Separation equipment and process for positive plates of waste lithium batteries

Abstract

The invention discloses separation equipment and process for a positive plate of a waste lithium battery. The separation equipment comprises a shredding device, a pyrolysis device, a powder removal device and a screening device which are communicated in sequence; the shredding device is used for shredding the positive plates of the waste lithium batteries; the pyrolysis device is used for pyrolyzing the shredded waste lithium battery to remove an electrolyte and a binder; the powder removing device is used for dissociating the pyrolyzed positive plate; and the screening device is used for separating powder products of the powder removing device. According to the separation process disclosed by the invention, the residual electrolyte in the positive plate of the waste lithium battery made of various different positive electrode materials can be effectively removed at a low temperature in a superheated acid mist-gradient pyrolysis synergistic manner, and the viscosity of a binder and the content of aluminum impurities in the black powder are reduced.

Description

Technical Field

[0001] This invention relates to the field of environmental protection technology, and in particular to a separation device and process for waste lithium battery positive electrode sheets. Background Technology

[0002] With the rapid development of electric vehicles and portable electronic devices globally, the production and use of lithium-ion batteries have increased dramatically, leading to a rapid rise in the number of discarded lithium-ion batteries. Discarded lithium-ion batteries contain large amounts of valuable metals (such as lithium, cobalt, and nickel) and other valuable materials. If not properly recycled, they will not only cause serious waste of resources but also pose potential pollution risks to the environment, as heavy metals and harmful substances may seep into soil and water bodies, harming ecosystems and human health.

[0003] The positive electrode sheet of a spent lithium-ion battery is a sandwich-structured material, consisting of positive electrode black powder, aluminum foil, and binders. Types of binders include polyacrylic acid (PAA), polymethyl methacrylate (PMMA), and polyvinylidene fluoride (PVDF). Electrode interface dissociation technology is a crucial step in the recycling of spent lithium-ion batteries, primarily encompassing mechanical, pyrolysis, and chemical methods. Mechanical methods break down the electrode interface through physical means such as cutting and grinding; this process is simple and low-cost, but may damage the active material structure and has limited separation efficiency. Pyrolysis decomposes the binder in a high-temperature, inert gas atmosphere to achieve separation; it is effective for specific electrodes but consumes a lot of energy and may cause chemical changes in the active material. Chemical methods utilize chemical reagents to react with the electrode components, achieving excellent separation, but presenting environmental pollution and material corrosion issues. Future development of this technology will focus on combined processes, green environmental protection, and intelligent control to improve separation efficiency and quality, reduce costs, meet environmental requirements, and achieve sustainable development in the recycling of spent lithium-ion batteries.

[0004] Current processing methods are cumbersome, resulting in low-quality black powder and aluminum particles. Most existing methods target oil-based PVDF (polyvinylidene fluoride) binders and do not consider positive electrode sheets using water-based binders such as PAA (polyacrylic acid) and PMMA (polymethyl methacrylate). Therefore, developing a highly efficient, environmentally friendly, low-cost, and universally applicable technology for separating waste lithium-ion battery positive electrode sheets is of significant practical importance. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a separation device for waste lithium battery positive electrode sheets. This separation device can improve the electrode interface dissociation efficiency and reduce the aluminum impurity content in the black powder.

[0006] The further technical problem to be solved by the present invention is to provide a separation process for waste lithium battery positive electrode sheets.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A separation device for waste lithium battery positive electrode sheets includes a shredding device, a pyrolysis device, a powder removal device, and a screening device connected in sequence. The shredding device is used to shred the waste lithium battery positive electrode sheets. The pyrolysis device is used to pyrolyze the shredded waste lithium batteries to remove electrolyte and reduce binder viscosity. The powder removal device is used to dissociate the positive electrode sheets after pyrolysis. The screening device is used to separate the powder products from the powder removal device, and the separated products are aluminum current collectors and black powder.

[0009] The pyrolysis device includes a pyrolysis furnace, which is provided with a feed inlet, an air inlet and a discharge outlet. The feed inlet is connected to the shredding device, and the discharge outlet is connected to the powder removal device. The air inlet is used to introduce a protective gas, which is an inert gas such as nitrogen or argon.

