Method for removing fluorine from battery leaching solution

Abstract

The present disclosure belongs to the field of wastewater treatment and resource recovery. Provided in the present disclosure is a method for removing fluorine from a battery leaching solution. In the method, a blank organic phase is first supplemented with iron to obtain a preliminary organic phase, and then the preliminary organic phase is mixed with the battery leaching solution for extraction to obtain a fluorine-loaded first organic phase and fluorine-removed raffinate. The present disclosure realizes the deep removal of low-content fluorine impurities while extracting and separating metals, and is particularly suitable for removing fluorine from a battery leaching solution with a low fluorine content, such that fewer impurities are generated during subsequent extraction and separation, the resulting metal product has a higher purity, and the cost of subsequent treatment of fluorine-containing wastewater can be greatly reduced.

Description

A method for removing fluorine from battery leachate Technical Field

[0001] The present invention belongs to the field of wastewater treatment and resource recovery, and relates to a method for removing fluorine from battery leachate. Background Art

[0002] With the rapid development of my country's new energy industry, lithium-ion batteries have gained widespread application due to their high energy storage, fast charge and discharge speeds, long cycle life, and environmental friendliness. With the large-scale application and development of lithium-ion batteries, more than 500,000 tons of lithium batteries are currently discarded worldwide each year. As demand for new energy continues to increase, the disposal and recycling of discarded lithium batteries has become a pressing issue.

[0003] The traditional recycling route for spent lithium-ion batteries is wet recycling, which involves discharging, disassembling, and crushing the batteries to obtain battery powder. The powder is then acid-leached to recover metals such as nickel, cobalt, manganese, and lithium. In existing technology, the battery leachate is directly extracted and backwashed with acid to produce a nickel-cobalt-manganese sulfate solution, which is then used to synthesize precursors. The raffinate is then pumped into a wastewater treatment tank for fluoride, heavy metal, and oil removal before being discharged after qualified treatment.

[0004] Since the electrolyte of used lithium batteries contains lithium hexafluorophosphate, and fluorine-containing compounds such as sodium fluoride are introduced during leaching and impurity removal, the nickel-cobalt-manganese solution after leaching and impurity removal of battery powder contains impurity fluorine. The traditional treatment and recovery route mentioned above is to first extract the valuable metal elements in the battery leachate into organic matter, leaving the fluorine in the extraction wastewater, then use calcium salt to precipitate the fluorine, and use a defluoridating agent to deeply remove the fluorine to a qualified level. There is a lack of effective methods for deep defluorination of the battery leachate. The above method does not defluorinate the battery leachate. When the fluorine concentration is high, a portion of fluorine will still enter the nickel-cobalt-manganese sulfate solution during extraction of the battery leachate, seriously affecting the quality of the metal products in the subsequent extraction and separation process.

[0005] Therefore, it is necessary to carry out deep defluorination treatment on battery leachate, especially further treatment of battery leachate with low fluorine content to completely eliminate the influence of fluorine element, which is of great significance for the subsequent process of metal resource recovery and the purity of recovered metals.

[0006] Summary of the Invention

[0007] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0008] In view of the problems existing in the prior art, the purpose of the present disclosure is to provide a method for defluoridating battery leachate, wherein the blank organic phase is first treated with iron and then used to extract the battery leachate; the present disclosure achieves the removal of low-content fluorine impurities while extracting and separating metals, and is particularly suitable for defluoridating battery leachate with low fluorine content, which can reduce the impurities generated in subsequent extraction and separation, and the resulting metal product has higher purity, and can greatly reduce the cost of subsequent treatment of fluorine-containing wastewater.

[0009] To achieve this goal, the present disclosure adopts the following technical solutions:

[0010] In a first aspect, the present disclosure provides a method for removing fluorine from a battery leachate, the method comprising:

[0011] The blank organic phase is treated with iron to obtain a prepared organic phase;

[0012] The prepared organic phase is mixed with the battery leachate and extracted to obtain a fluorine-loaded first organic phase and a fluorine-removed raffinate.

[0013] The method disclosed herein first treats a blank organic phase with iron to produce a preliminary organic phase. This preliminary organic phase is then mixed with a battery leachate and extracted to produce a fluorine-loaded first organic phase and a defluorinated raffinate. This method achieves the simultaneous removal of low-content fluorine impurities during metal extraction and separation. It is particularly suitable for defluoridating low-fluorine battery leachates, resulting in fewer impurities in subsequent extraction and separation, higher purity metal products, and significantly reduced costs for subsequent treatment of fluorine-containing wastewater.

