A step-by-step optimization method and test equipment for spiral chute cross-section geometric parameters

Abstract

The present invention provides a method and test equipment for gradually optimizing the cross-sectional geometric parameters of a spiral chute, comprising the following steps: based on the changing trend of the particle separation index when the continuous curve cross-sectional geometric parameters are adjusted, confirming the optimization range of the lower bevel angle and the cross-sectional curve function; based on the interactive influence of the lower bevel angle and the cross-sectional curve function on the particle separation efficiency, determining the optimal continuous curve cross-sectional geometric parameter configuration mode; according to the particle distribution and separation efficiency curve in the optimal continuous curve cross-section, determining the range of the particle easy-to-mix region, and locally designing the cross-sectional geometry of this region; respectively adjusting the lateral inclination angles of different line segments in the particle easy-to-mix region, and confirming the independent regulation effect of the local cross-sectional geometric parameters on the separation result based on the particle migration behavior and the changing law of the spiral chute separation performance; based on the response surface analysis method, establishing the optimal local cross-sectional geometric parameter configuration mode when the lateral inclination angles of different line segments act in synergy; and manufacturing the spiral chute test equipment based on the above optimization method.

Description

Technical Field

[0001] The invention belongs to the technical field of composite force field ore dressing equipment and relates to a method for gradually optimizing the cross-section geometric parameters of a spiral chute and a test device. Background Art

[0002] Building green mines is an important measure to promote ecological civilization construction in the mining industry and improve the efficiency of comprehensive resource utilization. As a typical film dressing equipment based on the combined action of gravity and centrifugal inertia, spiral chute is widely used in the separation of iron, tungsten, tin, tantalum, niobium, coal, seashore sand and other non-ferrous metals, rare metals and non-metallic minerals with different densities due to its many unique advantages.

[0003] The applicant team's preliminary research found that the cross-sectional geometry of the spiral chute is an important factor affecting fluid dynamics parameters such as film thickness, mainstream average velocity, secondary circulation, and Reynolds number, which in turn determines the movement behavior of particles in the flow field and the separation effect. In the actual operation process, once the structural parameters of the spiral chute such as diameter, cross-sectional geometry, and pitch are selected, it is difficult to adjust them. At this time, the production indicators can be optimized by adjusting the operating parameters, but the improvement is not large. In view of this, it is urgent to develop a method for the design of spiral chute structural parameters, especially cross-sectional geometry parameters, and strive to explain the separation effect from a theoretical perspective, so as to achieve precise control of the separation process of particles with different properties, and provide reference and reference for improving the quality and efficiency of spiral chute industrial production.

[0004] At present, the methods used for spiral chute cross-section geometry optimization and test equipment design include theoretical research, physical testing and numerical simulation. Theoretical research ignores the interaction between particles to varying degrees, and greatly simplifies the particle motion, resulting in a large difference between the predicted results of the theoretical model and the actual results. Flow field and particle testing equipment such as Laser Doppler Anemometry (LDA), Particle Image Velocimetry (PIV) and Positron Emission Particle Tracking (PEPT) can obtain fluid and particle motion information without invading the flow field, but there are shortcomings such as cumbersome detection process, harsh test conditions and high maintenance costs. Numerical simulation methods have the advantages of low cost, short cycle and comprehensive process parameter information. In recent years, they have been widely used in the development of mineral processing equipment, providing more possibilities for developing a method and test equipment for step-by-step optimization of spiral chute cross-section geometry parameters from the perspective of fluid dynamics.

[0005] The cross-sectional geometry of spiral chutes is usually controlled by cubic parabola, elliptic curve or combined curve function. A large number of cross-sectional curves can be generated by changing the function expression. It is undoubtedly very difficult to select the best cross-sectional curve suitable for sorting different materials. Currently, it is generally screened by trial and error tests, which consumes a lot of manpower and material costs. In addition, although the cross-sectional curves currently used in production or research can achieve good sorting effects, how to explain the sorting results from the perspective of particle migration process is not well explored, and the design and optimization methods of local geometric parameters for the easy mixing area of ​​particles are rarely paid attention to. Summary of the invention

[0006] In order to solve the above problems, the technical solution adopted by the present invention is: a method for gradually optimizing the cross-sectional geometric parameters of a spiral chute and a test device, comprising the following steps:

[0007] S1, based on the high-precision spiral chute flow field and particle field calculation model, the particle separation numerical test is carried out, and the optimization range of the lower slope angle and the cross-section curve function is confirmed based on the change trend of the particle separation index when the geometric parameters of the continuous curve section are adjusted;

[0008] S2, based on the interactive influence of the down-slope angle and the cross-section curve function on the separation performance of the spiral chute, determine the optimal continuous curve cross-section geometric parameter configuration method;

[0009] S3, according to the particle distribution curve under the condition of the optimal continuous curve cross-sectional geometric parameters, determine the range of the particle easy mixing area, and perform local design of the cross-sectional geometry of this area;

[0010] S4, respectively adjust the lateral inclination angles of different line segments in the particle easy-to-mix area, and confirm the independent regulation effect of local parameters on the separation results based on the particle migration behavior and the change law of the spiral chute separation performance;

[0011] S5, based on the response surface analysis method, the separation index when the lateral inclination angles of different line segments work together is confirmed, and the optimal local section geometric parameter configuration method is established.

