Lithium iron phosphate retired battery recycling wastewater treatment system and method

Abstract

The application discloses a lithium iron phosphate retired battery recycling wastewater treatment system and method, and belongs to the field of wastewater treatment. The lithium iron phosphate retired battery recycling wastewater treatment system comprises an acid-resistant ultrafiltration membrane device, a high-pressure reverse osmosis device, a reverse osmosis device, a mixer, a tubular membrane, an electrodialysis device and a bipolar membrane electrodialysis device. The water outlet of the acid-resistant ultrafiltration membrane device is communicated with the water inlet of the high-pressure reverse osmosis device. The water outlet of the high-pressure reverse osmosis device is communicated with the water inlet of the reverse osmosis device. The concentrated water outlet of the high-pressure reverse osmosis device is respectively communicated with two water inlets of the mixer. The water outlet of the mixer is communicated with the water inlet of the tubular membrane. The water outlet of the tubular membrane is communicated with the water inlet of the electrodialysis device. The concentrated water outlet of the electrodialysis device is communicated with the water inlet of the bipolar membrane electrodialysis device. The application can realize the resource utilization of lithium iron phosphate retired battery recycling wastewater, obtain sulfuric acid, sodium hydroxide and reusable water, and the whole process has less by-product wastewater.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment, and particularly relates to a wastewater treatment system and method for recycling retired lithium iron phosphate batteries. Background Technology

[0002] While new energy vehicles are developing rapidly, my country is also facing a wave of retired lithium iron phosphate batteries. Currently, the commonly used method for recycling retired lithium iron phosphate batteries is wet recycling. After separating the positive electrode material powder from the disassembled batteries, it is leached with sulfuric acid to obtain metal ions. Then, cobalt, nickel, and manganese sulfates or hydroxides are obtained through alkaline precipitation and solvent extraction. This process generates a large amount of high-salt wastewater, causing pollution. The wastewater mainly contains sodium ions and sulfate ions. Therefore, there is an urgent need for a wastewater treatment system and method for the recycling of retired lithium iron phosphate batteries. Summary of the Invention

[0003] The purpose of this invention is to provide a wastewater treatment system and method for recycling retired lithium iron phosphate batteries, so as to overcome at least one of the above-mentioned defects in the prior art.

[0004] To achieve this objective, the present invention adopts the following technical solution:

[0005] The wastewater treatment system for the recycling of retired lithium iron phosphate batteries provided by this invention includes an acid-resistant ultrafiltration membrane device, a high-pressure reverse osmosis device, a reverse osmosis device, a mixer, a tubular membrane, an electrodialysis device, and a bipolar membrane electrodialysis device. The product water end of the acid-resistant ultrafiltration membrane device is connected to the inlet water end of the high-pressure reverse osmosis device, and the product water end of the high-pressure reverse osmosis device is connected to the inlet water end of the reverse osmosis device. The mixer has two inlet water ends, and the concentrate water end of the high-pressure reverse osmosis device is connected to the two inlet water ends of the mixer. The outlet water end of the mixer is connected to the inlet water end of the tubular membrane, the product water end of the tubular membrane is connected to the inlet water end of the electrodialysis device, the concentrate water end of the electrodialysis device is connected to the inlet water end of the bipolar membrane electrodialysis device, the concentrate water end of the tubular membrane is connected to the inlet water end of the acid-resistant ultrafiltration membrane device, and the desalination end of the electrodialysis device is connected to the inlet water end of the reverse osmosis device.

[0006] Preferably, the acid-resistant ultrafiltration membrane device uses a ceramic ultrafiltration membrane, a polytetrafluoroethylene ultrafiltration membrane, or a silicon carbide ultrafiltration membrane.

