A separation method of fine particle lignite based on forced slaking-high efficiency desliming

Abstract

The application discloses a sorting method of fine lignite based on forced slurrification-high-efficiency deslurrying, and belongs to the technical field of lignite washing and processing, and aims at solving the problems of large coal slurry water treatment capacity and large viscosity of circulating water in the prior art. The method comprises the following steps: performing dry screening on lignite raw materials, wherein the screened material is first clean coal, and the screened material is directly discharged into a product bin; performing wet screening on the low-ash lump coal, wherein the screened material is second clean coal, and the screened material is directly discharged into the product bin; mixing the low-ash lump coal with water, and performing slurrification treatment on the coal-water mixture, so that pre-slurrification treatment of the lignite is realized, and slurrified granular coal is obtained; performing deslurrying treatment on the slurrified granular coal, so that coarse-grained coal slurry and fine-grained coal slurry are obtained; and performing dewatering treatment on the coarse-grained coal slurry, and the solid product after dewatering is third clean coal. The application can be used for sorting fine lignite.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of lignite washing and dressing, and particularly relates to a lignite separation method based on forced slurrification-high-efficiency deslurring. BACKGROUND

[0002] Lignite has the characteristics of high water, high ash and low calorific value. For the processing and utilization of lignite, the current process flow is relatively simple. After mining, lignite is generally directly sold, and the efficient upgrading of lignite resources has not been realized.

[0003] If a washing and dressing process is used, due to the characteristics of high ash and high water of lignite, a large amount of coal slime will be produced in the water washing process. The coal slime water treatment capacity is large, at the same time, the coal slime content is greatly increased, which will also cause the viscosity of circulating water to rapidly increase, affecting the subsequent separation process. SUMMARY

[0004] In view of the above analysis, the present application aims to provide a lignite separation method based on forced slurrification-high-efficiency deslurring, to solve the problems of large coal slime water treatment capacity and large circulating water viscosity in the prior art.

[0005] The purpose of the present application is mainly realized through the following technical solutions.

[0006] The present application provides a lignite separation method based on forced slurrification-high-efficiency deslurring, comprising the following steps:

[0007] Step 1: dry screening of lignite raw materials, the oversize is the first clean coal, which is directly discharged to the product bin, and the undersize is low-ash lump coal;

[0008] Step 2: wet screening of low-ash lump coal, the oversize is the second clean coal, which is directly discharged to the product bin, and the undersize is low-ash granular coal;

[0009] Step 3: mixing the low-ash granular coal with water, and slurrifying the coal-water mixture to realize the pre-slurrification of lignite, and obtain slurrified granular coal;

[0010] Step 4: deslurring treatment of the slurrified granular coal to obtain coarse granular coal slurry and fine coal slime;

[0011] Step 5: dewatering treatment of the coarse granular coal slurry, and the solid product after dewatering is the third clean coal, which is directly discharged to the product bin, and the first clean coal, the second clean coal and the third clean coal are the final clean coal products.

[0012] Further, in step 3, the slurrification time is 5-30 min.

[0013] Further, in step 1, the total moisture of the lignite raw materials is greater than or equal to 10%, and the screening aperture of the dry screening is 6 mm.

[0014] Further, the total moisture of the lignite raw material is less than 10%, and the sieve size of the dry screening is 3mm.

[0015] Further, in step 2, the sieve size of the wet screening is 1mm.

[0016] Further, in step 5, the dewatering treatment comprises the following steps:

[0017] Step 51: screening and dewatering the coarse coal slurry;

[0018] Step 52: centrifugal dewatering the oversize obtained by the screening and dewatering, and the solid product after the centrifugal dewatering is the third clean coal.

[0019] Further, after step 52, the following steps are further included:

[0020] Step 53: mixing the undersize obtained by the screening and dewatering and the centrifugal liquid obtained by the centrifugal dewatering to obtain a mixed liquid;

[0021] Step 54: using the mixed liquid in the wet screening of step 2 and / or the sliming treatment of step 3.

[0022] Further, in step 4, after the desliming treatment, the following steps are further included:

[0023] Step a: mixing the fine coal slime with a coagulant for flocculation reaction, so that the solid in the fine coal slime combines with the coagulant to form flocculation precipitation;

[0024] Step b: using the overflow of the flocculation reaction in the wet screening of step 2 and / or the sliming treatment of step 3.

[0025] Further, the coagulant is an inorganic coagulant and / or an organic coagulant.

[0026] Further, the mass ratio of the low-ash fine coal to water is 1:4-6.

