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

Abstract

The utility model relates to a micro-nano bubble generating device suitable for fine mineral flotation separation, which comprises an internal part, an external part and a spray head which are in detachable threaded connection, a lower space formed after the external part is connected with the internal part is a bubble flow mixing chamber, and a stainless steel wire mesh is embedded in the bubble flow mixing chamber. The length-diameter ratio of the bubble flow mixing chamber is (0.5: 1)-(1.0: 1); a bubble generator is further arranged above the two-phase mixing cyclone, the bubble hydraulic regulator is composed of a plurality of identical passages, the identical passages are evenly distributed on the cross section of the internal part in a radial shape, and the identical passages are all communicated with a gas channel communicated with the gas inlet. Micro-nano bubbles formed by the micro-nano bubble generating device are uniform and stable, the micro-nano bubble generating device is simple in structure, convenient to maintain and replace, low in working pressure and wide in applicability, and the problem that an existing micro-nano bubble generating device is small in bubble range adjustment is solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of physical chemistry of fine mineral flotation separation, and in particular relates to a micro-nano bubble generating device suitable for fine mineral flotation separation. Background Art

[0002] In the field of physical chemistry of fine mineral flotation separation, the factors affecting the flotation performance of fine mineral particles are mainly the collision and adhesion between bubbles and fine mineral particles, bubble size and particle size. Among them, jet-generated micro-nano bubbles are widely used due to their small footprint, compact structure and large processing capacity. Its main mechanism is that the liquid is transported to the ejector through a circulating pump, and the surrounding air is taken away when it is ejected from the ejector at high speed. The air is continuously sucked into the water, fully mixed with the water and energy exchanged, and at the same time cut into tiny bubbles. Commonly used ejectors are pressure nozzles and Venturi nozzles. However, the current structural design of jet mixing is difficult, the energy consumption is high, the bubble size is difficult to control, and the conventional nozzle is prone to corrosion due to cavitation. Cavitation is a fluid dynamic phenomenon in which bubbles form, develop, shrink and eventually collapse. It occurs when the partial pressure in the liquid flow system is lower than the saturated vapor pressure at the corresponding temperature, and the particle size distribution of mineral flotation in actual production is relatively wide.

[0003] Therefore, the present application provides a micro-nano bubble generating device suitable for flotation separation of fine minerals, in which the nozzle forms bubbles inside, and the partial pressure will not be lower than the saturated vapor pressure at the corresponding temperature, so no cavitation will occur, the energy consumption is low, the bubble size distribution is wide, and it is easy to control. Utility Model Content

[0004] In view of the above-mentioned deficiencies, the purpose of the utility model is to provide a micro-nano bubble generating device for flotation separation of fine minerals, which solves the technical problems of difficulty in jetting mixed jets, wide and difficult to control bubble size distribution, easy corrosion and high energy consumption.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A micro-nano bubble generating device suitable for flotation separation of fine minerals, comprising an internal part 1, an external part 2 and a nozzle 3 which are detachably threadedly connected, wherein a gas inlet 11 is provided at the top of the internal part 1, a two-phase mixing cyclone 13 is provided at the bottom, a bubble hydraulic regulator 12 is provided along the circumferential direction of the internal part above the two-phase mixing cyclone 13, the external part 2 is provided with a liquid inlet 21, the lower space formed after the external part 2 and the internal part 1 are connected is a bubbly flow mixing chamber 5, a stainless steel wire mesh 6 is embedded in the bubbly flow mixing chamber 5, and the aspect ratio of the bubbly flow mixing chamber is between 0.5:1 and 1.0:1;

[0007] A bubble generator is also arranged above the two-phase mixing cyclone 13. The bubble hydraulic regulator 12 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 bubble generator is in the shape of an inverted disc, and the inner core of the bottom of the inverted disc is fixed above the two-phase mixing cyclone 13 by a spring. The side of the inverted disc is evenly distributed with circumferential grooves having the same number as the passages of the bubble hydraulic regulator, and the opening width of the circumferential grooves is smaller than the passage diameter of the bubble hydraulic regulator, and the position of the circumferential grooves is opposite to the setting position of the passage of the bubble hydraulic regulator.

[0008] The nozzle comprises a nozzle body and a nozzle, and the nozzle comprises a tapered section 3A and a straight section 3B. The angle between the tapered section 3A and the central axis of the nozzle is 45-60°, and the height of the straight section on the central axis is 1-2 mm.

