A wide particle size coal slime high recovery rate flotation system and method

Abstract

The present application provides a kind of wide particle size grade slime high recovery rate flotation system, it includes flotation device, flotation device includes flotation tank, ore feeding port, fine particle overflow collection tank, froth clean coal collection tank and partition, the number of partition is two, two partitions divide the upper region of flotation tank into adjacent three regions, three regions are first bubble zone, overflow zone and second bubble zone respectively, the number of froth clean coal collection tank is two, two froth clean coal collection tanks are adjacent with the fine particle overflow collection tank, and two froth clean coal collection tanks are respectively connected with corresponding first bubble zone and second bubble zone.The present application also discloses a kind of wide particle size grade slime high recovery rate flotation method.The present application is improved by new type flotation equipment design, under the condition of guaranteeing recovery rate and ash content, coarse coal and fine coal can be simultaneously floated out using one flotation equipment, additional needs brought by the existing process particle size grade flotation is reduced.

Description

Technical Field

[0001] This invention relates to the field of mineral sorting and processing technology, specifically to a flotation system and method for high recovery of wide-particle-size coal slime. Background Technology

[0002] With increasingly complex coal mining conditions and the widespread use of large-scale mechanized mining equipment, the coal slime content in coal preparation plants has increased. Currently, coal preparation plants mainly reduce the processing volume of flotation and coal slime water treatment by increasing the amount of coarse coal slime recovery and separation equipment and processes, thereby improving the coal slime recovery rate. However, this separation process is relatively long. Furthermore, for some coal preparation plants with low coarse coal slime content, adding separate recovery and separation processes leads to increased production costs and reduced efficiency. In addition, the recovery of coarse and fine particles requires completely different flotation hydrodynamic conditions. Fine particles require high stirring intensity and microbubbles to improve the collision and adhesion efficiency of fine particles; while coarse particles require lower stirring intensity and relatively large bubbles to ensure that coarse particles float and do not fall off the bubbles. There is a certain contradiction between the two, making it difficult for existing flotation equipment to simultaneously achieve the flotation recovery of coarse and fine particles. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-recovery flotation system and method for wide-particle-size coal slime. Through improved design of a novel flotation device, it achieves the simultaneous flotation of coarse and fine coal using a single flotation unit, while ensuring recovery rate and ash content, thus reducing the additional requirements of particle-size flotation in existing processes.

[0004] To address the aforementioned problems, this invention provides a high-recovery flotation system for wide-particle-size coal slime, characterized by comprising a flotation device. The flotation device includes a flotation cell, a feed inlet, a fine-particle overflow collection tank, a frothy clean coal collection tank, and baffles. The baffles are disposed in the upper part of the flotation cell, with one end connected to one side of the flotation cell and the other end connected to the other side. Two baffles are used, dividing the upper region of the flotation cell into three adjacent regions, which are respectively: a first... The flotation cell includes a froth zone, an overflow zone, and a second froth zone. The feed inlet is located at the inlet of the overflow zone and is connected to the overflow zone. The fine particle overflow collection trough is located at the outlet of the overflow zone and is connected to the overflow zone. There are two frothed coal collection troughs, both of which are located on the flotation cell and are adjacent to the fine particle overflow collection trough. The two frothed coal collection troughs are respectively connected to the corresponding first froth zone and second froth zone.

[0005] The above-mentioned wide-particle-size coal slime high-recovery flotation system is characterized in that: the flotation device further includes a false bottom, an impeller stirring mechanism, a flow stabilizer plate, a frother pipe, a suction pipe, a stator guide plate, a tailings pipe, and a foam scraper. The false bottom is located at the lower part of the flotation cell, the impeller stirring mechanism is located above the false bottom, and there are multiple flow stabilizers evenly arranged around the center of the impeller stirring mechanism. The suction pipe is located at the bottom of the impeller stirring mechanism, and the lower end of the frother pipe is connected to the suction pipe. The stator guide plate is located at the bottom of the impeller stirring mechanism, the tailings pipe is located at the bottom of the flotation cell, and the tailings pipe is used to discharge the tailings after separation in the flotation cell. The foam scraper is located above the first foam zone and the second foam zone, and the foam scraper is used to collect the clean coal flotated in the first foam zone and the second foam zone into a foam clean coal collection tank.

