Battery recovery process and recovery device

Abstract

The invention provides a battery recycling process and a battery recycling device, and relates to the technical field of battery recycling. The battery recovery process is used for respectively separating iron ions and lithium ions in a positive electrode coating of a lithium iron phosphate battery. The battery recovery process comprises the following steps: stripping the positive electrode coating from a positive electrode piece; iron ions in the positive electrode coating are separated; separating lithium ions in the positive electrode coating; wherein the step of separating the iron ions in the positive electrode coating comprises the following steps: adding the positive electrode coating and a leaching agent into a first reaction kettle; stirring the positive electrode coating and the leaching agent to mix the positive electrode coating and the leaching agent; ozone is introduced into the first reaction kettle from the bottom of the first reaction kettle. According to the battery recovery process and the recovery device provided by the invention, the recovery efficiency of the lithium iron material in the iron phosphate battery can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of battery recycling, and in particular to a battery recycling process and recycling device. Background Art

[0002] The White Paper on the Development of China's New Energy Vehicle Industry (2024) shows that global sales of new energy vehicles will reach 14.65 million in 2023, and global sales of new energy vehicles are expected to reach 47 million in 2030. According to data from the China Industrial Energy Conservation and Clean Production Association, the total number of retired lithium-ion batteries in my country will reach 142.2GWh in 2026, mainly lithium iron phosphate (LiFePO4), and its usage scenarios include power batteries and energy storage batteries. It can be seen that in 6-10 years, the volume of retired lithium iron phosphate batteries will be very large.

[0003] At present, the recycling of positive metals in waste lithium-ion batteries mostly adopts pyrometallurgical process, which is simple to operate and has low requirements for equipment. However, due to its high energy consumption (incineration temperature exceeds 1000℃) and secondary pollution, the research on wet process has attracted increasing attention. However, when using wet process to recycle lithium iron phosphate batteries, the recycling efficiency is low, and the purity of the recycled iron and lithium metals is not high, which is not suitable for the recycling and treatment needs of large-scale waste lithium iron phosphate batteries.

[0004] In summary, we urgently need a method to quickly and efficiently recycle iron-lithium materials from waste batteries. Summary of the invention

[0005] The present application provides a battery recycling process and a recycling device to improve the recovery efficiency of iron-lithium materials in iron phosphate batteries.

[0006] In a first aspect, the present application provides a battery recycling process for separating iron ions and lithium ions in a positive electrode coating of a lithium iron phosphate battery, respectively. The battery recycling process comprises:

[0007] The positive electrode coating is peeled off from the positive electrode sheet.

[0008] Separation of iron ions in the positive electrode coating.

[0009] Separates lithium ions in the positive electrode coating.

[0010] Among them, separation of iron ions in the positive electrode coating includes:

[0011] The positive electrode coating and the leaching agent are added into the first reactor.

[0012] The positive electrode coating and the leaching agent are stirred to mix the positive electrode coating and the leaching agent.

[0013] Ozone is introduced into the first reaction kettle from the bottom of the first reaction kettle.

[0014] The battery recycling process provided in the first aspect above, by introducing ozone into the first reactor from the bottom of the first reactor, so that the ozone contacts the mixed slurry of the positive electrode coating and the leaching agent in the process of overflowing upward, forming a longitudinal flow, and at the same time, stirring the mixed slurry of the positive electrode coating and the leaching agent, so that the mixed slurry produces a lateral flow, so that in the whole process of separating the iron ions in the positive electrode coating, the ozone can be quickly and uniformly and fully contacted with the mixed slurry in a short time, and the iron ions in the positive electrode coating are fully oxidized, and finally the iron ions in the mixed slurry are precipitated in the form of FePO4 powder, so that the iron ions and lithium ions in the positive electrode coating are separated, and the subsequent recycling of the iron ions and lithium ions is convenient. And the whole reaction process has the characteristics of being more sufficient and more efficient.

[0015] In a possible design, separating the iron ions in the positive electrode coating further includes: adjusting the pressure in the first reactor so that the gas pressure in the first reactor is higher than the atmospheric pressure.

[0016] Through the above scheme, the gas pressure in the first reactor is higher than the atmospheric pressure, which is conducive to further sufficient contact and reaction of ozone with the mixed slurry in the first reactor, and is conducive to further improving the separation and recovery efficiency of the lithium iron material in the positive electrode coating of the lithium iron phosphate battery.

[0017] In a possible design, when ozone is introduced into the first reactor from the bottom of the first reactor, the flow rate of ozone is 10-100 L / min.

[0018] Through the above scheme, when ozone participates in the chemical reaction in the first reactor, it can not only ensure sufficient supply of ozone, but also reduce the waste of ozone, taking into account both the recycling cost and recycling efficiency of the battery.

[0019] In one possible design, the leaching agent includes one or more of an organic acid and hydrogen peroxide.

[0020] According to the above scheme, the constituent elements of the organic acid are C (carbon), H (hydrogen), and O (oxygen), and the constituent elements of hydrogen peroxide are H and O. One or more of the organic acid and hydrogen peroxide are used as leaching agents, and the final product does not contain components composed of harmful chemical elements. Therefore, while the positive electrode coating is leached, no secondary pollution will be caused, and there is no need to further process the recycled waste products, which is beneficial to improving the environmental protection of battery recycling and reducing subsequent processing costs.

[0021] In a possible design, the organic acid includes any one or more of citric acid, ascorbic acid and oxalic acid.

[0022] In a possible design, the leaching agent includes at least two of citric acid, ascorbic acid, oxalic acid, and hydrogen peroxide, and one of the leaching agents is ascorbic acid.

[0023] Through the above scheme, the above leaching agent is used to participate in the separation and recovery of the positive electrode coating, which can improve the leaching efficiency of iron ions and lithium ions and improve the purity of the recovered lithium ions and iron ions.

[0024] In one possible design, separation of iron ions in the cathode coating also includes:

[0025] The first mixture after the reaction with ozone in the first reaction kettle is subjected to solid-liquid separation to separate solid FePO4 and liquid lithium-rich solution.

[0026] Separating lithium ions from the cathode coating involves:

[0027] The lithium-rich solution and the pH regulator containing carbonate are added to the second reaction kettle.

[0028] The lithium-rich solution and the pH regulator are stirred to mix the lithium-rich solution and the pH regulator, and the pH of the mixed solution is 9-11.

[0029] The second mixture in the second reaction kettle is subjected to solid-liquid separation to separate solid Li2CO3 and waste liquid.

[0030] Through the above scheme, the first mixture after the reaction with ozone in the first reactor is subjected to solid-liquid separation to separate solid FePO4 and liquid lithium-rich solution, and the separated FePO4 is convenient for recycling iron ions. In the alkaline environment in the second reactor, the carbonate in the pH regulator and the lithium ions in the lithium-rich solution are combined to form solid Li2CO3, and waste liquid is generated at the same time. The waste liquid does not contain inorganic acid and hydrogen peroxide, or the concentration of inorganic acid and / or hydrogen peroxide contained is small, and the possibility of causing environmental pollution is small. The solid Li2CO3 and the waste liquid are separated, and the separated Li2CO3 is convenient for recycling lithium ions. The above process generates FePO4 and Li2CO3 in different processes and reaction vessels, which is conducive to the separation of iron ions and lithium ions and improves the purity of FePO4 and Li2CO3.

