Method for lithium-aluminum-sodium-fluorine cooperative recovery and material circulation in lithium-containing waste aluminum electrolyte

Abstract

This invention relates to a method for the synergistic recovery and material recycling of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolytes. The core innovation lies in the first step: using a sodium carbonate solution of a specific concentration at an optimized temperature, only lithium in the lithium-containing phase is selectively leached, while aluminum and fluorine are largely retained in the residue. This not only achieves efficient lithium separation but also creates pure raw material conditions for the subsequent independent recovery of aluminum and fluorine. Combined with internal material recycling, the entire process is green, low-carbon, and highly economical. This invention achieves multi-element synergistic recovery and process simplification, constructing a dual-efficiency internal recycling system with significant environmental and economic benefits.

Description

Technical Field

[0001] This invention belongs to the field of non-ferrous metal metallurgy and resource recycling technology, specifically relating to a clean production method for efficiently and synergistically extracting valuable elements such as lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolyte generated in the aluminum electrolysis industry, and realizing closed-loop recycling of leached materials. Background Technology

[0002] With the rapid development of the lithium-ion battery industry, the demand for lithium resources has surged. In the aluminum electrolysis industry, lithium-containing additives introduced to optimize the electrolysis process have made waste electrolytes an important potential secondary lithium resource. Lithium-containing waste aluminum electrolytes have a complex composition, with lithium-containing phases mainly consisting of lithium cryolite (Li3AlF6) and sodium-lithium cryolite (Na2LiAlF6), while also containing cryolite (Na3AlF6), aluminum fluoride (AlF3), and alumina (Al2O3), etc. They are classified as hazardous solid waste, making resource recovery and treatment difficult.

[0003] Currently, the main methods for recovering lithium from this waste include roasting-leaching and acid leaching. For example, CN113718107A discloses a method for efficiently extracting lithium and preparing anhydrous aluminum fluoride from lithium-rich aluminum electrolyte waste residue, and CN114438329A discloses a comprehensive recovery method for waste lithium-containing aluminum electrolyte. However, the existing technologies generally have the following prominent problems: (1) poor selectivity: although acid leaching can efficiently leach lithium, it also leads to the dissolution of large amounts of aluminum and fluorine elements, resulting in complex composition of the leachate, which seriously interferes with the subsequent deep separation and purification of lithium; (2) the process focuses on the recovery of a single element and fails to achieve the synergistic high-value utilization of lithium, aluminum, fluorine and sodium, resulting in low comprehensive resource benefits; (3) a large amount of fluorine-containing waste liquid or waste residue is generated, and the environmental treatment cost is high; (4) most chemical reagents are consumed once and lack effective internal circulation design, resulting in high production costs.

[0004] Therefore, developing a green and efficient integrated process that can selectively leach lithium, synergistically recover multiple elements, and construct a closed-loop cycle for key reagents has significant industrial application value. Summary of the Invention

[0005] In view of the current state of the prior art, especially the poor selectivity of acid leaching, the purpose of this invention is to provide a method for the synergistic recovery and material recycling of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolytes. This invention designs an integrated process of "selective lithium leaching with sodium carbonate—causticization-regenerated alkali—alkali leaching recovery of aluminum and fluorine—carbonization precipitation closed-loop circulation." Its core innovation lies in the first step: using a sodium carbonate solution of a specific concentration at an optimized temperature, only lithium is selectively leached from the lithium-containing phase, while aluminum and fluorine are essentially not leached and remain in the residue. This not only achieves efficient lithium separation but also creates pure raw material conditions for the subsequent independent recovery of aluminum and fluorine. Combined with internal material recycling, it achieves a green, low-carbon, and highly economical process throughout.

[0006] The technical solution for achieving the above-mentioned objectives can be summarized as follows:

[0007] A method for the synergistic recovery of lithium, aluminum, sodium, and fluorine and reagent recycling from lithium-containing waste aluminum electrolyte includes the following steps:

[0008] S1. Selective leaching of lithium with sodium carbonate: The lithium-containing waste aluminum electrolyte is crushed and ground, then mixed with a sodium carbonate solution with a concentration of 0.1-4.6 mol / L, and leached with stirring at a temperature of 80-300℃; after leaching, solid-liquid separation is performed to obtain a leachate containing only lithium and sodium and a leaching residue rich in aluminum and fluorine.

[0009] S2. Deep separation and enrichment of lithium: The lithium-containing leachate obtained in step S1 is separated and enriched by adsorption or solvent extraction to obtain a high-concentration refined lithium solution and a loaded sodium carbonate solution.

