Method for graded recovery of valuable metals from waste ternary lithium ion batteries

Abstract

The invention provides a method for graded recovery of valuable metals from waste ternary lithium ion batteries. The method specifically comprises the following steps: S1) pretreating the waste ternary lithium ion batteries; s2) mixing the pretreated waste ternary cell powder with biomass, and carrying out carbon thermal reduction roasting to obtain roasted solid powder; s3) mixing the roasted solid powder with an acid solution, and heating for acid leaching to obtain a leaching solution and insoluble slag; s4) adjusting the pH value of the leachate, and reacting the leachate with bicarbonate to obtain a manganese carbonate solid phase and filtrate; and S5) adjusting the pH value of the filtrate, and then carrying out carbonization and lithium precipitation to obtain lithium carbonate. According to the method, biomass which is low in cost and easy to obtain is used as a carbon source, a reducing atmosphere generated by carbonization and pyrolysis of the biomass is coupled with carbon thermal reduction roasting, so that valuable metals in the waste ternary lithium ion battery are reduced to be in a low valence state, and then specific acid leaching is combined to carry out gradient separation and recovery on lithium, nickel, cobalt and manganese; and clean, efficient extraction and comprehensive utilization of the waste ternary lithium ion battery can be realized.

Description

Technical Field

[0001] The invention relates to the technical fields of chemical metallurgy and resource recycling, and in particular to a method for recycling valuable metals from waste ternary lithium-ion batteries by classification. Background Art

[0002] Lithium-ion batteries have the advantages of high specific energy, long service life and good safety, and are widely used in new energy electric vehicles and various electronic products. As the electric vehicle industry continues to increase its requirements for battery quality and quantity, lithium-ion batteries, as energy storage and power electrochemical energy storage devices, have become one of the current research hotspots, and their number is also increasing year by year.

[0003] Waste ternary lithium battery electrode materials have outstanding resource attributes, and Li, Ni, and Co in the electrode materials all have high metal value. Therefore, the recycling of waste ternary lithium-ion battery resources has important economic and environmental benefits. Waste ternary lithium-ion batteries usually contain 5%~20% cobalt, 5%~10% nickel, and 5%~7% lithium. These metal elements all have high recycling and reuse value.

[0004] With the increasing demand for power equipment, the recycling value of valuable metals in waste ternary lithium-ion batteries is considerable. Among the methods for recovering valuable metals in waste ternary lithium-ion batteries, the traditional pyrometallurgical roasting has large lithium losses, high energy consumption, and serious pollution. For hydrometallurgy, metals are leached in the form of ions and then selectively recovered. However, Ni, Co, and Mn have similar chemical and physical properties, and it is challenging to recover high-purity valuable metals through hydrometallurgy.

[0005] Therefore, it is of great significance to provide a method for recovering valuable metals in waste ternary lithium-ion batteries to achieve the separate recovery of nickel, cobalt, manganese and lithium. Summary of the invention

[0006] The technical problem solved by the present invention is to provide a method for graded recovery of valuable metals from waste ternary lithium-ion batteries. The method provided in the present application can achieve preferential leaching of lithium and manganese, while achieving the recycling of nickel and cobalt.

[0007] In view of this, the present application provides a method for recycling valuable metals from waste ternary lithium-ion batteries by graded method, comprising the following steps:

[0008] S1) pre-treating the waste ternary lithium-ion batteries to obtain waste ternary battery powder;

[0009] S2) mixing the waste ternary battery core powder and a biomass carbon source and performing carbon thermal reduction roasting to obtain a roasted solid powder;

[0010] S3) mixing the roasted solid powder with an acid solution, acid leaching, and then performing solid-liquid separation to obtain a leachate and an insoluble slag;

[0011] S4) mixing the leaching solution and alkali solution to adjust the pH, reacting with bicarbonate, and filtering to obtain a manganese carbonate solid phase and a filtrate;

[0012] S5) The filtrate is mixed with an alkaline solution to adjust the pH, and then carbonization is performed to precipitate lithium to obtain lithium carbonate.

[0013] Preferably, in step S1), the pre-processing is specifically:

[0014] The waste ternary lithium-ion batteries are first subjected to discharge and crushing treatment, and then sieved, magnetically separated and air-separated in sequence to obtain waste ternary battery core powder;

[0015] The particle size of the waste ternary battery core powder is 50-200 mesh.

