Method and composition for removing iron and aluminum from a mixed solution recovered from a battery

Abstract

A method for removing iron and aluminum from a mixed solution in battery recycling, comprising the following steps: adding at least one of a sodium source and a potassium source, a fluorine source to the solution to be treated, and adjusting the pH to 2.5-3.2 to obtain a mixed solution; heating and aging the mixed solution; filtering the mixed solution after heating and aging. The method is simple in process and can remove iron and aluminum elements in the mixed solution in battery recycling at one time.

Description

Technical Field

[0001] This invention relates to the field of battery recycling technology, and in particular to a method and composition for removing iron and aluminum from a battery recycling mixture. Background Technology

[0002] With the development of power battery technology, battery recycling technology is receiving increasing attention. In the field of ternary lithium battery recycling, the waste battery is first prepared into a mixed solution containing multiple elements such as nickel, cobalt, lithium, and manganese to facilitate the subsequent recovery of each element. Nickel, cobalt, lithium, and manganese in this mixed solution all have high recycling value. However, the aforementioned mixed solution also contains a large amount of Al. 3+ and Fe 3+ Impurities (A) l3+ and Fe 3+ (If the total concentration is greater than 3 g / L), in order to obtain a pure mixed solution containing elements such as nickel, cobalt, lithium, and manganese, it is necessary to remove Al from the mixed solution. 3+ and Fe 3+ .

[0003] Common ones besides Al 3+ and Fe 3+ Methods include neutralization hydrolysis, sodium ferrous sulfate method, goethite method, and hematite method. The sodium ferrous sulfate method requires that the mixed solution contain sodium (Na). + Furthermore, the pH range is 1.6-2.0, which is insufficient to remove Al. 3+ The goethite process requires Fe 3+ The concentration should not exceed 1 g / L, and the generated ferric hydroxide colloid is highly viscous, making filtration difficult; the hematite method requires high temperature and high pressure (160℃-200℃) for the reaction. To avoid the loss of valuable metals Ni / Co / Li / Mn, while simultaneously achieving Al… 3+ and Fe 3+ For impurity removal, based on the actual conditions of the Ni / Co / Mn / Li mixed solution, neutralization hydrolysis is often used in waste battery recycling lines. In actual application of the neutralization hydrolysis method, the first-stage impurity removal (pH=3~3.5) is not very effective in removing Al, requiring a second-stage impurity removal and dealuminization. However, at high pH (pH>5), valuable metals such as cobalt and nickel will undergo large-scale hydrolysis and precipitation. The residue from the second-stage impurity removal needs to be back-dissolved into the main system, resulting in waste of auxiliary materials. Al cannot be effectively removed in one stage.

[0004] Therefore, there is an urgent need for a simple and feasible industrial-scale process to recover Al from battery mixed solutions. 3+ and Fe 3+ Highly efficient removal of impurities. Summary of the Invention

[0005] This invention provides a method and composition for removing iron and aluminum from a battery recycling solution. The method is simple and can remove iron and aluminum from the battery recycling solution in one step.

[0006] This invention provides a method for removing iron and aluminum from a battery recovery mixture, comprising the following steps: Add at least one of a sodium source and a potassium source, a fluorine source, and adjust the pH to 2.5-3.2 to the solution to be treated to obtain a mixed solution; The mixed solution is then subjected to heating and aging treatment; The mixed solution after heating and aging is filtered.

[0007] Furthermore, the sodium source is one or more of sodium hydroxide and sodium fluoride; the potassium source is one or more of potassium hydroxide and potassium fluoride.

[0008] Furthermore, the fluorine source is one or more of sodium fluoride, potassium fluoride, and hydrofluoric acid.

[0009] Furthermore, the pH of the solution to be treated is adjusted using sodium hydroxide and / or potassium hydroxide.

[0010] Furthermore, when adding the fluorine source, it should be done in molar amounts according to n. Al :n F The fluorine source is added at a ratio of 1:6, which is 0.9 to 1.2 times the theoretical amount, where nAl is the molar amount of Al in the mixed solution to be treated.

[0011] Furthermore, when adjusting the pH of the solution to be treated, the concentration of added sodium hydroxide and / or potassium hydroxide is 12%-32% by mass fraction.

[0012] Furthermore, during heating, the heating temperature is 50-70℃, the holding time is 0.5-2h, and stirring is performed.