[0007] Preferably, the mixer includes a housing, a stirrer, a oscillating assembly, an inlet pipe, a venturi tube, a dosing assembly, a transmission assembly, a first rotating shaft, a first bearing seat, and an impeller. Inlet pipes are fixedly connected to the upper sides of both the left and right side walls of the housing. A venturi tube is fixedly connected to the outer end of the inlet pipe, and the venturi tube is connected to the concentrate end of the high-pressure reverse osmosis device via a pipe. The dosing end of the dosing assembly is fixedly connected to the throat of the venturi tube. A first bearing seat is fixed to the outer side wall of the inlet pipe. The inner end of the first rotating shaft passes through the first bearing seat and the side wall of the inlet pipe, and extends into the interior of the inlet pipe where an impeller is fixed. The contact point between the first rotating shaft and the inlet pipe is sealed. The outer end of the first rotating shaft is connected to the dosing assembly via the transmission assembly. An oscillating assembly is fixed to the top of the housing, and a stirrer is fixed to the oscillating end of the oscillating assembly. The stirring end of the stirrer extends into the interior of the housing.

[0008] Preferably, the dosing assembly includes a dosing pipe, a tank, a partition, a baffle, a connecting rod, a bracket, a first guide rod, a first guide sleeve, a second guide rod, a second guide sleeve, a contact block, a cam, a second bearing seat, and a second rotating shaft. The top of the throat of the venturi tube is fixedly connected to the tank, and the top of the dosing pipe is fixedly connected to the tank. A partition is fixedly installed in the lower part of the tank, and the partition has a first through hole. First guide sleeves are fixedly installed on both the left and right side walls of the tank. The inner end of the first guide rod passes through the first guide sleeve and the side wall of the tank, and extends into the interior of the tank where a baffle is fixedly installed. The top of the baffle... The wall contacts the bottom wall of the partition, the baffle has a second through hole, a second bearing seat is fixed on the upper side wall of the box, the second rotating shaft passes through the second bearing seat and is connected to the first rotating shaft through the transmission assembly, a cam is fixed on the second rotating shaft, a bracket is fixed on the top of the box, a second guide sleeve is fixed on the top of the bracket, a second guide rod passes through the second guide sleeve, a contact block is fixed on the end of the second guide rod near the cam and the outer end of the first guide rod near the cam, and the end of the second guide rod away from the cam and the outer end of the first guide rod away from the cam are connected by a connecting rod.

[0009] Preferably, the transmission assembly includes a driving wheel, a driven wheel, and a transmission belt. The driving wheel is fixed to a first rotating shaft, the driven wheel is fixed to a second rotating shaft, and the driving wheel and the driven wheel are connected by a transmission belt.

[0010] Preferably, the oscillating assembly includes an oscillating seat, a connecting arm, and a left-right moving assembly. A stirrer is fixed to the bottom of the oscillating end of the oscillating seat, and the connecting arm is hinged to the left end of the moving end of the left-right moving assembly. The left end of the connecting arm is hinged to the top of the oscillating end of the oscillating seat.

[0011] Preferably, the left-right moving assembly includes a column, a slide rail, a slider, a rack, a gear, a mounting bracket, a third bearing seat, a worm gear, a worm, a third rotating shaft, and a forward / reverse motor. A column is fixed to the right side of the top of the housing, a slide rail is fixed to the top of the column, a slider is slidably connected to the top of the slide rail, a rack is fixed to the top of the slider, the left end of the rack is hinged to the right end of the connecting arm, a mounting bracket is fixed to the top of the slide rail, a forward / reverse motor and a third bearing seat are fixed to the inner top wall of the mounting bracket, a worm is fixed to the bottom of the forward / reverse motor, the third rotating shaft passes through the third bearing seat, the worm gear and gear are fixed to the third rotating shaft, the worm gear is located in front of the rack, the worm gear meshes with the worm, and the gear meshes with the rack.

[0012] Preferably, the swing arm includes a hinge seat, a swing arm, and a mounting plate. The lower part of the swing arm is hinged to the hinge seat, the bottom of the swing arm is fixed to the mounting plate, the stirrer is fixed to the mounting plate, and the upper part of the swing arm is hinged to the left end of the connecting arm.

[0013] Preferably, a drain pipe is fixedly connected to the bottom of the box, and a valve is installed on the drain pipe.

