Recycling and processing methods based on lithium battery powder

Abstract

A recycling method based on lithium-ion battery powder includes the following steps: pulping the lithium-ion battery powder to obtain a slurry; mixing sulfuric acid, a reducing agent, and the slurry, followed by a first-stage leaching and filtration operation to obtain a first leachate and a first leaching residue; subjecting the first leachate to P2O4 extraction to remove impurities, obtaining a battery-grade nickel-cobalt-manganese solution; mixing the sulfuric acid, the reducing agent, and the first leaching residue, followed by a second-stage leaching and filtration operation to obtain a second leachate and a second leaching residue; subjecting the second leachate to impurity removal filtration to obtain a filtrate and a filter residue; and subjecting the second leaching residue to high-acid leaching and filtration to obtain battery-grade graphite raw material; wherein the pH value in the first-stage leaching and filtration operation is 4-6; and the pH value in the second-stage leaching and filtration operation is 1-2.

Description

Technical Field

[0001] This application relates to a recycling method based on lithium battery powder. Background Technology

[0002] The new energy industry is developing rapidly, and the supporting waste battery recycling industry is growing larger and larger. However, there are still technical bottlenecks in how to recycle efficiently and in a green manner.

[0003] Currently, there are two processes for producing battery-grade nickel-cobalt-manganese from lithium-ion battery powder: pyrometallurgical and hydrometallurgical processes. The pyrometallurgical process employs a priority lithium extraction-drying-smelting-ball milling-leaching-purification process. This process is energy-intensive and highly polluting. Its advantage is that after pyrometallurgical impurity removal, only impurity extraction is needed during purification to produce battery-grade nickel-cobalt-manganese solution, saving significant acid and alkali consumption and reducing costs. However, to comply with the concept of green recycling, the production of battery-grade nickel-cobalt-manganese from lithium-ion battery powder generally adopts the hydrometallurgical process. The hydrometallurgical process typically uses leaching-impurity removal-extraction-lithium extraction to process the battery powder. Impurity removal of battery powder often involves adjusting the solution pH with soda ash / calcium carbonate to remove iron and aluminum from the solution. To achieve better impurity removal, the amount of residual acid introduced into the solution during the impurity removal process increases, leading to increased consumption of auxiliary materials. In the extraction process, to ensure the leached nickel-cobalt-manganese solution meets battery-grade standards, P507 extraction is commonly used. P507 extraction requires extracting all nickel and cobalt from the leachate into the organic phase, followed by back-extraction with sulfuric acid or hydrochloric acid. The amount of nickel and cobalt ions required in this back-extraction process is equivalent to twice the amount of hydrogen ions. The resulting organic phase is then saponified with liquid alkali, leading to excessive consumption of sulfuric acid and liquid alkali as auxiliary materials. Furthermore, the complete extraction process complicates the entire recycling process. Simultaneously, current methods for recycling waste lithium-ion battery powder generally treat the leaching residue as solid waste or hazardous waste. However, the leaching residue contains a large amount of graphite, resulting in a waste of graphite resources.

[0004] Therefore, there is an urgent need for a battery powder recycling method that simplifies the process, consumes fewer auxiliary materials, has a good impurity removal effect, and can prepare battery-grade nickel-cobalt-manganese solutions and battery-grade graphite raw materials. Summary of the Invention

[0005] Therefore, it is necessary to provide a recycling method based on lithium battery powder that features simplified process, low auxiliary material consumption, good impurity removal effect, and the ability to prepare battery-grade nickel-cobalt-manganese solution and battery-grade graphite raw materials.

[0006] A recycling method based on lithium battery powder includes the following steps:

[0007] The lithium-extracted battery powder is slurried to obtain a slurry.

[0008] After mixing sulfuric acid, reducing agent and the slurry, the first stage of leaching and filtration is carried out to obtain the first leachate and the first leaching residue.

[0009] The first leachate was subjected to P204 extraction to remove impurities, resulting in a battery-grade nickel-cobalt-manganese solution.

[0010] The sulfuric acid, the reducing agent, and the first leaching residue are mixed and then subjected to a second-stage leaching and filtration operation to obtain a second leaching solution and a second leaching residue.

[0011] The second leachate is subjected to a filtration process to remove impurities, resulting in a filtrate and a filter residue.

[0012] The second leaching residue was subjected to a high-acid leaching and filtration operation to obtain battery-grade graphite raw material;

[0013] The pH value in the first leaching and filtration operation is 4-6;

[0014] The pH value in the second leaching and filtration operation is 1-2.

[0015] Details of one or more embodiments of this application are set forth in the following drawings and description. Other features, objects, and advantages of this application will become apparent from the specification, drawings, and claims. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic flowchart of a lithium battery powder recycling method in one embodiment;

[0018] Figure 2 This is a process flow diagram of a recycling method based on lithium battery powder. Detailed Implementation

[0019] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0020] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] Please see Figure 1 One embodiment of the recycling and processing method based on lithium battery powder includes some or all of the following steps:

[0023] S100 is used to slurry the lithium-extracted battery powder to obtain a slurry.

