An apparatus for recovering battery-grade lithium hydroxide from lithium-ion battery cathode materials.

Abstract

This invention discloses an apparatus for recovering battery-grade lithium hydroxide from lithium-ion battery cathode materials. The apparatus includes a slurry preparation system, an acidification system, a precursor preparation system, a cryogenic coarse crystallization system, and a crystallization purification system. The output of the slurry preparation system is connected to the input of the acidification system, the output of the acidification system is connected to the input of the precursor preparation system, the output of the precursor preparation system is connected to the input of the cryogenic coarse crystallization system, and the output of the cryogenic coarse crystallization system is connected to the input of the crystallization purification system. This invention removes impurities from the lithium-ion battery cathode material through the slurry preparation system, minimizing impurities. By using multiple sets of equipment in a coordinated, continuous batch processing manner, and considering the characteristics of the equipment and the material, the maximum precipitation and purification of lithium metal is achieved.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery material technology, specifically to a device for recovering battery-grade lithium hydroxide from lithium battery cathode materials. Background Technology

[0002] Currently, domestic production of lithium hydroxide mainly uses spodumene, lepidolite, brine from salt lakes, and recycled lithium black powder (such as waste lithium battery cathode materials) as raw materials. The drawbacks of the lithium ore process are high energy consumption and difficult waste disposal, while the black powder recycling process requires deep purification of impurities and presents significant wastewater treatment challenges. Therefore, recovering lithium hydroxide from lithium battery cathode materials has become an option.

[0003] Currently, the industry mainly uses acid leaching to recover lithium hydroxide from lithium battery cathode materials, but this method still has the following technical drawbacks: 1. After the lithium battery cathode material is acidified, the solution containing metal is treated to prepare a precursor. The lithium metal in the solution does not participate in the reaction and enters the freeze crystallization system with the mother liquor. Due to the excessive impurities it carries, it cannot be completely separated, resulting in poor purity of the produced lithium hydroxide. It needs to be purified twice, which is costly. 2. The lithium battery cathode material contains a lot of additives. One of the elements enters the mother liquor system after the acidification process, which reduces the speed of the production line filtration device, increases the need for additional cleaning processes, and affects the normal production rhythm of the production line. 3. When the lithium-containing solution enters the freeze crystallization system, it produces sodium sulfate, which contains a certain amount of lithium. After passing through the evaporation system, it inevitably enters the sodium sulfate. Since sodium sulfate is often sold at a low price, lithium metal is lost as it is mixed in with the sodium sulfate. Utility Model Content

[0004] The technical problem to be solved by this invention is to overcome the shortcomings of the existing technology and provide a device for recovering battery-grade lithium hydroxide from lithium battery cathode materials.

[0005] To solve the above-mentioned technical problems, the technical solution proposed by this utility model is as follows: An apparatus for recovering battery-grade lithium hydroxide from lithium-ion battery cathode materials includes a slurry preparation system, an acidification system, a precursor preparation system, a cryogenic coarse crystallization system, and a crystallization purification system. The output of the slurry preparation system is connected to the input of the acidification system, the output of the acidification system is connected to the input of the precursor preparation system, the output of the precursor preparation system is connected to the input of the cryogenic coarse crystallization system, and the output of the cryogenic coarse crystallization system is connected to the input of the crystallization purification system.

[0006] Furthermore, the impurity removal and pulping system includes a feeding station, a negative pressure device, a temporary storage silo, a conveying screw, a first washing tank, a first impurity removal conveying pump, an impurity removal filtration system, a pulping tank, a second impurity removal conveying pump, and a second washing tank, all connected in sequence.

[0007] Furthermore, the acidification system includes an acidification storage tank, a first acidification transfer pump, an acidification filtration system, a transfer storage tank, an acidification fine filtration system, a fine filtration solution storage tank, and a second acidification transfer pump, which are connected in sequence.

[0008] Furthermore, it also includes a metal solution concentration system, the input of which is connected to the output of the acidification system 2, and the output is connected to the input of the precursor preparation system.

[0009] Furthermore, the metal solution concentration system includes a metal solution storage tank, a feed pump, a first preheating device, a first falling film evaporator, a concentrate storage tank, a first metal solution transfer pump, a solution temporary storage tank, a pH adjustment storage tank, a second metal solution transfer pump, and a metal solution filtration system connected in sequence.

[0010] Furthermore, the precursor preparation system includes a precursor solution storage tank, a precursor solution metering pump, a reaction vessel, an overflow tank, a precursor filtration system, a mother liquor storage tank, a precursor fine filtration system, a Li-containing mother liquor storage tank, and a Li-containing mother liquor transfer pump, which are connected in sequence.

[0011] Furthermore, it also includes a lithium-containing solution concentration system, the input of which is connected to the output of the precursor preparation system, and the output of which is connected to the input of the cryogenic coarse crystallization system.

[0012] Furthermore, the lithium-containing solution concentration system includes, in sequence, a temporary storage tank, a heat exchanger, an ammonia removal system, a weight removal system, a solution storage tank, a lithium-containing solution transfer pump, a second preheating device, a second falling film evaporator, a falling film transfer pump, a lithium concentrate storage tank, and a lithium concentrate transfer pump.

