Lithium battery valuable metal separation and recovery method based on multi-stage synergistic extraction

Abstract

The invention provides a lithium battery valuable metal separation and recovery method based on multi-stage synergistic extraction. The method comprises the following steps: obtaining an electrode material from a waste lithium battery, and crushing and roasting the electrode material; carrying out multi-stage extraction on the roasted electrode material, and sequentially carrying out lithium element extraction, cobalt and nickel element extraction and manganese element extraction; and carrying out back extraction, separation and metal recovery on the lithium-containing organic phase, the cobalt-nickel-containing organic phase and the manganese-containing organic phase obtained by the multi-stage extraction to respectively obtain lithium carbonate, metal cobalt, metal nickel and manganese dioxide. According to the method, a multi-stage synergistic extraction process is adopted, a specific extraction agent and optimized extraction conditions are selected according to the properties of different valuable metals in the lithium battery, and the valuable metals are extracted in a graded and coordinated manner in combination with a pi-pi conjugated amphiphilic dissolution aid, so that the valuable metals such as lithium, cobalt, nickel, manganese and the like are efficiently separated and recycled, and the resource utilization rate is effectively increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery material recovery, and in particular relates to a method for separating and recovering valuable metals from lithium batteries based on multi-stage synergistic extraction. Background Art

[0002] With the increasing use of lithium batteries, a large amount of waste lithium-ion batteries is generated. However, if these large quantities of used lithium-ion batteries are not properly handled, they will not only waste valuable metal resources such as lithium, cobalt, nickel, and manganese, but also cause serious environmental pollution. Recovering these valuable metals from waste lithium-ion batteries has high economic value.

[0003] Currently, the main recycling processes for used lithium batteries include pyrometallurgy, hydrometallurgy, and biometallurgy. Pyrometallurgy is energy-intensive, highly polluting, and has limited recovery rates for valuable metals. Biometallurgy has a long recycling cycle and stringent environmental requirements. The extraction and separation process in traditional hydrometallurgy often suffers from low extraction efficiency, incomplete metal separation, and high extraction agent loss, making it difficult to achieve efficient separation and recovery of valuable metals from lithium batteries. Therefore, there is an urgent need to develop an efficient and environmentally friendly process for recycling valuable metals from lithium batteries.

[0004] For example, the invention application with publication number CN119100345A discloses a mixed recycling process for waste lithium iron phosphate battery powder and waste ternary lithium battery powder. Using waste lithium iron phosphate battery powder and waste ternary lithium battery powder as raw materials, the process achieves efficient separation and recovery of valuable metal ions and graphite through a series of processes, including roasting and water leaching, first-stage organic acid leaching, second-stage organic acid leaching, acid dissolution, and resin copper removal. The process is simple and environmentally friendly. The roasting process removes fluorine from both waste battery powders, preventing fluorine-induced corrosion damage to the autoclave during the subsequent high-pressure impurity removal process and improving the equipment's safety factor.

[0005] For another example, the invention application with publication number CN119979908A discloses a method for recovering valuable metals from waste lithium-ion batteries, comprising the steps of sequentially soaking and calcining the positive electrode sheets of the waste lithium-ion batteries in an organic solvent to obtain a calcined product; mixing the calcined product with waste biomass materials, and performing reduction calcination under a protective atmosphere to obtain a reduced product; subjecting the reduced product to a carbonic acid water leaching reaction, and then filtering the obtained carbonic acid water leaching reaction liquid; concentrating and crystallizing the filtrate to obtain lithium carbonate, subjecting the filter residue to acid leaching, and then filtering the obtained acid leaching liquid to obtain a solution containing valuable metal salts.

[0006] However, the above patents often only target the recycling of one type of waste battery material, and a large amount of reducing agents, precipitants, chelating agents, etc. need to be added during the processing. On the one hand, this leads to increased costs and complicated processing techniques. On the other hand, the introduction of too many substances into the system easily leads to a decrease in the recovery effect of valuable metals. Summary of the Invention

[0007] In order to solve the above-mentioned technical problems existing in the prior art, the present invention provides a method for separating and recovering valuable metals in lithium batteries based on multi-stage collaborative extraction, which is used to achieve efficient separation and recovery of valuable metals such as lithium, cobalt, nickel, and manganese, and improve resource utilization.

[0008] The present invention provides a method for separating and recovering valuable metals from lithium batteries based on multi-stage synergistic extraction. The method comprises the following steps, calculated by mass: (1) Discharge and disassemble the waste lithium batteries to obtain the battery shell, electrode materials and electrolyte, and crush and roast the electrode materials; (2) Multi-stage extraction: 12-18 parts of calcined electrode material and 70-90 parts of lithium element extractant are used for extraction reaction to separate the lithium-containing organic phase and the raffinate phase to complete the first stage extraction; An extraction reaction is carried out using 12-18 parts of the raffinate phase after the first stage extraction, 56-72 parts of a cobalt-nickel element extractant, 0.1-0.5 parts of a π-π conjugated amphiphilic solubilizer, and 1-4 parts of kerosene to separate an organic phase containing cobalt and nickel and a secondary raffinate phase, thereby completing the second stage extraction; An extraction reaction is carried out using 12-18 parts of the raffinate phase after the second stage extraction, 36-54 parts of a manganese element extractant, and 1-5 parts of isooctyl alcohol to separate the manganese-containing organic phase and the final raffinate phase, thereby completing the third stage extraction; (3) The organic phase containing lithium, the organic phase containing cobalt and nickel, and the organic phase containing manganese are stripped and separated, and the separated valuable metal aqueous phase is subjected to metal recovery to obtain lithium carbonate, metallic cobalt, metallic nickel, and manganese dioxide, respectively.

