A recycling method of waste lithium batteries applied to lithium battery full-chain integration

Abstract

The present disclosure belongs to the technical field of lithium battery recycling, and particularly relates to a recycling method of waste lithium batteries applied to the whole-chain integration of lithium batteries. Since the valuable metals (such as nickel, cobalt and manganese) in the waste lithium battery powder are insoluble in alkali, the aluminum in the waste lithium battery powder can be removed through one-time alkali leaching, the aluminum-containing leaching solution is mixed with glycine, and the selective leaching of copper and aluminum is realized by the coordination of glycine and copper ions. Through the recycling method provided by the present disclosure, copper and aluminum can be efficiently and low-costly removed, and the recovery rate of valuable metals is improved.

Description

Technical Field

[0001] This disclosure pertains to the field of lithium battery recycling technology, and more specifically, relates to a method for recycling waste lithium batteries that is integrated across the entire lithium battery supply chain. Background Technology

[0002] Lithium-ion batteries, as a green chemical power source, are widely used in consumer battery products, energy storage, and new energy electric vehicles due to their excellent charge and discharge performance. However, with the rapid upgrading of consumer electronics and the approaching end-of-life of new energy vehicle power batteries, the number of used lithium batteries is increasing dramatically year by year. The rational recycling and utilization of valuable metals from used lithium-ion batteries has become a research focus. Lithium-ion batteries consist of positive electrode materials, negative electrode materials, electrolyte solution, current collectors, and separators. Based on the different positive electrode materials, they can be divided into lithium cobalt oxide batteries, lithium iron phosphate batteries, and ternary lithium-ion batteries. Among them, ternary lithium-ion batteries, containing nickel and cobalt metals, have the highest recycling value.

[0003] The widely used technical route for recycling spent ternary lithium-ion batteries is pretreatment, wet leaching, impurity removal, and recycling and purification. Wet leaching is a crucial step in the recycling process. The main step involves leaching the pretreated spent lithium-ion battery powder, transferring valuable metals from the battery powder into the solution, thus providing conditions for subsequent impurity removal and purification. Currently, industrially, reductive leaching using inorganic acids and reducing agents is mainly employed. Commonly used inorganic acids include hydrochloric acid and sulfuric acid, while common reducing agents include hydrogen peroxide, sodium sulfite, and sodium thiosulfate. However, due to limitations in the pretreatment process, ternary battery powder contains varying amounts of copper and aluminum slag. When these slags into the leaching solution during wet leaching, they become copper and aluminum ions, often placing a significant burden on the subsequent impurity removal stage. This not only increases impurity removal costs but also carries away some nickel and cobalt ions during the precipitation process, significantly impacting the recovery rate of valuable metals like nickel and cobalt.

[0004] Currently, the main methods for removing copper and aluminum in recycling processes include:

[0005] (1) Removal of impurities after leaching: The leachate after leaching battery powder contains copper and aluminum ions. Excess iron powder is added to replace and remove copper from the leachate, and then Fe and Al ions are precipitated by adjusting the pH. Although the final nickel-cobalt solution obtained by this method is relatively pure, the precipitation process will remove a lot of valuable metal ions and lithium ions, and also introduce iron.

[0006] (2) Aluminum removal at the front end: The battery powder is dispersed in an alkaline sodium hydroxide solution. Utilizing the principle that alkali does not react with ternary cathode materials but can react with aluminum, aluminum is removed through alkali dissolution. Then, the powder particles of different densities are separated by cyclone separation. This method involves early alkali dissolution to remove aluminum, followed by physical separation using cyclone separation. However, this method suffers from incomplete separation, affecting downstream purification and recovery, resulting in a low recovery rate of valuable metals.

[0007] Therefore, current methods cannot efficiently and cost-effectively remove copper and aluminum, and the removal of copper and aluminum can easily introduce impurities, affecting the overall recovery rate of nickel and cobalt.

[0008] In view of this, this disclosure is hereby made. Summary of the Invention

[0009] The purpose of this disclosure is to provide a recycling method for waste lithium batteries that is integrated across the entire lithium battery supply chain, aiming to efficiently and cost-effectively remove copper and aluminum impurities while ensuring the recovery rate of valuable metals.

[0010] To achieve the above-mentioned objectives of this disclosure, the following technical solutions may be adopted:

[0011] The solution provided in this disclosure includes a recycling method for waste lithium batteries that is applied to the entire lithium battery chain. The method includes: subjecting waste lithium battery powder to alkaline leaching to obtain a first alkaline leaching residue and an aluminum-containing leachate; mixing the aluminum-containing leachate with glycine to perform a precipitation and solid-liquid separation to obtain aluminum hydroxide precipitate and aluminum-removed liquid.