[0013] Furthermore, the cryogenic crude crystallization system includes, in sequence, a mixing tank, a cryogenic crude crystallization transfer pump, a primary cryogenic crystallizer, a primary centrifuge, a primary mother liquor storage tank, a primary mother liquor transfer pump, a secondary cryogenic crystallizer, a centrifuge pump, a secondary centrifuge, a secondary mother liquor storage tank, a first precision filter, a cryogenic crude crystallization heat exchange system, a first evaporation heater, a first crystallization separator, a crude product solution storage tank, a crude product solution transfer pump, a crude product centrifuge, a crude product mother liquor tank, and a crude product mother liquor transfer pump.

[0014] Furthermore, the crystallization purification system includes, in sequence, a remelting storage tank, a remelting transfer pump, a second precision filter, a crystallization purification heat exchange system, a second evaporation heater, a second crystallization separator, a refined product storage tank, a refined product transfer pump, a refined product centrifuge, a drying system, a sieving system, a cooling system, a horizontal mixer, and a packaging system.

[0015] Compared with the prior art, the advantages of this utility model are: This invention removes impurities from lithium-ion battery cathode materials using a slurry preparation system, minimizing impurities. The cathode material is then acidified using an acidification system, followed by precursor preparation using a precursor preparation system. Finally, battery-grade lithium hydroxide is obtained through a freeze-crystallization and crystallization purification system, achieving the effect of lithium metal precipitation, recovery, and purification. By utilizing multiple sets of equipment in continuous batch processing, and combining the characteristics of the equipment with the material properties, the maximum precipitation and purification of lithium metal is achieved.

[0016] Furthermore, this invention employs a cyclic concentration process for the acidified metal solution to avoid the impact of unstable index control during precursor production. Taking advantage of the fact that lithium metal does not participate in the reaction during precursor production, this process separates lithium metal from nickel, cobalt, and manganese metals, yielding a lithium metal solution containing sodium sulfate. The cyclic concentration process prevents lithium metal loss. Addressing the different temperature precipitation characteristics of sodium sulfate and lithium hydroxide at low temperatures, a two-stage refrigeration system is used to precipitate sodium sulfate, resulting in a relatively pure lithium hydroxide solution. A dual-set evaporation and crystallization device is used to evaporate, crystallize, redissolve, purify, and recrystallize lithium hydroxide, improving its quality. Simultaneously, a drying and batch mixing system is incorporated to achieve the goal of producing battery-grade lithium hydroxide. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the apparatus for recovering battery-grade lithium hydroxide from lithium battery cathode materials according to a preferred embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of the impurity removal and pulping system disclosed in a preferred embodiment of the present invention; Figure 3 This is a schematic diagram of the acidification system disclosed in a preferred embodiment of the present invention; Figure 4 This is a schematic diagram of the metal solution concentration system disclosed in a preferred embodiment of the present invention; Figure 5 This is a schematic diagram of the precursor preparation system disclosed in a preferred embodiment of the present invention; Figure 6 This is a schematic diagram of the lithium-containing solution concentration system disclosed in a preferred embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of the cryogenic crude crystallization system disclosed in a preferred embodiment of the present invention; Figure 8 This is a schematic diagram of the crystallization and purification system disclosed in a preferred embodiment of the present invention.

