A method for defluorination during the recycling of ternary lithium waste

Abstract

This invention relates to a method for defluorinating ternary lithium-ion waste during recycling. The method includes the following steps: reducing and roasting ternary black powder to obtain lithium extraction slag; reducing and acid leaching the lithium extraction slag to obtain a leachate; neutralizing and removing impurities from the leachate to obtain a neutralized filtrate and a neutralized residue; extracting and removing impurities from the neutralized filtrate to obtain a purified solution with a fluoride content of less than 500 mg / L; extracting the purified solution with a mixed fluoride extractant to obtain a loaded organic phase and a raffinate; and regenerating and recycling the loaded organic phase. The defluorinating method for ternary lithium-ion waste recycling provided by this invention can prepare high-purity nickel-cobalt-manganese-lithium salts, and is simple to operate, has high defluorinating efficiency, and allows for the recycling of the extractant.

Description

Technical Field

[0001] This invention belongs to the field of waste battery recycling technology, and relates to a method for defluorination during the recycling of ternary lithium batteries. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the recycling and disposal of waste lithium-ion batteries has become an important issue for resource recycling and environmental protection. Ternary lithium-ion batteries are widely used due to their high energy density and good cycle performance, but their recycling process faces many technical challenges, especially in the preparation of high-purity nickel-cobalt-manganese lithium salts. Ternary waste (black powder) is rich in valuable metals such as nickel, cobalt, manganese, and lithium, and is usually recycled using hydrometallurgical processes. However, the fluorine in the waste mainly comes from the electrolyte (such as LiPF6) and binders. During acid leaching, fluoride ions enter the leachate, severely affecting subsequent extraction and separation and product purity. Fluoride ions form stable complexes with metal ions, reducing extraction efficiency, corroding equipment, and the final products (such as battery-grade nickel sulfate and cobalt sulfate) have strict requirements for fluoride content (usually below 10 mg / L).

[0003] Currently, the mainstream technical route for ternary lithium black powder recovery typically includes multiple steps such as pretreatment, leaching, impurity removal, and extraction separation. Existing aqueous solution defluorination technologies mainly include chemical precipitation, adsorption, and solvent extraction. CN119040634A discloses a method for defluorination, heavy metal removal, and lithium extraction from high-fluoride battery black powder leachate. This method utilizes the high aluminum content in the battery black powder leachate for precipitation defluorination, achieving a defluorination effect comparable to adding aluminum-based defluorinating agents. Further deep defluorination is then achieved using defluorination resin. However, resin adsorption suffers from problems such as small processing capacity, frequent regeneration, and difficulty in treating regeneration waste liquid, resulting in high industrial operating costs. CN120666178A proposes a method for impurity removal from ternary lithium black powder leachate. This method involves adjusting the pH with calcium reagents for primary impurity removal, followed by secondary impurity removal by mixing with fluorides, and finally achieving defluorination through acidification and TBP extraction. However, the defluorination depth using TBP alone after solution acidification is insufficient, with residual fluoride reaching 300 mg / L. Subsequent treatment of the acidified solution requires alkali addition for reversion, increasing auxiliary material costs. CN117867277A discloses a defluorination extractant and a method for deep defluorination from acidic sulfate solutions. The extractant contains cation exchange groups and neutral molecular complexing groups. The extractant is subjected to countercurrent extraction with a fluorinated sulfate solution. The fluorine-loaded organic phase is back-extracted with an acid solution containing complex fluoride metal ions. This can reduce the fluoride in the solution to 1ppm~15ppm. However, the bifunctional extractant has a complex structure and high synthesis cost. Moreover, the single extraction process has a large load and rapid extractant loss when treating high-fluoride solutions. The complex fluoride metal ions introduced during the back-extraction process may cause secondary pollution.

[0004] Therefore, there is a need for a method for defluorinating ternary waste during recycling that is simple to operate, has high defluorination efficiency, and allows for the recycling of the extractant. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for defluorination during the recycling of ternary waste materials. This method can solve the technical problems of long recycling processes for ternary black powder, incomplete fluoride removal by traditional defluorination methods, and difficulty in preparing high-purity nickel-cobalt-manganese-lithium salts. It can achieve the goals of simple operation, high defluorination efficiency, and recyclable extractant.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] This invention provides a method for defluorination during the recycling of ternary lithium-ion waste, the method comprising the following steps:

[0008] S1. Ternary black powder is subjected to reduction roasting to obtain lithium extraction residue; the lithium extraction residue is subjected to reduction acid leaching to obtain leachate;

[0009] S2. The leachate is neutralized and impurities are removed to obtain a neutralized filtrate and a neutralized residue; the neutralized filtrate is extracted and impurities are removed to obtain a purified solution with a fluorine content of less than 500 mg / L.

[0010] S3. The mixed fluorine extractant is extracted with the impurity removal solution to obtain a loaded organic phase and raffinate;

[0011] The supported organic phase is regenerated and recycled.

