A design method for the liner with equal service life for the semi-autogenous grinding mill cylinder

Abstract

The present invention discloses a method for designing liners of equal life for a semi-autogenous mill barrel, comprising the following steps: conducting mechanical property tests and crushing experiments on ore, steel balls and liners to obtain corresponding mechanical property and crushing characteristic parameters; establishing an ore crushing model and a medium particle model based on the discrete element method using the Tavares crushing model; establishing a three-dimensional model of the semi-autogenous mill using SOLIDWORKS software to divide the semi-autogenous mill barrel liner into regions along the axial and radial directions; using the Archard wear model to obtain the wear volume of different regions in the axial and radial directions, and redistributing the liner volume of each region based on the simulated wear volume to design liners of equal life. The present invention adopts the above-mentioned method for designing liners of equal life for a semi-autogenous mill barrel to reduce the uneven degree of axial wear of the semi-autogenous mill liner, extend the overall life of the liner, improve the utilization rate of the liner steel, improve the working efficiency of the semi-autogenous mill, and reduce the cost of mineral processing.

Description

Technical Field

[0001] The invention relates to the technical field of mineral processing engineering, in particular to a design method for a semi-autogenous mill barrel isochronous liner. Background Art

[0002] The SAG mill liner serves to lift the material and grinding media, while also protecting the mill cylinder from impact. During operation, the mill liner is subject to wear and impact from the material and grinding media, necessitating regular mill shutdowns for inspection and liner replacement to prevent wear. SAG mill liner replacement and unplanned mill shutdowns significantly impact the mill's production efficiency. Improving liner life is crucial to improving mill profitability.

[0003] In existing technology, mineral processing practitioners primarily increase liner life by using wear-resistant materials and selecting appropriate liner structural parameters. These two methods have improved liner life to a certain extent. However, during the actual operation of a semi-autogenous grinding mill, due to the presence of end liners at both the inlet and outlet ends, the material and grinding media are unevenly distributed along the axial direction of the cylinder liner. This results in different wear effects of the material and grinding media on the cylinder liner, causing uneven axial wear of the liner, ultimately leading to localized excessive wear and failure of the liner. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for designing a liner with an equal life span for a semi-autogenous mill barrel, thereby reducing the uneven degree of axial wear of the liner of the semi-autogenous mill, extending the overall life of the liner without significantly increasing the mass of the liner, improving the utilization rate of the liner steel, improving the efficiency of the mineral processing operation, and reducing the mineral processing cost.

[0005] To achieve the above object, the present invention provides a method for designing a liner with an equal life span for a semi-autogenous mill cylinder, comprising the following steps:

[0006] S1. Obtain the mechanical properties of the ore, liner, and steel ball through uniaxial compression testing, drainage method, and strain testing system, where the mechanical properties include elastic modulus, shear modulus, density, and Poisson's ratio;

[0007] S2. Perform a single-particle crushing experiment on the ore using a falling-weight crushing device to obtain crushing characteristic parameters, wherein the crushing characteristic parameters include damage accumulation constant, fitting parameter, fracture energy standard deviation, minimum crushing size, minimum collision energy, and tangential energy ratio;

[0008] S3. Obtain contact coefficients using the inclined plate test, cylinder lifting test, and rockfall impact test, where the contact coefficients include the static friction coefficient, rolling friction coefficient, and restitution coefficient;

[0009] S4. Use SOLIDWORKS software to build a 3D solid model of the SAG mill and divide the cylinder liner into zones along the axial direction;

[0010] S5. Divide each regional liner into regions according to the radial direction and establish a discrete element simulation model;

[0011] S6. Determine the normal operating status and parameters of the SAG mill;

[0012] S7. Perform particle size screening on the feed to the SAG mill to determine the particle size distribution of the feed ore medium;

[0013] S8. Input the mechanical properties, crushing characteristic parameters and contact parameters of the ore, steel ball and liner obtained in S1, S2 and S3 into the discrete element software, use the Tavares crushing model to establish the ore crushing model, medium particle model and discrete element contact model, and import the discrete element simulation model into the discrete element software;

[0014] S9. Based on the discrete element method, using the Archard wear model, discrete element simulation is performed to obtain the axial wear volume of the liner according to the divided axial direction area; according to the divided radial direction area, the radial area wear volume of the liner in different axial areas is obtained;

[0015] S10. Redistribute the axial volume of the liner according to the obtained axial wear volume;

[0016] S11. Redistribute the liner volume in each radial area according to the liner wear volume in the radial area and the liner volume in each area after redistribution;

[0017] S12. Design lining plates with equal service life according to the lining plate volumes in different areas.