[0018] Legend: 1. Impurity removal and pulping system; 11. Electric hoist; 12. Feeding station; 13. Negative pressure device; 14. Temporary storage silo; 15. Conveying screw; 16. First washing tank; 17. Metering facility; 18. First impurity removal conveying pump; 19. Impurity removal and filtration system; 110. Pulping tank; 111. Second impurity removal conveying pump; 112. Filtrate storage tank; 113. Second washing tank; 2. Acidification system; 21. Acidification storage tank; 22. First acidification transfer pump; 23. Acidification filtration system; 24. Transfer storage tank; 25. Acidification fine filtration system; 26. Fine filtration solution storage tank; 27. Second acidification transfer pump; 28. Dilute acid tank; 29. ​​Dilute acid metering pump; 3. Metal solution concentration system; 31. Metal solution storage tank; 32. Feed pump; 33. First preheating equipment; 34. First falling film evaporator; 35. First gas-liquid separator; 36. First steam compressor; 37. First distilled water tank; 38. First circulating water pump; 39. Concentrate storage tank; 310. First metal solution transfer pump; 311. Solution temporary storage tank; 312. pH adjustment tank; 313. Second metal solution transfer pump; 314. Metal solution filtration system; 315. First ammonia storage tank; 316. First ammonia metering pump; 4. Precursor preparation system; 41. Precursor solution storage tank; 42. Precursor solution metering pump; 43. Reaction vessel; 44. Overflow tank; 45. Precursor filtration system; 46. Mother liquor storage tank; 47. Precursor fine filtration system; 48. Li-containing mother liquor storage tank; 49. Li-containing mother liquor transfer pump; 410. Second ammonia water storage tank; 411. Alkali solution storage tank; 412. Second ammonia water metering pump; 413. Alkali solution metering pump; 5. Lithium-containing solution concentration system; 51. Temporary storage tank; 52. Heat exchanger; 53. Ammonia removal system; 54. Gravity removal system; 541. Rapid coagulation tank; 542. Precision filter; 543. Slurry tank; 544. Plate and frame filter press; 55. Solution storage tank; 56. Lithium-containing solution transfer pump; 57. Second preheating equipment; 58. Second falling film evaporator; 59. Second gas-liquid separator; 510. Second steam compressor; 511. Second distilled water tank; 512. Second circulating water pump; 513. Falling film transfer pump; 514. Lithium concentrate storage tank; 515. Lithium concentrate transfer pump; 6. Cryogenic Crystallization System; 61. Mixing Tank; 62. Cryogenic Crystallization Transfer Pump; 63. Primary Cryogenic Crystallizer; 64. Primary Centrifuge; 65. Primary Mother Liquor Storage Tank; 66. Primary Mother Liquor Transfer Pump; 67. Secondary Cryogenic Crystallizer; 68. Centrifugal Pump; 69. Secondary Centrifuge; 610. Secondary Mother Liquor Storage Tank; 611. First Precision Filter; 612. Cryogenic Crystallization Heat Exchange System; 613. First Evaporation Heater; 614. First Crystallization Separator; 615. Crude Product Solution Storage Tank; 618. Third Gas-Liquid Separator; 619. First Condensate Storage Tank; 620. First Steam Scrubber; 621. Cryogenic Crystallization Compressor; 622. Crude Product Solution Transfer Pump; 623. Crude Product Centrifuge; 624. Crude Product Mother Liquor Tank; 625. Crude Product Mother Liquor Transfer Pump; 7. Crystallization and purification system; 71. Redissolving storage tank; 72. Redissolving transfer pump; 73. Second precision filter; 74. Crystallization and purification heat exchange system; 75. Second evaporator heater; 76. Second crystallizer separator; 77. Fine product storage tank; 78. Fine product transfer pump; 79. Fine product centrifuge; 710. Drying system; 711. Sieving system; 712. Cooling system; 713. Horizontal mixer; 714. Packaging system; 715. Fourth gas-liquid separator; 716. Second condensate storage tank; 717. Second steam scrubber; 718. Crystallization and purification compressor. Detailed Implementation

[0019] To facilitate understanding of this utility model, the following description will be provided in more comprehensive and detailed manner with reference to the accompanying drawings and preferred embodiments. However, the scope of protection of this utility model is not limited to the following specific embodiments.

[0020] like Figure 1 As shown, this embodiment discloses an apparatus for recovering battery-grade lithium hydroxide from lithium-ion battery cathode materials. The raw material composition is as follows: cathode material: 58-60%; lithium metal 6.5-7.8%; elements such as Si, Na, and S ≥0.15%; K impurities ≥0.5%; moisture 0.1-0.3%. The apparatus includes a slurry preparation system 1, an acidification system 2, a metal solution concentration system 3, a precursor preparation system 4, a lithium-containing solution concentration system 5, a cryogenic coarse crystallization system 6, and a crystallization purification system 7. The output of the slurry preparation system 1 is connected to the input of the acidification system 2. The output of the acidification system 2 is connected to the input of the metal solution concentration system 3. The output of the metal solution concentration system 3 is connected to the input of the precursor preparation system 4. The output of the precursor preparation system 4 is connected to the input of the lithium-containing solution concentration system 5. The output of the lithium-containing solution concentration system 5 is connected to the input of the cryogenic coarse crystallization system 6. The output of the cryogenic coarse crystallization system 6 is connected to the input of the crystallization purification system 7.

[0021] In this embodiment, as Figure 2As shown, the impurity removal and pulping system 1 includes an electric hoist 11, a feeding station 12, a negative pressure device 13, a temporary storage silo 14, a conveying screw 15, a first washing tank 16, a first impurity removal conveying pump 18, an impurity removal filtration system 19, a pulping tank 110, a second impurity removal conveying pump 111, and a second washing tank 113 connected in sequence. In this application, the output end of the previous device is connected to the input end of the next device. In order to improve the efficiency and quality of the impurity removal and pulping system 1, it also includes a filtrate storage tank 112 and a metering device 17. The metering device 17 is connected to the first washing tank 16, the input end of the filtrate storage tank 112 is connected to the output end of the impurity removal filtration system 19, and the metering device 17 is connected to the first washing tank 16. The function of the impurity removal and pulping system 1 is to feed powdered cathode material to obtain a cathode material slurry with a stable solid content. Impurities adhering to the surface of the cathode material are removed by stirring in the first washing tank 16. After pressing through the filtration system, the impurities are discharged into the wastewater treatment system along with the wash water. The cathode material filter cake, after impurity removal, is then fed into the first washing tank 16 for pulping. To obtain cathode material with low impurity levels, the stirring speed of the stirring device needs to be controlled at 90-110 rpm / min, and the stirring time ≥3 hours.