[0024] In this embodiment, the lithium extraction residue after lithium extraction is lithium-ion battery powder. The battery powder is then pulped to obtain a slurry, which facilitates subsequent recycling and processing.

[0025] S200, sulfuric acid, reducing agent and slurry are mixed and then subjected to the first stage of leaching and filtration to obtain the first leachate and the first leaching residue.

[0026] In this embodiment, the battery powder after lithium extraction mainly contains metallic elements such as iron, aluminum, copper, nickel, cobalt, and manganese. A first-stage leaching and filtration operation is performed in a leaching tank after mixing sulfuric acid, a reducing agent, and a slurry. The pH value of this first-stage leaching and filtration operation is controlled between 4 and 6. At a pH between 4 and 6, and under the influence of the reducing agent, metallic elements such as iron, aluminum, and copper easily precipitate. This allows for the separation of nickel, cobalt, and manganese from iron, aluminum, and copper, facilitating the recovery of these metallic elements.

[0027] S300, the first leachate is subjected to P204 extraction to remove impurities, resulting in a battery-grade nickel-cobalt-manganese solution.

[0028] In this embodiment, since the lithium-extracted battery powder is doped with calcium, and the calcium is incorporated into the first leachate after the first leaching and filtration operation, the calcium ions in the first leachate are extracted by adding P204 extractant, based on the characteristic of P204 extractant being effective in extracting calcium ions. This process removes impurities from the first leachate to obtain a battery-grade nickel-cobalt-manganese solution. Therefore, a full extraction process for the leachate is unnecessary, effectively reducing the consumption of auxiliary materials and greatly simplifying the preparation method of the battery-grade nickel-cobalt-manganese solution, thereby simplifying the recycling and processing steps of the lithium-extracted battery powder.

[0029] Furthermore, by designing a process that involves first extracting lithium from battery powder and then recycling it, the preparation process of battery-grade nickel-cobalt-manganese solution can be further simplified by eliminating the need for additional lithium ion extraction.

[0030] It should also be noted that a nickel + cobalt + manganese content of 100g / L to 120g / L constitutes a battery-grade nickel-cobalt-manganese solution.

[0031] S400, the sulfuric acid, the reducing agent and the first leaching residue are mixed and then subjected to a second leaching and filtration operation to obtain a second leaching solution and a second leaching residue.

[0032] In this embodiment, sulfuric acid, reducing agent and first leaching residue are mixed and then subjected to second-stage leaching filtration in a two-stage leaching tank. The pH value of the second-stage leaching filtration is controlled at 1 to 2. Under the action of the reducing agent and at a pH value of 1 to 2, a second leaching residue is formed. Iron, aluminum and copper elements in the first leaching residue are leached out to form the second leachate, thus enabling the recovery of iron, aluminum and copper elements.

[0033] S500, the second leachate is subjected to a filtration operation to remove impurities, resulting in a filtrate and a filter residue.

[0034] In this embodiment, the second leachate is filtered to remove impurities, and the filter residue is iron, aluminum and copper slag, thus achieving the recovery of iron, aluminum and copper elements.

[0035] S600, the second leaching residue is subjected to high acid leaching and filtration to obtain battery-grade graphite raw material.

[0036] In this embodiment, since the second leaching residue is rich in graphite, battery-grade graphite raw material can be obtained by performing a high-acid leaching and filtration operation on the second leaching residue, thereby realizing the recycling and reuse of graphite and saving the cost of disposing of the second leaching residue as solid waste or hazardous waste.

[0037] It should be noted that battery-grade graphite raw materials only need to undergo graphitization once to obtain battery-grade graphite. Battery-grade graphite raw materials can only be obtained when the content of nickel, cobalt and manganese in the leaching residue is less than 0.08%, and no secondary impurity removal is required.

[0038] It should also be noted that high acidity here refers to acid with an acidity of 100g / L or higher, while the acidity of the first-stage filtration and second-stage filtration operations is both below 100g / L.

[0039] The pH value in the first leaching and filtration operation is 4-6; the pH value in the second leaching and filtration operation is 1-2.

[0040] The aforementioned lithium-ion battery powder recycling method involves mixing sulfuric acid, a reducing agent, and a slurry, followed by a first-stage leaching and filtration operation. The pH value is strictly controlled between 4 and 6, and under the action of the reducing agent, iron, aluminum, and copper elements in the lithium-ion battery powder precipitate, forming the first leaching residue. Filtration separates the first leaching residue from the first leachate. The first leachate is then subjected to P204 extraction to remove impurities, specifically by using P204 extractant to remove calcium ions, thus preparing a battery-grade nickel-cobalt-manganese solution. Therefore, a full extraction process is unnecessary to prepare this solution, effectively reducing auxiliary material consumption and simplifying the preparation method. This simplifies the lithium-ion battery powder recycling process, thereby improving recycling efficiency and reducing costs.

