Lithium battery waste processing device and method for preparing high-purity lithium dihydrogen phosphate

Abstract

This invention provides a lithium battery waste processing device and a method for preparing high-purity lithium dihydrogen phosphate. It relates to the field of metal material recycling. The lithium battery waste processing device includes a substrate. The device and method provide efficient crushing and sieving of waste lithium batteries using a first and second crushing wheel in a crushing chamber, along with a screen, separates black powder containing positive electrode active material, ensuring the fineness of the raw materials for subsequent leaching reactions. Hydrogen peroxide and dilute sulfuric acid are added to the leaching tank for acid leaching. Simultaneously, a stirring motor drives stirring blades to mix the black powder and solution. An annular plate and several defoaming plates are installed on the stirring shaft to slowly rotate and break up foam, preventing foam accumulation from affecting reaction efficiency and liquid-solid contact, thus improving the leaching rate. Finally, a transfer pump and a plate and frame filter press are used to transfer the mixture and separate the solid and liquid components. The lithium-containing solution is directly obtained from the collection tank, resulting in high recovery efficiency.

Description

Technical Field

[0001] This invention relates to the field of metal material recycling, and in particular to a lithium battery waste processing device and a method for preparing high-purity lithium dihydrogen phosphate. Background Technology

[0002] Lithium dihydrogen phosphate (LDH) is a key precursor for the preparation of lithium iron phosphate (LFP), a cathode material for lithium-ion batteries. It can also be used in fields such as optics and chemical catalysis. With the rapid development of the new energy industry, the demand for high-purity LDH is increasing. The preparation of LDH requires the use of lithium-rich liquid. As the production and ownership of new energy vehicles continue to rise, power batteries will reach their peak of obsolescence in the coming years. The global volume of scrapped lithium-ion batteries is gradually increasing, and the disposal of these scrapped batteries has become an issue that cannot be ignored. Lithium-rich liquid can be obtained by leaching and recycling the waste lithium batteries in a lithium battery waste processing device.

[0003] Existing lithium battery waste processing equipment involves disassembling the outer casing, crushing it in a shredder, then placing it in a leaching tank with sulfuric acid solution for lithium leaching, and finally obtaining a lithium-rich solution through solid-liquid separation.

[0004] However, existing lithium battery waste processing equipment generates foam when sulfuric acid is added during the leaching process, and the accumulation of foam affects the leaching efficiency.

[0005] Therefore, it is necessary to provide a lithium battery waste processing device and a method for preparing high-purity lithium dihydrogen phosphate to solve the above-mentioned technical problems. Summary of the Invention

[0006] This invention provides a lithium battery waste processing device and a method for preparing high-purity lithium dihydrogen phosphate, which solves the problem that foam is generated when sulfuric acid is added during the leaching process, and the foam accumulation affects the leaching efficiency.

[0007] To solve the above-mentioned technical problems, the present invention provides a lithium battery waste processing device, comprising: a substrate;

[0008] The leaching mechanism is fixedly installed on the top of the substrate. The leaching mechanism includes a leaching tank, which is fixedly installed on the top of the substrate. A stirring motor is fixedly installed on the top of the leaching tank. A stirring shaft is fixedly installed on the output shaft of the stirring motor. The bottom end of the stirring shaft passes through the top of the leaching tank and extends into the interior. Several stirring blades are fixedly installed on the surface of the stirring shaft inside the leaching tank. A vertical groove is opened inside the stirring shaft. A water supply pipe is connected to the top of the leaching tank. A circular hole is opened on the top of the leaching tank.

[0009] A crushing mechanism, which is fixedly mounted on the top of the substrate;

[0010] A transfer mechanism, which is fixedly mounted on the top of the substrate;

[0011] The defoaming mechanism is rotatably mounted on the surface of the stirring shaft via a bearing seat. The defoaming mechanism includes a defoaming ring and an annular plate. The defoaming ring is rotatably mounted on the surface of the stirring shaft via a bearing seat. Several defoaming plates are fixedly mounted on the circumferential side of the defoaming ring. Two fixing columns are symmetrically fixedly mounted on the top of the defoaming ring. The interior of the annular plate is slidably mounted to the interior of the vertical groove via a cylinder. Two insertion holes are symmetrically opened on the surface of the annular plate, and the two insertion holes are respectively adapted to the two fixing columns for installation.

[0012] A plate and frame filter press, wherein the plate and frame filter press is fixedly installed on the top of the substrate;

[0013] The two collection boxes are fixedly installed on the top of the substrate and are adapted to the outlet end of the plate and frame filter press.

[0014] Preferably, the pulverizing mechanism includes a pulverizing chamber, with two pillars fixedly mounted on the top of the substrate on each side of the pulverizing chamber. A first pulverizing shaft and a second pulverizing shaft are rotatably mounted inside the pulverizing chamber. One end of each of the first and second pulverizing shafts penetrates the inner wall of the pulverizing chamber and extends to the outside. A plurality of first pulverizing wheels and a plurality of second pulverizing wheels are fixedly mounted on the inner surfaces of the first and second pulverizing shafts, respectively, and the first and second pulverizing wheels are fitted together. A first gear and a second gear are fixedly mounted on the outer ends of the first and second pulverizing shafts, respectively, with the first gear meshing with the second gear. A pulverizing motor is fixedly mounted on one side of the pulverizing chamber via a support plate. The output shaft of the pulverizing motor is fixedly connected to the outer end of the first pulverizing shaft. A screen is fixedly mounted on the bottom of the pulverizing chamber, and a pulverizing funnel is fixedly mounted on the bottom of the screen. The bottom end of the pulverizing funnel communicates with the top of the leaching tank.

