Microbubble dispersion strengthening multiphase reaction leaching tank

Abstract

The microbubble dispersion strengthening multiphase reaction leaching tank comprises a tank body connected with an ore feeding pipe, a stirring device is arranged in the tank body, and a micro-nano bubble generating device and an inflation pipe are connected into the tank body; an outlet of the micro-nano bubble generating device is located in the middle-lower area in the tank body, and micro-nano bubbles are supplied into the tank body; an outlet of the inflation pipe is located in the lower area in the tank body, and air supply of the tank body is achieved. According to the micro-nano bubble generating device, micro-nano bubbles separated out have the advantage of being high in gas dissolving speed, steady flow can be reduced, the diffusion effect can be improved, when the stirring device rotates rapidly, a vortex is formed, the micro-nano bubbles are sucked into the vortex, the oxygen content in ore pulp reaches a supersaturated state, upward circulation is achieved, uniform suspension mixed liquid is formed, and the stirring effect is improved. Therefore, the method is particularly suitable for treating the micro-fine particle low-grade minerals.

Description

Technical Field

[0001] The utility model belongs to the technical field of mineral leaching, in particular to a microbubble dispersion enhanced multiphase reaction leaching tank. Background Art

[0002] Leaching tanks are essential equipment in non-ferrous metal extraction and metallurgy. Currently, mineral leaching operations mostly utilize mechanically aerated leaching devices. Aeration agitates and circulates the slurry, while also providing oxygen for mineral dissolution. Currently available leaching tanks primarily include mechanically agitated tanks, air-agitated tanks, mixed air and mechanical agitation tanks, and pneumatic agitation tanks. While these tanks have been successfully applied in mineral processing, they still have drawbacks and limitations.

[0003] The main disadvantages of traditional mechanical agitators are: (1) high speed requirements and high energy consumption; (2) the need for an impeller cover to form a negative pressure to inhale the gas; (3) the equipment is subject to severe wear and tear, and there are mechanical moving parts inside, which makes operation inconvenient and requires a lot of maintenance work.

[0004] The main disadvantages of traditional air agitation tanks are: (1) high investment costs; (2) large plant area and high plant height; (3) the need for a large air compressor, high drive motor power, high power consumption, and high production costs; (4) large aeration air volume, which easily generates a large number of bubbles and causes tank overflow, especially when the material being processed is flotation concentrate.

[0005] The main disadvantages of the traditional pneumatic agitator are: (1) the dissolved oxygen content in the slurry is relatively low; (2) the foaming method has disadvantages; (3) the "settling tank" phenomenon still exists, and the leaching tank is difficult to clean after "settling tank". Summary of the Invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a microbubble dispersion enhanced multiphase reaction leaching tank, so as to reduce the footprint, reduce equipment investment, use and maintenance costs, while accelerating mineral dissolution, increasing the leaching rate and shortening the leaching time.

[0007] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0008] The microbubble dispersion enhanced multiphase reaction leaching tank comprises a tank body connected to a feed pipe, a stirring device is provided in the tank body, and a micro-nano bubble generating device and an aeration pipe are connected to the tank body;

[0009] The outlet of the micro-nano bubble generating device is located in the middle and lower area of ​​the tank body, supplying micro-nano bubbles into the tank body; the outlet of the inflation pipe is located in the lower area of ​​the tank body, realizing air supply to the tank body.

[0010] In one embodiment, the feed pipe is inclined at an angle of 60 degrees to the inner wall of the tank body, and its height is at the upper middle position of the tank body.

[0011] In one embodiment, the stirring device includes a stirring shaft and a double impeller, wherein the upper impeller of the double impeller is located in the upper area of ​​the tank body, and the lower impeller is located in the lower area of ​​the tank body.

[0012] In one embodiment, the height of the micro-nano bubble generating device is located in the middle of the upper impeller and the lower impeller of the double impeller.

[0013] In one embodiment, the interior of the tank body is a cylindrical space, and the distance between the outlet of the micro-nano bubble generating device and the plane center of the tank body is one-quarter of the tank body diameter.

[0014] In one embodiment, the micro-nano bubble generating device is equipped with a one-way valve to prevent the slurry from flowing back when the air pressure changes.

[0015] In one embodiment, the interior of the trough body is a cylindrical space, and the inner wall of the trough body has four vertical plates evenly distributed along the axial direction, and each vertical plate is arranged radially; there are four micro-nano bubble generating devices, which are evenly distributed along the circumferential direction; there are four inflation tubes, which are evenly distributed along the circumferential direction.

[0016] In one embodiment, the inflation tube is L-shaped, with the outlet end facing the plane center of the tank body.

