Dense medium separation coal slime upgrading process

Abstract

The invention discloses a dense medium separation coal slime upgrading process, which comprises the following steps of: pumping coal slime into a coal slime grading cyclone by using a water pump, and obtaining underflow and overflow flow under the feeding pressure of 110Kpa-150Kpa; the particle size of the underflow is 0.15-1 mm, the underflow enters a coarse slime barrel, and the coarse slime barrel adjusts the concentration of the slime in the barrel to 30-33%; the coal slime with the concentration of 30%-33% is pumped into a spiral sorting machine, and concentrate and tailings are obtained; the concentrate automatically flows into a dewatering and deliming system; tailings are pumped into a separation grading system; and a fine particle outlet of the overflow, dehydration and deliming system and a fine particle outlet of the separation and classification system are connected with the concentration system. The concentration of underflow of the coal slime grading cyclone is adjusted through the coarse coal slime barrel, so that the concentration of coal slime entering the spiral sorting machine is kept at 30-33%, the sorting efficiency of the spiral sorting machine is improved, meanwhile, the ash content of concentrate and tailings of the spiral sorting machine is reduced, and the quality of coal slime products is improved.

Description

Technical Field

[0001] The invention relates to the technical field of coal slime separation, and in particular to a heavy medium separation coal slime quality improvement process. Background Art

[0002] Heavy medium coal preparation is a physical coal preparation technology. It uses a liquid with a density between clean coal and gangue as a medium for sorting. Its principle is to use the sinking and floating principle. Clean coal with a density lower than that of the medium floats, while gangue or medium coal with a density higher than that of the medium sinks. Then they are collected and classified into different products. In the preparation stage of heavy medium coal preparation, in order to ensure the accuracy of heavy medium sorting, wet screening is used to remove fine particles before heavy medium washing of raw coal. During the wet screening process, the fine particles are mixed with water to produce coal slime water and heavy medium separation. The coal slime water produced in the dehydration and demediation stages of the selected various products is usually classified by a hydraulic concentration and classification cyclone, and the coarse and fine coal slime is recovered by a spiral separator, and then dehydrated by a linear high-frequency screen and a centrifuge to obtain the coarse and fine coal slime product; due to the change in the particle size composition of the raw coal, the bottom flow concentration of the hydraulic concentration and classification cyclone is large, and the separation accuracy of the spiral separator is reduced, resulting in the coarse and fine coal slime carrying ash, the ash content of the heavy medium separation coal slime product is high, and the product quality is unstable. Therefore, it is necessary to design a separation process that improves the coal slime separation accuracy and reduces the product ash content. Summary of the invention

[0003] The object of the present invention is to overcome the deficiencies in the above-mentioned prior art and provide a heavy medium separation coal slime quality improvement process, in which the concentration of the bottom flow of the coal slime grading cyclone is adjusted by a coarse coal slime bucket, so that the coal slime concentration entering the spiral separator is maintained at 30-33%, thereby improving the separation efficiency of the spiral separator, reducing the ash content of the spiral separator concentrate and the spiral separator tailings, and improving the quality of the coal slime product.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a heavy medium separation coal slime quality improvement process, comprising the following steps: step S1: pumping the heavy medium separation coal slime water into the coal slime classification cyclone for concentration and classification according to the particle size of 0.15mm, the feed pressure of the coal slime classification cyclone is 110Kpa~150Kpa, and the coal slime classification cyclone bottom flow and the coal slime classification cyclone overflow are obtained; step S2: the coal slime particle size of the coal slime classification cyclone bottom flow is 0.15-1mm, and the coal slime with a particle size of 0.15-1mm enters the coarse coal slime barrel, and the coarse coal slime barrel adjusts the coal slime concentration in the barrel to 30-33% concentration; step S3: The coal slime with a concentration of 30-33% described in step S2 is pumped into a spiral separator for sorting to obtain a spiral separator concentrate and a spiral separator tailings; Step S4: The spiral separator concentrate described in step S3 flows by gravity into a dehydration and deashing system, and the coarse particle outlet of the dehydration and deashing system is connected to a clean coal bucket; Step S5: The spiral separator tailings described in step S3 are pumped into a separation and grading system, and the coarse particle outlet of the separation and grading system is connected to a gangue bucket; Step S6: The overflow of the coal slime grading cyclone described in step S1, the fine particle outlet of the dehydration and deashing system in step S4, and the fine particle outlet of the separation and grading system in step S5 are all connected to a concentration system.

