阅读说明：本技术 一种干法分选方法及干法分选系统 (Dry separation method and dry separation system ) 是由 王春耀 许义 朱述川 陈勇 古锋 吕建为 赵慧杰 宋瑞领 王自祥 王超 许文波 于 2021-09-10 设计创作，主要内容包括：本发明涉及煤炭分选技术领域,涉及一种干法分选方法,包括以下步骤：原煤按照第一预设粒径筛分,粒径大于第一预设粒径的送入块煤复合式分选机、块煤干法重介分选机或湿法选煤系统分选,得到一级精煤,粒径小于第一预设粒径的送入粗粒末煤振动梯级分选机分选,得到二级中间精煤；二级中间精煤按照第二预设粒径筛分,粒径大于第二预设粒径的为二级精煤,粒径小于第二预设粒径的送入细粒末煤振动梯级分选机分选,得到三级中间精煤；将三级中间精煤按照第三预设粒径筛分,粒径大于第三预设粒径的为三级精煤,粒径小于第三预设粒径的送入电选装置或磁选装置分选,得到四级精煤。本发明还提供了一种干法分选系统,应用上述的干法分选方法。(The invention relates to the technical field of coal separation, and relates to a dry separation method, which comprises the following steps: raw coal is screened according to a first preset particle size, the raw coal with the particle size larger than the first preset particle size is fed into a lump coal composite separator, a lump coal dry heavy medium separator or a wet coal separation system for separation to obtain first-grade clean coal, and the raw coal with the particle size smaller than the first preset particle size is fed into a coarse-grained and slack coal vibration step separator for separation to obtain second-grade intermediate clean coal; screening the secondary intermediate clean coal according to a second preset particle size, wherein the secondary clean coal is larger than the second preset particle size, and the fine-grained slack coal with the particle size smaller than the second preset particle size is fed into a vibrating step sorter for sorting to obtain three-level intermediate clean coal; and screening the third-stage intermediate clean coal according to a third preset particle size, wherein the third-stage clean coal is obtained when the particle size is larger than the third preset particle size, and the fourth-stage clean coal is obtained when the particle size is smaller than the third preset particle size and is sent into an electric separation device or a magnetic separation device for separation. The invention also provides a dry separation system and the dry separation method.)

1. A dry sorting method, comprising the steps of:

s01: screening raw coal according to a first preset particle size, feeding the raw coal with the particle size larger than the first preset particle size into a lump coal composite separator, a lump coal dry heavy medium separator (6) or a wet coal separation system for separation to obtain primary clean coal and primary gangue, and feeding the raw coal with the particle size smaller than the first preset particle size into a coarse-grained and fine-grained coal vibration step separator (11) for separation to obtain secondary intermediate clean coal and secondary gangue;

s02: screening the secondary intermediate clean coal according to a second preset particle size, wherein the second preset particle size is smaller than the first preset particle size, the secondary clean coal is larger than the second preset particle size, and the fine-grained slack coal with the particle size smaller than the second preset particle size is fed into a vibrating step sorter (17) for sorting to obtain tertiary intermediate clean coal and tertiary gangue;

s03: and screening the third-level intermediate clean coal according to a third preset particle size, wherein the third preset particle size is smaller than the second preset particle size, the third preset particle size is larger than the third preset particle size, the third preset particle size is the third-level clean coal, the third preset particle size is smaller than the third preset particle size, and the third preset particle size is sent into an electric separation device or a magnetic separation device for separation to obtain the fourth-level clean coal and the fourth-level gangue.

2. The dry sorting method according to claim 1, characterized in that dust particles in operation of the lump coal composite classifier or the lump coal dry heavy medium classifier (6) are collected using a dust removal unit;

and/or collecting dust particles in the operation of the coarse-grained and fine-coal vibrating and grading separator (11) by using the dust removal unit;

and/or collecting dust particles in the operation of the fine-grained pulverized coal vibrating step classifier (17) by using the dust removal unit.

3. The dry sorting method according to claim 2, characterized in that an air supply unit is used to supply air to the lump coal composite classifier or the lump coal dry dense media classifier (6);

and supplying air to the coarse-grained and fine-grained pulverized coal vibrating and grading separator (11) and the fine-grained and fine-grained pulverized coal vibrating and grading separator (17) by using the air supply unit.

4. The dry sorting method according to claim 2, wherein the dust particles collected by the dust removal unit are sent to the electric sorting device or the magnetic sorting device for sorting.

5. The dry sorting method according to claim 1, wherein in step S01, the middlings product of the coarse-grained fine coal vibratory cascade sorter (11) is re-sorted;

and/or, in step S02, the middlings product of the fine-grained slack coal vibrating step sorter (17) is reselected.

