Method for recycling valuable metal from ternary lithium battery and recycling waste liquid

Abstract

The invention discloses a method for recycling valuable metal from a ternary lithium battery and recycling waste liquid, and relates to the field of waste lithium battery recycling. Comprising the following steps: A, immersing black powder into alkali liquor, and filtering to obtain filter residues; b, immersing filter residues into a sulfuric acid solution, and dropwise adding a hydrogen peroxide solution until the filter residues are completely dissolved; and C, adjusting the pH value of the leachate, and adding a certain amount of trisodium phosphate to precipitate aluminum phosphate. And D, adding ammonia water into the filtered Al-removed leachate for complexing, gradually dropwise adding into a NaOH solution in a protective atmosphere, and filtering to obtain a nickel-cobalt-manganese coprecipitate and a lithium-rich solution. And E, adding trisodium phosphate into the lithium-rich solution, and filtering to obtain lithium phosphate and sodium sulfate tail liquid. And F, crystallizing the sodium sulfate at low temperature, and merging the tail liquid into the lithium-rich solution. According to the method, the average lithium recovery rate exceeds 93%, the recovery rate of nickel, cobalt and manganese reaches 99.8% or above, follow-up waste liquid is recovered, and maximization of economic benefits and environmental benefits is achieved.

Description

Technical Field

[0001] This invention relates to the field of waste lithium battery recycling, and particularly to a method for recovering valuable metals and recycling waste liquid from ternary lithium batteries. Background Technology

[0002] With the rapid development of the new energy vehicle industry, ternary lithium batteries once dominated the power battery market due to their high energy density. However, the service life of lithium batteries is typically 5-10 years, leading to a full-scale retirement of ternary lithium batteries. The core cathode material of spent ternary lithium batteries contains elements such as lithium, nickel, cobalt, and manganese, with elemental content far exceeding that of primary resources. Proper recycling of spent ternary lithium batteries can alleviate the pressure on raw material supply. Developing green, high-yield, and short-process recycling technologies for spent ternary lithium batteries is currently of paramount importance.

[0003] Currently, there are two main methods for recycling cathode materials in ternary lithium batteries: pyrometallurgy and hydrometallurgy. Pyrometallurgy uses high-temperature smelting to recover valuable metals from the cathode material in the form of oxides. However, pyrometallurgical recycling has disadvantages such as high energy consumption and toxic gas emissions. Hydrometallurgy is the mainstream process, generally using an acidic solution to leach the cathode material, causing the valuable metals to dissolve in the solvent in ionic form. The valuable metals can then be recovered from the solution through precipitation, extraction, and ion exchange. However, this method results in the loss of metal ions in the solution and subsequent treatment of acidic and alkaline wastewater. There is an urgent need to develop an efficient recycling process that ensures a high recovery rate of valuable metals while minimizing the loss of metal ions in the solution and achieving green treatment of wastewater.

[0004] The patent application with application number CN202011620518.7 recovers nickel, cobalt, and manganese from cathode materials through ion adsorption and neutralization precipitation, and then recovers lithium carbonate through saturated crystallization. This method has a simple process flow and achieves the separation of nickel, cobalt, and manganese during the recovery process. However, the lithium recovery rate is unstable, and the subsequent lithium removal tailings are not treated, resulting in the loss of some lithium ions in the tailings.

[0005] The patent application with application number CN202310152154.1 uses an organic solution extraction method to separate and recover nickel, cobalt, and manganese, and then adds sodium carbonate to the lithium-rich aqueous phase to precipitate lithium. However, the recovery rates of nickel and lithium in this method are low, only 90% and 85%, respectively. Furthermore, no waste liquid treatment is performed on the organic solvents and lithium removal tail liquid generated in the experiment.

[0006] The patent application with application number CN202310940281.8 uses biodegradable organic acid leaching and recycles the waste liquid after lithium removal, obtaining sodium salt products after evaporation and crystallization. However, the organic acid leaching rate is relatively low and the cost is high, making it unsuitable for practical industrial applications. Furthermore, lithium carbonate is only slightly soluble in water, and the lithium removal tail liquid still contains a small amount of lithium ions. Directly recovering sodium salt from the tail liquid not only results in some lithium loss but also negatively impacts the purity of the sodium salt product.

