A high-efficiency circulating turbulent microbubble flotation machine

Abstract

The present invention discloses 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 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 in the present invention can effectively improve the recovery rate of clean coal and improve the overall sorting effect of the equipment. The present invention can greatly reduce the loss of clean coal in 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 an annular shape, and the clean coal foam is evenly distributed and has a slow flow rate when conveyed to the outer end foam tank, and the bubble volume becomes smaller, making the clean coal conveying process more stable, thereby achieving the effect of reducing the loss of clean coal.

Description

Technical Field

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

[0002] With the increasing scarcity of global mineral resources and the continued implementation of green resource development policies, traditional mineral processing technologies are facing unprecedented challenges. Rapid advances in coal mining technology have improved production efficiency but have also led to the challenge of increasingly fine mineral particle size. Furthermore, the increasing content of high ash and intergrown minerals in ore has significantly increased the difficulty of separating and recovering fine-grained minerals. Traditional flotation processes are particularly ineffective when processing fine-grained minerals. Froth flotation, as the most cost-effective separation method in mineral processing, has been widely used in mineral processing plants both domestically and internationally. Its primary equipment includes mechanical flotation cells and flotation columns. While mechanical agitator flotation cells have a long history, their separation efficiency is significantly insufficient when processing fine particles with a diameter of less than 45 microns. Due to their low kinetic energy and low inertial force in the slurry, collision between bubbles and mineral particles and recovery is extremely difficult under the flow conditions of conventional flotation cells.

[0003] As a highly efficient mineral separation equipment, flotation columns have attracted considerable attention in the mineral processing industry for their simple design, flexible operation, and remarkable separation efficiency. This type of equipment is particularly suitable for separating low-grade, fine-grained, and complex mineral resources. In recent years, numerous innovative technologies have emerged globally, including the MTU packed media flotation column developed by Michigan Technological University in the United States, the KFP series flotation columns developed by Poland, and the cyclone-static microbubble flotation column developed by the China University of Mining and Technology. These new flotation columns have demonstrated superior separation accuracy and efficiency for fine-grained, difficult-to-separate minerals compared to traditional mechanical flotation machines. However, it is worth noting that flotation columns still face several technical bottlenecks in practical industrial applications. A key challenge lies in the separation of highly intertwined minerals, making it difficult to maintain a high recovery rate while reducing the ash content of clean coal. Furthermore, the high turbulence intensity within the equipment, which causes the shearing and shedding of bubbles in coarse minerals, reduces the separation efficiency of coarse-grained materials, making it difficult to achieve ideal separation results in coarse particle flotation.

[0004] To address these challenges, the industry is increasingly demanding the development of new flotation equipment, aiming to improve the recovery rate and separation efficiency of fine-particle minerals while reducing energy consumption and minimizing environmental impact. Against this backdrop, turbulent microbubble flotation equipment based on two-stage flotation has emerged, specifically addressing the low recovery rate and poor selectivity in fine-particle coal slime separation. This technology not only optimizes the mineral separation process and improves energy efficiency, but also enhances the overall economic and sustainable nature of the flotation system, bringing innovation to the mineral processing industry. However, existing two-stage flotation machines, such as those described in patent CN116422477A, ​​utilize a system where fine tailings particles naturally settle and aggregate within the inner drum agitation zone. This can lead to insufficient collision between fine particles and bubbles, resulting in severe coarseness in the flotation tailings. Furthermore, the flotation machine's rotating shaft, extending from the upper motor to the lower side of the inner drum, is excessively long, increasing the equipment's operating energy consumption and complicating regular equipment replacement and maintenance. Therefore, there is an urgent need to further improve existing technologies and provide more reliable flotation solutions. 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 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 objectives, the present invention adopts a technical solution: a high-efficiency circulation turbulent microbubble flotation machine, comprising: an outer cylinder, an inner cylinder disposed within the outer cylinder, a rotating shaft disposed within the inner cylinder, a multi-layer coupled radial shear impeller and a high-throughput axial bidirectional conveying impeller disposed sequentially on the rotating shaft from top to bottom, and a lower guide and 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 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. During operation, when viewed from above, 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 provided on the connecting sleeve, wherein the inner impeller plates are arranged obliquely;

