A method for redox leaching of battery black powder based on electron beam irradiation-induced free radicals and its application

Abstract

This invention proposes a method for leaching battery black powder based on electron beam irradiation-induced free radical redox leaching and its application. The method includes the following steps: S1: mixing black powder with ammonia-alkali solution to obtain a slurry, irradiating the slurry with an electron beam under an oxygen-deficient atmosphere, and obtaining filter residue and target metal enrichment solution after solid-liquid separation; wherein, the black powder contains at least one metal element selected from nickel or cobalt, and the molar ratio of nickel and / or cobalt to ammonium ions in the ammonia-alkali solution is not higher than 1:6; the pH of the ammonia-alkali solution is 9-11, and c(NH4)2 is 10 ... + The concentration of the oxygen in the atmosphere is 1-4 mol / L; the oxygen-deficient atmosphere refers to an oxygen content of less than 3%; the electron beam irradiation conditions are: energy of 1-3 MeV and dose of 20-100 kGy. This method can reduce the loss of chemical reagents and energy consumption, achieve highly selective leaching of target metals, shorten the process flow, and simultaneously repair graphite.

Description

Technical Field

[0001] This invention relates to the field of resource recycling technology, specifically to a method for leaching battery black powder based on electron beam irradiation-induced free radical redox leaching and its application. Background Technology

[0002] With the widespread adoption of electric vehicles and portable electronic devices, the number of spent lithium-ion batteries has surged. Battery black powder is a mixed powder of positive and negative electrode materials obtained after the spent lithium-ion batteries have been crushed and sorted. It is rich in valuable metals such as lithium, cobalt, nickel, and manganese. Efficient and environmentally friendly recycling of these metals is of great significance for resource recycling and environmental protection.

[0003] Currently, the leaching of battery black powder mainly employs hydrometallurgical techniques, including acid leaching and reductive leaching. Traditional acid leaching methods (such as using sulfuric acid or hydrochloric acid) typically require high-concentration acids and long reaction times, and are highly corrosive to equipment, resulting in high costs for waste gas and waste liquid treatment. To dissolve high-valence metal oxides, chemical reducing agents (such as hydrogen peroxide or sodium sulfite) are often added, increasing reagent costs and process complexity, and potentially introducing impurities.

[0004] Electron beam irradiation is an advanced oxidation / reduction process (AOPs / ARPs). When a high-energy electron beam acts on an aqueous solution, it can instantly generate highly reactive free radicals (such as ·OH, e-). - Electron beam irradiation (Aq, H) and its molecular products (such as H₂O₂) are active species. These species possess strong redox capabilities and can theoretically replace or partially replace traditional chemical reagents to achieve oxidative dissolution or reductive leaching of metals. However, effectively coupling electron beam irradiation technology with battery black powder leaching processes, designing reasonable irradiation-reaction systems, and controlling the generation and reaction pathways of free radicals to achieve efficient and selective leaching of valuable metals while reducing energy consumption and environmental pollution remains a pressing technical challenge in this field.

[0005] Therefore, this invention is proposed. Summary of the Invention

[0006] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a method for leaching battery black powder based on electron beam irradiation-induced free radical redox leaching and its application. This method can reduce the consumption of chemical reagents and energy, achieve highly selective leaching of target metals (at least one of nickel, cobalt, and lithium), shorten the process flow, and simultaneously repair graphite.

[0007] According to a first aspect of the present invention, a method for leaching battery black powder is provided, comprising the following steps: S1: Mix black powder with ammonia-alkali solution to obtain a slurry, irradiate the slurry with an electron beam under an oxygen-deficient atmosphere, and obtain filter residue and target metal enrichment solution after solid-liquid separation. The black powder contains at least one metallic element, either nickel or cobalt, wherein the molar ratio of nickel and / or cobalt to ammonium ions in the ammonia solution is not higher than 1:6. The pH of the ammonia solution is 9-11, and the concentration of NH4+ is c(NH4+). + =1~4 mol / L; The oxygen-deficient atmosphere refers to an oxygen content of less than 3%; The conditions for electron beam irradiation are: energy of 1~3MeV and dose of 20~100kGy.