[0006] The above-mentioned wide-particle-size coal slime high-recovery flotation system is characterized in that: the wide-particle-size coal slime high-recovery flotation system further includes a slurry mixing tank, the outlet of the slurry mixing tank is connected to the feed port through a pipeline, and the slurry mixing tank is used to stir and mix the coal slime water and flotation reagents.

[0007] The above-mentioned wide-particle-size coal slime high-recovery flotation system is characterized in that: the wide-particle-size coal slime high-recovery flotation system further includes a centrifugal dewatering machine, the feed inlet of which is connected to a foamed clean coal collection tank.

[0008] The above-mentioned wide-particle-size coal slime high-recovery flotation system is characterized in that: the wide-particle-size coal slime high-recovery flotation system further includes a flotation column, the feed inlet of which is connected to the filtrate outlet of a centrifugal dewatering machine and a fine particle overflow collection tank.

[0009] The above-mentioned wide-particle-size coal slime high-recovery flotation system is characterized in that: the wide-particle-size coal slime high-recovery flotation system further includes a diaphragm filter press, the feed inlet of which is connected to the concentrate outlet of the flotation column.

[0010] The above-mentioned wide-particle-size coal slime high-recovery flotation system is characterized in that: the wide-particle-size coal slime high-recovery flotation system further includes a thickener, the feed inlet of which is connected to the tailings outlet of the flotation column and the tailings pipeline.

[0011] This invention also discloses a flotation method for high recovery of wide-particle-size coal slime, characterized by comprising the following steps:

[0012] Step 1: Slurry preparation. Coal slurry is introduced into the slurry mixing tank at a predetermined flow rate. Flotation reagents are added to the slurry mixing tank in a predetermined ratio. The stirring mechanism in the slurry mixing tank stirs and mixes the coal slurry and flotation reagents at a preset speed to achieve selective flocculation and agglomeration of gangue particles in the slurry.

[0013] Step 2: First-stage flotation separation. The mixed slurry from Step 1 is fed into the flotation device through the feed port and floated. The flotation in the flotation device is a first-stage flotation.

[0014] Step 3: Clean coal dewatering. The clean coal in the first flotation froth zone of Step 2 enters the centrifugal dewatering machine for dewatering. The dewatered product is part of the final clean coal product. The centrifugal liquid and the clean coal in the overflow zone of the flotation unit are combined and enter the flotation column for fine selection.

[0015] Step 4: Second-stage flotation column cleaning. The second-stage flotation uses the centrifugal liquid generated from the dewatering of the concentrate in the overflow zone and the concentrate in the froth zone of the first-stage flotation unit as raw material, and further removes gangue particles to ensure that the ash content of the final clean coal product is further reduced.

[0016] Step 5: Second-stage clean coal dewatering. The clean coal product obtained from the second-stage flotation column enters the diaphragm filter press for dewatering treatment and then is fed into the final clean coal product to obtain all clean coal products. The water removed from the diaphragm filter press is reused as circulating water.

[0017] Step 6: Tailings dewatering. All tailings from the second-stage flotation column and the first-stage flotation unit are fed into the thickener for concentration to obtain all tailings products. The effluent from the thickener is reused as circulating water.

[0018] The above-mentioned flotation method for high recovery of wide-particle-size coal slime is characterized in that: the flotation reagents in step one include modifiers, dispersants and flocculants.

[0019] The above-mentioned flotation method for high recovery of wide-particle-size coal slime is characterized in that: the specific separation steps of the first-stage flotation equipment in step one include:

[0020] The slurry prepared in step one is transported to the overflow zone of the flotation cell through the feed port at a predetermined flow rate. Small coal particles are directly overflowed by the water flow in the water surface layer and enter the fine particle overflow collection tank to become the overflow zone concentrate. Meanwhile, small gangue particles in the slurry are flocculated and sink from the flow layer to the flotation zone to participate in the flotation process. Large coal particles and gangue particles in the slurry also sink from the flow layer together to participate in the subsequent flotation.