[0031] In the second aspect, the present application provides a battery recycling device for separating iron ions and lithium ions in the positive electrode coating of a lithium iron phosphate battery, respectively. The battery recycling device comprises a first reactor and an ozone generator. The first reactor provides a reaction site for separating iron ions in the positive electrode coating, and a first stirring paddle is provided in the first reactor; the ozone generator is connected to the bottom of the first reactor to introduce ozone into the first reactor.

[0032] Through the above scheme, the ozone generator can introduce ozone into the first reactor from the bottom of the first reactor, so that the ozone overflows upward in the process of participating in the separation of iron ions in the positive electrode coating, and contacts with the mixed slurry of the positive electrode coating and the leaching agent in the process to form a longitudinal flow. The first stirring paddle can stir the mixed slurry of the positive electrode coating and the leaching agent in the process of separating the iron ions in the positive electrode coating, so that the mixed slurry produces a lateral flow and further contacts with the ozone, thereby quickly achieving uniform and sufficient contact between ozone and the mixed slurry in a short time, achieving sufficient oxidation of the iron ions in the positive electrode coating, and then achieving the separation of the iron ions and lithium ions in the positive electrode coating, facilitating the subsequent recycling of the iron ions and lithium ions, respectively, and the entire reaction process has the characteristics of being more sufficient and more efficient.

[0033] In a possible design, the battery recycling device further includes a second reactor and a connecting pipe. The second reactor provides a reaction site for separating lithium ions in the positive electrode coating, and a second stirring paddle is provided in the second reactor; one end of the connecting pipe is connected to the side wall or top wall of the first reactor, and the other end is connected to the bottom wall of the second reactor, so as to pass the gas in the first reactor into the second reactor.

[0034] Through the above scheme, the second stirring paddle stirs the material in the second reactor during the process of separating the lithium ions in the positive electrode coating, thereby improving the reaction efficiency. The gas in the first reactor contains ozone that has not been fully reacted. The gas in the first reactor is passed into the second reactor through a connecting pipe, which can make full use of the excess ozone. At the same time, in the process of separating the lithium ions in the positive electrode coating, the alkaline environment in the second reactor allows the ozone to form more oxidizing free radicals, which can re-oxidize and decompose the leaching agent in the liquid product produced in the first reactor, thereby avoiding excessive concentration of the waste liquid after the reaction in the second reactor. This setting has the effects of energy saving, environmental protection and cost saving.

[0035] In a possible design, the battery recycling device also includes a third reactor, which provides a reaction place for stripping the positive electrode coating from the positive electrode sheet. A filter is provided on the side wall of the third reactor, and the filter is used to hold the positive electrode sheet. A third stirring paddle is provided in the third reactor.

[0036] Through the above scheme, the filter is conducive to the peeled positive electrode coating falling off from the mesh holes. At the same time, the positive electrode collector is retained in the filter, which is conducive to the separation of the positive electrode collector and the positive electrode coating. The third stirring paddle can stir the stripping agent in the process of stripping the positive electrode coating from the positive electrode sheet, so that the positive electrode coating can be better infiltrated and flushed by the stripping agent, so as to achieve a more efficient separation of the positive electrode coating and the positive electrode collector, thereby improving the efficiency of the entire battery recycling process.

[0037] In summary, a battery recycling process and recycling device provided by an embodiment of the present application, by introducing ozone into the first reactor from the bottom of the first reactor, so that ozone contacts with the mixed slurry of the positive electrode coating and the leaching agent during the upward overflow, forming a longitudinal flow, and at the same time, stirring the mixed slurry of the positive electrode coating and the leaching agent, so that the mixed slurry produces a lateral flow, so that in the whole process of separating the iron ions in the positive electrode coating, the uniform and sufficient contact between ozone and the mixed slurry can be quickly achieved in a short time, and the iron ions in the positive electrode coating are fully oxidized, and finally the iron ions in the mixed slurry are precipitated in the form of FePO4 powder, so that the iron ions and lithium ions in the positive electrode coating are separated, and the subsequent recycling of iron ions and lithium ions is convenient. And the whole reaction process has the characteristics of being more sufficient and more efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A battery recycling process flow chart provided in an embodiment of the present application.

[0039] Figure 2 A schematic diagram of a battery recycling process and apparatus provided in an embodiment of the present application.

[0040] Figure 3 A process flow chart for stripping a positive electrode coating from a positive electrode plate is provided in an embodiment of the present application.

[0041] Figure 4 A process flow chart for separating iron ions in a positive electrode coating provided in an embodiment of the present application.

[0042] Figure 5 A process flow chart for separating lithium ions in a positive electrode coating provided in an embodiment of the present application.

[0043] Description of reference numerals:

[0044] 1000, first reactor; 1001, first stirring paddle; 2000, second reactor; 2001, second stirring paddle; 3000, third reactor; 3001, third stirring paddle; 3002, filter; 4000, ozone generator; 4001, gas tank; 4002, ozone generator; 5000, connecting pipe; 6000, pump; 7000, filter; 8000, exhaust valve. DETAILED DESCRIPTION

[0045] In order to make the invention purpose, technical scheme and beneficial technical effect of the present invention clearer, the present invention is further described in detail below in conjunction with examples and comparative examples. It should be understood that the embodiments described in this specification are only for explaining the present invention, not for limiting the present invention, and the formulas, proportions, etc. of the embodiments can be selected according to local conditions without substantial effect on the results.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification, claims and drawings of this application are intended to cover non-exclusive inclusions.

[0047] In the description of the present application, unless otherwise specified, "plurality" means more than two (including two), and similarly, "multiple groups" means more than two groups (including two).

[0048] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase "embodiments" in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0049] For simplicity, only some numerical ranges are explicitly disclosed herein. However, any lower limit can be combined with any upper limit to form an unambiguous range; and any lower limit can be combined with other lower limits to form an unambiguous range, and similarly, any upper limit can be combined with any other upper limit to form an unambiguous range. In addition, although not explicitly stated, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unambiguous range.

[0050] The above summary of the invention of the present invention is not intended to describe each disclosed embodiment or each implementation in the present invention. The following description more specifically illustrates exemplary embodiments. In many places throughout the application, guidance is provided by a series of examples, which can be used in various combinations. In each example and, enumeration is only as a representative group and should not be interpreted as exhaustive.

[0051] For lithium iron phosphate batteries, the main component of the positive electrode coating is lithium iron phosphate (LiFePO4). The lithium ions and iron ions in it must be recovered separately for reuse, and the most critical step is to separate the lithium ions and iron ions. In the related technology, the positive electrode coating is strongly oxidized by a strong acidic substance to leach out the metallic iron ions and metallic lithium ions. The leached metallic iron ions are recovered in the form of iron phosphate (FePO4), while the metallic lithium ions are finally recovered in the form of lithium carbonate (Li2CO3) by combining with the carbonate ions in the carbonate.

[0052] However, in the above-mentioned recovery process of the positive electrode coating, if the concentration of the strong acidic substance is too high, there will be dangers of corrosion, explosion, etc. during transportation, storage, and use, and the leaching equipment has high anti-corrosion requirements, resulting in a high overall process cost. If the concentration of the strong acidic substance is too low, the leaching efficiency of iron ions and lithium ions will be low, resulting in the inability to completely leach the metal ions in the positive electrode coating, and the recovery rate of the metal ions in the positive electrode coating is low.