[0022] In this embodiment, as Figure 3 As shown, the acidification system 2 includes, in sequence, an acidification storage tank 21, a first acidification transfer pump 22, an acidification filtration system 23, a transfer storage tank 24, an acidification fine filtration system 25, a fine filtration solution storage tank 26, and a second acidification transfer pump 27. To improve the efficiency and quality of the acidification system 2, it also includes a dilute acid tank 28 and a dilute acid metering pump 29. The input end of the dilute acid metering pump 29 is connected to the dilute acid tank 28, and the output end is connected to the acidification storage tank 21. The function of the acidification system 2 is to acidify the cathode material after washing and removing impurities, obtaining a solution containing nickel, cobalt, manganese, and lithium metals. This solution is then filtered through a two-stage filtration system to obtain a clear metal solution. To control the acidification process smoothly and obtain a solution with a high metal content, the acidification temperature is controlled at 50-70℃, the acid concentration at 17-20%, and the reaction time at 3-4 hours.

[0023] In this embodiment, as Figure 4As shown, the metal solution concentration system 3 includes a metal solution storage tank 31, a feed pump 32, a first preheating device 33, a first falling film evaporator 34, a concentrate storage tank 39, a first metal solution transfer pump 310, a solution temporary storage tank 311, a pH adjustment storage tank 312, a second metal solution transfer pump 313, and a metal solution filtration system 314 connected in sequence. To improve the efficiency and quality of the metal solution concentration system 3, and to reuse energy and reduce energy loss, it also includes a first gas-liquid separator 35, a first steam compressor 36, a first distilled water tank 37, and a first circulating water pump 38. The system includes a first ammonia storage tank 315 and a first ammonia metering pump 316. The output end of the first falling film evaporator 34 is connected to the input end of the first gas-liquid separator 35. The output end of the first gas-liquid separator 35 is connected to the input ends of the first steam compressor 36 and the first distilled water tank 37. The input end of the first steam compressor 36 is connected to the first falling film evaporator 34. The input end of the first circulating water pump 38 is connected to the input end of the first distilled water tank 37, and the output end is connected to the first preheating device 33. The first ammonia storage tank 315 is connected to the pH adjustment storage tank 312 through the first ammonia metering pump 316. The function of the metal solution concentration system 3 is to further concentrate the metal solution obtained in the previous step to achieve the maximum concentration, with the nickel / cobalt / manganese metal concentration reaching 100-115 g / L and the lithium concentration reaching 24-30 g / L. The purpose is to achieve the best precipitation effect in subsequent processes. The concentration process here adopts falling film concentration, and the target concentration is achieved by controlling the specific gravity of the solution and the evaporation temperature. Then, the pH of the solution is adjusted back to 5-6, and the solution is filtered through the filtration system.

[0024] In this embodiment, as Figure 5 As shown, the precursor preparation system 4 includes a precursor solution storage tank 41, a precursor solution metering pump 42, a reaction vessel 43, an overflow storage tank 44, a precursor filtration system 45, a mother liquor storage tank 46, a precursor fine filtration system 47, a Li-containing mother liquor storage tank 48, and a Li-containing mother liquor transfer pump 49 connected in sequence. In order to improve the efficiency and quality of the precursor preparation system 4, it also includes a second ammonia water storage tank 410, an alkali solution storage tank 411, a second ammonia water metering pump 412, and an alkali solution metering pump 413. The input end of the second ammonia water metering pump 412 is connected to the second ammonia water storage tank 410, and the output end is connected to the reaction vessel 43. The input end of the alkali solution metering pump 413 is connected to the alkali solution storage tank 411, and the output end is connected to the reaction vessel 43. The function of precursor preparation system 4 is to add concentrated metal solution, ammonia, and liquid alkali into the reaction vessel in a certain proportion. By controlling the reaction temperature at 60±5℃ and the pH at 11±1, the purpose is to precipitate the metallic nickel / cobalt / manganese in the solution in a very high proportion, and obtain a clear lithium-containing solution through the filtration system.

[0025] In this embodiment, as Figure 6As shown, the lithium-containing solution concentration system 5 includes a temporary storage tank 51, a heat exchanger 52, an ammonia removal system 53, a weight removal system 54, a solution storage tank 55, a lithium-containing solution transfer pump 56, a second preheating device 57, a second falling film evaporator 58, a falling film transfer pump 513, a lithium concentrate storage tank 514, and a lithium concentrate transfer pump 515, connected in sequence. To improve the efficiency and quality of the lithium-containing solution concentration system 5, and to reuse energy and reduce energy loss, it also includes a second gas-liquid separator 59 and a second steam compressor 510. The second distilled water tank 511 and the second circulating water pump 512 are connected. The input end of the second gas-liquid separator 59 is connected to the second falling film evaporator 58, and the output end is connected to the input end of the second steam compressor 510 and the second distilled water tank 511. The input end of the second circulating water pump 512 is connected to the output end of the second distilled water tank 511, and the output end is connected to the second preheating device 57. The input end of the second steam compressor 510 is connected to the output end of the second gas-liquid separator 59, and the output end is connected to the second falling film evaporator 58. The function of the lithium-containing solution concentration system 5 is to further concentrate the clarified lithium-containing solution after it has passed through the ammonia removal system and the gravimetric removal system, so that the lithium metal concentration reaches above 18 g / L and the sodium sulfate concentration is increased to above 20%. The purpose is to improve the purification efficiency of subsequent processes. The concentration equipment used in the system is a falling film evaporator.