[0007] The patent with application number CN202380009611.X uses a two-stage co-precipitation method of adding sodium hydroxide solution to the leaching solution. However, in its specific embodiments, the average recovery rate of nickel, cobalt and manganese is low, and the subsequent sodium sulfate waste liquid is not effectively treated. Summary of the Invention

[0008] To address the problems of low recovery rates of valuable metals and difficulty in treating subsequent waste liquid from waste ternary lithium batteries in existing technologies, this invention aims to provide a method for recovering valuable metals and recycling waste liquid from ternary lithium batteries. This method achieves efficient recovery of nickel, cobalt, and manganese through an acid leaching-reverse co-precipitation system, and treats the subsequent tailings liquid, realizing full-process metal recovery. This is a green and sustainable resource utilization solution for waste lithium batteries.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions: A. Disassemble, crush, and screen the waste ternary lithium batteries to obtain battery black powder. Immerse the battery black powder in alkaline solution and filter it after a certain period of time to obtain filter residue. B. Immerse the filter residue in a sulfuric acid solution at a certain temperature, and gradually add hydrogen peroxide solution until the solid is completely dissolved; C. Adjust the pH of the solution to 4.5, add a certain amount of trisodium phosphate to the leachate, and filter to obtain aluminum-removed leachate; D. Add a certain amount of ammonia water, nickel sulfate, manganese sulfate, and cobalt sulfate to the aluminum removal leaching solution, then add it back into the sodium hydroxide solution, and filter to obtain nickel co-precipitate and lithium-rich solution. E. Add trisodium phosphate to the lithium-rich solution, filter, and obtain lithium phosphate product and lithium removal tail liquid; F. Low-temperature crystallization is used to precipitate sodium sulfate decahydrate crystals from the high-sodium tail liquid. The crystals are then placed in a centrifuge for solid-liquid separation, and the remaining tail liquid is added to a lithium-rich solution.

[0010] In step A, the sodium hydroxide solution has a mass fraction of 10-15 wt.%, and the preferred solid-liquid ratio of sodium hydroxide solution to battery black powder during alkaline leaching is 1:2. The leaching time is 30-60 min. This step can dissolve Al impurities in the raw material in the sodium hydroxide solution, achieving preliminary separation of impurities.

[0011] In step S2, the concentration of sulfuric acid solution is 2-4 mol / L, the solid-liquid ratio of sulfuric acid solution to battery black powder during acid dissolution is preferably 4-6:1, the leaching temperature is preferably 70-90℃, and the mass fraction of hydrogen peroxide is 30 wt.%.

[0012] In step C, the molar ratio of trisodium phosphate added to aluminum ions in the leachate is 1.2:1.0, and the reaction time is 30-60 minutes. This step can reduce the concentration of aluminum ions in the leachate to within the national standard range.

[0013] In step D, the ammonia concentration after adding ammonia water to the leachate is preferably 5-9 g / L. The amount of nickel sulfate, cobalt sulfate, and manganese sulfate added is determined according to the molar ratio of nickel ions, cobalt ions, and manganese ions in the final ternary product, such as 1:1:1, 5:2:3, 8:1:1, etc.

[0014] In step D, the mass fraction of the sodium hydroxide solution is 15 wt.%, except that the volume ratio of aluminum leaching solution to sodium hydroxide solution is 0.7~1.0, the reaction time is preferably 30-60 min, and the co-precipitation reaction and filtration process are carried out under a carbon dioxide atmosphere.

[0015] In step E, the molar ratio of trisodium phosphate to lithium ions in the solution is 3.0~3.5:1, the reaction temperature is preferably 90℃, and the reaction time is preferably 30-60min.

[0016] In step F, the crystallization temperature is 5℃, the reaction time is 3~6h, and the centrifuge speed is set to 2000-3000rpm and the centrifugation time is 5-10min during the solid-liquid separation stage.

[0017] The advantages of this invention are: Leaching using alkaline leaching pretreatment can effectively reduce the aluminum ion content in the leachate. Subsequent aluminum removal using the phosphate method can stably reduce the aluminum ion content in the solution to below 50 ppm.