[0010] S3. Sodium carbonate regeneration and alkali conversion: The loaded sodium carbonate solution obtained in step S2 is subjected to a causticization reaction with calcium oxide. After the reaction is complete, the solid and liquid are separated to obtain solid calcium carbonate and sodium hydroxide solution.

[0011] S4. Calcium oxide recycling and aluminum-fluorine extraction: The calcium carbonate obtained in step S3 is calcined and decomposed to regenerate calcium oxide, which is then recycled back to step S3. At the same time, the sodium hydroxide solution obtained in step S3 is used to leach the leaching residue produced in step S1. An alkaline leaching reaction is carried out, and after the reaction, solid and liquid are separated to obtain sodium hydroxide leachate containing sodium aluminate and sodium fluoride and final tailings.

[0012] S5. Aluminum-fluorine precipitation and closed-loop circulation of sodium carbonate: Carbon dioxide is introduced into the sodium hydroxide leaching solution obtained in step S4 to carry out carbonation and stepwise precipitation. First, the conditions are controlled to precipitate aluminum and fluorine in the form of cryolite. After filtration, cryolite product is obtained. The resulting filtrate is a crude sodium carbonate solution and is returned to step S1 as part of the preparation of sodium carbonate leaching solution to realize the closed-loop circulation of sodium carbonate.

[0013] According to the present invention, preferably, the particle size of the lithium-containing waste aluminum electrolyte in S1 is less than 100 mesh;

[0014] Preferably, the liquid-to-solid ratio during sodium carbonate leaching in S1 is (3-10):1mL / g; preferably, the leaching time in S1 is 0.5-6 hours.

[0015] According to the present invention, preferably, the concentration of sodium carbonate solution in S1 is 3.5-4.2 mol / L, and the leaching temperature is 180-220℃.

[0016] According to the present invention, preferably, the adsorbent used in the adsorption method in S2 is a manganese-based or titanium-based lithium-ion sieve; the extraction system used in the solvent extraction method is a tributyl phosphate (TBP)-FeCl3 co-extraction system.

[0017] According to the present invention, preferably, the amount of calcium oxide added in the causticizing reaction in S3 is controlled according to the stoichiometric ratio of CaO:Na2CO3 as (1.0-1.2):1;

[0018] Preferably, the causticizing reaction temperature in S3 is 60-95℃, and the reaction time is 0.5-2 hours.

[0019] According to the present invention, preferably, the calcination temperature of calcium carbonate in S4 is 800-1000°C and the calcination time is 1-3 hours;

[0020] Preferably, when leaching the residue with sodium hydroxide solution in S4, the leaching temperature is 90-150℃ and the leaching time is 0.5-6 hours.

[0021] According to the present invention, preferably, the carbonization precipitation in S5 is achieved by controlling the rate of CO2 introduction and the pH at the reaction endpoint to achieve preferential precipitation of cryolite; preferably, the pH at the carbonization precipitation endpoint in S5 is controlled at 9-11.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. Selective Lithium Leaching: This invention achieves selective leaching of lithium under optimized conditions using a sodium carbonate system, extracting only lithium and avoiding aluminum and fluorine. This avoids interference from aluminum and fluorine ions in the lithium extraction process from the source, resulting in more efficient and simpler subsequent lithium separation processes (adsorption or extraction) and superior product purity.

[0024] 2. Multi-element synergistic recovery and process simplification: After lithium is preferentially and cleanly separated, aluminum and fluorine are efficiently recovered as cryolite products in independent alkaline leaching-carbonization steps. The process of this invention avoids the complex separation problems caused by co-leaching in traditional processes.

[0025] 3. A dual-efficiency internal circulation system is constructed: The system of this invention includes two key material cycles: first, a closed-loop sodium carbonate cycle, in which the crude sodium carbonate solution, a byproduct of carbonation, is returned to the leaching process for recycling, thereby significantly reducing the consumption of fresh sodium carbonate; second, a calcium oxide / calcium carbonate cycle, in which the calcium carbonate produced in the causticizing process is calcined and regenerated into calcium oxide, which is then reused in the process, forming a complete calcium cycle. This dual-circulation design reduces reagent costs and solid waste generation from the source.

