A lignite treatment method based on pre-slaking and desludging

Abstract

The application discloses a lignite treatment method based on pre-slurry and deslurry, and belongs to the technical field of lignite washing and processing, and aims at at least one problem of poor selectivity, poor floatability, serious fine slurry pollution, large reagent consumption and high flotation cost in the prior art. The method comprises the following steps: mixing lignite raw materials with water, performing slurry dispersion treatment on the coal-water mixture, realizing pre-slurry treatment of the lignite, and obtaining slurry lignite; performing deslurry treatment on the slurry lignite, obtaining fine coal slurry and coarse coal; performing flotation on the coarse coal, obtaining flotation clean coal and flotation tailings, and completing the treatment of the lignite. The application can be used for lignite flotation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of lignite washing and processing, and particularly relates to a lignite processing method based on pre-mudification and desliming. BACKGROUND

[0002] Lignite has the characteristics of high water, high ash and low calorific value, and flotation is an effective means for treatment.

[0003] However, due to the low metamorphic degree of lignite, the surface contains a large amount of oxygen-containing functional groups such as carboxyl and hydroxyl groups, the hydrophobicity is poor, and the porosity is developed, which causes poor conventional flotation separation effect, large reagent consumption, mudification of clay mineral components in lignite to form high-ash fine mud, and serious fine mud covering and entrainment behavior in the flotation process, which reduces the flotation selectivity and pollutes the clean coal, and the fine mud covering and entrainment behavior is an important reason for low recovery of lignite combustible.

[0004] In addition, the use of surface modification, ultrasonic cleaning and other means can appropriately enhance the hydrophobicity of the lignite surface, remove the high-ash fine mud, and strengthen the flotation effect, but the effect is poor and the energy consumption is large. SUMMARY

[0005] In view of the above analysis, the present application aims to provide a lignite processing method based on pre-mudification and desliming to solve at least one of the problems of poor selectivity, poor floatability, serious fine mud pollution, large reagent consumption and high flotation cost in the prior art.

[0006] The purpose of the present application is mainly realized through the following technical scheme.

[0007] The present application provides a lignite processing method based on pre-mudification and desliming, comprising the following steps:

[0008] Step 1: mixing lignite raw material with water, and performing mudification and dispersion treatment on the coal-water mixture to realize pre-mudification treatment of the lignite, and obtain mudified lignite;

[0009] Step 2: desliming treatment of the mudified lignite to obtain fine coal slime and coarse coal;

[0010] Step 3: flotation of the coarse coal to obtain flotation clean coal and flotation tailings, and complete the treatment of the lignite.

[0011] Further, the mass ratio of the lignite raw material to water is 1:4-6.

[0012] Further, the step 1 further comprises the following steps before the step 1:

[0013] The mined lignite is naturally dried and then crushed to obtain lignite raw material.

[0014] Further, the step 1 and the step 2 further comprise the following steps:

[0015] The particle size analysis is carried out on the argillized lignite to obtain the particle size level composition of the argillized lignite.

[0016] Further, the step 3 comprises the following steps:

[0017] Step 31: the coarse coal and water are added into the flotation tank to mix and wet, and a flotation slurry is obtained;

[0018] Step 32: the collector is added into the flotation slurry to fully stir;

[0019] Step 33: the frother is added into the flotation slurry containing the collector to fully stir;

[0020] Step 34: the flotation gas is introduced into the flotation tank, and after aeration, froth is scraped to obtain the flotation clean coal and the flotation tailings.

[0021] Further, in the step 31, the concentration of the flotation slurry is 60-100 g / L.

[0022] Further, in the step 32, the amount of the collector corresponding to each ton of the coarse coal is 1.0-2.0 kg.

[0023] Further, in the step 33, the amount of the frother corresponding to each ton of the coarse coal is 0.2-0.6 kg.