[0010] The pyrolysis furnace is also equipped with an acid mist inlet, which is connected to the superheated acid mist generator.

[0011] The powder removal device includes several rotating shafts arranged in parallel, and rubber rods are mounted on the rotating shafts in an alternating pattern.

[0012] Each rotating shaft of the powder removal device is equipped with an independent drive system, and the rotation speed and direction of rotation of the rotating shafts are different.

[0013] The pyrolysis furnace is also equipped with an anti-backflow device.

[0014] The waste lithium battery positive electrode sheet separation equipment also includes a tail gas treatment device, which comprises a condenser, a cyclone dust collector, a combustion chamber, a heat exchanger, a bag filter, an alkaline spray tower, a wire mesh demister, an activated carbon adsorber, and an induced draft fan connected in sequence. The condenser condenses water vapor mixed in with the pyrolysis tail gas to obtain pretreated tail gas; the combustion chamber burns the pretreated tail gas; the heat exchanger cools the pretreated tail gas after combustion; the bag filter removes dust from the tail gas after heat exchange; the alkaline spray tower removes acidic pollutants from the tail gas; the wire mesh demister removes liquid droplets entrained in the tail gas; the activated carbon adsorber adsorbs residual pollutants in the tail gas; and the induced draft fan is connected to the activated carbon adsorber to provide power to the entire tail gas treatment device.

[0015] The alkaline spray tower includes a primary alkaline spray tower and a secondary alkaline spray tower, and the exhaust gas passes through the primary alkaline spray tower and the secondary alkaline spray tower in sequence.

[0016] A separation process for waste lithium battery positive electrode sheets, which uses the aforementioned waste lithium battery positive electrode sheet separation equipment, includes the following steps:

[0017] S1: Shredded positive electrode sheets are obtained by shredding waste lithium battery positive electrode sheets using a shredding device;

[0018] S2: The shredded positive electrode sheet is subjected to gradient pyrolysis using a pyrolysis device to obtain pyrolytic positive electrode fragments;

[0019] S3: The pyrolytic cathode fragments are processed using a de-powdering device to obtain pyrolytic powder;

[0020] S4: The pyrolysis powder is sieved using a sieving device to obtain aluminum current collector and black powder;

[0021] The gradient pyrolysis process specifically includes the following steps:

[0022] S21: Treat the shredded positive electrode sheet at 100-150℃ for 0.5-1h;

[0023] S22: Then raise the temperature to 100-250℃, and then introduce superheated acid mist vapor at 100-250℃ for 0.5-2 hours.

[0024] In step S3, the rotation directions of two adjacent pairs of rotating shafts in the descaling device are opposite, and the rotation speed of the rotating shafts increases in a gradient according to the order of contact with the pyrolytic cathode fragments.

[0025] The flow rate of the superheated acid mist vapor is 1~3 kg / t, and the volume percentage of acid vapor in the superheated acid mist vapor is greater than 0 and less than or equal to 1 vol.%.

[0026] The separation process further includes the step of treating the exhaust gas using an exhaust gas treatment device.

[0027] The beneficial effects of this invention are as follows:

[0028] (1) The separation process of the present invention can effectively remove residual electrolyte, reduce adhesive viscosity and aluminum impurity content in waste lithium battery cathode sheets of various cathode materials at low temperature by superheated acid mist-gradient pyrolysis synergistic method.

[0029] (2) The de-powdering device in the separation equipment of the present invention can significantly improve the dissociation rate of the positive electrode black powder and prevent the aluminum current collector from being excessively crushed and entering the black powder to form impurities.

[0030] (3) The exhaust gas treatment device of the present invention treats exhaust gas in all aspects, from gas-liquid separation, dust removal, oxidative decomposition of harmful gases, heat recovery, absorption of acidic pollutants to adsorption of volatile organic compounds, ensuring that pollutant emissions meet environmental protection standards and minimizing exhaust gas pollution. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure of the waste lithium battery positive electrode sheet separation device of the present invention.

[0032] Figure 2 This is a schematic diagram of the overall structure of the pyrolysis device in the waste lithium battery cathode sheet separation equipment of the present invention.