[0015] Preferably, the transfer mechanism includes a transfer pump, which is fixedly installed on the top of the substrate. The input end of the transfer pump is connected to the bottom of the leaching tank through a transfer pipe, and the output end of the transfer pump is connected to a riser pipe. The end of the riser pipe is connected to the input end of the plate and frame filter press.

[0016] Preferably, a collection mechanism is fixedly installed on the top of the substrate. The collection mechanism includes a collection pump, which is fixedly installed on the top of the substrate. The input end of the collection pump is connected to a collection pipe, and the two ends of the collection pipe pass through one side of the two collection boxes and extend into the interior. The output end of the collection pump is connected to a discharge pipe.

[0017] Preferably, a cleaning mechanism is fixedly installed on the top of the substrate. The cleaning mechanism includes a cleaning tank, which is fixedly installed on the top of the substrate. The top of the cleaning tank is connected to a feed funnel, and the bottom of the cleaning tank is connected to a discharge pump through a connecting pipe. The output end of the discharge pump is connected to a discharge pipe, and the end of the discharge pipe is connected to the top of the cleaning tank.

[0018] Preferably, a solid-liquid separator is fixedly mounted on the top of the substrate, and the end of the discharge pipe is connected to the feed end of the solid-liquid separator.

[0019] Preferably, the outlet of the solid-liquid separator is connected to a concentration mechanism via a connecting pipe. The concentration mechanism includes a concentration pump and a concentration tank. The concentration pump is connected to the outlet of the solid-liquid separator via a connecting pipe. The output end of the concentration pump is connected to a concentration pipe. The concentration tank is fixedly installed on the top of the base plate. The end of the concentration pipe is connected to the top of the concentration tank. The bottom of the concentration tank is provided with a rotating cover via a drain pipe.

[0020] Preferably, a sulfuric acid mechanism is fixedly installed on the top of the leaching tank. The sulfuric acid mechanism includes a sulfuric acid tank, which is fixedly installed on the top of the leaching tank. An acid addition pipe is connected to the top of the sulfuric acid tank, and an outer pipe is connected to the bottom of the sulfuric acid tank. The bottom end of the outer pipe passes through the circular hole and extends into the interior of the leaching tank. An inner pipe is slidably installed inside the outer pipe. Two floats are fixedly installed on the outer wall of the inner pipe via float plates. Two abutments are symmetrically fixedly installed on the outer wall of the inner pipe. Two sliding grooves are symmetrically opened on the surface of the outer pipe. The two abutments are slidably connected to the two sliding grooves. A switch plate is fixedly installed on the surface of the outer pipe. A switch is fixedly installed at the bottom of the switch plate and is adapted to the abutments. An opening and closing plate is rotatably installed on the bottom of the inner wall of the sulfuric acid tank via a rotating base and is adapted to the outer pipe.

[0021] Preferably, a cylinder is fixedly installed on the top of the inner wall of the leaching tank, a bearing plate is fixedly installed on the output end of the cylinder, two bearing columns are fixedly installed on the top of the bearing plate, and an annular groove is opened on the top of the annular plate, with the two bearing columns being adapted to the annular groove.

[0022] A method for preparing high-purity lithium dihydrogen phosphate includes the following steps:

[0023] S1: Extraction: The lithium-rich solution is extracted using an organic phase containing an extractant and a diluent to obtain an organic phase loaded with lithium;

[0024] S2: Phosphoric acid back-extraction: Using phosphoric acid solution as a back-extraction agent, the lithium-loaded organic phase obtained in S1 is back-extracted to obtain a back-extraction mixture containing lithium dihydrogen phosphate and phosphoric acid, and a regenerated organic phase is obtained.

[0025] S3: Concentration and crystallization: The back-extraction mixture obtained in S2 is evaporated and concentrated, cooled and crystallized, and the solid and liquid are separated to obtain crude lithium dihydrogen phosphate.

[0026] S4: Refining: The crude lithium dihydrogen phosphate is recrystallized or washed and dried to obtain a high-purity lithium dihydrogen phosphate product.

[0027] Compared with related technologies, the lithium battery waste processing device provided by the present invention has the following beneficial effects:

[0028] This invention provides a lithium battery waste processing device. Through the combination of a first and second crushing wheel in the crushing chamber and a screen, waste lithium batteries can be efficiently crushed and screened to extract black powder containing positive electrode active material, ensuring the fineness of the raw materials for subsequent leaching reactions. Hydrogen peroxide and dilute sulfuric acid are added to the leaching tank for acid leaching. Simultaneously, a stirring motor drives stirring blades to mix the black powder and solution. An annular plate and several defoaming plates are installed on the stirring shaft to slowly rotate and break up foam, preventing foam accumulation from affecting reaction efficiency and liquid-solid contact, thus improving the leaching rate. Finally, a transfer pump and a plate and frame filter press are used to transfer the mixture and separate the solid and liquid components. The lithium-containing solution is directly obtained from the collection tank, resulting in high recovery efficiency. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a preferred embodiment of a lithium battery waste processing device provided by the present invention;

[0030] Figure 2 for Figure 1 The diagram shows the structure of the leaching mechanism.