[0005] Preferably, the coarse coal slime barrel includes a barrel body, a concentration meter, a water supply valve and a controller, the concentration meter is installed on the barrel body at a height of 1 / 3 from the ground, the water supply valve is installed on the top of the barrel body, the controller is installed on the outer wall of the barrel body, the controller is connected to the concentration meter and the water supply valve, and the controller adjusts the opening of the water supply valve based on the coal slime concentration transmitted by the concentration meter.

[0006] Preferably, the coarse coal slime barrel also includes a motor and an agitator, the output shaft of the motor is connected to the agitator, the motor is installed on the top of the barrel body, the agitator extends along the height direction of the barrel body to the bottom of the barrel body, and the motor drives the agitator to stir the coal slime in the barrel body.

[0007] Preferably, two coarse coal slime barrels are arranged in parallel.

[0008] Preferably, the dehydration and deashing system comprises the following steps: step S401: the concentrate of the spiral separator flows into the laminated screen by gravity to obtain the material on the laminated screen and the coal slime under the laminated screen; step S402: the material on the laminated screen in step S401 is sent to a coarse coal slime centrifuge for dehydration to obtain a coarse clean coal slime product, and the coarse clean coal slime product is sent to a clean coal barrel; step S403: the coal slime under the laminated screen in step S401 is sent to a concentration system through the fine particle outlet of the laminated screen for solid-liquid separation.

[0009] Preferably, the separation and grading system comprises the following steps: step S501: feeding the spiral separator tailings into a gangue cyclone to obtain a gangue cyclone overflow and a gangue cyclone underflow; step S502: feeding the gangue cyclone underflow described in step S501 into a high-frequency screen for screening to obtain high-frequency screen overscreen material and high-frequency screen underscreen coal slime; step S503: feeding the high-frequency screen overscreen material described in step S502 into a gangue bucket; step S504: feeding the gangue cyclone overflow described in step S501 and the high-frequency screen underscreen coal slime described in step S502 into a concentration system for solid-liquid separation.

[0010] Preferably, the concentration system comprises the following steps: Step S601: sending the input coal slime into a coal slime concentration tank for solid-liquid separation to obtain medium coal slime; Step S602: sending the medium coal slime in step S601 into an ultra-high pressure filter press for filtration and dehydration to obtain a medium coal slime product which is sent into a medium coal barrel.

[0011] Preferably, the sieve gap of the high-frequency sieve is 0.35 mm.

[0012] Preferably, the water supply valve is an electric water supply valve with an inner diameter of 150 mm.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1. The present invention adjusts the concentration of the underflow of the coal slime classification cyclone through the coarse coal slime bucket, so that the coal slime concentration entering the spiral separator is maintained at 30-33%, thereby improving the separation efficiency of the spiral separator, reducing the ash content of the spiral separator concentrate and the spiral separator tailings, and improving the quality of the coal slime product.

[0015] 2. The coarse coal slime barrel of the present invention is provided with a concentration meter on the side wall and a water supply valve on the top. The concentration meter continuously monitors the concentration of the coal slime in the coarse coal slime barrel and sends the concentration data to the controller. The controller adjusts the opening of the water supply valve according to the received concentration data, thereby improving the stability of the coal slime concentration in the coarse coal slime barrel.

[0016] 3. The coarse coal slime barrel of the present invention is provided with an agitator, which is driven by a motor to rotate, thereby preventing the coal slime in the coarse coal slime barrel from settling, making the coal slime in the coarse coal slime barrel evenly distributed, and improving the uniformity of the coal slime concentration in the coarse coal slime barrel.

[0017] The present invention is further described in detail below through the accompanying drawings and examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present invention;

[0019] Figure 2 It is a structural schematic diagram of the coal slime bucket of the present invention.

