A coal online sorting precision monitoring and analyzing system and method

Abstract

The present application provides a kind of coal online sorting precision monitoring analysis system and method, by adding different particle size magnetic ball in cyclone sorting, the product after sorting is recycled to determine the mixing amount of different magnetic ball in clean coal and gangue, the real-time product yield is obtained by weighing, the improved suspended distribution model is used to predict the distribution curve of product online, the precision of coal sorting is reflected in real time, the sorting process is optimized, and the precision and efficiency of coal sorting are improved.Simultaneously, it can also significantly improve the automation level of enterprise coal washing process, reduce labor cost and operating cost, so as to bring significant economic benefits for enterprise.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coal separation, and particularly relates to a coal online separation precision monitoring and analyzing system and method. BACKGROUND

[0002] Coal, as an important energy resource, its separation process plays a key role in the product quality and economic benefits of coal. Different separation systems and separation processes have different separation effects on coal, resulting in different clean coal yields. Therefore, in order to improve the clean coal yield, the separation effects of different separation processes need to be evaluated.

[0003] At the same time, the traditional coal separation process mainly relies on manual operation, which often leads to unstable quality and yield of the separated clean coal product. Therefore, the coal separation effect needs to be monitored in real time.

[0004] However, the evaluation and monitoring of the coal separation effect at present mainly rely on experience judgment, which is affected by personal subjective factors, and the accuracy of the judgment result is low. SUMMARY

[0005] In order to solve the above problems of the prior art, the present application provides a coal online separation precision monitoring and analyzing system and method, which can monitor the precision of coal separation in real time, timely feedback production parameters, optimize separation process, and improve the precision and efficiency of coal separation.

[0006] The present application is realized by the following technical solutions:

[0007] The present application provides a coal online separation precision monitoring and analyzing system, which comprises:

[0008] A cyclone is used for separating raw coal and magnetic small balls; the magnetic small balls are small balls with different densities and different particle sizes, and the same particle size corresponds to the same density;

[0009] An arc screen is used for de-meshing the overflow of the cyclone;

[0010] A first linear vibrating screen is used for de-meshing the oversize of the arc screen;

[0011] A first magnetic separation assembly is used for magnetically separating the oversize of the first linear vibrating screen, and separating out low-density magnetic small balls;

[0012] A clean coal bin is used for collecting the clean coal separated out by the first magnetic separation assembly;

[0013] A second linear vibrating screen is used for de-meshing the underflow of the cyclone;

[0014] A second magnetic separation assembly is used for magnetically separating the oversize of the second linear vibrating screen, and separating out high-density magnetic small balls;

[0015] The gangue bin is used to collect the gangue separated by the second magnetic separation component;

[0016] A stacked sieve is used to classify and sieve the low-density magnetic spheres and high-density magnetic spheres separated by the first magnetic separation component and the second magnetic separation component, respectively.

[0017] Weighing equipment is used to weigh low-density magnetic spheres and high-density magnetic spheres of various particle sizes separated by a stacked screen.

[0018] The controller is used to predict the distribution curve of clean coal based on the mass of low-density and high-density magnetic spheres of each particle size.

[0019] Preferably, the first magnetic separation component includes a first magnetic separator and a clean coal conveyor belt, with the first magnetic separator located above the clean coal conveyor belt; the oversize material of the first linear vibrating screen is transported to the clean coal bin via the clean coal conveyor belt, and during the transport process, the magnetic balls in the oversize material of the first linear vibrating screen are recovered to the first magnetic separator.

[0020] Preferably, the second magnetic separation component includes a second magnetic separator and a gangue conveyor belt, with the second magnetic separator located above the gangue conveyor belt; the oversize material of the second linear vibrating screen is transported to the gangue bin via the gangue conveyor belt, and during the transport process, the magnetic balls in the oversize material of the second linear vibrating screen are recovered to the second magnetic separator.

[0021] Preferably, it also includes a media collection tank, which is used to collect the heavy media that have exited from the arc screen, the first linear vibrating screen, and the second linear vibrating screen.

[0022] Furthermore, it also includes a slurry pump, through which the heavy medium in the combined medium tank is returned to the hydrocyclone.

