Underground gangue discharge method for softening coal

Abstract

The application provides a gangue discharging method for easy-mudding coal in a mine, which comprises the following steps: performing wind power de-dusting on raw coal in a mine working face to obtain lump coal and powder coal; performing screening on the lump coal to obtain size-grade coal; performing separation on the size-grade coal to obtain coarse clean coal and gangue; lifting the coarse clean coal to the ground and backfilling the gangue in the mine; and performing heavy medium shallow groove separation on the coarse clean coal. The technical scheme of the application effectively solves the problem that a large amount of coal slurry is generated during gangue discharging in the related art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mineral processing, in particular to an underground gangue discharging method for easily argillized coal. BACKGROUND

[0002] With the acceleration of the process of coal mining mechanization, the amount of fine coal increases significantly, the quality of raw coal is continuously deteriorated, and the processing of coal becomes more complex. The mainstream process of the coal separation industry is still the wet coal separation process, and the addition of too much fine coal and argillaceous minerals will make the washing water quality worse.

[0003] Thin coal seams have many faults, more complex mining environment, narrower mining face, and higher risks in the mining process. The combined mining technology provides a new idea for the development and utilization of close and thin coal seams, and the combined mining of coal seams close to each other and the gangue layer in between can solve the problem of resource waste in mining single coal seam to some extent. However, a large amount of easily argillized gangue will be produced during the combined mining process, which will have a serious impact on subsequent coal separation if not pretreated: first, the argillized gangue will cover the surface of the clean coal, raising the ash content of the clean coal; second, a large amount of coal slime entering the separation system will increase the load of coal slime water treatment and worsen the closed-circuit environment of washing water, which is not conducive to flotation operation.

[0004] In the related art, the focus of underground gangue discharging is on lump coal gangue discharging, and the methods mainly include heavy medium shallow slot gangue discharging process and dynamic sieve jigging gangue discharging process. The heavy medium shallow slot gangue discharging process and the dynamic sieve jigging gangue discharging process both belong to underground wet gangue discharging process, and have the advantages of wide feeding particle size and large processing capacity, but there are still some problems in the application process due to the complexity of the system: ① the easily argillized gangue will produce a large amount of difficult-to-treat coal slime water when it comes into contact with water; ② the wet process will increase the moisture content of the product, directly affecting the calorific value and pricing quantity of the coal; ③ excessive gangue entering the wet separation equipment will affect its processing capacity, and even cause shutdown accidents. SUMMARY

[0005] The main purpose of the present application is to provide an underground gangue discharging method for easily argillized coal to solve the problem of a large amount of coal slime water produced during gangue discharging in the related art.

[0006] In order to achieve the above-mentioned purpose, the present application provides an underground gangue discharging method for easily argillized coal, which comprises: performing wind power de-dusting on the raw coal of the mine working face to obtain lump coal and fine coal; screening the lump coal to obtain particle size coal; separating the particle size coal to obtain coarse clean coal and gangue; lifting the coarse clean coal and backfilling the gangue underground; and performing heavy medium shallow slot separation on the coarse clean coal.

[0007] Further, the step of screening the lump coal to obtain particle size coal comprises: screening the lump coal through a double-layer tension screen to obtain first particle size coal, second particle size coal and third particle size coal in descending order of particle size.

[0008] Further, the step of sorting the particle size coal to obtain the coarse clean coal and the gangue includes: sorting the first particle size coal by photoelectric sorting to obtain the first coarse clean coal and the first gangue; sorting the second particle size coal by cascade fluidization sorting to obtain the second coarse clean coal and the second gangue; sorting the third particle size coal by air shaking table to obtain the third coarse clean coal and the third gangue.

[0009] Further, the step of hoisting the coarse clean coal and backfilling the gangue underground includes: hoisting the first coarse clean coal, the second coarse clean coal and the third coarse clean coal; backfilling the first gangue, the second gangue and the third gangue underground.

