A dense medium pan and method of separation

Abstract

The present application belongs to the technical field of lump coal separation, and aims to solve the problem that the existing separator has poor separation effect on 13-6mm size coal, and needs to be equipped with a heavy medium system for fine coal. A heavy medium shallow tank cascade separator is provided, the raw material to be separated is divided into upper layer lump clean coal and part of fine coal which is not effectively separated, and bottom layer lump gangue in the heavy medium suspension in the main separation tank based on the Archimedes principle; the upper layer lump clean coal and fine coal are scraped to the grate by the obliquely arranged rotating scraper wheel, the grate aperture is 13mm, the fine coal passes through the sieve hole and falls into the lower re-separation tank, the lump clean coal slides downward along the inclined grate; the fine coal is stratified according to the density difference in the heavy medium suspension in the re-separation tank, the upper layer fine clean coal is discharged from the overflow port under the action of horizontal flow, and the bottom layer fine gangue slides along the inclined tank bottom to the lump gangue area of the main tank, and the lump gangue and fine gangue are discharged by the scraper. The present application can realize cascade heavy medium separation of 300-6mm size coal, and does not need to add a heavy medium separation system for fine coal.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of lump coal separation, and particularly relates to a heavy medium shallow tank cascade separator and a separation method. BACKGROUND

[0002] The heavy medium shallow tank separator is a high-efficiency lump coal separation device, and is currently mainly applied to the separation of lump coal in a power coal preparation plant and the pre-removal of gangue in a coking coal preparation plant. The heavy medium shallow tank separator is composed of a horizontal medium tank, an upward flow funnel, a tank body, a clean coal overflow weir, a driving mechanism, an upward flow pipeline and funnel, a horizontal flow pipeline, a gangue removal scraper, a chain sprocket, a deflector and a tensioning mechanism.

[0003] The working medium of the heavy medium shallow tank separator is a heavy medium suspension, which is a suspension formed by mixing a certain amount of magnet powder and water, and is introduced into the tank body as upward flow and horizontal flow through the upward flow funnel at the bottom and the horizontal medium tank. During operation, the heavy medium suspension is first allowed to run stably in the tank body; then, raw coal is allowed to fall into the tank body from above the horizontal flow, and is fully mixed with the heavy medium; the selected raw coal is uniformly and stably moved from the feed inlet to the separation zone under the action of the horizontal flow, and is dispersed to all parts of the tank body under the action of the upward flow, so that the separation flow field is kept stable and the medium does not precipitate; at this time, the raw coal in the tank body gradually floats to the overflow area according to the Archimedes principle, and is then discharged out of the tank by the action of the horizontal flow for further processing; the heavy product with a higher density gradually settles to the underflow area, and is then removed from the tank body by the gangue removal device; the heavy medium attached to the heavy product and the light product is recovered to the medium barrel through the medium removal screen, and is recycled after the magnet powder is recovered by the magnetic separator.

[0004] The existing heavy medium shallow tank separator only has a good separation effect on the 200-13mm particle size raw coal, and has a poor separation effect on the 13-6mm particle size. Usually, the 13-6mm particle size is separated by a fine coal heavy medium cyclone, and a set of fine coal heavy medium system needs to be configured, which leads to a complex process and a high production cost of the coal preparation plant. SUMMARY

[0005] The present application provides a heavy medium shallow tank cascade separator and a separation method to solve at least one of the above technical problems in the prior art.

[0006] The present application adopts the following technical solution: a heavy medium shallow tank cascade separator, comprising a machine body and a heavy medium feeding assembly, a main separation tank, a re-separation tank, a gangue removal assembly, a rotating paddle wheel and a grate strip arranged on the machine body.

[0007] The machine body is provided with a feeding tank for the raw material to be separated to enter the main separation tank.

[0008] The heavy medium feeding assembly is used to provide the heavy medium suspension into the main separation tank and the re-separation tank;

[0009] The raw material to be separated is separated into the upper layer of lump clean coal and slack coal and the bottom layer of lump gangue in the heavy medium suspension in the main separation tank based on the Archimedes principle;

[0010] The upper layer of lump clean coal and slack coal is scraped to the grate by the obliquely arranged rotating push wheel, the slack coal falls into the lower re-separation tank through the screen hole of the grate, and the lump clean coal slides downward along the inclined grate; the separated slack coal is further layered based on the Archimedes principle according to the density difference in the heavy medium suspension in the re-separation tank, the upper layer of slack clean coal is discharged from the overflow port of the re-separation tank under the action of horizontal flow, and the bottom layer of slack gangue slides along the inclined tank bottom to the lump gangue area of the main separation tank, and the lump gangue and the slack gangue are discharged by the gangue discharge scraper of the gangue discharge assembly.