[0012] The outer impeller includes several 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 base plate connected to the end of the connecting rod and two flat plates perpendicular to the base 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 provided inside the outer cylinder, 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, the gap between the cylindrical cover and the outer cylinder forms a concentrate collection tank, and a concentrate pipe connected to the concentrate collection tank is provided on the outer wall of the outer cylinder;

[0014] An annular concentrate distribution trough is provided 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 portion of the upper cylinder section has an inverted cone-shaped cylinder portion, and the lower end of the inverted cone-shaped cylinder portion 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 the 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 middlings 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 middlings 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 annularly arranged arc-shaped baffles are provided in the bowl-shaped middling ore collecting trough, wherein the inner ends of the arc-shaped baffles are connected to the lower cylinder section, and the outer ends of the arc-shaped 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-shaped 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. The upper surface of the conical guide block is concave downward to form a guide groove located directly below the lower guide dividing cylinder.

[0021] Preferably, an upper isolation cylinder is provided inside the outer cylinder, the multi-layer coupled radial shear impeller is provided inside the upper isolation cylinder, and the high-throughput axial bidirectional conveying impeller is located in the space between the upper isolation cylinder and the lower guide separation 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, the feed assembly comprising 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 inlet channel, the bottom of the rotating shaft is provided with an air inlet hole, and the bottom of the rotating shaft extends into the lower 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 units include 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, which uses the high-efficiency circulating turbulent microbubble flotation device to perform enhanced flotation of minerals.

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

[0030] (1) The present invention provides a turbulent microbubble flotation machine with high-efficiency circulation, 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 face opposite directions, which promotes the downward sorting of tail coal while conveying the middle ore to the upper part through the outer impeller and flows 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 traditional two-stage flotation machines. At the same time, it is conducive to the replacement and maintenance of equipment parts, effectively reducing the operating costs 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 feed 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 trough is provided with a number of baffles arranged in a circular pattern, which provide upward turbulence for the sinking tailings and promote their overflow into the tailings collection trough for collection. This can reduce the turbulence intensity of the tailings slurry in a short period of time, intensify 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 blocks set in the bowl-shaped tailings collection trough, the slurry falling in the lower guide separation cylinder can flow in a uniform and scattered manner, providing upward momentum and a certain horizontal flow for the medium-sized coal slime particles with mineralized bubbles attached therein, thereby dispersing them into the outer periphery of the lower guide separation cylinder. In conjunction with the lifting force generated by the outer impeller on the outer periphery of the lower guide separation cylinder, these medium-sized coal slime particles can be transported upward again to the upper cylinder section for recycling and re-sorting, thereby improving the flotation product recovery rate.

[0036] (7) The turbulent microbubble flotation machine of the present invention can be combined and used in a stepped arrangement or a stacked arrangement. The stepped arrangement enables the equipment to sweep the tail coal multiple times, which is beneficial to improving the recovery rate of the flotation product; the stacked arrangement can greatly reduce the floor space of the equipment, improve space utilization, and reduce labor maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the cross-sectional structure of the high-efficiency circulating turbulent microbubble flotation machine of Example 1;

[0038] Figure 2 Schematic diagram of the external structure of the high-efficiency circulating turbulent microbubble flotation machine of Example 1;

[0039] Figure 3 Schematic diagram of the internal structure of the high-efficiency circulating turbulent microbubble flotation machine of Example 1;

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

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

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

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

[0044] Figure 8 Schematic diagram of the internal structure of the inner cylinder of Example 1;

[0045] Figure 9This is a schematic diagram of the structure of the material distribution pipe and the upper isolation cylinder in the top view of Example 1;

[0046] Figure 10 The test results of the yield and ash content of clean coal and tail coal of the three flotation equipment TFM, MFC and XFD in the test example are as follows;

[0047] Figure 11 The flotation recovery rate test results of the three flotation equipment TFM, MFC, and XFD in the test case are shown in the figure.