[0026] 4. Significant environmental and economic benefits: Selective leaching eliminates the generation of fluoride-containing acidic wastewater at the source; the internal circulation of materials greatly reduces operating costs; and at the same time, it produces high-value refined lithium liquid and cryolite, making the treatment of low-grade lithium-containing waste highly economically feasible. Attached Figure Description

[0027] Figure 1 This is a process flow diagram of the method for synergistic recovery and reagent recycling of lithium, aluminum, sodium and fluorine in lithium-containing waste aluminum electrolytes according to the present invention.

[0028] Figure 2 The image shows the XRD pattern of the lithium-containing waste aluminum electrolyte raw material in Example 1.

[0029] Figure 3 The image shows the XRD pattern of the cryolite product obtained in Example 1. Detailed Implementation

[0030] This invention provides a method for the synergistic recovery and recycling of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolytes. The core innovation lies in the first step: using a sodium carbonate solution of a specific concentration at an optimized temperature, lithium is selectively leached from the lithium-containing phases (Li3AlF6 and Na2LiAlF6), while aluminum and fluorine are largely retained in the residue. This not only achieves efficient lithium separation but also creates pure raw material conditions for the subsequent independent recovery of aluminum and fluorine. Combined with internal reagent recycling, the entire process is green, low-carbon, and highly economical.

[0031] The present invention discloses a method for the synergistic recovery and recycling of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolyte, comprising the following steps:

[0032] S1. Selective leaching of lithium with sodium carbonate: The lithium-containing waste aluminum electrolyte is crushed and ground, then mixed with a sodium carbonate solution with a concentration of 0.1-4.6 mol / L, and leached with stirring at a temperature of 80-300℃; after leaching, solid-liquid separation is performed to obtain a leachate containing only lithium and sodium and a leaching residue rich in aluminum and fluorine.

[0033] S2. Deep separation and enrichment of lithium: The lithium-containing leachate obtained in step S1 is separated and enriched by adsorption or solvent extraction to obtain a high-concentration refined lithium solution and a loaded sodium carbonate solution.

[0034] S3. Sodium carbonate regeneration and alkali conversion: The loaded sodium carbonate solution obtained in step S2 is subjected to a causticization reaction with calcium oxide. After the reaction is complete, the solid and liquid are separated to obtain solid calcium carbonate and sodium hydroxide solution.

[0035] S4. Calcium oxide recycling and aluminum-fluorine extraction: The calcium carbonate obtained in step S3 is calcined and decomposed to regenerate calcium oxide, which is then recycled back to step S3. At the same time, the sodium hydroxide solution obtained in step S3 is used to leach the leaching residue produced in step S1. An alkaline leaching reaction is carried out, and after the reaction, solid and liquid are separated to obtain sodium hydroxide leachate containing sodium aluminate and sodium fluoride and final tailings.

[0036] S5. Aluminum-fluorine precipitation and closed-loop circulation of sodium carbonate: Carbon dioxide is introduced into the sodium hydroxide leaching solution obtained in step S4 for carbonation and stepwise precipitation. First, the conditions are controlled to precipitate aluminum and fluorine in the form of cryolite (Na3AlF6). After filtration, cryolite product is obtained. The resulting filtrate is a crude sodium carbonate solution, which is returned to step S1 as part of the preparation of sodium carbonate leaching solution to realize the closed-loop circulation of sodium carbonate.

[0037] According to the present invention, in the sodium carbonate solution of a specific concentration in S1, at an optimized temperature, sodium carbonate preferentially undergoes a metathesis reaction with lithium-containing phases Li3AlF6 and Na2LiAlF6. Lithium enters the solution in the form of soluble lithium carbonate (Li2CO3), while aluminum and fluorine elements are converted into insoluble aluminum fluoride (AlF3) or retained in the cryolite (Na3AlF6) structure and are effectively fixed in the residue, thereby achieving source separation of lithium from aluminum and fluorine.

[0038] In one or more preferred embodiments, the sodium carbonate solution concentration in S1 is 3.5-4.2 mol / L, and the leaching temperature is 180-220°C. These optimized conditions enable the most efficient leaching of lithium with almost no leaching of aluminum and fluorine.

[0039] In one or more preferred embodiments, the liquid-to-solid ratio during sodium carbonate leaching in S1 is (3-10):1 mL / g; preferably, the leaching time in S1 is 0.5-6 hours. Preferably, the particle size of the lithium-containing waste aluminum electrolyte in S1 is less than 100 mesh.