[0011] Preferably, the heavy medium feeding assembly comprises an upflow funnel, a horizontal flow medium tank and a pump; the heavy medium suspension stored in the medium barrel is sent into the upflow funnel and the horizontal flow medium tank by the pump, and the heavy medium suspension enters the main separation tank at a set speed ratio from the upflow funnel and the horizontal flow medium tank respectively; an inlet valve is arranged at the inlet of the upflow funnel and the horizontal flow medium tank, a plurality of upflow funnels are arranged at the bottom of the machine body in intervals, the horizontal flow medium tank is arranged at the upper end on one side along the length direction of the machine body, and a plurality of horizontal flow medium inlets are arranged at the upper end of the horizontal flow medium tank.

[0012] Preferably, the main separation tank is communicated with the feeding tank, the upflow funnel and the horizontal flow medium tank, a heavy liquid discharge hole is arranged at the upper side wall of the main separation tank, and the heavy liquid discharge hole is communicated with the re-separation tank.

[0013] Preferably, the re-separation tank is arranged on the side wall of the main separation tank and located on the side away from the horizontal flow medium tank, the lower end of the re-separation tank is a slope structure facing the direction of the main separation tank, and the bottom of the slope structure extends into the channel communicated between the re-separation tank and the main separation tank.

[0014] Preferably, the upper end surface of the re-separation tank is lower than the upper end surface of the main separation tank, the heavy liquid discharge hole is lower than the upper end surface of the re-separation tank, and the liquid level in the main separation tank is lower than the upper end surface thereof.

[0015] Preferably, the gangue discharge assembly comprises a driving wheel, a driving mechanism, a driven wheel, a gangue discharge scraper and a deflection wheel and a tensioning mechanism, the bottom of the gangue discharge scraper is arranged in the gangue area of the lower part of the inner cavity of the main separation tank, and the gangue discharge scraper rotates under the driving of the driving wheel, the driving mechanism, the driven wheel, the deflection wheel and the tensioning mechanism arranged on the machine body to discharge the lump gangue and the slack gangue in the gangue area from the separator.

[0016] Preferably, the rotating dial is rotatably connected to the sorting machine, the obliquely arranged rotating dial is located in the main sorting tank and close to one side of the re-sorting tank, the first end of the rotating dial extends to the outside of the upper end of the main sorting tank, and the second end of the rotating dial extends below the liquid level of the main sorting tank.

[0017] Preferably, the grate bar is obliquely arranged above the re-sorting tank, the upper end of the grate bar is connected to the upper end of the side wall of the main sorting tank, and the lower end of the grate bar is higher than the re-sorting tank and extends to the outside of the outer wall of the re-sorting tank; the aperture of the grate bar is 13 mm.

[0018] The present application also provides a heavy medium shallow tank cascade sorting method, comprising the following steps:

[0019] S1: The magnetite powder and water are configured into a heavy medium suspension according to a set ratio, stored in a qualified medium barrel, and sent into the heavy medium shallow tank cascade sorting machine by a pump;

[0020] S2: The heavy medium suspension is respectively fed into the main sorting tank according to a set speed from the upflow funnel and the horizontal flow medium tank, and then enters the re-sorting tank through the main sorting tank, and the heavy medium suspension is allowed to run stably in the tank body.

[0021] S3: The raw coal to be sorted is dropped into the main sorting tank from the feeding tank, and is fully contacted and mixed with the heavy medium suspension; based on the Archimedes principle, the block clean coal with a density lower than the heavy liquid and the slack coal which has not been sorted in time float on the upper liquid level of the main sorting tank, and the block gangue with a density higher than the heavy liquid gradually settles in the gangue area at the bottom of the main sorting tank;

[0022] S4: The block clean coal and the slack coal on the upper liquid level are scraped onto the grate bar by the obliquely arranged rotating dial;

[0023] S5: The block clean coal larger than the aperture of the grate bar rolls out of the sorting machine along the grate bar, and the slack coal smaller than the aperture of the grate bar falls into the re-sorting tank through the aperture of the grate bar to realize cascade sorting;

[0024] S6: Based on the Archimedes principle, the slack clean coal with a density lower than the heavy liquid floats on the upper liquid level of the re-sorting tank, and is discharged from the sorting machine through the slack clean coal overflow port of the re-sorting tank; the slack gangue with a density higher than the heavy liquid slides to the gangue area at the bottom of the main sorting tank through the inclined surface structure;

[0025] S7: The gangue area block gangue and the slack gangue are discharged from the sorting machine by the gangue scraping plate.