[0012] This invention addresses the defluorination requirements in the recycling of ternary lithium waste by employing a two-stage process combining neutralization precipitation for coarse defluorination and extraction for deep defluorination. First, ternary black powder is reduced and roasted to obtain lithium extraction slag. This slag is then subjected to reducing acid leaching to obtain a fluorinated leachate. The leachate is then subjected to neutralization and extraction for further impurity removal. During this process, the complexation and precipitation of iron and aluminum ions inherent in the leachate raw material, along with the chemical precipitation introduced by the neutralization step, achieves efficient preliminary removal of fluoride without the need for additional specialized defluorinating agents. This reduces the fluoride content in the leachate from several g / L to below 500 mg / L, yielding a purified solution. Subsequently, a fluorine extractant is mixed with the purified solution for deep defluorination, resulting in a loaded organic phase and a raffinate with a fluoride content reduced to below 10 mg / L. Simultaneously, the loaded organic phase is regenerated and recycled back to the extraction process, forming a stable closed-loop regeneration and recycling system for the extractant.

[0013] In some embodiments, the reducing agent used in the reducing acid leaching includes any one or a combination of at least two of hydrogen peroxide, sodium sulfite, or sodium metabisulfite.

[0014] In some embodiments, the acid used in the reducing acid leaching includes sulfuric acid.

[0015] In some embodiments, the content of F in the leachate is 2 g / L to 10 g / L.

[0016] In some embodiments, the neutralizing agent used for neutralization and impurity removal includes any one or a combination of at least two of liquid alkali, lime milk, sodium carbonate, or calcium hydroxide.

[0017] In some embodiments, the pH value for neutralization and impurity removal is 4 to 6.

[0018] In some embodiments, the neutralization and impurity removal temperature is 40°C to 90°C.

[0019] In some embodiments, the neutralization and impurity removal time is 3h to 6h.

[0020] In some embodiments, the extractant used for the extraction and impurity removal includes P204.

[0021] In some embodiments, the O / A ratio of the extraction is 0.5:1 to 5:1.

[0022] In some embodiments, the extraction stages are 2 to 5.

[0023] In some embodiments, the contact time for a single extraction is 5 to 10 minutes, and the phase separation time is 5 to 30 minutes.

[0024] In some embodiments, the regeneration cycle includes: acid washing of the loaded organic phase to obtain an acid washing solution; back-extraction of the acid washing solution using an inorganic aluminum salt solution, followed by iron soap treatment of the obtained organic phase to obtain an iron soap organic phase; and washing of the iron soap organic phase with water to achieve the regeneration cycle of the loaded organic phase.

[0025] In some embodiments, the pickling is carried out using sulfuric acid with a concentration of 0.01 mol / L to 0.5 mol / L, the pickling O / A ratio is 10:1 to 30:1, and the number of pickling stages is 1 to 5.

[0026] In some embodiments, the inorganic aluminum salt solution is an aluminum sulfate solution with an aluminum ion concentration of 3 g / L to 15 g / L;

[0027] In some embodiments, the O / A ratio of the back-extraction is 10:1 to 20:1, the contact time is 5 min to 10 min, and the number of stages is 2 to 4.

[0028] In some embodiments, the iron soap agent used in the iron soap treatment is a ferric sulfate solution with an iron ion concentration of 1 g / L to 10 g / L.

[0029] In some embodiments, the O / A ratio of the iron soap treatment is 10:1 to 20:1, the contact time is 5 min to 10 min, and the number of stages is 1 to 3.

[0030] In some embodiments, the O / A ratio of the water wash is 10:1 to 40:1, and the number of stages is 1 to 3.

[0031] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The method for defluorination in the recycling of ternary waste provided by this invention adopts a two-stage process combining neutralization precipitation for coarse defluorination and extraction for deep defluorination. First, ternary black powder is reduced and roasted to obtain lithium extraction slag. The lithium extraction slag is then reduced and acid-leached to obtain a fluorine-containing leachate. The leachate is then subjected to neutralization and extraction for impurity removal in sequence. During the process, the complexation and precipitation of iron and aluminum ions naturally present in the leachate raw material, as well as the chemical precipitation introduced by the neutralization process, are utilized to achieve efficient preliminary removal of fluoride without the need for additional special defluorinating agents. The fluoride content in the leachate, which is in the range of several g / L, is reduced to below 500 mg / L to obtain an impurity-removed solution. Subsequently, a fluorine extractant is mixed with the impurity-removed solution for deep defluorination, resulting in a loaded organic phase and a raffinate with a fluoride content reduced to below 10 mg / L. At the same time, the loaded organic phase can be recycled and returned to the extraction process for reuse, forming a stable closed-loop regeneration and recycling system for the extractant. Attached Figure Description

[0034] Figure 1 A process flow diagram is provided for the method of this invention. Detailed Implementation

[0035] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0036] One embodiment of the present invention provides a method for defluorination during the recycling of ternary lithium waste, the process flow diagram of which is shown below. Figure 1 As shown, the method includes the following steps:

[0037] S1. Ternary black powder is reduced and roasted to obtain lithium extraction slag (mainly nickel, cobalt, and manganese high-valence oxides); the lithium extraction slag is reduced and acid-leached to obtain leachate (containing nickel, cobalt, and manganese main metals and impurities such as iron, aluminum, silicon, phosphorus, and fluorine).

