Dissolved gas separation type jet flotation column

Abstract

The invention discloses a dissolved gas separation type jet flotation column which comprises a flotation column body, a jet cavitation device is installed in the flotation column body, a circulating pump and a pressurizing barrel are sequentially connected to a bottom outlet of the flotation column body in series, and the output end of the pressurizing barrel is connected with the liquid input end of the jet cavitation device; and bubbles with the diameter being 10-100 microns can be generated in ore pulp ejected by the jet flow type cavitation device, and bubbles with the diameter being 60-200 microns can be generated in ore pulp output from the interior of the pressurizing barrel. The circulation loop combines two bubble forming mechanisms of'dissolved gas precipitation 'and'cavitation shearing', multi-scale bubble combination is achieved, small-size bubbles improve the collision probability with fine particles, large-size bubbles provide enough buoyancy to carry the particles to float upwards, capture and secondary mineralization efficiency of the fine particles is synergistically enhanced, and the micro-particle capturing and secondary mineralization efficiency is improved. The defects that single small-size bubbles are insufficient in buoyancy and difficult to secondarily mineralize are effectively overcome, and the problem that single large-size bubbles are low in micro-fine particle capturing probability is solved.

Description

TECHNICAL FIELD

[0001] The present application mainly relates to the technical field of microbubble flotation, and particularly relates to a flotation column. BACKGROUND

[0002] Low flotation efficiency of micro-fine particle minerals is a big problem in the field of mineral processing. Micro-fine particle minerals have the characteristics of small mass, high surface energy and complex interface action. Due to the small mass, the inertia is insufficient, and it is difficult to break through the liquid film resistance to complete adsorption, resulting in low collision probability of micro-fine particles and gas bubbles. At the same time, micro-fine particles are easily entrained into the froth layer by water flow, thereby causing the grade of concentrate to decrease. The high surface energy makes the particles easily agglomerate or non-selectively cover due to surface charge, thereby causing the separation precision to decrease. The interface action is complex, the adsorption of reagents is unstable, and the conventional collectors are difficult to effectively cover the superfine surface, and the excessive use of adjusting agents will affect the stability of froth.

[0003] Microbubble flotation is a flotation technology for improving the efficiency of mineral separation by regulating the characteristics of micron-sized bubbles. When it is applied to the flotation of micro-fine particle minerals, the existing technology usually reduces the bubble size to adapt to the characteristics of micro-fine particle minerals, such as small mass, high surface energy and complex interface action. However, if all the bubble sizes are small, the bubbles do not have enough buoyancy to carry the particles to float up, thereby making it difficult to complete the secondary mineralization, and resulting in poor flotation effect. SUMMARY

[0004] The technical problem to be solved by the present application is how to configure the bubble size to improve the flotation effect.

[0005] To solve the above technical problems, the present application adopts the following technical scheme: The application discloses a dissolved air flotation column, which comprises a flotation column body, a jet cavitation device is arranged in the flotation column body, a circulating pump and a pressure boosting cylinder are sequentially connected in series at the bottom outlet of the jet cavitation device, and the output end of the pressure boosting cylinder is connected with the liquid input end of the jet cavitation device; the jet cavitation device can generate bubbles with a diameter of 10-100 microns in the ejected ore slurry, and the pressure boosting cylinder can generate bubbles with a diameter of 60-200 microns in the output ore slurry in the pressure boosting cylinder. A first closed loop circulation is formed by the circulating pump, the pressure boosting cylinder and the jet cavitation device, the ore slurry is pressurized and dissolved air in the pressure boosting cylinder, when the pressurized ore slurry is discharged from the pressure boosting cylinder, large bubbles with a diameter of 60-200 microns are separated out due to pressure reduction, and small bubbles with a diameter of 10-100 microns are generated by the cavitation shearing of the jet cavitation device. That is to say, the circulation loop combines the two bubble forming mechanisms of "dissolved air separation" and "cavitation shearing", realizes multi-scale bubble combination, the small bubbles improve the collision probability with fine particles, the large bubbles provide sufficient buoyancy to carry the particles to float up, and thus the capture and secondary mineralization efficiency of the fine particles are synergistically enhanced, the defects of insufficient buoyancy and difficulty in secondary mineralization of single-size small bubbles are solved, and the problem of low capture probability of single-size large bubbles on the fine particles is avoided.