[0027] Compared with the prior art, the present application can at least achieve the following beneficial effects:

[0028] A) The present application provides a sorting method for fine lignite based on forced sliming-high efficient desliming, which has simple and flexible process flow, does not involve complex process, has small investment, high sorting efficiency and obvious economic benefits.

[0029] B) The application provides a sorting method of fine lignite based on forced argillization-high-efficiency desliming, argillization is a basic characteristic of lignite, and the argillization of clay mineral components in lignite forms high-ash fine mud, which seriously affects the separation efficiency of the washing process, and the application is based on the difference in argillization caused by the different characteristics of useful components and gangue minerals in the lignite raw material, and the lignite raw material is pre-argillized, the high-ash fine mud is hydrated into fine coal slime, and is separated from coarse coal, thereby effectively improving the quality of clean coal.

[0030] C) The application provides a sorting method of fine lignite based on forced argillization-high-efficiency desliming, before argillization, twice screening is carried out, which effectively reduces the treatment amount of subsequent argillization, desliming and dewatering, thereby greatly reducing the water consumption, effectively avoiding the waste of a large amount of water resources caused by the washing process, and in the above-mentioned sorting method of fine lignite, only a small amount of water is needed in the wet screening and argillization process, so that the quality of fine lignite can be improved and the ash content can be reduced, thereby avoiding the problem of low calorific value caused by excessive moisture.

[0031] In the application, the above-mentioned technical solutions can be combined with each other to realize more preferred combination solutions. Other features and advantages of the application will be described in the subsequent description, and some advantages will become apparent from the description, or will be understood by implementing the application. The purpose and other advantages of the application can be realized and obtained through the contents specifically indicated in the description, examples and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application.

[0033] Figure 1 Flow chart of the sorting method of fine lignite based on pre-argillization desliming provided by the application;

[0034] Figure 2 Structure schematic view of the integrated treatment device in the sorting method of fine lignite based on pre-argillization desliming provided by the application;

[0035] Figure 3 Structure schematic view of the upper net plate in the sorting method of fine lignite based on pre-argillization desliming provided by the application;

[0036] Figure 4 Structure schematic view of the coal water feeding pipe in the sorting method of fine lignite based on pre-argillization desliming provided by the application.

[0037] Reference signs:

[0038] 1 - integrated processing cylinder; 2 - discharge chute; 3 - upper screen plate; 31 - steady flow screen; 32 - flushing through hole; 33 - slow flow sub-plate; 4 - lower screen plate; 5 - stirring wheel; 51 - stirring plate; 52 - reinforcing hole; 6 - buffer zone; 7 - mudification zone; 8 - desliming zone; 9 - coal water discharge port; 10 - water inlet; 11 - driving motor; 12 - driving shaft; 13 - coal water feeding pipe; 131 - fixed pipe; 132 - sliding pipe; 133 - operating ring; 14 - coal water feeding port; 15 - first brush; 16 - second brush; 17 - rack; 18 - gear; 19 - mounting rod; 20 - fine coal slime discharge port. DETAILED DESCRIPTION

[0039] The preferred embodiments of the present application will be described in detail below with reference to the drawings, which form a part of this application, and together with the description, illustrate the principles of the application, but are not intended to limit the scope of the application.

[0040] The present application provides a sorting method for fine particle lignite based on forced mudification-high efficiency desliming, referring to Figure 1 , comprising the following steps:

[0041] Step 1: Dry screening of lignite raw materials, the oversize is the first clean coal, directly discharged to the product bin, and the undersize is low-ash lump coal;

[0042] Step 2: Wet screening of low-ash lump coal, the oversize is the second clean coal, directly discharged to the product bin, and the undersize is low-ash particle coal;

[0043] Step 3: Mixing low-ash particle coal with water, and then mudifying the coal-water mixture, the mudification time is 5-30 min, realizing the pre-mudification of lignite, and obtaining mudified particle coal;

[0044] Step 4: Desliming of mudified particle coal, obtaining coarse particle coal slurry and fine particle coal slime;

[0045] Step 5: Dehydration of coarse particle coal slurry, the solid product after dehydration is the third clean coal, directly discharged to the product bin, and the first clean coal, the second clean coal and the third clean coal are the final clean coal products.

