A method for recycling and processing waste ternary battery black powder

Abstract

This invention belongs to the field of waste battery recycling, and specifically relates to a method for recycling and processing black powder from waste ternary lithium batteries. The method includes the following steps: S1 Primary acid washing: Mixing nickel- and cobalt-containing aluminum slag (aluminum slag 1) with sulfuric acid at an initial pH of 4-5; S2 Solid-liquid separation I: Separating the mixture obtained in S1 into a filtrate rich in nickel sulfate and cobalt sulfate, and aluminum slag 2; S3 Back-conditioning of filtrate 1; S4 Precipitation and recovery of aluminum slag 2. The technical solution of this invention achieves efficient recovery of valuable metals and deep purification of impurity metals, solving the technical bottleneck of traditional hydrometallurgical processes where these two aspects are difficult to balance. This invention elevates a traditional wastewater and waste residue treatment process into an advanced process system that achieves efficient resource conversion, internal recycling synergy, and a win-win situation for both economic and environmental benefits. It has significant application value in the field of non-ferrous metal resource recycling, especially in the field of lithium-ion battery recycling.

Description

Technical Field

[0001] This invention belongs to the field of waste battery recycling, and specifically relates to a method for recycling and processing black powder from waste ternary lithium batteries. Background Technology

[0002] With the rapid development of new energy, electronics, and high-end equipment manufacturing industries, the market demand for nickel and cobalt, as key strategic metals, continues to surge. During their smelting, processing, and recycling, large quantities of nickel- and cobalt-rich waste slag and waste liquid are generated, often accompanied by high levels of impurities such as aluminum. If these aluminum slag and nickel- and cobalt-containing waste liquids are not treated efficiently and environmentally and recycled, it will not only waste valuable nickel and cobalt metal resources but may also pose a serious threat to the environment due to the leaching of harmful components. This has become a key technical challenge restricting the green and sustainable development of related industries.

[0003] Currently, the commonly used technology in the industry for treating such metal-containing waste is the neutralization method. This method mainly adjusts the pH value of the material by adding alkaline substances, causing metal ions such as aluminum, nickel, and cobalt to precipitate out as hydroxides. However, this method has significant limitations. First, the precipitation conditions for nickel, cobalt, and aluminum hydroxides are similar, resulting in complex precipitate composition and forming a mixed waste residue that is difficult to separate, leading to low recovery rates of valuable metals such as nickel and cobalt. Second, advanced processes for separating and purifying nickel and cobalt using extraction methods generate large amounts of waste hydrochloric acid, which traditionally lacks effective utilization methods. Direct disposal as hazardous waste increases costs and poses environmental risks. Furthermore, the entire process relies on purchased alkaline reagents to repeatedly adjust the pH, increasing raw material costs and generating more solid waste, thus increasing the difficulty and cost of subsequent treatment. Particularly noteworthy is the poor separation effect of existing technologies on impurity aluminum, failing to achieve its high-value utilization. It is usually disposed of as hazardous waste in landfills, which is undoubtedly a secondary waste of resources and a potential burden on the environment.

[0004] In summary, existing technologies generally suffer from a series of drawbacks, such as low nickel and cobalt recovery rates, waste of waste acid resources, high processing costs, and difficulties in separating and recycling aluminum impurities. There is an urgent need to develop a new process that can synergistically recover valuable metals, realize the recycling of waste resources, and is environmentally friendly and cost-effective.

[0005] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the inventors studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0006] This invention belongs to the field of waste battery recycling, and specifically relates to a method for recycling and processing black powder from waste ternary lithium batteries.

