CN222369334U

CN222369334U - Micro-nano bubble generator for flotation separation of fine minerals

Info

Publication number: CN222369334U
Application number: CN202421102537.4U
Authority: CN
Inventors: 刘联胜; 解珺; 段润泽; 杨华
Original assignee: Hebei University of Technology
Current assignee: Hebei University of Technology
Priority date: 2024-05-21
Filing date: 2024-05-21
Publication date: 2025-01-21
Anticipated expiration: 2034-05-21

Abstract

The utility model is a micro-nano bubble generating device suitable for fine mineral flotation separation, comprising internal parts, external parts and nozzles that can be detachably connected by thread, the lower space formed after the external parts are connected to the internal parts is a bubble flow mixing chamber, a stainless steel wire mesh is embedded in the bubble flow mixing chamber, and the aspect ratio of the bubble flow mixing chamber is between 0.5:1 and 1.0:1; a bubble generator is also arranged above the two-phase mixing cyclone, and the bubble hydraulic regulator is composed of a plurality of identical passages, which are radially and evenly distributed on the cross section of the internal parts, and the plurality of identical passages are all connected to the gas channel connected to the gas inlet. The micro-nano bubbles formed by the utility model are uniform and stable, simple in structure, easy to repair and replace, low in working pressure, and wide in applicability, which solves the problem of small bubble range adjustment of the existing micro-nano bubble generating device.

Description

Micro-nano bubble generation device suitable for fine mineral flotation separation

Technical Field

The utility model belongs to the technical field of fine mineral flotation separation physicochemical, and particularly relates to a micro-nano bubble generation device suitable for fine mineral flotation separation.

Background

In the field of fine mineral flotation separation physicochemical, the influencing factors of the fine mineral particle flotation performance are mainly the collision and adhesion between bubbles and fine mineral particles, the bubble size and the particle size. Wherein, the jet flow generates micro-nano bubbles, and the advantages of small occupied area, compact structure, high processing capacity and the like are widely applied. The main mechanism is that the liquid is conveyed to the ejector through the circulating pump, and the surrounding air is taken away together when the liquid is ejected from the ejector at high speed, the air is continuously sucked into the water, fully mixed with the water and subjected to energy exchange, and simultaneously is cut into tiny bubbles. Commonly used ejectors are pressure nozzles and venturi nozzles. However, the existing jet mixing has the problems of high structural design difficulty, high energy consumption, difficult control of bubble size, and easy corrosion of a conventional nozzle due to cavitation, cavitation is a hydrodynamic phenomenon of bubble formation, development, shrinkage and final collapse, and occurs when the partial pressure in a liquid flow system is lower than the saturated vapor pressure at the corresponding temperature, and the particle size distribution of mineral flotation in the actual production process is wider.

Therefore, the application provides a micro-nano bubble generating device suitable for fine mineral flotation separation, the nozzle of the device forms bubbles inside, the partial pressure is not lower than the saturated vapor pressure at the corresponding temperature, so cavitation phenomenon is not generated, the energy consumption is low, the size distribution of the bubbles is wide, and the device is easy to control.

Disclosure of utility model

Aiming at the defects, the utility model aims to provide a micro-nano bubble generation device for fine mineral flotation separation, which solves the technical problems of high jet mixing jet flow difficulty, wide bubble size distribution, difficult control, easy corrosion and higher energy consumption.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

The micro-nano bubble generation device suitable for fine mineral flotation separation comprises an inner part 1, an outer part 2 and a spray head 3 which are detachably connected in a threaded manner, wherein a gas introduction port 11 is formed in the top of the inner part 1, a two-phase mixing cyclone 13 is arranged at the lower part, a bubble water regulator 12 is circumferentially arranged on the inner part above the two-phase mixing cyclone 13, a liquid introduction port 21 is formed in the outer part 2, a bubble flow mixing chamber 5 is formed in the lower space formed by connecting the outer part 2 and the inner part 1, a stainless steel wire mesh 6 is embedded in the bubble flow mixing chamber 5, and the length-diameter ratio of the bubble flow mixing chamber is between 0.5:1 and 1.0:1;