[0009] Furthermore, 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 evenly distributed in a circle with the central straight line segment as the center, the central straight line segment and the peripheral straight line segments can be parallel to each other or form a certain angle; the number of peripheral straight line segments will affect the flow rate of the liquid suction port and the gas suction port, the upper limit of the jet height is 1m, and the inclination range of the peripheral straight line segments is 0-60°.

[0010] Furthermore, the opening width of the circumferential groove is 0.8-1.2mm, the passage diameter of the bubble hydraulic regulator 12 is 2-3mm, the outer bottom and side of the bubble generator are arc transition arc surfaces; the aperture range of the stainless steel wire mesh is 0.07mm-0.4mm.

[0011] Furthermore, the device includes a variety of internal parts of a bubble hydraulic regulator 12 with different passage diameters; the bubble hydraulic regulator is divided into three categories according to different passage diameters: 1mm, 2mm and 3mm; the nozzle has a variety of specifications: a single-hole nozzle 31, a SA0 multi-porous nozzle 32, a SA45 multi-porous nozzle 33 and a SA60 multi-porous nozzle 34, the single-hole nozzle has only one vertical outlet, the multi-porous nozzle refers to a nozzle with a plurality of outlets inclined at an angle to the axis of the nozzle in addition to the vertical outlet in the center, one end of the plurality of outlets is connected to the reducing section of the nozzle, and the other end is located on the lower end section of the nozzle; SA45 is at a 45° angle to the central axis of the nozzle, SA60 is at a 60° angle to the central axis of the nozzle, and SA0 is at a 0° angle to the central axis of the nozzle.

[0012] Furthermore, the gas flow rate at the gas inlet is 0.06-0.16m 3 / h, the liquid flow rate supplied to the circulating liquid suction port is 2-10kg / h;

[0013] After the high-pressure gas and the circulating liquid are cross-mixed, a two-phase bubbly flow is formed. At this time, the bubble size in the bubbly flow is controlled by the bubble generator 4. When small-sized micro-nano bubbles are needed in the flotation process, the gas mass flow rate is small, the spring is in a static fixed position, and the gas passes through the circumferential groove on the bubble generator 4 and obliquely enters the primary mixing chamber between the internal parts and the external parts above the two-phase mixing cyclone through the passage of the bubble hydraulic regulator. When microbubbles of a full range of sizes are needed in the flotation process, the spring under the bubble generator is in a compressed state by increasing the gas mass flow rate, changing the inclination of the circumferential groove of the bubble generator and the bubble hydraulic regulator, so that the gas can gradually enter the primary mixing chamber directly through the bubble hydraulic regulator 12.

[0014] A 304 stainless steel wire mesh 6 is embedded in the bubbly flow mixing chamber 5. The bubble diameter is adjusted according to the different apertures of the stainless steel wire mesh. As the aperture of the stainless steel wire mesh 6 decreases, the bubble diameter gradually decreases, the proportion of small-scale bubbles first decreases and then increases, the number of small-scale bubbles increases, and the probability of small-scale bubbles coalescing is greater than the probability of breaking.

[0015] Due to the internal and external pressure difference and velocity gradient, the bubbles break into smaller micro-nano bubbles when the bubbly flow passes through the nozzle outlet. The jet boundary layer entrainment effect prolongs the residence time of the micro-nano bubbles from 40 minutes to 1 hour, thereby enhancing the flotation separation efficiency of fine minerals.

[0016] Compared with the prior art, the beneficial effects of the utility model are:

[0017] 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 the size distribution of the micro-nano bubbles is more uniform, suitable for various working conditions, making the bubble size distribution wider, which is beneficial to the flotation separation of minerals.

[0018] 2) By adopting different nozzles 3, the micro-nano bubble jet angle can be adjusted, and the jet cone angle can be increased to 60°, which is suitable for various containers.

[0019] 3) The disturbance of the jet vortex in the two-phase mixing cyclone 13 can enhance the uniformity of the bubbling flow. The 304 stainless steel wire mesh 6 (the pore size of the 304 stainless steel wire mesh is 11 kinds, ranging from 0.07mm to 0.4mm. They are 0.07mm, 0.09mm, 0.11mm, 0.12mm, 0.15mm, 0.16mm, 0.19mm, 0.24mm, 0.27mm, 0.31mm, 0.4mm respectively. The diameter of the micro-nano bubble decreases with the decrease of the pore size, and the distribution of the micro-nano bubble size (bubble diameter is less than 100μm) is the largest at 0.11mm) also has the same effect.

