Method for recovering ternary positive electrode material in waste lithium battery

Abstract

The invention discloses a method for recycling a ternary positive electrode material in a waste lithium battery, and relates to the technical field of lithium battery recycling, the method comprises the following steps: treating a ternary positive plate of the waste lithium ion battery to obtain ternary material powder; mixing the ternary material powder with a phytic acid solution, heating to a preset temperature, and adding a reducing agent for constant-temperature stirring reaction; and carrying out solid-liquid separation to obtain a leaching solution containing metal ions. According to the method, the ternary positive electrode material in the waste lithium battery is efficiently recycled under a mild condition.

Description

Technical Field

[0001] This application relates to the field of lithium battery recycling technology, and in particular to a method for recycling ternary cathode materials from waste lithium batteries. Background Technology

[0002] With the rapid development of new energy vehicles, energy storage systems, and portable electronic devices, the production and consumption of lithium-ion batteries have increased dramatically, leading to the generation and accumulation of a large number of waste lithium-ion batteries. Ternary cathode materials (lithium nickel cobalt manganese oxide) have become one of the mainstream cathode materials for power batteries due to their advantages such as high energy density and long cycle life. However, ternary materials contain a large amount of valuable metals, such as lithium, nickel, cobalt, and manganese. These metal resources are scarce and expensive, and their indiscriminate disposal will cause serious resource waste and environmental pollution.

[0003] Currently, the recycling methods for spent ternary lithium batteries mainly fall into two categories: pyrometallurgy and hydrometallurgy. Pyrometallurgy decomposes organic matter and reduces metal oxides into alloys through high-temperature roasting. Although the process is simple, it consumes a lot of energy, produces a large amount of waste gas, and is difficult to achieve efficient lithium recovery. Hydrometallurgy is currently the mainstream recycling process, typically employing a technical route of acid leaching-separation purification-product regeneration. Traditional hydrometallurgy often uses strong inorganic acids such as sulfuric acid and hydrochloric acid. Although the leaching efficiency is relatively high, it also has significant drawbacks: strong acids are highly corrosive, requiring high-quality equipment materials and increasing investment and maintenance costs; the leaching process may produce toxic and harmful gases such as chlorine and sulfur dioxide, posing safety hazards and environmental risks; and subsequent treatment of waste acid and heavy metal waste liquid is difficult and can easily cause secondary pollution.

[0004] The above content is only used to help understand the technical solution of this application and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this application is to provide a method for recycling ternary cathode materials from waste lithium batteries, aiming to achieve efficient recycling of ternary cathode materials from waste lithium batteries under mild conditions.

[0006] To achieve the above objectives, this application proposes a method for recycling ternary cathode materials from spent lithium batteries, the method comprising: The ternary cathode sheet of waste lithium-ion batteries is processed to obtain ternary material powder; The ternary material powder is mixed with phytic acid solution, heated to a preset temperature, and a reducing agent is added for constant temperature stirring reaction; Solid-liquid separation yields a leachate containing metal ions.

[0007] In one feasible embodiment, the reducing agent includes hydrogen peroxide and / or sodium thiosulfate.

[0008] In one feasible embodiment, the hydrogen peroxide has a mass fraction of 26% to 33%; And / or, the concentration of the sodium thiosulfate is 50 g / L to 300 g / L.

[0009] In one feasible embodiment, the concentration of the phytic acid solution is 0.1 mol / L to 1.5 mol / L.

[0010] In a feasible embodiment, the solid-liquid ratio of the ternary material to the phytic acid solution is 50 g / L to 500 g / L.

[0011] In one feasible embodiment, the reaction time of the isothermal stirring reaction is 30 min to 120 min; And / or, the preset temperature is 30℃~100℃.

[0012] In one feasible embodiment, the solid-liquid separation is performed by hot filtration.

[0013] In a feasible embodiment, the leaching rate of metal ions in the leachate containing Li, Ni, Co and Mn is greater than or equal to 98%.

[0014] In one feasible embodiment, the method further includes: The leachate and the first extractant are mixed, and sodium hydroxide is added for saponification to perform the first extraction, thereby obtaining the first aqueous phase. The first extractant includes di(2-ethylhexyl) phosphate and sulfonated kerosene. The first aqueous phase and the second extractant are mixed and a second extraction is performed to obtain a manganese-containing organic phase and a second aqueous phase, wherein the second extractant includes 2-ethylhexyl phosphate mono-2-ethylhexyl ester and sulfonated kerosene; The second aqueous phase and the second extractant are mixed and a third extraction is performed to obtain a cobalt-containing organic phase and a third aqueous phase; The third aqueous phase and the second extractant are mixed and a fourth extraction is performed to obtain a nickel-containing organic phase and a fourth aqueous phase; Sodium carbonate was added to the fourth aqueous phase to obtain lithium carbonate.