[0033] Figure 3 This is a schematic diagram of the overall structure of the de-powdering device in the waste lithium battery positive electrode separation equipment of the present invention.

[0034] Figure 4 This is a side view of the powder removal device in the waste lithium battery cathode sheet separation equipment of the present invention.

[0035] Figure 5 This is a schematic diagram of the overall structure of the exhaust gas treatment device in the waste lithium battery positive electrode sheet separation equipment of the present invention.

[0036] Figure 6 This is a schematic diagram of the separation process for the positive electrode sheet of a waste lithium battery according to the present invention.

[0037] The attached figures are labeled as follows:

[0038] 1- Shredding device; 101- Shredding outlet; 102- Conveyor belt; 2- Pyrolysis device; 21- Superheated acid mist generator; 22- Pyrolysis furnace; 23- Anti-backflow device; 221- Feed inlet; 222- Air inlet; 223- Pyrolysis furnace outlet; 224- Acid mist inlet; 225- Air outlet; 3- Powder removal device; 31- First pair of rotating shafts; 32- Second pair of rotating shafts; 33- Third pair of rotating shafts; 34- Rubber rod; 4- Screening device; 5- Black powder; 6- Aluminum current collector; 7- Condenser; 8- Cyclone dust collector; 9- Combustion chamber; 10- Heat exchanger; 11- Baghouse dust collector; 12- Primary alkali spray tower; 13- Secondary alkali spray tower; 14- Wire mesh demister; 15- Activated carbon adsorber; 16- Exhaust fan. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0040] See Figure 1 This invention provides a separation device for waste lithium battery positive electrode sheets, comprising a shredding device 1, a pyrolysis device 2, a powder removal device 3, and a screening device 4 connected in sequence; the shredding device 1 is used to shred the waste lithium battery positive electrode sheets; the pyrolysis device 2 is used to pyrolyze the shredded waste lithium battery positive electrode sheets to remove electrolyte and binder; the powder removal device 3 is used to dissociate the positive electrode sheets after pyrolysis; the screening device 4 is used to separate the powder products from the powder removal device 3, the separated products being aluminum current collector 6 and black powder 5.

[0041] Specifically, the purpose of the shredding device 1 is to perform primary crushing of waste lithium battery positive electrode sheets, achieving preliminary separation of materials to facilitate subsequent pyrolysis processing. The shredding outlet 101 below the shredding device 1 is connected to the lower part of the conveyor belt 102, and the upper part of the conveyor belt 102 is connected to the feed inlet 221 of the pyrolysis furnace 22 of the pyrolysis device 2. The conveyor belt 102 evenly transports the pre-crushed electrode sheets into the pyrolysis furnace 22. The shredding device 1 in this invention is a shredder.

[0042] The purpose of pyrolysis device 2 is to pyrolyze the pre-shredded waste lithium battery positive electrode sheets. Pyrolysis device 2 uses gradient pyrolysis and superheated acid mist vapor-assisted pyrolysis to remove electrolyte and reduce binder viscosity, respectively.

[0043] Among them, see Figure 2 The pyrolysis device 2 includes a pyrolysis furnace 22, which is provided with a feed inlet 221, an air inlet 222 and a pyrolysis furnace outlet 223. The feed inlet 221 is connected to the shredding device 1, the pyrolysis furnace outlet 223 is connected to the powder removal device 3, and the air inlet 222 is used to introduce protective gas.

[0044] Further, see Figure 2 The pyrolysis furnace 22 is also equipped with an acid mist inlet 224, which is connected to the superheated acid mist generator 21. Additionally, the pyrolysis furnace 22 is also equipped with an anti-backflow device 23.

[0045] The powder removal device 3 is connected to the pyrolysis furnace outlet 223 of the pyrolysis furnace 22, and its function is to separate the electrode sheets processed by the pyrolysis furnace 22. (See also...) Figure 3The de-powdering device 3 includes several pairs of rotating shafts (a horizontally arranged pair of rotating shafts), which are arranged longitudinally. Each rotating shaft is equipped with multiple rubber rods 34, which are arranged in an alternating pattern. The rubber rods 34, arranged in an array, flexibly crush the electrode sheet, preventing the aluminum foil from being over-pulverized, thus facilitating subsequent sieving and reducing the aluminum content in the black powder 5.

