An eccentric stirred ball mill and related design method

Abstract

The application discloses an eccentric stirring type ball mill and a related design method, and relates to the technical field of ball mills, and solves the problem that both traditional ball mills and stirring mills have dead material zones. According to the application, the shaft axis of the stirring shaft is parallel to and does not coincide with the rotation axis of the cylinder body, and is arranged in the right lower quadrant or the left lower quadrant according to the rotation direction of the cylinder body. The position ensures that the blades accurately cover the dead material zone and avoid the medium falling area, ensures the active stirring effect and does not interfere with the normal falling track. The stirring blades are not arranged in a single straight line, but are arranged in a staggered mode along the stirring shaft. Adjacent groups of blades are staggered by a certain angle in the circumferential direction, so that the stirring resistance is dispersed, the stirring torque is concentrated, and the motor power fluctuation is reduced to the maximum extent, and the stability of the grinding process is ensured.

Description

Technical Field

[0001] This invention relates to the field of ball mill technology, specifically to an eccentric stirring ball mill and related design methods. Background Technology

[0002] Ball mills and stirred mills are the two most widely used fine grinding equipment in the powder processing field. Ball mills use a rotating cylinder to throw internal grinding media (such as steel balls) down, creating impact and grinding effects on the material. They are simple in structure and have a large processing capacity. Stirred mills, on the other hand, use a central stirring shaft to drive blades to rotate at high speed, directly agitating the grinding media and material, causing intense three-dimensional cyclic motion, thus generating powerful shearing, extrusion, and impact forces. However, both traditional ball mills and stirred mills face the common problem of high energy consumption during the grinding process, which has become a bottleneck restricting the industry's development.

[0003] A core reason for the high energy consumption of the aforementioned equipment lies in the existence of the "dead material zone." During ball mill operation, due to centrifugal force and friction, material adjacent to the liners is lifted and participates in the crushing process due to friction. However, in areas far from the liners, the material lacks sufficient friction and often remains relatively stationary or slides at low speed, forming the so-called "dead material zone" or "stationary layer." This portion of material cannot effectively participate in the grinding process, resulting in a large amount of electrical energy being consumed in driving ineffective material and media, rather than being used for actual crushing work. Although existing stirred mill technology alleviates this problem to some extent through forced stirring, traditional stirred mills typically have a stationary cylinder, lacking the advantage of the large drop impact of ball mills, and the central shaft stirring makes it difficult to reach the cylinder edges or specific dead corners. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an eccentric stirring ball mill and related design methods, which solves the problem of dead material zones in both traditional ball mills and stirred mills.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: an eccentric stirring ball mill, comprising a rotating cylinder, a main drive system, grinding media, a ball mill liner, and an eccentric independent drive stirring system; The rotary cylinder is placed horizontally and is driven by the main motor to rotate around the horizontal axis through a reducer and large and small gears. The inner wall of the cylinder is lined with corrugated or stepped lining plates. The rotary cylinder is filled with grinding media (steel balls, steel segments or ceramic balls). The media filling rate is set according to the fineness requirements of the material. The rotary cylinder is also equipped with partition plates to realize material classification and flow field control. The stirring shaft axis of the eccentrically driven stirring system is parallel to and eccentrically arranged with respect to the rotation axis of the rotary cylinder, and they do not coincide.

[0006] Preferably, the main drive system consists of a first main motor, a reducer, and large and small gear pairs, driving the cylinder to rotate continuously at a conventional ball mill speed.

[0007] Preferably, the eccentric independent drive stirring system adopts an independent dual-drive differential structure, equipped with a dedicated second drive motor. The stirring shaft speed is higher than the rotary drum speed, forming a speed difference to achieve forced stirring of materials. The stirring system is eccentrically arranged according to the rotation direction of the rotary drum: when the rotary drum rotates counterclockwise, the stirring shaft is eccentrically arranged in the lower right area of ​​the drum; when the rotary drum rotates clockwise, the stirring shaft is eccentrically arranged in the lower left area of ​​the drum. This eccentric position corresponds to the accumulating material in the drum, the low particle movement speed spill area, and the dead material area. The stirring blades are segmented and spirally staggered along the stirring shaft axis, with a set of blades set at a fixed distance along the axial direction. Adjacent sets of stirring blades are staggered by a fixed angle in the circumferential direction to evenly distribute the stirring torque. A safety gap is reserved between the end of the stirring blade and the liner.

