A two-stage heavy medium separation system and method for coarse slime

Abstract

The application provides a coarse slime two-stage heavy medium separation system and a separation method. The separation system comprises a heavy medium feeding subsystem, a heavy medium separation subsystem, a clean coal extraction subsystem and a tail coal extraction subsystem. The heavy medium separation subsystem comprises a slime heavy medium cyclone and a heavy medium interference bed separator. The heavy medium feeding subsystem comprises a qualified medium barrel, a first feeding pipeline, a first flow regulating valve, a second feeding pipeline, a second flow regulating valve and at least one qualified medium feeding pump. The inlet of the qualified medium feeding pump is connected with the qualified medium barrel. The outlet is connected with a medium feeding port of the slime heavy medium cyclone and an ascending medium inlet of the heavy medium interference bed separator through the first feeding pipeline and the second feeding pipeline respectively. The first flow regulating valve and the second flow regulating valve are arranged on the first feeding pipeline and the second feeding pipeline respectively. The separation system provided by the application can efficiently and accurately realize two-stage heavy medium separation of the slime.

Description

Technical Field

[0001] The present application belongs to the technical field of heavy medium coal separation, and specifically provides a coarse coal slime two-stage heavy medium separation system and separation method. Background Art

[0002] As the properties of raw coal become increasingly complex and coal mining technology becomes more mechanized, the content of coal slime in raw coal is increasing. "Effective separation" of coal slime in raw coal has become a key issue in the work of various coal preparation plants. At present, how to achieve efficient separation of coarse coal slime with a particle size of 1.0mm to 0.2mm has attracted widespread attention in the coal preparation industry. Various scientific research institutions and enterprises at home and abroad have set foot in this field, and related new products and new processes have also been introduced and put into use. The coal slime separation equipment that is more widely used now includes coal slime heavy medium cyclone, spiral separator, heavy medium interference bed separator and coal slime heavy medium separation system composed of the above equipment.

[0003] Patent CN105597914A discloses a heavy medium interference bed coarse coal slime sorting system, which consists of a two-stage sorting structure consisting of a cascaded coal slime water classification cyclone and a heavy medium interference bed separator. After the underflow of the coal slime water classification cyclone enters the heavy medium interference bed separator, the clean coal and medium coal (or gangue) are recovered through the overflow and underflow of the heavy medium interference bed respectively.

[0004] Although the above-mentioned sorting system can process coarse coal slime through the heavy medium interference bed separator and broaden the feed particle size range of the heavy medium interference bed separator, the coal slime water grading cyclone and the heavy medium interference bed separator in its two-stage sorting structure need to be equipped with independent coal slime water buckets and qualified medium buckets. In particular, the mixing of coal slime water requires a separate mixing bucket and mixing pump, which makes the structure and treatment process of the feed part complicated and the operating energy consumption increased. At the same time, over-crushing problems are prone to occur during the mixing and transportation of coal slime. In addition, since the coal slime content in the raw coal changes all the time and the diversion flow fluctuates greatly, the above-mentioned independent feed and output pipelines cannot form a feedback adjustment mechanism. Therefore, when the properties of the peat water change significantly, it is difficult to quickly and accurately adjust the feed of the heavy medium interference bed separator. Summary of the Invention

[0005] In order to solve the problems existing in the above-mentioned prior art, the present application provides a coarse coal slime two-stage heavy medium separation system through an embodiment, which includes a heavy medium feeding subsystem, a heavy medium separation subsystem, a clean coal extraction subsystem and a tail coal extraction subsystem;

[0006] The heavy medium separation subsystem includes a coal slime heavy medium cyclone and a heavy medium interference bed separator. A coal slime feeding funnel is provided on the upper part of the coal slime heavy medium cyclone. The overflow port is connected to the clean coal extraction subsystem, and the underflow port is connected to the feed port of the heavy medium interference bed separator. The overflow port and underflow port of the heavy medium interference bed separator are connected to the clean coal extraction subsystem and the tail coal extraction subsystem respectively.

[0007] The heavy medium feeding subsystem includes a qualified medium barrel, a first feeding pipeline, a first flow regulating valve, a second feeding pipeline, a second flow regulating valve and at least one qualified medium feeding pump, wherein the inlet of the qualified medium feeding pump is connected to the qualified medium barrel, and the outlet is connected to the medium feeding port of the coal slime heavy medium cyclone and the rising medium inlet of the heavy medium interference bed separator through the first feeding pipeline and the second feeding pipeline respectively, and the first flow regulating valve and the second flow regulating valve are respectively arranged on the first feeding pipeline and the second feeding pipeline.

[0008] Preferably, the density ratio of the first heavy medium suspension entering the coal slime heavy medium cyclone through the first feeding pipeline to the second heavy medium suspension entering the heavy medium interference bed separator through the second feeding pipeline is 1.1-1.5.

[0009] Preferably, a first density meter is further provided on the first feed pipeline, and a second density meter and a first clean water regulating valve are further provided on the second feed pipeline; the first clean water regulating valve is located at the front end of the second density meter on the second feed pipeline.

[0010] Preferably, there are two qualified medium feed pumps, namely a first qualified medium feed pump and a second qualified medium feed pump; wherein, the outlet of the first qualified medium feed pump is connected to the first feed pipeline, and the outlet of the second qualified medium feed pump is connected to the second feed pipeline.

[0011] Preferably, the connection position of the second qualified medium feeding pump and the qualified medium barrel is higher than the connection position of the first qualified medium feeding pump and the qualified medium barrel.

[0012] Preferably, the heavy medium feeding subsystem further includes a third feeding pipeline, a pre-swirl wetting pipe and a third flow regulating valve;

[0013] One end of the third feed pipeline is connected to the outlet of the qualified medium feed pump, and the other end is connected to the pre-swirl wetting pipe. The third flow regulating valve is arranged on the third feed pipeline, and the pre-swirl wetting pipe passes through and enters the interior of the coal slime feed funnel.

[0014] Preferably, the density of the third heavy medium suspension entering the coal slime feeding funnel through the pre-swirl wetting pipe is not greater than the density of the first heavy medium suspension.

[0015] Preferably, a water replenishing valve and a medium powder replenishing device are provided on the top of the qualified medium barrel, and a liquid level meter is provided inside.