[0046] For details, see Figure 3 and Figure 4 The powder removal device 3 is equipped with a first pair of rotating shafts 31, a second pair of rotating shafts 32, and a third pair of rotating shafts 33, which are arranged longitudinally and in parallel. Each pair of rotating shafts includes two rotating shafts, which are also arranged in parallel and opposite directions. The rubber rods 34 of each pair of rotating shafts are intersected and contact each other during rotation.

[0047] More preferably, each pair of rotating shafts in the de-powdering device 3 is equipped with an independent drive system, and the rotation speed and direction of rotation of the several rotating shafts are different. Preferably, among the several pairs of rotating shafts, the directions of rotation of adjacent pairs of rotating shafts are opposite (e.g., clockwise-counterclockwise-clockwise; or counterclockwise-clockwise-counterclockwise-clockwise); and the rotation speed is set in a gradient increasing manner, that is, the rotation speed increases with the order of contact with the electrode sheet after de-furnace treatment, such as rotation speeds of 200, 220, and 250 r / min respectively. This setting can enhance material disturbance, efficiently dissociate black powder 5 and reduce aluminum impurity content.

[0048] In this embodiment, the core internal structure of the de-powdering device 3 consists of three sets of parallel rotating shafts. Each of these three sets of rotating shafts has an independent drive system, enabling them to operate at specific and different speeds, and their rotation directions also differ. This unique speed and direction setting allows the de-powdering device 3 to create an extremely complex and efficient material interaction environment during operation. Each rotating shaft is tightly fitted with a large number of rubber rods 34, which are arranged in an alternating pattern on the shaft. When the shaft rotates at high speed, this greatly increases the contact area and contact points between the rubber rods 34 and the pyrolysis cathode fragments. On the one hand, it can efficiently dissociate the black powder 5 attached to the pyrolytic positive electrode fragments, significantly improving the dissociation rate of the positive electrode black powder 5; on the other hand, during the dissociation process of the black powder 5, due to the staggered arrangement of the rubber rods 34 and the different rotation speeds and directions of the shafts, the black powder 5 can move fully in the complex flow field environment inside the powder removal device 3 after being separated from the pyrolytic positive electrode fragments, reducing the probability of the black powder 5 re-contacting and mixing with aluminum impurities, thereby effectively reducing the aluminum impurity content in the black powder 5.

[0049] The screening device 4 is connected to the discharge port of the de-powdering device 3, and its purpose is to screen the aluminum current collector 6 and black powder 5 separated by the de-powdering device 3. In this embodiment, the screening device 4 is a vibrating screen.

[0050] See Figure 1 and Figure 5 The equipment for separating waste lithium battery positive electrode sheets also includes a tail gas treatment device. The purpose of the tail gas treatment device is to reduce the emission of pollutants in the tail gas to protect the environment and human health. The main equipment includes a condenser 7, a cyclone dust collector 8, a combustion chamber 9, a heat exchanger 10, a bag dust collector 11, an alkaline spray tower, a wire mesh demister 14, an activated carbon adsorber 15, and an induced draft fan 16 connected in sequence. Condenser 7 is connected to the outlet 225 of pyrolysis furnace 22. It is used to condense acid mist mixed in the pyrolysis tail gas, realize gas-liquid separation, reduce tail gas temperature, and avoid excessive acid mist and water vapor from adversely affecting subsequent equipment. Cyclone dust collector 8 is connected to condenser 7. Its function is to use centrifugal force to separate dust particles in the tail gas from the airflow and remove larger dust particles in the tail gas. Combustion chamber 9 is connected to cyclone dust collector 8. It combusts the pretreated tail gas, causing the combustible pollutants in the tail gas to undergo oxidation reaction at high temperature, converting them into harmless substances such as carbon dioxide and water, thereby reducing the emission of harmful gases. Heat exchanger 10 is connected to combustion chamber 9. It recovers heat from the tail gas through heat exchange and cools the flue gas after pyrolysis. Bag filter 11 is connected to heat exchanger 10. It uses the filtration effect of the filter bags to further remove finer dust particles in the tail gas. The system removes particulate matter, ensuring that the dust content in the exhaust gas meets stricter emission standards and reduces dust pollution to the environment. An alkaline spray tower connected to a bag filter 11 removes acidic pollutants from the pyrolysis flue gas, purifying the exhaust gas. A wire mesh demister 14 connected to the alkaline spray tower removes droplets entrained in the exhaust gas, preventing them from entering subsequent equipment and causing corrosion or blockages, while also improving the cleanliness of the exhaust gas. An activated carbon adsorber 15 connected to the wire mesh demister 14 uses the adsorption properties of activated carbon to adsorb residual volatile organic compounds and other pollutants that are difficult to remove completely by other methods, further purifying the exhaust gas. An induced draft fan 16 connected to the activated carbon adsorber 15 provides power to the entire exhaust gas treatment system, allowing the exhaust gas to flow smoothly between various devices and ensuring the continuity and stability of the exhaust gas treatment process.