The bubble generator is in an inverted disc shape, the inner core of the bottom of the inverted disc is fixed above the two-phase mixing cyclone 13 through a spring, circumferential grooves with the same number as that of the passages of the bubble water regulator are uniformly distributed on the side surface of the inverted disc, the opening width of the circumferential grooves is smaller than the diameter of the passages of the bubble water regulator, and the positions of the circumferential grooves are opposite to the setting positions of the passages of the bubble water regulator;

The spray head comprises a spray head body and a spray nozzle, wherein the spray nozzle comprises a shrinkage reducing section 3A and a straight line section 3B, the angle between the shrinkage reducing section 3A and the central axis of the spray head is 45-60 degrees, and the height of the straight line section on the central axis is 1-2mm.

Further, the straight line segment 3B includes a central straight line segment and a peripheral straight line segment, the central straight line segment is located on the axis, the peripheral straight line segments are uniformly distributed in a circumference with the central straight line segment as the center, the central straight line segment and the peripheral straight line segment can be parallel to each other or form a certain included angle, the number of the peripheral straight line segments can influence the flow of the liquid suction inlet and the gas suction inlet, the upper limit of the jet height is 1m, and the inclination range of the peripheral straight line segment is 0-60 °.

Further, the opening width of the circumferential groove is 0.8-1.2mm, the diameter of a passage of the bubble water regulator 12 is 2-3mm, the outer tray bottom and the side surface of the bubble generator are arc transition cambered surfaces, and the aperture range of the stainless steel wire mesh is 0.07-0.4 mm.

Further, the device comprises various internal parts of the bubble water regulator 12 with different passage diameters, the bubble water regulator is divided into three types of 1mm, 2mm and 3mm according to the different passage diameters, the spray head is provided with various specifications, namely a single-hole spray head 31, a SA0 porous spray head 32, a SA45 porous spray head 33 and a SA60 porous spray head 34, the single-hole spray head is provided with only one vertical outlet, the porous spray head is provided with a plurality of outlets which form oblique inclination angles with the axis of the spray head besides the central vertical outlet, one ends of the outlets are connected with the shrinkage reducing section of the spray head, the other ends of the outlets are positioned on the section of the lower end of the spray head, SA45 is formed at an angle of 45 degrees with the central axis of the spray head, SA60 is formed at an angle of 60 degrees with the central axis of the spray head, and SA0 is formed at an angle of 0 degrees with the central axis of the spray head.

Further, the gas flow rate of the gas suction inlet is 0.06-0.16m ³/h, and the liquid flow rate supplied to the circulating liquid suction inlet is 2-10kg/h;

When micro-nano bubbles with small size are needed in the flotation process, the mass flow of the gas is smaller, the spring is positioned at a static fixed position, the gas obliquely enters a first-stage mixing chamber between an inner part and an outer part above the two-phase mixing cyclone through a passage of the bubble water regulator through a circumferential groove on the bubble generator 4, and when micro-bubbles with full size range are needed in the flotation process, the spring below the bubble generator is in a compressed state by increasing the mass flow of the gas, so that the inclination degree of the circumferential groove of the bubble generator and the bubble water regulator is changed, and the gas can gradually and directly enter the first-stage mixing chamber through the bubble water regulator 12;

the bubble flow mixing chamber 5 is internally embedded with a 304 stainless steel wire mesh 6, bubble diameters are adjusted according to different stainless steel wire mesh pore diameters, the bubble diameters gradually decrease along with the decrease of the stainless steel wire mesh 6 pore diameters, the small-scale bubble occupation ratio decreases firstly and then increases, the small-scale bubble quantity increases, and the coalescence probability of the small-scale bubbles is larger than the crushing probability;

Due to the effects of internal and external pressure differences and speed gradients, bubbles are broken into smaller micro-nano bubbles when bubble flow passes through the outlet of the spray nozzle, and the retention time of the micro-nano bubbles is prolonged from 40min to 1h due to the entrainment effect of a jet boundary layer, so that the flotation separation efficiency of fine minerals is enhanced.