[0031] Figure 3 for Figure 1 The diagram shows the structure of the crushing mechanism.

[0032] Figure 4 for Figure 1 The diagram shows the structure of the transfer mechanism.

[0033] Figure 5 for Figure 2 The enlarged schematic diagram of part A shown below;

[0034] Figure 6 This is a schematic diagram of the structure of a second embodiment of a lithium battery waste processing device;

[0035] Figure 7 for Figure 6 The diagram shows the installation of the sulfuric acid processing unit;

[0036] Figure 8 for Figure 6 The diagram shows the structure of the collection mechanism.

[0037] Figure 9 for Figure 6 The diagram shows the structure of the impurity removal mechanism.

[0038] Figure 10 for Figure 6 The diagram shows the structure of the concentration mechanism.

[0039] Figure 11 for Figure 10 Another schematic diagram of the concentration mechanism shown;

[0040] Figure 12 for Figure 7 The diagram shows the structure of the sulfuric acid mechanism.

[0041] Figure 13 for Figure 7 The diagram shows the installation of the support plate.

[0042] Figure 14 for Figure 13 The diagram shows the installation of the load-bearing column;

[0043] Figure 15 This is a process flow diagram for preparing high-purity lithium dihydrogen phosphate.

[0044] Numbered in the diagram: 1. Substrate; 2. Leaching mechanism; 201. Leaching tank; 202. Stirring motor; 203. Stirring shaft; 204. Stirring blade; 205. Water supply pipe; 206. Vertical groove; 207. Circular hole; 3. Crushing mechanism; 301. Crushing box; 302. First crushing shaft; 303. First crushing wheel; 304. First gear; 305. Second crushing shaft; 306. Second crushing wheel; 307. Second gear; 308. Crushing motor; 309. Screen; 310. Crushing funnel; 4. Transfer mechanism; 401. Transfer pipe; 402. Transfer pump; 403. Lifting pipe; 5. Defoaming mechanism; 501. Defoaming ring; 502. Defoaming plate; 503. Fixed column; 504. Annular plate; 505. Insertion hole; 6. 7. Collection mechanism: 601. Collection pump; 602. Collection pipe; 603. Discharge pipe; 7. Impurity removal mechanism: 701. Impurity removal tank; 702. Feed funnel; 703. Discharge pump; 704. Discharge pipe; 8. Concentration mechanism: 801. Concentration pump; 802. Concentration pipe; 803. Concentration tank; 804. Rotating cover; 9. Sulfuric acid mechanism: 901. Sulfuric acid tank; 902. Acid addition pipe; 903. Outer pipe; 904. Inner pipe; 905. Float plate; 906. Float; 907. Switch plate; 908. Switch; 909. Support column; 910. Opening and closing plate; 911. Slide chute; 10. Plate and frame filter press; 11. Collection box; 12. Cylinder; 13. Solid-liquid separator; 14. Support plate; 15. Support column; 16. Annular trough. Detailed Implementation

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0046] A lithium battery waste processing device

[0047] First Embodiment

[0048] Please refer to the following: Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 A lithium battery waste processing device includes: a substrate 1;

[0049] The leaching mechanism 2 is fixedly installed on the top of the substrate 1. The leaching mechanism 2 includes a leaching tank 201, which is fixedly installed on the top of the substrate 1. A stirring motor 202 is fixedly installed on the top of the leaching tank 201. A stirring shaft 203 is fixedly installed on the output shaft of the stirring motor 202. The bottom end of the stirring shaft 203 passes through the top of the leaching tank 201 and extends into the interior. Several stirring blades 204 are fixedly installed on the surface of the stirring shaft 203 inside the leaching tank 201. A vertical groove 206 is opened inside the stirring shaft 203. A water supply pipe 205 is connected to the top of the leaching tank 201. A circular hole 207 is opened on the top of the leaching tank 201.

[0050] Crushing mechanism 3 is fixedly installed on the top of the substrate 1;

[0051] Transfer mechanism 4, which is fixedly installed on the top of the substrate 1;

[0052] The defoaming mechanism 5 is rotatably mounted on the surface of the stirring shaft 203 via a bearing seat. The defoaming mechanism 5 includes a defoaming ring 501 and an annular plate 504. The defoaming ring 501 is rotatably mounted on the surface of the stirring shaft 203 via a bearing seat. Several defoaming plates 502 are fixedly mounted on the circumferential side of the defoaming ring 501. Two fixing posts 503 are symmetrically fixedly mounted on the top of the defoaming ring 501. The interior of the annular plate 504 is slidably mounted to the interior of the vertical groove 206 via a cylinder. Two insertion holes 505 are symmetrically opened on the surface of the annular plate 504. The two insertion holes 505 are respectively adapted to the two fixing posts 503 for installation.

[0053] Plate and frame filter press 10, which is fixedly installed on the top of the base plate 1;

[0054] Collection box 11, two collection boxes 11 are fixedly installed on the top of the base plate 1, and the two collection boxes 11 are adapted to the water outlet end of the plate and frame filter press 10.

