Liquid-liquid-gas three-phase mixed type centrifugal extraction separator and gas phase counter-extraction centrifugal system

Abstract

This invention belongs to the technical field of centrifugal extraction equipment, specifically relating to a liquid-liquid-gas three-phase mixing centrifugal extraction separator and a gas-phase reverse extraction centrifugal system. The drum of this invention has an upward-opening barrel-shaped structure. The bottom of the outer barrel and the bottom of the inner cavity of the shell form a secondary mixing chamber. A dispersion disc is coaxially arranged at the bottom of the outer barrel, and a flow channel hole communicating with the inner cavity of the drum is passed through the bottom of the outer barrel. A bottom cylinder is coaxially arranged on the outer bottom surface of the shell, and a dispersion cylinder is coaxially sleeved inside the bottom cylinder. The dispersion cylinder cavity forms a primary mixing chamber, and a lifting paddle is coaxially installed inside the dispersion cylinder. The inner wall of the bottom cylinder and the outer wall of the dispersion cylinder form an air inlet chamber, which communicates with the gas inlet. Aeration holes are provided on the wall of the dispersion cylinder. A liquid phase feed chamber is also fixedly connected below the bottom cylinder, and a material inlet and an extractant inlet are arranged in the liquid phase feed chamber. This invention has the advantages of compact structure and ease of use, and can achieve efficient input and mixing of gas-liquid three phases, thereby ensuring continuous and high-efficiency production.

Description

Technical Field

[0001] This invention belongs to the technical field of centrifugal extraction equipment, specifically relating to a liquid-liquid-gas three-phase mixed centrifugal extraction separator and a gas-phase reverse extraction centrifugal system. Background Technology

[0002] Centrifugal extraction separators are rapid and efficient liquid-liquid extraction devices that utilize centrifugal force to achieve the extraction and separation of liquid and liquid phases. They can perform multiple functions such as liquid-liquid mixing, mass transfer, reaction, extraction, washing, and separation. The applicant has previously applied for a series of related patents, including "CN210302506U". However, current centrifugal extraction separators, as mentioned above, only achieve the extraction and separation of liquid and liquid phases. With the development of solvent technology, especially the emergence of various new synthetic extractants, it is necessary to maintain the pH value of the material system during the extraction process. Often, a specific gas needs to be introduced to facilitate the reaction and precipitation of soluble salts. Currently, in industrial applications, the material to be extracted is placed in a container with a certain volume, the gas is directly added, and stirring is performed. After the reaction is complete, it is then placed in another clarifying container for sedimentation separation. Taking carbon dioxide as the gas phase for back-extraction as an example, refer to... Figure 6 As shown, the process involves an atmospheric pressure, elongated reactor. Carbon dioxide gas is typically introduced from the bottom, while the loaded organic phase and pure water are added from the top to a certain quantity. Subsequently, carbon dioxide is introduced for a certain period, with excess carbon dioxide being discharged directly from the top of the reactor. The dissolved gas mixture after the reaction is complete needs to re-enter a mixing and clarification tank for further mixing and reaction in the mixing chamber. Then, it enters the clarification chamber and, under gravity, settles freely for a certain period, achieving oil-water separation. The problems with this conventional engineering method are: First, because the materials need to react with carbon dioxide in the reactor for a certain time, the entire process is intermittent and relatively inefficient. Second, simple stirring is insufficient for thorough mixing and reaction of the gas and materials, further prolonging the reaction time, reducing separation efficiency, and causing continuous gas replenishment and dissipation, resulting in high gas consumption and costs. Third, the numerous auxiliary equipment and long transfer routes lead to poor operational flexibility, high operational difficulty, and significant safety hazards. Finally, once the equipment is finalized, there is little room for adjustment. The mixing effect can only be improved by reducing capacity and feed flow, resulting in poor adaptability and difficulty in meeting the fluctuations in materials and the variables in process parameters. Therefore, this issue urgently needs to be addressed. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a liquid-liquid-gas three-phase mixing centrifugal extraction separator, which has the advantages of compact structure and convenient use, and can achieve efficient input and mixing of gas, liquid and gas phases, thereby ensuring the continuity and high efficiency of production.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A liquid-liquid-gas three-phase mixing centrifugal extraction separator includes a shell and a drum arranged coaxially. A heavy phase outlet N2 and a light phase outlet N3 are arranged on the shell. The drum is characterized by: an upward-opening barrel-shaped structure; a secondary mixing chamber is formed between the bottom of the outer drum and the bottom of the inner cavity of the shell; a dispersion disc is coaxially arranged at the bottom of the outer drum, and a flow channel hole communicating with the inner cavity of the drum is passed through the bottom of the outer drum; a bottom cylinder is also coaxially arranged on the outer bottom surface of the shell, and a dispersion cylinder is coaxially sleeved inside the bottom cylinder, forming a primary mixing chamber communicating with the secondary mixing chamber; a lifting paddle is coaxially installed inside the dispersion cylinder and fixed to the drum; an air inlet chamber is formed between the inner wall of the bottom cylinder and the outer wall of the dispersion cylinder, communicating with an internal gas inlet N40; an aeration hole communicating with the primary mixing chamber is provided on the wall of the dispersion cylinder; a liquid phase feed chamber communicating with the primary mixing chamber is also fixedly connected below the bottom cylinder, with a material inlet N6 and an extractant inlet N7 arranged at the liquid phase feed chamber.