[0016] Preferably, in step S2), the biomass carbon source includes one or more of chitosan, chitin and starch, and the mass ratio of the biomass carbon source to the waste ternary battery core powder is 1: (0.01~3).

[0017] Preferably, in step S2), the temperature of the carbon thermal reduction calcination is 300-1000° C., and the time is 10 min-5 h.

[0018] Preferably, in step S3), the acid solution comprises one of acetic acid, sulfuric acid, formic acid and hydrochloric acid, and the concentration of the acid solution is 0.1-3M.

[0019] Preferably, in step S3), the acid leaching temperature is 25-90° C., and the time is 2 min-6 h.

[0020] Preferably, in step S4), the alkali solution includes one or both of ammonia water and sodium hydroxide, the concentration of the alkali solution is 0.01-10M, and the pH is adjusted to 3.0-10.0.

[0021] Preferably, in step S4), the bicarbonate includes one or more of NaHCO3, KHCO3 and NH3HCO3; the molar amount of the bicarbonate added is 0.5 to 3 times the molar concentration of lithium ions in the leachate.

[0022] Preferably, in step S5), the alkali solution includes sodium hydroxide, potassium hydroxide or ammonia water, the concentration of the alkali solution is 0.01-10M, and the pH is adjusted to 7.0-14.0.

[0023] Preferably, in step S5), the reagent for carbonizing the precipitated lithium is a carbonate, and the carbonate includes sodium carbonate, potassium carbonate or ammonium carbonate, and the molar amount of the carbonate added is 0.5 to 3 times the molar concentration of lithium ions in the filtrate.

[0024] The present application provides a method for recycling valuable metals from waste ternary lithium-ion batteries by graded method, which first pre-treats waste ternary lithium-ion batteries to obtain waste ternary battery core powder, then mixes the waste ternary battery core powder and a biomass carbon source for carbon thermal reduction roasting to obtain roasted solid powder, then acid-leaches the obtained roasted solid powder, obtains a leachate rich in manganese and lithium and an insoluble slag containing nickel and cobalt after solid-liquid separation, and finally reacts the leachate with bicarbonate to separate manganese, and carbonizes the obtained filtrate to precipitate lithium to separate lithium; in the process of recycling valuable metals from waste ternary lithium-ion batteries by graded method, the present application introduces a biomass carbon source and utilizes carbon thermal reduction roasting to convert high-valent metal ions in the waste ternary lithium-ion batteries into low-valent metal ions, and then realizes preliminary separation of valuable metals lithium manganese and nickel and cobalt by acid leaching, and finally realizes recycling of lithium manganese by subsequent recycling treatment; at the same time, the separated nickel-cobalt alloy can be widely used in industry due to its excellent performance. Therefore, the present application provides a method for graded recovery of valuable metals from waste ternary lithium-ion batteries, which can achieve preferential leaching of lithium and manganese while realizing the utilization of nickel and cobalt, ultimately improving the comprehensive utilization of resources of waste ternary lithium-ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic flow chart of a method for graded recovery of valuable metals from waste ternary lithium-ion batteries provided by the present invention. DETAILED DESCRIPTION

[0026] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0027] In view of the need for recycling valuable metal elements in waste ternary lithium-ion batteries in the prior art, the present application provides a method for recycling valuable metals from waste ternary lithium-ion batteries by graded recycling, the flow diagram of which is shown in FIG. Figure 1 As shown, specifically, the waste ternary lithium-ion batteries and biomass are first roasted, and then the obtained roasted powder is acid-leached to separate lithium manganese and nickel cobalt, and then the obtained nickel cobalt solution is reacted with bicarbonate to separate manganese ions, and finally the obtained filtrate is carbonized to precipitate lithium to separate lithium. Specifically, the embodiment of the present invention discloses a method for graded recovery of valuable metals from waste ternary lithium-ion batteries, comprising the following steps:

[0028] S1) pre-treating the waste ternary lithium-ion batteries to obtain waste ternary battery powder;

[0029] S2) mixing the waste ternary battery core powder and a biomass carbon source and performing carbon thermal reduction roasting to obtain a roasted solid powder;

[0030] S3) mixing the roasted solid powder with an acid solution, acid leaching, and then sequentially performing solid-liquid separation to obtain a leachate and an insoluble slag;

[0031] S4) mixing the leaching solution and alkali solution to adjust the pH, reacting with bicarbonate, and filtering to obtain a manganese carbonate solid phase and a filtrate;

[0032] S5) The filtrate is mixed with an alkaline solution to adjust the pH, and then carbonization is performed to precipitate lithium to obtain lithium carbonate.