[0015] In one feasible embodiment, the pH of the leachate is adjusted to 2-4 during the first extraction process; And / or, during the second extraction process, the pH of the first aqueous phase is adjusted to 3~3.5; And / or, during the third extraction process, the pH of the second aqueous phase is adjusted to 4.5~5; And / or, during the fourth extraction process, the pH of the third aqueous phase is adjusted to 5.5~6; And / or, after adding sodium carbonate to the fourth aqueous phase, adjust the pH to 10-11.

[0016] One or more technical solutions proposed in this application have at least the following technical effects: The ternary cathode sheet of a spent lithium-ion battery is decomposed to obtain ternary material powder; the ternary material powder is mixed with a phytic acid solution, and the strong complexing ability of phytic acid and the efficient reducing effect of the composite reducing agent produce a synergistic effect, which can be used to leach valuable metal ions from the ternary cathode material, replacing traditional strong inorganic acids such as sulfuric acid and hydrochloric acid, thus avoiding the safety risks and gas pollution caused by using strong acids; heating to a preset temperature and adding a reducing agent to react; combined with appropriate temperature conditions, efficient leaching can be achieved; solid-liquid separation yields a leachate containing metal ions, which can simultaneously and efficiently leach metal ions from the ternary cathode material crystals. The embodiments of this application achieve efficient recycling of ternary cathode materials from spent lithium batteries under mild conditions. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0018] 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, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic flowchart illustrating an embodiment of the recycling method for ternary cathode materials in waste lithium batteries according to this application.

[0020] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0022] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the method for recycling ternary cathode materials from spent lithium batteries according to this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0023] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0024] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0025] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0026] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0027] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0028] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0029] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the technical solution of this application is further described below in conjunction with the accompanying drawings and embodiments. However, this application is not limited to the listed embodiments, but should also include any other well-known modifications within the scope of the claims made in this application.

[0030] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of this application. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0031] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0032] Currently, the recycling methods for spent ternary lithium batteries mainly fall into two categories: pyrometallurgy and hydrometallurgy. Pyrometallurgy decomposes organic matter and reduces metal oxides into alloys through high-temperature roasting. Although the process is simple, it consumes a lot of energy, produces a large amount of waste gas, and is difficult to achieve efficient lithium recovery. Hydrometallurgy is currently the mainstream recycling process, typically employing a technical route of acid leaching-separation purification-product regeneration. Traditional hydrometallurgy often uses strong inorganic acids such as sulfuric acid and hydrochloric acid. Although the leaching efficiency is relatively high, it also has significant drawbacks: strong acids are highly corrosive, requiring high-quality equipment materials and increasing investment and maintenance costs; the leaching process may produce toxic and harmful gases such as chlorine and sulfur dioxide, posing safety hazards and environmental risks; and subsequent treatment of waste acid and heavy metal waste liquid is difficult and can easily cause secondary pollution.

[0033] This application embodiment decomposes ternary cathode sheets from spent lithium-ion batteries to obtain ternary material powder. The ternary material powder is mixed with phytic acid solution. The strong complexing ability of phytic acid and the efficient reducing effect of the composite reducing agent produce a synergistic effect, which can be used to leach valuable metal ions from the ternary cathode material, replacing traditional strong inorganic acids such as sulfuric acid and hydrochloric acid, thus avoiding the safety risks and gas pollution associated with using strong acids. The mixture is heated to a preset temperature, and a reducing agent is added to initiate the reaction. Efficient leaching can be achieved under relatively low temperature and conditions. Solid-liquid separation yields a leachate containing metal ions. This method can simultaneously and efficiently leach Li, Ni, Co, and Mn from the ternary cathode material crystals. This application embodiment achieves efficient recycling of ternary cathode materials from spent lithium batteries under mild conditions.

[0034] Based on this, embodiments of this application provide a method for recycling ternary cathode materials from waste lithium batteries, referring to... Figure 1 In this embodiment, the method includes: Step S10: Decompose the ternary cathode sheet of the waste lithium-ion battery to obtain ternary material powder. In one feasible embodiment, the ternary cathode sheet of a spent lithium-ion battery typically consists of a current collector (such as aluminum foil) and a ternary active material coated thereon. The purpose of decomposing the cathode sheet is to separate the active material from the current collector, obtaining ternary material powder for subsequent recycling of its metal elements. Common decomposition methods include physical and chemical methods. Physical methods use mechanical crushing, grinding, etc., to detach the ternary active material from the current collector, and then use sieving, air classification, etc., to separate the current collector and the ternary material powder. Chemical methods use suitable organic solvents or acid / alkali solutions to dissolve the binder, thereby separating the ternary active material from the current collector.

[0035] Alternatively, the ternary cathode material is lithium nickel cobalt manganese oxide, and the ratio of nickel, cobalt, and manganese can be adjusted according to actual needs.

