Method and device for optimizing the ratio of the inner and outer diameter of a multi-size hematite separation spiral chute

Abstract

The application discloses a multi-particle-size hematite separation spiral chute inner-to-outer diameter ratio optimization method and equipment, relates to the technical field of mineral processing and gravity separation, and comprises the following steps: constructing a three-dimensional parameterized geometric model comprising a spiral chute inner-to-outer diameter ratio, constructing a spiral chute three-dimensional geometric model comprising a plurality of different spiral chute inner-to-outer diameter ratios, performing discretization processing on the spiral chute three-dimensional geometric model to obtain a calculation domain grid, and obtaining material characteristic parameters and separation operation parameters of target hematite slurry. Through flow field and particle simulation, the application can reduce the deviation between the model and the actual slurry system. By constructing a comprehensive evaluation index to determine the optimal inner-to-outer diameter ratio, the optimal inner-to-outer diameter ratio suitable for different particle sizes of materials can be determined, the matching degree of the structural parameters and the hematite separation working condition is effectively improved, and the adaptation deviation caused by pure dependence on single flow field data optimization is reduced.

Description

Technical Field

[0001] This invention relates to the field of mineral processing and gravity beneficiation technology, and in particular to a method and equipment for optimizing the inner and outer diameter ratio of a spiral chute for multi-size hematite beneficiation. Background Technology

[0002] Gravity separation is the mainstream low-energy process for separating hematite. Spiral sluices are widely used in the separation of various minerals due to their simple structure, large throughput, and low operation and maintenance costs. The particle size distribution of the raw hematite ore used in production varies significantly. The stratification and migration state of particles within the thin film of the slurry directly determine the concentrate grade, iron recovery rate, and separation efficiency. Therefore, the industry urgently needs a quantitative optimization design scheme for spiral sluices that can adapt to hematite ore materials with multiple particle sizes.

[0003] Current structural optimization of spiral chutes mostly focuses on parameters such as equipment diameter, pitch, cross-sectional shape, and downward slope. Some technologies improve sorting efficiency through auxiliary means such as adding grooves to the chute surface or applying external magnetic fields. During optimization and industrial scale-up, the ratio of the spiral chute's inner and outer diameters is generally set to a fixed value, rather than being optimized as an independent control parameter. Equipment finalization relies on on-site trial and error and empirical judgment, and numerical simulations only use traditional multiphase flow models to calculate the flow field.

[0004] Currently, when optimizing spiral chutes, the multiphase flow model does not consider the Begno forces induced by particle collision shear in the thin film of slurry, making it difficult to accurately characterize the stratification and migration patterns of particles of different sizes. In addition, the method of judging the sorting effect based on a single index and manual weighting is highly subjective, and the obtained structural optimization parameters are difficult to adapt to hematite materials with large particle size fluctuations. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and equipment for optimizing the inner and outer diameter ratio of multi-grain size hematite spiral chute, which solves the problems of model distortion and poor adaptability in the optimization of iron ore spiral chute in existing technologies.

[0006] The technical means employed in this invention are as follows: In a first aspect, the present invention provides a method for optimizing the inner and outer diameter ratio of a spiral chute for sorting multi-size hematite, comprising: A three-dimensional parametric geometric model including the inner and outer diameter ratio of the spiral chute is constructed. A three-dimensional geometric model of the spiral chute including multiple spiral chutes with different inner and outer diameter ratios is constructed. The three-dimensional geometric model of the spiral chute is discretized to obtain a computational domain mesh. Obtain the material characteristic parameters and sorting operation parameters of the target hematite slurry. Based on the material characteristic parameters and the sorting operation parameters, construct a hematite-quartz slurry system including different particle size combinations, and a gas-liquid-solid multiphase flow numerical calculation model corresponding to the three-dimensional parameterized geometric model. The gas-liquid-solid multiphase flow numerical calculation model includes the Baigno power source term. Based on the computational domain grid and the gas-liquid-solid multiphase flow numerical calculation model, numerical simulations were performed on the clear water flow field and the multiphase flow field of hematite slurry under different spiral chute inner-outer diameter ratios to obtain the flow field dynamic parameters and particle motion distribution parameters under different spiral chute inner-outer diameter ratios. The spiral chute surface under different spiral chute inner-outer diameter ratios is divided into multiple target regions radially. Within each target region, multiple radial micro-regions are further divided. The outer boundary of each radial micro-region is used as the simulated cutter position. Based on the hematite-quartz slurry system, the flow field dynamics parameters, and the particle motion distribution parameters, the sorting performance index is calculated for different spiral chute inner-outer diameter ratios and different combinations of simulated cutter positions. Based on the sorting performance indicators, an original decision matrix is ​​constructed. The original decision matrix is ​​then dimensionless to obtain a normalized decision matrix. The objective weights of the sorting performance indicators are determined. The normalized decision matrix and the objective weights are coupled to obtain a comprehensive performance evaluation index. The ratio of the inner and outer diameters of the spiral chute to that of different hematite materials is determined based on the comprehensive performance evaluation index.

[0007] Furthermore, the formula for calculating the ratio of the inner and outer diameters of the spiral chute is as follows: , in, Indicates the ratio of the inner and outer diameters of the spiral chute. Indicates the inner radius of the spiral chute. This indicates the outer radius of the spiral chute; the ratio of the inner to outer diameter of the spiral chute ranges from 0.100 to 0.475.