[0026] In this embodiment, as Figure 7As shown, the cryogenic crude crystallization system 6 includes, in sequence, a mixing tank 61, a cryogenic crude crystallization transfer pump 62, a primary cryogenic crystallizer 63, a primary centrifuge 64, a primary mother liquor storage tank 65, a primary mother liquor transfer pump 66, a secondary cryogenic crystallizer 67, a centrifuge pump 68, a secondary centrifuge 69, a secondary mother liquor storage tank 610, a first precision filter 611, a cryogenic crude crystallization heat exchange system 612, a first evaporation heater 613, a first crystallization separator 614, a crude product solution storage tank 615, a crude product solution transfer pump 622, a crude product centrifuge 623, a crude product mother liquor tank 624, and a crude product mother liquor transfer pump 625. This system is designed to improve the cryogenic crude crystallization efficiency. To improve the efficiency and quality of the crystallization system 6 and to reuse energy and reduce energy loss, it also includes a third gas-liquid separator 618, a first condensate storage tank 619, a first steam scrubbing tower 620, and a refrigerated crude crystallizer compressor 621. The input end of the third gas-liquid separator 618 is connected to the first crystallizer separator 614, and its output end is connected to the input ends of the first steam scrubbing tower 620 and the first condensate storage tank 619. The input end of the refrigerated crude crystallizer compressor 621 is connected to the output end of the first steam scrubbing tower 620, and its output end is connected to the first evaporator heater 613. The output end of the first condensate storage tank 619 is connected to the refrigerated crude crystallization heat exchange system 612. The input end of the crude product centrifuge 623 is connected to the input end of the crude product solution transfer pump 622, and its output end is connected to the first crystallizer separator 614. The function of the cryogenic crude crystallization system 6 is to add liquid alkali to the concentrated lithium metal solution for causticization, converting it into LiOH. Then, taking advantage of the different low-temperature precipitation temperatures of LiOH and sodium sulfate, the solution is passed through a two-stage refrigeration system to obtain a lithium hydroxide solution with a low impurity concentration. Subsequently, it enters the crude product evaporation crystallization system for further purification to obtain a crude lithium hydroxide solution.

[0027] In this embodiment, as Figure 8As shown, the crystallization purification system 7 includes, in sequence, a redissolving storage tank 71, a redissolving transfer pump 72, a second precision filter 73, a crystallization purification heat exchange system 74, a second evaporation heater 75, a second crystallization separator 76, a refined product storage tank 77, a refined product transfer pump 78, a refined product centrifuge 79, a drying system 710, a sieving system 711, a cooling system 712, a horizontal mixer 713, and a packaging system 714. To improve the efficiency and quality of the crystallization purification system 7, and to reuse energy and reduce energy loss, it also includes a fourth gas-liquid separator 715 and a second condensate storage tank 71. 6. The input end of the second steam scrubbing tower 717 and the crystallization purification compressor 718, and the fourth gas-liquid separator 715 are connected to the second crystallization separator 76, and the output end is connected to the second condensate storage tank 716 and the input end of the second steam scrubbing tower 717. The input end of the crystallization purification compressor 718 is connected to the output end of the second steam scrubbing tower 717, and the output end is connected to the second evaporation heater 75. The output end of the crystallization purification heat exchange system 74 and the fourth gas-liquid separator 715 is connected to the input end of the second condensate storage tank 716, and the output end of the second condensate storage tank 716 is connected to the resolution storage tank 71. The function of the crystallization purification system 7 is to centrifuge the crude lithium hydroxide solution, redissolve it, and then purify and crystallize it through a fine filtration system and a fine evaporation crystallizer. After passing through a drying system and a sieving system, high-quality lithium hydroxide with lower impurities is obtained. The characteristic of this system is that the redissolved purification and crystallization process ensures that the impurity quality of the lithium hydroxide is at a low level, which meets the battery-grade lithium hydroxide standard.

[0028] It should be noted that this invention is used for the separation of lithium metal in lithium battery cathode materials. Simultaneously, it can resynthesize nickel, cobalt, and manganese metals from lithium battery cathode materials into precursors for cathode material production through proportional adjustment, avoiding metal loss and the wastewater treatment pressure associated with extraction methods. Furthermore, the lithium-containing metal solution is prepared into battery-grade lithium hydroxide (monohydrate or anhydrous) through a multi-stage process, allowing the lithium metal to be converted back into a product for external sale or internal use. The lithium-containing solution is combined with two sets of circulating concentration systems through concentration determination, ensuring continuous metal circulation within the system without loss. Further, the device can also use the impurity removal and slurry preparation system 1, acidification system 2, metal solution concentration system 3, and precursor preparation system 4 as purification and reuse devices for waste or substandard precursors, realizing the recycling of precursor waste during the production process.

