Method and equipment for efficiently stripping positive electrode material and aluminum foil of scrapped lithium ion battery

Abstract

The invention provides an efficient stripping method for a positive electrode material and an aluminum foil of a scrapped lithium ion battery, which comprises the following steps: aeration stripping: putting a battery pole piece material into aeration flotation equipment, adding a certain amount of stripping agent, opening an aeration valve to start aeration, stripping the positive electrode material from the aluminum foil in the pole piece material, and then closing the aeration valve; flotation separation: adjusting the distance between a stirring paddle and a separation net, starting stirring, adding a foaming agent, stirring for a certain time, starting aeration, reducing the distance between the stirring paddle and the separation net when the aluminum foil does not float, continuing stirring and aeration, collecting an upper-layer material as the aluminum foil, and collecting a lower-layer material as a positive active material; wherein the aeration flotation equipment comprises an air flotation reaction kettle, a stirring paddle, an aeration disc and a separation net, the separation net is arranged on the aeration disc, the separation net and the aeration disc are arranged at the bottom of the air flotation reaction kettle, the stirring paddle is arranged in the air flotation reaction kettle, and the distance between the stirring paddle and the separation net can be adjusted.

Description

Technical Field

[0001] The invention relates to the technical field of recycling scrapped lithium-ion battery materials, and in particular to a method for efficiently stripping anode materials and aluminum foil of scrapped lithium-ion batteries, and equipment for realizing efficient stripping of anode materials and aluminum foil of scrapped lithium-ion batteries. Background Art

[0002] In recent years, the country has promoted new energy vehicles, and the output of electric vehicles, lithium-ion battery production and scrapping have increased. At present, the battery recycling technology is mainly dry and wet recycling. The former recovers valuable metal elements by incineration in a high-temperature furnace, which has problems of environmental pollution and low recovery rate. The latter recovers elements by chemical leaching, precipitation, and extraction, with a long process and high cost. Different from dry and wet recycling, direct repair and regeneration technology has attracted more and more attention from research institutions and recycling companies. This method is to separate the battery materials, supplement the missing elements, restore the material structure, etc. through a shorter repair process, so as to achieve the recycling of battery materials, retain the original performance of the materials to the greatest extent, and has the advantages of low cost, good quality, and environmental protection. For example, CN218215435U discloses a reactor for battery pole piece stripping, including a box body, the inner cavity of the box body is used as a space for pole piece reaction; a stirring device is arranged at the bottom of the box body, which is used to drive the reaction liquid inside the box body to rotate, generate centrifugal force to separate and crush the pole pieces; at least two filter plates are fixed in the inner cavity of the box body through a plurality of branch rings arranged on the inner wall of the box body. However, the device only separates the black material and the aluminum foil by stirring and crushing the black material of the electrode. The aluminum foil is also easily broken during the process, resulting in a high level of aluminum impurities in the black material.

[0003] Since the positive electrode active material is tightly adhered to the aluminum foil through the binder, the direct repair and regeneration technology of battery materials has the problem of difficulty in separating the positive electrode material from the aluminum foil during industrial expansion, and the aluminum content of the regenerated repair material is relatively high. Although the aluminum content problem can be improved by using methods such as cyclone sorting and gravity separation, the yield is difficult to guarantee. It is urgent to develop an aluminum foil stripping technology and supporting equipment suitable for industrial expansion. Summary of the invention

[0004] The purpose of the present invention is to solve at least one of the following technical problems:

[0005] (1) The positive electrode material is the most valuable part of battery recycling. It is in the form of positive electrode sheets, mixed with conductive carbon and binder and adhered to the aluminum current collector. Since the material properties of this type of electrode are not damaged, it can be directly reused after stripping, composition regulation and heat treatment without wet refining, and has extremely high cascade utilization value. Among them, the stripping process is the key to reducing impurities. At present, the mainstream stripping methods are mainly divided into aerobic calcination, anaerobic calcination combined with crushing cyclone separation, etc., which have high energy consumption, high cost and difficult to control impurities. Physical solvent stripping has low cost, short process and few impurities, especially for reducing the content of aluminum impurities. It is of great significance to conduct in-depth research and consider engineering scale-up.