[0008] Electron beam irradiation can enhance e under conditions of pH around 10 and high concentrations of ammonium ions (adjusted by adding ammonium chloride). - The dominant role of aq (hydrated electron) reducing radicals is to reduce cobalt and nickel, converting them into Co. 2+ or Ni 2+ This causes the layered oxide structure to break down, thereby releasing nickel-cobalt-lithium into the liquid phase. For example: LiNi x Co y Mn z O2+e - →xNi 2+ +yCo 2+ +zMn 2+ +Li + +2O 2- The following reaction occurs under conditions of pH around 10: 2NH4OH+MnCl2=Mn(OH)2↓+2NH4Cl; 6NH4OH+NiCl2=Ni(NH3)6Cl2+6H2O; 6NH4OH+CoCl2=Co(NH3)6Cl2+6H2O, This allows impurities such as manganese, iron, and aluminum to be contained in the slag, simplifying the impurity removal process.

[0009] In some embodiments, in step S1, the black powder includes at least one of lithium nickel cobalt manganese oxide, lithium-rich manganese-based oxide, lithium cobalt oxide, lithium nickel cobalt aluminum oxide, or lithium nickel manganese oxide. When the black powder contains both nickel and cobalt, the ratio of the total molar amount of nickel and cobalt to the molar amount of ammonium in the ammonia-alkali solution is less than 1:6.

[0010] In some embodiments, in step S1, the ammonia-alkali solution also contains a free radical conversion agent; The free radical converting agent is selected from at least one of methanol, ethanol, isopropanol, formate, acetate, dimethyl sulfoxide, glycerol, methacrylic acid, or acrylic acid; The concentration of the free radical converter in the ammonia-alkali solution is 1~10 mmol / L.

[0011] When an electron beam irradiates water, the following types of active species are mainly produced: Strongly reducing species: hydrated electrons (e - aq), hydrogen radicals (·H) Strong oxidizing species: hydroxyl radical (·OH) Molecular products: hydrogen (H2), hydrogen peroxide (H2O2).

[0012] •H can reduce nickel, cobalt, and manganese, thereby promoting leaching, while •OH, with its strong oxidizing properties, not only has the opposite effect but also damages graphite. Therefore, it is necessary to increase the •H concentration in the liquid phase while suppressing or utilizing the unfavorable •OH.

[0013] •OH can react with free radical converters through hydrogen abstraction or addition reactions, for example: Isopropanol (hydrogen abstraction reaction): (CH3)2CHOH +·OH →OH(CH3)2C· + H2O, OH(CH3)2C· can perform the following functions: (1) it combines with the dangling bonds or active sites at the graphite defects to achieve “functionalized suturing”, thereby achieving the repair of graphite.

[0014] Acrylic acid (addition reaction): CH2=CH-COOH+·OH →·CH2-C(OH)-COOH, the effect is the same as above.

[0015] Dimethyl sulfoxide (addition reaction): (CH3)2SO + ·OH → (CH3)2S(OH)O·, (CH3)2S(OH)O· → ·CH3+ CH3S(O)OH (the reaction rate is extremely fast).

[0016] CH3 has extremely high reactivity and small size, allowing it to easily diffuse into the interlayer of graphite or into tiny defects, thus repairing the graphite.

[0017] Regarding the dangling key at the graphite defect: In a perfect graphene lattice, each carbon atom is sp... 2 The hybridization forms strong σ bonds with three adjacent carbon atoms, and the remaining p electron forms a delocalized large π bond, making the system very stable.

[0018] When vacancies, edges, or cracks occur, the carbon atom at that location loses one or more neighboring atoms, resulting in unpaired electrons (dangling bonds).

[0019] Free radicals are molecules or atoms containing unpaired electrons and have extremely high reactivity.

[0020] The dangling bonds in graphite provide an unpaired electron cloud, which can react with free radicals through hydrogen abstraction (H-atom transfer) or electron transfer, thereby producing a repair effect.