[0038] S2. The leachate is neutralized and impurities are removed to obtain a neutralized filtrate and a neutralized residue; the neutralized filtrate is extracted and impurities are removed to obtain a purified solution with a fluorine content of less than 500 mg / L.

[0039] S3. The mixed fluorine extractant is extracted with the impurity removal solution to obtain a loaded organic phase and raffinate;

[0040] The supported organic phase is regenerated and recycled.

[0041] This invention addresses the defluorination requirements in the recycling of ternary lithium waste by employing a two-stage process combining neutralization precipitation for coarse defluorination and extraction for deep defluorination. First, ternary black powder is reduced and roasted to obtain lithium extraction slag. This slag is then subjected to reducing acid leaching to obtain a fluorinated leachate. The leachate is then subjected to neutralization and extraction for further impurity removal. During this process, the complexation and precipitation of iron and aluminum ions inherent in the leachate raw material, along with the chemical precipitation introduced by the neutralization step, achieves efficient preliminary removal of fluoride without the need for additional specialized defluorinating agents. This reduces the fluoride content in the leachate from several g / L to below 500 mg / L, yielding a purified solution. Subsequently, a fluorine extractant is mixed with the purified solution for deep defluorination, resulting in a loaded organic phase and a raffinate with a fluoride content reduced to below 10 mg / L. Simultaneously, the loaded organic phase is regenerated and recycled back to the extraction process, forming a stable closed-loop regeneration and recycling system for the extractant.

[0042] In some embodiments, the reducing agent used in the reducing acid leaching includes any one or a combination of at least two of hydrogen peroxide, sodium sulfite, or sodium metabisulfite. Typical but non-limiting combinations include a combination of hydrogen peroxide and sodium sulfite, a combination of hydrogen peroxide and sodium metabisulfite, a combination of sodium sulfite and sodium metabisulfite, or a combination of hydrogen peroxide, sodium sulfite, and sodium metabisulfite.

[0043] In some embodiments, the amount of reducing agent used in the reducing acid leaching is 1.05 to 1.2 times the theoretical amount, for example, it can be 1.05 times, 1.08 times, 1.1 times, 1.12 times, 1.15 times, 1.18 times or 1.2 times, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0044] In some embodiments, the acid used in the reducing acid leaching includes sulfuric acid.

[0045] In some embodiments, the amount of sulfuric acid used in the reducing acid leaching is 1.05 to 1.2 times the theoretical amount, for example, it can be 1.05 times, 1.08 times, 1.1 times, 1.12 times, 1.15 times, 1.18 times or 1.2 times, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0046] In some embodiments, the liquid-to-solid ratio of the reducing acid leaching can be 4:1 to 8:1 (e.g., 4:1, 5:1, 6:1, 7:1, or 8:1, etc.), and the unit of the liquid-to-solid ratio is mL / g; the reducing acid leaching temperature is 60℃ to 90℃ (e.g., 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, or 90℃, etc.), and the time is 3h to 6h (e.g., 3h, 4h, 5h, or 6h, etc.).

[0047] In some embodiments, the content of F in the leachate is 2 g / L to 10 g / L, for example, it can be 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L or 10 g / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0048] In some embodiments, the neutralizing agent used for neutralization and impurity removal includes any one or a combination of at least two of liquid alkali, lime milk, sodium carbonate, or calcium hydroxide.

[0049] In some embodiments, the pH value for neutralization and impurity removal is 4 to 6, for example, it can be 4, 4.5, 5, 5.5 or 6, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0050] In some embodiments, the neutralization and impurity removal temperature is 40°C to 90°C, for example, it can be 40°C, 50°C, 60°C, 70°C, 80°C or 90°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0051] In some embodiments, the neutralization and impurity removal time is 3h to 6h, for example, it can be 3h, 4h, 5h or 6h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0052] In some embodiments, the extractant used for the extraction and impurity removal includes P204.

[0053] In some embodiments, the P204 in the extractant is diluted with sulfonated kerosene, and the volume fraction of P204 is 20% to 30% (e.g., it can be 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30%, etc.).

[0054] In some embodiments, the O / A ratio for extraction and impurity removal is 0.5:1 to 1.5:1, for example, it can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1 or 1.5:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0055] In some embodiments, the extraction and impurity removal stages are 6 to 10 (e.g., 6, 7, 8, 9 or 10 stages), the single-stage extraction contact time is 3 min to 6 min (e.g., 3 min, 4 min, 5 min or 6 min, etc.), and the phase separation time is 5 min to 20 min (e.g., 5 min, 8 min, 10 min, 12 min, 15 min, 16 min, 18 min or 20 min, etc.).

[0056] In some embodiments, the O / A ratio of the extraction is 0.5:1 to 5:1, for example, it can be 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1 or 5:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0057] In some embodiments, the extraction stages are 2 to 5.