[0055] The pulverizing mechanism 3 includes a pulverizing box 301. The pulverizing box 301 is fixedly mounted to the top of the base plate 1 on both sides by two support pillars. A first pulverizing shaft 302 and a second pulverizing shaft 305 are rotatably mounted inside the pulverizing box 301. One end of each of the first pulverizing shaft 302 and the second pulverizing shaft 305 penetrates the inner wall of the pulverizing box 301 and extends to the outside. A plurality of first pulverizing wheels 303 and a plurality of second pulverizing wheels 306 are fixedly mounted on the surfaces of the first pulverizing shaft 302 and the second pulverizing shaft 305 located inside the pulverizing box 301. The first pulverizing wheels 303 and the second pulverizing wheels 306 are fitted together. A first gear 304 and a second gear 307 are respectively fixedly installed at one end of the first crushing shaft 302 and the second crushing shaft 305 located outside the crushing box 301. The first gear 304 meshes with the second gear 307. A crushing motor 308 is fixedly installed on one side of the crushing box 301 through a support plate. The output shaft of the crushing motor 308 is fixedly connected to the end of the first crushing shaft 302 located outside the crushing box 301. A screen 309 is fixedly installed at the bottom of the crushing box 301. A crushing funnel 310 is fixedly installed at the bottom of the screen 309. The bottom end of the crushing funnel 310 is connected to the top of the leaching tank 201.

[0056] The transfer mechanism 4 includes a transfer pump 402, which is fixedly installed on the top of the substrate 1. The input end of the transfer pump 402 is connected to the bottom of the leaching tank 201 through a transfer pipe 401. The output end of the transfer pump 402 is connected to a lifting pipe 403, and the end of the lifting pipe 403 is connected to the input end of the plate and frame filter press 10.

[0057] In actual use, the center of the defoaming plate 502 is located at the plane where the foam and the liquid surface intersect.

[0058] The working principle of the lithium battery waste processing device provided by this invention is as follows:

[0059] First, the disassembled and discharged waste lithium batteries are manually placed into the crushing box 301. The crushing motor 308 is started to drive the first crushing shaft 302 to rotate. The first gear 304 meshes with the second gear 307, and the second crushing shaft 305 rotates accordingly. The waste lithium batteries are crushed by the first crushing wheel 303 and the second crushing wheel 306. The black powder containing positive electrode active material falls into the crushing funnel 310 after passing through the screen 309 and enters the interior of the leaching tank 201.

[0060] Then, hydrogen peroxide is added manually through water pipe 205 for reduction, and dilute sulfuric acid solution is added through round hole 207 for acid leaching. The stirring motor 202 is started to drive the stirring blade 204 to stir the black powder and solution. During the mixing process, bubbles are generated and accumulate on the liquid surface to form foam. At this time, the stirring motor 202 rotates slowly, and the annular plate 504 slidingly installed on the stirring shaft 203 drives several defoaming plates 502 to rotate, eliminating the foam.

[0061] Finally, after stirring is completed, the transfer pump 402 is started to extract the mixture through the transfer pipe 401 and input it into the plate and frame filter press 10 through the riser pipe 403. After solid-liquid separation, the lithium-containing solution is collected by the collection tank 11.

[0062] Compared with related technologies, the lithium battery waste processing device provided by the present invention has the following beneficial effects:

[0063] By using the first crushing wheel 303 and the second crushing wheel 306 in the crushing box 301 in conjunction with the screen 309, the waste lithium battery can be efficiently crushed and screened to separate the black powder containing positive electrode active material, ensuring the fineness of the raw materials for the subsequent leaching reaction. Hydrogen peroxide and dilute sulfuric acid are added to the leaching tank 201 for acid leaching. At the same time, the stirring motor 202 drives the stirring blade 204 to mix the black powder and the solution. An annular plate 504 and several defoaming plates 502 are set on the stirring shaft 203. The foam is broken by slow rotation, avoiding foam accumulation that affects the reaction efficiency and liquid-solid contact, thereby improving the leaching rate. Finally, the mixed liquid is transferred and the solid-liquid separation is achieved by the transfer pump 402 and the plate and frame filter press 10. The lithium-containing solution is directly obtained from the collection box 11, resulting in high recovery efficiency.

[0064] Second Embodiment

[0065] Please refer to the following: Figures 6-14 Based on the lithium battery waste processing apparatus provided in the first embodiment of this application, the second embodiment of this application proposes another lithium battery waste processing apparatus. The second embodiment is merely a preferred embodiment of the first embodiment, and the implementation of the second embodiment will not affect the separate implementation of the first embodiment.

[0066] Specifically, the difference in the lithium battery waste processing device provided in the second embodiment of this application is that a collection mechanism 6 is fixedly installed on the top of the substrate 1. The collection mechanism 6 includes a collection pump 601, which is fixedly installed on the top of the substrate 1. The input end of the collection pump 601 is connected to a collection pipe 602. The two ends of the collection pipe 602 pass through one side of the two collection boxes 11 and extend into the interior. The output end of the collection pump 601 is connected to a discharge pipe 603.

[0067] A cleaning mechanism 7 is fixedly installed on the top of the substrate 1. The cleaning mechanism 7 includes a cleaning tank 701, which is fixedly installed on the top of the substrate 1. The top of the cleaning tank 701 is connected to a feed funnel 702, and the bottom of the cleaning tank 701 is connected to a discharge pump 703 through a connecting pipe. The output end of the discharge pump 703 is connected to a discharge pipe 704, and the end of the discharge pipe 603 is connected to the top of the cleaning tank 701.

[0068] A solid-liquid separator 13 is fixedly installed on the top of the substrate 1, and the end of the discharge pipe 704 is connected to the feed end of the solid-liquid separator 13.

