Treatment method of waste ternary lithium ion battery black powder

Abstract

The invention relates to a waste ternary lithium ion battery black powder treatment method which comprises the following steps: in the presence of a reducing agent, carrying out acid leaching on waste ternary lithium ion battery black powder to be treated to obtain a leaching system; mixing the leaching system with iron powder, and reacting to obtain copper-removed ore pulp; and waste ternary lithium ion battery black powder is added into the copper removal ore pulp, the pH value of a reaction system is made to be 4-6, solid-liquid separation is carried out after reaction, and liquid with iron and aluminum removed and black powder filter residues are obtained. According to the treatment method, the technological process is short, production equipment can be simplified, the treatment cost is reduced, meanwhile, the recovery efficiency of valuable metal such as nickel, cobalt, manganese and lithium is effectively improved, the recycling value of black powder treatment is improved, and remarkable technical and economic advantages are achieved.

Description

Technical Field

[0001] The invention relates to a method for treating black powder of waste ternary lithium-ion batteries, and belongs to the field of waste ternary lithium-ion battery treatment. Background Art

[0002] Lithium-ion batteries are widely used in the 3C and new energy vehicle sectors, with a typical service life of 5-8 years. With the rapid development of the electric vehicle and energy storage markets, battery usage has increased significantly, and with it, the number of used ternary lithium-ion batteries continues to rise. In recent years, the recycling market for used ternary lithium-ion batteries has continued to expand, and this growth trend is expected to continue in the future. The valuable elements such as lithium, nickel, cobalt, and manganese contained in these batteries have high recycling value, and if not properly handled, they will cause serious environmental pollution. Therefore, the development of efficient and environmentally friendly lithium-ion battery recycling technology, which combines comprehensive resource recovery with environmental protection, is key to building a closed-loop system for the new energy vehicle industry. It is both an important measure to address resource shortages and a crucial path to achieving green development.

[0003] At present, the industrial recycling of waste ternary lithium-ion batteries first needs to go through a pre-treatment physical recycling process such as crushing, disassembly, and screening to initially obtain the waste ternary lithium-ion battery black powder, and then further use processes such as hydrometallurgy to extract and recover the four valuable metals such as lithium, nickel, cobalt, and manganese in the waste ternary lithium-ion battery black powder. Among them, the pretreatment process is usually completed by professional machinery, which is highly efficient but has poor separation effect. Materials such as copper, iron, aluminum, and fluorine contained in the battery are often partially mixed into the black powder in the form of impurities, resulting in copper, iron, aluminum, and fluorine being leached into the leachate during the subsequent wet acid leaching process. Therefore, in order to realize the resource recycling and utilization of lithium, nickel, cobalt, and manganese in the subsequent recycling process, it is necessary to remove impurities such as copper, iron, aluminum, and fluorine contained in the leachate.

[0004] Chinese invention patent application CN118006900A discloses a method for removing impurities from the acidic leachate of used ternary lithium batteries. The method uses hydrazine hydrate to remove copper, carbonate to remove aluminum, and a defluoridating agent to remove fluoride. The entire process involves three filtration stages. After impurity removal, the copper content is ≤10 mg / L, the aluminum content is ≤30 mg / L, and the fluorine content is ≤30 mg / L. The nickel loss rate, cobalt loss rate, and manganese loss rate are ≤0.17%, ≤0.39%, and ≤0.45%, respectively. However, this method has several drawbacks: it does not consider the removal of iron from the leachate; the three-stage filtration process is lengthy; there is a certain amount of loss of nickel, cobalt, and manganese ions; the aluminum and fluoride ion contents of the leachate remain high after impurity removal; and the hydrazine hydrate added during the copper removal process is an explosive organic material with a certain degree of toxicity, significantly limiting its practical application.

[0005] Chinese invention patent application CN115852164A discloses a method for removing impurities from waste lithium battery leachate. The method uses a two-stage process using sulfides or hydroxides to remove copper, followed by soda ash or sodium hydroxide to remove iron and aluminum. The method does not describe the removal of fluorine. The method's shortcomings include a lengthy process flow, the use of numerous materials, and the introduction of new impurities into the leachate, necessitating subsequent additional procedures to remove these impurities. Furthermore, the method neglects the removal of anions such as fluoride, which can affect the recovery and extraction of valuable metals from the purified solution, limiting its application. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a method for treating black powder from waste ternary lithium-ion batteries to achieve sufficient leaching of valuable elements such as nickel, cobalt, and manganese, as well as effective separation and removal of impurities such as copper, iron, and aluminum.

[0007] In order to solve the above technical problems, the technical solutions of the present invention are as follows:

[0008] A method for treating black powder from waste ternary lithium-ion batteries comprises the following steps:

[0009] S1. After reducing and roasting the waste ternary lithium-ion battery black powder to be processed, acid leaching is performed to obtain a leaching system;

[0010] Alternatively, an acidic leaching agent containing a reducing agent is used to acid-leach the waste ternary lithium-ion battery black powder to be treated to obtain a leaching system;

[0011] S2, mixing the leaching system with iron powder, and reacting to obtain copper-removing slurry;

[0012] S3, adding waste ternary lithium-ion battery black powder to the copper-removing slurry to make the pH value of the reaction system 4-6, and after the reaction, separating the solid and liquid to obtain a liquid after iron and aluminum removal and a black powder filter residue;

[0013] Among them, in S3, during the reaction, the pH value of the reaction system is maintained at 4-6 by adding black powder of waste ternary lithium-ion batteries.