[0014] The preparation method disclosed in the present invention requires that the blank organic phase be treated with iron before extraction. The iron-supplemented organic phase will cause the fluoride ions in the battery leachate to form iron ions in the organic phase with the iron ions to form iron fluoride complexes, which are then extracted into the organic phase.

[0015] The following are optional technical solutions of the present disclosure, but are not intended to limit the technical solutions provided by the present disclosure. Through the following technical solutions, the technical objectives and beneficial effects of the present disclosure can be better achieved and realized.

[0016] As an optional technical solution of the present disclosure, the blank organic phase includes an extractant, a co-extractant and a diluent.

[0017] In one embodiment, in the blank organic phase, the mass fraction of the extractant is 10% to 30%, for example, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28% or 30%, and the mass fraction of the co-extraction agent is 2% to 10%, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, and the balance is a diluent, but is not limited to the listed values. Other values ​​not listed within the above numerical range are also applicable.

[0018] In one embodiment, the extractant comprises a neutral phosphorus-based extractant.

[0019] In one embodiment, the neutral phosphorus extractant includes at least one of TBP, DEHEHP, Cyanex923, P350 or P311. Typical but non-limiting examples include a combination of TBP and DEHEHP, a combination of TBP and Cyanex923, a combination of TBP and P350, a combination of TBP and P311, a combination of DEHEHP and Cyanex923, a combination of P350 and DEHEHP, a combination of Cyanex923 and P350, a combination of P350 and P311, and the like.

[0020] In one embodiment, the co-extractant comprises an acidic extractant.

[0021] In one embodiment, the acidic extractant includes at least one of P204, P507, Cyanex272 or naphthenic acid, for example, typical but non-limiting examples include a combination of P204 and P507, a combination of P204 and Cyanex272, a combination of P204 and naphthenic acid, a combination of P507 and Cyanex272, a combination of P507 and naphthenic acid, or a combination of Cyanex272 and naphthenic acid.

[0022] In one embodiment, the diluent includes at least one of oil, kerosene, hexane, heptane or dodecane, such as a combination of kerosene and hexane, a combination of kerosene and heptane, a combination of kerosene and dodecane, a combination of hexane and heptane, a combination of hexane and dodecane, or a combination of heptane and dodecane, etc., and can be kerosene, and can further be sulfonated kerosene.

[0023] The present disclosure provides a new combined extractant formula as a blank organic phase, which is particularly suitable for treating low-content fluorine elements generated by waste ternary lithium battery leachate. It extracts low-fluorine impurities in the battery leachate to achieve the effect of separating fluorine from the leachate, thereby reducing the impact factors when separating nickel, cobalt, manganese and lithium, and increasing the product purity. An acidic extractant is used as a co-extractant to achieve iron supplementation, while a neutral phosphorus-type extractant is selected as an extractant and an acidic extractant is selected as a co-extractant to achieve the best fluorine extraction effect. Generally speaking, the higher the mass fraction of the extractant and co-extractant within a specified range, the better the fluorine extraction effect. That is, too low an extractant content will cause the fluorine extraction rate to decrease, but too high an extractant content will squeeze the ratio of the co-extractant and diluent, thereby increasing the organic viscosity and worsening the fluidity phase separation effect. Too low a co-extractant content will prevent the sufficient replenishment of iron ions, thereby affecting the extraction of fluoride ions. Too high a co-extractant content will also squeeze the space of the extractant and diluent, thereby increasing the organic viscosity and worsening the fluidity phase separation effect.

[0024] As an optional technical solution of the present disclosure, the method of iron supplementation treatment includes extraction using a ferric sulfate solution.

[0025] In one embodiment, the iron concentration in the ferric sulfate solution is 5 g / L to 20 g / L, for example, 5 g / L, 7 g / L, 9 g / L, 10 g / L, 12 g / L, 14 g / L, 16 g / L, 18 g / L or 20 g / L, but is not limited to the listed values. Other values ​​not listed within the above numerical range are also applicable.

[0026] The higher the concentration of the ferric sulfate solution used, the higher the efficiency of iron supplementation. However, when considering the cost in industrial production, a lower concentration should be appropriately selected within a limited range based on actual conditions.