[0008] Furthermore, the structural parameters of the three-dimensional parametric geometric model include at least one of the following: outer radius, pitch, downsloping angle, parabolic exponent of the cross section, total number of turns, and inner-outer diameter ratio; The material characteristic parameters include at least one of the following: number of particle types, particle size, particle density, particle volume ratio, slurry solids concentration, and feed iron grade. The sorting operation parameters include at least one of the following: inlet flow rate, inlet velocity, and inlet / outlet hydraulic diameter.

[0009] Furthermore, the formula for calculating the inlet velocity is: , in, Indicates the inlet velocity. S represents the inlet flow rate, and S represents the inlet area. The formula for calculating the hydraulic diameter of the inlet and outlet is: , in, C represents the hydraulic diameter of the inlet and outlet, and C represents the circumference of the inlet and outlet.

[0010] Furthermore, the numerical calculation model for gas-liquid-solid multiphase flow includes the VOF free surface model, the Eulerian Multi Fluid VOF multiphase flow model, and the RNG k-ε turbulence model; In the Eulerian Multi Fluid VOF multiphase flow model, a Begnostic source term is introduced as a source term, which is determined based on the Begnostic number; The formula for calculating the Baigno number is as follows: , in, Represents the Baigno number, Indicates the linear concentration of particles. d represents particle density. s Indicates particle diameter, Indicates the viscosity of the liquid phase. Indicates the average velocity shear rate; The formula for calculating the linear concentration of the particles is: , in, This represents the maximum volume fraction of particles when statically packed. This indicates the volume concentration of particles.

[0011] Furthermore, the flow field dynamic parameters include at least one of the following: film thickness, mainstream tangential velocity, secondary circulation radial velocity, and turbulent kinetic energy; The particle motion distribution parameters include at least one of the following: cumulative radial flux of particles, particle enrichment rate, and radial distribution characteristics of particles. The formula for calculating the thickness of the flow film is: , in, Indicates film thickness. Indicates the height of the gas-liquid interface. Indicates the height of the bottom wall of the tank; The formula for calculating the particle enrichment rate is as follows: , in, Indicates particle enrichment rate. This represents the volume fraction of particles with a certain property in a local mesh. This indicates the volume fraction of particles in the feed.

[0012] Furthermore, the multiple target regions include an inner edge region, a middle region, and an outer edge region; The expression for the radial range of the inner edge region is: , The expression for the radial range of the intermediate region is: , The expression for the radial range of the outer edge region is: , in, Indicates the radial position of the groove surface. Indicates the inner radius of the spiral chute. This indicates the outer radius of the spiral chute.

[0013] Furthermore, the separation performance indicators include at least one of concentrate yield, concentrate iron grade, iron recovery rate, and separation efficiency; The expression for the original decision matrix is: , in, Represents the original decision matrix. Indicates the ratio of inner to outer diameter is The concentrate yield value at that time, Indicates the ratio of inner to outer diameter is At that time, the iron grade of the concentrate Indicates the ratio of inner to outer diameter is Iron recovery rate at that time Indicates the ratio of inner to outer diameter is Separation efficiency at that time.

[0014] Furthermore, the expression for the elements in the normalized decision matrix is: , in, This represents the j-th element in the i-th design scheme. This represents the original value of the j-th indicator in the i-th design scheme. and Let represent the minimum and maximum values ​​of the j-th sorting performance index among all design schemes, respectively; The formula for calculating the objective weight is: , in, This represents the objective weight of the j-th evaluation indicator. This represents the coefficient of variation for the j-th indicator. Indicates the number of sorting indicators; The formula for calculating the comprehensive performance evaluation index is as follows: , in, Let be the comprehensive performance evaluation index of the i-th design scheme.

[0015] Secondly, the present invention also provides a multi-size hematite sorting device, including a spiral chute and a cutter; The spiral chute has an inner radius and an outer radius, and the ratio of the inner radius to the outer radius is the inner-outer diameter ratio determined by the inner-outer diameter ratio optimization method for multi-grain size hematite sorting spiral chute as described in any one of the first aspects. The two ends of the spiral chute are the feed port and the discharge port, respectively. The cutter is set on the chute surface near the discharge port. The cutter is set radially along the chute surface at the outer boundary of the radial micro-region determined by the optimization method.

[0016] Compared with the prior art, the present invention has the following advantages: This invention constructs a gas-liquid-solid multiphase flow numerical calculation model including the Baigno power source term, and combines multiple sets of three-dimensional parametric geometric models for flow field and particle simulation, which can reduce the deviation between the model and the actual slurry system. By combining radial partition micro-area interception measurement and sorting index with objective weights to obtain a comprehensive evaluation index, it can take into account the working conditions of hematite-quartz slurry with different particle sizes, determine the optimal inner and outer diameter ratio of the suitable material, effectively improve the matching degree between structural parameters and hematite sorting conditions, and reduce the adaptation deviation caused by simply relying on a single flow field data for optimization.