[0018] The nickel-cobalt-manganese co-precipitation step can achieve full recovery of nickel, cobalt, and manganese by back-adding the leaching solution to a sodium hydroxide solution.

[0019] Low-temperature crystallization is used to remove sodium from the subsequent lithium removal tail liquid, thereby realizing the resource utilization of the waste liquid.

[0020] During the sodium removal process, sodium sulfate crystallization carries away a large amount of water of crystallization, achieving secondary enrichment of lithium ions in the solution. Recycling the sodium removal tail liquid to the lithium removal stage for secondary lithium removal can effectively reduce the loss of lithium ions in the solution.

[0021] It enables the recycling of waste liquid, and is a green, economical and environmentally friendly recycling method. Attached Figure Description

[0022] Figure 1 This is a process flow diagram of a method for recovering valuable metals and recycling waste liquid from ternary lithium batteries provided by the present invention. Detailed Implementation

[0023] The specific embodiments of the present invention are further illustrated below, and the specific operation steps are as follows: The main components of the battery black powder in this invention are shown in Table 1: element Li Ni Co Mn Al Content (wt. %) 7.52 30.10 11.96 16.48 ＜0.1 Table 1 Example 1

[0024] A. Disassemble, crush, and screen the waste ternary lithium batteries to obtain battery black powder. Immerse 100.0g of battery black powder in 200.0ml of sodium hydroxide (15wt.%) solution, and filter for 40min to obtain 99.9g of filter residue. B. Immerse the filter residue in a 3 mol / L sulfuric acid solution at a liquid-to-solid ratio of 6:1 ml / g, heat to 90°C, and then gradually add hydrogen peroxide (30.0 wt.%) solution until all the solid is dissolved. C. Adjust the pH of the solution to 4.5, and measure the aluminum ion concentration in the solution to be 219.0 ppm. Add a certain amount of trisodium phosphate to the leachate (the molar ratio of the amount of trisodium phosphate added to the aluminum ions in the leachate is 1.2:1). After stirring and reacting for 40 min, filter to obtain 1150.0 ml of aluminum-removed leachate. At this time, the aluminum ion concentration in the solution is measured to be 25.0 ppm. D. Ammonia water was added to the aluminum removal leaching solution to control the ammonia concentration in the solution to 7 g / L. Then, nickel sulfate, manganese sulfate, and cobalt sulfate were added to adjust the nickel-cobalt-manganese ratio in the solution to 1:1:1. Under a carbon dioxide atmosphere, the aluminum removal leaching solution was added back to the sodium hydroxide solution (15.0 wt.%) at a volume ratio of 1.0 (aluminum removal leaching solution: sodium hydroxide solution). After stirring and reacting for 30 min, the mixture was filtered to obtain 90.1 g of ternary precursor material and 1045.0 ml of lithium-rich solution. The lithium-rich solution was sampled and analyzed. The concentrations of nickel, cobalt, and manganese in the solution were all below 5.0 ppm, and the recovery rate of nickel, cobalt, and manganese was as high as 99.9%. E. The solution was heated to 90°C, and trisodium phosphate (the molar ratio of trisodium phosphate to lithium ions in the solution was 3.3:1) was added. After stirring for 40 minutes, the mixture was filtered to obtain 39.1 g of lithium triphosphate product and 955.0 ml of lithium removal tail liquid. The lithium removal tail liquid was sampled and analyzed. The lithium ion concentration in the solution was 372.0 ppm, and the lithium recovery rate reached 93.4%. F. Place the lithium removal tail liquid in a 5℃ constant temperature chamber for 5 hours, then place it in a centrifuge for solid-liquid separation. Adjust the centrifuge speed to 2500 rpm and centrifuge for 10 minutes to obtain 422.1 g of sodium sulfate decahydrate product and 626.0 ml of sodium removal tail liquid. The sodium sulfate recovery rate in this process is 65.1%. At this time, the lithium ion concentration in the sodium removal tail liquid is 545.0 ppm, which can be further incorporated into the lithium removal stage. Example 2