[0014] Generally, the leaching system mainly contains ionic nickel, ionic cobalt, ionic manganese and ionic lithium, and also contains various impurity ions such as copper ions, iron ions, ferrous ions, aluminum ions, fluoride ions, etc.

[0015] Furthermore, the waste ternary lithium-ion battery black powder is waste ternary lithium-ion battery black powder that has been subjected to anaerobic pyrolysis. Optionally, the waste ternary lithium-ion battery black powder is waste ternary lithium-ion battery black powder that has been subjected to anaerobic pyrolysis at 300-400° C. for 1-3 hours.

[0016] Optionally, the waste ternary lithium-ion battery black powder includes one or more of lithium nickel cobalt manganese type black powder and nickel cobalt manganese type black powder; wherein, the lithium nickel cobalt manganese type black powder (LNCM) is the waste ternary lithium-ion battery black powder produced by disassembly, crushing and anaerobic pyrolysis, and the nickel cobalt manganese type black powder (NCM) is the waste ternary lithium-ion battery black powder produced by disassembly, crushing, anaerobic pyrolysis and pre-leaching lithium process.

[0017] Optionally, in the waste ternary lithium-ion battery black powder, the content of Li is 0.1-10wt%, the content of Ni is 20-30wt%, the content of Co is 5-15wt%, the content of Mn is 10-20wt%, the content of Al is 0.5-2wt%, the content of Cu is 1-6wt%, the content of Fe is 0.2-2.5wt%, and the content of F is 0.5-5wt%.

[0018] Furthermore, in S1, the waste ternary lithium-ion battery black powder to be treated is mixed with an acidic leaching agent at a liquid-solid ratio of 1g:5-10mL; wherein the H + The concentration is 4-10mol / L.

[0019] Furthermore, the acidic leaching agent includes one or both of an inorganic acid and an organic acid; the inorganic acid includes one or more of sulfuric acid, hydrochloric acid, and nitric acid; and the organic acid includes one or more of citric acid, malic acid, succinic acid, acetic acid, oxalic acid, tartaric acid, and ascorbic acid.

[0020] Furthermore, in S1, the reducing agent includes one or both of an inorganic reducing agent and an organic reducing agent, wherein the inorganic reducing agent includes one or more of hydrogen peroxide, sodium sulfite, sodium bisulfite, and sodium thiosulfate, and the organic reducing agent includes one or more of ascorbic acid, tartaric acid, glucose, and starch; preferably, the reducing agent is hydrogen peroxide with a concentration of 20-30wt%, and the concentration of the reducing agent in the acidic leaching agent is 5-10vol%.

[0021] Furthermore, in S1, acid leaching is carried out at 50-95° C. for 1-2 hours at a stirring speed of 30-150 r / min.

[0022] Furthermore, in S2, the amount of iron powder added is 1.2-1.5 times the theoretical amount of iron powder required for copper removal (i.e., the amount of iron powder required to reduce all the ionic copper in the leaching system to elemental copper). Preferably, the reaction is carried out at 25-75° C. for 1-2 h at a stirring speed of 20-150 r / min.

[0023] Furthermore, in S3, the reaction is carried out at 40-90° C. for 2-3 h at a stirring speed of 100-500 r / min.

[0024] Optionally, in S3, the filtering equipment used for solid-liquid separation is a filter press loaded with diatomaceous earth. Preferably, the filter press is any one of a plate and frame filter press, a chamber filter press, a vertical filter press, a belt filter press, and a diaphragm filter press.

[0025] Furthermore, the acid leaching process of S1, the reaction process of S2, and the reaction process of S3 are all carried out in the same reactor. Preferably, the reactor is a stirred tank, and more preferably, the reactor is any one of a cylindrical stirred tank, a square stirred tank, and a conical stirred tank. Thus, the leaching and impurity removal processes are completed in the same reactor, which can effectively reduce the number of equipment and also reduce the energy consumption and loss required for transporting materials between different functional units.

[0026] Furthermore, after S3, the step of removing fluorine from the de-ironized and de-aluminized liquid is further included, namely, mixing the de-ironized and de-aluminized liquid with a de-fluorinating agent at a liquid-solid ratio of 1 L: 40-100 g, reacting, and separating the solid and liquid to obtain a purified liquid;

[0027] Preferably, the reaction is carried out at a stirring speed of 50-90 r / min at 30-70° C. for 1-2 h;

[0028] Preferably, the defluorination agent comprises one or more of activated alumina, rare earth adsorbent, and rare earth modified adsorbent, preferably activated alumina. The fluorine-containing defluorination agent after defluorination can be recycled through a regeneration process.

[0029] Optionally, in the purified liquid, the copper content is ≤5 mg / L, the iron content is ≤5 mg / L, the aluminum content is ≤10 mg / L, and the fluorine content is ≤5 mg / L.

[0030] Preferably, the black powder residue is returned to S1 for acid leaching.

[0031] Preferably, in the purified liquid, the final contents of nickel, cobalt, manganese and lithium are increased and replenished, wherein the replenishment rate of nickel is ≤0.50%, the replenishment rate of cobalt is ≤0.50%, the replenishment rate of manganese is ≤0.50%, and the replenishment rate of lithium is ≤40%.

