Method for recovering cobalt from spent battery cathode material

Abstract

The present application relates to waste battery recycling technical field, specifically to a kind of method for recovering cobalt in waste battery positive material.The method is: low eutectic solvent is mixed with waste battery positive material powder, heated and stirred, to obtain solution one;Extracting agent is first acidified using equal volume of dilute hydrochloric acid, then mixed with solution one, stirred at room temperature, after extraction, separation, to obtain waste battery positive material dissolved in extracting agent;Waste battery positive material dissolved in extracting agent is mixed with water, stirred at room temperature, back extraction, after back extraction, separation, to obtain waste battery positive material dissolved in aqueous solution;Salt solution is used to titrate waste battery positive material dissolved in aqueous solution, until the precipitate is completely.The method for recovering cobalt in waste battery positive material used in the present application has low eutectic solvent composition, low price, easy to obtain, small degree of environmental pollution, in line with the concept of "green chemistry";The final product obtained by the present application has high cobalt content and good separation effect.

Description

Technical Field

[0001] This invention relates to the field of waste battery recycling technology, specifically to a method for recovering cobalt from the positive electrode material of waste batteries. Background Technology

[0002] Since lithium cobalt oxide was adopted as the cathode material for lithium-ion rechargeable batteries, its superior properties, such as small size, high energy density, absence of memory effect, and low self-discharge, have led to its increasingly widespread application in energy storage devices and new energy vehicles. However, with the rapid development of new energy vehicles, the demand for lithium-ion batteries has increased dramatically, resulting in a continuous rise in the prices of metals such as lithium and cobalt needed to manufacture them. Cobalt is a globally scarce metal resource, and countries around the world are employing various means to compete for it, making it difficult to obtain. Furthermore, due to the limited lifespan of lithium-ion batteries, a large number of waste lithium-ion batteries are generated after they are scrapped. If these waste lithium-ion batteries are disposed of improperly without treatment, the heavy metals they contain will seriously harm the soil and groundwater, becoming a major problem hindering sustainable social development. Therefore, research on the recycling and utilization of cobalt resources from waste lithium-ion batteries is a necessary and urgent task.

[0003] Commonly used technologies for recycling spent lithium-ion batteries include pyrometallurgy, hydrometallurgy, biometallurgy, and mechanical methods. Pyrometallurgy is the dominant industrial method, but it typically requires high smelting temperatures (1400℃ or higher), resulting in high energy costs and the emission of large amounts of harmful gases, necessitating strict safety precautions and pollution control facilities. Hydrometallurgy is also a commonly used method, offering high metal leaching rates and high purity of recycled products. However, this technology often requires the use of corrosive solvents such as hydrochloric acid, sulfuric acid, and nitric acid, posing serious hazards to workers and the environment. Summary of the Invention

[0004] In view of this, it is necessary to provide a method for recycling cobalt from the positive electrode material of spent batteries, addressing the aforementioned problems. This invention does not use corrosive solvents such as strong acids or alkalis, but employs a eutectic solvent with inexpensive components, avoiding secondary pollution. The recovered final product has a high cobalt content, and the process is simple and environmentally friendly.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for recycling cobalt from the positive electrode material of waste batteries includes the following steps:

[0007] Step 1: Mix the eutectic solvent with the powdered positive electrode material from the waste battery, heat and stir to obtain Solution 1;

[0008] Step 2: First, acidify the extractant with an equal volume of dilute hydrochloric acid, then mix it with the solution in Step 1, stir and extract at room temperature, and separate after extraction to obtain the extractant containing the positive electrode material of the waste battery.

[0009] Step 3: Mix the extractant containing the positive electrode material of the waste battery from Step 2 with water, stir and back-extract at room temperature, and separate after back-extraction to obtain an aqueous solution containing the positive electrode material of the waste battery.

[0010] Step 4: Titrate the aqueous solution containing the spent battery positive electrode material from Step 3 with a salt solution until precipitation is complete.

[0011] Furthermore, the cathode material of the waste battery is waste lithium cobalt oxide cathode material.

[0012] Furthermore, the eutectic solvent is formed by mixing choline chloride and malonic acid in a certain proportion.

[0013] Furthermore, the malonic acid is replaced with oxalic acid.

[0014] Furthermore, the molar ratio of choline chloride to malonic acid / oxic acid is 1:(1-2).

[0015] Preferably, the molar ratio of choline chloride to malonic acid / oxic acid is 1:1.

[0016] Furthermore, in step 1, the mass ratio of the eutectic solvent to the waste battery cathode material powder is (100-200):1.

[0017] Preferably, in step 1, the mass ratio of the eutectic solvent to the waste battery cathode material powder is 100:1.