[0012] The aluminum-removed liquid is mixed with glycine, inorganic alkali and copper salt to obtain an alkaline leaching solution. The alkaline leaching solution is then mixed with the first alkaline leaching residue and subjected to a second alkaline leaching in an oxygen-containing atmosphere.

[0013] In some embodiments of this disclosure, the aluminum-containing leachate is mixed with glycine to adjust the pH to 8.5-9.5 for a single precipitation and solid-liquid separation to obtain aluminum hydroxide precipitate and aluminum-removed liquid;

[0014] After aluminum removal, the liquid is mixed with glycine, then mixed with an inorganic base to adjust the pH to 10.5-11.5, and then mixed with copper salt.

[0015] In some embodiments of this disclosure, the concentration of glycine in the alkaline leaching solution is controlled to be 3 mol / L-5 mol / L during the preparation of the alkaline leaching solution.

[0016] In some embodiments of this disclosure, the copper salt is selected from at least one of copper sulfate and copper chloride.

[0017] In some embodiments of this disclosure, the mass ratio of the total amount of copper salt to glycine is (0.8-1.2):10.

[0018] In some embodiments of this disclosure, during the secondary alkaline leaching process, the alkaline leaching temperature is controlled to be 50°C-70°C.

[0019] In some embodiments of this disclosure, the alkali leaching time during the secondary alkali leaching process is 0.5h-2.0h.

[0020] In some embodiments of this disclosure, during the secondary alkali leaching process, the stirring rate is controlled to be 100 rpm-300 rpm.

[0021] In some embodiments of this disclosure, air is blown into the system during the secondary alkaline leaching process.

[0022] In some embodiments of this disclosure, after the second alkaline leaching is completed, solid-liquid separation is performed to obtain a second alkaline leaching residue and a copper-containing leachate.

[0023] In some embodiments of this disclosure, the waste lithium battery powder is ternary lithium-ion battery powder, and the obtained second alkaline leaching residue is subjected to reduction acid leaching to recover nickel, cobalt and manganese.

[0024] In some embodiments of this disclosure, the copper-containing leachate is mixed with a precipitant for secondary precipitation and solid-liquid separation to obtain a copper-containing precipitate and a post-precipitation liquid, and copper-containing precipitate is used to produce elemental copper.

[0025] In some embodiments of this disclosure, the precipitant is oxalic acid.

[0026] In some embodiments of this disclosure, the amount of precipitant is controlled so that the molar ratio of the precipitant to the copper ions in the copper-containing leaching solution is (1.0-1.1):1.

[0027] In some embodiments of this disclosure, the reaction temperature for secondary precipitation is 50°C-60°C, and the reaction time is 5 min-10 min.

[0028] In some embodiments of this disclosure, the process of producing elemental copper using copper-containing precipitate includes: washing the copper-containing precipitate and then calcining it under an inert atmosphere.

[0029] In some embodiments of this disclosure, the calcination temperature is controlled at 550℃-650℃ and the calcination time is 60min-120min.

[0030] In some embodiments of this disclosure, the copper plating solution and inorganic alkali are mixed to prepare an alkaline solution that meets the concentration requirements for a single alkaline leaching process, and then returned to the single alkaline leaching process.

[0031] In some embodiments of this disclosure, waste lithium battery powder is mixed with an inorganic alkaline solution for a single alkaline leaching and solid-liquid separation to obtain a first alkaline leaching residue and an aluminum-containing leachate.

[0032] In some embodiments of this disclosure, the inorganic alkali in the inorganic alkali solution is selected from at least one of sodium hydroxide and lithium hydroxide.

[0033] In some embodiments of this disclosure, the mass fraction of the inorganic alkaline solution is 0.8%-1.2%, and the liquid-to-solid ratio of the inorganic alkaline solution to the waste lithium battery powder is (4-6):1.

[0034] In some embodiments of this disclosure, the alkali leaching temperature for a single alkali leaching is 50°C-70°C.

[0035] In some embodiments of this disclosure, the alkali immersion time for a single alkali immersion is 0.3h-1.0h.

[0036] In some embodiments of this disclosure, the stirring rate is controlled to be 100 rpm-300 rpm during a single alkali leaching process.

[0037] In some embodiments of this disclosure, the particle size of the waste lithium battery powder is less than 0.106 mm.