[0033] In the process of recycling valuable metals from waste ternary lithium-ion batteries, the waste ternary lithium-ion batteries are first pretreated to obtain waste ternary battery core powder; the waste ternary lithium-ion batteries are waste ternary lithium-ion batteries well known to those skilled in the art, and their sources are not particularly limited in this application. Specifically, the components of the waste ternary lithium-ion batteries in the embodiments of the present application are shown in Table 1:

[0034] Table 1 Composition data of waste ternary lithium-ion batteries

[0035] The above-mentioned pretreatment may be carried out by discharging and crushing the waste ternary lithium-ion batteries, and then screening, magnetic separation, air separation, and grinding; or, the waste ternary lithium-ion batteries may be discharged and crushed; or, the waste ternary lithium-ion batteries may be discharged and crushed before grinding. The above-mentioned discharge, crushing, magnetic separation, air separation, and grinding are conventional technical methods in the field, and the specific implementation methods thereof are not particularly limited in this application. The particle size of the waste ternary battery core powder after the pretreatment of the waste ternary lithium-ion batteries is 50 to 200 meshes, and specifically, the particle size of the waste ternary battery core powder is 100 to 150 meshes.

[0036] In the present application, the above-mentioned waste ternary battery core powder and biomass carbon source are mixed and preferably subjected to carbon thermal reduction roasting under a protective atmosphere to obtain a roasted solid powder; in this process, due to the introduction of the biomass carbon source, the reducing gas generated by the pyrolysis of the biomass and the synergistic reduction effect of the biochar during the roasting process, the layered structure of the waste ternary battery core powder is destroyed, the octahedral lattice structure completely collapses, and the Ni atoms and Co atoms escape from the oxygen octahedron to form Ni metal and Co metal. At the same time, the Li element combines with CO2 to form Li2CO3, which is beneficial to the subsequent leaching process. Recovery; since the covalent bond of MnO is very strong, it will not undergo a reduction reaction with the reducing gas or biochar within the roasting temperature range, and therefore exists stably; in the present application, the reaction between the biomass carbon source and the waste ternary battery core powder is shown in the following formula:

[0037] ;

[0038] .

[0039] In the above process, the biomass carbon source includes one or more of chitosan, chitin and starch (processed from crops such as potatoes and cassava) extracted from shrimp and crab shells. The present application uses biomass as a carbon source, which has weak thermal stability and can be completely decomposed at 250°C to generate a large amount of small molecule reducing gas, thereby reacting with the waste ternary battery powder as above. The mass ratio of the biomass carbon source to the waste ternary battery powder is 1: (0.01~3), specifically, the mass ratio of the biomass carbon source to the waste ternary battery powder is 1: (0.1~2.5), more specifically, the mass ratio of the biomass carbon source to the waste ternary battery powder is 1: (0.2~1.0), more specifically, the mass ratio of the biomass carbon source to the waste ternary battery powder is 1: 0.3, 1: 0.5, 1: 0.6, 1: 0.7 or 1: 0.9. The calcination temperature is 300-1000°C, the time is 10min-5h, and the heating rate is 5-15°C / min; specifically, the calcination time is 350-750°C, the heating rate is 10-15°C / min, and the time is 1-4h; more specifically, the calcination time is 450-550°C, and the time is 2-3h. In this process, the mass ratio of biomass carbon source and waste ternary battery powder, calcination temperature and time will affect the leaching rate of Mn. Only in the appropriate range can the manganese in the waste ternary battery powder be completely reduced to MnO, and it can be fully leached in acid leaching to improve the leaching rate.