[0026] Compared with the prior art, the present application has the following beneficial effects:

[0027] The application is provided with a main sorting groove and a re-sorting groove, and the re-sorting groove 13-6mm coal is supplied by rotating the dial wheel + grate bar, the main sorting groove and the re-sorting groove can realize the cascade dense medium separation of 200(300)-6mm particle size coal, effectively reducing the lower limit of the sorting particle size of the dense medium shallow groove; compared with the traditional 200(300)-13mm particle size lump coal dense medium shallow groove sorting and 13-6mm particle size fine coal dense medium cyclone sorting process, the application can simplify the process, without additional fine coal dense medium sorting system, and can effectively reduce the production cost of the coal preparation plant. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0029] Figure 1 is the front view of the present application;

[0030] Figure 2 is the left view of the present application;

[0031] Figure 3 is the top view of the present application.

[0032] In the figure: 1-machine body; 1.1-feeding groove; 2.1-upstream funnel; 2.2-horizontal flow medium groove; 3-main sorting groove; 3.1-heavy liquid discharge hole; 4-re-sorting groove; 5.1-driving wheel; 5.2-driving mechanism; 5.3-driven wheel; 5.4-gangue scraping plate; 5.5-reversing wheel and tensioning mechanism; 6-inclined rotating dial wheel; 7-grate bar. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application are described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of the present application.

[0034] It is to be understood that the structures, proportions, sizes, etc. shown in the drawings of the present specification are merely used to cooperate with the disclosed content, to be understood and read by those skilled in the art, and are not used to limit the implementation conditions of the present application, so they do not have technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effect and purpose that can be achieved by the present application, should fall within the scope of the disclosed technical content. It should be noted that in the present specification, relationship terms such as first and second are merely used to distinguish one entity from another, and do not necessarily require or imply any actual relationship or order between the entities.

[0035] The present application provides an embodiment:

[0036] A heavy medium shallow slot step separator, comprising a machine body 1 and a heavy medium feeding assembly, a main separation slot 3, a re-separation slot 4, a gangue discharging assembly, a rotating scraper 6 and a grate 7 arranged on the machine body 1;

[0037] Wherein a feeding slot 1.1 for the raw material to be separated to enter the main separation slot 3 is arranged at the machine body;

[0038] The heavy medium feeding assembly is used to provide heavy medium suspension into the main separation slot 3 and the re-separation slot 4;

[0039] The raw material to be separated is separated into upper layer of lump clean coal and slack coal and bottom layer of lump gangue in the heavy medium suspension in the main separation slot 3.1 based on the Archimedes principle;

[0040] The upper layer of lump clean coal and slack coal is scraped to the grate 7 by the obliquely arranged rotating scraper 6, the slack coal falls into the re-separation slot 4 below through the screen hole of the grate 7, and the lump clean coal slides downward along the inclined grate 7; the separated slack coal is further separated into layers according to the density difference in the heavy medium suspension in the re-separation slot 4 based on the Archimedes principle, the upper layer of slack clean coal is discharged from the overflow port of the re-separation slot 4 under the action of horizontal flow, and the bottom layer of slack gangue slides along the inclined slot bottom to the lump gangue area of the main separation slot 3, and the lump gangue and slack gangue are discharged by the gangue discharging scraper 5.4 of the gangue discharging assembly.

[0041] The present application can reduce the lower limit of the heavy medium shallow slot separation particle size, effectively improve the separation effect of 13-6mm particle size coal, and realize high-efficiency heavy medium shallow slot separation of 200(300)-6mm particle size raw coal; for the coal preparation plant using 200(300)-13mm particle size raw coal heavy medium shallow slot separation and 13-6mm particle size raw coal slack coal heavy medium cyclone separation, the present application can effectively reduce the complexity of the coal preparation process and reduce the production cost.

