Microbubble reinforced metal leaching system and method

Abstract

The invention provides a microbubble reinforced metal leaching method which comprises the following steps: crushing ore to obtain ore powder; mixing the mineral powder and the leaching agent solution to obtain ore pulp; microbubbles are introduced into the ore pulp, and a leaching reaction is carried out; and after the leaching reaction, carrying out solid-liquid separation to obtain a leaching solution. The microbubbles are introduced into a leaching system, and the mass transfer efficiency and reaction activity of gas oxidants such as oxygen and the like in a solution are remarkably enhanced by utilizing the characteristics of huge specific surface area, high interface free energy, capability of spontaneously generating active oxygen and the like of the microbubbles. The method can efficiently oxidize and decompose sulfide mineral crystal lattices or promote dissolution of oxidized ores under normal pressure and relatively mild conditions, so that the leaching rate and the leaching rate of valuable metals such as copper, nickel and cobalt are greatly increased, and the method is particularly suitable for complex and difficult-to-treat ores such as surface-generated nickel oxide ores and nickel sulfide concentrates and has the advantages of being low in cost, environmentally friendly and simple in process.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, and in particular to a microbubble-enhanced metal leaching system and method. Background Technology

[0002] Copper, nickel, and cobalt are important strategic metals. Their primary mineral resources, such as nickel sulfide concentrate and chalcopyrite, are often difficult to process efficiently and economically due to their complex mineral structure and fine grain size. Traditional hydrometallurgical leaching technology, especially when processing sulfide ores, heavily relies on high-temperature and high-pressure autoclaves or large amounts of strong chemical oxidants (such as chlorine and ferric oxide) to destroy the mineral lattice. This has drawbacks such as high equipment investment, high energy consumption, high operational risks, and serious environmental pollution.

[0003] CN202210007900.3 discloses a method for selectively leaching nickel sulfide concentrate under mild pressure, reducing the temperature to 120-150℃ and the oxygen partial pressure to 0.1-0.8MPa. However, it still relies on a high-pressure autoclave and suffers from the problem of selective separation of iron and copper. CN202411189188.9 discloses a chalcopyrite leaching method using hydrogen peroxide in synergistic bio-oxidation, which removes the surface passivation layer through a Fenton-like reaction. However, this method still relies on an external oxidant (hydrogen peroxide), and the biological process is slow. CN202510360691.4 discloses an in-situ depassivation bioleaching method, which uses microorganisms to reduce and remove the passivation film in an anaerobic-aerobic alternating environment. This process is time-consuming and requires stringent control of microbial activity and environment.

[0004] In summary, although existing technologies have made progress in improving traditional leaching processes, most have failed to fundamentally solve their inherent defects: biological methods suffer from slow reaction kinetics and complex process control; while pressure leaching still faces challenges such as high equipment requirements and high energy consumption. In particular, the low solubility and poor mass transfer efficiency of gaseous oxidants such as oxygen in atmospheric pressure slurry are the core bottlenecks that limit the industrial application of atmospheric pressure leaching technology, resulting in long reaction cycles and unsatisfactory metal recovery rates.

[0005] Therefore, developing a novel leaching technology that can significantly enhance oxygen mass transfer and oxidation processes under mild (normal pressure, medium and low temperature) conditions without relying on biological processes or complex external agents is of great significance for reducing metallurgical costs and realizing the green and efficient utilization of mineral resources. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention provides a leaching method and system for valuable metals. The leaching method provided by the present invention utilizes the unique gas-liquid interface properties of microbubbles, combined with their high mass transfer efficiency and spontaneous free radical generation characteristics, to significantly enhance the utilization efficiency of oxidants such as oxygen under normal pressure and mild conditions, thereby achieving efficient leaching of valuable metals such as copper, nickel, and cobalt. This method eliminates the need for high-temperature and high-pressure equipment, significantly reducing oxidant consumption and equipment investment costs. The process is simple and environmentally friendly, providing a new approach for the green and efficient utilization of primary mineral resources.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for microbubble-enhanced metal leaching, the method comprising the following steps:

[0009] The ore is crushed to obtain ore powder; the ore powder and leaching agent solution are mixed to obtain ore slurry; microbubbles are introduced into the ore slurry to carry out a leaching reaction; after the leaching reaction, solid-liquid separation is performed to obtain leachate.