[0025] A. Dismantle, crush, and screen the waste ternary lithium batteries to obtain battery black powder. Immerse 70.0g of battery black powder in 140ml of sodium hydroxide (10.0wt.%) solution, and filter for 60min to obtain 69.9g of filter residue. B. Immerse the filter residue in a 4 mol / L sulfuric acid solution at a liquid-to-solid ratio of 5:1 ml / g, heat to 80°C, and then gradually add hydrogen peroxide (30.0 wt.%) solution until all the solid is dissolved. C. Adjust the pH of the solution to 4.5, and measure the aluminum ion concentration in the solution to be 265.0 ppm. Add a certain amount of trisodium phosphate to the leachate (the molar ratio of the amount of trisodium phosphate added to the aluminum ions in the leachate is 1.2:1). After stirring and reacting for 30 min, filter to obtain 990.0 ml of aluminum-removed leachate. At this time, the aluminum ion concentration in the solution is measured to be 31.0 ppm. D. Ammonia water was added to the aluminum removal leaching solution to control the ammonia concentration in the solution to 9 g / L. Then, nickel sulfate, manganese sulfate, and cobalt sulfate were added to adjust the nickel-cobalt-manganese ratio in the solution to 1:1:1. Under a carbon dioxide atmosphere, the aluminum removal leaching solution was back-added to the sodium hydroxide solution (15.0 wt.%) at a volume ratio of 0.8 (aluminum removal leaching solution: sodium hydroxide solution). After stirring and reacting for 40 min, the mixture was filtered to obtain 63.1 g of ternary precursor material and 882.0 ml of lithium-rich solution. The lithium-rich solution was sampled and analyzed. The concentrations of nickel, cobalt, and manganese in the solution were all below 5.0 ppm, and the recovery rate of nickel, cobalt, and manganese was as high as 99.9%. E. Heat the solution to 90°C, add trisodium phosphate (the molar ratio of trisodium phosphate to lithium ions in the solution is 3.5:1), stir and react for 30 minutes, then filter to obtain 27.7g of lithium triphosphate product and 810.0ml of lithium removal tail liquid. Analysis of the lithium removal tail liquid showed a lithium ion concentration of 305.0ppm and a lithium recovery rate of 94.6%. F. Place the lithium removal tail liquid in a 5℃ constant temperature chamber for 6 hours, then place it in a centrifuge for solid-liquid separation. Adjust the centrifuge speed to 2500 rpm and centrifuge for 9 minutes to obtain 350.8 g of sodium sulfate decahydrate product and 538.0 ml of sodium removal tail liquid. The sodium sulfate recovery rate in this process is 63.7%. At this time, the lithium ion concentration in the sodium removal tail liquid is 472.0 ppm, which can be further incorporated into the lithium removal stage. Example 3