[0017] In one embodiment, the vertical tube of the inflation tube is 300 mm away from the inner wall of the tank body, the horizontal tube is 300-500 mm away from the bottom of the tank, the vertical plate is 300-500 mm away from the top and bottom of the tank, and the distance from the bottom of the tank is smaller than the distance from the horizontal tube of the inflation tube to the bottom of the tank.

[0018] In one embodiment, the micro-nano bubble generating device includes a generating tube, the head end of the generating tube is a tapered port, a microporous medium is provided at the end of the tapered port, an oblique air inlet is provided at the tail end of the generating tube, and the one-way valve is provided inside the generating tube.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. The utility model microbubble dispersion enhanced multiphase reaction leaching tank is installed with a micro-nano bubble generator in the tank. The micro-nano bubbles precipitated by the micro-nano bubble generator have the characteristics of fast gas dissolution rate, which can reduce steady flow and improve the diffusion effect. When the stirring device rotates rapidly, a vortex is formed. The micro-nano bubbles are sucked into the vortex, causing the oxygen content in the slurry to reach a supersaturated state and circulate upward to form a uniform suspended mixed liquid, thereby quickly leaching fine-grained low-grade minerals. Therefore, it is particularly suitable for treating fine-grained low-grade minerals.

[0021] 2. The utility model utilizes double impellers to fully stir, so that the slurry and micro-nano bubbles are evenly mixed, which increases the contact probability between the micro-nano bubbles and the slurry, is conducive to accelerating the dissolution of minerals, improving the leaching rate, and shortening the leaching time.

[0022] 3. The utility model is provided with an upper one-way valve on the micro-nano bubble generating device to prevent the slurry from flowing back when the air pressure changes.

[0023] 4. The utility model only occupies land for the tank body, which occupies less area than the traditional mechanical mixing tank.

[0024] 5. The micro-nano bubble generator of this utility model has a small and precise structure. The micro-nano bubbles generated are uniform in size, large in number, and exist for a long time, which increases the contact opportunity with the bubbles and can fully contact with the slurry, thereby increasing the diffusion degree of the bubbles and effectively improving the mass transfer efficiency at the gas-liquid interface.

[0025] 6. The utility model is provided with four inflation pipes, which meets the equipment structure of providing circulation power and is easy to prevent corrosion. At the same time, compared with other equipment, it improves the inflation and stirring capabilities, increases the degree of slurry circulation, reduces sand settling at the bottom of the tank, prevents the occurrence of tank settling, and reduces equipment maintenance costs.

[0026] 7. The utility model has small micro-nano bubbles and produces finer bubbles, which increases the surface area of ​​the bubbles, improves the leaching rate, shortens the leaching time, and can reduce the amount of leaching agents used. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram (perspective view) of the utility model.

[0028] Figure 2 It is a structural schematic diagram (axonometric diagram) of the utility model.

[0029] Figure 3 It is a schematic structural diagram (top view) of the utility model.

[0030] Figure 4 It is a structural schematic diagram of the micro-nano bubble generating device of the utility model. DETAILED DESCRIPTION

[0031] The following describes the implementation of the present invention in detail with reference to the accompanying drawings and examples.

[0032] like Figure 1 、 Figure 2 and Figure 3 As shown, the utility model is a microbubble dispersion enhanced multiphase reaction leaching tank, comprising a tank body 1, a stirring device is provided inside the tank body 1, and is connected to a ore feeding pipe 2, an air filling pipe 4 and a micro-nano bubble generating device 6.

[0033] Among them, the ore feeding pipe 2 is used to feed ore slurry into the trough, the inflation pipe 4 is used to supply air to the trough body 1, and its outlet is located in the lower area of ​​the trough body 1. The micro-nano bubble generating device 6 is a key part of the utility model, which is used to supply micro-nano bubbles into the trough body 1, and its outlet is located in the middle and lower area of ​​the trough body 1.

[0034] According to the above structure, the slurry is fed into the tank body 1 through the ore feeding pipe 2. Under the action of gravity, the slurry moves downward to the bottom of the tank body 1. The air filling pipe 4 starts to supply air, and at the same time, the compressed air enters the micro-nano bubble generating device 6, spraying micro-nano bubbles to diffuse into the slurry. The stirring device stirs, and the slurry forms a vortex when it rotates rapidly. At this time, the micro-nano bubbles are sucked into the vortex, so that the oxygen content in the slurry reaches a supersaturated level and circulates upward to form a uniform suspended mixture. The micro-nano bubble generating device can promote the generation of micro-nano bubbles. The micro-nano bubbles greatly increase the probability and reaction time of contact between the slurry and the air, making the bubbles more uniform, and ultimately shortening the leaching time and increasing the leaching rate.