[0032] The purified liquid can be used to recover mother liquors of nickel, cobalt, manganese and lithium, and to prepare materials or products containing nickel, cobalt, manganese and lithium for regeneration applications.

[0033] The purified liquid can form a high-purity mother liquor containing valuable elements such as nickel, cobalt, manganese, and lithium, which can be further extracted and applied in related fields, including but not limited to the preparation of ternary lithium-ion battery positive electrode materials or their precursor materials (nickel sulfate, cobalt sulfate, manganese sulfate, lithium carbonate), and other materials containing nickel, cobalt, manganese, and lithium.

[0034] In S2 of the present invention, the iron powder can be reduced to remove the copper ions in the leachate to obtain a copper-removing slurry; in S3, black powder is added to the copper-removing slurry to cause a leaching reaction again, resulting in the consumption of hydrogen ions in the leaching system, reducing the acidity of the solution, increasing the pH of the reaction system and controlling it within a certain range, and oxidizing the ferrous ions in the solution to prepare for the precipitation and removal of iron, that is, having both acid adjustment-oxidation-leaching effects, and ultimately removing the iron and aluminum impurity ions in the leached mixed solution in the form of colloidal slag, and then performing solid-liquid separation. The copper slag, iron-aluminum slag generated in S2 and S3 can be separated from the leachate in one step, while the total amount of slag treatment does not increase, and the number of filtering equipment, processes and labor quotas are also reduced, further improving work efficiency and minimizing processing costs. At the same time, the amount of filter residue is significantly increased, effectively enriching copper, aluminum, and iron impurities in the black powder filter residue, making it easier to achieve full element recovery. In addition, after the reactions of S1-S3 are completed, filtration is performed, and the filterability of the residue in the reaction system is better, which can effectively solve the problem of the colloidal residue generated in S3 being difficult to filter, and help improve the filtration efficiency and effect. In S3, black powder is added without introducing new impurities, and the impurity removal process simultaneously realizes the leaching of nickel, cobalt, manganese, and lithium in the newly added black powder, thereby increasing the content of nickel, cobalt, manganese, and lithium in the solution, making up for the part of nickel, cobalt, manganese, and lithium carried by the black powder filter residue, so that the concentration of nickel, cobalt, manganese, and lithium in the purified liquid not only does not decrease significantly, but the relevant concentration increases, which helps the subsequent processes to proceed more smoothly. The black powder filter residue after impurity removal can be returned to the leaching process after washing and drying. Since part of the nickel, cobalt, manganese, and lithium in the black powder has been leached during the iron and aluminum removal process, the amount of acidic leaching agent can be reduced, further reducing the recovery cost, and realizing the "double synergistic effect" of "black powder leaching method to regulate the acidity of the solution to remove impurities iron and aluminum". The overall recovery rate and recovery efficiency are significantly improved compared with other methods, and the process adaptability is better. In addition, the black powder filter residue can be graded and its composition tested. A portion of the black powder filter residue with a high content of valuable elements can be returned to the leaching process after washing and filtration to continue recovering the remaining nickel, cobalt, manganese and lithium. From the overall process perspective, the loss rate of its valuable elements is zero; the remaining black powder filter residue with a low content of valuable elements is sold to related companies for resource utilization, such as in the field of brick making and other building materials.

[0035] The present invention first dissolves valuable metals such as nickel, cobalt, and manganese through an acidic leaching process, then selectively removes copper ions through a replacement reaction. Spent ternary lithium-ion battery black powder is then added to the leaching system as a neutralizer to control the pH. Impurities such as iron and aluminum are simultaneously removed through a synergistic oxidation-hydrolysis precipitation process. Solid-liquid separation is then performed to obtain a post-iron and aluminum-removed liquid with a low metal impurity content. Fluorination is then removed from the post-iron and aluminum-removed liquid to obtain a purified liquid that meets the requirements for valuable metal recovery. The black powder filter residue can be returned to the front end for further processing or sold directly.

[0036] In view of the limitations of the existing process, the treatment method of the present invention preferentially removes copper ions in the liquid phase of the leaching system through an iron powder replacement reaction, and then introduces black powder to construct a dual synergistic mechanism: on the one hand, the oxides of nickel, cobalt, manganese (lithium), etc. in the black powder are used to neutralize and consume the acid in the solution during the reaction of S3, thereby regulating the pH value of the system, and further, the iron and aluminum ions are hydrolyzed to form a colloidal precipitate; on the other hand, the residual active substances in the black powder continue to release valuable elements such as nickel, cobalt, manganese, and lithium under oxidizing conditions, synchronously achieving impurity removal and valuable metal compensation effects; on the other hand, black powder can oxidize ferrous ions in the liquid phase, laying the foundation for precipitation and removal of iron. The synchronous separation of copper, iron, and aluminum multi-metal slag can be completed by a single filtration, significantly improving the solid-liquid separation efficiency. The present invention has at least the following innovative features: 1. Constructing an internal circulation system that "treats waste with waste," the black powder added to S3 serves as both a pH regulator and oxidant, as well as a secondary leaching raw material, preventing the introduction of new impurities by exogenous reagents; 2. Forming an acidity self-balancing mechanism, where the alkaline substances produced by the dissolution of the black powder couple with the acidic environment of the leachate to achieve a dynamic balance between iron and aluminum removal and valuable metal leaching; 3. Establishing a full-element resource recovery pathway, where the black powder filter residue enriched in copper, iron, and aluminum can be graded and high-value components can be returned to the leaching process to achieve zero loss, while low-grade components can be targeted for resource utilization. Through material recycling and energy cascade utilization, the present invention can reduce leaching agent consumption while ensuring the recovery rates of nickel, cobalt, manganese, and lithium, making the metallurgical process more environmentally friendly.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] (1) The treatment method of the present invention has a short process flow, which helps simplify production equipment. While reducing treatment costs, it effectively improves the recovery efficiency of valuable metals such as nickel, cobalt, manganese, and lithium, and enhances the resource value of black powder treatment, thus possessing significant technical and economic advantages. In addition, the present invention can significantly reduce the number of equipment required for the three steps of leaching, impurity removal, and filtration, and shorten the impurity removal process flow, which helps further improve economic benefits.