[0023] Preferably, it also includes several magnetic ball barrels, each used to receive magnetic balls of different densities separated by the stacked sieve.

[0024] Preferably, the arc screen is a YHS type overflow arc screen.

[0025] Preferably, the stacked screen is a pull-out stacked screen.

[0026] This invention also provides a method for monitoring and analyzing the accuracy of online coal sorting, based on the aforementioned online coal sorting accuracy monitoring and analysis system, comprising:

[0027] Heavy medium, raw coal, and magnetic spheres are mixed and added to a hydrocyclone for separation to obtain overflow and underflow; the magnetic spheres are spheres of different densities and particle sizes, with the same particle size corresponding to the same density;

[0028] The overflow carrying some magnetic balls is dewatered and demediumed once through an arc screen. The material on the arc screen is fed into a first linear vibrating screen for secondary dewatering and demediuming. The material on the first linear vibrating screen is then fed into a first magnetic separation component to recover the magnetic balls. The remaining clean coal after recovery is fed into a clean coal bin. The recovered low-density magnetic balls are fed into a stacked screen for grading and screening. The low-density magnetic balls of each particle size are weighed to obtain the mass of the low-density magnetic balls of each particle size.

[0029] The underflow carries another portion of magnetic balls through the second linear vibrating screen for dewatering and demediuming. The material on the second linear vibrating screen is then processed by the second magnetic separation component to recover the magnetic balls. The remaining gangue after recovery enters the gangue bin. The recovered high-density magnetic balls are fed into a stacked screen for grading and screening. The high-density magnetic balls of each particle size are weighed to obtain the mass of each particle size.

[0030] The distribution curve of clean coal is predicted based on the mass of low-density magnetic spheres and high-density magnetic spheres of each particle size.

[0031] Preferably, the step of predicting the distribution curve of clean coal based on the mass of low-density magnetic spheres and high-density magnetic spheres of each particle size class specifically involves: using the mass of low-density magnetic spheres of each particle size class and the total mass of low-density magnetic spheres to determine the proportion of low-density magnetic spheres of each particle size class in the total low-density magnetic spheres; using the mass of high-density magnetic spheres of each particle size class and the total mass of high-density magnetic spheres to determine the proportion of high-density magnetic spheres of each particle size class in the total high-density magnetic spheres; calculating the distribution rate corresponding to each particle size class based on the obtained proportions, and plotting the distribution curve to determine the sorting accuracy.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] This invention introduces magnetic microspheres of different particle sizes into the hydrocyclone separation process. The magnetic microspheres are then recovered from the separated product, and the amount of each microsphere mixed in with clean coal and gangue is measured. The product yield is obtained through weighing. An improved suspension distribution model is used to predict the product distribution curve online, reflecting the accuracy of coal separation in real time, optimizing the separation process, and improving the precision and efficiency of coal separation. Simultaneously, it can significantly improve the automation level of the coal washing process, reduce labor and operating costs, and thus bring significant economic benefits to enterprises.

[0034] Furthermore, the present invention includes a media collection tank for collecting the heavy media removed from the arc screen, the first linear vibrating screen, and the second linear vibrating screen, so as to recycle the heavy media and improve the utilization rate. Attached Figure Description

[0035] 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.

[0036] Figure 1 This is a structural diagram of the device of the present invention.

[0037] In the diagram: 1. Hydrocyclone; 2. Arc screen; 3. First linear vibrating screen; 4. Second linear vibrating screen; 5. First magnetic separator; 6. Second magnetic separator; 7. Clean coal conveyor belt; 8. Gangue conveyor belt; 9. Stacked screen; 10. Mixing tank; 11. First magnetic ball tank; 12. Second magnetic ball tank; 13. Gangue bin; 14. Clean coal bin; 15. Slurry pump. Detailed Implementation

[0038] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0039] It should be noted that the process equipment or apparatus not specifically mentioned in the following embodiments are all conventional equipment or apparatus in the art.

[0040] It should be noted that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses. Furthermore, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not intended to limit the order of the method steps or define the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0041] Furthermore, it should be noted that the terms "first," "second," etc., used in this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. The terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements.

