Resource recycling method for nickel-cobalt-manganese ternary cathode materials

Abstract

The present invention provides a method for resource recovery of nickel-cobalt-manganese ternary cathode materials, which relates to the technical field of recycling of waste lithium-ion battery cathode materials. The method comprises the following steps: crushing the nickel-cobalt-manganese ternary cathode materials, immersing them in inorganic acid for dissolution to obtain a dissolution solution, filtering the dissolution solution, and taking the filtrate to obtain an acidolysis solution; performing a first-stage adsorption treatment on the acidolysis solution to obtain a first negative carrier loaded with nickel and a first filtrate, then performing a second-stage adsorption treatment on the first filtrate to obtain a second negative carrier loaded with manganese and a second filtrate, and then performing a third-stage adsorption treatment on the second filtrate to obtain a third negative carrier loaded with cobalt and a third filtrate; respectively performing elution treatment on the first negative carrier, the second negative carrier, and the third negative carrier to obtain a first eluate, a second eluate, and a third eluate correspondingly, and then treating each eluate to obtain nickel-containing precipitates, manganese dioxide precipitates, and cobalt-containing precipitates, and the recovery rates of nickel, manganese, and cobalt are all > 85%.

Description

Technical Field

[0001] The invention relates to the technical field of recycling waste lithium-ion battery positive electrode materials, and in particular to a method for recycling nickel-cobalt-manganese ternary positive electrode materials. Background Art

[0002] Nickel-cobalt-manganese ternary materials are a new type of lithium-ion battery cathode material developed in recent years. They have important advantages such as high capacity, good cycle stability, and moderate cost. Since this type of material can effectively overcome the problems of high cost of lithium cobalt oxide materials, low stability of lithium manganese oxide materials, and low capacity of lithium iron phosphate, it has been successfully applied in industries that require batteries such as new energy vehicles, and the scale of application has been rapidly developed. However, nickel, cobalt, and manganese elements are mainly distributed in the form of mineral resources in nature. Faced with the huge demand of current new energy vehicles and other industries, nickel, cobalt, and manganese resources are very limited. However, the content of valuable metals such as nickel, cobalt, and manganese in the nickel-cobalt-manganese cathode materials of waste ternary lithium-ion batteries is relatively high, far higher than that of natural ores. Therefore, faced with the huge demand of current new energy vehicles and other industries, it is necessary to recycle and reuse nickel-cobalt-manganese ternary cathode materials.

[0003] At present, the main method used to recycle waste nickel-cobalt-manganese (NCM) ternary lithium-ion battery positive electrode materials is pyrometallurgy. The pyrometallurgical treatment method mainly uses high temperature to treat waste positive electrode materials, and purifies the valuable metals through physical and chemical transformation, converting them into metal elements and metal oxides, so as to achieve the purpose of extracting and purifying valuable metals; however, the pyrometallurgical treatment method has the disadvantages of high energy consumption and low recovery rate of valuable metals such as nickel, cobalt, and manganese due to loss in the slag. Summary of the invention

[0004] 1. Technical issues to be solved

[0005] In view of the shortcomings of the prior art, the present invention provides a method for resource recovery of nickel-cobalt-manganese ternary positive electrode materials, which solves the technical problems of high energy consumption of pyrometallurgical treatment methods and low recovery rate of valuable metals such as nickel, cobalt and manganese.

[0006] (II) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] In one aspect, the present invention provides a method for resource utilization of nickel-cobalt-manganese ternary positive electrode materials, comprising the following steps:

[0009] S1. Preparation of acid solution

[0010] Crush the nickel-cobalt-manganese ternary cathode material, then immerse it in an inorganic acid to dissolve and obtain a dissolution solution. Filter the dissolution solution and take the filtrate to obtain an acidolysis solution; the inorganic acid is selected from any one of sulfuric acid, hydrochloric acid, and nitric acid, and an appropriate amount of H2O2 can also be added to the inorganic acid to improve the dissolution ability of the nickel-cobalt-manganese ternary cathode material.