[0024] Further, in the step 32, the collector comprises a sodium oleate solution and a metal salt solution, and the molar ratio of the oleate ion to the metal ion is 2:1-1:2.

[0025] Further, the heavy metal ion in the metal salt solution is a divalent metal ion or a trivalent metal ion.

[0026] Compared with the prior art, the present application can at least achieve one of the following beneficial effects.

[0027] The lignite treatment method based on pre-argillization desliming provided by the present application does not involve a complex process, has small investment, high separation efficiency and obvious economic benefits. On the one hand, the argillization of the lignite raw material is fully considered according to the difference in argillization properties of the useful components and the gangue minerals, the high-ash fine slurry is hydrated into fine coal slurry, and the separation of the fine coal slurry from the coarse coal is carried out, the gangue components are further removed through subsequent flotation, the covering and entrainment behaviors of the high-ash fine slurry in the flotation process are effectively reduced, the clean coal pollution and the fine particles in the underflow are avoided, and thus the flotation selectivity is greatly increased, the clean coal quality is improved, and the separation cost is saved. On the other hand, the argillization mainly occurs on the surface of the lignite raw material particles, the surface of the lignite raw material particles tends to be smooth, the hydrophilic sites and the number of pores are reduced, the hydrophobicity of the surface of the lignite raw material particles is improved, the collector molecules are spread on the surface of the coal, and thus the consumption of the flotation reagents is reduced.

[0028] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained through the embodiments described and the accompanying drawings, which are particularly pointed out. Attached Figure Description

[0029] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0030] Figure 1 A flowchart of the lignite treatment method based on pre-sliming and desliming provided by the present invention;

[0031] Figure 2 This is a schematic diagram of the integrated mud-desliming and desliming equipment in the lignite treatment method based on pre-mud-desliming and desliming provided by the present invention.

[0032] Figure 3 This is a top view of the first screen plate in the lignite treatment method based on pre-sliming and desliming provided by the present invention.

[0033] Figure 4 This is a schematic diagram of the coal-water feed pipe in the lignite treatment method based on pre-sliming and desliming provided by the present invention.

[0034] Figure label:

[0035] 1-Cylinder; 2-Chutter; 3-First screen plate; 31-Flow stabilizer; 32-Through hole; 33-Flow slowing plate; 4-Second screen plate; 5-Agitator wheel; 51-Wheel plate; 52-Reinforcing hole; 6-Buffer zone; 7-Mudification zone; 8-Desliming zone; 9-Coarse coal discharge port; 10-Flushing water port; 11-Drive motor; 12-Drive shaft; 13-Coal-water feed pipe; 131-First pipe; 132-Second pipe; 133-Convex ring; 14-Coal-water feed port; 15-First brush; 16-Second brush; 17-Rack; 18-Gear; 19-L-shaped mounting rod; 20-Fine coal slime discharge port. Detailed Implementation

[0036] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0037] This invention provides a method for treating lignite based on pre-sliming and desliming, see [link to relevant documentation]. Figure 1 This includes the following steps:

[0038] Step 1: After mixing lignite raw material with water, the coal-water mixture is subjected to mud dispersion treatment to realize pre-mud treatment of lignite, and mud lignite is obtained.

[0039] Step 2: The mud lignite is subjected to desliming treatment to obtain fine coal slime and coarse coal.

[0040] Step 3: The coarse coal is subjected to flotation to obtain flotation clean coal and flotation tailings (including gangue, etc.), and the treatment of lignite is completed.