[0018] Preferably, in S4, the three-dimensional solid model of the entire semi-autogenous mill includes: a feed trolley, a guide trough, a feed end cover, a cylinder liner, a discharge cover end, and a lifter. The feed trolley is used to simulate the feeding process of the semi-autogenous mill, the feed end cover is used to simulate the feeding process of the semi-autogenous mill, the cylinder liner is used to simulate the ore crushing process of the semi-autogenous mill, and the discharge end cover and the lifter are used to simulate the discharging process of the semi-autogenous mill.

[0019] Preferably, in S6, the normal operating state and parameters of the SAG mill include: SAG mill speed, comprehensive filling rate, ore filling rate, and steel ball filling rate.

[0020] Preferably, in S7, the feed to the semi-autogenous mill is subjected to particle size screening, different particle size names are defined according to the size of the ore medium of the feed, and the yield and cumulative yield of different particle sizes are obtained.

[0021] Preferably, in S8, the discrete element software is EDEM software, and the rotation rate, comprehensive filling rate, ore filling rate, and steel ball filling rate are set according to the operating status and parameters of the semi-autogenous mill; the feed rate and feed particle size are set according to the ore particle size distribution.

[0022] Preferably, in S9, the wear volume calculation formula in the Archard wear model is:

[0023] Q=WF n S

[0024] Where Q is the volume wear, W is the wear constant, F n is the normal force, and S is the tangential displacement.

[0025] Preferably, in S10, the volume of the liner in the axial direction is redistributed, and the distribution formula is as follows:

[0026]

[0027] Where n is the number of axial division areas, V i V is the volume of each liner after redistribution, initial is the total volume of the initial liner, C is the mass ratio of the redesigned liner to the initial liner, where V i Satisfy the following formula:

[0028]

[0029] Among them, l i is the length of region i, Q i is the axial volume wear of region i.

[0030] Preferably, in S11, the liner volume of each radial region is redistributed, and the distribution formula is as follows:

[0031]

[0032] Where t is the number of radially divided regions, V s is the volume of the Sth axial region, is the volume of the i-th radial region of the S-th axial region after redistribution, where Satisfy the following formula:

[0033]

[0034] in, is the wear volume of the i-th radial region in the S-th axial region.

[0035] Therefore, the present invention adopts the above-mentioned method for designing the liner of the semi-autogenous mill cylinder with the same life span, and the beneficial effects are as follows:

[0036] (1) The present invention prolongs the overall service life of the liner without significantly increasing the mass of the liner.

[0037] (2) The present invention improves the utilization rate of liner steel, improves the efficiency of mineral processing operations, and reduces mineral processing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the working process of an embodiment of a method for designing a liner of a semi-autogenous mill barrel with equal life span according to the present invention;

[0039] Figure 2 Schematic diagram of a three-dimensional solid model of a semi-autogenous mill according to an embodiment of a method for designing a liner for a semi-autogenous mill cylinder of the present invention;

[0040] Figure 3 Schematic diagram of an initial cylinder liner model according to an embodiment of a method for designing a cylinder liner of a semi-autogenous mill having an equal life span according to the present invention;

[0041] Figure 4 Schematic diagram of the axial division of a cylinder liner model according to an embodiment of a method for designing a cylinder liner of a semi-autogenous mill of the present invention;

[0042] Figure 5 Schematic diagram of the radial division of a cylinder liner model according to an embodiment of a method for designing a cylinder liner of a semi-autogenous mill of the present invention;

[0043] Figure 6 Schematic diagram of the axial wear volume of the liner according to an embodiment of a method for designing a liner having an equal life span for a semi-autogenous mill barrel according to the present invention;

[0044] Figure 7 The wear volume of liners in different radial regions of each axial region of an embodiment of a method for designing liners for equal life of a semi-autogenous mill barrel of the present invention;

[0045] Figure 8 The invention discloses a liner model of equal life designed in accordance with an embodiment of a method for designing a liner of equal life for a semi-autogenous mill cylinder.