[0014] This invention also provides a method for treating wastewater from the recycling of retired lithium iron phosphate batteries. The method utilizes the aforementioned wastewater treatment system and includes the following steps: The wastewater is fed into an acid-resistant ultrafiltration membrane device for ultrafiltration treatment; the permeate obtained from the acid-resistant ultrafiltration membrane device is fed into a high-pressure reverse osmosis device; the permeate obtained from the high-pressure reverse osmosis device is fed into a reverse osmosis device; the permeate obtained from the reverse osmosis device is reused; the concentrated water obtained from the high-pressure reverse osmosis device is mixed with flocculant and defluorinating agent in a mixer; after mixing, the effluent from the mixer enters a tubular membrane; the concentrated water obtained from the tubular membrane is fed into an acid-resistant ultrafiltration membrane device; the permeate obtained from the tubular membrane is fed into an electrodialysis device; the desalinated water obtained from the electrodialysis device is fed into a reverse osmosis device; and the concentrated water obtained from the electrodialysis device is fed into a bipolar membrane electrodialysis device for treatment to obtain sulfuric acid and sodium hydroxide.

[0015] The beneficial effects of this invention are as follows:

[0016] 1. It can realize the resource utilization of wastewater from the recycling of retired lithium iron phosphate batteries, and obtain sulfuric acid, sodium hydroxide and reusable water, with little by-product wastewater in the whole process.

[0017] 2. The mixing operation is carried out by the stirrer. The oscillating component drives the stirrer to oscillate, and the stirring is carried out at the same time. This method of mixing is more thorough and the mixing efficiency is higher.

[0018] 3. The addition of influent and chemicals is achieved through a venturi tube, allowing for rapid and preliminary mixing of wastewater and chemicals.

[0019] 4. The impeller further enhances the mixing of the defluorinating agent and wastewater. The impeller not only further mixes the agent and wastewater, but also drives the dosing assembly.

[0020] 5. The dosing unit does not require power to drive the dosing; instead, it is hydraulically driven, which is energy-saving and environmentally friendly.

[0021] 6. By combining the impeller with the influent flow rate, the effect of quantitative dosing can be achieved. The dosage is matched with the influent flow rate, resulting in excellent dosing effect without the need for additional quantitative dosing equipment.

[0022] 7. By adding chemicals intermittently, the concentration of chemicals caused by concentrated addition is avoided, which is not conducive to subsequent mixing. Furthermore, the dosage can be adjusted according to the influent flow rate.

[0023] 8. The worm gear mechanism ensures the fixed swing position. When the forward and reverse motors stop rotating after swinging to a certain angle, the swing angle is still maintained and no deviation occurs. Attached Figure Description

[0024] Figure 1 This is a system block diagram of the present invention.

[0025] Figure 2 This is a schematic diagram of the structure of the present invention.

[0026] Figure 3 This is a schematic diagram of the structure of the water inlet pipe, venturi tube, impeller, dosing assembly, and transmission assembly of the present invention.

[0027] Figure 4 This is a schematic diagram of the structure of the stirrer, the oscillating component, and the housing of the present invention.

[0028] Figure 5 This is a schematic diagram of the left-right moving component of the present invention.

[0029] The labels in the attached diagram are as follows: 100-acid-resistant ultrafiltration membrane device, 200-high-pressure reverse osmosis device, 300-reverse osmosis device, 400-mixer, 500-tubular membrane, 600-electrodialysis device, 700-bipolar membrane electrodialysis device, 1-box, 2-stirrer, 3-oscillating assembly, 4-inlet pipe, 5-Venturi tube, 6-dosing assembly, 7-transmission assembly, 8-first rotating shaft, 9-first bearing seat, 10-impeller, 51-throat, 61-dosing pipe, 62-tank, 63-partition plate, 64-baffle, 65-connecting rod, 66-support, 67-first guide rod, 68-first guide sleeve, 69-second guide rod, 610-second guide... 611-Contact block, 612-Cam, 613-Second bearing seat, 614-Second rotating shaft, 615-First through hole, 616-Second through hole, 71-Driving wheel, 72-Driven wheel, 73-Transmission belt, 31-Swing seat, 32-Connecting arm, 33-Left and right moving assembly, 331-Column, 332-Slide rail, 333-Slider, 334-Rack, 335-Gear, 336-Mounting bracket, 337-Worm gear, 338-Worm, 339-Third rotating shaft, 3310-Forward and reverse motor, 3311-Third bearing seat, 311-Hinge seat, 312-Swing arm, 313-Mounting plate, 11-Drain pipe, 12-Valve. Detailed Implementation