[0021] The impeller agitator rotates and generates negative pressure, drawing in air, collector, and frother from the air and frother pipes. It cuts the air into appropriately sized bubbles, which then rise through the false bottom and flow stabilizer to the first or second foam zone. In the slurry-air mixing zone, the suction pipe and stator guide plate draw in slurry for mixing and circulation, allowing coarse coal particles to be mineralized. These particles collide with appropriately sized bubbles, adhere, and float to the flotation zone and foam zone, where they are finally scraped out by the foam scraper to the foam concentrate collection tank, becoming foam zone concentrate. Gangue particles are then discharged into the tailings pipe under the action of the flow field.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. This invention, through the design of a two-stage fine coal washing process, can ensure that the recovery rate of clean coal in the slurry is close to or even exceeds the recovery rate after strict particle size classification; at the same time, different flotation processes can be set according to different particle size grades to achieve the maximum recovery rate of clean coal of different particle size grades.

[0024] 2. This invention improves the design of a new flotation device, which can simultaneously float coarse and fine coal using a single flotation device while ensuring recovery rate and ash content. This effectively broadens the flotation range, expands the coal slime particle size to 1mm, and reduces the additional need for particle size fractional flotation in existing processes.

[0025] 3. By simplifying the existing flotation process, this invention can save the need for a large number of flotation machines and transportation pipelines in the design and construction of coal preparation plants. In addition, the equipment required for the process occupies a smaller area than the existing process equipment, which can save more resources and bring greater economic benefits.

[0026] The invention will now be described in further detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0027] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0028] Figure 1 This is a front view schematic diagram of the structural principle of the flotation device in an embodiment of the present invention.

[0029] Figure 2 This is a left-side view of the structural principle of the flotation device in an embodiment of the present invention.

[0030] Figure 3 This is a schematic diagram showing the position and connection relationship between the feed inlet, fine particle overflow collection tank, frothy coal collection tank, and the baffle plate and flotation cell in the flotation device of this embodiment of the invention.

[0031] Figure 4 This is a flowchart illustrating the structural principle of the wide-particle-size coal slime high-recovery flotation system in an embodiment of the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] 10—Flotation device; 11—Flotation cell; 12—Feed inlet; 13—Fine particle overflow collection tank;

[0034] 14—Foamed coal collection trough; 15—Baffle plate; 16—Tailings pipeline; 17—False bottom;

[0035] 18—Impeller stirring mechanism; 19—Flow stabilizer plate; 20—Foaming agent pipe; 21—Suction pipe;

[0036] 22—Stator guide plate; 23—First foam zone; 24—Overflow zone; 25—Second foam zone;

[0037] 30—Preparation tank; 31—Centrifugal dewatering machine; 32—Flotation column; 33—Diaphragm filter press;

[0038] 34—Concentrator. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0040] like Figures 1 to 4As shown, this invention discloses a high-recovery flotation system for wide-particle-size coal slime, characterized by comprising a flotation device 10. The flotation device 10 includes a flotation cell 11, a feed inlet 12, a fine-particle overflow collection tank 13, a frothy clean coal collection tank 14, and baffles 15. The baffles 15 are disposed in the upper part of the flotation cell 11. One end of the baffle 15 is connected to one side of the flotation cell 11, and the other end of the baffle 15 is connected to the other side of the flotation cell 11. There are two baffles 15, which divide the upper region of the flotation cell 11 into three adjacent regions, namely, a first frothy zone 23, a second frothy zone 24, and a third frothy zone 25. The system includes an overflow zone 24 and a second foam zone 25. The feed inlet 12 is located at the inlet of the overflow zone 24 and is connected to the overflow zone 24. The fine particle overflow collection tank 13 is located at the outlet of the overflow zone 24 and is connected to the overflow zone 24. There are two foamed coal collection tanks 14, both of which are located on the flotation cell 11 and are adjacent to the fine particle overflow collection tank 13. The two foamed coal collection tanks 14 are respectively connected to the corresponding first foam zone 23 and second foam zone 25.

[0041] In this embodiment, two opposing baffles 15 are provided in the flotation device 10. The prepared slurry enters the overflow zone 24 from the upper part of one side of the flotation cell 11 through the feed port 12. Since the slurry has a certain flow velocity, small coal particles are affected by the water flow in the water surface flow layer and enter the fine particle overflow collection tank 13 from the overflow port on the other side of the flotation cell 11, becoming the overflow zone concentrate. Small gangue particles in the slurry, under the effect of flocculation, sink from the flow layer to the flotation zone and participate in the flotation process. Larger coal and gangue particles in the slurry also sink from the flow layer and participate in subsequent flotation. The subsequent flotation principle is the same as existing flotation technology. Bubbles at the bottom of flotation cell 11 rise and collide with and adhere to the descending medium and large coal and gangue particles, and float to the flotation zone and foam zone. Finally, they are scraped out by the foam scraper to the foam concentrate collection tank 14 to become foam zone concentrate. The gangue particles are finally discharged into the tailings pipe 16 under the action of the flow field. The wide-particle-size coal slime mentioned in this invention refers to coal slime with a particle size range of less than 1 mm. By improving the design of the new flotation equipment, it is possible to use a single flotation device to simultaneously float coarse and fine coal while ensuring recovery rate and ash content. This effectively broadens the flotation range and reduces the additional need for particle size-based flotation in existing processes.