[0006] As a further improvement of the above technical solution: The jet cavitation device is a Venturi tube. The structure of the Venturi tube is based on Bernoulli effect, a low pressure area is formed at the throat, air is self-sucked and small bubbles with a diameter of 10-100 microns are generated by shearing, the structure is simple, energy consumption is low, the structure is suitable for industrial scale ore slurry processing capacity, and the problems of serious bubble breaking and merging in a large-scale system can be avoided, the stability of the small bubbles is ensured, and the adsorption effect of the fine particles is improved.

[0007] The output end of the jet cavitation device is located in the middle of the flotation column body. The output end of the jet cavitation device is located in the middle, so that the ore slurry containing bubbles can be directly mixed with the main stream of the ore slurry in the middle section of the flotation column body, the bubbles and the ore slurry can be fully mixed, the contact time of the bubbles and the particles is prolonged, the mineralization efficiency is improved, the bubbles are prevented from overflowing or gathering too early, the flotation process is optimized, and the capture capacity of the fine particles is improved.

[0008] The pressure value in the pressure boosting cylinder ranges from 0.2 MPa to 0.4 MPa. The pressure range ensures moderate dissolution of air in the ore slurry, the bubbles with a diameter of 60-200 microns are separated out when the pressure is released, the bubble size is uniform and not easy to break, the subsequent cooperation of the small bubbles in carrying the particles is ensured, the problems of insufficient buoyancy caused by too small bubbles and poor stability caused by too large bubbles are avoided, and the uniformity of the bubbles and the flotation efficiency are improved.

[0009] The dissolved air precipitation type jet flotation column also comprises a circulating mechanism for adjusting the liquid level in the flotation column body, which is in communication with the flotation column body. By actively regulating the liquid level in the flotation column body, the large fluctuations in the liquid level caused by the large amount of useful minerals floating out can be avoided. The stability of the liquid level can ensure the uniformity of the rising path of the bubbles in the column, reduce the uneven contact between the bubbles and the particles caused by the fluctuations in the liquid level, and thus avoid the decrease in the concentrate grade or the decrease in the recovery rate, ensuring the continuity and stability of the flotation process, and adapting to the needs of industrial mass production.

[0010] The circulating mechanism comprises a stirring barrel, the output end of which is in communication with a pulp feeding port formed on the flotation column body. The stirring barrel can pre-mix and temporarily store the pulp entering the flotation column. Through stirring, the reagents (such as collectors and regulators) in the pulp can be uniformly dispersed, avoiding excessive or insufficient local reagent concentration. The uniform distribution of reagents can ensure that the conventional collectors effectively cover the surface of fine particles, without the need for excessive use of regulators (to avoid affecting the stability of the foam), while ensuring the consistency of the pulp concentration, providing a uniform material basis for subsequent bubble mineralization, and improving the separation accuracy.

[0011] The first input end of the stirring barrel is in communication with a tailings outlet formed on the flotation column body, and the second input end is in communication with an external fresh pulp source. The double-input end design of the stirring barrel forms a "tailings circulation-fresh pulp supplement" loop, which can re-introduce the tailings from the lower section of the flotation column into the system, allowing the fine particles in the tailings to be given a second chance of flotation, thereby improving the overall recovery rate of the minerals. On the other hand, the mixing of fresh pulp and circulating tailings can maintain the stability of the pulp concentration (avoiding fluctuations in the concentration of single fresh pulp affecting the flotation effect), ensuring the consistency of the bubble and particle mineralization environment, and further improving the separation stability.

[0012] The pulp feeding port is located in the middle section of the flotation column body, and the tailings outlet is located in the lower section of the flotation column body; the output end of the stirring barrel is provided with a peristaltic pump or a feeding pump. The pulp feeding port located in the middle section can directly interface with the bubbles output from the jet type cavitation device, shortening the contact distance between the pulp and the bubbles and improving the mineralization efficiency; the tailings outlet located in the lower section can quickly collect the un-mineralized tailings, avoiding their accumulation in the column affecting the flow field. At the same time, the peristaltic pump or feeding pump at the output end of the stirring barrel can provide precise flow control, combined with liquid level detection and PID control, to realize automatic real-time regulation of the liquid level. By adjusting the speed of the peristaltic pump or feeding pump, the fluctuations in the liquid level can be immediately compensated for, without relying on experience, ensuring that the liquid level in the flotation column is always stable within the optimal mineralization range, further ensuring the stability of the concentrate grade and recovery rate. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a structural diagram of a dissolved air precipitation type jet flotation column.