[0042] The online coal sorting accuracy monitoring and analysis system of the present invention includes:

[0043] Hydrocyclone 1 is used to separate raw coal and magnetic spheres; the magnetic spheres are spheres of different densities and particle sizes, with the same particle size corresponding to the same density;

[0044] Arc-shaped screen 2 is used to remove media from the overflow of hydrocyclone 1;

[0045] The first linear vibrating screen 3 is used to remove the medium from the material on the screen of the arc screen 2;

[0046] The first magnetic separation component is used to perform magnetic separation on the material on the first linear vibrating screen 3 to separate low-density magnetic balls.

[0047] The clean coal bin 14 is used to collect the clean coal separated by the first magnetic separation component;

[0048] The second linear vibrating screen 4 is used to remove the medium from the underflow of the hydrocyclone 1;

[0049] The second magnetic separation component is used to perform magnetic separation on the material on the second linear vibrating screen 4, separating out high-density magnetic balls;

[0050] Gangue bin 13 is used to collect gangue separated by the second magnetic separation component;

[0051] The stacked sieve 9 is used to classify and sieve the low-density magnetic spheres and high-density magnetic spheres separated by the first magnetic separation component and the second magnetic separation component, respectively.

[0052] Weighing equipment is used to weigh low-density magnetic spheres and high-density magnetic spheres of various particle sizes separated by the stacked sieve 9.

[0053] The controller is used to predict the distribution curve of clean coal based on the mass of low-density and high-density magnetic spheres of each particle size.

[0054] Specifically, in some embodiments, the first magnetic separation assembly includes a first magnetic separator 5 and a clean coal conveyor belt 7, with the first magnetic separator 5 located above the clean coal conveyor belt 7. The oversize material from the first linear vibrating screen 3 is conveyed to the clean coal bin 14 via the clean coal conveyor belt 7, and during the conveying process, the magnetic balls in the oversize material from the first linear vibrating screen 3 are recovered to the first magnetic separator 5. The second magnetic separation assembly includes a second magnetic separator 6 and a gangue conveyor belt 8, with the second magnetic separator 6 located above the gangue conveyor belt 8. The oversize material from the second linear vibrating screen 4 is conveyed to the gangue bin 13 via the gangue conveyor belt 8, and during the conveying process, the magnetic balls in the oversize material from the second linear vibrating screen 4 are recovered to the second magnetic separator 6. The function of each magnetic separation assembly in this invention is to separate magnetic balls. Other forms of magnetic separation assemblies can be used instead, as long as the separation and recovery of magnetic balls can be achieved.

[0055] To recover heavy media, this invention also includes a media collection tank 10, which collects the heavy media exiting from the arc screen 2, the first linear vibrating screen 3, and the second linear vibrating screen 4. The recovered heavy media can be returned to the hydrocyclone 1 for recycling. Specifically, a slurry pump 15 can be used to return the recovered heavy media to the hydrocyclone 1.

[0056] In a specific embodiment of the present invention, the arc screen 4 is selected as a YHS type overflow arc screen, for example, model YHS-1, with a screen inclination angle of 45° and a screen gap width of 0.1 mm.

[0057] In one specific embodiment of the present invention, the linear vibrating screen is model DZSF-520, and the screen aperture size is 0.074 mm.

[0058] In one specific embodiment of the present invention, the stacked screen 9 is a pull-out stacked screen, which allows for screen replacement.

[0059] The online coal sorting accuracy monitoring and analysis method of the present invention includes:

[0060] Heavy medium, raw coal and magnetic spheres are mixed and added to hydrocyclone 1 for separation to obtain overflow and underflow; the magnetic spheres are spheres of different densities and particle sizes, with the same particle size corresponding to the same density.

[0061] The overflow carrying some magnetic balls undergoes primary dewatering and demediuming through the arc screen 2. The material on the arc screen 2 is fed into the first linear vibrating screen 3 for secondary dewatering and demediuming. The material on the first linear vibrating screen 3 passes through the first magnetic separation component to recover the magnetic balls. The remaining clean coal after recovery enters the clean coal bin 14. The recovered low-density magnetic balls are fed into the stacked screen 9 for grading and screening. The low-density magnetic balls of each particle size are weighed to obtain the mass of the low-density magnetic balls of each particle size.