[0017] Based on the above reasons, this invention can be widely applied in fields such as mineral processing and gravity beneficiation. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the process for optimizing the inner and outer diameter ratio of a spiral chute for sorting multi-size hematite in an embodiment of the present invention. Figure 2These are schematic diagrams showing the cross-sectional shapes of spiral chutes with different inner and outer diameter ratios in embodiments of the present invention; Figure 3 The geometric models and computational domain meshes of spiral chutes with different inner and outer diameter ratios are shown in the embodiments of the present invention; wherein, (a) computational domain meshes of spiral chutes with different inner and outer diameter ratios, (b) cross-sectional meshes of spiral chutes with inner and outer diameter ratio W=0.175, and (c) meshes of the first ring of spiral chutes with inner and outer diameter ratio W=0.175. Figure 4 This is a diagram showing the distribution of turbulent kinetic energy in the first rotation of spiral chutes with different inner and outer diameter ratios in an embodiment of the present invention. Figure 5 The enrichment ratio distribution of spiral chutes with different inner and outer diameter ratios in slurry system A is shown in the embodiment of the present invention; where (a) is 90 μm hematite and (b) is 38 μm quartz. Figure 6 The enrichment ratio distribution of spiral chutes with different inner and outer diameter ratios in slurry system B is shown in the embodiment of the present invention; where (a) is 59 μm hematite and (b) is 38 μm quartz. Figure 7 The enrichment ratio distribution of spiral chutes with different inner and outer diameter ratios in slurry system C is shown in the embodiment of the present invention; where (a) is 38μm hematite and (b) is 38μm quartz. Figure 8 This is a radial distribution diagram of concentrate yield of spiral chute with different inner and outer diameter ratios as a function of cutter position in an embodiment of the present invention; wherein, (a) slurry system A, (b) slurry system B, and (c) slurry system C; Figure 9 This is a radial distribution diagram of the iron grade of the concentrate in spiral sluices with different inner and outer diameter ratios as a function of the cutter position in an embodiment of the present invention; wherein, (a) slurry system A, (b) slurry system B, and (c) slurry system C; Figure 10 This is a radial distribution diagram of the iron recovery rate of spiral chute with different inner and outer diameter ratios as a function of the cutter position in an embodiment of the present invention; wherein, (a) slurry system A, (b) slurry system B, and (c) slurry system C; Figure 11 This is a radial distribution diagram of the separation efficiency of spiral chute with different inner and outer diameter ratios as a function of the cutter position in an embodiment of the present invention; wherein, (a) slurry system A, (b) slurry system B, and (c) slurry system C; Figure 12 This is a graph showing the relationship between the comprehensive performance evaluation index and the inner / outer diameter ratio under different slurry systems in this invention embodiment; Figure 13 The following are schematic diagrams of the spiral chute with optimized inner and outer diameter ratio in an embodiment of the present invention: (a) Schematic diagram of spiral chute with W=0.325, (b) Schematic diagram of spiral chute with W=0.400, (c) Top view of spiral chute.

[0020] In the diagram: 1. Spiral chute; 11. Inner edge area; 12. Middle area; 13. Outer edge area; 2. Feed port; 3. Chute surface; 4. Cutting device; 5. Discharge port. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "comprising" and "having" and any variations thereof in this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0023] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0024] Please see Figure 1 This application provides a method for optimizing the inner and outer diameter ratio of a spiral chute for sorting multi-size hematite, including the following steps: Step 101: Construct a three-dimensional parametric geometric model including the inner and outer diameter ratio of the spiral chute. Construct a three-dimensional geometric model of the spiral chute including multiple spiral chute inner and outer diameter ratios. Discretize the three-dimensional geometric model of the spiral chute to obtain the computational domain mesh.

[0025] Construct a three-dimensional parametric geometric model with the ratio of the inner and outer diameters (W) of the spiral chute as the core variable. The structural parameters of the three-dimensional parametric geometric model may include the outer radius. Pitch P, Down bevel angle The system comprises at least one of the following: the parabolic exponent n, the total number of turns T, and the inner-outer diameter ratio W. For example, the outer radius can be 200 mm, the pitch can be 240 mm, the downsloping angle can be 12°, the parabolic exponent n can be 3, the total number of turns can be 3.25, and the inner-outer diameter ratio of the spiral chute can range from 0.100 to 0.475. By constructing a three-dimensional parametric geometric model with multiple parameters, a data foundation can be provided for the subsequent construction of a numerical calculation model for gas-liquid-solid multiphase flow.

[0026] In some implementations, the formula for calculating the ratio of the inner and outer diameters of the spiral chute is: , in, Indicates the ratio of the inner and outer diameters of the spiral chute. Indicates the inner radius of the spiral chute. This indicates the outer radius of the spiral chute.

[0027] When the outer radius is fixed At that time, the inner radius of the spiral chute Set them to R respectively i1 R i2 , ..., R ix That is, the ratios of the inner and outer radii are W1, W2, ..., W respectively. k A total of k different inner and outer diameter ratios are set. For an example, please refer to... Figure 2 and Figure 3 The inner radius can be set to 20, 35, 50, 65, 80 and 95 mm respectively. When the outer radius is set to 200 mm, the inner and outer diameter ratios are 0.100, 0.175, 0.250, 0.325, 0.400 and 0.475 respectively, for a total of 6 different inner and outer diameter ratios.

[0028] A three-dimensional geometric model of a spiral chute with multiple different inner and outer diameter ratios was constructed. The three-dimensional geometric model of the spiral chute was discretized to obtain a computational domain mesh. By dividing the three-dimensional geometric model of the spiral chute with different inner and outer diameter ratios into differentiated computational domain meshes, the curvature and cross-sectional size characteristics of each chute channel were accurately matched to eliminate numerical calculation errors caused by uneven mesh size and improve the reliability of the comparison of flow field and particle motion simulation results under multiple geometric structures.

[0029] Step 102: Obtain the material characteristic parameters and sorting operation parameters of the target hematite slurry. Based on the material characteristic parameters and sorting operation parameters, construct a hematite-quartz slurry system with different particle size combinations, as well as a gas-liquid-solid multiphase flow numerical calculation model corresponding to the three-dimensional parameterized geometric model. The gas-liquid-solid multiphase flow numerical calculation model includes the Baigno power source term.