Compared with the prior art, the utility model has the beneficial effects that:

1) The size of the micro-nano bubbles can be controlled on the outlet nozzle 3 and the bubble generator 4 according to the physical properties of the liquid, so that the micro-nano bubbles are more uniformly distributed, and the micro-nano bubble flotation device is suitable for various working conditions, so that the bubble size distribution is wider, and the mineral flotation separation is facilitated.

2) The micro-nano bubble jet angle can be adjusted by adopting different spray heads 3, the jet cone angle is increased, and the angle can reach 60 degrees, so that the micro-nano bubble jet angle is suitable for various containers.

3) The turbulence of the jet vortices in the two-phase mixing cyclone 13 enhances the uniformity of the bubble flow. The 304 stainless steel wire mesh 6 (the aperture of the 304 stainless steel wire mesh is 11, the range is 0.07mm to 0.4mm, the aperture is 0.07mm,0.09mm,0.11mm,0.12mm,0.15mm,0.16mm,0.19mm,0.24mm,0.27mm,0.31mm and 0.4mm micro-nano bubble diameters are reduced along with the reduction of the aperture, and the distribution of micro-nano bubble sizes (bubble diameters are smaller than 100 mu m) is the largest when the aperture is 0.11 mm) has the same effect.

4) The utility model is the reverse application of the bubble atomizing nozzle, and compared with other bubble generating devices, the device has low energy consumption, wide application and convenient adjustment. The spray head has simple structure, easy replacement, difficult blockage and cavitation corrosion, and prolonged service life.

The utility model is suitable for a micro-nano bubble generation device for fine mineral flotation separation, which is a micro-nano bubble generation device with low energy consumption (reducing power consumption and air consumption), small flow, jet cone angle and adjustable bubble size distribution. Compared with a Venturi nozzle and a pressure nozzle, the micro-nano bubble generating device provided by the utility model has the advantages that the energy consumption is 6.53 multiplied by 10 ^-4 kW.h, and the energy consumption is reduced by 23% and 29% respectively. The spray cone angle is realized by changing different spray heads 3, the spray cone angle of a single Kong Pentou spray head 31 is 29 degrees, the spray cone angle of a SA0 porous spray head 32 is 53 degrees, the spray cone angle of a SA45 porous spray head 33 is 98 degrees, and the spray cone angle of a SA60 porous spray head 34 is 135 degrees. The total outlet cross-sectional area of the spray head is the same and thus the flow characteristics are the same. When the gas mass flow rate is 1.05kg/h and the circulating liquid mass flow rate is 7kg/h, the generated micro-nano diameter is minimum and is 0.76 mu m. And the size distribution of micro-nano bubbles is different along with the difference of the aperture of the 304 stainless steel wire mesh 6 and the mass flow ratio of gas to liquid.

The micro-nano bubble generating device has the advantages of uniform and stable formed micro-nano bubbles, simple structure, convenient maintenance and replacement, low working pressure and wide applicability, and solves the problem of small bubble range adjustment of the existing micro-nano bubble generating device.

Drawings

FIG. 1 is an assembly structure diagram of parts of a micro-nano bubble generating device suitable for fine mineral flotation separation;

In the drawings, an inner part 1, an outer part 2, a spray head 3, a bubble generator 4, a bubble flow mixing chamber 5,304 and a stainless steel wire mesh 6.

FIG. 2 is a block diagram of internal components of a micro-nano bubble generating apparatus suitable for fine mineral flotation separation;

In the drawing, a gas inlet 11, a bubble water regulator 12, and a two-phase mixing cyclone 13 are shown.