[0053] In view of this, the present application provides a battery recycling process for separating the iron ions and lithium ions in the positive electrode coating of the lithium iron phosphate battery. Figure 1 and Figure 2 , the battery recycling process includes the following steps:

[0054] S100, peeling off the positive electrode coating from the positive electrode sheet.

[0055] The positive electrode sheet usually includes a positive electrode current collector and a positive electrode coating. The positive electrode coating adheres to both sides of the positive electrode current collector. The battery recycling process of the present application is mainly aimed at the recovery of iron ions and lithium ions in the positive electrode coating. Therefore, the positive electrode sheet needs to be processed first to peel off the positive electrode coating from the positive electrode sheet, so as to facilitate further separation of iron ions and lithium ions from the peeled positive electrode coating.

[0056] In some embodiments, Figure 2 and Figure 3 As shown, step S100 of stripping the positive electrode coating from the positive electrode sheet specifically includes:

[0057] S110, putting the positive electrode sheet into the third reaction kettle 3000.

[0058] S120, putting a stripping agent into the third reaction kettle 3000.

[0059] S130, stirring and heating the materials in the third reaction kettle 3000.

[0060] S140, taking out the positive electrode current collector;

[0061] S150, performing solid-liquid separation on the stripping material to obtain a stripping filtrate and a stripping residue, wherein the stripping residue mainly contains a positive electrode coating.

[0062] In S110, the positive electrode plate can be directly put into the bottom of the third reactor 3000, or a filter 3002 can be set, the positive electrode plate is placed in the filter 3002, and then the filter 3002 and the positive electrode plate are put into the third reactor 3000. In this way, in S140, the filter 3002 can be taken out, so that all the positive electrode current collectors are taken out together, which reduces the difficulty of taking out the positive electrode current collectors and improves the efficiency of the entire process.

[0063] In S120, the stripping agent can be a sodium hydroxide solution or deionized water, as long as the positive electrode coating can be soaked and removed from the positive electrode current collector. It is understandable that the use of sodium hydroxide solution as a stripping agent will have a higher stripping efficiency for the positive electrode coating. In addition, the input amount of the stripping agent is set according to the liquid-solid ratio of the stripping agent to the positive electrode sheet of 50-150L / g (liter per gram), and priority is given to ensuring that the stripping agent can completely submerge the positive electrode sheet.

[0064] Among them, when the stripping agent is a sodium hydroxide solution, the concentration of the sodium hydroxide solution is 0.5-2 mol / L (mole per liter). When the concentration of the sodium hydroxide solution is less than 0.5 mol / L, the stripping efficiency of the positive electrode coating will be low due to the insufficient concentration of the sodium hydroxide solution; when the concentration of the sodium hydroxide solution is greater than 2 mol / L, the cost will increase and the material will be wasted due to the high concentration of the sodium hydroxide solution. Therefore, setting the concentration of the sodium hydroxide solution to 0.5-2 mol / L can take into account both the stripping efficiency and cost of the positive electrode coating.

[0065] In S130, a third stirring paddle 3001 may be provided in the third reactor 3000, and the stirring paddle may be driven by a motor to rotate and stir the material in the third reactor 3000, so as to help the stripping agent flush the positive electrode coating, so as to improve the stripping efficiency of the positive electrode coating. Optionally, the speed of the stirring paddle is 500 to 1500 rpm, for example, the speed of the stirring paddle is 800 rpm, 1000 rpm, 1400 rpm, etc., and the specific speed is set according to the amount of material in the third reactor 3000 and the liquid-solid ratio.

[0066] In addition, in S130, the third reactor 3000 may be heated, specifically by water bath heating or electric heating. Specifically, the temperature in the third reactor 3000 may be maintained between 25-100° C. to improve the stripping efficiency of the positive electrode coating at a relatively high temperature.

[0067] Optionally, the time for performing S130 is 10 to 60 minutes, which can be flexibly changed according to the peeling condition of the positive electrode coating, and the embodiment of the present application does not limit this.

[0068] S150 can be carried out in the third reactor 3000, or the material in the third reactor 3000 can be pumped into the filter 7000 by the pump 6000, and the stripping material is separated into solid and liquid in the filter 7000. It can be understood that the stripping filtrate 1 mainly contains incompletely reacted stripping agent and reaction products of the stripping agent, and the stripping residue 1 will be used as the main raw material for recovering lithium ions and iron ions.

[0069] S200, separation of iron ions in the positive electrode coating.

[0070] like Figure 2 and Figure 4 As shown, in some embodiments, S200 specifically includes:

[0071] S210, adding the positive electrode coating and the leaching agent into the first reaction kettle 1000.

[0072] S220, stirring the positive electrode coating and the leaching agent to mix the positive electrode coating and the leaching agent.

[0073] S230 , introducing ozone into the first reaction kettle 1000 from the bottom of the first reaction kettle 1000 .

[0074] Among them, in S210, the positive electrode coating is specifically the stripping residue 1 obtained in S150, and can also be the positive electrode coating obtained by other stripping methods.

[0075] In a possible design, the leaching agent includes one or more of an organic acid and hydrogen peroxide. The organic acid may be any one or more of citric acid, ascorbic acid and oxalic acid.

[0076] According to the above scheme, the constituent elements of the organic acid are C (carbon), H (hydrogen), and O (oxygen), and the constituent elements of hydrogen peroxide are H and O. One or more of the organic acid and hydrogen peroxide are used as leaching agents, and the final product does not contain components composed of harmful chemical elements. Therefore, while the positive electrode coating is leached, no secondary pollution will be caused, and there is no need to further treat the waste product, which is beneficial to improving the environmental protection of battery recycling and reducing subsequent processing costs.

[0077] In a more specific design, the leaching agent includes at least two of citric acid, ascorbic acid, oxalic acid, and hydrogen peroxide, and one of the leaching agents is ascorbic acid.

[0078] Through the above scheme, the above leaching agent is used to participate in the separation and recovery of the positive electrode coating, which can improve the leaching efficiency of iron ions and lithium ions and improve the purity of the recovered lithium ions and iron ions.

[0079] It is understandable that S220 and S230 can be performed simultaneously or in any order without having a significant impact on the leaching effect.

[0080] In S220, a first stirring paddle 1001 may be provided in the first reactor 1000, and the first stirring paddle 1001 may be driven by a motor to stir the material in the first reactor 1000, so as to increase the sufficiency of the reaction of the material in the first reactor 1000. Optionally, the stirring time is 1 to 5 hours, which may be determined according to the amount of the material in the first reactor 1000.

[0081] In S230 , ozone may be dispersedly injected from the bottom of the first reactor 1000 in the form of micro-nano bubbles, so as to increase the probability of ozone contacting the material in the first reactor 1000 .

[0082] Optionally, ozone can be injected into the first reactor 1000 at a flow rate of 10 to 100 L / min, which may depend on the amount of material in the first reactor 1000. This solution ensures sufficient supply of ozone when ozone participates in the chemical reaction in the first reactor 1000, while reducing ozone waste, and taking into account both the recycling cost and recycling efficiency of the battery.