[0041] Compared with the prior art, the lignite treatment method based on pre-mud desliming provided by the present application does not involve a complex process, has small investment, high separation efficiency, and obvious economic benefits. On the one hand, the pre-mud of lignite raw material is fully considered in view of the difference in mud properties of useful components and gangue minerals in the lignite raw material, the high-ash fine mud (for example, clay minerals) is hydrated into fine coal slime, which is separated from coarse coal, and the gangue components are further removed through subsequent flotation, which can effectively reduce the covering and entrainment behavior of high-ash fine mud in the flotation process, avoid clean coal pollution and bottom flow entrainment, thereby greatly increasing the flotation selectivity, improving the clean coal quality, and saving the separation cost. On the other hand, the mud phenomenon mainly occurs on the surface of the lignite raw material particles, which makes the surface of the lignite raw material particles smooth, reduces the number of hydrophilic sites and pores, and thus improves the hydrophobicity of the surface of the lignite raw material particles, promotes the spreading of the collector molecules on the coal surface, and thus reduces the consumption of flotation reagents.

[0042] In order to be able to fully mud the lignite raw material, the mass ratio of lignite raw material to water is 1:4-6 (for example, 1:5) by way of example.

[0043] In order to further improve the flotation effect, the above step 1 further includes the following step before step 1:

[0044] The lignite mined from the coalfield is naturally dried to remove external moisture and then subjected to crushing treatment to obtain lignite raw material with a particle size of <0.5 mm.

[0045] In actual application, the particle size level composition of the mud lignite will directly affect the selection of various process parameters in the subsequent desliming process, and therefore, the above step 1 and step 2 further include the following step:

[0046] The particle size of the mud lignite is analyzed to obtain the particle size level composition of the mud lignite.

[0047] Exemplarily, the particle size grades of the sludgy lignite are generally divided into five particle size grades of 0.5-0.25 mm, 0.25-0.125 mm, 0.125-0.074 mm, 0.074-0.045 mm and -0.045 mm, and meanwhile, the particle size analysis also needs to analyze the specific components in each particle size grade, for example, the specific mass percentage of fine coal slime, coarse coal and tail coal and the like.

[0048] In order to enable effective flotation of the coarse coal, the above step 3 comprises the following steps:

[0049] Step 31: the coarse coal and water are mixed and wetted in the flotation tank to obtain a flotation slurry, and the concentration of the flotation slurry is 60-100 g / L;

[0050] Step 32: the collector is added to the flotation slurry and fully stirred, and the dosage of the collector corresponding to each ton of coarse coal is 1.0-2.0 kg;

[0051] Step 33: the frother is added to the flotation slurry containing the collector and fully stirred, and the dosage of the frother corresponding to each ton of coarse coal is 0.2-0.6 kg;

[0052] Step 34: the flotation gas (for example, air) is introduced into the flotation tank, and after aeration, the froth is scraped to obtain the flotation clean coal and the flotation tailings.

[0053] It should be noted that the present application adopts a specific composition of the collector which is matched with the sludgy lignite, and specifically, the collector comprises a sodium oleate (polar collector) solution and a metal salt solution, the heavy metal ion in the metal salt solution is divalent or trivalent, and the molar ratio of the oleate ion to the metal ion is 2:1-1:2. In this way, the polar collector sodium oleate and the metal salt solution are used in cooperation, the metal ion is bonded with the oxygen element in the surface of the sludgy lignite, the adsorption of the sodium oleate is promoted, the metal ion and the sodium oleate first form an oleic acid complex spontaneously, and then are adsorbed to the coal surface, which can significantly change the chemical properties of the lignite surface and improve the surface hydrophobicity; in addition, the sodium oleate and the metal salt solution are common chemical products, which are low in price and easy to obtain, the reagent dosage is small during flotation, and the reagent cost is saved.

[0054] Exemplarily, in the above step 1, the sludging and dispersing treatment can adopt a turnover sludging device, a forced stirring device, a self-milling device or a semi-self-milling device, and specifically, the sludging time of the turnover sludging device is 30-60 min, the sludging time of the forced stirring device is 15-20 min, the stirring speed is 1500-2000 rpm, and the milling time of the self-milling device or the semi-self-milling device is 3-10 min.