[0006] (2) Scrapped positive electrode sheets are mainly composed of positive electrode materials and aluminum foil, which have similar density and size. After solvent stripping, the positive electrode materials and aluminum foil are mixed and difficult to separate in industry. There is little related research, and it is necessary to develop and customize highly adaptable equipment.

[0007] To this end, the present invention applies the flotation method to the separation of positive electrode materials and aluminum foil, adds a foaming agent, improves the separation efficiency, takes into account the separation effect, efficiency and cost, and designs supporting equipment suitable for industrial use.

[0008] In one aspect, the present invention provides an efficient stripping method for scrapped lithium-ion battery positive electrode material and aluminum foil, comprising the following steps:

[0009] Aeration stripping: Put the scrapped lithium-ion battery pole pieces into the aeration flotation equipment, add a certain amount of stripping agent, open the aeration valve to start aeration, realize the stripping of the positive electrode material and the aluminum foil in the pole piece, and then close the aeration valve;

[0010] Flotation separation: After adjusting the distance between the stirring paddle and the isolation net, start stirring, add a frother, and start aeration after stirring for a certain period of time. When the aluminum foil no longer floats, lower the distance between the stirring paddle and the isolation net, continue stirring and aerating, collect the upper material as aluminum foil, and collect the lower material as positive electrode active material;

[0011] The aeration flotation equipment comprises an air flotation reactor, an agitator, an aeration plate and an isolation net. The isolation net is arranged on the aeration plate and together with the aeration plate, the agitator is arranged inside the air flotation reactor. The distance between the agitator and the isolation net can be adjusted.

[0012] In a specific embodiment of the present application, the aeration stripping step also has at least one of the following technical features:

[0013] (1) The preparation process of the scrapped lithium-ion battery electrode sheet material comprises: discharging and disassembling the scrapped lithium-ion battery to obtain a positive electrode sheet material, and then cutting the positive electrode sheet material into square sizes;

[0014] Preferably, the side length of the square pole sheet is 3-10 cm;

[0015] (2) The amount of the stripping agent added is such that the solid content of the slurry is 1-5%;

[0016] Preferably, the solid content is 2-4%;

[0017] (3) The temperature of the stripping agent is 40-90°C;

[0018] Preferably, the temperature of the stripping agent is 50-70°C;

[0019] (4) The aeration gas flow rate of the aeration flotation equipment is 20-50 L / min;

[0020] (5) The mesh of the isolation net in the aeration flotation equipment is square;

[0021] Preferably, the side length of the square is 0.4-1 cm;

[0022] (6) The positive electrode material in the electrode sheet is one of lithium iron phosphate, ternary material, and lithium cobalt oxide;

[0023] (7) The state of the electrode is one of an uninjected electrode, an injected electrode, and a cycle-failed electrode.

[0024] In this application, the positive electrode sheet is cut into squares to control variables. The squares are easy to cut to control the size and eliminate the interference of the difference in buoyancy of the irregular shapes. However, in the actual production process, the shear shape of the positive electrode sheet can be any shape, not necessarily a square.

[0025] Similarly, in the present application, the mesh openings of the isolation net in the aeration flotation device may also be of any shape and are not necessarily required to be square.

[0026] In a specific embodiment of the present application, the stripping agent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, water, and oxalic acid.

[0027] Preferably, the stripping agent contains water; more preferably, the stripping agent is water.

[0028] In a specific embodiment of the present application, in the flotation separation step, the initial distance between the stirring paddle and the isolation net is 3-6 cm, and the rotation speed of the stirring paddle is 10-100 r / min.

[0029] In a specific embodiment of the present application, when the aluminum foil no longer floats, the distance between the stirring paddle and the isolation net is lowered to 0.5-2.5 cm, while the rotation speed of the stirring paddle is 10-100 r / min, and the aeration gas flow rate is 10-40 L / min.