[0005] Preferably, the space above the opening of the drum forms a gas collection chamber, and a gas outlet N1 is arranged at the top of the gas collection chamber; the centrifugal extraction separator also includes a venturi tube; the inlet of the venturi tube constitutes an external gas interface N5, the outlet constitutes an internal gas inlet N40, and the negative pressure inlet N4 of the venturi tube is connected to the gas outlet N1 via a return gas pipeline.

[0006] Preferably, the dispersion disk includes a chassis and circumferentially distributed arc-shaped blades on the chassis. The flow channel holes are arranged on the chassis surface between the near-axial end of the arc-shaped blades and the axis of the drum, and each flow channel hole is opened on the same pitch circle of the chassis.

[0007] Preferably, the curvature of each arc blade is opposite to the direction of rotation of the drum, and the height of the far-axis end of the arc blade is higher than the height of the near-axis end, so that the unfolded shape of the arc blade presents a trapezoidal structure.

[0008] Preferably, a dispersion hole is formed through the blade surface at the far-axis end of the arc-shaped blade.

[0009] Preferably, the chassis forms the bottom of the drum and is coaxially fixed to the bottom flange of the drum; a mating ring is provided in the inner cavity of the shell, and the outer edge of the bottom flange overlaps the ring from top to bottom, and the two form a dynamic and static sealing fit through a sealing assembly.

[0010] Preferably, the sealing assembly is a labyrinth seal, a stepped seal, or an embedded spiral seal.

[0011] Preferably, pressure gauges are installed at both the return gas pipeline and the external gas interface N5; the material inlet N6 and the extractant inlet N7 are symmetrically arranged along the axis of the liquid phase feed chamber, and the vent N8 is located at the bottom of the liquid phase feed chamber.

[0012] Preferably, the gas-liquid phase reverse extraction centrifugal system is characterized by comprising three sets of liquid-liquid-gas three-phase mixing centrifugal extraction separators, which are here named, in sequence, the first separator, the second separator, and the third separator, wherein: The first separator's material inlet N6 receives the loaded organic phase, and its heavy phase outlet N2 outputs lithium bicarbonate solution; the first separator's light phase outlet N3 is connected to the second separator's material inlet N6, and the first separator's extractant inlet N7 is connected to the second separator's heavy phase outlet N2. The light phase outlet N3 of the second separator is connected to the material inlet N6 of the third separator, and the extractant inlet N7 of the second separator is connected to the heavy phase outlet N2 of the third separator. The light phase outlet N3 of the third separator outputs the delithiated organic phase, and the extractant inlet N7 of the third separator inputs pure water. All gas external interfaces N5 are connected to an external gas source.

