Process and equipment for recycling and preparing battery-grade lithium carbonate from spent lithium battery positive active material

Abstract

The application provides a process and equipment for recycling waste lithium battery positive active material to prepare battery-grade lithium carbonate, relates to the technical field of lithium battery raw material preparation, and comprises the following steps: step S1, uniformly mixing pretreated positive active material and polypropylene according to a certain proportion, placing in a semi-batch pyrolysis device for pyrolysis treatment to obtain pyrolysis products; step S2, water immersion and filtration of the pyrolysis products to obtain a lithium carbonate solution and residues; and step S3, concentration and crystallization of the lithium carbonate solution to obtain crude lithium carbonate. According to the scheme, the gas generated in the pyrolysis process can be recycled, waste gas emission is reduced, lithium exists in the form of carbonate, water immersion is directly performed, the use of a large amount of chemical reagents is avoided, the difficulty of wastewater treatment is reduced, lithium is recycled in the form of battery-grade lithium carbonate, lithium carbonate, as a core basic raw material of lithium battery positive materials, can be reused for the production of lithium batteries, and lithium resource recycling is achieved.

Description

Technical Field

[0001] This invention relates to the field of lithium battery raw material preparation, and in particular to the process and equipment for recycling waste lithium battery cathode active materials to prepare battery-grade lithium carbonate. Background Technology

[0002] Used lithium batteries refer to lithium-ion batteries that are no longer usable due to various problems. If not disposed of in accordance with regulations, they will release harmful substances through soil, water, and the atmosphere. The strategic resources they contain, such as lithium, cobalt, and nickel, can be recycled. Battery-grade lithium carbonate is a core raw material for lithium battery production. Recycling used lithium batteries to produce battery-grade lithium carbonate is a key path to achieving a closed-loop cycle of lithium resources and promoting the sustainable development of the new energy industry. This approach can address the environmental and safety hazards of used lithium batteries and compensate for the supply shortage of lithium ore resources.

[0003] With the widespread use of electric vehicles and portable electronic devices, the number of used lithium-ion batteries has increased dramatically, putting enormous pressure on the environment and resources. Used lithium batteries contain a large amount of valuable metals such as lithium, cobalt, and nickel, and have extremely high recycling value. At the same time, the demand for high-purity lithium carbonate in the lithium-ion battery production process is growing, while traditional purification processes suffer from problems such as high energy consumption and large emissions.

[0004] Therefore, it is necessary to provide processes and equipment for recycling waste lithium battery cathode active materials to prepare battery-grade lithium carbonate to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides a process and equipment for recycling positive electrode active materials from waste lithium batteries to prepare battery-grade lithium carbonate, which solves the problems of high energy consumption and large emissions in traditional waste lithium battery recycling processes.

[0006] To solve the above-mentioned technical problems, the process for preparing battery-grade lithium carbonate from recycled waste lithium battery cathode active materials provided by the present invention includes the following steps:

[0007] Step S1: Mix the pretreated positive electrode active material with polypropylene in a certain proportion, and place it in a semi-batch pyrolysis device for pyrolysis treatment to obtain pyrolysis products.

[0008] Step S2: The pyrolysis product is leached in water and filtered to obtain a lithium carbonate solution and residue;

[0009] Step S3: Concentrate and crystallize the lithium carbonate solution to obtain crude lithium carbonate;

[0010] Step S4: Mix crude lithium carbonate and water in a certain proportion and stir to obtain lithium carbonate slurry;

[0011] Step S5: The combustion exhaust gas is introduced into the lithium carbonate slurry and carbonization reaction is carried out in the reaction tank 1. After filtration, a pure lithium bicarbonate solution and residue 1 are obtained.

[0012] Step S6: Heat the pure lithium bicarbonate solution, dry and pulverize it to obtain battery-grade lithium carbonate;

[0013] Step S7: Grind the residue obtained in step S2 and perform magnetic separation to obtain magnetic and non-magnetic materials. The magnetic material is mainly nickel-cobalt alloy, and the non-magnetic material is mainly manganese oxide.

[0014] Step S8: Mix the non-magnetic substance and residue 1, then acid-leach, purify, and filter to obtain the filtrate;

[0015] Step S9: Adjust the pH of the filtrate, add ammonium persulfate to react, wash, dry, and calcine to obtain solid manganese dioxide.

[0016] Preferably, in step S1, the generated gas mainly includes reducing gases such as hydrogen and methane, which can be circulated in the pyrolysis device to promote the reduction of the positive electrode active material. In step S5, the combustion exhaust gas comes from a thermal power plant or industrial boiler and contains carbon dioxide gas. In step S6, carbon dioxide will be released, which can be captured by a gas collection device, purified, and reused for carbonization reaction or other industrial uses.