[0012] Further: Based on the high-precision spiral chute flow field and particle field calculation model, the particle separation numerical test is carried out, and based on the change trend of the particle separation index when the continuous curve section geometric parameters are adjusted, the process of confirming the optimization range of the lower bevel angle and the section curve function is as follows:

[0013] Based on the structural parameters and the cross-section curve function expression, the function image of the third quadrant in the Cartesian coordinate system is selected as the cross-section geometry of the spiral chute;

[0014] Based on the adjustment strategy of the lower oblique angle and the cross-sectional curve function and the experimental conditions of feed flow rate and feed solid mass concentration, a spiral chute geometric model was constructed according to the corresponding cross-sectional geometric parameters, and a total of A group of numerical tests were carried out to examine the change trends of the separation efficiency of two different particles when the lower oblique angle and the cross-sectional curve function were adjusted.

[0015] Based on when the separation efficiency peak reaches the threshold, the range of the downslope angle and cross-section curve function are confirmed respectively.

[0016] Furthermore: the threshold value is 80% of the peak separation efficiency.

[0017] Further: the process of determining the optimal continuous curve section geometric parameter configuration method based on the interactive influence of the lower slope angle and the section curve function on the separation performance of the spiral chute is as follows:

[0018] Numerical tests were conducted based on the interactive effects of the down-slope angle and the cross-section curve function on the separation performance of the spiral chute.

[0019] From the test results of the interactive effects of the lower inclination angle and the cross-sectional curve function on the maximum separation efficiency, the lower inclination angle and the cross-sectional curve function for the best separation performance of the spiral chute are confirmed when the vertical coordinate of the separation efficiency is the highest, and then the control equation of the optimal continuous curve cross-sectional geometry is obtained.

[0020] Further: the process of determining the particle easy-mixing region range according to the particle distribution curve under the optimal continuous curve cross-sectional geometric parameter conditions and performing local design of the cross-sectional geometry of this region is as follows:

[0021] Based on the distribution characteristics and separation efficiency curve of the two different particles in the final groove surface of the third spiral chute, the separation efficiency curve has a sharp peak and the mismatch between the two particles is large, and the easy mixing area of ​​the two different particles is confirmed;

[0022] Divide the particle miscibility region curve into M segments;

[0023] The curve is divided into M segments, and the line segment between the two end points is used to approximate the original curve, thus obtaining M line segments.

[0024] Further: the process of adjusting the lateral inclination angles of different line segments in the particle easy-to-mix area respectively and confirming the independent regulation effect of local parameters on the separation result based on the particle migration behavior and the change law of the spiral chute separation performance is as follows:

[0025] The spiral chute geometric models were constructed based on the transverse inclination design values ​​of M line segments, and the radial migration behavior of particles was quantitatively characterized by the cumulative net radial flux during the particle separation process using numerical experimental methods, thus fundamentally revealing the particle separation mechanism.

[0026] The particle separation efficiency at different radial positions on the last groove surface of the third spiral chute was calculated to determine the lateral inclination range of each line segment when high separation performance was achieved.

[0027] Furthermore: the lateral inclination design value is adjusted based on a local line segment lateral inclination adjustment strategy, wherein the local line segment lateral inclination adjustment strategy uses a line segment between two end points to approximate a curve, and adjusts based on the lateral inclination of M line segments as a reference or center.

[0028] Further: the process of confirming the separation index when different line segment lateral inclination angles work together based on the response surface analysis method and establishing the optimal local section geometric parameter configuration method is as follows:

[0029] According to the Box-Beknhen Design experimental design principle, a three-level response surface experiment was designed with the lateral inclination angles of M line segments as independent variables and separation efficiency as response value.

[0030] Based on the separation efficiency test values ​​obtained by numerical simulation under Box-Beknhen Design, multiple regression fitting analysis was performed to establish a regression model.

[0031] Perform variance analysis and significance test on the multiple regression model;

[0032] Based on the synergistic effect of the M line segments when the lateral inclination angles are adjusted, the line segments and their combinations among the M line segments whose lateral inclination angles have the most significant effect on the separation efficiency are identified;

[0033] The regression model is solved to determine the optimal lateral inclination angle of the local line segment to obtain the maximum separation efficiency.