[0039] (2) The treatment method of the present invention can achieve efficient separation and removal of impurity elements in the leaching system, and is conducive to the full factor recovery, extraction and utilization of valuable elements in black powder.

[0040] (3) The entire impurity removal process of the present invention is efficient, green and sustainable, which helps to further reduce recycling costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The present invention is a flowchart of a treatment process for waste ternary lithium-ion battery black powder. DETAILED DESCRIPTION

[0042] The present invention will be described in detail below with reference to the embodiments. It should be noted that, unless otherwise specified, the embodiments and features of the embodiments of the present invention may be combined with each other. Unless otherwise specified, the relevant percentages of the present invention refer to mass percentages.

[0043] Example 1

[0044] The method for processing black powder from waste ternary lithium-ion batteries in this embodiment is as follows:

[0045] Step 1: 90 g of spent ternary lithium-ion battery black powder (refer to Table 1-1 for its specific composition, hereinafter referred to as "black powder") after anaerobic pyrolysis at 350°C for 2 h was mixed with 540 mL of an acidic leaching agent (liquid-to-solid ratio of 6 mL / g), and leached at 80 r / min and 80°C for 1 h. After the reaction was completed, a leaching system was obtained;

[0046] The acidic leaching agent is formed by mixing a sulfuric acid solution and a reducing agent in a volume ratio of 94:6; the reducing agent is hydrogen peroxide, the concentration of the hydrogen peroxide is 27.5wt%, and the sulfuric acid concentration in the sulfuric acid solution is 4mol / L);

[0047] Step 2: Mix the leaching system with iron powder and react at 120 r / min and 30°C for 1 hour to obtain a copper-removed slurry (solution 1);

[0048] Among them, the amount of iron powder used is 1.2 times the theoretical amount for copper removal;

[0049] Step 3: Add black powder to the copper removal slurry to make the pH value of the reaction system 4.5±0.5, react at 400 r / min and 85°C for 3 hours, and then separate the solid and liquid to obtain black powder residue containing copper, aluminum, and iron and a liquid after iron and aluminum removal (Solution 2);

[0050] Step 4: Mix the iron and aluminum-removed liquid with a defluoridating agent (activated alumina) at a ratio of 1 L: 60 g, react at 60 r / min and 45° C. for 1 h, and then separate the solid and liquid to obtain a purified liquid (solution 3).

[0051] The chemical composition of black powder is shown in Table 1-1, and the contents of various elements in the leaching system, copper-removed slurry, iron- and aluminum-removed liquid, and purified liquid are shown in Table 1-2.

[0052] Table 1-1 Chemical composition of black powder of Example 1

[0053] element Li Ni Co Mn Al Cu Fe F C / its Content (wt%) 5.25 24.96 10.14 14.98 1.58 4.4 1.7 2.5 34.49

[0054] Table 1-2 Composition of each solution of Example 1

[0055]

[0056] In Example 1, the leaching rates of the four valuable elements, nickel, cobalt, manganese, and lithium, were 94.00%, 95.70%, 93.29%, and 98.40%, respectively. In the subsequent impurity removal process, no nickel, cobalt, manganese, or lithium was lost. The purified solution in the final solution 3 had a nickel replenishment rate of 0.26%, a cobalt replenishment rate of 1.21%, a manganese replenishment rate of 0.40%, and a lithium replenishment rate of 3.22%. After impurity removal, the purified solution had a copper impurity content of ≤5 mg / L, an iron impurity content of ≤5 mg / L, an aluminum impurity content of ≤10 mg / L, and a fluorine impurity content of ≤5 mg / L.

[0057] Among them, the leaching rate = element content in the leaching system / element content in the black powder × 100%, the replenishment rate = (element content of the purified liquid - element content in the leaching system) / element content in the leaching system × 100%.

