A method for wet recovery treatment of waste batteries

Abstract

This invention relates to the field of battery recycling, specifically a wet recycling method for waste batteries, comprising the following steps: S1, pre-crushing the battery pack to separate black powder; S2, acid leaching to remove slag from the black powder; the resulting lithium precipitation mother liquor enters a centrifugal extraction process for lithium extraction; the resulting filter residue is transported to a process-controlled air-blown unloading filter for further solidification, and the resulting lithium precipitation mother liquor enters a centrifugal extraction process for lithium extraction; S3, the lithium precipitation mother liquor from S2 is collected and centrifuged for lithium extraction. This invention achieves efficient recycling of waste batteries.

Description

Technical Field

[0001] This invention relates to the field of battery recycling, specifically a wet recycling method for waste batteries. Background Technology

[0002] Lithium-ion batteries for new energy vehicles have a limited lifespan. After being reused through a tiered system, retired lithium-ion batteries need to undergo recycling to separate and purify valuable elements in the cathode material, allowing them to re-enter the lithium battery material manufacturing process and achieve the circular utilization of energy metals. Lithium-ion batteries for new energy vehicles are mainly divided into lithium iron phosphate, ternary lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide battery systems. Retired lithium-ion batteries contain abundant valuable metals, including cobalt, nickel, manganese, lithium, copper, aluminum, and graphite. Taking NCM cathode materials as an example, the average content of some metals is significantly higher than the average grade of corresponding primary ores in China (lithium: 2%-5% > 2.75%, nickel: 5%-12% > 2%, cobalt: 5%-20% > 1.5%). These metals have extremely high recycling value, and compared to primary resources, their separation process is simpler, the regeneration process consumes less energy, and has less environmental impact. Therefore, with the increasing volume of retired batteries each year, how to recycle waste batteries, especially the efficient recycling of lithium ions, has become an urgent technical problem to be solved. Summary of the Invention

[0003] To avoid and overcome the technical problems existing in the prior art, this invention provides a wet recycling method for waste batteries. This invention achieves efficient recycling and utilization of waste batteries.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A wet recycling method for waste batteries includes the following steps: Includes the following steps: S1. The battery pack is pre-crushed to separate out the black powder; S2. Acid leaching is performed on the black powder to remove slag. The lithium precipitation mother liquor obtained after treatment is then introduced into the lithium precipitation mother liquor centrifugal extraction lithium extraction process. The filter residue obtained after processing is transported to a process-controlled air-blown unloading filter for further solidification treatment, and the resulting lithium mother liquor enters the lithium precipitation mother liquor centrifugal extraction lithium extraction process. S3. Collect the lithium-precipitated mother liquor from S2 and extract lithium by centrifugation. S31. Adjust the pH of the lithium precipitation mother liquor to 12.5-13.5 with alkaline solution to obtain the prepared solution; S32. The prepared liquid and the organic extractant are subjected to countercurrent contact in a centrifugal extractor with 2 to 5 stages connected in series at an oil-water volume ratio of 1:2 to 5:1 to separate the lithium-loaded organic phase and the raffinate. S33. The lithium-loaded organic phase and the detergent are subjected to countercurrent contact in a centrifugal extractor with 2 to 5 stages connected in series at a water-oil volume ratio of 1:10 to 1:1 to separate the washed organic phase and the washing liquid containing impurities. S34. The washed organic phase is mixed and contacted with the back-extraction agent to separate the lithium-rich aqueous phase and the empty organic phase. S35. The empty organic phase and the washing water are contacted in a centrifugal extractor at a water-oil volume ratio of 1:3 to 3:1 to separate the regenerated organic extractant and acidic wastewater.

[0005] As a further aspect of the present invention: the volumetric flow rate ratio of the back-extraction agent to the washed organic phase is 1:10 to 1:1; the alkaline solution is a sodium hydroxide solution; the lithium concentration of the lithium precipitation mother liquor is 1 to 5 g / L; the organic extractant includes a mixture of β-diketone extractants and sulfonated kerosene; the back-extraction agent is a 1 to 5 mol / L sulfuric acid solution, or pure water or tap water with continuously introduced carbon dioxide gas. When carbon dioxide aerated water is used as the back-extraction agent, the back-extraction is carried out in a stirred back-extraction tower or centrifugal extractor equipped with a gas distributor, and CO2 is continuously introduced.

[0006] As a further embodiment of the present invention: S3 employs an extraction unit for liquid-liquid extraction, a washing section unit for washing the loaded organic phase, and a back-extraction unit for back-extraction and extractant regeneration. The extraction unit includes a material pipeline, a raffinate pipeline, a material storage tank, a material booster pump, an extractant pipeline, an extractant storage tank, an extractant booster pump, and a multi-stage centrifugal extractor. The material pipeline is sequentially connected to the material storage tank, the material booster pump, the aqueous phase inlet of the first stage centrifugal extractor, the aqueous phase outlet of the first stage centrifugal extractor, the aqueous phase inlet of the first stage centrifugal extractor, the aqueous phase outlet of the first stage centrifugal extractor, ... the aqueous phase inlet of the first stage centrifugal extractor, the aqueous phase outlet of the first stage centrifugal extractor, and finally connected to the raffinate pipeline. The extractant pipeline is sequentially connected to the extractant storage tank, the extractant booster pump, the organic phase inlet of the first stage centrifugal extractor, the organic phase outlet of the first stage centrifugal extractor, the organic phase inlet of the second stage centrifugal extractor, the organic phase outlet of the second stage centrifugal extractor, ... the organic phase inlet of the first stage centrifugal extractor and the organic phase outlet of the first stage centrifugal extractor, and finally discharged to the washing section unit.

[0007] As a further embodiment of the present invention: In the acid leaching and slag removal process of S2, at least two sets of leaching tanks are included. Compressed air pipelines, black powder pipelines, hydrogen peroxide pipelines, concentrated sulfuric acid pipelines, and water supply pipelines supply materials to each leaching tank, and the black powder is dissolved in the leaching tank. The material discharged from the leaching tank is successively transported to the reaction washing clarification and thickening machine after passing through the slurry transfer tank and the slurry pump. After the reaction washing clarification and thickening machine processes and separates the material, the mother liquor is transported to the belt-type material transfer tank, and the filter residue is transported to the process-controlled air-blowing unloading filter. After the filter residue is further processed by the process-controlled air-blowing unloading filter, the recovered mother liquor enters the material pipeline of the lithium precipitation mother liquor centrifugal extraction lithium extraction process. The mother liquor entering the belt-type transfer tank passes sequentially through the transfer tank centrifugal pump, the belt-type storage tank, and the storage tank centrifugal pump before entering the material pipeline for the lithium extraction process of the lithium precipitation mother liquor centrifugal extraction.

[0008] As a further embodiment of the present invention: the compressed air pipeline and the water supply pipeline are split and then supplied with compressed air and water to the reaction washing clarification and concentration machine.

[0009] As a further embodiment of the present invention: the process-controlled air-blowing unloading filter includes a liquid collection chamber for containing filtrate, an inverted U-shaped tube is provided outside the liquid collection chamber, a mother liquor outlet 1 extending to the outside is formed at the lowest liquid level of the liquid collection chamber, one end of the inverted U-shaped tube is connected to the mother liquor outlet 1 through a variable length tube structure, and the other end of the inverted U-shaped tube is the mother liquor outlet 2. A lifting adjustment device is also provided outside the liquid collection chamber for driving the inverted U-shaped tube to move vertically back and forth to control the height difference between the mother liquor outlet 2 and the lowest liquid level.

[0010] As a further embodiment of the present invention: the variable length tube structure includes a connecting pipe vertically installed on the mother liquor outlet, and the connecting end of the inverted U-shaped tube is slidably sleeved inside the connecting pipe through a sealing seat.

[0011] As a further embodiment of the present invention: the lifting and adjusting device is a pneumatic lifting device, and the air source interface of the pneumatic lifting device is connected to or disconnected from the air source vehicle through a pipeline with a control valve of the adjusting device; a conical ring for settling particles using the principle of inclined plate sedimentation is provided in the liquid accumulation chamber.