[0013] The beneficial effects of this invention are as follows: 1) Through the above solution, on the one hand, relying on the three-inlet structure of the present invention, the mixing and reaction of the liquid, liquid, and gas phases in the same machine can be achieved, realizing the linearization and continuity of the entire production process, and significantly improving production efficiency. On the other hand, relying on the design of the primary mixing chamber and the dispersion cylinder with aeration holes, the liquid phase, as it moves from bottom to top, can be continuously stirred, dispersed, and mixed by the lifting paddle along with the aerated gas phase in the primary mixing chamber. Then, it undergoes secondary mixing in the secondary mixing chamber, and finally enters the rotating drum through the flow hole. The process can maximize the thorough mixing and reaction of the gas and liquid phases. Finally, the overall equipment is compact and reasonable, and a single unit can realize the entire mixing process without additional auxiliary equipment, further improving the simplicity and safety of operation.

[0014] 2) As a further preferred embodiment of the above solution, the present invention takes into account the issue of gas consumption, thereby adding a gas collection chamber and a return gas pipeline, and using the negative pressure generated by the intake air to ensure the return gas effect of the return gas pipeline through a Venturi tube. Ultimately, it ensures that even if some gas phase is not completely mixed in the first and second mixing stages, it can still flow back to the inlet through the return gas pipeline to achieve a continuous gas supply effect, so as to minimize gas consumption, reduce costs, and reduce the pollution of the gas phase to the external environment.

[0015] 3) Depending on the material characteristics, the secondary mixing chamber can be a replaceable structure in actual use, meaning that different volumes of secondary mixing chambers can be used to achieve a mixing effect that is more suitable for the material. Specifically, if it is necessary to enhance the gas-liquid mixing effect and increase the mixing time, the volume of the secondary mixing chamber should be increased first, while ensuring the production capacity; conversely, if the gas-liquid mixing effect is weakened and the mixing time is reduced, the volume of the secondary mixing chamber can be decreased. This increases the applicability of the equipment and provides greater flexibility for adjustment.

[0016] Thus, in response to the actual needs of the new extractant for gas charging and the shortcomings of existing technologies, this invention has developed a Venturi-type gas delivery structure, combined with introductory stirring and mixing and secondary gas mixing, and undissolved gas recovery and other technical means, to achieve the purpose of efficient gas input, mixing and gas saving, so as to ultimately ensure the continuity of production. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the liquid-liquid-gas three-phase mixing centrifugal extraction separator of the present invention; Figure 2 This is a schematic diagram of the three-phase mixing state of the present invention; Figure 3 This is a schematic cross-sectional view of the distribution disk. Figure 4 This is a top view of the dispersion disk; Figure 5 for Figure 2 A magnified view of part I; Figure 6 This is a schematic diagram of the gas reverse extraction centrifugation system of the present invention; Figure 7 This is a schematic diagram of a traditional carbon dioxide back-extraction device.

[0018] The actual correspondence between the reference numerals and component names in this invention is as follows: A - First separator; B - Second separator; C - Third separator; a-Secondary mixing chamber; b-Primary mixing chamber; c-Gas collection chamber; d-Liquid phase feed chamber; 10-Housing shell; 11-Matching convex ring; 20-Drum; 21-Dispersion disc; 22-Flow channel hole; 23-Arc-shaped blade; 23a-Dispersion hole; 24-Bottom flange; 31-Bottom cylinder; 32-Dispersion cylinder; 33-Lifting paddle; 40 - Venturi tube; 50 - Sealing assembly; 60 - Return gas line. Detailed Implementation