[0036] Optionally, after obtaining the ternary material powder, the content of each valuable metal is tested and determined to clarify the amount of each substance to be added during the subsequent recovery of valuable metal elements.

[0037] Step S20: Mix the ternary material powder with the phytic acid solution and heat to a preset temperature, then add a reducing agent to carry out a constant temperature reaction; In one feasible embodiment, phytic acid (inositol hexaphosphate) has multiple phosphate groups that can form stable complexes with metal ions. In the recycling of spent lithium-ion batteries, phytic acid can undergo complexation reactions with metal ions such as Li, Ni, Co, and Mn in ternary material powders, facilitating the dissolution of metal ions from the solid powder. Heating can promote the complexation reaction between phytic acid and metal ions, improving the leaching efficiency of metal ions. Heating can also shift the reaction in a direction favorable to the dissolution of metal ions, increasing the leaching rate. Furthermore, in the ternary material powder, metals such as Co and Mn may exist in high valence states (e.g., Co...). 3+ Mn 4+ High-valence metal ions have relatively poor solubility in phytic acid solutions. Adding a reducing agent can reduce high-valence metal ions to lower-valence states (such as Co). 2+ Mn 2+ This increases their solubility in phytic acid solution and promotes the leaching of metal ions.

[0038] Phytic acid is a natural organic compound with good biodegradability. Compared with traditional strong acid leaching agents (such as sulfuric acid and hydrochloric acid), using phytic acid as a leaching agent can reduce environmental pollution.

[0039] In one feasible embodiment, the concentration of the phytic acid solution is 0.1 mol / L to 1.5 mol / L.

[0040] Optionally, the concentration of the phytic acid solution can be 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, and 1.5 mol / L. If the concentration of the phytic acid solution is too low, it cannot complex the valuable metal ions in the ternary material powder; if the concentration of the phytic acid solution is too high, the leaching rate of the metal ions will not change significantly, and it may even inhibit mass transfer efficiency due to the increased viscosity of the phytic acid solution, and may form colloids or precipitates, affecting subsequent separation. A suitable concentration of the phytic acid solution ensures that the overall reaction proceeds under suitable acidic conditions, avoiding the hydrolysis of metal ions from affecting the final leaching rate; a suitable concentration of the phytic acid solution also ensures sufficient collision probability between phytic acid molecules and metal ions, forming stable complexes and improving the leaching rate of metal ions.

[0041] In one feasible implementation, the solid-liquid ratio of the ternary material to the phytic acid solution is 50 g / L to 500 g / L.

[0042] Optionally, the solid-liquid ratio of the ternary material to the phytic acid solution can be 50 g / L, 100 g / L, 150 g / L, 200 g / L, 250 g / L, 300 g / L, 350 g / L, 400 g / L, 450 g / L, and 500 g / L. The solid-liquid ratio affects the contact area and degree of contact between the ternary material and the phytic acid solution. When the solid-liquid ratio is between 50 g / L and 500 g / L, the ternary material powder can be well dispersed in the phytic acid solution, allowing phytic acid molecules sufficient opportunity to contact and react with the metal oxides in the ternary material. If the solid-liquid ratio is too high (i.e., too much ternary material and too little phytic acid solution), the ternary material powder may agglomerate, preventing some of the powder from fully contacting the phytic acid and thus reducing the leaching efficiency of metal ions. If the solid-liquid ratio is too low (i.e., too much phytic acid solution and too little ternary material), although sufficient contact may be achieved, it will increase the workload and cost of subsequent leachate treatment and also reduce the metal ion leaching rate. Furthermore, after the leaching process, solid-liquid separation is required to obtain a leachate containing metal ions. If the solid-liquid ratio is too high, problems such as difficult filtration and low separation efficiency may occur during solid-liquid separation; while if the solid-liquid ratio is too low, the separation workload will increase.

[0043] In one feasible implementation, the reducing agent includes hydrogen peroxide and / or sodium thiosulfate.

[0044] Optionally, in ternary cathode materials, metallic elements such as cobalt (Co), manganese (Mn), and nickel (Ni) may exist in higher oxidation states, such as Co. 3+ Mn4+ Ni 3+ Etc. Hydrogen peroxide can reduce high-valence metal ions to more soluble low-valence states, for example, reducing Co... 3+ Restored to Co 2+ Mn 4+ Restored to Mn 2+ Ni 3+ Reduced to Ni 2+ This facilitates the leaching of metal ions from the ternary material powder into the phytic acid solution. Furthermore, the decomposition products of hydrogen peroxide are water and oxygen, which do not introduce new impurity ions into the leachate, minimizing the impact on subsequent metal ion separation and purification processes. This makes the recycling process more environmentally friendly and aligns with sustainable development requirements. Hydrogen peroxide can react with ternary materials at room temperature or lower, eliminating the need for stringent reaction conditions and reducing energy consumption and equipment requirements. Simultaneously, the relatively fast reaction rate improves recycling efficiency.