[0030] In the present application, the stirring paddle can realize the functions of pause, speed adjustment, and lifting and lowering. The pause and speed adjustment can improve the floating rate of aluminum foil. The lifting and lowering function ensures that the stirring paddle is adjusted to the middle in the early stage of flotation to reduce the disturbance to the bottom and improve the floating rate of aluminum. In the later stage of flotation, the stirring paddle is lowered to cooperate with the isolation net, and the water flow is used to break up the positive electrode material to improve the yield of the positive electrode material.

[0031] In a specific embodiment of the present application, the foaming agent is one or more of sodium dodecylbenzenesulfonate and sodium dodecanesulfonate.

[0032] In a specific embodiment of the present application, the amount of the foaming agent added is 0.002-0.02% of the mass of the stripping agent, preferably 0.005-0.01%.

[0033] In a specific embodiment of the present application, in the flotation separation step, it is necessary to supplement the stripping agent during the aeration process, and the amount of the supplemented stripping agent is 0.5-2 L / min.

[0034] In a specific embodiment of the present application, the collected positive electrode active material is dried in an inert atmosphere, then crushed, and then the crushed material is calcined in an inert atmosphere to obtain a positive electrode material repair material;

[0035] Preferably, the drying temperature is 80-120°C and the drying time is 2-8h;

[0036] Preferably, the crushing is to 200-800 mesh;

[0037] Preferably, the calcination temperature is 500-800° C. and the calcination time is 2-20 h.

[0038] In a specific embodiment of the present application, the aeration plate is made of nano-microporous aeration tubes, which are tied to a fixing frame with the help of fixing buckles to make the aeration plate, and placed on a support table. The support table is used to support the aeration plate fixing frame, and the aeration plate can be disassembled and replaced. The aeration tubes are connected to the aeration right air inlet and the aeration left air inlet to achieve aeration.

[0039] In a specific embodiment of the present application, the stirring paddle is a cross-shaped stirring paddle with a wall scraper, and a soft wall scraper brush is attached to the edge of the stirring paddle; preferably, the stirring paddle is attached with a soft wall scraper brush made of polytetrafluoroethylene material. The wall scraper function is used to solve the problem of aluminum foil sticking to the wall, thereby improving the floating rate of aluminum foil.

[0040] In the present application, an isolation net is placed on the aeration plate, and the positive electrode material is broken up and leaked into the net by utilizing the shearing effect of the water flow generated by the stirring paddle and the isolation net at the bottom, and then discharged from the discharge port at the bottom of the kettle to achieve the collection of the positive electrode material.

[0041] In a specific embodiment of the present application, the aeration flotation equipment further includes a motor, a scraper and an overflow tank. The overflow tank is arranged above the flotation reactor, and the overflow tank has an overflow tank discharge port. The aluminum foil is discharged from the overflow tank discharge port along with the foam generated by flotation through the overflow tank; the scraper is arranged above the overflow tank, and the scraper can rotate, and the rotating scraper can prevent the foam from overflowing the equipment. The motor is connected to the stirring paddle through a stirring rod to provide power for the stirring paddle.

[0042] The aeration flotation equipment further includes a reactor bottom cover, which is arranged below the flotation reactor and is used for discharging the lower layer of materials. The reactor bottom cover is connected to the flotation reactor through a bottom cover switch cylinder, and the bottom cover of the reactor and the flotation reactor are opened and closed by the extension and contraction of the bottom cover switch cylinder. The reactor bottom cover is provided with a discharge port at the bottom of the reactor, which further reduces aluminum impurities. An anti-blocking jet nozzle is arranged near the discharge port at the bottom of the reactor, and the bottom is blocked by intermittently spraying high-pressure gas.

[0043] The aeration flotation equipment further comprises a steam heating jacket for passing steam to heat the kettle body. The steam heating jacket has a jacket steam heating inlet and a jacket steam heating outlet, wherein the jacket steam heating inlet is arranged at the lower part of the steam heating jacket, and the jacket steam heating outlet is arranged at the upper part of the steam heating jacket.

[0044] On the other hand, the present application provides an aeration flotation device, which is used to efficiently peel off the positive electrode material and aluminum foil of scrapped lithium-ion batteries, including an air flotation reactor, an agitator, an aeration plate and an isolation net, wherein the isolation net is arranged on the aeration plate and together with the aeration plate at the bottom of the air flotation reactor, the agitator is arranged inside the air flotation reactor, and the distance between the agitator and the isolation net can be adjusted.