[0007] To address the aforementioned technical problems, one objective of this invention is to provide a method for recycling and processing black powder from waste ternary lithium batteries, comprising the following steps: S1 First pickling: Mix nickel- and cobalt-containing aluminum slag (aluminum slag 1) with sulfuric acid with an initial pH of 4-5 and pickle to reduce the pH of the system to 2-3; S2 Solid-liquid separation I: The mixture obtained in S1 is subjected to solid-liquid separation to obtain filtrate 1 rich in nickel sulfate and cobalt sulfate and aluminum slag 2; S3 Filtrate 1 back adjustment: Mix aluminum slag 2 and sodium carbonate obtained from S2 with filtrate 1 to adjust the pH of the mixture to 4-5, and then filter to separate them to obtain aluminum slag 3 and filtrate 2; S4 Aluminum Slag 2 Precipitation Recovery: Add an acid regulator to aluminum slag 2 to adjust the pH to 1.0-2.5, and then add a sulfiding agent to precipitate and separate nickel cobalt sulfide and aluminum chloride solution.

[0008] According to a preferred embodiment, aluminum slag 1 is aluminum slag generated during the recovery of valuable metals from ternary battery black powder.

[0009] According to a preferred embodiment, the recovery of valuable metals from ternary battery black powder includes the following steps: leaching: using sulfuric acid to control the pH of the solution to 1.5-3.0 and then filtering to obtain filtrate; iron removal: adding an oxidant to the filtrate to oxidize ferrous iron, then adding sodium carbonate solution to adjust the pH of the solution to 3.0 and filtering again; aluminum removal: adding sodium carbonate solution to the filtrate to adjust the pH to 4.0-5.0, and the filter cake after filtration is aluminum slag 1.

[0010] According to a preferred embodiment, in S1, the reaction temperature is 40-60 °C.

[0011] According to a preferred embodiment, in S1, aluminum slag 1 is mixed with water, slurried for 1-2 hours, and then subjected to a single acid wash.

[0012] According to a preferred embodiment, in step S4, the acid regulator is selected from the extraction waste hydrochloric acid. The acidity of the extraction waste hydrochloric acid is 4-8 N.

[0013] According to a preferred embodiment, the vulcanizing agent is selected from sodium sulfide.

[0014] According to a preferred embodiment, the liquid-solid ratio of aluminum slag 2 to filtrate 1 is 3-5:1, in units of L / kg.

[0015] According to a preferred embodiment, the precipitation separation includes the following steps: adding sodium sulfide to the nickel-cobalt liquid obtained by dissolving aluminum slag 2, maintaining the temperature at 60-80°C, and reacting for 1-2 hours.

[0016] According to a preferred embodiment, in step S4, an acid regulator extracts waste hydrochloric acid. The waste hydrochloric acid is mainly generated due to the deep purification of organic matter during the extraction process. Hydrochloric acid is used to back-extract impurities from the organic matter, and the back-extraction solution is the extracted waste hydrochloric acid.

[0017] According to a preferred embodiment, in S2, the solid-liquid separation method includes pressure filtration or centrifugation.

[0018] According to a preferred embodiment, in S3, the filtration separation method includes pressure filtration or centrifugation.

[0019] One of the objectives of this invention is to provide the application of the above-mentioned recycling method for waste ternary lithium battery black powder in the treatment of aluminum dross generated during the recovery of valuable metals from ternary lithium battery black powder.

[0020] The beneficial effects of this technical solution are: The technical solution of this invention achieves efficient recovery of valuable metals and deep purification of impurity metals, overcoming the technical bottleneck of traditional hydrometallurgical processes where these two aspects are difficult to achieve simultaneously. By employing a synergistic process combining "aluminum slag acid washing" and "combined pH adjustment," the recovery rate of valuable metals such as nickel and cobalt is significantly improved. Experimental data clearly show that, under optimal conditions, the washing rates of both nickel and cobalt exceed 90%, achieving the ultimate recovery of precious resources. Crucially, in the key step of deep aluminum removal, the use of a combined pH adjustment method of "aluminum slag-sodium carbonate" not only reduces the concentration of aluminum impurities in the solution to a lower level (e.g., from 6.77 g / L to 0.81 g / L) compared to using sodium carbonate (soda ash) alone, while consuming the same amount of alkali, thus ensuring the quality of feed materials for subsequent processes, but also significantly reduces the co-precipitation loss of valuable metals such as nickel and cobalt during the impurity removal process. This ability to ensure high recovery rates while achieving efficient impurity removal is the core innovation of this solution, distinguishing it from traditional precipitation methods, and directly translates into considerable economic value.