[0040] The present application then mixes the roasted solid powder with an acid solution, performs acid leaching, and then performs solid-liquid separation, so that Li2CO3, MnO in the roasted solid powder react with the acid solution to generate soluble lithium salts and soluble manganese salts, while nickel and cobalt do not participate in the reaction, and obtain a leaching solution rich in lithium and manganese, and nickel and cobalt remain in the insoluble slag, thereby achieving efficient separation of nickel and cobalt from lithium and manganese. The acid solution includes one of acetic acid, sulfuric acid, formic acid and hydrochloric acid, and the concentration of the acid solution is 0.1~3M, specifically, the concentration of the acid solution is 0.2~2M, and more specifically, the concentration of the acid solution is 0.5~1M; the time of the acid leaching is 2min~6h, and the temperature is 25~90℃; specifically, the time of the acid leaching is 30min~3h, and the temperature is 40~80℃; more specifically, the time of the acid leaching is 1~2h, and the temperature is 50~60℃. During the acid leaching process, the waste ternary battery powder mainly contains metal elements such as Ni, Co, Mn, Li, Cu, and Al. In order to obtain higher purity lithium carbonate and manganese carbonate in the later stage, the leaching rate of Mn and Li is maximized in the early acid leaching process to improve the recovery rate of the whole process, while the leaching rate of metal elements such as Ni, Co, Cu, and Al is reduced to the minimum to improve the purity of subsequent lithium carbonate and manganese carbonate products. The type of acid solution, the time and temperature of acid leaching will affect the leaching rate of Ni, Co, Mn, Li, Cu, and Al; if the acidity or concentration of the acid solution is low, MnO cannot be completely dissolved, which will also affect the leaching rate of Mn.

[0041] According to the present invention, the leaching solution obtained above is then treated to achieve separation of lithium and manganese; the present application determines the precipitation order of each metal based on the solubility product constant (Ksp) (as shown in Table 2) and the properties of the metal compound, and establishes a process route for first recovering manganese and then recovering lithium;

[0042] Table 2 Solubility product constants of lithium manganese compounds

[0043] The present application then mixes the leachate and the alkali solution to adjust the pH, and then reacts with bicarbonate, and obtains a manganese carbonate solid phase and a filtrate after filtration; the alkali solution includes one or both of ammonia water and sodium hydroxide, and the concentration of the alkali solution is 0.01~10M, specifically, the concentration of the alkali solution is 0.05~5M; more specifically, the concentration of the alkali solution is 0.5~3M; the alkali solution is used to adjust the pH of the filtrate to 3.0~10.0, specifically, the pH is 4~6. The bicarbonate includes one or more of NaHCO3, KHCO3 and NH3HCO3; the molar amount of the bicarbonate added is 0.5~3 times the molar concentration of lithium ions in the leachate, specifically, the molar amount of the bicarbonate added is 1.2~3 times the concentration of lithium ions in the leachate, and more specifically, the molar amount of the bicarbonate added is 1.5~2 times the concentration of lithium ions in the leachate. The added molar amount and pH value of the bicarbonate will affect the purity of the recovered metal.

[0044] According to the present invention, the filtrate and the alkali solution are finally mixed to adjust the pH, and then carbonization and lithium precipitation are carried out to obtain lithium carbonate; in this process, the alkali solution includes sodium hydroxide, potassium hydroxide or ammonia water, and the concentration of the alkali solution is 0.01~10M. Specifically, the alkali solution is selected from sodium hydroxide, and the concentration of the alkali solution is 0.05~5M, more specifically, the concentration of the alkali solution is 0.5~3M; the alkali solution is used to adjust the pH of the filtrate to 7.0~14.0, specifically, the pH is 10.0~12.0. The reagent for carbonization and precipitation of lithium is carbonate, and the molar amount of the carbonate added is 0.5~3 times the molar concentration of lithium ions in the filtrate, specifically, the molar amount of the carbonate added is 1.3~2.5 times the molar concentration of lithium ions in the filtrate, more specifically, the molar amount of the carbonate added is 1.5~2.0 times the molar concentration of lithium ions in the filtrate.