[0010] Further, the size range of the particle size of the wind power de-dusting is between 0.5mm and 2mm.

[0011] Further, the size range of the first screening particle size of the double-layer tension screen is between 40mm and 60mm, the size range of the second screening particle size of the double-layer tension screen is between 5mm and 7mm, and the size range of the third screening particle size of the double-layer tension screen is less than 6mm.

[0012] Further, the step of hoisting the first coarse clean coal, the second coarse clean coal and the third coarse clean coal includes: hoisting the first coarse clean coal and the second coarse clean coal after being combined; and hoisting the third coarse clean coal separately.

[0013] Further, the step of sorting the coarse clean coal by the heavy medium shallow tank includes: sorting the first coarse clean coal and the second coarse clean coal by the heavy medium shallow tank.

[0014] Further, the equipment of the photoelectric sorting is an X-ray photoelectric sorting machine.

[0015] Further, the equipment of the cascade fluidization sorting is a cascade fluidization sorting machine.

[0016] The technical scheme of the present application is applied to firstly perform wind dedusting on the raw coal in the working face in the mine to obtain lump coal and powder coal, screen the obtained lump coal to obtain size coal, separate the obtained size coal to obtain clean coal and gangue, lift the clean coal to the surface, and backfill the gangue in the mine. Finally, the lifted clean coal is separated again by a heavy medium shallow tank. Through the above arrangement, the wind dedusting is performed in the mine, which can avoid the spread of the generated dust in the air. The separation of the size coal can effectively separate the clean coal and the gangue, and then the clean coal and the gangue can be separately treated. The backfilling of the gangue in the mine can effectively improve the production efficiency and avoid the lifting of the gangue to the surface and then the backfilling of the gangue in the mine. Finally, the lifted clean coal is separated again by a heavy medium shallow tank, and coal with different particle sizes can be obtained. In the above steps, the lifting of the clean coal to the surface is completed in the mine, and the gangue is discharged by a dry method without water washing, which can effectively avoid the generation of coal slurry water, and the above steps can improve the efficiency of the gangue discharge and the separation. Therefore, the technical scheme of the present application effectively solves the problem of the generation of a large amount of coal slurry water in the related art. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which form a part of this specification, are included to provide a further understanding of the application, and are incorporated by reference herein. The embodiments depicted within the drawings are in no way limiting of the present application and may

[0018] Figure 1 An operation step schematic diagram of an embodiment of the method for discharging gangue of softening coal in a mine according to the present application is shown.

[0019] Figure 2 A flowchart of the method for discharging gangue of softening coal in a mine according to the present application is shown. Figure 1 A flowchart of the method for discharging gangue of softening coal in a mine according to the present application is shown. DETAILED DESCRIPTION

[0020] The technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0021] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0022] The relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the examples are not intended to limit the scope of the application unless otherwise specifically stated. It is to be understood that the drawings are not necessarily to scale as the dimensions of the parts shown are for the purpose of illustration and description only. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as if the techniques, methods, and apparatus were discussed in detail herein. In all examples shown and discussed herein, any specific values are to be interpreted as illustrative only and not as a limitation. Thus, other examples of the example embodiments can have different values. It is noted that like numbers and letters on the figures identify like parts throughout the several views, and thus, once an item is defined in one figure, it is not necessary to discuss it further in connection with other figures.