[0011] S2. Perform an adsorption treatment on the acidolysis solution

[0012] Perform a first-stage adsorption treatment on the acidolysis solution to obtain a first negative carrier loaded with nickel and a first filtrate, then perform a second-stage adsorption treatment on the first filtrate to obtain a second negative carrier loaded with manganese and a second filtrate, and then perform a third-stage adsorption treatment on the second filtrate to obtain a third negative carrier loaded with cobalt and a third filtrate;

[0013] The adsorption medium for the first-stage adsorption treatment is a first biochar material, and the first biochar material is obtained by modifying the biochar obtained by the anaerobic pyrolysis of a first carbon-containing organic matter at 400-900 °C;

[0014] The adsorption medium for the second-stage adsorption treatment is a second biochar material, and the second biochar material is obtained by modifying the biochar obtained by the anaerobic pyrolysis of a second carbon-containing organic matter at 400-900 °C;

[0015] The adsorption medium for the third-stage adsorption treatment is a third biochar material, and the third biochar material is obtained by modifying the biochar obtained by the anaerobic pyrolysis of a third carbon-containing organic matter at 400-900 °C;

[0016] S3. Elute

[0017] Perform elution treatments on the first negative carrier, the second negative carrier, and the third negative carrier respectively to obtain a first eluate containing nickel, a second eluate containing manganese, and a third eluate containing cobalt;

[0018] S4. Precipitate

[0019] Adjust the pH of the first eluate to 10 to obtain nickel hydroxide precipitate;

[0020] Add a sulfate to the second eluate to obtain manganese dioxide precipitate;

[0021] Adjust the pH of the third eluate to 10 to obtain cobalt hydroxide precipitate.

[0022] Add sodium carbonate to the third filtrate to obtain lithium carbonate precipitate.

[0023] Preferably, the first carbon-containing organic matter is selected from at least one of peanut shells and reed straws. The biochar obtained by anaerobic pyrolysis of at least one of peanut shells and reed straws is acid-washed and modified to obtain a first biochar material;

[0024] The second carbon-containing organic matter is selected from at least one of mangosteen shells and buckwheat husks. The biochar obtained by anaerobic pyrolysis of at least one of mangosteen shells and buckwheat husks is acid-washed and modified to obtain a second biochar material;

[0025] The third carbon-containing organic matter is selected from at least one of rice straws and pomelo peels. The biochar obtained by anaerobic pyrolysis of at least one of rice straws and pomelo peels is acid-washed and modified to obtain a third biochar material.

[0026] Preferably, the acid used for the acid-washing modification includes inorganic acid or organic acid. The inorganic acid is selected from any one of sulfuric acid, hydrochloric acid, and nitric acid. The organic acid is selected from any one of citric acid, oxalic acid, and formic acid. The acid used for the acid-washing modification is filtered and recycled for dissolving the nickel-cobalt-manganese ternary cathode material in S1;

[0027] Preferably, the concentration of the organic acid or inorganic acid is 0.5 - 1 mol / L.

[0028] Preferably, the specific surface area of the first biochar material, the second biochar material, and the third biochar material is 200 - 400 m 2 / g.

[0029] Preferably, in the first-stage adsorption treatment, the liquid-solid ratio of the acidolysis solution to the first biochar material is 1000 ml : (1 - 50) g, and the adsorption time is 10 - 60 min;

[0030] In the second-stage adsorption treatment, the liquid-solid ratio of the first filtrate to the second biochar material is 1000 ml : (1 - 50) g, and the adsorption time is 10 - 60 min;

[0031] In the third-stage adsorption treatment, the liquid-solid ratio of the second filtrate to the third biochar material is 1000 ml : (1 - 50) g, and the adsorption time is 10 - 60 min.

[0032] Preferably, in S2, the temperature of the acidolysis solution is 25°C to 50°C, and the pH value is 5.5 to 7.0.

[0033] Preferably, in S1, an alkali solution is further added to the acidolysis solution to adjust the pH value of the acidolysis solution to 4.0 - 4.5 to remove impurity ions and hydroxide ions.

[0034] Preferably, in S3, an acidic solution or an alkaline solution is selected for the elution treatment.

[0035] Preferably, the chemical general formula of the nickel-cobalt-manganese ternary cathode material is LiNi x Co y Mn 1-x-y O2, where x + y ≤ 1.