[0051] For an even better option, see [link to previous section]. Figure 5The alkaline spray tower includes a primary alkaline spray tower 12 and a secondary alkaline spray tower 13. The exhaust gas passes through the primary alkaline spray tower 12 and the secondary alkaline spray tower 13 sequentially. The primary alkaline spray tower 12 is connected to a bag filter 11 and is used to remove the concentration of acidic pollutants in the pyrolysis flue gas, thereby purifying the exhaust gas. The secondary alkaline spray tower 13 is connected to the primary alkaline spray tower 12 and performs a second spray treatment on the exhaust gas after it has been treated by the primary alkaline spray tower 12. Calcium hydroxide solution is used for a secondary spray treatment of the flue gas, further improving the removal effect of acidic pollutants such as fluorine and phosphorus in the exhaust gas and ensuring more thorough removal of pollutants. A wire mesh demister 14 is connected to the secondary alkaline spray tower 13.

[0052] Accordingly, see Figure 6 The present invention also provides a separation process for waste lithium battery positive electrode sheets, which uses the above-mentioned separation equipment for waste lithium battery positive electrode sheets, and the separation process includes the following steps:

[0053] S1: Use shredding device 1 to shred waste lithium battery positive electrode sheets to obtain small-sized positive electrode sheets;

[0054] S2: The small-sized positive electrode sheet is pyrolyzed using pyrolysis device 2 to obtain pyrolytic positive electrode fragments;

[0055] S3: The pyrolytic cathode fragments are processed by the de-powdering device 3 to obtain pyrolytic powder;

[0056] S4: The pyrolysis powder is sieved using a sieving device 4 to obtain aluminum current collector 6 and black powder 5.

[0057] Furthermore, the pyrolysis treatment is a gradient pyrolysis treatment, which specifically includes:

[0058] S21: The shredded positive electrode sheet is treated at 100-150℃ for a certain period of time to allow the electrolyte to evaporate for 0.5-1h;

[0059] S22: Then raise the temperature to 100-250℃ and pass in superheated acid mist vapor at 100-250℃ for 0.5-2 hours to reduce the adhesion of the bonding interface.

[0060] Ideally, the inert atmosphere within the pyrolysis furnace 22 should be controlled during both processes to prevent electrode oxidation. Specifically, the positive electrode material composition of the waste lithium battery can be lithium iron phosphate, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, or lithium nickel cobalt manganese oxide; the electrode binder can be any of the binders such as polyacrylic acid (PAA), polymethyl methacrylate (PMMA), or polyvinylidene fluoride (PVDF); the superheated acid mist vapor is generated by a steam generator, and its acidic liquid component can be one or more of inorganic acids such as nitric acid, sulfuric acid, and hydrochloric acid, or organic acids such as formic acid and oxalic acid, wherein the volume percentage of acid vapor in the superheated acid mist vapor is greater than 0 and less than or equal to 1 vol.%; the protective atmosphere can be one or more of nitrogen, argon, or helium.