[0020] 4) The utility model is a reverse application of the bubble atomizing nozzle. Compared with other bubble generating devices, the device has low energy consumption, wide application, and is easy to adjust. The nozzle has a simple structure, is easy to replace, is not prone to clogging and cavitation corrosion, and has a longer service life.

[0021] The utility model is suitable for a micro-nano bubble generator for fine mineral flotation separation. It is a micro-nano bubble generator with low energy consumption (reduced power consumption and gas consumption), small flow rate, adjustable jet cone angle and bubble size distribution. The micro-nano bubble generator proposed in the utility model consumes 6.53×10 -4 kW·h, which is 23% and 29% lower than that of the Venturi nozzle and the pressure nozzle, respectively. The jet cone angle is achieved by replacing different nozzles 3. The jet cone angle of the single-hole nozzle 31 is 29°, the jet cone angle of the SA0 porous nozzle 32 is 53°, the jet cone angle of the SA45 porous nozzle 33 is 98°, and the jet cone angle of the SA60 porous nozzle 34 is 135°. The total outlet cross-sectional area of ​​the nozzle is the same, so 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 the smallest, which is 0.76μm. And with the different apertures of the 304 stainless steel wire mesh 6 and the gas-liquid mass flow ratio, the size distribution of the micro-nano bubbles is different.

[0022] The micro-nano bubbles formed by the utility model are uniform and stable, have a simple structure, are easy to repair and replace, have a low working pressure, and are widely applicable, thus solving the problem of small bubble adjustment range of the existing micro-nano bubble generating device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a structural diagram of the assembly of components of a micro-nano bubble generator suitable for flotation separation of fine minerals;

[0024] In the accompanying drawings, there are internal parts 1, external parts 2, nozzles 3, bubble generators 4, bubble flow mixing chambers 5, and 304 stainless steel wire meshes 6.

[0025] Figure 2 This is a diagram of the internal parts structure of a micro-nano bubble generator suitable for flotation separation of fine minerals;

[0026] In the accompanying drawings, there are a gas inlet 11, a bubble hydraulic regulator 12, and a two-phase mixing cyclone 13.

[0027] Figure 3 This is a diagram of the external parts structure of a micro-nano bubble generator suitable for flotation separation of fine minerals;

[0028] In the drawings, a circulating liquid introduction port 21 is provided.

[0029] Figure 4Figure 3 is a structural diagram of different forms of nozzles for a micro-nano bubble generating device suitable for flotation separation of fine minerals, wherein 31 is a single-hole nozzle, 32 is a SA0 porous nozzle, 33 is a SA45 porous nozzle, and 34 is a SA60 porous nozzle. The jet cone angle (the jet range) of the single-hole nozzle 31 is 29°, the jet cone angle of the SA0 porous nozzle 32 is 53°, the jet cone angle of the SA45 porous nozzle 33 is 98°, and the jet cone angle of the SA60 porous nozzle 34 is 135° (two oblique jet formation ranges).

[0030] Figure 5 It is a structural schematic diagram of the bubble hydraulic regulator 12, a is a top view, and b is a main view.

[0031] Figure 6 This is a structural diagram of a bubble generator in a micro-nano bubble generating device suitable for flotation separation of fine minerals;

[0032] In the attached drawings, a is a top view, and b is a main view.

[0033] Figure 7 is the normal distribution diagram of bubble diameter.

[0034] Figure 8 It is a cumulative percentage graph of bubble diameter.

[0035] Fig. 9 Particle size distribution of feed for flotation separation of fine minerals.

[0036] Fig.10 This is a diagram of the flotation separation efficiency of fine minerals. DETAILED DESCRIPTION

[0037] The present invention is further explained below in conjunction with the embodiments and drawings, but this is not intended to limit the scope of protection of the present application.

[0038] The utility model is applicable to the physical and chemical field of fine mineral flotation separation, and can separate useful fine minerals from waste rocks, impurities and other useless minerals. The initial turbulent kinetic energy of the jet is 10m 2 / s 2 .