[0038] Since valuable metals (such as nickel, cobalt, and manganese) in waste lithium-ion battery powder are insoluble in alkali, aluminum can be removed from the waste lithium-ion battery powder through a single alkaline leaching. The aluminum-containing leachate is then mixed with glycine to precipitate the aluminum, resulting in a dealuminized solution. This dealuminized solution is then mixed with glycine and copper salts. Utilizing the synergistic effect of glycine and copper ions, copper is selectively leached, achieving efficient removal of both copper and aluminum. The recycling method provided in this disclosure can efficiently and cost-effectively remove copper and aluminum, improving the recovery rate of valuable metals. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 A simplified process flow diagram of the recycling method provided in this disclosure;

[0041] Figure 2 A process flow diagram of the recycling method provided in this disclosure. Detailed Implementation

[0042] The embodiments of this disclosure will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of this disclosure. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0043] The endpoints and any values ​​of the ranges disclosed in this disclosure are not limited to the precise ranges or values, and such ranges or values ​​should be understood to include values ​​close to such ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed herein.

[0044] This disclosure provides a method for recycling waste lithium batteries that integrates the entire lithium battery supply chain. Since the positive electrode current collector of lithium batteries is typically aluminum foil and the negative electrode current collector is typically copper foil, the battery powder contains copper and aluminum impurities. For example... Figure 1 As shown, removing aluminum and copper through primary and secondary alkaline leaching significantly reduces the cost of subsequent leaching and impurity removal, and improves the recovery rate of valuable metals. Specifically, please refer to... Figure 1 and Figure 2 The recycling method includes the following steps:

[0045] S1, Alkali leaching to remove aluminum

[0046] Waste lithium battery powder undergoes a single alkaline leaching process to obtain a first alkaline leaching residue and an aluminum-containing leachate. The aluminum-containing leachate is then mixed with glycine to adjust the pH to 8.5-9.5 (e.g., 8.5, 9.0, 9.5, etc.) for a first precipitation. After sufficient precipitation, solid-liquid separation is performed to obtain aluminum hydroxide precipitate and a post-aluminum-removed liquid. Further pH control is used to ensure more complete aluminum deposition. The solid-liquid separation method is not limited; a filter press can be used to separate the alkaline-leached material. Since valuable metals (such as nickel, cobalt, and manganese) in waste lithium battery powder are insoluble in alkali, a single alkaline leaching process can remove aluminum (in the form of elemental aluminum or oxides) from the waste lithium battery powder. The specific reaction principle is as follows:

[0047] 2Al+2H2O+2NaOH=2NaAlO2+3H2↑;

[0048] Al₂O₃ + 2NaOH = 2NaAlO₂ + H₂O.

[0049] Specifically, the first step of the reaction involves elemental aluminum, yielding sodium aluminate and hydrogen gas; the second step involves aluminum oxide, yielding sodium aluminate and water.

[0050] In some embodiments of this disclosure, the primary alkaline leaching process includes: mixing waste lithium battery powder with an inorganic alkaline solution for primary alkaline leaching and separating the solid and liquid to obtain a first alkaline leaching residue and an aluminum-containing leachate. The inorganic alkaline in the inorganic alkaline solution is selected from at least one of sodium hydroxide and lithium hydroxide, and can be any one or more of the above, all of which can effectively leach aluminum.

[0051] To more effectively remove aluminum from waste lithium battery powder, the concentration and dosage of the inorganic alkaline solution were optimized. The mass fraction of the inorganic alkaline solution was 0.8%-1.2%, and the liquid-to-solid ratio of the inorganic alkaline solution to the waste lithium battery powder was (4-6):1. Specifically, the mass fraction of the inorganic alkaline solution could be 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, etc., and the mass ratio of the inorganic alkaline solution to the waste lithium battery powder could be 4:1, 5:1, 6:1, etc.

[0052] Furthermore, during the first alkaline leaching process, the leaching temperature is controlled at 50℃-70℃, the leaching time at 0.3h-1.0h, and the stirring speed at 100rpm-300rpm. By controlling the leaching temperature, time, and stirring speed, the reaction is ensured to proceed fully, allowing the aluminum to dissolve completely. Specifically, the leaching temperature can be 50℃, 60℃, 70℃, etc., the leaching time can be 0.3h, 0.5h, 0.8h, 1.0h, etc., and the stirring speed can be 100rpm, 200rpm, 300rpm, etc.

[0053] In some embodiments of this disclosure, the waste lithium battery powder can be ternary lithium-ion battery powder. Before the first alkaline leaching, the waste lithium battery powder is ground so that the particle size of the waste lithium battery powder is less than 0.106 mm, so as to make the reaction more complete.