[0042] like Figures 1 to 4 As shown, in this embodiment, the lower part of the area separated by the two oppositely arranged partitions 15 is inverted cone-shaped, which is conducive to the rising foam at the bottom carrying the fine coal into the first foam area 23 and the second foam area 25 on both sides of the overflow area 24.

[0043] like Figure 1 and Figure 2 As shown, the flotation device 10 also includes a false bottom 17, an impeller stirring mechanism 18, a flow stabilizer 19, a frother pipe 20, a suction pipe 21, a stator guide plate 22, a tailings pipe 16, and a froth scraper. The false bottom 17 is located at the lower part of the flotation cell 11, and the impeller stirring mechanism 18 is located above the false bottom 17. Multiple flow stabilizers 19 are evenly arranged around the center of the impeller stirring mechanism 18. The suction pipe 21 is located within the impeller stirring mechanism 18. At the bottom of 8, the lower end of the foaming agent pipe 20 is connected to the suction pipe 21. The stator guide plate 22 is located at the bottom of the impeller stirring mechanism 18. The tailings pipe 16 is located at the bottom of the flotation cell 11 and is used to discharge the tailings after separation in the flotation cell 11. The foam scraper is located above the first foam zone 23 and the second foam zone 25 and is used to collect the clean coal flotated in the first foam zone 23 and the second foam zone 25 into the foam clean coal collection tank 14.

[0044] In this embodiment, the impeller stirring mechanism 18 is the same as the stirring mechanism in the impeller stirring flotation cell in the prior art. The stirring shaft is driven by a motor, and the stirring shaft drives the stirring blades to stir. The stirring blades rotate and generate negative pressure, drawing in air, collector and frother from the air and frother pipe 20, and cutting the air into appropriately sized bubbles. Finally, the bubbles rise through the false bottom 17 and the flow stabilizer 19 to the first foam zone 23 or the second foam zone 25. In the slurry-air mixing zone, the slurry is drawn in through the suction pipe 21 and the stator guide plate 22 for mixing and circulation, so that the coarse coal particles are mineralized and collide with appropriately sized bubbles, attach and float to the flotation zone and foam zone. Finally, they are scraped out by the foam scraper to the foam concentrate collection tank 14 to become foam zone concentrate. The gangue particles are finally discharged into the tailings pipe 16 under the action of the flow field.

[0045] like Figure 4 As shown, the wide-particle-size coal slime high-recovery flotation system also includes a slurry mixing tank 30. The outlet of the slurry mixing tank 30 is connected to the feed inlet 12 through a pipeline, and the slurry mixing tank 30 is used to stir and mix the coal slime water and flotation reagents.

[0046] In this embodiment, the mixing tank 30 is equipped with a stirring device, which is mainly used for stirring and mixing coal slurry and flotation reagents.

[0047] like Figure 4 As shown, the wide-particle-size coal slime high-recovery flotation system also includes a centrifugal dewatering machine 31, the inlet of which is connected to the foamed coal collection tank 14.

[0048] In this embodiment, the centrifugal dewatering machine 31 is mainly used to dewater the clean coal collected in the foam clean coal collection tank 14. The dewatered product is part of the final clean coal product. The centrifugal liquid and the clean coal in the overflow area of ​​the flotation device 10 are combined and enter the flotation column 32 for further refining.

[0049] like Figure 4 As shown, the wide-particle-size coal slime high-recovery flotation system also includes a flotation column 32, the feed inlet of which is connected to the filtrate outlet of the centrifugal dewatering machine 31 and the fine particle overflow collection tank 13.

[0050] In this embodiment, the flotation column 32 serves as a two-stage flotation process. It uses the centrifugal liquid generated from the dewatering of the concentrate in the overflow zone and the concentrate in the froth zone of the first-stage flotation unit 10 as raw material, further removing gangue particles to ensure a further reduction in the ash content of the final clean coal product. This ensures a high recovery rate for the final clean coal product and reduces the ash content in the product.