[0026] A. Dismantle, crush, and screen the waste ternary lithium batteries to obtain battery black powder. Immerse 130.0g of battery black powder in 260.0ml of sodium hydroxide (13wt.%) solution, and filter for 30min to obtain 129.9g of filter residue. B. Immerse the filter residue in a 4 mol / L sulfuric acid solution at a liquid-to-solid ratio of 4:1 ml / g, heat to 90°C, and then gradually add hydrogen peroxide (30.0 wt.%) solution until all the solid is dissolved. C. Adjust the pH of the solution to 4.5, and measure the aluminum ion concentration in the solution to be 232.0 ppm. Add a certain amount of trisodium phosphate to the leachate (the molar ratio of the amount of trisodium phosphate added to the aluminum ions in the leachate is 1.2:1). After stirring and reacting for 50 min, filter to obtain 1075.0 ml of aluminum-removed leachate. At this time, the aluminum ion concentration in the solution is measured to be 23.0 ppm. D. Ammonia was added to the aluminum removal leaching solution to control the ammonia concentration in the solution to 9 g / L. Then, nickel sulfate, manganese sulfate, and cobalt sulfate were added to adjust the nickel-cobalt-manganese ratio in the solution to 1:1:1. Under a carbon dioxide atmosphere, the aluminum removal leaching solution was back-added to the sodium hydroxide solution (15.0 wt.%) at a volume ratio of 0.7 (aluminum removal leaching solution: sodium hydroxide solution). After stirring and reacting for 50 min, the mixture was filtered to obtain 117.3 g of ternary precursor material and 905.0 ml of lithium-rich solution. The lithium-rich solution was sampled and analyzed. The concentrations of nickel, cobalt, and manganese in the solution were all below 5.0 ppm, and the recovery rate of nickel, cobalt, and manganese was as high as 99.9%. E. The solution was heated to 90°C, and trisodium phosphate (the molar ratio of trisodium phosphate to lithium ions in the solution was 3.5:1) was added. After stirring for 30 minutes, the mixture was filtered to obtain 54.3 g of lithium triphosphate product and 815.0 ml of lithium removal tail liquid. The lithium removal tail liquid was sampled and analyzed. The lithium ion concentration in the solution was 436.0 ppm, and the lithium recovery rate reached 92.3%. F. Place the lithium removal tail liquid in a 5℃ constant temperature chamber for 5 hours, then place it in a centrifuge for solid-liquid separation. Adjust the centrifuge speed to 2000 rpm and centrifuge for 5 minutes to obtain 334.0 g of sodium sulfate decahydrate product and 558.0 ml of sodium removal tail liquid. The sodium sulfate recovery rate in this process is 62.4%. At this time, the lithium ion concentration in the sodium removal tail liquid is 603.0 ppm, which can be further incorporated into the lithium removal stage. Example 4

[0027] A. Dismantle, crush, and screen the waste ternary lithium batteries to obtain battery black powder. Immerse 110.0g of battery black powder in 220.0ml of sodium hydroxide (11wt.%) solution, and filter for 50min to obtain 109.9g of filter residue. B. Immerse the filter residue in a 2 mol / L sulfuric acid solution at a liquid-to-solid ratio of 6:1 ml / g, heat to 90°C, and then gradually add hydrogen peroxide (30.0 wt.%) solution until all the solid is dissolved. C. Adjust the pH of the solution to 4.5, and measure the aluminum ion concentration in the solution to be 196.0 ppm. Add a certain amount of trisodium phosphate to the leachate (the molar ratio of the amount of trisodium phosphate added to the aluminum ions in the leachate is 1.2:1). After stirring and reacting for 60 min, filter to obtain 1310.0 ml of aluminum-removed leachate. At this time, the aluminum ion concentration in the solution is measured to be 19.0 ppm. D. Ammonia water was added to the aluminum removal leaching solution to control the ammonia concentration in the solution to 5 g / L. Then, nickel sulfate, manganese sulfate, and cobalt sulfate were added to adjust the nickel-cobalt-manganese ratio in the solution to 1:1:1. Under a carbon dioxide atmosphere, the aluminum removal leaching solution was added back to the sodium hydroxide solution (15.0 wt.%) at a volume ratio of 0.8 (aluminum removal leaching solution: sodium hydroxide solution). After stirring and reacting for 60 min, the mixture was filtered to obtain 99.3 g of ternary precursor material and 1095.0 ml of lithium-rich solution. The lithium-rich solution was sampled and analyzed. The concentrations of nickel, cobalt, and manganese in the solution were all below 5.0 ppm, and the recovery rate of nickel, cobalt, and manganese was as high as 99.9%. E. Heat the solution to 90°C, add trisodium phosphate (the molar ratio of trisodium phosphate to lithium ions in the solution is 3.4:1), stir and react for 60 min, then filter to obtain 46.0 g of lithium triphosphate product and 990.0 ml of lithium removal tail liquid. Analysis of the lithium removal tail liquid showed a lithium ion concentration of 354.0 ppm and a lithium recovery rate of 93.7%. F. Place the lithium removal tail liquid in a 5℃ constant temperature chamber for 3 hours, then place it in a centrifuge for solid-liquid separation. Adjust the centrifuge speed to 3000 rpm and centrifuge for 9 minutes to obtain 503.0 g of sodium sulfate decahydrate product and 590.0 ml of sodium removal tail liquid. The sodium sulfate recovery rate in this process is 68.6%. At this time, the lithium ion concentration in the sodium removal tail liquid is 577 ppm, which can be further incorporated into the lithium removal stage.