[0020] Description of reference numerals:

[0021] 1—barrel body; 2—concentration meter; 3—water supply valve;

[0022] 4—controller; 5—motor; 6—agitator. DETAILED DESCRIPTION

[0023] like Figure 1 As shown, the present invention discloses a heavy medium separation coal slime quality improvement process.

[0024] Example 1

[0025] The heavy medium separation coal slime upgrading process includes the following steps:

[0026] Step S1: Pump the heavy medium separation coal slime water into the coal slime classification cyclone for concentration and classification according to the particle size of 0.15 mm. The feed pressure of the coal slime classification cyclone is 110Kpa-150Kpa to obtain the coal slime classification cyclone bottom flow and the coal slime classification cyclone overflow;

[0027] The particle size of the overflow of the coal slime grading cyclone is less than 0.15mm, the particle size of the bottom flow of the coal slime grading cyclone is 0.15-1mm, the diameter of the coal slime grading cyclone is 350mm, and the feed pump for pumping heavy medium separation coal slime water uses a variable frequency pump to facilitate the adjustment of the feed pressure of the coal slime grading cyclone.

[0028] Step S2: The particle size of the coal slime in the bottom flow of the coal slime classification cyclone is 0.15-1 mm, and the coal slime with a particle size of 0.15-1 mm enters the coarse coal slime barrel, and the coarse coal slime barrel adjusts the coal slime concentration in the barrel to 30-33%;

[0029] like Figure 2 As shown, the coarse coal slime barrel includes a barrel body 1, a concentration meter 2, a water supply valve 3 and a controller 4. The concentration meter 2 is installed on the barrel body 1 at a height of 1 / 3 from the ground, the water supply valve 3 is installed on the top of the barrel body 1, and the controller 4 is installed on the outer wall of the barrel body 1. The controller 4 is connected to the concentration meter 2 and the water supply valve 3. The controller 4 adjusts the opening of the water supply valve 3 based on the coal slime concentration transmitted by the concentration meter 2.

[0030] The bottom flow of the coal slime grading cyclone is sent into the barrel body 1 through a pipeline. The concentration meter 2 on the side wall of the barrel body 1 continuously detects the concentration of the coal slime in the barrel body 1 and transmits the concentration value to the controller 4. If the concentration meter 2 detects that the coal slime in the barrel body 1 is greater than 33%, the controller 4 controls the opening of the water supply valve 3 after receiving the concentration data, and the water supply valve 3 supplies water to the barrel body 1. The concentration meter 2 continuously detects the coal slime concentration in the barrel body 1. When the concentration meter 2 detects that the coal slime concentration in the barrel body 1 is lower than 33%, the controller 4 controls the water supply valve 3 to close, and the water supply valve 3 stops supplying water to the barrel body 1. The coal slime concentration in the barrel body 1 is maintained at 30%-33% through the concentration meter 2 to avoid pipeline blockage caused by excessive bottom flow concentration of the coal slime grading cyclone. At the same time, maintaining the coal slime concentration at 30%-33% can improve the sorting efficiency of the spiral separator and reduce the amount of ash in the concentrate and tailings separated by the spiral separator.

[0031] like Figure 2 As shown, the coarse coal slime barrel also includes a motor 5 and an agitator 6. The output shaft of the motor 5 is connected to the agitator 6. The motor 5 is installed on the top of the barrel body 1. The agitator 6 extends along the height direction of the barrel body 1 to the bottom of the barrel body 1. The motor 5 drives the agitator 6 to stir the coal slime in the barrel body 1.

[0032] After the bottom flow of the coal slime classification cyclone enters the barrel body 1, the coal slime is unevenly distributed. The coal slime in the barrel body 1 is continuously stirred by the agitator 6 to keep the coal slime concentration in the barrel body 1 uniform, thereby improving the sorting efficiency of the spiral separator.