[0046] Compared with the prior art, the sorting method for fine lignite based on forced slaking-high efficient desliming provided by the present application has simple and flexible process flow, does not involve complex process, has small investment, high sorting efficiency and obvious economic benefits. On the one hand, the slaking property is a basic property commonly existing in lignite, the clay mineral component in the lignite is slaked to form high-ash fine sludge, which seriously affects the sorting efficiency in the washing and sorting process, the present application is based on the difference in slaking property of the useful components and gangue minerals in the lignite raw material, the lignite raw material is pre-slaked, the high-ash fine sludge (for example, clay mineral) is hydrated into fine coal slurry, which is separated from coarse coal, and the quality of clean coal is effectively improved; on the other hand, before slaking, two screening (dry screening and wet screening) are carried out, which effectively reduces the treatment capacity of subsequent slaking, desliming and dewatering, thereby the water consumption can be greatly reduced, the waste of water resources caused by the washing and sorting process can be effectively avoided, and at the same time, in the above-mentioned sorting method for fine lignite, only a small amount of water is needed in the wet screening and slaking process, so that the quality of fine lignite can be improved and the ash content can be reduced, thereby the problem of low calorific value caused by excessive moisture can be avoided.

[0047] In order to enable the low-ash fine coal to be fully slaked, the mass ratio of the low-ash fine coal to water is 1:4-6 (for example, 1:5).

[0048] In order to further improve the effects of subsequent dry screening, wet screening, slaking, desliming and dewatering, the above-mentioned step 1 further includes the following steps before the step 1:

[0049] The lignite mined from the coal field is naturally dried to remove external moisture, and the lignite raw material is obtained.

[0050] In the above-mentioned step 1, the screening aperture of the dry screening is 3mm or 6mm. It should be noted that if the total moisture of the lignite raw material is greater than or equal to 10%, the screening aperture of the dry screening is 6mm; if the total moisture of the lignite raw material is less than 10%, the screening aperture of the dry screening is 3mm, so that different screening apertures are used for lignite raw materials with different total moisture, which can avoid the blockage of the screen hole.

[0051] Correspondingly, in the above-mentioned step 2, the screening aperture of the wet screening is 1mm.

[0052] In order to enable the coarse coal slurry to be fully dewatered, specifically, in the above-mentioned step 5, the dewatering treatment includes the following steps:

[0053] Step 51: the coarse coal slurry is subjected to screening dewatering;

[0054] Step 52: the oversize material obtained by the screening dewatering is subjected to centrifugal dewatering, and the solid product after centrifugation is the third clean coal.

[0055] In order to make full use of water resources and realize water recycling, the step 52 is followed by the following steps:

[0056] Step 53: mixing the undersize obtained by the screening dehydration and the centrifugal liquid obtained by the centrifugal dehydration to obtain a mixed liquid, since the fine coal slime content in the mixed liquid is small, the mixed liquid is directly recycled as circulating water;

[0057] Step 54: using the mixed liquid in the wet screening of step 2 and / or the sliming treatment of step 3 to realize closed-circuit recycling of washing water.

[0058] Similarly, in order to further utilize water resources and realize water recycling, after the desliming treatment in the step 4, the following steps are included:

[0059] Step a: mixing the fine coal slime with a coagulant to perform a flocculation reaction, so that the solids in the fine coal slime combine with the coagulant to form flocculation precipitate;

[0060] Step b: using the overflow of the flocculation reaction in the wet screening of step 2 and / or the sliming treatment of step 3 to realize closed-circuit recycling of washing water, and discharging the underflow of the flocculation reaction to a tailings pond.

[0061] Exemplarily, the coagulant is an inorganic coagulant and / or an organic coagulant (for example, a natural high-molecular coagulant and an artificially synthesized high-molecular coagulant).

[0062] Alternatively, in the sorting method of the fine lignite, the sliming treatment and the desliming treatment can be performed by an integrated treatment device having the following structure, specifically referring to Figure 2 , which includes a coal-water feeding pipe 13, a sliming and desliming cylinder, and an upper mesh plate 3, a lower mesh plate 4 and a stirring wheel 5 arranged in the sliming and desliming cylinder, the upper mesh plate 3 and the lower mesh plate 4 divide the space in the sliming and desliming cylinder into a buffer zone 6, a sliming zone 7 and a desliming zone 8 from top to bottom, the buffer zone 6 corresponds to the sliming and desliming cylinder, and a fine coal slime discharge port 20 and a coal-water feeding port 14 are arranged on the sliming and desliming cylinder, the coal-water feeding pipe 13 is connected with the coal-water feeding port 14, the stirring wheel 5 is arranged in the sliming zone 7, and the desliming zone 8 corresponds to the sliming and desliming cylinder, and a coal-water discharge port 9 and a water inlet 10 are arranged on the sliming and desliming cylinder.

