Efficient circulating turbulence microbubble flotation machine

Abstract

The invention discloses an efficient circulating turbulent flow microbubble flotation machine. Comprising an outer-layer barrel, an inner-layer barrel arranged in the outer-layer barrel, a rotating shaft arranged in the inner-layer barrel, a multi-layer coupling radial shearing impeller and a high-flux axial bidirectional conveying impeller which are sequentially arranged on the rotating shaft from top to bottom, and a lower flow guide separation barrel located under the high-flux axial bidirectional conveying impeller. According to the high-flux axial bidirectional conveying impeller, the recovery rate of clean coal can be effectively increased, and the overall separation effect of equipment is improved. Loss of flotation clean coal can be greatly reduced, and economic benefits of equipment production are improved; the concentrate distribution ring at the upper part of the outer-layer barrel body is annularly distributed, and clean coal foam is uniformly distributed and slowly flows and the volume of the foam is reduced when being conveyed to the foam groove at the outer end, so that the conveying process of clean coal is more stable, and the effect of reducing the loss of the clean coal is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of mineral separation and processing, and in particular to a high-efficiency circulating turbulent microbubble flotation machine. Background Art

[0002] With the increasing scarcity of global mineral resources and the deepening of green resource development policies, traditional mineral processing technology is facing unprecedented challenges. The rapid progress of coal mining technology has improved production efficiency, but it has also brought about the problem of increasingly fine mineral particle size. At the same time, the increase in high ash and intergrowth mineral content in the ore has greatly increased the difficulty of sorting and recycling fine-grained minerals. Especially in the treatment of fine-grained minerals, the effect of traditional flotation technology is not ideal. As the most economical and effective sorting method in the field of mineral processing, froth flotation technology has been widely used in mineral processing plants at home and abroad. The main equipment includes mechanical flotation machines and flotation columns. Although the mechanical agitator flotation machine has a long history, its sorting efficiency is obviously insufficient when processing fine particles with a diameter of less than 45 microns. Due to its low kinetic energy and small inertial force in the ore pulp, it is extremely difficult for bubbles and mineral particles to collide and complete recovery under the flow field conditions of conventional flotation machines.

[0003] As an efficient mineral sorting equipment, the flotation column has been highly valued in the field of mineral processing due to its simple structural design, flexible operation and controllability, and significant sorting efficiency. This type of equipment is particularly suitable for the sorting of low-grade, fine-grained and complex mineral resources. In recent years, a number of innovative achievements have emerged worldwide, such as the MTU filling medium flotation column developed by Michigan Technological University in the United States, the KFP series flotation column in Poland, and the cyclone-static microbubble flotation column developed by China University of Mining and Technology. These new flotation columns have shown sorting accuracy and efficiency that surpass traditional mechanical flotation machines in the treatment of fine-grained and difficult-to-select minerals. It is worth noting that there are still several technical bottlenecks in the actual industrial application of flotation columns. The core challenge is that it is difficult to maintain a high recovery rate while reducing the ash content of clean coal during the sorting process of high-interlinked minerals. At the same time, the shear shedding effect of coarse-grained mineral bubbles caused by the high turbulence intensity inside the equipment leads to a decrease in the sorting efficiency of coarse-grained materials, which makes it difficult to achieve ideal sorting effects in coarse-grained flotation.

[0004] In order to meet these challenges, the industry has an increasingly urgent need to develop new flotation equipment, with the goal of improving the recovery rate and sorting efficiency of fine-particle minerals while reducing energy consumption and environmental impact. Against this background, turbulent microbubble flotation equipment based on two-stage flotation came into being, specifically to solve the problems of low recovery rate and poor selectivity in the sorting of fine-particle coal slime. This technology not only optimizes the mineral sorting process and improves energy utilization efficiency, but also enhances the overall economy and sustainability of the flotation system, bringing innovation to the mineral processing industry. However, the existing two-stage flotation machine, as described in patent CN116422477A, ​​adopts the method of natural sinking and aggregation of tailings fine particles in the inner drum stirring zone, which is prone to insufficient collision between fine-particle minerals and bubbles, resulting in serious coarseness in the flotation tailings, and the flotation machine shaft extends from the upper motor to the lower side of the inner drum, making the shaft too long, which increases the energy consumption of the equipment and also makes it difficult to replace and repair the equipment normally. Therefore, it is urgent to further improve the existing technology and provide a more reliable flotation solution. Summary of the invention

[0005] In view of the above analysis, the embodiments of the present invention aim to provide a high-efficiency circulating turbulent microbubble flotation machine and a flotation method thereof, so as to solve the problems existing in the existing fine particle flotation equipment, such as low particle-bubble collision probability, poor selective recovery effect and long flotation process.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a high-efficiency circulating turbulent microbubble flotation machine, comprising: an outer cylinder, an inner cylinder arranged inside the outer cylinder, a rotating shaft arranged inside the inner cylinder, a multi-layer coupled radial shear impeller and a high-throughput axial bidirectional conveying impeller arranged on the rotating shaft in sequence from top to bottom, and a lower guide separation cylinder located directly below the high-throughput axial bidirectional conveying impeller;

[0007] The high-throughput axial bidirectional conveying impeller includes an inner impeller connected to the rotating shaft and an outer impeller connected to the outer periphery of the inner impeller. The inner impeller and the outer impeller are oriented in opposite directions, so that when the rotating shaft rotates, the inner impeller forms a downward thrust in the inner area of ​​the lower guide dividing cylinder, while the outer impeller forms an upward thrust in the outer area of ​​the lower guide dividing cylinder.