[0045] The device has the technical features as described above and will not be described in detail here.

[0046] Beneficial effects:

[0047] (1) The present invention realizes the optimization of industrial scale-up of the scrap lithium-ion battery material recovery and stripping process, designs a highly adaptable device for flotation separation of aluminum foil, and greatly reduces the aluminum impurity content of the recycled repair material.

[0048] (2) After the positive electrode material and the aluminum foil are peeled off, the aluminum foil is separated by flotation. The separation rate of the aluminum foil is about 95%, and a small amount of aluminum foil still remains. In order to further reduce the impurities in the positive electrode material product, combined with the fact that the positive electrode material is more fragile than the aluminum foil, the present invention improves the flotation equipment, uses a nano-microporous aeration tube, and uses a fixing buckle to tie it to a fixing frame to make an aeration plate. The aeration tube is connected to the upper aeration right air inlet and the aeration left air inlet to achieve aeration, and an isolation net is placed on the aeration plate. The water flow generated by the stirring paddle and the shearing effect of the bottom isolation net are used to break the positive electrode material and leak it under the net, and the material is discharged from the discharge port at the bottom of the kettle to achieve the collection of the positive electrode material, further reducing the aluminum impurities. At the same time, an anti-blocking jet nozzle is set to intermittently spray high-pressure gas to prevent bottom blockage.

[0049] (3) Aluminum foil is thin and easy to stick to the wall under stirring, resulting in poor floating effect. The present invention adopts a cross-shaped stirring paddle with wall scraping, and the edge of the stirring paddle is equipped with a soft scraping brush made of polytetrafluoroethylene material. The wall scraping function is used to solve the problem of aluminum foil sticking to the wall, thereby improving the floating rate of aluminum foil. The aluminum foil is discharged from the overflow tank outlet through the overflow tank along with the foam generated by flotation, and the rotating scraper can prevent the foam from overflowing the equipment.

[0050] (4) During the flotation process of the present invention, the stirring paddle can realize the functions of pause, speed adjustment, and lifting and lowering. The pause and speed adjustment can improve the flotation rate of aluminum foil. The upgrading function ensures that the stirring paddle is adjusted to the middle in the early stage of flotation to reduce the disturbance to the bottom and improve the flotation rate of aluminum. In the later stage of flotation, the stirring paddle is lowered to cooperate with the isolation net, and the positive electrode material is broken up by the water flow to improve the yield of the positive electrode material. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a structural schematic diagram of an aeration flotation device provided by the present invention;

[0052] Figure 2 It is a structural schematic diagram of an aeration net provided by the present invention;

[0053] For the convenience of illustration, the isolation net 5 is only partially drawn, but in actual application, the isolation net 5 is the same size as the aeration plate 6;

[0054] Figure 3 It is a structural schematic diagram of a stirring paddle provided by the present invention;

[0055] Figure 4 It is a schematic diagram of a device for efficiently peeling off the positive electrode material and aluminum foil of a scrapped lithium-ion battery provided by the present invention;

[0056] Figure 5 It is a process flow chart of a method for efficiently stripping a scrapped lithium-ion battery positive electrode material and aluminum foil provided by the present invention;

[0057] Among them, 1-frequency conversion motor, 2-scraper, 3-overflow trough, 4-stirring paddle, 5-isolation net, 6-aeration plate, 61-aeration pipe, 7-aeration pipe fixing frame, 8-support platform, 9-bottom cover switch cylinder, 10-floatation reactor, 11-reactor bottom cover, 12-steam heating jacket, 41-stirring paddle scraping soft brush, 71-aeration pipe fixing buckle, N1-overflow trough discharge port, N2-kettle bottom discharge port, N3-jacket steam heating outlet, N4-jacket steam heating inlet, N5-anti-blocking material jet outlet, N6-aeration left inlet, N7-aeration right inlet. DETAILED DESCRIPTION

[0058] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0059] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0060] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0061] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0063] The present invention provides an aeration flotation device, such as Figure 1 As shown, the aeration flotation equipment is used to efficiently strip the positive electrode materials and aluminum foil of scrapped lithium-ion batteries, including an air flotation reactor 10, a stirring paddle 4, an aeration plate 6 and an isolation net 5. The isolation net 5 is arranged on the aeration plate 6 and is arranged together at the bottom of the air flotation reactor 10. The stirring paddle 4 is arranged inside the air flotation reactor 10, and the distance between the stirring paddle 4 and the isolation net 5 can be adjusted.