[0009] The present invention adopts a multi-stage collaborative extraction process. According to the properties of different valuable metals in lithium batteries, specific extractants and optimized extraction conditions are selected to extract valuable metals in a graded manner, thereby achieving efficient separation and recovery of valuable metals such as lithium, cobalt, nickel, and manganese, and effectively improving resource utilization. The π-π conjugated structure in the π-π conjugated amphiphilic dissolution aid is tightly combined with carbon impurities through π-π stacking, so that the carbon impurities are dispersed in the solution. The citrate group at the hydrophilic end chelates with the metal ions to promote dissolution. In the acidic dissolution system, the dissolution aid can reduce the surface tension of the solution, enhance the wettability of the acid solution on the material, and at the same time inhibit the hydrolysis of metal ions to form colloids, thereby maintaining the clarity of the solution and facilitating subsequent separation.

[0010] Preferably, step (1) specifically includes: placing the waste lithium battery in a special discharge device, using a salt water immersion discharge method to completely eliminate the residual electricity in the battery; using automated disassembly equipment to disassemble the shell of the discharged lithium battery to separate the battery shell, electrode material and electrolyte; The disassembled electrode materials are put into a crusher for crushing, and the crushed electrode materials are roasted.

[0011] By calcining, the organic binder and carbon material in the electrode material can be effectively removed, the metal oxide is exposed, and the leaching rate of metal ions is increased.

[0012] More preferably, the particle size of the electrode material after the crushing process is 1-3 mm.

[0013] Preferably, the calcination temperature in step (1) is 400-500° C., and the calcination time is 90-120 min.

[0014] Preferably, in step (2), the temperature of the first stage extraction is 30-40°C, the stirring speed is 200-300 r / min, and the extraction reaction time is 20-30 min.

[0015] The lithium element in the electrode material is transferred to the extractant through the first stage extraction to form a lithium-containing organic phase. After the extraction reaction is completed, the mixture is allowed to stand and stratify to separate the lithium-containing organic phase and the raffinate phase.

[0016] Preferably, in step (2), the temperature of the second stage extraction is 40-50°C, the stirring speed is 250-350 r / min, and the extraction reaction time is 30-40 min.

[0017] The cobalt and nickel elements are fully extracted into the organic phase through the second stage extraction. After the extraction reaction is completed, the organic phase containing cobalt and nickel and the secondary raffinate phase are separated by centrifugation.

[0018] Preferably, in step (2), the temperature of the third stage extraction is 50-60°C, the stirring speed is 300-400 r / min, and the extraction reaction time is 40-50 min.

[0019] The manganese element is extracted into the organic phase through the third stage extraction. After the extraction reaction is completed, the manganese-containing organic phase and the final raffinate phase are separated by centrifugation.

[0020] Preferably, in step (2), the method for preparing the π-π conjugated amphiphilic solubilizing agent comprises the following steps, calculated by weight: 20-40 parts of vinylferrocene and 27-55 parts of triallyl citrate are uniformly dispersed in a solvent; Add 0.3-2 parts of initiator and induce free radical polymerization reaction under inert atmosphere to generate amphiphilic coordination salt containing π-π conjugated structure; After the reaction is completed, the solvent is removed to obtain a π-π conjugated amphiphilic solubilizing agent.

[0021] Under the action of the initiator, the vinyl group (C=C double bond) in vinylferrocene can form free radicals or ionic intermediates. These intermediates can undergo addition reactions with the ester group or other active groups in triallyl citrate, gradually extending the chain segments and eventually forming amphiphilic coordination salts containing a π-π conjugated structure, which tightly bind to carbon impurities and chelate with metal ions to promote dissolution.

[0022] More preferably, the solvent is anhydrous ethanol, with a mass fraction of 200-500 parts; during dispersion, the mixture is stirred and mixed at a temperature of 70-80°C until uniformly dispersed; The initiator is azobisisobutyronitrile.

[0023] Preferably, in step (2), the volume ratio of carbonates in the lithium extractant is 15%-20%, wherein the carbonates include dimethyl carbonate and diethyl carbonate, and the volume ratio of dimethyl carbonate to diethyl carbonate is 1:1.

[0024] Preferably, in step (2), the volume proportion of di-2-ethylhexyl phosphoric acid in the cobalt-nickel element extractant is 10%-15%.

[0025] Preferably, in step (2), the volume proportion of trioctylamine in the manganese element extractant is 8%-12%.

[0026] Preferably, in step (3), the lithium-containing organic phase is stripped and separated, comprising: adding the lithium-containing organic phase and the lithium element stripping agent into a stripping reactor in a volume ratio of 1:1-2, performing the stripping reaction for 15-25 min at 25-30° C. and a stirring speed of 200-300 r / min, and separating the lithium-containing aqueous phase and the lithium element regeneration extractant.

[0027] Preferably, in step (3), the organic phase containing cobalt and nickel is stripped and separated, comprising: adding the organic phase containing cobalt and nickel and a cobalt-nickel element stripping agent into a stripping reactor in a volume ratio of 1:1-1.5, performing a stripping reaction for 20-30 min at 30-40° C. and a stirring speed of 200-300 r / min, and separating the aqueous phase containing cobalt and nickel and the cobalt-nickel element regeneration extractant.

[0028] Preferably, in step (3), the manganese-containing organic phase is stripped and separated, comprising: adding the manganese-containing organic phase and the manganese element stripping agent into a stripping reaction kettle in a volume ratio of 1:1-1.2, performing the stripping reaction for 15-25 min at 30-35° C. and a stirring speed of 200-300 r / min, and separating the manganese-containing aqueous phase and the manganese element regeneration extractant.

[0029] Further preferably, the lithium stripping agent is a hydrochloric acid solution with a mass concentration of 5%-10%.

[0030] Further preferably, the cobalt-nickel stripping agent is a sulfuric acid solution with a mass concentration of 10%-20%.

[0031] Further preferably, the manganese stripping agent is a sodium hydroxide solution with a mass concentration of 5%-10%.

[0032] Preferably, in step (3), the separated valuable metal aqueous phase is subjected to metal recovery, comprising: A lithium-containing aqueous phase, after removing the aqueous phase, obtains lithium carbonate; The aqueous phase containing cobalt and nickel is passed through a macroporous sulfonic acid styrene-based cation exchange resin combined with an electrodeposition method to obtain metallic cobalt and metallic nickel; The pH value of the manganese-containing aqueous phase is adjusted to 10-11 to precipitate manganese hydroxide, which is then calcined at high temperature to obtain manganese dioxide.