[0008] Preferably, the projection of the lower flow guide dividing tube in the horizontal plane is between the outer peripheral edge of the inner impeller and the inner peripheral edge of the outer impeller.

[0009] Preferably, the inner impeller is a left-handed impeller, and the outer impeller is a right-handed impeller. When in operation, when viewed from above, the rotating shaft is driven to rotate in a clockwise direction.

[0010] Alternatively, the inner impeller is a right-handed impeller, and the outer impeller is a left-handed impeller. When working, when viewed from a top view, the rotating shaft is driven to rotate counterclockwise.

[0011] Preferably, the high-throughput axial bidirectional conveying impeller further comprises a connecting sleeve fixedly sleeved on the rotating shaft, and the inner impeller comprises a plurality of inner impeller plates arranged in an annular shape and arranged on the connecting sleeve, and the inner impeller plates are arranged obliquely;

[0012] The outer impeller includes a plurality of connecting rods connected to the outer end of the inner impeller plate and an outer impeller plate connected to the end of the connecting rod. The outer impeller plate is U-shaped and includes a bottom plate connected to the end of the connecting rod and two flat plates perpendicular to the bottom plate and arranged at intervals. The two flat plates are parallel to each other and are both inclined. The inclination direction of the flat plates connected to the same connecting rod is opposite to the inclination direction of the inner impeller plate.

[0013] Preferably, a variable diameter cover is arranged inside the outer cylinder, the variable diameter cover comprises a cylindrical cover and a conical cover connected to the bottom of the cylindrical cover, the bottom of the conical cover is connected to the inner wall of the outer cylinder, the gap between the cylindrical cover and the outer cylinder forms a concentrate collecting tank, and a concentrate pipe connected to the concentrate collecting tank is arranged on the outer wall of the outer cylinder;

[0014] An annular concentrate distribution trough is arranged on the inner periphery of the variable diameter cover, and the concentrate distribution trough is connected to the concentrate collecting trough through a plurality of annular concentrate conveying troughs evenly spaced apart.

[0015] Preferably, the inner cylinder comprises an upper cylinder section, an intermediate cylinder section and a lower cylinder section from top to bottom, the lower part of the upper cylinder section has an inverted cone-shaped cylinder section, and the lower end of the inverted cone-shaped cylinder section extends into the intermediate cylinder section;

[0016] The middle cylinder section is spherical, and a plurality of anti-rotation grooves are evenly spaced along the circumferential direction on the wall surface of the middle cylinder section, and the anti-rotation grooves are inclined;

[0017] The lower cylinder section is cylindrical, and a gap between the bottom of the lower cylinder section and the bottom inner wall of the outer cylinder forms a tailings diversion port. The lower diversion dividing cylinder is connected to the inner wall of the lower cylinder section through a mounting bracket.

[0018] Preferably, a bowl-shaped middling ore collecting trough is provided at the bottom of the outer cylinder, a tailings collecting trough is formed by a gap between the outer peripheral edge of the bowl-shaped middling ore collecting trough and the inner wall of the side of the outer cylinder, and a tailings pipe connected to the tailings collecting trough is provided on the outer wall of the outer cylinder;

[0019] A plurality of circularly arranged arc baffles are provided in the bowl-shaped middling ore collecting trough, the inner ends of the arc baffles are connected to the lower cylinder section, the outer ends of the arc baffles are cooperatively connected to the inner side walls of the bowl-shaped middling ore collecting trough, and a tailings diversion channel connected to the tailings diversion port is formed between adjacent arc baffles;

[0020] A conical guide block is provided at the bottom of the outer cylinder and is located on the inner periphery of the lower cylinder section. A gap is left between the conical guide block and the inner end of the arc-shaped baffle plate. The upper surface of the conical guide block is recessed downward to form a guide groove located directly below the lower guide dividing cylinder.

[0021] Preferably, an upper isolating cylinder is arranged inside the outer cylinder, the multi-layer coupled radial shear impeller is arranged inside the upper isolating cylinder, and the high-throughput axial bidirectional conveying impeller is located in the space between the upper isolating cylinder and the lower guide dividing cylinder.

[0022] Preferably, the high-efficiency circulation turbulent microbubble flotation machine further comprises a feed assembly and a motor drivingly connected to the upper end of the rotating shaft, wherein the feed assembly comprises a main feed pipe, an annular distribution pipe connected to the main feed pipe and arranged on the outer periphery of the inner cylinder, and a plurality of distribution pipes connected to the annular distribution pipe, wherein the ends of the distribution pipes are connected to the side wall of the upper isolation cylinder along the circumferential tangent direction;

[0023] The interior of the rotating shaft is hollow to form an air intake passage, and an air intake hole is opened at the bottom of the rotating shaft. The bottom of the rotating shaft extends into the lower flow guide separation cylinder.

[0024] Preferably, the multi-layer coupled radial shear impeller comprises at least two radial shear impellers spaced apart in a vertical direction, and the radial shear impeller comprises a plurality of rotor impeller plates connected to the rotating shaft in an annular shape;

[0025] The inner wall of the upper isolating cylinder is provided with at least two stator plate units, the number of which is the same as that of the radial shear impellers, and the at least two stator plate units are arranged at intervals in the vertical direction, and the stator plate unit includes a plurality of stator plates connected to the inner wall of the upper isolating cylinder in an annular shape;

[0026] The radial shear impeller and the stator plate unit are staggered in the vertical direction, and the space between two adjacent stator plates in the vertical direction allows the rotor impeller plate to pass smoothly during rotation;

[0027] The rotor impeller plate and the stator plate are both trapezoidal plates provided with vertical grid holes.