[0058] Example 2

[0059] The method for processing black powder from waste ternary lithium-ion batteries in this embodiment is as follows:

[0060] Step 1: 55g of waste ternary lithium-ion battery black powder (see Table 2-1 for specific composition) was mixed with 550mL of acidic leaching agent (liquid-to-solid ratio of 10mL / g), and leached at 120r / min and 90℃ for 1.5h. After the reaction was completed, a leaching system was obtained;

[0061] The acidic leaching agent is formed by mixing a sulfuric acid solution and a reducing agent in a volume ratio of 95:5; the reducing agent is hydrogen peroxide, the concentration of the hydrogen peroxide is 27.5wt%, and the sulfuric acid concentration in the sulfuric acid solution is 5mol / L);

[0062] Step 2: Mix the leaching system with iron powder and react at 100 r / min and 25°C for 1.5 hours to obtain a copper-removed slurry (solution 1);

[0063] Among them, the amount of iron powder used is 1.3 times the theoretical amount for copper removal;

[0064] Step 3: Add waste ternary lithium-ion battery black powder to the copper-removed slurry to make the pH value of the reaction system 4.5±0.5, react at 350r / min and 80°C for 2h, and then separate the solid and liquid to obtain black powder residue containing copper, aluminum, and iron and a liquid after iron and aluminum removal (Solution 2);

[0065] Step 4: Mix the iron and aluminum-removed liquid with a defluoridating agent (activated alumina) at a ratio of 1 L:50 g, react at 80 r / min and 60° C. for 1.5 h, and then separate the solid and liquid to obtain a purified liquid (solution 3).

[0066] The chemical composition of black powder is shown in Table 2-1. The contents of each element in the leaching system, copper-removed slurry, iron- and aluminum-removed liquid, and purified liquid are shown in Table 2-2.

[0067] Table 2-1 Chemical composition of black powder in Example 2

[0068] element Li Ni Co Mn Al Cu Fe F C / its Black powder (wt%) 5.25 24.96 10.14 14.98 1.58 4.4 1.7 2.5 34.49

[0069] Table 2-2 Composition of each solution of Example 2

[0070]

[0071] In Example 2, the leaching rates of the four valuable elements, nickel, cobalt, manganese, and lithium, were 95.15%, 95.69%, 94.00%, and 99.02%, respectively. In the subsequent impurity removal process, no nickel, cobalt, manganese, or lithium was lost. The final purified solution 3 had a nickel replenishment rate of 0.31%, a cobalt replenishment rate of 0.75%, a manganese replenishment rate of 0.71%, and a lithium replenishment rate of 3.15%. After impurity removal, the purified solution had a copper impurity content of ≤5 mg / L, an iron impurity content of ≤5 mg / L, an aluminum impurity content of ≤10 mg / L, and a fluorine impurity content of ≤5 mg / L.

[0072] Example 3

[0073] The method for processing black powder from waste ternary lithium-ion batteries in this embodiment is as follows:

[0074] Step 1: 110g of waste ternary lithium-ion battery black powder (see Table 3-1 for specific composition) was mixed with 550mL of acidic leaching agent (liquid-to-solid ratio of 5mL / g), and leached at 100r / min and 95℃ for 1h. After the reaction was completed, a leaching system was obtained;

[0075] The acidic leaching agent is formed by mixing a sulfuric acid solution and a reducing agent in a volume ratio of 92:8; the reducing agent is hydrogen peroxide, the concentration of the hydrogen peroxide is 27.5wt%, and the sulfuric acid concentration in the sulfuric acid solution is 4mol / L);

[0076] Step 2: Mix the leaching system with iron powder and react at 110 r / min and 35°C for 2 h to obtain a copper-removed slurry (solution 1);

[0077] Among them, the amount of iron powder used is 1.2 times the theoretical amount for copper removal;

[0078] Step 3: Add waste ternary lithium-ion battery black powder to the copper-removed slurry to make the pH value of the reaction system 6.0±0.5, react at 300 r / min and 85°C for 2 hours, and then separate the solid and liquid to obtain black powder residue containing copper, aluminum, and iron and a liquid after iron and aluminum removal (Solution 2);

[0079] Step 4: Mix the iron and aluminum-removed liquid with a defluoridating agent (activated alumina) at a ratio of 1 L:40 g, react at 50 r / min and 70°C for 2 h, and then separate the solid and liquid to obtain a purified liquid (solution 3).

[0080] The chemical composition of black powder is shown in Table 3-1. The contents of each element in the leaching system, copper-removed slurry, iron- and aluminum-removed liquid, and purified liquid are shown in Table 3-2.

[0081] Table 3-1 Chemical composition of black powder of Example 3

[0082] element Li Ni Co Mn Al Cu Fe F C / its Black powder (wt%) 0.4 25.00 12.5 16.3 1.3 3.0 2.2 1.1 38.2

[0083] Table 3-2 Composition of each solution of Example 3

[0084]

[0086] In Example 3, the leaching rates of the four valuable elements, nickel, cobalt, manganese, and lithium, were 97.20%, 97.50%, 97.77%, and 98.46%, respectively. In the subsequent impurity removal process, no nickel, cobalt, manganese, or lithium was lost. The final purified solution in Solution 3 had a nickel replenishment rate of 0.26%, a cobalt replenishment rate of 0.48%, a manganese replenishment rate of 0.26%, and a lithium replenishment rate of 26.44%. After impurity removal, the impurity copper content in the purified solution was ≤5 mg / L, the impurity iron content was ≤5 mg / L, the impurity aluminum content was ≤10 mg / L, and the impurity fluorine content was ≤5 mg / L.