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

[0049] Figure 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—diameter-reducing cover; 12—concentrate collection trough; 13—concentrate pipe; 14—concentrate distribution trough; 15—concentrate conveying trough; 16—bowl-shaped middling collection trough; 17—tailings pipe; 18—conical guide block; 19—upper isolation cylinder; 111—cylindrical cover; 112—conical cover; 161—tailings collection trough; 162—arc-shaped baffle; 163—tailings diversion channel; 181—diversion 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-stop groove; 24—tailings diversion port;

[0053] 31—motor; 32—rotating shaft; 321—air intake channel; 322—air intake 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—feed assembly; 71—feed pipe; 72—annular distribution pipe; 73—distribution pipe. DETAILED DESCRIPTION

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

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

[0060] Example 1

[0061] A high-efficiency circulation turbulent microbubble flotation machine comprises: an outer cylinder 1, an inner cylinder 2 disposed within the outer cylinder 1, a rotating shaft 32 disposed within the inner cylinder 2, a multi-layer coupled radial shear impeller 4 and a high-throughput axial bidirectional conveying impeller 5 disposed sequentially on the rotating shaft 32 from top to bottom, a lower guide and 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 separation tube 6, while the outer impeller 52 forms an upward thrust in the external area of ​​the lower guide separation tube 6.

[0063] The projection of the lower flow guide separator 6 in the horizontal plane is located between the outer periphery of the inner impeller 51 and the inner periphery of the outer impeller 52. In other words, the lower flow guide separator 6 is coaxial with the rotating shaft 32, and the inner diameter of the lower flow guide separator 6 is between the diameters of the inner impeller 51 and 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 in operation, the rotating shaft 32 is driven to rotate in a clockwise direction when viewed from above.

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

[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. During operation, the motor 31 drives the rotating shaft 32 to rotate clockwise (as viewed from above). During rotation, the inner impeller 51 exerts a downward thrust on the slurry below it (primarily the slurry within the lower guide and separation barrel 6), while the outer impeller 52 exerts an upward lift on the slurry below it (primarily the slurry outside the lower guide and separation barrel 6). This generates fluid driving forces in different directions inside and outside the lower guide and separation barrel 6, achieving a localized re-separation effect.

[0067] In this embodiment, the high-throughput axial bidirectional conveying impeller 5 further includes a connecting sleeve 53 fixedly mounted on the rotating shaft 32, and the inner impeller 51 includes a plurality of inner impeller plates 511 arranged in an annular shape and mounted on the connecting sleeve 53. The inner impeller plates 511 are arranged in an inclined manner (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 Figure B 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, which is 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 in the slurry and the bubbles. The interior of the U-shaped cavity can provide sufficient radial driving force to 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 through the anti-rotation groove 221. In this embodiment, a variable diameter cover 11 is provided inside the outer cylinder 1. The variable diameter cover 11 includes a cylindrical cover 111 and a conical cover 112 connected to the bottom of the cylindrical cover 111. The bottom of the conical cover 112 is connected to the inner wall of the outer cylinder 1. The gap between the cylindrical cover 111 and the outer cylinder 1 forms a concentrate collection tank 12. A concentrate pipe 13 connected to the concentrate collection tank 12 is provided on the outer wall of the outer cylinder 1.

[0070] An annular concentrate distribution trough 14 is provided on the inner periphery of the variable diameter cover 11 . 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.

[0071] 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 portion of the upper cylinder section 21 has an inverted cone-shaped cylinder portion 211, and the lower end of the inverted cone-shaped cylinder portion 211 extends into the intermediate cylinder section 22.

[0072] The middle cylinder section 22 is spherical, and a number of anti-rotation grooves 221 are evenly spaced along the circumferential direction on the wall surface of the middle cylinder section 22. 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 due to the action of the spherical middle cylinder section 22.

