System for enriching clay minerals from coal slime and operation method thereof

Abstract

The invention belongs to the technical field of solid waste treatment, provides a system for enriching clay minerals from coal slime and an operation method of the system, and solves the problem of sedimentation of difficult-to-settle coal slime water and the problem that the coal slime is difficult to digest. The system comprises the following devices: a first-section cyclone 3, a second-section grading system, a third-section grading system, a parallel cyclone group 16, a tailing filter press 18, a clay thickener 19 and a clay filter press 20, the second-section grading system comprises a second-section cyclone jet aerator 6, a pipeline mixer 7, a flotation tank 8, a medium slime filter press 10 and a second-section cyclone 23; and the third-section grading system comprises a parallel cyclone group 13 and a series cyclone group 21. The method comprises the following steps: carrying out subsequent treatment on first overflow obtained from a first-section cyclone 3 to obtain medium slime; and finally, converging the final product, and feeding overflow into a clay filter press through a clay thickener to obtain clay minerals.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste treatment, and in particular to a system for enriching clay minerals from coal slime and an operation method thereof. Background Art

[0002] Clay minerals are important non-metallic mineral resources, and coal-associated clay minerals are my country's advantageous non-metallic mineral resources. They play an important role in the development of modern industries and the technological progress of traditional industries. The products have high added value and good economic benefits. For the recovery and utilization of kaolin in massive coal gangue, dry air separation, intelligent dry separation, gravity separation, heavy medium separation and other methods can be used. There have been many literature reports, and some have been industrialized. However, there are few processes for the recovery of clay minerals in coal slime.

[0003] As flotation technology becomes increasingly sophisticated, the ash content of flotation tailings of coal preparation plants has generally increased to more than 60%. This part of the coal slime can no longer be sold as a coal product, and direct discharge will greatly affect the ecological environment. The disposal problem of high-ash coal slime can be solved with the enrichment and comprehensive utilization of clay minerals. Therefore, solving the current status of coal slime stacking and disposal and realizing the resourceization of coal slime solid waste have become issues that need to be urgently addressed. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects in the prior art and provide a system for enriching clay minerals from coal slime and an operating method thereof.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a system for enriching clay minerals from coal slime, comprising the following devices: a first-stage cyclone 3, a second-stage classification system, a third-stage classification system, a parallel cyclone group 16, a tail coal filter press 18, a clay concentrator 19, and a clay filter press 20;

[0007] The second stage classification system includes a second stage cyclone jet aerator 6, a pipeline mixer 7, a flotation tank 8, a medium coal slime filter press 10, and a second stage cyclone 23;

[0008] The third stage classification system includes a parallel cyclone group 13 and a series cyclone group 21 .

[0009] Preferably, the single body diameter of the first stage cyclone 3 is 200-300 mm;

[0010] The single body diameter of the second stage swirl jet aerator 6 is 100-150 mm;

[0011] The single body diameter of the second stage cyclone 23 is 100-150 mm.

[0012] Preferably, the monomer quantity ratio of the first stage cyclone 3 to the second stage cyclone jet aerator 6 is 1:3-9;

[0013] The ratio of the number of monomers of the first stage cyclone 3 to the number of monomers of the second stage cyclone 23 is 1:3-9.

[0014] Preferably, the single body diameter of the parallel cyclone group 16 is 15 to 35 mm;

[0015] The diameter of each unit of the parallel cyclone group 13 is 50-75 mm; the diameter of each unit of the series cyclone group 21 is 50-75 mm.

[0016] Preferably, the ratio of the number of monomers of the first stage cyclone 3 and the parallel cyclone group 13 is 1:10-22;

[0017] The ratio of the number of monomers of the first-stage cyclone 3 to the number of monomers of the parallel cyclone group 16 is 1:50-190.