[0054] S2, Alkaline leaching to remove copper

[0055] The aluminum-removed liquid is mixed with glycine, inorganic alkali, and copper salt to obtain an alkaline leaching solution. This solution is then mixed with the first alkaline leaching residue, and a second alkaline leaching is performed in an oxygen-containing atmosphere. During this process, the copper is selectively leached by the synergistic effect of glycine and copper ions. The specific reaction principle is as follows:

[0056] CuSO4+2HL+2NaOH→CuL2+Na2SO4+2H2O;

[0057] 2Cu 2+ +8L - +2Cu+O2+2H2O→4CuL2+4OH-.

[0058] In actual operation, the aluminum-removed liquid is mixed with glycine, and then mixed with inorganic alkali to adjust the pH value to 10.5-11.5 (such as 10.5, 11.0, 11.5, etc.). Then it is reacted with copper salt (such as the first step reaction), and after being mixed with the first alkali leaching residue, the second step reaction is carried out under an oxygen-containing atmosphere.

[0059] In some embodiments of this disclosure, the copper salt is selected from at least one of copper sulfate and copper chloride, and can be any one or more of them, all of which can provide copper ions to participate in the reaction. When preparing the alkaline leaching solution, the concentration of glycine in the alkaline leaching solution is controlled to be 3 mol / L-5 mol / L, and the mass ratio of copper salt to the total amount of glycine added is (0.8-1.2):10. By controlling the amount of glycine and copper salt, the copper is leached more thoroughly. Specifically, the concentration of glycine in the alkaline leaching solution can be 3 mol / L, 4 mol / L, 5 mol / L, etc.; the mass ratio of copper salt to the total amount of glycine added can be 0.8:10, 0.9:10, 1.0:10, 1.1:10, 1.2:10, etc.

[0060] In some embodiments of this disclosure, during the secondary alkaline leaching process, the leaching temperature is controlled at 50℃-70℃, the leaching time at 0.5h-2.0h, and the stirring speed at 100rpm-300rpm. By further controlling the temperature, time, and stirring speed of the secondary alkaline leaching, the copper is more fully leached out. Specifically, the temperature of the secondary alkaline leaching can be 50℃, 60℃, 70℃, etc., the leaching time can be 0.5h, 1.0h, 1.5h, 2.0h, etc., and the stirring speed can be 100rpm, 200rpm, 300rpm, etc.

[0061] The secondary alkaline leaching must be carried out in an oxygen-containing atmosphere. The type of gas introduced is not limited, and oxygen for the reaction can be provided by blowing air into the solution.

[0062] In some embodiments of this disclosure, after the secondary alkaline leaching is completed, solid-liquid separation can be performed to obtain a second alkaline leaching residue and a copper-containing leachate. The obtained second alkaline leaching residue is then subjected to a reduction acid leaching process to recover valuable metals such as nickel, cobalt, and manganese. The specific recovery process is not limited and can refer to existing technologies. Specifically, the solid-liquid separation method is not limited; a filter press can be used to filter the material after alkaline leaching, but it is not limited to this.

[0063] S3, Copper Recycling

[0064] The copper-containing leachate obtained from S2 undergoes post-treatment to recover elemental copper. In actual operation, the copper-containing leachate is mixed with a precipitant for secondary precipitation, followed by solid-liquid separation to obtain copper-containing precipitate and a post-precipitation liquid. Elemental copper is then produced using the copper-containing precipitate. The solid-liquid separation method is not limited; a filter press can be used to separate the copper-containing precipitate from the solution.

[0065] In some embodiments of this disclosure, the precipitant is oxalic acid. Taking oxalic acid as an example, under the action of copper-containing leaching solution and oxalic acid crystal copper precipitation, copper in battery powder can be selectively removed, which greatly saves the cost of subsequent leaching and impurity removal and improves the recovery rate of valuable metals.

[0066] Furthermore, by controlling the amount of precipitant, the molar ratio of precipitant to copper ions in the copper-containing leaching solution is (1.0-1.1):1, so that the precipitant is slightly in excess, so that the copper can be fully recovered.

[0067] Furthermore, the reaction temperature for secondary precipitation is 50℃-60℃, and the reaction time is 5min-10min. The reaction temperature and time are controlled to ensure that the reaction proceeds fully. Specifically, the reaction temperature for secondary precipitation can be 50℃, 55℃, 60℃, etc., and the reaction time can be 5min, 8min, 10min, etc.