[0055] Alternatively, in the above lignite treatment method, the sludging and desliming can adopt a sludging and desliming integrated device, and specifically, see Figure 2, including coal water feeding pipe 13, desliming barrel, first screen plate 3, second screen plate 4 and stirring wheel 5 arranged in the desliming barrel, the first screen plate 3 and the second screen plate 4 divide the space in the desliming barrel into buffer zone 6, desliming zone 7 and desliming zone 8 from top to bottom, the buffer zone 6 corresponds to the fine coal slime discharge port 20 and the coal water feeding port 14 opened on the desliming barrel, the coal water feeding pipe 13 is connected with the coal water feeding port 14, the stirring wheel 5 is arranged in the desliming zone 7, and the desliming zone 8 corresponds to the coarse coal discharge port 9 and the washing water port 10 opened on the desliming barrel.

[0056] In the implementation, the coal water mixture is slowly supplied into the buffer zone 6 from the coal water feeding port 14 through the coal water feeding pipe 13, and the flow rate of the coal slurry is further reduced under the action of the first screen plate 3; the coal slurry in the buffer zone 6 is slowly supplied into the desliming zone 7 through the gap of the first screen plate 3, the stirring wheel 5 rotates to stir the coal slurry, and the mechanical shearing force is used to realize the full desliming of the coal slurry; the deslimed coal slurry is slowly supplied into the desliming zone 8 through the gap of the second screen plate 4, the washing water is supplied into the desliming zone 7 through the washing water port 10, the deslimed coal slurry is washed, and the fine coal slime and the coarse coal are separated, under the driving of the washing water, the fine coal slime with small mass is taken to the fine coal slime discharge port 20 located at the top end of the desliming barrel and discharged from the fine coal slime discharge port 20, and the coarse coal with large mass is discharged from the coarse coal discharge port 9 located at the bottom end of the desliming barrel.

[0057] The desliming and desliming integrated equipment with the above structure integrates the desliming and desliming treatment of the coal slime in the inner cavity of the same desliming barrel, uses the first screen plate 3 and the second screen plate 4 as the flow stabilizer, can control the flow rate of the coal slurry, reduce the mutual influence of the buffer zone 6, the desliming zone 7 and the desliming zone 8, realize the independent and efficient operation of each region, and thus ensure the separation efficiency of the fine coal slime and the coarse coal; since the flow direction of the coal slurry is opposite to the flow direction of the washing water, the upward washing water can wash the gap of the first screen plate 3 and the second screen plate 4 and the residues in the desliming barrel, avoid the blockage of the gap of the first screen plate 3, the gap of the second screen plate 4 and the desliming barrel by the fine coal slime, realize the self-cleaning of the desliming and desliming integrated equipment, and ensure the cleaning efficiency and the long-term stable operation of the desliming and desliming integrated equipment.

[0058] For the structure of the first screen plate 3 and the second screen plate 4, see Figure 3The mounting ring and the flow stabilizing sheet arranged in the ring inner area, the flow stabilizing sheet is in the shape of a grid, some of the grids are provided with flow stabilizing nets 31, and the remaining grids are through holes 32, wherein the through holes 32 can ensure that the washing water flows smoothly and quickly upwards to wash the coal slurry in the desliming area 8, the slurrification area 7 and the buffer area 6, ensuring the desliming efficiency and effect, and the flow stabilizing nets 31 can appropriately isolate the desliming area 8, the slurrification area 7 and the buffer area 6, reduce the liquid level fluctuation of the buffer area 6 and the desliming area 8, thereby reducing the influence of the disturbance generated by the rotation of the stirring wheel 5 on the buffer area 6 and the desliming area 8.

[0059] Exemplarily, referring to Figure 3 , the shapes of the through holes 32 and the flow stabilizing nets 31 are both rectangular, and a plurality of through holes 32 and a plurality of flow stabilizing nets 31 are arranged alternately, that is, the flow stabilizing nets 31 are arranged in every other grid hole.