[0018] The present invention also provides an operating method of the system for enriching clay minerals from coal slime, comprising the following steps:

[0019] (1) feeding the coal slurry into the first stage cyclone 3 for classification to obtain a first underflow and a first overflow;

[0020] (2) The first overflow is fed into the second-stage cyclone jet aerator 6 to obtain a second underflow and a second overflow; the second overflow enters the flotation tank 8 through the pipeline mixer 7 for flotation to obtain a foam product and an underflow; the foam product is fed into the medium coal slime filter press 10 for filtration and dehydration to obtain medium coal slime; or;

[0021] The first overflow is fed into the second stage cyclone 23 to obtain a second underflow and a second overflow;

[0022] (3) the second overflow or the underflow of the flotation tank 8 is fed into the parallel cyclone group 13 to obtain a third underflow and a third overflow, and the third overflow is fed into the parallel cyclone group 16 to obtain a fourth underflow and a fourth overflow; or;

[0023] The second overflow or underflow of the flotation tank 8 is fed into the series cyclone group 21 to obtain overflow and underflow;

[0024] (4) The first underflow, the second underflow, the third underflow, the fourth underflow and the underflow generated by the series cyclone group 21 are fed into the tail coal filter press 18, and the tail coal is obtained by filtering and dehydrating;

[0025] (5) The fourth overflow or the overflow generated by the series cyclone group 21 is fed into the clay filter press 20 through the clay concentrator 19, and the clay minerals are obtained by filtration and dehydration.

[0026] The present invention provides a system for enriching clay minerals from coal slime, comprising the following devices: a first-stage cyclone 3, a second-stage classification system, a third-stage classification system, a parallel cyclone group 16, a tail coal filter press 18, a clay concentrator 19, and a clay filter press 20; the second-stage classification system comprises a second-stage cyclone jet aerator 6, a pipeline mixer 7, a flotation tank 8, a medium coal slime filter press 10, and a second-stage cyclone 23; the third-stage classification system comprises a parallel cyclone group 13 and a series cyclone group 21.

[0027] The present invention also provides an operation method of the system, which performs subsequent processing on the first overflow obtained from the first-stage cyclone 3, and obtains medium coal slime, underflow or second overflow according to different raw materials or equipment selected in the next step; then, according to the selection of the parallel cyclone group 13 or the series cyclone group 21 in the next step, different processing methods are operated to finally obtain the fourth underflow, the fourth overflow, the overflow and the underflow generated by the series cyclone group 21; finally, the final products are converged, the underflow enters the tail coal filter press 18 for filtration and dehydration to obtain tail coal, the overflow is concentrated by the clay concentrator 19 and then fed into the clay filter press 20, and clay minerals are obtained after filtration and dehydration.

[0028] The system for enriching clay minerals from coal slime provided by the present invention has a clear structure, is flexible and reliable, and can select different processes according to the on-site coal slime conditions and design objectives to obtain corresponding products, thereby completing the recovery of clay minerals and solving the sedimentation problem of difficult-to-sink coal slime water and the problem of coal slime being difficult to dispose of. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the process of enriching clay minerals from coal slime in Example 1;

[0030] Among them, 1 is the first feed barrel, 2 is the pump, 3 is the first stage cyclone, 4 is the second feed barrel, 5 is the pump, 6 is the second stage cyclone jet aerator, 7 is the pipeline mixer, 8 is the flotation tank, 9 is the middle coal barrel, 10 is the middle coal slime filter press, 11 is the third feed barrel, 12 is the pump, 13 is the parallel cyclone group, 14 is the fourth feed barrel, 15 is the pump, 16 is the parallel cyclone group, 17 is the tail coal barrel, 18 is the tail coal filter press, 19 is the clay concentrator, and 20 is the clay filter press;

[0031] Figure 2 This is a schematic diagram of the process of enriching clay minerals from coal slime in Example 2;

[0032] Among them, 1 is the first feed barrel, 2 is the pump, 3 is the first stage cyclone, 4 is the second feed barrel, 5 is the pump, 6 is the second stage cyclone jet aerator, 7 is the pipeline mixer, 8 is the flotation tank, 9 is the middle coal barrel, 10 is the middle coal slime filter press, 11 is the third feed barrel, 12 is the pump, 17 is the tail coal barrel, 18 is the tail coal filter press, 19 is the clay thickener, 20 is the clay filter press, and 21 is the series cyclone group;

[0033] Figure 3 This is a schematic diagram of the process of enriching clay minerals from coal slime in Example 3;

[0034] Among them, 1 is the first feed barrel, 2 is the pump, 3 is the first stage cyclone, 4 is the second feed barrel, 5 is the pump, 23 is the second stage cyclone, 11 is the third feed barrel, 12 is the pump, 13 is the parallel cyclone group, 14 is the fourth feed barrel, 15 is the pump, 16 is the parallel cyclone group, 17 is the tail coal barrel, 18 is the tail coal filter press, 19 is the clay concentrator, 20 is the clay filter press, and 22 is the clay concentrator tank;