[0018] Furthermore, the heating temperature in step 1 is 50–100°C.

[0019] Furthermore, the extractant in step 2 is formed by mixing N235 extractant, sulfonated kerosene, and tributyl phosphate (TBP) in a certain proportion.

[0020] Preferably, the volume ratio of N235 extractant, TBP and sulfonated kerosene is (3-5):2:5.

[0021] Furthermore, in step 4, the salt solution is an aqueous solution of sodium carbonate, and the concentration of the sodium carbonate solution is 1-2 mol / L.

[0022] Furthermore, the precipitate obtained in step 4 is washed and dried.

[0023] The beneficial effects of this invention are as follows:

[0024] The method for recycling cobalt from the positive electrode material of waste batteries in this invention does not use corrosive solutions such as strong acids and strong alkalis. The eutectic solvent used has inexpensive and readily available components, resulting in minimal environmental pollution and conforming to the concept of "green chemistry." The final product obtained by this invention has a high cobalt content and excellent separation effect. The eutectic solvent and extractant used in the process of this invention can be recycled and reused, reducing process costs. The main process of this invention consists of dissolution, extraction, and back-extraction, making the process simple and easy to operate. Attached Figure Description

[0025] Figure 1 This is the XRD pattern of the precipitate obtained in Example 1 of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be further described clearly and completely below in conjunction with the embodiments of this invention. It should be noted that the described embodiments are merely some embodiments of this invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] The waste batteries used in the embodiments of this invention are all waste lithium cobalt oxide batteries, which are recycled from a certain second-hand recycling station, and the reagents used are all commercially available.

[0028] In the following embodiments, the positive electrode sheet of the waste lithium cobalt oxide battery was disassembled, roasted, washed, filtered and dried to obtain waste lithium cobalt oxide positive electrode material powder.

[0029] Example 1

[0030] A method for recycling cobalt from the positive electrode material of waste batteries includes the following steps:

[0031] Step 1: Mix the eutectic solvent with the waste battery positive electrode material powder, heat and stir to dissolve it, and obtain Solution 1; wherein the mass ratio of the eutectic solvent to the waste battery positive electrode material powder is 100g:1g; the heating temperature is 90℃; the eutectic solvent is formed by mixing choline chloride and malonic acid in a molar ratio of 1:1.

[0032] Step 2: Mix N235 extractant, TBP and sulfonated kerosene in a volume ratio of 3:2:5 to form 150 mL of extractant; acidify the extractant with an equal volume of 15% hydrochloric acid; mix the acidified extractant with solution 1 from step 1, stir and extract at room temperature, separate after extraction to obtain extractant containing waste battery positive electrode material, and recover the eutectic solvent;

[0033] Step 3: Mix the extractant containing the waste battery positive electrode material from Step 2 with 150 mL of water, stir and back-extract at room temperature, separate after back-extraction to obtain an aqueous solution containing the waste battery positive electrode material, and recover the extractant;

[0034] Step 4: Titrate the aqueous solution containing the waste battery positive electrode material from Step 3 with a 1 mol / L sodium carbonate solution until precipitation is complete; wash and dry the resulting precipitate.

[0035] The prepared precipitate was weighed to 1.01 g, and after quantitative calculation, the extraction rate of cobalt in lithium cobalt oxide was found to be 83.4%.

[0036] Comparative Example 1

[0037] A method for recycling cobalt from the positive electrode material of spent batteries differs from Example 1 in that dilute hydrochloric acid was not used to acidify the extractant in step 2. The prepared precipitate was weighed at 0.12 g, and after quantitative calculation, the extraction rate of cobalt from lithium cobalt oxide was found to be 9.6%.

[0038] Example 2

[0039] A method for recycling cobalt from the positive electrode material of waste batteries includes the following steps:

[0040] Step 1: Mix the eutectic solvent with the waste battery positive electrode material powder, heat and stir to dissolve it, and obtain Solution 1; wherein the mass ratio of the eutectic solvent to the waste battery positive electrode material powder is 200g:1g; the heating temperature is 90℃; the eutectic solvent is formed by mixing choline chloride and malonic acid in a molar ratio of 1:2.

[0041] Step 2: Mix N235 extractant, TBP and sulfonated kerosene in a volume ratio of 3:2:5 to form 200 mL of extractant; acidify the extractant with an equal volume of 15% hydrochloric acid; mix the acidified extractant with solution 1 from step 1, stir and extract at room temperature, separate after extraction to obtain extractant containing waste battery positive electrode material, and recover the eutectic solvent;

[0042] Step 3: Mix the extractant containing the waste battery positive electrode material from Step 2 with 200 mL of water, stir and back-extract at room temperature, separate after back-extraction to obtain an aqueous solution containing the waste battery positive electrode material, and recover the extractant;

[0043] Step 4: Titrate the aqueous solution containing the waste battery positive electrode material from Step 3 with a 1 mol / L sodium carbonate solution until precipitation is complete; wash and dry the resulting precipitate.