[0016] Preferably, the clean coal extraction subsystem includes a clean coal de-medium laminated high-frequency fine screen, a clean coal magnetic separator, a clean coal laminated high-frequency fine screen, and a clean coal slime centrifugal dewatering machine; the overflow ports of the coal slime heavy medium cyclone and the heavy medium interference bed separator are connected to the clean coal de-medium laminated high-frequency fine screen, the undersize of the clean coal de-medium laminated high-frequency fine screen returns to the qualified medium barrel, and the oversize enters the clean coal magnetic separator; the concentrate product of the clean coal magnetic separator returns to the qualified medium barrel, and the tailings product enters the clean coal laminated high-frequency fine screen; the oversize of the clean coal laminated high-frequency fine screen enters the clean coal slime centrifugal dewatering machine, and the undersize enters the flotation machine; the dehydration product of the clean coal slime centrifugal dewatering machine is clean coal, and the centrifugal liquid enters the flotation machine.

[0017] Preferably, the clean coal extraction subsystem further comprises a diverter valve for diverting the undersize of the clean coal de-intermediation laminated high-frequency fine screen to the clean coal magnetic separator.

[0018] Preferably, the tail coal extraction subsystem includes a tail coal de-medium laminated high-frequency fine screen, a tail coal magnetic separator, a tail coal laminated high-frequency fine screen, and a tail coal slime centrifugal dewatering machine; the bottom flow port of the heavy medium interference bed separator is connected to the tail coal de-medium laminated high-frequency fine screen, the undersize of the tail coal de-medium laminated high-frequency fine screen is returned to the qualified medium barrel, and the oversize enters the tail coal magnetic separator; the concentrate product of the tail coal magnetic separator is returned to the qualified medium barrel, and the tailings product enters the tail coal laminated high-frequency fine screen; the oversize of the tail coal laminated high-frequency fine screen enters the tail coal slime centrifugal dewatering machine, and the undersize enters the concentrator; the dehydration product of the tail coal slime centrifugal dewatering machine is tail coal, and the centrifugal liquid enters the concentrator.

[0019] The present application also provides a two-stage heavy medium separation method for coarse coal slime through an embodiment, comprising the following steps:

[0020] A1: The qualified medium suspension in the qualified medium barrel passes through the qualified medium feed pump and the first feed pipeline and enters the medium feed port of the coal slime heavy medium cyclone at a first flow rate, a first pressure, and a first density. The selected coal slime flows by its own gravity through the coal slime feed funnel and enters the coal slime heavy medium cyclone for primary separation.

[0021] A2: The underflow product of the coal slime heavy medium cyclone enters the heavy medium interference bed separator for secondary separation. The qualified medium suspension in the qualified medium barrel passes through the qualified medium feed pump and the second feed pipeline and enters the rising medium inlet of the heavy medium interference bed separator at the second flow rate, second pressure and second density.

[0022] A3. The overflow product from the coal slime heavy medium cyclone and the overflow product from the heavy medium interference bed separator are combined and fed into the clean coal de-intermediation laminated high-frequency fine screen for de-intermediation treatment. The undersize material from the clean coal de-intermediation laminated high-frequency fine screen is returned to the qualified medium barrel. The oversize material from the clean coal de-intermediation laminated high-frequency fine screen is diluted with clean water and fed into the clean coal magnetic separator for medium recovery. The concentrate from the clean coal magnetic separator is returned to the qualified medium barrel. The tailings from the clean coal magnetic separator are fed into the clean coal laminated high-frequency fine screen for dehydration and desliming. The oversize material from the clean coal laminated high-frequency fine screen is fed into the clean coal slime centrifugal dehydrator for final moisture control. The dehydrated product from the clean coal slime centrifugal dehydrator becomes qualified clean coal. The undersize material from the clean coal laminated high-frequency fine screen and the centrifugal liquid from the clean coal slime centrifugal dehydrator are fed into the flotation machine.

[0023] A4. The underflow product of the heavy medium interference bed separator enters the tailings de-mediumizing laminated high-frequency fine screen for de-mediumizing treatment. The undersize material of the tailings de-mediumizing laminated high-frequency fine screen is returned to the qualified medium barrel. The oversize material of the tailings de-mediumizing laminated high-frequency fine screen is diluted with clean water and enters the tailings magnetic separator for medium recovery operation. The concentrate of the tailings magnetic separator returns to the qualified medium barrel. The tailings of the tailings magnetic separator enter the tailings laminated high-frequency fine screen for dehydration and desliming treatment. The oversize material of the tailings laminated high-frequency fine screen enters the tailings slime centrifugal dehydrator for final moisture control and becomes the tailings product. The undersize material of the tailings laminated high-frequency fine screen and the centrifugal liquid of the tailings slime centrifugal dehydrator enter the concentrator.

[0024] Preferably, the coarse coal slime two-stage heavy medium separation method further comprises the following steps:

[0025] A11, the qualified medium suspension in the qualified medium barrel passes through the qualified medium feed pump and the third feed pipeline, and enters the coal slime feed funnel of the coal slime heavy medium cyclone along the tangential direction according to the flow rate, the third pressure and the third density.

[0026] The coarse coal slime two-stage heavy medium separation system provided in this embodiment optimizes the separation device cascade architecture and feed structure of the existing coarse coal slime heavy medium separation system, and adopts two-stage heavy medium separation devices with different medium densities to separate the coal slime. Compared with the existing solution of using the hydrocyclone as the first-stage separation device, it can effectively improve the recovery rate of the clean coal product; at the same time, only one qualified medium barrel is used to provide heavy medium suspension for the two-stage heavy medium separation devices at the same time, and the qualified medium suspension is fed into the coal slime heavy medium cyclone and the second stage heavy medium separation device respectively by a qualified medium pump in a pressurized manner. In the heavy medium interference bed separator, the selected coal slime adopts a pressure-free feeding method and enters the coal slime heavy medium cyclone by its own gravity. Therefore, there is no need to set up a mixing barrel to mix the qualified medium suspension with the selected coal slime, which effectively reduces the number of equipment and operating energy consumption. In addition, the medium components obtained after de-mediation and magnetic separation of the products of the two-stage heavy medium separation device are returned to the qualified medium barrel, forming a feedback adjustment closed loop for the concentration of the heavy medium suspension, which can quickly and accurately adjust the density of the heavy medium suspension entering the two-stage heavy medium separation device according to the changes in the composition of the selected coal slime. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the framework of an existing dense medium interference bed separation system;