[0012] As a further embodiment of the present invention: a filter plate is installed inside the tank of the reaction washing clarification and concentration machine. The filter plate divides the tank cavity into an upper working chamber and a lower mother liquor chamber. The stirring shaft extends from the working chamber through the liquid seal seat to the outside of the tank and is coaxially fixed with the motor shaft of the stirring motor. A lifting system is installed on the tank to drive the stirring motor and the stirring shaft to perform lifting and lowering actions. A mother liquor discharge pipe communicating with the mother liquor chamber is provided at the bottom of the tank. The tank also includes a liquid seal seat installed at the top of the tank. The liquid seal seat has a sleeve-shaped structure with an open top. An insertion hole for the stirring shaft to pass through is opened at the bottom of the liquid seal seat. The diameter of the insertion hole is larger than the diameter of the stirring shaft. The liquid seal seat includes an outer baffle and an inner baffle arranged coaxially. There is a liquid seal ring cavity between the inner baffle and the outer baffle for the injection of sealing medium. A liquid seal barrel with an open bottom is coaxially fixed on the stirring shaft. The opening of the liquid seal barrel is inserted downward into the liquid seal ring cavity, and the opening of the liquid seal barrel is below the liquid surface of the liquid seal ring cavity.

[0013] As a further embodiment of the present invention: the replenishment pipe draws the medium from the tank and replenishes it into the liquid seal ring cavity. The liquid seal seat is also equipped with a level gauge to measure the liquid level in the liquid seal ring cavity. While the stirring shaft moves up and down in the vertical direction, the replenishment pipe replenishes the medium into the liquid seal ring cavity, so that the opening of the liquid seal tank is always below the liquid level in the liquid seal ring cavity.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention obtains black powder raw material from crushed batteries, and after acid leaching and recovery treatment of the black powder raw material, lithium precipitation mother liquor is obtained. A multi-stage centrifugal extractor is used for countercurrent extraction, washing, back-extraction, and organic phase regeneration, achieving the goal of recovering lithium from the complex mother liquor and realizing the efficient recycling of waste batteries. The entire process is continuous and automated, the extractant is recycled, energy and reagent consumption is low, the equipment is compact and has a large processing capacity; the process is closed and safe, and the amount of waste generated is small. Overall, this invention provides an advanced process route for the recycling of waste batteries and the resource utilization of lithium precipitate mother liquor, characterized by high recovery rate, high product purity, low operating cost, and environmental friendliness. The lithium extraction system for lithium precipitate mother liquor centrifugal extraction integrates back-extraction and washing functions into the same centrifugal extractor. The extractant regeneration for impurity cleaning is simultaneously achieved during the CO2 aqueous solution back-extraction process, reducing the number of devices required. It does not use strong acids and does not generate acidic wastewater; instead, it utilizes CO2 water back-extraction to generate LiHCO3. The CO2 released during thermal decomposition can be recycled, achieving a closed-loop CO2-lithium system with no acidic wastewater discharge. The system's robustness is significantly enhanced. Precise CO2 circulation is achieved through a carbon dioxide recovery pipe and a tail gas treatment pipe, avoiding gas waste. Furthermore, backup pipes support uninterrupted production during equipment maintenance, improving continuous operation stability. The back-extraction product, LiHCO3, can be directly pyrolyzed to obtain electronic-grade Li2CO3, eliminating the need for sodium carbonate synthesis.

[0015] 2. The reaction washing clarification and thickening machine of this invention combines reaction, washing, clarification, and filtration functions. Its unique double-S blade design on the stirring shaft ensures mixing intensity while reducing energy consumption, achieving energy savings. The C-shaped design of its material inlet pipe prevents material from impacting the bottom filter plate during feeding, thus avoiding potential hazards. A radar level gauge monitors the liquid level in the tank in real time. By installing a sight glass on the tank in conjunction with the radar level gauge, dual monitoring of the slurry level can be achieved. Any material leaking from the tank during operation can be controlled by inserting a... After passing through the annular gap between the inlet and the stirring shaft, the medium is blocked by the liquid seal ring and enters the liquid seal ring cavity, where it mixes with the medium inside to achieve a liquid seal effect. This avoids friction between the main shaft and the material during high-speed rotation, reducing the danger during the production of sensitive materials. After the replenishment pipe is inserted into the liquid seal ring cavity, the liquid level in the liquid seal ring cavity is measured according to the level gauge, and the medium in the tank is drawn and injected into the liquid seal ring cavity. During the lifting and lowering of the stirring shaft, the liquid level of the medium in the liquid seal ring cavity is always higher than the height of the opening of the liquid seal tank, ensuring the reliability of the seal.

[0016] 3. The process-controlled air-blowing unloading filter of the present invention can achieve precise control of the entire filtration process by adjusting the height difference of the inverted U-shaped tube in real time. Specifically, it is manifested in the following ways: reducing the filtration driving force during the feeding stage can effectively prevent fine particles from impacting and embedding deep into the filter media under high pressure differential, thereby forming an initial filter cake layer with uniform structure and good pore permeability, laying the structural foundation for subsequent high-efficiency filtration; reducing the filtrate flow rate during the washing stage can prolong the penetration and diffusion time of the washing liquid in the filter cake, significantly improving mass transfer efficiency and displacement effect, and improving the final purity of the product while reducing washing liquid consumption; increasing the filtration driving force during the pressing and drying stage can strengthen the extrusion and removal of residual liquid phase in the filter cake, effectively reducing the final moisture content of the filter cake, thereby reducing the energy load of the subsequent drying process and improving the overall product yield.

[0017] 4. The centrifugal separation device of the present invention pumps liquid into the premixing chamber through a centripetal impeller. This pumping process is accompanied by strong shearing and entrainment, which completes the first discretization and preliminary mixing of the heavy phase and the light phase. Subsequently, the material entering from the bottom center of the premixing chamber is immediately captured by the conical mixing impeller and undergoes a second high-intensity mixing. The present invention, through a dedicated premixing chamber set at the front end of the drum, completes two-stage progressive mixing in a compact and relatively closed high-intensity shear field before the material enters the main drum, which greatly improves the mass transfer surface area and mixing uniformity, creating excellent conditions for subsequent efficient extraction reactions. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the process flow for acid leaching and slag removal in this invention.

[0019] Figure 2This is a schematic diagram of the process flow for lithium extraction from lithium mother liquor by centrifugation according to the present invention.

[0020] Figure 3 for Figure 2 Schematic diagram of the structure of a centrifugal separation device; Figure 4 for Figure 3 A magnified view of part A in the image; Figure 5 for Figure 3 A magnified view of part B in the image; Figure 6 for Figure 3 Longitudinal section of the middle guide flow cavity; Figure 7 for Figure 3 Top view of the central guide flow cavity.

[0021] Figure 8 This is a schematic diagram of the reaction washing clarification and concentration machine in this invention.

[0022] Figure 9 for Figure 8 Enlarged view of point C in the middle.

[0023] Figure 10 This is a schematic diagram of the process flow for the battery breakage pretreatment of the present invention.

[0024] Figure 11 This is a schematic diagram of the inverted U-shaped tube of the process-controlled air-blown unloading filter in this invention, with the tube positioned at a low position. Figure 12 This is a schematic diagram of the inverted U-shaped tube of the process-controlled air-blown unloading filter in this invention, with the tube positioned at a high position. Figure 13 This is a three-dimensional structural diagram of the 12-blade component shown in the figure.

[0025] In the picture: A1, Reaction washing, clarification and concentration machine; A01, Tank body; A11, Liquid seal seat; 11A. Outer baffle; 11B. Inner baffle; 11C, Insertion hole; 11D, Liquid seal ring cavity; 11F, Liquid replenishment pipe; 11G, Liquid level gauge; A2, stirring motor; A21, stirring shaft; A22, impeller; A23, liquid seal tank; A231, Liquid seal ring; A232, Liquid separator plate; A233, Locking bolt; A3. Lifting system; A4. Material inlet pipe; A5. Washing spray ball; A6, Slurry suction pipe; A7, Filter plate; A8, Mother liquor discharge pipe.

[0026] 100. Centrifugal separation equipment; 200. Centrifugal effluent kinetic energy recovery device; 300. Feeding device; 101. Frame; 102. Drive motor; 103. Outer shell; 104. Rotating shaft; 105. Rotary drum; 105A. Conical widening section; 106. Heavy phase weir plate; 107. Light phase weir plate; 108. Heavy phase collection chamber; 109. Light phase collection chamber; 110. Heavy phase outlet; 111. Light phase outlet; 112. Guide hole; 113. Heavy phase inlet; 114. Light phase inlet; 115. Feed impeller; 201. Outlet cavity; 202. Nozzle; 203. Head; 203A. Inclined surface; 204. Impact baffle; 205. Guide vane; 301. Premixing chamber; 302. Spiral impeller; 303. Mixing impeller; 304. Enhanced mixing impeller; 305. Mixing baffle plate; 306. Screw feeder; 307. Press impeller; 401. Material pipeline; 402. Raffinate pipeline; 403. Material storage tank; 404. Material booster pump; 405. Extractant pipeline; 406. Extractant storage tank; 407. Extractant booster pump; 408. Centrifugal extractor (one); 409. Washing pipe; 410. Detergent pipe; 411. Detergent storage tank; 412. Detergent booster pump; 413. Centrifugal extractor II; 414. Back-extraction inlet pipe; 415. Carbon dioxide inlet pipe; 416. Pure water inlet pipe; 417. Homogenizer pump; 418. Centrifugal extractor III; 419. Mixture pipeline; 420. Mixture booster pump; 421. Carbon dioxide reactor; 422. Cleaning agent pipeline; 423. Residual liquid drain pipe; 424. Exhaust gas treatment pipeline; 425. Refill pipeline; 426. Backup pipeline; 427. Carbon dioxide recovery pipeline.