[0036] (III) Beneficial Effects

[0037] The present invention provides a method for the resource recovery of nickel-cobalt-manganese ternary cathode materials. Compared with the prior art, it has the following beneficial effects:

[0038] The method for the resource recovery of nickel-cobalt-manganese ternary cathode materials includes performing a first-stage adsorption treatment on the acidolysis solution using a first biochar material as the adsorption medium to obtain a first negative carrier loaded with nickel and a first filtrate, then performing a second-stage adsorption treatment on the first filtrate using a second biochar material as the adsorption medium to obtain a second negative carrier loaded with manganese and a second filtrate, and then performing a third-stage adsorption treatment on the second filtrate using a third biochar material as the adsorption medium to obtain a third negative carrier loaded with cobalt and a third filtrate; wherein the first biochar material is biochar obtained by anaerobic pyrolysis of at least one of peanut shells and reed straws at 400 - 900 °C and then acid-washed and modified, and has a preferential adsorption characteristic for nickel; the second biochar material is biochar obtained by anaerobic pyrolysis of at least one of mangosteen shells and buckwheat husks at 400 - 900 °C and then acid-washed and modified, and has a preferential adsorption characteristic for manganese; the third biochar material is biochar obtained by anaerobic pyrolysis of at least one of rice straws and pomelo peels at 400 - 900 °C and then acid-washed and modified, and has a preferential adsorption characteristic for cobalt; the recovery method of the present application utilizes the preferential adsorption characteristics of the first biochar material for nickel, the preferential adsorption characteristics of the second biochar material for manganese, and the preferential adsorption characteristics of the third biochar material for cobalt to perform three-stage adsorption treatment on the acidolysis solution of the nickel-cobalt-manganese ternary cathode material waste, so that the recovery rates of nickel, manganese, and cobalt are all > 85%. Specific Embodiments

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0040] To better understand the above technical solutions, the above technical solutions will be described in detail below in combination with specific embodiments.

[0041] Example 1

[0042] This example provides a method for the resource recovery of nickel-cobalt-manganese ternary cathode material waste, including the following steps:

[0043] Preparation of biochar materials:

[0044] Peanut shells are pyrolyzed at 400 °C under a nitrogen atmosphere to obtain biochar, which is then soaked in hydrochloric acid and dried after washing to obtain the first biochar material;

[0045] Buckwheat husks are pyrolyzed at 400 °C under a nitrogen atmosphere to obtain biochar, which is then soaked in hydrochloric acid and dried after washing to obtain the second biochar material;

[0046] Rice straw is pyrolyzed at 400 °C under a nitrogen atmosphere to obtain biochar, which is then soaked in hydrochloric acid and dried after washing to obtain the third biochar material;

[0047] The specific surface areas of the first biochar material, the second biochar material, and the third biochar material are 200 m 2 / g.

[0048] Preparation of acidolysis solution:

[0049] A certain waste nickel-cobalt-manganese ternary material is crushed to a particle size D50 ≤ 4 μm, and then immersed in sufficient hydrochloric acid to dissolve to obtain a dissolution solution. The dissolution solution is filtered, and the filtrate is taken as the acidolysis solution; sodium hydroxide solution is added to the acidolysis solution to adjust its pH value to 4.0 - 4.5, and the impurity ions in the acidolysis solution are combined with hydroxide ions to form precipitates for impurity removal. Then, the contents of lithium, nickel, cobalt, and manganese in the acidolysis solution are measured as follows: Li 0.85 mg / l, Ni 1.63 mg / l, Co 0.24 mg / l, Mn 0.44 mg / l;

[0050] Perform three-stage adsorption treatment on the acidolysis solution

[0051] Adjust the pH value of the acidolysis solution to 5.5, heat it to 25 °C, and then immerse it in an adsorption stirring tank containing the first biochar material. The liquid-solid ratio of the acidolysis solution to the first biochar material is 1000 ml:1 g, and stir and adsorb for 10 min to obtain the first negative carrier loaded with nickel and the first filtrate;

[0052] Immerse the first filtrate in an adsorption stirring tank containing the second biochar material. The liquid-solid ratio of the first filtrate to the second biochar material is 1000 ml:1 g, and stir and adsorb for 10 min to obtain the second negative carrier loaded with manganese and the second filtrate;

[0053] The second filtrate is immersed in an adsorption stirring tank containing a third biochar material. The liquid-solid ratio of the second filtrate to the third biochar material is 1000 ml:1 g, and stirring adsorption is carried out for 10 minutes to obtain a third carrier loaded with cobalt and a third filtrate. ICP (Inductively Coupled Plasma Spectrometer) is used for testing, and the contents of nickel, cobalt, and manganese in the third filtrate are measured as follows: Ni 0.06 mg / l, Co 0.02 mg / l, and Mn 0.01 mg / l; the recovery rates of nickel, cobalt, and manganese are calculated to be 96.3%, 91.7%, and 97.7% respectively.