FIG. 3 is a block diagram of external parts of a micro-nano bubble generating device suitable for fine mineral flotation separation;

in the drawing, a circulating liquid introduction port 21 is provided.

Fig. 4 is a schematic diagram of a different spray head structure of a micro-nano bubble generating apparatus suitable for fine mineral flotation separation, wherein 31 is a single-hole spray head, 32 is a SA0 porous spray head, 33 is a SA45 porous spray head, 34 is a SA60 porous spray head, the spray cone angle (out spray range) of a single Kong Pentou is 29 °, the spray cone angle of the SA0 porous spray head 32 is 53 °, the spray cone angle of the SA45 porous spray head 33 is 98 °, and the spray cone angle of the SA60 porous spray head 34 is 135 ° (two oblique spray forming ranges).

Fig. 5 is a schematic structural view of the bubble water regulator 12, a is a plan view, and b is a front view.

FIG. 6 is a block diagram of a bubble generator in a micro-nano bubble generating apparatus suitable for fine mineral flotation separation;

in the drawings, a is a top view, and b is a front view

Fig. 7 is a normal distribution diagram of bubble diameters.

FIG. 8 is a graph of cumulative percentage of bubble diameters.

Fig. 9 is a particle size distribution of a fine mineral flotation separation feed.

Fig. 10 is a graph of fine mineral flotation separation efficiency.

Detailed Description

The present utility model is further explained below with reference to examples and drawings, but is not limited thereto.

The utility model is suitable for the field of fine mineral flotation separation and physical chemistry, and separates useful fine minerals from waste rocks, impurities and other useless minerals. The initial turbulent kinetic energy of the jet was 10m ²/s².

The micro-nano bubble generating device (see figures 1-6) is suitable for fine mineral flotation separation, and is formed by connecting an inner part 1, an outer part 2 and a spray head 3 in sequence in a screw thread rigid mode. The inner part 1 is provided with a gas inlet 11, a bubble water regulator 12 and a two-phase mixing cyclone 13, and the bubble water regulator 12 and the two-phase mixing cyclone 13 are integrally processed. The two-phase mixing cyclone 13 has an inclination angle of 45 degrees, a height of 6mm and an outlet side length of 2mm, and is provided with four cyclone grooves on the side surface of the lower part of the inner part.

The outer part 2 is provided with a liquid introduction port 21 and a bubble flow mixing chamber 5. The height of the liquid inlet 21 is 5mm from that of the bubble water regulator 12, and the liquid inlet is positioned above the bubble water regulator 12. The gas inlet 11 and the liquid inlet 21 are connected with the gas pipe and the liquid pipe by screw connection quick connectors. The bubble flow mixing chamber 5 is a space formed between the outer part 2 and the inner part 1 after connection. The length-diameter ratio of the bubble flow mixing chamber is between 0.5:1 and 1.0:1. The stainless steel wire mesh 6 is embedded 304 in the bubble flow mixing chamber 5 and is used for cutting large-scale bubbles, and meanwhile, the bubbles are uniformly distributed in the bubble flow mixing chamber, so that the purposes of adjusting the size and distribution of the bubbles are achieved.

A bubble generator 4 is also arranged in the gas introducing channel of the internal part above the two-phase mixing cyclone 13, the bubble generator is in an inverted disc shape (see fig. 6), the inner core of the disc bottom of the inverted disc is fixed above the two-phase mixing cyclone 13 through a spring, circumferential grooves with the same number as that of the passages of the bubble water regulator are uniformly distributed on the side surface of the inverted disc, the opening width of the circumferential grooves is smaller than the diameter of the passages of the bubble water regulator, and the positions of the circumferential grooves are opposite to the setting positions of the passages of the bubble water regulator.