[0033] Step S3: pumping the coal slime with a concentration of 30-33% in step S2 into a spiral separator for separation to obtain spiral separator concentrate and spiral separator tailings;

[0034] The 30-33% concentration of coal slime in the coarse coal slime barrel is pumped into the spiral classifier through a frequency conversion pump and rotates along the spiral groove. During the movement, light and heavy particles are affected by gravity, centrifugal force, friction and water flow pressure in the spiral groove. Materials with different particle sizes and densities have different movement trajectories in the spiral groove, and high-density coal slime and low-density coal slime are separated. At the bottom of the spiral classifier, high-density coal slime and low-density coal slime are collected by different chutes, respectively, to obtain spiral classifier tailings and spiral classifier concentrate, and the coal slime concentration is controlled at 30-33% to avoid excessive coal slime concentration causing material accumulation in the spiral classifier feed distribution box, blockage of the feed pipe or uneven feeding of the spiral classifier, affecting the coal slime sorting effect.

[0035] Step S4: the concentrate of the spiral separator in step S3 flows into the dehydration and deashing system by gravity, and the coarse particle outlet of the dehydration and deashing system is connected to the clean coal bucket;

[0036] The dehydration and deashing system includes the following steps:

[0037] Step S401: The concentrate of the spiral separator flows into the laminated screen by gravity, and the laminated screen overscreen and the laminated screen underscreen coal slime are obtained;

[0038] The particle size of the coal slime on the laminated sieve is greater than 0.074 mm, and the particle size of the coal slime under the laminated sieve is less than 0.074 mm.

[0039] Step S402: sending the material on the laminated screen in step S401 to a coarse coal slime centrifuge for dehydration to obtain a coarse clean coal slime product, and sending the coarse clean coal slime product to a clean coal barrel;

[0040] After the coarse coal slime centrifuge dehydrates the material on the laminated screen, the material on the laminated screen is sent to the clean coal barrel.

[0041] Step S403: The coal slime screened off by the laminated screen in step S401 is sent to a concentration system through the fine particle outlet of the laminated screen for solid-liquid separation.

[0042] The coal slime under the laminated screen is sent along the pipeline to the coal slime thickening tank for solid-liquid separation. The coal slime thickening tank sends the dehydrated coal slime under the laminated screen to the ultra-high pressure filter press for filtration and dehydration to obtain the medium coal product, which is then sent to the medium coal barrel.

[0043] Step S5: The tailings from the spiral separator in step S3 are pumped into a separation and grading system, and the coarse particle outlet of the separation and grading system is connected to a gangue barrel.

[0044] The separation grading system includes the following steps:

[0045] Step S501: sending the spiral separator tailings into the gangue cyclone to obtain the gangue cyclone overflow and the gangue cyclone underflow;

[0046] Step S502: sending the underflow of the gangue cyclone in step S501 to a high-frequency screen for screening to obtain the high-frequency screen oversize and the high-frequency screen undersize coal slime;

[0047] The screen gap of the high-frequency screen is 0.35mm. The particle size of the coal slime on the high-frequency screen is 0.35-1mm, and the particle size of the coal slime under the high-frequency screen is less than 0.35mm.

[0048] Step S503: sending the material screened by the high-frequency screen in step S502 into the gangue bucket;

[0049] Step S504: sending the overflow of the gangue cyclone in step S501 and the coal slime under the high-frequency screen in step S502 to a concentration system for solid-liquid separation.

[0050] The coal slime and gangue cyclone overflow under the high-frequency screen enter the coal slime concentration tank for solid-liquid separation. The separated coal slime is sent to the ultra-high pressure filter press for filtration and dehydration, and the medium coal product is sent to the medium coal barrel.

[0051] Step S6: The overflow of the coal slime classification cyclone in step S1, the fine particle outlet of the dehydration and deashing system in step S4, and the fine particle outlet of the separation and classification system in step S5 are all connected to the concentration system.

[0052] Step S601: sending the input coal slime into the coal slime concentration tank for solid-liquid separation to obtain medium coal slime;

[0053] The input coal slime includes coal slime classification cyclone overflow, coal slime under the laminated screen, gangue cyclone overflow and coal slime under the high-frequency screen.

[0054] Step S602: The medium coal slime in step S601 is sent to an ultra-high pressure filter press for filtration and dehydration, and the obtained medium coal slime product is sent to a medium coal barrel.