[0058] In some embodiments, the contact time for a single extraction is 5 to 10 minutes, and the phase separation time is 5 to 30 minutes.

[0059] In some embodiments, the regeneration cycle includes: acid washing of the loaded organic phase to obtain an acid washing solution; back-extraction of the acid washing solution using an inorganic aluminum salt solution, followed by iron soap treatment of the obtained organic phase to obtain an iron soap organic phase; and washing of the iron soap organic phase with water to achieve the regeneration cycle of the loaded organic phase.

[0060] In some embodiments, the pickling is performed using sulfuric acid with a concentration of 0.01 mol / L to 0.5 mol / L (e.g., 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, or 0.5 mol / L, etc.), the pickling O / A ratio is 10:1 to 30:1 (e.g., 10:1, 15:1, 20:1, 25:1, or 30:1, etc.), and the number of stages is 1 to 5 (e.g., stage 1, stage 2, stage 3, stage 4, or stage 5).

[0061] In some embodiments, the inorganic aluminum salt solution is an aluminum sulfate solution with an aluminum ion concentration of 3 g / L to 15 g / L (e.g., 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L, 11 g / L, 12 g / L, 13 g / L, 14 g / L, or 15 g / L, etc.).

[0062] In some embodiments, the O / A ratio of the back-extraction is 10:1 to 20:1 (e.g., 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1, etc.), the contact time is 5 min to 10 min (e.g., 5 min, 6 min, 7 min, 8 min, 9 min, or 10 min, etc.), and the number of stages is 2 to 4 (e.g., 2, 3, or 4 stages).

[0063] In some embodiments, the iron soap agent used in the iron soap treatment is a ferric sulfate solution with an iron ion concentration of 1 g / L to 10 g / L, for example, it can be 1 g / L, 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L or 10 g / L, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0064] In some embodiments, the O / A ratio of the iron soap treatment is 10:1 to 20:1 (e.g., 10:1, 12:1, 15:1, 16:1, 18:1, or 20:1, etc.), the contact time is 5 min to 10 min (e.g., 5 min, 6 min, 7 min, 8 min, 9 min, or 10 min, etc.), and the number of stages is 1 to 3 (e.g., 1 stage, 2 stage, or 3 stage).

[0065] In some embodiments, the O / A ratio of the water wash is 10:1 to 40:1 (e.g., it can be 10:1, 15:1, 20:1, 25:1, 30:1, 35:1 or 40:1, etc.), and the number of stages is 1 to 3 (e.g., it can be 1 stage, 2 stages or 3 stages).

[0066] As a preferred embodiment of the method provided by the present invention, the method includes the following steps:

[0067] (1) The ternary black powder is reduced and roasted to obtain lithium extraction slag (mainly nickel, cobalt and manganese high-valence oxides); the lithium extraction slag is reduced and acid leached to obtain leachate (containing nickel, cobalt and manganese main metals and impurities such as iron, aluminum, silicon, phosphorus and fluorine).

[0068] The reduction calcination temperature is 600℃~700℃, the mass of the carbonaceous reducing agent is 10%~15% of the ternary black powder, and the reduction calcination time is 60min~120min;

[0069] The reducing agent used in the reducing acid leaching includes any one or a combination of at least two of hydrogen peroxide, sodium sulfite, or sodium metabisulfite; the amount of reducing agent used is 1.05 to 1.2 times the theoretical amount.

[0070] The acid used in the reducing acid leaching includes sulfuric acid; the amount of sulfuric acid used is 1.05 to 1.2 times the theoretical amount.

[0071] The liquid-to-solid ratio of the reducing acid leaching can be 4:1 to 8:1, the temperature can be 60℃ to 90℃, and the time can be 3h to 6h.

[0072] The content of F in the leachate is 2g / L~10g / L;

[0073] (2) The leachate is neutralized and impurities are removed to obtain a neutralized filtrate and a neutralized residue; the neutralized filtrate is extracted and impurities are removed to obtain a purified solution with a fluorine content of less than 500 mg / L;

[0074] The neutralizing agent used for neutralization and impurity removal includes any one or a combination of at least two of liquid alkali, lime milk, sodium carbonate, or calcium hydroxide; the pH value of the neutralization and impurity removal is 4~6, the temperature is 40℃~90℃, and the time is 3h~6h.

[0075] The extractant used for extraction and impurity removal includes P204, which is diluted with sulfonated kerosene and has a volume fraction of 20% to 30%. The O / A ratio of the extraction and impurity removal is 0.5:1 to 1.5:1, the number of stages is 6 to 10, the single-stage extraction contact time is 3 min to 6 min, and the phase separation time is 5 min to 20 min.

[0076] (3) The mixed fluorine extractant is extracted with the impurity removal solution to obtain a loaded organic phase and a raffinate;

[0077] The O / A ratio of the extraction is 0.5:1 to 5:1, the number of stages is 2 to 5, the contact time of a single extraction is 5 min to 10 min, and the phase separation time is 5 min to 30 min.