[0040] According to the present invention, lithium is separated and enriched in step S2 using adsorption or solvent extraction to obtain a high-concentration refined lithium solution and a loaded sodium carbonate solution. The loaded sodium carbonate solution is the sodium carbonate solution obtained after the leaching reaction in step S1. The refined lithium solution obtained in step S2 can be used to prepare products such as lithium carbonate and lithium fluoride.

[0041] In one or more preferred embodiments, the adsorbent used in the adsorption method in S2 is a manganese-based or titanium-based lithium-ion sieve; the extraction system used in the solvent extraction method is a tributyl phosphate (TBP)-FeCl3 co-extraction system.

[0042] According to the present invention, the S3 causticization reaction achieves sodium-alkali conversion, transforming sodium carbonate into sodium hydroxide. In one or more preferred embodiments, the amount of calcium oxide added in the S3 causticization reaction is controlled according to a stoichiometric ratio of CaO:Na2CO3 of (1.0-1.2):1. Preferably, the causticization reaction temperature in S3 is 60-95°C, and the reaction time is 0.5-2 hours.

[0043] According to the present invention, calcium oxide recycling and aluminum-fluorine extraction are realized in S4. The calcium carbonate obtained in S3 is calcined and decomposed to regenerate calcium oxide, which is then returned to step S3 for recycling. At the same time, the sodium hydroxide solution obtained in step S3 is used to leach the leaching residue generated in step S1 to carry out an alkaline leaching reaction. After the reaction, solid and liquid are separated to obtain sodium hydroxide leachate containing sodium aluminate and sodium fluoride and final tailings.

[0044] In one or more preferred embodiments, the calcination temperature of calcium carbonate in S4 is 800-1000°C, and the calcination time is 1-3 hours.

[0045] In one or more preferred embodiments, when leaching the residue with sodium hydroxide solution in S4, the leaching temperature is 90-150°C and the leaching time is 0.5-6 hours.

[0046] According to the present invention, the carbonization process in S5 recovers the aluminum and fluorine leached from the residue in the form of cryolite and regenerates sodium carbonate.

[0047] In one or more preferred embodiments, the carbonization precipitation in S5 achieves preferential precipitation of cryolite by controlling the rate of CO2 introduction and the final pH of the reaction. Preferably, the final pH of the carbonization precipitation in S5 is controlled between 9 and 11.

[0048] The reaction mechanism of this invention is summarized as follows:

[0049] In S1, sodium carbonate preferentially undergoes a metathesis reaction with lithium-containing phases Li3AlF6 and Na2LiAlF6. Lithium enters the solution in the form of soluble lithium carbonate (Li2CO3), while aluminum and fluorine are converted into insoluble aluminum fluoride (AlF3) or retained in the cryolite (Na3AlF6) structure and effectively fixed in the residue, thus achieving source separation of lithium from aluminum and fluorine.

[0050]

[0051] In S3, the causticization reaction achieves the transformation of sodium alkali.

[0052]

[0053] In S5, the carbonization process recovers the aluminum and fluorine leached from the residue in the form of cryolite and regenerates sodium carbonate.

[0054]

[0055] The present invention will be further described below through specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0056] The lithium-containing waste aluminum electrolyte raw material used in the examples was analyzed by XRD (e.g. Figure 2 As shown in the figure, its main lithium-containing phases are Li3AlF6 and Na2LiAlF6, and it also contains Na3AlF6, AlF3, etc.

[0057] Example 1

[0058] A method for the synergistic recovery and recycling of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolytes includes the following steps:

[0059] S1. Selective leaching of lithium with sodium carbonate: 200g of raw material crushed to -150 mesh was added to a high-pressure reactor along with 1000mL of 2.0mol / L Na₂CO₃ solution, and leaching was carried out at 150℃ with stirring for 4 hours. The solution was filtered while hot to obtain the leachate and residue. Analysis showed that the lithium leaching rate from Li₃AlF₆ and Na₂LiAlF₆ reached 65.5%, while the leaching rate of aluminum was <0.5% and the leaching rate of fluorine was <0.3%, achieving highly selective lithium leaching.

[0060] S2. Lithium extraction by adsorption: The leachate has a simple composition (mainly containing Li⁺, Na⁺, and CO₃²⁻). 2 (⁻), after adsorption through a titanium-based lithium ion sieve and acid desorption, a high-purity refined lithium solution is obtained. The adsorption tail liquid is a loaded Na₂CO₃ solution.

[0061] S3, Causticization transformation: The above tail liquid is reacted with CaO (molar ratio CaO:Na2CO3=1.05:1) at 80℃ for 1.5 hours, and filtered to obtain NaOH solution and CaCO3 filter cake.