[0051] like Figure 4 As shown, the wide-particle-size coal slime high-recovery flotation system also includes a diaphragm filter press 33, the feed inlet of which is connected to the concentrate outlet of the flotation column 32.

[0052] In this embodiment, the diaphragm filter press 33 is mainly used to dewater the clean coal product obtained from the two-stage flotation column. The dewatered product is then fed into the final clean coal product to obtain all the clean coal products. The water removed from the diaphragm filter press 33 can be reused as circulating water to ensure closed-loop circulation of the wash water.

[0053] like Figure 4 As shown, the wide-particle-size coal slime high-recovery flotation system also includes a thickener 34, the feed inlet of which is connected to the tailings outlet of the flotation column 32 and the tailings pipeline 16.

[0054] In this embodiment, the thickener 34 is mainly used to thicken the tailings from the second-stage flotation column and the first-stage flotation unit 10 to obtain all the tailings products. Simultaneously, the bottom runoff from the thickener 34 can be reused as circulating water, ensuring closed-loop circulation of the wash water and guaranteeing that this flotation process will not impact local water sources or other environmental factors.

[0055] This invention also discloses a high-recovery flotation method for wide-particle-size coal slime, characterized in that the high-recovery flotation method for wide-particle-size coal slime is based on the above-mentioned high-recovery flotation system for wide-particle-size coal slime, and specifically includes the following steps:

[0056] Step 1: Slurry preparation. Coal slurry is introduced into the mixing tank 30 at a predetermined flow rate. Flotation reagents are added to the mixing tank 30 in a predetermined ratio. The stirring mechanism in the mixing tank 30 stirs and mixes the coal slurry and flotation reagents at a preset speed to achieve selective flocculation and agglomeration of gangue particles in the slurry.

[0057] Step 2: The first-stage flotation equipment separates the slurry. The slurry prepared in Step 1 in the slurry preparation tank 30 is transported to the overflow zone 24 in the flotation cell 11 through the feed port 12 at a predetermined flow rate. Small coal particles are directly overflowed by the water flow in the water surface layer and enter the fine particle overflow collection tank 13 to become the overflow zone concentrate. Meanwhile, small gangue particles in the slurry are flocculated and sink from the flow layer to the flotation zone to participate in the flotation process. Large coal particles and gangue particles in the slurry also sink from the flow layer together to participate in the subsequent flotation.

[0058] The impeller stirring mechanism 18 rotates and generates negative pressure, drawing in air, collector and foaming agent from the air and foaming agent pipe 20, and cutting the air into appropriately sized bubbles. Finally, the bubbles rise through the false bottom 17 and the flow stabilizer 19 to the first foam zone 23 or the second foam zone 25. In the slurry-air mixing zone, the slurry is drawn in through the suction pipe 21 and the stator guide plate 22 for mixing and circulation, so that the coarse coal particles are mineralized and collide with appropriately sized bubbles, attach and float to the flotation zone and foam zone. Finally, they are scraped out by the foam scraper to the foam concentrate collection tank 14 to become foam zone concentrate. The gangue particles are finally discharged into the tailings pipe 16 under the action of the flow field.

[0059] Step 3: Clean coal dewatering. The clean coal in the first flotation froth zone of Step 2 enters the centrifugal dewatering machine 31 for dewatering. The dewatered product is part of the final clean coal product. The centrifugal liquid and the clean coal in the overflow zone of the flotation device 10 are combined and enter the flotation column 32 for fine selection.

[0060] Step 4: Second-stage flotation column cleaning. The second-stage flotation uses the centrifugal liquid generated from the dewatering of the concentrate in the overflow zone and the concentrate in the froth zone of the first-stage flotation unit 10 as raw material, and further removes gangue particles to ensure that the ash content of the final clean coal product is further reduced.

[0061] Step 5: Second-stage clean coal dewatering. The clean coal product obtained from the second-stage flotation column enters the diaphragm filter press 33 for dewatering treatment and then passes through the final clean coal product to obtain all clean coal products. The water removed from the diaphragm filter press 33 is reused as circulating water.

[0062] Step 6: Tailings dewatering. All tailings from the second-stage flotation column and the first-stage flotation unit 10 are fed into thickener 34 for thickening to obtain all tailings products. The bottom water of thickener 34 is reused as circulating water.