[0028] The present invention also provides a high-efficiency circulating turbulent microbubble flotation method, and adopts the high-efficiency circulating turbulent microbubble flotation device to carry out enhanced flotation of minerals.

[0029] The beneficial effects of the present invention are:

[0030] (1) The present invention provides a high-efficiency circulation turbulent microbubble flotation machine, in which a special conveying impeller structure is designed: a high-throughput axial bidirectional conveying impeller, which can effectively improve the recovery rate of clean coal and improve the overall sorting effect of the equipment; the high-throughput axial bidirectional conveying impeller includes an inner impeller for internal downward conveying and an outer impeller for external upward conveying, and the inner and outer impellers are oriented in opposite directions, which promotes the downward sorting of tail coal while conveying the middle ore to the upper part through the outer impeller and flowing into the stirring zone of the multi-layer coupled radial shear impeller, thereby forming a local internal circulation of the middle ore in the inner cylinder area, forming a multiple scavenging effect on the middle ore, thereby greatly ensuring the yield of the clean coal product.

[0031] (2) The present invention can significantly reduce the loss of clean coal during flotation and improve the economic benefits of equipment production; the concentrate distribution ring on the upper part of the outer cylinder of the present invention is distributed in a ring shape, and the clean coal foam is evenly distributed and has a slow flow rate when being transported to the outer end foam tank, and the bubble volume becomes smaller, making the clean coal transportation process more stable, thereby achieving the effect of reducing the loss of clean coal.

[0032] (3) The motor shaft of the present invention is shorter, which avoids the problem of excessive energy consumption caused by the shaft running through the entire machine in the traditional two-stage flotation machine. At the same time, it is conducive to the replacement and maintenance of equipment parts, effectively reducing the operating cost of the equipment and improving the economic benefits of the equipment in sorting minerals.

[0033] (4) In the present invention, the feeding of the annular distribution pipe in the feeding assembly can ensure the uniform distribution of the input slurry and the stability during transportation. The swirl feeding can be formed through the distribution pipe, and the slurry and the multi-layer coupled radial shear impeller can produce more intense collision and shearing effects, which can produce more abundant microbubbles, increase the collision probability of fine particles and microbubbles, and improve the mineralization efficiency.

[0034] (5) The air inlet channel is located inside the motor shaft, which is conducive to the suction and shearing of air to form microbubbles and the scrubbing of slurry particles by the multi-layer coupled radial shear impeller, thereby fully improving the bubble mineralization efficiency.

[0035] (6) The bowl-shaped tailings collection tank is provided with a number of baffles arranged in a circle to provide upward flow for the sinking tailings, promote their overflow to the tailings collection tank, reduce the turbulence intensity of the tailings slurry in a short time, increase the energy dissipation of the tailings, effectively reduce the deposition of tailings at the bottom of the outer cylinder, and improve the overall flotation efficiency of the equipment. In conjunction with the conical guide block set in the bowl-shaped tailings collection tank, the slurry falling in the lower guide separation cylinder can flow evenly and scatter, providing upward momentum and a certain horizontal flow for the middle-ore coal slime particles with mineralized bubbles attached therein, so that they are scattered into the outer periphery of the lower guide separation cylinder, and in conjunction with the lifting force generated by the outer impeller on the outer periphery of the lower guide separation cylinder, these middle-ore coal slime particles can be transported upward to the upper cylinder section again for recycling and re-sorting, thereby improving the recovery rate of flotation products.

[0036] (7) The turbulent microbubble flotation machine of the present invention can be used in combination by using a stepped arrangement or a stacked arrangement. The stepped arrangement allows the equipment to perform multiple sweeps on the tailing coal, which is beneficial to improving the recovery rate of the flotation product; the stacked arrangement can greatly reduce the footprint of the equipment, improve space utilization, and reduce labor maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic cross-sectional structure diagram of a turbulent microbubble flotation machine with high efficiency circulation in Example 1;

[0038] Figure 2 It is a schematic diagram of the external structure of the turbulent microbubble flotation machine with high efficiency circulation in Example 1;

[0039] Figure 3 It is a schematic diagram of the internal structure of the turbulent microbubble flotation machine with high efficiency circulation in Example 1;

[0040] Figure 4 A schematic diagram of the internal structure of the turbulent microbubble flotation machine with high efficiency circulation in Example 1 from another perspective;

[0041] Figure 5 It is a schematic diagram of the structure of the multi-layer coupled radial shear impeller and the high-throughput axial bidirectional conveying impeller of Example 1 being installed in cooperation with the rotating shaft;

[0042] Figure 6 It is a structural schematic diagram of a high-throughput axial bidirectional conveying impeller of Example 1;

[0043] Figure 7 This is a schematic diagram of the structure of the feed assembly of Example 1 being arranged on the inner cylinder;

[0044] Figure 8 This is a schematic diagram of the internal structure of the inner cylinder of Example 1;

[0045] Fig. 9It is a schematic diagram of the structure of the material distribution pipe and the upper isolation cylinder in the top view of the embodiment 1;

[0046] Fig.10 The test results of the yield and ash content of clean coal and tail coal of the three flotation equipments TFM, MFC and XFD in the test example are shown;

[0047] Fig.11 The flotation recovery index test results of the three flotation equipments TFM, MFC and XFD in the test case;

[0048] Fig.12 It is a schematic diagram of a plurality of turbulent microbubble flotation machine devices in Example 2 arranged in a stepped manner;

[0049] Fig.13 This is a schematic diagram of a plurality of turbulent microbubble flotation machine devices in Example 2 arranged in a stacked manner.