6. The dry sorting method according to claim 1, wherein the first predetermined particle size is D1, the second predetermined particle size is D2, and the third predetermined particle size is D3, and the following conditions are satisfied:

D1＝13mm；D2＝6mm；D3＝0.5mm。

7. a dry separation system, characterized in that the dry separation method according to any one of claims 1 to 6 is applied to realize the separation of the raw coal.

8. The dry sorting system of claim 7, comprising:

the primary separation unit comprises a primary vibrating screen (2), the primary separation unit also comprises a lump coal composite separator, a lump coal dry heavy medium separator (6) or a wet coal separation system, and the output end of the oversize product of the primary vibrating screen (2) is communicated with the input end of the lump coal composite separator, the lump coal dry heavy medium separator (6) or the wet coal separation system;

the secondary separation unit comprises a coarse-grained and fine-coal vibrating and grading separator (11) and a secondary vibrating screen (14), the input end of the coarse-grained and fine-coal vibrating and grading separator (11) is communicated with the output end of undersize products of the primary vibrating screen (2), and the output end of secondary middle clean coal of the coarse-grained and fine-coal vibrating and grading separator (11) is communicated with the input end of the secondary vibrating screen (14);

a third-stage sorting unit which comprises a fine particle slack coal vibrating step sorting machine (17) and a third-stage vibrating screen (21), wherein the input end of the fine particle slack coal vibrating step sorting machine (17) is communicated with the undersize product output end of the second-stage vibrating screen (14), and the third-stage intermediate clean coal output end of the fine particle slack coal vibrating step sorting machine (17) is communicated with the input end of the third-stage vibrating screen (21);

the four-stage separation unit comprises an electric separation device or a magnetic separation device, and the input end of the electric separation device or the magnetic separation device is communicated with the undersize product output end of the three-stage vibrating screen (21).

9. The dry sorting system according to claim 8, further comprising a dust removal unit, wherein the dust removal unit comprises a cyclone (24), a bag-type dust collector (26) and a collection pipeline, one end of the collection pipeline is communicated with the input end of the cyclone (24), the other end of the collection pipeline is branched and is respectively communicated with the dust discharge ports of the lump coal composite type sorting machine or the lump coal dry heavy medium sorting machine (6), the coarse-particle and fine-particle coal vibration step sorting machine (11) and the fine-particle and fine-particle coal vibration step sorting machine (17), and the top air outlet of the cyclone (24) is communicated with the input end of the bag-type dust collector (26).

10. The dry sorting system according to claim 8, wherein the primary vibrating screen (2) has a classifying size of 13mm, the secondary vibrating screen (14) has a classifying size of 6mm, and the tertiary vibrating screen (21) has a classifying size of 0.5 mm.

Technical Field

The invention relates to the technical field of coal-carbon separation, in particular to a dry separation method and a dry separation system.

Background

Coal washing is a main mode for realizing clean utilization of coal, and the current main washing modes comprise two modes: wet sorting and dry sorting.

The sorting device suitable for the slack coal with the granularity of 13mm-0 mm comprises a dense medium cyclone suitable for coarse coal with the granularity of 13mm-0.5mm, an interference bed sorting machine suitable for fine coal with the granularity of 2mm-0.5mm and the like. The wet separation method cannot treat easily-argillized coal, is high in cost and is easy to generate a large amount of slime water. The coal slime with the granularity of 0.5mm-0 is generally subjected to a froth flotation method, but the froth flotation method is high in cost and seriously depends on water resources, and the coal slime is not ideal for wet separation under the condition of water resource shortage.

In the technical field of dry separation, when the separation granularity is 13mm-0, common dry separation equipment comprises a composite separator and wind separation equipment, but the composite separator and the wind separation equipment have low separation precision, complex equipment structure and single function, and cannot realize high-precision dry separation of coal.

Therefore, a dry sorting method and a dry sorting system are needed to solve the above problems.

Disclosure of Invention

The invention aims to provide a dry method sorting method which can improve sorting precision and reduce economic cost.

In order to achieve the purpose, the invention adopts the following technical scheme:

a dry sorting method comprising the steps of:

s01: screening raw coal according to a first preset particle size, feeding the raw coal with the particle size larger than the first preset particle size into a lump coal composite separator, a lump coal dry heavy medium separator or a wet coal separation system for separation to obtain primary clean coal and primary gangue, and feeding the raw coal with the particle size smaller than the first preset particle size into a coarse-grained pulverized coal vibration step separator for separation to obtain secondary intermediate clean coal and secondary gangue;

s02: screening the secondary intermediate clean coal according to a second preset particle size, wherein the second preset particle size is smaller than the first preset particle size, the secondary clean coal is larger than the second preset particle size, and the fine-grained slack coal with the particle size smaller than the second preset particle size is fed into a vibrating step sorter for sorting to obtain three-level intermediate clean coal and three-level gangue;

s03: and screening the third-level intermediate clean coal according to a third preset particle size, wherein the third preset particle size is smaller than the second preset particle size, the third preset particle size is larger than the third preset particle size, the third preset particle size is the third-level clean coal, the third preset particle size is smaller than the third preset particle size, and the third preset particle size is sent into an electric separation device or a magnetic separation device for separation to obtain the fourth-level clean coal and the fourth-level gangue.