[0068] In some embodiments of this disclosure, the process of producing elemental copper using copper-containing precipitate includes: washing the copper-containing precipitate, then calcining it under an inert atmosphere to decompose it and obtain elemental copper. The calcination temperature is controlled at 550℃-650℃, and the calcination time is controlled at 60min-120min. By controlling the calcination temperature and time, the reaction is made sufficient to recover elemental copper. Calcination under an inert atmosphere prevents oxygen from interfering with the reaction, and the calcination temperature and time are controlled to ensure the complete decomposition of the copper-containing precipitate to obtain elemental copper. Specifically, the copper-containing precipitate can be washed with pure water, and the inert atmosphere can be nitrogen; the calcination temperature can be 550℃, 600℃, 650℃, etc., and the calcination time can be 60min, 80min, 100min, 120min, etc.

[0069] In some embodiments of this disclosure, the copper plating solution and inorganic alkali are mixed to prepare an alkaline solution (mass fraction of 0.8%-1.2%) that meets the concentration requirements for a first alkaline leaching process, and the resulting alkaline solution is returned to the first alkaline leaching process.

[0070] It can be seen that the recycling method provided in this disclosure generates less wastewater, and the reaction solution can be recycled to prepare crude aluminum hydroxide and elemental copper products.

[0071] The features and performance of this disclosure will be further described in detail below with reference to embodiments.

[0072] It should be noted that the battery powders processed in the following examples and comparative examples were obtained by disassembling and crushing conventional nickel-cobalt-manganese lithium-ion batteries. The composition of the battery powders processed in each example is shown in Table 1.

[0073] Example 1

[0074] This embodiment provides a method for recycling waste lithium batteries that is applied to the entire lithium battery supply chain, including the following steps:

[0075] (1) 100g of battery powder was repeatedly crushed and ground until its particle size was less than 0.106mm to obtain fine-particle battery powder to be treated. 500mL of NaOH solution with pH=13.4 (i.e., 1% by mass) was prepared. The NaOH solution and the fine-particle battery powder to be treated were mixed evenly and heated to 60℃. The mixture was stirred continuously for 0.5h with a stirrer at a speed of 200rpm. After alkaline leaching, the residue after alkaline leaching was separated by a filter press to obtain alkaline leaching residue 1 and aluminum-containing leachate. The pH of the aluminum-containing leachate was adjusted to 9 with glycine solution (about 50g was added). After sufficient precipitation, it was filtered to obtain aluminum hydroxide precipitate. 100g of glycine (about 4mol / L in the solution) was added to the aluminum-removed liquid, and NaOH was added to adjust the pH to 11. Finally, 15g of copper sulfate was added to prepare alkaline leaching solution 2.

[0076] (2) Mix the prepared alkaline leaching solution 2 with the alkaline leaching residue 1 obtained above, heat to 60°C, and stir continuously for 1 hour using a stirrer at a speed of 200 rpm. During the process, blow air into the solution at a flow rate of 1 L·min. -1 After alkaline leaching, the leaching residue is filtered and separated to obtain alkaline leaching residue 2 and copper-containing leachate. The alkaline leaching residue is then fed into the subsequent reduction acid leaching recovery process to further recover and utilize valuable metals such as nickel, cobalt, and lithium.

[0077] (3) Add oxalic acid crystals to the copper-containing leaching solution. The amount of oxalic acid added is 1:1 molar ratio of copper ions. Heat and stir at 55°C for 10 min. Then filter to separate the blue precipitate copper oxalate from the solution. After washing the copper oxalate precipitate with pure water, it can be calcined under inert gas protection to decompose it into elemental copper. The calcination temperature is 600°C and the calcination time is 60 min. After the copper ions are precipitated, add sodium hydroxide to prepare an alkaline leaching solution 1 with pH = 13.4 for recycling in step (1).

[0078] Example 2-3

[0079] The only difference from Example 1 is that the composition of the battery powder is different. The specific composition and the copper and aluminum removal effects of Examples 1-3 are shown in Table 1.

[0080] Table 1. Test results of copper and aluminum removal effect

[0081]

[0082] Note: Oxygen and carbon content are not shown because they are not recovered in the current process.

[0083] It can be seen that after processing with the method of this embodiment, copper and aluminum in the battery powder are effectively removed, and valuable metals such as nickel, cobalt and manganese in the battery powder are not carried out.

[0084] Example 4

[0085] 100g of battery powder from Example 1 was processed. The single-batch operation steps were the same as in Example 1, and the cycle was repeated 10 times, processing a total of 1000g of battery powder. The copper and aluminum removal effect of the 10th cycle is shown in Table 2.

[0086] Table 2 Test results of copper and aluminum removal effect

[0087]

[0088] It is evident that the method disclosed herein can effectively remove copper and aluminum impurities even after 10 cycles, without affecting the content of valuable metals such as nickel, cobalt, and manganese.