[0050] Description of reference numerals:

[0051] 1—outer cylinder; 11—variable cover; 12—concentrate collecting trough; 13—concentrate pipe; 14—concentrate distribution trough; 15—concentrate conveying trough; 16—bowl-shaped middling ore collecting trough; 17—tailings pipe; 18—conical guide block; 19—upper isolation cylinder; 111—columnar cover; 112—conical cover; 161—tailings collecting trough; 162—arc baffle; 163—tailings guide channel; 181—guide groove; 191—stator plate unit; 192—stator plate;

[0052] 2—inner cylinder; 21—upper cylinder section; 22—middle cylinder section; 23—lower cylinder section; 211—inverted cone-shaped cylinder section; 221—rotation-stopping groove; 24—tailings diversion port;

[0053] 31—motor; 32—rotating shaft; 321—air inlet passage; 322—air inlet hole;

[0054] 4—multi-layer coupled radial shear impeller; 41—radial shear impeller; 411—rotor impeller plate;

[0055] 5—high-throughput axial bidirectional conveying impeller; 51—inner impeller; 52—outer impeller; 53—connecting sleeve; 511—inner impeller plate; 521—connecting rod; 522—outer impeller plate; 5221—bottom plate; 5222—flat plate;

[0056] 6—lower guide separation tube; 61—mounting bracket;

[0057] 7—feeding assembly; 71—feeding pipe; 72—annular distribution pipe; 73—distribution pipe. DETAILED DESCRIPTION

[0058] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0059] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0060] Example 1

[0061] A high-efficiency circulating turbulent microbubble flotation machine, comprising: an outer cylinder 1, an inner cylinder 2 arranged inside the outer cylinder 1, a rotating shaft 32 arranged inside the inner cylinder 2, a multi-layer coupled radial shear impeller 414 and a high-throughput axial bidirectional conveying impeller 5 arranged on the rotating shaft 32 in sequence from top to bottom, a lower guide separation cylinder 6 located directly below the high-throughput axial bidirectional conveying impeller 5, a feed assembly 7, and a motor 31 drivingly connected to the upper end of the rotating shaft 32;

[0062] The high-throughput axial bidirectional conveying impeller 5 includes an inner impeller 51 connected to the rotating shaft 32 and an outer impeller 52 connected to the outer periphery of the inner impeller 51. The inner impeller 51 and the outer impeller 52 are oriented in opposite directions, so that when the rotating shaft 32 rotates, the inner impeller 51 forms a downward thrust in the internal area of ​​the lower guide dividing tube 6, while the outer impeller 52 forms an upward thrust in the external area of ​​the lower guide dividing tube 6.

[0063] The projection of the lower flow guide separation cylinder 6 in the horizontal plane is between the outer peripheral edge of the inner impeller 51 and the inner peripheral edge of the outer impeller 52. In other words, the lower flow guide separation cylinder 6 is coaxially arranged with the rotating shaft 32, and the inner diameter of the lower flow guide separation cylinder 6 is between the diameter of the inner impeller 51 and the diameter of the outer impeller 52.

[0064] The inner impeller 51 is a left-handed impeller, and the outer impeller 52 is a right-handed impeller. When working, when viewed from a top view, the rotating shaft 32 is driven to rotate in a clockwise direction.

[0065] Alternatively, the inner impeller 51 is a right-handed impeller, and the outer impeller 52 is a left-handed impeller. During operation, the rotating shaft 32 is driven to rotate in a counterclockwise direction when viewed from a top view.

[0066] Reference Figure 6In this embodiment, the inner impeller 51 is a left-handed impeller, and the outer impeller 52 is a right-handed impeller. When working, the motor 31 drives the rotating shaft 32 to rotate clockwise (from a top view). During the rotation, the inner impeller 51 generates a downward thrust on the slurry below it (mainly the slurry located in the lower flow guide separation cylinder 6); while the outer impeller 52 generates an upward lifting force on the slurry below it (mainly the slurry located outside the lower flow guide separation cylinder 6). Thus, fluid driving forces in different directions are generated inside and outside the lower flow guide separation cylinder 6, forming a re-sorting effect in a local area.

[0067] In this embodiment, the high-throughput axial bidirectional conveying impeller 5 further includes a connecting sleeve 53 fixedly sleeved on the rotating shaft 32, and the inner impeller 51 includes a plurality of inner impeller plates 511 arranged in an annular shape and arranged on the connecting sleeve 53. The inner impeller plates 511 are arranged obliquely (with Figure 6 Take the inner impeller plate 511 shown in A as an example, the left side is higher and the right side is lower);

[0068] The outer impeller 52 includes a plurality of connecting rods 521 connected to the outer end of the inner impeller plate 511 and an outer impeller plate 522 connected to the end of the connecting rod 521. The outer impeller plate 522 is U-shaped and includes a bottom plate 5221 connected to the end of the connecting rod 521 and two flat plates 5222 perpendicular to the bottom plate 5221 and spaced apart. The two flat plates 5222 are parallel to each other and are both inclined (with Figure 6 Taking the flat plate 5222 shown in FIG. 5B as an example, the left side is lower and the right side is higher), the inclination direction of the flat plate 5222 connected to the same connecting rod 521 is opposite to the inclination direction of the inner impeller plate 511.

[0069] When the motor 31 drives the rotating shaft 32 to rotate clockwise, the inner impeller 51 arranged in a left-handed manner mainly provides downward thrust for the fine-grained tailings; in the U-shaped outer impeller 52, the right-handed flat plate 5222 mainly provides upward lifting thrust for the coarse-grained concentrate. At the same time, the U-shaped impeller of the outer impeller 52 is conducive to cutting the air dispersed from the air inlet 322 to form microbubbles, thereby increasing the collision probability between the coal slime particles and the bubbles in the slurry. The inside of the U-shaped cavity can provide sufficient radial driving force for the slurry, thereby ensuring that there is sufficient power to allow the concentrate entering the middle cylinder section 22 to be thrown out of the inner cylinder 2 from the anti-rotation groove 221.

