A coarse coal slime segmented desliming and dehydration process

Abstract

The present invention discloses a process for staged desliming and dehydration of coarse coal slime, comprising the following steps: the coal slime enters an interference bed separator, which performs TBS overflow on the coarse coal slime to obtain a first coal slime with a particle size of 0.15 mm to 1 mm; the first coal slime enters a desliming screen feed bucket, water is added to the desliming screen feed bucket to stir the first coal slime in the desliming screen feed bucket, and the first coal slime in the desliming screen feed bucket is mixed with water. The first coal slime is then pumped into a grading and concentrating cyclone group by a feed pump on the desliming screen feed bucket; the grading and concentrating cyclone group grades the first coal slime mixed in water; the first coal slime in the underflow of the grading and concentrating cyclone group enters a screening machine for two-stage screening and desliming, and a second coal slime is obtained through first-stage screening and desliming. Compared with the prior art, the staged desliming and dehydration process of coarse coal slime of the present invention can improve the dehydration efficiency of coarse and fine coal slime, obtain a coarse and fine coal slime product with qualified ash content, and can also protect the filter cloth in the pressure filter, reducing equipment maintenance costs.

Description

Technical Field

[0001] The invention belongs to the technical field of coarse coal slime processes, and in particular relates to a coarse coal slime segmented desliming and dehydration process. Background Art

[0002] With the continuous advancement of coal preparation technology, the "three-stage" coal preparation method of gravity separation, separation, and flotation has become the mainstream process in coal preparation plants. Coarse coal slime separation primarily targets materials with diameters between 1 and 0.25 mm, and the most commonly used equipment is an interference bed separator. However, the coarse and clean coal slime product obtained after separation using an interference bed separator often contains a significant amount of high-ash fines with diameters less than 0.25 mm, resulting in excessive ash content in the coarse and clean coal slime.

[0003] At the same time, the fine particle size of the sorted coarse clean coal leads to long dehydration times and high product moisture. Existing technology addresses this issue by mixing the desludged coarse clean coal. However, the large particle size of the added material during mixing causes significant wear on the filter cloth, increasing equipment maintenance costs.

[0004] Therefore, in order to solve the above technical problems, it is necessary to provide a coarse coal slime segmented desliming and dehydration process.

[0005] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0006] The object of the present invention is to provide a staged desliming and dehydration process for coarse coal slime, which can improve the dehydration efficiency of coarse and fine coal slime, obtain a coarse and fine coal slime product with qualified ash content, and at the same time protect the filter cloth in the pressure filter, thereby reducing equipment maintenance costs.

[0007] To achieve the above-mentioned object, a specific embodiment of the present invention provides a coarse coal slime staged desliming and dehydration process, comprising the following steps:

[0008] S1. Preprocessing:

[0009] S1.1. The coarse coal slime enters the interference bed separator, which performs TBS overflow on the coarse coal slime to obtain the first coal slime with a diameter of 0.15 mm to 1 mm;

[0010] S1.2. The first coal slime enters the desliming screen feed barrel. Water is added to the desliming screen feed barrel and stirred to mix the first coal slime in the desliming screen feed barrel with the water. The first coal slime is then pumped into the graded thickening cyclone group by the feed pump on the desliming screen feed barrel.

[0011] S1.3, the classification and concentration cyclone group classifies the first coal slime mixed in water;

[0012] S2, Desliming: The first coal slime in the bottom flow of the graded concentrating cyclone group enters the screening machine for two-stage screening and desliming. The second coal slime is obtained through the first stage screening and desliming. The third coal slime is obtained through the second stage screening and desliming. The undersize water after the second stage screening and desliming enters the flotation machine for flotation to obtain the fourth coal slime.

[0013] S3, dehydration: The second coal slime enters the coarse and clean coal slime centrifuge for dehydration, and the third coal slime enters the pressure filter and is mixed with the fourth coal slime to obtain the fifth coal slime, which is then dehydrated by the pressure filter;

[0014] S4. Finished product: The dehydrated second coal slime and the fifth coal slime are mixed to obtain a comprehensive clean coal product.

[0015] In one or more embodiments of the present invention, the screening machine is equipped with a first-stage desludging screen, the screen gap of the first-stage desludging screen is 0.4-0.5 mm, the screening machine is equipped with a second-stage desludging screen, the second-stage desludging screen is below the first-stage desludging screen, the screen gap of the second-stage desludging screen is 0.2-0.3 mm, and a conveyor belt is installed below the second-stage desludging screen.