[0069] The outlet of the solid-liquid separator 13 is connected to a concentration mechanism 8 via a connecting pipe. The concentration mechanism 8 includes a concentration pump 801 and a concentration tank 803. The concentration pump 801 is connected to the outlet of the solid-liquid separator 13 via a connecting pipe. The output end of the concentration pump 801 is connected to a concentration pipe 802. The concentration tank 803 is fixedly installed on the top of the base plate 1. The end of the concentration pipe 802 is connected to the top of the concentration tank 803. The bottom of the concentration tank 803 is provided with a rotating cover 804 via a drain pipe.

[0070] A sulfuric acid mechanism 9 is fixedly installed on the top of the leaching tank 201. The sulfuric acid mechanism 9 includes a sulfuric acid tank 901, which is fixedly installed on the top of the leaching tank 201. An acid addition pipe 902 is connected to the top of the sulfuric acid tank 901, and an outer pipe 903 is connected to the bottom of the sulfuric acid tank 901. The bottom end of the outer pipe 903 passes through the circular hole 207 and extends into the interior of the leaching tank 201. An inner pipe 904 is slidably installed inside the outer pipe 903, and two floats 906 are fixedly installed on the outer wall of the inner pipe 904 by float plates 905. Two abutments 909 are symmetrically fixedly installed on the outer wall of the inner tube 904. Two sliding grooves 911 are symmetrically opened on the surface of the outer tube 903. The two abutments 909 are slidably connected to the two sliding grooves 911. A switch plate 907 is fixedly installed on the surface of the outer tube 903. A switch 908 is fixedly installed at the bottom of the switch plate 907. The switch 908 is adapted to the abutments 909. An opening and closing plate 910 is rotatably installed at the bottom of the inner wall of the sulfuric acid tank 901 through a rotating base. The opening and closing plate 910 is adapted to the outer tube 903.

[0071] A cylinder 12 is fixedly installed on the top of the inner wall of the leaching tank 201. A bearing plate 14 is fixedly installed on the output end of the cylinder 12. Two bearing columns 15 are fixedly installed on the top of the bearing plate 14. An annular groove 16 is opened on the top of the annular plate 504. The two bearing columns 15 are adapted to the annular groove 16.

[0072] In actual use, the dilute sulfuric acid solution in the sulfuric acid tank 901 is not full; the buoyancy of the float 906 is greater than the weight of the dilute sulfuric acid solution inside the sulfuric acid tank 901; when the inner tube 904 pushes the opening and closing plate 910 to open, it is limited by the abutment 909 and the slide groove 911 to ensure that the opening angle of the opening and closing plate 910 is less than 90° so as to facilitate automatic closing.

[0073] The working principle of the lithium battery waste processing device provided in this embodiment is as follows:

[0074] First, two collection tanks 11 collect lithium-containing solutions. The lithium-containing solution is then drawn out through collection pipe 602 by the collection pump 601 and discharged into the impurity removal tank 701 through discharge pipe 603. Iron powder is manually added through feed funnel 702 to extract copper from the black powder. After extraction, the solution is drawn out through discharge pump 703 and discharged into solid-liquid separator 13 through discharge pipe 704 for solid-liquid separation. Finally, the separated liquid enters the concentration tank 803. The heating wire inside the concentration tank 803 is activated for heating and concentration. Finally, the high-purity lithium-rich liquid is collected by opening the rotating cover 804.

[0075] When foam is generated, the large amount of accumulated foam pushes the two floats 906 to rise. The floats 906 drive the inner tube 904 to rise. After the inner tube 904 rises, it pushes the opening and closing plate 910 to open. At this time, the inner tube 904 is separated from the foam and quantitatively discharges dilute sulfuric acid solution into the interior of the leaching tank 201.

[0076] At the same time, the inner tube 904 rises, causing the stop column 909 to rise. While the stop column 909 is limiting the inner tube 904, it also contacts the switch 908. The switch 908 is only contacted when the stop column 909 rises to its highest point, which indicates that the foam has accumulated to the point where it needs to be cleaned.

[0077] At this point, the float 906 is not at the same level as the defoaming plate 502. Switch 908 starts cylinder 12, which drives the annular plate 504 to be inserted into the fixed column 503 through the insertion hole 505. At this time, the stirring motor 202 starts to slowly defoam. After defoaming, the float 906 descends and defoaming stops. At this time, the float 906 enters between the two defoaming plates 502 without direct contact. The opening and closing plate 910 closes automatically. Dilute sulfuric acid is added to the sulfuric acid tank 901 through the acid adding pipe 902. Cylinder 12 causes the annular plate 504 to detach from the fixed column 503 through the bearing column 15. At this time, the stirring motor 202 stirs the dilute sulfuric acid, black powder and hydrogen peroxide solution normally. The opening and closing plate 910 is opened by the increase of foam to achieve automatic defoaming. The defoaming work is stopped by the elimination of foam. At the same time, the dilute sulfuric acid is added quantitatively. The inner tube 904 rises away from the foam to add sulfuric acid, avoiding foam interference that may cause local overconcentration.

[0078] When foam is generated again, the above workflow can be performed automatically.