[0041] Furthermore, sulfuric acid, reducing agent, and the first leaching residue are mixed and subjected to a second-stage leaching and filtration operation. Simultaneously, the pH value is strictly controlled between 1 and 2, and a second leaching residue is formed under the action of the reducing agent. This process also leaches out iron, aluminum, and copper elements from the first leaching residue, forming a second leachate. Filtration separates the second leaching residue and the second leachate. The second leachate is then filtered to remove impurities, yielding a filter residue, which is a mixed precipitate of iron, aluminum, and copper, achieving a good impurity removal and recovery effect. Furthermore, since the second leaching residue is rich in graphite, high-acid leaching and filtration can be performed on it to obtain battery-grade graphite raw materials, enabling graphite recycling and reuse, while saving the cost of disposing of the second leaching residue as solid waste or hazardous waste.

[0042] In one embodiment, the specific steps for slurry preparation of lithium-ion battery powder are as follows: pure water is added to the lithium-ion battery powder for slurry preparation, resulting in a slurry with a solid content of 20% to 30%. It should be noted that using pure water to slurry the lithium-ion battery powder ensures a slurry with a solid content of 20% to 30%.

[0043] In one embodiment, after performing P204 extraction to remove impurities from the first leachate to obtain a battery-grade nickel-cobalt-manganese solution, and before performing a second-stage leaching and filtration operation after mixing the sulfuric acid, the reducing agent, and the first leaching residue to obtain a second leachate and a second leaching residue, the recycling method further includes the following step: dissolving the first leaching residue. It should be noted that the first leaching residue obtained after filtration needs to be in liquid form first. Pure water is added to dissolve the first leaching residue to facilitate the subsequent second-stage leaching and filtration operation.

[0044] In one embodiment, after the step of dissolving the first leaching residue and before the step of performing P204 extraction to remove impurities from the first leaching solution to obtain a battery-grade nickel-cobalt-manganese solution, the recycling method further includes the following steps:

[0045] The content of the first leaching residue after dissolution was tested.

[0046] The content of the first leaching residue is determined, and the specific determination operation is as follows:

[0047] When the mass percentage of iron and aluminum in the first leaching residue is greater than or equal to 5%, the sulfuric acid, the reducing agent and the first leaching residue are mixed and then subjected to a second stage of leaching and filtration.

[0048] When the mass percentage of iron and aluminum in the first leaching residue is less than 5%, the sulfuric acid, the reducing agent, the first leaching residue and the slurry are mixed and then subjected to the first stage of leaching and filtration.

[0049] It should be noted that by testing the iron and aluminum content of the first leaching residue, the impurity content in the first leaching residue can be obtained. When the mass percentage of the impurity content is less than 5%, the first leaching residue is returned to the first leaching tank and circulated for the first stage of leaching and filtration. This can effectively increase the impurity content in the second leaching solution, facilitate impurity removal, and reduce the waste of auxiliary materials from multiple impurity removal processes. This effectively reduces the amount of auxiliary materials used for impurity removal, and thus effectively reduces the recycling and processing costs of lithium battery powder.

[0050] In one embodiment, the specific steps for performing P204 extraction to remove impurities from the first leachate to obtain a battery-grade nickel-cobalt-manganese solution are as follows:

[0051] After adding P204 extractant to the first leachate, an extraction operation was performed to obtain the battery-grade nickel-cobalt-manganese solution.

[0052] It should be noted that by extracting other impurity ions in the first leachate into the P204 extractant, a better impurity removal effect can be achieved, and battery-grade nickel-cobalt-manganese solution can also be prepared.

[0053] In one embodiment, the specific steps for performing impurity removal filtration on the second leachate are as follows:

[0054] Active metals are added to the second leachate to remove copper.

[0055] Alkaline salts were added to the second leaching solution after copper removal and the solution was filtered to obtain filter residue and filtrate.

[0056] It should be noted that by adding an active metal to the second leachate for copper removal through displacement, copper ions in the second leachate can be removed. Then, by adding an alkaline salt, the pH of the second leachate is adjusted to between 3 and 4, at which point both iron and aluminum can form corresponding metal salt precipitates. Filtration then yields filter residue and filtrate, with the filter residue being iron-aluminum-copper slag. This effectively recovers iron, aluminum, and copper metal elements.

[0057] In one embodiment, the active metal is one of iron powder, manganese powder, or nickel powder. It should be noted that, according to the metal activity series, selecting an active metal with a higher activity than copper will displace copper ions from the second leaching solution.

[0058] In one embodiment, the alkaline salt is industrial-grade sodium carbonate or industrial-grade sodium hydroxide. It should be noted that using high-purity raw materials such as industrial-grade sodium carbonate and industrial-grade sodium hydroxide as alkaline salts can effectively reduce the introduction of impurities, thereby reducing the use of impurity removal auxiliary materials and effectively reducing the recycling and processing costs of lithium battery powder.