[0033] Further optionally, the lithium-containing aqueous phase is concentrated by evaporation, crystallized by cooling, filtered, washed and dried to obtain lithium carbonate.

[0034] Further preferably, evaporation concentration is achieved by evaporating and concentrating the lithium-containing aqueous phase at 90° C.-100° C. to 1 / 5 of the original solution volume.

[0035] Preferably, the current density of the electrodeposition is 16-20 A / m² and the temperature is 40-50°C.

[0036] Preferably, the calcination temperature is 400-600° C., and the calcination time is 180 min.

[0037] Compared with the prior art, the present invention has the following beneficial effects: (1) Enhance the synergy between impurity dispersion and metal dissolution: By preparing π-π conjugated amphiphilic dissolution aids for multi-stage extraction of electrode materials, the dispersion efficiency of carbon impurities is improved, the leaching rate of various valuable metal ions is effectively increased, and the stability of the dissolution system is significantly improved.

[0038] (2) Reduce solution viscosity and filtration resistance: In an acidic dissolution system, the prepared π-π conjugated amphiphilic solubilizer can effectively inhibit the formation of colloidal substances during the dissolution process, reduce solution viscosity, maintain solution clarity, and shorten filtration time.

[0039] (3) Efficient separation and recovery: The present invention adopts a multi-stage collaborative extraction process. According to the properties of different valuable metals in lithium batteries, specific extractants and optimized extraction conditions are selected to achieve efficient separation and recovery of valuable metals such as lithium, cobalt, nickel, and manganese, effectively improving resource utilization. DETAILED DESCRIPTION

[0040] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following is a detailed description in combination with embodiments and comparative examples.

[0041] Example 1 The preparation method of the π-π conjugated amphiphilic solubilizing agent specifically comprises the following steps: H1: Heat 20 g of vinylferrocene, 200 g of anhydrous ethanol, and 27 g of triallyl citrate to 70°C and stir to mix; H2: Add 0.3 g of azobisisobutyronitrile as initiator and react at 80°C for 4 h under a nitrogen atmosphere to generate an amphiphilic coordination salt containing a π-π conjugated structure through free radical polymerization; H3: After the reaction is completed, the ethanol is removed by distillation under reduced pressure, and the mixture is ground into powder to obtain a π-π conjugated amphiphilic solubilizing agent.

[0042] A method for separating and recovering valuable metals from lithium batteries based on multi-stage synergistic extraction, the operating steps of which are as follows: (1) Discharging and dismantling of waste lithium batteries: Place the used lithium batteries in a special discharge device and use the salt water immersion discharge method to completely eliminate the residual power inside the battery; use automated disassembly equipment to disassemble the discharged lithium battery shell and separate the battery shell, electrode material and electrolyte; Electrode material crushing and roasting: The disassembled electrode materials were placed in a crusher and crushed to a particle size of 3 mm. The crushed electrode materials were calcined at 400°C for 90 minutes to remove organic binders and carbon impurities in the electrode materials, expose metal oxides, and increase the leaching rate of metal ions. (2) Multi-stage synergistic extraction: First stage extraction, lithium extraction: 12 g of the calcined electrode material and 70 g of a lithium extraction agent were added to an extraction reactor, and the extraction reaction was carried out at 30°C and a stirring speed of 200 r / min for 20 minutes. The lithium element in the electrode material was transferred to the extraction agent to form a lithium-containing organic phase. After the extraction reaction was completed, the mixture was allowed to stand for stratification to separate the lithium-containing organic phase and the raffinate phase. Second stage extraction, extraction of cobalt and nickel elements: 12 g of the raffinate phase after the first stage extraction was added to a new extraction reactor, and 56 g of a cobalt-nickel extractant, 0.1 g of a π-π conjugated amphiphilic solubilizer, and 1 g of kerosene were added. The extraction reaction was carried out at 40°C and a stirring speed of 250 r / min for 30 min to fully extract the cobalt and nickel elements into the organic phase. After the extraction reaction, the organic phase containing cobalt and nickel and the secondary raffinate phase were separated by centrifugation. The third stage of extraction, manganese extraction: 12 g of the secondary raffinate phase after the second stage extraction was added to an extraction reactor, 36 g of a manganese element extractant and 1 g of isooctyl alcohol were added, and the extraction reaction was carried out at 50°C and a stirring speed of 300 r / min for 40 min to extract the manganese element into the organic phase. After the extraction reaction was completed, the manganese-containing organic phase and the final raffinate phase were separated by static stratification. (3) Back extraction: Lithium stripping: The lithium-containing organic phase and the stripping agent are added to the stripping reactor in a volume ratio of 1:1. The stripping reaction is carried out at 25°C and a stirring speed of 200 r / min for 15 minutes to transfer the lithium element from the organic phase to the aqueous phase. The lithium-containing aqueous phase and the regenerated extractant are separated by static stratification, and the regenerated extractant can be recycled. Stripping of cobalt and nickel elements: The organic phase containing cobalt and nickel and the stripping agent are added to a stripping reactor in a volume ratio of 1:1. The stripping reaction is carried out at 30°C and a stirring speed of 200 r / min for 20 minutes to transfer the cobalt and nickel elements from the organic phase to the aqueous phase. The aqueous phase containing cobalt and nickel and the regenerated extractant are separated by centrifugation, and the regenerated extractant can be recycled. Manganese stripping: The manganese-containing organic phase and the stripping agent are added to the stripping reaction kettle in a volume ratio of 1:1. The stripping reaction is carried out at 30°C and a stirring speed of 200 r / min for 15 minutes to transfer the manganese element from the organic phase to the aqueous phase. The manganese-containing aqueous phase and the regenerated extractant are separated by static stratification, and the regenerated extractant can be recycled. (4) Metal recycling: Lithium recovery: The lithium-containing aqueous phase is evaporated and concentrated at 90°C to 1 / 5 of the original solution volume, cooled for crystallization, filtered, washed, and dried to obtain lithium carbonate; Cobalt and nickel element recovery: The aqueous phase containing cobalt and nickel is purified by passing it through a macroporous sulfonic acid styrene-based cation exchange resin to remove impurity ions. Then, metallic cobalt and metallic nickel are obtained at the cathode by electrodeposition at a current density of 16 A / m² and a temperature of 40°C. Manganese recovery: The pH value of the manganese-containing aqueous phase was adjusted to 10 to precipitate manganese ions in the form of manganese hydroxide precipitate. After filtering and washing, the manganese hydroxide precipitate was calcined at 400° C. for 180 min to obtain manganese dioxide.