[0083] By introducing ozone into the first reactor 1000 from the bottom of the first reactor 1000, the ozone is in contact with the mixed slurry of the positive electrode coating and the leaching agent in the process of overflowing upward, forming a longitudinal flow, and at the same time, the mixed slurry of the positive electrode coating and the leaching agent is stirred, so that the mixed slurry produces a lateral flow, so that in the entire process of separating the iron ions in the positive electrode coating, the ozone can quickly achieve uniform and sufficient contact with the mixed slurry in a short time, and the iron ions in the positive electrode coating are fully oxidized, and finally the iron ions in the mixed slurry are precipitated in the form of FePO4 powder, so that the iron ions and lithium ions in the positive electrode coating are separated, and the subsequent recycling of the iron ions and lithium ions is convenient. And the whole reaction process has the characteristics of being more sufficient and more efficient.

[0084] like Figure 4 As shown, in some embodiments, S200 further includes:

[0085] S240, adjusting the pressure in the first reactor 1000 so that the gas pressure in the first reactor 1000 is higher than the atmospheric pressure.

[0086] Specifically, a connecting pipe 5000 and an exhaust valve 8000 are provided on the first reactor 1000. When ozone enters the first reactor 1000, the exhaust valve 8000 is closed, and the air pressure in the first reactor 1000 is monitored to gradually increase the air pressure in the first reactor 1000. When the air pressure is greater than a first threshold, the exhaust valve 8000 is opened to exhaust appropriately, and then the exhaust valve 8000 is closed. This process is repeated to maintain the air pressure in the first reactor 1000 within a range greater than the atmospheric pressure but lower than the first threshold to avoid danger.

[0087] For example, the local atmospheric pressure is 101 kPa (kilopascals) and the first threshold value is 130 kPa, then when the air pressure is higher than 130 kPa, the exhaust valve 8000 is opened to reduce the air pressure in the first reactor 1000 to between 101 and 130 kPa. When the air pressure in the first reactor 1000 is higher than 130 kPa again, the action of opening the exhaust valve 8000 is repeated, and finally the air pressure in the first reactor 1000 is always maintained between 101 and 130 kPa.

[0088] The above-mentioned step of adjusting the pressure in the first reactor 1000 so that the gas pressure in the first reactor 1000 is higher than the atmospheric pressure is conducive to further sufficient contact and reaction of ozone with the mixed slurry in the first reactor 1000, and is conducive to further improving the separation and recovery efficiency of the lithium iron material in the positive electrode coating of the lithium iron phosphate battery.

[0089] like Figure 4 As shown, in one possible design, S200 separates the iron ions in the positive electrode coating and further includes:

[0090] S250, performing solid-liquid separation on the first mixture after the reaction with ozone in the first reactor 1000 to separate solid FePO4 and liquid lithium-rich solution.

[0091] Specifically, the filter 7000 can be used for filtering, and the separated FePO4 is convenient for recycling iron ions. The liquid lithium-rich solution is subsequently processed to separate lithium ions.

[0092] S300, separates lithium ions from the positive electrode coating.

[0093] like Figure 5 As shown, in some embodiments, S300 specifically includes:

[0094] S310, adding the lithium-rich solution and the pH regulator containing carbonate into the second reaction kettle 2000.

[0095] S320, stirring the lithium-rich solution and the pH regulator to mix the lithium-rich solution and the pH regulator, and the pH of the mixed solution is 9-11.

[0096] S330, performing solid-liquid separation on the second mixture in the second reaction kettle 2000 to separate solid Li2CO3 and waste liquid 2.

[0097] In S310, the carbonate ion in the pH regulator may be provided by sodium carbonate and / or sodium bicarbonate, that is, the pH regulator includes at least one of sodium carbonate and sodium bicarbonate.

[0098] On the basis of the above-mentioned pH regulator components, the pH regulator may further include sodium hydroxide. Sodium hydroxide, as an alkaline solution without carbonate, can further adjust the pH of the lithium-rich solution without introducing carbonate.

[0099] In S320, a second stirring paddle 2001 may be provided in the second reaction kettle 2000, and the second stirring paddle 2001 may be driven to rotate by a motor to achieve stirring and mixing of the lithium-rich solution and the pH regulator.

[0100] In the alkaline environment of the second reactor 2000, the carbonate ions in the pH regulator and the lithium ions in the lithium-rich solution combine to form solid Li2CO3, and waste liquid 3 is generated at the same time. The waste liquid 3 does not contain inorganic acid and hydrogen peroxide, or the concentration of inorganic acid and / or hydrogen peroxide contained is relatively low, and the possibility of causing pollution to the environment is relatively small.

[0101] In S330, the filter 7000 can be used to separate the solid Li2CO3 and the waste liquid, and the separated Li2CO3 is convenient for recycling lithium ions.

[0102] The above processes S100-S300 generate FePO4 and Li2CO3 in different processes and reaction vessels, which is beneficial to the separation of iron ions and lithium ions and improves the purity of FePO4 and Li2CO3.

[0103] In some embodiments, in step S240, when the pressure in the first reactor 1000 is adjusted so that the gas pressure in the first reactor 1000 is higher than the atmospheric pressure, the gas in the first reactor 1000 can also be introduced into the second reactor 2000. In the process of separating the lithium ions in the positive electrode coating, the alkaline environment in the second reactor 2000 allows ozone to form free radicals with stronger oxidizing properties, which can re-oxidize and decompose the leaching agent in the lithium-rich solution, thereby avoiding excessive concentration of the waste liquid after the reaction in the second reactor 2000. This setting has the effects of energy saving, environmental protection and cost saving.

[0104] The present application also provides a battery recycling device for separating the iron ions and lithium ions in the positive electrode coating of the lithium iron phosphate battery. Figure 2 .

[0105] The battery recycling device includes a first reactor 1000 and an ozone generator 4000. The first reactor 1000 provides a reaction site for separating iron ions in the positive electrode coating, and a first stirring paddle 1001 is provided in the first reactor 1000; the ozone generator 4000 is connected to the bottom of the first reactor 1000 to introduce ozone into the first reactor 1000.

[0106] Through the above scheme, the ozone generator 4000 can pass ozone into the first reactor 1000 from the bottom of the first reactor 1000, so that the ozone overflows upward in the process of participating in the separation of iron ions in the positive electrode coating, and contacts with the mixed slurry of the positive electrode coating and the leaching agent in the process to form a longitudinal flow. The first stirring paddle 1001 can stir the mixed slurry of the positive electrode coating and the leaching agent in the process of separating the iron ions in the positive electrode coating, so that the mixed slurry produces a lateral flow and further contacts with ozone, thereby quickly achieving uniform and sufficient contact between ozone and the mixed slurry in a short time, achieving sufficient oxidation of the iron ions in the positive electrode coating, and then achieving the separation of iron ions and lithium ions in the positive electrode coating, facilitating the subsequent recycling of iron ions and lithium ions, respectively, and the whole reaction process has the characteristics of being more sufficient and more efficient.

[0107] Optionally, the ozone generating device 4000 includes a gas tank 4001 and an ozone generator 4002 which are connected to each other. The gas tank 4001 is an oxygen tank or an air tank. The ozone generator 4002 can use the gas in the gas tank 4001 to produce ozone and pass the ozone into the first reactor 1000, which is relatively low in cost.

[0108] like Figure 2 As shown, in a possible design, the battery recycling device further includes a second reactor 2000 and a connecting pipe 5000. The second reactor 2000 provides a reaction site for separating lithium ions in the positive electrode coating, and a second stirring paddle 2001 is provided in the second reactor 2000; one end of the connecting pipe 5000 is connected to the side wall or top wall of the first reactor 1000, and the other end is connected to the bottom wall of the second reactor 2000, so as to pass the gas in the first reactor 1000 into the second reactor 2000.