[0028] Figure 2 This is a schematic diagram of the framework of a two-stage heavy medium separation system for coarse coal slime provided according to the first embodiment of the present application;

[0029] Figure 3 This is a schematic diagram of the framework of a two-stage heavy medium separation system for coarse coal slime provided according to the second embodiment of the present application;

[0030] Figure 4 This is a schematic diagram of the framework of a two-stage heavy medium separation system for coarse coal slime provided according to the third embodiment of the present application;

[0031] Figure 5 This is a schematic diagram of a coarse coal slime dense medium cyclone provided according to a third embodiment of the present application;

[0032] Figure 6 The present invention provides a flowchart of a two-stage heavy medium separation method for coarse coal slime according to an embodiment of the present application.

[0033] Numbers in the figure

[0034] Qualified medium barrel 1, first qualified medium feeding pump 21, second qualified medium feeding pump 22, first feeding pipeline 31, first flow regulating valve 311, first magnetic content meter 312, first density meter 313, first pressure transmitter 314, second feeding pipeline 32, second flow regulating valve 321, second magnetic content meter 322, second density meter 323, second pressure transmitter 324, first clean water regulating valve 325, third feeding pipeline 33, third flow regulating valve 331, third magnetic content meter 332, third density meter 333, third pressure transmitter 334, pre-cyclone wetting tube 335, coal slime heavy medium cyclone 4, cylinder 41, medium feed port 42, overflow port 43, underflow port 44, coal slime feed funnel 45, feed pipe 46, bracket 47, heavy medium interference bed separator 5, clean coal de-medium laminated high-frequency fine screen 61, clean coal magnetic separator 62, clean coal laminated high-frequency fine screen 63, clean coal slime centrifugal dewatering machine 64, diverter valve 65, tail coal de-medium laminated high-frequency fine screen 71, tail coal magnetic separator 72, tail coal laminated high-frequency fine screen 73, tail coal slime centrifugal dewatering machine 74. DETAILED DESCRIPTION

[0035] Hereinafter, the present application will be further described based on preferred embodiments with reference to the accompanying drawings.

[0036] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "inner", "outer" and the like indicate an orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or are the orientation or positional relationship in which the products of the embodiments of the present application are usually placed when in use, they are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, in the description of the present application, in order to distinguish different units, words such as first and second are used in this specification, but these are not limited by the order of manufacture, nor can they be understood as indicating or implying relative importance. Their names may be different in the detailed description and claims of the present application.

[0037] The vocabulary in this specification is used to illustrate the embodiments of the present application, but is not intended to limit the present application. It should also be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, an indirect connection through an intermediate medium, or a communication between the two components. For those skilled in the art, the specific meanings of the above terms in this application can be specifically understood.

[0038] Figure 1The schematic diagram of the structure of an existing heavy medium interference bed coarse coal slime separation system is shown in FIG. Figure 1 As shown, the heavy medium interference bed coarse coal slime separation system is provided with a cascade of coal slime water classification cyclone 3' and heavy medium interference bed separator 4', wherein the feed of the coal slime water classification cyclone 3' is the coal slime water slurry pumped in through the coal slime water bucket 1', the overflow of which enters the flotation machine, and the bottom flow enters the heavy medium interference bed separator 4', the heavy medium interference bed separator 4' receives the rising medium flow from the heavy medium suspension barrel 5', and the slurry containing the clean coal component obtained after sorting passes through the clean coal arc de-mediation screen 8', the clean coal magnetic separator 8' and the like in sequence. After passing through the separator 10', the clean coal curved dewatering screen 12', the clean coal high-frequency dewatering screen 14', and the clean coal centrifugal dewatering machine 15', the clean coal product is finally obtained; the slurry containing medium coal (or gangue) components passes through the medium coal (or gangue) curved de-mediation screen 7', the medium coal (or gangue) magnetic separator 9', the medium coal (or gangue) curved dewatering screen 11', and the medium coal (or gangue) high-frequency vibration dewatering screen 13' to obtain the medium coal (or gangue) product; in the above process, the medium obtained by de-mediation and magnetic separation is returned to the heavy medium suspension tank. The detailed implementation of the heavy medium interference bed coarse coal slime sorting system can be referred to the Chinese invention patent No. 201610151938.2 previously applied for by the same applicant.

[0039] Although the above-mentioned separation system can process coarse coal slime and expand the feed particle size range through the heavy medium interference bed separator, the following problems still exist during its use, which affect the separation efficiency and effect:

[0040] 1) In the two-stage separation structure of the coarse coal slime separation system, the coal slime water classification cyclone and the heavy medium interference bed separator require independent coal slime water buckets and qualified medium buckets. In particular, the mixing of coal slime water requires a separate mixing bucket and mixing pump, which makes the feeding structure and processing process complicated and increases the operating energy consumption.

[0041] 2) Coal slurry needs to be mixed with water in the early stage by stirring coarse coal slurry particles. During the stirring, mixing and transportation process, over-crushing problems are prone to occur, which increases the content of fine coal in the overflow of the coal slurry water classification cyclone entering the flotation operation, but reduces the effective identity of the high-concentration underflow entering the heavy medium interference bed separator, making the separation capacity of the heavy medium interference bed unable to be effectively utilized;

[0042] 3) After the coarse coal slime slurry passes through the coal slime water classification cyclone, its overflow directly enters the flotation process, that is, the feed pipeline and output pipeline of the two-stage separation structure are independent of each other and cannot form feedback adjustment. However, the coal slime content in the raw coal changes all the time, and the diversion flow fluctuates greatly. When the properties of the peat water change significantly, the above structure is difficult to adaptively and accurately adjust the feed of the heavy medium interference bed separator through the feedback mechanism.

[0043] To this end, the present application provides a novel two-stage heavy medium separation system for coarse coal slime to solve the above problems. The following is a detailed introduction to the separation system in conjunction with the accompanying drawings and preferred embodiments.