[0016] In one or more embodiments of the present invention, a centrifugal bucket is provided in the pressure filter, and the sieve gap of the centrifugal bucket is 0.38-0.42 mm.

[0017] In one or more embodiments of the present invention, a first through slot is provided on the secondary desludging screen, and a grinding plate is slidably connected in the first through slot.

[0018] In one or more embodiments of the present invention, a support cylinder is fixedly connected to the lower panel of the secondary desludging screen, a bracket is slidably connected to the support cylinder, and one end of the bracket away from the support cylinder is fixedly connected to the lower panel of the grinding plate.

[0019] In one or more embodiments of the present invention, a sliding block is slidably connected in the support tube, one end of the bracket is fixedly connected to the sliding block, a second through slot is formed on the support tube, and the bracket passes through the second through slot.

[0020] In one or more embodiments of the present invention, a spring is fixedly connected to the upper plate of the sliding block, and one end of the spring away from the sliding block is fixedly connected to the lower plate of the secondary desludging screen.

[0021] In one or more embodiments of the present invention, a pair of side panels are fixedly connected to the side walls of the grinding plate, and the first through groove is provided with a grinding groove matching the side panels.

[0022] In one or more embodiments of the present invention, the upper end surfaces of the grinding plate and the side plates are frosted surfaces.

[0023] In one or more embodiments of the present invention, the maximum distance between the upper end surface of the grinding plate and the lower end surface of the first through groove is 0.3 mm.

[0024] Compared with the existing technology, the coarse coal slime segmented desliming and dehydration process of the present invention can improve the dehydration efficiency of the coarse and fine coal slime, obtain a coarse and fine coal slime product with qualified ash content, and at the same time protect the filter cloth in the pressure filter, thereby reducing equipment maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments described in the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0026] Figure 1 This is a process flow chart of a coarse coal slime staged desliming and dehydration process according to one embodiment of the present invention;

[0027] Figure 2 This is a schematic structural diagram of equipment used in a coarse coal slime staged desliming and dehydration process according to one embodiment of the present invention;

[0028] Figure 3 A schematic structural diagram of a screening machine for a coarse coal slime staged desliming and dehydration process according to an embodiment of the present invention;

[0029] Figure 4 A cross-sectional view of a screening machine for a coarse coal slime staged desliming and dehydration process according to an embodiment of the present invention;

[0030] Figure 5 A cross-sectional view of a secondary desludging screen for a coarse coal slime segmented desludging and dehydration process according to one embodiment of the present invention. Figure 1 ;

[0031] Figure 6 A cross-sectional view of a secondary desludging screen for a coarse coal slime segmented desludging and dehydration process according to one embodiment of the present invention. Figure 2 ;

[0032] Figure 7 A cross-sectional view of a support cylinder for a coarse coal slime staged desliming and dehydration process according to an embodiment of the present invention;

[0033] Description of main reference numerals:

[0034] 1. Interference bed separator; 2. Desliming screen feed barrel; 3. Grading and concentrating cyclone group; 4. Screening machine; 41. First-stage desliming screen; 42. Second-stage desliming screen; 421. First through-trough; 4211. Grinding trough; 422. Grinding plate; 4221. Side plate; 423. Support cylinder; 4231. Second through-trough; 4232. Sliding block; 4233. Bracket; 4234. Spring; 43. Conveyor belt; 44. Feeder; 5. Coarse and clean coal slime centrifuge; 6. Pressure filter; 7. Flotation machine. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0036] like Figure 1 and Figure 2 As shown, a coarse coal slime staged desliming and dehydration process in one embodiment of the present invention includes the following steps:

[0037] S1. Preprocessing:

[0038] S1.1. The coarse coal slime enters the interference bed separator 1, which performs TBS overflow on the coarse coal slime to obtain a first coal slime with a diameter of 0.15 mm to 1 mm;

[0039] S1.2. The first coal slime enters the desliming screen feed barrel 2. Water is added to the desliming screen feed barrel 2 and stirred to mix the first coal slime in the desliming screen feed barrel with the water. The first coal slime is then pumped into the graded thickening cyclone group 3 by the feed pump on the desliming screen feed barrel.

[0040] S1.3, the classification and concentration cyclone group 3 classifies the first coal slime mixed in water;

[0041] S2, Desliming: The first coal slime in the underflow of the graded concentrating cyclone group 3 enters the screening machine 4 for two-stage screening and desliming. The first stage of screening and desliming produces the second coal slime, and the second stage of screening and desliming produces the third coal slime. The underflow after the second stage of screening and desliming enters the flotation machine 7 for flotation to produce the fourth coal slime.