[0045] Optionally, the sulfur element in sodium thiosulfate (Na₂S₂O₃) has multiple oxidation states and can donate electrons in the reaction to reduce high-valence metal ions. It can effectively reduce Co in ternary materials. 3+ Mn 4+ When reduced to a lower oxidation state, it promotes metal leaching. Sodium thiosulfate is relatively stable and inexpensive, which can reduce costs.

[0046] Optionally, hydrogen peroxide and sodium thiosulfate can be used together to achieve a synergistic effect. Different reducing agents may have better reduction effects at different reaction stages or for different metal ions. Combined use can more comprehensively and efficiently reduce various high-valence metal ions in ternary materials, further improving the metal leaching rate, thereby enhancing the recycling efficiency and quality of ternary cathode materials from waste lithium batteries.

[0047] In one feasible embodiment, the mass fraction of hydrogen peroxide is 26% to 33%; Optionally, the mass fraction of hydrogen peroxide can be 26%, 27%, 28%, 29%, 30%, 31%, 32%, and 33%, etc. If the mass fraction of hydrogen peroxide is too low, the reducing power is insufficient, and it cannot effectively reduce high-valence metal ions in the ternary material powder to low-valence states, resulting in a reduced metal ion leaching rate. Conversely, if the mass fraction of hydrogen peroxide is too high, the reaction may become too vigorous, generating a large amount of oxygen, increasing the pressure and safety risks of the reaction system, and potentially wasting hydrogen peroxide.

[0048] In one feasible implementation, the concentration of sodium thiosulfate is 50 g / L to 300 g / L.

[0049] Optionally, the concentration of sodium thiosulfate can be 50 g / L, 100 g / L, 120 g / L, 140 g / L, 160 g / L, 180 g / L, 200 g / L, 220 g / L, 240 g / L, 260 g / L, 280 g / L, and 300 g / L. When the concentration of sodium thiosulfate is too low, the contact opportunity between sodium thiosulfate and the ternary material powder is reduced, the reaction rate is slower, the time required for metal ion leaching is prolonged, and the recovery efficiency is reduced. As the concentration of sodium thiosulfate increases, the reaction rate accelerates, but when the concentration is too high, the increase in reaction rate is no longer significant, and it may even increase costs.

[0050] In one feasible implementation, the reaction time for adding the reducing agent is 30 min to 120 min.

[0051] Optionally, the reaction time for adding the reducing agent can be 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, and 120 min, etc. The reaction time determines the degree of reduction reaction and metal ion leaching. If the reaction time is too short, the reduction reaction will be incomplete, and the metal ions cannot be completely leached from the ternary material powder, resulting in a decrease in the leaching rate. As the reaction time increases, the metal ion leaching rate will gradually increase, but after the reaction proceeds to a certain extent, the increase in the leaching rate will become slow.

[0052] In one feasible implementation, the preset temperature is 30℃~100℃.

[0053] Optionally, the preset temperature can be 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, and 100℃, etc. When the preset temperature is too low, the thermal motion of molecules slows down, the reaction rate between the reducing agent and the ternary material is slow, and the leaching efficiency of metal ions is low. As the preset temperature increases, the reaction rate accelerates, promoting the leaching of metal ions. However, when the temperature is too high, it may lead to accelerated decomposition of reducing agents such as hydrogen peroxide, reducing the utilization rate of the reducing agent, and also increasing energy consumption and equipment costs. Furthermore, excessively high temperatures also increase the overall reaction risk to some extent.

[0054] Optionally, hydrogen peroxide is prone to decomposition at higher temperatures. Therefore, during the addition of hydrogen peroxide, it is necessary to control the dropping rate to avoid the decomposition of hydrogen peroxide affecting the reduction reaction process and thus affecting the leaching rate of metal ions.

[0055] Step S30: Solid-liquid separation to obtain a leachate containing metal ions, wherein the metal ions include Li, Ni, Co and Mn.

[0056] In one feasible embodiment, after the leaching process, metal ions such as Li, Ni, Co, and Mn in the ternary material powder dissolve in the phytic acid solution in the form of complexes, while unreacted impurities (such as insoluble carbon materials, other sparingly soluble substances, etc.) exist in solid form. Through solid-liquid separation, the leachate containing metal ions can be separated from the solid impurities, providing a pure solution for subsequent further extraction and separation of metal ions.

[0057] Alternatively, solid-liquid separation can include methods such as filtration and centrifugation.

[0058] Optionally, the solid-liquid separation method is hot filtration. Hot filtration requires maintaining the fluidity of the solution at a certain temperature to separate the leachate containing metal ions from the solid waste residue. At a certain temperature, the solubility of metal ions is higher, which is beneficial to improving the leaching rate of metal ions.

[0059] In one feasible embodiment, the leaching rate of metal ions in the leachate containing metal ions is greater than or equal to 98%.