The spray heads are mainly four types, namely a single Kong Pentou, a SA0 porous spray head 32, a SA45 porous spray head 33 (45 DEG) and a SA60 (the included angle between oblique lines and a vertical axis is 60 DEG) porous spray head 34, the spray heads are detachably arranged, and proper spray heads are selected according to requirements. The spray head comprises a spray head body and a spray nozzle, wherein the spray nozzle comprises a shrinkage reducing section 3A and a straight line section 3B, and the space from the straight line section to the stainless steel wire mesh 6 in the section of the stainless steel wire mesh 6 in the drawing 4 is the shrinkage reducing section 3A. The angle of the reduction section 3A to the horizontal is 30 deg. and the height is 5mm. When the diameter of the bottom of the silk screen is increased, the height of the shrinking section is lower, the bubbles can collide with the wall, and the size of the bubbles can be increased. The straight line segment 3B includes a central straight line segment and a peripheral straight line segment, the central straight line segment is located on the axis, the peripheral straight line segment is uniformly distributed in a circumference with the central straight line segment as the center, and 5 outlet holes (such as the SA45 porous spray head 33 and the SA60 porous spray head 34) are arranged on the circumference in total. In the drawing, the central straight line segment and the peripheral straight line segment of the SA0 multi-hole shower head 32 are parallel to each other, and each has an angle of 90 DEG with respect to the horizontal plane. The number of the peripheral straight line segments can influence the flow of the liquid suction inlet and the gas suction inlet, the upper limit of the jet height is 1m, the larger the inclined range of the peripheral straight line segments is, the larger the jet angle is, the wider the jet range is, and the jet range is adjusted by adjusting the inclined angle of the peripheral straight line segments. The height of the middle straight line segment is 1-2mm. In the figure, a single Kong Pentou is a single straight line segment, the gas flow is 0.163/h, the liquid is 10kg/h, and the lowest jet height is 50mm. Different spray heads show different spray cone angles, and the cone angles are adjustable by changing different spray heads 3.

In this embodiment, the opening width of the circumferential groove is about 1mm, the diameter of the opening of the bubble water regulator 12 is about 2mm, the bubble generator is in the shape of an inverted disk, the bottom and the side of the external disk are arc transition cambered surfaces, and the flow resistance is reduced.

The bubble generator is made of corrosion-resistant metal or alloy material, and the elastic modulus of the spring is 93E/GPa.

The utility model provides a micro-nano bubble generation device suitable for fine mineral flotation separation based on a bubble atomization mechanism and a turbulent jet flow theory. The high pressure gas and the circulating liquid are cross-mixed to form a two-phase bubble flow, and the bubble size in the bubble flow is controlled by the bubble generator 4. When micro-nano bubbles with small size are needed in the flotation process, the mass flow of gas is small, the spring is positioned at a static fixed position, and the gas obliquely enters a primary mixing chamber (a cavity between an inner part and an outer part above the two-phase mixing cyclone) through a passage of a bubble water regulator through a circumferential groove on the bubble generator 4. When micro-bubbles in the full-size range (both micro-nano bubbles and large bubbles) are needed in the flotation process, the spring below the bubble generator is in a compressed state by increasing the gas mass flow, so that the inclination degree of the circumferential groove of the bubble generator and the bubble water regulator is changed, and gas can gradually and directly enter the primary mixing chamber through the bubble water regulator 12.

In addition, micro-nano bubbles can also be controlled by the bubble water regulator 12. The bubble water regulator 12 is classified into three types of 1mm,2mm and 3mm according to the passage diameter, and the diameter of the micro-nano bubbles finally generated is reduced as the diameter of the bubble water regulator is reduced. After passing through the two-phase mixing cyclone 13, the two-phase bubble flow generates rotary shearing turbulence under the action of centrifugal force, and the bubbles start to accelerate tearing to form centrifugal bubble flow.