[0034] The present invention provides a method and test equipment for gradually optimizing the cross-sectional geometric parameters of a spiral chute, which has the following advantages: the optimal configuration of the continuous curve cross-sectional geometric parameters of the spiral chute and the optimal configuration of the local cross-sectional geometric parameters for the easily mixed particle area are achieved step by step, and then the spiral chutes are respectively manufactured according to the two optimized cross-sections and the actual separation performance is tested, the reliability and scientificity of the numerical test and the step-by-step optimization method are verified, and the spiral chute test equipment for efficient sorting of designated materials is obtained. The optimization method and equipment formed by the present invention can provide a set of efficient test methods for the cross-sectional structural design of the spiral chute, and adopt a three-turn short-stroke spiral chute geometric model for structural research and development design, which helps to simplify the test process and improve design efficiency.

[0035] The effect of the present invention is that the spiral chute cross-sectional geometric parameter step-by-step optimization method and test equipment provided by the present invention, through the numerical test, the control effect and interactive influence of the continuous curve cross-sectional geometric parameters on the particle separation index are determined, and the optimal configuration mode of the continuous curve cross-sectional geometric parameters is determined; the local design concept for the cross-sectional geometry of the particle easy-to-mix area is proposed, and the independent control effect of the local line segment lateral inclination angle on the spiral chute separation performance is found out, and the synergistic effect of the lateral inclination angles of different line segments is examined by means of the response surface analysis method, and the optimal configuration mode of the local cross-sectional geometric parameters is established. The spiral chute test equipment provided by the present invention realizes the efficient sorting of the specified materials, and analyzes the fundamental reason why the particles obtain the index improvement in a short stroke after the cross-sectional geometric parameters are gradually optimized from the perspective of the separation process, and verifies the reliability and effectiveness of the numerical method and the cross-sectional geometric parameter optimization method. The present invention reduces the number of spiral chute turns, which can reduce equipment costs and save installation space for actual production; for research work, it can shorten the time of numerical calculation. The present invention provides a set of efficient methods for the cross-sectional structure design of the spiral chute, and provides an effective way to accurately control the separation effect of mineral particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0037] Figure 1 is a flow chart of the method;

[0038] Figure 2 It is a schematic diagram of the cross-sectional shape of the spiral chute;

[0039] Figure 3 The figure shows the influence of the geometric parameters of the continuous curve section on the particle separation efficiency; (a) is the influence of the lower slope angle; (b) is the influence of the section curve function;

[0040] Figure 4 is the interactive influence diagram of the lower slope angle and the cross-section curve function on the maximum separation efficiency;

[0041] Figure 5 It is the yield distribution and separation efficiency diagram of hematite and quartz at the end of the third cycle, where (a) is the yield distribution; (b) is the separation efficiency;

[0042] Figure 6 It is the geometric division diagram of the cross section of the particle easy mixing area;

[0043] Figure 7The effect of the lateral inclination angle of region (I) on the cumulative net radial flux of particles at r = 80 mm, where (a) hematite; (b) quartz;

[0044] Figure 8 is the effect of the lateral inclination angle of the (II) region on the cumulative net radial flux of particles at r = 100 mm, where (a) hematite; (b) quartz;

[0045] Fig. 9 is the effect of the lateral inclination angle of the (III) region on the cumulative net radial flux of particles at r = 120 mm, where (a) hematite; (b) quartz;

[0046] Fig.10 It is the effect of local adjustment of lateral inclination angle on the separation performance of spiral chute; among them, (a) (Ⅰ) area; (b) (Ⅱ) area; (c) (Ⅲ) area;

[0047] Fig.11 Figure 1 is a diagram of a spiral chute test equipment. (a) is the optimal continuous curve section spiral chute; (b) is the optimal local line section spiral chute;

[0048] Fig.12 It is a visual connection diagram of the spiral chute separation test system;

[0049] Fig.13 This is a comparison of the separation efficiency of two spiral chutes at different cutter positions, (a) the optimal continuous curve section; (b) the optimal local line segment section;

[0050] Fig.14 These are the cumulative net radial flux variation curves of particles in spiral chutes with different cross-sections, (a) r = 80 mm; (b) r = 100 mm; (c) r = 120 mm. DETAILED DESCRIPTION

[0051] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0052] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] A method and test equipment for gradually optimizing the cross-sectional geometric parameters of a spiral chute, the technical route of which is as follows Figure 1 As shown, the following steps are included:

[0054] S1, based on the high-precision spiral chute flow field and particle field calculation model, the particle separation numerical test is carried out, and the optimization range of the lower slope angle and the cross-section curve function is confirmed based on the change trend of the particle separation index when the geometric parameters of the continuous curve section are adjusted;

[0055] S2, based on the interactive influence of the down-slope angle and the cross-section curve function on the separation performance of the spiral chute, determine the optimal continuous curve cross-section geometric parameter configuration method;

[0056] S3, according to the particle distribution curve under the condition of the optimal continuous curve cross-sectional geometric parameters, determine the range of the particle easy mixing area, and perform local design of the cross-sectional geometry of this area;

[0057] S4, respectively adjust the lateral inclination angles of different line segments in the particle easy-to-mix area, and confirm the independent regulation effect of local parameters on the separation results based on the particle migration behavior and the change law of the spiral chute separation performance;

[0058] S5, based on the response surface analysis method, the separation index when the lateral inclination angles of different line segments work together is confirmed, and the optimal local section geometric parameter configuration method is established.