[0059] In one embodiment, the specific steps for performing a high-acid leaching and filtration operation on the second leaching residue to obtain battery-grade graphite raw material are as follows:

[0060] The sulfuric acid, the reducing agent, and the second leaching residue are mixed and then subjected to a first high-acid leaching and filtration operation to obtain a first high-acid leaching residue and a first high-acid leaching solution.

[0061] The sulfuric acid, the reducing agent, and the first high-acid leaching residue are mixed and then subjected to a second high-acid leaching and filtration operation to obtain the battery-grade graphite raw material.

[0062] It should be noted that the metal content in the second leaching residue after the first and second leaching filtration operations is relatively low. To meet the leaching requirements of battery-grade graphite raw materials, the metal in the second leaching residue is first leached using a high-acid leaching filtration operation with an acidity greater than 100 g / L. This involves increasing the acidity of the sulfuric acid to increase the number of collisions between the sulfuric acid and the metal to be leached in the second leaching residue, allowing the metal to be leached in the second leaching residue to dissolve in the sulfuric acid. This effectively reduces the metal content in the first high-acid leaching residue. Secondly, the metal content in the first high-acid leaching residue after the first high-acid leaching and filtration operation is less than that in the second leaching residue. By setting the acidity of the second high-acid leaching and filtration operation to be greater than that of the first high-acid leaching and filtration operation, that is, by further increasing the acidity of sulfuric acid, the number of collisions between sulfuric acid and the metal to be leached in the first high-acid leaching residue is further increased, so that the metal to be leached in the first high-acid leaching residue can be dissolved in sulfuric acid, thereby enabling the second high-acid leaching residue to meet the standards of battery-grade graphite raw materials.

[0063] In one embodiment, after mixing the sulfuric acid, the reducing agent, and the second leaching residue and performing a first high-acid leaching and filtration operation to obtain a first high-acid leaching residue and a first high-acid leaching solution, the recycling method further includes the following step: mixing the sulfuric acid, the reducing agent, the first high-acid leaching solution, and the first leaching residue and performing a second-stage leaching and filtration operation. It should be noted that by returning the first high-acid leaching solution to the second-stage leaching tank, the amount of sulfuric acid added in the second-stage leaching and filtration operation can be reduced, enabling the recycling and reuse of auxiliary materials. This effectively reduces the consumption of auxiliary materials and consequently reduces the recycling and processing costs of lithium battery powder.

[0064] In one embodiment, after mixing the sulfuric acid, the reducing agent, and the first high-acid leaching residue and performing a second high-acid leaching and filtration operation to obtain the battery-grade graphite raw material, the recycling method further includes the following step: mixing the sulfuric acid, the reducing agent, the second high-acid leaching solution, and the second leaching residue and performing a first high-acid leaching and filtration operation. It should be noted that by returning the second high-acid leaching solution to the first high-acid leaching tank, the amount of sulfuric acid added in the first high-acid leaching and filtration operation can be reduced, enabling the recycling and reuse of auxiliary materials. This effectively reduces the consumption of auxiliary materials and consequently reduces the recycling and processing costs of lithium battery powder.

[0065] In one embodiment, the acidity of the first high-acid leaching filtration operation is 200 g / L to 300 g / L. It is understood that at an acidity of 200 g / L to 300 g / L, the number of collisions between the sulfuric acid and the metal to be leached in the second leaching residue can be increased, allowing the metal to be leached to dissolve in the sulfuric acid, thus leaching the metal in the second leaching residue into the first high-acid leaching solution.

[0066] In one embodiment, the acidity of the second high-acid leaching filtration operation is 300 g / L to 500 g / L. It is understood that at an acidity of 300 g / L to 500 g / L, the number of collisions between the sulfuric acid and the metal to be leached in the first high-acid leaching residue can be further increased, further dissolving the metal in the sulfuric acid. This allows the second high-acid leaching residue to meet the standards for battery-grade graphite raw materials, saving the cost of disposing of the leaching residue as hazardous or solid waste, and also enabling the recycling of graphite.

[0067] In one embodiment, the temperature for both the first and second high-acid leaching and filtration operations is 80°C to 100°C. It is understood that at temperatures between 80°C and 100°C, both operations can maximize the leaching of metal from the leaching residue, thereby achieving a better impurity removal effect.

[0068] In one embodiment, the temperature of the first leaching and filtration operation is 80℃~100℃. It should be noted that at a temperature of 80℃~100℃ and with the pH strictly controlled between 4 and 6, the content of impurities such as iron, aluminum, and copper in the first leachate is less than 2ppm. That is, when the impurity content is less than 2ppm, the first leachate does not need further impurity removal to meet the requirements of P204 extraction. The first leachate is then extracted and impurity removed using P204 extractant, thus obtaining a battery-grade nickel-cobalt-manganese solution. Therefore, a battery-grade nickel-cobalt-manganese solution can be prepared without a full extraction process, greatly simplifying the preparation process and thus simplifying the recycling steps of lithium battery powder, further improving the recycling efficiency of lithium battery powder.