[0013] Furthermore, the aging time is 0.5-2 hours.

[0014] Furthermore, after obtaining filter residue through filtration, the method also includes stirring and rinsing the filter residue.

[0015] Furthermore, after heating and aging, trivalent aluminum precipitates as Na3AlF6 and / or K3AlF6, and trivalent iron precipitates as Fe(OH)3.

[0016] The present invention also provides a composition for removing iron and aluminum from a battery recovery mixed solution, comprising at least one of a sodium source and a potassium source, a fluorine source, and a pH adjuster; in molar amounts, according to nAl :n F =1:6, with 0.9 to 1.2 times the theoretical amount of fluorine source added, where n Al The amount of Al in the mixed solution to be treated is given by the pH adjuster to adjust the pH of the mixed solution to 2.5-3.2.

[0017] In summary, this invention, by controlling a suitable pH and a compound fluorine source, allows aluminum ions to be removed by precipitation of aluminum fluoride crystals such as Na3AlF6 and K3AlF6, and iron ions to be removed by precipitation of iron hydroxide. This achieves qualified removal of iron and aluminum from the solution to be treated in one step, while simultaneously removing a portion of the original fluorine element in the solution, reducing the pressure on downstream defluorination. The process is simple and suitable for production line operation.

[0018] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below. Detailed Implementation

[0019] To further illustrate the technical means and effects adopted by the present invention in order to achieve the intended purpose, the present invention will be described in detail below with reference to preferred embodiments.

[0020] This invention provides a method and composition for removing iron and aluminum from a battery recycling solution. The method is simple and can remove iron and aluminum from the battery recycling solution in one step.

[0021] An embodiment of the present invention provides a method for removing iron and aluminum from a battery recovery mixed solution, comprising the following steps: S1: Add at least one of the sodium and potassium sources, a fluorine source, to the solution to be treated, and adjust the pH to 2.5-3.2.

[0022] When performing step S1, it is necessary to analyze the composition of the solution to be treated in order to determine the amount of each substance to be added.

[0023] In this embodiment, the added sodium or potassium source can be one or more of sodium hydroxide, potassium hydroxide, sodium fluoride, and potassium fluoride. The added fluorine source can be one or more of sodium fluoride, potassium fluoride, and hydrofluoric acid. Understandably, sodium fluoride and potassium fluoride can also be compounds used as fluorine sources, as well as compounds used as sodium or potassium salts.

[0024] When adjusting the pH, sodium hydroxide and / or potassium hydroxide can be used to adjust the pH of the solution to be treated. These compounds can facilitate pH adjustment relatively easily, while simultaneously providing a sodium or potassium source to the solution and preventing the introduction of new impurities. The pH values ​​can be 2.5, 2.7, 2.9, 3.0, 3.1, 3.2, etc.

[0025] Furthermore, in this embodiment, when adding the fluorine source, the molar amount of aluminum in the solution to be treated can be detected first, and then, based on the molar amount, according to n... Al :n F =1:6, with 0.9 to 1.2 times the theoretical amount of fluorine source added, where n Al This represents the molar amount of Al in the solution to be treated.

[0026] After adding at least one of a sodium source and a potassium source, a fluorine source, and adjusting the pH to 2.5-3.2, the Al in the solution to be recovered... 3+ and Fe 3+ The impurities will undergo the following reactions throughout the system: Al 3+ + 6F - + 3Na + → Na3AlF6 (Formula 1) Al 3+ + 6F - +3K + → K3AlF6 (Equation 2) Fe 3+ + 3OH - → Fe(OH)3 (Formula 3) That is, trivalent aluminum will precipitate as Na3AlF6 and / or K3AlF6, while trivalent iron will precipitate as Fe(OH)3.

[0027] It should be noted that since the role of sodium or potassium in the mixed solution is to combine with fluorine and trivalent aluminum to form a precipitate, in step S1, only sodium or potassium source can be added, or both sodium and potassium source can be added simultaneously.

[0028] It is worth noting that, in this embodiment, pH adjustment is achieved by adding sodium hydroxide and / or potassium hydroxide. Simultaneously, sodium and / or potassium sources are added. The amount of sodium and / or potassium in the sodium hydroxide and / or potassium hydroxide used for pH adjustment far exceeds the amount of sodium and / or potassium sources used for aluminum precipitation. Therefore, it is unnecessary to calculate the amount of sodium and / or potassium sources; it is sufficient to ensure that the pH of the solution to be treated is within a suitable range.