[0063] In actual application, the coal-water mixture is slowly fed into the buffer zone 6 from the coal-water feed port 14 through the coal-water feed pipe 13. Under the action of the screen plate 3, the flow rate of the coal slurry is further reduced; the coal slurry in the buffer zone 6 is slowly fed into the mudification zone 7 through the gap of the screen plate 3, and the stirring wheel 5 rotates to stir the coal slurry to achieve sufficient mudification of the slurry; the coarse-grained coal slurry after mudification is slowly fed into the demuding zone 8 through the gap of the lower screen plate 4, and flushing water is fed into the mudification zone 7 through the water inlet 10 to flush the muddied coal slurry. Driven by the flushing water, the fine-grained coal slurry with smaller mass is brought to the fine-grained coal slurry discharge port 20 located at the top of the mudification and demuding cylinder and discharged from the fine-grained coal slurry discharge port 20, and the coarse-grained coal with larger mass is discharged from the coal-water discharge port 9 located at the bottom of the mudification and demuding cylinder.

[0064] The integrated treatment device of this structure integrates the slime slurrying and desludging treatment in the inner cavity of the same slime desludging cylinder, and adopts the upper screen plate 3 and the lower screen plate 4 as flow stabilizers, which can control the flow velocity of the slurry, reduce the mutual influence of the buffer zone 6, the slime zone 7 and the desludging zone 8, and realize independent and efficient operation of each area, thereby ensuring the optimization of the separation efficiency of fine-grained coal slime and coarse-grained coal; since the flow direction of the coal slurry is opposite to the flow direction of the flushing water, the upward-flowing flushing water can flush the gaps of the upper screen plate 3 and the lower screen plate 4 and the residue in the slime desludging cylinder, avoiding the fine-grained coal slime from clogging the gaps of the upper screen plate 3, the gaps of the lower screen plate 4 and the slime desludging cylinder, realizing self-cleaning of the integrated treatment device, and ensuring the cleaning efficiency and long-term stable operation of the integrated treatment device.

[0065] In order to facilitate the desludging and discharge of coarse-grained coal, the above-mentioned desludging cylinder includes an integrated processing cylinder 1 and a discharge trough 2. The bottom of the integrated processing cylinder 1 is open, and the discharge trough 2 is buckled at the bottom opening of the integrated processing cylinder 1. The water inlet 10 is arranged on the side wall of the discharge trough 2, and the coal-water discharge port 9 is arranged at the bottom end of the discharge trough 2.

[0066] It can be understood that in order to realize the installation and rotation of the stirring wheel 5, the above-mentioned integrated processing device also includes a drive motor 11 and a drive shaft 12. The stirring wheel 5 is sleeved on the drive shaft 12, and one end of the drive shaft 12 is fixedly connected to the output shaft of the drive motor 11. The drive motor 11 drives the drive shaft 12 and the stirring wheel 5 to rotate synchronously to stir and muddy the coal slurry in the mudification zone 7.

[0067] In order to improve the high shear forced mudification effect, the structure of the stirring wheel 5, specifically, includes a stirring plate 51 and a strengthening hole 52 opened on the stirring plate 51. Through the setting of the strengthening hole 52, bubbles can be generated during the stirring process of the coal slurry, thereby improving the high shear forced mudification effect.

[0068] In order to further improve the high shear forced mudification effect, the number of the reinforcing holes 52 is multiple, the multiple reinforcing holes 52 are arranged along the vertical direction of the stirring plate 51, and the width of the stirring plate 51 and the area of the reinforcing holes 52 gradually increase from top to bottom. 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 stirring 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.

[0069] Considering that the coal water inlet is inevitably deposited with too much coal slime after long-term feeding, and is blocked, in the prior art, for the blockage of the pipeline, the pipeline needs to be disassembled, but this method needs to pause the coal slime mudification and desliming treatment, and the process is complex. In the embodiment, the coal water feeding pipe 13 is a telescopic branch, as shown in Figure 4 , that is, the fixed pipe 131 and the sliding pipe 132 are sequentially connected, the fixed pipe is located outside the mudification and desliming cylinder, the sliding pipe 132 is located inside the mudification and desliming cylinder, the sliding pipe 132 is sleeved on the outer wall of the fixed pipe 131 and is in slidable sealing connection with the fixed pipe 131, the fixed pipe 131 is located outside the mudification and desliming cylinder, the sliding pipe 132 is provided with an operating ring 133 at one end close to the fixed pipe 131, and the operating ring 133 is located outside the mudification and desliming cylinder.