[0060] In one feasible embodiment, by precisely controlling and synergistically applying technical means such as phytic acid solution concentration, solid-liquid ratio, type and concentration of reducing agent, reaction time, and reaction temperature, favorable conditions are created for the efficient leaching of metal ions from ternary cathode materials of waste lithium batteries. This achieves the goal of a metal ion leaching rate of greater than or equal to 98% in the leachate containing metal ions, effectively improving the recycling efficiency and resource utilization rate of ternary cathode materials in waste lithium batteries.

[0061] In another feasible embodiment, after obtaining the leachate containing metal ions, the method further includes: Step A10: Mix the leachate and the first extractant, add sodium hydroxide for saponification, and perform the first extraction to obtain the first aqueous phase. The first extractant includes di(2-ethylhexyl) phosphate and sulfonated kerosene. In one feasible embodiment, during the mixing process, the first extractant selectively extracts some impurity metal ions (such as iron, aluminum, etc.) from the leachate, thereby separating these impurities from the leachate and obtaining a relatively pure first aqueous phase.

[0062] The first extractant consists of di(2-ethylhexyl) phosphate (P204) and sulfonated kerosene. P204 is a commonly used acidic phosphorus-based extractant with good extraction performance. Sulfonated kerosene acts as a diluent, reducing the viscosity of the extractant and improving the two-phase separation performance during the extraction process.

[0063] The addition of sodium hydroxide for saponification is to remove the H+ from P2O4. + Partial or complete replacement with Na +This forms a saponified extractant. The saponified extractant reduces the release of hydrogen ions during extraction, prevents excessive drop in the pH of the aqueous phase, and facilitates the extraction of metal ions.

[0064] In one feasible implementation, the pH of the leachate is adjusted to 2-4 during the first extraction process.

[0065] The initial pH of the leachate should be controlled between 2 and 4. Within this pH range, Fe... 3+ Al 3+ Cu 2+ Impurities such as Ni, Co, Mn, and Li are preferentially extracted into the organic phase, while Ni, Co, Mn, and Li remain primarily in the aqueous phase.

[0066] Optionally, the first extraction process typically employs 3 to 5 stages of countercurrent extraction to ensure thorough removal of impurities.

[0067] After the first extraction, the first aqueous phase contains Ni, Co, Mn, and Li.

[0068] Step A20: The first aqueous phase and the second extractant are mixed and a second extraction is performed to obtain a manganese-containing organic phase and a second aqueous phase. The second extractant includes 2-ethylhexyl phosphate mono-2-ethylhexyl ester and sulfonated kerosene. In a feasible embodiment, during the second extraction process, 2-ethylhexyl phosphate mono-2-ethylhexyl ester (P507) preferentially undergoes a complexation reaction with manganese ions in the first aqueous phase, extracting the manganese ions from the aqueous phase into the organic phase to form a manganese-containing organic phase. Other metal ions (such as cobalt, nickel, lithium, etc.) remain in the second aqueous phase.

[0069] In one feasible implementation, the pH of the first aqueous phase is adjusted to 3-3.5 during the second extraction process.

[0070] Adjust the pH of the first aqueous phase to 3-3.5, and then perform multi-stage (e.g., 4-6 stages) extraction using the P507 organic phase. Mn 2+ It is preferentially extracted into the organic phase, while Co 2+ Ni 2+ L i+ It remains in the second aqueous phase.

[0071] Optionally, the manganese-containing organic phase can be back-extracted with dilute sulfuric acid to obtain a pure manganese sulfate solution, which can be used to prepare battery-grade manganese sulfate or electrolytic manganese.

[0072] Step A30: Mix the second aqueous phase and the second extractant, and perform a third extraction to obtain a cobalt-containing organic phase and a third aqueous phase; In one feasible embodiment, manganese ions have been separated after the second extraction. During the third extraction, the second extractant (P507) undergoes a complexation reaction with cobalt ions in the second aqueous phase, extracting the cobalt ions from the aqueous phase into the organic phase to form a cobalt-containing organic phase. Nickel ions and lithium ions remain in the third aqueous phase.

[0073] In one feasible implementation, the pH of the second aqueous phase is adjusted to 4.5-5 during the third extraction process.

[0074] Optionally, the pH of the second aqueous phase is adjusted to 4.5–5.0 using NaOH or Na₂CO₃ solution. Multi-stage (e.g., 6–8 stages) extraction is then performed using the P507 organic phase. Co 2+ Cobalt-containing organic phases are preferentially extracted, while Ni... 2+ and Li + It remains in the third aqueous phase.

[0075] Optionally, the cobalt-containing organic phase is usually first washed with dilute acid to remove the small amount of nickel co-extracted, and then back-extracted with a stronger acid (such as 2~3 mol / L H2SO4 or HCl) to obtain a high-purity cobalt chloride or cobalt sulfate solution.