[0008] Furthermore, a design method for an eccentrically stirred ball mill includes the following steps: Step 1: Build a 3D geometric model, input material and medium parameters, and select the contact and wear model; Step 2: Run the simulation until equilibrium is reached, determine the dead zone by particle velocity, and extract the core parameters of the dead zone; Step 3: Based on the premise that the blades completely cover the dead material area, set the range of values ​​for the stirring shaft position, blade length, and rotation speed ratio; Step 4: Establish the objective function focusing on three core aspects: grinding efficiency, unit energy consumption, and blade wear; Step 5: Obtain the Pareto optimal solution set through experimental design sampling, response surface fitting, and genetic algorithm solution.

[0009] Preferably, in step one, the input of material and medium parameters includes: Basic material parameters: density, Poisson's ratio, coefficient of restitution, coefficient of sliding friction, coefficient of rolling friction; Grinding media parameters: media material, size distribution, filling rate, and setting the media particle size distribution ratio.

[0010] Preferably, in step two, the specific method for extracting the core parameters of the dead material zone is as follows: The radial section of the cylinder is captured, and the velocity vector field data of all particles within the section are monitored and output. Set a dead zone determination threshold: if the average particle velocity in the area is lower than the set value and the duration exceeds the set time, the area is marked as a dead zone; The geometric center coordinates (x0, y0), volume range, and boundary contour data of the dead material zone are extracted using the post-processing function of the simulation software. The coordinates of the outer edge of the dead material zone are used as the reference point for the position of the end of the stirring blade.

[0011] Preferably, in step three, the specific method for setting the value range is as follows: Set the installation position of the stirring shaft (x, y): with the center of the mill as the center, offset to the lower right / lower left side along the rotation direction of the cylinder, with the initial offset distance being 0.15 times the effective radius R of the cylinder; Set the length L of the mixing blade: determine the minimum length Lmin and the maximum length Lmax to ensure that the blade tip covers the dead material zone and maintains a safe gap with the wall liner, satisfying Lmin≤L≤Lmax; Set the rotational speed ratio λ: λ is the ratio of the stirring shaft speed to the cylinder speed, with a constraint range of 1.2≤λ≤3. Here, the initial value is taken as 1.5. Integrate the parameters to form the design variable vector X=[x,y,L,λ], thus completing the initial design space definition of the mixing system.

[0012] Preferably, in step four, the specific method for establishing the objective function is as follows: Construct the grinding efficiency objective function η(X): Calculate the particle collision energy flux per unit time through simulation, and take maximizing the collision energy flux as the optimization objective; The objective function for unit energy consumption is constructed as follows: E(X) = (cylinder drive power Pshell + stirring system power Pstir) / grinding output Q, with minimizing unit energy consumption as the optimization objective; Construct the blade wear objective function W(X): calculate the blade wear volume per unit time based on the Archard model, and minimize the wear amount as the optimization objective; integrate multiple objective functions: minF(X)=[η(X),E(X),W(X)].

[0013] Preferably, in step five, the specific method for obtaining the Pareto optimal solution set is as follows: The Design of Experiments (DOE) method is used to generate uniformly distributed sample points within the design variable space; Substitute the sample points into the discrete element simulation to obtain the grinding efficiency, unit energy consumption, and blade wear data of the corresponding sample points. The response surface methodology (RSM) was used to fit an approximate mathematical relationship between the design variables and the three objective functions; Import the fitted model and use the NSGA-II genetic algorithm to solve the multi-objective optimization problem. After the calculation is completed, the Pareto optimal solution set is output.

[0014] This invention provides an eccentrically stirred ball mill and related design methods. Compared with the prior art, it has the following advantages: The ball mill cylinder and the internal stirring shaft rotate synchronously at different speeds, achieving a synergistic effect of impact crushing and shear grinding. The axis of the stirring shaft is parallel to but not coincident with the axis of rotation of the cylinder, and is arranged in the lower right or lower left quadrant depending on the direction of cylinder rotation. This position precisely covers the dead material zone, avoids the media drop zone, ensures active agitation effect, and does not interfere with the normal drop trajectory; The stirring blades are not arranged in a single straight line, but are staggered along the stirring axis; adjacent groups of blades are staggered at a certain angle in the circumferential direction to disperse the stirring resistance, avoid the concentration of stirring torque, thereby minimizing motor power fluctuations and ensuring the stability of the grinding process. Discrete element method (DEM) simulation was used to determine the location of the dead material zone, and a multi-objective optimization model incorporating grinding efficiency, energy consumption, and blade wear was constructed. A genetic algorithm was employed to solve for the Pareto optimal solution set, and the optimal combination of parameters for the stirring shaft position, blade length, and rotational speed ratio was determined based on different production requirements. The cylinder and stirring shaft use independent drive sources, with the stirring shaft rotating at a higher speed than the cylinder, forming a fixed speed ratio range. Differential motion increases the relative speed between the blades and the material, enhancing the shearing effect, while a torque limiting device prevents overload damage. Attached Figure Description