[0017] Equipment for recycling waste lithium battery cathode active materials to prepare battery-grade lithium carbonate, including a reaction tank, a sealing cover, a drive mechanism, and a tapping mechanism;

[0018] The drive mechanism includes a mounting frame fixed to the inner wall of the reaction tank. A rotating shaft is vertically rotatably connected inside the mounting frame. A drive gear is connected to the circumferential side of the rotating shaft and the bottom of the mounting frame via a keyway. Two rotating shafts are vertically rotatably connected inside the mounting frame and on both sides of the rotating shaft. A driven gear is fixed to the circumferential side of the two rotating shafts and the bottom of the mounting frame. The two driven gears mesh with the drive gear. A cam is fixed to the circumferential side of the two rotating shafts and inside the mounting frame.

[0019] The striking mechanism includes two connecting plates fixed inside the left side of the mounting frame. A reciprocating rod is vertically slidably connected inside the two connecting plates. A spring is sleeved on the circumferential side of the reciprocating rod and at the bottom of the bottom connecting plate. A striking frame is fixed at the bottom end of the reciprocating rod. A wire mesh is provided on the inner side of the striking frame. A connecting plate is rotatably connected to the left side of the back wall of the mounting frame. A rotating wheel is rotatably connected to the right side of the connecting plate and at the bottom of the left cam. The surface of the rotating wheel is in contact with the bottom of the left cam. The left side of the connecting plate is located inside the reciprocating rod. A snap-fit ​​component is provided inside the reciprocating rod and inside the connecting plate.

[0020] Preferably, the reciprocating rod has a through groove for the movement of the connecting plate, the left side of the connecting plate has a slot for use with the snap-fit ​​component, the tapping mechanism has two sets arranged in a mirror image, and the sealing cover is fixedly connected to the top of the reaction tank by bolts.

[0021] Preferably, an auxiliary mechanism is fixedly provided on the left side of the top of the sealing cover. The auxiliary mechanism includes a storage cylinder fixedly provided on the left side of the top of the sealing cover. The top end of the reciprocating rod passes through the bottom of the sealing cover and extends into the interior of the storage cylinder. A piston is fixedly provided on the top end of the reciprocating rod and inside the storage cylinder. An extraction tube is connected to the top of the storage cylinder. A delivery tube is connected to the left side of the storage cylinder. The bottom end of the delivery tube passes through the top of the sealing cover and extends into the interior of the reaction tank.

[0022] Preferably, a swing spraying mechanism is fixedly provided at the bottom of the front side of the mounting frame. The swing spraying mechanism includes two mounting brackets fixedly provided at the bottom of the front side of the mounting frame. Spray pipes are rotatably connected to the interior of the two mounting brackets. Multiple nozzles are connected to the surface of the spray pipes. A drive toothed plate is fixedly provided on the inner side of the beater frame. A swing gear is fixedly provided on the surface of the spray pipes. The swing gear meshes with the drive toothed plate.

[0023] Preferably, the auxiliary mechanism is arranged in two sets in a left-right mirror configuration, the oscillating spraying mechanism is arranged in two sets in the front and rear configurations, the storage cylinder is used to store deionized water or defoamer, and the delivery pipe is connected to the spraying pipe.

[0024] Preferably, a stirring mechanism is fixedly provided on the surface of the rotating shaft, the stirring mechanism includes a stirring paddle fixedly provided on the surface of the rotating shaft, a mounting base is fixedly provided on the top of the sealing cover, and a drive motor for driving the rotating shaft to rotate is provided on the top of the mounting base, the rotating shaft is rotatably connected to the sealing cover.

[0025] Preferably, the bottom of both sides of the reaction tank is connected to a feed pipe, the top of the right side of the reaction tank is connected to an exhaust pipe, the right side of the bottom of the reaction tank is connected to a discharge pipe, the bottom of the reaction tank is fixed with a support leg, and multiple air inlet pipes are arranged longitudinally inside the reaction tank, with an air outlet nozzle at the top of each of the multiple air inlet pipes.

[0026] Compared with related technologies, the process for recycling waste lithium battery cathode active materials to prepare battery-grade lithium carbonate provided by this invention has the following beneficial effects:

[0027] The gases generated during pyrolysis can be recycled, reducing waste gas emissions. Lithium exists in the form of carbonate, which can be directly leached in water, avoiding the use of large amounts of chemical reagents and reducing the difficulty of wastewater treatment. Lithium is recycled in the form of battery-grade lithium carbonate. As the core raw material for lithium battery cathode materials, lithium carbonate can be reused in the production of lithium batteries, realizing the recycling of lithium resources. It can also recover valuable metals such as nickel and cobalt through subsequent processing, improving resource utilization, avoiding the high energy consumption problem of pre-concentrated carbon dioxide in traditional processes, and improving product purity. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0029] Figure 1 The optimal structural schematic diagram provided for this invention;

[0030] Figure 2 This is a schematic diagram of the structure of the reaction tank (right view) provided by the present invention.