[0063] In step one of this embodiment, the slurry, under the action of specific modifiers, dispersants, and flocculants, undergoes interfacial regulation on the surfaces of gangue and coal particles. This causes the interfacial forces on the gangue surface to manifest as attraction, resulting in flocculation, while the interfacial forces on the coal particles manifest as repulsion, leading to dispersion and thus enhancing selective flocculation. Controlling the rotation speed of the mixing mechanism in the mixing tank generates a specific fluid force field and shear rate. According to relevant research, because coal flocs are larger than quartz flocs, at a constant shear rate, coal flocs are simultaneously subjected to shearing and stretching effects from microscopic vortices, making them more easily destroyed. Quartz flocs, on the other hand, are only subjected to shearing effects from microscopic vortices, resulting in less destruction. By adjusting the shear rate, the size of the microscopic vortices in the flow field can be controlled, thereby causing different degrees of destruction to both coal and quartz flocs and achieving selective flocculation of quartz. The desired selective flocculation effect of gangue is achieved through interfacial regulation and flow field adjustment.

[0064] In step two of this embodiment, the flotation cell 11 can be divided into four areas according to their functions: a froth zone, an overflow zone, a flotation zone, and a slurry-gas mixing zone. The feed inlet 12 is located at the inlet of the overflow zone, and the fine-particle overflow collection tank 13 is located at the outlet of the overflow zone, collecting a large amount of overflow water and coal particles. A flow layer exists at the water surface in the overflow zone. Particles in the flow layer are subjected to the force of the water flow and gravity. If the particles do not detach from the flow layer, they are considered to become overflow products and enter the fine-particle overflow collection tank 13. If the particles detach from the flow layer, they will sink to the flotation zone and the slurry-gas mixing zone to participate in subsequent flotation. Each of the two froth zones is equipped with a froth scraper, which can scrape the froth to the froth clean coal collection tank. A flushing device can be appropriately added to the top of the two froth zones to further reduce the ash content of the clean coal in the froth zone. In the slurry-air mixing zone, a mechanical stirring mechanism generates negative pressure to draw air in through the suction pipe 21. The air intake is increased or controlled by an air pump. Collectors and frothers required for flotation are added through the dosing pipe, causing the slurry to circulate in the stator-rotor system and adhere to the air bubbles to complete mineralization. Large coal particles that have completed mineralization in the flotation section rise to the froth layer to complete one stage of flotation.

[0065] In this embodiment, the flotation feed is connected to the mixing tank 30, and the flotation device 10 is equipped with a baffle 15 to divide the flotation flotation zone into two areas: the overflow zone 24 and the flotation zone. The flotation zone includes a first flotation zone 23 and a second flotation zone 25. Fine-grained low-ash products enter the overflow zone 24 through the feed inlet 12 and flow towards the fine-grained overflow collection tank 13 with the horizontal flow layer formed by the water flow in the overflow zone 24. Coarse particles sink into the impeller agitated flotation cell under their own gravity for flotation, collide with the rising bubbles, and finally the foam formed by this part of the clean coal is scraped out in the flotation zone.

[0066] Then, the concentrate from the froth zone of the flotation unit 10 flows into the centrifugal dewatering machine 31, the concentrate from the overflow zone enters the flotation column 32 for fine selection, the tailings flow into the thickener 34, the filtered product of the centrifugal dewatering machine 31 is discharged as concentrate, the centrifugal liquid from the centrifugal dewatering machine 31 and the concentrate from the overflow zone of the flotation unit 10 are combined and flow into the flotation column 32, the concentrate from the flotation column 32 flows into the diaphragm filter press 33, the tailings from the flotation column 32 flow into the thickener 34, the filter material from the diaphragm filter press 33 is discharged as concentrate, the filter water from the diaphragm filter press 33 flows into the circulating water for subsequent separation, the filtered product of the thickener 34 is tailings, the concentrated water flows into the circulating water for subsequent separation.