[0030] This invention breaks through the limitations of existing technologies that only focus on the basic structure of the channel surface or the optimization of the cross-sectional curve, and takes the inner-outer diameter ratio as an independently adjustable core geometric parameter; by introducing the Baigno force source term into the numerical model, it can more realistically reflect the particle collision, dispersion pressure and vertical stratification effect in the thin flow film with different particle size composition systems, thereby improving the simulation accuracy of the migration law of coarse and fine particles.

[0031] Specifically, based on the actual material properties and operating conditions, the material characteristic parameters and sorting operation parameters of the hematite slurry to be sorted are obtained. In this way, a numerical calculation model of the hematite-quartz slurry system and the gas-liquid-solid multiphase flow is constructed. The complete configuration of the corresponding numerical calculation model, boundary conditions and solution settings is completed. The Begno force source term is used to characterize the influence of particle collision and dispersion pressure in the thin film shear motion of the slurry on the vertical stratification, radial migration and enrichment behavior of hematite particles and quartz particles of different sizes.

[0032] The boundary conditions can include inlet boundary, outlet boundary, and wall boundary; the inlet boundary can be set as inlet velocity; the outlet boundary can be set as outlet pressure, which can be standard atmospheric pressure; the wall boundary corresponding to the lower wall of the spiral chute can be set as a no-slip wall, the near-wall region can be designed using standard wall functions, and the wall boundary corresponding to the upper wall of the chute can be set as a free-slip wall. The solution settings can include the basic solver type, spatial discretization scheme, and convergence control. The basic solver type can be a pressure-based solver. The finite volume method is used for discretizing the governing equations. Pressure-velocity coupling can use the Phase Coupled SIMPLE algorithm, and gradient discretization can use LeastSquares Cell-Based. The pressure interpolation scheme can use PRESTO!. The momentum equation, turbulent kinetic energy equation, and turbulent dissipation rate equation can be discretized using a second-order upwind scheme. The convergence criterion can be set to a residual of less than 10. -4 .

[0033] For example, hematite particles with diameters of 90μm, 59μm, and 38μm were combined with quartz gangue mineral particles with a uniform diameter of 38μm to obtain three types of hematite-quartz slurry systems. The material parameters corresponding to each system are shown in Table 1.

[0034] Table 1. Material parameters of three representative hematite-quartz slurry systems

[0035] In some embodiments, the material characteristic parameters include at least one of the following: number of particle types, particle size, particle density, particle volume ratio, slurry solids concentration, and feed iron grade; the separation operation parameters include at least one of the following: inlet flow rate, inlet velocity, and inlet / outlet hydraulic diameter. By selecting the corresponding material characteristic parameters and separation operation parameters, the input conditions of the hematite-quartz slurry system and the gas-liquid-solid multiphase flow numerical calculation model are matched, facilitating the reproduction of the actual working characteristics of particle flow and separation within the slurry.

[0036] In some implementations, the formula for calculating the inlet velocity is: , in, Indicates the inlet velocity. S represents the inlet flow rate, and S represents the inlet area. The formula for calculating the hydraulic diameter of the inlet and outlet is: , in, C represents the hydraulic diameter of the inlet and outlet, and C represents the circumference of the inlet and outlet.

[0037] For example, inbound traffic It can be 12L / min, inlet velocity The speed can be 0.1177 m / s, and the inlet and outlet hydraulic diameters are... The diameter can be 0.0265m, and the entrance area S can be 0.0017m². 2 The perimeter C of the entrance / exit can be 0.2564m.

[0038] In some implementations, the numerical calculation model for gas-liquid-solid multiphase flow includes the VOF free surface model, the Eulerian Multi Fluid VOF multiphase flow model, and the RNG k-ε turbulence model; wherein, the VOF free surface model is used for simulating the flow field of clear water, the Eulerian Multi Fluid VOF multiphase flow model is used for simulating the flow field of slurry, and the RNG k-ε turbulence model is used for simulating the complex turbulence of a spiral chute.

[0039] Numerical simulations of the clear water flow field in a spiral chute were conducted using the RNG k-ε turbulence model and the VOF free surface model under different in-to-outer diameter ratios to obtain the machine evolution characteristics of a stable gas-liquid two-phase flow field. By introducing a particle phase into the stable gas-liquid two-phase flow field, the Eulerian Multi Fluid VOF multiphase flow model, which includes a Begno force source term, was coupled into the momentum equation using the RNG k-ε turbulence model. Numerical simulations of the slurry flow field in the spiral chute under different in-to-outer diameter ratios were then performed to obtain the gas-liquid-solid multiphase flow field characteristics and particle motion information.

[0040] In the Eulerian Multi Fluid VOF multiphase flow model, a Begnault force source term is introduced as a source term. This Begnault force source term is determined based on the Begnault number. By introducing the Begnault force source term, calculated based on the Begnault number, into the Eulerian Multi Fluid VOF multiphase flow model as a source term in the governing equations, the interaction forces between solid particles and fluid under different flow regimes are adapted, thereby improving the accuracy of the multiphase flow model in characterizing particle flow behavior.

[0041] The Begnostic force source term is determined segmentally based on the particle inertial region, transition region, or macroscopic viscous region where the Begnostic number is located. The expression for the Begnostic force source term is:

[0042] in, Let N represent the Beginner force source term, and N represent the Beginner number. d represents particle density. s Indicates particle diameter, Indicates the viscosity of the liquid phase. Indicates the average velocity shear rate. This indicates a linear concentration.

[0043] The formula for calculating the Beginno number is: , in, Represents the Baigno number, Indicates the linear concentration of particles. d represents particle density. s Indicates particle diameter, Indicates the viscosity of the liquid phase. Indicates the average velocity shear rate; The formula for calculating the linear concentration of particles is: , in, This represents the maximum volume fraction of particles when statically packed. This indicates the volume concentration of particles.