[0059] Further: Based on the high-precision spiral chute flow field and particle field calculation model, the particle separation numerical test is carried out, and based on the change trend of the particle separation index when the continuous curve section geometric parameters are adjusted, the process of confirming the range of the lower slope angle and the section curve function is as follows:

[0060] Based on the structural parameters and the cross-section curve function expression, the function image of the third quadrant in the Cartesian coordinate system is selected as the cross-section geometry of the spiral chute;

[0061] Based on the adjustment strategy of the lower inclination angle and the cross-sectional curve function and the experimental conditions of the feed flow rate and the feed solid mass concentration, a spiral chute geometric model was constructed according to the corresponding cross-sectional geometric parameters, and a total of A groups of numerical experiments were carried out to examine the changing trends of the separation efficiency of two different particles when the lower inclination angle and the cross-sectional curve function were adjusted. This application has no specific requirements for the two different particle sizes and densities; it is suitable for the spiral chute to separate any particle size within the suitable size range (-2mm) and particle groups with density differences.

[0062] The cross-section curve function adjustment strategy refers to: a method for adjusting coefficients and exponents of the cross-section curve function expression;

[0063] Based on when the separation efficiency peak reaches the threshold, the range of the downslope angle and cross-section curve function are confirmed respectively.

[0064] Furthermore: the threshold value is 80% of the peak separation efficiency.

[0065] Further: the process of determining the optimal continuous curve section geometric parameter configuration method based on the interactive influence of the lower slope angle and the section curve function on the separation performance of the spiral chute is as follows:

[0066] Numerical tests were conducted based on the interactive effects of the down-slope angle and the cross-section curve function on the separation performance of the spiral chute;

[0067] From the test results of the interactive effects of the lower inclination angle and the cross-sectional curve function on the maximum separation efficiency, the lower inclination angle and the cross-sectional curve function for the best separation performance of the spiral chute are confirmed when the vertical coordinate of the separation efficiency is the highest, and then the control equation of the optimal continuous curve cross-sectional geometry is obtained.

[0068] Further: the process of determining the particle easy-mixing region range according to the particle distribution curve under the optimal continuous curve cross-sectional geometric parameter conditions and performing local design of the cross-sectional geometry of this region is as follows:

[0069] Based on the distribution characteristics and separation efficiency curve of the two different particles in the final groove surface of the third circle of the spiral chute, the sharp peak of the separation efficiency curve and the large mismatch of the two particles confirmed the range of the easy mixing area of ​​the two different particles; because the separation process of the particles mainly occurs in the first circle, and then gradually tends to be stable, there is still a certain relative movement trend in the 1st to 3rd circles, so the indicators in the groove surface of 0 to 3 circles cannot accurately describe the separation results; selecting the separation results in the final groove surface of the 3rd circle with better flow parameters and particle movement stability as the evaluation index is more representative.

[0070] Divide the particle miscibility region curve into M segments;

[0071] The curve is divided into M segments, and the line segment between the two end points is used to approximate the original curve, thus obtaining M line segments.

[0072] Further: the process of adjusting the lateral inclination angles of different line segments in the particle easy-to-mix area respectively and confirming the independent regulation effect of local parameters on the separation result based on the particle migration behavior and the change law of the spiral chute separation performance is as follows:

[0073] The geometric models of the spiral chute were constructed based on the design values ​​of the lateral inclination angles of M line segments. The radial migration behavior of the particles was quantitatively characterized by the cumulative net radial flux during the particle separation process using a numerical experimental method, thus fundamentally revealing the particle separation mechanism.

[0074] The distribution of particle separation efficiency in the final groove surface of the third circle of the spiral chute was calculated, and the lateral inclination range of each line segment when high separation performance was achieved was obtained. Because the particle separation process mainly occurs in the first circle, and then gradually stabilizes, there is still a certain relative movement trend in the first to third circles, so the indicators in the groove surface of 0 to 3 circles cannot accurately describe the separation results; it is more representative to select the separation results in the final groove surface of the third circle with better flow parameters and particle movement stability as the evaluation indicators.

[0075] There is no fixed quantitative standard for the so-called higher. It is selected by comparing the separation efficiencies corresponding to different lateral inclination angles of the M line segments.