[0054] Elution:

[0055] The first carrier, the second carrier, and the third carrier are respectively subjected to elution treatment with 1 mol / L dilute hydrochloric acid. After elution, a first eluate containing nickel, a second eluate containing manganese, and a third eluate containing cobalt are obtained correspondingly. After elution, the first carrier, the second carrier, and the third carrier are respectively obtained as the first biochar material, the second biochar material, and the third biochar material, which are reused after cleaning and drying;

[0056] S4. Precipitation

[0057] Sodium hydroxide is added dropwise to the first eluate to adjust the pH to 10 to obtain nickel hydroxide precipitate containing nickel.

[0058] Sodium sulfate is added to the second eluate to obtain manganese dioxide;

[0059] Potassium hydroxide solution is added dropwise to the third eluate to adjust the pH to 10 to obtain cobalt hydroxide precipitate containing cobalt.

[0060] Sodium carbonate is added to the third filtrate to obtain lithium carbonate precipitate, and the lithium carbonate precipitate is removed by filtration to obtain a fourth filtrate.

[0061] The recovery rates of nickel, cobalt, and manganese are calculated according to the following formula:

[0062] Recovery rate of nickel = (content of nickel in the acidolysis solution - content of nickel in the third filtrate) / content of nickel in the acidolysis solution;

[0063] Recovery rate of cobalt = (content of cobalt in the acidolysis solution - content of cobalt in the third filtrate) / content of cobalt in the acidolysis solution;

[0064] Recovery rate of manganese = (content of manganese in the acidolysis solution - content of manganese in the third filtrate) / content of manganese in the acidolysis solution.

[0065] Example 2

[0066] This example provides a method for resource recovery of nickel-cobalt-manganese ternary cathode material waste, including the following steps:

[0067] The biochar used is selected from the regenerated biochar after elution in Example 1.

[0068] Preparation of acid hydrolysis solution:

[0069] Crush a certain waste nickel-cobalt-manganese ternary material with a particle size D50 ≤ 3 μm, then immerse it in sufficient hydrochloric acid to dissolve and obtain a dissolution solution. Filter the dissolution solution and take the filtrate to obtain the acid hydrolysis solution. Add potassium hydroxide solution to the acid hydrolysis solution to adjust its pH value to 4.0 - 4.5, and combine the impurity ions in the acid hydrolysis solution with hydroxide ions to form precipitates for impurity removal. Then, measure the contents of lithium, nickel, cobalt, and manganese in the acid hydrolysis solution, which are respectively: Li 0.76 mg / l, Ni 1.33 mg / l, Co 0.2 mg / l, and Mn 0.34 mg / l;

[0070] Perform three-stage adsorption treatment on the acid hydrolysis solution

[0071] Adjust the pH value of the acid hydrolysis solution to 6.0, heat it to 40 °C, and then immerse it in an adsorption column containing the first biochar material. The liquid-solid ratio of the acid hydrolysis solution to the first biochar material is 1000 ml:10 g, stir and adsorb for 40 min to obtain the first negative carrier loaded with nickel and the first filtrate;

[0072] Immerse the first filtrate in an adsorption column containing the second biochar material. The liquid-solid ratio of the first filtrate to the second biochar material is 1000 ml:10 g, stir and adsorb for 40 min to obtain the second negative carrier loaded with manganese and the second filtrate;

[0073] Immerse the second filtrate in an adsorption column containing the third biochar material. The liquid-solid ratio of the second filtrate to the third biochar material is 1000 ml:10 g, stir and adsorb for 40 minutes to obtain the third negative carrier loaded with cobalt and the third filtrate. Measure the contents of nickel, cobalt, and manganese in the third filtrate, which are respectively: Ni 0.07 mg / l, Co 0.03 mg / l, and Mn 0.03 mg / l. After calculation, the recovery rate of nickel is 94.7%, the recovery rate of cobalt is 85.0%, and the recovery rate of manganese is 91.2%;

[0074] Elution:

[0075] Perform elution treatment on the first negative carrier, the second negative carrier, and the third negative carrier with dilute hydrochloric acid respectively. After elution, obtain the first eluate containing nickel, the second eluate containing manganese, and the third eluate containing cobalt. After elution, the first negative carrier, the second negative carrier, and the third negative carrier respectively obtain the first biochar material, the second biochar material, and the third biochar material. After cleaning and drying, they are reused;