[0035] Furthermore, in the leaching tank, the feed pipe 2 is often inclined at a 60-degree angle to the tank body 1 and is at an upper middle position of the tank body 1, typically slightly above half the height, to ensure smooth inflow of the slurry.

[0036] Furthermore, the stirring device of the present invention includes a stirring shaft 8 and a dual impeller 3. The so-called dual impeller 3 refers to a structure having two impellers along the axial direction of the stirring shaft 8. In this embodiment, they are named as upper impellers and lower impellers according to their height orientation. The upper impeller is located in the upper area of ​​the tank body 1, and the lower impeller is located in the lower area of ​​the tank body 1. The upper area and the lower area are both based on the height center position of the tank body 1. The structure of the dual impeller 3 can make the mixing of the slurry and the micro-nano bubbles more uniform. In particular, when the height of the micro-nano bubble generating device 6 is set at the middle position of the upper impeller and the lower impeller of the dual impeller 3.

[0037] Furthermore, the interior of the tank body 1 is a cylindrical space, which is the current mainstream tank body space and is convenient for stirring and maintenance.

[0038] There are four aeration tubes 4, evenly spaced along the circumference. These are L-shaped, consisting of a vertical and horizontal tube. The top of the vertical tube serves as the inlet, while the free-standing end of the horizontal tube serves as the outlet, facing the center of the tank body 1. The vertical tubes are approximately 300 mm from the inner wall of the tank body 1, while the horizontal tubes are 300-500 mm from the bottom. This ensures air supply to the tank body 1, enhancing aeration and stirring capabilities.

[0039] Four vertical plates 5 are evenly distributed along the inner wall of the trough body 1 along the axial direction, and each vertical plate 5 is arranged radially. The vertical plates 5 are 300-500 mm away from the top and bottom of the trough. The distance from the vertical plates 5 to the bottom of the trough is smaller than the distance from the horizontal tube of the inflation tube 4 to the bottom of the trough. That is, the bottom insertion depth is deeper than the inflation tube. The vertical plates 5 can ensure the smooth movement of the ore flow.

[0040] There are also four micro-nano bubble generating devices 6, evenly distributed along the circumference. The distance between the outlet of each micro-nano bubble generating device 6 and the center of the plane of the tank body 1 is one-quarter of the tank body diameter. This ensures that the generated micro-nano bubbles are more evenly mixed with the slurry stirred by the dual impellers 3. The micro-nano bubbles fully contact the slurry, increasing the chance of collision with the slurry, increasing the dispersion of the bubbles, making them more uniform, and improving the leaching rate.

[0041] Furthermore, a one-way valve 7 is installed on the micro-nano bubble generating device 6, and the one-way valve 7 can prevent the slurry from flowing back when the air pressure changes.

[0042] The theoretical basis of this utility model is as follows:

[0043] Micro-nano bubbles are special bubbles that exist at the gas-liquid interface and have a diameter ranging from fifty microns to tens of nanometers.

[0044] Characteristics of micro-nano bubbles: (1) Small bubble size, high probability of collision with minerals; (2) Large specific surface area, high surface energy, and high selectivity; (3) Strong bubble stability, slow rising and falling speed, which can reduce the sedimentation rate of minerals; (4) High gas solubility rate, automatic pressurized dissolution; (5) Can produce a large number of free radicals, high gas-liquid mass transfer efficiency; (6) High interfacial potential, good flotation effect.

[0045] Micro-nano bubbles stay in water for a long time, have large specific surface area, high surface energy, high selectivity, strong stability, slow rising and falling speed, fast gas dissolution speed, high gas-liquid mass transfer efficiency, and high dissolution rate. They can better process low-grade fine-grained minerals, have good working effects and high leaching rates.

[0046] Leaching is a multiphase chemical reaction occurring at the interface of solid, liquid, and gas. The reaction process can be divided into: convective diffusion of oxygen dissolved in water and leaching agents toward the mineral surface; adsorption of oxygen on the mineral surface by the agent; chemical reaction between the adsorbed leaching agent and oxygen and the mineral, dissolving the useful components in the solid mineral; desorption of the dissolved useful mineral from the solid surface; and diffusion of the desorbed substances into the solution. The oxygen concentration and diffusion rate during the leaching process are crucial factors affecting the leaching effect. For example, in cyanide leaching of gold, oxygen in the solution diffuses and reacts with CN- to the gold ore surface, generating Au(CN)2- ions, which enter the solution and are ultimately recovered. The reaction is shown in Equation (1).