[0061] The main operation of the pyrolysis treatment is as follows: After the shredded electrode sheets enter the pyrolysis furnace 22, inert gas is first introduced to purge the furnace and remove the air inside. Then, gradient pyrolysis is used to heat-treat the electrode sheets. Residual electrolyte is removed at a low temperature of 100-150℃, and the adhesion of the bonding interface is reduced under the condition of 100-250℃ combined with isothermal superheated acid mist vapor pyrolysis. The amount of superheated acid mist vapor can be adjusted according to the amount of material. The outlet of the superheated acid mist generator 21 is connected to the acid mist inlet 224 of the pyrolysis furnace 22, and the outlet 225 of the pyrolysis furnace 22 is connected to the inlet of the tail gas treatment system.

[0062] Preferably, the separation process further includes the step of treating the exhaust gas using an exhaust gas treatment device.

[0063] Example 1

[0064] A separation process for waste lithium battery cathode sheets (the cathode system is LFP-PAA, i.e., lithium iron phosphate battery, and the binder is PAA) includes the following steps:

[0065] (1) Put the waste lithium battery positive electrode sheet into the shredder, shred it and then put it into the pyrolysis furnace 22.

[0066] (2) Inert gas is introduced to purge the pyrolysis furnace 22, and the electrolyte is removed by pyrolysis at 120°C for 30 minutes.

[0067] (3) Start the pyrolysis furnace 22, heat it to 180°C and then introduce superheated acid mist vapor (the volume percentage of acid vapor in the superheated acid mist vapor is 1 vol.%), maintain for 60 min, and use the residual heat of the pyrolysis furnace 22 to dry the electrode sheet after pyrolysis.

[0068] (4) The electrode sheets after pyrolysis and drying enter the powder removal device 3. The rotation speeds of the three shafts are set to 200 r / min, 220 r / min and 250 r / min respectively, and the rotation directions are counterclockwise, clockwise and counterclockwise. The powder removal process lasts for 10 min.

[0069] (5) The pyrolysis tail gas passes through the condenser 7, cyclone dust collector 8, combustion chamber 9, heat exchanger 10, bag dust collector 11, primary alkaline spray tower 12, secondary alkaline spray tower 13, wire mesh demister 14, and activated carbon adsorber 15 in sequence, and is then discharged by the induced draft fan 16 after meeting the emission standards.

[0070] In this embodiment, the material dissociation rate is 98.5%, and the aluminum impurity content in black powder 5 is 0.1%.

[0071] Example 2

[0072] A separation process for waste lithium battery cathode sheets (the cathode system is NCM523-PVDF, i.e., nickel-cobalt-manganese lithium oxide battery, and the binder is PVDF) includes the following steps:

[0073] (1) Put the waste lithium battery positive electrode sheet into the shredder, shred it and then put it into the pyrolysis furnace 22.

[0074] (2) Inert gas is introduced to purge the pyrolysis furnace 22, and the electrolyte is removed by pyrolysis at 130°C for 45 minutes.

[0075] (3) Start the pyrolysis furnace 22, heat it to 200°C and then introduce superheated acid mist vapor (the volume percentage of acid vapor in the superheated acid mist vapor is 0.5 vol.%), maintain for 90 min, and use the residual heat of the pyrolysis furnace 22 to dry the electrode after pyrolysis.

[0076] (4) The electrode sheets after pyrolysis and drying enter the powder removal device 3. The rotation speeds of the three shafts are set to 220 r / min, 250 r / min and 270 r / min respectively, and the rotation directions are counterclockwise, clockwise and counterclockwise. The powder removal process lasts for 20 min.

[0077] (5) The pyrolysis tail gas passes through the condenser 7, cyclone dust collector 8, combustion chamber 9, heat exchanger 10, bag dust collector 11, primary alkaline spray tower 12, secondary alkaline spray tower 13, wire mesh demister 14, and activated carbon adsorber 15 in sequence, and is then discharged by the induced draft fan 16 after meeting the emission standards.

[0078] In this embodiment, the material dissociation rate is 99%, and the aluminum impurity content in black powder 5 is 0.08%.

[0079] Example 3

[0080] A separation process for waste lithium battery cathode sheets (the cathode system is NCA-PVDF, i.e., ternary polymer lithium battery, and the binder is PVDF) includes the following steps:

[0081] (1) Put the waste lithium battery positive electrode sheet into the shredder, shred it and then put it into the pyrolysis furnace 22.