[0010] The core working principle of this invention lies in the multiple enhancing roles played by microbubbles during the leaching process. First, their enormous specific surface area and long residence time significantly improve the dissolution rate and mass transfer efficiency of oxygen in the slurry. Second, at the moment of generation and collapse, the gas-liquid interface of microbubbles can generate localized high-temperature and high-pressure extreme environments, and spontaneously generate reactive oxygen species, etc. These strong oxidizing substances can effectively attack and destroy the crystal lattice of sulfide minerals, oxidizing low-valence valuable metals (or associated sulfur elements) to higher valence states that are easier to leach, thereby significantly accelerating the metal dissolution process. For oxidized minerals, the intense interfacial movement of microbubbles can also peel off the passivation layer on the mineral surface, continuously exposing fresh reaction surfaces.

[0011] As a preferred embodiment of the present invention, the ore includes sulfide ore and / or oxide ore.

[0012] Preferably, the sulfide ore includes chalcopyrite and / or nickel sulfide concentrate.

[0013] Preferably, the oxide ore includes supergene nickel oxide ore.

[0014] Preferably, the ore contains any one or a combination of at least two of the metals selected from copper, nickel, or cobalt.

[0015] As a preferred embodiment of the present invention, the leaching agent solution includes an acidic solution and / or an alkaline solution.

[0016] Preferably, the acidic solution includes any one or a combination of at least two of sulfuric acid, hydrochloric acid, or nitric acid solutions.

[0017] Preferably, the alkaline solution comprises any one or a combination of at least two of the following: an ammonia-ammonium carbonate system, an ammonia-ammonium sulfate system, or a sodium hydroxide solution.

[0018] As a preferred technical solution of the present invention, the solid-liquid ratio of the mineral powder to the leaching agent solution is 1:(3-10)g / mL, for example, it can be 1:3g / mL, 1:5g / mL, 1:7g / mL, 1:9g / mL or 1:10g / mL, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] As a preferred technical solution of the present invention, the gas in the microbubbles includes any one or a combination of at least two of air, oxygen-enriched air, or oxygen.

[0020] As a preferred technical solution of the present invention, the diameter of the microbubbles is 1-100μm, for example, it can be 1μm, 20μm, 40μm, 60μm, 80μm or 100μm, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] As a preferred embodiment of the present invention, the proportion of 200 mesh in the mineral powder is >90%.

[0022] In a second aspect, the present invention provides a microbubble-enhanced metal leaching system, wherein the leaching system is obtained by means of the method described in the first aspect.

[0023] Preferably, the leaching system includes a reactor body, a stirring device, a microbubble generator, a gas source, and a heating device.

[0024] As a preferred technical solution of the present invention, the microbubble generator includes any one of the Venturi type, rotary shear type, or pressurized dissolution decompression gas release type microbubble generator.

[0025] As a preferred embodiment of the present invention, the leaching system includes a data acquisition and control system.

[0026] Compared with existing technical solutions, the present invention has at least the following beneficial effects:

[0027] This invention introduces microbubbles into the leaching system, which, by utilizing their large specific surface area and high interfacial activity, significantly enhances the mass transfer efficiency and reactivity of oxygen in the slurry. Furthermore, microbubbles can spontaneously generate active oxygen species at the gas-liquid interface, thereby efficiently disrupting the mineral lattice under normal pressure and mild conditions. This significantly increases the leaching rate and extraction rate of valuable metals such as copper, nickel, and cobalt, while effectively reducing equipment investment, oxidant consumption, and environmental pollution. This provides a new approach for the green and economical recovery of primary mineral resources. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a microbubble-enhanced oxidation leaching method and system for valuable metals;

[0029] In the diagram: 1-Reactor body, 2-Stirring device, 3-Microbubble generator, 4-Gas source, 5-Heating device. Detailed Implementation

[0030] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0031] It should be clarified that any use of the process provided in the embodiments of the present invention or any substitution or change of conventional data falls within the protection and disclosure scope of the present invention.

[0032] Example 1

[0033] This embodiment provides a microbubble-enhanced metal leaching method, the method comprising the following steps:

[0034] (1) Crush and grind the chalcopyrite to 200 mesh (95%) for later use.

[0035] (2) Take 100 g of mineral powder and mix it with 400 mL of sulfuric acid with a concentration of 50 g / L to prepare a slurry. Transfer the slurry to the reactor and preheat it to 90°C.