[0076] S4. Precipitation

[0077] Dropwise add ammonia water to the first eluate to adjust the pH to 10 to obtain nickel hydroxide precipitate containing nickel;

[0078] Sodium sulfate is added to the second eluent to obtain manganese dioxide;

[0079] The pH of the third eluent is adjusted to 10 to obtain cobalt hydroxide precipitate containing cobalt;

[0080] Example 3

[0081] This example provides a method for resource recovery of nickel-cobalt-manganese ternary cathode material waste, including the following steps:

[0082] Preparation of biochar materials:

[0083] Peanut shells are pyrolyzed at 900 °C under a nitrogen atmosphere to obtain biochar, which is then soaked in hydrochloric acid, washed and dried to obtain the first biochar material;

[0084] Mangosteen shells are pyrolyzed at 900 °C under a nitrogen atmosphere to obtain biochar, which is then soaked in hydrochloric acid, washed and dried to obtain the second biochar material;

[0085] Rice straw is pyrolyzed at 900 °C under a nitrogen atmosphere to obtain biochar, which is then soaked in hydrochloric acid, washed and dried to obtain the third biochar material;

[0086] The specific surface areas of the first biochar material, the second biochar material, and the third biochar material are 400 m 2 / g.

[0087] Preparation of acidolysis solution:

[0088] A certain waste nickel-cobalt-manganese ternary material is crushed to a particle size D50 ≤ 3 μm, and then immersed in sufficient hydrochloric acid to dissolve to obtain a dissolution solution. The dissolution solution is filtered, and the filtrate is taken as the acidolysis solution; ammonia water is added to the acidolysis solution to adjust its pH value to 4.0 - 4.5, and the impurity ions in the acidolysis solution are combined with hydroxide ions to form precipitates for impurity removal. Then, the contents of lithium, nickel, cobalt, and manganese in the acidolysis solution are measured as follows: Li 0.83 mg / l, Ni 1.27 mg / l, Co 0.28 mg / l, Mn 0.37 mg / l;

[0089] Perform three-stage adsorption treatment on the acidolysis solution

[0090] The pH value of the acidolysis solution is adjusted to 7.0, heated to 50 °C, and then immersed in an adsorption stirring tank containing the first biochar material. The liquid-solid ratio of the acidolysis solution to the first biochar material is 1000 ml:50 g, and stirred and adsorbed for 60 min to obtain the first negative carrier loaded with nickel and the first filtrate;

[0091] The first filtrate is immersed in an adsorption stirring tank containing the second biochar material. The liquid-solid ratio of the first filtrate to the second biochar material is 1000 ml:50 g, and stirred and adsorbed for 60 min to obtain the second negative carrier loaded with manganese and the second filtrate;

[0092] The second filtrate is immersed in an adsorption stirring tank containing a third biochar material. The liquid-solid ratio of the second filtrate to the third biochar material is 1000 ml:50 g. Stir and adsorb for 60 minutes to obtain a third carrier loaded with cobalt and a third filtrate. The measured contents of nickel, cobalt, and manganese in the third filtrate are: Ni 0.03 mg / l, Co 0.008 mg / l, and Mn 0.015 mg / l. After calculation, the recovery rate of nickel is 97.6%, the recovery rate of cobalt is 97.1%, and the recovery rate of manganese is 95.9%.

[0093] Elution:

[0094] The first carrier, the second carrier, and the third carrier are respectively eluted with 0.5 mol / L dilute hydrochloric acid. After elution, a first eluate containing nickel, a second eluate containing manganese, and a third eluate containing cobalt are obtained correspondingly. After elution, the first carrier, the second carrier, and the third carrier are respectively obtained as the first biochar material, the second biochar material, and the third biochar material. After cleaning and drying, they are reused.

[0095] S4. Precipitation

[0096] Adjust the pH of the first eluate to 10 to obtain nickel hydroxide precipitate containing nickel.

[0097] Sodium sulfate is added to the second eluate to obtain manganese dioxide.

[0098] Adjust the pH of the third eluate to 10 to obtain cobalt hydroxide precipitate containing cobalt.