[0060] In order to further reduce the influence of the rotation of the stirring wheel 5 on the buffer area 6 and the desliming area 8, the above-mentioned first net plate 3 and the second net plate 4 further comprise a flow slowing plate 33, which is arranged on the side of the flow stabilizing sheet facing the slurrification area 7. From the perspective of smooth flow of the flow stabilizing and washing water, the flow slowing plate 33 is fixedly connected with the side edge of the flow stabilizing net 31, because the fluctuation generated by the rotation of the stirring wheel 5 is mainly along the radial direction of the slurrification and desliming cylinder. By arranging the flow slowing plate 33, the fluctuation in the slurrification area 7 can be pre-stabilized, further reducing the influence of the rotation of the stirring wheel 5 on the buffer area 6 and the desliming area 8, ensuring uniform distribution of the coal slurry during flow, and avoiding too fast or uneven flow speed to reduce the treatment efficiency and effect.

[0061] It can be understood that in order to realize the installation and rotation of the stirring wheel 5, the above-mentioned slurrification and desliming integrated device further comprises a driving motor 11 and a driving shaft 12, the stirring wheel 5 is sleeved on the driving shaft 12, one end of the driving shaft 12 is fixedly connected with the output shaft of the driving motor 11, and the driving motor 11 drives the driving shaft 12 and the stirring wheel 5 to rotate synchronously, thereby agitating and slurrifying the coal slurry in the slurrification area 7.

[0062] In order to improve the high shear forced slurrification effect, the structure of the stirring wheel 5, specifically, comprises a wheel plate 51 and a reinforcing hole 52 arranged on the wheel plate 51, and by arranging the reinforcing hole 52, bubbles can be generated during the agitation of the coal slurry, thereby improving the high shear forced slurrification effect.

[0063] In order to further improve the effect of high shear forced mudification, the number of reinforcing holes 52 is multiple, and the multiple reinforcing holes 52 are arranged along the vertical direction of the wheel plate 51. From top to bottom, the width of the wheel plate 51 and the area of the reinforcing hole 52 gradually increase. In this way, during the rotation of the driving shaft 12, the shear force on the coal slurry is gradually increased through the gradually increasing wheel plate 51, the mixing and homogenization degree of the coal slurry is improved, and the coal slurry is ensured to be subjected to sufficient strong shear mudification during the treatment process, thereby achieving a more efficient mudification effect.

[0064] It can be understood that, in order to facilitate the desliming and discharge of coarse coal, the above-mentioned mudification and desliming cylinder includes a cylinder body 1 and a chute 2, the bottom of the cylinder body 1 is open, the chute 2 is buckled at the bottom opening of the cylinder body 1, the flushing water port 10 is arranged on the side wall of the chute 2, and the coarse coal discharge port 9 is arranged at the bottom end of the chute 2.

[0065] Considering that the coal water inlet will inevitably deposit too much coal slime after long-term feeding, causing blockage, in the prior art, the pipeline needs to be disassembled for blockage, but this method needs to pause the coal slime mudification and desliming process, which is complex. In the embodiment, the coal water feeding pipe 13 is a telescopic branch, as shown in Figure 4 , which includes a first pipe 131 and a second pipe 132 connected in sequence, the first pipe is located outside the mudification and desliming cylinder, the second pipe 132 is located inside the mudification and desliming cylinder, the second pipe 132 is sleeved on the outer wall of the first pipe 131 and is in slidable sealing connection with the first pipe 131, the first pipe 131 is located outside the mudification and desliming cylinder, the second pipe 132 is provided with a convex ring 133 at one end close to the first pipe 131, the second pipe 132 is located inside the mudification and desliming cylinder, and the convex ring 133 is located outside the mudification and desliming cylinder.