[0064] like Figure 2 As shown, the aeration plate 6 is made by using a nano-microporous aeration tube 61, which is tied to the aeration tube fixing frame 7 by means of an aeration tube fixing buckle 71, and is placed on a support platform 8. The support platform 8 is used to support the aeration plate fixing frame 7, and the aeration plate 6 can be disassembled and replaced. The aeration tube 61 connects the aeration right air inlet N7 and the aeration left air inlet N6 to achieve aeration. The mesh of the isolation net 5 is square; preferably, the side length of the square is 0.4-1 cm.

[0065] like Figure 3 As shown, the stirring paddle 4 is a cross-shaped stirring paddle with a wall scraper, and the edge of the stirring paddle is provided with a wall scraper soft brush 41; preferably, the stirring paddle is provided with a wall scraper soft brush made of polytetrafluoroethylene material.

[0066] The aeration flotation equipment further includes a motor 1, a scraper 2 and an overflow tank 3. The overflow tank 3 is arranged above the flotation reactor 10. The overflow tank 3 has an overflow tank discharge port N1. The aluminum foil is discharged from the overflow tank discharge port N1 through the overflow tank 3 along with the foam generated by flotation. The scraper 2 is arranged above the overflow tank 3. The scraper 2 can rotate. The rotating scraper can prevent the foam from overflowing the equipment. The motor 1 is connected to the stirring paddle 4 through a stirring rod to provide power for the stirring paddle.

[0067] The aeration flotation equipment further includes a reactor bottom cover 11, which is arranged below the flotation reactor and is used for discharging the lower layer of materials. The reactor bottom cover 11 is connected to the flotation reactor 10 through the bottom cover switch cylinder 9, and the reactor bottom cover 11 and the flotation reactor 10 are opened and closed by the extension and contraction of the bottom cover switch cylinder 9. The reactor bottom cover 11 is provided with a bottom discharge port N2 and an anti-blocking material jet port N5, and the anti-blocking material jet port N5 is arranged near the bottom discharge port N2.

[0068] The aeration flotation equipment further comprises a steam heating jacket 12 for passing steam to heat the kettle body. The steam heating jacket 12 has a jacket steam heating inlet N4 and a jacket steam heating outlet N3, wherein the jacket steam heating inlet N4 is arranged at the lower part of the steam heating jacket 12, and the jacket steam heating outlet N3 is arranged at the upper part of the steam heating jacket 12.

[0069] On the other hand, the present invention provides a method for efficiently stripping the positive electrode material and aluminum foil of scrapped lithium-ion batteries, using the above-mentioned aeration flotation equipment, such as Figure 4 and Figure 5 As shown, the following steps are included:

[0070] (1) Discharging and disassembling scrapped lithium-ion batteries to obtain positive electrode sheets, and then cutting the positive electrode sheets into square pieces, preferably, the side length of the square sheet is 3-10 cm, to obtain scrapped lithium-ion battery sheets;

[0071] (2) Aeration stripping: Put the scrapped lithium-ion battery pole piece material into the aeration flotation equipment, add a certain amount of stripping agent according to the solid content of 1-5%, preferably, the stripping agent is pure water, the pure water temperature is 40-90°C, then open the aeration valve to start aeration, and compressed air enters from the aeration right air inlet N7 and the aeration left air inlet N6 to achieve aeration, control the aeration gas flow rate to 20-50L / min, aerate for 10-20min, realize the stripping of the positive electrode material and the aluminum foil in the pole piece material, and then close the aeration valve;