[0078] (4) The loaded organic phase is regenerated and recycled: the loaded organic phase is acid-washed to obtain an acid washing solution; the acid washing solution is back-extracted using an inorganic aluminum salt solution, and the resulting organic phase is treated with iron soap to obtain an iron soap organic phase; the iron soap organic phase is washed with water to realize the regeneration and recycling of the loaded organic phase.

[0079] The pickling is carried out using sulfuric acid with a concentration of 0.01 mol / L to 0.5 mol / L, with an O / A ratio of 10:1 to 30:1 and a number of stages from 1 to 5.

[0080] The inorganic aluminum salt solution has an aluminum ion concentration of 3 g / L to 15 g / L; the O / A ratio of the back-extraction is 10:1 to 20:1, the contact time is 5 min to 10 min, and the number of stages is 2 to 4.

[0081] The iron soap agent used in the iron soap treatment is a ferric sulfate solution with an iron ion concentration of 1 g / L to 10 g / L. The O / A ratio of the iron soap treatment is 10:1 to 20:1, the contact time is 5 min to 10 min, and the number of stages is 1 to 3.

[0082] The O / A ratio of the water washing is 10:1 to 40:1, and the number of stages is 1 to 3.

[0083] Unless otherwise specified, the acid leaching, extraction, and washing operations in this invention are all countercurrent operations; and the contact time is a single-stage contact time.

[0084] Generally, the main components of ternary black powder include 20wt%~35wt% Ni, 6wt%~12wt% Co, 5wt%~15wt% Mn, 4wt%~6wt% Li, 0.5wt%~2.5wt% Fe, 1wt%~4wt% Al, 1wt%~3wt% fluorine, 8wt%~15wt% C, and 0.2wt%~1wt% phosphorus. To clearly illustrate the technical solution of this invention, in the following specific embodiment, the main components of the ternary black powder are: 26wt% Ni, 4.7wt% Co, 6.45wt% Mn, 4.8wt% Li, 1.08wt% Fe, 4.74wt% Al, 2.25wt% F, 12.3wt% C, 0.52wt% phosphorus, and 0.36wt% silicon.

[0085] Example 1

[0086] This embodiment provides a method for defluorination during the recycling of ternary lithium waste, the method comprising the following steps:

[0087] (1) The ternary black powder is reduced and roasted in a nitrogen atmosphere to obtain lithium extraction slag (mainly nickel, cobalt and manganese high-valence oxides); the lithium extraction slag is reduced and acid leached to obtain leachate (containing nickel, cobalt and manganese main metals and impurities such as iron, aluminum, silicon, phosphorus and fluorine).

[0088] The reduction roasting temperature is 650℃, the mass of coke powder is 12% of ternary black powder, and the reduction roasting time is 90min.

[0089] The reducing agent used in the reducing acid leaching is hydrogen peroxide; the amount of reducing agent used is 1.1 times the theoretical amount.

[0090] The acid used in the reducing acid leaching includes sulfuric acid (98 wt%); the amount of sulfuric acid used is 1.1 times the theoretical amount.

[0091] The liquid-to-solid ratio (mL / g) of the reducing acid leaching is 6:1, the temperature is 80℃, and the time is 6h.

[0092] The leachate comprises 52 g / L Ni, 9.4 g / L Co, 12.9 g / L Mn, 2.17 g / L Fe, 9.48 g / L Al, and 4.5 g / L F, and has a pH of 1.5.

[0093] (2) The leachate is neutralized and impurities are removed to obtain a neutralized filtrate and a neutralized residue; the neutralized filtrate is extracted and impurities are removed to obtain a purified solution with a fluorine content of 238 mg / L;

[0094] The neutralizing agent used for neutralization and impurity removal is calcium hydroxide; the pH value for neutralization and impurity removal is 5, the temperature is 70℃, and the time is 4h; after neutralization and impurity removal, the iron and aluminum content in the neutralized filtrate is reduced to below 0.1mg / L, and the fluorine content is reduced to 245mg / L;

[0095] The extractant used for extraction and impurity removal includes P204, which is diluted with sulfonated kerosene and has a volume fraction of 25%. The O / A ratio of the extraction and impurity removal is 1:1, the number of stages is 8, the single-stage extraction contact time is 5 min, and the phase separation time is 15 min.

[0096] (3) The mixed fluorine extractant (HT-019, Hunan Jinzhihe Technology Co., Ltd.) is used to extract the impurity removal solution to obtain the loaded organic phase and the raffinate;

[0097] The extraction has an O / A ratio of 2:1, a number of stages of 3, a contact time of 6 min for a single extraction, and a phase separation time of 20 min.

[0098] (4) The loaded organic phase is regenerated and recycled: the loaded organic phase is acid-washed to obtain an acid washing solution; the acid washing solution is back-extracted using an inorganic aluminum salt solution, and the resulting organic phase is treated with iron soap to obtain an iron soap organic phase; the iron soap organic phase is washed with water to realize the regeneration and recycling of the loaded organic phase.

[0099] The pickling is carried out using sulfuric acid with a concentration of 0.1 mol / L, the pickling O / A ratio is 30:1, and the number of stages is 2.