[0030] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0031] Contents not described in detail in this specification are prior art known to those skilled in the art. In the description of this invention, it should be understood that terms such as "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, terms such as "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0032] like Figures 1 to 5As shown, the wastewater treatment system for the recycling of retired lithium iron phosphate batteries provided in this embodiment includes an acid-resistant ultrafiltration membrane device 100, a high-pressure reverse osmosis device 200, a reverse osmosis device 300, a mixer 400, a tubular membrane 500, an electrodialysis device 600, and a bipolar membrane electrodialysis device 700. The product water end of the acid-resistant ultrafiltration membrane device is connected to the inlet water end of the high-pressure reverse osmosis device 200, and the product water end of the high-pressure reverse osmosis device 200 is connected to the inlet water end of the reverse osmosis device 300. The mixer 400 has two inlets. The concentrated water end of the high-pressure reverse osmosis unit 200 is connected to the two inlet ends of the mixer 400, the outlet end of the mixer 400 is connected to the inlet end of the tubular membrane 500, the product water end of the tubular membrane 500 is connected to the inlet end of the electrodialysis unit 600, the concentrated water end of the electrodialysis unit 600 is connected to the inlet end of the bipolar membrane electrodialysis unit 700, the concentrated water end of the tubular membrane 500 is connected to the inlet end of the acid-resistant ultrafiltration membrane unit 100, and the desalination end of the electrodialysis unit 600 is connected to the inlet end of the reverse osmosis unit.

[0033] This embodiment also provides a method for treating wastewater from the recycling of retired lithium iron phosphate batteries, which uses the aforementioned wastewater treatment system for the recycling of retired lithium iron phosphate batteries and includes the following steps:

[0034] Wastewater from retired lithium iron phosphate batteries is fed into an acid-resistant ultrafiltration membrane unit 100 for ultrafiltration treatment to remove larger suspended solids, colloids, organic matter, and microorganisms. The permeate from the acid-resistant ultrafiltration membrane unit 100 is then fed into a high-pressure reverse osmosis unit 200 to separate solutes, ions, organic matter, microorganisms, and other impurities from the wastewater. The permeate from the high-pressure reverse osmosis unit 200 is further purified into a reverse osmosis unit 300 to obtain even purer water. The permeate from the reverse osmosis unit 300 is reused due to its high purity. The concentrated water from the high-pressure reverse osmosis unit 200 is mixed with flocculant and defluoridating agent in a mixer 400 to remove fluoride from the water and cause particles and suspended solids in the concentrated water to aggregate into larger particles. These larger particles are more easily retained by the tubular membrane 500, thus reducing fouling and clogging of the tubular membrane 500. After mixing, the effluent from mixer 400 enters tubular membrane 500. The concentrated water obtained from tubular membrane 500 is sent to acid-resistant ultrafiltration membrane unit 100 for further filtration. The permeate obtained from tubular membrane 500 is sent to electrodialysis unit 600 for ion concentration. The desalinated water obtained from electrodialysis unit 600 is sent to reverse osmosis unit 300 to obtain purified water. The concentrated water obtained from electrodialysis unit 600 is sent to bipolar membrane electrodialysis unit 700 for treatment to obtain sulfuric acid and sodium hydroxide. This process enables the resource utilization of wastewater from retired lithium iron phosphate batteries, yielding sulfuric acid, sodium hydroxide, and reclaimable water, with minimal byproduct wastewater generation.

[0035] Among them, the acid-resistant ultrafiltration membrane device 100 adopts a ceramic ultrafiltration membrane, a polytetrafluoroethylene ultrafiltration membrane, or a silicon carbide ultrafiltration membrane.