[0042] In the embodiment, the heavy medium feeding assembly comprises an up-flow funnel 2.1, a horizontal flow medium tank 2.2 and a pump machine; the heavy medium suspension stored in the medium barrel is sent into the up-flow funnel 2.1 and the horizontal flow medium tank 2.2 by the pump machine, and the heavy medium suspension enters the main sorting tank 3.1 at a set speed ratio from the up-flow funnel 2.1 and the horizontal flow medium tank 2.2 respectively; the inlet of the up-flow funnel 2.1 and the horizontal flow medium tank 2.2 is provided with a feeding valve, a plurality of up-flow funnels 2.1 are arranged at intervals at the bottom of the machine body 1, and the horizontal flow medium tank 2.2 is arranged at the upper end on one side along the length direction of the machine body 1, and a plurality of horizontal flow medium feeding ports are arranged on the upper end of the horizontal flow medium tank 2.2.

[0043] The main sorting tank 3 is communicated with the feeding tank 1.1, the up-flow funnel 2.1 and the horizontal flow medium tank 2.2, the upper side wall of the main sorting tank 3 is provided with a heavy liquid discharge hole 3.1, and the heavy liquid discharge hole 3.1 is communicated with the re-sorting tank 4. The re-sorting tank 4 is arranged on the side wall of the main sorting tank 3 and located on the side away from the horizontal flow medium tank, the lower end of the re-sorting tank 4 is a slope structure facing the direction of the main sorting tank 3, and the bottom of the slope structure extends into the channel of the re-sorting tank 4 communicated with the main sorting tank 3.1. The upper end surface of the re-sorting tank 4 is lower than the upper end surface of the main sorting tank 3, the heavy liquid discharge hole 3.1 is lower than the upper end surface of the re-sorting tank 4, and the liquid level in the main sorting tank 3 is lower than the upper end surface thereof.

[0044] The gangue discharging assembly comprises a driving wheel 5.1, a driving mechanism 5.2, a driven wheel 5.3, a gangue discharging scraper 5.4 and a deflection wheel and tensioning mechanism 5.5, the bottom of the gangue discharging scraper 5.4 is arranged in the gangue area of the lower part of the inner cavity of the main sorting tank 4, and the gangue discharging scraper 5.4 rotates under the driving of the driving wheel 5.1, the driving mechanism 5.2, the driven wheel 5.3 and the deflection wheel and tensioning mechanism 5.5 arranged on the machine body 1 to discharge the block gangue and the end gangue in the gangue area out of the sorting machine.

[0045] The rotating push wheel 6 is rotatably connected to the sorting machine, the obliquely arranged rotating push wheel 6 is located in the main sorting tank 3 and close to one side of the re-sorting tank 4, the first end of the rotating push wheel 6 extends to the outside of the upper end of the main sorting tank 3, and the second end of the rotating push wheel 6 extends below the liquid level of the main sorting tank 3.

[0046] The grate bar 7 is arranged obliquely above the re-sorting tank 4, the upper end of the grate bar 7 is connected to the upper end of the side wall of the main sorting tank 3, and the lower end of the grate bar 7 is higher than the re-sorting tank 4 and extends to the outside of the outer wall of the re-sorting tank 4; the aperture of the grate bar 7 is 13 mm.

[0047] The most important improvement of the present application compared with the traditional heavy medium shallow slot separator is that a tilt-arranged rotating raking wheel 6 is additionally arranged at the overflow port of the raw clean coal, which scrapes the well-separated lump clean coal and the not fully separated fine clean coal to the grate bar 7 with a certain tilt angle and a hole diameter of 13 mm; due to the existence of the hole diameter on the grate bar, the lump clean coal larger than 13 mm will roll along the grate bar, and the fine coal smaller than 13 mm will fall through the hole to the auxiliary slot (fine coal separation slot) to realize the cascade separation; there is a certain height difference between the main separation slot and the re-separation slot, the heavy liquid in the main separation slot flows to the re-separation slot through the heavy liquid overflow slot to provide the environment for the fine coal separation; the overflow product of the re-separation slot is the fine clean coal, and the bottom of the re-separation slot is a tilt slot surface, the fine gangue slides to the lump gangue area of the main separation slot through the tilt slot surface, and is scraped out by the scraper as the final gangue product.

[0048] The present application also provides a heavy medium shallow slot cascade separation method, comprising the following steps:

[0049] S1: configure the magnetite powder and water into heavy medium suspension according to the set ratio, store in the qualified medium barrel, and send into the heavy medium shallow slot cascade separator by the pump;

[0050] S2: the heavy medium suspension enters the main separation slot 3.1 from the ascending flow funnel 2.1 and the horizontal flow medium slot 2.2 at a set speed ratio, and then enters the re-separation slot 4 through the main separation slot 3.1, and waits for the heavy medium suspension to run stably in the slot body.