[0035] Figure 4 is a scanning electron microscope image of the clay mineral in Example 1;

[0036] Figure 5 is a scanning electron microscope image of the clay mineral in Example 2;

[0037] Figure 6 This is a scanning electron microscope image of the clay mineral in Example 3. DETAILED DESCRIPTION

[0038] The present invention provides a system for enriching clay minerals from coal slime, comprising the following devices: a first-stage cyclone 3, a second-stage classification system, a third-stage classification system, a parallel cyclone group 16, a tail coal filter press 18, a clay concentrator 19, and a clay filter press 20;

[0039] The second stage classification system includes a second stage cyclone jet aerator 6, a pipeline mixer 7, a flotation tank 8, a medium coal slime filter press 10, and a second stage cyclone 23;

[0040] The third stage classification system includes a parallel cyclone group 13 and a series cyclone group 21 .

[0041] In the present invention, the system for enriching clay minerals from coal slime also includes the following devices: a first feed barrel 1, a pump 2, a second feed barrel 4, a pump 5, a middle coal barrel 9, a third feed barrel 11, a pump 12, a fourth feed barrel 14, a pump 15, a tail coal barrel 17, and a clay concentration tank 22.

[0042] In the present invention, the single body diameter of the first stage cyclone 3 is preferably 200-300 mm, more preferably 200-275 mm, and even more preferably 200-250 mm.

[0043] In the present invention, the single body diameter of the second stage swirl jet aerator 6 is preferably 100 to 150 mm, more preferably 100 to 138 mm, and even more preferably 100 to 125 mm.

[0044] In the present invention, the single body diameter of the second stage cyclone 23 is preferably 100 to 150 mm, more preferably 100 to 138 mm, and even more preferably 100 to 125 mm.

[0045] In the present invention, the monomer quantity ratio of the first stage cyclone 3 and the second stage cyclone jet aerator 6 is preferably 1:3-9, more preferably 1:4-8, and even more preferably 1:4-6.

[0046] In the present invention, the ratio of the number of monomers of the first stage cyclone 3 to the number of monomers of the second stage cyclone 23 is preferably 1:3-9, more preferably 1:4-8, and even more preferably 1:4-6.

[0047] In the present invention, the single body diameter of the parallel cyclone group 16 is preferably 15 to 35 mm, more preferably 15 to 30 mm, and even more preferably 15 to 25 mm.

[0048] In the present invention, the monomer diameter of the parallel cyclone group 13 is preferably 50-75 mm, more preferably 50-70 mm, and more preferably 50-60 mm; the monomer diameter of the series cyclone group 21 is preferably 50-75 mm, more preferably 50-70 mm, and more preferably 50-60 mm.

[0049] In the present invention, the overflow port diameter of the monomers of the series cyclone group 21 decreases, and the decrease range is preferably 20-25%, further preferably 21-24%, and more preferably 22-24%; the feed port diameter of the monomers of the series cyclone group 21 decreases, and the decrease range is preferably 20-25%, further preferably 21-24%, and more preferably 22-24%.

[0050] In the present invention, the ratio of the number of monomers of the first stage cyclone 3 to the number of monomers of the parallel cyclone group 13 is preferably 1:10-22, more preferably 1:12-16, and even more preferably 1:13-15.

[0051] In the present invention, the ratio of the number of monomers of the first stage cyclone 3 to the number of monomers of the parallel cyclone group 16 is preferably 1:50-190, more preferably 1:80-150, and even more preferably 1:100-144.

[0052] In the present invention, the number ratio of the first-stage cyclone 3 monomers to the series cyclone group 21 is preferably 1:10-22, more preferably 1:12-16, and even more preferably 1:13-15.

[0053] The present invention also provides an operating method of the system for enriching clay minerals from coal slime, comprising the following steps:

[0054] In the present invention, the coal sludge water of the coal preparation plant first enters the first feed bucket 1, and then is fed into the first cyclone 3 through the pump 2 for classification to obtain the first underflow and the first overflow; the first overflow is collected in the second feed bucket 4 and fed into the next device through the pump 5.

[0055] In the present invention, the first overflow has different treatment methods and can be fed into the second-stage swirl jet aerator 6 or the second-stage cyclone 23 .