[0027] In one embodiment, the iron supplementation method includes 2 to 4 stages of countercurrent extraction, the O / A ratio (volume ratio) is (1 to 20): 1, for example, 1: 1, 2: 1, 3: 1, 4: 1, 5: 1, 6: 1, 7: 1, 8: 1, 9: 1, 10: 1, 11: 1, 12: 1, 13: 1, 14: 1, 15: 1, 16: 1, 17: 1, 18: 1 or 19: 1, and the mixing time is 1 to 5 minutes, for example, 1 minute, 1.5 minutes, 2 minutes, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes or 5 minutes, but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0028] The O / A ratio (volume ratio) during iron supplementation is adjusted according to the iron concentration in the ferric sulfate solution. The lower the iron concentration, the higher the proportion of the aqueous phase should be to achieve the iron supplementation effect. When the blank organic phase is first treated with iron, the O / A ratio (volume ratio) can be selected to be (1-10):1, and further selected to be (1-3):1. When the organic phase is recovered for recycling, the O / A ratio of the iron supplementation treatment can be selected to be (10-20):1.

[0029] As an optional technical solution of the present disclosure, the battery leachate includes a ternary lithium-ion battery recovery leachate.

[0030] When the battery leachate includes a ternary lithium-ion battery recovery leachate, the fluorine-containing raffinate is a nickel-cobalt-manganese solution from which fluorine has been removed.

[0031] In one embodiment, the ternary lithium ion battery recovery leachate contains nickel, cobalt, manganese, lithium and fluorine, wherein the nickel content is 20g / L to 40g / L, for example, 20g / L, 22g / L, 24g / L, 26g / L, 28g / L, 30g / L, 32g / L, 34g / L, 36g / L, 38g / L or 40g / L, and the cobalt content is 5g / L to 15g / L, for example, 5g / L, 7g / L, 9g / L, etc. g / L, 11g / L, 13g / L or 15g / L, etc., the manganese content is 5g / L to 15g / L, such as 5g / L, 7g / L, 9g / L, 11g / L, 13g / L or 15g / L, etc., the lithium content is 100mg / L to 800mg / L, such as 100mg / L, 130mg / L, 150mg / L, 180mg / L, 200mg / L, 230mg / L, 250mg / L, 2 80mg / L, 300mg / L, 330mg / L, 350mg / L, 380mg / L, 400mg / L, 430mg / L, 450mg / L, 480mg / L, 500mg / L, 530mg / L, 550mg / L, 580mg / L, 600mg / L, 630mg / L, 650mg / L, 680mg / L, 700mg / L, 730mg / L, 75 0mg / L, 780mg / L or 800mg / L, etc., and the fluorine content is 80-300mg / L, for example, 80mg / L, 100mg / L, 130mg / L, 150mg / L, 180mg / L, 200mg / L, 230mg / L, 250mg / L, 280mg / L or 300mg / L, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0032] The preparation method disclosed herein is suitable for deep defluorination of battery leachates with low fluoride content. Therefore, ideal defluorination results can be achieved for leachates with fluoride content of 80 mg / L to 300 mg / L. If the fluoride content is too high, it may not be possible to completely remove the fluoride from the leachate.

[0033] As an optional technical solution disclosed in the present invention, the extraction includes 4 to 6 stages of countercurrent extraction, the O / A ratio (volume ratio) is (0.3 to 2):1, for example, 0.3:1, 0.5:1, 0.8:1, 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1 or 2:1, and the mixing time is 1 to 5 minutes, for example, 1 minute, 1.5 minutes, 2 minutes, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes or 5 minutes, but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0034] As an optional technical solution of the present disclosure, the method further includes mixing the first organic phase with a stripping agent and performing stripping to obtain a second organic phase and a fluorine-containing solution.

[0035] In one embodiment, the stripping agent includes a mixed solution of aluminum sulfate and sulfuric acid.

[0036] In one embodiment, the aluminum content in the stripping agent is 10 g / L to 20 g / L, for example, 10 g / L, 11 g / L, 12 g / L, 13 g / L, 14 g / L, 15 g / L, 16 g / L, 17 g / L, 18 g / L, 19 g / L or 20 g / L, etc. + The content is 10g / L to 30g / L, for example, 10g / L, 12g / L, 14g / L, 16g / L, 18g / L, 20g / L, 22g / L, 24g / L, 26g / L, 28g / L or 30g / L, but is not limited to the listed values. Other values ​​not listed within the above numerical range are also applicable.

[0037] The use of a mixed solution of aluminum sulfate and sulfuric acid can achieve the best effect of washing fluorine from the organic phase.

[0038] In one embodiment, the stripping includes 4 to 8 stages of countercurrent stripping, the O / A ratio (volume ratio) is (5-15):1, for example, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1 or 15:1, and the mixing time is 1-5 min, for example, 1 min, 1.5 min, 2 min, 2.5 min, 3 min, 3.5 min, 4 min, 4.5 min or 5 min, but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0039] As an optional technical solution of the present disclosure, the first organic phase is clarified before the stripping to obtain a clarified organic phase, which is then mixed with the stripping agent.