[0045] The present invention utilizes biomass such as chitosan, chitin, starch as a carbon source for reduction roasting, utilizes the reducing gas generated by pyrolysis to couple with the biomass carbonization process, converts the high-price metals in the waste ternary lithium ion battery materials into Li2CO3, Ni, Co, and MnO, and utilizes the characteristics of Li2CO3 and MnO that are more easily reacted with acid to separate Li, Mn from Ni and Co, and recovers Li and Mn in the form of lithium carbonate and manganese carbonate. Therefore, in addition to utilizing chitosan, chitin, and starch biomass with a wide range of sources and low prices as carbon sources for reduction roasting, the present invention also utilizes the reducing atmosphere generated by biomass pyrolysis to strengthen reduction roasting compared with the existing common carbon source carbon thermal reduction roasting, so that the roasting temperature is lower and the reducing agent cost is low, and finally realizes the stepwise separation and recovery of the valuable metal elements in the waste ternary lithium ion battery, which is conducive to the efficient recovery and comprehensive utilization of the valuable elements in the waste ternary lithium ion battery.

[0046] In order to further understand the present invention, the method for graded recovery of valuable metals from waste ternary lithium-ion batteries provided by the present invention is described in detail below in conjunction with the embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0047] Example 1

[0048] A method for recycling valuable metals from waste ternary lithium-ion batteries by classification, comprising the following steps:

[0049] Step (1) pretreatment: discharging the waste ternary lithium-ion battery to crush the battery core, and then screening, magnetic separation and sorting, and then grinding to a certain particle size, the particle size is 150 mesh, to obtain the waste ternary lithium-ion battery powder;

[0050] Step (2) mixing: the waste ternary lithium-ion battery powder obtained in step (1) is fully mixed with biomass chitin and chitosan in a mass ratio of 0.01:1;

[0051] Step (3) Calcination: Place the mixed battery material obtained in step (2) into a nitrogen-filled tubular furnace for calcination at a heating rate of 10°C / min, raise the temperature to 350°C, and calcine for 1 hour;

[0052] Step (4) leaching: the calcined powder obtained in step (3) is placed in a 0.5 M formic acid solution at a leaching temperature of 60° C. and stirred for 6 hours. Li and Mn are dissolved to obtain a leachate, wherein the nickel-cobalt alloy remains in the insoluble slag phase. The leaching rate is shown in Table 3, wherein the contents of nickel and cobalt in the nickel-cobalt alloy are detected according to a method well known to those skilled in the art, and finally the leaching rates of nickel and cobalt are obtained respectively;

[0053] Step (5) separation: performing solid-liquid separation on the leaching solution to obtain a filtrate and an insoluble slag, thereby achieving efficient separation of nickel and cobalt from lithium and manganese;

[0054] Step (6) Mn recovery: add 0.5M ammonia solution to the filtrate obtained in step (5), adjust the pH to 4.0, add 1.2 times the theoretical molar value of KHCO3, stir at 45°C for 3h, filter, and obtain a filtrate and a manganese carbonate solid phase, the purity of the manganese carbonate solid phase is 83.12%;

[0055] Step (7) Recovery of Li: NaOH was added to the filtrate obtained in step (6) to adjust the pH to 12, and 1.5 times the theoretical molar value of Na2CO3 was added at 65°C. The mixture was stirred for 4 hours and filtered to obtain lithium carbonate with a purity of 93.42%.

[0056] Table 3 Lithium nickel cobalt manganese leaching rate data table of this example (%)

[0057] Example 2

[0058] A method for recycling valuable metals from waste ternary lithium-ion batteries by classification, comprising the following steps:

[0059] Step (1) pretreatment: soak the waste ternary lithium-ion batteries in a NaCl solution overnight to allow them to be fully discharged, and then crush them to a particle size of 50 mesh;

[0060] Step (2) mixing: the waste ternary lithium-ion battery powder obtained in step (1) is fully mixed with biomass starch and chitosan in a mass ratio of 0.2:1;

[0061] Step (3) Calcination: The mixed battery material obtained in step (2) is placed in a tubular furnace under nitrogen conditions for calcination at a heating rate of 10°C / min, the temperature is raised to 450°C, and calcined for 3 hours;