[0031] Figure 3 for Figure 1 The diagram shows a cross-sectional view of the reaction tank.

[0032] Figure 4 This is a schematic diagram of the drive mechanism and the striking mechanism provided by the present invention;

[0033] Figure 5 for Figure 4 The diagram shows the structure of the drive mechanism.

[0034] Figure 6 for Figure 4 The diagram shows the structure of the striking structure.

[0035] Figure 7 for Figure 6 The enlarged structural diagram at point A is shown below;

[0036] Figure 8 A schematic diagram of the auxiliary mechanism provided by the present invention;

[0037] Figure 9 for Figure 8 The diagram shows a cross-sectional view of the storage cylinder.

[0038] Figure 10 This is a schematic diagram of the oscillating spraying mechanism provided by the present invention;

[0039] Figure 11 A schematic diagram of the state provided by the present invention, in which the left-side tapping plate drives the drive tooth plate to move downward, causing the swing gear to drive the spray pipe to rotate counterclockwise.

[0040] Figure 12 This is a schematic diagram of the stirring mechanism provided by the present invention.

[0041] Explanation of icon numbers:

[0042] 1. Reaction tank; 2. Sealing cap;

[0043] 3. Drive mechanism; 31. Mounting bracket; 32. Rotating shaft; 33. Driving gear; 34. Rotating shaft; 35. Driven gear; 36. Cam;

[0044] 4. Beating mechanism; 41. Connecting plate; 42. Reciprocating rod; 43. Spring; 44. Beating frame; 45. Wire mesh; 46. Connecting plate; 47. Rotating wheel; 48. Clip-on component;

[0045] 5. Auxiliary mechanism; 51. Storage cylinder; 52. Piston; 53. Extraction tube; 54. Delivery tube;

[0046] 6. Oscillating spraying mechanism; 61. Mounting bracket; 62. Spray pipe; 63. Spray head; 64. Drive gear plate; 65. Oscillating gear;

[0047] 7. Stirring mechanism; 71. Stirring paddle; 72. Mounting base; 73. Drive motor;

[0048] 8. Feed pipe; 9. Exhaust pipe; 10. Discharge pipe; 11. Support leg; 12. Air inlet pipe; 13. Air outlet nozzle. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0050] This invention provides a process for recycling positive electrode active materials from waste lithium batteries to prepare battery-grade lithium carbonate.

[0051] The process for recycling spent lithium battery cathode active materials to prepare battery-grade lithium carbonate includes the following steps:

[0052] Step S1: Mix the pretreated positive electrode active material with polypropylene in a certain proportion, and place it in a semi-batch pyrolysis device for pyrolysis treatment to obtain pyrolysis products.

[0053] Step S2: The pyrolysis product is leached in water and filtered to obtain a lithium carbonate solution and residue;

[0054] Step S3: Concentrate and crystallize the lithium carbonate solution to obtain crude lithium carbonate;

[0055] Step S4: Mix crude lithium carbonate and water in a certain proportion and stir to obtain lithium carbonate slurry;

[0056] Step S5: The combustion exhaust gas is introduced into the lithium carbonate slurry and carbonization reaction is carried out in the reaction tank 1. After filtration, a pure lithium bicarbonate solution and residue 1 are obtained.

[0057] Step S6: Heat the pure lithium bicarbonate solution, dry and pulverize it to obtain battery-grade lithium carbonate;

[0058] Step S7: Grind the residue obtained in step S2 and perform magnetic separation to obtain magnetic and non-magnetic materials. The magnetic material is mainly nickel-cobalt alloy, and the non-magnetic material is mainly manganese oxide.

[0059] Step S8: Mix the non-magnetic substance and residue 1, then acid-leach, purify, and filter to obtain the filtrate;

[0060] Step S9: Adjust the pH of the filtrate, add ammonium persulfate to react, wash, dry, and calcine to obtain solid manganese dioxide.

[0061] In step S1, the generated gases mainly include reducing gases such as hydrogen and methane, which can be circulated in the pyrolysis device to promote the reduction of the positive electrode active material. In step S5, the combustion exhaust gas comes from a thermal power plant or industrial boiler and contains carbon dioxide gas. In step S6, carbon dioxide will be released, which can be captured by a gas collection device, purified, and reused in the carbonization reaction or other industrial applications.