[0039] The utility model is suitable for a micro-nano bubble generating device for flotation separation of fine minerals (see Figure 1-6 ), which is formed by the internal part 1, the external part 2 and the nozzle 3 being rigidly connected by threads in sequence. The internal part 1 is provided with a gas inlet 11, a bubble hydraulic regulator 12 and a two-phase mixing cyclone 13, and the bubble hydraulic regulator 12 and the two-phase mixing cyclone 13 are processed in an integrated manner. The two-phase mixing cyclone 13 has an inclination angle of 45 degrees, a height of 6 mm, an outlet side length of 2 mm, and is provided with four cyclone grooves on the side surface of the lower part of the internal part.

[0040] The external part 2 is provided with a liquid inlet 21 and a bubbly flow mixing chamber 5. The height difference between the liquid inlet 21 and the bubble hydraulic regulator 12 is 5 mm, and the liquid inlet is located above the bubble hydraulic regulator 12. The gas inlet 11 and the liquid inlet 21 are both connected with threaded quick-connect joints to connect with the gas pipeline and the liquid pipeline. The bubbly flow mixing chamber 5 is the space formed between the external part 2 and the internal part 1 after being connected. The aspect ratio of the bubbly flow mixing chamber is between 0.5:1 and 1.0:1. A 304 stainless steel wire mesh 6 is embedded in the bubbly flow mixing chamber 5 for cutting large-scale bubbles, and at the same time, the bubbles are evenly distributed in the bubbly flow mixing chamber, so as to achieve the purpose of adjusting the size and distribution of bubbles.

[0041] A bubble generator 4 is also provided in the gas introduction channel of the internal parts above the two-phase mixing cyclone 13, and the bubble generator is in the shape of an inverted disk (see Figure 6 ), the inner core of the bottom of the inverted disk is fixed above the two-phase mixing cyclone 13 by a spring, and circumferential grooves with the same number as the passage of the bubble hydraulic regulator are evenly distributed on the side of the inverted disk, the opening width of the circumferential grooves is smaller than the passage diameter of the bubble hydraulic regulator, and the position of the circumferential grooves is opposite to the setting position of the passage of the bubble hydraulic regulator.

[0042] There are four main types of nozzles: single-hole nozzle 31, SA0 multi-hole nozzle 32, SA45 multi-hole nozzle 33 (45°) and SA60 (indicates that the angle between the oblique line and the vertical axis is 60°) multi-hole nozzle 34. The nozzles are detachable and can be selected according to needs. The nozzle includes a nozzle body and a nozzle, and the nozzle includes a reduction section 3A and a straight section 3B. Figure 4The space from the straight line segment upward to the 304 stainless steel wire mesh 6 is the reduction segment 3A. The angle between the reduction segment 3A and the horizontal plane is 30°, and the height is 5mm. When the diameter of the bottom of the wire mesh increases, the height of the reduction segment is low, and the bubbles will hit the wall, which will increase the size of the bubbles. 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, and the peripheral straight line segments are evenly distributed in a circle with the central straight line segment as the center. A total of 5 outlet holes are set on the circumference (such as SA45 porous nozzle 33 and SA60 porous nozzle 34). In the figure, the central straight line segment and the peripheral straight line segment of the SA0 porous nozzle 32 are parallel to each other, and the angle between them and the horizontal plane is 90°. The number of peripheral straight line segments will affect the increase in the flow rate of the liquid suction port and the gas suction port. The upper limit of the jet height is 1m. The larger the inclination range of the peripheral straight line segment, the larger the jet angle and the wider the jet range. The jet range is adjusted by adjusting the inclination angle of the peripheral straight line segment. The height of the middle straight line segment is 1-2mm. The single-hole nozzle 31 in the figure is a single straight line segment, with a gas flow rate of 0.163 / h, a liquid flow rate of 10kg / h, and a minimum jet height of 50mm. Different nozzles present different jet cone angles, and the cone angle can be adjusted by replacing different nozzles 3.

[0043] In this embodiment, the opening width of the circumferential groove is about 1 mm, the opening diameter of the bubble hydraulic regulator 12 is about 2 mm, and the bubble generator is in the shape of an inverted disk, with the outer bottom and side surfaces forming arc transition surfaces to reduce flow resistance.