[0044] Step 103: Based on the computational domain grid and the gas-liquid-solid multiphase flow numerical calculation model, numerical simulations were performed on the clear water flow field and the hematite slurry multiphase flow field under different spiral sluice inner-outer diameter ratios. The flow field dynamic parameters and particle motion distribution parameters under different spiral sluice inner-outer diameter ratios were obtained. This reflects the differentiated trends of different inner-outer diameter ratios acting on the clear water flow field and the hematite slurry multiphase flow field of the spiral sluice, facilitating the distinction between the motion and aggregation characteristics of hematite particles and the fluid dynamic changes within the sluice under different spiral sluice inner-outer diameter ratios.

[0045] In some implementations, the flow field dynamics parameters include at least one of film thickness, mainstream tangential velocity, secondary circulation radial velocity, and turbulent kinetic energy; the particle motion distribution parameters include at least one of cumulative radial flux, particle enrichment rate, and particle radial distribution characteristics. By selecting flow field dynamics parameters such as film thickness and mainstream tangential velocity, as well as particle motion distribution parameters such as cumulative radial flux and particle enrichment rate, the differences in motion between the fluid and hematite particles inside the spiral chute under different inner-outer diameter ratios can be reflected from two dimensions: fluid flow and particle migration.

[0046] The formula for calculating the thickness of the flow film is: , in, Indicates film thickness. Indicates the height of the gas-liquid interface. This indicates the height of the bottom wall of the tank.

[0047] The formula for calculating particle enrichment rate is: , in, Indicates particle enrichment rate. This represents the volume fraction of particles with a certain property in a local mesh. This indicates the volume fraction of particles in the feed.

[0048] The distribution pattern of the radial velocity of the secondary circulation along the relative water depth is obtained. The formula for calculating the relative water depth is:

[0049] in, Indicates relative water depth. Indicates any water depth position. This indicates the thickness of the flow film.

[0050] Please see Figure 4 Increasing the inner-outer diameter ratio expands the turbulent kinetic energy and its distribution range, which is beneficial for promoting the sedimentation and stratification of high-density particles and shortening the time and journey of hematite enrichment towards the inner edge. However, strong turbulence can cause slurry mixing, interfering with hematite sedimentation, inhibiting its inward enrichment, and causing it to be mixed in the middle region or even lost in the outer tailings region. Therefore, the inner-outer diameter ratio, through geometric constraints, changes the intensity of turbulent kinetic energy and the location of its high-value areas radially and along the path, thereby altering the dynamic environment of "loose-suspended-resedimentation" and its matching relationship with particle characteristics. Please see Figure 5 , Figure 6 and Figure 7The inner-outer diameter ratio significantly affects the radial distribution characteristics of hematite and quartz particles, and this effect is clearly particle size-dependent. With increasing inner-outer diameter ratio, 90μm hematite shows a clear settling advantage, exhibiting strong enrichment capacity; the migration of 59μm hematite is more dependent on the inner-outer diameter ratio and secondary circulation matching, making it more sensitive to the inner-outer diameter ratio; in contrast, although the enrichment ratio of 38μm hematite in the inner region gradually increases, it remains consistently low, indicating that adjusting the inner-outer diameter ratio can optimize the migration path and distribution of fine-grained hematite, but is insufficient to fundamentally reverse its strong fluid-following tendency towards outflow. Meanwhile, 38μm quartz is mainly enriched in the outer region in all systems, and its content in the outer region further increases under larger inner-outer diameter ratios, demonstrating a strong outward enrichment trend.

[0051] Step 104: Divide the spiral chute surface radially into multiple target regions under different spiral chute inner-outer diameter ratios. Within each target region, further divide it into multiple radial micro-regions. Using the outer boundary of each radial micro-region as the simulated cutter position, calculate the sorting performance index under different spiral chute inner-outer diameter ratios and different simulated cutter positions based on the hematite-quartz slurry system, flow field dynamics parameters, and particle motion distribution parameters. By subdividing the spiral chute surface radially and setting the outer boundary of the radial micro-region as the simulated cutter position, and simultaneously combining the hematite-quartz slurry system, flow field dynamics parameters, and particle motion distribution parameters, solve for multi-condition sorting performance indexes to simultaneously compare the changing trends of spiral chute sorting performance caused by two types of variables: different spiral chute inner-outer diameter ratios and different simulated cutter positions.

[0052] The hematite-quartz slurry system refers to a solid-liquid two-phase suspension system composed of water, hematite particles, and quartz particles.

[0053] In some implementations, the multiple target regions include an inner edge region, a middle region, and an outer edge region.

[0054] The expression for the radial range of the inner edge region is:

[0055] The expression for the radial range of the intermediate region is:

[0056] The expression for the radial range of the outer edge region is:

[0057] in, Indicates the radial position of the groove surface. Indicates the inner radius of the spiral chute. This indicates the outer radius of the spiral chute.

[0058] In some implementations, the separation performance indicators include at least one of concentrate yield, concentrate iron grade, iron recovery rate, and separation efficiency.

[0059] The formula for calculating concentrate yield is:

[0060] The formula for calculating the iron grade of concentrate is:

[0061] The formula for calculating iron recovery rate is:

[0062] The formula for calculating separation efficiency is:

[0063] in, Indicates the quality of the concentrate. Indicates the quality of the ore supplied. This indicates the mass of iron in the concentrate. This indicates the mass of iron in the ore. Indicates the recovery rate of hematite. This indicates the quartz recovery rate.