Optionally, collecting dust particles in the operation of the lump coal composite separator or the dry heavy medium separator by using a dust removal unit;

and/or collecting dust particles in the operation of the coarse-grained and fine-coal vibrating step separator by using the dust removal unit;

and/or collecting dust particles in the operation of the fine-grained pulverized coal vibrating step classifier by using the dust removal unit.

Optionally, supplying air to the lump coal compound separator or the lump coal dry heavy medium separator by using an air supply unit;

and supplying air to the coarse-grained and fine-grained pulverized coal vibrating and grading separator by using the air supply unit.

Optionally, the dust particles collected by the dust removal unit are sent to the electric separation device or the magnetic separation device for separation.

Optionally, in step S01, the middling product of the coarse-grained and fine-coal vibrating and grading separator is reselected;

and/or, in step S02, the middlings product of the fine-grained slack coal vibrating step classifier is reselected.

Optionally, the first preset particle size is D1, the second preset particle size is D2, and the third preset particle size is D3, and the following conditions are satisfied:

D1＝13mm；D2＝6mm；D3＝0.5mm。

another object of the present invention is to provide a dry sorting system that can improve the sorting accuracy and reduce the economic cost.

In order to achieve the purpose, the invention adopts the following technical scheme:

a dry separation system applies the dry separation method to realize the separation of the raw coal.

Optionally, the dry sorting system comprises:

the primary separation unit comprises a primary vibrating screen, the primary separation unit also comprises a lump coal composite separator, a lump coal dry heavy medium separator or a wet coal separation system, and the output end of the oversize product of the primary vibrating screen is communicated with the input end of the lump coal composite separator, the lump coal dry heavy medium separator or the wet coal separation system;

the secondary sorting unit comprises a coarse-grained and fine-coal vibrating step sorting machine and a secondary vibrating screen, the input end of the coarse-grained and fine-coal vibrating step sorting machine is communicated with the output end of a product under the primary vibrating screen, and the output end of secondary intermediate clean coal of the coarse-grained and fine-coal vibrating step sorting machine is communicated with the input end of the secondary vibrating screen;

the three-stage sorting unit comprises a fine particle slack coal vibrating step sorting machine and a three-stage vibrating screen, the input end of the fine particle slack coal vibrating step sorting machine is communicated with the output end of the undersize product of the two-stage vibrating screen, and the three-stage intermediate clean coal output end of the fine particle slack coal vibrating step sorting machine is communicated with the input end of the three-stage vibrating screen;

the four-stage separation unit comprises an electric separation device or a magnetic separation device, and the input end of the electric separation device or the magnetic separation device is communicated with the undersize product output end of the three-stage vibrating screen.

Optionally, the dry separation system further comprises a dust removal unit, the dust removal unit comprises a cyclone dust collector, a bag type dust collector and a collection pipeline, one end of the collection pipeline is communicated with the input end of the cyclone dust collector, the other end of the collection pipeline is forked and is respectively communicated with the lump coal composite separator or the dust discharge ports of the lump coal dry heavy medium separator, the coarse-particle and fine-particle coal vibration step separator, and the air outlet at the top of the cyclone dust collector is communicated with the input end of the bag type dust collector.

Optionally, the classifying particle size of the primary vibrating screen is 13mm, the classifying particle size of the secondary vibrating screen is 6mm, and the classifying particle size of the tertiary vibrating screen is 0.5 mm.

The invention has the beneficial effects that:

the invention provides a dry separation method, which can perform dry separation on low-quality raw coal by accurately and reasonably arranging tertiary screening and quartic separation and obtain the four-grade clean coal with different particle sizes meeting the precision requirement. When the dry separation method is used independently, the separation problem of the dry water-deficient area and the separation problem of the easily-slimed coal can be solved. When the dry separation method is combined with the wet separation, the separate separation of the slack coal can be realized, the separation precision of a wet separation system is improved, the separation quality is ensured, the water consumption and the coal slime quantity can be reduced, and the economic benefit is improved.

The invention also provides a dry separation system, which applies the dry separation method to realize the separation of the raw coal. When the dry separation system is used independently, the separation problem of the dry water-deficient area and the separation problem of the easily-slimed coal can be solved. When the dry separation system is combined with the wet separation equipment, the separate separation of slack coal can be realized, the separation precision of the wet separation system is improved, the separation quality is ensured, the water consumption and the coal slime amount can be reduced, and the economic benefit is improved.