[0069] In one embodiment, the reducing agent is at least one selected from hydrogen peroxide, sulfur dioxide, and sodium sulfite. It should be noted that the addition of the reducing agent reduces the iron, aluminum, copper, nickel, cobalt, manganese, and other metal elements in the lithium battery powder into their corresponding metal ions, facilitating impurity removal and recycling.

[0070] The following are examples, but it should be noted that the following examples do not exhaust all possible situations, and the materials used in the following examples are commercially available unless otherwise specified.

[0071] Example 1

[0072] Lithium-ion battery powder was mixed with pure water to obtain a slurry with a solid content of 20%. Sulfuric acid, a reducing agent, and the slurry were mixed and the pH was adjusted to 4.3 before a first-stage leaching and filtration process was performed, yielding a first leachate and a first leaching residue. The first leachate was then subjected to P2O4 extraction to remove impurities, resulting in a battery-grade nickel-cobalt-manganese solution. Sulfuric acid, a reducing agent, and the first leaching residue were mixed and the pH was adjusted to 1.5 before a second-stage leaching and filtration process was performed, yielding a second leachate and a second leaching residue. The second leachate was then subjected to impurity removal filtration, yielding a filtrate and a filter residue. The second leaching residue was then subjected to high-acid leaching and filtration to obtain battery-grade graphite raw material.

[0073] The conditions of the first leachate are shown in Table 1:

[0074]

[0075] The first leachate after P204 extraction and impurity removal is shown in Table 2:

[0076]

[0077] The second leachate obtained after circulating the first leaching residue three times through the first stage of leaching and filtration, and then performing the second stage of leaching and filtration, is shown in Table 3.

[0078]

[0079] The situation of the second high-acid leaching residue (battery-grade graphite raw material) is shown in Table 4:

[0080]

[0081] Example 2

[0082] Lithium-ion battery powder was mixed with pure water to obtain a slurry with a solid content of 20%. Sulfuric acid, a reducing agent, and the slurry were mixed and the pH was adjusted to 4.8 before a first-stage leaching and filtration process was performed, yielding a first leachate and a first leaching residue. The first leachate was then subjected to P2O4 extraction to remove impurities, yielding a battery-grade nickel-cobalt-manganese solution. Sulfuric acid, a reducing agent, and the first leaching residue were mixed and the pH was adjusted to 1.5 before a second-stage leaching and filtration process was performed, yielding a second leachate and a second leaching residue. The second leachate was then subjected to impurity removal filtration, yielding a filtrate and a filter residue. The second leaching residue was then subjected to high-acid leaching and filtration to obtain battery-grade graphite raw material.

[0083] The elemental contents of the first leachate are shown in Table 5:

[0084]

[0085] The elemental contents of the raffinate after P204 extraction and impurity removal are shown in Table 6:

[0086]

[0087] The elemental content of the second leachate obtained after circulating the first leaching residue three times through the first stage of leaching and filtration, followed by the second stage of leaching and filtration, is shown in Table 7.

[0088]

[0089] The elemental content of the second high-acid leaching residue (battery-grade graphite raw material) is shown in Table 8:

[0090]

[0091] Example 3

[0092] Prepare a 180 g / L sulfuric acid solution. Add pure water to the lithium battery powder to obtain a slurry with a solid content of 20%. Mix the sulfuric acid, reducing agent, and slurry, adjust the pH to 5.2, and perform a first-stage leaching and filtration operation to obtain a first leachate and a first leaching residue. Perform a P2O4 extraction to remove impurities from the first leachate to obtain a battery-grade nickel-cobalt-manganese solution. Mix the sulfuric acid, reducing agent, and the first leaching residue, adjust the pH to 1.5, and perform a second-stage leaching and filtration operation to obtain a second leachate and a second leaching residue. Perform a purification and filtration operation on the second leachate to obtain a filtrate and a filter residue. Perform a high-acid leaching and filtration operation on the second leaching residue to obtain battery-grade graphite raw material.

[0093] The elemental content of the first leachate is shown in Table 9:

[0094]

[0095] The elemental contents of the raffinate after P204 extraction and impurity removal are shown in Table 10:

[0096]

[0097] The elemental content of the second leachate obtained after circulating the first leaching residue three times through the first stage of leaching and filtration, followed by the second stage of leaching and filtration, is shown in Table 11:

[0098]

[0099] The elemental content of the second high-acid leaching residue (battery-grade graphite raw material) is shown in Table 12:

[0100]

[0101] Example 4

[0102] Lithium-ion battery powder was mixed with pure water to obtain a slurry with a solid content of 20%. Sulfuric acid, a reducing agent, and the slurry were mixed and the pH was adjusted to 5.7 before a first-stage leaching and filtration process was performed, yielding a first leachate and a first leaching residue. The first leachate was then subjected to P2O4 extraction to remove impurities, yielding a battery-grade nickel-cobalt-manganese solution. Sulfuric acid, a reducing agent, and the first leaching residue were mixed and the pH was adjusted to 1.5 before a second-stage leaching and filtration process was performed, yielding a second leachate and a second leaching residue. The second leachate was then subjected to impurity removal filtration, yielding a filtrate and a filter residue. The second leaching residue was then subjected to high-acid leaching and filtration to obtain battery-grade graphite raw material.