[0100] The inorganic aluminum salt solution is an aluminum sulfate solution with an aluminum ion concentration of 5 g / L; the O / A ratio of the back-extraction is 15:1, the contact time is 9 min, and the number of stages is 2.

[0101] The iron soap agent used in the iron soap treatment is a ferric sulfate solution with an iron ion concentration of 5 g / L. The O / A ratio of the iron soap treatment is 15:1, the contact time is 9 min, and the number of stages is 1.

[0102] The water washing process has an O / A ratio of 30:1 and is performed in one stage to wash away entrained iron and aluminum ions.

[0103] Example 2

[0104] This embodiment provides a method for defluorination during the recycling of ternary lithium waste, the method comprising the following steps:

[0105] (1) The ternary black powder is reduced and roasted in a nitrogen atmosphere to obtain lithium extraction slag (mainly nickel, cobalt and manganese high-valence oxides); the lithium extraction slag is reduced and acid leached to obtain leachate (containing nickel, cobalt and manganese main metals and impurities such as iron, aluminum, silicon, phosphorus and fluorine).

[0106] The reduction roasting temperature is 600℃, the mass of coke powder is 10% of ternary black powder, and the reduction roasting time is 60min.

[0107] The reducing agent used in the reducing acid leaching is hydrogen peroxide; the amount of reducing agent used is 1.05 times the theoretical amount.

[0108] The acid used in the reducing acid leaching includes sulfuric acid (98 wt%); the amount of sulfuric acid used is 1.05 times the theoretical amount.

[0109] The liquid-to-solid ratio (mL / g) of the reducing acid leaching is 4:1, the temperature is 60℃, and the time is 3h.

[0110] (2) The leachate is neutralized and impurities are removed to obtain a neutralized filtrate and a neutralized residue; the neutralized filtrate is extracted and impurities are removed to obtain an impurity-removed solution;

[0111] The neutralizing agent used for neutralization and impurity removal is calcium hydroxide; the pH value for neutralization and impurity removal is 4, the temperature is 40℃, and the time is 3h.

[0112] The extractant used for extraction and impurity removal includes P204, which is diluted with sulfonated kerosene and has a volume fraction of 25%. The O / A ratio of the extraction and impurity removal is 0.5:1, the number of stages is 6, the single-stage extraction contact time is 3 min, and the phase separation time is 5 min.

[0113] (3) The mixed fluorine extractant (HT-019, Hunan Jinzhihe Technology Co., Ltd.) is used to extract the impurity removal solution to obtain the loaded organic phase and the raffinate;

[0114] The O / A ratio of the extraction is 0.5:1, the number of stages is 2, the contact time of a single extraction is 5 min, and the phase separation time is 5 min.

[0115] (4) The loaded organic phase is regenerated and recycled: the loaded organic phase is acid-washed to obtain an acid washing solution; the acid washing solution is back-extracted using an inorganic aluminum salt solution, and the resulting organic phase is treated with iron soap to obtain an iron soap organic phase; the iron soap organic phase is washed with water to realize the regeneration and recycling of the loaded organic phase.

[0116] The pickling was carried out using sulfuric acid with a concentration of 0.01 mol / L, with an O / A ratio of 10:1 and a pickling stage of 1.

[0117] The inorganic aluminum salt solution is an aluminum sulfate solution with an aluminum ion concentration of 3 g / L; the O / A ratio of the back-extraction is 10:1, the contact time is 5 min, and the number of stages is 2.

[0118] The iron soap agent used in the iron soap treatment is a ferric sulfate solution with an iron ion concentration of 1 g / L. The O / A ratio of the iron soap treatment is 10:1, the contact time is 5 min, and the number of stages is 1.

[0119] The water washing process has an O / A ratio of 10:1 and is performed in one stage to wash away entrained iron and aluminum ions.

[0120] Example 3

[0121] This embodiment provides a method for defluorination during the recycling of ternary lithium waste, the method comprising the following steps:

[0122] (1) The ternary black powder is reduced and roasted in a nitrogen atmosphere to obtain lithium extraction slag (mainly nickel, cobalt and manganese high-valence oxides); the lithium extraction slag is reduced and acid leached to obtain leachate (containing nickel, cobalt and manganese main metals and impurities such as iron, aluminum, silicon, phosphorus and fluorine).

[0123] The reduction roasting temperature is 700℃, the mass of coke powder is 15% of ternary black powder, and the reduction roasting time is 120min.

[0124] The reducing agent used in the reducing acid leaching is hydrogen peroxide; the amount of reducing agent used is 1.2 times the theoretical amount.

[0125] The acid used in the reducing acid leaching includes sulfuric acid (98 wt%); the amount of sulfuric acid used is 1.2 times the theoretical amount.

[0126] The liquid-to-solid ratio (mL / g) of the reducing acid leaching is 8:1, the temperature is 90℃, and the time is 6h.