[0062] Preferably, in step S1, the pretreated positive electrode active material and polypropylene are mixed evenly at a mass ratio of 1:10, placed in a semi-batch pyrolysis device, and pyrolyzed at 650°C under a nitrogen atmosphere for 2 hours at a heating rate of 10°C / min to obtain the pyrolysis product.

[0063] Preferably, in step S2, the pyrolysis product is soaked in water at room temperature and stirred for 1 hour;

[0064] Preferably, in step S3, the lithium carbonate solution is concentrated and crystallized at 90°C;

[0065] Preferably, in step S4, crude lithium carbonate and water are mixed at a solid-liquid ratio of 1g:15mL;

[0066] Preferably, in step S6, the pure lithium bicarbonate solution is heated to 80°C for 30 minutes.

[0067] Preferably, in step S9, the pH of the filtrate is adjusted to 8 with ammonia water, and 20% ammonium persulfate is added and reacted at 80°C for 1 hour.

[0068] In this embodiment, the gas generated during pyrolysis can be recycled, reducing waste gas emissions. Lithium exists in the form of carbonate and can be directly immersed in water, avoiding the use of large amounts of chemical reagents and reducing the difficulty of wastewater treatment. Lithium is recycled in the form of battery-grade lithium carbonate. As the core basic raw material for lithium battery cathode materials, lithium carbonate can be reused in the production of lithium batteries, realizing the recycling of lithium resources. It can also recover valuable metals such as nickel and cobalt through subsequent processing, improving resource utilization, avoiding the high energy consumption problem of pre-concentrated carbon dioxide in traditional processes, and improving product purity.

[0069] This invention also provides equipment for recycling waste lithium battery cathode active materials to prepare battery-grade lithium carbonate.

[0070] First embodiment:

[0071] Please see Figures 1 to 7 Equipment for recycling waste lithium battery positive electrode active materials to prepare battery-grade lithium carbonate, including reaction tank 1, sealing cover 2, drive mechanism 3 and tapping mechanism 4;

[0072] The drive mechanism 3 includes a mounting frame 31 fixed to the inner wall of the reaction tank 1. A rotating shaft 32 is vertically rotatably connected inside the mounting frame 31. A drive gear 33 is connected to the peripheral side of the rotating shaft 32 and the bottom of the mounting frame 31 via a keyway. Two rotating shafts 34 are vertically rotatably connected inside the mounting frame 31 and on both sides of the rotating shaft 32. A driven gear 35 is fixed to the peripheral side of the two rotating shafts 34 and the bottom of the mounting frame 31. The two driven gears 35 mesh with the drive gear 33. A cam 36 is fixed to the peripheral side of the two rotating shafts 34 and inside the mounting frame 31.

[0073] The tapping mechanism 4 includes two connecting plates 41 fixed inside the left side of the mounting frame 31. A reciprocating rod 42 is vertically slidably connected inside the two connecting plates 41. A spring 43 is sleeved on the circumferential side of the reciprocating rod 42 and at the bottom of the bottom connecting plate 41. A tapping frame 44 is fixed at the bottom end of the reciprocating rod 42. A wire mesh 45 is provided on the inner side of the tapping frame 44. A connecting plate 46 is rotatably connected to the left side of the back wall of the mounting frame 31. A rotating wheel 47 is rotatably connected to the right side of the connecting plate 46 and at the bottom of the left cam 36. The surface of the rotating wheel 47 is in contact with the bottom of the left cam 36. The left side of the connecting plate 46 is located inside the reciprocating rod 42. A snap-fit ​​member 48 is provided inside the reciprocating rod 42 and inside the connecting plate 46.

[0074] The reciprocating rod 42 has a through groove for the movement of the connecting plate 46. The left side of the connecting plate 46 has a slot for cooperating with the snap-fit ​​part 48. The tapping mechanism 4 has two sets of mirror images on the left and right sides. The sealing cover 2 is fixedly connected to the top of the reaction tank 1 by bolts.

[0075] Please combine Figures 4 to 7 The drive motor 73 is started, and the drive motor 73 rotates, which drives the rotating shaft 32 to rotate. The rotating shaft 32 rotates, which drives the drive gear 33 to rotate. The drive gear 33 rotates, which drives the two driven gears 35 and the rotating shaft 34 to rotate. The two rotating shafts 34 then drive the two cams 36 to rotate. When the left cam 36 rotates, the convex position of the cam 36 will change. Under the elastic force of the spring 43, the reciprocating rod 42 will drive the beater 44 and the wire mesh 45 to move downward. During the downward movement of the reciprocating rod 42, the connecting plate 46 is limited by the snap-fit ​​piece 48. The reciprocating rod 42 will simultaneously drive the left side of the connecting plate 46 to move downward, so that the right side of the connecting plate 46 drives the rotating wheel 47 to tilt upward. The top of the rotating wheel 47 is always in contact with the bottom of the cam 36. When the concave position of the bottom of the cam 36 contacts the rotating wheel 47, the reciprocating rod 42 will drive the beater 44 to descend to the lowest height. The downward movement of the beater 44 will beat the liquid surface.