[0073] 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 separation cylinder 6 is connected to the inner wall of the lower cylinder section 23 through the mounting bracket 61.

[0074] In this embodiment, a bowl-shaped middlings collection trough 16 is provided at the bottom of the outer cylinder 1. A gap between the outer edge of the bowl-shaped middlings collection trough 16 and the inner wall of the side of the outer cylinder 1 forms a tailings collection trough 161. A tailings pipe 17 is provided on the outer wall of the outer cylinder 1 and is connected to the tailings collection trough 161.

[0075] A plurality of annularly arranged arc-shaped baffles 162 are provided in the bowl-shaped middling ore collection trough 16. The inner ends of the arc-shaped baffles 162 are connected to the lower cylinder section 23, and the outer ends of the arc-shaped baffles 162 are cooperatively connected to the inner side walls of the bowl-shaped middling ore collection trough 16. Adjacent arc-shaped baffles 162 form tailings diversion channels 163 that communicate with the tailings diversion port 24.

[0076] 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 162. The upper surface of the conical guide block 18 is concave downward to form a guide groove 181 located directly below the lower guide dividing cylinder 6.

[0077] In this embodiment, an upper isolation cylinder 19 is provided inside the outer cylinder 1, the multi-layer coupled radial shear impeller 4 is provided inside the upper isolation cylinder 19, and the 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.

[0078] 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. 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 generated by each distribution pipe 73 has the same direction.

[0079] In this embodiment, two distribution pipes 73 are included, and the slurry output from the two distribution pipes 73 generates a swirl direction in the clockwise direction, which is the same as the rotation direction of the rotating shaft 32; the swirl feed can cooperate with the multi-layer coupled radial shear impeller 4, so that the slurry and the multi-layer coupled radial shear impeller 4 produce more intense collision and shearing effects.

[0080] The interior of the rotating shaft 32 is hollow to form an air inlet channel 321 . 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 .

[0081] In this embodiment, the multi-layer coupled radial shear impeller 4 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;

[0082] At least two stator plate 192 units 191, the same number as the radial shear impeller 41, are provided 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 in a ring shape to the inner wall of the upper isolating cylinder 19. In this embodiment, there are two stator plate 192 units 191 and two rotor impeller plates 411.

[0083] The radial shear impellers 41 and the stator plate 192 units 191 are vertically staggered, allowing the space between two adjacent stator plates 192 to allow the rotor impeller plates 411 to pass smoothly during rotation. Both the radial shear impellers 41 and the stator plate 192 are trapezoidal plates with vertical grid holes. When the radial shear impellers 41 rotate relative to the stator plate 192 units 191, the rotor impeller plates 411 and the stator plate 192 work together to produce a strong radial shearing effect, which cuts bubbles into a large number of microbubbles. The increase in microbubbles increases the frequency of collisions between fine particles in the slurry and bubbles, significantly improving the mineralization effect.

[0084] It should be noted that, in this embodiment, the flotation objects are fine-grained minerals with a diameter of less than 20 μm.

[0085] The main working process and principle of the turbulent microbubble flotation machine of this embodiment are described below:

[0086] (1) The slurry after slurry adjustment is fed into the feed pipe 71, 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 feed in the upper isolation cylinder 19;

[0087] (2) At the same time, the inner impeller 51 of the high-throughput axial bidirectional conveying impeller 5 is driven to rotate clockwise via the rotating shaft 32, 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. 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 4 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 4, the coal slime particles in the slurry fully collide with the microbubbles, thereby achieving efficient mineralization.