[0070] The above-mentioned integrated treatment device further comprises a feeding pipe cleaning member, the feeding pipe cleaning member comprises a first brush 15, the brush rod end of the first brush 15 is fixedly connected with the fixed pipe 131, the brush end of the first brush 15 protrudes into the sliding pipe 132, and the bristles of the first brush 15 are in contact with the inner wall of the sliding pipe 132, as shown in Figure 4 In this way, the operator can move the sliding pipe 132 relative to the fixed pipe 131 by reciprocating the operating ring 133, and the first brush 15 can brush and wash the inner wall of the sliding pipe 132.

[0071] In order to brush and wash the discharge end of the sliding pipe 132, the above-mentioned feeding pipe cleaning member further comprises a second brush 16, a rack 17, a gear 18 and a mounting rod 19, one end of the rack 17 is fixedly connected with the inner wall of the mudification and desliming cylinder, the other end is provided in a suspended manner, the gear 18 is in rotary connection with the outer wall of the sliding pipe 132 through a gear shaft, the gear 18 is in perpendicular engagement with the rack 17, one end of the mounting rod 19 is fixedly connected with the gear 18, the other end of the mounting rod 19 is fixedly connected with the brush rod end of the second brush 16, and the bristles of the second brush 16 are in contact with the discharge end of the sliding pipe 132. In this way, when the sliding pipe 132 reciprocates up and down, the gear 18 is driven to reciprocate on the rack 17, and then the gear 18 is driven to rotate and the mounting rod 19 is driven to swing, so that the bristles reciprocate relative to the discharge end of the sliding pipe 132, and the discharge end of the sliding pipe 132 is brushed and washed.

[0072] For the structure of the upper screen plate 3 and the lower screen plate 4, see Figure 3 which comprises a mounting ring and a flow stabilizing sheet arranged in the area within the ring of the mounting ring, the flow stabilizing sheet is in the shape of a grid, part of the grid is provided with a flow stabilizing net 31, and the remaining grid is a flushing through hole 32, wherein the flushing through hole 32 can ensure that the flushing water passes smoothly and flows upward quickly to flush the coal slurry in the desliming area 8, the mudification area 7 and the buffer area 6, ensuring the desliming efficiency and effect, and the flow stabilizing net 31 can appropriately isolate the desliming area 8, the mudification 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.

[0073] Exemplarily, see Figure 3 The shapes of the flushing through hole 32 and the flow stabilizing net 31 are both rectangular, and a plurality of flushing through holes 32 and a plurality of flow stabilizing nets 31 are arranged alternately, that is, the flow stabilizing net 31 is arranged in every other grid hole.

[0074] 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 upper screen plate 3 and lower screen plate 4 further comprise a flow slowing sub-plate 33, which is arranged on the side of the flow stabilizing sheet facing the mudification area 7. From the dual perspectives of flow stabilization and flushing water flow, the flow slowing sub-plate 33 is fixedly connected to the side 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 mudification and desliming cylinder, and through the arrangement of the flow slowing sub-plate 33, the fluctuation in the mudification 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, and ensuring the uniform distribution of the coal slurry during the flow process.

[0075] Embodiment 1

[0076] The separation method of fine lignite based on forced mudification-high efficiency desliming in this embodiment comprises the following steps:

[0077] Step A: Dry the lignite sample mined from the Yimin coalfield to remove external moisture. According to the high moisture content of the Yimin lignite sample, the lignite raw material is subjected to 6mm dry screening treatment to obtain products of >6mm and <6mm particle size, and the product of >6mm particle size from step A is directly discharged into the product bin to obtain low-ash lump coal.

[0078] Step B: The undersize <6mm product from step A is subjected to 1mm wet screening treatment to obtain oversize >1mm and undersize <1mm, and the product of >1mm particle size is directly discharged into the product bin to obtain low-ash grain coal.

[0079] Step C: The <1mm undersize in Step B is subjected to mud treatment, the stirring wheel speed is adjusted to 2000 rpm, the timer is started, and the mud treatment time lasts for 10 min.

[0080] The corresponding products are subjected to sieve size analysis, the -0.045mm proportion before mud treatment is 33.72%, and the ash content is 24.83%; the -0.045mm proportion after mud treatment is 46.30%, and the ash content is 25.03%.