[0056] In the present invention, after the first overflow is fed into the second-stage cyclone jet aerator 6, it is graded to obtain a second underflow and a second overflow; after the second overflow is aerated, it enters the flotation tank 8 through the pipeline mixer 7 for flotation decarbonization to obtain a foam product and an underflow; the foam product is collected in a medium coal barrel 9, and then fed into a medium coal slime filter press 10 for dehydration to obtain medium coal slime.

[0057] In the present invention, a collector and a frother are added to the flotation tank 8 or the overflow pipe of the second-stage cyclone jet aerator 6, so that the flotation tank 8 performs flotation decarbonization.

[0058] In the present invention, the frothing method of the flotation cell 8 is the self-priming or aeration frothing of a conventional mechanical stirring flotation machine, or the frothing of a flotation column ejector or a microbubble generator.

[0059] In the present invention, when the first overflow is fed into the second stage cyclone 23 for classification, a second underflow and a second overflow are obtained.

[0060] In the present invention, the underflow generated by the second overflow or flotation tank 8 is collected in the third feed bucket 11 and processed in different ways, and can be fed into the parallel cyclone group 13 or the series cyclone group 21 .

[0061] In the present invention, when the second overflow or the underflow of the flotation tank 8 is collected in the third feed bucket 11, it is fed into the parallel cyclone group 13 for classification through the pump 12 to obtain the third underflow and the third overflow. The third overflow is collected in the fourth feed bucket 14, fed into the parallel cyclone group 16 through the pump 15, and classified to obtain the fourth underflow and the fourth overflow.

[0062] In the present invention, after the second overflow or the underflow of the flotation tank 8 collected in the third feed bucket 11 is fed into the series cyclone group 21 through the pump 12, the overflow and the underflow are obtained by classification.

[0063] In the present invention, the first underflow, the second underflow, the third underflow, the fourth underflow and the underflow generated by the series cyclone group 21 are collected in the tail coal bucket 17, and then fed into the tail coal filter press 18 to obtain tail coal after dehydration.

[0064] In the present invention, the overflow generated by the fourth overflow or the series cyclone group 21 is collected and concentrated by the clay concentrator 19, and then fed into the clay filter press 20 for dehydration to obtain clay minerals.

[0065] In the present invention, the overflow after being processed by the clay concentrator 19 can be fed into the clay concentration tank 22 for a second concentration to obtain a slurry that meets the feed concentration requirement of the filter press.

[0066] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0067] Example 1

[0068] In this embodiment, the monomer diameter of the first-stage cyclone 3 is 200 mm, the monomer diameter of the second-stage cyclone jet aerator 6 is 100 mm, and the monomer quantity ratio of the first-stage cyclone 3 and the second-stage cyclone jet aerator 6 is 1:4; the monomer diameter of the parallel cyclone 16 is 25 mm, the monomer diameter of the parallel cyclone group 13 is 50 mm, and the monomer quantity ratio of the first-stage cyclone 3 and the parallel cyclone group 13 is 1:16; the monomer quantity ratio of the first-stage cyclone 3 and the parallel cyclone group 16 is 1:100.

[0069] The coal slime first enters the first feed barrel 1, and is fed into the first-stage cyclone 3 by a pump 2 for classification to obtain a first underflow and a first overflow; the first overflow enters the second feed barrel 4, and is fed into the second-stage cyclone jet aerator 6 by a pump 5 for second-stage classification to obtain a second underflow and a second overflow; the second overflow is aerated and enters the flotation tank 8 through the pipeline mixer 7, and under the action of the collector, the medium coal particles adhere to the bubbles and float to become a foam product, which is fed into the medium coal slime filter press 10 through the medium coal barrel 9 for dehydration to obtain the medium coal slime;

[0070] The underflow of the flotation tank 8 enters the third feed bucket 11, and is fed into the parallel cyclone group 13 by a pump 12, and is classified to obtain a third underflow and a third overflow. The third overflow passes through the fourth feed bucket 14, and is fed into the parallel cyclone group 16 by a pump 15 to obtain a fourth underflow and a fourth overflow. The fourth overflow is concentrated by a clay concentrator 19 and dehydrated by a clay filter press 20 to become a clay mineral.