[0029] Furthermore, to facilitate pH adjustment of the solution to be treated, the concentration of added sodium hydroxide and / or potassium hydroxide can be 12%-32% by mass fraction. When both sodium hydroxide and potassium hydroxide are added simultaneously, their concentrations can both be 12%-32%.

[0030] S2: Heating and aging the mixed solution from step S1.

[0031] In this embodiment, after adding at least one of a sodium source and a potassium source, a fluorine source, and adjusting the pH to 2.5-3.2 to the solution to be treated, the mixed solution can be heated to a temperature of 50-70°C and maintained at that temperature for 0.5-2 hours to allow the reaction to proceed. Stirring can be performed during the reaction to accelerate its progress.

[0032] After the reaction is complete, the mixture is aged for 0.5-2 hours.

[0033] S3: Filter the product obtained in S2.

[0034] During filtration, pressure filtration can be used to separate the precipitate from the liquid, resulting in filter residue and the purified liquid.

[0035] Furthermore, the method also includes stirring and rinsing the filter residue to recover elements such as nickel, cobalt, lithium, and manganese adhering to the filter residue.

[0036] When washing, the solid content can be 20%-40%, and the washing time is 0.5-2 hours.

[0037] During rinsing, the liquid-to-solid ratio can be 2:1 to 5:1.

[0038] In summary, by controlling the appropriate pH and compounding the fluorine source, aluminum ions are removed by precipitation of aluminum fluoride crystals such as Na3AlF6 and K3AlF6, and iron ions are removed by precipitation of iron hydroxide. This achieves qualified removal of iron and aluminum from the solution to be treated in one step, while simultaneously removing a portion of the original fluorine element in the solution to be treated, reducing the pressure on downstream defluorination. The process is simple and suitable for production line operation.

[0039] The present invention also provides a composition for removing iron and aluminum from a battery recovery mixed solution, comprising at least one of a sodium source and a potassium source, a fluorine source, and a pH adjuster; in molar amounts, according to n Al :n F =1:6, with 0.9 to 1.2 times the theoretical amount of fluorine source added, where n Al The amount of Al in the mixed solution to be treated is given by the pH adjuster to adjust the pH of the mixed solution to 2.5-3.2.

[0040] The above method will be described below with specific examples: Example 1: S1: Prepare a mixture of sodium fluoride in equal theoretical amounts based on the Al content in the solution to be treated. The main components in the solution to be treated are: Ni: 55.78 g / L, Co: 24.24 g / L, Mn: 19 g / L, Fe: 3.58 g / L, Al: 6.62 g / L, F: 4.48 g / L; and add 32% sodium hydroxide solution until the pH reaches 3. S2: Stir at 60℃ for 1 hour, then turn off the stirring and let it age for 1 hour; S3: Pressure filtration, the solid content of the filter residue is 25%, the washing time is 1 hour, and the liquid-to-solid ratio of the rinsing is 3:1.

[0041] Under the conditions of Example 1, the treated liquid contained Fe: 3 ppm, Al: 1 ppm, and F: 637 ppm, exhibiting excellent filtration performance (0.13 m). 3 / (m 2 The iron and aluminum impurities in the slag were removed to a standard level of 0.01% Ni, 0.03% Co, and 0.01% Mn, and the content of valuable metals in the slag met the scrapping standard.

[0042] Example 2: S1: Prepare a mixture of potassium fluoride at one times the theoretical amount based on the Al content in the solution to be treated. The main components in the solution to be treated are: Ni: 55.78 g / L, Co: 24.24 g / L, Mn: 19 g / L, Fe: 3.58 g / L, Al: 6.62 g / L, F: 4.48 g / L; and add 32% potassium hydroxide solution dropwise until pH=3. S2: Stir at 60℃ for 1 hour, then turn off the stirring and let it age for 1 hour; S3: Pressure filtration, the solid content of the filter residue is 25%, the washing time is 1 hour, and the liquid-to-solid ratio of the rinsing is 3:1.

[0043] Under the conditions of Example 2, the treated liquid contained Fe: 4 ppm, Al: 1 ppm, and F: 671 ppm, exhibiting excellent filtration performance (0.133 m). 3 / (m 2 The iron and aluminum impurities in the slag were removed to a standard level of 0.01% Ni, 0.04% Co, and 0.01% Mn, and the content of valuable metals in the slag met the scrapping standard.