[0062] S4. Calcination and Alkali Leaching: The CaCO3 filter cake was calcined at 900℃ for 2 hours to regenerate active CaO for later use. The residue from S1 (rich in Al and F) was alkali-leached with the obtained NaOH solution at 90℃ for 4 hours, and the alkali leaching solution and final tailings were obtained by filtration.

[0063] S5. Carbonization Precipitation and Closed-Loop Circulation: CO2-containing kiln gas is introduced into the alkaline leaching solution to control the pH to approximately 10.5. Filtration yields high-quality cryolite product (XRD pattern as shown). Figure 3 As shown, Figure 3 The solution was displayed as pure phase Na3AlF6. The filtrate was a crude Na2CO3 solution. After adding a small amount of fresh alkali to adjust the concentration, it was returned to S1 for recycling.

[0064] Example 2: Verification of Optimal Conditions

[0065] A method for the synergistic recovery and recycling of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolytes includes the following steps:

[0066] S1. Selective leaching of lithium with sodium carbonate: 200g of the same raw material and 1000mL of 4.0mol / L Na2CO3 solution were added to a high-pressure reactor and leached with stirring at 200℃ for 3 hours. These conditions are within the preferred concentration and temperature range of this invention. Post-leaching analysis showed that the lithium leaching rate was significantly increased to 97.8%, while the aluminum leaching rate was <0.2% and the fluorine leaching rate was <0.2%, achieving optimal selective leaching effect.

[0067] S2. Lithium extraction by extraction: The pure leachate obtained in S1 is extracted using a TBP-FeCl3 co-extraction system to efficiently obtain refined lithium liquid.

[0068] S3-S5: The subsequent steps are the same as in Example 1, and each step operates stably.

[0069] This embodiment demonstrates that by using the preferred leaching parameters of the present invention, lithium can be recovered to its maximum extent without leaching aluminum and fluorine at almost no rate.

[0070] Comparative example, traditional sulfuric acid leaching method

[0071] To highlight the absolute advantage of selective leaching in this invention, the same raw material was treated using the traditional sulfuric acid method: 200g of raw material was weighed and mixed with 1000mL of 2.0mol / L H2SO4 solution, and leached at 90℃ for 3 hours. The results showed that the lithium leaching rate was 96%, but the aluminum leaching rate was >95%, and the fluorine leaching rate was >92%. The resulting leachate had an extremely complex composition, making subsequent lithium separation and extraction extremely difficult and costly, and generating a large amount of fluoride-containing acidic wastewater that required treatment.

[0072] Test case

[0073] To verify the selective leaching effect and overall element recovery efficiency of the process of this invention, the following tests and material balance calculations were performed.

[0074] 1. Selectivity verification of the sodium carbonate leaching system

[0075] The effects of sodium carbonate concentration and leaching temperature on the leaching behavior of lithium, aluminum, and fluorine were systematically investigated. Specific data are shown in Table 1.

[0076] Table 1: Leaching rates of various elements at different sodium carbonate concentrations

[0077]

[0078] As shown in Table 1, throughout the tested concentration range (1.0-4.6 mol / L), the leaching rates of aluminum and fluorine remained consistently below 0.8% and 0.5%, respectively, indicating that they were essentially not leached. Conversely, the leaching rate of lithium increased significantly with increasing sodium carbonate concentration. Particularly under the preferred conditions of this invention (3.5-4.2 mol / L, 180-220℃), the lithium leaching rate exceeded 95%, while the leaching rates of aluminum and fluorine were both below 0.3%. These data fully demonstrate that the sodium carbonate solution used in this invention exhibits a highly selective leaching capability for lithium, enabling efficient source separation of lithium from aluminum and fluorine.

[0079] 2. Evaluation of element recovery rate throughout the entire process

[0080] Based on the above-mentioned preferred leaching conditions (3.5-4.2 mol / L, 180-220℃), the complete process flow of the present invention was run and material balance was performed. The recovery rates of key elements were as follows: from raw materials to refined lithium liquid, the total recovery rate of lithium was greater than 95%, and the total recovery rate of aluminum and fluorine from leaching residue to final cryolite product was greater than 90%.