[0042] S3, dehydration: The second coal slime enters the coarse and clean coal slime centrifuge 5 for dehydration, and the third coal slime enters the pressure filter 6 and is mixed with the fourth coal slime to obtain the fifth coal slime, which is dehydrated by the pressure filter 6;

[0043] S4. Finished product: The dehydrated second coal slime and the fifth coal slime are mixed to obtain a comprehensive clean coal product.

[0044] Figure 1 In the table, “+” represents the material on the sieve and “-” represents the material under the sieve.

[0045] Research has found that the lower limit of coarse coal slime particle size is 0.25mm. Coarse coal slimes with particle sizes below 0.25mm contain a large amount of high-ash materials. These high-ash materials cannot be completely removed in the subsequent dehydration and desludging process and ultimately appear in the coarse clean coal product. Because the ash content of the part below 0.25mm is high, while the ash content of the part above 0.25mm is often qualified, in order to ensure that the ash content of the coarse clean coal slime product meets the standard, it is often necessary to artificially reduce the ash content of the part above 0.25mm, which is the "back-ash" phenomenon. As a result, some low-ash clean coal above 0.25mm is lost in the underflow.

[0046] In order to solve the above problems, Figures 2 to 7 As shown, the screening machine 4 is equipped with a first-stage desludging screen 41, the screen gap of the first-stage desludging screen 41 is 0.4-0.5 mm, and the screening machine 4 is equipped with a second-stage desludging screen 42, which is located below the first-stage desludging screen 41 and has a screen gap of 0.2-0.3 mm. A conveyor belt 43 is installed below the second-stage desludging screen 42. Preferably, the screen gap of the first-stage desludging screen 41 is 0.43 mm, and the screen gap of the second-stage desludging screen 42 is 0.23 mm.

[0047] Specifically, the first coal slime in the bottom flow of the graded concentrating cyclone group 3 enters the screening machine 4 for two-stage screening and desliming. The first coal slime first falls on the first-stage desliming screen 41. The first-stage desliming screen 41 first screens and deslimes the first coal slime to obtain the oversize material on the first-stage desliming screen 41. This oversize material is the second coal slime with a particle size greater than 0.43 mm and a qualified ash content.

[0048] The resulting second coal sludge is then fed into a pressurized filter 6 equipped with a centrifuge bucket for dehydrating the second coal sludge. Specifically, the centrifuge bucket has a 0.4 mm sieve gap, which allows for rapid centrifugation of water from the second coal sludge. The centrifuge liquid separated by the pressurized filter 6 enters the fine magnetic tail bucket.

[0049] After desliming and screening by the primary desliming screen 41, the undersize water of the primary desliming screen 41 naturally falls on the secondary desliming screen 42. The particle size of these materials is less than 0.43 mm. After desliming and screening by the secondary desliming screen 42, the oversize material of the secondary desliming screen 42 is obtained. The particle size of this oversize material is between 0.23-0.43 mm, and it is the third coal slime with qualified ash content. The third coal slime is then transported to the pressure filter 6 for dehydration.

[0050] The undersize material of the secondary desliming screen 42 naturally falls onto the conveyor belt 43 and is transported to the flotation machine 7 for flotation to obtain the fourth coal slime with qualified ash content. The fourth coal slime is then also transported to the pressure filter 6 for dehydration.

[0051] It is worth noting that the fourth coal slime obtained after flotation by the flotation machine 7 is too fine in particle size and needs to be dehydrated using a filter cloth. At the same time, because the fourth coal slime is too fine in particle size, it leads to the problem of long dehydration time and high product moisture. In order to solve this problem, Figures 2 to 4 As shown, the flotation cell 7 and the pressure filter 6 are connected. The third coal slime on the secondary desliming screen 42 and the fourth coal slime floated by the flotation cell 7 are mixed in the pressure filter 6 to produce a fifth coal slime with uniform particle size. Since the particle size limit of the fifth coal slime is 0.43 mm, this coal slime with a particle size less than 0.43 mm not only reduces dehydration time but also minimizes damage to the filter cloth in the pressure filter 6.

[0052] Finally, the dehydrated second coal slime and the fifth coal slime are mixed to obtain a comprehensive clean coal product.