[0027] 1. Blade assembly; 10. Pneumatic control box; 11. Rotary joint; 12. Main shaft; 13. Side shaft; 14. Blade support; 15. Air nozzle; 2. Drive unit; 3. Cylinder body; 30. Top cover plate; 31. Conical cylinder; 32. Conical filter disc; 33. Liquid collection chamber; 34. Conical ring; 35. Shell; 36. Opening area; 37. Annular opening; 40. Lifting and adjusting device; 41. Inverted U-shaped tube; 42. Sealing seat; 43. Connecting pipe; 51. Main air valve; 52. Regulating device control valve; 53. Filter press inlet valve; 54. Gas control valve; 55. Feed control valve; 56. Exhaust control valve; 57. Mother liquor U-tube discharge valve; 58. Mother liquor discharge valve; 59. Backflush air inlet valve; 510. Automatic slag discharge valve; 61. Feed inlet; 62. Air inlet; 63. Exhaust outlet; 64. Mother liquor outlet 2; 65. Mother liquor outlet 1; 66. Slag discharge port.

[0028] 701. Compressed air pipeline; 702. Black powder pipeline; 703. Hydrogen peroxide pipeline; 704. Concentrated sulfuric acid pipeline; 705. Water supply pipeline; 706. Leaching tank; 707. Pulping transfer tank; 708. Mortar pump; 709. Belt conveyor transfer tank; 710. Transfer tank centrifugal pump; 711. Belt-type liquid storage tank; 712. Storage tank centrifugal pump; 713. Solid slag deep treatment pipeline; 801. Crusher; 802. Screw conveyor; 803. Material collector; 804. Air classifier; 805. Diaphragm collection box; 806. Black powder conveyor; 807. Belt conveyor; 808. Magnetic material collection pipeline; 809. Crusher; 810. Pulse dust collector; 811. Exhaust fan; 812. Diaphragm debris collection pipeline. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Please see Figures 1-13 In this embodiment of the invention, a wet recycling method for waste batteries includes the following steps: S1. The battery pack is pre-crushed to separate out the black powder; S2. Acid leaching is performed on the black powder to remove slag. The lithium precipitation mother liquor obtained after treatment is then introduced into the lithium precipitation mother liquor centrifugal extraction lithium extraction process. The filter residue obtained after processing is transported to a process-controlled air-blown unloading filter for further solidification treatment, and the resulting lithium precipitation mother liquor enters the lithium precipitation mother liquor centrifugal extraction lithium extraction process. S3. Collect the lithium-precipitated mother liquor from S2 and extract lithium by centrifugation.

[0031] The pre-crushing process of S1: such as Figure 10 As shown, the battery pack enters the crusher 801 for crushing. The resulting ultrafine powder mixture enters the collector 803, while the coarse material containing black powder enters the screw conveyor 802 and is conveyed to the air classifier 804. The ultrafine dust outlet of the air classifier 804 is connected to the collector 803. The ultrafine powder received in the collector 803 is mixed and then enters the diaphragm collection box 805. The diaphragm fragments separated from the light material outlet of the air classifier 804 also enter the diaphragm collection box 805. After the diaphragm fragments are filtered out by the diaphragm collection box 805, they are collected through the diaphragm fragment collection pipe 812. The remaining powder in the diaphragm collection box 805 is sucked out and collected by the negative pressure of the induced draft fan 811 of the pulse dust collector 810. The pulse dust collector 810 can provide negative pressure suction for the entire closed system simultaneously. The secondary outlet of the air classifier 804 is used to screen out black powder, which is then conveyed by the black powder conveyor 806 to the next process for acid leaching and slag removal. After collecting magnetic materials at the heaviest outlet of the air classifier 804, the remaining material enters the pulverizer 809 for pulverization.

[0032] The acid leaching and slag removal process in S2: such as Figure 1 As shown, the system includes at least two leaching tanks 706, with compressed air pipeline 701, black powder pipeline 702, hydrogen peroxide pipeline 703, concentrated sulfuric acid pipeline 704, and water supply pipeline 705 supplying materials to each leaching tank 706. After being split, the compressed air pipeline 701 and water supply pipeline 705 also simultaneously supply water and air to the reaction washing clarification concentrator A1.

[0033] After the black powder enters the leaching tank 706, it dissolves. The output of the leaching tank 706 passes through the slurry transfer tank 707 and the slurry pump 708 in sequence, and is then transported to the reaction washing clarification and thickening machine A1. After the reaction washing clarification and thickening machine A1 processes and separates the material, the mother liquor is transported to the belt feed transfer tank 709, and the filter residue is transported to the process-controlled air-blowing unloading filter. After the process-controlled air-blowing unloading filter further processes the filter residue, the recovered mother liquor enters the material pipeline 401 of the lithium precipitation mother liquor centrifugal extraction lithium extraction process. The mother liquor entering the belt-type transfer tank 709 passes sequentially through the transfer tank centrifugal pump 710, the belt-type storage tank 711, and the storage tank centrifugal pump 712 before entering the material pipeline 401 for the lithium extraction process of the lithium mother liquor centrifugal extraction.

[0034] The centrifugal extraction process of lithium precipitation mother liquor in S3: such as Figure 2The process includes the following steps: S1, adjusting the pH of the lithium precipitation mother liquor to 12.5–13.5 with alkaline solution to obtain a prepared solution; S2, subjecting the prepared solution and an organic extractant to countercurrent contact in a 2–5 stage series centrifugal extractor at an oil-water volume ratio of 1:2–5:1 (i.e., countercurrent contact within the range of an oil-water volume ratio of 1:2 to 5:1), separating the lithium-loaded organic phase and raffinate; S3, subjecting the lithium-loaded organic phase and a detergent to a 2–5 stage series centrifugal extractor at a water-oil volume ratio of 1: S10–1:1 countercurrent contact (i.e., countercurrent contact within the range of water-oil volume ratio 1:10 to 1:1) to separate the washed organic phase and the washing liquid containing impurities; S4, the washed organic phase is mixed and contacted with the back-extraction agent to separate the lithium-rich aqueous phase and the empty organic phase; S5, the empty organic phase is contacted with the washing water in a centrifugal extractor at a water-oil volume ratio of 1:3–3:1 (contact within the range of water-oil volume ratio 1:3 to 3:1) to separate the regenerated organic extractant and acidic wastewater.

[0035] According to one embodiment of the present invention, in step S4, the volume flow ratio of the back-extraction agent to the washed organic phase is 1:10–1:1 (the volume flow ratio is in the range of 1:10 to 1:1).

[0036] According to one embodiment of the present invention, the alkaline solution is a sodium hydroxide solution; the lithium concentration of the lithium precipitation mother liquor is 1–5 g / L; the organic extractant comprises a mixture of β-diketone extractants and sulfonated kerosene; the back-extraction agent is a 1–5 mol / L sulfuric acid solution, or pure water or tap water with continuously introduced carbon dioxide gas. When carbon dioxide aerated water is used as the back-extraction agent, the back-extraction is carried out in a stirred back-extraction tower or centrifugal extractor equipped with a gas distributor, and CO2 is continuously introduced.

[0037] According to one embodiment of the present invention, the method is implemented using a lithium extraction system based on centrifugal extraction of lithium mother liquor. The system includes an extraction unit for liquid-liquid extraction, a washing section unit for washing the loaded organic phase, and a back-extraction unit for back-extraction and extractant regeneration. The equipment performing centrifugal extraction in the extraction unit, washing section unit, and back-extraction unit is the same equipment.