[0044] First embodiment

[0045] Figure 2 This is a schematic diagram of the framework of a two-stage heavy medium separation system for coarse coal slime according to the first embodiment of the present application. Figure 2 As shown, the separation system includes a heavy medium feeding subsystem, a coal slime heavy medium cyclone 4, a heavy medium interference bed separator 5, a clean coal extraction subsystem and a tail coal extraction subsystem.

[0046] <Heavy medium feeding subsystem>

[0047] The heavy medium feeding subsystem is used to provide heavy medium suspension for the two-stage separation equipment in the heavy medium separation subsystem, namely the coal slime heavy medium cyclone 4 and the heavy medium interference bed separator 5 described later.

[0048] Specifically, the heavy medium feeding subsystem includes a qualified medium barrel 1, a first qualified medium feeding pump 21, a first feeding pipeline 31, and a second feeding pipeline 32. The inlet of the first qualified medium feeding pump 21 is connected to the qualified medium barrel 1, and the outlet is connected to the medium feeding port of the coal slime heavy medium cyclone 4 and the rising medium inlet of the heavy medium interference bed separator 5 through the first feeding pipeline 31 and the second feeding pipeline 32, respectively, to pump the heavy medium slurry in the qualified medium barrel 1 into the coal slime heavy medium cyclone 4 and the heavy medium interference bed separator 5, respectively.

[0049] In some preferred embodiments, a liquid level meter, a water replenishing valve and a medium powder replenishing device are provided on the qualified medium barrel 1. The liquid level meter is locked with the automatic water replenishing valve and the medium powder replenishing device. When the liquid level in the qualified medium barrel 1 is lower than the preset lower limit (such as 50%), the new heavy medium suspension is replenished according to the preset ratio through the water replenishing valve and the medium powder replenishing device. When the liquid level in the qualified medium barrel 1 reaches the preset upper limit (such as 80%), it is automatically closed, thereby achieving normal liquid level and ensuring stable production.

[0050] In some preferred embodiments, a high-pressure air blowing device is further provided at the bottom of the qualified medium barrel 1 to prevent the magnetite powder from settling and causing material accumulation problems.

[0051] In some preferred embodiments, the qualified medium barrel 1 also has a pipeline connected to the clean coal de-medium laminated high-frequency fine screen 61, the clean coal magnetic separator 62, the tail coal de-medium laminated high-frequency fine screen 71 and / or the tail coal magnetic separator 72, for receiving the slurry containing magnetic medium obtained after the above-mentioned equipment performs de-mediuming and magnetic separation operations.

[0052] Furthermore, a first flow regulating valve 311 and a second flow regulating valve 321 are respectively provided on the first feed pipeline 31 and the second feed pipeline 32. The regulating valves can be electrically controlled to adjust the flow of the heavy medium slurry flowing through the first feed pipeline 31 and the second feed pipeline 32.

[0053] Preferably, a first magnetic content meter 312 and a first density meter 313 are also provided on the first feed pipeline 31, and a second magnetic content meter 322 and a second density meter 323 are also provided on the second feed pipeline 32. A density meter and a magnetic content meter are respectively provided on the first feed pipeline 31 entering the coal slime heavy medium cyclone 4 and the second feed pipeline 32 entering the heavy medium interference bed separator 5. The density and magnetic content of the qualified medium suspension can be detected online, and the density and magnetic content of the qualified medium suspension on each feed pipeline can be adjusted by adding water or medium.

[0054] Preferably, a first pressure transmitter 314 is provided on the first feed pipeline 31 near the medium feed port of the coal slime heavy medium cyclone 4 to perform real-time detection and adjustment of the pressure of the heavy medium suspension entering the cylinder of the coal slime heavy medium cyclone 4 (in the embodiment of the present application, the heavy medium suspension entering the coal slime heavy medium cyclone 4 through the first feed pipeline 31 is represented by the first heavy medium suspension); a second pressure transmitter 324 is provided on the second feed pipeline 32 near the rising medium feed port of the heavy medium interference bed separator to perform real-time detection and adjustment of the pressure of the heavy medium suspension entering the heavy medium interference bed separator (in the embodiment of the present application, the heavy medium suspension entering the heavy medium interference bed separator 5 through the second feed pipeline 32 is represented by the second heavy medium suspension).

[0055] <Heavy medium separation subsystem>

[0056] like Figure 2 As shown, the separation system forms a two-stage heavy medium separation structure through a cascaded coal slime heavy medium cyclone 4 and a heavy medium interference bed separator 5, which can efficiently and finely separate the coarse coal slime. The separated slurry enters the clean coal extraction subsystem and the tail coal extraction subsystem according to its coal content.

[0057] Among them, the medium feed port of the coal slime heavy medium cyclone 4 receives the heavy medium suspension from the qualified medium barrel 1 through the first feed pipeline 31 and rotates at high speed in the cylinder. A coal slime feeding funnel is provided on the upper part of the coal slime heavy medium cyclone 4. The selected coarse coal slime in its original state relies on its own gravity to enter the coal slime heavy medium cyclone 4 in a pressureless manner through the coal slime feeding funnel, and is efficiently sorted under the action of centrifugal force. The slurry containing clean coal components is discharged through its overflow port into the clean coal extraction subsystem, and the high-density tail coal slurry containing medium coal and gangue components is discharged through the bottom flow port into the heavy medium interference bed separator 5.

[0058] The rising medium inlet of the heavy medium interference bed separator 5 receives the heavy medium suspension from the qualified medium barrel 1 through the second feed pipeline 32. Under the action of the interference bed, the slurry entering from the bottom flow port of the coal slime heavy medium cyclone 4 is further sorted according to the density difference. The slurry with lower density enters the clean coal extraction subsystem through the overflow port, and the slurry with higher density enters the tail coal extraction subsystem through the bottom flow port.

[0059] Compared with the traditional coal slime heavy medium cyclone separation process, this method of using the same qualified medium barrel to provide feed for two-stage heavy medium separation equipment omits equipment such as mixing barrels and mixing pumps for uniformly mixing the incoming coal slime, reduces the number of equipment and operating energy consumption, and avoids problems such as over-crushing that are prone to occur during mixing in mixing barrels and conveying coal slime slurry by mixing pumps in traditional processes.