[0064] Hematite recovery rate The calculation formula is:

[0065] in, Indicates the mass of hematite in the concentrate. This indicates the mass of hematite in the ore.

[0066] Quartz recovery rate The calculation formula is:

[0067] in, Indicates the quality of quartz in the concentrate. This indicates the mass of quartz in the ore.

[0068] For example, each of the inner, middle, and outer regions can be divided into 5 radial micro-regions, for a total of 15 radial micro-regions on the entire chute surface. The outer boundary of each radial micro-region is used as the location of the simulated ore cutter. The geometric dimensions of the spiral chute surface are shown in Table 2.

[0069] Table 2. Geometric division of spiral chute surface under different ratios of inner and outer diameters.

[0070] The concentrate yield, concentrate iron grade, iron recovery rate, and separation efficiency under different combinations of spiral chute inner and outer diameter ratios and different cross-sectional frame positions in various slurry systems are as follows: Figures 8-11 As shown.

[0071] Step 105: Construct an original decision matrix based on the sorting performance indicators. Perform dimensionless processing on the original decision matrix to obtain a normalized decision matrix. Determine the objective weights of the sorting performance indicators. Couple the normalized decision matrix with the objective weights to obtain a comprehensive performance evaluation index. By constructing the original decision matrix based on the sorting performance indicators and completing the step-by-step operations of dimensionless normalization, objective weight calculation, and matrix weight coupling, a comprehensive performance evaluation index is obtained. This index is used to uniformly quantify the overall sorting quality corresponding to different combinations of spiral chute inner and outer diameter ratios and simulated cutter positions.

[0072] by , ... There are k design schemes as independent variables, with concentrate yield as the primary variable. Iron grade of concentrate Iron recovery rate and separation efficiency A total of four sorting indicators were used as dependent variables to construct the original decision matrix.

[0073] The expression for the original decision matrix is: , in, Represents the original decision matrix. Indicates the ratio of inner to outer diameter is Concentrate yield at that time Indicates the ratio of inner to outer diameter is At that time, the iron grade of the concentrate Indicates the ratio of inner to outer diameter is Iron recovery rate at that time Indicates the ratio of inner to outer diameter is Separation efficiency at that time.

[0074] In some implementations, the range normalization method can be used to eliminate the incommensurability caused by the different dimensions and orders of magnitude among the four sorting indicators, mapping all indicator values ​​to the interval [0, 1]. The expression for the elements in the normalized decision matrix is: , in, This represents the j-th element in the i-th design scheme. This represents the original value of the j-th indicator in the i-th design scheme. and Let these represent the minimum and maximum values ​​of the j-th sorting performance index among all design schemes, respectively. The closer the value is to 1, the better the scheme performs on this metric.

[0075] The expression for the normalized decision matrix is: , Based on the entropy weight method, and according to the dispersion of the data in the normalized decision matrix Z, the weight P of the i-th design scheme under the j-th evaluation index is calculated. ij : , in, This represents the j-th element in the i-th design scheme.

[0076] Calculate the entropy value of the j-th evaluation index. The calculation formula is: , in, The coefficient is the standardized coefficient.

[0077] Calculate the coefficient of variation of the j-th evaluation index. :

[0078] It is the complement of the entropy value. The larger its value, the greater the amount of information provided by the indicator data and the greater its contribution to the multi-dimensional comprehensive evaluation.

[0079] The formula for calculating objective weights is: , in, This represents the objective weight of the j-th evaluation indicator. This represents the coefficient of variation for the j-th indicator. This indicates the number of sorting indicators.

[0080] The expression for the objective weight vector is:

[0081] The objective weight vector satisfies:

[0082] By coupling the normalized index values ​​with objective weights, a single, quantifiable Comprehensive Performance Index (CPI) model for spiral chute performance is established. For the i-th design scheme R... i Its comprehensive performance evaluation index The calculation formula is: , in, Let be the comprehensive performance evaluation index of the i-th design scheme. Evaluation scheme R i The CPI is a single quantitative index for overall sorting performance, with a value range of [0, 1]. A larger CPI value indicates better overall performance of the design scheme across m sorting indicators, meaning it achieves a better balance and overall performance under multi-objective constraints. It should be noted that CPI is not simply an evaluation index, but rather an engineering design criterion used to determine the ratio of the inner and outer diameters of the spiral chute and the radial position of the cutter. A curve showing the relationship between CPI and the inner and outer diameter ratio W is plotted, the peak point of the curve is identified as the global optimum, and the curve's trend reveals the sensitivity of overall performance to design parameters.

[0083] The range normalization method was used to perform dimensionless processing on concentrate yield, concentrate iron grade, iron recovery rate, and separation efficiency. A comprehensive performance evaluation index was constructed using the entropy weight method. The results are shown in Tables 3-5. Figure 12 As shown.

[0084] Table 3. Comprehensive performance evaluation index of spiral chutes with different inner and outer diameter ratios in slurry system A

[0085] Table 4. Comprehensive performance evaluation index of spiral chutes with different inner and outer diameter ratios in slurry system B

[0086] Table 5. Comprehensive performance evaluation index of spiral chutes with different inner and outer diameter ratios in slurry system C

[0087] The comprehensive performance evaluation index-inner diameter ratio (CPI-W) curves for different slurry systems are plotted as follows: Figure 12 As shown in the figure, the preferred W range for slurry system A, representing coarse-grained hematite, is 0.250~0.325, with a further preferred W=0.325. Under this condition, the comprehensive performance evaluation index is optimal, at 0.9410. For slurry systems B, representing intermediate-grained hematite, and C, representing fine-grained hematite, the preferred W range is 0.325~0.475, with a further preferred W=0.400. Under this condition, the comprehensive performance evaluation index is optimal, at 1.0000 and 0.9934 respectively. This indicates that as the particle size of hematite in the material system decreases, increasing the inner-outer diameter ratio is beneficial to improving the comprehensive separation index of the spiral chute.