[0038] The extraction unit includes a material pipeline 401, a raffinate pipeline 402, a material storage tank 403, a material booster pump 404, an extractant pipeline 405, an extractant storage tank 406, an extractant booster pump 407, and a multi-stage centrifugal extractor 408, which is the same equipment as this unit. The material pipeline 401 is connected in sequence to the material storage tank 403 and the material booster pump 404, and then connected in series with the water phase inlet and outlet of the first-stage to N-stage centrifugal extractor 408, finally flowing into the raffinate pipeline 402. The extractant pipeline 405 is connected in sequence to the extractant storage tank 406 and the extractant booster pump 407, and then connected in series with the organic phase inlet and outlet of the first-stage to N-stage centrifugal extractor 408, finally discharging into the washing section unit.

[0039] According to one embodiment of the present invention, the washing section unit includes a washing pipe 409, a detergent pipe 410, a detergent storage tank 411, a detergent booster pump 412, and a multi-stage centrifugal extractor 413, which is the same equipment as the washing section unit. The detergent pipe 410 is connected in sequence to the detergent storage tank 411 and the detergent booster pump 412, and then connected in series with the water phase inlet and outlet of the first to Nth stage centrifugal extractors 413, finally flowing into the washing residue pipe. One end of the washing pipe 409 is connected to the discharge end of the extractant pipe 405, and the other end is connected in series with the organic phase inlet and outlet of the first to Nth stage centrifugal extractors 413, finally discharging into the back-extraction unit.

[0040] According to one embodiment of the present invention, the back-extraction unit includes a back-extraction inlet pipe 414, a carbon dioxide inlet pipe 415, a pure water inlet pipe 416, a homogenizing pump 417, a centrifugal extractor 418, a mixed liquor pipeline 419, a mixed liquor booster pump 420, and multiple carbon dioxide reactors 421. The centrifugal extractor 418 is the same equipment as this unit. The carbon dioxide inlet pipe 415 and the pure water inlet pipe 416 are combined and connected in parallel to each carbon dioxide reactor 421 through a pipeline equipped with a homogenizing pump 417. Each carbon dioxide reactor 421 is equipped with a... A stirrer and a gas distributor are included. One end of the back-extraction inlet pipe 414 is connected to the discharge end of the washing pipe 409, and the other end of the back-extraction inlet pipe 414 is connected in parallel to each carbon dioxide reactor 421. The outlet of each carbon dioxide reactor 421 is connected to the inlet of the centrifugal extractor 418 through a mixed liquid pipeline 419 equipped with a mixed liquid booster pump 420. The aqueous phase outlet of the centrifugal extractor 418 is connected to the lithium bicarbonate product pipeline, and the organic phase outlet of the centrifugal extractor 418 is connected to the extractant storage tank 406 through an unloaded organic phase return pipe.

[0041] According to one embodiment of the present invention, the system further includes a cleaning agent pipeline 422, a residual liquid drain pipe 423, a carbon dioxide recovery pipe 427, and a tail gas treatment pipeline 424; the top ends of each centrifugal extractor 1 408, each centrifugal extractor 2 413, and each centrifugal extractor 3 418 are connected to the cleaning agent pipeline 422, and the drain ports at both ends of each centrifugal extractor 1 408, each centrifugal extractor 2 413, and each centrifugal extractor 3 418 are connected to the residual liquid drain pipe 423, and the top end of each carbon dioxide reactor 421 is connected to the carbon dioxide recovery pipe 427.

[0042] According to one embodiment of the present invention, the top ends of each centrifugal extractor 1 408, each centrifugal extractor 2 413 and each centrifugal extractor 3 418 are connected to the exhaust gas treatment pipe 424.

[0043] According to one embodiment of the present invention, it further includes a supplement pipe 425 and a spare pipe 426; the supplement pipe 425 is connected in parallel to the organic phase inlet of each centrifugal extractor 408; a spare pipe 426 is provided at the parallel connection of the extractant pipe 405, the material pipe 401, the washing pipe 409, and the washing pipe 410 so as to skip the machine being repaired or maintained when the centrifugal extractor 408 or the centrifugal extractor 413 is being repaired or maintained.

[0044] The working process of this system is as follows: The lithium precipitation mother liquor passes through the material storage tank 403 → material booster pump 404 → centrifugal extractor 408 aqueous phase inlet, and comes into contact with the organic phase from the extractant storage tank 406 via the extractant booster pump 407 → centrifugal extractor 408 organic phase inlet. The aqueous phase of the extract is then discharged through the centrifugal extractor 408 aqueous phase outlet → raffinate pipeline 402; the loaded organic phase passes through the centrifugal extractor 408 organic phase outlet → washing pipeline 409 → back-extraction inlet 414 → carbon dioxide reactor 421. Simultaneously, the CO2 aqueous solution flows through carbon dioxide inlet pipe 415 + pure water inlet pipe 416 → homogenizer pump 417 → carbon dioxide reactor 421. In the carbon dioxide reactor 421, the CO2 aqueous solution simultaneously achieves lithium back-extraction to generate LiHCO3 and organic phase cleaning. The lithium-rich aqueous phase flows through mixed liquid pipeline 419 → mixed liquid booster pump 420 → centrifugal extractor 3 418 → lithium bicarbonate product pipeline. The regenerated organic phase flows through centrifugal extractor 3 418 → empty organic phase return pipe back to extractant storage tank 406. The N-stage in this system is 3 stages.