[0089] Examples 5-7

[0090] 100g of battery powder from Example 1 was processed, and the operation steps were the same as in Example 1, except that 50g, 75g, and 125g of glycine were added to the aluminum removal solution after aluminum removal. The copper and aluminum removal effects are shown in Table 3 below.

[0091] Table 3 Test results of copper and aluminum removal effect

[0092] Serial Number materials glycine addition amount Cu% Al％ sample Ternary battery powder before processing / 2.95 1.81 Example 5 Processed ternary lithium battery powder 50g 1.71 0.23 Example 6 Processed ternary lithium battery powder 75g 0.23 0.27 Example 1 Processed ternary lithium battery powder 100g 0.02 0.3 Example 7 Processed ternary lithium battery powder 125g 0.3 0.28

[0093] It is evident that as the glycine concentration further increases, the glycine ion activity decreases, while the solution viscosity increases. This reduces the rate at which glycine ions diffuse to the copper surface and the rate at which copper ions leave the copper surface and enter the bulk solution, resulting in a decrease in the copper leaching rate.

[0094] Example 8

[0095] This embodiment provides a method for recycling waste lithium batteries that is applied to the entire lithium battery supply chain, including the following steps:

[0096] (1) 100g of battery powder was repeatedly crushed and ground until its particle size was less than 0.106mm to obtain fine-particle battery powder to be treated. 400mL of 0.8% NaOH solution was prepared, and the NaOH solution and the fine-particle battery powder to be treated were mixed evenly. The mixture was heated to 50℃ and stirred continuously for 1.0h with a stirrer at a speed of 100rpm. After alkaline leaching, the residue after alkaline leaching was separated by a filter press to obtain alkaline leaching residue 1 and aluminum-containing leachate. The pH of the aluminum-containing leachate was adjusted to 8.5 with glycine solution. After sufficient precipitation, it was filtered to obtain aluminum hydroxide precipitate. Glycine was added to the aluminum-removed liquid to make the concentration of glycine in the solution 3mol / L, and NaOH was added to adjust the pH to 10.5. Finally, copper sulfate was added (so that the mass ratio of copper salt to total glycine added was 0.8:10) to prepare alkaline leaching solution 2.

[0097] (2) Mix the prepared alkaline leaching solution 2 with the alkaline leaching residue 1 obtained above, heat to 50°C, and stir continuously for 2.0 h with a stirrer at a speed of 100 rpm. During the process, blow air into the solution at a flow rate of 1 L·min. -1 After alkaline leaching, the leaching residue is filtered and separated to obtain alkaline leaching residue 2 and copper-containing leachate. The alkaline leaching residue is then fed into the subsequent reduction acid leaching recovery process to further recover valuable metals such as nickel, cobalt, and lithium.

[0098] (3) Add oxalic acid crystals to the copper-containing leaching solution. The amount of oxalic acid added is 1:1 molar ratio of copper ions to oxalic acid. Heat and stir at 50°C for 10 min. Then filter to separate the blue precipitate copper oxalate from the solution. After washing the copper oxalate precipitate with pure water, it can be calcined under inert gas protection to decompose it into elemental copper. The calcination temperature is 550°C and the calcination time is 120 min. After the copper ions are precipitated, add sodium hydroxide to prepare an alkaline leaching solution with a mass fraction of 0.8% for recycling in step (1). The copper and aluminum removal effect is shown in Table 4:

[0099] Table 4 Test results of copper and aluminum removal effect

[0100]

[0101] Example 9

[0102] This embodiment provides a method for recycling waste lithium batteries that is applied to the entire lithium battery supply chain, including the following steps:

[0103] (1) 100g of battery powder was repeatedly crushed and ground until its particle size was less than 0.106mm to obtain fine-particle battery powder to be treated. 600mL of 1.2% NaOH solution was prepared, and the NaOH solution and the fine-particle battery powder to be treated were mixed evenly. The mixture was heated to 70℃ and stirred continuously for 0.3h with a stirrer at a speed of 300rpm. After alkaline leaching, the residue after alkaline leaching was separated by a filter press to obtain alkaline leaching residue 1 and aluminum-containing leachate. The pH of the aluminum-containing leachate was adjusted to 9.5 with glycine solution. After sufficient precipitation, it was filtered to obtain aluminum hydroxide precipitate. Glycine was added to the aluminum-removed liquid to make the concentration of glycine in the solution 5mol / L, and NaOH was added to adjust the pH to 11.5. Finally, copper sulfate was added (so that the mass ratio of copper salt to total glycine added was 1.2:10) to prepare alkaline leaching solution 2.