[0076] Furthermore, as the cam 36 continues to rotate, when the protruding part of the cam 36 contacts the rotating wheel 47, the rotating wheel 47 will simultaneously press the right side of the connecting plate 46 downward, causing the left side of the connecting plate 46 to tilt upward. The connecting plate 46, through the snap-fit ​​part 48, will then drive the reciprocating rod 42 and the striking frame 44 to move upward, causing the spring 43 to contract.

[0077] Preferably, by continuously rotating the two cams 36 in conjunction with the spring 43, the two beaters 44 can move up and down reciprocally to beat the liquid surface. When one of the cams 36 is rotated 180 degrees and installed, the rotation of the two cams 36 can cause the two beaters 44 to move up and down alternately to beat the liquid surface.

[0078] Preferably, during the carbonization reaction, when microbubbles rise in the slurry, they come into contact with suspended solid particles. Because there are tiny hydrophobic areas on the particle surface, the bubbles will spontaneously adsorb onto the particle surface, forming scum on the liquid surface. Furthermore, during the reaction, a large number of bubbles will exist on the liquid surface. By moving the beater 44 downwards, the scum can be pressed back into the slurry, and the bubbles can be broken.

[0079] In this embodiment, the rotation of the rotating shaft 32 drives the rotation of the driving gear 33, which in turn drives the driven gear 35, the rotating shaft 34, and the cam 36 to rotate. With the continuous rotation of the cam 36, in conjunction with the connecting plate 46, the rotating wheel 47, the reciprocating rod 42, and the spring 43, the two beating frames 44 can drive the wire mesh 45 to move up and down reciprocally, beating the liquid surface and forcibly pressing the scum back into the slurry. At the same time, the mesh structure of the wire mesh 45 will break up the agglomerated scum particles, preventing them from re-aggregating, allowing the encapsulated lithium carbonate microcrystals to be fully exposed and come into contact with the flue gas bubbles to complete the carbonization reaction. The static gas film that easily forms on the surface of the carbonization reaction liquid, as well as the gas film in the contact area between the tank wall and the liquid surface, will isolate CO2 from contact with the slurry. By beating up and down by the beating frames 44, the static gas film on the liquid surface is torn apart, allowing the combustion exhaust gas to directly enter the slurry.

[0080] Second embodiment:

[0081] Please see Figures 8 to 11 An auxiliary mechanism 5 is fixedly provided on the left side of the top of the sealing cover 2. The auxiliary mechanism 5 includes a storage cylinder 51 fixedly provided on the left side of the top of the sealing cover 2. The top end of the reciprocating rod 42 passes through the bottom of the sealing cover 2 and extends into the interior of the storage cylinder 51. A piston 52 is fixedly provided at the top end of the reciprocating rod 42 and inside the storage cylinder 51. An extraction tube 53 is connected to the top of the storage cylinder 51. A delivery tube 54 is connected to the left side of the storage cylinder 51. The bottom end of the delivery tube 54 passes through the top of the sealing cover 2 and extends into the interior of the reaction tank 1.

[0082] A swing spraying mechanism 6 is fixedly provided at the bottom front side of the mounting bracket 31. The swing spraying mechanism 6 includes two mounting brackets 61 fixedly provided at the bottom front side of the mounting bracket 31. Spray pipes 62 are rotatably connected to the interior of the two mounting brackets 61. Multiple nozzles 63 are connected to the surface of the spray pipes 62. A drive toothed plate 64 is fixedly provided on the inner side of the beater 44. A swing gear 65 is fixedly provided on the surface of the spray pipes 62. The swing gear 65 meshes with the drive toothed plate 64.

[0083] The auxiliary mechanism 5 is arranged in two sets on the left and right sides, the oscillating spraying mechanism 6 is arranged in two sets in front and behind, the storage cylinder 51 is used to store deionized water or defoamer, and the delivery pipe 54 is connected to the spraying pipe 62.

[0084] Preferably, both the extraction pipe 53 and the delivery pipe 54 are provided with one-way valves.

[0085] Please combine Figure 8 and Figure 9 When the reciprocating rod 42 moves downward, it will simultaneously drive the piston 52 to move downward. The downward movement of the piston 52 will allow the extraction tube 53 to extract deionized water or defoamer.

[0086] Furthermore, when the reciprocating rod 42 returns to its original position, it will cause the piston 52 to slide upward in the storage cylinder 51, thereby delivering deionized water or defoamer through the delivery pipe 54 to the spray pipe 62 and spraying it out through the nozzle 63.