[0045] like Figures 2 to 6As shown, centrifugal extractor 1 (408), centrifugal extractor 2 (413), and centrifugal extractor 3 (418) are the same equipment (referring to multi-stage series units with identical structure and function, used for continuous countercurrent extraction). This equipment includes a centrifugal separator 100 (core separator), a centrifugal liquid kinetic energy recovery device 200 (a rotating component used to recover liquid kinetic energy and convert it into auxiliary driving force) located at the heavy phase outlet 110 of the centrifugal separator 100, and a feeding device 300 (a pre-module used for material premixing and stable feeding) located at the inlet of the centrifugal separator 100. The centrifugal separator 100 includes a frame 101 (support frame, usually made of welded metal structure) and a drive motor 102 (main drive unit) mounted on the frame 101. An outer shell 103 (equipment outer cylinder, generally a metal shell) is fixedly installed inside the frame 101. A rotating drum 105 (high-speed rotating separation chamber, usually made of stainless steel) is rotatably mounted on a rotating shaft 104. The working end of the drive motor 102 is connected to the rotating shaft 104 via a drive (power is transmitted through a coupling or belt). Heavy phase inlet 113 and light phase inlet 114 (two-phase material input interface) are respectively provided on the bottom sides of the outer shell 103. From top to bottom, heavy phase weir plate 106 and light phase weir plate 107 (adjustable overflow weir ring, used to control the height of the two-phase separation interface) are arranged sequentially on the top inner wall of the rotating drum 105. A heavy phase collection chamber 108 (high-density phase temporary storage area) is formed above the heavy phase weir plate 106, and a light phase collection chamber 109 (low-density phase temporary storage area) is formed above the light phase weir plate 107. A heavy phase outlet 110 (heavy phase discharge channel) is formed on the heavy phase collection chamber 108, and a light phase outlet 111 (light phase discharge channel) is formed on the light phase collection chamber 109. The centrifugal effluent kinetic energy recovery device 200 includes multiple outlet chambers 201 (rotary kinetic energy recovery units, typically 4–8 in number) evenly arranged circumferentially on and synchronously rotating with the heavy phase weir plate 106. The outlet chambers 201 are divided into a double-layer structure (forming inner and outer flow channels) by impact baffles 204, thus creating a C-shaped path for the fluid inside the outlet chamber (the fluid first flows downward along the inner wall, then reverses and flows upward along the outer wall). The outlet of the C-shaped path forms a nozzle 202 for ejecting fluid in the opposite direction to the rotation of the heavy phase weir plate 106. The fluid reaction force acts positively on the rotation of the outlet cavity 201 (generating a torque to boost the drum) at the tangential injection port. The C-shaped path has a force-bearing surface formed at the bend to act positively on the rotation of the outlet cavity 201 under fluid impact. This force-bearing surface is an inclined surface 203A (an inclined guide surface that guides the fluid and transmits thrust) located on the inner wall of each outlet cavity 201. The incline of the inclined surface 203A points towards the nozzle 202 (ensuring smooth fluid flow to the nozzle). The injection direction of the nozzle 202 is towards the rotation path of the outlet cavity 201. The jetting direction is tangential to the circle formed by the diameter (spraying in the opposite direction along the tangent to maximize the recoil effect). A streamlined head 203 (drag-reducing leading edge, usually integrally machined) is formed at the end of the outlet cavity 201 away from the nozzle 202 to reduce wind resistance. A guide hole 112 (liquid inlet channel) is provided on the heavy phase weir plate 106, communicating with the C-shaped path inlet. Guide plates 205 (annular baffles) are installed at intervals below the heavy phase weir plate 106, with fixed positions relative to each other. A guide is formed between the heavy phase weir plate 106 and the guide plates 205 to collect the fluid from the wall side of the drum 105. The guide cavity (annular gap liquid collection area) and the drum 105 located below the heavy phase weir plate 106 are provided with a conical widening section 105A (this structure is designed to promote the accelerated flow of liquid and is usually machined as an integral part of the drum), so that the liquid inside and outside the drum 105 is accelerated and deflected into the guide hole 112 under the action of the guide plate 205 (the liquid is first accelerated in the conical area, then deflected by the guide plate, and then enters the guide hole to flow towards the kinetic energy recovery device). The cross section of the guide hole 112 is a cone with a diameter that gradually increases from bottom to top (to facilitate the smooth flow of high-speed fluid). The feeding device 300 includes a premixing chamber 301 (annular mixing chamber, coaxially arranged with the drum) fixedly sleeved in the inlet area of ​​the drum 105. A rotating shaft 104 passes through the drum 105 and extends into the premixing chamber 301, with a secondary mixing device (fine mixing component) at its end. A primary mixing device (coarse mixing component) is provided at the bottom of the premixing chamber 301. The drum 105, the premixing chamber 301, and the rotating shaft 104 are all driven by the same power source to rotate (synchronous rotation, compact structure, no need for additional sealing), so that the material is drawn into the premixing chamber 301 through the gap between the outer shell 103 and the premixing chamber 301, and after secondary mixing by the primary and secondary mixing devices, it enters the drum 105. The process involves the following steps: (1) Material flows in through the annular gap, undergoes initial mixing in the first stage, followed by fine homogenization in the second stage, and finally is pumped into the drum for separation. The second stage mixing device is configured as a mixing impeller 303 (conical stirring blades, enhancing shear dispersion) fixedly installed at the bottom of the rotating shaft 104 and synchronously driven by the shaft. The first stage mixing device is configured as a centripetal impeller 302 (radial suction structure, achieving centripetal convergence of materials) fixedly installed at the bottom of the premixing chamber 301 and synchronously driven by the chamber. Furthermore, an enhanced stirring impeller 304 (auxiliary turbulence blades) is fixedly installed on the inner wall of the premixing chamber 301, ensuring that the enhanced stirring impeller 304 is synchronously driven to rotate by the premixing chamber 301. The mixing effect is enhanced (the premixing chamber first drives the enhanced mixing impeller to rotate, then the agitation breaks the laminar flow, making the mixing more uniform); the bottom part of the drum 105 extends into the premixing chamber 301 and is provided with a feed impeller 115 (built-in feed impeller, which rotates synchronously with the drum to achieve active conveying) for pumping fluid into the drum 105; the longitudinal section of the mixing impeller 303 presents a cone shape with the diameter gradually increasing from bottom to top (inverted cone structure, which is conducive to guiding the material from the outside to the center); a spiral guide 306 (axial guide vanes) is fixedly sleeved on the outer wall of the premixing chamber 301 so that the spiral guide 306 is synchronously driven to rotate by the premixing chamber 301 to achieve the gap between the outer shell 103 and the premixing chamber 301. The liquid inside accelerates downward flow (first the spiral guide rotates, then pushes the liquid in the gap to quickly converge downward). A mixing baffle 305 (anti-backflow baffle) is fixedly installed on the top of the outer wall of the premixing chamber 301 to cooperate with the spiral guide 306 to prevent the liquid in the gap between the outer shell 103 and the premixing chamber 301 from flowing upward (first the baffle blocks the upward surge, then it works with the spiral guide to form a single downward flow channel). A pressure impeller 307 (radial return guide impeller) is fixedly connected to the top of the inner wall of the premixing chamber 301 so that the liquid on the outer side of the premixing chamber 301 is rotated to the middle of the premixing chamber 301 and sucked in (first the pressure impeller rotates to guide the outer peripheral liquid to the center, then promotes the material to smoothly enter the primary mixing device).

[0046] The working principle of this device is as follows: First, the heavy phase and light phase raw materials enter the annular flow channel between the premixing chamber 301 and the outer shell 103 through the heavy phase inlet 113 and the light phase inlet 114, respectively. Under the guidance and obstruction of the mixing baffle 305, the two-phase fluids flow axially downwards and generate initial tangential shear. At this time, the drive motor 102 starts, driving the drum 105 and the premixing chamber 301 fixedly connected to it to rotate synchronously at high speed through the rotating shaft 104. The spiral guide 306 provided on the outer wall of the premixing chamber 301 rotates accordingly, and its spiral blades generate a downward axial pumping force when rotating, forcing the fluid in the annular gap to be conveyed downwards, thereby ensuring that the material can be effectively captured by the centripetal impeller 302 located at the bottom. The centripetal impeller 302 rotates at high speed with the rotating shaft 104, generating a significant negative pressure in its inlet center region, which powerfully pumps the downward-conveyed two-phase fluid upwards into the center inlet at the bottom of the premixing chamber 301. This pumping process, accompanied by intense shearing and entrainment, completes the first discretization and preliminary mixing of the heavy and light phases.

[0047] Subsequently, the material entering from the bottom center of the premixing chamber 301 is immediately captured and subjected to a second high-intensity mixing by the coaxially mounted, suspended conical mixing impeller 303. The high-speed rotation of this impeller generates intense turbulence. Its unique conical structure not only enhances radial shear strength but also generates an axial force pointing towards the central axis of the drum 105, preferentially guiding the lighter, less dense phase upwards. This design ensures that the lighter phase tends to reach a higher liquid level before entering the main separation zone, effectively preventing secondary mixing and backmixing of the lighter phase with the settled heavier phase at the bottom of the drum 105, thus laying a fluid dynamic foundation for clear phase interface separation. Through the dedicated premixing chamber 301 located at the front end of the drum 105, this system completes two-stage progressive mixing within a compact, relatively enclosed high-intensity shear field before the material enters the main drum 105, significantly increasing the mass transfer surface area and mixing uniformity, creating excellent conditions for subsequent efficient extraction reactions.

[0048] Then, the mixture in the premixing chamber 301 is further sheared and homogenized by the reinforced stirring impeller 304 fixed inside the chamber, completing the third final mixing. Under the action of strong centrifugal force, some of the fluid that may be insufficiently mixed and rises along the inner wall of the premixing chamber 301 is forced to flow back to the middle of the chamber by the pressure impeller 307 rotating at the top of the chamber, forming an internal circulation to ensure that nothing is missed. Finally, all materials are sucked in by the feed impeller 115 at the bottom of the drum 105 and smoothly enter the main separation zone of the drum 105. The fluid entering the drum 105 rotates at high speed with the drum 105 and gradually rises along the axis. When it enters the tapered widening section 105A of the upper half of the drum 105 with a gradually expanding diameter, the separation environment is optimized in two ways: first, the separation radius increases, and according to the centrifugal force formula F_c = mω²r, the separation factor is significantly improved, and the separation driving force is enhanced; second, the tapered space provides a larger sedimentation storage volume for the heavy phase, reducing the risk of interface disturbance.

[0049] Inside the drum 105, the fluid rapidly stratifies under a centrifugal force field several times stronger than gravity: the heavy phase is thrown against the drum wall and flows upward along it; the light phase accumulates in the central region. The opening of the light phase weir 107 extends precisely to the light phase accumulation area, guiding the separated light phase to the light phase collection chamber 109, and finally discharging it from the light phase outlet 111. The heavy phase continues to rise along the drum wall, and after passing the top of the heavy phase weir 106, it is effectively captured by the guide plate 205 located on the separation side of the weir. The guide plate 205 smoothly guides the high-speed heavy phase fluid into the guide hole 112 (its tapered design, smaller at the bottom and larger at the top, facilitates fluid acceleration and stabilizes the flow rate), and then injects it into the outlet chamber 201. This chamber is precisely arranged along the tangential direction of the rotation circle of the drum 105 and is the core of kinetic energy conversion.