[0021] In some preferred embodiments, in step S1, the ammonia solution also contains either dimethyl sulfoxide or acrylic acid.

[0022] In some embodiments, step S1 further includes: washing the filter residue with water multiple times, and combining the resulting washing liquid with the target metal enrichment solution.

[0023] In some embodiments, when the black powder is selected from at least one of lithium nickel cobalt manganese oxide, lithium-rich manganese-based oxide, or lithium nickel manganese oxide, step S1 further includes: acid leaching the filter residue, and obtaining graphite residue and manganese-aluminum liquid after solid-liquid separation.

[0024] In some embodiments, step S1 further includes: adjusting the pH of the manganese-aluminum liquid to 4-5 to carry out an iron-aluminum precipitation reaction, and obtaining an iron-aluminum slag and an iron-aluminum precipitate liquid after solid-liquid separation.

[0025] In some embodiments, step S1 further includes: adjusting the pH of the iron-aluminum-removed liquid to 8.5-9, and introducing air to carry out a manganese precipitation reaction, followed by solid-liquid separation to obtain manganese oxygen-containing compounds. 2+ Under these alkaline conditions, it is oxidized by air to form MnO(OH)2 or manganese tetroxide precipitate with extremely low solubility.

[0026] In some embodiments, the leaching method for the battery black powder further includes the following steps: S2: The target metal enrichment solution is heated to carry out a precipitation reaction, and after solid-liquid separation, lithium-rich solution and precipitate are obtained. S3: Dissolve the precipitate with acid, and then perform a copper removal reaction on the resulting acid-dissolved liquid. After solid-liquid separation, a filtrate containing nickel and / or cobalt and a copper-containing precipitate are obtained. S4: Extract and separate the filtrate to obtain nickel salt purified solution and / or cobalt salt purified solution.

[0027] In some embodiments, in step S2, the temperature rise is to heat to 70~90°C.

[0028] In some embodiments, the precipitation reaction is accompanied by the generation of gas, and step S2 further includes: passing the gas generated by the precipitation reaction into a sulfuric acid solution or water. The generated gas is ammonia, which can be used to prepare ammonium chloride or ammonia water, as shown in the following reaction formula: Ni(NH3)6Cl2 + 2NaOH Ni(OH)₂ + 6NH₃ + 2NaCl; Co(NH3)6Cl2 + 2NaOH Co(OH)2 + 6NH3 + 2NaCl; Cu(NH3)4Cl2 + 2NaOH CuO + 4NH3 + 2NaCl + H2O.

[0029] In some embodiments, step S3, the copper removal reaction includes: adding sodium sulfide to the nickel-cobalt-copper liquid and stirring the mixture. Sodium sulfide reacts with copper ions to form copper sulfide precipitate.

[0030] The lithium-rich solution obtained through precipitation reaction can be used to prepare lithium carbonate or lithium hydroxide.

[0031] In some embodiments, step S3, the extraction and separation includes: performing a first extraction using a first extraction system to obtain a first organic phase and a nickel-containing raffinate; performing a first back-extraction on the first organic phase to obtain a cobalt-containing solution; performing a second extraction using a second extraction system on the cobalt-containing solution; performing a second back-extraction and oil removal sequentially on the obtained second organic phase to obtain a cobalt salt purified solution; and performing a third extraction using a third extraction system on the nickel-containing raffinate; performing a third back-extraction and oil removal sequentially on the obtained third organic phase to obtain a nickel salt purified solution. The first extraction system comprises sodium soap P507 (saponification rate of 20%~30%) and sulfonated kerosene diluent, with a volume ratio of sodium soap P507 to sulfonated kerosene of (20~30):(70~80); the second extraction system comprises ammonia soap C272 (saponification rate of 20%~30%) and sulfonated kerosene diluent, with a volume ratio of ammonia soap C272 to sulfonated kerosene of (20~30):(70~80); the third extraction system comprises sodium soap C272 (saponification rate of 20%~30%) and sulfonated kerosene diluent, with a volume ratio of sodium soap C272 to sulfonated kerosene of (20~30):(70~80). The first back-extraction is carried out using dilute sulfuric acid with a hydrogen ion concentration of (3.5~4) mol / L, the second back-extraction is carried out using dilute sulfuric acid with a hydrogen ion concentration of (1.5~2) mol / L, and the third back-extraction is carried out using dilute sulfuric acid with a hydrogen ion concentration of (1.5~2) mol / L.