[0036] The mixer 400 includes a housing 1, a stirrer 2, a oscillating assembly 3, an inlet pipe 4, a venturi tube 5, a dosing assembly 6, a transmission assembly 7, a first rotating shaft 8, a first bearing seat 9, and an impeller 10. The inlet pipe 4 is fixedly connected to the upper part of both the left and right side walls of the housing 1. The outer end of the inlet pipe 4 is fixedly connected to the venturi tube 5. The venturi tube 5 is connected to the concentrate end of the high-pressure reverse osmosis device 200 via a pipe. The dosing end of the dosing assembly 6 is fixedly connected to the throat 5 of the venturi tube 5. At point 1, a first bearing seat 9 is fixed to the outer wall of the inlet pipe 4. The inner end of the first rotating shaft 8 passes through the first bearing seat 9 and the side wall of the inlet pipe 4, and extends into the interior of the inlet pipe 4 where an impeller 10 is fixed. The contact point between the first rotating shaft 8 and the inlet pipe 4 is sealed. The outer end of the first rotating shaft 8 is connected to the dosing assembly 6 via a transmission assembly 7. A swing assembly 3 is fixed to the top of the tank 1. An agitator 2 is fixed to the swing end of the swing assembly 3, and the agitator 2 extends into the interior of the tank 1. The mixer 400 achieves efficient mixing of wastewater with defluoridating agent and flocculant, improving the overall system treatment efficiency. The mixing operation is performed by the agitator 2. The swing assembly 3 drives the agitator 2 to swing, and the mixing is performed while swinging. This method results in more comprehensive mixing and higher mixing efficiency. In this embodiment, the dosing assembly 6 on the left contains defluoridating agent, and the dosing assembly 6 on the right contains flocculant. Taking the dosing on the left as an example, the dosing on the right is similar and will not be described in detail. A portion of the concentrated water from the high-pressure reverse osmosis unit 200 enters the venturi tube 5 on the left side through a pipe, and then enters the inlet pipe 4. The water flow drives the impeller 10 to rotate, which in turn drives the first rotating shaft 8 to rotate. Through the transmission assembly 7, the dosing assembly 6 performs intermittent dosing. The defluoridating agent enters from the throat 51 of the venturi tube 5, where it mixes rapidly with the wastewater and then enters the inlet pipe 4. The impeller 10 further enhances the mixing of the defluoridating agent and the wastewater. The impeller 10 not only further mixes the agent and wastewater but also drives the dosing assembly 6. The dosing of the inlet water and the agent is achieved through the venturi tube 5, allowing for rapid initial mixing of the wastewater and the agent. The dosing of the dosing assembly 6 does not require electricity but is hydraulically driven, which is energy-saving and environmentally friendly. Furthermore, by combining the impeller 10 with the inlet water flow, it achieves the effect of quantitative dosing on demand. The dosing amount matches the inlet water flow, resulting in excellent dosing effect without the need for additional quantitative dosing equipment.

[0037] The dosing assembly 6 includes a dosing pipe 61, a tank 62, a partition 63, a baffle 64, a connecting rod 65, a bracket 66, a first guide rod 67, a first guide sleeve 68, a second guide rod 69, a second guide sleeve 610, a contact block 611, a cam 612, a second bearing seat 613, and a second rotating shaft 614. The top of the throat 51 of the venturi tube 5 is fixedly connected to the tank 62, and the top of the dosing pipe 61 is fixedly connected to the tank 62. A partition 63 is fixedly installed in the lower part of the tank 62, and the partition 63 has a first through hole 615. First guide sleeves 68 are fixedly installed on both the left and right side walls of the tank 62. The inner end of the first guide rod 67 passes through the first guide sleeve 68 and the side wall of the tank 62, and extends into the interior of the tank 62 where a baffle 64 is fixedly installed. The top wall contacts the bottom wall of the partition 63. The baffle 64 has a second through hole 616. A second bearing seat 613 is fixed on the upper side wall of the box 1. The second rotating shaft 614 passes through the second bearing seat 613 and is connected to the first rotating shaft 8 through the transmission assembly 7. A cam 612 is fixed on the second rotating shaft 614. A bracket 66 is fixed on the top of the box 1. A second guide sleeve 610 is fixed on the top of the bracket 66. A second guide rod 69 passes through the second guide sleeve 610. A contact block 611 is fixed on the end of the second guide rod 69 near the cam 612 and the outer end of the first guide rod 67 near the cam 612. The end of the second guide rod 69 away from the cam 612 and the outer end of the first guide rod 67 away from the cam 612 are connected by a connecting rod 65. The transmission assembly 7 drives the second rotating shaft 614 to rotate, which in turn drives the cam 612 to rotate. When the distal end of the cam 612 rotates to the left contact block 611, it pushes the contact block 611 to move to the left. The first guide rod 67 on the right side of the baffle 64 pushes the baffle 64 to move to the left, so that the second through hole 616 on the baffle 64 is opposite to the first through hole 615 on the partition 63. The medicine passes through the first through hole 615 and the second through hole 616 and falls into the throat 51 of the venturi tube 5. The leftward movement of baffle 64 drives the leftward movement of the first guide rod 67, which in turn drives the leftward movement of the second guide rod 69 via connecting rod 65. This causes the rightward contact block 611 to move to the left. When the distal end of cam 612 rotates to the rightward contact block 611, it pushes the rightward contact block 611 to move to the right, causing the second guide rod 69 to move to the right and reset. This, in turn, drives the leftward movement of the first guide rod 67 of baffle 64 via connecting rod 65, causing baffle 64 to move to the right and reset. The first through hole 615 and the second through hole 616 no longer correspond, and baffle 64 blocks the first through hole 615, stopping the dosing. Thus, during water intake, the water flow continuously drives the impeller 10 to rotate, causing cam 612 to rotate continuously, intermittently achieving dosing. Based on the total water intake, the required total dosing amount can be calculated and stored in tank 62. Intermittent dosing avoids the concentration of chemicals caused by concentrated dosing, which is detrimental to subsequent mixing. Furthermore, the dosing amount can be adjusted according to the water intake flow rate.