[0088] (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, and meet the rising microbubbles at the lower air inlet 322 to form a countercurrent circulation again, further increasing the collision probability of fine particles and bubbles, and reducing the coarse particle phenomenon in the fine particle separation;

[0089] (4) The fine tailings and some of the middling coal slime particles flow downward into the bowl-shaped middling collection trough 16, and through the action of the guide groove 181 on the conical guide block 18, they evenly scatter toward the periphery of the conical guide block 18. The fine tailings that are not attached to the mineralized bubbles continue to fall and enter the tailings diversion channel 163 through the tailings diversion port 24, and finally overflow into the tailings collection trough 161 for collection, and then are discharged through the tailings pipe 17; some of the middling coal slime particles that are attached to the mineralized bubbles flow to the outside of the lower diversion 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;

[0090] (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 separation cylinder 6 and the inner cylinder 2, and transports 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 steady flow during the conveying of the clean coal; the finely controlled foam in the concentrate distribution trough 14 is then collected into the concentrate collection trough 12 through the concentrate conveying trough 15, and finally flows out from the concentrate pipe 13.

[0091] (6) Furthermore, the baffle in the bowl-shaped middling collecting trough 16 gathers the sinking middlings 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 coal slime particles are transported upward to the upper part of the multi-layer coupled radial shear impeller 4 through the channel between the outer side of the lower guide and separation cylinder 6 and the lower cylinder section 23, forming a recycling and re-sorting of the middling coal slime, thereby improving the flotation product recovery rate and the overall flotation efficiency of the equipment.

[0092] Compared with the prior art, the turbulent microbubble flotation machine with high efficiency circulation provided in this embodiment adopts a double-layer cylinder with inner and outer nesting, 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, which avoids 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 transported 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.

[0093] Test Case

[0094] To further illustrate the present invention, flotation experiments were conducted using the high-efficiency circulating turbulent microbubble flotation machine (with a capacity of 3 L, denoted as TFM) of Example 1. A conventional laboratory flotation machine (XFD-3L, denoted as XFD) and an ultrafine turbulent flow flotation machine (denoted as MFC) having the same structure as Example 1 of CN116422477A (the applicant's previous patent) were used for comparison. The experiments were conducted using the same flotation process parameters and raw coal from the Daizhuang Coal Preparation Plant as the flotation feed.

[0095] The flotation process parameters are as follows: the collector and frother are authentic diesel and octanol, with dosages of 500 g / t and 100 g / t respectively; the flotation feed concentration is maintained at 100 g / L, and the flotation time is 3 min.

[0096] The particle size composition of flotation feed is shown in Table 1 below:

[0097] Table 1 Flotation feed particle size composition

[0098]

[0099] Particle size composition analysis: -0.038mm material accounts for 55.62% of the total sample yield and has an ash content of 44.02%. This high fines content makes it susceptible to fine mud capping and entrainment, hindering conventional flotation separation. Slime content and ash content are unevenly distributed across particle sizes, with the ash content increasing with decreasing particle size. The +0.212mm particle size contains less slime, with an ash content of 5.53%. However, this low-ash slime easily desorbs during flotation separation, coarsening into the flotation tailings and preventing effective recovery, resulting in a low tailings ash content.

[0100] The yield and ash content of clean coal and tail coal of three flotation equipments TFM, MFC and XFD are as follows: Figure 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 Figure 11 shown.

[0101] From the flotation results, it can be seen that TFM has the best effect and the highest tailing ash content. In addition, the flotation kinetics of TFM is faster, which is conducive to reducing the size of the equipment.

[0102] XFD: Conventional laboratory flotation machine (XFD-3L); the clean coal yield is lower than that of TFM, while the tailing ash content is the lowest, and the mineral separation performance is significantly lower than that of TFM;

[0103] MFC: In Example 1 of the patent (CN116422477A), the flotation kinetics of TFM are significantly faster than those of MFC, and TFM has a higher separation efficiency.

[0104] Example 2

[0105] The high-efficiency circulating turbulent microbubble flotation machine of the present invention can be used by arranging a plurality of devices in combination. This embodiment illustrates two arrangements: a stepped arrangement and a stacked arrangement.