[0053] In order to further improve the dehydration effect and protect the filter cloth in the pressure filter 6, Figures 5 to 7 As shown, the feeder 44 is provided with a first through slot 421, into which a grinding plate 422 is slidably connected. A support cylinder 423 is welded to the lower panel of the secondary desludging screen 42, to which a bracket 4233 is slidably connected. The end of the bracket 4233, which is away from the support cylinder 423, is welded to the lower panel of the grinding plate 422.

[0054] Specifically, a sliding block 4232 is slidably connected within the support cylinder 423. One end of the bracket 4233 is integrally formed on the sliding block 4232. A second through slot 4231 is defined in the support cylinder 423, and the bracket 4233 extends through the second through slot 4231. A spring 4234 is welded to the upper panel of the sliding block 4232. The end of the spring 4234 away from the sliding block 4232 is welded to the lower panel of the secondary desludging screen 42.

[0055] Specifically, bracket 4233 supports the grinding plate 422 within the first through-slot 421. The supporting force of bracket 4233 is provided by the elastic tension of spring 4234. When the screening machine 4 is in operation, it drives the secondary desludging screen 42 to vibrate at a high frequency. Spring 4234 continuously expands and contracts as it vibrates, further increasing the vibration frequency of the grinding plate 422. The third coal slime on the secondary desludging screen 42 jumps from the right end of the secondary desludging screen 42 to the left end of the secondary desludging screen 42. During this process, the third coal slime falls from the first through-slot 421 onto the violently vibrating grinding plate 422. After more violent vibration, the edges of the third coal slime on the grinding plate 422 are smoothed, preventing the third coal slime from damaging the filter cloth on the pressure filter 6.

[0056] Furthermore, the upper end surfaces of the grinding plate 422 and side plate 4221 are frosted. Specifically, as the third coal slurry bounces on the grinding plate 422, the frosted surface further polishes the third coal slurry, making its outer surface smoother. This also removes high-ash materials adhering to the third coal slurry, lowering its ash content. This removed high-ash material becomes the undersize of the secondary desludging screen 42 and is sent to the flotation machine 7 for flotation.

[0057] Furthermore, a pair of side panels 4221 are integrally formed on the sidewalls of the polishing plate 422. The first through-slot 421 is provided with a polishing groove 4211 that matches the side panels 4221. When vibrating within the first through-slot 421, the polishing plate 422 can slide out of the first through-slot 421, and the maximum distance between the upper end surface of the polishing plate 422 and the lower end surface of the first through-slot 421 after sliding out is 0.3 mm.

[0058] Specifically, third coal slime with a particle size smaller than 0.3 mm, which bounces on grinding plate 422, will fall through the gap between first slot 421 and grinding plate 422 onto the upper surface of side plate 4221. As grinding plate 422 continuously slides within first slot 421, the upper surface of side plate 4221 constantly slaps against the walls of grinding slot 4211, further polishing the third coal slime on side plate 4221 and making it smoother. Finally, the third coal slime on side plate 4221 falls onto conveyor belt 43. This better protects the filter cloth on pressure filter 6 during subsequent dehydration.

[0059] Specifically, as the conveyor belt 43 continuously rotates to transport the undersize material from the secondary desliming screen 42, the third coal slime that falls from the side plate 4221 evenly falls onto the continuously rotating conveyor belt 43. This third coal slime, along with the undersize material from the secondary desliming screen 42, enters the flotation machine 7 for flotation to produce the fifth coal slime. This not only accelerates the dehydration of the fifth coal slime during subsequent dehydration, but also makes the particle size of the fifth coal slime more uniform, providing better protection for the filter cloth on the pressure filter 6.

[0060] Furthermore, the third coal slime on the secondary desliming screen 42 can be dehydrated independently without waiting for the fourth coal slime to be floated by the flotation machine 7 , thereby accelerating the dehydration speed and improving the use efficiency of the pressure filter 6 .

[0061] During operation, the coarse coal slime enters the interference bed separator 1 and, after overflowing the TBS, produces the first coal slime. This first coal slime is then directed into the desliming screen feed bucket 2. After water is added to the desliming screen feed bucket 2, the desliming screen feed pump pumps the first coal slime into the graded concentrating cyclone group 3. The underflow from the graded concentrating cyclone group 3 enters the primary desliming screen 41 for screening and desliming to produce the second coal slime. The second coal slime then enters the coarse and clean coal slime centrifuge 5 for dehydration.