The stainless steel wire mesh 6 is embedded 304 in the bubble flow mixing chamber 5, reducing the bubble size and promoting uniform bubble flow distribution. The 304 stainless steel wire mesh 6 adjusts the bubble diameter mainly according to the difference of the pore diameters. With the reduction of the aperture of the 304 stainless steel wire mesh 6, the diameters of bubbles are gradually reduced, the small-scale bubble occupancy ratio is firstly reduced and then increased, and the main reason is that the number of the small-scale bubbles is increased, and the coalescence probability of the small-scale bubbles is larger than the crushing probability. The diameter of the 304 stainless steel wire mesh is 11, and the range is 0.07mm-0.4mm. When the bubble water regulator is 1mm type and the aperture of the 304 stainless steel wire mesh is 0.11mm, the ratio of small-scale bubbles (the diameter of generated micro-nano bubbles is less than or equal to 100 mu m) can reach 96% at maximum. The centrifugal bubble flow is sheared and equalized through the 304 stainless steel wire mesh 6 to form discrete bubble flow. The bubble flow breaks into smaller micro-nano bubbles as they pass through the nozzle outlet due to the internal and external pressure differences and the velocity gradient. The spray heads are convenient to detach and replace, and micro-nano bubbles are uniformly distributed by replacing spray heads in different forms. Entrainment of the jet boundary layer (5 cm downstream of the nozzle) resulted in an increase in the residence time of micro-nano bubbles from 40min to 1h, thereby enhancing the fine mineral flotation separation efficiency.

The gas inlet and the liquid inlet are in threaded connection with the quick connector and sealed by an O-shaped rubber ring. The spray head is in threaded rigid connection with an external part. The inner part is rigidly connected with the outer part by a rigid thread. All threaded connection positions are provided with O-shaped rubber rings, so that leakage of gas and liquid is prevented.

The working pressure of the fluid in the gas suction inlet and the liquid suction inlet is 0.1-0.6MPa (the existing air bubble can not form jet flow under 0.1 MPa), and compared with the case that the flotation separation of the same fine minerals reaches 95% (the existing jet flow and air bubble separation device is compared with an integrated device), the required pressure is smaller, and the effect is better. The gas flow rate supplied to the gas suction inlet is 0.06-0.16m ³/h, and the required gas quantity is obviously much smaller than that of the existing flotation separation device. The flow rate of the liquid supplied to the circulating liquid suction inlet is 2-10kg/h, and in this embodiment, the pressure is given to both air and water, and bubbles are formed in the cyclone tank, so that the effect is better than that of the conventional separation device which only gives air pressure. Because the application mixes in the bubble-shaped mixing chamber 5, such that the pressure differential increases, which contributes to the formation of a jet, bubbles are already formed at the mixing chamber orifice, and the size of the bubbles is further reduced by the wire mesh, thereby forming an effective jet.

The method is realized in that high-pressure air enters the air inlet 11 through the air pipeline, liquid enters the liquid inlet 21 through the liquid pipeline, high-pressure air (entering the inner hole of the inner part through the air inlet) and liquid (entering through the liquid inlet and entering the bubble generator 4 through the bubble water regulator 12) are mixed in the bubble generator 4 in a cross mode to form bubbles, and the bubble size of the bubbles can be controlled by the bubble water regulator 12. The bubbles then enter the bubble flow mixing chamber 5 tangentially through the two-phase mixing cyclone 13. The two-phase mixed fluid generates rotary shearing turbulence motion, so that the turbulence shearing force is enhanced, and the bubble size is reduced. The bubbles are rotated along the wall surface of the bubble flow mixing chamber 5 (the inner wall surface of the housing 2) by centrifugal action.