[0109] The second stirring paddle 2001 stirs the material in the process of separating the lithium ions in the positive electrode coating in the second reactor 2000 to improve the reaction efficiency. The gas in the first reactor 1000 contains ozone that has not reacted fully. The gas in the first reactor 1000 is passed into the second reactor 2000 through the connecting pipe 5000, which can make full use of the excess ozone. At the same time, in the process of separating the lithium ions in the positive electrode coating, the alkaline environment in the second reactor 2000 allows the ozone to form more oxidizing free radicals, which can re-oxidize and decompose the leaching agent in the liquid product produced in the first reactor 1000, avoiding the concentration of the waste liquid after the reaction in the second reactor 2000 to be too high. This setting has the functions of energy saving, environmental protection and cost saving.

[0110] like Figure 2 As shown, in a possible design, the battery recycling device also includes a third reactor 3000, which provides a reaction place for stripping the positive electrode coating from the positive electrode sheet. A filter screen 3002 is provided on the side wall of the third reactor 3000, and the filter screen 3002 is used to hold the positive electrode sheet. A third stirring paddle 3001 is provided in the third reactor 3000.

[0111] The filter screen 3002 facilitates the peeled positive electrode coating to fall off from the mesh, while the positive electrode current collector is retained in the filter screen 3002, thereby facilitating the separation of the positive electrode current collector and the positive electrode coating.

[0112] The third stirring paddle 3001 can stir the stripping agent during the process of stripping the positive electrode coating from the positive electrode plate, so that the positive electrode coating is better infiltrated and flushed by the stripping agent, so as to achieve a more efficient separation of the positive electrode coating and the positive electrode current collector, thereby improving the efficiency of the entire battery recycling process.

[0113] Optionally, the battery recycling device further comprises at least three groups of pumps 6000 and filters 7000. The three pumps 6000 are respectively connected to the first reactor 1000, the second reactor 2000 and the third reactor 3000 to extract the materials after the reaction in each reactor. The filter 7000 is used to receive the materials extracted by the pump 6000 and separate them into filter residue and filtrate to be transported to the corresponding reactor. For details, please refer to Figure 2 .

[0114] The effect of the above battery recycling process on recovering iron and lithium is described below through multiple groups of examples and comparative examples.

[0115] The following examples more specifically describe the disclosure of the present invention, which are intended for illustrative purposes only, as various modifications and variations within the scope of the present disclosure are apparent to those skilled in the art. Unless otherwise stated, all mass fractions, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available and can be used directly without further processing.

[0116] Example 1

[0117] The discarded LFP (LiFePO4, lithium iron phosphate) electrode is placed in the filter 3002 of the third reactor 3000, and 2 mol / L of stripping agent sodium hydroxide is introduced into the third reactor 3000, with a solid-liquid ratio of 50 L / g. Stirring and heating are started, the speed is 1000 rpm, and the temperature is 100 ° C. After 20 minutes, the aluminum foil in the filter 3001 is taken out, and the pump 6000 and the filter 7000 connected to the back of the third reactor 3000 are opened for solid-liquid separation. The filtrate 1 generated is the stripping wastewater. The filter residue 1 generated is placed in the first reactor, the oxygen tank is turned on, the ozone generator 4002 is turned on, the ozone flow rate is 30 L / min, and 3 mol / L of the composite leaching agent citric acid + anti-corrosive is introduced. Blood acid (concentration ratio of 5:1), solid-liquid ratio of 30L / g, start stirring, after 4h, open the exhaust valve 8000 on the connecting pipe 5000 and adjust the flow rate to control the pressure in the first reactor 1000, turn on the pump 6000 and the filter 7000 connected to the first reactor 1000 for solid-liquid separation, the filter residue 2 is FePO4 black powder, and the filtrate 2 is a lithium-rich solution. Turn on the pump on the filter, pass the lithium-rich solution into the second reactor, start stirring, and pass the regulator sodium carbonate to adjust the pH to 10. After 50min, turn on the pump 6000 and the filter 7000 connected to the second reactor 2000 for solid-liquid separation, the filter residue 3 is Li2CO3 white powder, and the filtrate 3 is waste water.

[0118] Example 2

[0119] Place the discarded LFP pole piece in the filter 3002 of the third reactor 3000, and introduce 2 mol / L stripping agent sodium hydroxide into the third reactor 3000, with a solid-liquid ratio of 50 L / g. Start stirring and heating at a speed of 1000 rpm and a temperature of 100°C. After 20 minutes, take out the aluminum foil in the filter 3002, open the pump 6000 and the filter 7000 connected to the third reactor 3000 for solid-liquid separation, and the generated filtrate 1 is stripping wastewater. Place the generated filter residue 1 in the first reactor 1000, open the oxygen tank, turn on the ozone generator 4002, and introduce 3 mol / L composite leaching agent citric acid + ascorbic acid (concentration ratio of 5:1). The solid-liquid ratio is 30L / g, and stirring is turned on. After 4 hours, the exhaust valve 8000 on the connecting pipe 5000 is opened and the flow rate is adjusted to control the pressure in the first reactor 1000. The pump 6000 and the filter 7000 connected to the first reactor 1000 are turned on for solid-liquid separation. The filter residue 2 is FePO4 black powder, and the filtrate 2 is a lithium-rich solution. The pump 6000 on the filter 7000 is turned on, and the lithium-rich solution is passed into the second reactor 2000. Stirring is turned on, and sodium bicarbonate as a regulator is passed to adjust the pH to 10. After 50 minutes, the pump 6000 and the filter 7000 connected to the second reactor 2000 are turned on for solid-liquid separation. The filter residue 3 is Li2CO3 white powder, and the filtrate 3 is waste water.

[0120] Example 3

[0121] Place the discarded LFP pole piece in the filter 3002 of the third reactor 3000, and introduce 2 mol / L stripping agent sodium hydroxide into the third reactor 3000, with a solid-liquid ratio of 50 L / g. Start stirring and heating at a speed of 1200 rpm and a temperature of 50°C. After 20 minutes, take out the aluminum foil in the filter 3002, open the pump 6000 and the filter 7000 connected to the third reactor 3000 for solid-liquid separation, and the generated filtrate 1 is stripping wastewater. Place the generated filter residue 1 in the first reactor 1000, open the oxygen tank, turn on the ozone generator 4002, and introduce 5 mol / L composite leaching agent ascorbic acid + hydrogen peroxide (concentration ratio of 5:1). The solid-liquid ratio is 30L / g, and stirring is turned on. After 3 hours, the exhaust valve 8000 on the connecting pipe 5000 is opened and the flow rate is adjusted to control the pressure in the first reactor 1000. The pump 6000 and the filter 7000 connected to the first reactor 1000 are turned on for solid-liquid separation. The filter residue 2 is FePO4 black powder, and the filtrate 2 is a lithium-rich solution. The pump 6000 on the filter 7000 is turned on, and the lithium-rich solution is passed into the second reactor 2000. Stirring is turned on, and sodium carbonate as a regulator is passed to adjust the pH to 10. After 40 minutes, the pump 6000 and the filter 7000 connected to the second reactor 2000 are turned on for solid-liquid separation. The filter residue 3 is Li2CO3 white powder, and the filtrate 3 is waste water.