[0072] (3) Flotation separation: The initial distance between the stirring paddle and the isolation net is adjusted to 3-6cm, and the speed of the stirring paddle is set to 10-100r / min. Stirring is started, and a foaming agent (dosing) is added; after stirring for 1-10 minutes, aeration is started, and the aeration gas flow rate is set to 10-40L / min; water is added during aeration, and the amount of water added is 0.5-2L / min. When the aluminum foil no longer floats, the distance between the stirring paddle and the isolation net is lowered to 0.5-2.5cm, and stirring and aeration are continued. After 10-40 minutes, the upper layer material is collected as aluminum foil, and the aluminum foil is discharged from the overflow tank discharge port N1 and enters the aluminum foil receiving bucket; the lower layer material is collected as positive electrode active material, and the positive electrode active material is discharged from the bottom discharge port N2 of the kettle, and filtered by the filter press to obtain active material black material; the solvent filtered out is supplemented with a foaming agent through the feeding bucket, and is recycled to the flotation reactor through the circulation system.

[0073] (4) The collected positive electrode active material is dried at 80-120° C. for 2-8 h in an inert atmosphere, then crushed to 200-800 mesh, and then the crushed material is calcined at 500-800° C. for 2-20 h in an inert atmosphere to obtain a positive electrode material repair material.

[0074] The present invention is further described in detail below through specific embodiments.

[0075] Examples 1 to 3

[0076] This embodiment provides an efficient stripping method for scrapped lithium-ion battery positive electrode material and aluminum foil, comprising the following steps:

[0077] (1) Discharging and disassembling scrapped lithium-ion batteries to obtain positive electrode sheet materials;

[0078] (2) Aeration stripping, prepare 400g of electrode material, the size of the electrode is 5*5cm 2 The apertures of the isolation nets are 0.4*0.4 / 0.6*0.6 / 0.9*0.9cm respectively. 2 , add pure water according to 2% solid content, put it into a 20L flotation reactor, set the temperature to 60℃, the aeration gas flow rate to 40L / min, and the aeration time to 20min.

[0079] (3) Flotation separation: adjust the distance between the stirring paddle and the isolation net to 4 cm, start stirring at a speed of 100 r / min, add a foaming agent, sodium dodecylbenzenesulfonate, at a dosage of 0.008% of the total mass of the slurry, stir for 5 minutes, start aeration, the aeration gas flow rate is 27 L / min, and add water (including foaming agent) at 1 L / min per minute. After aeration for 10 minutes, adjust the distance between the stirring paddle and the isolation net to 1 cm, and the stirring speed is 100 r / min. After stirring for 20 minutes, stop stirring and aeration, and collect the upper and lower layer materials respectively.

[0080] (4) The lower positive electrode active material is placed in a nitrogen atmosphere for drying and then crushed. The crushed black material is placed in a nitrogen atmosphere furnace for calcination (650° C., 3 h) to obtain a positive electrode material repair material.

[0081] Embodiments 4 to 7

[0082] This embodiment provides an efficient stripping method for scrapped lithium-ion battery positive electrode material and aluminum foil, comprising the following steps:

[0083] (1) Discharging and disassembling scrapped lithium-ion batteries to obtain positive electrode sheet materials;

[0084] (2) Aeration stripping, prepare 400g of electrode material, the sizes of the electrode pieces are 3*3 / 5*5 / 7*7 / 10*10cm respectively 2 , isolation mesh aperture 0.6*0.6cm 2 , add pure water according to 2% solid content, put it into a 20L flotation reactor, set the temperature to 60℃, the aeration gas flow rate to 40L / min, and the aeration time to 20min.

[0085] (3) Flotation separation: adjust the distance between the stirring paddle and the isolation net to 4 cm, start stirring at a speed of 100 r / min, add a foaming agent, sodium dodecylbenzenesulfonate, at a dosage of 0.008% of the total mass of the slurry, stir for 5 minutes, start aeration, the aeration gas flow rate is 27 L / min, and add water (including foaming agent) at 1 L / min per minute. After aeration for 10 minutes, adjust the distance between the stirring paddle and the isolation net to 1 cm, and the stirring speed is 100 r / min. After stirring for 20 minutes, stop stirring and aeration, and collect the upper and lower layer materials respectively.