FIG. 7 is a normal distribution diagram of bubble diameters at different length-diameter ratios and FIG. 8 is a cumulative percentage diagram of bubble diameters, and it can be seen from the diagram that bubbles of 0-200 μm can be generated, the bubble distribution is wider, and more bubbles of 0-20 μm are beneficial to mineral concentration. When the length-diameter ratio of the bubble flow mixing chamber 5 is 0.5:1, the action time of turbulent shearing force on bubbles is short, the bubble breaking probability is limited, small bubbles generated by jet flow account for smaller bubbles, the diameter of the bubbles is smaller than 70 mu m and accounts for 86% (see figure 8), the fine mineral flotation efficiency is 72% (see working condition 1 in figure 10, the size distribution of solid particles in working condition 1 in figure 9 is mainly 50 mu m), and the fine mineral flotation efficiency is improved by 20% compared with the venturi nozzle jet flow. As the aspect ratio of the bubble flow mixing chamber 5 increases, the bubble breaking probability increases. When the length-diameter ratio is increased to 0.9:1, 94% of bubbles are smaller than 50 μm, the fine mineral flotation efficiency is about 82% (see the condition of 0.9 corresponding to the working condition 1 in fig. 10), and the fine mineral flotation efficiency is improved by 46.5% compared with the venturi nozzle jet. When the length-diameter ratio of the bubble flow mixing chamber 5 is continuously increased, partial broken small bubbles are mutually fused into larger bubbles, and when the length-diameter ratio is increased to 1.0:1, the ratio of the bubbles smaller than 50 mu m is reduced to 91%, the fine mineral flotation efficiency is 79%, and compared with the venturi nozzle jet flow, the fine mineral flotation efficiency is improved by 40.2%.

To promote uniform bubble flow distribution, a stainless steel mesh is embedded 304 in the bubble flow mixing chamber 5. The 304 stainless steel mesh further cuts the bubbles in the bubble stream into smaller scale bubbles forming a discrete bubble stream. The discrete bubble flow is accelerated by the converging section of the spray head 3. At the nozzle, the bubbles expand and break up into microbubbles due to the large pressure gradient, and the discrete bubble flow forms a jet of microbubbles. The velocity gradient discontinuities between the microbubble jet and the surrounding stationary fluid generate vortices, entraining the surrounding fluid into the jet boundary layer (from outside the jet boundary layer into the jet boundary layer), causing the microbubbles to move, deform and collapse continuously within the external liquid system to generate micro-nanobubbles. Meanwhile, due to entrainment of a jet boundary layer, micro-nano bubbles can form back mixing, so that the residence time of the micro-nano bubbles is prolonged, and the flotation separation efficiency of fine minerals is enhanced.

In the utility model, particles are mixed with liquid to form turbid liquid, and small solid particles are dispersed in the liquid. Micro-nano bubbles generated by jet flow are injected into turbid liquid and contact with the surfaces of target mineral particles. Adsorption of micro-nano bubbles to the surface of mineral particles results in interactions between the bubbles and the mineral. This interaction is achieved by hydrophobic interactions or electrochemical interactions, which promote the formation of bubble-mineral complexes with the mineral particles. Due to the buoyancy of the bubbles, the bubble-mineral compound is brought to the turbid liquid surface by the micro-nano bubbles to form scum. Thus, the target minerals are separated from the waste rocks and other impurities, and the purpose of flotation separation is achieved. Compared with the common micro-nano air flotation, the micro-nano bubbles generated by the device have higher adsorption capacity and faster flotation speed (each bubble is distributed more widely and jet convolution is generated), so that fewer flotation agents can be used in the flotation process, the use amount of chemical agents is reduced, and the production cost is reduced. And compared with the traditional bubble generation device, the energy consumption is lower, and the energy utilization efficiency is improved. Micro-nano bubbles generated by the jet are typically formed by diffusing gas microbubbles in a liquid at high velocity. The high velocity jet provides sufficient power to create turbulence in the liquid, increasing the degree of mixing of the liquid. So that the micro-nano bubbles are uniformly dispersed into the liquid.