[0122] Example 4

[0123] Place the discarded LFP pole piece in the filter 3002 of the third reactor 3000, and introduce 2 mol / L stripping agent sodium hydroxide into the third reactor 3000, with a solid-liquid ratio of 50 L / g. Start stirring and heating at a speed of 1200 rpm and a temperature of 50°C. After 20 minutes, take out the aluminum foil in the filter 3002, open the pump 6000 and the filter 7000 connected to the third reactor 3000 for solid-liquid separation, and the generated filtrate 1 is stripping wastewater. Place the generated filter residue 1 in the first reactor 1000, open the oxygen tank, turn on the ozone generator 4002, and introduce 5 mol / L composite leaching agent oxalic acid + ascorbic acid (concentration ratio of 5:1). The solid-liquid ratio is 30L / g, and stirring is turned on. After 3 hours, the exhaust valve 8000 on the connecting pipe 5000 is opened and the flow rate is adjusted to control the pressure in the first reactor 1000. The pump 6000 and the filter 7000 connected to the first reactor 1000 are turned on for solid-liquid separation. The filter residue 2 is FePO4 black powder, and the filtrate 2 is a lithium-rich solution. The pump 6000 on the filter 7000 is turned on, and the lithium-rich solution is passed into the second reactor 2000. Stirring is turned on, and sodium carbonate as a regulator is passed to adjust the pH to 10. After 40 minutes, the pump 6000 and the filter 7000 connected to the second reactor 2000 are turned on for solid-liquid separation. The filter residue 3 is Li2CO3 white powder, and the filtrate 3 is waste water.

[0124] Comparative Example 1

[0125] Place the discarded LFP pole piece in the filter 3002 of the third reactor 3000, and introduce 2mol / L stripping agent sodium hydroxide into the third reactor 3000, with a solid-liquid ratio of 150L / g. Start stirring and heating, with a rotation speed of 1200rpm and a temperature of 50°C. After 20 minutes, take out the aluminum foil in the filter 3002, open the pump 6000 and the filter 7000 connected to the third reactor 3000 for solid-liquid separation, and the generated filtrate 1 is stripping wastewater. Place the generated filter residue 1 in the first reactor 1000, open the oxygen tank, do not open the ozone generator 4002, the oxygen flow rate is 30L / min, and introduce 5mol / L composite leaching agent oxalic acid + ascorbic acid (concentration ratio is 5:1) , the solid-liquid ratio is 30L / g, stirring is started, after 3h, the exhaust valve 8000 on the connecting pipe 5000 is opened and the flow rate is adjusted to control the pressure in the first reactor 1000, the pump 6000 and the filter 7000 connected to the first reactor 1000 are turned on for solid-liquid separation, the filter residue 2 is FePO4 black powder, and the filtrate 2 is a lithium-rich solution. The pump 6000 on the filter 7000 is turned on, and the lithium-rich solution is passed into the second reactor 2000, stirring is started, and sodium carbonate as a regulator is passed to adjust the pH to 10. After 40min, the pump 6000 and the filter 7000 connected to the second reactor 2000 are turned on for solid-liquid separation, the filter residue 3 is Li2CO3 white powder, and the filtrate 3 is waste water.

[0126] Comparative Example 2

[0127] The discarded LFP pole piece is placed in the filter 3002 of the third reactor 3000, and the stripping agent deionized water is introduced into the third reactor 3000 with a solid-liquid ratio of 50L / g. Stirring and heating are started at a speed of 1000rpm and a temperature of 100°C. After 40 minutes, the aluminum foil in the filter 3002 is taken out, and the pump 6000 and the filter 7000 connected to the third reactor 3000 are opened for solid-liquid separation. The generated filtrate 1 is the stripping wastewater. The generated filter residue 1 is placed in the first reactor 1000 without any gas, and 3 mol / L leaching agent citric acid is introduced into the first reactor 1000 with a solid-liquid ratio of 30L / g. Stirring is started for 3h. Afterwards, open the exhaust valve 8000 on the connecting pipe 5000 and adjust the flow rate to control the pressure in the first reactor 1000, turn on the pump 6000 and the filter 7000 connected to the first reactor 1000 for solid-liquid separation, the filter residue 2 is FePO4 black powder, and the filtrate 2 is a lithium-rich solution. Turn on the pump 6000 on the filter 7000, pass the lithium-rich solution into the second reactor 2000, start stirring, and pass the regulator sodium carbonate to adjust the pH to 10. After 50 minutes, turn on the pump 6000 and the filter 7000 connected to the second reactor 2000 for solid-liquid separation, the filter residue 3 is Li2CO3 white powder, and the filtrate 3 is waste water.

[0128] Comparative Example 3

[0129] Place the discarded LFP pole piece in the filter 3002 of the third reactor 3000, introduce stripping agent deionized water into the third reactor 3000, start stirring and heating, the speed is 1200rpm, the temperature is 50℃, after 20 minutes, take out the aluminum foil in the filter 3002, open the pump 6000 and filter 7000 connected to the third reactor 3000 for solid-liquid separation, the generated filtrate 1 is the stripping wastewater, place the generated filter residue 1 in the first reactor 1000, turn on the oxygen tank, turn on the ozone generator 4002, the ozone flow rate is 30L / min, pass 5mol / L composite leaching agent oxalic acid + ascorbic acid (concentration ratio is 5:1), the solid-liquid ratio is 30L / g , start stirring, after 3 hours, open the exhaust valve 8000 on the connecting pipe 5000 and adjust the flow rate to control the pressure in the first reactor 1000, turn on the pump 6000 and the filter 7000 connected to the first reactor 1000 for solid-liquid separation, the filter residue 2 is FePO4 black powder, and the filtrate 2 is a lithium-rich solution, turn on the pump 6000 on the filter 7000, and pass the lithium-rich solution into the second reactor 2000, start stirring, and pass the regulator sodium carbonate to adjust the pH to 10. After 40 minutes, turn on the pump 6000 and the filter 7000 connected to the second reactor 2000 for solid-liquid separation, the filter residue 3 is Li2CO3 white powder, and the filtrate 3 is waste water.

[0130] Comparative Example 4

[0131] Place the discarded LFP pole piece in the filter 3002 of the third reactor 3000, and introduce 2 mol / L of stripping agent sodium hydroxide into the third reactor 3000 with a solid-liquid ratio of 50 L / g. Start stirring and heating at a speed of 1200 rpm and a temperature of 50°C. After 20 minutes, take out the aluminum foil in the filter 3002, open the pump 6000 and the filter 7000 connected to the third reactor 3000 for solid-liquid separation, and the generated filtrate is stripping wastewater. Place the generated filter residue 1 in the first reactor 1000, turn on the oxygen tank, turn on the ozone generator 4002, the ozone flow rate is 30 L / min, and introduce 5 mol / L composite leaching ascorbic acid with a solid-liquid ratio of 30 L / g. / g, start stirring, after 3h, open the exhaust valve 8000 on the connecting pipe 5000 and adjust the flow rate to control the pressure in the first reactor 1000, turn on the pump 6000 and the filter 7000 connected to the first reactor 1000 for solid-liquid separation, the filter residue 2 is FePO4 black powder, and the filtrate 2 is a lithium-rich solution, turn on the pump 6000 on the filter 7000, pass the lithium-rich solution into the second reactor 2000, start stirring, and pass the regulator sodium carbonate to adjust the pH to 10, after 40min, turn on the pump 6000 and the filter 7000 connected to the second reactor 2000 for solid-liquid separation, the filter residue 3 is Li2CO3 white powder, and the filtrate 3 is waste water.