[0040] In one embodiment, the clarification comprises 1 to 3 stages of clarification, and the clarified aqueous phase is incorporated into the defluorinated raffinate.

[0041] The present disclosure clarifies the first organic phase first to prevent the organic phase from carrying other metal elements except fluorine in the battery leachate, thereby achieving the purpose of removing the entrained impurities.

[0042] As an optional technical solution of the present disclosure, the method further includes subjecting the second organic phase to an iron supplementation treatment to obtain a third organic phase and an iron supplemented raffinate, and the iron supplemented raffinate is reused for the iron supplementation treatment.

[0043] As an optional technical solution of the present disclosure, the method further comprises washing the third organic phase to obtain a washed organic phase, and the washed organic phase is reused for the extraction.

[0044] In one embodiment, the washing liquid comprises pure water, and the washing water is reused to prepare the ferric sulfate solution;

[0045] In one embodiment, the washing includes 2 to 4 stages of countercurrent washing, the O / A ratio (volume ratio) is (10-20):1, for example, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1 or 19:1, and the mixing time is 1 to 5 minutes, for example, 1 minute, 1.5 minutes, 2 minutes, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes or 5 minutes, but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0046] As an optional technical solution of the present disclosure, the method includes:

[0047] A blank organic phase with a total mass of 100% is prepared by combining 10% to 30% by mass of an extractant, 2% to 10% by mass of a co-extractant, and 60% to 82% by mass of a diluent; the extractant comprises a neutral phosphorus extractant, which comprises at least one of TBP, DEHEHP, Cyanex923, P350, or P311; the co-extractant comprises an acidic extractant, which comprises at least one of P204, P507, Cyanex272, or cyclohexane acid; and the diluent comprises at least one of oil, kerosene, hexane, heptane, or dodecane.

[0048] The waste ternary lithium-ion battery leachate with a nickel content of 20g / L-40g / L, a cobalt content of 5g / L-15g / L, a manganese content of 5g / L-15g / L, a lithium content of 100mg / L-800mg / L, and a fluorine content of 80mg / L-300mg / L is allowed to stand and used as a pre-extraction solution; a ferric sulfate solution with an iron concentration of 10g / L-20g / L is prepared; an aluminum content of 10g / L-20g / L, a H + A mixed solution of aluminum sulfate and sulfuric acid with a content of 10g / L to 30g / L is used as a stripping agent;

[0049] The blank organic phase was mixed with the ferric sulfate solution, and subjected to 2 to 4-stage countercurrent extraction, with the O / A ratio controlled at (10-20):1, the mixing time being 1-5 minutes, and iron supplementation treatment was performed to obtain a preliminary organic phase;

[0050] The prepared organic phase is mixed with the pre-extraction solution, and extracted using 4 to 6 stages of countercurrent extraction, with the O / A ratio controlled at (0.3 to 2):1, and the mixing time at 1 to 5 minutes, to obtain a fluorine-loaded first organic phase and a fluorine-free raffinate;

[0051] Clarifying the first organic phase using 1 to 3 stages of clarification to obtain a clarified organic phase and an aqueous phase, and incorporating the clarified aqueous phase into the defluorinated raffinate;

[0052] The clarified organic phase is mixed with a stripping agent, and stripping is performed using 4 to 8 levels of countercurrent stripping, with the O / A phase ratio controlled at (5 to 15):1 and the mixing time at 1 to 5 minutes to obtain a second organic phase and a fluorine-containing solution;

[0053] The second organic phase is mixed with the ferric sulfate solution, and 2 to 4 levels of countercurrent extraction are performed, the O / A phase ratio is controlled to be (10-20):1, the mixing time is 1-5 minutes, and iron supplementation treatment is performed to obtain a third organic phase and an iron-supplemented raffinate, and the iron-supplemented raffinate is used to prepare the ferric sulfate solution or is directly reused for iron supplementation treatment;

[0054] The third organic phase is washed with pure water for 2 to 4 levels of countercurrent washing, the O / A ratio is controlled to be (10-20):1, and the mixing time is 1-5 minutes to obtain a washed organic phase, which is reused in the extraction, and the obtained washing water is reused in the preparation of the ferric sulfate solution.