[0062] Step (4) leaching: the calcined powder obtained in step (3) is put into a 2 mol / L acetic acid solution at a leaching temperature of 60° C. and stirred for 30 min to obtain a leachate, in which Li and Mn are dissolved and the nickel-cobalt alloy remains in the slag phase. The leaching rate is shown in Table 4, wherein the contents of nickel and cobalt in the nickel-cobalt alloy are detected according to a method well known to those skilled in the art, and finally the leaching rates of nickel and cobalt are obtained respectively;

[0063] Step (5) separation: performing solid-liquid separation on the leaching solution of step (4) to obtain a filtrate and an insoluble slag, thereby achieving efficient separation of nickel and cobalt from lithium and manganese;

[0064] Step (6) Mn recovery: add 0.05M ammonia solution to the filtrate obtained in step (5), adjust the pH to 6.0, add 2 times the theoretical molar value of NaHCO3, stir at 45°C for 2h, filter, and obtain manganese carbonate and filtrate. The purity of manganese carbonate is 80.62%;

[0065] Step (7) Recovery of Li: NaOH was added to the filtrate obtained in step (6) to adjust the pH to 14. At 65° C., 1.3 times the theoretical molar value of Na2CO3 was added. The mixture was stirred for 6 h and filtered to obtain lithium carbonate with a purity of 89.16%.

[0066] Table 4 Lithium nickel cobalt manganese leaching rate data table of this example (%)

[0067] Example 3

[0068] A method for recycling valuable metals from waste ternary lithium-ion batteries by classification, comprising the following steps:

[0069] Step (1) pretreatment: soak the waste ternary lithium-ion battery in a NaCl solution overnight for 10 hours to allow it to be fully discharged, and then crush it to a particle size of 100 mesh;

[0070] Step (2) mixing: the waste ternary lithium-ion battery powder obtained in step (1) is fully mixed with chitosan at a mass ratio of 0.5:1;

[0071] Step (3) Calcination: The mixed battery material obtained in step (2) is placed in a tubular furnace under nitrogen conditions for calcination at a heating rate of 10°C / min, the temperature is raised to 550°C, and calcined for 4 hours;

[0072] Step (4) leaching: the calcined powder obtained in step (3) was put into a 3M HCl solution at a leaching temperature of 60°C and stirred for 30 minutes to obtain a leachate, in which Li and Mn were dissolved, while the nickel-cobalt alloy remained in the slag phase. The leaching rate is shown in Table 5, wherein the contents of nickel and cobalt in the nickel-cobalt alloy were detected according to a method well known to those skilled in the art, and finally the leaching rates of nickel and cobalt were obtained respectively;

[0073] Step (5) separation: performing solid-liquid separation on the leaching solution of step (4) to obtain a filtrate and an insoluble slag, thereby achieving efficient separation of nickel and cobalt from lithium and manganese;

[0074] Step (6) Mn recovery: add 0.05M NaOH solution to the filtrate obtained in step (5), adjust the pH to 6.0, add 1.5 times the theoretical molar value of KHCO3, stir at 65°C for 3h, filter, and obtain a filtrate and a manganese carbonate solid phase, the purity of the manganese carbonate solid phase is 79.63%;

[0075] Step (7) Li recovery: NaOH was added to the filtrate obtained in step (6) to adjust the pH to 14, and 1.3 times the theoretical molar value of Na2CO3 was added at 65°C. The mixture was stirred for 6 hours and filtered to obtain a lithium carbonate solid phase with a purity of 88.65%.

[0076] Table 5 Lithium nickel cobalt manganese leaching rate data table of this example (%)

[0077] Example 4

[0078] A method for recycling valuable metals from waste ternary lithium-ion batteries by classification, comprising the following steps:

[0079] Step (1) pretreatment: soak the waste ternary lithium-ion batteries in a NaCl solution overnight for 20 hours to allow them to be fully discharged, and then crush them to a particle size of 200 mesh;

[0080] Step (2) mixing: the waste ternary lithium-ion battery powder obtained in step (1) is fully mixed with starch in a mass ratio of 0.9:1;

[0081] Step (3) Calcination: The mixed battery material obtained in step (2) is placed in a tubular furnace under nitrogen conditions for calcination at a heating rate of 10°C / min, the temperature is raised to 750°C, and calcined for 5 hours;