[0047] 2Au+4CN-+O2+2H2O=2Au(CN)2-+2OH - +H2O2 (1)

[0048] Microinterface reaction enhancement is mainly achieved through interfacial mass transfer enhancement. Replacing the milli-centimeter-scale macro-interface of traditional reactors with a microinterface can increase the mass transfer interface area by several times or even dozens of times. Even if the mass transfer coefficient is the same, the mass transfer rate will increase proportionally. Interface enhancement has always been one of the basic principles of multiphase system reaction enhancement. The reduction of bubbles and droplets from the milli-centimeter scale to the micrometer scale or even the sub-micrometer scale will be the basis for microinterface reaction enhancement. "Microinterface Enhanced Reaction Technology" mainly utilizes the micron-scale high-energy gas and liquid vortex energy conversion principle to efficiently control the geometric scale of gas-liquid and gas-liquid-solid interfaces from the milli-centimeter scale to the micrometer scale, greatly improving the mass-energy transfer efficiency by orders of magnitude.

[0049] The principle of the micro-nano bubble generator 6 of the present invention is to force air to dissolve in water by applying pressure, forming a supersaturated state. The gas is then released through instantaneous decompression, generating a large number of micro-nano bubbles that are ejected from the outlet and dispersed in the slurry. A mixture of slurry and bubbles is formed within the tank. The specific gravity of this mixture is reduced by the incorporation of air. The greater the amount of bubbles, the lighter the specific gravity of the mixture, thereby causing the slurry to rise and achieve circulation. After being ejected from the micro-nano bubble generator, the formed micro-nano bubbles continue to advance for a distance in the external flow field before turning back and gradually filling the entire flow field area.

[0050] When performing transient simulations on the micro-nano bubble generator, three sections facing outward were set in the external flow field to collect bubbles passing through the sections. The diameter range of the bubble group and the corresponding bubble number distribution were counted. The number distribution of micro-nano bubbles of different diameters collected at the three sections is shown in Table 1.

[0051] Table 1 Bubble diameter distribution diagram collected at different sections

[0052]

[0053] As can be seen from Table 1, the diameter of the bubbles produced by the micro-nano bubble generator 6 is generally distributed around 30 μm, with good uniformity in the particle size distribution range. As the inlet pressure of the micro-nano bubble generator 6 increases, the number of micro-nano bubbles produced increases first and then decreases, reaching a peak at an inlet pressure of around 1.5 MPa. Therefore, in practical applications, the inlet pressure of the micro-nano bubble generator should be constantly controlled at 1.5-2 MPa before operation to ensure uniform and continuous bubble production, which places high demands on the sealing performance of the equipment.

[0054] In summary, by introducing micro-nano bubbles, firstly, the "nanobubble bridge capillary force" between mineral particles can be used to enhance the agglomeration process of fine-grained minerals; secondly, nanobubbles can be used to enhance the collision and adhesion process between mineral particles and bubbles, so that the minerals and bubbles are in full and stable contact, promoting the interaction between particles-particles and particles-bubbles; thirdly, the slurry and bubbles are evenly mixed, and the bubbles are dispersed in the entire leaching system, which is equivalent to enhancing the stirring while ensuring a higher oxygen concentration, thereby improving the overall leaching rate and leaching effect of the mineral.

[0055] In terms of the specific implementation of micro-nano bubbles, the following technologies are currently available:

[0056] (1) Ultrasonic waves generate micro-nano bubbles. This is mainly based on the cavitation principle of ultrasonic waves;

[0057] (2) Chemical reaction produces micro-nano bubbles. Micro-nano bubbles are produced by chemical reactions using chemical substances;

[0058] (3) Electrolysis. Electrolysis of water by electrodes produces hydrogen and oxygen to obtain micro-nano bubbles;

[0059] (4) Dissolution and degassing method. This method mainly involves pressurizing the air to dissolve it in the water, and then decompressing the air to release it from the water, generating a large number of micro-nano bubbles.

[0060] (5) Air decomposition method. It mainly uses high-speed shearing and stirring to repeatedly shear and break the air, and then mixes it in the water to stably produce a large number of micro-nano bubbles.

[0061] The micro-nano bubble generating device 6 of the present invention adopts the air decomposition method and is an air direct bubble generating device. Figure 4 As shown, it includes a generating tube 61, the tail end of the generating tube 61 is closed, the head end is a tapered mouth, and a microporous medium 62 is provided at the end of the tapered mouth. The microporous medium 62 can be a ceramic microporous material or a metal microporous material, with a micropore diameter of 0.1-3μm and a porosity of not less than 40%. The microporous medium 62 and the one-way valve 7 are used to adjust the pressure air flow. The utility model can adjust the size of the bubbles generated according to the size of the tank body 1.