[0076] Step A40: Mix the third aqueous phase and the second extractant, and perform a fourth extraction to obtain a nickel-containing organic phase and a fourth aqueous phase; In one feasible embodiment, after the third extraction, cobalt ions have been separated. During the fourth extraction, the second extractant (P507) undergoes a complexation reaction with nickel ions in the third aqueous phase, extracting the nickel ions from the aqueous phase into the organic phase to form a nickel-containing organic phase. At this point, lithium ions are mainly remaining in the fourth aqueous phase.

[0077] In one feasible implementation, the pH of the third aqueous phase is adjusted to 5.5-6 during the fourth extraction process.

[0078] Optionally, the pH of the third aqueous phase is adjusted to 5.5-6.0, and nickel ions are preferentially extracted using P507, while lithium ions remain in the fourth aqueous phase.

[0079] Alternatively, the nickel-containing organic phase can be back-extracted using dilute sulfuric acid to obtain a nickel sulfate solution.

[0080] Step A50: Sodium carbonate is added to the fourth aqueous phase to obtain lithium carbonate.

[0081] In one feasible embodiment, a preheated saturated sodium carbonate solution is slowly added at 90-95°C to react and generate lithium carbonate precipitate. The temperature, addition rate, and stirring intensity are controlled during the addition of sodium carbonate to control the crystal morphology and particle size of lithium carbonate. In one feasible embodiment, sodium carbonate is added to the fourth aqueous phase, and the pH is adjusted to 10-11.

[0082] This embodiment decomposes ternary cathode sheets from spent lithium-ion batteries to obtain ternary material powder. The ternary material powder is then mixed with a phytic acid solution. The strong complexing ability of phytic acid and the efficient reducing effect of the composite reducing agent create a synergistic effect, allowing for the leaching of valuable metal ions from the ternary cathode material. This replaces traditional strong inorganic acids such as sulfuric acid and hydrochloric acid, avoiding the safety risks and gas pollution associated with strong acids. The mixture is heated to a preset temperature, and a reducing agent is added to initiate the reaction. Efficient leaching is achieved under relatively low temperature and conditions. Solid-liquid separation yields a leachate containing metal ions, enabling the simultaneous and efficient leaching of metal ions from the cathode material crystals. This embodiment achieves efficient recycling of ternary cathode materials from spent lithium batteries under mild conditions. Furthermore, this embodiment uses fractional extraction to separate Li, Ni, Co, and Mn from the leachate for subsequent reprocessing of ternary cathode materials.

[0083] In order to enable those skilled in the art to clearly understand the details and operations of the above embodiments of this application, and to demonstrate the significant improvement in performance of the embodiments of this application, the above technical solutions are illustrated below through multiple embodiments.

[0084] Example 1 The ternary cathode material from waste lithium batteries was disassembled, peeled, and sieved to obtain ternary material powder. 10g of the ternary material powder was mixed with 200mL of 0.5mol / L phytic acid solution; the mixture was heated to 80℃, and 2.2ml of 27% hydrogen peroxide was added, followed by constant-temperature stirring for 40min; solid-liquid separation was performed to obtain a leachate containing metal ions. The concentrations of Li, Co, Ni, and Mn in the leachate were analyzed by ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry), and the leaching rate was calculated.

[0085] Example 2 The ternary cathode material from waste lithium batteries was disassembled, peeled, and sieved to obtain ternary material powder. 10g of the ternary material powder was mixed with 200mL of 0.5mol / L phytic acid solution; the mixture was heated to 80℃, and 10mL of 200g / L sodium thiosulfate solution was added, followed by constant-temperature stirring for 40min; solid-liquid separation was performed to obtain a leachate containing metal ions. The concentrations of Li, Co, Ni, and Mn in the leachate were analyzed by ICP-OES to calculate the leaching rate.

[0086] Example 3 The ternary cathode material from spent lithium batteries was disassembled, peeled, and sieved to obtain ternary material powder. 10g of the ternary material powder was mixed with 200mL of 0.5mol / L phytic acid solution; the mixture was heated to 80℃, and 5mL of 200g / L sodium thiosulfate solution and 1.1mL of 27% hydrogen peroxide were added. The mixture was stirred at a constant temperature for 40min; solid-liquid separation was performed to obtain a leachate containing metal ions. The concentrations of Li, Co, Ni, and Mn in the leachate were analyzed by ICP-OES to calculate the leaching rate.

[0087] Example 4 The ternary cathode material from waste lithium batteries was disassembled, peeled, and sieved to obtain ternary material powder. 20g of the ternary material powder was mixed with 200mL of 0.5mol / L phytic acid solution; the mixture was heated to 80℃, and 2.2ml of 27% hydrogen peroxide was added, followed by constant-temperature stirring for 40min; solid-liquid separation was performed to obtain a leachate containing metal ions. The concentrations of Li, Co, Ni, and Mn in the leachate were analyzed by ICP-OES to calculate the leaching rate.