[0066] The above-mentioned mudification and desliming integrated equipment further includes a feeding pipe cleaning member, the feeding pipe cleaning member includes a first brush 15, the brush rod end of the first brush 15 is fixedly connected with the first pipe 131, the brush end of the first brush 15 protrudes into the second pipe 132, the bristles of the first brush 15 are in contact with the inner wall of the second pipe 132, as shown in Figure 4 , in this way, the operator can move the second pipe 132 relative to the first pipe 131 by pulling the convex ring 133 back and forth, and the first brush 15 can brush and wash the inner wall of the second pipe 132.

[0067] In order to be able to brush the discharge end of the second pipe 132, the above-mentioned feeding pipe cleaning member further comprises a second brush 16, a rack 17, a gear 18 and an L-shaped mounting rod 19, one end of the rack 17 is fixedly connected with the inner wall of the de-slurrying cylinder, the other end is suspended, the gear 18 is rotatably connected with the outer wall of the second pipe 132 through a gear shaft, the gear 18 is perpendicularly engaged with the rack 17, one end of the L-shaped mounting rod 19 is fixedly connected with the gear 18, the other end of the L-shaped mounting rod 19 is fixedly connected with the brush rod end of the second brush 16, the bristles of the second brush 16 are in contact with the discharge end of the second pipe 132. In this way, when the second pipe 132 reciprocates up and down, the gear 18 will reciprocate on the rack 17, thereby driving the gear 18 to rotate and the L-shaped mounting rod 19 to oscillate, so that the bristles reciprocally oscillate relative to the discharge end of the second pipe 132, and the discharge end of the second pipe 132 is brushed.

[0068] Example 1

[0069] The lignite treatment method of the present embodiment comprises the following steps:

[0070] Step a: The lignite sample is naturally air-dried to remove external moisture, and then crushed to below 0.5 mm by a crusher to improve the degree of dissociation of useful components and gangue minerals. In order to avoid excessive crushing, the screen undersize is collected in a sample bag after each crushing is completed, and the oversize is returned to the crusher for re-crushing.

[0071] Step b: The lignite raw material obtained in step a is mixed with water and subjected to de-slurrying and dispersion treatment to obtain de-slurried lignite, the stirring speed is 1500 rpm, and the de-slurrying process lasts for 10 min.

[0072] Step c: The de-slurried sample is subjected to screen separation treatment, and the particle size composition of the lignite raw material and the de-slurried lignite is compared. The proportion of the -0.045 mm particle size fraction increases from 29.56% to 36.89%, and the ash content increases by 1.29%.

[0073] Step d: The de-slurried lignite is de-slurried to obtain fine coal slime and coarse coal;

[0074] Step e: The coarse coal is subjected to flotation, the pulp concentration is controlled at 80 g / L, the impeller speed is 1800 r / min, the scraper speed is 42 r / min, and the air charge is adjusted to 0.1 m 3 / (m 2(×min). Sodium oleate solution and CaCl2 solution were used as collectors. The amount of sodium oleate was fixed at 1.025 kg / t, and the molar ratio of calcium ions to sodium oleate was 2:1 to 1:2. Secondary octanol was used as the frother at a dosage of 0.25 g / t. After the coal-water mixture was slurried for 2 minutes, the collector was added, and stirring continued for another 2 minutes before adding the frother and stirring for 0.5 minutes. After aerating for 10 seconds, foam scraping was started to collect the clean coal for 3 minutes.

[0075] The particle size distribution before and after mudification in Example 1 is shown in Table 1, and the flotation index of clean coal before and after mudification and desliming in Example 1 is shown in Table 2.

[0076] Table 1. Particle size distribution before and after mudification in Example 1

[0077]

[0078]

[0079] Table 2. Flotation parameters of clean coal before and after mudification and desliming in Example 1.

[0080]

[0081] Example 2

[0082] The difference between the lignite treatment method in this embodiment and that in Embodiment 1 is that the metal salt solution used in step e, flotation, is FeCl3 solution.

[0083] The flotation parameters of clean coal before and after mudification and desliming in Example 2 are shown in Table 3.

[0084] Table 3. Flotation parameters of clean coal before and after mudification and desliming in Example 2.