[0046] Reference numerals

[0047] 1. Feed trolley; 2. Material guide chute; 3. Feed end cover; 4. Cylinder lining; 5. Discharge end cover; 6. Lifter. DETAILED DESCRIPTION

[0048] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0049] Unless otherwise defined, technical or scientific terms used in the present invention shall have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0050] Example 1

[0051] like Figure 1 As shown, a method for designing a liner with an equal life span for a semi-autogenous mill cylinder includes the following steps:

[0052] S1. Use an electro-hydraulic servo universal testing machine to perform uniaxial compression tests on the ore, liner, and steel ball to obtain the elastic modulus and shear modulus; use the water displacement method to measure the density of the ore, liner, and steel ball; and use a strain testing system to measure the Poisson's ratio of the ore, liner, and steel ball.

[0053] S2. Use falling weight crushing equipment to conduct single particle crushing test on ore and measure the ore crushing characteristic parameters.

[0054] S3. Use the inclined plate test and the cylinder lifting test to measure the static friction coefficient and the rolling friction coefficient; use the rockfall impact test to measure the restitution coefficient.

[0055] According to the obtained ore mechanical property parameters, crushing characteristic parameters, mechanical parameters of steel balls and liner, and contact parameters, as shown in Tables 1 and 2, the ore crushing model, medium particle model, and discrete element contact model were established.

[0056] Table 1 Mechanical properties and contact parameters of ore, steel ball and liner

[0057] parameter Numerical unit Steel ball density 7800 <![CDATA[kg / m 3 ]]> Steel ball shear modulus 7.00e+10 Pa Poisson's ratio of steel ball 0.28 - Ore density 3400 <![CDATA[kg / m 3 ]]> Ore shear modulus 2.00e+10 Pa Poisson's ratio of ore 0.23 - Steel ball and steel ball restitution coefficient 0.70 - Static friction coefficient between steel balls 0.20 - Rolling friction coefficient between steel balls 0.01 - Recovery coefficient of steel balls and ore 0.41 - Static friction coefficient between steel ball and ore 0.50 - Rolling friction coefficient between steel ball and ore 0.20 - Ore and Ore Recovery Factor 0.30 - Static friction coefficient between ore and ore 0.60 - Coefficient of rolling friction between ore and ore 0.15 -

[0058] Table 2 Ore crushing characteristic parameters

[0059]

[0060]

[0061] S4, such as Figure 2-Figure 5 As shown, a three-dimensional solid model of the semi-autogenous mill is established, and the liner is divided into multiple areas along the axial direction. In this embodiment, the liner is divided into three areas along the axial direction, named Z01, Z02, and Z03.

[0062] S5. Divide each liner into regions according to the radial direction. In this embodiment, the liner is radially divided into three regions, named R01, R02, and R03. The arrows indicate the rotation direction of the cylinder liner.

[0063] A discrete element simulation model was established, in which the feed trolley 1 and the guide chute 2 were used to simulate the process of transporting ore to the semi-autogenous mill, the feed end cover 3 was used to simulate the feeding process of the semi-autogenous mill, the cylinder liner 4 was used to simulate the ore crushing process of the semi-autogenous mill, and the discharge end cover 5 and the elevator 6 were used to simulate the discharge process of the semi-autogenous mill.

[0064] S6. Determine that when the semi-autogenous grinding mill is operating normally, the speed is 75% of the critical speed, the comprehensive filling rate is 28%, of which steel balls are 11% and ore is 17%, and the maximum diameter of steel balls is 120mm.