Drawings

FIG. 1 is a schematic flow diagram of a dry sorting method provided by an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a dry sorting system provided in an embodiment of the present invention.

In the figure:

1. a first raw coal conveyor belt; 2. a first-stage vibrating screen; 3. a second raw coal conveyor belt; 4. a first coal surge bin; 5. a first coal feeder; 6. a lump coal dry heavy medium separator; 7. a first-stage clean coal conveying belt; 8. a first-level gangue conveying belt; 9. a second coal surge bin; 10. a second coal feeder; 11. vibrating step sorter for coarse-grained and slack coal; 12. wind bags; 13. a blower; 14. a secondary vibrating screen; 15. a third coal surge bin; 16. a third coal feeder; 17. vibrating step sorter for fine coal; 18. a secondary gangue transport belt; 19. a third-level gangue conveying belt; 20. a third-stage intermediate clean coal conveying belt; 21. a third-stage vibrating screen; 22. a fourth coal surge bin; 23. a fourth coal feeder; 24. a cyclone dust collector; 25. a first induced draft fan; 26. a bag type dust collector; 27. a second induced draft fan; 28. a dry-type electric separator; 29. a dry magnetic separator; 30. tertiary clean coal conveyer belt.

Detailed Description

The technical scheme of the invention is further explained by combining the attached drawings and the embodiment. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some but not all of the elements associated with the present invention are shown in the drawings.

In the description of the present invention, it should be noted that unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection or a removable connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The coal wet separation method has the problems of high water consumption, complex separation process, generation of a large amount of coal slime water and the like, and is not suitable for areas with shortage of water resources. The existing dry separation method has single separation function and cannot meet the complex requirement of the existing coal separation. Therefore, as shown in fig. 1, the embodiment provides a dry separation method, which can improve the separation accuracy of raw coal, realize multi-stage clean coal production, reduce economic cost, improve economic benefit, save water resources, and avoid the treatment problem of slime water.

The dry sorting method comprises the following steps:

s01: first, raw coal is screened according to a first preset particle size, optionally, a first vibrating screen is used to realize screening. And feeding the raw coal with the particle size larger than the first preset particle size into a lump coal composite separator, a lump coal dry-method heavy-medium separator 6 or a wet-method coal separation system for separation, so as to obtain primary clean coal and primary gangue. It can be known that the particle size of one-level cleaned coal is greater than first predetermined particle size, and the combined type sorter of lump coal, lump coal dry process heavy medium sorter 6 or wet process coal dressing system have considerable sorting precision when selecting the great raw coal of particle size, can think that one-level cleaned coal can reach the required precision, can export as the product. Optionally, the first preset particle size D1 is 13mm, which can effectively ensure the sorting precision of the lump coal composite type sorting machine, the lump coal dry heavy medium sorting machine 6 or the wet coal sorting system.

In order to collect dust particles formed during the operation of the lump coal composite separator or the lump coal dry method heavy medium separator 6, a dust removal unit is optionally used for collecting dust particles generated during the operation of the lump coal composite separator or the lump coal dry method heavy medium separator 6. The construction and operation of the dust removing unit will be described in detail hereinafter.

And (3) feeding the raw coal with the particle size smaller than the first preset particle size into a coarse-particle slack coal vibration step sorting machine 11 for sorting to obtain second-stage intermediate clean coal and second-stage gangue. At the moment, gangue with smaller particle size is still mixed in the secondary intermediate clean coal, so the secondary intermediate clean coal is further screened and sorted in the follow-up process.

Also in order to collect dust particles formed during use of the coarse-grained coal vibrating cascade separator 11, dust particles generated during operation of the coarse-grained coal vibrating cascade separator 11 are optionally collected using a dust removal unit. Since the lump coal composite classifier, the lump coal dry heavy medium classifier 6 and the coarse and fine coal vibration step classifier 11 all require supply of air flow, air is optionally supplied to the lump coal composite classifier or the lump coal dry heavy medium classifier 6 using an air supply unit, and likewise, air is supplied to the coarse and fine coal vibration step classifier 11 using the air supply unit.

In order to ensure the sorting accuracy of the coarse-grained and fine-coal vibrating and grading sorter 11, the middling coal product of the coarse-grained and fine-coal vibrating and grading sorter 11 is optionally re-sorted. Namely, the middling output port of the coarse-grained and fine-grained coal vibrating and grading separator 11 is communicated with the input pipeline of the coarse-grained and fine-grained coal vibrating and grading separator 11.