[0070] In this embodiment, a variable diameter cover 11 is arranged inside the outer cylinder 1, and the variable diameter cover 11 includes a cylindrical cover 111 and a conical cover 112 connected to the bottom of the cylindrical cover 111, and the bottom of the conical cover 112 is connected to the inner wall of the outer cylinder 1, and the gap between the cylindrical cover 111 and the outer cylinder 1 forms a concentrate collecting tank 12, and a concentrate pipe 13 connected to the concentrate collecting tank 12 is arranged on the outer wall of the outer cylinder 1;

[0071] An annular concentrate distribution trough 14 is provided on the inner periphery of the variable diameter cover 11 , and the concentrate distribution trough 14 is connected to the concentrate collecting trough 12 through a plurality of annular concentrate conveying troughs 15 evenly spaced apart.

[0072] In this embodiment, the inner cylinder 2 includes an upper cylinder section 21, an intermediate cylinder section 22 and a lower cylinder section 23 from top to bottom. The lower part of the upper cylinder section 21 has an inverted cone-shaped cylinder section 211, and the lower end of the inverted cone-shaped cylinder section 211 extends into the intermediate cylinder section 22.

[0073] The middle cylinder section 22 is spherical, and a plurality of anti-rotation grooves 221 are evenly spaced along the circumferential direction on the wall surface of the middle cylinder section 22, and the anti-rotation grooves 221 are inclined. After the swirling slurry in the middle cylinder section 22 is thrown out through the anti-rotation grooves 221, it can flow out more evenly to the surroundings by virtue of the spherical middle cylinder section 22.

[0074] The lower cylinder section 23 is cylindrical, and the gap between the bottom of the lower cylinder section 23 and the bottom inner wall of the outer cylinder 1 forms a tailings diversion port 24 . The lower diversion dividing cylinder 6 is connected to the inner wall of the lower cylinder section 23 via a mounting bracket 61 .

[0075] In this embodiment, a bowl-shaped middling ore collecting trough 16 is provided at the bottom of the outer cylinder 1, and a gap between the outer peripheral edge of the bowl-shaped middling ore collecting trough 16 and the inner wall of the side of the outer cylinder 1 forms a tailings collecting trough 161, and a tailings pipe 17 connected to the tailings collecting trough 161 is provided on the outer wall of the outer cylinder 1;

[0076] A plurality of circularly arranged arc baffles 162 are provided in the bowl-shaped middling ore collecting trough 16. The inner ends of the arc baffles 162 are connected to the lower cylinder section 23. The outer ends of the arc baffles 162 are matched and connected to the inner side wall of the bowl-shaped middling ore collecting trough 16. A tailings diversion channel 163 connected to the tailings diversion port 24 is formed between adjacent arc baffles 162.

[0077] A conical guide block 18 is provided at the bottom of the outer cylinder 1 and is located on the inner periphery of the lower cylinder section 23. A gap is left between the conical guide block 18 and the inner end of the arc-shaped baffle plate 162. The upper surface of the conical guide block 18 is recessed downward to form a guide groove 181 located directly below the lower guide dividing cylinder 6.

[0078] In this embodiment, an upper isolation cylinder 19 is arranged inside the outer cylinder 1, a multi-layer coupled radial shear impeller 414 is arranged inside the upper isolation cylinder 19, and a high-throughput axial bidirectional conveying impeller 5 is located in the space between the upper isolation cylinder 19 and the lower guide separation cylinder 6.

[0079] In this embodiment, the feed assembly 7 includes a main feed pipe 71, an annular distribution pipe 72 connected to the main feed pipe 71 and arranged on the outer periphery of the inner cylinder 2, and a plurality of distribution pipes 73 connected to the annular distribution pipe 72, and the ends of the distribution pipes 73 are connected to the side wall of the upper isolation cylinder 19 along the circumferential tangent direction; so that the slurry output by the distribution pipes 73 will generate a vortex in the upper isolation cylinder 19, and the vortex direction generated by each distribution pipe 73 is the same.

[0080] In this embodiment, two distribution pipes 73 are included, and the swirl direction generated by the slurry output by the two distribution pipes 73 is clockwise, which is the same as the rotation direction of the shaft 32; the swirl feed can cooperate with the multi-layer coupled radial shear impeller 414, so that the slurry and the multi-layer coupled radial shear impeller 414 produce more violent collision and shearing effects.

[0081] The interior of the rotating shaft 32 is hollow to form an air inlet passage 321 , and an air inlet hole 322 is opened at the bottom of the rotating shaft 32 . The bottom of the rotating shaft 32 extends into the lower guide separation cylinder 6 .

[0082] In this embodiment, the multi-layer coupled radial shear impeller 414 includes at least two radial shear impellers 41 spaced apart in the vertical direction, and the radial shear impeller 41 includes a plurality of rotor impeller plates 411 connected to the rotating shaft 32 in an annular shape;

[0083] At least two stator plate 192 units 191, the same number as the radial shear impeller 41, are arranged on the inner wall of the upper isolating cylinder 19. The at least two stator plate 192 units 191 are arranged at intervals in the vertical direction. The stator plate 192 units 191 include a plurality of stator plates 192 connected to the inner wall of the upper isolating cylinder 19 in a ring shape. In this embodiment, there are two stator plate 192 units 191 and two rotor impeller plates 411.