[0088] Step 106: Determine the ratio of the inner and outer diameters of the spiral chute to match the hematite material based on the comprehensive performance evaluation index.

[0089] Based on the comprehensive performance evaluation index, a matching relationship model and optimization design criteria for multi-particle-size material systems and the inner and outer diameter ratio of spiral chute are constructed, thereby enabling the production of suitable spiral chute sorting equipment for materials of different particle sizes.

[0090] Specifically, based on the median particle size D of the material to be sorted 50 Alternatively, a representative particle size combination can be used to divide the hematite material into several particle size components; the comprehensive performance evaluation index-inner diameter ratio (CPI-W) curve corresponding to each particle size component system can be calculated, and a mapping relationship between the particle size composition and the optimal inner diameter ratio can be established based on the inner diameter ratio corresponding to the peak value of the comprehensive performance evaluation index; the median particle size D... 50 This represents the particle size value corresponding to when the cumulative particle size distribution of mineral particles reaches 50%, indicating that particles larger than and smaller than this value each account for 50%.

[0091] An optimization design criterion for the inner and outer diameter ratio of a spiral chute adapted to the separation of materials of multiple particle sizes is constructed, and the radial position of the appropriate cutter is determined. The cutter is set at the outer boundary of the radial micro-zone and is used to cut off concentrate and tailings. Its position can be adjusted or fixed according to the optimal comprehensive performance evaluation index corresponding to different particle size systems.

[0092] Based on the inner-outer diameter ratio optimization design criterion, the inner-outer diameter ratio corresponding to the maximum value of the comprehensive performance evaluation index is taken as the design value of the inner-outer diameter ratio of the spiral chute, and the outer boundary of the radial micro-zone corresponding to the maximum value of the comprehensive performance evaluation index under this inner-outer diameter ratio condition is taken as the position of the cutter, so as to manufacture a spiral chute sorting equipment adapted to the particle size composition characteristics of the material to be sorted.

[0093] Please see Figure 13 For slurry system A, a spiral chute with W=0.325 was constructed, and for slurry systems B and C, spiral chutes with W=0.400 were constructed.

[0094] This invention also provides a multi-size hematite sorting device, including a spiral chute 1 and a cutter 4. The spiral chute 1 has an inner radius and an outer radius, the ratio of which is determined by the aforementioned method for optimizing the inner and outer diameter ratio of a spiral chute 1 adapted to hematite. The two ends of the spiral chute 1 are a feed port 2 and a discharge port 5, respectively. The cutter 4 is disposed on the chute surface 3 of the spiral chute 1 near the discharge port 5. The cutter 4 is radially positioned along the chute surface 3 at the outer boundary of the radial micro-region determined by the optimization method. Figure 13 The boundary positions of the inner edge region 11, the middle region 12, and the outer edge region 13.

[0095] This invention constructs a gas-liquid-solid multiphase flow numerical calculation model including the Baigno power source term, and combines multiple sets of three-dimensional parametric geometric models for flow field and particle simulation, which can reduce the deviation between the model and the actual slurry system. By combining radial partition micro-area interception measurement and sorting index with objective weights to obtain a comprehensive evaluation index, it can take into account the working conditions of hematite-quartz slurry with different particle sizes, determine the optimal inner and outer diameter ratio of the suitable material, effectively improve the matching degree between structural parameters and hematite sorting conditions, and reduce the adaptation deviation caused by simply relying on a single flow field data for optimization.

[0096] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for optimizing the inner and outer diameter ratio of a spiral chute for multi-size hematite sorting, characterized in that, include: A three-dimensional parametric geometric model including the inner and outer diameter ratio of the spiral chute is constructed. A three-dimensional geometric model of the spiral chute including multiple spiral chutes with different inner and outer diameter ratios is constructed. The three-dimensional geometric model of the spiral chute is discretized to obtain a computational domain mesh. Obtain the material characteristic parameters and sorting operation parameters of the target hematite slurry. Based on the material characteristic parameters and the sorting operation parameters, construct a hematite-quartz slurry system including different particle size combinations, and a gas-liquid-solid multiphase flow numerical calculation model corresponding to the three-dimensional parameterized geometric model. The gas-liquid-solid multiphase flow numerical calculation model includes the Baigno power source term. Based on the computational domain grid and the gas-liquid-solid multiphase flow numerical calculation model, numerical simulations were performed on the clear water flow field and the multiphase flow field of hematite slurry under different spiral chute inner-outer diameter ratios to obtain the flow field dynamic parameters and particle motion distribution parameters under different spiral chute inner-outer diameter ratios. The spiral chute surface under different spiral chute inner-outer diameter ratios is divided into multiple target regions radially. Within each target region, multiple radial micro-regions are further divided. The outer boundary of each radial micro-region is used as the simulated cutter position. Based on the hematite-quartz slurry system, the flow field dynamics parameters, and the particle motion distribution parameters, the sorting performance index is calculated for different spiral chute inner-outer diameter ratios and different combinations of simulated cutter positions. Based on the sorting performance indicators, an original decision matrix is ​​constructed. The original decision matrix is ​​then dimensionless to obtain a normalized decision matrix. The objective weights of the sorting performance indicators are determined. The normalized decision matrix and the objective weights are coupled to obtain a comprehensive performance evaluation index. The ratio of the inner and outer diameters of the spiral chute to that of different hematite materials is determined based on the comprehensive performance evaluation index.