[0015] Figure 1 This is a schematic plan view of the eccentric stirring ball mill of the present invention; Figure 2 This is a cross-sectional schematic diagram of the eccentric stirring ball mill of the present invention; Figure 3 This is a schematic diagram of the simulation-based dead zone positioning method of the present invention; Figure 4 This is a simulation diagram of the stirring blade action based on multi-objective optimization according to the present invention; Reference numerals: 1. Rotary cylinder; 2. Ball mill liner; 3. Stirring blades; 4. Divider plate. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] First Embodiment Please see Figures 1 to 2 This application provides an eccentrically stirred ball mill, including a rotating cylinder 1, a main drive system, grinding media, a ball mill liner 2, and an eccentrically independently driven stirring system: The rotary cylinder 1 is placed horizontally and is driven by the main motor to rotate around the horizontal axis through the reducer and large and small gears. The inner wall of the cylinder is lined with corrugated or stepped lining plates to lift the grinding media and form a falling trajectory. The interior is filled with steel balls, steel segments or ceramic balls as grinding media. The media filling rate is set according to the fineness requirements of the material. The rotary cylinder 1 is also equipped with a partition plate 4 to realize material classification and flow field control. The main drive system consists of a first main motor, a reducer, and large and small gear pairs, which drive the cylinder to rotate continuously at the speed of a conventional ball mill, so as to realize the impact grinding of the grinding media. The eccentrically driven stirring system has an stirring shaft that is parallel to and eccentrically positioned with the cylinder's rotation axis, without overlap. When the cylinder rotates counterclockwise, the stirring shaft is positioned at the lower right of the cylinder; when the cylinder rotates clockwise, the stirring shaft is positioned at the lower left of the cylinder. This position precisely corresponds to the dead material zone / fall zone inside the cylinder, avoiding the impact zone of media falling and protecting the stirring components while forcibly activating the dead material. The stirring blades are segmented and spirally staggered along the stirring shaft axis; adjacent sets of blades are staggered at a fixed angle in the circumferential direction, so that the stirring resistance is evenly distributed along the axial direction, avoiding torque concentration and drastic fluctuations in motor power; the blade ends maintain a safe gap with the liner plate, so as not to interfere with the liner plate or partition plate; the stirring blades are not limited to the straight plate structure, but can also be replaced by spiral ribbon, arc-shaped spoon, perforated plate or flexible chain hammer. Unlike traditional stirred mills with a central axis arrangement, this stirring system employs an eccentric arrangement. Specifically, when the ball mill cylinder is set to rotate counterclockwise, the rotation axis of the eccentric stirring system is located at the lower right of the cylinder. According to the working mechanism of the ball mill, the upper left of the cylinder is the "drop zone" where the grinding media is lifted to its highest point by the liner and then thrown down. This area needs to be kept clear to ensure the impact force on the material in the lower left. The lower right of the cylinder is usually the "fall zone" or "dead material zone" where materials converge and move at a lower speed. Placing the stirring blades here avoids the high-intensity drop impact and accurately "digs out" and throws up the dead material deposited here, allowing it to re-enter the grinding cycle. If the cylinder rotates clockwise, the stirring system is correspondingly positioned at the lower left. The main drive system is started, and the cylinder rotates at a set speed. The liner drives the grinding media and materials to rise, and the media falls in the drop zone, forming a conventional ball mill effect of impact + grinding. Simultaneously, the eccentric stirring system is started, and the stirring shaft rotates at a speed higher than that of the cylinder. The eccentrically arranged staggered blades cut into the dead material zone in the lower right / lower left of the cylinder, forcibly digging up and throwing the stationary / low-speed materials to the drop zone in the upper part of the cylinder. The dead material is reintroduced into the grinding cycle, and the particle collision frequency is greatly increased, realizing ball mill impact + stirring shear synergistic grinding. The axially staggered blades evenly disperse resistance, reduce power fluctuations and equipment vibration, and ensure continuous and stable operation. After grinding, the material is discharged through the discharge device, realizing high-efficiency and low-energy fine grinding.