[0076] Further: the lateral inclination design value is adjusted based on the local line segment lateral inclination adjustment strategy, the local line segment lateral inclination adjustment strategy uses the line segment between the two end points to approximate the curve, and uses the lateral inclination of the M line segments as the reference or center for adjustment. Since the lateral inclination of the original continuous section curve in the particle easy mixing area has a small change range, the line segment between the two end points is used to approximate the curve, and the lateral inclination of the M line segments is used as the reference or center for adjustment.

[0077] Further: the process of confirming the separation index when different line segment lateral inclination angles work together based on the response surface analysis method, establishing the optimal local section geometric parameter configuration method, and obtaining the optimal geometric parameters of the spiral chute section is as follows:

[0078] According to the Box-Beknhen Design experimental design principle, a three-level response surface experiment was designed with the lateral inclination angle of M line segments as the independent variable and the separation efficiency as the response value to find out the significance of the influence of the lateral inclination angle of M line segments and their synergistic effect on the separation efficiency and to determine the optimal lateral inclination angle of M line segments.

[0079] Based on the separation efficiency test values ​​obtained by numerical simulation under Box-Beknhen Design, multiple regression fitting analysis was performed, and the regression model was established using Design-Expert software.

[0080] Perform variance analysis and significance test on the multiple regression model;

[0081] Based on the synergistic effect of the M line segments when the lateral inclination angles are adjusted, the line segments and their combinations among the M line segments whose lateral inclination angles have the most significant effect on the separation efficiency are identified;

[0082] Solve the regression model to determine the optimal lateral inclination angle of the local segment when the separation efficiency is maximum.

[0083] Based on the above-mentioned method for gradually optimizing the geometric parameters of the cross-section of a spiral chute, the geometric parameters of the optimal continuous curve cross-section and the optimal local line segment cross-section of the spiral chute were determined. The geometric models of the two spiral chutes were drawn separately using SolidWorks software, and then the test equipment was produced by 3D printing.

[0084] Embodiment 1: A method and test equipment for gradually optimizing the cross-sectional geometric parameters of a spiral chute, comprising the following steps:

[0085] S1, based on the high-precision spiral chute flow field and particle field calculation model, the particle separation numerical test is carried out under the conditions of appropriate spiral chute structural parameters and operating parameters, the change trend of particle separation index when the continuous curve section geometric parameters are adjusted is examined, and the regulating effect of the above parameters is determined;

[0086] The structural parameters include: diameter Pitch P, number of turns N, cross-section curve function, lower inclination angle γ, lateral inclination angle β;

[0087] The diameter Pitch P = 240 mm, number of turns N = 3;

[0088] The cross-section curve function expression is:

[0089] |x|=m|y| n

[0090] In the formula, m is the coefficient of the cross-sectional curve function, and n is the exponent of the cross-sectional curve function;

[0091] The function graph of the third quadrant in the Cartesian coordinate system is selected as the cross-sectional geometry of the spiral chute, such as Figure 2 ;

[0092] The lower bevel angle γ is the acute angle formed by the line connecting the inner and outer edge endpoints and the horizontal line, and the calculation formula is:

[0093] tanγ=[m 1 / n (R 0 ) 1-1 / n ] -1

[0094] Where R is the outer radius, r 0 is the inner radius;

[0095] The lateral inclination angle β is the acute angle formed by the tangent line at a certain radial position r of the cross-section curve and the horizontal line;

[0096] The operating parameters include: feed flow rate of 8 L / min, feed solid mass concentration of 20%;

[0097] The particle properties are set as follows: the particle size of the target mineral hematite and the gangue mineral quartz are both 89.5 μm, and the density is 4950 kg / m 3 and 2650kg / m 3 , the mass ratio is 1.87:1, and the feed iron grade is 45.59%.

[0098] Table 1 Section curve function expression

[0099]

[0100] Furthermore, the spiral chute geometric model was constructed according to the corresponding cross-section geometric parameters, and a total of 9 groups of numerical experiments were carried out to examine the change trend of the separation efficiency of 89.5 μm quartz and hematite when the lower inclination angle was 3°, 6°, 9°, 12°, and 15° and the cross-section curve function was adjusted (Table 1). The results are shown in Figure 3 As shown, (a) is the influence of the lower slope angle; (b) is the influence of the cross-section curve function;

[0101] from Figure 3 It can be found that appropriately increasing the downward oblique angle of the curve and the cross-section curve function index are beneficial to improving the separation efficiency of hematite and quartz particles. When the downward oblique angle is 6° and 9° or the cross-section curve function index is 2.5-3.5, the separation efficiency peak can reach about 80%, and the separation effect is better.

[0102] S2, examine the interactive effects of the lower inclination angle and the cross-section curve function on the separation performance of the spiral chute, and determine the optimal configuration of the continuous curve cross-section geometric parameters;

[0103] Furthermore, numerical experiments were conducted to investigate the interactive effects of the lower inclination angle and the cross-sectional curve function on the separation performance of the spiral chute. The experimental results are shown in Figure 2. Figure 4 shown.