[0087] Please combine Figure 10 and Figure 11 When the reciprocating rod 42 drives the beater 44 to move downward, the beater 44 will simultaneously drive the drive tooth plate 64 to move downward. The drive tooth plate 64 moving downward will drive the swing gear 65 to rotate counterclockwise. The counterclockwise rotation of the swing gear 65 will drive the spray pipe 62 and the nozzle 63 to rotate counterclockwise, thereby transferring the spraying direction of the nozzle 63 from the liquid surface at the bottom of the beater 44 to the inner wall of the reaction tank 1 to rinse the inner wall.

[0088] Furthermore, when the reciprocating rod 42 drives the beater 44 to reset upwards, the beater 44 will simultaneously drive the drive gear plate 64 to move upwards, causing the swing gear 65 to drive the spray pipe 62 to rotate clockwise, thus resetting the nozzle 63.

[0089] Furthermore, when one of the cams 36 is rotated 180 degrees and installed, the two beaters 44 move up and down alternately, and the two spray pipes 62 also spray alternately back and forth.

[0090] In this embodiment, after the reciprocating rod 42 moves downward, it moves upward again under the rotation of the cam 36. The reciprocating rod 42 will drive the piston 52 and the beater 44 to move upward. The piston 52 moves upward, thereby conveying deionized water or defoamer to the spray pipe 62 through the delivery pipe 54 and spraying it out through the nozzle 63. The upward movement of the beater 44 will simultaneously drive the drive tooth plate 64 to move upward, causing the swing gear 65 to drive the spray pipe 62 and the nozzle 63 to rotate clockwise, spraying deionized water or defoamer from the inner wall of the reaction tank 1 to the liquid surface under the beater 44. When the foam or scum is more severe, the beater frequency is higher, the fluid volume pumped by the piston 52 is greater, and the spray defoaming force is also increased simultaneously, realizing the adaptive adjustment of the degree of foam or scum and the treatment force.

[0091] Third embodiment:

[0092] Please see Figure 1 , Figure 2 and Figure 12 A stirring mechanism 7 is fixedly provided on the surface of the rotating shaft 32. The stirring mechanism 7 includes a stirring paddle 71 fixedly provided on the surface of the rotating shaft 32. A mounting base 72 is fixedly provided on the top of the sealing cover 2. A drive motor 73 for driving the rotating shaft 32 to rotate is provided on the top of the mounting base 72. The rotating shaft 32 is rotatably connected to the sealing cover 2.

[0093] The bottom of both sides of the reaction tank 1 is connected to the feed pipe 8, the top of the right side of the reaction tank 1 is connected to the exhaust pipe 9, the right side of the bottom of the reaction tank 1 is connected to the discharge pipe 10, the bottom of the reaction tank 1 is fixedly provided with the support leg 11, and multiple air inlet pipes 12 are arranged longitudinally inside the reaction tank 1, and each of the multiple air inlet pipes 12 is provided with an air outlet nozzle 13.

[0094] Preferably, the intake pipe 12 is used to transport combustion exhaust gas;

[0095] Please combine Figure 12 Start the drive motor 73. The drive motor 73 rotates and drives the rotating shaft 32 to rotate. When the rotating shaft 32 drives the drive gear 33 to rotate, it will simultaneously drive the agitator 71 to rotate. The rotation of the agitator 71 will mix the slurry with the combustion exhaust gas.

[0096] In this embodiment, the exhaust nozzle 13 penetrates deep into the bottom layer of the slurry, and the combustion exhaust gas diffuses upward in the form of microbubbles, resulting in a longer contact path with the slurry and a larger contact area. The rotating shaft 32 drives the stirring paddle 71 to rotate, and the rotation of the stirring paddle 71 mixes the slurry and the combustion exhaust gas.

[0097] Please refer to the reference again. Figures 1 to 12 The working principle of the equipment for recycling and preparing battery-grade lithium carbonate from waste lithium battery positive electrode active materials provided by this invention is as follows:

[0098] In step S1, lithium carbonate slurry is uniformly fed into reaction tank 1 through two feed pipes 8. Then, the regulating valve of air inlet pipe 12 is opened to send the pretreated combustion exhaust gas into the bottom of reaction tank 1. Microbubbles are formed through air outlet nozzle 13 and evenly dispersed in the slurry. Then, drive motor 73 is started. Drive motor 73 rotates and drives rotating shaft 32 to rotate. Rotating shaft 32 drives stirring paddle 71 to rotate. The rotation of stirring paddle 71 mixes the slurry and combustion exhaust gas.