[0081] The above examples and experimental data fully demonstrate that the integrated process of "selective leaching of sodium carbonate - reagent recycling" provided by this invention can efficiently, cleanly, and economically achieve the synergistic recovery of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolytes. In particular, when using optimized leaching conditions of 3.5-4.2 mol / L sodium carbonate concentration and 180-220℃, it exhibits excellent lithium selective extraction performance. Furthermore, by constructing a dual-cycle system of sodium carbonate and calcium oxide, green and low-carbon production is achieved, demonstrating significant prospects for industrial application.

Claims

1. A method for the synergistic recovery and reagent recycling of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolyte, comprising the following steps: S1. Selective leaching of lithium with sodium carbonate: The lithium-containing waste aluminum electrolyte is crushed and ground, then mixed with a sodium carbonate solution with a concentration of 0.1-4.6 mol / L, and leached with stirring at a temperature of 80-300℃; after leaching, solid-liquid separation is performed to obtain a leachate containing only lithium and sodium and a leaching residue rich in aluminum and fluorine. S2. Deep separation and enrichment of lithium: The lithium-containing leachate obtained in step S1 is separated and enriched by adsorption or solvent extraction to obtain a high-concentration refined lithium solution and a loaded sodium carbonate solution. S3. Sodium carbonate regeneration and alkali conversion: The loaded sodium carbonate solution obtained in step S2 is subjected to a causticization reaction with calcium oxide. After the reaction is complete, the solid and liquid are separated to obtain solid calcium carbonate and sodium hydroxide solution. S4. Calcium oxide recycling and aluminum-fluorine extraction: The calcium carbonate obtained in step S3 is calcined and decomposed to regenerate calcium oxide, which is then recycled back to step S3. At the same time, the sodium hydroxide solution obtained in step S3 is used to leach the leaching residue produced in step S1. An alkaline leaching reaction is carried out, and after the reaction, solid and liquid are separated to obtain sodium hydroxide leachate containing sodium aluminate and sodium fluoride and final tailings. S5. Aluminum-fluorine precipitation and closed-loop circulation of sodium carbonate: Carbon dioxide is introduced into the sodium hydroxide leaching solution obtained in step S4 to carry out carbonation and stepwise precipitation. First, the conditions are controlled to precipitate aluminum and fluorine in the form of cryolite. After filtration, cryolite product is obtained. The resulting filtrate is a crude sodium carbonate solution and is returned to step S1 as part of the preparation of sodium carbonate leaching solution to realize the closed-loop circulation of sodium carbonate.

2. The method for synergistic recovery and reagent recycling of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolyte according to claim 1, characterized in that, The liquid-to-solid ratio during sodium carbonate leaching in S1 is (3-10):1mL / g.

3. The method for synergistic recovery and reagent recycling of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolyte according to claim 1, characterized in that, The leaching time in S1 is 0.5-6 hours.

4. The method for synergistic recovery and reagent recycling of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolyte according to claim 1, characterized in that, The sodium carbonate solution concentration in S1 is 3.5-4.2 mol / L, and the leaching temperature is 180-220℃.

5. The method for synergistic recovery and reagent recycling of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolyte according to claim 1, characterized in that, The adsorbent used in the adsorption method described in S2 is a manganese-based or titanium-based lithium-ion sieve; the extraction system used in the solvent extraction method is a tributyl phosphate (TBP)-FeCl3 co-extraction system.

6. The method for synergistic recovery and reagent recycling of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolyte according to claim 1, characterized in that, The amount of calcium oxide added in the causticizing reaction in S3 is controlled according to the stoichiometric ratio of CaO:Na2CO3 as (1.0-1.2):

1.

7. The method for synergistic recovery and reagent recycling of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolyte according to claim 1, characterized in that, The causticizing reaction temperature in S3 is 60-95℃, and the reaction time is 0.5-2 hours.

8. The method for synergistic recovery and reagent recycling of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolyte according to claim 1, characterized in that, The calcination temperature of calcium carbonate in S4 is 800-1000℃, and the calcination time is 1-3 hours.

9. The method for synergistic recovery and reagent recycling of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolyte according to claim 1, characterized in that, When using sodium hydroxide solution to leach the residue in S4, the leaching temperature is 90-150℃ and the leaching time is 0.5-6 hours.

10. The method for synergistic recovery and reagent recycling of lithium, aluminum, sodium, and fluorine from lithium-containing waste aluminum electrolyte according to claim 1, characterized in that, In S5, the preferential precipitation of cryolite is achieved by controlling the rate of CO2 introduction and the final pH of the reaction; preferably, the final pH of the carbonization precipitation in S5 is controlled at 9-11.

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