[0014] The labels in the diagram represent: 1. Flotation column; 11. Slurry feed inlet; 12. Tailings outlet; 13. Concentrate froth outlet; 2. Jet cavitation device; 3. Circulating pump; 4. Booster cylinder; 5. Circulation mechanism; 51. Stirring tank; 511. Output end; 512. First input end; 513. Second input end; 52. Peristaltic pump or feed pump. Detailed Implementation

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0016] Example 1 like Figure 1 As shown, the dissolved gas evolution jet flotation column of this embodiment includes a flotation column body 1. A venturi tube-type jet cavitation device 2 is installed inside the flotation column body 1. A circulating pump 3 and a pressure booster cylinder 4 are connected in series at the bottom outlet of the cavitation device 2. The pressure value inside the pressure booster cylinder 4 ranges from 0.2 MPa to 0.4 MPa, and the output end of the pressure booster cylinder 4 is connected to the liquid input end of the jet cavitation device 2. The slurry ejected by the jet cavitation device 2 can generate bubbles with a diameter of 10 μm to 100 μm, and the slurry output from inside the pressure booster cylinder 4 can generate bubbles with a diameter of 60 μm to 200 μm. Specifically, the output end of the jet cavitation device 2 is located in the middle of the flotation column body 1. More specifically, the dissolved gas evolution jet flotation column also includes a circulation mechanism 5 connected to the flotation column body 1 for adjusting the hydraulic pressure height inside the flotation column body 1. The circulation mechanism 5 includes a stirring tank 51, the output end 511 of which is connected to the slurry feed inlet 11 formed on the flotation column body 1. The first input end 512 of the stirring tank 51 is connected to the tailings outlet 12 formed on the flotation column body 1, and its second input end 513 is connected to an external fresh slurry source. The slurry feed inlet 11 is located in the middle section of the flotation column body 1, and the tailings outlet 12 is located in the lower section of the flotation column body 1. The output end 511 of the stirring tank 51 is equipped with a peristaltic pump or a feed pump 52.

[0017] The iron ore after grinding is adjusted to a pulp with a concentration of 30-40wt%, the pulp is fed into the stirring barrel 51 from the second input end 513, and 500g / t of corn starch and 250g / t of sodium oleate are added into the stirring barrel 51, the material is stirred uniformly in the stirring barrel 51, and then is sent into the flotation column body 1 through the peristaltic pump or the ore feeding pump 52 and the pulp feeding port 11, after the flotation liquid level is stabilized to the preset height, the speed of the peristaltic pump or the ore feeding pump 52 and the valve of the tailing outlet 12 are adjusted to keep the liquid level stable, and the circulating pump 3 is opened to make the pulp in the flotation column pass through the pressure cylinder 4 and the jet cavitation device 2 in turn and then return to the flotation column body 1, in this process, the jet cavitation device 2 emits bubbles with a diameter of 10-100μm in the pulp, and the pressure cylinder 4 outputs bubbles with a diameter of 60-200μm in the pulp, and the mineral particles in the pulp are mineralized with the bubbles. In the flotation column body 1, the bubbles float from the middle of the flotation column body 1 to the upper part of the flotation column body 1, and are discharged from the concentrate froth outlet 13. When the flotation process is completed, the circulating pump 3 and the peristaltic pump or the ore feeding pump 52 are closed, and the valve of the tailing outlet 12 is opened, and the flotation tailings are discharged into the stirring barrel 51 through the tailing outlet 12.

[0018] The flotation indexes are shown in Table 1 below.

[0019] Table 1: Flotation indexes of Example 1

[0020] Comparative Example 1 The same reagents as in Example 1 are used, and the flotation indexes of the laboratory mechanical stirring flotation machine are shown in Table 2 below.

[0021] Table 2: Flotation indexes of Comparative Example 1

[0022] It can be seen that the same iron ore is floated by the dissolved gas jet flotation column, and the flotation recovery is higher than that of the conventional mechanical stirring flotation machine.

[0023] Example 2 The dissolved gas jet flotation column used in this example is the same as in Example 1.