[0060] Generally, compared with the coal slime heavy medium cyclone 4, the heavy medium interference bed separator 5 requires relatively lower rising medium density and concentration, that is, the density of the first heavy medium suspension is greater than the density of the second heavy medium suspension. Preferably, the ratio of the two densities is 1.1 to 1.5.

[0061] In order to adjust the density ratio of the second heavy medium suspension to the first heavy medium suspension to a suitable range, preferably, as Figure 2 As shown, a first clean water regulating valve 325 is provided at the front end of the second densitometer 323 on the second feed pipeline 32. In this way, the density of the heavy medium suspension in the qualified medium barrel 1 is first adjusted using the water replenishing valve and the medium powder replenishing device of the qualified medium barrel, and the density of the first heavy medium suspension output by the first qualified medium feed pump 21 is adjusted by the first densitometer 313 to meet the heavy medium feeding requirements of the coarse coal slime heavy medium cyclone 4. On this basis, the amount of added clean water is adjusted by the first clean water regulating valve 325, and the density of the second heavy medium suspension obtained after dilution is detected by the second densitometer 323, so as to adjust the density and concentration ratio of the second heavy medium suspension to the first heavy medium suspension to an appropriate range.

[0062] <Clean coal extraction subsystem>

[0063] like Figure 2 As shown, in this embodiment, the clean coal extraction subsystem includes a cascade of clean coal de-intermediation laminated high-frequency fine screen 61 , a clean coal magnetic separator 62 , a clean coal laminated high-frequency fine screen 63 and a clean coal slime centrifugal dewatering machine 64 .

[0064] Among them, the overflow ports of the coal slime heavy medium cyclone 4 and the heavy medium interference bed separator 5 are both connected to the clean coal de-medium laminated high-frequency fine screen, and their overflow products are combined and enter the clean coal de-medium laminated high-frequency fine screen 61 for de-medium treatment. The undersize of the clean coal de-medium laminated high-frequency fine screen 61 is returned to the qualified medium barrel 1, and the oversize is diluted with clean water (preferably, the concentration of the diluted oversize is 15-25%) and then enters the clean coal magnetic separator 62 for medium recovery operation; the concentrate product recovered by the clean coal magnetic separator 62 is returned to the qualified medium barrel 1, and the tailings product enters the clean coal laminated high-frequency fine screen 63 for dehydration and desliming treatment; the oversize of the clean coal laminated high-frequency fine screen 63 enters the clean coal slime centrifugal dehydrator 64 for final moisture control, and its dehydration product is a qualified clean coal product, and its centrifugal liquid enters the flotation machine.

[0065] Since the slurry entering the clean coal de-intermediation laminated high-frequency fine screen comes from the overflow of the coal slime heavy medium cyclone, the mud content is high and the clean coal particle size is fine, the smaller-sized coal slime content in the screen material may be high. The above-mentioned screen material directly enters the qualified medium barrel 1, which may lead to an increase in the coal slime content in the heavy medium suspension. For this reason, in some preferred embodiments, the clean coal extraction subsystem also includes a diverter valve 65, which is arranged on the pipeline for the screen material of the clean coal de-intermediation laminated high-frequency fine screen 61 to return to the qualified medium barrel 1. When the magnetic material content in the screen material of the clean coal de-intermediation laminated high-frequency fine screen 61 is too low, the diverter valve 65 can be adjusted to reduce the flow rate returning to the qualified medium barrel 1 here, and it can be diverted to the clean coal magnetic separator 62 for medium recovery to reduce the coal slime content in the heavy medium suspension.

[0066] <Tail coal extraction subsystem>

[0067] like Figure 2 As shown, in this embodiment, the tail coal extraction subsystem includes a cascaded tail coal de-intermediation laminated high-frequency fine screen 71, a tail coal magnetic separator 72, a tail coal laminated high-frequency fine screen 73 and a tail coal slime centrifugal dewatering machine 74.

[0068] Among them, the bottom flow port of the heavy medium interference bed separator 5 is connected to the tail coal de-medium laminated high-frequency fine screen 71, and its bottom flow product enters the tail coal de-medium laminated high-frequency fine screen 71 for de-medium treatment. The undersize material of the tail coal de-medium laminated high-frequency fine screen 71 returns to the qualified medium barrel, and the oversize material (preferably, the concentration of the diluted oversize material is 15-25%) enters the tail coal magnetic separator 72; the concentrate product of the tail coal magnetic separator 72 returns to the qualified medium barrel 1, and the tailings product enters the tail coal laminated high-frequency fine screen 73; the oversize material of the tail coal laminated high-frequency fine screen 73 enters the tail coal slime centrifugal dehydrator 74, and the undersize material enters the concentrator; the dehydration product of the tail coal slime centrifugal dehydrator 74 is tail coal, and the centrifugal liquid enters the concentrator.

[0069] The two-stage heavy medium separation method for coarse coal slime provided in this embodiment optimizes the cascade structure and feeding structure of the separation device of the existing two-stage separation system for coarse coal slime, and adopts two-stage heavy medium separation devices with different medium densities to separate the coal slime. Compared with the existing solution of using the hydrocyclone as the first-stage separation device, it can effectively improve the recovery rate of the clean coal product; at the same time, only one qualified medium barrel is used to provide heavy medium suspension for the two-stage heavy medium separation devices at the same time, and the qualified medium suspension is fed into the coal slime heavy medium cyclone and the heavy medium cyclone respectively by a qualified medium pump in a pressurized manner. In the medium interference bed separator, the selected coal slime adopts a pressure-free feeding method and enters the coal slime heavy medium cyclone by its own gravity. Therefore, there is no need to set up a mixing barrel to mix the qualified medium suspension with the selected coal slime, which effectively reduces the number of equipment and operating energy consumption. In addition, the medium components obtained after de-mediation and magnetic separation of the products of the two-stage heavy medium separation device are returned to the qualified medium barrel, forming a feedback adjustment closed loop for the concentration of the heavy medium suspension, which can quickly and accurately adjust the density of the heavy medium suspension entering the two-stage heavy medium separation device according to the changes in the composition of the selected coal slime.