S02: and screening the second-stage intermediate clean coal according to a second preset particle size, optionally, screening by adopting a second vibrating screen, wherein the second preset particle size is smaller than the first preset particle size. Since the coarse-grained and fine-grained coal vibrating and grading separator 11 has separated the gangue with the larger grain size, which is smaller than the first preset grain size, from the gangue with the larger grain size, which is smaller than the first preset grain size and larger than the second preset grain size, the gangue component is considered to be less, and the separated gangue component is used as secondary clean coal. The secondary clean coal can meet the precision requirement and can be output as a product. Optionally, the second preset particle size D2 is 6mm, which can ensure that few gangue components are contained in the particles larger than the second preset particle size in the secondary intermediate cleaned coal sorted by the coarse-particle-size-coal vibrating step sorter 11, and thus the precision of the obtained secondary cleaned coal can meet the requirement.

And feeding the fine-grained slack coal with the grain size smaller than the second preset grain size into a vibrating step sorter 17 for sorting to obtain three-level intermediate clean coal and three-level gangue. At the moment, gangue with smaller grain diameter is still mixed in the three-stage intermediate clean coal, so that the three-stage intermediate clean coal is required to be further screened and sorted subsequently.

Also in order to collect dust particles formed during use of the fine particle pulverized coal vibratory step separator 17, dust particles generated during operation of the fine particle pulverized coal vibratory step separator 17 are optionally collected using a dust removal unit.

Also since the operation of the fine powder coal vibrating step classifier 17 requires the supply of the air flow, the fine powder coal vibrating step classifier 17 is optionally supplied with air using an air supply unit.

In order to ensure the sorting accuracy of the fine particle slack coal vibratory cascade sorter 17, the middling coal product of the fine particle slack coal vibratory cascade sorter 17 is optionally re-sorted. Namely, the middling coal output port of the fine-grained slack coal vibrating step sorter 17 is communicated with the input pipeline of the fine-grained slack coal vibrating step sorter 17.

S03: and screening the third-level intermediate clean coal according to a third preset particle size, optionally, screening by using a third vibrating screen, wherein the third preset particle size is smaller than the second preset particle size. Since the fine-grained slack coal vibrating step sorter 17 has sorted out the larger-grained portion of the gangue having a grain size smaller than the second predetermined grain size, it is considered that the gangue component is already small in the grains having a grain size smaller than the second predetermined grain size and larger than the third predetermined grain size, and therefore the sorted-out grains serve as the third-stage clean coal. The three-stage clean coal can meet the precision requirement and can be output as a product.

And (4) feeding the small particles with the particle size smaller than the third preset particle size into an electric separation device or a magnetic separation device for separation, thus obtaining the fourth-grade clean coal and the fourth-grade gangue. Optionally, the third preset particle size D3 is 0.5mm, which can ensure that few gangue components are contained in the particles larger than the third preset particle size in the three-stage intermediate clean coal sorted by the fine-grained slack coal vibrating step sorter 17, and thus the precision of the obtained three-stage clean coal can meet the requirement. And the small particles with the particle size smaller than the third preset particle size, namely the small particles with the particle size smaller than 0.5mm, have high sorting precision in the electric sorting device or the magnetic sorting device, so that the finally obtained four-grade clean coal can meet the precision requirement and can be output as a product.

In order to obtain an efficient collection and treatment of the dust particles generated during the sorting process, dust particles in the operation of the lump coal composite classifier or the lump coal dry heavy medium classifier 6, the coarse-particle-powder vibratory step classifier 11 and the fine-particle-powder vibratory step classifier 17 are optionally collected and treated using a dust removal unit. Optionally, the dust removing unit comprises a cyclone 24, a bag type dust remover 26 and a collecting pipeline, one end of the collecting pipeline is communicated with the input end of the cyclone 24, and the other end of the collecting pipeline is branched and is respectively communicated with the dust discharge ports of the lump coal composite type separator or the lump coal dry method heavy medium separator 6, the coarse-particle and fine-particle coal vibration step separator 11 and the fine-particle and fine-particle coal vibration step separator 17, so that dust particles enter the cyclone 24. The dust particles with slightly larger particle size have a very low dust content and a high coal dust content, and the dust particles are output from the bottom end of the cyclone dust collector 24. Optionally, in order to recover the pulverized coal therein, the output port at the bottom end of the cyclone dust collector 24 is communicated with an electric separation device or a magnetic separation device, so that the part of dust particles enters the electric separation device or the magnetic separation device to be separated to obtain the pulverized coal. The top air outlet of the cyclone dust collector 24 is communicated with the input end of the bag-type dust collector 26, that is, the dust particles with a slightly smaller particle size are output from the top end of the cyclone dust collector 24, and the dust content in the dust particles is higher, so that the dust particles enter the bag-type dust collector 26 for further dust removal. In order to recover the coal dust in the part of dust particles, the output port at the bottom end of the bag-type dust collector 26 is also communicated with the electric separation device or the magnetic separation device, so that the part of dust particles enter the electric separation device or the magnetic separation device to be separated to obtain the four-stage clean coal.