[0085]

[0086] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A lignite treatment method based on pre-slaking and desliming, characterized by, The method comprises the following steps: Step 1: mixing lignite raw material with water, and performing mudification and dispersion treatment on the coal-water mixture to realize pre-mudification treatment of the lignite, and obtaining mudified lignite; Step 2: performing desliming treatment on the mudified lignite to obtain fine coal slime and coarse coal; Step 3: performing flotation on the coarse coal to obtain flotation clean coal and flotation tailings, and completing the treatment of the lignite; The mudification and desliming are performed by using a mudification and desliming integrated device, the mudification and desliming integrated device comprises a coal-water feeding pipe, a mudification and desliming cylinder, and a first mesh plate, a second mesh plate and a stirring wheel arranged in the mudification and desliming cylinder, the first mesh plate and the second mesh plate divide the space in the mudification and desliming cylinder into a buffer zone, a mudification zone and a desliming zone from top to bottom, the buffer zone is provided with a fine coal slime discharge port and a coal-water feeding port on the mudification and desliming cylinder, the coal-water feeding pipe is connected with the coal-water feeding port, the stirring wheel is arranged in the mudification zone, and the desliming zone is provided with a coarse coal discharge port and a flushing water port on the mudification and desliming cylinder; The first mesh plate and the second mesh plate each comprise a mounting ring and a flow stabilizing sheet arranged in the ring area of the mounting ring, the flow stabilizing sheet is in a grid shape, a flow stabilizing net is arranged in part of the grids, and the remaining grids are through holes; The first mesh plate and the second mesh plate further comprise a flow slowing plate, the flow slowing plate is arranged on the side of the flow stabilizing sheet facing the mudification zone, and the flow slowing plate is fixedly connected with the side edges of the flow stabilizing net.

2. The lignite treatment method based on pre-slaking and dewatering according to claim 1, characterized in that, The mass ratio of the lignite raw material to water is 1:4-6.

3. The lignite treatment method based on pre-slaking and dewatering according to claim 1, characterized in that, The method further comprises the following step before step 1: The mined lignite is naturally air-dried and then crushed to obtain lignite raw material.

4. The lignite treatment method based on pre-slaking and dewatering according to claim 1, characterized in that, The method further comprises the following step between step 1 and step 2: Particle size analysis is performed on the mudified lignite to obtain the particle size level composition of the mudified lignite.

5. The lignite treatment method based on pre-slaking and dewatering according to claim 1, characterized in that, Step 3 comprises the following steps: Step 31: mixing and wetting the coarse coal and water in a flotation tank to obtain flotation slurry; Step 32: adding a collecting agent to the flotation slurry and fully stirring; Step 33: adding a foaming agent to the flotation slurry containing the collecting agent and fully stirring; Step 34: introducing flotation gas into the flotation tank, scraping the bubbles after aeration, and obtaining flotation clean coal and flotation tailings.

6. The lignite treatment method based on pre-slaking and dewatering according to claim 5, characterized in that, In step 31, the concentration of the flotation slurry is 60-100 g / L.

7. The lignite treatment method based on pre-slaking and dewatering according to claim 5, characterized in that, In step 32, the amount of the collecting agent corresponding to each ton of coarse coal is 1.0-2.0 kg.

8. The lignite treatment method based on pre-slaking and dewatering according to claim 5, characterized in that, In step 33, the amount of the foaming agent corresponding to each ton of coarse coal is 0.2-0.6 kg.

9. The lignite treatment method based on pre-slaking and dewatering according to claim 5, characterized in that, In step 32, the collecting agent comprises a sodium oleate solution and a metal salt solution, and the molar ratio of oleate ions to metal ions is 2:1-1:

2.

10. The lignite treatment method based on pre-slaking and dewatering according to claim 9, characterized in that, In the metal salt solution, the heavy metal ions are divalent metal ions or trivalent metal ions.

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