[0132] Comparative Example 5

[0133] Place the discarded LFP pole piece in the filter 3002 of the third reactor 3000, and introduce 2mol / L stripping agent sodium hydroxide into the third reactor 3000 with a solid-liquid ratio of 50L / g. Start stirring and heating at a speed of 1200rpm and a temperature of 50°C. After 20 minutes, take out the aluminum foil in the filter 3002, open the pump 6000 and the filter 7000 connected to the third reactor 3000 for solid-liquid separation, and the generated filtrate 1 is the stripping wastewater. Place the generated filter residue 1 in the first reactor 1000, turn on the oxygen tank, turn on the ozone generator 4002, and introduce 5mol / L composite leaching agent oxalic acid with a solid-liquid ratio of 30L. / g, start stirring, after 3h, open the exhaust valve 8000 on the connecting pipe 5000 and adjust the flow rate to control the pressure in the first reactor 1000, turn on the pump 6000 and the filter 7000 connected to the first reactor 1000 for solid-liquid separation, the filter residue 2 is FePO4 black powder, and the filtrate 2 is a lithium-rich solution, turn on the pump 6000 on the filter 7000, pass the lithium-rich solution into the second reactor 2000, start stirring, and pass the regulator sodium carbonate to adjust the pH to 10, after 40min, turn on the pump 6000 and the filter 7000 connected to the second reactor 2000 for solid-liquid separation, the filter residue 3 is Li2CO3 white powder, and the filtrate 3 is waste water.

[0134] The main parameters of the above-mentioned Examples 1 to 4 and Comparative Examples 1 to 5 are selected as shown in Table 1 below.

[0135] Testing Process

[0136] After the above-mentioned residue 2 and residue 3 were dissolved with dilute hydrochloric acid, ICP (Inductively Coupled Plasma) test was performed, and the leaching efficiency of lithium and iron was calculated according to the following formula.

[0137] ζ 铁1 =56*b1V1C 11 / (1000x1km)

[0138] ζ 锂1 =7*b1V1C 12 / (1000x2km)

[0139] ζ 铁1 is the leaching efficiency of iron in the filter residue 2; ζ 锂1 is the leaching efficiency of lithium in the filter residue 2; V1 is the volume of the solution after the filter residue 2 is dissolved in dilute hydrochloric acid in the ICP test, in mL (milliliter); C 11 is the concentration of Fe in the solution after the filter residue 2 is dissolved in dilute hydrochloric acid in the ICP test, in mol / L (mole per liter); C 12is the concentration of Li in the solution after the filter residue 2 in the ICP test is dissolved in dilute hydrochloric acid, in mol / L; b1 is the mass ratio of the filter residue 2 used in the ICP test to the total filter residue 2; k is the mass percentage of lithium iron phosphate in the positive electrode coating in the positive electrode sheet; x1 is the mass percentage of Fe in lithium iron phosphate; x2 is the mass percentage of Li in lithium iron phosphate; m is the mass of the positive electrode coating in the positive electrode sheet, in kg (kilogram).

[0140] ζ 铁2 =56*b2V2C 21 / (1000x1km)

[0141] ζ 锂2 =7*b2V2C 22 / (1000x2km)

[0142] ζ 铁2 is the leaching efficiency of iron in the filter residue 3; ζ 锂2 is the leaching efficiency of lithium in the residue 3; V2 is the volume of solution after the residue 3 is dissolved by dilute hydrochloric acid in the ICP test, in mL; C 21 is the Fe concentration in the solution after the filter residue 3 is dissolved in dilute hydrochloric acid in the ICP test, in mol / L; C 22 is the concentration of Li in the solution after the filter residue 3 in the ICP test is dissolved in dilute hydrochloric acid, in mol / L; b2 is the mass ratio of the filter residue 3 used in the ICP test to the total filter residue 3; k is the mass percentage of lithium iron phosphate in the positive electrode coating in the positive electrode sheet; x1 is the mass percentage of Fe in lithium iron phosphate; x2 is the mass percentage of Li in lithium iron phosphate; m is the mass of the positive electrode coating in the positive electrode sheet, in kg.

[0143] The data obtained from the above tests are recorded in Tables 2 and 3 below, wherein Table 2 records the leaching efficiency of lithium and iron in the filter residue 2 of different embodiments and comparative examples, and Table 3 records the leaching efficiency of lithium and iron in the filter residue 3 of different embodiments and comparative examples.

[0144] Table 1

[0145]

[0146]

[0147] Table 2

[0148] Recycling Program <![CDATA[Leaching efficiency ζ of lithium 锂1 (%)]]> <![CDATA[Leaching efficiency ζ of iron 铁1 (%)]]> Example 1 1.24 98.51 Example 2 2.37 97.22 Example 3 1.19 97.06 Example 4 1.55 98.24 Comparative Example 1 5.34 89.80 Comparative Example 2 9.14 86.55 Comparative Example 3 8.21 89.05 Comparative Example 4 7.93 88.09 Comparative Example 5 8.24 87.42

[0149] Table 3

[0150] Recycling Program <![CDATA[Leaching efficiency ζ of lithium 锂2 (%)]]> <![CDATA[Leaching efficiency ζ of iron 铁2 (%)]]> Example 1 99.07 2.09 Example 2 97.31 1.87 Example 3 98.54 1.93 Example 4 97.63 3.54 Comparative Example 1 90.64 5.73 Comparative Example 2 83.26 8.18 Comparative Example 3 83.77 4.23 Comparative Example 4 85.72 6.02 Comparative Example 5 83.54 7.29

[0151] It should be noted that in Table 2, the leaching efficiency of iron in the filter residue 2 is铁1 Represents the recovery rate of iron in the recovery scheme. The lithium in the filter residue 2 exists as an impurity in the recovered iron. Therefore, for the leaching efficiency of lithium and iron in the filter residue 2, the leaching efficiency of iron is ζ 铁1 The higher the value, the higher the iron recovery rate of the corresponding recovery scheme; the lithium leaching efficiency ζ 锂1 The lower it is, the higher the purity of the recovered iron in the corresponding recovery plan and the less impurities.

[0152] In Table 3, the leaching efficiency of lithium in the residue 3 is 锂2 Represents the recovery rate of lithium in the recovery scheme. The iron in the filter residue 3 exists as an impurity in the recovered lithium. Therefore, for the leaching efficiency of lithium and iron in the filter residue 3, the leaching efficiency of lithium is ζ 锂2 The higher the value, the higher the lithium recovery rate of the corresponding recovery scheme; the iron leaching efficiency ζ 铁2 The lower it is, the higher the purity of the recovered lithium and the less impurities in the corresponding recovery plan.

[0153] By comparing the four embodiments with the five comparative examples, it can be seen that when the recovery scheme is that the stripping agent is sodium hydroxide solution, the leaching agent is at least two of citric acid, ascorbic acid, oxalic acid, and hydrogen peroxide, and one of them is ascorbic acid, and at the same time, when ozone is introduced into the first reactor, the recovery rates of iron and lithium are both greater than 97%, and the purity of the recovered iron and the purity of the recovered lithium are much higher than those of the recovery scheme of the comparative example.