[0044] Example 3: S1: Prepare a mixture of potassium fluoride at one times the theoretical amount based on the Al content in the solution to be treated. The main components of the solution to be treated are: Ni: 55.78 g / L, Co: 24.24 g / L, Mn: 19 g / L, Fe: 3.58 g / L, Al: 6.62 g / L, F: 4.48 g / L; and add 32% sodium hydroxide solution dropwise until pH=3. S2: React at 60℃ for 1 hour, then turn off the stirring and let it age for 1 hour; S3: Pressure filtration, the solid content of the filter residue is 25%, the washing time is 1 hour, and the liquid-to-solid ratio of the rinsing is 3:1.

[0045] Under the conditions of Example 3, the treated liquid contained Fe: 3 ppm, Al: 1 ppm, and F: 589 ppm, exhibiting excellent filtration performance (0.129 m). 3 / (m 2 The iron and aluminum impurities in the slag were removed to a standard level of 0.01% Ni, 0.02% Co, and 0.02% Mn, and the content of valuable metals in the slag met the scrapping standard.

[0046] Example 4: S1: Prepare a mixture of sodium fluoride in equal theoretical amounts based on the Al content in the solution to be treated. The main components of the solution to be treated are: Ni: 55.78 g / L, Co: 24.24 g / L, Mn: 19 g / L, Fe: 3.58 g / L, Al: 6.62 g / L, F: 4.48 g / L; and add 32% sodium hydroxide solution dropwise until pH=2.5. S2: React at 60℃ for 1 hour, then turn off the stirring and let it age for 1 hour; S3: Pressure filtration, the solid content of the filter residue is 25%, the washing time is 1 hour, and the liquid-to-solid ratio of the rinsing is 3:1.

[0047] Under the conditions of Example 4, the treated liquid contained Fe: 6 ppm, Al: 1 ppm, and F: 564 ppm, exhibiting excellent filtration performance (0.139 m). 3 / (m 2 The iron and aluminum impurities in the slag were removed to a standard level of 0.01% Ni, 0.01% Co, and 0.01% Mn, and the content of valuable metals in the slag met the scrapping standard.

[0048] Example 5: S1: Prepare a mixture of sodium fluoride at 0.8 times the theoretical amount based on the Al content in the solution to be treated. The main components of the solution to be treated are: Ni: 55.78 g / L, Co: 24.24 g / L, Mn: 19 g / L, Fe: 3.58 g / L, Al: 6.62 g / L, F: 4.48 g / L; and add 32% sodium hydroxide solution dropwise until pH=3.2. S2: React at 60℃ for 1 hour, then turn off the stirring and let it age for 1 hour; S3: Pressure filtration, the solid content of the filter residue is 25%, the washing time is 1 hour, and the liquid-to-solid ratio of the rinsing is 3:1.

[0049] Under the conditions of Example 5, the treated liquid contained Fe: 2 ppm, Al: 1 ppm, and F: 534 ppm, exhibiting excellent filtration performance (0.137 m). 3 / (m 2 The iron and aluminum impurities in the slag were removed to a standard level of 0.04% Ni, 0.06% Co, and 0.07% Mn, and the content of valuable metals in the slag met the scrapping standard.

[0050] Example 6: S1: Prepare a mixture of sodium fluoride in equal theoretical amounts based on the Al content in the solution to be treated. The main components of the solution to be treated are: Ni: 55.78 g / L, Co: 24.24 g / L, Mn: 19 g / L, Fe: 3.58 g / L, Al: 6.62 g / L, F: 4.48 g / L; and add 32% sodium hydroxide solution dropwise until pH=3. S2: React at 60℃ for 1 hour, then turn off the stirring and age for 4 hours; S3: Pressure filtration, the solid content of the filter residue is 25%, the washing time is 1 hour, and the liquid-to-solid ratio of the rinsing is 3:1.

[0051] Under the conditions of Example 6, the treated liquid contained Fe: 2 ppm, Al: 2 ppm, and F: 649 ppm, exhibiting excellent filtration performance (0.221 m). 3 / (m 2 The iron and aluminum impurities in the slag were removed to a standard level of 0.01% Ni, 0.02% Co, and 0.01% Mn, and the content of valuable metals in the slag met the scrapping standard.