[0062] There is an air inlet 63 at the tail end of the generating tube 61, and the air inlet 63 is realized by an inclined tube, and compressed air is obliquely input into the generating tube 61. The compressed air can be realized by a compressor or a pump outside the device. The compressed air flows from the tail end to the head end in the tube, and the pressure is further increased after reaching the tapered mouth position. Finally, under the action of pressure, the air is sheared and broken by the microporous medium 62 to obtain a large number of micro-nano bubbles, which are dispersed and input into the interior of the tank body 1.

[0063] The outer wall of the generating tube 61 is provided with a mounting flange 64. After a hole is opened in the side wall of the tank body 1, the generating tube 61 is inserted into the tank body 1 and fastened with the mounting flange 64. Obviously, its head end is inside the tank, while the tail end with the air inlet 63 is outside the tank.

[0064] The one-way valve 7 is installed inside the generating tube 61. After the compressed air enters the generating tube 61 through the air inlet 63, the one-way valve 7 allows the compressed air to flow in one direction, preventing the slurry from flowing back and ensuring the safety and efficiency of the system.

Claims

1. A microbubble dispersion enhanced multiphase reaction leaching tank, comprising a tank body (1) connected to a feed pipe (2), wherein a stirring device is provided in the tank body (1), characterized in that: The tank body (1) is connected to a micro-nano bubble generating device (6) and an inflation tube (4); The outlet of the micro-nano bubble generating device (6) is located in the middle and lower area of ​​the tank body (1), supplying micro-nano bubbles into the tank body (1); the outlet of the inflation tube (4) is located in the lower area of ​​the tank body (1), realizing air supply to the tank body (1).

2. The microbubble dispersion enhanced multiphase reaction leaching tank according to claim 1, characterized in that: The feed pipe (2) forms an inclination angle of 60 degrees with the inner wall of the tank body (1), and its height is at the upper middle position of the tank body (1).

3. The microbubble dispersion enhanced multiphase reaction leaching tank according to claim 1, characterized in that: The stirring device comprises a stirring shaft (8) and a double impeller (3), wherein the upper impeller of the double impeller (3) is located in the upper area of ​​the tank body (1), and the lower impeller is located in the lower area of ​​the tank body (1).

4. The microbubble dispersion enhanced multiphase reaction leaching tank according to claim 3, characterized in that: The height of the micro-nano bubble generating device (6) is located in the middle of the upper impeller and the lower impeller of the double impeller (3).

5. The microbubble dispersion enhanced multiphase reaction leaching tank according to claim 4, characterized in that: The interior of the tank body (1) is a cylindrical space, and the distance between the outlet of the micro-nano bubble generating device (6) and the plane center of the tank body (1) is one-quarter of the tank body diameter.

6. The microbubble dispersion enhanced multiphase reaction leaching tank according to any one of claims 1 to 5, characterized in that: The micro-nano bubble generating device (6) is provided with a one-way valve (7) to prevent the pulp from flowing back when the air pressure changes.

7. The microbubble dispersion enhanced multiphase reaction leaching tank according to claim 6, characterized in that: The micro-nano bubble generating device (6) comprises a generating tube (61), the head end of the generating tube (61) is a tapered opening, a microporous medium (62) is provided at the end of the tapered opening, an oblique air inlet (63) is provided at the tail end of the generating tube (61), and the one-way valve (7) is provided inside the generating tube (61).

8. The microbubble dispersion enhanced multiphase reaction leaching tank according to claim 1, characterized in that: The interior of the tank body (1) is a cylindrical space, and the inner wall of the tank body (1) is evenly distributed with four vertical plates (5) along the axial direction, and each vertical plate (5) is arranged along the radial direction; the number of the micro-nano bubble generating devices (6) is four and evenly distributed along the circumferential direction; the number of the inflation tubes (4) is four and evenly distributed along the circumferential direction.

9. The microbubble dispersion enhanced multiphase reaction leaching tank according to claim 8, characterized in that: The inflation tube (4) is L-shaped, with the outlet end facing the plane center of the tank body (1).

10. The microbubble dispersion enhanced multiphase reaction leaching tank according to claim 9, characterized in that: The vertical tube of the inflation tube (4) is 300 mm away from the inner wall of the tank body (1), and the horizontal tube is 300-500 mm away from the tank bottom. The vertical plate (5) is 300-500 mm away from both the tank top and the tank bottom, and the distance from the vertical plate (5) to the tank bottom is smaller than the distance from the horizontal tube of the inflation tube (4) to the tank bottom.

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