[0062] The underflow carries another portion of magnetic balls through the second linear vibrating screen 4 for dewatering and demediuming. The material on the screen of the second linear vibrating screen 4 is recycled by the second magnetic separation component. The remaining gangue after recycling enters the gangue bin 13. The high-density magnetic balls obtained are fed into the stacked screen 9 for grading and screening. The high-density magnetic balls of each particle size are weighed to obtain the mass of the high-density magnetic balls of each particle size.

[0063] The distribution curve of clean coal is predicted based on the mass of low-density magnetic spheres and high-density magnetic spheres of each particle size.

[0064] The magnetic microspheres described in this invention are microspheres of different densities and particle sizes, with the same particle size corresponding to the same density.

[0065] In one specific embodiment of the present invention, the density of the magnetic microspheres includes the following: 1.25 kg / cm³ 3 1.30kg / cm 3 1.34 kg / cm 3 1.37 kg / cm 3 1.40 kg / cm 3 1.45 kg / cm 3 1.50 kg / cm 3 1.70 kg / cm 3 1.80 kg / cm 3 1.90 kg / cm 3 The density corresponds to particle sizes of 55 mm, 50 mm, 45 mm, 40 mm, 35 mm, 30 mm, 25 mm, 20 mm, 15 mm, and 10 mm, respectively.

[0066] The particle size and density of the magnetic balls described in this invention can be changed according to the actual particle size and density composition of raw coal in order to better reflect the product sorting effect in actual production.

[0067] The method of predicting the distribution curve of clean coal based on the mass of low-density magnetic spheres and high-density magnetic spheres of each particle size is as follows: using the mass of low-density magnetic spheres of each particle size and the total mass of low-density magnetic spheres, the proportion of low-density magnetic spheres of each particle size in the total low-density magnetic spheres is calculated; using the mass of high-density magnetic spheres of each particle size and the total mass of high-density magnetic spheres, the proportion of high-density magnetic spheres of each particle size in the total high-density magnetic spheres is calculated; based on the obtained proportions, the distribution rate corresponding to each particle size is calculated, and the distribution curve is plotted to determine the sorting accuracy.

[0068] Example

[0069] In this embodiment, the online coal sorting accuracy monitoring and analysis system includes: a hydrocyclone 1, an arc screen 2, a first linear vibrating screen 3, a second linear vibrating screen 4, a first magnetic separator 5, a second magnetic separator 6, a clean coal conveyor belt 7, a gangue conveyor belt 8, a stacked screen 9, a mixing tank 10, a gangue bin 13, a clean coal bin 14, a slurry pump 15, and multiple magnetic ball bins. Figure 1 Only two magnetic sphere barrels are shown: the first magnetic sphere barrel 11 and the second magnetic sphere barrel 12; other magnetic sphere barrels are not shown. The hydrocyclone 1 is a heavy medium hydrocyclone.

[0070] Based on the aforementioned online coal sorting accuracy monitoring and analysis system, the method for monitoring and analyzing the accuracy of online coal sorting includes the following steps:

[0071] When raw coal and heavy media are mixed in a mixing tank, magnetic balls are added and mixed together to form a slurry. This slurry is then added to hydrocyclone 1 for separation. At this point, the density in hydrocyclone 1 is 1.40 g / cm³. 3 After sorting, overflow and underflow are obtained. The densities of the magnetic spheres include the following: 1.25 kg / cm³. 3 1.30 kg / cm 3 1.34 kg / cm 3 1.37 kg / cm 3 1.40 kg / cm 3 1.45 kg / cm 3 1.50 kg / cm 3 1.70 kg / cm 3 1.80 kg / cm 3 1.90 kg / cm 3 The density corresponds to particle sizes of 55 mm, 50 mm, 45 mm, 40 mm, 35 mm, 30 mm, 25 mm, 20 mm, 15 mm, and 10 mm, respectively.