[0104] When the downward inclination angle is 6° and the cross-section curve function index is 2.5, the separation performance is optimal, and the maximum separation efficiency is 82.02%.

[0105] Furthermore, the above conditions are defined as the optimal continuous curve section, and the control equation of the section curve is:

[0106] |x|=0.212|y| 2.5

[0107] S3, according to the particle distribution curve under the condition of the optimal continuous curve cross-sectional geometric parameters, determine the range of the particle easy mixing area, and perform local design of the cross-sectional geometry of this area;

[0108] Furthermore, the yield distribution and separation efficiency of hematite and quartz in the final slot of the third spiral chute were investigated. Figure 5As shown, (a) is the yield distribution; (b) is the separation efficiency. It can be found that hematite and quartz form selective distribution and enrichment in the groove surface, and the maximum separation efficiency appears at the cut-off position of 100 mm. However, the yield of mixed quartz in the narrow interval near the radial position of 70 mm is significantly higher, and there is also a lot of hematite mixed in the quartz aggregation area of ​​100-115 mm. At the same time, the peak of the separation efficiency curve is sharp, and the decline is obvious in the 100-130 mm area. The adaptation range of the cut-off position is narrow, so the radial interval of 70-130 mm is uniformly defined as the particle easy mixing area, and local design is performed on it later.

[0109] Furthermore, the particle easy mixing region curve is divided into three sections: region (I) (r=70-90 mm), region (II) (r=90-110 mm) and region (III) (r=110-130 mm), and r=80 mm, r=100 mm and r=120 mm are used as the characteristic radial positions of regions (I) to (III), respectively.

[0110] Furthermore, since the lateral inclination angles of the curves in the above three regions vary slightly, the line segments between the two end points are used to approximate the original curves, that is, P 1 P 2 , P 2 P 3 and P 3 P 4 Three line segments, such as Figure 6 As shown;

[0111] S4, respectively adjust the lateral inclination angles of different line segments in the particle easy-to-mix area, examine the particle migration behavior and the change law of the spiral chute separation performance, and determine the independent regulation effect of local parameters on the separation results;

[0112] Furthermore, the spiral chute geometric models were constructed according to the transverse inclination design values ​​shown in Table 2, and the particle separation process was examined using the numerical test method. The separation results are shown in Table 2. Figure 7 , Figure 8 and Fig. 9 shown.

[0113] Figure 7 The effect of the lateral inclination angle of region (I) on the cumulative net radial flux of particles at r = 80 mm, where (a) hematite; (b) quartz;

[0114] Figure 8 is the effect of the lateral inclination angle of the (II) region on the cumulative net radial flux of particles at r = 100 mm, where (a) hematite; (b) quartz;

[0115] Fig. 9is the effect of the lateral inclination angle of the (III) region on the cumulative net radial flux of particles at r = 120 mm, where (a) hematite; (b) quartz;

[0116] Table 2 Local segment lateral inclination adjustment strategy

[0117]

[0118] The results show that in the slots with different transverse inclination angles, as the number of flow turns increases, the hematite particles migrate outward first and then inward, and the amount of inward migration increases continuously. The larger the transverse inclination angle of the slot surface, the shorter the distance to inward movement, and the larger the cumulative net radial flux. However, when the transverse inclination angle is too large, the amount of inward migration of hematite in the stable stage tends to decrease. Therefore, appropriately increasing the transverse inclination angle can promote the inward migration of hematite, but it should not be too large. The increase in the transverse inclination angle in regions (Ⅰ) and (Ⅱ) has a greater positive regulatory effect on the inward movement of hematite particles. The cumulative net radial flux of quartz is positive, indicating that its migration direction continues to be outward, and its migration amount is negatively correlated with the transverse inclination angle.

[0119] Furthermore, the distribution of particle separation efficiency in the final groove surface of the third spiral chute is calculated. The results are as follows: Fig.10 As shown, (a) is region (I); (b) is region (II); (c) is region (III);

[0120] It can be seen that as the lateral inclination angle of each line segment increases, the optimal interceptor position gradually moves inward, and when higher separation performance is achieved, the lateral inclination angle ranges of each line segment are 5-9°, 3-5°, and 2-6°, respectively.

[0121] S5, based on the response surface analysis method, the separation index of different line segment transverse inclination angles was examined to establish the optimal local section geometric parameter configuration method;

[0122] Furthermore, based on the results of the effect of the local segment lateral inclination angle on the separation performance of the spiral chute, according to the Box-Behnken Design experimental design principle, (I) the regional lateral inclination angle (X 1 ), (II) Regional lateral inclination (X 2 ) and (III) the lateral inclination of the region (X 3 ) was used as the independent variable, and the response surface experiment was designed with separation efficiency as the response value. The factors and level settings are shown in Table 3. The experimental levels of the independent variables were coded as -1, 0, and 1, respectively. A total of 17 experimental points were designed. The specific experimental scheme and numerical simulation results are shown in Table 4.