[0052] Example 7: S1: Prepare a mixture of sodium fluoride in equal theoretical amounts based on the Al content in the solution to be treated. The main components of the solution to be treated are: Ni: 55.78 g / L, Co: 24.24 g / L, Mn: 19 g / L, Fe: 3.58 g / L, Al: 6.62 g / L, F: 4.48 g / L; and add 32% sodium hydroxide solution dropwise until pH=3. S2: React at 60℃ for 1 hour, then turn off the stirring and age for 0.5 hours; S3: Pressure filtration, the solid content of the filter residue is 25%, the washing time is 1 hour, and the liquid-to-solid ratio of the rinsing is 3:1.

[0053] Under the conditions of Example 6, the treated liquid contained Fe: 3 ppm, Al: 1 ppm, and F: 649 ppm, exhibiting excellent filtration performance (0.09 m). 3 / (m 2 The iron and aluminum impurities in the slag were removed to a standard level of 0.01% Ni, 0.02% Co, and 0.01% Mn, and the content of valuable metals in the slag met the scrapping standard.

[0054] Comparative Example 1: S1: Prepare a mixture of sodium fluoride at 0.5 times the theoretical amount based on the Al content in the solution to be treated. The main components of the solution to be treated are: Ni: 55.78 g / L, Co: 24.24 g / L, Mn: 19 g / L, Fe: 3.58 g / L, Al: 6.62 g / L, F: 4.48 g / L; and add 32% sodium hydroxide solution dropwise until pH=3. S2: React at 60℃ for 1 hour, then turn off the stirring and let it age for 1 hour; S3: Pressure filtration, the solid content of the filter residue is 25%, the washing time is 1 hour, and the liquid-to-solid ratio of the rinsing is 3:1.

[0055] Under the conditions of Comparative Example 1, the treated solution contained Fe: 3 ppm, Al: 34 ppm, and F: 432 ppm. The Al content in the purified solution exceeded the standard, indicating excellent filtration performance (0.131 m). 3 / (m 2 The slag contains 0.01% Ni, 0.02% Co, and 0.01% Mn, and the content of valuable metals in the slag meets the scrapping standard.

[0056] Comparative Example 2: S1: Prepare a mixture of sodium fluoride in equal theoretical amounts based on the Al content in the solution to be treated. The main components of the solution to be treated are: Ni: 55.78 g / L, Co: 24.24 g / L, Mn: 19 g / L, Fe: 3.58 g / L, Al: 6.62 g / L, F: 4.48 g / L; and add 32% sodium hydroxide solution dropwise until the pH reaches 3.5. S2: React at 60℃ for 1 hour, then turn off the stirring and let it age for 1 hour; S3: Pressure filtration, the solid content of the filter residue is 25%, the washing time is 1 hour, and the liquid-to-solid ratio of the rinsing is 3:1.

[0057] Under the conditions of Comparative Example 2, the treated liquid contained Fe: 1 ppm, Al: 1 ppm, and F: 657 ppm, exhibiting excellent filtration performance (0.127 m). 3 / (m 2 The slag contained excessive levels of valuable metals, including Ni (0.21%), Co (0.35%), and Mn (0.27%).

[0058] Comparative Example 3: S1: Prepare a mixture of sodium fluoride in equal theoretical amounts based on the Al content in the solution to be treated. The main components of the solution to be treated are: Ni: 55.78 g / L, Co: 24.24 g / L, Mn: 19 g / L, Fe: 3.58 g / L, Al: 6.62 g / L, F: 4.48 g / L; and add 32% sodium hydroxide solution dropwise until pH=3. S2: React at 60℃ for 1 hour, then turn off the stirring and age for 0.1 hours; S3: Pressure filtration, the solid content of the filter residue is 25%, the washing time is 1 hour, and the liquid-to-solid ratio of the rinsing is 3:1.

[0059] Under the conditions of Comparative Example 3, the treated solution contained Fe: 1 ppm, Al: 2 ppm, and F: 637 ppm, making filtration difficult (0.025 m). 3 / (m 2 The slag contains 0.02% Ni, 0.02% Co, and 0.01% Mn, and the content of valuable metals in the slag meets the scrapping standard.