[0065] S7. Perform particle size analysis on the feed to the SAG mill to determine the particle size distribution of the feed ore medium, as shown in Table 3.

[0066] Table 3 SAG mill feed particle size

[0067] Particle size name / mm Yield Cumulative yield +150 9.79％ - -150+50 14.87％ 24.66％ -50+20 26.61％ 51.27％ -20 48.73％ 100％

[0068] S8, input the mechanical parameters and contact parameters obtained in S1 and S3 into EDEM software, and use the Tavares crushing model to input relevant crushing characteristic parameters into it;

[0069] Import the 3D solid simulation model of the SAG mill in S4 into EDEM software;

[0070] According to the parameters of the SAG mill during normal operation in S6, the corresponding initial particles are set inside the SAG mill, and the rotation speeds of the feed end 3, the cylinder liner 4, the discharge end cover 5 and the elevator 6 are set;

[0071] A pellet plant is set up in the feed trolley to generate pellets at a rate of 150 kg / s according to the particle size distribution in S7, so that the pellets are fed into the semi-autogenous grinding mill through the feed trolley 1, the guide chute 2, and the material end cover 3.

[0072] The Archard wear model was used, and the wear constant W was set to 1.0×10 -10 , and perform simulation.

[0073] S9. After the simulation is completed, the wear volume of different areas in the axial direction and radial direction of the semi-autogenous grinding mill is obtained according to the areas divided by S4 and S5, such as Figure 5 As shown, the wear volume increases gradually from S01 to S03. Therefore, the liner volume should increase gradually from S01 to S03.

[0074] like Figure 6-Figure 7 As shown, the wear of Z02 and Z03 areas in regions S01 to S03 increases successively, and the wear of Z01 area in regions S02 and S03 is similar, but both are greater than that of S01 area. Moreover, the wear shows a trend that Z03 area is greater than Z02 area, and Z02 area is greater than Z01 area.

[0075] S10, based on the axial wear volume obtained in S9, redistribute the axial volume of the liner, and the distribution formula is as follows;

[0076]

[0077] Where n is the number of axial division areas, V i V is the volume of each liner after redistribution, initial =0.4120m 3 , C is the mass ratio of the redesigned liner to the initial liner, which is 1 here, where V i Satisfy the following formula:

[0078]

[0079] Among them, l i is the length of region i, Q i is the axial volume wear of region i, l i The mass distribution of each axial region can be calculated as follows: V1 = 0.0992m 3 , V2=0.1479m 3 , V3=0.1649m 3 .

[0080] S11. Redistribute the liner volume in each radial region according to the liner wear volume in S9 and the liner volume in each region after redistribution in S10. The distribution formula is as follows:

[0081]

[0082] Where t is the number of radially divided regions; V s is the area of ​​the Sth axial region; is the area of ​​the i-th radial region of the S-th axial region after redistribution, where Satisfy the following formula:

[0083]

[0084] Among them, Q i s is the wear volume of the i-th radial region in the S-th axial region.

[0085] The volume of different radial areas in each axial area can be obtained by calculation:

[0086]

[0087]

[0088] S12, such as Figure 8 As shown in the figure, reasonable liner with equal service life is designed according to the liner volume in different areas of S10 and S11.