Optionally, in order to provide flow power to the airflow between the cyclone 24 and the bag house 26, a first induced draft fan 25 is provided in the conduit between the top outlet of the cyclone 24 and the inlet of the bag house 26. In order to ensure sufficient airflow power in the bag house 26, optionally, the air outlet of the bag house 26 is connected to the second induced draft fan 27.

According to the dry separation method, the tertiary screening and the quaternary separation are accurately and reasonably arranged, so that the low-quality raw coal can be subjected to dry separation, and the four-grade clean coal with different particle sizes meeting the precision requirement can be obtained. When the dry separation method is used independently, the separation problem in drought and water-deficient areas can be overcome. When the dry separation method is combined with the wet separation, the separate separation of the slack coal can be realized, the separation precision of a wet separation system is improved, the separation quality is ensured, the water consumption and the coal slime quantity can be reduced, and the economic benefit is improved.

As shown in fig. 2, the embodiment further provides a dry sorting system, which applies the dry sorting method described above, and can improve sorting accuracy and reduce economic cost.

The dry method sorting system comprises a primary sorting unit, a secondary sorting unit, a tertiary sorting unit, a quaternary sorting unit, a dedusting unit and an air supply unit.

The primary separation unit comprises a first raw coal conveying belt 1, a primary vibrating screen 2, a second raw coal conveying belt 3, a first coal buffer bin 4, a first coal feeder 5, a lump coal dry-method heavy-medium separator 6, a primary clean coal conveying belt 7 and a primary gangue conveying belt 8. Alternatively, the lump coal dry heavy medium separator 6 can be replaced by a lump coal compound separator or a wet coal separation system.

The primary vibrating screen 2 is located at the downstream of the first raw coal conveying belt 1, and raw coal enters the input end of the primary vibrating screen 2 under the conveying of the first raw coal conveying belt 1. The grading granularity of the primary vibrating screen 2 is a first preset grain diameter D1, the output end of the oversize product of the primary vibrating screen 2 is communicated with the first coal buffer bin 4, the output end of the first coal buffer bin 4 is communicated with the first coal feeder 5, and the output end of the first coal feeder 5 is communicated with the input end of the lump coal dry heavy medium separator 6. The oversize product of the primary vibrating screen 2, namely, the raw coal with the particle size larger than the first preset particle size enters a lump coal composite separator, a lump coal dry-method heavy-medium separator 6 or a wet-method coal separation system through a first coal buffer bin 4 and a first coal feeder 5 to be separated, and primary clean coal and primary gangue can be obtained. It can be known that the particle size of one-level cleaned coal is greater than first predetermined particle size, and the combined type sorter of lump coal, lump coal dry process heavy medium sorter 6 or wet process coal dressing system have considerable sorting precision when selecting the great raw coal of particle size, can think that one-level cleaned coal can reach the required precision, can export as the product. Optionally, the first preset particle size D1 is 13mm, which can effectively ensure the sorting precision of the lump coal composite type sorting machine, the lump coal dry heavy medium sorting machine 6 or the wet coal sorting system. The input end of the first-stage clean coal conveying belt 7 is communicated with the clean coal output end of the lump coal composite separator, the lump coal dry-method heavy-medium separator 6 or the wet-method coal separation system, so that the first-stage clean coal can be output conveniently. The input end of the primary gangue transport belt 8 is communicated with the gangue output end of the lump coal composite separator, the lump coal dry-method heavy-medium separator 6 or the wet-method coal separation system, so that the primary gangue can be output conveniently.

The secondary sorting unit comprises a second coal buffer bin 9, a second coal feeder 10, a coarse-grained and fine-grained coal vibrating step sorter 11, a secondary vibrating screen 14, a secondary gangue conveying belt 18 and a secondary clean coal conveying belt (not shown in the figure).

The output end of the undersize product of the first vibrating screen is communicated with the input end of a second coal buffer bin 9, the output end of the second coal buffer bin 9 is communicated with a second coal feeder 10, and the output end of the second coal feeder 10 is communicated with the input end of a coarse-grain and fine-grain coal vibrating step separator 11. Undersize products of the first vibrating screen, namely raw coal with the particle size smaller than a first preset particle size sequentially pass through a second coal buffer bin 9 and a second coal feeder 10 and enter a coarse-particle and fine-particle vibrating step sorting machine 11 for sorting, and secondary intermediate clean coal and secondary gangue are obtained. The gangue output end of the coarse-grained and slack-coal vibrating step sorter 11 is communicated with the upstream of the secondary gangue transport belt 18 so as to facilitate the output of secondary gangue. At the moment, gangue with smaller particle size is still mixed in the secondary intermediate clean coal, so the secondary intermediate clean coal is further screened and sorted in the follow-up process.