[0067] In this embodiment, the slurry processed in the mixing tank is transported to the flotation device 10 at a certain flow rate. The concentrate in the froth zone of the flotation device 10 enters the centrifugal dewatering machine 31 for dewatering. The concentrate in the overflow zone of the flotation device 10 and the centrifugal liquid enter the flotation column 32 for fine cleaning. The flotation column 32 uses the centrifugal liquid generated from the dewatering of the concentrate in the overflow zone and the concentrate in the froth zone of the flotation device 10 as raw material. The clean coal product obtained from the flotation column 32 enters the diaphragm filter press 33 for dewatering and then passes through the final clean coal product to obtain all the clean coal products. The water removed from the diaphragm filter press 33 is reused as circulating water. The tailings from the flotation column 32 and the tailings from the flotation device 10 all enter the thickener 34 for thickening to obtain all the tailings products. The bottom water of the thickener 34 is reused as circulating water.

[0068] This invention improves the recovery rate by more than 5% through a two-stage fine-grained process: a first-stage flotation in the flotation device 10 and a second-stage flotation in the flotation column 32. This ensures that the recovery rate of clean coal in the feed slurry is close to or even exceeds the maximum recovery rate of clean coal of different particle sizes achieved by strictly classifying by particle size and setting different flotation processes according to different particle size grades. It enables the simultaneous flotation of coarse and fine coal using a single flotation device while ensuring recovery rate and ash content. This reduces the additional need for particle size-graded flotation in existing processes. By simplifying the existing flotation process, it can save the need for a large number of flotation machines and transportation pipelines in the design and construction of coal preparation plants. The equipment footprint required for this process is smaller than that of existing processes, saving more resources and bringing greater economic benefits.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A flotation system for high recovery of coal slime with a wide particle size range, characterized in that, The flotation apparatus (10) includes a flotation cell (11), a feed inlet (12), a fine particle overflow collection tank (13), a frothy coal collection tank (14), and baffles (15). The baffles (15) are located in the upper part of the flotation cell (11). One end of the baffle (15) is connected to one side of the flotation cell (11), and the other end is connected to the other side of the flotation cell (11). There are two baffles (15), which divide the upper part of the flotation cell (11) into three adjacent areas: a first frothy zone (23), an overflow zone (24), and a second frothy zone (25). The feed inlet (12) is... At the inlet of the overflow zone (24), and the feed port (12) is connected to the overflow zone (24), the fine particle overflow collection tank (13) is located at the outlet of the overflow zone (24), and the fine particle overflow collection tank (13) is connected to the overflow zone (24). There are two foamed coal collection tanks (14), both of which are located on the flotation cell (11). Both of the foamed coal collection tanks (14) are adjacent to the fine particle overflow collection tank (13), and the two foamed coal collection tanks (14) are connected to the corresponding first foam zone (23) and second foam zone (25) respectively. The lower part of the area separated by the two opposing partitions (15) is inverted cone-shaped.

2. The wide-particle-size coal slime high-recovery flotation system according to claim 1, characterized in that: The flotation device (10) also includes a false bottom (17), an impeller stirring mechanism (18), a flow stabilizer (19), a frother pipe (20), a suction pipe (21), a stator guide plate (22), a tailings pipe (16), and a foam scraper. The false bottom (17) is located at the lower part of the flotation cell (11), and the impeller stirring mechanism (18) is located above the false bottom (17). There are multiple flow stabilizers (19), which are evenly arranged around the center of the impeller stirring mechanism (18). The suction pipe (21) is located at the center of the impeller stirring mechanism (10). At the bottom of 8), the lower end of the foaming agent pipe (20) is connected to the suction pipe (21), the stator guide plate (22) is set at the bottom of the impeller stirring mechanism (18), the tailings pipe (16) is set at the bottom of the flotation cell (11), and the tailings pipe (16) is used to discharge the tailings after separation in the flotation cell (11), the foam scraper is set above the first foam zone (23) and the second foam zone (25), and the foam scraper is used to collect the clean coal flotated in the first foam zone (23) and the second foam zone (25) into the foam clean coal collection tank (14).

3. The wide-particle-size coal slime high-recovery flotation system according to claim 1, characterized in that: The wide-particle-size coal slime high recovery flotation system also includes a slurry mixing tank (30), the outlet of which is connected to the feed inlet (12) via a pipeline, and the slurry mixing tank (30) is used to stir and mix coal slime water and flotation reagents.

4. The wide-particle-size coal slime high-recovery flotation system according to claim 3, characterized in that: The wide-particle-size coal slime high recovery flotation system also includes a centrifugal dewatering machine (31), the inlet of which is connected to a foamed coal collection tank (14).