[0060] Comparative Example 4: S1: Prepare a mixture of sodium fluoride in equal theoretical amounts based on the Al content in the solution to be treated. The main components of the solution to be treated are: Ni: 55.78 g / L, Co: 24.24 g / L, Mn: 19 g / L, Fe: 3.58 g / L, Al: 6.62 g / L, F: 4.48 g / L; and add 32% sodium hydroxide solution dropwise until pH=2. S2: React at 60℃ for 1 hour, then turn off the stirring and let it age for 1 hour; S3: Pressure filtration, the solid content of the filter residue is 25%, the washing time is 1 hour, and the liquid-to-solid ratio of the rinsing is 3:1.

[0061] Under the conditions of Comparative Example 4, the treated liquid contained Fe: 5 ppm, Al: 89 ppm, and F: 677 ppm. Fe and Al impurities exceeded the standards, but the filtration performance was excellent (0.127 m). 3 / (m 2 The slag contains 0.01% Ni, 0.01% Co, and 0.01% Mn, and the content of valuable metals in the slag meets the scrapping standard.

[0062] Table 1 shows a data comparison between the examples and comparative examples. As can be seen from the table, controlling the appropriate fluorine source ratio, pH, and aging time can effectively remove iron and aluminum impurities from the solution to be treated, resulting in qualified slag that can be discarded, achieving one-time removal of iron and aluminum impurities, and exhibiting excellent filtration performance. When the fluorine source ratio is low, qualified Al removal cannot be achieved; when the fluorine source ratio is too high, the auxiliary material cost is high, and the pressure on the downstream defluorination process is significant, resulting in insufficient economic efficiency; if the pH is too low, Fe / Al impurities exceed the standard; if the pH is too high, valuable elements in the slag exceed the standard; if the aging time is too short, the filtration performance is poor; if the aging time is too long, the economic benefits are insufficient.

[0063] Table 1. Data Comparison Between the Implementing and Comparing Columns

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for removing iron and aluminum from a battery recovery mixture, characterized in that: Includes the following steps: Add at least one of a sodium source and a potassium source, a fluorine source, and adjust the pH to 2.5-3.2 to the solution to be treated to obtain a mixed solution; The mixed solution is then subjected to heating and aging treatment; The mixed solution after heating and aging is filtered.

2. The method for removing iron and aluminum from a battery recovery mixture according to claim 1, characterized in that: The sodium source is one or more of sodium hydroxide and sodium fluoride; the potassium source is one or more of potassium hydroxide and potassium fluoride.

3. The method for removing iron and aluminum from a battery recovery mixture according to claim 1, characterized in that: The fluorine source is one or more of sodium fluoride, potassium fluoride, and hydrofluoric acid.

4. The method for removing iron and aluminum from a battery recovery mixture according to claim 1, characterized in that: The pH of the solution to be treated is adjusted using sodium hydroxide and / or potassium hydroxide.

5. The method for removing iron and aluminum from a battery recovery mixture according to claim 1, characterized in that: When adding the fluorine source, it should be done in molar amounts according to n. Al :n F =1:6, with 0.9 to 1.2 times the theoretical amount of fluorine source added, where n Al This represents the molar amount of Al element in the mixed solution to be treated.

6. The method for removing iron and aluminum from a battery recovery mixture according to claim 1, characterized in that: When adjusting the pH of the solution to be treated, the concentration of added sodium hydroxide and / or potassium hydroxide is 12%-32% by mass fraction.

7. The method for removing iron and aluminum from a battery recovery mixture according to claim 1, characterized in that: During heating, the heating temperature is 50-70℃, the holding time is 0.5-2 hours, and stirring is performed. And / or, the aging time is 0.5-2 hours.

8. The method for removing iron and aluminum from a battery recovery mixture according to claim 1, characterized in that: After obtaining filter residue through filtration, the method also includes stirring and rinsing the filter residue.

9. The method for removing iron and aluminum from a battery recovery mixture according to claim 8, characterized in that: After heating and aging, trivalent aluminum precipitates as Na3AlF6 and / or K3AlF6, and trivalent iron precipitates as Fe(OH)3.

10. A composition for removing iron and aluminum from a battery recovery mixed solution, characterized in that: Includes at least one of a sodium source and a potassium source, a fluorine source, and a pH adjuster; in molar amounts, according to n Al :n F =1:6, with 0.9 to 1.2 times the theoretical amount of fluorine source added, where n Al The amount of Al in the mixed solution to be treated is given by the pH adjuster to adjust the pH of the mixed solution to 2.5-3.2.

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