In order to ensure the sorting accuracy of the coarse-grained and fine-coal vibrating and grading sorter 11, the middling coal product of the coarse-grained and fine-coal vibrating and grading sorter 11 is optionally re-sorted. Namely, the middling output port of the coarse-grained and fine-grained coal vibrating and grading separator 11 is communicated with the input pipeline of the coarse-grained and fine-grained coal vibrating and grading separator 11.

In order to further screen the second-stage intermediate clean coal, the second-stage intermediate clean coal output end of the coarse-grain slack coal vibrating step sorting machine 11 is communicated with the input end of the second-stage vibrating screen 14, so that the second-stage intermediate clean coal can enter the second-stage vibrating screen 14 for screening. The grading granularity of the secondary vibrating screen 14 is a second preset grain diameter D2, the oversize product of the secondary vibrating screen 14 is secondary clean coal, and the oversize product output end of the secondary vibrating screen 14 is communicated with the upstream of a secondary clean coal conveying belt, so that the secondary clean coal is output conveniently. Because the coarse-grained and fine-grained coal vibrating step separator 11 has separated out the larger part of the gangue with the grain size smaller than the first preset grain size, the gangue components are few in the grains with the grain size smaller than the first preset grain size and larger than the second preset grain size, so that the screened grains are used as secondary clean coal, the accuracy can be ensured to meet the requirement, and the secondary clean coal can be output as a product. Optionally, the second preset particle size D2 is 6mm, which can ensure that few gangue components are contained in the particles larger than the second preset particle size in the secondary intermediate clean coal sorted by the coarse-particle-size-coal vibrating and grading sorter 11, and thus can ensure the accuracy of the obtained secondary clean coal.

The third-stage separation unit comprises a third coal buffer bin 15, a third coal feeder 16, a fine-grained slack coal vibrating step separator 17, a third-stage vibrating screen 21, a third-stage gangue conveying belt 19, a third-stage intermediate clean coal conveying belt 20 and a third-stage clean coal conveying belt 30.

The output end of the undersize product of the second vibrating screen is communicated with the input end of a third coal buffer bin 15, the output end of the third coal buffer bin 15 is communicated with a third coal feeder 16, and the output end of the third coal feeder 16 is communicated with the input end of a fine-particle and slack-coal vibrating step separator 17. Undersize products of the second vibrating screen, namely coal dust with the particle size smaller than a second preset particle size sequentially pass through a third coal buffer bin 15 and a third coal feeder 16 and enter a fine-particle-end coal vibrating step sorting machine 17 for sorting, and three-stage intermediate clean coal and three-stage gangue are obtained. The gangue output end of the fine-grain slack coal vibrating step sorter 17 is communicated with the upstream of the third-level gangue transport belt 19 so as to facilitate the output of the third-level gangue. At the moment, gangue with smaller grain diameter is still mixed in the three-stage intermediate clean coal, so that the three-stage intermediate clean coal is required to be further screened and sorted subsequently.

In order to ensure the sorting accuracy of the fine particle slack coal vibratory cascade sorter 17, the middling coal product of the fine particle slack coal vibratory cascade sorter 17 is optionally re-sorted. Namely, the middling coal output port of the fine-grained slack coal vibrating step sorter 17 is communicated with the input pipeline of the fine-grained slack coal vibrating step sorter 17.

In order to further screen the third-stage intermediate clean coal, the third-stage intermediate clean coal output end of the fine-particle slack coal vibrating step sorting machine 17 is communicated with the input end of the third-stage vibrating screen 21, so that the third-stage intermediate clean coal can enter the third-stage vibrating screen 21 for screening. Optionally, a third-stage intermediate clean coal conveying belt 20 is arranged between the third-stage intermediate clean coal output end of the fine-particle pulverized coal vibrating step separator 17 and the input end of the third-stage vibrating screen 21 so as to facilitate the conveying of the third-stage intermediate clean coal.

The grading granularity of the third-level vibrating screen 21 is a third preset grain diameter D3, the oversize product of the third-level vibrating screen 21 is third-level clean coal, and the oversize product output end of the third-level vibrating screen 21 is communicated with the upstream of the third-level clean coal conveying belt 30, so that the third-level clean coal is output conveniently. Since the fine-particle slack coal vibrating step separator 17 has separated the gangue with the larger particle size, which is smaller than the second preset particle size, from the gangue with the larger particle size, the gangue components are few in the particles with the particle size smaller than the second preset particle size and larger than the third preset particle size, so that the particles separated from the gangue are used as the third-level clean coal, the accuracy can be ensured to meet the requirement, and the gangue can be output as a product. Optionally, the third preset particle size D3 is 0.5mm, which can ensure that few gangue components are contained in the particles larger than the third preset particle size in the three-stage intermediate clean coal sorted by the fine-grained pulverized coal vibrating step sorter 17, and thus the accuracy of the obtained three-stage clean coal can be ensured.