[0043] The lithium element extractant is a carbonate extractant with a volume fraction of 15%; the carbonate extractant is a mixed solution of dimethyl carbonate and diethyl carbonate with a volume ratio of 1:1.

[0044] The cobalt and nickel element extractant is di-2-ethylhexyl phosphoric acid with a volume fraction of 10%.

[0045] The manganese element extractant is trioctylamine with a volume fraction of 8%.

[0046] The lithium element stripping agent is a hydrochloric acid solution with a mass concentration of 5%.

[0047] The cobalt-nickel element stripping agent is a sulfuric acid solution with a mass concentration of 10%.

[0048] The manganese element stripping agent is a sodium hydroxide solution with a mass concentration of 5%.

[0049] Example 2 The preparation method of the π-π conjugated amphiphilic solubilizing agent specifically comprises the following steps: H1: Heat 25 g vinylferrocene, 300 g anhydrous ethanol, and 36 g triallyl citrate to 75°C and stir to mix; H2: Add 1 g of initiator azobisisobutyronitrile and react at 85°C for 5 h under a nitrogen atmosphere to generate an amphiphilic coordination salt containing a π-π conjugated structure through free radical polymerization; H3: After the reaction is completed, the ethanol is removed by distillation under reduced pressure, and the mixture is ground into powder to obtain a π-π conjugated amphiphilic solubilizing agent.

[0050] A method for separating and recovering valuable metals from lithium batteries based on multi-stage synergistic extraction, the operating steps of which are as follows: (1) Discharging and dismantling of waste lithium batteries: Place the used lithium batteries in a special discharge device and use the salt water immersion discharge method to completely eliminate the residual power inside the battery; use automated disassembly equipment to disassemble the discharged lithium battery shell and separate the battery shell, electrode material and electrolyte; Electrode material crushing and roasting: The disassembled electrode materials were placed in a crusher and crushed to a particle size of 2 mm. The crushed electrode materials were calcined at 440°C for 100 minutes to remove the organic binder and carbon material in the electrode materials, expose the metal oxides, and increase the leaching rate of metal ions. (2) Multi-stage synergistic extraction: First stage extraction, lithium extraction: 14 g of the electrode material calcined at high temperature and 75 g of a lithium extraction agent were added to an extraction reactor, and the extraction reaction was carried out at 35°C and a stirring speed of 240 r / min for 25 minutes to transfer the lithium element in the electrode material to the extraction agent to form a lithium-containing organic phase. After the extraction reaction was completed, the mixture was allowed to stand and separate the lithium-containing organic phase and the raffinate phase. Second stage extraction, extraction of cobalt and nickel elements: 14 g of the raffinate phase after the first stage extraction was added to a new extraction reactor, and 60 g of a cobalt-nickel extractant, 0.2 g of a π-π conjugated amphiphilic solubilizer, and 2 g of kerosene were added. The extraction reaction was carried out at 45°C and a stirring speed of 300 r / min for 35 min to fully extract the cobalt and nickel elements into the organic phase. After the extraction reaction, the organic phase containing cobalt and nickel and the secondary raffinate phase were separated by centrifugation. The third stage of extraction, manganese extraction: 14 g of the secondary raffinate phase after the second stage extraction was added to an extraction reactor, and 42 g of a manganese element extractant and 2 g of isooctyl alcohol were added. The extraction reaction was carried out at 55°C and a stirring speed of 350 r / min for 45 min to extract the manganese element into the organic phase. After the extraction reaction was completed, the manganese-containing organic phase and the final raffinate phase were separated by standing and stratification. (3) Back extraction: Lithium stripping: The lithium-containing organic phase and the stripping agent are added to the stripping reaction kettle in a volume ratio of 1:1.5, and the stripping reaction is carried out at 25°C and a stirring speed of 250 r / min for 20 minutes to transfer the lithium element from the organic phase to the aqueous phase; the lithium-containing aqueous phase and the regenerated extractant are separated by static stratification, and the regenerated extractant can be recycled; Stripping of cobalt and nickel elements: The organic phase containing cobalt and nickel and the stripping agent are added to the stripping reaction kettle in a volume ratio of 1:1.1. The stripping reaction is carried out at 35°C and a stirring speed of 250 r / min for 25 minutes to transfer the cobalt and nickel elements from the organic phase to the aqueous phase. The aqueous phase containing cobalt and nickel and the regenerated extractant are separated by centrifugation, and the regenerated extractant can be recycled. Manganese stripping: The manganese-containing organic phase and the stripping agent are added to a stripping reaction kettle at a volume ratio of 1:1.1. The stripping reaction is carried out at 30°C and a stirring speed of 250 r / min for 20 minutes to transfer the manganese element from the organic phase to the aqueous phase. The manganese-containing aqueous phase and the regenerated extractant are separated by static stratification, and the regenerated extractant can be recycled. (4) Metal recycling: Lithium recovery: The lithium-containing aqueous phase is evaporated and concentrated at 95°C to 1 / 5 of the original solution volume, cooled for crystallization, filtered, washed, and dried to obtain lithium carbonate; Cobalt and nickel element recovery: The aqueous phase containing cobalt and nickel is purified by passing it through a macroporous sulfonic acid styrene-based cation exchange resin to remove impurity ions. Then, metallic cobalt and metallic nickel are obtained at the cathode by electrodeposition at a current density of 17 A / m² and a temperature of 45°C. Manganese recovery: The pH value of the manganese-containing aqueous phase was adjusted to 10 to precipitate manganese ions in the form of manganese hydroxide precipitate. After filtering and washing, the manganese hydroxide precipitate was calcined at 450° C. for 180 min to obtain manganese dioxide.