[0070] Second embodiment

[0071] Figure 3 This is a framework schematic diagram of a coarse coal slime two-stage heavy medium separation system provided according to the second embodiment of the present application. The difference between this embodiment and the first embodiment is that, in addition to the first qualified medium feed pump 21, the heavy medium feeding subsystem also includes a second qualified medium feed pump 22. The first feeding pipeline 31 and the second feeding pipeline 32 are no longer connected to the outlet of the first qualified medium feed pump 21 as shown in the first embodiment. Instead, the first feeding pipeline 31 is connected to the outlet of the first qualified medium feed pump 21, and the second feeding pipeline 32 is connected to the outlet of the second qualified medium feed pump 22. The qualified medium suspension is pumped into the heavy medium interference bed separator 5 through the second qualified medium feed pump 22.

[0072] Preferably, if Figure 3As shown, the connection position of the second qualified medium feeding pump 22 and the qualified medium barrel 1 is higher than the connection position of the first qualified medium feeding pump 21 and the qualified medium barrel 1, and there is a height difference H between the two.

[0073] The reason for separately setting up a second qualified medium feed pump 22 for the second feed pipeline 32 and positioning it higher than the first qualified medium feed pump 21 is that: as analyzed above, the density of the second heavy medium suspension entering the heavy medium interference bed separator 5 generally needs to be smaller than the density of the first heavy medium suspension entering the coal slime heavy medium cyclone 4. Since the density of the magnetic medium in the heavy medium suspension is relatively large and has an obvious tendency to fall under gravity, the medium suspension in the qualified medium barrel 1 often shows density stratification. The density of the suspension located at the lower part of the qualified medium barrel 1 is naturally greater than the density of the suspension located at the upper part. By utilizing this phenomenon, by raising the position of the second qualified medium feed pump 22, the suspension pumped out by it can be closer to the density required by the heavy medium interference bed separator 5 than the suspension pumped out by the first qualified medium feed pump 21, and the operating requirements can be met without excessive dilution through the first clean water regulating valve 325.

[0074] Third embodiment

[0075] Figure 4 FIG. 1 shows a schematic diagram of a framework of a two-stage heavy medium separation system for coarse coal slime according to a third embodiment of the present application. Figure 4 As shown, in this embodiment, the heavy medium feeding subsystem includes, in addition to the first feeding pipeline 31 and the second feeding pipeline 32, a third feeding pipeline 33. The third feeding pipeline 33 is used to pre-swirl and pre-wet the incoming coal slime at the coal slime feeding funnel of the coal slime heavy medium cyclone 4, thereby ensuring more efficient sorting of the coal slime after entering the cylinder.

[0076] Among them, a third flow regulating valve 331 is provided on the third feed pipeline 33, which is used to adjust the flow of the heavy medium suspension for pre-spinning and pre-wetting treatment of the coal slime. In addition, in some preferred embodiments, a third magnetic content meter 332, a third density meter 333 and a third pressure transmitter 334 are also provided on the third feed pipeline 33. The setting method and working method of the above devices are the same as or similar to the corresponding devices on the first feed pipeline 31 and the second feed pipeline 32, and are not repeated here.

[0077] The density of the heavy medium suspension (referred to as the third heavy medium suspension in this embodiment) entering the coal slime feeding funnel for pre-spinning and pre-wetting the coal slime needs to be adjusted according to the properties of the selected coal slime. In some preferred embodiments, the density of the third heavy medium suspension can be the same as the density of the first heavy medium suspension, or, in other preferred embodiments, the density of the third heavy medium suspension can be adjusted to be slightly smaller than the density of the first heavy medium suspension.

[0078] Figure 4 The first feed pipeline 31, the second feed pipeline 32 and the third feed pipeline 33 are all connected to the first qualified medium feed pump 21. In some preferred embodiments, in order to adjust the density of the third heavy medium suspension, a second clean water regulating valve (not shown in the figure) can also be set at the front end of the third density meter 333 on the third feed pipeline 33; in addition, as shown in the second embodiment, a second qualified medium feed pump 22 can be added to provide feed for the second feed pipeline 32 and the third feed pipeline 33, and then the density can be adjusted in combination with the second clean water regulating valve; in other preferred embodiments, a third qualified medium feed pump (not shown in the figure) can be further added, and its height relative to the qualified medium barrel 1 can be set according to the density required to be achieved by the third heavy medium suspension, so as to adjust the density of the third heavy medium suspension more efficiently and water-savingly.

[0079] Figure 5 The specific structural diagram of the coal slime heavy medium cyclone 4 in this embodiment is shown in FIG. Figure 5 As shown, the coal slime heavy medium cyclone 4 includes a cylinder 41 , a medium feed port 42 , an overflow port 43 , an underflow port 44 , and a coal slime feed funnel 45 .

[0080] Among them, the coal slime feeding funnel 45 is connected to the cylinder 41 through the feeding pipe 46, so that the selected coal slime enters the cylinder 41 under the action of gravity. The end of the third feeding pipeline 33 is connected to the pre-rotation wetting tube 335, which passes through and enters the coal slime feeding funnel 45 at a tangential angle, forming a high-speed rotating centrifugal force field in the coal slime feeding funnel 45. After the selected coal slime enters, it can be quickly mixed with the high-speed rotating third medium suspension to obtain the rotation speed required for effective sorting, thereby achieving the purpose of efficient sorting.

[0081] Furthermore, if Figure 5 As shown, the cross-section of the medium feed port 42 is rectangular, and the medium enters the cylinder 41 at one side of the lower part of the coal slime heavy medium cyclone 4 by a tangential or involute feeding method. The overflow pipe connected to the overflow port 43 is vertically inserted into the central cavity at the lower part of the cylinder 41. The underflow port 44 is arranged on one side of the upper part of the cyclone. Its size can be adjusted according to the properties of the processed coal slime and production index requirements.

[0082] In some preferred embodiments, the ratio of the length to the diameter of the cylinder 41 is in the range of 3.5 to 4.5, the ratio of the diameter of the medium feed port 42 to the diameter of the cylinder 41 is in the range of 0.20 to 0.25, the ratio of the diameter of the overflow port 43 to the diameter of the cylinder 41 is in the range of 0.30-0.40, and the ratio of the diameter of the underflow port 44 to the diameter of the cylinder 41 is in the range of 0.25 to 0.30. The size of the length-to-diameter ratio determines the sorting time of the incoming coal slime in the cyclone. The sizes of the feed port, overflow port, and underflow port have a significant impact on the sorting index and can be customized according to the properties of the incoming coal slime and production index requirements.