[0082] (2) Inert gas is introduced to purge the pyrolysis furnace 22, and the electrolyte is removed by pyrolysis at 140°C for 60 min.

[0083] (3) Start the pyrolysis furnace 22, heat it to 220°C and then introduce superheated acid mist vapor (the volume percentage of acid vapor in the superheated acid mist vapor is 0.3 vol.%), maintain for 120 min, and use the residual heat of the pyrolysis furnace 22 to dry the electrode after pyrolysis.

[0084] (4) The electrode sheets after pyrolysis and drying enter the powder removal device 3. The rotation speeds of the three shafts are set to 200 r / min, 220 r / min and 250 r / min respectively, and the rotation directions are counterclockwise, clockwise and counterclockwise. The powder removal process lasts for 30 minutes.

[0085] (5) The pyrolysis tail gas passes through the condenser 7, cyclone dust collector 8, combustion chamber 9, heat exchanger 10, bag dust collector 11, primary alkaline spray tower 12, secondary alkaline spray tower 13, wire mesh demister 14, and activated carbon adsorber 15 in sequence, and is then discharged by the induced draft fan 16 after meeting the emission standards.

[0086] In this embodiment, the material dissociation rate is 98.8%, and the aluminum impurity content in black powder 5 is 0.12%.

[0087] Example 4

[0088] A separation process for waste lithium battery cathode sheets (the cathode system is LCO-PVDF, i.e., lithium cobalt oxide battery, and the binder is PVDF) includes the following steps:

[0089] (1) Put the waste lithium battery positive electrode sheet into the shredder, shred it and then put it into the pyrolysis furnace 22.

[0090] (2) Purge the pyrolysis furnace 22 with inert gas and pyrolyze at 110°C for 30 min to remove the electrolyte.

[0091] (3) Start the pyrolysis furnace 22, heat it to 160°C and then introduce superheated acid mist vapor (the volume percentage of acid vapor in the superheated acid mist vapor is 0.5 vol.%), maintain for 60 min, and use the residual heat of the pyrolysis furnace 22 to dry the electrode after pyrolysis.

[0092] (4) The electrode sheets after pyrolysis and drying enter the powder removal device 3. The rotation speeds of the three shafts are set to 200 r / min, 220 r / min and 250 r / min respectively, and the rotation directions are counterclockwise, clockwise and counterclockwise. The powder removal process lasts for 10 min.

[0093] (5) The pyrolysis tail gas passes through the condenser 7, cyclone dust collector 8, combustion chamber 9, heat exchanger 10, bag dust collector 11, primary alkaline spray tower 12, secondary alkaline spray tower 13, wire mesh demister 14, and activated carbon adsorber 15 in sequence, and is then discharged by the induced draft fan 16 after meeting the emission standards.

[0094] In this embodiment, the material dissociation rate is 97.8%, and the aluminum impurity content in black powder 5 is 0.2%.

[0095] The experimental procedures for other embodiments are the same as those for Embodiment 1, and the experimental results are shown in Table 1.

[0096] Table 1 Experimental Data

[0097]

[0098] As can be seen from the experimental results in Table 1, the separation process of the present invention reduces the separation temperature of the electrode, and a high separation effect can be achieved within the temperature range of 100-250℃.

[0099] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0100] The parts of this invention not described in detail are well-known in the art. The above embodiments are provided merely for the purpose of describing the invention and are not intended to limit its scope. The scope of the invention is defined by the appended claims. All equivalent substitutions and modifications made without departing from the spirit and principles of the invention should be covered within its scope.

Claims

1. A separation apparatus of a positive electrode sheet of a waste lithium battery, characterized by, The separation equipment comprises, in sequence, a shredding device, a pyrolysis device, a powder removing device and a screening device; the shredding device is used for shredding the positive plate of the waste lithium battery; the pyrolysis device is used for pyrolyzing the shredded positive plate to remove electrolyte and reduce the viscosity of the binder; the powder removing device is used for dissociating the positive plate after pyrolysis; and the screening device is used for separating the powder product of the powder removing device. The pyrolysis device comprises a pyrolysis furnace, and the pyrolysis furnace is provided with a feeding port, an air inlet and a discharging port; the feeding port is communicated with the shredding device; the discharging port is communicated with the powder removing device; and the air inlet is used for introducing a protective gas; the pyrolysis furnace is further provided with an acid mist air inlet, and the acid mist air inlet is communicated with the superheated acid mist generator.