[0029] The implementation steps of this utility model are as follows: Step 1: Use electric hoist 11 to drop the material into feeding station 12. After being transported to temporary storage silo 14 by negative pressure device 13, pure water is first added to the first washing tank 16 through metering device 17. Then, the material is added to the first washing tank 16 through conveying screw 15. After being stirred and washed for a certain period of time, it is pumped into the impurity removal filtration system 19 through the first impurity removal pump 18 for filtration. The filtrate enters the filtrate storage tank 112 and is then pumped into the sewage treatment system for treatment. Pure water is added to pulping storage tank 110 through metering device 17. Then, the material after pressing by the filtration system is transferred to pulping storage tank 110 for stirring. After the material is completely stirred, it is transported to acidification system 2 through second impurity removal pump 111.

[0030] Step 2: First, dilute acid in dilute acid tank 28 is added to acidification storage tank 21 through metering pump 29. Then, the slurry prepared in step 1 is transferred to acidification storage tank 21. By controlling the reaction temperature, time, pH and other conditions, the reaction is completed (LiMO2+H2SO4→Li2SO4+MSO4+H2O, M=metal). The first acidification transfer pump 22 is used to pump the solution into acidification filtration system 23. After separating the filtrate from the filter residue, it is transferred to transfer storage tank 24 and then into acidification fine filtration system 25 for fine filtration. The solution is output to fine filtration solution storage tank 26. The second acidification transfer pump 27 is used to transport the metal solution to metal solution concentration system 3.

[0031] Step 3: Transfer the metal solution from Step 2 to the metal solution storage tank 31. Use the feed pump 32 to pump the solution into the first preheating device 33 (feed plate heat exchanger and non-condensable vapor heat exchanger) for preheating. Then, it enters the first falling film evaporator 34 for concentration. The concentrated solution enters the concentrate storage tank 39. The vapor and liquid produced during concentration are separated by a separator. The vapor passes through the first steam compressor 36 and is used again as a heat source to heat the first falling film evaporator 34. The liquid enters the first distilled water tank 37 and is pumped into the first preheating device 33 by the first circulating water pump 38. The metal solution is preheated to achieve heat energy recycling and reduce energy consumption. Distilled water is output to the utility after heat exchange in the first preheating device 33. The solution in the concentrate storage tank 39 is then transferred to the pH adjustment storage tank 312. Ammonia water in the first ammonia water storage tank 315 is pumped into the pH adjustment storage tank 312 through the first ammonia water metering pump 316 to adjust the pH and remove impurity ions from the solution. The qualified solution enters the metal solution filtration system 314 through the second metal solution transfer pump 313. After filtration, it enters the precursor preparation system 4.

[0032] Step 4: Transfer the concentrated metal solution filtered in Step 3 to the precursor solution storage tank 41, and then pump it into the reaction vessel 43 via the precursor solution metering pump 42. Simultaneously, ammonia and alkali solutions from the second ammonia storage tank 410 and the alkali storage tank 411 are added to the reaction vessel 43 in parallel flow via the second ammonia metering pump 412 and the alkali metering pump 413, respectively. During this operation, the metal solution, ammonia, and alkali solution are continuously added to the reaction vessel 43 in parallel flow at a certain ratio. The reaction is carried out continuously by controlling the reaction temperature, pH, and other conditions (M). 2+ +2OH - =M(OH)2, M=metal), the produced material enters the overflow storage tank 44 and is then transported to the precursor filtration system 45 (mainly a plate and frame filter press) to separate the material from the mother liquor. At this time, the mother liquor basically contains only metallic lithium, and the remaining metallic nickel, cobalt, manganese, etc. <20ppm. After the mother liquor enters the mother liquor storage tank 46, it then enters the precursor fine filtration system 47. The filtered clarified lithium-containing solution enters the Li-containing mother liquor storage tank 48 and is finally transferred to the lithium-containing solution concentration system 5 by the Li-containing mother liquor transfer pump 49.

[0033] Step 5: The clarified lithium-containing solution produced in Step 4 is transferred to a temporary storage tank 51. After passing through a heat exchanger 52, it enters the deammoniation system 53 (the main equipment is a stripping deammoniation tower). The purpose is to remove excess unreacted ammonia from the precursor preparation system 4. The deammoniation-reduced lithium-containing solution then enters the gravimetric removal system 54 (the main equipment includes a rapid coagulation tank 541, a precision filter 542, a slurry tank 543, and a plate and frame filter press 544 connected in sequence. The input end of the rapid coagulation tank 541 is connected to the output end of the deammoniation system 53, and the output end of the precision filter 542 is connected to the input end of the solution storage tank 55. These are all conventional devices, and the filter residue is output from the plate and frame filter press 544). After passing through the deammoniation and gravimetric removal systems, the lithium-containing solution enters the solution storage tank 55 and is then transported by lithium-containing solution conveying system. Pump 56 pumps the solution into the second preheating device 57 (plate heat exchanger) for preheating, and then into the second falling film evaporator 58 to concentrate it to a certain concentration. The concentrated solution is transferred to the lithium concentrate storage tank 514 by the falling film transfer pump 513. The vapor and liquid generated by concentration are separated by the second gas-liquid separator 59. The vapor is compressed by the second steam compressor 510 and then used as a heat source to heat the second falling film evaporator 58. The liquid enters the second distilled water tank 511 and is pumped into the second preheating device 57 by the second circulating water pump 512 to preheat the lithium-containing solution. The distilled water is output to the utility after heat exchange in the second preheating device 57. The concentrated solution in the lithium concentrate storage tank 514 is transferred to the cryogenic coarse crystallization system 6 by the lithium concentrate transfer pump 515.