[0019] For ease of understanding, this section combines... Figure 1-6 The specific structure and operation of the present invention are further described below: The specific implementation and structure of the liquid-liquid-gas three-phase mixing centrifugal extraction separator of the present invention are as follows: Figure 1As shown, its main components consist of a main motor constituting the power source, a rotating drum 20, a housing 10, a frame, and a gas conveying assembly. In the design, the housing 10 has a gas outlet N1 at the top; a heavy phase outlet N2 and a light phase outlet N3 on the upper side; and a material inlet N6, an extractant inlet N7, an vent N8, and an internal gas inlet N40 at the bottom. The gas conveying assembly has an external gas interface N5 and a negative pressure inlet N4.

[0020] The output shaft of the power source, the drum 20, and the housing 10 are all coaxially arranged to ensure that the drum 20 can rotate at high speed under the drive of the power source, and the direction of rotation is generally clockwise when viewed from above. The following description assumes that the drum 20 rotates clockwise when viewed from above: The liquid phase feed chamber d is located at the bottom of the bottom cylinder 31 and is coaxial with it. The liquid phase feed chamber d is equipped with a material inlet N6 and an extractant inlet N7, and an exhaust port N8 is located at the bottom of the liquid phase feed chamber d. The material inlet N6 and the extractant inlet N7 are generally symmetrically arranged to facilitate the initial mixing of the two liquid phases upon entry.

[0021] The rotary drum 20 is the core of the liquid-liquid-gas three-phase mixing centrifugal extraction separator. It is the working area where gas and various liquid phase materials are stirred, mixed, reacted, and separated. During production, the rotation speed of the rotary drum 20 can be adjusted through an external electrical control system to obtain a suitable separation factor so as to match the specific material characteristics and process requirements.

[0022] In specific design, such as Figure 1-2 As shown, the housing 10 is coaxially mounted outside the drum 20 and fixedly connected to the frame. The upper part of the housing 10, i.e., the cylindrical section containing the heavy phase outlet N2 and the light phase outlet N3, is the collection chamber for the separated materials. The labyrinth ring formed by the combination of the lower and upper labyrinths, i.e., the sealing assembly 50, together with the bottom of the drum 20 and the bottom of the housing 10, forms the secondary mixing chamber a. The bottom cylinder 31 is coaxially fastened to the bottom of the housing 10 by bolts. The bottom side of the bottom cylinder 31 is connected to the gas conveying assembly through the gas inlet N40. The interior of the bottom cylinder 31, together with the dispersion cylinder 32 and the lifting paddle 33, forms the primary mixing chamber b. The dispersion cylinder 32 is fixed to the bottom of the bottom cylinder 31 and coaxial with it. The dispersion cylinder 32 is machined with a series of aeration holes to facilitate the aeration and dispersion of the incoming gas, making the gas more easily soluble in the liquid phase. During the design, the inner diameter of the dispersion cylinder 32 needs to be slightly larger than the outer diameter of the lifting paddle 33, not only for ease of assembly but also to take into account the vibration space requirements of the lifting paddle 33 during operation.

[0023] The lifter 33 is a right-handed helix, and its direction of rotation is determined by the rotation of the drum 20. When the drum 20 rotates clockwise when viewed from above, the helix of the lifter 33 is right-handed, which is necessary to lift the dissolved gas mixture in the primary mixing chamber b to the secondary mixing chamber a. The lifter 33 is independently and coaxially fixed to the dispersion disk 21 that forms the bottom of the drum 20, and rotates synchronously with the drum 20. Because the lifter 33 is independent, a lifter with a smaller pitch and a larger helix angle can be used under stronger mixing conditions. If it is replaced together with the bottom cylinder 31, the diameter of the lifter 33 can also be changed accordingly to achieve a stronger stirring and mixing effect.