[0103] The elemental content of the first leachate is shown in Table 13:

[0104]

[0105] The elemental contents of the raffinate after P204 extraction and impurity removal are shown in Table 14:

[0106]

[0107] The elemental content of the second leachate obtained after circulating the first leaching residue three times through the first stage of leaching and filtration, followed by the second stage of leaching and filtration, is shown in Table 15.

[0108]

[0109] The elemental content of the second high-acid leaching residue (battery-grade graphite raw material) is shown in Table 16:

[0110]

[0111] Example 5

[0112] Lithium-ion battery powder was mixed with pure water to obtain a slurry with a solid content of 20%. Sulfuric acid, a reducing agent, and the slurry were mixed and the pH was adjusted to 6.0 before a first-stage leaching and filtration process was performed, yielding a first leachate and a first leaching residue. The first leachate was then subjected to P2O4 extraction to remove impurities, yielding a battery-grade nickel-cobalt-manganese solution. Sulfuric acid, a reducing agent, and the first leaching residue were mixed and the pH was adjusted to 1.5 before a second-stage leaching and filtration process was performed, yielding a second leachate and a second leaching residue. The second leachate was then subjected to impurity removal filtration, yielding a filtrate and a filter residue. The second leaching residue was then subjected to high-acid leaching and filtration to obtain battery-grade graphite raw material.

[0113] The elemental content of the first leachate is shown in Table 17:

[0114]

[0115] The elemental contents of the raffinate after P204 extraction and impurity removal are shown in Table 18:

[0116]

[0117] The elemental composition of the second leachate obtained after circulating the first leaching residue three times through the first stage of leaching and filtration, followed by the second stage of leaching and filtration, is shown in Table 19.

[0118]

[0119]

[0120] The elemental content of the second high-acid leaching residue (battery-grade graphite raw material) is shown in Table 20:

[0121]

[0122] Example 6

[0123] Lithium-ion battery powder was mixed with pure water to obtain a slurry with a solid content of 20%. Sulfuric acid, a reducing agent, and the slurry were mixed and the pH was adjusted to 4.0 before a first-stage leaching and filtration process was performed, yielding a first leachate and a first leaching residue. The first leachate was then subjected to P2O4 extraction to remove impurities, yielding a battery-grade nickel-cobalt-manganese solution. Sulfuric acid, a reducing agent, and the first leaching residue were mixed and the pH was adjusted to 1.5 before a second-stage leaching and filtration process was performed, yielding a second leachate and a second leaching residue. The second leachate was then subjected to impurity removal filtration, yielding a filtrate and a filter residue. The second leaching residue was then subjected to high-acid leaching and filtration to obtain battery-grade graphite raw material.

[0124] The elemental contents of the first leachate are shown in Table 21:

[0125]

[0126] The elemental contents of the raffinate after P204 extraction and impurity removal are shown in Table 22:

[0127]

[0128] The elemental content of the second leachate obtained after circulating the first leaching residue three times through the first stage of leaching and filtration, followed by the second stage of leaching and filtration, is shown in Table 23.

[0129]

[0130] The elemental content of the second high-acid leaching residue (battery-grade graphite raw material) is shown in Table 24:

[0131]

[0132] Comparative Example 1

[0133] Lithium-ion battery powder was mixed with pure water to obtain a slurry with a solid content of 20%. Sulfuric acid, a reducing agent, and the slurry were mixed and the pH was adjusted to 2.0 before a first-stage leaching and filtration process was performed, yielding a first leachate and a first leaching residue. The first leachate was then subjected to P2O4 extraction to remove impurities, resulting in a battery-grade nickel-cobalt-manganese solution. Sulfuric acid, a reducing agent, and the first leaching residue were mixed and the pH was adjusted to 1.5 before a second-stage leaching and filtration process was performed, yielding a second leachate and a second leaching residue. The second leachate was then subjected to impurity removal filtration, yielding a filtrate and a filter residue. The second leaching residue was then subjected to high-acid leaching and filtration to obtain battery-grade graphite raw material.

[0134] The elemental content of the first leachate is shown in Table 25:

[0135]

[0136] The elemental contents of the raffinate after P204 extraction and impurity removal are shown in Table 26:

[0137]

[0138] The elemental composition of the second leachate obtained after circulating the first leaching residue three times through the first stage of leaching and filtration, followed by the second stage of leaching and filtration, is shown in Table 27.