[0034] Step Six: The lithium concentrate solution from Step Five is pumped into the mixing tank 61 via pump 515. Liquid alkali from the liquid alkali storage tank is added to the mixing tank 61 using a metering pump to causticize the lithium concentrate solution. + +OH - =LiOH), the causticized solution enters the primary cryogenic crystallizer 63 via the cryogenic coarse crystallization transfer pump 62, with a temperature requirement of <10℃, to remove most of the sodium sulfate from the solution beforehand. The solution then enters the primary centrifuge 64 for centrifugation. The centrifuged solution enters the primary mother liquor storage tank 65 and is then transferred to the secondary cryogenic crystallizer 67 via the primary mother liquor transfer pump 66, with a temperature requirement of ≤0℃. During this process, more than 98% of the remaining sodium sulfate needs to be removed from the solution. The solution in the secondary cryogenic crystallizer 67 is then centrifuged in the secondary centrifuge 69 via the centrifuge pump 68. The solution is then transferred to the secondary mother liquor storage tank 610 and then enters the first precision filter 611 to intercept impurities. The filtered solution enters the cryogenic coarse crystallization heat exchange system 612 (the main equipment is a plate heat exchanger). When this system is first started, it requires external steam heating as the heat source. After the equipment stabilizes, the internal heat source exchanges heat with the cryogenic coarse crystallization heat exchange system 612. The solution after passing through the heat exchange system enters the first evaporator heater 613, where the evaporator temperature needs to be maintained at a high level before being transferred to the secondary cryogenic crystallizer 614. After the first crystallizer 614, ensuring that the solid content and Li content of the produced solution meet the process requirements, the solution produced by the first crystallizer 614 enters the crude solution storage tank 615. The separated gas and a portion of the condensed liquid enter the third gas-liquid separator 618 for separation. The produced gas is purified by the first steam scrubbing tower 620 and then enters the refrigerated crude crystallizer compressor 621 for compression, before returning to the first evaporator heater 613 as a heat source for heating. The compressed hot steam is circulated and heated in the first evaporator heater 613 before being used as secondary steam. The liquid enters the cryogenic coarse crystallization heat exchange system 612 as a heat source for preheating. After preheating, the condensed liquid enters the first condensate storage tank 619 and is output to the utility system along with the liquid separated by the third gas-liquid separator 618. The solution in the crude product solution storage tank 615 is centrifuged in the crude product centrifuge 623 via the crude product solution transfer pump 622. The mother liquor after centrifugation enters the crude product mother liquor tank 624 and is then re-entered into the first crystallization separator 614 for separation via the crude product mother liquor transfer pump 625. The centrifuged material enters the crystallization purification system 7.

[0035] Step 7: Transfer the centrifuged material from Step 6 to the resolution storage tank 71 for dissolution. The solvent used for dissolution is transferred from the second condensate storage tank 716. The dissolution time is ≥1 hour. The solution in the resolution storage tank 71 is then transported to the second precision filter 73 by the resolution transfer pump 72, and then enters the crystallization purification heat exchange system 74 for preheating. After preheating, it enters the second evaporation heater 75 for evaporation. After evaporation, the solution enters the second crystallization separator 76 for separation, ensuring that the solid content and Li content of the produced solution meet the process requirements. The solution produced by the second crystallization separator 76 enters the refined product storage tank 77. The gas separated in the second crystallization separator 76 and a portion of the condensed liquid enter the fourth gas-liquid separator 715 for separation. The generated gas is purified by the second steam scrubbing tower 717 and then enters the crystallization purification compressor 718 for compression. After compression, it is returned to the second evaporation heater 75 as a heat source for further heating. The solution, after passing through the second evaporator heater 75, continues to enter the crystallization purification heat exchange system 74 in the form of secondary steam to preheat the solution, and then returns to the second condensate storage tank 716. The condensate in the storage tank enters the resolution storage tank 71 as a solvent to continue dissolving the centrifuged material finally produced in step six. The solution in the refinement storage tank 77 is transported to the refinement centrifuge 79 by the refinement transfer pump 78 for centrifugation. The mother liquor after centrifugation enters the refinement mother liquor tank 719 and is returned to the second crystallizer separator 76 by a pump for further separation and crystallization. The material in the centrifuge is conveyed by a screw conveyor into the drying system 710 for drying. After drying, the material enters the sieving system 711 (the main equipment is a vibrating screen) for sieving. After sieving, it is transferred to the cooling system 712 for cooling. After the material is cooled, it enters the horizontal mixer 713 for batch mixing. After being fully mixed, it enters the packaging system 714 for packaging, and finally, battery-grade LiOH is produced.