[0123] Table 3 Response surface analysis factors and levels

[0124]

[0125] Table 4 Box-Beknhen Design experimental design and results

[0126]

[0127] Furthermore, multiple regression fitting analysis was performed on the data in Table 4, and the following regression model was obtained:

[0128] Y=83.86+1.35X 1 +1.4X 2 -0.8062X 3 +0.3425X 1 X 2 +2.64X 1 X 3 -0.985X 2 X 3 -7.46X 1 2 -

[0129] 5.71X 2 2 -3.97X 3 2

[0130] Furthermore, the multiple regression model was subjected to variance analysis and significance test, and the results are shown in Table 5. Among the single factors, the influence of the lateral inclination angles of region (I) and region (II) was highly significant, which was consistent with the significance of the influence of the lateral inclination angle when adjusted independently. Among the interaction terms, the interaction effect of the lateral inclination angles of region (I) and region (III) was the most significant.

[0131] Table 5 Regression analysis of variance

[0132]

[0133] Note: Determination coefficient R 2 is 0.9903; Correction coefficient Adjusted R 2 Adj It is 0.9779; *: p<0.05, significant; **: p<0.01, extremely significant.

[0134] Furthermore, by solving the regression model, it was determined that the optimal lateral inclination angles of the local segments were 6.40°, 4.43°, and 3.59°, respectively. The predicted value of the maximum separation efficiency obtained under this condition was 83.26%, which was 1.24 percentage points higher than the maximum separation efficiency (82.02%) achieved by the optimal continuous curved section spiral chute. At the same time, the optimal lateral inclination angle of each segment was consistent with the appropriate range determined by the single factor independent influence test.

[0135] S6, according to the above step-by-step optimization results, respectively manufacture the optimal continuous curve section spiral chute and the optimal local line section spiral chute test equipment, and perform separation performance testing and comparison;

[0136] Furthermore, we customize the spiral chute test equipment with the best continuous curve section and the best local line section. The actual picture is as follows: Fig.11 As shown, (a) is the optimal continuous curve cross-section spiral chute; (b) is the optimal local line segment cross-section spiral chute;

[0137] And through Fig.12 The test system shown is used to conduct actual separation tests of hematite and quartz.

[0138] The separation results are as follows Fig.13 As shown. Among them, (a) is the optimal continuous curve section; (b) is the optimal local line segment section;

[0139] Depend on Fig.13 It can be seen that as the position of the cutter moves outward, the two optimized spiral chute test equipments both achieve higher separation efficiency, and show the same change trend as the numerical simulation prediction results. Under the same test conditions, the separation performance of the spiral chute with the optimal local segment section is higher than that of the spiral chute with the optimal continuous curve section, and its separation efficiency curve has a flatter peak, which is conducive to adjusting the position of the cutter and facilitating the regulation and maintenance of production indicators.

[0140] S7, compares and analyzes the cumulative net radial flux of particles in the spiral chute with the optimal continuous curve section and the optimal local line segment section, and analyzes the fundamental reason for the improvement of particle separation index after local optimization of section geometric parameters from a process perspective.

[0141] Furthermore, the changes in the cumulative net radial flux of particles at three representative radial positions are examined, such as Fig.14 shown. Fig.14 These are the cumulative net radial flux variation curves of particles in spiral chutes with different cross-sections, (a) r = 80 mm; (b) r = 100 mm; (c) r = 120 mm.