[0038] The transmission assembly 7 includes a driving wheel 71, a driven wheel 72, and a transmission belt 73. The driving wheel 71 is fixed to the first rotating shaft 8, and the driven wheel 72 is fixed to the second rotating shaft 614. The driving wheel 71 and the driven wheel 72 are connected by the transmission belt 73. When the impeller 10 rotates, it drives the first rotating shaft 8 to rotate, causing the driving wheel 71 to rotate. This rotation of the driven wheel 72, via the transmission belt 73, causes the second rotating shaft 614 to rotate.

[0039] The oscillating assembly 3 includes an oscillating base 31, a connecting arm 32, and a left-right moving assembly 33. The stirrer 2 is fixed to the bottom of the oscillating end of the oscillating base 31. The connecting arm 32 is hinged to the left end of the moving end of the left-right moving assembly 33, and the left end of the connecting arm 32 is hinged to the top of the oscillating end of the oscillating base 31. The left-right moving assembly 33 drives the connecting arm 32 to move left and right, thus causing the oscillating end of the oscillating base 31 to oscillate left and right, thereby causing the stirrer 2 to oscillate left and right.

[0040] The left-right moving component 33 includes a column 331, a slide rail 332, a slider 333, a rack 334, a gear 335, a mounting bracket 336, a third bearing seat 3311, a worm gear 337, a worm 338, a third rotating shaft 339, and a forward / reverse motor 3310. A column 331 is fixed to the right side of the top of the housing 1. A slide rail 332 is fixed to the top of the column 331. A slider 333 is slidably connected to the top of the slide rail 332. A rack 334 is fixed to the top of the slider 333. The left side of the rack 334... The right end of the slide rail 332 is hinged to the connecting arm 32. A mounting bracket 336 is fixed to the top of the slide rail 332. A reversible motor 3310 and a third bearing seat 3311 are fixed to the inner top wall of the mounting bracket 336. A worm gear 338 is fixed to the bottom end of the reversible motor 3310. A third rotating shaft 339 passes through the third bearing seat 3311. A worm wheel 337 and a gear 335 are fixed to the third rotating shaft 339. The worm wheel 337 is located in front of the rack 334. The worm wheel 337 meshes with the worm gear 338, and the gear 335 meshes with the rack 334. When the reversible motor 3310 rotates, it drives the worm gear 338 to rotate, which in turn drives the worm wheel 337 to rotate, which in turn drives the third rotating shaft 339 to rotate, which in turn drives the gear 335 to rotate, which in turn drives the rack 334 to move, thus moving the connecting arm 32. Through the forward and reverse rotation of the reversible motor 3310, the rack 334 moves left and right, which in turn drives the connecting arm 32 to move left and right, thus enabling the swing seat 31 to operate. The worm gear 337 and worm 338 work together to ensure the fixed swing position. When the forward and reverse motor 3310 stops rotating after swinging a certain angle, the swing angle can still be guaranteed without any deviation.