[0055] Compared with the existing technical solutions, the present disclosure has at least the following beneficial effects:

[0056] The method disclosed herein can achieve deep removal of fluorine from battery leachate, and is particularly suitable for further defluorination of low-fluorine-content battery leachate produced after the leaching and impurity removal process of waste ternary lithium-ion batteries. It can reduce impurities produced in the subsequent metal separation and recovery process, and increase product purity. At the same time, it can greatly reduce the cost of back-end wastewater treatment and the equipment conditions required for zero-discharge evaporation of back-end wastewater, and will not cause the fluorine content to concentrate and increase during evaporation, thereby corroding the equipment. The cost of long-term operation of the method is lower than the cost of defluorination using traditional defluorination agent precipitation method. The method can achieve a fluorine removal rate of more than 98% for low-fluorine impurities in waste ternary battery leachate, and the utilization rate of the main component of the stripping agent used can reach more than 99.5%.

[0057] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The accompanying drawings are used to provide a further understanding of the technical solution of this article and constitute a part of the specification. Together with the embodiments of this application, they are used to explain the technical solution of this article and do not constitute a limitation on the technical solution of this article.

[0059] FIG1 is a schematic flow chart of the method for removing fluorine from battery leachate in Example 1. DETAILED DESCRIPTION

[0060] The technical solution of the present disclosure is further illustrated below through specific implementation methods.

[0061] It should be apparent to those skilled in the art that the embodiments are only intended to help understand the present disclosure and should not be considered as specific limitations of the present disclosure.

[0062] Example 1

[0063] This embodiment provides a method for removing fluorine from battery leachate. The process diagram of the method is shown in FIG1 . The method comprises:

[0064] Step (1): Prepare a mixture of 15% TBP, 6% P204 and 79% kerosene as a blank organic phase; prepare a ferric sulfate solution with an iron concentration of 10 g / L; prepare an aluminum content of 15 g / L, H + A mixed solution of aluminum sulfate and sulfuric acid with a content of 12 g / L is used as a stripping agent;

[0065] Prepare waste ternary lithium-ion battery leachate A as the pre-extraction solution, which is the feed solution containing nickel, cobalt, manganese, lithium and fluorine after a series of treatments in the leaching process. The pH value of the feed solution is 5.0, and the composition is shown in Table 1;

[0066] Table 1

[0067] Step (2): mixing the blank organic phase with the ferric sulfate solution, adopting a two-stage countercurrent extraction, controlling the reaction phase O / A (volume ratio) of the blank organic phase and the ferric sulfate solution to be 1:1, the mixing time to be 30 minutes, the stirring rate to be 400 r / min, the standing time to be 10 minutes, controlling the temperature to be 25° C., performing iron supplementation treatment, and obtaining a preliminary organic phase and an aqueous phase after phase separation, and the aqueous phase can be used to prepare a new ferric sulfate solution;

[0068] Step (3): The prepared organic phase is mixed with the pre-extraction liquid, and a multi-stage countercurrent fractional distillation extraction is performed, the extraction stage is controlled to be 4, the O / A (volume ratio) of the prepared organic phase and the pre-extraction liquid is 1:1, the mixing time is 3 minutes, and extraction is performed. After phase separation, a first organic phase loaded with fluorine and a defluorinated raffinate (i.e., a raffinate) are obtained, and the defluorinated raffinate is retained for subsequent separation of nickel, cobalt, manganese, and lithium;

[0069] Step (4): clarifying the first organic phase using a two-stage clarification chamber for 20 minutes to obtain a clarified organic phase and an aqueous phase, and incorporating the clarified aqueous phase into the defluorinated raffinate;

[0070] Step (5): mixing the clarified organic phase with a stripping agent, controlling the number of stripping stages to 6, the O / A (volume ratio) of the clarified organic phase to the stripping agent to be 15:1, the mixing time to be 3 min, and performing stripping to obtain a second organic phase and a fluorine-containing solution (i.e., stripping solution) after phase separation;

[0071] Step (6): mixing the second organic phase with the ferric sulfate solution, adopting a two-stage countercurrent extraction, controlling the reaction phase O / A (volume ratio) of the second organic phase to the ferric sulfate solution to be 15:1, the mixing time to be 30 min, the stirring rate to be 400 r / min, the standing time to be 10 min, controlling the temperature to be 25° C., performing iron supplementation treatment, and obtaining a third organic phase and an iron-supplemented raffinate after phase separation, and the iron-supplemented raffinate is directly reused in the iron supplementation treatment as the ferric sulfate solution;

[0072] Step (7): washing the third organic phase, with the washing stage being 2, the detergent being pure water, controlling the reaction ratio O / A (volume ratio) of the third organic phase to the detergent to be 10:1, the mixing time being 3 min, washing the organic phase, and the washed organic phase being returned to the extraction, and the obtained washing water being returned to the preparation of the ferric sulfate solution.