[0083] In addition, if Figure 5 As shown, the cylinder 41 is fixed obliquely by a bracket 47, and the coal slime feeding direction of the coal slime feeding funnel 45 is kept vertical.

[0084] Fourth embodiment

[0085] The fourth embodiment of the present application provides a two-stage heavy medium separation method for coarse coal slime, which can be implemented by the separation system provided in the first to third embodiments. Specifically, Figure 6 As shown, the sorting method includes the following steps:

[0086] A1: The qualified medium suspension in the qualified medium barrel passes through the qualified medium feed pump and the first feed pipeline and enters the medium feed port of the coal slime heavy medium cyclone at a first flow rate, a first pressure, and a first density. The selected coal slime flows by its own gravity through the coal slime feed funnel and enters the coal slime heavy medium cyclone for primary separation.

[0087] A2: The underflow product of the coal slime heavy medium cyclone enters the heavy medium interference bed separator for secondary separation. The qualified medium suspension in the qualified medium barrel passes through the qualified medium feed pump and the second feed pipeline and enters the rising medium inlet of the heavy medium interference bed separator at the second flow rate, second pressure and second density.

[0088] A3. The overflow product from the coal slime heavy medium cyclone and the overflow product from the heavy medium interference bed separator are combined and fed into the clean coal de-intermediation laminated high-frequency fine screen for de-intermediation treatment. The undersize material from the clean coal de-intermediation laminated high-frequency fine screen is returned to the qualified medium barrel. The oversize material from the clean coal de-intermediation laminated high-frequency fine screen is diluted with clean water and fed into the clean coal magnetic separator for medium recovery. The concentrate from the clean coal magnetic separator is returned to the qualified medium barrel. The tailings from the clean coal magnetic separator are fed into the clean coal laminated high-frequency fine screen for dehydration and desliming. The oversize material from the clean coal laminated high-frequency fine screen is fed into the clean coal slime centrifugal dehydrator for final moisture control. The dehydrated product from the clean coal slime centrifugal dehydrator becomes qualified clean coal. The undersize material from the clean coal laminated high-frequency fine screen and the centrifugal liquid from the clean coal slime centrifugal dehydrator are fed into the flotation machine.

[0089] A4. The underflow product of the heavy medium interference bed separator enters the tailings de-mediumizing laminated high-frequency fine screen for de-mediumizing treatment. The undersize material of the tailings de-mediumizing laminated high-frequency fine screen is returned to the qualified medium barrel. The oversize material of the tailings de-mediumizing laminated high-frequency fine screen is diluted with clean water and enters the tailings magnetic separator for medium recovery operation. The concentrate of the tailings magnetic separator returns to the qualified medium barrel. The tailings of the tailings magnetic separator enter the tailings laminated high-frequency fine screen for dehydration and desliming treatment. The oversize material of the tailings laminated high-frequency fine screen enters the tailings slime centrifugal dehydrator for final moisture control and becomes the tailings product. The undersize material of the tailings laminated high-frequency fine screen and the centrifugal liquid of the tailings slime centrifugal dehydrator enter the concentrator.

[0090] In some preferred embodiments, the coarse coal slime two-stage heavy medium separation method further comprises the following steps:

[0091] A11, the qualified medium suspension in the qualified medium barrel passes through the qualified medium feed pump and the third feed pipeline, and enters the coal slime feed funnel of the coal slime heavy medium cyclone along the tangential direction according to the flow rate, the third pressure and the third density.

[0092] The above is a detailed introduction to the specific implementation methods of the present application. For those skilled in the art, several improvements and modifications can be made to the present application without departing from the principles of the present application. These improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A coarse coal slime two-stage heavy medium separation system, comprising a heavy medium feeding subsystem, a heavy medium separation subsystem, a clean coal extraction subsystem, and a tail coal extraction subsystem, characterized in that: The heavy medium separation subsystem includes a coal slime heavy medium cyclone and a heavy medium interference bed separator. A coal slime feeding funnel is provided on the upper part of the coal slime heavy medium cyclone. The overflow port is connected to the clean coal extraction subsystem, and the underflow port is connected to the feeding port of the heavy medium interference bed separator. The overflow port and underflow port of the heavy medium interference bed separator are connected to the clean coal extraction subsystem and the tail coal extraction subsystem respectively. The heavy medium feeding subsystem includes a qualified medium barrel, a first feeding pipeline, a first flow regulating valve, a second feeding pipeline, a second flow regulating valve and at least one qualified medium feeding pump, wherein the inlet of the qualified medium feeding pump is connected to the qualified medium barrel, and the outlet is connected to the medium feeding port of the coal slime heavy medium cyclone and the rising medium inlet of the heavy medium interference bed separator through the first feeding pipeline and the second feeding pipeline respectively, the first flow regulating valve and the second flow regulating valve are respectively arranged on the first feeding pipeline and the second feeding pipeline, and a qualified medium barrel is used to simultaneously provide heavy medium suspension for the two-stage heavy medium separation device, and the qualified medium suspension is respectively fed into the coal slime heavy medium cyclone and the heavy medium interference bed separator by pressurized conveying through the qualified medium pump; The density ratio of the first heavy medium suspension entering the coal slime heavy medium cyclone through the first feed pipeline to the second heavy medium suspension entering the heavy medium interference bed separator through the second feed pipeline is 1.1 to 1.5; There are two qualified medium feeding pumps, namely a first qualified medium feeding pump and a second qualified medium feeding pump; Among them, the outlet of the first qualified medium feed pump is connected to the first feed pipeline, the outlet of the second qualified medium feed pump is connected to the second feed pipeline, and the connection position of the second qualified medium feed pump and the qualified medium barrel is higher than the connection position of the first qualified medium feed pump and the qualified medium barrel.

2. The coarse coal slime two-stage heavy medium separation system according to claim 1, characterized in that: The first feed pipeline is further provided with a first density meter, and the second feed pipeline is further provided with a second density meter and a first clean water regulating valve; The first clean water regulating valve is located at the front end of the second densitometer on the second feed pipeline.