[0089] Therefore, the present invention adopts the above-mentioned semi-autogenous mill barrel equal life liner design method, which can obtain the wear of the liner in different areas along the axial direction, and redesign the liner according to the wear conditions, thereby reducing the uneven axial wear without significantly increasing the mass of the liner, extending the service life of the liner, improving the utilization rate of the liner steel, and effectively reducing the production cost of the mineral processing plant.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for designing a liner with equal life span for a semi-autogenous mill cylinder, characterized by: The following steps are involved: S1. Obtain the mechanical properties of the ore, liner, and steel ball through uniaxial compression testing, drainage method, and strain testing system, where the mechanical properties include elastic modulus, shear modulus, density, and Poisson's ratio; S2. Perform a single-particle crushing experiment on the ore using a falling-weight crushing device to obtain crushing characteristic parameters, wherein the crushing characteristic parameters include damage accumulation constant, fitting parameter, fracture energy standard deviation, minimum crushing size, minimum collision energy, and tangential energy ratio; S3. Obtain contact coefficients using the inclined plate test, cylinder lifting test, and rockfall impact test, where the contact coefficients include the static friction coefficient, rolling friction coefficient, and restitution coefficient; S4. Use SOLIDWORKS software to build a 3D solid model of the SAG mill and divide the cylinder liner into zones along the axial direction; S5. Divide each regional liner into regions according to the radial direction and establish a discrete element simulation model; S6. Determine the normal operating status and parameters of the SAG mill; S7. Perform particle size screening on the feed to the SAG mill to determine the particle size distribution of the feed ore medium; S8. Input the mechanical properties, crushing characteristic parameters and contact parameters of the ore, steel ball and liner obtained in S1, S2 and S3 into the discrete element software, use the Tavares crushing model to establish the ore crushing model, medium particle model and discrete element contact model, and import the discrete element simulation model into the discrete element software; S9. Based on the discrete element method, using the Archard wear model, discrete element simulation is performed to obtain the axial wear volume of the liner according to the divided axial direction area; according to the divided radial direction area, the radial area wear volume of the liner in different axial areas is obtained; S10. Redistribute the axial volume of the liner according to the obtained axial wear volume; S11. Redistribute the liner volume in each radial area according to the liner wear volume in the radial area and the liner volume in each area after redistribution; S12. Design lining plates with equal service life according to the lining plate volumes in different areas.

2. The method for designing a liner with an equal life span for a semi-autogenous mill cylinder according to claim 1, characterized in that: In S4, the 3D solid model of the entire SAG mill includes: feed trolley, guide chute, feed end cover, cylinder liner, discharge end cover, and elevator. The feed trolley is used to simulate the feeding process of the SAG mill, the feed end cover is used to simulate the feeding process of the SAG mill, the cylinder liner is used to simulate the ore crushing process of the SAG mill, and the discharge end cover and elevator are used to simulate the discharging process of the SAG mill.

3. The method for designing a liner with equal life span for a semi-autogenous mill cylinder according to claim 1, characterized in that: In S6, the normal operating status and parameters of the SAG mill include: SAG mill speed, comprehensive filling rate, ore filling rate, and steel ball filling rate.

4. The method for designing a liner with an equal life span for a semi-autogenous mill cylinder according to claim 1, characterized in that: In S7, the feed to the semi-autogenous grinding mill is subjected to particle size screening. Different particle size names are defined according to the size of the ore medium fed to the ore, and the yield and cumulative yield of different particle sizes are obtained.

5. The method for designing a liner with equal life span for a semi-autogenous mill cylinder according to claim 3, characterized in that: In S8, the discrete element software is EDEM software. According to the operating status and parameters of the semi-autogenous mill, the rotation rate, comprehensive filling rate, ore filling rate, and steel ball filling rate are set; according to the ore particle size distribution, the feed rate and feed particle size are set.

6. The method for designing a liner with an equal life span for a semi-autogenous mill cylinder according to claim 1, characterized in that: In S9, the wear volume calculation formula in the Archard wear model is: ； in, is the volume wear, is the wear constant, is the normal force, is the tangential displacement.

7. The method for designing a liner with an equal life span for a semi-autogenous mill cylinder according to claim 1, characterized in that: exist In S10, the volume of the liner in the axial direction is redistributed, and the distribution formula is as follows; ； in, is the number of axial division areas, To redistribute the volume of each liner, is the total volume of the initial liner, C is the mass ratio of the redesigned liner to the initial liner, where Satisfy the following formula: ； in, For the region length, For the region Axial volume wear.

8. The method for designing a liner with an equal life span for a semi-autogenous mill cylinder according to claim 1, characterized in that: In S11, the liner volume in each radial area is distributed according to the following formula: ； in, is the number of radially divided regions, For the The volume of the axial region, After reallocation The first axial region The volume of the radial region, where Satisfy the following formula: ； in, For the The first axial region The wear volume of the radial area.

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