[0051] The lithium element extractant is a carbonate extractant with a volume fraction of 16%; the carbonate extractant is a mixed solution of dimethyl carbonate and diethyl carbonate with a volume ratio of 1:1.

[0052] The cobalt and nickel element extractant is di-2-ethylhexyl phosphoric acid with a volume fraction of 12%.

[0053] The manganese element extractant is trioctylamine with a volume fraction of 9%.

[0054] The lithium element stripping agent is a hydrochloric acid solution with a mass concentration of 6%.

[0055] The cobalt and nickel element stripping agent is a sulfuric acid solution with a mass concentration of 13%.

[0056] The manganese element stripping agent is a sodium hydroxide solution with a mass concentration of 6%.

[0057] Example 3 The preparation method of the π-π conjugated amphiphilic solubilizing agent specifically comprises the following steps: H1: Heat 35 g vinylferrocene, 400 g anhydrous ethanol, and 50 g triallyl citrate to 75°C and stir to mix; H2: Add 1.5 g of azobisisobutyronitrile as an initiator and react at 85°C for 6 h under a nitrogen atmosphere to generate an amphiphilic coordination salt containing a π-π conjugated structure through free radical polymerization; H3: After the reaction is completed, the ethanol is removed by distillation under reduced pressure, and the mixture is ground into powder to obtain a π-π conjugated amphiphilic solubilizing agent.

[0058] A method for separating and recovering valuable metals from lithium batteries based on multi-stage synergistic extraction, the operating steps of which are as follows: (1) Discharging and dismantling of waste lithium batteries: Place the used lithium batteries in a special discharge device and use the salt water immersion discharge method to completely eliminate the residual power inside the battery; use automated disassembly equipment to disassemble the discharged lithium battery shell and separate the battery shell, electrode material and electrolyte; Electrode material crushing and roasting: The disassembled electrode materials were placed in a crusher and crushed to a particle size of 2 mm. The crushed electrode materials were calcined at 480°C for 110 minutes to remove the organic binder and carbon material in the electrode materials, expose the metal oxides, and increase the leaching rate of metal ions. (2) Multi-stage synergistic extraction: First stage extraction, lithium extraction: 16 g of the calcined electrode material and 85 g of a lithium extraction agent were added to an extraction reactor, and the extraction reaction was carried out at 35°C and a stirring speed of 280 r / min for 25 minutes to transfer the lithium element in the electrode material to the extraction agent, forming a lithium-containing organic phase. After the extraction reaction, the mixture was allowed to stand and separate the lithium-containing organic phase and the raffinate phase. Second stage extraction, extraction of cobalt and nickel elements: 16 g of the raffinate phase after the first stage extraction was added to a new extraction reactor, and 68 g of a cobalt-nickel extractant, 0.4 g of a π-π conjugated amphiphilic solubilizer, and 3 g of kerosene were added. The extraction reaction was carried out at 45°C and a stirring speed of 300 r / min for 35 min to fully extract the cobalt and nickel elements into the organic phase. After the extraction reaction, the organic phase containing cobalt and nickel and the secondary raffinate phase were separated by centrifugation. The third stage of extraction, manganese extraction: 16 g of the secondary raffinate phase after the second stage extraction was added to an extraction reactor, 50 g of a manganese element extractant and 4 g of isooctyl alcohol were added, and the extraction reaction was carried out at 55°C and a stirring speed of 350 r / min for 45 min to extract the manganese element into the organic phase. After the extraction reaction was completed, the manganese-containing organic phase and the final raffinate phase were separated by static stratification. (3) Back extraction: Lithium stripping: The lithium-containing organic phase and the stripping agent are added to a stripping reaction kettle at a volume ratio of 1:1.5, and the stripping reaction is carried out at 30°C and a stirring speed of 250 r / min for 20 minutes to transfer the lithium element from the organic phase to the aqueous phase. The lithium-containing aqueous phase and the regenerated extractant are separated by static stratification, and the regenerated extractant can be recycled. Stripping of cobalt and nickel elements: The organic phase containing cobalt and nickel and the stripping agent are added to the stripping reaction kettle in a volume ratio of 1:1.4, and the stripping reaction is carried out at 35°C and a stirring speed of 250 r / min for 25 minutes to transfer the cobalt and nickel elements from the organic phase to the aqueous phase; the aqueous phase containing cobalt and nickel and the regenerated extractant are separated by centrifugation, and the regenerated extractant can be recycled. Manganese stripping: The manganese-containing organic phase and the stripping agent are added to a stripping reaction kettle at a volume ratio of 1:1.1. The stripping reaction is carried out at 35°C and a stirring speed of 250 r / min for 20 minutes to transfer the manganese element from the organic phase to the aqueous phase. The manganese-containing aqueous phase and the regenerated extractant are separated by static stratification, and the regenerated extractant can be recycled. (4) Metal recycling: Lithium recovery: The lithium-containing aqueous phase is evaporated and concentrated at 95°C to 1 / 5 of the original solution volume, cooled for crystallization, filtered, washed, and dried to obtain lithium carbonate; Cobalt and nickel element recovery: The aqueous phase containing cobalt and nickel is purified by passing it through a macroporous sulfonic acid styrene-based cation exchange resin to remove impurity ions. Then, metallic cobalt and metallic nickel are obtained at the cathode by electrodeposition at a current density of 18 A / m² and a temperature of 45°C. Manganese recovery: The pH value of the manganese-containing aqueous phase was adjusted to 11, so that the manganese ions were precipitated in the form of manganese hydroxide. After filtering and washing, the manganese hydroxide precipitate was calcined at 550° C. for 180 min to obtain manganese dioxide.