[0032] In some preferred embodiments, the first organic phase is washed first before the first back-extraction, the second organic phase is washed second before the second back-extraction, and the third organic phase is washed third before the third back-extraction; the washing acid used for the first, second, and third washes is dilute sulfuric acid with a hydrogen ion concentration of (0.3~0.6) mol / L.

[0033] In some preferred embodiments, the first organic phase is subjected to a first anti-iron reaction before the first back-extraction, the second organic phase is subjected to a second anti-iron reaction before the second back-extraction, and the third organic phase is subjected to a third anti-iron reaction before the third back-extraction; the first anti-iron reaction, the second anti-iron reaction, and the third anti-iron reaction are carried out independently using hydrochloric acid with a hydrogen ion concentration of 6±0.2mol / L.

[0034] According to a second aspect of the present invention, the application of the leaching method described in the first aspect of the present invention in the recycling of waste lithium-ion batteries is proposed.

[0035] According to one embodiment of the present invention, at least the following beneficial effects are achieved: This invention employs an electron beam irradiation-assisted alkaline method to extract precious metals from black powder, reducing the use of acids and oxidants, thereby reducing corrosion of the reaction vessel and improving the selective leaching of target metals, thus increasing production efficiency. The recovery rates of nickel, cobalt, and lithium are as high as 99.6%, 99.6%, and 95.9%, respectively; at the same time, graphite is repaired. Attached Figure Description

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a process flow diagram of Embodiment 1 of the present invention. Detailed Implementation

[0037] The following will describe the concept and technical effects of the present invention clearly and completely with reference to the embodiments, so as to fully understand the purpose, features and effects of the present invention, but the present invention is not limited to the scope of the embodiments described.

[0038] Unless otherwise specified, experimental methods in the following examples were performed using conventional methods and conditions. Unless otherwise specified, the raw materials, reagents, or apparatus used in the following examples or comparative examples are all available from conventional commercial sources or can be obtained by existing known methods. The black powder is ternary lithium battery powder, with the following composition:

[0039] Example 1 This embodiment provides a method for leaching battery black powder based on electron beam irradiation-induced free radical redox leaching, including the following steps: (1) Disperse black powder in ammonia-alkali solution to obtain slurry. Irradiate the slurry with electron beam under an atmosphere with an oxygen content of less than 1%. Filter the slurry by pressure, wash the filter residue with water three times, and combine the washing liquid and filtrate to obtain the target metal enrichment solution.

[0040] The pH of the ammonia-alkali solution is 10, and c(NH4)2 is... + The concentration of NH4+ is 2.6 mol / L, and the concentration of dimethyl sulfoxide is 5 mmol / L. The solution is prepared as follows: Prepare a 1 mol / L ammonia solution, then add a 1 mol / L hydrochloric acid solution to adjust the pH to 10, and then add ammonium chloride solid to adjust the concentration of NH4+ in the solution. + =2.6mol / L, and finally add dimethyl sulfoxide according to the concentration of dimethyl sulfoxide.

[0041] Electron beam irradiation conditions: energy 2 MeV, dose 50 kGy. The solid-liquid ratio of black powder to ammonia-alkali solution was set at 1:6, based on the total molar ratio of nickel and cobalt to ammonium.

[0042] (2) Heat the target metal enrichment solution to 80°C and stir to carry out the nickel-cobalt-copper precipitation reaction. Collect the volatile gas and pass it into hydrochloric acid solution until the ammonia content of the gas is less than 1000ppm. After pressure filtration, the filter residue is washed with water multiple times to obtain nickel-cobalt-copper precipitate. Combine the washing liquid and filtrate to obtain lithium-rich solution.