[0087] Example 4

[0088] The method for processing black powder from waste ternary lithium-ion batteries in this embodiment is as follows:

[0089] Step 1: Mix 70g of waste ternary lithium-ion battery black powder (see Table 4-1 for specific composition) with 560mL of acidic leaching agent (liquid-to-solid ratio is 8mL / g), and leach at 140r / min and 70℃ for 2h. After the reaction is completed, a leaching system is obtained;

[0090] The acidic leaching agent is formed by mixing a sulfuric acid solution and a reducing agent in a volume ratio of 92:8; the reducing agent is hydrogen peroxide, the concentration of the hydrogen peroxide is 27.5wt%, and the sulfuric acid concentration in the sulfuric acid solution is 5mol / L);

[0091] Step 2: Mix the leaching system with iron powder and react at 100 r / min and 45°C for 3 hours to obtain a copper-removed slurry (solution 1);

[0092] Among them, the amount of iron powder used is 1.2 times the theoretical amount for copper removal;

[0093] Step 3: Add waste ternary lithium-ion battery black powder to the copper-removed slurry to make the pH value of the reaction system 5.5±0.5, react at 1000 r / min and 90°C for 2 hours, and then separate the solid and liquid to obtain black powder residue containing copper, aluminum, and iron and a liquid after iron and aluminum removal (Solution 2);

[0094] Step 4: Mix the iron and aluminum-removed liquid with a defluoridating agent (activated alumina) at a ratio of 1 L:40 g, react at 80 r / min and 40° C. for 1.5 h, and then separate the solid and liquid to obtain a purified liquid (solution 3).

[0095] The chemical composition of black powder is shown in Table 4-1. The contents of each element in the leaching system, copper-removed slurry, iron- and aluminum-removed liquid, and purified liquid are shown in Table 4-2.

[0096] Table 4-1 Chemical composition of black powder of Example 4

[0097] element Li Ni Co Mn Al Cu Fe F C / its Black powder (wt%) 0.4 25.00 12.5 16.3 1.3 3.0 2.2 1.1 38.2

[0098] Table 4-2 Composition of each solution of Example 4

[0099]

[0100] In Example 4, the leaching rates of the four valuable elements nickel, cobalt, manganese, and lithium were 96.40%, 96.60%, 96.10%, and 99.43%, respectively. In the subsequent impurity removal process, no nickel, cobalt, manganese, or lithium was lost. The final purified solution in Solution 3 had a nickel replenishment rate of 0.33%, a cobalt replenishment rate of 0.77%, a manganese replenishment rate of 0.55%, and a lithium replenishment rate of 33.93%. After impurity removal, the purified solution had a copper impurity content of ≤5 mg / L, an iron impurity content of ≤5 mg / L, an aluminum impurity content of ≤10 mg / L, and a fluorine impurity content of ≤5 mg / L.

[0101] Comparative Example 1

[0102] Example 1 was repeated, except that in step 3, the pH value of the reaction system was set to 3±0.5.

[0103] The contents of various elements in the leaching system, copper-removed slurry, iron- and aluminum-removed liquid, and purified liquid are shown in Table 5.

[0104] Table 5 Composition of each solution of Comparative Example 1

[0105]

[0106] It can be seen that nickel, cobalt, manganese, and lithium were lost during the impurity removal process, with nickel loss rates of 0.54%, cobalt loss rates of 0.69%, manganese loss rates of 0.76%, and lithium loss rates of 1.61%. After impurity removal, the purified liquid had a copper impurity content of ≤5 mg / L, an iron impurity content of ≤400 mg / L, an aluminum impurity content of ≤200 mg / L, and a fluorine impurity content of ≤90 mg / L.

[0107] It can be seen from Table 5 that, mainly, in step three of comparative example 1 relative to step three of embodiment 1, the addition of black powder is insufficient, the pH value of the solution is ≤4, the contents of nickel, cobalt, manganese and lithium are not replenished, and the aluminum and iron ions cannot be completely hydrolyzed and precipitated to be removed, and ultimately the content of iron and aluminum ions after impurities removal is still relatively high; in step four of comparative example 1 relative to step four of embodiment 1, the pH value of the liquid after iron and aluminum removal is too low, which affects the adsorption activity of the defluoridating agent, resulting in a decrease in the fluorine removal rate. The fluorine content after defluorination is 90 mg / L, which is relatively high; in summary, the impurity content of comparative example 1 is still relatively high after impurities removal, and the impurity removal effect is worse than that of embodiment 1.

[0108] Comparative Example 2

[0109] Example 1 was repeated, except that in step 3, the pH value of the reaction system was set to 7±0.5.

[0110] The contents of various elements in the leaching system, copper-removed slurry, iron- and aluminum-removed liquid, and purified liquid are shown in Table 6.

[0111] Table 6 Composition of each solution of Comparative Example 2

[0112]

[0113] It can be seen that nickel, cobalt, manganese, and lithium were lost during the impurity removal process, with nickel loss rates of 0.36%, cobalt loss rates of 0.40%, manganese loss rates of 1.19%, and lithium loss rates of 1.08%. After impurity removal, the purified liquid had an impurity copper content of ≤5 mg / L, an impurity iron content of ≤500 mg / L, an impurity aluminum content of ≤800 mg / L, and an impurity fluorine content of ≤1000 mg / L.

[0114] It can be seen from Table 6 that, mainly, in step three of comparative example 2 relative to step three of example 1, the black powder is added in excess, the pH value of the solution is greater than 6, and the contents of nickel, cobalt, manganese and lithium are not replenished. The possible reason is that the pH value is too high, and the hydroxides dissolve back after the hydrolysis of aluminum and iron ions, resulting in a secondary increase in the iron and aluminum content in the solution, and ultimately the content of iron and aluminum ions after impurities are still high; in step four of comparative example 2 relative to step four of example 1, the pH value of the liquid after iron and aluminum removal is too high, which affects the adsorption activity of the defluoridating agent, resulting in a decrease in the fluorine removal rate. The fluorine content after defluorination is 940 mg / L, which is relatively high; comprehensive analysis shows that the impurity content is still high after impurities removal, and the impurity removal effect is worse than that of Example 1.