[0050] Within the outlet cavity 201, the high-speed fluid first impacts the fixed impact baffle 204, precisely splitting into two streams. One stream deflects to the left, entering the lower half of the nozzle 202, but the lower half of the nozzle 202 is closed, so subsequent water flow can only come from the other side; the other stream deflects to the right, first impacting the inclined surface 203A within the head 203. The inclined surface 203A decomposes the normal impact force of the fluid, generating a tangential component force, directly creating a positive driving torque on the cavity (i.e., the rotating drum 105). Subsequently, this stream of fluid bypasses the impact baffle 204 and is ejected from the upper half of the nozzle 202. All fluid ejected from the nozzle 202 has its ejection direction set opposite to the rotation direction of the rotating drum 105. According to Newton's third law, the reaction force generated by the jet stream again applies a strong positive torque to the rotating drum 105. The torque generated by the impact of the inclined plane 203A and the jet thrust is superimposed in the same direction, forming a significant auxiliary driving effect, directly reducing the load on the main drive motor 102 and achieving significant energy saving. The streamlined design of the cavity head 203 effectively reduces the wind resistance loss generated by friction with air during high-speed rotation. This invention has significant advantages over traditional centrifugal separators 100. Conventional designs typically reduce the flow rate of the separated liquid to prevent the high-speed liquid jet from generating reverse impact resistance on the drum 105, thereby avoiding overload or mechanical damage to the drive motor 102. However, this approach inherently consumes the kinetic energy carried by the liquid, resulting in energy waste and limiting the equipment's ability to handle high-flow-rate materials.

[0051] This invention innovatively incorporates a conical widening section 105A in the heavy phase outlet 110 region of the drum 105. This structure is not for deceleration, but rather utilizes the principle of centrifugal acceleration to further increase the flow velocity of the heavy phase liquid near the wall of the drum 105 as it flows through the conical widening section 105A. The accelerated high-speed liquid is guided by the guide plate 205, enters the C-shaped flow channel of the kinetic energy recovery device through the conical guide hole 112 on the heavy phase weir plate 106, and finally is ejected at high speed from the tangential nozzle 202 in the opposite direction to the rotation of the drum 105. According to the principle of conservation of momentum, the reaction torque generated by this reverse injection is consistent with the rotation direction of the drum 105, thereby actively propelling the drum 105 to rotate and achieving effective recovery and reuse of the liquid's kinetic energy.

[0052] Reaction washing clarification and concentrating machine: such as Figure 8As shown, the tank A01 provides the reaction space for the materials. The design pressure, design temperature, and equipment materials of tank A01 can be designed according to specific requirements. An external jacket is also provided, with a heat source inlet at the top and a heat source outlet at the bottom. The end cap typically has a material inlet, a washing liquid inlet, a supernatant suction port, as well as a pressure gauge port, a safety valve port, an air inlet, and an exhaust port. The heat source, automatic valve, and material temperature sensor are interlocked to achieve safe and automated control of the temperature of sensitive materials. Specific structural details are not described in detail here.

[0053] A stirring motor A2 is installed on the top of tank A01. The stirring motor A2 is fixed to a lifting system A3 outside tank A01. The lifting system A3 can be a hydraulic or pneumatic lifting system, used to drive the stirring motor A2 to move vertically. The stirring motor A2 drives the stirring shaft A21 to rotate via a reducer. Driven by the stirring motor A2, the stirring shaft A21 rotates in both directions and moves up and down, achieving multi-dimensional washing to maximize the washing effect and prevent the bottom of the impeller A22 from rubbing against the filter cake. The stirring shaft A21 and the impeller A22 are welded together, eliminating the need for bolts. The impeller A22 includes a long S-shaped impeller and a short S-shaped impeller. The surfaces of both the long and short impellers are vertically arranged, and their axes of symmetry coincide with the axis of the stirring shaft A21. The length directions of the long and short impellers after installation are perpendicular to each other. The double-S blade structure creates multi-dimensional composite motion through forward and reverse rotation and lifting, which can thoroughly mix materials. The stirring speed is generally below 30 rpm, and this controlled stirring speed greatly helps reduce the production risks associated with sensitive materials. The unique design of the double-S blades can reduce energy consumption while ensuring mixing intensity, thus achieving energy-saving effects.

[0054] A filter disc A7 is horizontally arranged inside the tank A01. In one embodiment, the filter disc A7 may include a filter cloth pressure plate, a filter cloth, and a perforated plate arranged sequentially from top to bottom. The filter cloth pressure plate and the perforated plate are welded together to press the filter cloth tightly. The overall structure is directly pressed and fixed using the flange face inside the tank A01, without bolts. The filter disc A7 divides the inner cavity of the tank A01 into an upper working chamber and a lower mother liquor chamber. A material inlet pipe A4 is installed on the tank A01. The material inlet pipe A4 is C-shaped, and its material outlet is flush with the inner wall of the tank A01 to prevent the material from impacting the filter disc A7 at the bottom during feeding and causing danger. A flow meter and a control valve are installed at the material inlet of the material inlet pipe A4 to control the material injection rate in real time. The bottom surface of the tank A01 is sloped to avoid mother liquor stagnation.

[0055] A radar level gauge is also installed inside tank A01 to monitor the liquid level in real time. By installing a sight glass on tank A01 in conjunction with the radar level gauge, dual monitoring of the slurry level can be achieved. Flow meters are installed on the feed, inlet, and outlet pipes of tank A01, allowing the control system to calculate and display the dryness / wetness trend of the material inside the tank in a timely manner, interlocking with the actuators and providing alerts when necessary.

[0056] The slurry suction pipe A6 extends into the working chamber and is located above the center of the filter disc A7. The optimal distance between the pipe opening and the filter cloth gap of the filter disc A7 is 8mm. The opening of the slurry suction pipe A6 is designed in a horseshoe shape to reduce discharge resistance. The slurry is discharged to downstream equipment via a peristaltic hose pump. A control valve and pressure sensor are installed at the outlet of the slurry suction pipe A6. A backwashing device can also be installed below the filter disc in tank A01 to clean the filter disc A7 from bottom to top, preventing clogging. A washing spray pipe is horizontally arranged inside tank A01, positioned above the bottom surface of the liquid seal seat A11. Washing spray balls A5 are evenly distributed on the washing spray pipe, with the spray direction of the washing spray balls A5 pointing towards the filter disc A7.

[0057] A liquid seal seat A11 is installed on the top of the tank A01. The liquid seal seat A11 has a sleeve-shaped structure with an open top, and a sealing ring is installed at the contact surface between the liquid seal seat A11 and the tank A01. An insertion hole 11C with a diameter larger than that of the stirring shaft A21 is coaxially opened at the bottom of the liquid seal seat A11. The stirring shaft A21 passes through the insertion hole 11C of the liquid seal seat A11 from outside the tank A01, thus entering the working chamber of the tank A01. The liquid seal seat A11 includes an outer baffle 11A and an inner baffle 11B arranged coaxially. Both the outer baffle 11A and the inner baffle 11B are annular plates, and the inner baffle 11A and the outer baffle 11B enclose a liquid seal annular cavity 11D.

[0058] The replenishment pipe 11F is inserted vertically into the liquid seal ring cavity 11D, and the medium in the tank A01 is drawn and injected into the liquid seal ring cavity 11D. A liquid seal barrel A23 is coaxially fixed to the shaft of the stirring shaft A21 located outside the tank A01. The liquid seal barrel A23 includes a liquid seal ring A231 coaxially fixed to the stirring shaft A21. An annular liquid baffle plate A232 is coaxially fixed below the liquid seal ring A231. The liquid baffle plate A232 cooperates with the liquid seal ring A231 to make the liquid seal barrel A23 have a barrel-shaped structure with an open bottom. The diameter of the liquid baffle plate A232 is smaller than the diameter of the outer baffle 11A and larger than the diameter of the inner baffle 11B. The bottom of the liquid baffle plate A232 is always below the liquid surface in the liquid seal ring cavity 11D.

[0059] The fixing method between the liquid sealing ring A231 and the stirring shaft A21 is not limited, but it is preferable to arrange bolts radially to fix the liquid sealing ring A231 and the stirring shaft A21. To improve the sealing effect, a sealing ring is installed at the contact surface between the stirring shaft A21 and the liquid sealing ring A231. A level gauge 11G for measuring the liquid level in the liquid sealing ring cavity 11D is also installed inside the liquid sealing ring cavity 11D. While the stirring shaft A21 drives the liquid sealing tank A23 to move up and down, the replenishment pipe 11F replenishes or extracts the medium into the liquid sealing ring cavity 11D, so that the bottom surface of the liquid sealing tank A23 is always below the liquid level in the liquid sealing ring cavity 11D. When the tank A01 is working, some of the leaked material is blocked by the liquid sealing ring A231 after passing through the annular gap between the insertion hole 11C and the stirring shaft A21, and enters the liquid sealing ring cavity 11D, where it mixes with the medium in the liquid sealing ring cavity 11D to achieve the liquid sealing effect.