[0021] Meanwhile, this solution establishes an internal material recycling system, achieving true "waste-to-waste treatment," resulting in significant cost savings and environmental benefits. The process innovatively utilizes waste hydrochloric acid generated during the extraction process for pickling aluminum slag, both absorbing the difficult-to-treat waste acid and replacing the use of fresh acid, significantly reducing raw material procurement costs and hazardous waste disposal expenses. Simultaneously, the aluminum slag itself is transformed from untreated solid waste into a "process reagent" with alkaline and metal buffering functions, used to replace some commercial alkali for pH adjustment. This not only further reduces reagent costs but also allows valuable metals entrained in the aluminum slag to re-enter the system for recovery. This design, which uses upstream and downstream waste as raw materials, forms a closed-loop material flow, greatly reducing the overall system's material consumption and waste emissions, conforming to the principles of green chemistry and circular economy, and demonstrating strong environmental friendliness.

[0022] Furthermore, through optimization and integration, multiple unit operations such as impurity removal, recovery, and pH adjustment are organically combined, simplifying the process flow and reducing equipment investment and operational complexity. Optimal reaction conditions (e.g., temperature, pH range, reaction time) established based on clear experimental data provide a stable and reliable operating window for industrial production, ensuring consistent product quality. Ultimately, this approach not only produces a pure nickel-cobalt-manganese sulfate solution as the main product, which can be directly used to prepare high-end battery materials, but also converts the removed aluminum impurities into a marketable water purification agent, achieving high-value utilization of waste, forming a diversified product structure, and enhancing the project's resilience and profitability.

[0023] In summary, this invention elevates a traditional wastewater and waste residue treatment process into an advanced process system that achieves efficient resource conversion, internal recycling synergy, and a win-win situation for both economic and environmental benefits. It has significant application value in the field of non-ferrous metal resource recycling, especially in the field of lithium-ion battery recycling. Attached Figure Description

[0024] Figure 1 This is a process flow diagram of the present invention; Figure 2 This is a flow chart of the aluminum slag treatment process of the present invention. Detailed Implementation

[0025] In the description of this invention, terminology is used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0026] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the materials, reagents or instruments used, unless otherwise specified by the manufacturer, are all commercially available reagents and materials; the conditions not specified in the examples are all carried out according to conventional conditions or conditions recommended by the manufacturer. At the same time, the present invention does not limit the source of the raw materials used. Unless otherwise specified, the raw materials used in the present invention are all commercially available products in this technical field.

[0027] Example 1 This embodiment relates to a method for recycling and processing waste ternary lithium battery black powder, and more particularly to a method for recovering nickel, cobalt and aluminum from aluminum slag generated when recovering valuable metals from ternary lithium battery black powder.

[0028] The composition of the aluminum slag in this embodiment was detected by inductively coupled plasma (ICP) method, as shown in Table 1 below.

[0029] Table 1

[0030] Wash the aluminum dross 1 with the composition of Table 1 above according to the following steps.

[0031] First pickling: Add 600 mL of tap water to 200 g of nickel- and cobalt-containing aluminum slag (aluminum slag 1) with an initial pH of 4-5, slurry for 1 h, pickle, and then add concentrated sulfuric acid dropwise to maintain the washing acidity at pH 2.5. The reaction temperature is 50℃.

[0032] Solid-liquid separation I: The mixture obtained in S1 is subjected to solid-liquid separation by pressure filtration. The pressure filtration parameters are 18 MPa and filtration time is 1 h to obtain filtrate 1 rich in nickel sulfate and cobalt sulfate and aluminum slag 2. Filtrate 1 back adjustment: Mix the obtained aluminum slag 2 with filtrate 1 to adjust the pH of the mixture to 4-5, and then filter and separate by centrifugation at 2400 rpm for 0.5 h to obtain aluminum slag 3 and filtrate 2. Aluminum slag 2 precipitation recovery: Add an acid regulator to aluminum slag 2 to adjust the pH to 1.0-2.5, then add a sulfiding agent (sodium sulfide) until precipitation occurs, and separate nickel cobalt sulfide and aluminum chloride solution.