[0044] The bubble generator is made of corrosion-resistant metal or alloy material, and the elastic modulus of the spring is 93E / GPa.

[0045] The utility model proposes a micro-nano bubble generating device suitable for flotation separation of fine minerals based on the bubble atomization mechanism and turbulent jet theory. After the high-pressure gas and the circulating liquid are cross-mixed, a two-phase bubbly flow is formed, and the bubble size in the bubbly flow is controlled by the bubble generator 4. When small-sized micro-nano bubbles are needed in the flotation process, the gas mass flow rate is small, the spring is in a static fixed position, and the gas enters the primary mixing chamber (the cavity between the internal parts and the external parts above the two-phase mixing cyclone) through the circumferential groove on the bubble generator 4 and obliquely through the passage of the bubble hydraulic regulator. When microbubbles of a full size range (both micro-nano bubbles and large bubbles) are needed in the flotation process, the spring under the bubble generator is in a compressed state by increasing the gas mass flow rate, and the inclination degree of the circumferential groove of the bubble generator and the bubble hydraulic regulator is changed, so that the gas can gradually enter the primary mixing chamber directly through the bubble hydraulic regulator 12.

[0046] In addition, the micro-nano bubbles can also be controlled by the bubble hydraulic regulator 12. The bubble hydraulic regulator 12 is divided into three types: 1mm, 2mm and 3mm according to the different passage diameters. The diameter of the micro-nano bubbles finally generated decreases as the diameter of the bubble hydraulic regulator decreases. After the two-phase bubbly flow passes through the two-phase mixing cyclone 13, a rotating shear turbulence is generated under the action of centrifugal force, and the bubbles begin to tear faster to form a centrifugal bubbly flow.

[0047] The 304 stainless steel wire mesh 6 is embedded in the bubbly flow mixing chamber 5, which reduces the bubble size and promotes the uniform distribution of the bubbly flow. The 304 stainless steel wire mesh 6 mainly adjusts the bubble diameter according to its different apertures. As the aperture of the 304 stainless steel wire mesh 6 decreases, the bubble diameter gradually decreases, and the proportion of small-scale bubbles first decreases and then increases. The main reason is that the number of small-scale bubbles increases, and the probability of aggregation of small-scale bubbles is greater than the probability of breakage. There are 11 apertures of the 304 stainless steel wire mesh, ranging from 0.07mm to 0.4mm. When the bubble hydraulic regulator is of 1mm type and the aperture of the 304 stainless steel wire mesh is 0.11mm, the proportion of small-scale bubbles (the diameter of the generated micro-nano bubbles is ≤100μm) can reach a maximum of 96%. The centrifugal bubbly flow passes through the 304 stainless steel wire mesh 6 to form a discrete bubbly flow by shearing the flow. Due to the effect of the internal and external pressure difference and the velocity gradient, the bubbles break into smaller micro-nano bubbles when the bubbly flow passes through the nozzle outlet. The nozzle is easy to disassemble and replace, and the uniform distribution of micro-nano bubbles can be achieved by replacing nozzles of different forms. The entrainment effect of the jet boundary layer (within 5 cm downstream of the nozzle) causes the residence time of micro-nano bubbles to be extended from 40 min to 1 h, thereby enhancing the flotation separation efficiency of fine minerals.

[0048] The gas inlet and liquid inlet threaded quick-connect joints are sealed with O-type rubber rings. The nozzle is rigidly connected to the external parts by thread. The internal parts are rigidly connected to the external parts by thread. O-type rubber rings are placed at all threaded connections to prevent gas and liquid leakage.

[0049] The fluid working pressure of the gas inlet and liquid inlet is 0.1-0.6MPa (the existing one can only form bubbles but not jets at 0.1MPa). Compared with the flotation separation of the same fine minerals reaching 95% (comparison between the existing jet and bubble separation device and the integrated device), the required pressure is smaller and the effect is better. The gas flow rate supplied to the gas inlet is 0.06-0.16m 3 / h, the required gas volume is significantly smaller than that of the existing flotation separation device. The liquid flow rate supplied to the circulating liquid suction port is 2-10kg / h. In this embodiment, both air and water are given pressure, and bubbles are formed in the swirl tank, which has a better effect than the existing separation device that only gives air pressure. Because the present application performs mixing in the bubble mixing chamber 5, the pressure difference is increased, which helps to form a jet. Bubbles have been formed at the nozzle of the mixing chamber, and the bubble size is further reduced by the screen, thereby forming an effective jet.