The four-stage separation unit comprises a fourth coal buffer bin 22, a fourth coal feeder 23, an electric separation device or a magnetic separation device. The output end of the undersize product of the third vibrating screen is communicated with the input end of a fourth coal buffer bin 22, the output end of the fourth coal buffer bin 22 is communicated with a fourth coal feeder 23, and the output end of the fourth coal feeder 23 is communicated with the input end of the fine-particle slack coal vibrating step separator 17. Undersize products of the third vibrating screen, namely coal dust with the particle size smaller than a third preset particle size sequentially pass through a fourth coal buffer bin 22 and a fourth coal feeder 23 and enter an electric separation device or a magnetic separation device for separation, and four-grade clean coal and four-grade gangue are obtained. Alternatively, the electric separation device is a dry electric separator 28 and the magnetic separation device is a dry magnetic separator 29. The small particles with the particle size smaller than the third preset particle size, namely the small particles with the particle size smaller than 0.5mm, have high sorting precision in the electric sorting device or the magnetic sorting device, so that the finally obtained four-stage clean coal can meet the precision requirement and can be output as a product.

In order to obtain an efficient collection and treatment of the dust particles generated during the sorting process, dust particles in the operation of the lump coal composite classifier or the lump coal dry heavy medium classifier 6, the coarse-particle-powder vibratory step classifier 11 and the fine-particle-powder vibratory step classifier 17 are optionally collected and treated using a dust removal unit. Optionally, the dust removing unit includes a cyclone 24, a bag type dust collector 26 and a collecting pipeline, one end of the collecting pipeline is communicated with the input end of the cyclone 24, and the other end is branched and respectively communicated with the dust discharge ports of the lump coal composite type separator or the lump coal dry method heavy medium separator 6, the coarse-particle and fine-particle coal vibration step separator 11 and the fine-particle and fine-particle coal vibration step separator 17, so that dust particles enter the cyclone 24. The dust particles with slightly larger particle size have a very low dust content and a high coal dust content, and the dust particles are output from the bottom end of the cyclone dust collector 24. Optionally, in order to recover the pulverized coal therein, the output port at the bottom end of the cyclone dust collector 24 is communicated with an electric separation device or a magnetic separation device, so that the part of dust particles enters the electric separation device or the magnetic separation device to be separated to obtain the pulverized coal. The top air outlet of the cyclone dust collector 24 is communicated with the input end of the bag-type dust collector 26, that is, the dust particles with a slightly smaller particle size are output from the top end of the cyclone dust collector 24, and the dust content in the dust particles is higher, so that the dust particles enter the bag-type dust collector 26 for further dust removal. In order to recover the coal dust in the part of dust particles, the output port at the bottom end of the bag-type dust collector 26 is also communicated with the electric separation device or the magnetic separation device, so that the part of dust particles enter the electric separation device or the magnetic separation device to be separated to obtain the four-stage clean coal.

Optionally, in order to provide flow power to the airflow between the cyclone 24 and the bag house 26, a first induced draft fan 25 is provided in the conduit between the top outlet of the cyclone 24 and the inlet of the bag house 26. In order to ensure sufficient airflow power in the bag house 26, optionally, the air outlet of the bag house 26 is connected to the second induced draft fan 27.

Because the lump coal composite separator, the lump coal dry-method heavy-medium separator 6, the coarse-particle and fine-particle coal vibrating step separator 11 and 17 need air supply during operation, optionally, the dry separation system further comprises an air supply unit. The air supply unit comprises an air bag 12 and an air blower 13, the output end of the air blower 13 is communicated with the air bag 12, the air bag 12 is communicated with an air supply pipeline, one end of the air supply pipeline is divided into a plurality of branches, and the branches are respectively communicated with the lump coal composite separator or the lump coal dry method heavy medium separator 6, the coarse-particle and fine-particle coal vibration step separator 11 and the fine-particle and fine-particle coal vibration step separator 17 so as to realize air supply.

It can be known that this dry separation system can carry out the dry separation to low-grade raw coal to obtain the different particle size's of level four clean coal that accords with the precision requirement through carrying out accurate reasonable arrangement with cubic screening and quartic sorting. Namely, first-grade clean coal with the grain diameter larger than 13mm, second-grade clean coal with the grain diameter within the range of 6mm-13mm, third-grade clean coal with the grain diameter within the range of 0.5mm-6mm and fourth-grade clean coal with the grain diameter smaller than 0.5 mm. The dry separation system can realize high-precision separation of low-quality raw coal, can ensure separation quality, can reduce water consumption and coal slime, and improves economic benefit.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.