[0084] The radial shear impeller 41 and the stator plate 192 unit 191 are staggered in the vertical direction, and the space between two adjacent stator plates 192 in the vertical direction allows the rotor impeller plate 411 to pass smoothly during rotation; the radial shear impeller 41 and the stator plate 192 are both trapezoidal plates with vertical grid holes. When the radial shear impeller 41 rotates relative to the stator plate 192 unit 191, the rotor impeller plate 411 and the stator plate 192 cooperate to produce a violent radial shearing effect, so that the bubbles can be cut to form a large number of microbubbles. The increase in microbubbles can increase the collision frequency between fine particles and bubbles in the slurry, thereby significantly improving the mineralization effect.

[0085] It should be noted that, in this embodiment, the flotation object is fine-grained minerals with a diameter less than 20 μm.

[0086] The main working process and principle of the turbulent microbubble flotation machine of this embodiment are described below:

[0087] (1) The slurry after slurry adjustment is fed into the feed pipe 71, and is evenly distributed to the distribution pipe 73 through the annular distribution pipe 72, and then enters the upper isolation cylinder 19 along the tangential direction through the distribution pipe 73, and generates a swirling flow in the upper isolation cylinder 19;

[0088] (2) At the same time, the inner impeller 51 of the high-throughput axial bidirectional conveying impeller 5 is driven by the rotating shaft 32 to rotate clockwise, and a negative pressure is formed near the air inlet 322 at the bottom of the rotating shaft 32 at the lower part of the inner impeller 51, so that the air in the external environment is sucked in through the upper end of the rotating shaft 32, and enters the inner cylinder 2 through the air inlet channel 321, and is evenly dispersed. After the bubbles float up and enter the upper isolation cylinder 19, they are efficiently cut by the multi-layer coupled radial shear impeller 414 to form a large number of microbubbles, and meet the downward-moving swirling feed slurry. Under the multiple effects of the swirling action and the stirring and shearing action of the multi-layer coupled radial shear impeller 414, the coal slime particles in the slurry fully collide with the microbubbles, thereby achieving efficient mineralization.

[0089] (3) When the inner impeller 51 of the high-throughput axial bidirectional conveying impeller 5 rotates clockwise, a downward thrust is generated in the lower guide separation cylinder 6 below it. After the slurry is mineralized with the rising microbubbles in the upper separation cylinder 19, the fine tail coal particles with higher density are transported downward by the downward thrust generated by the inner impeller 51, meet the rising microbubbles at the lower air inlet 322, and form a countercurrent circulation again, further increasing the collision probability between fine particles and bubbles and reducing the coarse particle phenomenon in the fine particle separation;

[0090] (4) Fine tailings and some of the medium-sized coal slime particles flow downward into the bowl-shaped medium-sized coal collecting tank 16, and flow evenly and scatteredly toward the outer periphery of the cone-shaped guide block 18 through the guide groove 181 on the cone-shaped guide block 18. The fine tailings that are not attached to the mineralized bubbles continue to fall and enter the tailings guide channel 163 through the tailings guide port 24, and finally overflow to the tailings collecting tank 161 for collection, and then are discharged through the tailings pipe 17; some of the medium-sized coal slime particles that are attached to the mineralized bubbles flow to the outside of the lower guide separation cylinder 6, and are transported upward again under the upward lifting thrust generated by the outer impeller 52 of the high-throughput axial bidirectional conveying impeller 5, and are recycled and re-sorted, thereby improving the flotation product recovery rate;

[0091] (5) The outer impeller 52 of the high-throughput axial bidirectional conveying impeller 5 generates an upward lifting force in the area between the outer side of the lower guide and separation cylinder 6 and the inner cylinder 2, and conveys the particles adhering to the mineralized bubbles in the lower cylinder section 23 upward. After entering the middle cylinder section 22, the particles are knocked out from the anti-rotation groove 221 and pushed upward to the concentrate distribution trough 14. The annular structure of the concentrate distribution trough 14 is conducive to accelerating the conveying speed of the clean coal, reducing the probability of desorption of mineral particles and bubbles, and ensuring a steady flow during the conveying of the clean coal; the finely controlled foam in the concentrate distribution trough 14 is then collected to the concentrate collection trough 12 through the concentrate conveying trough 15, and finally flows out from the concentrate pipe 13.

[0092] (6) Furthermore, the baffle in the bowl-shaped middling ore collecting trough 16 gathers the sinking middling ore to the bottom of the lower cylinder section 23. Under the upward thrust of the outer impeller 52 of the high-throughput axial bidirectional conveying impeller 5, the middling ore slime particles are conveyed upward to the upper part of the multi-layer coupled radial shear impeller 414 through the channel between the outer side of the lower guide and separation cylinder 6 and the lower cylinder section 23, thereby forming a recycling re-sorting of the middling ore slime, thereby improving the flotation product recovery rate and the overall flotation efficiency of the equipment.

[0093] Compared with the prior art, the high-efficiency circulation turbulent microbubble flotation machine provided in this embodiment adopts an inner and outer nested double-layer cylinder, and the inner cylinder 2 is completely located in the outer cylinder 1. Compared with the flotation column, it is lower in height and occupies less space; the motor 31 shaft 32 is shorter in length, avoiding the excessive energy consumption of the traditional flotation machine caused by the shaft 32 running through the entire machine. On the one hand, it significantly reduces the energy consumption of the equipment operation, and on the other hand, it shortens the flotation process of the equipment and improves the flotation efficiency; with the help of the inner and outer reverse impellers of the radial conveying impeller, the tailings are conveyed downward and the middlings are circulated upward at the same time. Under the flotation process of high turbulence middling circulation in a small space, the flotation mineral recovery rate can be effectively improved, and the overall flotation efficiency of the equipment can be improved.