[0060] Process-controlled pneumatic discharge filter: such as Figure 11 As shown, the system includes a collection chamber 33 (annular collection space located below the filtration zone) for containing filtrate. An inverted U-shaped tube 41 (a liquid seal and drainage control structure that utilizes the siphon principle to achieve controllable discharge) is installed outside the collection chamber 33. A mother liquor outlet 65 (main discharge port, used to discharge filtrate under normal operating conditions) is formed at the lowest liquid level of the collection chamber 33, extending to the outside. One end of the inverted U-shaped tube 41 is connected to the mother liquor outlet 65 through a variable length tube structure (a flexible connection to adapt to lifting and lowering movements). The other end of the inverted U-shaped tube 41 is a mother liquor outlet 64 (the mother liquor outlet 64 is always lower than the mother liquor outlet 65 to ensure siphon pressure). A lifting and adjusting device 40 is also installed outside the collection chamber 33 to drive the inverted U-shaped tube 41 to move vertically back and forth to control the height difference between the mother liquor outlet 64 and the lowest liquid level (the siphon force is controlled by adjusting the liquid seal height).

[0061] According to one embodiment of the present invention, the variable length tube structure includes a connecting pipe 43 (fixed guide sleeve) vertically installed on the mother liquor outlet 65, and the connecting end of the inverted U-shaped tube 41 is slidably sleeved in the connecting pipe 43 through a sealing seat 42 (sealed sliding fit, which allows up and down movement while preventing leakage, usually using polytetrafluoroethylene or rubber seals).

[0062] According to one embodiment of the present invention, the lifting adjustment device 40 is a pneumatic lifting device (commonly telescopic cylinders, which have fast response and good explosion-proof performance). The air source interface of the pneumatic lifting device is connected to or disconnected from the air source vehicle through a pipeline with a control valve 52 of the adjustment device (first open the control valve, then introduce compressed air, and then the cylinder pushes the inverted U-shaped tube to lift and lower, thereby adjusting the discharge height).

[0063] According to one embodiment of the present invention, a conical ring 34 (a flow guiding sedimentation structure that allows fine particles to slide down the inclined plane back to the filter area) is provided in the liquid accumulation chamber 33 for settling particles using the principle of inclined plate sedimentation, and the bottom end of the conical ring 34 forms an annular opening 37 (a sediment return channel).

[0064] According to one embodiment of the present invention, the device further includes a cylindrical body component 3 and a paddle component 1 (a rotating assembly for stirring and air-blowing unloading) rotatably mounted on the cylindrical body component 3. The cylindrical body component 3 includes a shell 35 (the main outer shell of the equipment, typically made of welded carbon steel or stainless steel). A top cover plate 30 (a sealing top cover) is fixedly provided at the upper end of the shell 35. A conical cylinder 31 (an inner cylinder supporting the filter structure) is fixedly installed inside the shell 35. A feed inlet 61 (material inlet), an air inlet 62 (air source interface for filter press), and an exhaust port 63 (exhaust balance port) are installed on the top cover plate 30. The feed inlet 61 is connected to or isolated from the material workshop through a pipe equipped with a feed control valve 55 (the feed valve is opened first, and then the material is injected for filtration). The air inlet 61 is connected to or isolated from the material workshop through a pipe equipped with a feed control valve 55. 2. The gas supply vehicle is connected or disconnected through a pipe with an intake valve (for pressurization during the filtration stage). The exhaust port 63 is connected or disconnected from the atmosphere through a pipe with an exhaust control valve 56 (exhausting during the initial filtration stage and closing to maintain pressure in the later stage). The lower end of the conical cylinder 31 is provided with an opening area 36 (liquid outflow area). A conical filter disc 32 is fixedly connected to the inner conical surface of the conical cylinder 31 to cover the opening area 36 (the filter medium support, usually covered with filter cloth or sintered metal mesh). The outer conical surface of the conical cylinder 31 and the inner wall of the shell 35 form a liquid collection chamber 33 (filtrate collection area). After the pipes containing the filtration intake valve 53 and the regulating device control valve 52 are closed, they are controlled by the main air valve 51 (centralized management of the air path to improve operational safety).

[0065] According to one embodiment of the present invention, a drive component 2 (gear motor or hydraulic motor) is fixedly mounted on the upper cover plate 30. The blade component 1 includes a rotary joint 11 (a dynamic sealing joint for supplying air to the rotating component). The upper end of the fixed portion of the rotary joint 11 is drively connected to the output end of the drive component 2, and the lower end of the fixed portion of the rotary joint 11 is fixedly connected to a main shaft 12 (central drive shaft). The main shaft 12 is connected to a blade support 14 (radial support arm) via a side shaft 13. An air nozzle 15 (purge nozzle) is fixedly mounted on the blade support 14. The rotating portion of the rotary joint 11 is connected to the air supply... The control box 10 is connected to the air source workshop (compressed air first enters the control box, then is sent to the rotating part through the rotary joint, and then sprayed out from the nozzle). The control box 10 can be a pneumatic control box in the existing technology (integrating pressure regulation, filtration and control functions), and a gas control valve 54 is installed in the control box 10. The main shaft 12, side shaft 13 and blade support 14 are all formed with channels (internal air passages, usually drilled) for guiding the airflow in the rotary joint 11 to the nozzle 15. The range of air jets from the nozzle 15 on the conical filter plate 32 is intersecting or complementary to form a complete purging surface (ensuring that there are no dead corners on the surface of the filter plate for unloading). The lower end of the conical cylinder 31 is fixedly connected to a discharge port 66 (solid filter cake outlet) extending to the outside. The discharge port 66 is used to discharge filter cake to the solid product material workshop (air blowing unloading is completed first, then the discharge valve is opened, and then the filter cake falls automatically). The discharge port 66 is equipped with an automatic discharge valve 510 (a normally closed pneumatic or electric valve to prevent leakage). Mother liquor outlet 2 64 is connected to the mother liquor truck through a pipe with a mother liquor U-tube discharge valve 57 (controlling the switch of the inverted U-shaped tube discharge path). Mother liquor outlet 1 65 is connected to the mother liquor truck through a pipe with a mother liquor discharge valve 58 (used for emergency emptying or cleaning discharge); the mother liquor outlet is connected to the air source workshop through a pipe with a backflush air inlet valve 59 (first close the discharge valve, then open the backflush valve, and then compressed air backflush the filter disc to achieve regeneration). The pneumatic lifting equipment is a telescopic cylinder (compact structure, stable thrust, commonly used in industrial automation lifting scenarios). The core working principle of the process-controlled air-blown unloading filter lies in the integration of siphon-assisted dynamic pressure regulation and rotary pneumatic scraper technology to achieve precise and optimized control of the entire solid-liquid separation process. The specific process is as follows: Filtration preparation and feeding: The suspension enters the sealed working chamber of the conical cylinder 31 through the feed inlet 61. Under the initial pump pressure, the liquid passes through the filter disc and enters the outer liquid collection chamber 33, while the solids are trapped to form a filter cake. The inverted conical ring 34 structure of the liquid collection chamber 33 can utilize the principle of inclined plate sedimentation to quickly capture and separate the fine particles that "run away" in the initial stage, and discharge the turbid liquid through the bottom mother liquor outlet 65 for recovery.

[0066] After entering the main filtration stage, the operation can switch the drainage mode according to process requirements. A key innovation lies in the use of a height-adjustable inverted U-shaped pipe 41 for drainage: the height difference H between the siphon outlet and the liquid level in the collection chamber 33 can be dynamically changed by adjusting the pneumatic lifting device. This siphon force, combined with the positive pressure of the compressed gas introduced through the air inlet 62, constitutes a programmable adjustable total filtration driving force. In the feeding / washing stage, H is increased to reduce ΔP and flow rate, promoting uniform filter cake formation or improving washing efficiency; in the main filtration / drying stage, H is decreased to increase ΔP and flow rate, increasing throughput and obtaining a filter cake with lower moisture content. After filtration, the equipment employs a unique non-contact unloading system. First, the backflush valve can be opened to introduce gas from the back of the filter disc to loosen the filter cake. Subsequently, the transmission components are activated to rotate the paddle support 14, and the air path is opened, allowing compressed gas to be delivered through the hollow main shaft 12, side shaft 13, and support to the evenly distributed air nozzles 15, forming a rotating "air scraper" covering the entire conical filter disc 32 inverted U-shaped tube 41, completely peeling off the filter cake and discharging it from the bottom discharge port 66. Through siphon pressure regulation, the filtration driving force is intelligently matched with each process stage, and through the pneumatic scraper, the filter disc is cleaned non-destructively and efficiently, forming a precision solid-liquid separation solution integrating anti-material spillage, adaptive filtration, efficient washing, powerful pressing and drying, and clean unloading.