2. The method for optimizing the inner and outer diameter ratio of a spiral chute for multi-size hematite sorting according to claim 1, characterized in that, The formula for calculating the ratio of the inner and outer diameters of the spiral chute is: ， in, Indicates the ratio of the inner and outer diameters of the spiral chute. Indicates the inner radius of the spiral chute. This indicates the outer radius of the spiral chute; the ratio of the inner to outer diameter of the spiral chute ranges from 0.100 to 0.

475.

3. The method for optimizing the inner and outer diameter ratio of a spiral chute for multi-size hematite sorting according to claim 1, characterized in that, The structural parameters of the three-dimensional parametric geometric model include at least one of the following: outer radius, pitch, downsloping angle, parabolic exponent of the cross section, total number of turns, and inner-outer diameter ratio. The material characteristic parameters include at least one of the following: number of particle types, particle size, particle density, particle volume ratio, slurry solids concentration, and feed iron grade. The sorting operation parameters include at least one of the following: inlet flow rate, inlet velocity, and inlet / outlet hydraulic diameter.

4. The method for optimizing the inner and outer diameter ratio of a spiral chute for multi-size hematite sorting according to claim 3, characterized in that, The formula for calculating the inlet velocity is: ， in, Indicates the inlet velocity. S represents the inlet flow rate, and S represents the inlet area. The formula for calculating the hydraulic diameter of the inlet and outlet is: ， in, C represents the hydraulic diameter of the inlet and outlet, and C represents the circumference of the inlet and outlet.

5. The method for optimizing the inner and outer diameter ratio of a spiral chute for multi-size hematite sorting according to claim 1, characterized in that, The numerical calculation models for gas-liquid-solid multiphase flow include the VOF free surface model, the Eulerian Multi Fluid VOF multiphase flow model, and the RNG k-ε turbulence model. In the Eulerian Multi Fluid VOF multiphase flow model, a Begnostic source term is introduced as a source term, which is determined based on the Begnostic number; The formula for calculating the Baigno number is as follows: ， in, Represents the Baigno number, Indicates the linear concentration of particles. d represents particle density. s Indicates particle diameter, Indicates the viscosity of the liquid phase. Indicates the average velocity shear rate; The formula for calculating the linear concentration of the particles is: ， in, This represents the maximum volume fraction of particles in static packing. This indicates the volume concentration of particles.

6. The method for optimizing the inner and outer diameter ratio of a spiral chute for multi-size hematite sorting according to claim 1, characterized in that, The flow field dynamic parameters include at least one of the following: film thickness, mainstream tangential velocity, secondary circulation radial velocity, and turbulent kinetic energy. The particle motion distribution parameters include at least one of the following: cumulative radial flux of particles, particle enrichment rate, and radial distribution characteristics of particles. The formula for calculating the thickness of the flow film is: ， in, Indicates film thickness. Indicates the height of the gas-liquid interface. Indicates the height of the bottom wall of the tank; The formula for calculating the particle enrichment rate is as follows: ， in, Indicates particle enrichment rate. This represents the volume fraction of particles with a certain property in a local mesh. This indicates the volume fraction of particles in the feed.

7. The method for optimizing the inner and outer diameter ratio of a spiral chute for multi-size hematite sorting according to claim 1, characterized in that, The multiple target regions include an inner edge region, a middle region, and an outer edge region; The expression for the radial range of the inner edge region is: ， The expression for the radial range of the intermediate region is: ， The expression for the radial range of the outer edge region is: ， in, Indicates the radial position of the groove surface. Indicates the inner radius of the spiral chute. This indicates the outer radius of the spiral chute.

8. The method for optimizing the inner and outer diameter ratio of a spiral chute for multi-size hematite sorting according to claim 1, characterized in that, The sorting performance indicators include at least one of concentrate yield, concentrate iron grade, iron recovery rate, and separation efficiency; The expression for the original decision matrix is: ， in, Represents the original decision matrix. Indicates the ratio of inner to outer diameter is The concentrate yield value at that time, Indicates the ratio of inner to outer diameter is At that time, the iron grade of the concentrate Indicates the ratio of inner to outer diameter is Iron recovery rate at that time Indicates the ratio of inner to outer diameter is Separation efficiency at that time.

9. The method for optimizing the inner and outer diameter ratio of a spiral chute for multi-size hematite sorting according to claim 1, characterized in that, The expression for the elements in the normalized decision matrix is: ， in, This represents the j-th element in the i-th design scheme. This represents the original value of the j-th indicator in the i-th design scheme. and Let represent the minimum and maximum values ​​of the j-th sorting performance index among all design schemes, respectively; The formula for calculating the objective weight is: ， in, This represents the objective weight of the j-th evaluation indicator. This represents the coefficient of variation for the j-th indicator. Indicates the number of sorting indicators; The formula for calculating the comprehensive performance evaluation index is as follows: ， in, Let be the comprehensive performance evaluation index of the i-th design scheme.

10. A multi-size hematite sorting equipment, characterized in that, Includes spiral chute and ore cutter; The spiral chute has an inner radius and an outer radius, and the ratio of the inner radius to the outer radius is determined by the inner-outer diameter ratio optimization method of the multi-grain size hematite sorting spiral chute according to any one of claims 1-9. The two ends of the spiral chute are the feed port and the discharge port, respectively. The cutter is set on the chute surface near the discharge port. The cutter is set radially along the chute surface at the outer boundary of the radial micro-region determined by the optimization method.

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