[0018] Second Embodiment Please see Figures 3 to 4 A design method for an eccentric stirring ball mill includes the following steps: Step 1: Build a 3D geometric model, input material and medium parameters, select the contact and wear model, and complete the pre-simulation settings: The 3D geometric model of the eccentrically stirred ball mill, including all components such as the cylinder, liners, stirring shaft, blades, and partition plates, was imported using EDEM or RockyDEM discrete element software. Basic material parameters were input: density, Poisson's ratio, coefficient of restitution, sliding friction coefficient, and rolling friction coefficient. Grinding media parameters were also input: media material, size distribution, and filling rate, with the media particle size distribution ratio set. The operating speed of the cylinder and the initial speed of the stirring shaft were set, and the equipment operating boundary conditions were determined. The nonlinear Hertz-Mindlin model was used to describe the normal and tangential contact forces between particles, and the Archard model was used to calculate the wear of the stirring blades. The simulation time step and total simulation duration were set to ensure that the simulation reached a dynamic equilibrium state. A three-dimensional geometric model of the target ball mill is established using discrete element method (DEM) software (such as EDEM or RockyDEM). Actual material parameters (density, Poisson's ratio, coefficient of restitution), grinding media gradation (steel ball size ratio), filling rate, and cylinder rotation speed are input. Simulation continues until the system reaches dynamic equilibrium. The velocity vector field of particles within the cylinder cross-section is monitored. When the average velocity in a region is below a certain value and the duration exceeds a certain value, it is determined to be a dead zone. The geometric center coordinates and volume range of the dead zone are extracted and used as the reference point for the installation position of the eccentric stirring shaft. In discrete element simulation, the motion of each particle is described by Newton's equations of motion:

[0019]

[0020] In the formula, m i Let i be the mass of particle i; The translational velocity of the particle; and These represent the normal contact force and the tangential contact force between particle i and particle j, respectively. I represents the force exerted by the gas on particle i. i Let be the moment of inertia of the particle. ω is the angular velocity of the particle; The vector pointing from the particle center to the contact point. μ r Let be the rolling friction coefficient affected by particle i. The interaction between particles is calculated using a nonlinear Hertz model:

[0021]

[0022]

[0023]

[0024] in, For equivalent Young's modulus, For the equivalent radius, The normal overlap is... For equivalent quality, Here, e represents the relative normal velocity, and e is the coefficient of restitution. For equivalent shear modulus, This is the tangential overlap. For relative tangential velocity, μ s The coefficient of sliding friction; Wear was calculated using the Archard model:

[0025] In the formula, The wear volume of the geometry within one simulation time step; J is the work done by the contact force between the particle and the surface of the geometry within one time step; This is an empirical constant for wear; the smaller the value, the more wear-resistant the geometric material. This represents the tangential component of the contact force between the particle and the surface of the geometric body. The relative displacement of the particle in the tangential plane within one time step; Step 2: Run the simulation until equilibrium is reached. Determine the dead zone based on particle velocity and extract the core parameters of the dead zone. Initiate discrete element simulation and run continuously until the particle motion inside the cylinder reaches dynamic equilibrium. Capture a radial section of the cylinder, monitor and output the velocity vector field data of all particles within the section; set a dead zone threshold: if the average particle velocity within the zone is lower than a set value and the duration exceeds a set time, the zone is marked as a dead zone; use the simulation software's post-processing function to extract the geometric center coordinates (x0, y0), volume range, and boundary contour data of the dead zone; use the dead zone edge coordinates as the reference point for the end position of the stirring blades to determine the positioning basis of the stirring system. Based on the location of the dead material zone, the initial design space of the stirring system is determined. Installation position (x, y): Offset to the lower right by a certain value from the mill center (when the ball mill cylinder is set to rotate counterclockwise, the rotation axis of the eccentric stirring system is located at the lower right of the cylinder; if the cylinder rotates clockwise, the stirring system is correspondingly arranged at the lower left, with the value between 0.1R and 0.4R). Blade length L: The blade tip position is centered on the edge of the dead material zone, maintaining sufficient clearance from the wall liner, i.e. Rotational speed ratio λ: defined as the ratio of the rotational speed of the stirring blades to the rotational speed of the cylinder, set between 1.2 and 3; Step 3: Using the dead material zone as a reference, set the range of values ​​for the stirring shaft position, blade length, and speed ratio: Set the installation position of the stirring shaft (x, y): With the mill center as the center, offset it to the lower right / lower left side along the rotation direction of the cylinder. The offset distance is 0.1~0.4 times the effective radius R of the cylinder, preferably 0.15 times. Set the length L of the stirring blades: Determine the minimum length Lmin and the maximum length Lmax to ensure that the blade tips cover the dead material zone and maintain a safe clearance with the wall liner, satisfying Lmin≤L≤Lmax. Set the speed ratio λ: λ is the ratio of the stirring shaft speed to the cylinder speed, with a constraint range of 1.2≤λ≤3. Integrate the parameters to form the design variable vector X=[x,y,L,λ], completing the initial design space definition of the stirring system; Objective function vector: ,in Design a variable vector. The objective is to maximize grinding efficiency. Characterized by simulating the collision energy flux of particles per unit time. Minimizing unit energy consumption. in, For cylinder drive power, For the power of the stirring system, The simulation predicts the grinding output. Minimize blade wear W(X): Based on the Archard wear model, calculate the wear amount per unit time on the surface of the stirring blade; Step 4: Establish the objective function focusing on three core aspects: grinding efficiency, unit energy consumption, and blade wear. The grinding efficiency objective function η(X) is constructed by simulating and statistically analyzing the particle collision energy flux per unit time, with maximizing the collision energy flux as the optimization objective. The unit energy consumption objective function E(X) is constructed: E(X) = (cylinder drive power Pshell + stirring system power Pstir) / grinding output Q, with minimizing unit energy consumption as the optimization objective. The blade wear objective function W(X) is constructed by calculating the blade wear volume per unit time based on the Archard model, with minimizing the wear amount as the optimization objective. Multiple objective functions are integrated: minF(X) = [η(X), E(X), W(X)], to complete the optimization model construction. The above model was solved using the response surface methodology (RSM) combined with a genetic algorithm (NSGA-II). Sample points were obtained through design of experiments (DOE), an approximate relationship between the objective function and variables was fitted, and the Pareto optimal solution set was found using the genetic algorithm. Step 5: Obtain the Pareto optimal solution set through experimental design sampling, response surface fitting, and genetic algorithm solution. The Design of Experiments (DOE) method was used to generate uniformly distributed sample points within the design variable space. These sample points were then substituted into a Discrete Element Method (DEM) simulation to obtain data on grinding efficiency, unit energy consumption, and blade wear for each sample point. The Response Surface Method (RSM) was used to fit an approximate mathematical relationship between the design variables and the three objective functions. The fitted model was then imported, and the NSGAII genetic algorithm was used for multi-objective optimization. After the calculations were completed, the Pareto optimal solution set was output, containing all optimal parameter combinations that considered efficiency, energy consumption, and wear. Based on actual production needs and preferences (such as "energy saving priority" or "output priority"), the optimal combination of design parameters is selected from the Pareto optimal solution set. Finally, the optimized parameters are substituted into the discrete element model for verification simulation to confirm the dead zone elimination effect and energy efficiency improvement ratio. Finally, manufacturing drawings are output, completing the customized equipment design.

[0026] Some of the data in the above formulas are numerical calculations with dimensions removed, and the contents not described in detail in this specification are all prior art known to those skilled in the art.

[0027] The above embodiments are only used to illustrate the technical methods of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical methods of the present invention without departing from the spirit and scope of the technical methods of the present invention.

Claims

1. An eccentric stirring ball mill, characterized in that, It includes the rotary drum, main drive system, grinding media, ball mill liners, and eccentric independent drive stirring system; The rotary cylinder is placed horizontally and is driven by the main motor to rotate around the horizontal axis through a reducer and large and small gears. The inner wall of the cylinder is lined with corrugated or stepped lining plates. The rotary cylinder is filled with grinding media, and the media filling rate is set according to the fineness requirements of the material. The rotary cylinder is also equipped with partition plates to realize material classification and flow field control. The stirring shaft axis of the eccentrically driven stirring system is parallel to and eccentrically arranged with respect to the rotation axis of the rotary cylinder, and they do not coincide.

2. The eccentric stirring ball mill according to claim 1, characterized in that, The main drive system consists of a first main motor, a reducer, and large and small gear pairs, which drive the cylinder to rotate continuously at a conventional ball mill speed.