[0099] Comparative Example 1

[0100] The difference between this comparative example and Example 1 is that the third-stage adsorption treatment step is omitted, and the acidolysis solution is only subjected to the first-stage adsorption treatment and the second-stage adsorption treatment, and the others are the same as in Example 1. The second filtrate is tested. The contents of nickel, cobalt, and manganese in the second filtrate are: Ni 0.07 mg / l, Co 0.23 mg / l, and Mn 0.04 mg / l. The calculated recovery rate of nickel is 95.7%, the recovery rate of cobalt is 4.2%, and the recovery rate of manganese is 90.9%.

[0101] Comparative Example 2

[0102] The difference between this comparative example and Example 1 is that the second-stage adsorption treatment step is omitted, and the acidolysis solution is only subjected to the first-stage adsorption treatment and the third-stage adsorption treatment, and the others are the same as in Example 1. The third filtrate is tested. The contents of nickel, cobalt, and manganese in the third filtrate are: Ni 0.05 mg / l, Co 0.03 mg / l, and Mn 0.43 mg / l. The calculated recovery rate of nickel is 96.9%, the recovery rate of cobalt is 87.5%, and the recovery rate of manganese is 2.3%.

[0103] Comparative Example 3

[0104] The difference between this comparative example and Example 1 is that the first-stage adsorption treatment step is omitted, and the acid hydrolysis solution is only subjected to the second-stage adsorption treatment and the third-stage adsorption treatment, and the others are the same as in Example 1. The third filtrate was tested, and the nickel, cobalt, and manganese contents in the third filtrate were: Ni 1.60 mg / l, Co 0.03 mg / l, and Mn 0.02 mg / l; the recovery rate of nickel was calculated to be 1.8%, the recovery rate of cobalt was 87.5%, and the recovery rate of manganese was 95.5%.

[0105] Comparative Example 4

[0106] The difference between this comparative example and Example 1 is that the adsorption treatment process is different. Specifically, the first biochar material, the second biochar material, and the third biochar material are first mixed evenly and placed in an adsorption stirring tank, and then the acid hydrolysis solution is immersed in the adsorption stirring tank containing the first biochar material, the second biochar material, and the third biochar material for adsorption treatment to replace the three-stage adsorption treatment method, and the others are the same as in Example 1. The adsorbed filtrate was tested, and the nickel, cobalt, and manganese contents in the filtrate were: Ni 1.50 mg / l, Co 0.19 mg / l, and Mn 0.30 mg / l; the recovery rate of nickel was 20.2%, the recovery rate of cobalt was 20.8%, and the recovery rate of manganese was 31.8%.

[0107] In summary, compared with the prior art, the following beneficial effects are achieved:

[0108] 1. A method for resource recovery of nickel-cobalt-manganese ternary cathode materials includes performing a first-stage adsorption treatment on an acidolysis solution with a first biochar material as an adsorption medium to obtain a first negative carrier loaded with nickel and a first filtrate, then performing a second-stage adsorption treatment on the first filtrate with a second biochar material as an adsorption medium to obtain a second negative carrier loaded with manganese and a second filtrate, and then performing a third-stage adsorption treatment on the second filtrate with a third biochar material as an adsorption medium to obtain a third negative carrier loaded with cobalt and a third filtrate. The first biochar material is obtained by acid washing modification of biochar obtained by anaerobic pyrolysis of at least one of peanut shells and reed straws at 400-900 °C, and has a preferential adsorption characteristic for nickel. The second biochar material is obtained by acid washing modification of biochar obtained by anaerobic pyrolysis of at least one of mangosteen shells and buckwheat husks at 400-900 °C, and has a preferential adsorption characteristic for manganese. The third biochar material is obtained by acid washing modification of biochar obtained by anaerobic pyrolysis of at least one of rice straws and pomelo peels at 400-900 °C, and has a specific adsorption characteristic for cobalt. The recovery method of the present application utilizes the preferential adsorption characteristics of the first biochar material for nickel, the preferential adsorption characteristics of the second biochar material for manganese, and the preferential adsorption characteristics of the third biochar material for cobalt to perform a three-stage adsorption treatment on the acidolysis solution of the nickel-cobalt-manganese ternary cathode material waste, so that the recovery rates of nickel, cobalt, and manganese are all greater than 85%.

[0109] 2. The nickel, cobalt, and manganese recovery method of the present application has a simple recovery process, low cost, good environmental protection, high efficiency, stronger industrial operability, and can also respectively obtain nickel, cobalt, and manganese metal salts that can be directly used in industry in a targeted manner.