[0043] (3) Add sulfuric acid solution (hydrogen ion concentration of 2 mol / L) to the nickel-cobalt-copper precipitate, stir to dissolve and obtain nickel-cobalt-copper solution; add to the nickel-cobalt-copper solution according to n(Cu 2+ ): n(Na2S) = 1:1.05. Sodium sulfide was added to remove copper. After pressure filtration and washing, nickel-cobalt solution and copper sulfide precipitate were obtained. (4) Add liquid alkali to adjust the pH of the nickel-cobalt solution to 4.8, and then use sodium soap P507 (saponification rate 25%) to extract the nickel-cobalt solution. The diluent is sulfonated kerosene. The volume ratio of sodium soap P507 to sulfonated kerosene is 20:80. The extraction stage is 8 stages, the washing stage is 5 stages, the anti-iron stage is 2 stages (using hydrochloric acid with a hydrogen ion concentration of 6 mol / L), and the back-extraction stage is 5 stages. The washing acid is dilute sulfuric acid (hydrogen ion concentration of 0.4 mol / L), and the back-extraction acid is dilute sulfuric acid (hydrogen ion concentration of 4 mol / L), to obtain nickel-containing raffinate and cobalt-containing solution. Add sulfuric acid to adjust the pH of the cobalt-containing solution to 4, and then use ammonia soap C272 (saponification rate 20%) to extract the cobalt-containing solution. The diluent is sulfonated kerosene. The volume ratio of ammonia soap C272 to sulfonated kerosene is 20:80. The extraction stage is 8 stages, the washing stage is 5 stages, and the back-extraction stage is 5 stages. The process involves two stages of anti-iron extraction (using hydrochloric acid with a hydrogen ion concentration of 6 mol / L), washing with dilute sulfuric acid (hydrogen ion concentration of 0.4 mol / L), and back-extraction with dilute sulfuric acid (hydrogen ion concentration of 2 mol / L) to obtain a cobalt sulfate solution. After oil removal, a purified cobalt sulfate solution is obtained. Liquid alkali is added to adjust the pH of the nickel-containing raffinate to 8. Then, sodium soap C272 (saponification rate of 25%) is used to extract the nickel-containing raffinate. The diluent is sulfonated kerosene, and the volume ratio of sodium soap C272 to sulfonated kerosene is 20:80. The extraction stage consists of 8 stages, the washing stage consists of 5 stages, and the back-extraction stage consists of 5 stages. A second stage of anti-iron extraction (using hydrochloric acid with a hydrogen ion concentration of 6 mol / L), washing with dilute sulfuric acid (hydrogen ion concentration of 0.4 mol / L), and back-extraction with dilute sulfuric acid (hydrogen ion concentration of 2 mol / L) is used to obtain a nickel sulfate solution. After oil removal, a purified nickel sulfate solution is obtained.

[0044] (5) Add sulfuric acid solution (hydrogen ion concentration of 1 mol / L) to the filter residue obtained in step (1) and heat to 60°C for acid dissolution. After filtration, manganese aluminum liquid and graphite slag are obtained. Add alkali to the manganese aluminum liquid to adjust the pH to 6.5~7 to precipitate aluminum and iron. After pressing and washing, iron and aluminum slag and liquid after removing iron and aluminum are obtained. Add alkali to the liquid after removing iron and aluminum to adjust the pH to 8.5~9 and pass air to carry out manganese precipitation reaction. After pressing and washing, manganese oxygen-containing compounds are obtained. Roast the manganese oxygen-containing compounds in air to obtain manganese tetroxide.

[0045] (6) The graphite slag obtained in step (5) is soaked in sulfuric acid solution (hydrogen ion concentration 2 mol / L), stirred for 2.5 h, then filtered, dried at 90 °C to constant weight, and then placed in a muffle furnace, heated to 1000 °C in a nitrogen atmosphere, and kept at that temperature for 2 h to obtain regenerated graphite.