[0036] (3) Turn on the agitator (600 rpm) and introduce air into the slurry through the microbubble generator. The gas flow rate is 1.0 L / min and the average diameter of the generated microbubbles is about 50 μm.

[0037] (4) After reacting at 90℃ for 6 hours, the leachate was obtained by filtration. Atomic absorption spectroscopy analysis showed that the copper leaching rate reached 91.5%.

[0038] Example 2

[0039] This embodiment provides a microbubble-enhanced metal leaching method, the method comprising the following steps:

[0040] (1) Grind nickel sulfide concentrate to 325 mesh (90%) and set aside.

[0041] (2) Take 200 g of mineral powder and mix it with 800 mL of 150 g / L sulfuric acid solution to prepare a slurry, and transfer it to a reactor with a heating jacket.

[0042] (3) Turn on the stirring (400 rpm) and heat to 85°C. Introduce oxygen into the slurry through a microbubble generator at a flow rate of 1.5 L / min. The average diameter of the generated microbubbles is about 80 μm.

[0043] (4) After reacting at 85°C for 10 hours, the leachate was obtained by filtration. Analysis showed that the leaching rate of nickel was 96.8% and the leaching rate of copper was 94.1%.

[0044] Example 3

[0045] This embodiment provides a microbubble-enhanced metal leaching system, which includes a reactor body 1, a stirring device 2, a microbubble generator 3, a gas source 4, and a heating device 5. The material inlet of the reactor body 1 is connected to the gas outlet of the microbubble generator 3, the material outlet of the reactor body 1 is connected to the gas inlet of the microbubble generator 3, the material inlet of the microbubble generator 3 is connected to the gas outlet of the gas source 4, and the heating device 5 is wrapped around the outside of the reactor body 1.

[0046] The filtrates provided in Examples 1-2 were tested, and the results are shown in Table 1.

[0047] Table 1

[0048]

[0049] In Table 1, "-" indicates that there is no relevant data.

[0050] The present invention has been illustrated with the above embodiments to illustrate its detailed structural features. However, the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for enhancing metal leaching with microbubbles, characterized in that, The method includes the following steps: The ore is crushed to obtain ore powder; the ore powder and leaching agent solution are mixed to obtain ore slurry; microbubbles are introduced into the ore slurry to carry out a leaching reaction; after the leaching reaction, solid-liquid separation is performed to obtain leachate.

2. The method according to claim 1, characterized in that, The ore includes sulfide ore and / or oxide ore; Preferably, the sulfide ore includes chalcopyrite and / or nickel sulfide concentrate; Preferably, the oxide ore includes supergene nickel oxide ore; Preferably, the ore contains any one or a combination of at least two of the metals selected from copper, nickel, or cobalt.

3. The method according to claim 1 or 2, characterized in that, The leaching agent solution includes an acidic solution and / or an alkaline solution; Preferably, the acidic solution includes any one or a combination of at least two of sulfuric acid, hydrochloric acid, or nitric acid solutions; Preferably, the alkaline solution comprises any one or a combination of at least two of the following: an ammonia-ammonium carbonate system, an ammonia-ammonium sulfate system, or a sodium hydroxide solution.

4. The method according to any one of claims 1 to 3, characterized in that, The solid-liquid ratio of the mineral powder to the leaching agent solution is 1:(3-10)g / mL.

5. The method according to any one of claims 1 to 4, characterized in that, The gas in the microbubbles includes any one or a combination of at least two of air, oxygen-enriched air, or oxygen.

6. The method according to any one of claims 1 to 5, characterized in that, The diameter of the microbubbles is 1-100 μm.

7. The method according to any one of claims 1 to 6, characterized in that, The mineral powder contains more than 90% 200 mesh.

8. A microbubble-enhanced metal leaching system, characterized in that, The leaching system is obtained by the method described in any one of claims 1 to 7; Preferably, the leaching system includes a reactor body, a stirring device, a microbubble generator, a gas source, and a heating device.

9. The leaching system according to claim 8, characterized in that, The microbubble generator includes any one of the following: Venturi type, rotary shear type, or pressurized dissolution depressurization release type microbubble generator.

10. The leaching system according to claim 8 or 9, characterized in that, The leaching system includes a data acquisition and control system.

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