[0127] (2) The leachate is neutralized and impurities are removed to obtain a neutralized filtrate and a neutralized residue; the neutralized filtrate is extracted and impurities are removed to obtain an impurity-removed solution;

[0128] The neutralizing agent used for neutralization and impurity removal is calcium hydroxide; the pH value for neutralization and impurity removal is 6, the temperature is 90℃, and the time is 6h.

[0129] The extractant used for extraction and impurity removal includes P204, which is diluted with sulfonated kerosene and has a volume fraction of 25%. The O / A ratio of the extraction and impurity removal is 1.5:1, the number of stages is 10, the single-stage extraction contact time is 6 min, and the phase separation time is 20 min.

[0130] (3) The mixed fluorine extractant (HT-019, Hunan Jinzhihe Technology Co., Ltd.) is used to extract the impurity removal solution to obtain the loaded organic phase and the raffinate;

[0131] The extraction has an O / A ratio of 5:1, five stages, a contact time of 10 min for a single extraction, and a phase separation time of 30 min.

[0132] (4) The loaded organic phase is regenerated and recycled: the loaded organic phase is acid-washed to obtain an acid washing solution; the acid washing solution is back-extracted using an inorganic aluminum salt solution, and the resulting organic phase is treated with iron soap to obtain an iron soap organic phase; the iron soap organic phase is washed with water to realize the regeneration and recycling of the loaded organic phase.

[0133] The pickling is carried out using sulfuric acid with a concentration of 0.5 mol / L, the pickling O / A ratio is 30:1, and the number of pickling stages is 5.

[0134] The inorganic aluminum salt solution is an aluminum sulfate solution with an aluminum ion concentration of 15 g / L; the O / A ratio of the back-extraction is 20:1, the contact time is 10 min, and the number of stages is 4.

[0135] The iron soap agent used in the iron soap treatment is a ferric sulfate solution with an iron ion concentration of 1 g / L. The O / A ratio of the iron soap treatment is 20:1, the contact time is 10 min, and the number of stages is 3.

[0136] The water washing process has an O / A ratio of 40:1 and consists of three stages to wash away entrained iron and aluminum ions.

[0137] Example 4

[0138] This embodiment provides a method for defluorination during the recycling of ternary waste materials. Except for the pH value of 3.5 for neutralization and impurity removal, the method is the same as that in Embodiment 1.

[0139] Example 5

[0140] This embodiment provides a method for defluorination during the recycling of ternary waste materials. Except for the pH value of 6.5 for neutralization and impurity removal, the method is the same as in Example 1.

[0141] Example 6

[0142] This embodiment provides a method for defluorination during the recycling of ternary waste. Except for the O / A ratio of 0.1:1 extracted in step (3), the rest is the same as in Example 1.

[0143] Example 7

[0144] This embodiment provides a method for defluorination during the recycling of ternary waste. Except for the O / A ratio of 6:1 extracted in step (3), the rest is the same as in Example 1.

[0145] Comparative Example 1

[0146] This comparative example provides a method for defluorination during the recycling of ternary waste. Except for adding 1.2 times the theoretical dosage of aluminum hydroxide as a defluorinating agent during neutralization and impurity removal, the rest is the same as in Example 1.

[0147] This comparative example uses aluminum hydroxide for defluorination, which increases the amount of neutralization slag and the loss of nickel and cobalt in the neutralization slag. It also introduces a large amount of aluminum impurities, increasing the burden on subsequent impurity removal processes.

[0148] Performance Characterization

[0149] The fluorine content, total nickel recovery rate, and total cobalt recovery rate of the raffinate obtained by the methods provided in the above embodiments and comparative examples were tested, and the results are shown in Table 1. The total nickel recovery rate refers to the percentage of nickel in the raffinate relative to the total nickel in the ternary black powder; the total cobalt recovery rate refers to the percentage of cobalt in the raffinate relative to the total cobalt in the ternary black powder.

[0150] Table 1

[0151]

[0152] As can be seen from Examples 1 to 3 in Table 1, the two-stage process combining neutralization precipitation for crude fluoride removal and extraction for deep fluoride removal provided by the present invention can achieve efficient removal of fluoride while ensuring a high recovery rate of valuable metals such as nickel and cobalt.

[0153] A comparison of Examples 4 and 5 with Example 1 shows that when the pH value for neutralization and impurity removal is too low, the iron and aluminum ions in the leachate cannot fully form fluoride complexes, resulting in a fluoride content in the neutralization filtrate exceeding 500 mg / L. This significantly increases the defluorination load in the subsequent extraction process, and the final fluoride content in the raffinate reaches as high as 50.0 mg / L, failing to meet the requirements for deep defluorination. At the same time, an excessively low pH value also leads to incomplete precipitation of some metal ions, resulting in a decrease in the total recovery rate of nickel and cobalt. When the pH value for neutralization and impurity removal is too high, although the precipitation and removal effect of fluoride is better, excessive alkali will cause valuable metal ions such as nickel and cobalt to form hydroxide precipitates that enter the slag phase, resulting in a decrease in the total recovery rate of nickel and cobalt.