[0081] Step D: The mud-treated granular coal is subjected to desliming treatment, the ash content of the entire feed is reduced from 18.56% to 12.01%, and the ash content of the 0.5-0.25mm size fraction is 9.59%, realizing the ash reduction and quality improvement of lignite;

[0082] The overflow of the desliming treatment is fed into a thickener, concentrated in the thickener, and flocculated by adding coagulants and other reagents. The obtained overflow is discharged to a circulating water pool and used as 1mm classification spray water and desliming water, realizing water resource recycling; the obtained underflow is discharged to a tailings pond as gangue product.

[0083] Step E: The coarse coal slurry is subjected to sieve dewatering, the sieve oversize of the sieve dewatering is fed into a centrifuge for dewatering, the product after centrifuge dewatering is used as clean coal product, and the centrifugal liquid and the sieve undersize of the sieve dewatering are fed into a thickener.

[0084] Step F: The centrifugal liquid and the sieve undersize of the sieve dewatering are directly used as circulating water for 1mm classification spray water and desliming water, realizing closed-circuit circulation of washing water.

[0085] The specific particle size distribution after forced mud treatment and high-efficiency desliming is shown in Table 1.

[0086] Table 1 Particle size distribution of Example 1

[0087]

[0088] Example 2

[0089] The difference between the lignite separation method based on forced mud treatment and high-efficiency desliming of this example and Example 1 is that:

[0090] The mud treatment time of Step C is adjusted to 5 min.

[0091] The corresponding products are subjected to sieve size analysis, the -0.045mm proportion before mud treatment is 33.72%, and the ash content is 24.83%; the -0.045mm proportion after mud treatment is 42.72%, and the ash content is 24.43%.

[0092] In step D, the ash content of the whole feedstock was reduced from 18.56% to 12.94% after desliming treatment, and the ash content of the 0.5-0.25 mm size fraction was 9.91%, realizing the ash reduction and quality improvement of lignite.

[0093] The particle size distribution after forced sludging and high-efficiency desliming is shown in Table 2.

[0094] Table 2 Particle size distribution of Example 2

[0095]

[0096] The above merely provides the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any changes or replacements within the technical scope disclosed by the present application can be easily conceived by those skilled in the art, which should be encompassed within the protection scope of the present application.

Claims

1. A method for separating fine-grained lignite based on forced mudification and efficient desludging, characterized in that: The following steps are involved: Step 1: Dry screen the lignite raw material. The oversize is the first clean coal, which is directly discharged into the product bin. The undersize is low-ash lump coal. If the total moisture content of the lignite raw material is greater than or equal to 10%, the sieve aperture of the dry screening is 6mm; if the total moisture content of the lignite raw material is less than 10%, the sieve aperture of the dry screening is 3mm. Step 2: Wet-screen the low-ash lump coal. The oversize is the second clean coal, which is directly discharged into the product bin. The undersize is the low-ash granular coal. The sieve aperture of the wet screening is 1 mm. Step 3: After mixing the low-ash coal particles with water, the coal-water mixture is subjected to a mud treatment to achieve pre-mud treatment of the lignite to obtain muddy coal particles, wherein the mass ratio of the low-ash coal particles to water is 1:4-6; Step 4: Desludging the muddy coal particles to obtain coarse coal slurry and fine coal slime; Step 5: Dehydrate the coarse coal slurry. The solid product after dehydration is the third clean coal, which is directly discharged into the product bin. The first clean coal, second clean coal and third clean coal are the final clean coal products. In step 5, the dehydration process includes the following steps: Step 51: screening and dehydrating the coarse coal slurry; Step 52: centrifugally dehydrate the oversize obtained by screening and dehydration, and the solid product after centrifugation is the third clean coal; Step 53: mixing the undersize obtained by sieving and dehydrating with the centrifuge obtained by centrifugal dehydration to obtain a mixed solution; Step 54: using the mixed liquid for wet screening in step 2 and / or mud treatment in step 3; In the step 4, the desludging process further includes the following steps: Step a: mixing the fine coal slime with a coagulant to carry out a flocculation reaction, so that the solids in the fine coal slime combine with the coagulant to form a flocculated precipitate; Step b: using the upper overflow of the flocculation reaction for the wet screening in step 2 and / or the mud treatment in step 3.

2. The method for separating fine-grained lignite based on forced mudification and efficient desludging according to claim 1, characterized in that: In step 3, the mud treatment time is 5 to 30 minutes.

3. The method for separating fine-grained lignite based on forced mudification and efficient desludging according to claim 1, characterized in that: The coagulant is an inorganic coagulant and / or an organic coagulant.

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