[0033] Table 2 shows the test results after a single pickling under different conditions.

[0034] Table 2

[0035] Example 2 A nickel sulfate solution was prepared with Ni = 13 g / L, Co = 1.24 g / L, Al = 6.77 g / L, and pH = 2.5. 400 mL of the nickel sulfate solution was used to investigate the effects of pH adjustment with sodium carbonate solution (140 g / L), pH adjustment with aluminum slag 1, and pH adjustment using a combination of aluminum slag 1 and sodium carbonate solution (140 g / L) on the solution system. The reaction temperature was 80℃, and the stirring speed was 200 rpm.

[0036] Table 3

[0037] According to the results in Table 3, using only aluminum slag 1 to adjust the pH can achieve a pH of around 3.0. Using only sodium carbonate solution to adjust the pH to 4.0-4.5 allows for the removal of aluminum up to 3.3 g / L. Using a combined method to adjust the pH, with the same amount of sodium carbonate consumed, results in greater nickel and cobalt recovery and cleaner aluminum removal, allowing for direct reuse.

[0038] It should be noted that the specific embodiments described above are exemplary, and those skilled in the art can devise various solutions inspired by the disclosure of this invention. These solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification and its accompanying drawings are illustrative and not intended to limit the scope of the claims. The scope of protection of this invention is defined by the claims and their equivalents.

Claims

1. A method for recycling and processing waste ternary battery black powder, characterized in that, Includes the following steps: S1 First pickling: Mix aluminum slag 1 containing nickel and cobalt with sulfuric acid with an initial pH of 4-5 and pickle to reduce the pH of the system to 2-3; S2 Solid-liquid separation I: The mixture obtained in S1 is subjected to solid-liquid separation to obtain filtrate 1 rich in nickel sulfate and cobalt sulfate and aluminum slag 2; S3 Filtrate 1 back adjustment: Mix aluminum slag 2 and sodium carbonate obtained from S2 with filtrate 1 to adjust the pH of the mixture to 4-5, and then filter to separate them to obtain aluminum slag 3 and filtrate 2; S4 Aluminum Slag 2 Precipitation Recovery: Add an acid regulator to aluminum slag 2 to adjust the pH to 1.0-2.5, and then add a sulfiding agent to precipitate and separate nickel cobalt sulfide and aluminum chloride solution.

2. The method of claim 1, wherein, The preparation method of aluminum slag 1 includes the following steps: After the black powder from waste ternary batteries is leached, an oxidant is added to the leachate to oxidize ferrous iron. Then the pH is adjusted to 3.0, and the iron is removed by filtration. The filtrate without iron is further adjusted to pH 4-5. The filter cake after filtration is aluminum slag 1.

3. The method of claim 1, wherein, In S1, the reaction temperature is 40-60℃.

4. The method of claim 1, wherein, In S1, aluminum slag 1 is mixed with tap water, pulped for 1-2 hours, and then subjected to a pickling process.

5. The method of claim 1, wherein, In S2, the solid-liquid separation method can be pressure filtration or centrifugation.

6. The method of claim 1, wherein, In S3, aluminum slag 2 obtained from S2 is mixed with 140 g / L sodium carbonate.

7. The method according to claim 1, characterized in that, In S4, the acid regulator is selected from extraction waste hydrochloric acid with an acidity of 4-8 N.

8. The method according to claim 1, characterized in that, In S4, the sulfiding agent is selected from sodium sulfide.

9. The method according to claim 1, characterized in that, In S4, the precipitation separation includes the following steps: adding sodium sulfide to the nickel-cobalt liquid obtained by dissolving aluminum slag 2, maintaining the temperature at 60-80℃, and reacting for 1-2 hours.

10. The application of the recycling and treatment method of waste ternary battery black powder according to any one of claims 1-9 in the treatment of aluminum dross generated when recovering valuable metals from ternary battery black powder.

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