[0044] The prepared precipitate was weighed to 0.70 g, and after quantitative calculation, the extraction rate of cobalt in lithium cobalt oxide was found to be 58.1%.

[0045] Comparative Example 2

[0046] A method for recycling cobalt from the positive electrode material of spent batteries differs from Example 2 in that dilute hydrochloric acid was not used to acidify the extractant in step 2. The prepared precipitate was weighed to 0.06 g, and after quantitative calculation, the extraction rate of cobalt from lithium cobalt oxide was found to be 5.1%.

[0047] Comparing Example 1 and Comparative Example 1, and Example 2 and Comparative Example 2 respectively, it is shown that the extractant must be acidified in order to significantly improve the extraction effect.

[0048] Example 3

[0049] This embodiment examines a method for recovering cobalt from spent battery cathode materials using a recycled eutectic solvent. The difference from Example 1 is that a recycled eutectic solvent is used; otherwise, the methods are the same as in Example 1. The number of cycles and the final obtained lithium cobalt oxide and its cobalt composition are shown in Table 1.

[0050] Table 1

[0051]

[0052]

[0053] The data in Table 1 show that the ability to extract cobalt decreases as the number of cycles of the recycled eutectic solvent increases; therefore, the recycling cycle should not be reused more than 3 times.

[0054] Example 4

[0055] This embodiment examines a method for recovering cobalt from spent battery cathode materials using a recycled extractant. The difference from Embodiment 1 is that a recycled extractant is used; otherwise, the methods are the same as in Embodiment 1. The number of cycles and the final obtained lithium cobalt oxide and its cobalt composition are shown in Table 2.

[0056] Table 2

[0057]

[0058] The data in Table 2 show that the recovery of the extractant has a relatively small impact on the cobalt extraction results. Therefore, it is recommended that the number of times the recovery and recycling process is controlled within 5 times.

[0059] Example 5

[0060] A method for recycling cobalt from the positive electrode material of waste batteries includes the following steps:

[0061] Step 1: Mix the eutectic solvent with the waste battery positive electrode material powder, heat and stir to dissolve it, and obtain Solution 1; wherein the mass ratio of the eutectic solvent to the waste battery positive electrode material powder is 100g:1g; the heating temperature is 90℃; the eutectic solvent is formed by mixing choline chloride and oxalic acid in a molar ratio of 1:1.

[0062] Step 2: Mix N235 extractant, TBP and sulfonated kerosene in a volume ratio of 3:2:5 to form 150 mL of extractant; acidify the extractant with an equal volume of 15% hydrochloric acid; mix the acidified extractant with solution 1 from step 1, stir and extract at room temperature, and separate after extraction to obtain extractant containing waste battery positive electrode material.

[0063] Step 3: Mix the extractant containing the positive electrode material of the waste battery from Step 2 with 150 mL of water, stir and back-extract at room temperature, and separate after back-extraction to obtain an aqueous solution containing the positive electrode material of the waste battery.

[0064] Step 4: Titrate the aqueous solution containing the waste battery positive electrode material from Step 3 with a 1 mol / L sodium carbonate solution until precipitation is complete; wash and dry the resulting precipitate.

[0065] The prepared precipitate was weighed to 0.81 g, and after quantitative calculation, the extraction rate of cobalt in lithium cobalt oxide was found to be 67.4%.

[0066] In this embodiment, malonic acid can be replaced with oxalic acid, and it can also be used for cobalt extraction.

[0067] Example 6

[0068] A method for recycling cobalt from the positive electrode material of waste batteries includes the following steps:

[0069] Step 1: Mix the eutectic solvent with the waste battery positive electrode material powder, heat and stir to dissolve it, and obtain Solution 1; wherein the mass ratio of the eutectic solvent to the waste battery positive electrode material powder is 100g:1g; the heating temperature is 90℃; the eutectic solvent is formed by mixing choline chloride and malonic acid in a molar ratio of 1:3.

[0070] Step 2: Mix N235 extractant, TBP and sulfonated kerosene in a volume ratio of 3:2:5 to form 150 mL of extractant; acidify the extractant with an equal volume of 15% hydrochloric acid; mix the acidified extractant with solution 1 from step 1, stir and extract at room temperature, and separate after extraction to obtain extractant containing waste battery positive electrode material.

[0071] Step 3: Mix the extractant containing the positive electrode material of the waste battery from Step 2 with 150 mL of water, stir and back-extract at room temperature, and separate after back-extraction to obtain an aqueous solution containing the positive electrode material of the waste battery.