The device of the utility model firstly controls the content of the gas and the concentration of the bubbles in the mixture by adjusting the mass flow ratio of the gas and the liquid and utilizing the bubble generator. The size of the bubbles produced is then adjusted by adjusting the structural parameters of the device (length-diameter ratio of the mixing chamber, number of nozzle outlets), adjusting the size of the mixing zone. Fig. 7 and 8 show the effect of aspect ratio on normal distribution and cumulative percentage of bubble diameter ejected from a bubble atomizing nozzle in water, and fig. 10 shows the flotation separation efficiency curve of fine minerals. The results show that for smaller particle size distributions (e.g., 50 μm for the solid particulate size distribution of regime 1), the flotation separation efficiency is highest at an aspect ratio of 0.9. For flotation processes with smaller particle size but larger distribution (such as conditions 2 and 3 where the size distribution of the solid particles is mainly 56 μm and 100 μm), the flotation separation efficiency is significantly increased. When 90% of particles have a particle size smaller than 150 microns and are distributed more widely (the size distribution of solid particles in working condition 4 is mainly 158 microns), the flotation separation efficiency of the device can reach 96%.

The utility model is applicable to the prior art where it is not described.

Claims

1. The micro-nano bubble generation device suitable for fine mineral flotation separation comprises an inner part, an outer part and a spray head which are detachably connected in a threaded manner, wherein the top of the inner part is provided with a gas introduction port, a two-phase mixing cyclone is arranged at the lower part, a bubble water regulator is circumferentially arranged on the inner part above the two-phase mixing cyclone, the outer part is provided with a liquid introduction port, a lower space formed by connecting the outer part and the inner part is a bubble flow mixing chamber, and a stainless steel wire mesh is embedded in the bubble flow mixing chamber, and the micro-nano bubble generation device is characterized in that the length-diameter ratio of the bubble flow mixing chamber is between 0.5:1 and 1.0:1;

The bubble generator is of an inverted disc shape, a disc bottom inner core of the inverted disc is fixed above the two-phase mixing cyclone through a spring, circumferential grooves with the same number as that of the passages of the bubble water regulator are uniformly distributed on the side face of the inverted disc, the opening width of the circumferential grooves is smaller than the diameter of the passages of the bubble water regulator, and the positions of the circumferential grooves are opposite to the setting positions of the passages of the bubble water regulator.

2. The micro-nano bubble generating apparatus according to claim 1, wherein the spray head comprises a spray head body and a spray nozzle, the spray nozzle comprising a tapered section and a straight section;

The straight line segments comprise a central straight line segment and peripheral straight line segments, the central straight line segment is positioned on an axis, the peripheral straight line segments are uniformly distributed in a circumference manner by taking the central straight line segment as a center, the central straight line segment and the peripheral straight line segments can be mutually parallel or form a certain included angle, the upper limit of jet height is 1m, and the inclination range of the peripheral straight line segments is 0-60 degrees.

3. The micro-nano bubble generating device according to claim 1, wherein the opening width of the circumferential groove is 0.8-1.2mm, the passage diameter of the bubble water regulator is-3 mm, the outer tray bottom and the side surface of the bubble generator are arc transition cambered surfaces, and the aperture range of the stainless steel wire mesh is 0.07-0.4 mm.

4. The micro-nano bubble generating device according to claim 1, wherein the device comprises various internal parts of bubble water regulators with different passage diameters, the bubble water regulators are divided into three types of 1mm, 2mm and 3mm according to the passage diameters, the spray head is provided with various specifications, namely a single-hole spray head, a SA0 porous spray head, a SA45 porous spray head or a SA60 porous spray head, the single-hole spray head is provided with only one vertical outlet, the porous spray head is provided with a plurality of outlets which are inclined at an inclined angle to the spray head axis in addition to the central vertical outlet, one end of each of the plurality of outlets is connected with a tapered section of the spray head, one end of each of the outlets is positioned on the cross section of the lower end of the spray head, SA45 is positioned at an angle of 45 DEG to the spray head central axis, SA60 DEG to the spray head central axis, and SA0 is positioned at an angle of 0 DEG to the spray head central axis.