[0051] S3: the raw coal to be separated falls into the main separation slot 3 from the feeding slot 1.1, and fully contacts and mixes with the heavy medium suspension; based on the Archimedes principle, the lump clean coal with a density lower than the heavy liquid and the fine coal which has not been separated float on the upper liquid surface of the main separation slot 3, and the lump gangue with a density higher than the heavy liquid gradually settles in the gangue area at the bottom of the main separation slot 3;

[0052] S4: the lump clean coal and the fine coal on the upper liquid surface are scraped to the grate bar 7 by the tilt-arranged rotating raking wheel 6;

[0053] S5: the lump clean coal larger than the hole diameter of the grate bar 7 rolls out of the separator along the grate bar 7, and the fine coal smaller than the hole diameter of the grate bar 7 falls into the re-separation slot 4 through the hole of the grate bar 7 to realize the cascade separation;

[0054] S6: based on the Archimedes principle, the fine clean coal with a density lower than the heavy liquid floats on the upper liquid surface of the re-separation slot 4, and is discharged from the separator through the fine clean coal overflow port of the re-separation slot 4; the fine gangue with a density higher than the heavy liquid slides to the gangue area at the bottom of the main separation slot 3 through the inclined surface structure;

[0055] S7: the gangue area lump gangue and fine gangue are discharged from the separator by the gangue scraping plate 5.4.

[0056] The present application proposes a new structure of heavy medium shallow slot step sorting machine, which lowers the lower limit of sorting granularity of the heavy medium shallow slot sorting machine to 6mm, and realizes high-efficient heavy medium shallow slot sorting of 200(300)-6mm particle size coal;

[0057] One of the cores is to design a set of rotating dials at the overflow port of the conventional lump clean coal, which is used to scrape the well sorted lump clean coal and the not fully sorted fine coal to the grate bars with a certain inclination angle and a hole diameter of 13mm; due to the existence of the hole diameter on the grate bars, the lump clean coal larger than 13mm will roll down along the grate bars, and the fine coal smaller than 13mm will fall into the auxiliary groove (fine coal sorting groove) through the hole diameter to realize step sorting;

[0058] The second core is to design a set of re-sorting grooves, which create a suitable fluid mechanics environment for the 13-6mm particle size coal sorting, and strengthen the high-efficient sorting of the 13-6mm particle size coal.

[0059] The above is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A shallow-tank heavy medium cascade sorting machine, characterized in that: It includes a machine body (1) and a heavy medium feeding assembly, a main sorting tank (3), a re-sorting tank (4), a waste removal assembly, a rotating wheel (6), and a grate (7) installed on the machine body (1); The heavy medium feeding assembly includes an upward flow funnel (2.1), a horizontal flow medium tank (2.2), and a pump. The heavy medium suspension stored in the medium tank is pumped into the upward flow funnel (2.1) and the horizontal flow medium tank (2.2). The heavy medium suspension enters the main sorting tank (3) from the upward flow funnel (2.1) and the horizontal flow medium tank (2.2) at a set speed ratio. The machine body is equipped with a feed trough (1.1) for the raw materials to be sorted to enter the main sorting tank (3). The heavy media feed assembly is used to supply heavy media suspension to the main sorting tank (3) and the resorting tank (4); Based on Archimedes' principle, the raw materials to be sorted are divided into upper layer of lump coal and some unsorted fine coal and bottom layer of lump gangue in the heavy medium suspension in the main sorting tank (3). A rotating wheel (6) is rotatably connected to the sorting machine. The inclined rotating wheel (6) is located in the main sorting tank (3) and close to the side of the re-sorting tank (4). The first end of the rotating wheel (6) extends to the outer side of the upper end of the main sorting tank (3), and the second end of the rotating wheel (6) extends into the liquid surface of the main sorting tank (3). The grate bar (7) is obliquely set above the re-sorting tank (4). The upper end of the grate bar (7) is connected to the upper side wall of the main sorting tank (3), and the lower end of the grate bar (7) is higher than the re-sorting tank (4) and extends to the outer side of the outer wall of the re-sorting tank (4). The aperture of the grate bar (7) is 13mm. The upper layer of lump coal and fine coal is scraped onto the grate bar (7) by the inclined rotating wheel (6). The fine coal falls through the screen holes of the grate bar (7) into the lower re-sorting tank (4), while the lump coal slides down the grate bar (7) at an incline. The separated fine coal is further stratified according to density difference in the heavy medium suspension in the re-sorting tank (4) based on Archimedes' principle. The upper layer of fine coal is discharged from the overflow port of the re-sorting tank (4) under the action of horizontal flow. The bottom layer of gangue slides down the inclined bottom of the tank to the lump gangue area of ​​the main sorting tank (3), and the gangue scraper (5.4) of the gangue discharge assembly discharges the lump gangue and the fine gangue.