[0079] Compared with related technologies, the lithium battery waste processing device provided in this embodiment has the following beneficial effects:

[0080] When a large amount of foam accumulates, it pushes the float 906 upward, causing the inner tube 904 to rise. On one hand, the opening and closing plate 910 automatically opens to add a measured amount of dilute sulfuric acid solution to the leaching tank 201. Simultaneously, acid is added after the inner tube 904 moves away from the foam layer to avoid foam interference and localized over-concentration. On the other hand, the rising inner tube 904 is limited by the stop column 909 and simultaneously triggers the switch 908, activating the cylinder 12 to drive the annular plate 504 to insert into the fixed column 503. Then, the stirring motor 202 is activated to slowly and mechanically defoam, avoiding contact with the float 906. This achieves automated and precise defoaming triggered by foam. After defoaming is complete, the float 906 automatically descends, the opening and closing plate 910 closes, the cylinder 12 drives the annular plate 504 to detach from the fixed column 503, and the stirring motor 202 resumes normal stirring. Simultaneously, dilute sulfuric acid is automatically replenished to the sulfuric acid tank 901 via the acid addition pipe 902, awaiting the next defoaming requirement. This effectively avoids the interference of foam accumulation on the leaching reaction, improves the lithium leaching efficiency, and enables the quantitative addition of dilute sulfuric acid as needed, reducing reagent waste. Subsequently, the lithium-containing solution is transported to the impurity removal tank 701 via the collection pump 601, where copper is extracted by iron powder displacement. After separation by the solid-liquid separator 13, it enters the concentration tank 803 for heating and concentration, ultimately obtaining a high-purity lithium-rich solution. Automatic defoaming is achieved by opening the opening and closing plate 910 when foam increases, and the defoaming work is stopped when the foam is eliminated. At the same time, the quantitative addition of dilute sulfuric acid is completed. The entire process has a high degree of automation, stable operation, significantly improved recovery efficiency, and reduced labor costs and material consumption.

[0081] A method for preparing high-purity lithium dihydrogen phosphate includes the following steps:

[0082] S1: Extraction: The lithium-rich solution is the leachate from the recycling of waste lithium batteries as the aqueous phase raw material. It is extracted with an organic phase containing extractant and diluent to obtain an organic phase loaded with lithium.

[0083] S2: Phosphoric acid back-extraction: Using phosphoric acid solution as the back-extraction agent, the lithium-loaded organic phase obtained in S1 is back-extracted to obtain a back-extraction mixture containing lithium dihydrogen phosphate and phosphoric acid, and a regenerated organic phase is obtained. The reactions that occur during the back-extraction process are as follows:

[0084]

[0085] The concentration of phosphoric acid is 1 mol / L to 8 mol / L, the back-extraction ratio (O / A) is (1:1) to (10:1), and the number of back-extraction stages is 1 to 5.

[0086] S3: Concentration and crystallization: The back-extraction mixture obtained in S2 is evaporated and concentrated, cooled and crystallized, and the solid and liquid are separated to obtain crude lithium dihydrogen phosphate.

[0087] S4: Refining: The crude lithium dihydrogen phosphate is recrystallized or washed and dried to obtain a high-purity lithium dihydrogen phosphate product.

[0088] In practical use, the extractant is a neutral phosphorus extractant, preferably tributyl phosphate (TBP), triisobutyl phosphate (TiBP), or trioctylphosphine oxide (TOPO); the diluent is sulfonated kerosene, solvent oil, or aromatic solvent; the volume fraction of the extractant in the organic phase is 30%–70%, the volume fraction of the diluent is 30%–70%, and a phase modifier may be added; in step S2, the back-extraction temperature is 20℃–60℃, the back-extraction time is 5–30 minutes, and the regenerated organic phase obtained from the back-extraction is returned to step S1 for recycling; in step S3, the evaporation and concentration temperature is 60℃–100℃, and the crystallization temperature is 0℃–30℃; the lithium-rich solution is an aqueous solution containing lithium ions, and can also be lithium extraction mother liquor from salt lake brine or lithium-containing solutions from lithium ore processing.

[0089] First Embodiment

[0090] Composition of lithium-rich solution: The residual liquid from nickel-cobalt extraction, taken from a waste lithium battery recycling plant, has a lithium ion concentration of 2.5 g / L, a sulfate concentration of 15 g / L, a sodium ion concentration of 1.2 g / L, and a calcium ion concentration of 150 mg / L.

[0091] Resin calcium removal: HP404 resin was used to remove calcium from the lithium-rich solution first. The pH of the lithium-rich solution was adjusted to approximately 8.2-8.5 by adding ammonia dropwise, and then the solution was slowly passed through the resin column. A calcium-removed lithium-rich solution was obtained with a concentration of 0.94 mg / L.

[0092] Extraction: The organic phase composition was 50% TBP + 50% sulfonated kerosene (volume ratio), the extraction ratio was O / A = 2:1, the extraction stage was 3 stages, the lithium extraction rate was 98.5%, and a lithium-loaded organic phase was obtained.

[0093] Phosphoric acid back-extraction: A 4 mol / L phosphoric acid solution was used as the back-extraction agent. The back-extraction ratio O / A = 3:1, with two back-extraction stages, a back-extraction temperature of 25℃, and a back-extraction time of 10 minutes. After back-extraction, the lithium concentration in the organic phase decreased to 0.03 g / L, and the lithium ion concentration in the back-extraction mixture was 7.2 g / L. The main components were... and excessive .

[0094] Concentration and crystallization: The back-extraction mixture is evaporated and concentrated at 80°C to a lithium concentration of about 30 g / L, cooled to 10°C to crystallize, and filtered to obtain crude lithium dihydrogen phosphate.

[0095] Refining: The crude product is recrystallized with a small amount of pure water and dried to obtain lithium dihydrogen phosphate product.