[0023] Underground gangue discharge is a sustainable development technology that is conducive to energy saving and consumption reduction and improving raw coal quality. At present, the focus of underground gangue discharge is on lump coal gangue discharge, and the main methods include heavy medium shallow trough gangue discharge process, dynamic sieve jigging gangue discharge process, and X-ray intelligent dry separation process. The heavy medium shallow trough gangue discharge process and the dynamic sieve jigging gangue discharge process both belong to underground wet gangue discharge process, and have the advantages of wide feed size and large processing capacity, but at present, due to the complexity of the system, there are still some problems in the application process: ① The mudified gangue will produce a large amount of difficult-to-treat coal slurry when it meets water; ② The wet process will increase the moisture of the product, directly affecting the calorific value and the pricing quantity of the coal; ③ Excessive gangue entering the wet separation equipment will affect its processing capacity, and even cause shutdown accidents. The X-ray separator can overcome the above defects, and has the advantages of wide application range and no increase in clean coal moisture, but its single-channel capacity is low, and the processing capacity per unit time is small. The above processes have been maturely applied in various coal mines, but they have poor adaptability to the joint mining of mudified gangue with high content. In order to achieve the purpose of reducing coal slime, the fine coal gangue discharge technology emerges as the times require. For mudified gangue, it is far from enough to treat coal slime in a single separation link, and it is necessary to consider the treatment of coal slime and the reduction of coal slime at the level of the process system.

[0024] The underground gangue discharging method of the easily-mudified coal is a dry gangue discharging process suitable for the easily-mudified coal with high content of gangue. In the specific production, if the pre-gangue discharging operation is not performed, the easily-mudified gangue mined will enter the dense medium system, thereby generating a large amount of secondary coal slime, affecting the separation precision, and deteriorating the closed water circuit.

[0025] To solve the above technical problems, as shown in Figure 1 and Figure 2 In the embodiment, the underground gangue discharging method of the easily-mudified coal comprises the following steps: step S10, performing the wind power de-dusting on the raw coal of the working face of the mine to obtain lump coal and fine coal; step S20, performing the screening on the lump coal to obtain size coal; step S30, performing the separation on the size coal to obtain coarse clean coal and gangue; step S40, lifting the coarse clean coal and backfilling the gangue underground; and step S50, performing the dense medium shallow tank separation on the coarse clean coal.

[0026] By applying the technical solution of the embodiment, the wind power de-dusting is first performed on the raw coal of the working face in the mine to obtain lump coal and fine coal, and the obtained lump coal is screened to obtain size coal. The obtained size coal is separated to obtain coarse clean coal and gangue. The coarse clean coal is lifted, and the gangue is backfilled underground. Finally, the lifted coarse clean coal is re-separated by the dense medium shallow tank. Through the above setting, the wind power de-dusting is processed underground, which can avoid the diffusion of the generated dust in the air. The separation of the size coal can effectively separate the coarse clean coal and the gangue, and then the two can be separately processed. The backfilling of the gangue underground can effectively improve the production efficiency and avoid the lifting of the gangue underground and then the backfilling underground. Finally, the lifted coarse clean coal is re-separated by the dense medium shallow tank, and different particle size coals can be obtained. In the above steps, the lifting of the coarse clean coal is completed underground, and no water washing is required, that is, the dry gangue discharging is performed, which can effectively avoid the generation of coal slime water, and the above steps can improve the efficiency of the gangue discharging and separation. Therefore, the technical solution of the embodiment effectively solves the problem of the generation of a large amount of coal slime water during the gangue discharging in the related art.

[0027] It should be noted that the above wind power de-dusting is performed by a wind power de-dusting device. The wind power de-dusting device is a wind power separation structure with a grading function, which is obtained by modifying the material guide chute of the transportation belt conveyor as needed. The de-dusting of the fine particle coal can avoid the adverse effect on the X-ray photoelectric separator and the cascade fluidized separator.

[0028] The technical scheme of the embodiment removes fine particle pulverized coal by air force to make it enter the fine particle level part, effectively separates the pulverized coal by the multi-layer aerated air force shaking table, can avoid the interference of the pulverized coal on the gangue removal and separation operation of the lump coal and reduce the amount of coal slime brought into the main separation system, and achieves the purpose of reducing the amount of coal slime from the source. In addition, the pre-separation of the pulverized coal and the feeding of the multi-layer aerated air force shaking table can realize fine particle level gangue removal; the combined process of the X-ray photoelectric separator and the cascade fluidized separator can realize full particle level gangue removal of raw coal. The process considers the limited underground space, uses full dry method for gangue removal, greatly simplifies the process flow, facilitates the connection with the coal mining production line, has small equipment investment, is easy to be intelligentized, meets the needs of intelligentized mines, and meets the needs of green mines.