[0041] The swing base 31 includes a hinge base 311, a swing arm 312, and a mounting plate 313. The lower part of the swing arm 312 is hinged to the hinge base 311, and the mounting plate 313 is fixed to the bottom of the swing arm 312. The stirrer 2 is fixed to the mounting plate 313. The upper part of the swing arm 312 is hinged to the left end of the connecting arm 32. When the connecting arm 32 moves left and right, it causes the upper part of the swing arm 312 to swing left and right, which in turn causes the lower part of the swing arm 312 to swing left and right, which in turn causes the mounting plate 313 to swing left and right, thus causing the stirrer 2 to swing left and right.

[0042] The bottom of the tank 1 is fixedly connected to a drain pipe 11, and a valve 12 is installed on the drain pipe 11. After the wastewater and the reagent are mixed, the valve 12 is opened, and the mixed wastewater is discharged through the drain pipe 11.

[0043] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wastewater treatment system for the recycling of retired lithium iron phosphate batteries, characterized in that: This includes acid-resistant ultrafiltration membrane devices, high-pressure reverse osmosis devices, reverse osmosis devices, mixers, tubular membranes, electrodialysis devices, and bipolar membrane electrodialysis devices; The product water end of the acid-resistant ultrafiltration membrane device is connected to the inlet water end of the high-pressure reverse osmosis device, and the product water end of the high-pressure reverse osmosis device is connected to the inlet water end of the reverse osmosis device. The mixer has two inlet ends, and the concentrate end of the high-pressure reverse osmosis device is connected to the two inlet ends of the mixer respectively. The outlet of the mixer is connected to the inlet of the tubular membrane, the product water end of the tubular membrane is connected to the inlet of the electrodialysis device, and the concentrate end of the electrodialysis device is connected to the inlet of the bipolar membrane electrodialysis device. The concentrate end of the tubular membrane is connected to the inlet end of the acid-resistant ultrafiltration membrane device, and the desalination end of the electrodialysis device is connected to the inlet end of the reverse osmosis device. The mixer includes a housing, a stirrer, a oscillating assembly, a water inlet pipe, a venturi tube, a dosing assembly, a transmission assembly, a first rotating shaft, a first bearing housing, and an impeller; Water inlet pipes are fixedly connected to the upper part of the left and right side walls of the box, and venturi tubes are fixedly connected to the outer ends of the water inlet pipes. The venturi tubes are connected to the concentrate end of the high-pressure reverse osmosis device through pipes. The dosing end of the dosing assembly is fixedly connected to the throat of the venturi tube; The outer wall of the water inlet pipe is fixed with a first bearing seat. The inner end of the first rotating shaft passes through the first bearing seat and the side wall of the water inlet pipe, and extends into the interior of the water inlet pipe where an impeller is fixed. The contact point between the first rotating shaft and the water inlet pipe is sealed. The outer end of the first rotating shaft is connected to the dosing assembly via a transmission assembly. A swing assembly is fixed to the top of the box, and a stirrer is fixed to the swing end of the swing assembly. The stirring end of the stirrer extends into the interior of the box. The dosing assembly includes a dosing pipe, a tank, a partition, a baffle, a connecting rod, a bracket, a first guide rod, a first guide sleeve, a second guide rod, a second guide sleeve, a contact block, a cam, a second bearing seat, and a second rotating shaft; The top of the throat of the Venturi tube is fixedly connected to the tank body, the top of the dosing tube is fixedly connected to the tank body, a partition is fixedly installed in the lower part of the tank body, and the partition has a first through hole. The left and right side walls of the tank are each fixed with a first guide sleeve. The inner end of the first guide rod passes through the first guide sleeve and the side wall of the tank, and extends into the inside of the tank where a baffle is fixed. The top wall of the baffle contacts the bottom wall of the partition, and the baffle has a second through hole. A second bearing seat is fixed above the side wall of the housing. The second rotating shaft passes through the second bearing seat and is connected to the first rotating shaft via the transmission assembly. A cam is fixed on the second rotating shaft. A bracket is fixed to the top of the housing, and a second guide sleeve is fixed to the top of the bracket. The second guide rod passes through the second guide sleeve. A contact block is fixed to the end of the second guide rod near the cam and the outer end of the first guide rod near the cam. The end of the second guide rod away from the cam and the outer end of the first guide rod away from the cam are connected by a connecting rod.