[0072] Step 4: Titrate the aqueous solution containing the waste battery positive electrode material from Step 3 with a 1 mol / L sodium carbonate solution until precipitation is complete; wash and dry the resulting precipitate.

[0073] The prepared precipitate was weighed to 0.34 g, and after quantitative calculation, the extraction rate of cobalt in lithium cobalt oxide was found to be 28.6%.

[0074] In this embodiment, the amount of malonic acid used was slightly increased, but the extraction of cobalt was significantly reduced.

[0075] Example 7

[0076] A method for recycling cobalt from the positive electrode material of waste batteries includes the following steps:

[0077] Step 1: Mix the eutectic solvent with the waste battery positive electrode material powder, heat and stir to dissolve it, and obtain Solution 1; wherein the mass ratio of the eutectic solvent to the waste battery positive electrode material powder is 100g:1g; the heating temperature is 90℃; the eutectic solvent is formed by mixing choline chloride and malonic acid in a molar ratio of 1:1.

[0078] Step 2: Mix N235 extractant, TBP and sulfonated kerosene in a volume ratio of 1:2:5 to form 150 mL of extractant; acidify the extractant with an equal volume of 15% hydrochloric acid; mix the acidified extractant with solution 1 from step 1, stir and extract at room temperature, and separate after extraction to obtain extractant containing waste battery positive electrode material.

[0079] Step 3: Mix the extractant containing the positive electrode material of the waste battery from Step 2 with 150 mL of water, stir and back-extract at room temperature, and separate after back-extraction to obtain an aqueous solution containing the positive electrode material of the waste battery.

[0080] Step 4: Titrate the aqueous solution containing the waste battery positive electrode material from Step 3 with a 1 mol / L sodium carbonate solution until precipitation is complete; wash and dry the resulting precipitate.

[0081] The prepared precipitate was weighed to 0.66 g, and after quantitative calculation, the extraction rate of cobalt in lithium cobalt oxide was found to be 55.3%.

[0082] In this embodiment, the amount of extractant was adjusted, and the amount of N235 extractant was reduced, resulting in a certain degree of decrease compared to the results of Example 1.

[0083] Other experimental data

[0084] The cobalt-containing precipitate obtained in Example 1 was analyzed by XRD, and the results are as follows: Figure 1 As shown. By Figure 1 It can be seen that cobalt mainly exists in the precipitate in the form of hydroxides and oxides, and the causative factors of both forms of cobalt are below 10, indicating that their presence is highly probable; while the causative factor of lithium precipitate is above 100, which can be considered as its non-existence. Therefore, this embodiment has achieved good separation and extraction results.

[0085] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for recycling cobalt from the positive electrode material of waste batteries, characterized in that, Includes the following steps: Step 1: Mix the eutectic solvent with the powdered positive electrode material from the waste battery, heat and stir to obtain Solution 1; Step 2: First, acidify the extractant with an equal volume of dilute hydrochloric acid, then mix it with the solution in Step 1, stir and extract at room temperature, and separate after extraction to obtain the extractant containing the positive electrode material of the waste battery. Step 3: Mix the extractant containing the positive electrode material of the waste battery from Step 2 with water, stir and back-extract at room temperature, and separate after back-extraction to obtain an aqueous solution containing the positive electrode material of the waste battery. Step 4: Titrate the aqueous solution containing the spent battery positive electrode material from Step 3 with salt solution until precipitation is complete; The eutectic solvent is formed by mixing choline chloride with malonic acid or oxalic acid in a certain proportion. The molar ratio of choline chloride to malonic acid or oxalic acid is 1:(1~2). In step 1, the mass ratio of the eutectic solvent to the waste battery cathode material powder is (100~200):

1.

2. The method for recycling cobalt in the positive electrode material of waste batteries according to claim 1, characterized in that, The cathode material of the waste battery is waste lithium cobalt oxide cathode material.

3. The method for recycling cobalt in the positive electrode material of waste batteries according to claim 1, characterized in that, The heating temperature in step 1 is 50~100℃.

4. The method for recycling cobalt in the positive electrode material of waste batteries according to claim 1, characterized in that, The extractant in step 2 is a mixture of N235 extractant, sulfonated kerosene and TBP in a certain proportion.

5. The method for recycling cobalt in the positive electrode material of waste batteries according to claim 4, characterized in that, The volume ratio of N235 extractant, TBP and sulfonated kerosene is (3~5):2:

5.

6. The method for recycling cobalt in the positive electrode material of waste batteries according to claim 1, characterized in that, In step 4, the salt solution is an aqueous solution of sodium carbonate with a concentration of 1-2 mol / L.

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