[0099] In step S2, when the rotating shaft 32 rotates, it will simultaneously drive the driving gear 33 to rotate. The rotation of the driving gear 33 will drive the two driven gears 35 and the rotating shaft 34 to rotate. The two rotating shafts 34 will then drive the two cams 36 to rotate. When the cams 36 rotate, the convex position of the cams 36 will change. Under the elastic force of the spring 43, the reciprocating rod 42 will drive the beater 44 and the wire mesh 45 to move downward. During the downward movement of the reciprocating rod 42, the connecting plate 46 will be limited by the snap-fit ​​piece 48. The reciprocating rod 42 will simultaneously drive the left side of the connecting plate 46 to move downward, so that the right side of the connecting plate 46 will drive the rotating wheel 47 to tilt upward, so that the top of the rotating wheel 47 is always in contact with the bottom of the cam 36. When the concave position of the bottom of the cam 36 is in contact with the rotating wheel 47, the reciprocating rod 42 will drive the beater 44 to descend to the lowest height. By descending the beater 44, the liquid surface will be beaten.

[0100] As the cam 36 continues to rotate, when the protruding part of the cam 36 contacts the rotating wheel 47, the rotating wheel 47 will simultaneously press the right side of the connecting plate 46 downward, causing the left side of the connecting plate 46 to tilt upward. The connecting plate 46, through the snap-fit ​​part 48, will drive the reciprocating rod 42 and the beater 44 to move upward, causing the spring 43 to contract. Through the continuous rotation of the two cams 36, the two beaters 44 will move up and down reciprocally to beat the liquid surface.

[0101] In step S3, when the reciprocating rod 42 moves downward, it will simultaneously drive the piston 52 to move downward. The piston 52 moves downward so that the extraction tube 53 can extract deionized water or defoamer.

[0102] When the reciprocating rod 42 returns to its original position, it will drive the piston 52 to slide upward in the storage cylinder 51, and deliver deionized water or defoamer through the delivery pipe 54 to the spray pipe 62, and spray it out through the nozzle 63.

[0103] In step S4, when the reciprocating rod 42 drives the beater 44 to move downward, the beater 44 will simultaneously drive the drive tooth plate 64 to move downward. The downward movement of the drive tooth plate 64 drives the swing gear 65 to rotate counterclockwise. The counterclockwise rotation of the swing gear 65 drives the spray pipe 62 and the nozzle 63 to rotate counterclockwise, thereby transferring the spraying direction of the nozzle 63 from the liquid surface at the bottom of the beater 44 to the inner wall of the reaction tank 1 to rinse the inner wall.

[0104] When the reciprocating rod 42 drives the beater 44 to reset upwards, the beater 44 will simultaneously drive the drive gear plate 64 to move upwards, causing the swing gear 65 to drive the spray pipe 62 to rotate clockwise, thus resetting the nozzle 63.

[0105] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A process for recycling waste lithium battery cathode active materials to prepare battery-grade lithium carbonate, characterized in that, Includes the following steps: Step S1: Mix the pretreated positive electrode active material with polypropylene in a certain proportion, and place it in a semi-batch pyrolysis device for pyrolysis treatment to obtain pyrolysis products. Step S2: The pyrolysis product is leached in water and filtered to obtain a lithium carbonate solution and residue; Step S3: Concentrate and crystallize the lithium carbonate solution to obtain crude lithium carbonate; Step S4: Mix crude lithium carbonate and water in a certain proportion and stir to obtain lithium carbonate slurry; Step S5: The combustion exhaust gas is introduced into the lithium carbonate slurry and carbonization reaction is carried out in the reaction tank 1. After filtration, a pure lithium bicarbonate solution and residue 1 are obtained. Step S6: Heat the pure lithium bicarbonate solution, dry and pulverize it to obtain battery-grade lithium carbonate; Step S7: Grind the residue obtained in step S2 and perform magnetic separation to obtain magnetic and non-magnetic materials. The magnetic material is mainly nickel-cobalt alloy, and the non-magnetic material is mainly manganese oxide. Step S8: Mix the non-magnetic substance and residue 1, then acid-leach, purify, and filter to obtain the filtrate; Step S9: Adjust the pH of the filtrate, add ammonium persulfate to react, wash, dry, and calcine to obtain solid manganese dioxide.

2. The process for recycling waste lithium battery cathode active materials to prepare battery-grade lithium carbonate according to claim 1, characterized in that, In step S1, the generated gases mainly include reducing gases such as hydrogen and methane, which can circulate in the pyrolysis device to promote the reduction of the positive electrode active material. In step S5, the combustion exhaust gas comes from a thermal power plant or industrial boiler and contains carbon dioxide gas. In step S6, carbon dioxide will be released, which can be captured by a gas collection device, purified, and reused in the carbonization reaction or other industrial applications.