[0094] Test Case

[0095] In order to further illustrate the present invention, the following flotation experiment is carried out using the high-efficiency circulating turbulent microbubble flotation machine (with a volume of 3L, denoted as TFM) of Example 1, and a conventional laboratory flotation machine (XFD-3L, denoted as XFD) and an ultrafine turbulent flotation machine (denoted as MFC) with the same structure as Example 1 of CN116422477A (the applicant's previous patent) are used as comparisons. The same flotation process parameters are adopted and the raw coal of Daizhuang Coal Preparation Plant is used as the flotation feed for the experiment.

[0096] The flotation process parameters are as follows: the collector and frother are original diesel and octanol, respectively, with dosages of 500g / t and 100g / t, respectively; the flotation feed concentration is maintained at 100g / L, and the flotation time is 3min.

[0097] The particle size composition of flotation feed is shown in Table 1:

[0098] Table 1 Flotation feed particle size composition

[0099]

[0100]

[0101] Particle size composition analysis: -0.038mm material accounts for 55.62% of the total sample yield, with an ash content of 44.02%. The fine particle content is high, and fine mud cover and entrainment are prone to occur, which is not conducive to conventional flotation separation. The slime content and ash content of each particle size are unevenly distributed, and the ash content of the slime increases with the decrease of particle size. The +0.212mm particle size has a small amount of slime, with an ash content of 5.53%, but this part of low-ash slime is easy to desorb during the flotation separation process, and runs coarsely to the flotation tail coal product, which cannot be effectively recovered, resulting in low tail coal ash content.

[0102] The yield and ash content of clean coal and tail coal of three flotation equipments TFM, MFC and XFD are as follows Fig.10 As shown in the figure, TFM clean coal and TFM tail respectively represent the clean coal and tail coal obtained by TFM flotation, MFC clean coal and MFC tail respectively represent the clean coal and tail coal obtained by MFC flotation, XFD clean coal and XFD tail respectively represent the clean coal and tail coal obtained by XFD flotation. The flotation recovery index results of the three flotation equipment are shown in Fig.11 shown.

[0103] From the flotation results, it can be seen that TFM has the best effect and the highest tailing ash content, and the flotation kinetics of TFM is faster, which is conducive to reducing the size of the equipment.

[0104] XFD: Conventional laboratory flotation machine (XFD-3L); the clean coal yield is lower than TFM, while the tailing coal ash content is the lowest, and the mineral separation performance is significantly lower than TFM;

[0105] MFC: Example 1 of the patent (CN116422477A), the flotation kinetics of TFM is significantly faster than that of MFC. In comparison, TFM has a higher separation efficiency.

[0106] Example 2

[0107] The high-efficiency circulating turbulent microbubble flotation machine of the present invention can be used in combination of multiple devices. This embodiment illustrates two arrangements: step arrangement and stacking arrangement.

[0108] 1. Fig.12 The diagram shows the stepped arrangement of multiple turbulent microbubble flotation equipment:

[0109] The flotation equipment is arranged in an oblique step manner, the lower end of the tailing pipe 17 of the upper flotation equipment is horizontally aligned with the upper end of the feed pipe 71 of the lower flotation equipment, and the two ports are connected by a flange pipe. After the slurry of the upper flotation equipment completes the primary mineralization sorting, it flows out from the tailing pipe 17 of the upper flotation equipment and flows into the feed pipe 71 of the lower flotation equipment, and completes the secondary mineralization sorting in the lower flotation equipment. This step arrangement is conducive to multiple scavenging of the tailings in the flotation product, improving the flotation mineral recovery rate and improving the overall sorting effect of the equipment.

[0110] 2. Fig.13 The stacking arrangement of multiple turbulent microbubble flotation equipment is shown in the figure:

[0111] The flotation equipment is stacked vertically, the feed pipe 71 and tailing pipe 17 of the upper and lower flotation equipment are aligned in the vertical direction, the tailing pipe 17 of the upper flotation equipment is connected to the feed pipe 71 of the lower flotation equipment, and they are arranged in sequence in this way. This stacking arrangement is conducive to reducing the floor space occupied by multiple flotation equipment, while improving the space utilization of the equipment, reducing the labor cost of maintaining multiple equipment, reducing the difficulty of construction layout, and further improving the production profit of the equipment.

[0112] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0113] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A high-efficiency circulating turbulent microbubble flotation machine, characterized in that: include: An outer cylinder, an inner cylinder arranged inside the outer cylinder, a rotating shaft arranged inside the inner cylinder, a multi-layer coupled radial shear impeller and a high-throughput axial bidirectional conveying impeller arranged on the rotating shaft in sequence from top to bottom, and a lower guide separation cylinder located directly below the high-throughput axial bidirectional conveying impeller; The high-throughput axial bidirectional conveying impeller includes an inner impeller connected to the rotating shaft and an outer impeller connected to the outer periphery of the inner impeller. The inner impeller and the outer impeller are oriented in opposite directions, so that when the rotating shaft rotates, the inner impeller forms a downward thrust in the inner area of ​​the lower guide dividing cylinder, while the outer impeller forms an upward thrust in the outer area of ​​the lower guide dividing cylinder.

2. The high-efficiency circulating turbulent microbubble flotation machine according to claim 1, characterized in that: The projection of the lower flow guide dividing cylinder in the horizontal plane is between the outer peripheral edge of the inner impeller and the inner peripheral edge of the outer impeller.