[0029] As shown in Figure 1 and Figure 2 In the embodiment, the step of screening the lump coal to obtain the particle level coal includes: screening the lump coal by the double-layer tension screen to obtain the first particle level coal, the second particle level coal and the third particle level coal with particle sizes from large to small. Through the above steps, the particle level coal can be effectively screened to obtain multiple grades of particle level coal, i.e. the first particle level coal, the second particle level coal and the third particle level coal. After such screening, it is more convenient for subsequent separation and further processing.

[0030] As shown in Figure 1 and Figure 2As shown in the figure, in the embodiment, the step of sorting the coal of different particle sizes to obtain the coarse clean coal and the gangue includes: sorting the first coal of a particle size by photoelectric sorting to obtain first coarse clean coal and first gangue; sorting the second coal of a particle size by cascade fluidization sorting to obtain second coarse clean coal and second gangue; and sorting the third coal of a particle size by a pneumatic shaking table to obtain third coarse clean coal and third gangue. The photoelectric sorting machine is suitable for an underground working environment and uses intrinsically safe electrical components. The height of the equipment can be reduced according to the internal structure to adapt to the limitations of the chamber. The product is directly conveyed to the product belt conveyor from the material collecting hopper and the feeding chute below the equipment, and no wet process is involved in the process, which can effectively reduce the generation of secondary coal slime and reduce the equipment failure rate. The cascade fluidization sorting equipment is modular in design and includes a homogenization feeding module, a power module, a sorting module, a discharge module, and a dust removal module, and has the characteristics of simple structure and quick loading and unloading. The light product after sorting passes through the overflow weir to become coarse clean coal and falls onto the product belt conveyor, and the heavy product is conveyed to the gangue belt. The pneumatic shaking table is composed of a perforated bed surface, a wind distribution system with multiple air chambers and valves, and a vibration mechanism. The bed surface with grooves is inclined in the longitudinal and transverse directions. Under the combined action of vibration and fluidization, the fine particles on the bed surface are layered: the movement state of the material determines that the light particles quickly leave the bed surface in the transverse direction, while the heavy particles continue to move longitudinally on the bed surface to the end tailing port for discharge, and the obtained product can be directly combined into the product belt without secondary treatment. The multiple shaking tables are stacked to increase the processing capacity. Specifically, full particle size sorting can be achieved by photoelectric sorting, cascade fluidization sorting, and pneumatic shaking table, without affecting the efficiency of sorting, and ensuring that each device can efficiently and accurately sort.

[0031] As shown in the figure, Figure 1 and Figure 2 As shown in the figure, in the embodiment, the step of lifting the coarse clean coal to the surface and backfilling the gangue underground includes: lifting the first coarse clean coal, the second coarse clean coal, and the third coarse clean coal to the surface; and backfilling the first gangue, the second gangue, and the third gangue underground. The above arrangement can further combine the sorted coarse clean coal, which can effectively improve the efficiency of lifting to the surface and facilitate the subsequent process.

[0032] As shown in the figure, Figure 1 and Figure 2 As shown in the figure, in the embodiment, the classification particle size of the pneumatic dedusting is between 0.5 mm and 2 mm. The above arrangement can effectively improve the dedusting effect. Specifically, in the embodiment, the classification particle size of the pneumatic dedusting is 1 mm.

[0033] As shown in the figure, Figure 1 and Figure 2As shown, in this embodiment, the first screening particle size range of the double-layer tension screen is between 40mm and 60mm, the second screening particle size range is between 5mm and 7mm, and the third screening particle size is less than 6mm. The above settings ensure the sorting effect.