[0104] (2) Mix the prepared alkaline leaching solution 2 with the alkaline leaching residue 1 obtained above, heat to 70°C, and stir continuously for 0.5 hours using a stirrer at a speed of 300 rpm. During the process, blow air into the solution at a flow rate of 1 L·min. -1 After alkaline leaching, the leaching residue is filtered and separated to obtain alkaline leaching residue 2 and copper-containing leachate. The alkaline leaching residue is then fed into the subsequent reduction acid leaching recovery process to further recover valuable metals such as nickel, cobalt, and lithium.

[0105] (3) Add oxalic acid crystals to the copper-containing leaching solution. The amount of oxalic acid added is 1.1:1 molar ratio of copper ions to oxalic acid. Heat and stir at 60°C for 5 minutes. Then filter to separate the blue precipitate copper oxalate from the solution. After washing the copper oxalate precipitate with pure water, it can be calcined under inert gas protection to decompose it into elemental copper. The calcination temperature is 650°C and the calcination time is 60 minutes. After the copper ions are precipitated, add sodium hydroxide to prepare an alkaline leaching solution with a mass fraction of 1.2% for recycling in step (1). The copper and aluminum removal effect is shown in Table 5.

[0106] Table 5 Test results of copper and aluminum removal effect

[0107]

[0108] It should be noted that the above are only representative embodiments provided by this disclosure. The effects claimed by this disclosure can be achieved by using the raw materials and parameter ranges defined by this disclosure. Specific embodiments are not all listed here.

[0109] Comparative Example 1

[0110] 100g of battery powder (with the same composition as in Example 1) was repeatedly crushed and ground until its particle size was less than 0.106mm to obtain fine-particle-size battery powder to be treated. 500mL of NaOH solution with a pH of 13.4 was prepared, and the NaOH solution and the fine-particle-size battery powder to be treated were mixed evenly. The mixture was heated to 60°C and continuously stirred for 0.5h using a stirrer at a speed of 200rpm.

[0111] After alkaline leaching, the leached residue is separated by a filter press to obtain alkaline leaching residue. The specific copper and aluminum removal effects are shown in Table 6.

[0112] Table 6. Test results of copper and aluminum removal effect in Comparative Example 1.

[0113]

[0114] It is evident that Comparative Example 1 can only remove aluminum from the battery powder.

[0115] Comparative Example 2

[0116] 100g of battery powder (with the same composition as in Example 1) was repeatedly crushed and ground until its particle size was less than 0.106mm to obtain fine-particle-size battery powder to be treated. A 500mL NaOH solution with a pH of 13.4 was prepared. The NaOH solution and the fine-particle-size battery powder to be treated were mixed evenly, and 150g of glycine was added. The mixture was heated to 60°C and continuously stirred for 0.5h at a speed of 200rpm.

[0117] After alkaline leaching, the leached residue is separated by a filter press to obtain alkaline leaching residue. The specific copper and aluminum removal effects are shown in Table 7.

[0118] Table 7. Test results of copper and aluminum removal effect in Comparative Example 2.

[0119]

[0120] It is evident that Comparative Example 2 can remove copper and aluminum impurities to some extent, but the removal effect is not ideal.

[0121] Comparative Example 3

[0122] 100g of battery powder from Example 1 was processed, and the operation steps were the same as in Example 1, except that glycine was replaced with an equal amount of ethylenediaminetetraacetic acid (EDTA). The copper and aluminum removal effect is shown in Table 8.

[0123] Table 8. Test results of copper and aluminum removal effect in Comparative Example 3.

[0124]

[0125] It is evident that Comparative Example 3 is not effective in removing copper impurities.

[0126] Comparative Example 4

[0127] 100g of battery powder from Example 1 was processed. The operation steps were the same as in Example 1, except that NaOH was added to adjust the pH to 11, and copper sulfate was not added. Alkali leaching solution 2 was prepared. The copper and aluminum removal effect is shown in Table 9.

[0128] Table 9. Test results of copper and aluminum removal effect in Comparative Example 4.

[0129]

[0130] It is evident that Comparative Example 4 is not effective in removing copper impurities.

[0131] Industrial applicability

[0132] This disclosure describes a method for removing aluminum from waste lithium battery powder using a single alkaline leaching process. The aluminum-containing leachate is mixed with glycine, and the synergistic effect of glycine and copper ions selectively leaches copper and aluminum. The method is simple, easy to implement, and low-cost. It efficiently removes copper and aluminum without affecting the recovery rate of valuable metals, and has excellent prospects for industrial application.

