion trajectory images corresponding to different filling rates under specific working conditions, and constructing a grinding medium motion trajectory database; the grinding medium motion trajectory images corresponding to different filling rates in Example 3 are shown in FIG. Figure 6-7 shown.

[0065] Step S3: Based on the grinding medium motion trajectory image of the ball mill discharge port collected in real time during the on-site production process, combined with the current working conditions, the grinding medium motion trajectory images under different working conditions in the grinding medium motion trajectory database are compared, and the actual filling rate in the current ball mill is obtained through calibration.

[0066] The above are only specific embodiments of the present invention. It should be pointed out that any changes or substitutions that can be easily thought of by any technician familiar with the field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. The rest not described in detail are prior arts.

Claims

1. A ball mill filling rate calibration method based on DEM, characterized in that: The steps include: 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; Statistics on the changes in the motion trajectory of the grinding medium at the overflow weir baffle of the ball mill discharge port under different grinding conditions, draw images of the motion trajectory of the grinding medium under different grinding conditions, and build a database of the motion trajectory of the grinding medium based on the images of the motion trajectory of the grinding medium measured under different working conditions in actual production; S3: Based on the real-time collected on-site grinding medium motion trajectory image at the overflow weir baffle of the ball mill discharge port, combined with the current working conditions, the grinding medium motion trajectory images under different working conditions in the grinding medium motion trajectory database are compared, and the current ball mill internal filling rate is obtained through calibration.

2. The ball mill filling rate calibration method based on DEM according to claim 1, characterized in that: The step S1 specifically includes the following method: S11: Obtaining ball mill parameters, including: ball mill model and speed, type and proportion of grinding media used, type of liner used and shape after installation; S12: In the 3D modeling software, a 3D model is constructed based on the ball mill model and the shape of the liner after installation; S13: In the EDEM software, the particle parameters are set based on the material characteristic parameters of the grinding media and ore used in the ball mill, and the equipment material parameters and operation mode are set based on the material characteristic parameters of the liner used and the speed of the ball mill; 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: The step S14 specifically includes the following method: S141: Empty the interior of the ball mill, load the grinding medium with a known filling rate, and conduct a trial run; when the ball mill is stable, collect the movement trajectory image of the grinding medium at the discharge port of the ball mill, and record the corresponding working condition information; S142: Then, two consecutive ball supplementation tests are performed, and each time after the operation is stable, the movement trajectory image of the grinding medium at the discharge port of the ball mill is collected, and the working condition information is recorded; S143: Based on the images of the grinding medium motion trajectory at the ball mill discharge port determined by three known filling rates, the particle parameters and equipment material parameters in step S13 are calibrated by performing simulation tests, and subsequent simulation tests are performed 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 the step S2, adjusting the grinding conditions of the ball mill includes adjusting the mass ratio of the grinding media in the ball mill, the ball loading system, the filling rate, the ore amount or the grinding concentration.

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 filling system of the grinding medium 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 medium is 32% to 45%.

9. The ball mill filling rate calibration method based on DEM according to claim 4, characterized in that: The ore capacity of the grinding medium is 260 t / h to 400 t / 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 medium is 65% to 70%.

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