3. The high-efficiency circulating turbulent microbubble flotation machine according to claim 2, characterized in that: The inner impeller is a left-handed impeller, and the outer impeller is a right-handed impeller. When in operation, when viewed from above, the rotating shaft is driven to rotate in a clockwise direction; Alternatively, the inner impeller is a right-handed impeller, and the outer impeller is a left-handed impeller. When working, when viewed from a top view, the rotating shaft is driven to rotate counterclockwise.

4. The high-efficiency circulating turbulent microbubble flotation machine according to claim 3, characterized in that: The high-throughput axial bidirectional conveying impeller further comprises a connecting sleeve fixedly sleeved on the rotating shaft, the inner impeller comprises a plurality of inner impeller plates arranged in an annular shape and arranged on the connecting sleeve, and the inner impeller plates are arranged obliquely; The outer impeller includes a plurality of connecting rods connected to the outer end of the inner impeller plate and an outer impeller plate connected to the end of the connecting rod. The outer impeller plate is U-shaped and includes a bottom plate connected to the end of the connecting rod and two flat plates perpendicular to the bottom plate and arranged at intervals. The two flat plates are parallel to each other and are both inclined. The inclination direction of the flat plates connected to the same connecting rod is opposite to the inclination direction of the inner impeller plate.

5. The high-efficiency circulating turbulent microbubble flotation machine according to claim 4, characterized in that: A variable diameter cover is arranged inside the outer cylinder, and the variable diameter cover includes a cylindrical cover and a conical cover connected to the bottom of the cylindrical cover, the bottom of the conical cover is connected to the inner wall of the outer cylinder, and the gap between the cylindrical cover and the outer cylinder forms a concentrate collecting tank, and a concentrate pipe connected to the concentrate collecting tank is arranged on the outer wall of the outer cylinder; An annular concentrate distribution trough is arranged on the inner periphery of the variable diameter cover, and the concentrate distribution trough is connected to the concentrate collecting trough through a plurality of annular concentrate conveying troughs evenly spaced apart.

6. The high-efficiency circulating turbulent microbubble flotation machine according to claim 5, characterized in that: The inner cylinder body includes an upper cylinder body section, a middle cylinder body section and a lower cylinder body section from top to bottom, the lower part of the upper cylinder body section has an inverted cone-shaped cylinder body portion, and the lower end of the inverted cone-shaped cylinder body portion extends into the middle cylinder body section; The middle cylinder section is spherical, and a plurality of anti-rotation grooves are evenly spaced along the circumferential direction on the wall surface of the middle cylinder section, and the anti-rotation grooves are inclined; The lower cylinder section is cylindrical, and a gap between the bottom of the lower cylinder section and the bottom inner wall of the outer cylinder forms a tailings diversion port. The lower diversion dividing cylinder is connected to the inner wall of the lower cylinder section through a mounting bracket.

7. The high-efficiency circulating turbulent microbubble flotation machine according to claim 6, characterized in that: A bowl-shaped middling ore collecting trough is provided at the bottom of the outer cylinder, a gap between the outer peripheral edge of the bowl-shaped middling ore collecting trough and the inner wall of the side of the outer cylinder forms a tailings collecting trough, and a tailings pipe connected to the tailings collecting trough is provided on the outer wall of the outer cylinder; A plurality of circularly arranged arc baffles are provided in the bowl-shaped middling ore collecting trough, the inner ends of the arc baffles are connected to the lower cylinder section, the outer ends of the arc baffles are cooperatively connected to the inner side walls of the bowl-shaped middling ore collecting trough, and a tailings diversion channel connected to the tailings diversion port is formed between adjacent arc baffles; A conical guide block is provided at the bottom of the outer cylinder and is located on the inner periphery of the lower cylinder section. A gap is left between the conical guide block and the inner end of the arc-shaped baffle plate. The upper surface of the conical guide block is recessed downward to form a guide groove located directly below the lower guide dividing cylinder.

8. The high-efficiency circulating turbulent microbubble flotation machine according to claim 7, characterized in that: An upper isolating cylinder is arranged inside the outer cylinder, the multi-layer coupled radial shear impeller is arranged inside the upper isolating cylinder, and the high-throughput axial bidirectional conveying impeller is located in the space between the upper isolating cylinder and the lower guide dividing cylinder.

9. The high-efficiency circulating turbulent microbubble flotation machine according to claim 8, characterized in that: It also includes a feed assembly and a motor drivingly connected to the upper end of the rotating shaft, the feed assembly includes a main feed pipe, an annular distribution pipe connected to the main feed pipe and arranged on the outer periphery of the inner cylinder, and a plurality of distribution pipes connected to the annular distribution pipe, the ends of the distribution pipes are connected to the side wall of the upper isolation cylinder along the circumferential tangent direction; The interior of the rotating shaft is hollow to form an air inlet passage, the bottom of the rotating shaft is provided with an air inlet hole, and the bottom of the rotating shaft extends into the lower flow guide separation cylinder.

10. The high-efficiency circulating turbulent microbubble flotation machine according to claim 8, characterized in that: The multi-layer coupled radial shear impeller comprises at least two radial shear impellers spaced apart in a vertical direction, and the radial shear impeller comprises a plurality of rotor impeller plates connected to the rotating shaft in an annular shape; The inner wall of the upper isolating cylinder is provided with at least two stator plate units, the number of which is the same as that of the radial shear impellers, and the at least two stator plate units are arranged at intervals in the vertical direction, and the stator plate unit includes a plurality of stator plates connected to the inner wall of the upper isolating cylinder in an annular shape; The radial shear impeller and the stator plate unit are staggered in the vertical direction, and the space between two adjacent stator plates in the vertical direction allows the rotor impeller plate to pass smoothly during rotation; The rotor impeller plate and the stator plate are both trapezoidal plates provided with vertical grid holes.

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