[0036] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the present invention, or modify it into equivalent embodiments, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, should fall within the protection scope of the present invention.

Claims

1. An apparatus for recovering battery-grade lithium hydroxide from lithium-ion battery cathode materials, characterized in that, The system includes a pulping system (1), an acidification system (2), a precursor preparation system (4), a cryogenic crystallization system (6), and a crystallization purification system (7). The output of the pulping system (1) is connected to the input of the acidification system (2), the output of the acidification system (2) is connected to the input of the precursor preparation system (4), the output of the precursor preparation system (4) is connected to the input of the cryogenic crystallization system (6), and the output of the cryogenic crystallization system (6) is connected to the input of the crystallization purification system (7).

2. The apparatus for recovering battery-grade lithium hydroxide from lithium-ion battery cathode materials according to claim 1, characterized in that, The impurity removal and pulping system (1) includes a feeding station (12), a negative pressure device (13), a temporary storage silo (14), a conveying screw (15), a first washing tank (16), a first impurity removal conveying pump (18), an impurity removal filtration system (19), a pulping tank (110), a second impurity removal conveying pump (111), and a second washing tank (113) connected in sequence.

3. The apparatus for recovering battery-grade lithium hydroxide from lithium-ion battery cathode materials according to claim 1, characterized in that, The acidification system (2) includes an acidification storage tank (21), a first acidification transfer pump (22), an acidification filtration system (23), a transfer storage tank (24), an acidification fine filtration system (25), a fine filtration solution storage tank (26), and a second acidification transfer pump (27) connected in sequence.

4. The apparatus for recovering battery-grade lithium hydroxide from lithium-ion battery cathode materials according to claim 1, characterized in that, It also includes a metal solution concentration system (3), the input of which is connected to the output of the acidification system (2), and the output is connected to the input of the precursor preparation system (4).

5. The apparatus for recovering battery-grade lithium hydroxide from lithium-ion battery cathode materials according to claim 4, characterized in that, The metal solution concentration system (3) includes a metal solution storage tank (31), a feed pump (32), a first preheating device (33), a first falling film evaporator (34), a concentrate storage tank (39), a first metal solution transfer pump (310), a solution temporary storage tank (311), a pH adjustment storage tank (312), a second metal solution transfer pump (313), and a metal solution filtration system (314) connected in sequence.

6. The apparatus for recovering battery-grade lithium hydroxide from lithium-ion battery cathode materials according to claim 1, characterized in that, The precursor preparation system (4) includes a precursor solution storage tank (41), a precursor solution metering pump (42), a reaction vessel (43), an overflow storage tank (44), a precursor filtration system (45), a mother liquor storage tank (46), a precursor fine filtration system (47), a Li-containing mother liquor storage tank (48), and a Li-containing mother liquor transfer pump (49), which are connected in sequence.

7. The apparatus for recovering battery-grade lithium hydroxide from lithium-ion battery cathode materials according to claim 1, characterized in that, It also includes a lithium-containing solution concentration system (5), the input of which is connected to the output of the precursor preparation system (4), and the output is connected to the input of the cryogenic crystallization system (6).

8. The apparatus for recovering battery-grade lithium hydroxide from lithium-ion battery cathode materials according to claim 7, characterized in that, The lithium solution concentration system (5) includes a temporary storage tank (51), a heat exchanger (52), an ammonia removal system (53), a weight removal system (54), a solution storage tank (55), a lithium solution transfer pump (56), a second preheating device (57), a second falling film evaporator (58), a falling film transfer pump (513), a lithium concentrate storage tank (514), and a lithium concentrate transfer pump (515), which are connected in sequence.

9. The apparatus for recovering battery-grade lithium hydroxide from lithium-ion battery cathode materials according to claim 1, characterized in that, The cryogenic coarse crystallization system (6) includes, in sequence, a mixing tank (61), a cryogenic coarse crystallization transfer pump (62), a primary cryogenic crystallizer (63), a primary centrifuge (64), a primary mother liquor storage tank (65), a primary mother liquor transfer pump (66), a secondary cryogenic crystallizer (67), a centrifuge pump (68), a secondary centrifuge (69), a secondary mother liquor storage tank (610), a first precision filter (611), a cryogenic coarse crystallization heat exchange system (612), a first evaporation heater (613), a first crystallization separator (614), a crude product solution storage tank (615), a crude product solution transfer pump (622), a crude product centrifuge (623), a crude product mother liquor tank (624), and a crude product mother liquor transfer pump (625).

10. The apparatus for recovering battery-grade lithium hydroxide from lithium-ion battery cathode materials according to claim 1, characterized in that, The crystallization purification system (7) includes a redissolved storage tank (71), a redissolved transfer pump (72), a second precision filter (73), a crystallization purification heat exchange system (74), a second evaporation heater (75), a second crystallization separator (76), a refined product storage tank (77), a refined product transfer pump (78), a refined product centrifuge (79), a drying system (710), a sieving system (711), a cooling system (712), a horizontal mixer (713), and a packaging system (714), which are connected in sequence.

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