[0055] Two coarse coal slime barrels are arranged in parallel.

[0056] A slime bucket serves as an emergency backup bucket.

[0057] The water supply valve 3 is an electric water supply valve with an inner diameter of 150 mm.

[0058] Example 1 was used to process the 1st to 10th batches of raw coal. The washed raw coal was numbered 1-10 in sequence according to the batch number. The feed concentration of the spiral separator, the ash content of the spiral separator concentrate and the spiral separator tailings, and the ash content of the clean coal slime product after centrifuge dehydration were detected and recorded. The test results are shown in Table 1.

[0059] Comparative Example 1

[0060] The difference between Comparative Example 1 and Example 1 is that the underflow of the coal slime classification cyclone flows into the spiral separator by gravity, and the concentration of the coal slime entering the spiral separator is not adjusted.

[0061] Comparative Example 1 was used to process the 1st to 10th batches of mine raw coal. The raw coal to be washed was numbered 1-10 in sequence according to the serial number of its batch. The feed concentration of the spiral separator, the ash content of the spiral separator concentrate and the spiral separator tailings, and the ash content of the clean coal slime product after centrifuge dehydration were tested and recorded. The test results are shown in Table 1.

[0062] Table 1 shows the test results of the raw coal batches 1 to 10 processed by Example 1 and Comparative Example 1 respectively.

[0063] Table 1

[0064]

[0065] As can be seen from Table 1, the ash content of the spiral separator concentrate treated in Example 1 is lower than that of the same batch of spiral separator concentrate obtained in Comparative Example 1, indicating that the technical solution provided by the present application can reduce the ash content of the spiral separator concentrate by adjusting the feed concentration of the spiral separator, and the ash content of the coarse and clean coal slime product obtained in Example 1 is lower than that of the same batch of coarse and clean coal slime product obtained in Comparative Example 1, indicating that the technical solution provided by the present application can reduce the ash content of the clean coal slime product; It can be calculated from the data in Table 1 that the 1st to 1st batch of the ... For the 0th batch of raw coal, the average feed concentration of the spiral separator was 31%, the average ash content of the spiral separator concentrate was 13.32%, and the average ash content of the coarse coal slime product was 11.39%. For the 1st to 10th batches of raw coal treated using Comparative Example 1, the average feed concentration of the spiral separator was 39%, the average ash content of the spiral separator concentrate was 16.39%, and the average ash content of the coarse coal slime product was 16.07%, indicating that the technical solution provided in the present application can improve the sorting effect of the spiral separator and ensure the precise separation of coarse coal slime and high-ash coal slime.

[0066] It can be seen from Table 1 that the deviation between the ash content of the spiral separator concentrate and the ash content of the coarse coal slime product treated in Example 1 is greater than the deviation between the ash content of the spiral separator concentrate and the coarse coal slime product in Comparative Example 1, indicating that the technical solution provided in the present application can improve the concentrate deashing effect of the spiral separator by adjusting the feed concentration of the spiral separator; it can be seen from the data calculation in Table 1 that the 1st to 10th batches of raw coal treated in Example 1 have an average deviation of 1.93% in the ash content of the spiral separator concentrate and the coarse coal slime product ash content, and the 1st to 10th batches of raw coal treated in Comparative Example 1 have an average deviation of 0.32% in the ash content of the spiral separator concentrate and the coarse coal slime product ash content, indicating that the technical solution provided in the present application can increase the concentrate deashing amount of the spiral separator and improve the quality of the coarse coal slime product.