[0086] (4) The lower positive electrode sheet is placed in a nitrogen atmosphere for drying, and then crushed. The crushed black material is placed in a nitrogen atmosphere furnace for calcination (650° C., 3 h) to obtain a positive electrode material repair material.

[0087] Embodiments 8 to 10

[0088] This embodiment provides an efficient stripping method for scrapped lithium-ion battery positive electrode material and aluminum foil, comprising the following steps:

[0089] (1) Discharging and disassembling scrapped lithium-ion batteries to obtain positive electrode sheet materials;

[0090] (2) Aeration stripping, prepare 400g of electrode material, the size of the electrode is 7*7cm 2 , isolation mesh aperture 0.6*0.6cm 2 , add pure water according to 2% solid content, put it into a 20L flotation reactor, set the temperature to 60℃, the aeration gas flow rate to 40L / min, and the aeration time to 20min.

[0091] (3) Flotation separation: adjust the distance between the stirring paddle and the isolation net to 4 cm, start stirring at a speed of 100 r / min, add a foaming agent, sodium dodecylbenzenesulfonate, at a dosage of 0.008% of the total mass of the slurry, stir for 5 minutes, start aeration, the aeration gas flow rate is 27 L / min, and add water (including foaming agent) at 1 L / min per minute. After aeration for 10 minutes, adjust the distance between the stirring paddle and the isolation net to 2 / 1 / 0 cm, respectively, and stir at a speed of 100 r / min. After stirring for 20 minutes, stop stirring and aeration, and collect the upper and lower layer materials respectively.

[0092] (4) The lower positive electrode sheet is placed in a nitrogen atmosphere for drying, and then crushed. The crushed black material is placed in a nitrogen atmosphere furnace for calcination (650° C., 3 h) to obtain a positive electrode material repair material.

[0093] Examples 11 to 13

[0094] This embodiment provides an efficient stripping method for scrapped lithium-ion battery positive electrode material and aluminum foil, comprising the following steps:

[0095] (1) Discharging and disassembling scrapped lithium-ion batteries to obtain positive electrode sheet materials;

[0096] (2) Aeration stripping, prepare 400 / 600 / 800g of electrode material respectively, the size of the electrode is 7*7cm 2 , isolation mesh aperture 0.6*0.6cm 2 , pure water was added at 2% / 3% / 4% solid content respectively, and placed in a 20L flotation reactor. The temperature was set to 60°C, the aeration gas flow rate was 40L / min, and the aeration time was 20min.

[0097] (3) Flotation separation: adjust the distance between the stirring paddle and the isolation net to 4 cm, start stirring at a speed of 100 r / min, add a foaming agent, sodium dodecylbenzenesulfonate, at a dosage of 0.008% of the total mass of the slurry, stir for 5 minutes, start aeration, the aeration gas flow rate is 27 L / min, and water (including foaming agent) is added at 1 L / min per minute. After aeration for 10 minutes, adjust the distance between the stirring paddle and the isolation net to 1 cm, and the stirring speed is 100 r / min. After stirring for 20 minutes, stop stirring and aeration, and collect the upper and lower layer materials respectively.

[0098] (4) The lower positive electrode sheet is placed in a nitrogen atmosphere for drying, and then crushed. The crushed black material is placed in a nitrogen atmosphere furnace for calcination (650° C., 3 h) to obtain a positive electrode material repair material.

[0099] Comparative Example 1

[0100] The difference from Example 1 is that the aeration flotation equipment does not include an isolation net, and the remaining equipment structures and experimental steps are the same as those in Example 1.

[0101] Comparative Example 2

[0102] The difference from Example 1 is that the stirring paddle does not include a soft brush for scraping the wall, and the rest of the equipment structure and experimental steps are the same as those of Example 1.