[0115] Comparative Example 3

[0116] The treatment method of waste ternary lithium-ion battery black powder in this comparative example is as follows:

[0117] Step 1: Mix 55g of waste ternary lithium-ion battery black powder (see Table 2-1 for specific composition) with 550mL of acidic leaching agent (liquid-to-solid ratio is 10mL / g), and leach at 120r / min and 80℃ for 3h. After the reaction is completed, a leaching system is obtained;

[0118] The acidic leaching agent is formed by mixing a sulfuric acid solution and a reducing agent in a volume ratio of 96:4; the reducing agent is hydrogen peroxide, the concentration of the hydrogen peroxide is 27.5wt%, and the sulfuric acid concentration in the sulfuric acid solution is 5mol / L);

[0119] Step 2: Mix the leaching system with manganese powder and react at 100 r / min and 25°C for 1.5 hours to obtain a copper-removed slurry (solution 1);

[0120] Among them, the amount of manganese powder used is 1.2 times the theoretical amount for copper removal;

[0121] Step 3: Add manganese carbonate (1 g manganese carbonate per 20 mL of copper removal slurry) and an oxidant (oxygen, flow rate 0.5 L / h) to the copper removal slurry to make the pH value of the reaction system 4.5±0.5, react at 350 r / min and 80°C for 2 h, and then separate the solid and liquid to obtain a black powder residue containing copper, aluminum, and iron and a liquid after iron and aluminum removal (Solution 2);

[0122] Step 4: Mix the iron and aluminum-removed liquid with a defluoridating agent (activated alumina) at a ratio of 1 L:50 g, react at 80 r / min and 60° C. for 1.5 h, and then separate the solid and liquid to obtain a purified liquid (solution 3).

[0123] The chemical composition of the black powder is the same as that in Table 2-1. The contents of each element in the leaching system, copper-removed slurry, iron- and aluminum-removed liquid, and purified liquid are shown in Table 7.

[0124] Table 7 Composition of each solution of Comparative Example 3

[0125]

[0127] During the impurity removal process, nickel, cobalt, and lithium ions were lost, with nickel loss rates of 0.38%, cobalt loss rates of 1.12%, and lithium loss rates of 2.10%. After impurity removal, the purified liquid contained ≤20 mg / L of copper, ≤50 mg / L of iron, ≤40 mg / L of aluminum, and ≤5 mg / L of fluorine.

[0128] It can be seen from Table 7 that, compared with step 2 of Example 2, in step 2 of Comparative Example 3, manganese powder is added when removing copper, and the content of copper ions after impurities removal is higher than that when iron powder is added; compared with step 3 of Example 2, in step 3 of Comparative Example 3, manganese carbonate and an oxidant are added when removing iron and aluminum, and the content of iron and aluminum ions after impurities removal is higher than that when black powder is added to remove iron and aluminum; comprehensive analysis shows that the impurity removal effect of Comparative Example 3 is worse than that of Example 2.

[0129] Comparative Example 4

[0130] The treatment method of waste ternary lithium-ion battery black powder in this comparative example is as follows:

[0131] Step 1: 110g of waste ternary lithium-ion battery black powder (see Table 3-1 for specific composition) was mixed with 550mL of acidic leaching agent (liquid-to-solid ratio of 5mL / g), and leached at 100r / min and 95℃ for 1h. After the reaction was completed, a leaching system was obtained;

[0132] The acidic leaching agent is formed by mixing a sulfuric acid solution and a reducing agent in a volume ratio of 92:8; the reducing agent is hydrogen peroxide, the concentration of the hydrogen peroxide is 27.5wt%, and the sulfuric acid concentration in the sulfuric acid solution is 4mol / L);

[0133] Step 2: Mix the leaching system with iron powder, react at 110 r / min and 35°C for 2 hours, and then separate the solid and liquid to obtain a copper-removed slurry (solution 1);

[0134] Among them, the amount of iron powder used is 1.2 times the theoretical amount for copper removal;

[0135] Step 3: Add waste ternary lithium-ion battery black powder to the copper-removed slurry to make the pH value of the reaction system 6.0±0.5, react at 300 r / min and 85°C for 2 hours, and then separate the solid and liquid to obtain black powder residue containing copper, aluminum, and iron and a liquid after iron and aluminum removal (Solution 2);

[0136] Step 4: Mix the iron and aluminum-removed liquid with a defluoridating agent (activated alumina) at a ratio of 1 L:40 g, react at 50 r / min and 70°C for 2 h, and then separate the solid and liquid to obtain a purified liquid (solution 3).

[0137] The chemical composition of the black powder is the same as that in Table 3-1. The contents of each element in the leaching system, copper removal slurry, iron and aluminum removal liquid, and purified liquid are shown in Table 8.

[0138] Table 8 Composition of each solution of Comparative Example 4

[0139]

[0140] During the impurity removal process, nickel, cobalt, manganese, and lithium were lost: nickel loss rate = 0.21%, cobalt loss rate = 0.71%, manganese loss rate = 0.46%, and lithium loss rate = 8.05%. After impurity removal, the purified liquid had an impurity copper content of ≤ 5 mg / L, an impurity iron content of ≤ 5 mg / L, an impurity aluminum content of ≤ 10 mg / L, and an impurity fluorine content of ≤ 5 mg / L.