[0062] The water under the first-stage desliming screen 41 enters the second-stage desliming screen 42 for secondary desliming to obtain the third coal slime. The water under the second-stage desliming screen 42 enters the flotation machine 7 for flotation to obtain the fourth coal slime. The third coal slime and the fourth coal slime enter the pressure filter 6 together for dehydration to obtain the fifth coal slime. The dehydrated second coal slime and the fifth coal slime are mixed to obtain a comprehensive clean coal product.

[0063] This process rationally sets the screen size for the two-stage desliming and classification of coarse coal slime. The increased screen size of the first-stage desliming screen ensures the effective removal of high-ash materials smaller than 0.23mm from the coarse clean coal, avoiding the phenomenon of high-ash materials smaller than 0.25mm causing the coarse clean coal product to carry over ash with qualified materials larger than 0.23mm, thereby improving the coarse clean coal product recovery rate. The material on the second-stage desliming screen serves as the mixed material for flotation clean coal dehydration, effectively preventing wear of the filter cloth in the pressure filter 6 and reducing the maintenance cost of the pressure filter 6.

[0064] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0065] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A coarse coal slime staged desliming and dehydration process, characterized in that: The steps include: S1. Preprocessing: S1.

1. The coarse coal slime enters the interference bed separator, which performs TBS overflow on the coarse coal slime to obtain the first coal slime with a diameter of 0.15 mm to 1 mm; S1.

2. The first coal slime enters the desliming screen feed barrel. Water is added to the desliming screen feed barrel and stirred to mix the first coal slime in the desliming screen feed barrel with the water. The first coal slime is then pumped into the graded thickening cyclone group by the feed pump on the desliming screen feed barrel. S1.3, the classification and concentration cyclone group classifies the first coal slime mixed in water; S2, Desliming: The first coal slime in the bottom flow of the graded concentrating cyclone group enters the screening machine for two-stage screening and desliming. The second coal slime is obtained through the first stage screening and desliming. The third coal slime is obtained through the second stage screening and desliming. The undersize water after the second stage screening and desliming enters the flotation machine for flotation to obtain the fourth coal slime. S3, dehydration: The second coal slime enters the coarse and clean coal slime centrifuge for dehydration, and the third coal slime enters the pressure filter and is mixed with the fourth coal slime to obtain the fifth coal slime, which is then dehydrated by the pressure filter; S4, finished product: the dehydrated second coal slime and the fifth coal slime are mixed to obtain a comprehensive clean coal product; The screening machine is equipped with a first-stage desludging screen, and a second-stage desludging screen is installed on the screening machine. The second-stage desludging screen is below the first-stage desludging screen, and a first through slot is provided on the second-stage desludging screen. When the screening machine is working, the second-stage desludging screen is driven to vibrate at a high frequency. A grinding plate is slidably connected in the first through slot, and the maximum distance between the upper end surface of the grinding plate and the lower end surface of the first through slot is 0.3 mm. The grinding plate can slide out of the first through slot when vibrating in the first through slot.

2. A coarse coal slime staged desliming and dehydration process according to claim 1, characterized in that: The screen gap of the first-stage desludging screen is 0.4-0.5 mm, the screen gap of the second-stage desludging screen is 0.2-0.3 mm, and a conveyor belt is installed below the second-stage desludging screen.

3. The process for staged desliming and dehydration of coarse coal slime according to claim 1, characterized in that: A centrifugal bucket is provided in the pressure filter, and the sieve gap of the centrifugal bucket is 0.38-0.42 mm.

4. The process for staged desliming and dehydration of coarse coal slime according to claim 1, characterized in that: A support cylinder is fixedly connected to the lower panel of the secondary desludging screen, a bracket is slidably connected to the support cylinder, and one end of the bracket away from the support cylinder is fixedly connected to the lower panel of the grinding plate.

5. A coarse coal slime staged desliming and dehydration process according to claim 4, characterized in that: A sliding block is slidably connected in the support tube, one end of the bracket is fixedly connected to the sliding block, a second through slot is opened on the support tube, and the bracket passes through the second through slot.

6. A coarse coal slime staged desliming and dehydration process according to claim 5, characterized in that: A spring is fixedly connected to the upper plate of the sliding block, and one end of the spring away from the sliding block is fixedly connected to the lower plate of the secondary desludging screen.

7. The process for staged desliming and dehydration of coarse coal slime according to claim 5, characterized in that: A pair of side plates are fixedly connected to the side walls of the grinding plate, and a grinding groove matching the side plates is formed on the first through groove.

8. The process for staged desliming and dehydration of coarse coal slime according to claim 3, characterized in that: The upper end surfaces of the grinding plate and the side plates are frosted surfaces.

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