[0096] Product testing: Lithium dihydrogen phosphate content 99.6%, sulfate content 28ppm, sodium content 15ppm, calcium content 5ppm, meeting the battery-grade lithium dihydrogen phosphate standard.

[0097] Second Embodiment

[0098] Composition of lithium-rich solution: Lithium precipitation mother liquor taken from a lithium carbonate production line, with lithium ion concentration of 2.6 g / L, sulfate concentration of 196 g / L, sodium ion concentration of 65 g / L, and calcium ion concentration of 277 mg / L.

[0099] Resin calcium removal: HP404 resin was used to remove calcium from the lithium-rich solution first. The pH of the lithium-rich solution was adjusted to approximately 8.2-8.5 by adding ammonia dropwise, and then the solution was slowly passed through the resin column. A calcium-free lithium-rich solution was obtained with a concentration of 1.1 mg / L.

[0100] Extraction: The organic phase composition was 50% TBP + 50% sulfonated kerosene (volume ratio), the extraction ratio was O / A = 2:1, the extraction stage was 3 stages, the lithium extraction rate was 99.2%, and a lithium-loaded organic phase was obtained.

[0101] Phosphoric acid back-extraction: A 4 mol / L phosphoric acid solution was used as the back-extraction agent. The back-extraction ratio (O / A) was 3:1, with two back-extraction stages. The back-extraction temperature was 25℃, and the back-extraction time was 10 minutes. After back-extraction, the lithium concentration in the organic phase decreased to 0.025 g / L, and the lithium ion concentration in the back-extraction mixture was 7.2 g / L. The main components were... and excessive .

[0102] Concentration and crystallization: The back-extraction mixture is evaporated and concentrated at 80°C to a lithium concentration of about 30 g / L, cooled to 10°C to crystallize, and filtered to obtain crude lithium dihydrogen phosphate.

[0103] Refining: The crude product is recrystallized with a small amount of pure water and dried to obtain lithium dihydrogen phosphate product.

[0104] Product testing: Lithium dihydrogen phosphate content 99.8%, sulfate content 40ppm, sodium content 18ppm, calcium content 6ppm, meeting the battery-grade lithium dihydrogen phosphate standard.

[0105] Compared with related technologies, the method for preparing high-purity lithium dihydrogen phosphate provided by this invention has the following beneficial effects:

[0106] Significantly reduces sulfate impurities: Direct phosphoric acid back-extraction is used instead of traditional sulfuric acid back-extraction, avoiding the introduction of sulfate ions at the source. The back-extraction solution contains no sulfate ions. or contain only trace amounts This invention greatly simplifies subsequent impurity removal processes, significantly improves product purity, and achieves a lithium dihydrogen phosphate content of over 99.5%. It also significantly shortens the process flow: the traditional process involves "extraction-sulfuric acid back-extraction-purification-conversion (e.g., lithium carbonate conversion)-phosphoric acid neutralization-crystallization." This invention combines the back-extraction and synthesis steps into one, achieving lithium transfer and lithium dihydrogen phosphate formation in a single step. It eliminates intermediate conversion, neutralization, and multiple impurity removal steps, shortening the process flow by approximately 40%–50%, significantly reducing equipment investment and operating costs. The organic phase is recyclable: after back-extraction, the organic phase is converted into a hydrogen-type organic phase, which can be easily regenerated or directly returned to the extraction section for recycling. Extractant loss is low, and product purity is high, making it suitable for battery-grade materials: the obtained lithium dihydrogen phosphate contains less than 50 ppm sulfate and low levels of impurities such as sodium, potassium, calcium, and magnesium, allowing it to be directly used to prepare high-performance lithium iron phosphate cathode materials.

[0107] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A lithium battery waste processing device, characterized in that, include: substrate; The leaching mechanism is fixedly installed on the top of the substrate. The leaching mechanism includes a leaching tank, which is fixedly installed on the top of the substrate. A stirring motor is fixedly installed on the top of the leaching tank. A stirring shaft is fixedly installed on the output shaft of the stirring motor. The bottom end of the stirring shaft passes through the top of the leaching tank and extends into the interior. Several stirring blades are fixedly installed on the surface of the stirring shaft inside the leaching tank. A vertical groove is opened inside the stirring shaft. A water supply pipe is connected to the top of the leaching tank. A circular hole is opened on the top of the leaching tank. A crushing mechanism, which is fixedly mounted on the top of the substrate; A transfer mechanism, which is fixedly mounted on the top of the substrate; The defoaming mechanism is rotatably mounted on the surface of the stirring shaft via a bearing seat. The defoaming mechanism includes a defoaming ring and an annular plate. The defoaming ring is rotatably mounted on the surface of the stirring shaft via a bearing seat. Several defoaming plates are fixedly mounted on the circumferential side of the defoaming ring. Two fixing columns are symmetrically fixedly mounted on the top of the defoaming ring. The interior of the annular plate is slidably mounted to the interior of the vertical groove via a cylinder. Two insertion holes are symmetrically opened on the surface of the annular plate, and the two insertion holes are respectively adapted to the two fixing columns for installation. A plate and frame filter press, wherein the plate and frame filter press is fixedly installed on the top of the substrate; The two collection boxes are fixedly installed on the top of the substrate and are adapted to the outlet end of the plate and frame filter press.