2. The heavy medium shallow trough step sorting machine according to claim 1, characterized in that: Both the inlet of the rising flow funnel (2.1) and the horizontal flow medium tank (2.2) are equipped with feed valves. Multiple rising flow funnels (2.1) are spaced apart at the bottom of the machine body (1). The horizontal flow medium tank (2.2) is located on the upper side along the length of the machine body (1), and multiple horizontal flow medium inlets are provided at the upper end of the horizontal flow medium tank (2.2).

3. The heavy medium shallow trough step sorting machine according to claim 2, characterized in that: The main sorting tank (3) is connected to the feed tank (1.1), the rising flow funnel (2.1) and the horizontal flow medium tank (2.2). A heavy liquid discharge hole (3.1) is provided on the upper side wall of the main sorting tank (3), and the heavy liquid discharge hole (3.1) is connected to the re-sorting tank (4).

4. The heavy medium shallow trough step sorting machine according to claim 3, characterized in that: The re-sorting tank (4) is set on the side wall of the main sorting tank (3) and located away from the horizontal flow medium tank. The lower end of the re-sorting tank (4) is an inclined structure facing the main sorting tank (3), and the bottom of the inclined structure extends into the channel connecting the re-sorting tank (4) and the main sorting tank (3).

5. A heavy medium shallow trough step sorting machine according to claim 3, characterized in that: The upper end face of the re-sorting tank (4) is lower than the upper end face of the main sorting tank (3), the heavy liquid discharge hole (3.1) is lower than the upper end face of the re-sorting tank (4), and the liquid level in the main sorting tank (3) is lower than its upper end face.

6. The heavy medium shallow trough step sorting machine according to claim 1, characterized in that: The gangue removal assembly includes a drive wheel (5.1), a drive mechanism (5.2), a driven wheel (5.3), a gangue removal scraper (5.4), a redirecting wheel, and a tensioning mechanism (5.5). The bottom of the gangue removal scraper (5.4) is provided with the gangue area in the lower part of the inner cavity of the main sorting trough (3). The gangue removal scraper (5.4) rotates under the drive of the drive wheel (5.1), drive mechanism (5.2), driven wheel (5.3), redirecting wheel, and tensioning mechanism (5.5) set on the machine body (1), thereby discharging the block gangue and the final gangue from the gangue area from the sorting machine.

7. A method for heavy medium shallow trough step sorting, based on the heavy medium shallow trough step sorting machine as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1: Magnetite powder and water are mixed in a set ratio to form a heavy medium suspension, which is stored in a qualified medium tank and then pumped into a heavy medium shallow tank cascade separator. S2: The heavy medium suspension enters the main sorting tank (3) from the rising flow funnel (2.1) and the horizontal flow medium tank (2.2) at a set speed ratio, and then enters the re-sorting tank (4) through the main sorting tank (3) until the heavy medium suspension runs stably in the tank. S3: The raw coal to be sorted is dropped from the feed trough (1.1) into the main sorting tank (3) and fully mixed with the heavy medium suspension. Based on Archimedes' principle, the raw coal in the tank, the lump coal with a density lower than that of the heavy liquid and the fine coal that has not yet been sorted float on the upper liquid surface of the main sorting tank (3), while the lump gangue with a density higher than that of the heavy liquid gradually sinks to the gangue area at the bottom of the main sorting tank (3). S4: The lump coal and fine coal located on the upper liquid surface are scraped onto the grate bar (7) by the inclined rotating wheel (6); S5: Lump coal larger than the aperture of the grate bar (7) rolls out of the separator along the grate bar (7), while fine coal smaller than the aperture of the grate bar (7) passes through the holes of the grate bar (7) and falls into the re-separation tank (4) to achieve tiered separation. S6: Based on Archimedes' principle, the fine coal with a density lower than that of heavy liquid floats on the upper liquid surface of the re-sorting tank (4) and is discharged from the separator through the fine coal overflow port of the re-sorting tank (4); the fine gangue with a density higher than that of heavy liquid slides down to the gangue area at the bottom of the main sorting tank (3) through the inclined structure. S7: The waste scraper (5.4) discharges the block waste and the final waste from the waste area into the sorting machine.

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