[0073] Example 2

[0074] This embodiment provides a method for removing fluorine from battery leachate. The process diagram of the method is shown in FIG1 . The method comprises:

[0075] Step (1): Prepare a mixture of 15% TBP, 6% P204 and 79% kerosene as a blank organic phase; prepare a ferric sulfate solution with an iron concentration of 10 g / L; prepare an aluminum content of 15 g / L, H + A mixed solution of aluminum sulfate and sulfuric acid with a content of 12 g / L is used as a stripping agent;

[0076] Prepare waste ternary lithium-ion battery leachate B as the pre-extraction solution, which is the feed solution containing nickel, cobalt, manganese, lithium and fluorine after a series of treatments in the leaching process. The pH value of the feed solution is 6.5, and the composition is shown in Table 2;

[0077] Table 2

[0078] Step (2): mixing the blank organic phase with the ferric sulfate solution, adopting a two-stage countercurrent extraction, controlling the reaction phase O / A (volume ratio) of the blank organic phase and the ferric sulfate solution to be 1:1, the mixing time to be 30 minutes, the stirring rate to be 400 r / min, the standing time to be 10 minutes, controlling the temperature to be 25° C., performing iron supplementation treatment, and obtaining a preliminary organic phase and an aqueous phase after phase separation, and the aqueous phase can be used to prepare a new ferric sulfate solution;

[0079] Step (3): The prepared organic phase is mixed with the pre-extraction liquid, and a multi-stage countercurrent fractional distillation extraction is performed, the extraction stage is controlled to be 3, the O / A (volume ratio) of the prepared organic phase to the pre-extraction liquid is 1:2, the mixing time is 5 minutes, and extraction is performed. After phase separation, a first organic phase loaded with fluorine and a defluorinated raffinate (i.e., a raffinate) are obtained, and the defluorinated raffinate is retained for subsequent separation of nickel, cobalt, manganese, and lithium;

[0080] Step (4): clarifying the first organic phase using a two-stage clarification chamber for 10 minutes to obtain a clarified organic phase and an aqueous phase, and incorporating the clarified aqueous phase into the defluorinated raffinate;

[0081] Step (5): mixing the clarified organic phase with a stripping agent, controlling the stripping stage number to 5, the reaction phase O / A (volume ratio) of the clarified organic phase to the stripping agent to be 10:1, the mixing time to be 5 min, performing stripping, and obtaining a second organic phase and a fluorine-containing solution (i.e., stripping solution) after phase separation;

[0082] Step (6): mixing the second organic phase with the ferric sulfate solution, adopting a two-stage countercurrent extraction, controlling the reaction phase O / A (volume ratio) of the second organic phase and the ferric sulfate solution to be 10:1, the mixing time to be 30 min, the stirring rate to be 400 r / min, the standing time to be 10 min, controlling the temperature to be 25° C., performing iron supplementation treatment, and obtaining a third organic phase and an iron-supplemented raffinate after phase separation, and the iron-supplemented raffinate is directly reused in the iron supplementation treatment as the ferric sulfate solution;

[0083] Step (7): washing the third organic phase, the washing stage is 1, the detergent is pure water, the reaction ratio O / A (volume ratio) of the third organic phase to the detergent is controlled to be 10:1, the mixing time is 5 minutes, and the organic phase is washed. The washed organic phase is returned to the extraction, and the obtained washing water is returned to prepare the ferric sulfate solution.

[0084] Example 3

[0085] This embodiment provides a method for removing fluorine from a battery leachate. In the method, the mass fraction of TBP is adjusted from 15% to 7%, the mass fraction of P204 is kept unchanged, and the mass fraction of kerosene is adjusted from 79% to 87%. Except for the above, other conditions are exactly the same as those in Example 1.

[0086] Example 4

[0087] This embodiment provides a method for removing fluorine from a battery leachate. In the method, the mass fraction of TBP is adjusted from 15% to 10%, the mass fraction of P204 is kept unchanged, and the mass fraction of kerosene is adjusted from 79% to 84%. Except for the above, other conditions are exactly the same as those in Example 1.

[0088] Example 5

[0089] This embodiment provides a method for removing fluorine from a battery leachate. In the method, the mass fraction of TBP is adjusted from 15% to 30%, the mass fraction of P204 is kept unchanged, and the mass fraction of kerosene is adjusted from 79% to 64%. Except for the above, other conditions are exactly the same as those in Example 1.

[0090] Example 6

[0091] This embodiment provides a method for removing fluorine from a battery leachate. In the method, the mass fraction of TBP is adjusted from 15% to 33%, the mass fraction of P204 is kept unchanged, and the mass fraction of kerosene is adjusted from 79% to 61%. Except for the above, other conditions are exactly the same as those in Example 1.