3. The coarse coal slime two-stage heavy medium separation system according to claim 1, characterized in that: The heavy medium feeding subsystem further includes a third feeding pipeline, a pre-swirl wetting pipe and a third flow regulating valve; One end of the third feed pipeline is connected to the outlet of the qualified medium feed pump, and the other end is connected to the pre-swirl wetting pipe. The third flow regulating valve is arranged on the third feed pipeline, and the pre-swirl wetting pipe passes through and enters the interior of the coal slime feed funnel.

4. The coarse coal slime two-stage heavy medium separation system according to claim 3, characterized in that: The density of the third heavy medium suspension entering the coal slime feeding funnel through the pre-swirl wetting pipe is not greater than the density of the first heavy medium suspension.

5. The coarse coal slime two-stage heavy medium separation system according to claim 1, characterized in that: The top of the qualified medium barrel is provided with a water replenishing valve and a medium powder replenishing device, and a liquid level meter is provided inside.

6. The coarse coal slime two-stage heavy medium separation system according to claim 1, characterized in that: The clean coal extraction subsystem includes a clean coal de-intermediation laminated high-frequency fine screen, a clean coal magnetic separator, a clean coal laminated high-frequency fine screen, and a clean coal slime centrifugal dehydrator; The overflow ports of the coal slime heavy medium cyclone and the heavy medium interference bed separator are connected to the clean coal de-intermediation laminated high-frequency fine screen, and the undersize of the clean coal de-intermediation laminated high-frequency fine screen returns to the qualified medium barrel, and the oversize enters the clean coal magnetic separator; The concentrate product of the clean coal magnetic separator returns to the qualified medium barrel, and the tailings product enters the clean coal laminated high-frequency fine screen; The oversize material of the clean coal laminated high-frequency fine screen enters the clean coal slime centrifugal dehydrator, and the undersize material enters the flotation machine; The dehydration product of the clean coal slime centrifugal dehydrator is clean coal, and the centrifugal liquid enters the flotation machine.

7. The coarse coal slime two-stage heavy medium separation system according to claim 6, characterized in that: The clean coal extraction subsystem further comprises a diverter valve for diverting the undersize of the clean coal de-intermediation laminated high-frequency fine screen to the clean coal magnetic separator.

8. The coarse coal slime two-stage heavy medium separation system according to claim 1, characterized in that: The tail coal extraction subsystem includes a tail coal de-intermediation laminated high-frequency fine screen, a tail coal magnetic separator, a tail coal laminated high-frequency fine screen, and a tail coal slime centrifugal dewatering machine; The bottom flow port of the heavy medium interference bed separator is connected to the tail coal de-intermediation laminated high-frequency fine screen, and the undersize of the tail coal de-intermediation laminated high-frequency fine screen returns to the qualified medium barrel, and the oversize enters the tail coal magnetic separator; The concentrate product of the tailings magnetic separator returns to the qualified medium barrel, and the tailings product enters the tailings laminated high-frequency fine screen; The oversize of the tail coal stacked high-frequency fine screen enters the tail coal slime centrifugal dehydrator, and the undersize enters the thickener; The dehydration product of the tail coal slime centrifugal dehydrator is tail coal, and the centrifugal liquid enters the concentrator.

9. A two-stage heavy medium separation method for coarse coal slime, characterized in that: The following steps are involved: A1: The qualified medium suspension in the qualified medium barrel passes through the qualified medium feed pump and the first feed pipeline and enters the medium feed port of the coal slime heavy medium cyclone at a first flow rate, a first pressure, and a first density. The selected coal slime flows by its own gravity through the coal slime feed funnel and enters the coal slime heavy medium cyclone for primary separation. A2: The underflow product of the coal slime heavy medium cyclone enters the heavy medium interference bed separator for secondary separation. The qualified medium suspension in the qualified medium barrel passes through the qualified medium feed pump and the second feed pipeline and enters the rising medium inlet of the heavy medium interference bed separator at the second flow rate, second pressure and second density. A3. The overflow product from the coal slime heavy medium cyclone and the overflow product from the heavy medium interference bed separator are combined and fed into the clean coal de-intermediation laminated high-frequency fine screen for de-intermediation treatment. The undersize material from the clean coal de-intermediation laminated high-frequency fine screen is returned to the qualified medium barrel. The oversize material from the clean coal de-intermediation laminated high-frequency fine screen is diluted with clean water and fed into the clean coal magnetic separator for medium recovery. The concentrate from the clean coal magnetic separator is returned to the qualified medium barrel. The tailings from the clean coal magnetic separator are fed into the clean coal laminated high-frequency fine screen for dehydration and desliming. The oversize material from the clean coal laminated high-frequency fine screen is fed into the clean coal slime centrifugal dehydrator for final moisture control. The dehydrated product from the clean coal slime centrifugal dehydrator becomes qualified clean coal. The undersize material from the clean coal laminated high-frequency fine screen and the centrifugal liquid from the clean coal slime centrifugal dehydrator are fed into the flotation machine. A4. The underflow product of the heavy medium interference bed separator enters the tailings de-mediumizing laminated high-frequency fine screen for de-mediumizing treatment. The undersize material of the tailings de-mediumizing laminated high-frequency fine screen is returned to the qualified medium barrel. The oversize material of the tailings de-mediumizing laminated high-frequency fine screen is diluted with clean water and enters the tailings magnetic separator for medium recovery operation. The concentrate of the tailings magnetic separator returns to the qualified medium barrel. The tailings of the tailings magnetic separator enter the tailings laminated high-frequency fine screen for dehydration and desliming treatment. The oversize material of the tailings laminated high-frequency fine screen enters the tailings slime centrifugal dehydrator for final moisture control and becomes the tailings product. The undersize material of the tailings laminated high-frequency fine screen and the centrifugal liquid of the tailings slime centrifugal dehydrator enter the concentrator.

10. The two-stage heavy medium separation method for coarse coal slime according to claim 9, characterized in that: The following steps are also included: A11, the qualified medium suspension in the qualified medium barrel passes through the qualified medium feed pump and the third feed pipeline, and enters the coal slime feed funnel of the coal slime heavy medium cyclone along the tangential direction according to the flow rate, the third pressure and the third density.

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