[0059] The lithium element extractant is a carbonate extractant with a volume fraction of 18%; the carbonate extractant is a mixed solution of dimethyl carbonate and diethyl carbonate, with a volume ratio of 1:1.

[0060] The cobalt and nickel element extractant is di-2-ethylhexyl phosphoric acid with a volume fraction of 14%.

[0061] The manganese element extractant is trioctylamine with a volume fraction of 11%.

[0062] The lithium element stripping agent is a hydrochloric acid solution with a mass concentration of 8%.

[0063] The cobalt and nickel element stripping agent is a sulfuric acid solution with a mass concentration of 15%.

[0064] The manganese element stripping agent is a sodium hydroxide solution with a mass concentration of 8%.

[0065] Example 4 The preparation method of the π-π conjugated amphiphilic solubilizing agent specifically comprises the following steps: H1: Heat 40 g vinylferrocene, 500 g anhydrous ethanol and 55 g triallyl citrate to 80°C and stir to mix; H2: Add 2 g of initiator azobisisobutyronitrile and react at 90°C for 7 h under a nitrogen atmosphere to generate an amphiphilic coordination salt containing a π-π conjugated structure through free radical polymerization; H3: After the reaction is completed, the ethanol is removed by distillation under reduced pressure, and the mixture is ground into powder to obtain a π-π conjugated amphiphilic solubilizing agent.

[0066] A method for separating and recovering valuable metals from lithium batteries based on multi-stage synergistic extraction, the operating steps of which are as follows: (1) Discharging and dismantling of waste lithium batteries: Place the used lithium batteries in a special discharge device and use the salt water immersion discharge method to completely eliminate the residual power inside the battery; use automated disassembly equipment to disassemble the discharged lithium battery shell and separate the battery shell, electrode material and electrolyte; Electrode material crushing and roasting: The disassembled electrode materials were placed in a crusher and crushed to a particle size of 1 mm. The crushed electrode materials were calcined at 500°C for 120 minutes to remove the organic binder and carbon material in the electrode materials, expose the metal oxides, and increase the leaching rate of metal ions. (2) Multi-stage synergistic extraction: First stage extraction, lithium extraction: 18 g of the calcined electrode material and 90 g of a lithium extraction agent were added to an extraction reactor, and the extraction reaction was carried out at 40°C and a stirring speed of 300 r / min for 30 min. The lithium element in the electrode material was transferred to the extraction agent to form a lithium-containing organic phase. After the extraction reaction was completed, the mixture was allowed to stand for stratification to separate the lithium-containing organic phase and the raffinate phase. Second stage extraction, extraction of cobalt and nickel elements: 18 g of the raffinate phase after the first stage extraction was added to a new extraction reactor, and 72 g of a cobalt-nickel extractant, 0.5 g of a π-π conjugated amphiphilic solubilizer, and 4 g of kerosene were added. The extraction reaction was carried out at 50°C and a stirring speed of 350 r / min for 40 min to fully extract the cobalt and nickel elements into the organic phase. After the extraction reaction, the organic phase containing cobalt and nickel and the secondary raffinate phase were separated by centrifugation. The third stage of extraction, manganese extraction: 18 g of the secondary raffinate phase after the second stage extraction was added to an extraction reactor, and 54 g of a manganese element extractant and 5 g of isooctyl alcohol were added. The extraction reaction was carried out at 60°C and a stirring speed of 400 r / min for 50 min to extract the manganese element into the organic phase. After the extraction reaction was completed, the manganese-containing organic phase and the final raffinate phase were separated by standing and stratification. (3) Back extraction: Lithium stripping: The lithium-containing organic phase and the stripping agent are added to the stripping reactor in a volume ratio of 1:2. The stripping reaction is carried out at 30°C and a stirring speed of 300 r / min for 25 minutes to transfer the lithium element from the organic phase to the aqueous phase. The lithium-containing aqueous phase and the regenerated extractant are separated by static stratification, and the regenerated extractant can be recycled. Stripping of cobalt and nickel elements: The organic phase containing cobalt and nickel and the stripping agent are added to a stripping reactor in a volume ratio of 1:1.5. The stripping reaction is carried out at 40°C and a stirring speed of 300 r / min for 30 minutes to transfer the cobalt and nickel elements from the organic phase to the aqueous phase. The aqueous phase containing cobalt and nickel and the regenerated extractant are separated by centrifugation, and the regenerated extractant can be recycled. Manganese stripping: The manganese-containing organic phase and the stripping agent are added to the stripping reaction kettle in a volume ratio of 1:1.2. The stripping reaction is carried out at 35°C and a stirring speed of 300 r / min for 25 minutes to transfer the manganese element from the organic phase to the aqueous phase. The manganese-containing aqueous phase and the regenerated extractant are separated by static stratification, and the regenerated extractant can be recycled. (4) Metal recycling: Lithium recovery: The lithium-containing aqueous phase is evaporated and concentrated at 100° C. to 1 / 5 of the original solution volume, cooled and crystallized, filtered, washed, and dried to obtain lithium carbonate; Cobalt and nickel element recovery: The aqueous phase containing cobalt and nickel is purified by passing it through a macroporous sulfonic acid styrene-based cation exchange resin to remove impurity ions. Then, metallic cobalt and metallic nickel are obtained at the cathode by electrodeposition at a current density of 20 A / m² and a temperature of 50°C. Manganese recovery: The pH value of the manganese-containing aqueous phase was adjusted to 11, so that the manganese ions were precipitated in the form of manganese hydroxide. After filtering and washing, the manganese hydroxide precipitate was calcined at 600° C. for 180 min to obtain manganese dioxide.

[0067] The lithium element extractant is a carbonate extractant with a volume fraction of 20%; the carbonate extractant is a mixed solution of dimethyl carbonate and diethyl carbonate, with a volume ratio of 1:1.

[0068] The cobalt and nickel element extractant is di-2-ethylhexyl phosphoric acid with a volume fraction of 15%.