[0082] Step (4) leaching: the calcined powder obtained in step (3) is put into a 3M sulfuric acid solution at a leaching temperature of 60° C. and stirred for 30 minutes to obtain a leaching solution, in which 98% of Li and Mn are dissolved, while the nickel-cobalt alloy remains in the slag phase;

[0083] Step (5) separation: the leaching solution of step (4) is subjected to solid-liquid separation to obtain a filtrate and an insoluble residue, thereby achieving efficient separation of nickel-cobalt and lithium-manganese. The leaching rates are shown in Table 6, wherein the contents of nickel and cobalt in the nickel-cobalt alloy are detected according to methods well known to those skilled in the art, and finally the leaching rates of nickel and cobalt are obtained respectively;

[0084] Step (6) Mn recovery: add 3M NaOH solution to the filtrate obtained in step (5), adjust the pH to 6.0, add 3 times the theoretical molar value of NaHCO3, stir at 45°C for 3h, filter, and obtain a manganese carbonate solid phase and a filtrate. The purity of the manganese carbonate solid phase is 75.12%;

[0085] Step (7) Li recovery: NaOH was added to the filtrate obtained in step (6) to adjust the pH to 14, and 1.3 times the theoretical molar value of Na2CO3 was added at 65°C. The mixture was stirred for 6 hours and filtered to obtain a lithium carbonate solid phase with a purity of 94.16%.

[0086] Table 6 Lithium nickel cobalt manganese leaching rate data table of this example (%)

[0087] Example 5

[0088] A method for recycling valuable metals from waste ternary lithium-ion batteries by classification, comprising the following steps:

[0089] Step (1) pretreatment: soak the waste ternary lithium-ion batteries in a NaCl solution overnight to allow them to be fully discharged, and then crush them to a particle size of 50 mesh;

[0090] Step (2) mixing: the waste ternary lithium ion battery powder obtained in step (1) is thoroughly mixed with chitosan at a mass ratio of 0.2:1;

[0091] Step (3) Calcination: The mixed battery material obtained in step (2) is placed in a tubular furnace under nitrogen conditions for calcination at a heating rate of 10°C / min, the temperature is raised to 450°C, and calcined for 3 hours;

[0092] Step (4) leaching: the calcined powder obtained in step (3) was put into a 2M acetic acid solution at a leaching temperature of 60° C. and stirred for 30 min to obtain a leachate, wherein Li and Mn were dissolved, while the nickel-cobalt alloy remained in the slag phase. The leaching rate is shown in Table 7, wherein the contents of nickel and cobalt in the nickel-cobalt alloy were detected according to a method well known to those skilled in the art, and finally the leaching rates of nickel and cobalt were obtained respectively;

[0093] Step (5) separation: performing solid-liquid separation on the leaching solution of step (4) to obtain a filtrate and an insoluble slag, thereby achieving efficient separation of nickel and cobalt from lithium and manganese;

[0094] Step (6) Mn recovery: add 0.05M ammonia solution to the filtrate obtained in step (5), adjust the pH to 6.0, add 2 times the theoretical molar value of NaHCO3, stir at 45°C for 2h, filter, and obtain a filtrate and manganese carbonate with a purity of 80.62%;

[0095] Step (7) Recovery of Li: NaOH was added to the filtrate obtained in step (6) to adjust the pH to 14. At 65° C., 1.3 times the theoretical molar value of Na2CO3 was added. The mixture was stirred for 6 h and filtered to obtain lithium carbonate with a purity of 89.16%.

[0096] Comparative Example 1

[0097] A method for recycling valuable metals from waste ternary lithium-ion batteries by classification, comprising the following steps:

[0098] Step (1) pretreatment: soak the waste ternary lithium-ion batteries in a NaCl solution overnight to allow them to be fully discharged, and then crush them to a particle size of 50 mesh;

[0099] Step (2) mixing: the waste ternary lithium-ion battery powder obtained in step (1) is fully mixed with ordinary carbon powder at a mass ratio of 0.2:1;

[0100] Step (3) Calcination: The mixed battery material obtained in step (2) is placed in a tubular furnace under nitrogen conditions for calcination at a heating rate of 10°C / min, the temperature is raised to 450°C, and calcined for 3 hours;