[0154] A comparison of Examples 6 and 7 with Example 1 shows that when the O / A ratio is too low, the organic phase extraction capacity is insufficient, and the fluorine in the impurity removal solution cannot be fully extracted and separated. When the O / A ratio is too high, although deep removal of fluorine can be achieved, it will result in excessive use of extractant, increase the process operating cost, and also increase the load on subsequent organic phase regeneration.

[0155] As can be seen from the comparison between Comparative Example 1 and Example 1, although the addition of defluorinating agent can reduce the fluoride content of the raffinate to 5.0 mg / L and achieve deep defluorination, it will introduce new impurity ions. In addition, the defluorinating agent will co-precipitate with valuable metal ions such as nickel and cobalt, resulting in the total recovery rate of nickel dropping to 93.0% and the total recovery rate of cobalt dropping to 95.0%, which significantly reduces the recovery efficiency of valuable metals in ternary waste.

[0156] In summary, this invention addresses the defluorination requirements in the ternary waste recycling process by employing a two-stage process combining neutralization precipitation for coarse defluorination and extraction for deep defluorination. First, ternary black powder is reduced and roasted to obtain lithium extraction slag. This slag is then subjected to reducing acid leaching to obtain a fluorinated leachate. The leachate is then subjected to neutralization and extraction for further impurity removal. During this process, the complexation and precipitation of iron and aluminum ions inherent in the leachate raw material, along with the chemical precipitation introduced by the neutralization step, achieves efficient preliminary removal of fluoride without the need for additional specialized defluorinating agents. This reduces the fluoride content in the leachate from several g / L to below 500 mg / L, yielding a purified solution. Subsequently, a fluorine extractant is mixed with the purified solution for deep defluorination, resulting in a loaded organic phase and a raffinate with a fluoride content reduced to below 10 mg / L. Simultaneously, the loaded organic phase is regenerated and recycled back to the extraction process, forming a stable closed-loop regeneration and recycling system for the extractant.

[0157] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for removing fluorine in a ternary scrap recycling process, characterized by, The method includes the following steps: S1. Ternary black powder is subjected to reduction roasting to obtain lithium extraction residue; the lithium extraction residue is subjected to reduction acid leaching to obtain leachate; S2. The leachate is neutralized and impurities are removed to obtain a neutralized filtrate and a neutralized residue; the neutralized filtrate is extracted and impurities are removed to obtain a purified solution with a fluorine content of less than 500 mg / L. S3. The mixed fluorine extractant is extracted with the impurity removal solution to obtain a loaded organic phase and raffinate; The supported organic phase is regenerated and recycled.

2. The method according to claim 1, characterized in that, The reducing agent used in the reducing acid leaching includes any one or a combination of at least two of hydrogen peroxide, sodium sulfite, or sodium metabisulfite. And / or, the acid used in the reducing acid leaching includes sulfuric acid.

3. The method according to claim 1 or 2, characterized in that, The content of F in the leachate is 2g / L to 10g / L.

4. The method according to any one of claims 1 to 3, characterized in that, The neutralizing agent used for neutralization and impurity removal includes any one or a combination of at least two of liquid alkali, lime milk, sodium carbonate, or calcium hydroxide.

5. The method according to any one of claims 1 to 4, characterized in that, The pH value for neutralization and impurity removal is 4-6; And / or, the neutralization and impurity removal temperature is 40℃~90℃; And / or, the neutralization and impurity removal time is 3h~6h.

6. The method according to any one of claims 1 to 5, characterized in that, The extractant used for extraction and impurity removal includes P2O4.

7. The method according to any one of claims 1 to 6, characterized in that, The O / A ratio of the extracted material is 0.5:1 to 5:1; And / or, the number of extraction stages is 2 to 5; And / or, the contact time for a single extraction is 5 min to 10 min, and the phase separation time is 5 min to 30 min.

8. The method according to any one of claims 1 to 7, characterized in that, The regeneration cycle includes: acid washing of the loaded organic phase to obtain an acid washing solution; back-extraction of the acid washing solution using an inorganic aluminum salt solution, followed by iron soap treatment of the obtained organic phase to obtain an iron soap organic phase; and washing of the iron soap organic phase with water to achieve the regeneration cycle of the loaded organic phase.

9. The method of claim 8, wherein, The pickling is carried out using sulfuric acid with a concentration of 0.01 mol / L to 0.5 mol / L, with an O / A ratio of 10:1 to 30:1 and a number of stages from 1 to 5. And / or, the inorganic aluminum salt solution is an aluminum sulfate solution with an aluminum ion concentration of 3 g / L to 15 g / L; And / or, the O / A ratio of the back-extraction is 10:1 to 20:1, the contact time is 5 min to 10 min, and the number of stages is 2 to 4.

10. The method according to claim 8 or 9, characterized in that, The iron soap agent used in the iron soap treatment is a ferric sulfate solution with an iron ion concentration of 1 g / L to 10 g / L; And / or, the O / A ratio of the iron soap treatment is 10:1 to 20:1, the contact time is 5 min to 10 min, and the number of stages is 1 to 3; And / or, the O / A ratio of the water wash is 10:1 to 40:1, and the number of stages is 1 to 3.

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