[0046] Example 2 This embodiment provides a method for leaching battery black powder based on electron beam irradiation-induced free radical redox leaching, including the following steps: (1) Disperse black powder in ammonia-alkali solution to obtain slurry. Irradiate the slurry with electron beam under an atmosphere with an oxygen content of less than 0.5%. Filter the slurry, wash the filter residue with water three times, and combine the washing liquid and filtrate to obtain the target metal enrichment solution.

[0047] The black powder composition is the same as in Example 1, and the pH of the ammonia-alkali solution is 11, c(NH4) + The concentration of NH4+ is 4 mol / L, and the concentration of dimethyl sulfoxide is 3 mmol / L. The solution is prepared as follows: Prepare a 1 mol / L ammonia solution, then add 0.5 mol / L hydrochloric acid solution to adjust the pH to 11, and then add ammonium chloride solid to adjust the concentration of NH4+ in the solution. + =4mol / L, and finally add dimethyl sulfoxide according to the concentration of dimethyl sulfoxide.

[0048] Electron beam irradiation conditions: energy 1 MeV, dose 80 kGy. The solid-liquid ratio of black powder to ammonia-alkali solution was set at 1:6, based on the total molar ratio of nickel and cobalt to ammonium.

[0049] Steps (2) to (6) are the same as in Example 1.

[0050] Example 3 The difference from Example 1 is that no radical conversion agent (dimethyl sulfoxide) was added in step (1).

[0051] Comparative Example 1 The difference from Example 1 is that in step (1), the c(NH4) of the ammonia solution... + The concentration of NH4+ is 0.8 mol / L, pH=10, and the concentration of dimethyl sulfoxide is 5 mmol / L. The solution is prepared as follows: Prepare a 1 mol / L ammonia solution, then add a 1 mol / L hydrochloric acid solution to adjust the pH to 10, and then add ammonium chloride solid to adjust the concentration of NH4+ in the solution. + =0.8mol / L, and finally add dimethyl sulfoxide according to the concentration of dimethyl sulfoxide.

[0052] Test case 1. Recovery rate determination In the methods described in the above embodiments, the recovery rates of Ni (Ni content in purified nickel sulfate solution / Ni content in black powder × 100%), Co (Co content in purified cobalt sulfate solution / Co content in black powder × 100%), and Li (Li content in lithium-rich solution / Li content in black powder × 100%) are shown in Table 1. The concentration of metal ions in the liquid was measured by ICP.

[0053] Table 1

[0054] As can be seen, the electron beam irradiation-assisted alkaline leaching method of this invention can efficiently recover Ni, Co, and Li from battery black powder with high selectivity. In Examples 1 and 2, compared to Example 3, the free radical conversion agent dimethyl sulfoxide was added, further improving the recovery rate of valuable metals. In Comparative Example 1, the ammonium ion concentration in the ammonia-alkali solution was low, resulting in a lower recovery rate of nickel and cobalt. This is because ammonium ions can rapidly consume oxidizing ·OH; if the ammonium ion concentration is insufficient, nickel hydroxide and cobalt hydroxide will precipitate, causing losses.

[0055] 2. Performance test of recycled graphite Recycled graphite was prepared into button cells in the following manner, and then the electrochemical performance of the cells was tested.

[0056] Preparation methods include: Electrode preparation: Regenerated graphite, acetylene black and binder (PVDF) were mixed in a mass ratio of 93:5:2, and NMP was added to obtain a slurry. The slurry was coated onto copper foil with a scraper and then dried in an oven at 120°C for 12 hours. The slurry was then pressed, cut and weighed using a punch press to obtain graphite electrode sheets.

[0057] Preparation of button cells: In a glove box under an argon atmosphere (H2O<0.01ppm, O2<0.01ppm), button cells were assembled using CR2025 battery cases. Polypropylene porous membranes were used as separators. The electrolyte solute was 1mol / L LiPF6, and the electrolyte solvents were EC, DEC, and EMC in a volume ratio of 1:1:1. The prepared graphite electrode sheets were placed in the positive electrode case, and high-purity lithium sheets (≥99.9wt%) were placed in the negative electrode case as counter electrodes. The cells were then sealed using a battery sealing machine and tested after standing for 24 hours.