3. The eccentric stirring ball mill according to claim 1, characterized in that, The eccentric independent drive stirring system adopts an independent dual drive differential speed structure and is equipped with a dedicated second drive motor. The stirring shaft speed is higher than the rotary drum speed, forming a speed difference to achieve forced stirring of materials. The stirring system is eccentrically arranged according to the rotation direction of the rotary drum: when the rotary drum rotates counterclockwise, the stirring shaft is eccentrically arranged in the lower right area of ​​the drum; when the rotary drum rotates clockwise, the stirring shaft is eccentrically arranged in the lower left area of ​​the drum; this eccentric position corresponds to the cascading area where materials accumulate in the drum, the low particle movement speed, and the dead material area; The stirring blades are segmented and spirally staggered along the stirring shaft axis. A set of blades is set at a fixed distance along the axial direction, and adjacent sets of stirring blades are staggered at a fixed angle in the circumferential direction to evenly distribute the stirring torque. A safety gap is reserved between the end of the stirring blade and the liner.

4. A design method for an eccentrically stirred ball mill, wherein the method is used to design an eccentrically stirred ball mill as described in any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Build a 3D geometric model, input material and medium parameters, and select the contact and wear model; Step 2: Run the simulation until equilibrium is reached, determine the dead zone by particle velocity, and extract the core parameters of the dead zone; Step 3: Based on the premise that the blades completely cover the dead material area, set the range of values ​​for the stirring shaft position, blade length, and rotation speed ratio; Step 4: Establish the objective function focusing on three core aspects: grinding efficiency, unit energy consumption, and blade wear; Step 5: Obtain the Pareto optimal solution set through experimental design sampling, response surface fitting, and genetic algorithm solution.

5. The design method of an eccentric stirring ball mill according to claim 4, characterized in that, In step one, the input of material and medium parameters includes: Basic material parameters: density, Poisson's ratio, coefficient of restitution, coefficient of sliding friction, coefficient of rolling friction; Grinding media parameters: media material, size distribution, filling rate, and setting the media particle size distribution ratio.

6. The design method of an eccentric stirring ball mill according to claim 4, characterized in that, In step two, the specific method for extracting the core parameters of the dead material zone is as follows: The radial section of the cylinder is captured, and the velocity vector field data of all particles within the section are monitored and output. Set a dead zone determination threshold: if the average particle velocity in the area is lower than the set value and the duration exceeds the set time, the area is marked as a dead zone; The geometric center coordinates (x0, y0), volume range, and boundary contour data of the dead material zone are extracted using the post-processing function of the simulation software. The coordinates of the outer edge of the dead material zone are used as the reference point for the position of the end of the stirring blade.

7. The design method of an eccentric stirring ball mill according to claim 4, characterized in that, In step three, the specific method for setting the value range is as follows: Set the installation position of the stirring shaft (x, y): with the center of the mill as the center, offset to the lower right / lower left side along the rotation direction of the cylinder, with the initial offset distance being 0.15 times the effective radius R of the cylinder; Set the length L of the mixing blade: determine the minimum length Lmin and the maximum length Lmax to ensure that the blade tip covers the dead material zone and maintains a safe gap with the wall liner, satisfying Lmin≤L≤Lmax; Set the rotational speed ratio λ: λ is the ratio of the stirring shaft speed to the cylinder speed, with a constraint range of 1.2≤λ≤3. Here, the initial value is taken as 1.

5. Integrate the parameters to form the design variable vector X=[x,y,L,λ], thus completing the initial design space definition of the mixing system.

8. The design method of an eccentric stirring ball mill according to claim 4, characterized in that, In step four, the specific method for establishing the objective function is as follows: Construct the grinding efficiency objective function η(X): Calculate the particle collision energy flux per unit time through simulation, and take maximizing the collision energy flux as the optimization objective; The objective function for unit energy consumption is constructed as follows: E(X) = (cylinder drive power Pshell + stirring system power Pstir) / grinding output Q, with minimizing unit energy consumption as the optimization objective; Construct the blade wear objective function W(X): calculate the blade wear volume per unit time based on the Archard model, and minimize the wear amount as the optimization objective; integrate multiple objective functions: minF(X)=[η(X),E(X),W(X)].

9. The design method of an eccentric stirring ball mill according to claim 4, characterized in that, In step five, the specific method for obtaining the Pareto optimal solution set is as follows: The Design of Experiments (DOE) method is used to generate uniformly distributed sample points within the design variable space; Substitute the sample points into the discrete element simulation to obtain the grinding efficiency, unit energy consumption, and blade wear data of the corresponding sample points. The response surface methodology (RSM) was used to fit an approximate mathematical relationship between the design variables and the three objective functions; Import the fitted model and use the NSGA-II genetic algorithm to solve the multi-objective optimization problem. After the calculation is completed, the Pareto optimal solution set is output.

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