[0024] Inside the secondary mixing chamber a, to further rapidly dissolve the gas phase into the liquid phase, 4 to 12 arc-shaped blades 23 are evenly distributed at the bottom of the dispersion disk 21. Viewed from below, the arc-shaped blades 23 exhibit a clockwise curvature. Figure 4 As shown. And with Figure 3 Viewed from the perspective shown, looking directly at the curved blades 23, it can be seen that the height of the far-axis end of each curved blade 23 is higher, and the height of the proximal end is lower, with an overall trapezoidal shape when unfolded. A series of dispersion holes 23a are provided on the wider part of the curved blades 23 away from the proximal end, i.e., on the blade surface where the far-axis end is located, which also serves an aeration function. To facilitate connection with the main shaft, the coupling seat of the rotating drum 20 can be designed as part of the dispersion disk 21, so that the dispersion disk 21 can also serve as the drum base of the rotating drum 20; the middle of the coupling seat is a bushing, directly connected to the main shaft, transmitting torque through a key for synchronous rotation. Furthermore, as... Figure 3 As shown, several flow channel holes 22 are opened on a certain pitch circle of the dispersion disk 21, that is, the flow channel holes 22 are evenly distributed on the dispersion disk 21, so as to connect the secondary mixing chamber a with the inner cavity of the drum 20, so that the mixed phase after gas dissolution can enter the interior of the drum 20 through the flow channel holes 22.

[0025] To prevent the dissolved gas mixture from overflowing into the annular cavity between the outside of the drum 20 and the inside of the shell 10, the dynamic and static sealing between the bottom of the drum 20 and the shell 10 is crucial; even the gas collecting cavity c can be formed by setting corresponding seals at the bottom of the drum 20 and the inner cavity at the bottom of the shell 10. In this invention, the outer edge of the bottom flange 24 at the bottom of the drum 20 for fixing the dispersion disk 21 is provided with a series of grooves to form an upper labyrinth; the mating convex ring 11 is provided with a series of protruding teeth to form a lower labyrinth. The two work together to form a labyrinth seal, preventing the overflow of the dissolved gas mixture. See the specific reference. Figure 5 As shown. Of course, in addition to the labyrinth seal type in this example, other dynamic and static sealing structures such as stepped type and embedded spiral seal can also be designed.

[0026] Regarding gas phase input, such as Figure 1-2As shown, the gas delivery assembly includes a Venturi tube 40. The inlet of the Venturi tube 40 forms an external gas interface N5, which is connected to a gas source. The outlet of the Venturi tube 40 forms an internal gas inlet N40. The negative pressure inlet N4 of the Venturi tube 40 is connected to the gas outlet N1 via a return gas line 60. A pressure gauge is also installed on the pipeline connecting the external gas interface N5 to the gas source to read the inlet pressure. The negative pressure inlet N4 of the Venturi tube 40 is obliquely inserted and fixed to the return gas line 60, and a pressure gauge is also installed on the return gas line 60. According to the Venturi principle, when a fluid of a certain pressure and flow rate is transported from a larger diameter to a smaller diameter, its flow velocity increases and a low-pressure adsorption phenomenon occurs nearby. Therefore, the Venturi tube 40 can rely on low-pressure adsorption to recirculate the gas that has not dissolved in the liquid phase through the gas collecting chamber c, the gas outlet N1, the return gas line 60, and the negative pressure inlet N4.

[0027] To facilitate a further understanding of the present invention, the actual workflow of the present invention is described below in conjunction with the following feeding embodiments.