[0067] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A heavy medium separation coal slime upgrading process, characterized in that: The following steps are involved: Step S1: Pump the heavy medium separation coal slime water into the coal slime classification cyclone for concentration and classification according to the particle size of 0.15 mm, the feed pressure of the coal slime classification cyclone is 110Kpa-150Kpa, and obtain the coal slime classification cyclone bottom flow and coal slime classification cyclone overflow; Step S2: The particle size of the coal slime in the bottom flow of the coal slime classification cyclone is 0.15-1 mm, and the coal slime with a particle size of 0.15-1 mm enters the coarse coal slime barrel, and the coarse coal slime barrel adjusts the coal slime concentration in the barrel to 30-33%; Step S3: pumping the coal slime with a concentration of 30-33% in step S2 into a spiral separator for separation to obtain spiral separator concentrate and spiral separator tailings; Step S4: the concentrate of the spiral separator in step S3 flows into the dehydration and deashing system by gravity, and the coarse particle outlet of the dehydration and deashing system is connected to the clean coal bucket; Step S5: the tailings of the spiral separator in step S3 are pumped into a separation and classification system, and the coarse particle outlet of the separation and classification system is connected to a gangue barrel; Step S6: The overflow of the coal slime classification cyclone in step S1, the fine particle outlet of the dehydration and deashing system in step S4, and the fine particle outlet of the separation and classification system in step S5 are all connected to the concentration system.

2. A heavy medium separation coal slime upgrading process according to claim 1, characterized in that: The coarse coal slime barrel comprises a barrel body (1), a concentration meter (2), a water supply valve (3) and a controller (4); the concentration meter (2) is installed at a height of 1 / 3 of the barrel body (1) from the ground; the water supply valve (3) is installed at the top of the barrel body (1); the controller (4) is installed on the outer side wall of the barrel body (1); the controller (4) is connected to the concentration meter (2) and the water supply valve (3); and the controller (4) adjusts the opening of the water supply valve (3) based on the coal slime concentration transmitted by the concentration meter (2).

3. A heavy medium separation coal slime upgrading process according to claim 2, characterized in that: The coarse coal slime barrel further comprises a motor (5) and a stirrer (6); the output shaft of the motor (5) is connected to the stirrer (6); the motor (5) is mounted on the top of the barrel body (1); the stirrer (6) extends along the height direction of the barrel body (1) to the bottom of the barrel body (1); the motor (5) drives the stirrer (6) to stir the coal slime in the barrel body (1).

4. A heavy medium separation coal slime upgrading process according to claim 1, characterized in that: Two coarse coal slime barrels are arranged in parallel.

5. A heavy medium separation coal slime upgrading process according to claim 1, characterized in that: The dehydration and deashing system comprises the following steps: Step S401: The concentrate of the spiral separator flows into the laminated screen by gravity to obtain the laminated screen overscreen and the laminated screen underscreen coal slime; Step S402: sending the material on the laminated screen in step S401 into a coarse coal slime centrifuge for dehydration to obtain a coarse clean coal slime product, and sending the coarse clean coal slime product into a clean coal barrel; Step S403: The coal slime under the laminated screen in step S401 is sent to a concentration system through the fine particle outlet of the laminated screen for solid-liquid separation.

6. A heavy medium separation coal slime upgrading process according to claim 1, characterized in that: The separation and classification system comprises the following steps: Step S501: sending the spiral separator tailings into a gangue cyclone to obtain a gangue cyclone overflow and a gangue cyclone underflow; Step S502: sending the underflow of the gangue cyclone in step S501 to a high-frequency screen for screening to obtain the high-frequency screen oversize and the high-frequency screen undersize coal slime; Step S503: sending the material on the high-frequency screen in step S502 into a waste rock bucket; Step S504: sending the overflow of the gangue cyclone in step S501 and the coal slime under the high-frequency screen in step S502 to a concentration system for solid-liquid separation.

7. A heavy medium separation coal slime upgrading process according to claim 1, characterized in that: The concentration system comprises the following steps: Step S601: sending the input coal slime into the coal slime concentration tank for solid-liquid separation to obtain medium coal slime; Step S602: The medium coal slime described in step S601 is sent to an ultra-high pressure filter press for filtration and dehydration, and the obtained medium coal slime product is sent to a medium coal barrel.

8. A heavy medium separation coal slime upgrading process according to claim 6, characterized in that: The sieve gap of the high-frequency sieve is 0.35 mm.

9. A heavy medium separation coal slime upgrading process according to claim 2, characterized in that: The water supply valve (3) is an electric water supply valve with an inner diameter of 150 mm.

Images