[0088] Example 5 The ternary cathode material from waste lithium batteries was disassembled, peeled, and sieved to obtain ternary material powder. 20g of the ternary material powder was mixed with 200mL of 0.5mol / L phytic acid solution; the mixture was heated to 80℃, and 10mL of 200g / L sodium thiosulfate solution was added, followed by constant-temperature stirring for 40min; solid-liquid separation was performed to obtain a leachate containing metal ions. The concentrations of Li, Co, Ni, and Mn in the leachate were analyzed by ICP-OES to calculate the leaching rate.

[0089] Example 6 The ternary cathode material from waste lithium batteries was disassembled, peeled, and sieved to obtain ternary material powder. 10g of the ternary material powder was mixed with 200mL of 1mol / L phytic acid solution; the mixture was heated to 80℃, and 2.2ml of 27% hydrogen peroxide was added, followed by constant-temperature stirring for 40min; solid-liquid separation was performed to obtain a leachate containing metal ions. The concentrations of Li, Co, Ni, and Mn in the leachate were analyzed by ICP-OES to calculate the leaching rate.

[0090] Example 7 The ternary cathode material from waste lithium batteries was disassembled, peeled, and sieved to obtain ternary material powder. 10g of the ternary material powder was mixed with 200mL of 1mol / L phytic acid solution; the mixture was heated to 80℃, and 10mL of 200g / L sodium thiosulfate solution was added, followed by constant-temperature stirring for 40min; solid-liquid separation was performed to obtain a leachate containing metal ions. The concentrations of Li, Co, Ni, and Mn in the leachate were analyzed by ICP-OES to calculate the leaching rate.

[0091] Example 8 The ternary cathode material from spent lithium batteries was disassembled, peeled, and sieved to obtain ternary material powder. 10g of the ternary material powder was mixed with 200mL of 0.5mol / L phytic acid solution; the mixture was heated to 80℃, and 4.4ml of 27% hydrogen peroxide was added, followed by constant-temperature stirring for 40min; solid-liquid separation was performed to obtain a leachate containing metal ions. The concentrations of Li, Co, Ni, and Mn in the leachate were analyzed by ICP-OES to calculate the leaching rate.

[0092] Example 9 The ternary cathode material from waste lithium batteries was disassembled, peeled, and sieved to obtain ternary material powder. 10g of the ternary material powder was mixed with 200mL of 0.5mol / L phytic acid solution; the mixture was heated to 80℃, and 20mL of 200g / L sodium thiosulfate was added, followed by constant-temperature stirring for 40min; solid-liquid separation was performed to obtain a leachate containing metal ions. The concentrations of Li, Co, Ni, and Mn in the leachate were analyzed by ICP-OES to calculate the leaching rate.

[0093] Example 10 The ternary cathode material from waste lithium batteries was disassembled, peeled, and sieved to obtain ternary material powder. 10g of the ternary material powder was mixed with 200mL of 0.5mol / L phytic acid solution; the mixture was heated to 100℃, and 10mL of 200g / L sodium thiosulfate was added, followed by constant-temperature stirring for 40min; solid-liquid separation was performed to obtain a leachate containing metal ions. The concentrations of Li, Co, Ni, and Mn in the leachate were analyzed by ICP-OES to calculate the leaching rate.

[0094] Example 11 The ternary cathode material from waste lithium batteries was disassembled, peeled, and sieved to obtain ternary material powder. 10g of the ternary material powder was mixed with 200mL of 0.5mol / L phytic acid solution; the mixture was heated to 80℃, and 2.2ml of 27% hydrogen peroxide was added, followed by constant-temperature stirring for 90min; solid-liquid separation was performed to obtain a leachate containing metal ions. The concentrations of Li, Co, Ni, and Mn in the leachate were analyzed by ICP-OES to calculate the leaching rate.

[0095] Comparative Example 1 The ternary cathode material from waste lithium batteries was disassembled, peeled, and sieved to obtain ternary material powder. 10g of the ternary material powder was mixed with 200mL of 0.5mol / L phytic acid solution; the mixture was heated to 80℃ without adding a reducing agent; solid-liquid separation was performed to obtain a leachate containing metal ions. The concentrations of Li, Co, Ni, and Mn in the leachate were analyzed by ICP-OES to calculate the leaching rate.

[0096] Comparative Example 2 The ternary cathode material from spent lithium batteries was disassembled, peeled, and sieved to obtain ternary material powder. 10g of the ternary material powder was mixed with 200mL of 0.5mol / L phytic acid solution; the mixture was heated to 120℃, and 2.2ml of 27% hydrogen peroxide was added for constant-temperature stirring. Solid-liquid separation was performed to obtain a leachate containing metal ions. The concentrations of Li, Co, Ni, and Mn in the leachate were analyzed by ICP-OES to calculate the leaching rate.