Claims

1. A method for recycling waste lithium batteries applied to the entire lithium battery supply chain, characterized in that, include: Waste lithium battery powder is subjected to a first alkaline leaching to obtain a first alkaline leaching residue and an aluminum-containing leachate. The aluminum-containing leachate is mixed with glycine to adjust the pH value to 8.5-9.5 for a first precipitation and solid-liquid separation to obtain aluminum hydroxide precipitate and aluminum-removed liquid. The waste lithium battery powder is ternary lithium-ion battery powder. The aluminum-removed liquid is mixed with glycine, then mixed with an inorganic alkali to adjust the pH to 10.5-11.5, and then mixed with copper salt to obtain an alkaline leaching solution. The alkaline leaching solution is then mixed with the first alkaline leaching residue and subjected to a second alkaline leaching in an oxygen-containing atmosphere.

2. The recycling method according to claim 1, characterized in that, When preparing the alkaline leaching solution, the concentration of glycine in the alkaline leaching solution is controlled to be 3 mol / L-5 mol / L.

3. The recycling method according to claim 1 or 2, characterized in that, The copper salt is selected from at least one of copper sulfate and copper chloride.

4. The recycling method according to claim 3, characterized in that, The mass ratio of the total amount of copper salt to glycine added is (0.8-1.2):

10.

5. The recycling method according to claim 1, characterized in that, During the secondary alkaline leaching process, the alkaline leaching temperature is controlled at 50℃-70℃.

6. The recycling method according to claim 1, characterized in that, During the secondary alkaline leaching process, the leaching time is 0.5h-2.0h.

7. The recycling method according to claim 1, characterized in that, During the secondary alkali leaching process, the stirring speed is controlled at 100rpm-300rpm.

8. The recycling method according to claim 1, characterized in that, During the secondary alkaline leaching process, air is blown into the system.

9. The recycling method according to claim 1, characterized in that, After the second alkaline leaching is completed, solid-liquid separation is performed to obtain a second alkaline leaching residue and a copper-containing leachate.

10. The recycling method according to claim 9, characterized in that, The obtained second alkaline leaching residue is subjected to reducing acid leaching to recover nickel, cobalt, and manganese.

11. The recycling method according to claim 9, characterized in that, The copper-containing leachate is mixed with a precipitant for secondary precipitation and solid-liquid separation to obtain a copper-containing precipitate and a copper-containing liquid after precipitation. The copper-containing precipitate is then used to produce elemental copper.

12. The recycling method according to claim 11, characterized in that, The precipitant is oxalic acid.

13. The recycling method according to claim 12, characterized in that, By controlling the amount of the precipitant, the molar ratio of the precipitant to the copper ions in the copper-containing leachate is (1.0-1.1):

1.

14. The recycling method according to claim 11, characterized in that, The secondary precipitation reaction temperature is 50℃-60℃, and the reaction time is 5min-10min.

15. The recycling method according to claim 11, characterized in that, The process of producing elemental copper using the copper-containing precipitate includes: washing the copper-containing precipitate and then calcining it under an inert atmosphere.

16. The recycling method according to claim 15, characterized in that, The roasting temperature is controlled at 550℃-650℃, and the roasting time is 60min-120min.

17. The recycling method according to claim 11, characterized in that, The copper plating solution and inorganic alkali are mixed to prepare an alkaline solution that meets the concentration requirements of the first alkaline leaching process, and then returned to the first alkaline leaching process.

18. The recycling method according to claim 1, characterized in that, The waste lithium battery powder is mixed with an inorganic alkaline solution for a single alkaline leaching and solid-liquid separation to obtain the first alkaline leaching residue and the aluminum-containing leachate.

19. The recycling method according to claim 18, characterized in that, The inorganic base in the inorganic alkaline solution is selected from at least one of sodium hydroxide and lithium hydroxide.

20. The recycling method according to claim 18, characterized in that, The inorganic alkaline solution has a mass fraction of 0.8%-1.2%, and the liquid-to-solid ratio of the inorganic alkaline solution to the waste lithium battery powder is (4-6):

1.

21. The recycling method according to claim 18, characterized in that, The alkali leaching temperature for the first alkali leaching is 50℃-70℃.

22. The recycling method according to claim 18, characterized in that, The alkali leaching time for the first alkali leaching is 0.3h-1.0h.

23. The recycling method according to claim 18, characterized in that, During the first alkaline leaching process, the stirring speed is controlled at 100rpm-300rpm.

24. The recycling method according to claim 1, characterized in that, The particle size of the waste lithium battery powder is less than 0.106 mm.

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