Claims

1. A method for recovering valuable metals and recycling waste liquid from ternary lithium batteries, relating to the field of waste lithium battery recycling, the main characteristic steps of which are as follows: A. Disassemble, crush, and screen the waste ternary lithium batteries to obtain battery black powder. Immerse the battery black powder in alkaline solution and filter it after a certain period of time to obtain filter residue. B. Immerse the filter residue in sulfuric acid solution, and gradually add hydrogen peroxide solution until the solid is completely dissolved; C. Adjust the pH of the solution to 4.5, add a certain amount of trisodium phosphate to the leachate, and filter to obtain aluminum-removed leachate; D. Add a certain amount of ammonia water, nickel sulfate, manganese sulfate, and cobalt sulfate to the aluminum removal leaching solution, then add it back into the sodium hydroxide solution, and filter to obtain nickel co-precipitate and lithium-rich solution. E. Add trisodium phosphate to the lithium-rich solution, filter, and obtain lithium phosphate product and lithium removal tail liquid; F. Low-temperature crystallization is used to precipitate sodium sulfate decahydrate crystals from the high-sodium tail liquid. The crystals are then placed in a centrifuge for solid-liquid separation, and the remaining tail liquid is added to a lithium-rich solution.

2. The method for recovering valuable metals and recycling waste liquid from ternary lithium batteries as described in claim 1, characterized in that, In step A, the sodium hydroxide solution has a mass fraction of 10-15 wt.%, and the preferred solid-liquid ratio of sodium hydroxide solution to battery black powder during alkaline leaching is 1:2, with an alkali leaching time of 30-60 min.

3. The method for recovering valuable metals and recycling waste liquid from ternary lithium batteries as described in claim 1, characterized in that, In step B, the concentration of sulfuric acid solution is 2-4 mol / L, the solid-liquid ratio of sulfuric acid solution to battery black powder during acid dissolution is preferably 4-6:1, the leaching temperature is preferably 70-90℃, and the mass fraction of hydrogen peroxide is 30 wt.%.

4. The method for recovering valuable metals and recycling waste liquid from ternary lithium batteries as described in claim 1, characterized in that, In step C, the molar ratio of trisodium phosphate added to aluminum ions in the leachate is 1.2:1.0, and the reaction time is 30-60 min.

5. The method for recovering valuable metals and recycling waste liquid from ternary lithium batteries as described in claim 1, characterized in that, In step D, the aluminum ion concentration in the aluminum leaching solution is <150ppm, and the ammonia concentration is 5~9g / L.

6. The method for recovering valuable metals and recycling waste liquid from ternary lithium batteries as described in claim 1, characterized in that, The amount of nickel sulfate, cobalt sulfate, and manganese sulfate added in step D is determined according to the molar ratio of nickel ions, cobalt ions, and manganese ions in the final required ternary product.

7. The method for recovering valuable metals and recycling waste liquid from ternary lithium batteries as described in claim 1, characterized in that, In step D, the sodium hydroxide solution has a mass fraction of 15 wt.%, except that the volume ratio of aluminum leaching solution to sodium hydroxide solution is 0.7~1.

0. The coprecipitation reaction and filtration process are carried out under a carbon dioxide atmosphere.

8. The method for recovering valuable metals and recycling waste liquid from ternary lithium batteries as described in claim 1, characterized in that, In step D, the nickel-cobalt-manganese co-precipitation method involves adding the leachate back into the sodium hydroxide solution.

9. The method for recovering valuable metals and recycling waste liquid from ternary lithium batteries as described in claim 1, characterized in that, In step E, the molar ratio of trisodium phosphate to lithium ions in the solution is 3.0~3.5:1, the reaction temperature is preferably 90℃, and the reaction time is preferably 30-60min.

10. The method for recovering valuable metals and recycling waste liquid from ternary lithium batteries as described in claim 1, characterized in that, In step F, the crystallization temperature is 5℃ and the reaction time is 3-6h; in the solid-liquid separation stage, the centrifuge speed is set to 2000-3000rpm and the centrifugation time is 5-10min.

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