5. The wide-particle-size coal slime high-recovery flotation system according to claim 4, characterized in that: The wide-particle-size coal slime high recovery flotation system also includes a flotation column (32), the feed inlet of which is connected to the filtrate outlet of the centrifugal dewatering machine (31) and the fine particle overflow collection tank (13).

6. The wide-particle-size coal slime high-recovery flotation system according to claim 5, characterized in that: The wide-particle-size coal slime high-recovery flotation system also includes a diaphragm filter press (33), the feed inlet of which is connected to the concentrate outlet of the flotation column (32).

7. The wide-particle-size coal slime high-recovery flotation system according to claim 6, characterized in that: The wide-particle-size coal slime high-recovery flotation system also includes a thickener (34), the feed inlet of which is connected to the tailings outlet of the flotation column (32) and the tailings pipeline (16).

8. A flotation method for high recovery of wide-particle-size coal slime based on the wide-particle-size coal slime high-recovery flotation system as described in claim 7, characterized in that, Includes the following steps: Step 1: Slurry preparation. Coal slurry water is introduced into the slurry mixing tank (30) at a predetermined flow rate. Flotation reagents are added to the slurry mixing tank (30) in a predetermined ratio. The stirring mechanism in the slurry mixing tank (30) stirs and mixes the coal slurry water and flotation reagents at a preset speed to achieve selective flocculation and agglomeration of gangue particles in the slurry. Step 2: Separation by a first-stage flotation device. The slurry mixed in Step 1 is fed into the flotation device (10) through the feed port (12) and floated by the flotation device (10). The flotation in the flotation device (10) is a first-stage flotation. Step 3: Clean coal dewatering. The clean coal in the first flotation foam zone of Step 2 enters the centrifugal dewatering machine (31) for dewatering. The dewatered product is part of the final clean coal product. The centrifugal liquid and the clean coal in the overflow zone of the flotation device (10) are combined and enter the flotation column (32) for fine selection. Step 4: Second-stage flotation column cleaning. The second-stage flotation uses the centrifugal liquid generated by dewatering the concentrate in the overflow zone and the concentrate in the foam zone of the first-stage flotation device (10) as raw materials, and further removes gangue particles to ensure that the ash content of the final clean coal product is further reduced. Step 5: Second-stage clean coal dewatering. The clean coal product obtained from the second-stage flotation column enters the diaphragm filter press (33) for dewatering treatment and then passes through the final clean coal product to obtain all clean coal products. The diaphragm filter press (33) removes water and reuses it as circulating water. Step 6: Tailings dewatering. All the tailings from the second-stage flotation column and the first-stage flotation device (10) are fed into the thickener (34) for thickening to obtain all the tailings products. The bottom water of the thickener (34) is used as circulating water for reuse.

9. The flotation method for high recovery of wide-particle-size coal slime according to claim 8, characterized in that: The flotation reagents in step one include modifiers, dispersants, and flocculants.

10. The flotation method for high recovery of wide-particle-size coal slime according to claim 8, characterized in that: The specific steps of the separation process in step one of the flotation equipment include: The slurry processed in the slurry preparation tank (30) in step one is transported to the overflow zone (24) in the flotation cell (11) through the feed port (12) at a predetermined flow rate. Small coal particles directly become overflow under the action of water flow in the water surface flow layer and enter the fine particle overflow collection tank (13) to become the overflow zone concentrate. Small gangue particles in the slurry sink from the flow layer to the flotation zone under the action of flocculation and agglomeration to participate in the flotation process. Large coal particles and gangue particles in the slurry also sink from the flow layer together to participate in the subsequent flotation. The impeller stirring mechanism (18) rotates and generates negative pressure, drawing in air, collector and foaming agent from the air and foaming agent pipe (20), and cutting the air into appropriately sized bubbles. Finally, the bubbles rise through the false bottom (17) and the flow stabilizer (19) to the first foam zone (23) or the second foam zone (25). In the slurry-gas mixing zone, the slurry is drawn in through the suction pipe (21) and the stator guide plate (22) for mixing and circulation, so that the coarse coal particles are mineralized and collide with appropriately sized bubbles, attach and float to the flotation zone and the foam zone. Finally, the foam scraper scrapes the particles out to the foam fine coal collection tank (14) to become foam zone concentrate. The gangue particles are finally discharged into the tailings pipe (16) under the action of the flow field.

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