[0106] 1. Figure 12 The diagram shows the stepped arrangement of multiple turbulent microbubble flotation equipment:

[0107] The flotation cells are arranged in a diagonal, stepped configuration. The lower end of the tailings pipe 17 of the upper flotation cell is horizontally aligned with the upper end of the feed pipe 71 of the lower flotation cell, and the two ports are connected via flange fittings. After completing primary mineralization sorting in the upper flotation cell, the slurry flows from the tailings pipe 17 of the upper flotation cell and then flows into the feed pipe 71 of the lower flotation cell, where it undergoes secondary mineralization sorting. This stepped arrangement facilitates multiple scavenging of tailings from the flotation product, increasing the flotation mineral recovery rate and improving the overall sorting performance of the equipment.

[0108] 2. Figure 13 The stacking arrangement of multiple turbulent microbubble flotation equipment is shown in the figure:

[0109] The flotation equipment is stacked vertically, with the feed pipes 71 and tailings pipes 17 of the upper and lower flotation equipment vertically aligned. The tailings pipe 17 of the upper flotation equipment is connected to the feed pipe 71 of the lower flotation equipment, and the equipment is arranged in this order. This stacked arrangement helps reduce the floor space occupied by multiple flotation machines, improves equipment space utilization, reduces labor costs for maintenance of multiple equipment, and reduces the difficulty of construction layout, further increasing the production profit of the equipment.

[0110] In the description of the present invention, it should 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" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying 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.

[0111] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. 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, wherein the inner impeller and the outer impeller face opposite directions, so that when the rotating shaft rotates, the inner impeller generates a downward thrust in the inner area of ​​the lower flow guide separation cylinder, while the outer impeller generates an upward thrust in the outer area of ​​the lower flow guide separation cylinder; 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 provided on the connecting sleeve, wherein the inner impeller plates are inclined; The outer impeller includes several 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 base plate connected to the end of the connecting rod and two flat plates perpendicular to the base 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.

2. The high-efficiency circulating turbulent microbubble flotation machine according to claim 1, characterized in that: The projection of the lower flow guide separation cylinder in the horizontal plane is located 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. During operation, when viewed from above, the rotating shaft is driven to rotate counterclockwise.

4. The high-efficiency circulating turbulent microbubble flotation machine according to claim 3, characterized in that: A variable diameter cover is provided 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. The gap between the cylindrical cover and the outer cylinder forms a concentrate collection tank. A concentrate pipe connected to the concentrate collection tank is provided on the outer wall of the outer cylinder; An annular concentrate distribution trough is provided 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.

5. The high-efficiency circulating turbulent microbubble flotation machine according to claim 4, characterized in that: The inner cylinder includes an upper cylinder section, an intermediate cylinder section and a lower cylinder section from top to bottom. The lower portion of the upper cylinder section has an inverted cone-shaped cylinder portion, and the lower end of the inverted cone-shaped cylinder portion extends into the intermediate cylinder 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 the 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.

6. The high-efficiency circulating turbulent microbubble flotation machine according to claim 5, characterized in that: 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 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; A plurality of annularly arranged arc-shaped baffles are provided in the bowl-shaped middling ore collecting trough, wherein the inner ends of the arc-shaped baffles are connected to the lower cylinder section, and the outer ends of the arc-shaped 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-shaped 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. The upper surface of the conical guide block is concave downward to form a guide groove located directly below the lower guide dividing cylinder.

7. The high-efficiency circulating turbulent microbubble flotation machine according to claim 6, characterized in that: An upper isolation cylinder is provided inside the outer cylinder, the multi-layer coupled radial shear impeller is provided inside the upper isolation cylinder, and the high-throughput axial bidirectional conveying impeller is located in the space between the upper isolation cylinder and the lower guide separation cylinder.

8. The high-efficiency circulating turbulent microbubble flotation machine according to claim 7, characterized in that: The device further comprises a feed assembly and a motor 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 a circumferential tangent direction; The interior of the rotating shaft is hollow to form an air inlet channel, the bottom of the rotating shaft is provided with an air inlet hole, and the bottom of the rotating shaft extends into the lower guide separation cylinder.

9. The high-efficiency circulating turbulent microbubble flotation machine according to claim 7, 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 units include 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.

Images