[0097] Comparative Example 3 The ternary cathode material from waste lithium batteries was disassembled, peeled, and sieved to obtain ternary material powder. 10g of the ternary material powder was mixed with 200mL of 2mol / L phytic acid solution; the mixture was heated to 80℃, and 10mL of 200g / L sodium thiosulfate was added for constant-temperature stirring; solid-liquid separation was performed to obtain a leachate containing metal ions. The concentrations of Li, Co, Ni, and Mn in the leachate were analyzed by ICP-OES to calculate the leaching rate.

[0098] Comparative Example 4 The ternary cathode material from spent lithium batteries was disassembled, peeled, and sieved to obtain ternary material powder. 10g of the ternary material powder was mixed with 200mL of 0.5mol / L phytic acid solution; the mixture was heated to 28℃, and 2.2ml of 27% hydrogen peroxide was added, followed by constant-temperature stirring for 40min; solid-liquid separation was performed to obtain a leachate containing metal ions. The concentrations of Li, Co, Ni, and Mn in the leachate were analyzed by ICP-OES to calculate the leaching rate.

[0099] The leaching rates of Li, Co, Ni, and Mn in the examples and comparative examples were calculated, and the results are shown in Table 1 below: Table 1. Leaching rates of Li, Mn, Co, and Ni in ternary cathode materials from waste lithium batteries.

[0100]

[0101] As can be seen, the recycling method for ternary cathode materials in waste lithium batteries provided in this application embodiment can achieve high leaching rates of Li, Mn, Co, and Ni, with leaching rates of Li, Ni, Co, and Mn all reaching over 98%.

Claims

1. A method for recycling ternary cathode materials from waste lithium batteries, characterized in that, The method includes: The ternary cathode sheet of waste lithium-ion batteries is processed to obtain ternary material powder; The ternary material powder is mixed with phytic acid solution, heated to a preset temperature, and a reducing agent is added for constant temperature stirring reaction; Solid-liquid separation yields a leachate containing metal ions.

2. The method for recycling ternary cathode materials from waste lithium batteries as described in claim 1, characterized in that, The reducing agent includes hydrogen peroxide and / or sodium thiosulfate.

3. The method for recycling ternary cathode materials from spent lithium batteries as described in claim 2, characterized in that, The mass fraction of the hydrogen peroxide is 26%~33%; And / or, the concentration of the sodium thiosulfate is 50 g / L to 300 g / L.

4. The method for recycling ternary cathode materials from spent lithium batteries as described in claim 1, characterized in that, The concentration of the phytic acid solution is 0.1 mol / L to 1.5 mol / L.

5. The method for recycling ternary cathode materials from spent lithium batteries as described in claim 1, characterized in that, The solid-liquid ratio of the ternary material to the phytic acid solution is 50 g / L to 500 g / L.

6. The method for recycling ternary cathode materials from spent lithium batteries as described in claim 1, characterized in that, The reaction time for the constant temperature stirring reaction is 30 min to 120 min; And / or, the preset temperature is 30℃~100℃.

7. The method for recycling ternary cathode materials from spent lithium batteries as described in claim 1, characterized in that, The solid-liquid separation method is hot filtration.

8. The method for recycling ternary cathode materials from spent lithium batteries as described in claim 1, characterized in that, The leaching rate of metal ions in the leachate containing Li, Ni, Co and Mn is greater than or equal to 98%.

9. The method for recycling ternary cathode materials from spent lithium batteries as described in claim 1, characterized in that, After the step of obtaining the leachate containing metal ions, the method further includes: The leachate and the first extractant are mixed, and sodium hydroxide is added for saponification to perform the first extraction, thereby obtaining the first aqueous phase. The first extractant includes di(2-ethylhexyl) phosphate and sulfonated kerosene. The first aqueous phase and the second extractant are mixed and a second extraction is performed to obtain a manganese-containing organic phase and a second aqueous phase, wherein the second extractant includes 2-ethylhexyl phosphate mono-2-ethylhexyl ester and sulfonated kerosene. The second aqueous phase and the second extractant are mixed and a third extraction is performed to obtain a cobalt-containing organic phase and a third aqueous phase; The third aqueous phase and the second extractant are mixed and a fourth extraction is performed to obtain a nickel-containing organic phase and a fourth aqueous phase; Sodium carbonate was added to the fourth aqueous phase to obtain lithium carbonate.

10. The method for recycling ternary cathode materials from spent lithium batteries as described in claim 9, characterized in that, During the first extraction process, the pH of the leachate is adjusted to 2-4; And / or, during the second extraction process, the pH of the first aqueous phase is adjusted to 3~3.5; And / or, during the third extraction process, the pH of the second aqueous phase is adjusted to 4.5~5; And / or, during the fourth extraction process, the pH of the third aqueous phase is adjusted to 5.5~6; And / or, after adding sodium carbonate to the fourth aqueous phase, adjust the pH to 10-11.

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