[0034] like Figure 1 and Figure 2 As shown, in this embodiment, the step of raising the first, second, and third coarse coal to the surface includes: raising the first and second coarse coal together; and raising the third coarse coal separately. This arrangement improves the efficiency of the raising process, as the larger sizes of the first and second coarse coal allow them to be combined for subsequent operations, while the smaller size of the third coarse coal necessitates separate processing.

[0035] like Figure 1 and Figure 2 As shown, in this embodiment, the step of heavy medium shallow trough separation of coarse and clean coal includes: separating the first and second coarse and clean coal through a heavy medium shallow trough. The above setup further separates the first and second coarse and clean coal, thus further reducing the generation of secondary coal slime caused by the high pressure of the hydrocyclone.

[0036] like Figure 1 and Figure 2 As shown, in this embodiment, the photoelectric sorting device is an X-ray photoelectric sorting machine.

[0037] like Figure 1 and Figure 2 As shown, in this embodiment, the device for cascade fluidized bed sorting is a cascade fluidized bed sorting machine.

[0038] like Figure 1 and Figure 2 As shown, the advantages of the technical solution in this embodiment are that the overall process system reduces the generation of secondary coal slime in each link, realizes the reduction of coal slime throughout the process, which is beneficial to the separation of clean coal; and the fine-grained pulverized coal is separated in advance, and different feed ranges of equipment are used for different material properties to achieve full-size gangue removal.

[0039] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0040] For purposes of the description hereinafter, spatial

[0041] In addition, it should be noted that the use of "first", "second", etc. words to qualify parts is only for the convenience of distinguishing the corresponding parts, and the above words have no special meaning unless otherwise stated, and therefore cannot be understood as limiting the scope of protection of the present application.

[0042] The above descriptions are only the preferred embodiments of the present application, and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the scope of protection of the present application.

Claims

1. A method for underground gangue discharge of friable coal, characterized in that, The method comprises: wind de-dusting of raw coal at a coal mine face to obtain lump coal and fine coal; screening of the lump coal to obtain size fraction coal; separation of the size fraction coal to obtain clean coal and gangue; raising of the clean coal to the surface and backfilling of the gangue underground; dense medium shallow-bath separation of the clean coal; the step of screening the lump coal to obtain size fraction coal comprises: screening of the lump coal by a double-layer tension screen to obtain first size fraction coal, second size fraction coal and third size fraction coal in order of decreasing particle size; the step of separating the size fraction coal to obtain clean coal and gangue comprises: separation of the first size fraction coal by photoelectric separation to obtain first clean coal and first gangue; separation of the second size fraction coal by cascade fluidization separation to obtain second clean coal and second gangue; separation of the third size fraction coal by air shaking table to obtain third clean coal and third gangue.

2. The method of claim 1, wherein, the step of raising the clean coal to the surface and backfilling the gangue underground comprises: raising of the first clean coal, the second clean coal and the third clean coal to the surface; backfilling of the first gangue, the second gangue and the third gangue underground.

3. The method of claim 1, wherein, The classification particle size of the wind de-dusting is in the range of 0.5mm to 2mm.

4. The method of claim 1, wherein, The first screening particle size of the double-layer tension screen is in the range of 40mm to 60mm, the second screening particle size of the double-layer tension screen is in the range of 5mm to 7mm, and the third screening particle size of the double-layer tension screen is less than 6mm.

5. The method of claim 2, wherein, The step of raising the first clean coal, the second clean coal and the third clean coal to the surface comprises: raising of the first clean coal and the second clean coal after being combined; separately raising the third clean coal.

6. The method of claim 1, wherein, The step of dense medium shallow-bath separation of the clean coal comprises: separation of the first clean coal and the second clean coal by the dense medium shallow-bath.

7. The method of claim 1, wherein, The photoelectric separation device is an X-ray photoelectric separator.

8. The method of claim 1, wherein, The cascade fluidization separation device is a cascade fluidization separator.

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