[0154] The other main recovery conditions of Example 4 and Comparative Example 1 remain unchanged, and the main difference is that in Example 4, oxidizing gas ozone is introduced into the first reactor, and in Comparative Example 1, oxidizing gas oxygen is introduced into the first reactor. In this case, the recovery rates of iron and lithium in Example 4 are much greater than those in Comparative Example 1, and the purity of recovered iron and recovered lithium in Example 4 is greater than that in Comparative Example 1. It can be seen that adding ozone during the leaching process can significantly improve the recovery rate and recovery purity of iron and lithium in the battery. It can be understood that if no oxidizing gas is added during the leaching process, or air is added, the recovery rate and recovery purity of iron and lithium will be lower.

[0155] The other main recovery conditions of Example 1 and Example 2 remain unchanged, only the ozone flow rate is different. By comparing Example 1 and Example 2, it can be seen that the recovery rates of iron and lithium in Example 1 with an ozone flow rate of 30 are greater than the recovery rates of iron and lithium in Example 2 with an ozone flow rate of 5. It can be seen that if only the ozone flow rate is changed, the recovery rate of iron and lithium will be higher in the recovery scheme with a larger ozone flow rate.

[0156] Compared with Comparative Example 4 and Comparative Example 5, Example 1, Example 3 and Example 4 are different only in that the composite leaching agent comprising ascorbic acid is used in Example 1, Example 3 and Example 4, the single leaching agent ascorbic acid is used in Comparative Example 4, and the single leaching agent oxalic acid is used in Comparative Example 5. In this case, although the recovery rates of iron and lithium in Example 1, Example 3 and Example 4 are slightly different due to the different combinations of composite leaching agents, the overall difference is not large, and they are all at a high level, while the recovery rates of iron and lithium in Comparative Example 4 and Comparative Example 5 are both low. It can be seen that when the leaching agent adopts at least two of citric acid, ascorbic acid, oxalic acid and hydrogen peroxide, and one of them is ascorbic acid, the leaching efficiency of iron ions and lithium ions can be improved, thereby improving the recovery rate of iron and lithium, and improving the purity of the recovered lithium ions and iron ions.

[0157] The other main recovery conditions of Example 4 and Comparative Example 3 remain unchanged, only the stripping agent is different. The stripping agent in Example 4 is sodium hydroxide solution, and the stripping agent in Comparative Example 3 is deionized water. Compared with Comparative Example 3, the recovery rate and recovery purity of iron and lithium in Example 4 are greater than those in Comparative Example 3. It can be seen that the use of sodium hydroxide as a stripping agent is more conducive to improving the recovery rate and recovery purity of iron and lithium in the battery.

[0158] In the above embodiments and comparative examples, the stripping agent of comparative example 2 is deionized water, the leaching agent is single citric acid, and no oxidizing gas is introduced into the first reaction kettle. It can be clearly seen from Table 2 and Table 3 that the ζ 铁1 is 86.55%, the smallest among all recycling schemes. 锂1 is 9.14%, the largest among all recycling schemes. 锂2 is 83.26%, the smallest among all recovery schemes. 铁2 It is 8.18%, the largest among all the recovery schemes, which reflects that the recovery rate and recovery purity of iron and lithium in Comparative Example 2 are the lowest among all the schemes. It can be seen that when the stripping agent does not use the sodium hydroxide solution in the embodiment of the present application, the leaching agent does not use the composite leaching agent containing ascorbic acid, and ozone is not introduced into the first reactor, a superimposed effect will be produced, which will significantly deteriorate the recovery rate and recovery purity of iron and lithium in the battery.

[0159] In summary, a battery recycling process and recycling device provided by an embodiment of the present application, by introducing ozone into the first reactor from the bottom of the first reactor, so that ozone contacts with the mixed slurry of the positive electrode coating and the leaching agent during the upward overflow, forming a longitudinal flow, and at the same time, stirring the mixed slurry of the positive electrode coating and the leaching agent, so that the mixed slurry produces a lateral flow, so that in the whole process of separating the iron ions in the positive electrode coating, the uniform and sufficient contact between ozone and the mixed slurry can be quickly achieved in a short time, and the iron ions in the positive electrode coating are fully oxidized, and finally the iron ions in the mixed slurry are precipitated in the form of FePO4 powder, so that the iron ions and lithium ions in the positive electrode coating are separated, and the subsequent recycling of iron ions and lithium ions is convenient. And the whole reaction process has the characteristics of being more sufficient and more efficient.

Claims

1. A battery recycling process for separating iron ions and lithium ions in the positive electrode coating of a lithium iron phosphate battery, characterized in that: The process comprises: Stripping the positive electrode coating from the positive electrode sheet; Separating iron ions in the positive electrode coating; Separating lithium ions in the positive electrode coating; Wherein, the iron ions in the separation positive electrode coating include: Adding the positive electrode coating and the leaching agent into a first reaction kettle; Stirring the positive electrode coating and the leaching agent to mix the positive electrode coating and the leaching agent; Ozone is introduced into the first reaction kettle from the bottom of the first reaction kettle.

2. The battery recycling process according to claim 1, characterized in that: The iron ions in the separation positive electrode coating further include: The pressure in the first reaction kettle is adjusted so that the gas pressure in the first reaction kettle is higher than the atmospheric pressure.

3. The battery recycling process according to claim 1, characterized in that: When ozone is introduced into the first reactor from the bottom of the first reactor, the flow rate of the ozone is 10-100 L / min.

4. The battery recycling process according to claim 1, characterized in that: The leaching agent includes one or more of an organic acid and hydrogen peroxide.

5. The battery recycling process according to claim 4, characterized in that: The organic acid includes any one or more of citric acid, ascorbic acid and oxalic acid.

6. The battery recycling process according to claim 5, characterized in that: The leaching agent includes at least two of citric acid, ascorbic acid, oxalic acid and hydrogen peroxide, and one of them is ascorbic acid.

7. The battery recycling process according to claim 1, characterized in that: The iron ions in the separation positive electrode coating further include: Performing solid-liquid separation on the first mixture after the reaction with the ozone in the first reactor to separate solid FePO4 and liquid lithium-rich solution; The separating of lithium ions in the positive electrode coating comprises: Adding the lithium-rich solution and a pH regulator containing carbonate into a second reaction kettle; Stirring the lithium-rich solution and the pH regulator to mix the lithium-rich solution and the pH regulator, and the pH of the mixed solution is 9-11; The second mixture in the second reaction kettle is subjected to solid-liquid separation to separate solid Li2CO3 and waste liquid.

8. A battery recycling device for separating iron ions and lithium ions in the positive electrode coating of a lithium iron phosphate battery, characterized in that: include: a first reactor, wherein the first reactor provides a reaction site for separating iron ions in the positive electrode coating, and a first stirring paddle is provided in the first reactor; An ozone generating device is connected to the bottom of the first reaction kettle to introduce ozone into the first reaction kettle.

9. The battery recycling device according to claim 8, characterized in that: Also includes: A second reactor, the second reactor provides a reaction site for separating lithium ions in the positive electrode coating, and a second stirring paddle is provided in the second reactor; A connecting pipe has one end connected to the side wall or top wall of the first reactor and the other end connected to the bottom wall of the second reactor, so as to pass the gas in the first reactor into the second reactor.

10. The battery recycling device according to claim 9, characterized in that: Also includes: The third reactor provides a reaction place for stripping the positive electrode coating from the positive electrode sheet. A filter is provided on the side wall of the third reactor, and the filter is used to hold the positive electrode sheet. A third stirring paddle is provided in the third reactor.

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