[0092] Example 7

[0093] This embodiment provides a method for removing fluorine from a battery leachate. In the method, the mass fraction of P204 is adjusted from 6% to 1%, the mass fraction of TBP is kept unchanged, and the mass fraction of kerosene is adjusted from 79% to 84%. Except for the above, other conditions are exactly the same as those in Example 1.

[0094] Example 8

[0095] This embodiment provides a method for removing fluorine from a battery leachate. In the method, the mass fraction of P204 is adjusted from 6% to 2%, the mass fraction of TBP is kept unchanged, and the mass fraction of kerosene is adjusted from 79% to 83%. Except for the above, other conditions are exactly the same as those in Example 1.

[0096] Example 9

[0097] This embodiment provides a method for removing fluorine from a battery leachate. In the method, the mass fraction of P204 is adjusted from 6% to 10%, the mass fraction of TBP is kept unchanged, and the mass fraction of kerosene is adjusted from 79% to 75%. Except for the above, other conditions are exactly the same as those in Example 1.

[0098] Example 10

[0099] This embodiment provides a method for removing fluorine from a battery leachate. In the method, the mass fraction of P204 is adjusted from 6% to 12%, the mass fraction of TBP is kept unchanged, and the mass fraction of kerosene is adjusted from 79% to 73%. Except for the above, other conditions are exactly the same as those in Example 1.

[0100] Example 11

[0101] This embodiment provides a method for removing fluoride from battery leachate. In the method, the concentration of iron in the ferric sulfate solution is adjusted from 10 g / L to 2 g / L. Except for the above, other conditions are exactly the same as those in Example 1.

[0102] Example 12

[0103] This embodiment provides a method for removing fluoride from battery leachate. In the method, the concentration of iron in the ferric sulfate solution is adjusted from 10 g / L to 5 g / L. Except for the above, other conditions are exactly the same as those in Example 1.

[0104] Example 13

[0105] This embodiment provides a method for removing fluoride from battery leachate. In the method, the concentration of iron in the ferric sulfate solution is adjusted from 10 g / L to 20 g / L. Except for the above, other conditions are exactly the same as those in Example 1.

[0106] Example 14

[0107] This embodiment provides a method for removing fluoride from battery leachate. In the method, the concentration of iron in the ferric sulfate solution is adjusted from 10 g / L to 23 g / L. Except for the above, other conditions are exactly the same as those in Example 1.

[0108] Comparative Example 1

[0109] This comparative example provides a method for removing fluorine from a battery leachate. The method does not perform iron supplementation on the blank organic phase, but directly mixes the blank organic phase with the pre-extraction solution for extraction. Except for the above, other conditions are exactly the same as those in Example 1.

[0110] In the embodiment and comparative example, the raffinate obtained by extracting the pre-extraction liquid in step (3) was tested, and the fluorine-containing solution after stripping with the stripping agent in step (5) was tested. Fluoride ions were detected using a fluoride ion selective electrode method using the detection method of GB7484-87. The results are recorded in Table 3.

[0111] Table 3

[0112] It can be seen from Table 1 and Table 3 that: 1. Since the principle of fluorine extraction relies on complex extraction with the iron ion element in the organic solution, fluorine cannot be extracted without iron supplementation in the blank organic solution; 2. It is particularly important to select a suitable extractant formula and a suitable iron supplement solution according to cost requirements in actual production.

Claims

1. A method for removing fluorine from battery leachate, comprising: Performing iron supplementation treatment on a blank organic phase to obtain a preliminary organic phase; Mixing the preliminary organic phase with the battery leachate and performing extraction to obtain a first organic phase loaded with fluorine and a defluorinated raffinate.

2. The method according to claim 1, wherein, The blank organic phase includes an extractant, a synergistic extractant, and a diluent.

3. The method according to claim 2, wherein, In the blank organic phase, the mass fraction of the extractant is 10% - 30%, the mass fraction of the synergistic extractant is 2% - 10%, and the balance is the diluent.

4. The method according to claim 2 or 3, wherein, The extractant includes a neutral phosphorus extractant.

5. The method according to any one of claims 2-4, wherein, The synergistic extractant includes an acidic extractant.

6. The method according to any one of claims 1-5, wherein, The method for iron supplementation treatment includes performing extraction using a ferric sulfate solution.

7. The method according to claim 6, wherein, The iron concentration in the ferric sulfate solution is 5 g / L - 20 g / L.