[0071] The first underflow, the second underflow, the third underflow and the fourth underflow are combined and enter the tail coal bucket 17, and then pass through the tail coal filter press 18 to dehydrate and become the tail coal product.

[0072] The schematic diagram of the process of enriching clay minerals from coal slime in this embodiment is as follows: Figure 1 shown.

[0073] Example 2

[0074] In this embodiment, the monomer diameter of the first-stage cyclone 3 is 200 mm, the monomer diameter of the second-stage cyclone jet aerator 6 is 100 mm, and the monomer quantity ratio of the first-stage cyclone 3 and the second-stage cyclone jet aerator 6 is 1:4; the monomer diameter of the series cyclone group 21 is 50 mm, the overflow port of the monomer of the series cyclone group 2 decreases at a rate of 20%, and the feed port decreases at a rate of 20%; the number ratio of the monomer of the first-stage cyclone 3 to the series cyclone group 21 is 1:16.

[0075] The coal slime first enters the first feed barrel 1, and is fed into the first-stage cyclone 3 by a pump 2 for classification to obtain a first underflow and a first overflow; the first overflow enters the second feed barrel 4, and is fed into the second-stage cyclone jet aerator 6 by a pump 5 for second-stage classification to obtain a second underflow and a second overflow; the second overflow is aerated and enters the flotation tank 8 through the pipeline mixer 7, and under the action of the collector, the medium coal particles adhere to the bubbles and float to become a foam product, which is fed into the medium coal slime filter press 10 through the medium coal barrel 9 for dehydration to obtain the medium coal slime;

[0076] The underflow of the flotation tank 8 enters the third feed barrel 11 and is fed into the series cyclone group 21 by a pump 12 to obtain overflow and underflow. The overflow is concentrated by a clay concentrator 19 and dehydrated by a clay filter press 20 to become clay minerals.

[0077] The underflow of the series cyclone group 21 is combined with the first underflow and the second underflow to enter the tail coal bucket 17, and then passes through the tail coal filter press 18 to be dehydrated to become the tail coal product.

[0078] The schematic diagram of the process of enriching clay minerals from coal slime in this embodiment is as follows: Figure 2 shown.

[0079] Example 3

[0080] In this embodiment, the monomer diameter of the first-stage cyclone 3 is 200 mm, the monomer diameter of the second-stage cyclone 23 is 100 mm, and the monomer quantity ratio of the first-stage cyclone 3 to the second-stage cyclone 23 is 1:4; the monomer diameter of the parallel cyclone 16 is 25 mm, the monomer diameter of the parallel cyclone group 13 is 50 mm, and the monomer quantity ratio of the first-stage cyclone 3 to the parallel cyclone group 13 is 1:16; the monomer quantity ratio of the first-stage cyclone 3 to the parallel cyclone group 16 is 1:100.

[0081] The coal slime of the coal preparation plant first enters the first feed barrel 1, and is fed into the first stage cyclone 3 by a pump 2 for classification to obtain the first underflow and the first overflow; the first overflow enters the second feed barrel 4, and is fed into the second stage cyclone 23 by a pump 5 for second stage classification to obtain the second underflow and the second overflow; the second overflow enters the third feed barrel 11, and is fed into the parallel cyclone group 13 by a pump 12 to obtain the third underflow and the third overflow; the third overflow passes through the fourth feed barrel 14, and is fed into the parallel cyclone group 16 by a pump 15 for the last classification to obtain the fourth underflow and the fourth overflow; the fourth overflow enters the clay concentrator 19 for the first concentration, and the underflow of the clay concentrator 19 enters the clay concentration tank 22 for re-concentration, and the underflow of the clay concentration tank 22 becomes clay minerals after being dehydrated by the clay filter press 20;

[0082] The first underflow, the second underflow, the third underflow, and the fourth underflow are combined and enter the tail coal bucket 17, and then pass through the tail coal filter press 18 to dehydrate and become the tail coal product. Figure 3 shown.

[0083] The products obtained in Examples 1 to 3 were tested and the results are recorded in Table 1.

[0084] Table 1 Test results

[0085]

[0086] The clay minerals obtained in Examples 1 to 3 were scanned by electron microscope. Figure 4 is a scanning electron microscope image of the clay mineral in Example 1; Figure 5 is a scanning electron microscope image of the clay mineral in Example 2; Figure 6 This is a scanning electron microscope image of the clay mineral in Example 3.