[0028] During operation, the liquid-liquid-gas three-phase mixing centrifugal extraction separator is started up to the rated speed. In order to quickly reach internal phase equilibrium, the denser phase is generally introduced first. Here, we take the material as the denser phase as an example: With the vent valve N8 closed, the denser material first enters the equipment through the material inlet N6, passes through the liquid phase feed chamber d, and overflows into the primary mixing chamber b. Gas enters the primary mixing chamber b through the gas external interface N5 at a certain pressure and flow rate. With the coordinated action of the dispersion cylinder 32 and the lifting paddle 33, the gas quickly and efficiently dissolves into the material. Under the pumping effect of the lifting paddle 33, the dissolved gas and any undissolved gas enter the secondary mixing chamber a. Again, under the stirring of the dispersion disc 21, the undissolved gas dissolves into the material, forming a higher concentration of dissolved gas. After a certain volume, it enters the drum 20 through the flow channel 22. Because the drum 20 rotates at high speed, a large centrifugal force field is formed inside the drum 20, causing the dissolved gas to slowly separate in sections at the bottom of the drum 20. The denser material is closer to the drum wall, and the less dense material is closer to the center of the drum 20; the gas, being the lightest, is closest to the gas phase zone at the very center of the drum 20. As the dissolved gas material moves upward along the rotating drum 20, material separation intensifies, and gas-liquid separation is essentially completed in the fast-zone section at the upper end of the rotating drum 20. The denser material flows out from the heavy phase outlet N2; the lightest gas phase enters the gas collecting chamber c at the top of the shell 10 from the gas phase zone, and then, under the action of the venturi tube 40, is recirculated through the gas outlet N1, the return gas pipeline 60, and the negative pressure inlet N4. (See details...) Figure 2 As shown.

[0029] Furthermore, such as Figure 2As shown, after the dense material flows out from the heavy phase outlet N2, the less dense organic phase is added through the extractant inlet N7 and enters the equipment. At this time, the feed of the liquid-liquid-gas three-phase mixing centrifugal extraction separator consists of three types: dense material, less dense organic phase, and least dense gas. The dense material enters the equipment through the material inlet N6 and the less dense organic phase enters through the extractant inlet N7 in a certain ratio. After preliminary mixing in the liquid phase feed chamber d, it overflows into the primary mixing chamber b. Subsequently, it is mixed with the gas in the dispersion cylinder 32 and the lifting paddle 33, resulting in rapid and efficient mixing of the gas, material, and organic phases. Under the lifting pump effect of the lifting paddle 33, the dissolved gas mixture and the undissolved gas enter the secondary mixing chamber a. Under the stirring of the dispersion disc 21, the undissolved gas dissolves again, forming a higher concentration of dissolved gas mixture. After a certain volume, it enters the drum 20 through the flow channel hole 22. Because the drum 20 rotates at high speed, a large centrifugal force field is formed inside the drum 20. The dissolved gas mixture slowly separates in the slow zone at the bottom of the drum 20. The denser material is closer to the drum wall, and the less dense organic phase is closer to the center of the drum 20. The gas is the lightest and is relatively close to the gas phase zone at the very center of the drum 20. As the dissolved gas mixture moves upward along the drum 20, the separation intensifies. The liquid-liquid-gas three-phase separation is basically completed in the fast zone at the upper part of the drum 20. The denser material flows out from the heavy liquid outlet N2, and the less dense organic phase flows out from the light phase outlet N3. The lightest gas phase enters the gas collection chamber c at the top of the shell 10 from the gas phase zone. Then, under the Venturi effect of the gas conveying component, it is recirculated through the gas outlet N1, the return gas pipeline 60, and the negative pressure inlet N4.

[0030] Here, we will further illustrate this point by taking the recycling of lithium from retired batteries as an example: After the retirement of power batteries such as lithium iron phosphate and ternary lithium batteries, it is essential to consider recycling their valuable metal elements to ensure the sustainable development of metal resources and reduce the environmental pollution caused by the increasing accumulation of waste lithium batteries. Centrifugal solvent extraction technology has received widespread attention in this regard. The process generally includes battery pretreatment, leaching purification, centrifugal extraction-washing-back-extraction-saponification, concentration and crystallization, and lithium product refining. In this process, to reduce the generation of high-sodium wastewater, the traditional method of adding sodium carbonate by directly adding carbon dioxide gas during the back-extraction stage is being considered.