[0139]

[0140] The elemental content of the second high-acid leaching residue (battery-grade graphite raw material) is shown in Table 28:

[0141]

[0142] Comparative Example 2

[0143] Lithium-ion battery powder was mixed with pure water to obtain a slurry with a solid content of 20%. Sulfuric acid, a reducing agent, and the slurry were mixed and the pH was adjusted to 2.5 before a first-stage leaching and filtration process was performed to obtain a first leachate and a first leaching residue. The first leachate was then subjected to P2O4 extraction to remove impurities, yielding a battery-grade nickel-cobalt-manganese solution. Sulfuric acid, a reducing agent, and the first leaching residue were mixed and the pH was adjusted to 1.5 before a second-stage leaching and filtration process was performed to obtain a second leachate and a second leaching residue. The second leachate was then subjected to impurity removal filtration to obtain a filtrate and a filter residue. The second leaching residue was then subjected to high-acid leaching and filtration to obtain battery-grade graphite raw material.

[0144] The elemental content of the first leachate is shown in Table 29:

[0145]

[0146] The elemental contents of the raffinate after P204 extraction and impurity removal are shown in Table 30:

[0147]

[0148] The elemental content of the second leachate obtained after circulating the first leaching residue three times through the first stage of leaching and filtration, followed by the second stage of leaching and filtration, is shown in Table 31:

[0149]

[0150] The elemental content of the second high-acid leaching residue (battery-grade graphite raw material) is shown in Table 32:

[0151]

[0152] Comparative Example 3

[0153] Lithium-ion battery powder was mixed with pure water to obtain a slurry with a solid content of 20%. Sulfuric acid, a reducing agent, and the slurry were mixed and the pH was adjusted to 3.0 before a first-stage leaching and filtration process was performed, yielding a first leachate and a first leaching residue. The first leachate was then subjected to P2O4 extraction to remove impurities, resulting in a battery-grade nickel-cobalt-manganese solution. Sulfuric acid, a reducing agent, and the first leaching residue were mixed and the pH was adjusted to 1.5 before a second-stage leaching and filtration process was performed, yielding a second leachate and a second leaching residue. The second leachate was then subjected to impurity removal filtration, yielding a filtrate and a filter residue. The second leaching residue was then subjected to high-acid leaching and filtration to obtain battery-grade graphite raw material.

[0154] The elemental content of the first leachate is shown in Table 33:

[0155]

[0156] The elemental contents of the raffinate after P204 extraction and impurity removal are shown in Table 34:

[0157]

[0158]

[0159] The elemental composition of the second leachate obtained after circulating the first leaching residue three times through the first stage of leaching and filtration, followed by the second stage of leaching and filtration, is shown in Table 35.

[0160]

[0161] The elemental content of the second high-acid leaching residue (battery-grade graphite raw material) is shown in Table 36:

[0162]

[0163] Tables 1 to 36 show that when the pH value of the first leaching and filtration operation is not between 4 and 6, the content of iron, aluminum, and copper elements in the first leachate increases significantly, resulting in the raffinate after P204 extraction not meeting the requirements for battery-grade nickel, cobalt, and manganese. This indicates that strictly controlling the pH value between 4 and 6 in the first leaching and filtration operation results in lower iron, aluminum, and copper content in the first leachate, and the raffinate after P204 extraction meets the requirements for battery-grade nickel, cobalt, and manganese. This not only simplifies the recycling process of battery-grade nickel, cobalt, and manganese but also saves on auxiliary material consumption. Furthermore, it simplifies the lithium battery powder recycling process and aligns with the concept of green recycling. Simultaneously, the leaching residue after both the first and second high-acid leaching and filtration operations meets the standards for battery-grade graphite raw materials. This demonstrates that by incorporating both high-acid leaching and filtration operations, not only can battery-grade graphite raw materials be recovered, but the cost of disposing of leaching residue as hazardous or solid waste can also be saved.

[0164] Compared with the prior art, this application has at least the following advantages:

[0165] 1. The lithium-ion battery powder recycling method of this application involves mixing sulfuric acid, a reducing agent, and a slurry, followed by a first-stage leaching and filtration operation. The pH value is strictly controlled between 4 and 6, and under the action of the reducing agent, iron, aluminum, and copper elements in the lithium-ion battery powder precipitate, forming the first leaching residue. Filtration separates the first leaching residue from the first leaching solution. The first leaching solution is then subjected to P204 extraction to remove impurities, specifically by using P204 extractant to remove calcium ions, thereby preparing a battery-grade nickel-cobalt-manganese solution. Therefore, a full extraction process is unnecessary to prepare the battery-grade nickel-cobalt-manganese solution, effectively reducing the consumption of auxiliary materials and simplifying the preparation method. This simplifies the lithium-ion battery powder recycling process, thereby improving the recycling efficiency and reducing the recycling cost.

[0166] 2. The lithium battery powder recycling method of this application involves mixing sulfuric acid, a reducing agent, and a first leaching residue, followed by a second-stage leaching and filtration operation. The pH value is strictly controlled between 1 and 2, and a second leaching residue is formed under the action of the reducing agent. Simultaneously, iron, aluminum, and copper elements in the first leaching residue are leached out, forming a second leachate. Filtration separates the second leaching residue and the second leachate. Further impurity removal filtration of the second leachate yields a filter residue, which is a mixed precipitate of iron, aluminum, and copper, achieving a good impurity removal and recycling effect. Furthermore, since the second leaching residue is rich in graphite, high-acid leaching and filtration of the second leaching residue yields battery-grade graphite raw materials, enabling graphite recycling and reuse, while saving the cost of disposing of the second leaching residue as solid waste or hazardous waste.