2. The wastewater treatment system for the recycling of retired lithium iron phosphate batteries according to claim 1, characterized in that: The acid-resistant ultrafiltration membrane device uses a ceramic ultrafiltration membrane, a polytetrafluoroethylene ultrafiltration membrane, or a silicon carbide ultrafiltration membrane.

3. The wastewater treatment system for the recycling of retired lithium iron phosphate batteries according to claim 1, characterized in that: The transmission assembly includes a driving wheel, a driven wheel, and a transmission belt; The driving wheel is fixed to the first rotating shaft, the driven wheel is fixed to the second rotating shaft, and the driving wheel and the driven wheel are connected by a transmission belt.

4. The wastewater treatment system for the recycling of retired lithium iron phosphate batteries according to claim 1, characterized in that: The swing assembly includes a swing base, a connecting arm, and a left-right movement assembly; The stirrer is fixed to the bottom of the swing end of the swing seat, and a connecting arm is hinged to the left end of the moving end of the left and right moving component. The left end of the connecting arm is hinged to the top of the swing end of the swing seat.

5. The wastewater treatment system for the recycling of retired lithium iron phosphate batteries according to claim 4, characterized in that: The left and right moving components include a column, a slide rail, a slider, a rack, a gear, a mounting bracket, a third bearing seat, a worm gear, a worm, a third rotating shaft, and a forward and reverse motor; A column is fixed to the right side of the top of the box, a slide rail is fixed to the top of the column, a slider is slidably connected to the top of the slide rail, a rack is fixed to the top of the slider, and the left end of the rack is hinged to the right end of the connecting arm. A mounting bracket is fixed to the top of the slide rail. A reversible motor and a third bearing seat are fixed to the inner top wall of the mounting bracket. A worm is fixed to the bottom end of the reversible motor. The third rotating shaft passes through the third bearing seat. The worm wheel and gear are fixed to the third rotating shaft. The worm wheel is located in front of the rack. The worm wheel meshes with the worm and the gear meshes with the rack.

6. The wastewater treatment system for the recycling of retired lithium iron phosphate batteries according to claim 4, characterized in that: The swing seat includes a hinge seat, a swing arm, and a mounting plate; The lower part of the swing arm is hinged to the hinge seat, the bottom of the swing arm is fixed with a mounting plate, the stirrer is fixed to the mounting plate, and the upper part of the swing arm is hinged to the left end of the connecting arm.

7. The wastewater treatment system for the recycling of retired lithium iron phosphate batteries according to claim 1, characterized in that: A drain pipe is fixedly connected to the bottom of the box, and a valve is installed on the drain pipe.

8. A method for treating wastewater from the recycling of retired lithium iron phosphate batteries, characterized in that, The wastewater treatment system for the recycling of retired lithium iron phosphate batteries according to any one of claims 1-7 is used for treatment, including the following steps: Wastewater from retired lithium iron phosphate batteries is fed into an acid-resistant ultrafiltration membrane unit for ultrafiltration treatment. The permeate from the acid-resistant ultrafiltration membrane unit is then fed into a high-pressure reverse osmosis unit. The permeate from the high-pressure reverse osmosis unit is then fed into the reverse osmosis unit. The permeate from the reverse osmosis unit is reused. The concentrated water from the high-pressure reverse osmosis unit is mixed with flocculant and defluorinating agent in a mixer. After mixing, the effluent from the mixer enters a tubular membrane. The concentrated water from the tubular membrane is then fed into an acid-resistant ultrafiltration membrane unit. The permeate from the tubular membrane is then fed into an electrodialysis unit. The desalinated water from the electrodialysis unit is then fed into the reverse osmosis unit. The concentrated water from the electrodialysis unit is then fed into a bipolar membrane electrodialysis unit for treatment to obtain sulfuric acid and sodium hydroxide.

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