[0031] It is precisely because of this that such a situation arose. Figure 7 The traditional carbon dioxide back-extraction unit shown is an example. As mentioned earlier, this type of carbon dioxide back-extraction unit has many problems due to its highly intermittent process flow, numerous pieces of equipment, long transfer routes, high gas consumption, and low production efficiency.

[0032] Therefore, this invention enables the efficient and rapid design of novel centrifugal processes, specifically including: During assembly, this invention connects multiple liquid-liquid-gas three-phase mixing centrifugal extraction separators in series via pipelines to form a structure as follows: Figure 6 The three-stage countercurrent extraction system is shown below. For ease of identification, the stages are arranged as follows: Figure 6 The separators shown are named first separator A, second separator B, and third separator C, respectively. The first separator A receives the loaded organic phase at its material inlet N6 and outputs lithium bicarbonate solution at its heavy phase outlet N2. The light phase outlet N3 of the first separator A is connected to the material inlet N6 of the second separator B, and the extractant inlet N7 of the first separator A is connected to the heavy phase outlet N2 of the second separator B. The light phase outlet N3 of the second separator B is connected to the material inlet N6 of the third separator C, and the extractant inlet N7 of the second separator B is connected to the heavy phase outlet N2 of the third separator C. The light phase outlet N3 of the third separator C outputs the delithiated organic phase, and the extractant inlet N7 of the third separator C receives pure water. All gas inlets N5 are connected to an external gas source, preferably carbon dioxide, but other gas sources can also be considered.

[0033] Taking a retired battery black powder as an example, the feed solution contains more than 1.5 g / L of Li and more than 60 g / L of Na. Countercurrent back-extraction is performed using a centrifugal extraction separator consisting of 2-5 stages of countercurrent extraction, 1-3 stages of countercurrent washing, and 2-4 stages of liquid-liquid-gas three-phase mixing. The oil-water ratio in the extraction stage is 1:0.5-4:1; in the washing stage, it is 2:1-12:1; and in the back-extraction stage, it is 1:1-12:1. Carbon dioxide is input at 2-5 times the total feed volume. After centrifugal extraction, the back-extraction solution contains more than 20 g / L of Li and less than 10 g / L of Na, with a recovery rate generally exceeding 90%. The lithium bicarbonate solution obtained from back-extraction undergoes a pyrolysis process to obtain crude lithium carbonate. Subsequent washing and purification processes can then be used to prepare battery-grade lithium carbonate.

[0034] Using the device described above, a recycling project with an annual processing capacity of 50,000 tons or more of retired batteries can be realized.

[0035] Of course, those skilled in the art will recognize that the present invention is not limited to the details of the exemplary embodiments described above, but also includes the same or similar methods that can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description.

[0036] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0037] All technical parts not described in detail in this invention are publicly known technologies.

Claims

1. A liquid-liquid-gas three-phase mixing centrifugal extraction separator, comprising a housing (10) and a drum (20) arranged coaxially, wherein a heavy phase outlet N2 and a light phase outlet N3 are arranged at the housing (10); characterized in that: The drum (20) is a barrel-shaped structure with its opening facing upwards. The bottom of the outer barrel of the drum (20) and the bottom of the inner cavity of the shell (10) enclose a secondary mixing chamber (a). A dispersion disk (21) is coaxially arranged at the bottom of the outer barrel of the drum (20), and a flow channel hole (22) communicating with the inner cavity of the drum (20) is passed through the bottom of the outer barrel. A bottom cylinder (31) is also coaxially arranged at the bottom surface of the shell (10). A dispersion cylinder (32) is coaxially sleeved inside the bottom cylinder (31). The cavity of the dispersion cylinder (32) forms a primary mixing chamber communicating with the secondary mixing chamber (a). (b) A lifting paddle (33) is coaxially installed inside the dispersion cylinder (32), and the lifting paddle (33) is fixed at the drum (20); the inner wall of the bottom cylinder (31) and the outer wall of the dispersion cylinder (32) form an air inlet chamber, which is connected to the gas inlet N40, and an aeration hole is provided on the cylinder wall of the dispersion cylinder (32) to connect the air inlet chamber and the primary mixing chamber (b); a liquid phase feed chamber (d) connected to the primary mixing chamber (b) is also fixedly connected below the bottom cylinder (31), and a material inlet N6 and an extractant inlet N7 are arranged at the liquid phase feed chamber (d).