[0069] The manganese element extractant is trioctylamine with a volume fraction of 12%.

[0070] The lithium element stripping agent is a hydrochloric acid solution with a mass concentration of 10%.

[0071] The cobalt and nickel element stripping agent is a sulfuric acid solution with a mass concentration of 20%.

[0072] The manganese element stripping agent is a sodium hydroxide solution with a mass concentration of 10%.

[0073] Comparative Example 1 A method for separating and recovering valuable metals from lithium batteries based on multi-stage synergistic extraction, without using a π-π conjugated amphiphilic solubilizing agent, comprises the following steps: (1) Discharging and dismantling of waste lithium batteries: Place the used lithium batteries in a special discharge device and use the salt water immersion discharge method to completely eliminate the residual power inside the battery; use automated disassembly equipment to disassemble the discharged lithium battery shell and separate the battery shell, electrode material and electrolyte; Electrode material crushing and roasting: The disassembled electrode materials were placed in a crusher and crushed to a particle size of 3 mm. The crushed electrode materials were calcined at 400°C for 90 minutes to remove the organic binder and carbon material in the electrode materials, expose the metal oxides, and increase the leaching rate of metal ions. (2) Multi-stage synergistic extraction: First stage extraction, lithium extraction: 12 g of the calcined electrode material and 70 g of a lithium extraction agent were added to an extraction reactor, and the extraction reaction was carried out at 30°C and a stirring speed of 200 r / min for 20 minutes. The lithium element in the electrode material was transferred to the extraction agent to form a lithium-containing organic phase. After the extraction reaction was completed, the mixture was allowed to stand for stratification to separate the lithium-containing organic phase and the raffinate phase. Second stage extraction, extraction of cobalt and nickel elements: 12 g of the raffinate phase after the first stage extraction was added to a new extraction reactor, and 56 g of a cobalt-nickel extractant and 1 g of kerosene were added. The extraction reaction was carried out at 40°C and a stirring speed of 250 r / min for 30 min to fully extract the cobalt and nickel elements into the organic phase. After the extraction reaction, the organic phase containing cobalt and nickel and the secondary raffinate phase were separated by centrifugation. The third stage of extraction, manganese extraction: 12 g of the secondary raffinate phase after the second stage extraction was added to an extraction reactor, 36 g of a manganese element extractant and 1 g of isooctyl alcohol were added, and the extraction reaction was carried out at 50°C and a stirring speed of 300 r / min for 40 min to extract the manganese element into the organic phase. After the extraction reaction was completed, the manganese-containing organic phase and the final raffinate phase were separated by static stratification. (3) Back extraction: Lithium stripping: The lithium-containing organic phase and the stripping agent are added to the stripping reactor in a volume ratio of 1:1. The stripping reaction is carried out at 25°C and a stirring speed of 200 r / min for 15 minutes to transfer the lithium element from the organic phase to the aqueous phase. The lithium-containing aqueous phase and the regenerated extractant are separated by static stratification, and the regenerated extractant can be recycled. Stripping of cobalt and nickel elements: The organic phase containing cobalt and nickel and the stripping agent are added to a stripping reactor in a volume ratio of 1:1. The stripping reaction is carried out at 30°C and a stirring speed of 200 r / min for 20 minutes to transfer the cobalt and nickel elements from the organic phase to the aqueous phase. The aqueous phase containing cobalt and nickel and the regenerated extractant are separated by centrifugation, and the regenerated extractant can be recycled. Manganese stripping: The manganese-containing organic phase and the stripping agent are added to the stripping reaction kettle in a volume ratio of 1:1. The stripping reaction is carried out at 30°C and a stirring speed of 200 r / min for 15 minutes to transfer the manganese element from the organic phase to the aqueous phase. The manganese-containing aqueous phase and the regenerated extractant are separated by static stratification, and the regenerated extractant can be recycled. (4) Metal recycling: Lithium recovery: The lithium-containing aqueous phase is evaporated and concentrated at 90°C to 1 / 5 of the original solution volume, cooled for crystallization, filtered, washed, and dried to obtain lithium carbonate; Cobalt and nickel element recovery: The aqueous phase containing cobalt and nickel is purified by passing it through a macroporous sulfonic acid styrene-based cation exchange resin to remove impurity ions. Then, metallic cobalt and metallic nickel are obtained at the cathode by electrodeposition at a current density of 16 A / m² and a temperature of 40°C. Manganese recovery: The pH value of the manganese-containing aqueous phase was adjusted to 10 to precipitate manganese ions in the form of manganese hydroxide precipitate. After filtering and washing, the manganese hydroxide precipitate was calcined at 400° C. for 180 min to obtain manganese dioxide.

[0074] The lithium element extractant is a carbonate extractant with a volume fraction of 15%; the carbonate extractant is a mixed solution of dimethyl carbonate and diethyl carbonate with a volume ratio of 1:1.

[0075] The cobalt and nickel element extractant is di-2-ethylhexyl phosphoric acid with a volume fraction of 10%.

[0076] The manganese element extractant is trioctylamine with a volume fraction of 8%.

[0077] The lithium element stripping agent is a hydrochloric acid solution with a mass concentration of 5%.

[0078] The cobalt-nickel element stripping agent is a sulfuric acid solution with a mass concentration of 10%.

[0079] The manganese element stripping agent is a sodium hydroxide solution with a mass concentration of 5%.

[0080] Test Example 1 The recoveries of lithium, cobalt, nickel and manganese in the examples and comparative examples were tested by inductively coupled plasma atomic emission spectrometry. The test results are shown in Table 1.

[0081] Table 1

[0082] Through the data analysis of the above embodiments and comparative examples, the lithium recovery rate of the present invention can reach more than 97%, and the recovery rates of cobalt, nickel and manganese can all reach more than 93%, effectively improving resource utilization.