[0058] Electrochemical performance testing: using a multi-channel battery tester (NEWARE CT) The 3008 was tested, with a charging and discharging voltage range of 0.005V to 2.0V. The results are as follows:

[0059] It is evident that this invention, while recovering valuable metals through electron beam irradiation-assisted alkaline leaching, also effectively repairs graphite. The poor performance of the regenerated graphite obtained in Comparative Example 1 is due to the low concentration of ammonium ions in the ammonia-alkali solution used, which failed to effectively consume the oxidizing ·OH radicals, thus damaging the graphite.

[0060] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A method for leaching battery black powder, characterized in that, Includes the following steps: S1: Mix black powder with ammonia-alkali solution to obtain a slurry, irradiate the slurry with an electron beam under an oxygen-deficient atmosphere, and obtain filter residue and target metal enrichment solution after solid-liquid separation. The black powder contains at least one metallic element, either nickel or cobalt, wherein the molar ratio of nickel and / or cobalt to ammonium ions in the ammonia solution is not higher than 1:

6. The pH of the ammonia solution is 9-11, and the concentration of NH4+ is c(NH4+). + =1~4 mol / L; The oxygen-deficient atmosphere refers to an oxygen content of less than 3%; The conditions for electron beam irradiation are: energy of 1~3MeV and dose of 20~100kGy.

2. The leaching method according to claim 1, characterized in that, In step S1, the black powder includes at least one of lithium nickel cobalt manganese oxide, lithium-rich manganese-based oxide, lithium cobalt oxide, lithium nickel cobalt aluminum oxide, or lithium nickel manganese oxide.

3. The leaching method according to claim 1, characterized in that, In step S1, the ammonia-alkali solution also contains a free radical conversion agent; The free radical converting agent is selected from at least one of methanol, ethanol, isopropanol, formate, acetate, dimethyl sulfoxide, glycerol, methacrylic acid, or acrylic acid; The concentration of the free radical converter in the ammonia-alkali solution is 1~10 mmol / L.

4. The leaching method according to claim 1, characterized in that, When the black powder is selected from at least one of lithium nickel cobalt manganese oxide, lithium-rich manganese-based oxide, or lithium nickel manganese oxide, step S1 further includes: acid leaching the filter residue, and obtaining graphite residue and manganese-aluminum liquid after solid-liquid separation.

5. The leaching method according to claim 4, characterized in that, Step S1 further includes: adjusting the pH of the manganese-aluminum liquid to 4-5 to carry out the iron-aluminum precipitation reaction, and obtaining the liquid after iron and aluminum removal and iron-aluminum slag after solid-liquid separation.

6. The leaching method according to claim 5, characterized in that, Step S1 further includes: adjusting the pH of the liquid after removing iron and aluminum to 8.5~9, and introducing air to carry out a manganese precipitation reaction, and obtaining manganese oxygenated compounds after solid-liquid separation.

7. The leaching method according to claim 1, characterized in that, It also includes the following steps: S2: The target metal enrichment solution is heated to carry out a precipitation reaction, and after solid-liquid separation, lithium-rich solution and precipitate are obtained. S3: Dissolve the precipitate with acid, and then perform a copper removal reaction on the resulting acid-dissolved liquid. After solid-liquid separation, a filtrate containing nickel and / or cobalt and a copper-containing precipitate are obtained. S4: Extract and separate the filtrate to obtain nickel salt purified solution and / or cobalt salt purified solution.

8. The leaching method according to claim 7, characterized in that, In step S3, the copper removal reaction includes adding sodium sulfide to the acid-dissolved solution and stirring the mixture.

9. The leaching method according to claim 7, characterized in that, In step S2, the temperature increase is to heat to 70~90℃.

10. The application of the leaching method according to any one of claims 1-9 in the recycling of waste lithium-ion batteries.

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