2. The liquid-liquid-gas three-phase mixing centrifugal extraction separator according to claim 1, characterized in that: The space above the barrel opening of the drum (20) forms a gas collection chamber (c), and a gas outlet N1 is arranged at the top of the gas collection chamber (c); the centrifugal extraction separator also includes a venturi tube (40); the inlet of the venturi tube (40) constitutes a gas external interface N5, the outlet constitutes a gas internal inlet N40, and the negative pressure inlet N4 of the venturi tube (40) is connected to the gas outlet N1 via a return gas pipeline (60).

3. The liquid-liquid-gas three-phase mixing centrifugal extraction separator according to claim 2, characterized in that: The dispersion disk (21) includes a chassis and circumferentially distributed arc blades (23) on the chassis. The flow channel holes (22) are arranged on the chassis surface between the near-axial end of the arc blades (23) and the axis of the drum (20), and each flow channel hole (22) is opened on the same pitch circle of the chassis.

4. The liquid-liquid-gas three-phase mixing centrifugal extraction separator according to claim 3, characterized in that: The chassis forms the bottom of the drum (20) and is coaxially fixed to the bottom flange (24) of the drum (20); a mating ring (11) is provided in the inner cavity of the housing (10), and the outer edge of the bottom flange (24) overlaps the ring (11) from top to bottom, and the two form a dynamic and static sealing fit through the sealing assembly (50).

5. The liquid-liquid-gas three-phase mixing centrifugal extraction separator according to claim 4, characterized in that: The sealing assembly (50) is a labyrinth seal, a stepped seal, or an embedded spiral seal.

6. The liquid-liquid-gas three-phase mixing centrifugal extraction separator according to any one of claims 3-5, characterized in that: The curvature of each arc blade (23) is opposite to that of the drum (20), and the height of the far-axis end of the arc blade (23) is higher than that of the near-axis end, so that the unfolded shape of the arc blade (23) presents a trapezoidal structure.

7. The liquid-liquid-gas three-phase mixing centrifugal extraction separator according to claim 6, characterized in that: A dispersion hole (23a) is provided through the blade surface at the far-axis end of the arc-shaped blade (23).

8. The liquid-liquid-gas three-phase mixing centrifugal extraction separator according to any one of claims 2-5, characterized in that: Pressure gauges are installed at both the return gas pipeline (60) and the external gas interface N5; the material inlet N6 and the extractant inlet N7 are symmetrically arranged along the axis of the liquid phase feed chamber (d), and the vent N8 is located at the bottom of the liquid phase feed chamber (d).

9. A gas reverse extraction centrifugation system, characterized in that: This includes three sets of liquid-liquid-gas three-phase mixing centrifugal extraction separators as described in any one of claims 2-5, which are here named, in sequence, the first separator (A), the second separator (B), and the third separator (C), wherein: The first separator (A) inputs the loaded organic phase at the material inlet N6 and outputs lithium bicarbonate solution at the heavy phase outlet N2; the light phase outlet N3 of the first separator (A) is connected to the material inlet N6 of the second separator (B), and the extractant inlet N7 of the first separator (A) is connected to the heavy phase outlet N2 of the second separator (B). The light phase outlet N3 of the second separator (B) is connected to the material inlet N6 of the third separator (C), and the extractant inlet N7 of the second separator (B) is connected to the heavy phase outlet N2 of the third separator (C). The light phase outlet N3 of the third separator (C) outputs the delithiated organic phase, and the extractant inlet N7 of the third separator (C) inputs pure water; All gas external interfaces N5 are connected to an external gas source.

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