[0103] The black material products obtained in the above examples and comparative examples were tested, the aluminum content in the black material was tested, and the aluminum yield and black material yield were tested. The results are shown in Table 1:

[0104] Table 1

[0105]

[0106]

[0107] As can be seen from Table 1, the aluminum yield, black material yield, and aluminum content in the black material in the product obtained in Example 12 are the best. In Comparative Example 1, no isolation net is used, which causes the aluminum foil to easily leak during the flotation process, and the aluminum content of the black material is high. In Comparative Example 2, no wall scraping soft brush is used, which causes part of the electrode sheet and the aluminum foil to easily stick to the wall during the stirring process, and cannot be separated and collected normally.

[0108] The specific embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0109] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0110] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. An efficient stripping method for scrapped lithium-ion battery positive electrode materials and aluminum foil, characterized in that: The following steps are involved: Aeration stripping: Put the scrapped lithium-ion battery pole pieces into the aeration flotation equipment, add a certain amount of stripping agent, open the aeration valve to start aeration, realize the stripping of the positive electrode material and the aluminum foil in the pole piece, and then close the aeration valve; Flotation separation: After adjusting the distance between the stirring paddle and the isolation net, start stirring, add a frother, and start aeration after stirring for a certain period of time. When the aluminum foil no longer floats, lower the distance between the stirring paddle and the isolation net, continue stirring and aerating, collect the upper material as aluminum foil, and collect the lower material as positive electrode active material; The aeration flotation equipment comprises an air flotation reactor, an agitator, an aeration plate and an isolation net. The isolation net is arranged on the aeration plate and together with the aeration plate, the agitator is arranged inside the air flotation reactor. The distance between the agitator and the isolation net can be adjusted.

2. The method according to claim 1, characterized in that The preparation process of the scrapped lithium-ion battery electrode sheet material comprises: discharging and disassembling the scrapped lithium-ion battery to obtain a positive electrode sheet material, and then cutting the positive electrode sheet material into square sizes; Preferably, the side length of the square pole sheet is 3-10 cm.

3. The method according to claim 1, characterized in that: The stripping agent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, water, and oxalic acid; Preferably, the stripping agent is added in an amount such that the solid content of the slurry is 1-5%; Preferably, the temperature of the stripping agent is 40-90°C.

4. The method according to claim 1, characterized in that: In the aeration stripping step, the aeration gas flow rate of the aeration flotation equipment is 20-50 L / min; Preferably, the mesh of the isolation net in the aeration flotation device is square, and the side length of the square is 0.4-1 cm.

5. The method according to claim 1, characterized in that In the flotation separation step, the initial distance between the stirring paddle and the isolation net is 3-6 cm, and the rotation speed of the stirring paddle is 10-100 r / min.

6. The method according to claim 1, characterized in that When the aluminum foil no longer floats, the distance between the stirring paddle and the isolation net is lowered to 0.5-2.5 cm. At the same time, the rotation speed of the stirring paddle is 10-100 r / min, and the aeration gas flow rate is 10-40 L / min.

7. The method according to claim 1, characterized in that The foaming agent is one or more of sodium dodecylbenzenesulfonate and sodium dodecanesulfonate; Preferably, the amount of the foaming agent added is 0.002-0.02% of the mass of the stripping agent.

8. An aeration flotation device, characterized in that: The invention comprises an air flotation reactor, a stirring paddle, an aeration plate and an isolation net. The isolation net is arranged on the aeration plate and is arranged together at the bottom of the air flotation reactor. The stirring paddle is arranged inside the air flotation reactor. The distance between the stirring paddle and the isolation net can be adjusted.

9. The device according to claim 8, characterized in that The aeration plate is made of a nano-microporous aeration tube, which is fastened to a fixing frame with a fixing buckle to make an aeration plate, and the aeration tube is connected to the aeration right air inlet and the aeration left air inlet to achieve aeration; Preferably, the stirring paddle is a cross-shaped stirring paddle with a wall scraper, and a soft wall scraper brush is attached to the edge of the stirring paddle.

10. The device according to claim 8, characterized in that The aeration flotation equipment also includes a motor, a scraper and an overflow tank; The overflow tank is arranged above the air flotation reactor, and the overflow tank is provided with an overflow tank discharge port; the scraper is arranged above the overflow tank, and the scraper can rotate, and the rotating scraper can prevent the foam from overflowing the equipment.

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