2. The lithium battery waste processing device according to claim 1, characterized in that, The pulverizing mechanism includes a pulverizing chamber. Two pillars are fixedly mounted on the top of the substrate on each side of the pulverizing chamber. A first pulverizing shaft and a second pulverizing shaft are rotatably mounted inside the pulverizing chamber. One end of each shaft penetrates the inner wall of the pulverizing chamber and extends to the outside. A plurality of first pulverizing wheels and a plurality of second pulverizing wheels are fixedly mounted on the inner surfaces of the shafts, respectively, and are fitted together. A first gear and a second gear are fixedly mounted on the outer ends of the shafts, respectively, with the first gear meshing with the second gear. A pulverizing motor is fixedly mounted on one side of the pulverizing chamber via a support plate. The output shaft of the motor is fixedly connected to the outer end of the first shaft. A screen is fixedly mounted at the bottom of the pulverizing chamber, and a pulverizing funnel is fixedly mounted at the bottom of the screen. The bottom end of the funnel communicates with the top of the leaching tank.

3. The lithium battery waste processing device according to claim 1, characterized in that, The transfer mechanism includes a transfer pump, which is fixedly installed on the top of the substrate. The input end of the transfer pump is connected to the bottom of the leaching tank through a transfer pipe, and the output end of the transfer pump is connected to a riser pipe. The end of the riser pipe is connected to the input end of the plate and frame filter press.

4. The lithium battery waste processing device according to claim 1, characterized in that, A collection mechanism is fixedly installed on the top of the substrate. The collection mechanism includes a collection pump, which is fixedly installed on the top of the substrate. The input end of the collection pump is connected to a collection pipe. The two ends of the collection pipe pass through one side of the two collection boxes and extend into the interior. The output end of the collection pump is connected to a discharge pipe.

5. The lithium battery waste processing device according to claim 4, characterized in that, A cleaning mechanism is fixedly installed on the top of the substrate. The cleaning mechanism includes a cleaning tank, which is fixedly installed on the top of the substrate. The top of the cleaning tank is connected to a feed funnel, and the bottom of the cleaning tank is connected to a discharge pump through a connecting pipe. The output end of the discharge pump is connected to a discharge pipe, and the end of the discharge pipe is connected to the top of the cleaning tank.

6. The lithium battery waste processing device according to claim 5, characterized in that, A solid-liquid separator is fixedly mounted on the top of the substrate, and the end of the discharge pipe is connected to the feed end of the solid-liquid separator.

7. The lithium battery waste processing device according to claim 6, characterized in that, The outlet of the solid-liquid separator is connected to a concentration mechanism via a connecting pipe. The concentration mechanism includes a concentration pump and a concentration tank. The concentration pump is connected to the outlet of the solid-liquid separator via a connecting pipe. The output end of the concentration pump is connected to a concentration pipe. The concentration tank is fixedly installed on the top of the base plate. The end of the concentration pipe is connected to the top of the concentration tank. The bottom of the concentration tank is provided with a rotating cover via a drain pipe.

8. The lithium battery waste processing device according to claim 1, characterized in that, A sulfuric acid mechanism is fixedly installed on the top of the leaching tank. The sulfuric acid mechanism includes a sulfuric acid tank, which is fixedly installed on the top of the leaching tank. An acid addition pipe is connected to the top of the sulfuric acid tank, and an outer pipe is connected to the bottom of the sulfuric acid tank. The bottom end of the outer pipe passes through the circular hole and extends into the interior of the leaching tank. An inner pipe is slidably installed inside the outer pipe. Two floats are fixedly installed on the outer wall of the inner pipe via float plates. Two abutments are symmetrically fixedly installed on the outer wall of the inner pipe. Two sliding grooves are symmetrically opened on the surface of the outer pipe. The two abutments are slidably connected to the two sliding grooves. A switch plate is fixedly installed on the surface of the outer pipe. A switch is fixedly installed at the bottom of the switch plate and is adapted to the abutments. An opening and closing plate is rotatably installed on the bottom of the inner wall of the sulfuric acid tank via a rotating base and is adapted to the outer pipe.

9. A lithium battery waste processing device according to claim 1, characterized in that, A cylinder is fixedly installed on the top of the inner wall of the leaching tank. A bearing plate is fixedly installed on the output end of the cylinder. Two bearing columns are fixedly installed on the top of the bearing plate. An annular groove is opened on the top of the annular plate. The two bearing columns are installed in accordance with the annular groove.

10. A method for preparing high-purity lithium dihydrogen phosphate, characterized in that, The steps include the following: S1: Extraction: The waste lithium battery is transferred to a lithium battery waste processing device as described in any one of claims 1-9 for recycling to obtain lithium-rich liquid as an aqueous raw material. The lithium-rich liquid is extracted with an organic phase containing an extractant and a diluent to obtain a lithium-loaded organic phase. S2: Phosphoric acid back-extraction: Using phosphoric acid solution as a back-extraction agent, the lithium-loaded organic phase obtained in S1 is back-extracted to obtain a back-extraction mixture containing lithium dihydrogen phosphate and phosphoric acid, and a regenerated organic phase is obtained. S3: Concentration and crystallization: The back-extraction mixture obtained in S2 is evaporated and concentrated, cooled and crystallized, and the solid and liquid are separated to obtain crude lithium dihydrogen phosphate. S4: Refining: The crude lithium dihydrogen phosphate is recrystallized or washed and dried to obtain a high-purity lithium dihydrogen phosphate product.

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