[0142] The results show that after local optimization of the cross-sectional geometric parameters, the inward migration of hematite in regions (Ⅰ) and (Ⅱ) increases significantly, which improves the separation efficiency of hematite and quartz. The radial migration of quartz in region (Ⅲ) does not change much, while the outward migration of hematite in the first cycle decreases significantly, which is beneficial to improving the separation efficiency in the early stage of flow field evolution and shortening the particle separation stroke.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements 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 gradually optimizing the cross-sectional geometric parameters of a spiral chute, characterized in that: The following steps are involved: S1, based on the high-precision spiral chute flow field and particle field calculation model, the particle separation numerical test is carried out, and the optimization range of the lower slope angle and the cross-section curve function is confirmed based on the change trend of the particle separation index when the geometric parameters of the continuous curve section are adjusted; S2, based on the interactive influence of the down-slope angle and the cross-section curve function on the separation performance of the spiral chute, determine the optimal continuous curve cross-section geometric parameter configuration method; S3, according to the particle distribution curve under the condition of the optimal continuous curve cross-sectional geometric parameters, determine the range of the particle easy mixing area, and perform local design of the cross-sectional geometry of this area; S4, respectively adjust the lateral inclination angles of different line segments in the particle easy-to-mix area, and confirm the independent regulation effect of local parameters on the separation results based on the particle migration behavior and the change law of the spiral chute separation performance; S5, based on the response surface analysis method, confirm the separation index when different line segment lateral inclination angles work together, and establish the optimal local section geometric parameter configuration method; The process of conducting a particle separation numerical test based on the high-precision spiral chute flow field and particle field calculation model and confirming the optimization range of the lower bevel angle and the cross-section curve function based on the change trend of the particle separation index when the continuous curve section geometric parameters are adjusted is as follows: Based on the structural parameters and the cross-section curve function expression, the function image of the third quadrant in the Cartesian coordinate system is selected as the cross-section geometry of the spiral chute; Based on the adjustment strategy of the lower oblique angle and the cross-sectional curve function and the experimental conditions of feed flow rate and feed solid mass concentration, a spiral chute geometric model was constructed according to the corresponding cross-sectional geometric parameters, and a total of A group of numerical tests were carried out to examine the change trends of the separation efficiency of two different particles when the lower oblique angle and the cross-sectional curve function were adjusted. Based on when the separation efficiency peak reaches a threshold, the optimization ranges of the lower slope angle and the cross-section curve function are respectively confirmed; The process of determining the optimal continuous curve section geometric parameter configuration method based on the interactive influence of the lower slope angle and the section curve function on the separation performance of the spiral chute is as follows: Numerical tests were conducted based on the interactive effects of the down-slope angle and the cross-section curve function on the separation performance of the spiral chute; From the test results of the interactive effects of the lower slope angle and the cross-section curve function on the maximum separation efficiency, the lower slope angle and the cross-section curve function when the separation efficiency is the highest are determined, and the control equation of the optimal continuous curve cross-section geometry is obtained; The process of determining the particle easy mixing area range according to the particle distribution curve under the optimal continuous curve cross-sectional geometric parameter conditions and performing local design of the cross-sectional geometry of this area is as follows: Based on the distribution characteristics and separation efficiency curve of the two different particles in the final groove surface of the third spiral chute, the easy-to-mix region of the two particles was confirmed according to the sharp peak of the separation efficiency curve and the large mismatch of the two particles. Divide the particle miscibility region curve into M segments; The curve divided into M segments is approximated by using the line segment between the two end points to replace the original curve, thus obtaining M line segments; The process of adjusting the lateral inclination angles of different line segments in the particle easy-to-mix area respectively and confirming the independent regulation effect of local parameters on the separation results based on the particle migration behavior and the change law of the spiral chute separation performance is as follows: The spiral chute geometric models were constructed based on the transverse inclination design values ​​of M line segments, and the radial migration behavior of particles was quantitatively characterized by the accumulated net radial flux during the particle separation process using numerical experimental methods to reveal the particle separation mechanism. Calculate the particle separation efficiency at different radial positions on the final groove surface of the third spiral chute, and determine the lateral inclination range of each line segment when achieving high separation performance; The process of confirming the separation index when different line segment lateral inclination angles work together based on the response surface analysis method, establishing the optimal local section geometric parameter configuration method, and obtaining the optimal geometric parameters of the spiral chute section is as follows: According to the Box-Beknhen Design experimental design principle, a three-level response surface experiment was designed with the lateral inclination angles of M line segments as independent variables and separation efficiency as response value. Based on the separation efficiency test values ​​obtained by numerical simulation under Box-Beknhen Design, multiple regression fitting analysis was performed to establish a regression model. Perform variance analysis and significance test on the multiple regression model; Based on the synergistic effect of the M line segments when the lateral inclination angles are adjusted, the line segments and their combinations among the M line segments whose lateral inclination angles have the most significant effect on the separation efficiency are identified; The regression model is solved to determine the optimal lateral inclination angle of the local line segment to obtain the maximum separation efficiency.

2. A method for gradually optimizing the cross-sectional geometric parameters of a spiral chute according to claim 1, characterized in that: The threshold is 80% of the peak separation efficiency.

3. A method for gradually optimizing the cross-sectional geometric parameters of a spiral chute according to claim 1, characterized in that: The lateral inclination design value is adjusted based on a local line segment lateral inclination adjustment strategy, which uses a line segment between two end points to approximate a curve and adjusts based on the lateral inclination of M line segments as a reference or center.

4. A spiral chute test equipment, characterized in that: A method for gradually optimizing the cross-sectional geometric parameters of a spiral chute as described in any one of claims 1 to 3 is used to determine the geometric parameters of the optimal continuous curve cross-section and the optimal local line segment cross-section, and the geometric models of the two spiral chutes are drawn separately using SolidWorks software, and then the test equipment is manufactured by 3D printing.

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