[0083] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for separating and recovering valuable metals from lithium batteries based on multi-stage synergistic extraction, characterized in that: Calculated by mass, the method comprises the following steps: (1) Discharge and disassemble the waste lithium batteries to obtain the battery shell, electrode materials and electrolyte, and crush and roast the electrode materials; (2) Multi-stage extraction: 12-18 parts of calcined electrode material and 70-90 parts of lithium element extractant are used for extraction reaction to separate the lithium-containing organic phase and the raffinate phase to complete the first stage extraction; An extraction reaction is carried out using 12-18 parts of the raffinate phase after the first stage extraction, 56-72 parts of a cobalt-nickel element extractant, 0.1-0.5 parts of a π-π conjugated amphiphilic solubilizer, and 1-4 parts of kerosene to separate an organic phase containing cobalt and nickel and a secondary raffinate phase, thereby completing the second stage extraction; An extraction reaction is carried out using 12-18 parts of the raffinate phase after the second stage extraction, 36-54 parts of a manganese extractant, and 1-5 parts of isooctyl alcohol to separate the manganese-containing organic phase and the final raffinate phase, thereby completing the third stage extraction; (3) The organic phase containing lithium, the organic phase containing cobalt and nickel, and the organic phase containing manganese are stripped and separated, and the separated valuable metal aqueous phase is subjected to metal recovery to obtain lithium carbonate, metallic cobalt, metallic nickel, and manganese dioxide, respectively.

2. The method for separating and recovering valuable metals from lithium batteries based on multi-stage synergistic extraction according to claim 1, characterized in that: The calcination temperature in step (1) is 400-500°C, and the calcination time is 90-120 min.

3. The method for separating and recovering valuable metals from lithium batteries based on multi-stage synergistic extraction according to claim 1, characterized in that: In step (2), the temperature of the first stage extraction is 30-40°C, the stirring speed is 200-300 r / min, and the extraction reaction time is 20-30 min; The temperature of the second stage extraction is 40-50℃, the stirring speed is 250-350 r / min, and the extraction reaction time is 30-40min; The temperature of the third stage extraction is 50-60°C, the stirring speed is 300-400 r / min, and the extraction reaction time is 40-50 minutes.

4. The method for separating and recovering valuable metals from lithium batteries based on multi-stage synergistic extraction according to claim 1, characterized in that: In step (2), the preparation method of the π-π conjugated amphiphilic solubilizing agent comprises the following steps, calculated by weight: 20-40 parts of vinylferrocene and 27-55 parts of triallyl citrate are uniformly dispersed in a solvent; Add 0.3-2 parts of initiator and induce free radical polymerization reaction under inert atmosphere to generate amphiphilic coordination salt containing π-π conjugated structure; After the reaction is completed, the solvent is removed to obtain a π-π conjugated amphiphilic solubilizing agent.

5. The method for separating and recovering valuable metals from lithium batteries based on multi-stage synergistic extraction according to claim 4, characterized in that: The solvent is anhydrous ethanol, with a mass fraction of 200-500 parts; when dispersing, stir and mix at a temperature of 70-80°C to disperse evenly; The initiator is azobisisobutyronitrile.

6. The method for separating and recovering valuable metals from lithium batteries based on multi-stage synergistic extraction according to claim 1, characterized in that: In step (2), the volume ratio of carbonates in the lithium extractant is 15%-20%, wherein the carbonates include dimethyl carbonate and diethyl carbonate, and the volume ratio of dimethyl carbonate to diethyl carbonate is 1:1; The volume proportion of di-2-ethylhexyl phosphoric acid in the cobalt and nickel element extractant is 10%-15%; The volume proportion of trioctylamine in the manganese element extractant is 8%-12%.

7. The method for separating and recovering valuable metals from lithium batteries based on multi-stage synergistic extraction according to claim 1, characterized in that: In step (3), the lithium-containing organic phase is stripped and separated, comprising: uniformly mixing the lithium-containing organic phase and a lithium element stripping agent in a volume ratio of 1:1-2, performing a stripping reaction for 15-25 minutes at 25-30° C. and a stirring speed of 200-300 r / min, and separating the lithium-containing aqueous phase and the lithium element regeneration extractant; Stripping and separating the organic phase containing cobalt and nickel, comprising: uniformly mixing the organic phase containing cobalt and nickel and a cobalt-nickel stripping agent at a volume ratio of 1:1-1.5, performing a stripping reaction at 30-40° C. and a stirring speed of 200-300 r / min for 20-30 minutes, and separating an aqueous phase containing cobalt and nickel and a cobalt-nickel regeneration extractant; The manganese-containing organic phase is subjected to back extraction and separation, comprising: uniformly mixing the manganese-containing organic phase and a manganese element back extraction agent in a volume ratio of 1:1-1.2, performing a back extraction reaction for 15-25 minutes at 30-35° C. and a stirring speed of 200-300 r / min, and separating a manganese-containing aqueous phase and a manganese element regeneration extraction agent.

8. The method for separating and recovering valuable metals from lithium batteries based on multi-stage synergistic extraction according to claim 7, characterized in that: The lithium stripping agent is a hydrochloric acid solution with a mass concentration of 5%-10%; The cobalt and nickel stripping agent is a sulfuric acid solution with a mass concentration of 10%-20%; The manganese element stripping agent is a sodium hydroxide solution with a mass concentration of 5%-10%.

9. The method for separating and recovering valuable metals from lithium batteries based on multi-stage synergistic extraction according to claim 1, characterized in that: In step (3), the separated valuable metal aqueous phase is subjected to metal recovery, comprising: A lithium-containing aqueous phase, after removing the aqueous phase, obtains lithium carbonate; The aqueous phase containing cobalt and nickel is passed through a macroporous sulfonic acid styrene-based cation exchange resin and then combined with an electrodeposition method to obtain metallic cobalt and metallic nickel, wherein the electrodeposition current density is 16-20 A / m² and the temperature is 40-50°C; The pH value of the manganese-containing aqueous phase is adjusted to 10-11 to precipitate manganese hydroxide, which is then calcined to obtain manganese dioxide, wherein the calcination temperature is 400-600°C.

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