[0024] The copper ore after grinding is adjusted to a pulp with a concentration of 30-40wt%, the pulp is fed into the stirring barrel 51 from the second input end 513, and 100g / t of sodium carboxymethyl cellulose and 150g / t of butyl xanthate are added into the stirring barrel 51, the material is uniformly stirred in the stirring barrel 51, and then is sent into the column body 1 of the flotation column through the peristaltic pump or the ore feeding pump 52 through the pulp feeding port 11, after the liquid level is stabilized to the preset height, the speed of the peristaltic pump or the ore feeding pump 52 and the valve of the tailings outlet 12 are adjusted to keep the liquid level stable, and the circulating pump 3 is opened to make the pulp in the flotation column circulate back to the column body 1 of the flotation column through the pressure cylinder 4 and the jet cavitation device 2 in turn, in this process, the bubbles with a diameter of 10-100μm are generated in the pulp jetted out of the jet cavitation device 2, and the bubbles with a diameter of 60-200μm are generated in the pulp output from the pressure cylinder 4, and the mineral particles in the pulp are mineralized with the bubbles. In the column body 1 of the flotation column, the bubbles float from the middle part of the column body 1 to the upper part of the column body 1, and are discharged from the concentrate froth outlet 13. When the flotation process is completed, the circulating pump 3 and the peristaltic pump or the ore feeding pump 52 are closed, and the valve of the tailings outlet 12 is opened, and the flotation tailings are discharged into the stirring barrel 51 through the tailings outlet 12.

[0025] The flotation indexes are shown in Table 3 below.

[0026] Table 3: Flotation indexes of Example 2

[0027] Comparative Example 2 The same reagents as in Example 2 are used, and the flotation indexes of the laboratory mechanical stirring flotation machine are shown in Table 4 below.

[0028] Table 4: Flotation indexes of Comparative Example 1

[0029] It can be seen that the same copper ore is floated by using the dissolved gas jet flotation column, and the flotation recovery is higher than that of the conventional mechanical stirring flotation machine.

[0030] Although the present application has been disclosed with reference to the preferred embodiments above, it is not intended to limit the present application. Any person skilled in the art can make many possible changes and modifications to the technical solutions disclosed above, or modify equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the content of the technical solutions of the present application, shall fall within the scope of protection of the technical solutions of the present application.

Claims

1. A dissolved gas precipitation jet flotation column, comprising a flotation column body (1), characterized in that: The flotation column (1) is equipped with a jet cavitation device (2), and a circulating pump (3) and a booster cylinder (4) are connected in series at its bottom outlet. The output end of the booster cylinder (4) is connected to the liquid input end of the jet cavitation device (2). The jet cavitation device (2) can generate bubbles with a diameter of 10μm-100μm in the slurry ejected, and the pressurizing cylinder (4) can generate bubbles with a diameter of 60μm-200μm in the slurry output from inside.

2. The dissolved gas precipitation jet flotation column according to claim 1, characterized in that: The jet cavitation device (2) is configured as a venturi tube.

3. The dissolved gas precipitation jet flotation column according to claim 1, characterized in that: The output end of the jet cavitation device (2) is located in the middle of the flotation column (1).

4. The dissolved gas precipitation jet flotation column according to claim 1, characterized in that: The pressure range inside the booster cylinder (4) is 0.2MPa-0.4MPa.

5. The dissolved gas precipitation jet flotation column according to claim 1, characterized in that: The dissolved gas precipitation jet flotation column also includes a circulation mechanism (5) connected to the flotation column body (1) for adjusting the hydraulic pressure inside the flotation column body (1).

6. The dissolved gas precipitation jet flotation column according to claim 5, characterized in that: The circulation mechanism (5) includes a stirring tank (51), the output end (511) of which is connected to the slurry feed port (11) formed on the flotation column (1).

7. The dissolved gas precipitation jet flotation column according to claim 6, characterized in that: The first input end (512) of the mixing tank (51) is connected to the tailings outlet (12) formed on the flotation column (1), and its second input end (513) is connected to an external fresh slurry source.

8. The dissolved gas precipitation jet flotation column according to claim 7, characterized in that: The slurry feed inlet (11) is located in the middle section of the flotation column (1), and the tailings outlet (12) is located in the lower section of the flotation column (1); the output end (511) of the stirring tank (51) is equipped with a peristaltic pump or a feed pump (52).

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