[0110] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0111] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Where the present invention is not described in detail, it is the well-known technology of those skilled in the art.

Claims

1. A method for recycling nickel-cobalt-manganese ternary positive electrode materials, characterized in that: The steps include: S1. Preparation of acid solution The nickel-cobalt-manganese ternary positive electrode material is crushed, immersed in an inorganic acid to dissolve to obtain a solution, the solution is filtered, and the filtrate is taken to obtain an acid hydrolysis solution; an appropriate amount of hydrogen peroxide is added to the inorganic acid; S2. Adsorption treatment of acid solution Using a first biochar material as an adsorption medium, the acid hydrolyzed liquid is subjected to a first-stage adsorption treatment to obtain a first support body and a first filtrate loaded with nickel; then using a second biochar material as an adsorption medium, the first filtrate is subjected to a second-stage adsorption treatment to obtain a second support body and a second filtrate loaded with manganese; and then using a third biochar material as an adsorption medium, the second filtrate is subjected to a third-stage adsorption treatment to obtain a third support body and a third filtrate loaded with cobalt; The first biochar material, the second biochar material, and the third biochar material are respectively obtained by modifying the biochar obtained by anaerobic pyrolysis of the first carbon-containing organic matter, the second carbon-containing organic matter, and the third carbon-containing organic matter at 400-900° C. S3, elution The first support body, the second support body and the third support body are subjected to elution treatment respectively, and a first eluent containing nickel, a second eluent containing manganese and a third eluent containing cobalt are obtained accordingly; S4. Precipitation adjusting the pH of the first eluent to obtain a nickel-containing precipitate; adding persulfate to the second eluent to obtain a manganese dioxide precipitate; adjusting the pH of the third eluent to obtain a cobalt-containing precipitate; The first carbon-containing organic matter is selected from at least one of peanut shells and reed straws, and the biochar obtained by anaerobic pyrolysis of at least one of the peanut shells and reed straws is acid-washed and modified to obtain the first biochar material; The second carbon-containing organic matter is selected from at least one of mangosteen shells and buckwheat shells, and the biochar obtained by anaerobic pyrolysis of at least one of mangosteen shells and buckwheat shells is acid-washed and modified to obtain a second biochar material; The third carbon-containing organic matter is selected from at least one of rice straw and grapefruit peel. The biochar obtained by anaerobic pyrolysis of at least one of rice straw and grapefruit peel is modified by acid washing to obtain the third biochar material.

2. The recycling method according to claim 1, characterized in that: The acid used for the pickling modification includes an inorganic acid or an organic acid. The inorganic acid is selected from any one of sulfuric acid, hydrochloric acid, and nitric acid. The organic acid is selected from any one of citric acid, oxalic acid, and formic acid.

3. The recycling method according to claim 2, characterized in that: The concentration of the organic acid or inorganic acid is 0.5-1 mol / L.

4. The recycling method according to claim 1, characterized in that: The specific surface area of ​​the first biochar material, the second biochar material and the third biochar material is 200-400m 2 / g.

5. The recycling method according to claim 1, characterized in that: In the first-stage adsorption treatment, the liquid-solid ratio of the acid hydrolyzate to the first biochar material is 1000ml:(1-50)g, and the adsorption time is 10-60min; in the second-stage adsorption treatment, the liquid-solid ratio of the first filtrate to the second biochar material is 1000ml:(1-50)g, and the adsorption time is 10-60min; in the third-stage adsorption treatment, the liquid-solid ratio of the second filtrate to the third biochar material is 1000ml:(1-50)g, and the adsorption time is 10-60min.

6. The recycling method according to claim 1, characterized in that: In S2, the temperature of the acid hydrolysis solution is 25°C to 50°C, and the pH value is 5.5 to 7.

0.

7. The recycling method according to claim 1, characterized in that: The step S1 further includes adding alkaline solution to the acid hydrolysis solution to adjust the pH value of the acid hydrolysis solution to 4.0-4.5 to remove impurity ions and hydroxide ions.

8. The recycling method according to claim 1, characterized in that: In S3, an acidic solution is selected for elution treatment.

9. The recycling method according to claim 1, characterized in that: The general chemical formula of the nickel-cobalt-manganese ternary positive electrode material is LiNi x Co y Mn 1-x-y O2, where x+y<1; The recovery method further comprises adding sodium carbonate to the third filtrate to obtain a lithium carbonate precipitate.