[0050] Implementation method: high-pressure air enters the gas inlet 11 through the gas pipeline, and the liquid enters the liquid inlet 21 through the liquid pipeline. The high-pressure gas (enters the inner channel of the internal parts from the gas inlet) and the liquid (enters from the liquid inlet and enters the bubble generator 4 through the bubble hydraulic regulator 12) are cross-mixed in the bubble generator 4 to form bubbles, and the bubble size can be controlled by the bubble hydraulic regulator 12. Subsequently, the bubbles pass through the two-phase mixing cyclone 13 tangentially into the bubble flow mixing chamber 5. The two-phase mixed fluid undergoes rotational shear turbulent motion, which enhances the turbulent shear force and reduces the size of the bubbles. The bubbles rotate along the wall of the bubble flow mixing chamber 5 (the inner wall of the outer shell 2) due to the centrifugal effect.

[0051] Figure 7 is the normal distribution diagram of bubble diameter under different aspect ratios and Figure 8 The cumulative percentage of bubble diameters is shown in the figure. It can be seen from the figure that bubbles of 0-200 μm can be generated, the bubble distribution is wider, and there are more bubbles of 0-20 μm, which is beneficial to mineral selection. When the aspect ratio of the bubbly flow mixing chamber 5 is 0.5:1, the turbulent shear force acts on the bubbles for a short time, and the probability of bubble breakage is limited, resulting in a small proportion of small bubbles generated by the jet, and bubbles with a diameter less than 70 μm account for 86% (see Figure 8 ), the flotation efficiency of fine minerals is 72% ( Fig.10 See working condition 1, Fig. 9 The size distribution of solid particles in medium condition 1 is mainly 50μm), which is 20% higher than that of the Venturi nozzle jet. As the aspect ratio of the bubbly flow mixing chamber 5 increases, the probability of bubble breakage increases. When the aspect ratio increases to 0.9:1, 94% of the bubbles are smaller than 50μm, and the flotation efficiency of fine minerals is about 82% (see Fig.10 Medium working condition 1 corresponds to the case of length-to-diameter ratio of 0.9), which is 46.5% higher than that of the Venturi nozzle jet. When the length-to-diameter ratio of the bubbly flow mixing chamber 5 continues to increase, some broken small bubbles merge into larger bubbles. When the length-to-diameter ratio increases to 1.0:1, the proportion of bubbles smaller than 50μm drops to 91%, and the flotation efficiency of fine minerals is 79%, which is 40.2% higher than that of the Venturi nozzle jet.

[0052] In order to promote the uniform distribution of the bubbly flow, a 304 stainless steel wire mesh is embedded in the bubbly flow mixing chamber 5. The 304 stainless steel wire mesh further cuts the bubbles in the bubbly flow into smaller bubbles to form a discrete bubbly flow. The discrete bubbly flow is accelerated by the tapering section of the nozzle 3. Due to the large pressure gradient at the nozzle, the bubbles expand and break into microbubbles, and the discrete bubbly flow forms a microbubble jet. The velocity gradient discontinuity between the microbubble jet and the surrounding static fluid produces a vortex, which draws the surrounding fluid into the jet boundary layer (enters the jet boundary layer from the outside of the jet boundary layer), so that the microbubbles are constantly moving, deforming, and breaking in the external liquid system to produce micro-nano bubbles. At the same time, due to the effect of the jet boundary layer entrainment, the micro-nano bubbles can form back mixing, extend the residence time of the micro-nano bubbles, and enhance the flotation separation efficiency of fine minerals.