[0072] The overflow of hydrocyclone 1 is a low-density product, which is fed into an arc screen 2 with an inclination angle of 45° and a diameter of 0.1 mm for primary dewatering and demediuming. In order to further remove the heavy medium from the product, the oversize of the arc screen 2 is fed into a first linear vibrating screen 3 with a diameter of 0.074 mm for secondary dewatering and demediuming. The undersize of the arc screen 2 and the undersize of the first linear vibrating screen 3 are heavy mediums, which are recycled into the combined medium tank 10. The oversize of the first linear vibrating screen 3 is fed into a clean coal conveyor belt 7 with a first magnetic separator 5 above it to recover magnetic balls. The remaining clean coal is transported to the clean coal bin 14 by the clean coal conveyor belt 7. The magnetic balls recovered by the first magnetic separator 5 are graded and screened by a stacked screen 9 with screen openings of 55 mm, 50 mm, 45 mm, 40 mm, 35 mm, 30 mm, 25 mm, 20 mm, 15 mm and 10 mm respectively. The low-density magnetic balls are separated and weighed.

[0073] The underflow of hydrocyclone 1 is a high-density product. Due to the high density, the arc screen will wear out severely. Therefore, it is dewatered and demediumed only by passing through a second linear vibrating screen with a diameter of 0.074 mm. The underflow from the second linear vibrating screen 4 enters the media collection tank 10 for recycling. The overflow from the second linear vibrating screen 4 passes through a gangue belt 8 with a second magnetic separator 6 above to recover magnetic balls. The remaining gangue enters the gangue bin 13. The magnetic balls recovered by the second magnetic separator 6 are graded and screened by a stacked screen 9 with screen openings of 55 mm, 50 mm, 45 mm, 40 mm, 35 mm, 30 mm, 25 mm, 20 mm, 15 mm, and 10 mm. After high-density magnetic balls are separated, they are weighed.

[0074] The heavy medium in the combined medium tank 10 is pumped into the hydrocyclone 1 by the slurry pump 15 for recycling.

[0075] After measuring the mass of low-density magnetic spheres and high-density magnetic spheres of each particle size, the proportion of low-density magnetic spheres of each particle size in the total low-density magnetic spheres is calculated using the mass of low-density magnetic spheres of each particle size and the total mass of low-density magnetic spheres. Similarly, the proportion of high-density magnetic spheres of each particle size in the total high-density magnetic spheres is calculated using the mass of high-density magnetic spheres of each particle size and the total mass of high-density magnetic spheres. Based on the obtained proportions, the distribution rate corresponding to each particle size is calculated, and a distribution curve is plotted to determine the sorting accuracy.

[0076] Furthermore, based on the mass of low-density and high-density magnetic spheres of various particle sizes, the distribution curve of clean coal can be predicted using a suitable suspension distribution model (RSM-VOF model or RSM-Mixture model), thereby providing methodological support for determining the optimal separation density corresponding to a given ash product.