[0067] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

Claims

1. A wet recycling method for waste batteries, characterized in that, Includes the following steps: S1. The battery pack is pre-crushed to separate out the black powder; S2. Acid leaching is performed on the black powder to remove slag. The lithium precipitation mother liquor obtained after treatment is then introduced into the lithium precipitation mother liquor centrifugal extraction lithium extraction process. The filter residue obtained after processing is transported to a process-controlled air-blown unloading filter for further solidification treatment, and the resulting lithium precipitation mother liquor enters the lithium precipitation mother liquor centrifugal extraction lithium extraction process. S3. Collect the lithium-precipitated mother liquor from S2 and extract lithium by centrifugation. S31. Adjust the pH of the lithium precipitation mother liquor to 12.5-13.5 with alkaline solution to obtain the prepared solution; S32. The prepared liquid and the organic extractant are subjected to countercurrent contact in a centrifugal extractor with 2 to 5 stages connected in series at an oil-water volume ratio of 1:2 to 5:1 to separate the lithium-loaded organic phase and the raffinate. S33. The lithium-loaded organic phase and the detergent are subjected to countercurrent contact in a centrifugal extractor with 2 to 5 stages connected in series at a water-oil volume ratio of 1:10 to 1:1 to separate the washed organic phase and the washing liquid containing impurities. S34. The washed organic phase is mixed and contacted with the back-extraction agent to separate the lithium-rich aqueous phase and the empty organic phase. S35. The empty organic phase and the washing water are contacted in a centrifugal extractor at a water-oil volume ratio of 1:3 to 3:1 to separate the regenerated organic extractant and acidic wastewater.

2. The wet recycling method for waste batteries according to claim 1, characterized in that, In step S4, the volumetric flow rate ratio of the back-extraction agent to the washed organic phase is 1:10–1:1; the alkaline solution is a sodium hydroxide solution; the lithium concentration of the lithium precipitation mother liquor is 1–5 g / L; the organic extractant includes a mixture of β-diketone extractants and sulfonated kerosene; the back-extraction agent is a 1–5 mol / L sulfuric acid solution, or pure water or tap water with continuous carbon dioxide gas flow. When carbon dioxide aerated water is used as the back-extraction agent, the back-extraction is carried out in a stirred back-extraction tower or centrifugal extractor equipped with a gas distributor, and CO2 is continuously introduced.

3. The wet recycling method for waste batteries according to claim 1, characterized in that, The extraction unit in S3 includes a material pipeline (401), a raffinate pipeline (402), a material storage tank (403), a material booster pump (404), an extractant pipeline (405), an extractant storage tank (406), an extractant booster pump (407), and a multi-stage centrifugal extractor (408). The centrifugal extractor (408) is the same equipment as the aforementioned equipment. The material pipeline (401) is connected in sequence to the material storage tank (403) and the material lifting pump (404), and then connected in series with the water phase inlet and outlet of the first-stage to N-stage centrifugal extractor (408), and finally flows into the raffinate pipeline (402). The extractant pipeline (405) is connected in sequence to the extractant storage tank (406) and the extractant booster pump (407), and then connected in series with the organic phase inlet and outlet of the first-stage to N-stage centrifugal extractor (408), and finally discharged into the washing section unit.

4. A wet recycling method for waste batteries according to any one of claims 1 to 3, characterized in that, In the acid leaching and slag removal process of S2, at least two sets of leaching tanks (706) are included. Compressed air pipeline (701), black powder pipeline (702), hydrogen peroxide pipeline (703), concentrated sulfuric acid pipeline (704) and water supply pipeline (705) supply materials to each leaching tank (706) to dissolve the black powder in the leaching tank (706). The material discharged from the leaching tank (706) is successively transported to the reaction washing clarification and thickening machine (A1) after passing through the slurry transfer tank (707) and the slurry pump (708). After the reaction washing clarification and thickening machine (A1) processes and separates the material, the mother liquor is transported to the belt material transfer tank (709) and the filter residue is transported to the process-controlled air-blowing unloading filter. After the process-controlled air-blowing unloading filter further processes the filter residue, the recovered mother liquor enters the material pipeline (401) of the lithium extraction process of the lithium precipitation mother liquor centrifugal extraction. The mother liquor entering the belt-type liquid transfer tank (709) passes through the transfer tank centrifugal pump (710), the belt-type liquid storage tank (711), and the storage tank centrifugal pump (712) in sequence before entering the material pipeline (401) of the lithium extraction process of the lithium mother liquor centrifugal extraction.

5. The wet recycling method for waste batteries according to claim 4, characterized in that, After being split, the compressed air pipeline (701) and the water supply pipeline (705) supply compressed air and water to the reaction washing clarification concentrator (A1).

6. The wet recycling method for waste batteries according to claim 4, characterized in that, The process-controlled air-blown unloading filter includes a liquid collection chamber (33) for containing filtrate. An inverted U-shaped tube (41) is provided outside the liquid collection chamber (33). A mother liquor outlet (65) extending to the outside is formed at the lowest liquid level of the liquid collection chamber (33). One end of the inverted U-shaped tube (41) is connected to the mother liquor outlet (65) through a variable length tube structure. The other end of the inverted U-shaped tube (41) is the mother liquor outlet (64). A lifting adjustment device (40) is also provided outside the liquid collection chamber (33) for driving the inverted U-shaped tube (41) to move vertically back and forth to control the height difference between the mother liquor outlet (64) and the lowest liquid level.

7. The wet recycling method for waste batteries according to claim 6, characterized in that, The variable length tube structure includes a connector (43) vertically installed on the mother liquor outlet (65), and the connecting end of the inverted U-shaped tube (41) is slidably sleeved inside the connector (43) by a sealing seat (42).

8. The wet recycling method for waste batteries according to claim 6, characterized in that, The lifting adjustment device (40) is a pneumatic lifting device. The air source interface of the pneumatic lifting device is connected or disconnected from the air source vehicle through a pipe with a control valve (52) of the adjustment device. A conical ring (34) is provided in the liquid accumulation chamber (33) for settling particles using the principle of inclined plate sedimentation.

9. The wet recycling method for waste batteries according to claim 4, characterized in that, The reaction washing clarification and concentrating machine (A1) has a filter plate (A7) installed inside its tank (A01). The filter plate (A7) divides the tank cavity (A01) into an upper working chamber and a lower mother liquor chamber. A stirring shaft (A21) extends from the working chamber through a liquid seal seat (A11) to the outside of the tank (A01) and is coaxially fixed with the motor shaft of the stirring motor (A2). A lifting system (A3) is installed on the tank (A01) to drive the stirring motor (A2) and the stirring shaft (A21) to perform lifting and lowering movements. A mother liquor discharge pipe (A8) communicating with the mother liquor chamber is located at the bottom of the tank (A01). It also includes a liquid seal seat (A11) installed at the top of the tank (A01). The seat (A11) has a top-opening, sleeve-shaped structure. The bottom of the liquid seal seat (A11) has an insertion hole (11C) for the stirring shaft (A21) to pass through. The diameter of the insertion hole (11C) is larger than the diameter of the stirring shaft (A21). The liquid seal seat (A11) includes an outer baffle (11A) and an inner baffle (11B) arranged coaxially. There is a liquid seal annular cavity (11D) between the inner baffle (11A) and the outer baffle (11B) for the injection of sealing medium. A liquid seal barrel (A23) with a bottom opening is coaxially fixed on the stirring shaft (A21). The opening of the liquid seal barrel (A23) is inserted downward into the liquid seal annular cavity (11D), and the opening of the liquid seal barrel (A23) is located below the liquid surface of the liquid seal annular cavity (11D).

10. The wet recycling method for waste batteries according to claim 9, characterized in that, The replenishment pipe (11F) draws the medium from the tank (A01) and replenishes it into the liquid seal ring cavity (11D). A level gauge (11G) for measuring the liquid level in the liquid seal ring cavity (11D) is also installed on the liquid seal seat (A11). While the stirring shaft (A21) moves up and down in the vertical direction, the replenishment pipe (11F) replenishes the medium into the liquid seal ring cavity (11D) so that the opening of the liquid seal bucket (A23) is always below the liquid level in the liquid seal ring cavity (11D).

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