2. The separation apparatus of the old lithium battery cathode sheet according to claim 1, characterized by, The powder removing device comprises a plurality of rotating shafts, the rotating shafts are arranged in parallel, and rubber rods are arranged on the rotating shafts.

3. The separating apparatus of the positive electrode sheet of the waste lithium battery according to claim 2, characterized in that, Each rotating shaft of the powder removing device is provided with an independent driving system, and the rotating speeds and rotating directions of the rotating shafts are different.

4. The separation apparatus of the old lithium battery cathode sheet according to claim 1, characterized by, The pyrolysis furnace is further provided with an anti-backflow device.

5. The separation apparatus of the positive electrode sheet of the waste lithium battery according to any one of claims 1 to 4, characterized by The separation equipment for the positive plate of the waste lithium battery further comprises a tail gas treatment device, and the tail gas treatment device comprises, in sequence, a condenser, a cyclone dust collector, a combustion chamber, a heat exchanger, a bag-type dust collector, an alkali liquor spraying tower, a wire mesh mist eliminator, an activated carbon adsorber and an induced draft fan; the condenser is used for condensing acid mist water vapor doped in the pyrolysis tail gas to obtain pretreated tail gas; the combustion chamber is used for burning the pretreated tail gas; the heat exchanger is used for cooling the pretreated tail gas after combustion; the bag-type dust collector is used for removing dust in the tail gas after heat exchange; and the alkali liquor spraying tower is used for removing acidic pollutants in the tail gas. The wire mesh mist eliminator is used for removing liquid droplets entrained in the tail gas, the activated carbon adsorber is used for adsorbing residual pollutants in the tail gas, and the induced draft fan is connected with the activated carbon adsorber and is used for providing power for the entire tail gas treatment device.

6. The apparatus according to claim 5, wherein the apparatus further comprises a separator for separating the positive electrode tab from the negative electrode tab. The alkali liquor spraying tower comprises a primary alkali liquor spraying tower and a secondary alkali liquor spraying tower, and the tail gas passes through the primary alkali liquor spraying tower and the secondary alkali liquor spraying tower in sequence.

7. A separation process of a positive electrode sheet of a waste lithium battery, characterized by, The separation process comprises the following steps by using the separation equipment for the positive plate of the waste lithium battery according to any one of claims 1 to 6: S1: shredding the positive plate of the waste lithium battery by using the shredding device to obtain shredded positive plate; S2: gradient pyrolyzing the shredded positive plate by using the pyrolysis device to obtain pyrolyzed positive fragments; S3: processing the pyrolyzed positive fragments by using the powder removing device to obtain pyrolyzed powder; S4: screening the pyrolyzed powder by using the screening device to obtain aluminum current collectors and black powder; The gradient pyrolyzing process specifically comprises the following steps: S21: treating the shredded positive plate at 100-150 DEG C for 0.5-1 h; S22: then, increasing the temperature to 100-250 DEG C, and then introducing 100-250 DEG C superheated acid mist vapor to treat for 0.5-2 h.

8. The separating process of the positive tab of the waste lithium battery according to claim 7, characterized in that, In step S3, the rotation directions of the adjacent two pairs of rotation shafts of the dedusting device are opposite, and the rotation speeds of the rotation shafts are increased according to the contact sequence with the pyrolysis positive electrode fragments.

9. The separating process of the positive tab of the waste lithium battery according to claim 7, characterized in that, The flow of the superheated acid mist vapor is 1-3 kg / t, and the volume percentage of acid vapor in the superheated acid mist vapor is greater than 0 and less than or equal to 1 vol.%.

10. The separation process of the positive electrode sheet of the waste lithium battery according to claim 7, characterized in that, The separation process further comprises the step of treating the tail gas by using a tail gas treatment device.

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