3. Equipment for recycling waste lithium battery cathode active materials to prepare battery-grade lithium carbonate, characterized in that, The equipment for recycling and preparing battery-grade lithium carbonate is used in the process for recycling and preparing battery-grade lithium carbonate as described in any one of claims 1-2, and includes a reaction tank, a sealing cap, a drive mechanism, and a tapping mechanism. The drive mechanism includes a mounting frame fixed to the inner wall of the reaction tank. A rotating shaft is vertically rotatably connected inside the mounting frame. A drive gear is connected to the circumferential side of the rotating shaft and the bottom of the mounting frame via a keyway. Two rotating shafts are vertically rotatably connected inside the mounting frame and on both sides of the rotating shaft. A driven gear is fixed to the circumferential side of the two rotating shafts and the bottom of the mounting frame. The two driven gears mesh with the drive gear. A cam is fixed to the circumferential side of the two rotating shafts and inside the mounting frame. The striking mechanism includes two connecting plates fixed inside the left side of the mounting frame. A reciprocating rod is vertically slidably connected inside the two connecting plates. A spring is sleeved on the circumferential side of the reciprocating rod and at the bottom of the bottom connecting plate. A striking frame is fixed at the bottom end of the reciprocating rod. A wire mesh is provided on the inner side of the striking frame. A connecting plate is rotatably connected to the left side of the back wall of the mounting frame. A rotating wheel is rotatably connected to the right side of the connecting plate and at the bottom of the left cam. The surface of the rotating wheel is in contact with the bottom of the left cam. The left side of the connecting plate is located inside the reciprocating rod. A snap-fit ​​component is provided inside the reciprocating rod and inside the connecting plate.

4. The equipment for recycling waste lithium battery cathode active materials to prepare battery-grade lithium carbonate according to claim 3, characterized in that, The reciprocating rod has a through groove for the movement of the connecting plate, and the left side of the connecting plate has a slot for use with the snap-fit ​​component. The tapping mechanism has two sets arranged in a mirror image on the left and right sides. The sealing cover is fixedly connected to the top of the reaction tank by bolts.

5. The equipment for recycling waste lithium battery cathode active materials to prepare battery-grade lithium carbonate according to claim 3, characterized in that, An auxiliary mechanism is fixedly provided on the left side of the top of the sealing cover. The auxiliary mechanism includes a storage cylinder fixedly provided on the left side of the top of the sealing cover. The top end of the reciprocating rod passes through the bottom of the sealing cover and extends into the interior of the storage cylinder. A piston is fixedly provided on the top end of the reciprocating rod and inside the storage cylinder. An extraction tube is connected to the top of the storage cylinder. A delivery tube is connected to the left side of the storage cylinder. The bottom end of the delivery tube passes through the top of the sealing cover and extends into the interior of the reaction tank.

6. The equipment for recycling waste lithium battery cathode active materials to prepare battery-grade lithium carbonate according to claim 5, characterized in that, A swing spraying mechanism is fixedly provided at the bottom of the front side of the mounting frame. The swing spraying mechanism includes two mounting brackets fixedly provided at the bottom of the front side of the mounting frame. Spray pipes are rotatably connected to the inside of the two mounting brackets. Multiple nozzles are connected to the surface of the spray pipes. A drive toothed plate is fixedly provided on the inner side of the beater frame. A swing gear is fixedly provided on the surface of the spray pipes. The swing gear meshes with the drive toothed plate.

7. The equipment for recycling waste lithium battery cathode active materials to prepare battery-grade lithium carbonate according to claim 6, characterized in that, The auxiliary mechanism is arranged in two sets on the left and right sides, the oscillating spraying mechanism is arranged in two sets on the front and back, the storage cylinder is used to store deionized water or defoamer, and the delivery pipe is connected to the spraying pipe.

8. The equipment for recycling waste lithium battery cathode active materials to prepare battery-grade lithium carbonate according to claim 3, characterized in that, A stirring mechanism is fixedly provided on the surface of the rotating shaft. The stirring mechanism includes a stirring paddle fixedly provided on the surface of the rotating shaft. A mounting base is fixedly provided on the top of the sealing cover. A drive motor for driving the rotating shaft to rotate is provided on the top of the mounting base. The rotating shaft is rotatably connected to the sealing cover.

9. The equipment for recycling waste lithium battery positive electrode active materials to prepare battery-grade lithium carbonate according to claim 3, characterized in that, The bottom of both sides of the reaction tank is connected to a feed pipe, the top of the right side of the reaction tank is connected to an exhaust pipe, the right side of the bottom of the reaction tank is connected to a discharge pipe, the bottom of the reaction tank is fixed with a support leg, and multiple air inlet pipes are arranged longitudinally inside the reaction tank, with an air outlet nozzle at the top of each of the multiple air inlet pipes.

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