8. The method according to claim 6 or 7, wherein, The method for iron supplementation treatment includes 2 to 4 stages of countercurrent extraction, with an O / A ratio of (1 - 20):

1.

9. The method according to any one of claims 1-8, wherein The battery leachate includes a ternary lithium-ion battery recycling leachate.

10. The method according to any one of claims 1-9, wherein, The content of fluorine element in the ternary lithium-ion battery recycling leachate is 80 mg / L - 300 mg / L.

11. According to the method of any one of claims 1-10, wherein, The extraction includes 4 to 6 stages of countercurrent extraction, with an O / A ratio of (0.3 - 2):1 and a mixing time of 1 - 5 min.

12. The method according to any one of claims 1-11, wherein, The method further includes mixing the first organic phase with an anti-extraction agent and performing anti-extraction to obtain a second organic phase and a fluorine-containing solution; Optionally, the anti-extraction agent includes a mixed solution composed of aluminum sulfate and sulfuric acid.

13. The method according to claim 12, wherein, Before the first organic phase undergoes the anti-extraction, it is first clarified to obtain a clarified organic phase, and then mixed with the anti-extraction agent; Optionally, the aqueous phase obtained by clarification is incorporated into the defluorinated raffinate.

14. The method according to claim 12 or 13, wherein, The method further includes performing iron supplementation treatment on the second organic phase to obtain a third organic phase and an iron-supplemented raffinate, and the iron-supplemented raffinate is recycled for the iron supplementation treatment.

15. The method according to claim 14, wherein The method further includes washing the third organic phase to obtain a washed organic phase, and the washed organic phase is recycled for the extraction.

16. The method according to any one of claims 1-15, wherein, The method includes: Taking an extractant with a mass fraction of 10% - 30%, a synergistic extractant with a mass fraction of 2% - 10%, and a diluent with a mass fraction of 60% - 82%, and formulating a blank organic phase with a total mass of 100%; the extractant includes a neutral phosphorus extractant, and the neutral phosphorus extractant includes at least one of TBP, DEHEHP, Cyanex923, P350, or P311; the synergistic extractant includes an acidic extractant, and the acidic extractant includes at least one of P204, P507, Cyanex272, or naphthenic acid; the diluent includes at least one of oil, kerosene, hexane, heptane, or dodecane; After standing still the leaching solution of waste ternary lithium-ion battery with nickel content of 20 g / L to 40 g / L, cobalt content of 5 g / L to 15 g / L, manganese content of 5 g / L to 15 g / L, lithium content of 100 mg / L to 800 mg / L, and fluorine content of 80 mg / L to 300 mg / L, it is used as the pre-extraction solution; prepare a ferric sulfate solution with iron concentration of 10 g / L to 20 g / L; prepare aluminum sulfate with aluminum content of 10 g / L to 20 g / L and H + content of 10 g / L to 30 g / L and sulfur A mixed solution of acid as the anti-extraction agent; Mixing the blank organic phase with the ferric sulfate solution, and performing iron supplementation treatment by 2 to 4 stages of countercurrent extraction, controlling the O / A ratio to be (10 - 20):1 and the mixing time to be 1 - 5 min to obtain a preliminary organic phase; Mixing the preliminary organic phase with the pre-extraction liquid, and performing extraction by 4 to 6 stages of countercurrent extraction, controlling the O / A ratio to be (0.3 - 2):1 and the mixing time to be 1 - 5 min to obtain a first organic phase loaded with fluorine and a defluorinated raffinate; The first organic phase is clarified through 1 to 3 stages of clarification to obtain a clarified organic phase and an aqueous phase. The obtained aqueous phase from the clarification is incorporated into the defluorinated raffinate. The clarified organic phase is mixed with a stripping agent and subjected to 4 to 8 stages of countercurrent stripping. The O / A ratio is controlled to be (5 - 15):1, and the mixing time is 1 to 5 minutes for stripping to obtain a second organic phase and a fluorine-containing solution. The second organic phase is mixed with a ferric sulfate solution and subjected to 2 to 4 stages of countercurrent extraction. The O / A ratio is controlled to be (10 - 20):1, and the mixing time is 1 to 5 minutes for iron supplementation treatment to obtain a third organic phase and an iron-supplemented raffinate. The iron-supplemented raffinate is used to prepare the ferric sulfate solution or directly recycled for iron supplementation treatment. The third organic phase is washed through 2 to 4 stages of countercurrent washing with pure water. The O / A ratio is controlled to be (10 - 20):1, and the mixing time is 1 to 5 minutes to obtain a washed organic phase. The washed organic phase is recycled for the extraction, and the obtained washing water is recycled for preparing the ferric sulfate solution.

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