[0167] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0168] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A recycling method based on lithium extraction from battery powder, characterized in that, The method comprises the following steps: adding pure water to the lithium extraction battery powder to perform a slurry operation to obtain a slurry with a solid content of 20%-30%; mixing sulfuric acid, a reducing agent, and the slurry to perform a first-stage leaching and filtration operation to obtain a first leaching solution and a first leaching residue; performing P204 extraction and impurity removal on the first leaching solution to obtain a battery-grade nickel-cobalt-manganese solution; dissolving the first leaching residue; detecting the content of the dissolved first leaching residue; wherein judging the content of the first leaching residue, and the specific judging operation is as follows: when the mass percentage of iron and aluminum content in the first leaching residue is greater than or equal to 5%, mixing the sulfuric acid, the reducing agent, and the first leaching residue to perform a second-stage leaching and filtration operation; when the mass percentage of iron and aluminum content in the first leaching residue is less than 5%, mixing the sulfuric acid, the reducing agent, the first leaching residue, and the slurry to perform a first-stage leaching and filtration operation; mixing the sulfuric acid, the reducing agent, and the first leaching residue to perform a second-stage leaching and filtration operation to obtain a second leaching solution and a second leaching residue; wherein the reducing agent is at least one of hydrogen peroxide, sulfur dioxide, and sodium sulfite performing impurity removal and filtration on the second leaching solution to obtain a filtrate and a filtration residue; wherein the pH value in the first-stage leaching and filtration operation is 4.0-4.8; the pH value in the second-stage leaching and filtration operation is 1.5; performing high-acid leaching and filtration on the second leaching residue to obtain a battery-grade graphite raw material; wherein the specific operation steps for performing high-acid leaching and filtration on the second leaching residue are as follows: mixing the sulfuric acid, the reducing agent, and the second leaching residue to perform a first high-acid leaching and filtration operation to obtain a first high-acid leaching residue and a first high-acid leaching solution; wherein the acidity of the first high-acid leaching and filtration operation is 200g / L-300g / L; mixing the sulfuric acid, the reducing agent, and the first high-acid leaching residue to perform a second high-acid leaching and filtration operation to obtain the battery-grade graphite raw material; wherein the acidity of the second high-acid leaching and filtration operation is 300g / L-500g / L; and the temperature of the first high-acid leaching and filtration operation and the second high-acid leaching and filtration operation is both 80℃-100℃.

2. The recycling method based on lithium extraction battery powder according to claim 1, wherein the specific operation steps for performing P204 extraction and impurity removal on the first leaching solution to obtain a battery-grade nickel-cobalt-manganese solution are as follows: adding a P204 extractant to the first leaching solution to perform an extraction operation to obtain the battery-grade nickel-cobalt-manganese solution.

3. The recycling method based on lithium extraction battery powder according to claim 1, wherein the specific operation steps for performing impurity removal and filtration on the second leaching solution are as follows: adding an active metal to the second leaching solution to perform copper removal; adding an alkaline salt to the second leaching solution after copper removal to perform a filtration operation to obtain a filtration residue and a filtrate.

4. The recycling method based on lithium extraction battery powder according to claim 3, wherein ​ ​ The active metal is one of iron powder, manganese powder or nickel powder. 5.The recycling method according to claim 3, wherein the lithium extraction battery powder is a lithium cobalt battery powder. The alkaline salt is industrial-grade sodium carbonate or industrial-grade sodium hydroxide. 6.The recycling method according to claim 1, wherein the lithium extraction battery powder is a lithium cobalt battery powder. After the step of performing the first high-acid leaching and filtration operation after mixing the sulfuric acid, the reducing agent and the second leaching residue, and before the step of performing the second high-acid leaching and filtration operation after mixing the sulfuric acid, the reducing agent and the first high-acid leaching residue, the recycling method further comprises the following step: After mixing the sulfuric acid, the reducing agent, the first high-acid leaching solution and the first leaching residue, performing the second leaching and filtration operation.

7. The recycling method based on lithium-extraction battery powder according to claim 1, characterized in that, After the step of performing the second high-acid leaching and filtration operation after mixing the sulfuric acid, the reducing agent and the first high-acid leaching residue to obtain the battery-grade graphite raw material, the recycling method further comprises the following step: After mixing the sulfuric acid, the reducing agent, the second high-acid leaching solution and the second leaching residue, performing the first high-acid leaching and filtration operation. 8.The recycling method according to claim 1, wherein the temperature of the first leaching and filtration operation is 80-100 ℃. The temperature of the first leaching and filtration operation is 80-100 ℃.

Images