[0077] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A coal on-line sorting precision monitoring and analyzing system, characterized in that, The application relates to a coal separation device. The device comprises a cyclone (1) for separating raw coal and magnetic small balls; the magnetic small balls are small balls with different densities and different particle sizes, and the same particle size corresponds to the same density; an arc screen (2) for removing medium from overflow of the cyclone (1); a first linear vibration screen (3) for removing medium from screen oversize of the arc screen (2); a first magnetic separation assembly for magnetically separating screen oversize of the first linear vibration screen (3) to separate low-density magnetic small balls; a clean coal bin (14) for collecting clean coal separated by the first magnetic separation assembly; a second linear vibration screen (4) for removing medium from underflow of the cyclone (1); a second magnetic separation assembly for magnetically separating screen oversize of the second linear vibration screen (4) to separate high-density magnetic small balls; a gangue bin (13) for collecting gangue separated by the second magnetic separation assembly; a laminated screen (9) for grading and screening low-density magnetic small balls and high-density magnetic small balls separated by the first magnetic separation assembly and the second magnetic separation assembly; a weighing device for weighing low-density magnetic small balls and high-density magnetic small balls of each particle size separated by the laminated screen (9); and a controller for predicting a distribution curve of clean coal according to the mass of low-density magnetic small balls and high-density magnetic small balls of each particle size, wherein the mass of low-density magnetic small balls of each particle size and the mass of total low-density magnetic small balls are used to obtain the proportion of low-density magnetic small balls of each particle size in total low-density magnetic small balls, the mass of high-density magnetic small balls of each particle size and the mass of total high-density magnetic small balls are used to obtain the proportion of high-density magnetic small balls of each particle size in total high-density magnetic small balls, and the distribution rate corresponding to each particle size is calculated according to the obtained proportions to draw the distribution curve and determine the separation precision. The first magnetic separation assembly comprises a first magnetic separator (5) and a clean coal belt (7), the first magnetic separator (5) is located above the clean coal belt (7), screen oversize of the first linear vibration screen is conveyed to the clean coal bin (14) through the clean coal belt (7), and magnetic small balls in the screen oversize of the first linear vibration screen are recycled to the first magnetic separator (5) in the conveying process. The second magnetic separation assembly comprises a second magnetic separator (6) and a gangue belt (8), the second magnetic separator (6) is located above the gangue belt (8), screen oversize of the second linear vibration screen is conveyed to the gangue bin (13) through the gangue belt (8), and magnetic small balls in the screen oversize of the second linear vibration screen are recycled to the second magnetic separator (6) in the conveying process. The device further comprises a medium collecting barrel (10) for collecting heavy medium removed by the arc screen (2), the first linear vibration screen (3) and the second linear vibration screen (4). The device further comprises a slurry pump (15), and the heavy medium in the medium collecting barrel (10) is returned to the cyclone (1) through the slurry pump (15). The device further comprises a plurality of magnetic small ball barrels for receiving magnetic small balls with different densities separated by the laminated screen (9). The arc screen is a YHS overflow type arc screen. The laminated screen (9) is a pull-out type laminated screen. ​ ​ ​ 2. The coal on-line sorting precision monitoring and analyzing system according to claim 1, characterized in that, ​ 3. The coal on-line sorting precision monitoring and analyzing system according to claim 1, characterized in that, ​ 4. The coal on-line sorting precision monitoring and analyzing system according to claim 1, characterized in that, ​ 5. The coal on-line sorting precision monitoring and analyzing system according to claim 4, characterized in that, ​ 6. The coal on-line sorting precision monitoring and analyzing system according to claim 1, characterized in that, ​ 7. The coal on-line sorting precision monitoring and analyzing system according to claim 1, characterized in that, ​ 8. The coal on-line sorting precision monitoring and analyzing system according to claim 1, characterized in that, ​ 9. A coal on-line sorting precision monitoring and analyzing method, characterized in that, The coal online sorting precision monitoring and analyzing system based on any one of claims 1-8 comprises: The heavy medium, raw coal and magnetic small balls are mixed and added into the cyclone (1) for sorting to obtain overflow and underflow; the magnetic small balls are small balls with different densities and different particle sizes, and the same particle size corresponds to the same density; The overflow carrying part of the magnetic small balls is subjected to primary dewatering and medium removal through the arc screen (2), and the oversize of the arc screen (2) is fed into the first linear vibration screen (3) for secondary dewatering and medium removal; the oversize of the first linear vibration screen (3) is subjected to recovery of the magnetic small balls through the first magnetic separation assembly, and the remaining clean coal after recovery is fed into the clean coal bin (14); the low-density magnetic small balls recovered are fed into the laminated screen (9) for grading screening, and each particle size level of the low-density magnetic small balls screened is weighed to obtain the mass of each particle size level of the low-density magnetic small balls; The underflow carrying another part of the magnetic small balls is subjected to dewatering and medium removal through the second linear vibration screen (4), and the oversize of the second linear vibration screen (4) is subjected to recovery of the magnetic small balls through the second magnetic separation assembly, and the remaining gangue after recovery is fed into the gangue bin (13), and the high-density magnetic small balls recovered are fed into the laminated screen (9) for grading screening, and each particle size level of the high-density magnetic small balls screened is weighed to obtain the mass of each particle size level of the high-density magnetic small balls; The distribution curve of the clean coal is predicted according to the mass of each particle size level of the low-density magnetic small balls and the high-density magnetic small balls.

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