[0053] 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 the jet are injected into the turbid liquid and come into contact with the surface of the target mineral particles. The adsorption of micro-nano bubbles on the surface of the mineral particles will lead to the interaction between the bubbles and the minerals. This interaction is achieved through hydrophobic interaction or electrochemical action, which prompts the bubbles and mineral particles to form bubble-mineral complexes. Due to the buoyancy of the bubbles, the bubble-mineral complex is brought to the surface of the turbid liquid by the micro-nano bubbles to form scum. In this way, the target mineral is separated from the waste rock and other impurities, and the purpose of flotation separation is achieved. Compared with ordinary micro-nano gas flotation, the micro-nano bubbles generated by the device have higher adsorption capacity and faster flotation speed (each bubble is more widely distributed and generated by jet convolution), so less flotation agent can be used in the flotation process, reducing the use of chemical reagents and reducing production costs. And compared with traditional bubble generation devices, the energy consumption is lower, and the energy utilization efficiency is improved. The micro-nano bubbles generated by the jet are usually formed by the diffusion of gas microbubbles in the high-speed liquid flow in the liquid. The high-speed jet provides enough power to generate turbulence in the liquid, increasing the mixing degree of the liquid, so that the micro-nano bubbles are evenly dispersed in the liquid.

[0054] The utility model device firstly adjusts the mass flow ratio of gas and liquid and uses a bubble generator to control the gas content and bubble concentration in the mixture. Then, the size of the generated bubbles is adjusted by adjusting the structural parameters of the device (the length-to-diameter ratio of the mixing chamber and the number of nozzle outlets) and the size of the mixing area. Figure 7 and Figure 8 They are the effects of aspect ratio on the normal distribution and cumulative percentage of bubble diameters ejected from bubble atomizing nozzles in water, Fig.10This is the flotation separation efficiency curve of fine minerals. The results show that for a smaller particle size distribution (such as the size distribution of solid particles in condition 1 is mainly 50μm), the flotation separation efficiency is highest when the aspect ratio is 0.9. For flotation processes with smaller particle sizes but larger distribution (such as the size distribution of solid particles in conditions 2 and 3 is mainly 56μm and 100μm), the flotation separation efficiency increases significantly. When 90% of the particles are less than 150 microns in size and have a larger distribution (the size distribution of solid particles in condition 4 is mainly 158μm), the flotation separation efficiency of this device can reach 96%.

[0055] Anything not described in the present invention is applicable to the prior art.

Claims

1. A micro-nano bubble generating device suitable for flotation separation of fine minerals, comprising an internal part, an external part and a nozzle which are detachably threadedly connected, a gas inlet is provided on the top of the internal part, a two-phase mixing cyclone is provided at the bottom, a bubble hydraulic regulator is provided along the circumferential direction of the internal part above the two-phase mixing cyclone, a liquid inlet is provided on the external part, and the lower space formed after the external part and the internal part are connected is a bubble flow mixing chamber, a stainless steel wire mesh is embedded in the bubble flow mixing chamber, and the characteristics are: The aspect ratio of the bubbly 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 bubble generator is in the shape of an inverted disc, and the inner core of the bottom of the inverted disc is fixed above the two-phase mixing cyclone by a spring, and circumferential grooves with the same number as the passages of the bubble hydraulic regulator are evenly distributed on the side of the inverted disc, and the opening width of the circumferential grooves is smaller than the passage diameter of the bubble hydraulic regulator, and the position of the circumferential grooves is opposite to the setting position of the passage of the bubble hydraulic regulator.

2. The micro-nano bubble generating device according to claim 1, characterized in that: The nozzle comprises a nozzle body and a nozzle, and the nozzle comprises a reduced section and a straight section; The straight line segments include a central straight line segment and a peripheral straight line segment. The central straight line segment is located on the axis, and the peripheral straight line segments are evenly distributed in a circle 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 angle. The upper limit of the jet height is 1m, and the inclination range of the peripheral straight line segment is 0-60°.

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

4. The micro-nano bubble generating device according to claim 1, characterized in that: The device includes a variety of internal parts of a bubble hydraulic regulator with different passage diameters; the bubble hydraulic regulator is divided into three categories according to different passage diameters: 1mm, 2mm and 3mm; the nozzle has a variety of specifications: a single-hole nozzle, a SA0 multi-hole nozzle, a SA45 multi-hole nozzle or a SA60 multi-hole nozzle, the single-hole nozzle has only one vertical outlet, the multi-hole nozzle refers to a nozzle with a plurality of outlets inclined at an angle to the axis of the nozzle in addition to the vertical outlet in the center, one end of the plurality of outlets is connected to the reducing section of the nozzle, and the other end is located on the lower end section of the nozzle; SA45 is at a 45° angle to the central axis of the nozzle, SA60 is at a 60° angle to the central axis of the nozzle, and SA0 is at a 0° angle to the central axis of the nozzle.

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