[0101] Step (4) leaching: the calcined powder obtained in step (3) was put into a 2M acetic acid solution at a leaching temperature of 60° C. and stirred for 30 min to obtain a leachate, wherein Li and Mn were dissolved, while the nickel-cobalt alloy remained in the slag phase. The leaching rate is shown in Table 7, wherein the contents of nickel and cobalt in the nickel-cobalt alloy were detected according to a method well known to those skilled in the art, and finally the leaching rates of nickel and cobalt were obtained respectively;

[0102] Step (5) separation: performing solid-liquid separation on the leaching solution of step (4) to obtain a filtrate and an insoluble slag, thereby achieving efficient separation of nickel and cobalt from lithium and manganese;

[0103] Step (6) Mn recovery: add 0.05M ammonia solution to the filtrate obtained in step (5), adjust the pH to 6.0, add 2 times the theoretical molar value of NaHCO3, stir at 45°C for 2h, filter, and obtain a filtrate and manganese carbonate with a purity of 76.23%;

[0104] Step (7) Li recovery: NaOH was added to the filtrate obtained in step (6) to adjust the pH to 14, and 1.3 times the theoretical molar value of Na2CO3 was added at 65°C. The mixture was stirred for 6 hours and filtered to obtain lithium carbonate with a purity of 83.62%.

[0105] Table 7 Leaching rate data table of lithium nickel cobalt manganese aluminum copper in Example 5 and Comparative Example 1 (%)

[0106] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0107] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for recycling valuable metals from waste ternary lithium-ion batteries. The following steps are involved: S1) pre-treating the waste ternary lithium-ion batteries to obtain waste ternary battery powder; S2) mixing the waste ternary battery core powder and a biomass carbon source and performing carbon thermal reduction roasting to obtain a roasted solid powder; S3) mixing the roasted solid powder with an acid solution, acid leaching, and then performing solid-liquid separation to obtain a leachate and an insoluble slag; S4) mixing the leaching solution and alkali solution to adjust the pH, reacting with bicarbonate, and filtering to obtain a manganese carbonate solid phase and a filtrate; S5) The filtrate is mixed with an alkaline solution to adjust the pH, and then carbonization is performed to precipitate lithium to obtain lithium carbonate.

2. The method according to claim 1, It is characterized in that In step S1), the pre-processing is specifically as follows: The waste ternary lithium-ion batteries are first subjected to discharge and crushing treatment, and then sieved, magnetically separated and air-separated in sequence to obtain waste ternary battery core powder; The particle size of the waste ternary battery core powder is 50-200 mesh.

3. The method according to claim 1, It is characterized in that In step S2), the biomass carbon source includes one or more of chitosan, chitin and starch, and the mass ratio of the biomass carbon source to the waste ternary battery core powder is 1: (0.01~3).

4. The method according to claim 1, It is characterized in that In step S2), the temperature of the carbon thermal reduction calcination is 300-1000° C., and the time is 10 min-5 h.

5. The method according to claim 1, It is characterized in that In step S3), the acid solution includes one of acetic acid, sulfuric acid, formic acid and hydrochloric acid, and the concentration of the acid solution is 0.1-3M.

6. The method according to claim 1, It is characterized in that In step S3), the acid leaching temperature is 25-90° C. and the time is 2 min-6 h.

7. The method according to claim 1, It is characterized in that In step S4), the alkali solution includes one or both of ammonia water and sodium hydroxide, the concentration of the alkali solution is 0.01-10M, and the pH is adjusted to 3.0-10.

0.

8. The method according to claim 1, It is characterized in that In step S4), the bicarbonate includes NaHCO 3 , KHCO 3 and NH 3 HCO 3 One or more of; the molar amount of the bicarbonate added is 0.5 to 3 times the molar concentration of lithium ions in the leachate.

9. The method according to claim 1, It is characterized in that In step S5), the alkali solution includes sodium hydroxide, potassium hydroxide or ammonia water, the concentration of the alkali solution is 0.01-10M, and the pH is adjusted to 7.0-14.

0.

10. The method according to claim 1, It is characterized in that In step S5), the reagent for carbonizing the precipitated lithium is a carbonate, and the carbonate includes sodium carbonate, potassium carbonate or ammonium carbonate. The molar amount of the added carbonate is 0.5 to 3 times the molar concentration of lithium ions in the filtrate.

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