[0087] from Figures 4 to 6 It can be seen that the clay minerals obtained by using Examples 1 to 3 are mainly kaolinite minerals, and contain very small amounts of coal particles or quartz particles.

[0088] It can be seen from the above embodiments that the present invention performs subsequent processing on the first overflow obtained from the first stage cyclone, and obtains medium coal slime, underflow or second overflow according to different equipment selected in the next step, thereby obtaining different processing methods; then, according to the selection of the parallel cyclone group or the series cyclone group in the next step, different processing methods are obtained, and finally the fourth underflow, the fourth overflow, the overflow and the tail flow generated by the series cyclone group 21 are obtained; finally, the final products are converged, the underflow enters the tail coal filter press to obtain tail coal, and the overflow is fed into the clay filter press through the clay concentrator to obtain clay minerals.

[0089] The system for enriching clay minerals from coal slime provided by the present invention has a clear structure, is flexible and reliable, and can select different processes according to the coal slime conditions on site and the design objectives, thereby obtaining corresponding products and completing the recovery of clay minerals.

[0090] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A system for enriching clay minerals from coal slime, characterized in that: Contains the following equipment: A first-stage hydrocyclone (3), a second-stage classification system, a third-stage classification system, a parallel hydrocyclone group (16), a tail coal filter press (18), a clay concentrator (19), and a clay filter press (20); The second stage classification system comprises a second stage cyclone jet aerator (6), a pipeline mixer (7), a flotation tank (8), a medium coal slime filter press (10), and a second stage cyclone (23); The third stage classification system comprises a parallel cyclone group (13) and a series cyclone group (21).

2. The system for enriching clay minerals from coal slime according to claim 1, characterized in that: The single body diameter of the first stage cyclone (3) is 200-300 mm; The single body diameter of the second stage swirl jet aerator (6) is 100-150 mm; The single body diameter of the second stage cyclone (23) is 100-150 mm.

3. The system for enriching clay minerals from coal slime according to claim 1 or 2, characterized in that: The ratio of the number of monomers of the first-stage cyclone (3) and the second-stage cyclone jet aerator (6) is 1:3-9; The ratio of the number of monomers of the first-stage cyclone (3) to that of the second-stage cyclone (23) is 1:3-9.

4. The system for enriching clay minerals from coal slime according to claim 3, characterized in that: The single body diameter of the parallel cyclone group (16) is 15 to 35 mm; The diameter of a single unit of the parallel cyclone group (13) is 50 to 75 mm; the diameter of a single unit of the series cyclone group (21) is 50 to 75 mm.

5. The system for enriching clay minerals from coal slime according to claim 4, characterized in that: The ratio of the number of monomers of the first stage cyclone (3) to the number of monomers of the parallel cyclone group (13) is 1:10 to 22; The ratio of the number of monomers of the first-stage cyclone (3) and the parallel cyclone group (16) is 1:50-190.

6. The method for operating the system for enriching clay minerals from coal slime according to any one of claims 1 to 5, characterized in that: It includes the following steps: (1) feeding the coal slurry into the first stage cyclone (3) for classification to obtain a first underflow and a first overflow; (2) the first overflow is fed into the second-stage cyclone jet aerator (6) to obtain a second underflow and a second overflow; the second overflow enters the flotation tank (8) through the pipeline mixer (7) for flotation to obtain a foam product and an underflow; the foam product is fed into the medium coal slime filter press (10) for filtration and dehydration to obtain medium coal slime; or; The first overflow is fed into the second stage cyclone (23) to obtain a second underflow and a second overflow; (3) the second overflow or the underflow of the flotation tank (8) is fed into a parallel cyclone group (13) to obtain a third underflow and a third overflow, and the third overflow is fed into a parallel cyclone group (16) to obtain a fourth underflow and a fourth overflow; or; The second overflow or underflow of the flotation tank (8) is fed into a series of cyclone groups (21) to obtain overflow and underflow; (4) the first underflow, the second underflow, the third underflow, the fourth underflow and the underflow generated by the series cyclone group (21) are fed into a tail coal filter press (18) for filtering and dehydration to obtain tail coal; (5) The fourth overflow or the overflow generated by the series cyclone group (21) is fed into the clay filter press (20) through the clay concentrator (19), and is filtered and dehydrated to obtain clay minerals.

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