[0141] As shown in Table 8, step 2 of Comparative Example 4 adds a filtration process (solid-liquid separation) to step 2 of Example 3 after copper removal. After impurity removal, the loss rates of nickel, cobalt, manganese, and lithium are significantly higher than those of Example 3, reducing the overall recovery rate of valuable elements. The additional process also increases recovery costs. Comprehensive analysis shows that although the removal of copper, iron, aluminum, and fluorine achieves the desired effect, the filter residue removes some valuable elements, preventing the efficient recovery of valuable elements in the black powder, resulting in an overall recovery rate lower than that of Example 3.

[0142] In the above embodiments and comparative examples, the analysis method of the element mass content in the solution is:

[0143] 1. Analysis of metal element content in solution

[0144] The contents of copper, aluminum, iron, nickel, cobalt, manganese and lithium in the solution were analyzed using inductively coupled plasma optical emission spectrometer (ICP-OES).

[0145] 2. Analysis of fluorine content in the leaching system

[0146] The fluoride content in the leaching system was analyzed using ion chromatography (IC) or fluoride ion selective electrode method.

[0147] It should be noted that the above embodiments are intended only to illustrate the technical solutions and features of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above preferred embodiments, those skilled in the art will appreciate that the technical solutions of the present invention may be modified or replaced with equivalents, and such modifications or replacements are within the scope of protection of the present invention.

Claims

1. A method for treating black powder from waste ternary lithium-ion batteries, characterized in that: The steps include: S1. After reducing and roasting the waste ternary lithium-ion battery black powder to be treated, acid leaching is performed to obtain a leaching system; or, using an acidic leaching agent containing a reducing agent, acid leaching is performed to obtain a leaching system; S2, mixing the leaching system with iron powder, and reacting to obtain copper-removing slurry; S3, adding waste ternary lithium-ion battery black powder to the copper-removing slurry to make the pH value of the reaction system 4-6, and after the reaction, separating the solid and liquid to obtain a liquid after iron and aluminum removal and a black powder filter residue; Among them, in S3, during the reaction, the pH value of the reaction system is maintained at 4-6 by adding black powder of waste ternary lithium-ion batteries.

2. The processing method according to claim 1, characterized in that The waste ternary lithium-ion battery black powder is waste ternary lithium-ion battery black powder that has been subjected to anaerobic pyrolysis treatment.

3. The processing method according to claim 1, characterized in that In S1, the waste ternary lithium-ion battery black powder to be treated is mixed with an acidic leaching agent at a liquid-solid ratio of 1g:5-10mL; wherein the H + The concentration is 4-10mol / L.

4. The processing method according to claim 3, characterized in that The acidic leaching agent includes one or both of an inorganic acid and an organic acid; the inorganic acid includes one or more of sulfuric acid, hydrochloric acid, and nitric acid; the organic acid includes one or more of citric acid, malic acid, succinic acid, acetic acid, oxalic acid, tartaric acid, and ascorbic acid.

5. The processing method according to claim 1, characterized in that In S1, the reducing agent includes one or both of an inorganic reducing agent and an organic reducing agent, wherein the inorganic reducing agent includes one or more of hydrogen peroxide, sodium sulfite, sodium bisulfite, and sodium thiosulfate, and the organic reducing agent includes one or more of ascorbic acid, tartaric acid, glucose, and starch; preferably, the reducing agent is hydrogen peroxide with a concentration of 20-30wt%, and the concentration of the reducing agent in the acidic leaching agent is 5-10vol%.

6. The processing method according to any one of claims 1 to 5, characterized in that: In S1, acid leaching is performed at 50-95°C for 1-2 hours at a stirring speed of 30-150 r / min.

7. The processing method according to any one of claims 1 to 5, characterized in that: In S2, the amount of iron powder added is 1.2-1.5 times the theoretical amount of iron powder required for copper removal. Preferably, the reaction is carried out at 25-75° C. for 1-2 hours at a stirring speed of 20-150 r / min.

8. The processing method according to any one of claims 1 to 5, characterized in that: In S3, the reaction is carried out at 40-90° C. for 2-3 h at a stirring speed of 100-500 r / min.

9. The processing method according to any one of claims 1 to 5, characterized in that: The acid leaching process of S1, the reaction process of S2 and the reaction process of S3 are all carried out in the same reactor. Preferably, the reactor is a stirred tank, and more preferably, the reactor is any one of a cylindrical stirred tank, a square stirred tank and a conical stirred tank.

10. The processing method according to any one of claims 1 to 5, characterized in that: After S3, the step of removing fluorine from the de-ironized and de-aluminized liquid is also included, namely, mixing the de-ironized and de-aluminized liquid with a de-fluorinating agent at a liquid-solid ratio of 1 L: 40-100 g, reacting, and separating the solid and liquid to obtain a purified liquid; Preferably, the reaction is carried out at a stirring speed of 50-90 r / min at 30-70° C. for 1-2 h; Preferably, the defluorination agent comprises one or more of activated alumina, rare earth adsorbent, and rare earth modified adsorbent; Preferably, the black powder residue is returned to S1 for acid leaching.

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