Method for selectively recycling nickel, cobalt and manganese in waste ternary lithium battery positive electrode material through deep eutectic solvent

Abstract

The invention belongs to the technical field of waste lithium battery treatment, and particularly relates to a method for selectively recycling nickel, cobalt and manganese in a waste ternary lithium battery positive electrode material through a deep eutectic solvent. The method comprises the following steps: firstly, mixing chloroacetic acid and betaine hydrochloride to prepare a deep eutectic solvent, and then mixing SNCM positive electrode material powder with the deep eutectic solvent for leaching to obtain a leaching solution; then adding absolute ethyl alcohol into the leachate to obtain manganese and cobalt betaine hydrochloride chelate and a nickel-containing solution 1; adding anhydrous oxalic acid into the solution 1 to obtain nickel oxalate precipitate; dissolving the cobalt and manganese betaine hydrochloride chelate in water again to obtain a solution 2 containing cobalt and manganese; adding anhydrous oxalic acid into the solution 2 and adjusting the pH value of the solution; a cobalt oxalate precipitate and a manganese-containing solution 3 are obtained; and adjusting the pH value of the manganese-containing solution 3 to obtain a manganese hydroxide precipitate. According to the method, use of strong acid and strong alkali is avoided, step-by-step recovery of valuable metal is achieved, higher selectivity is achieved, and generation of salt-containing wastewater is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of waste lithium battery treatment, and specifically relates to a method for selectively recovering nickel, cobalt and manganese from positive electrode materials of waste ternary lithium batteries by using a deep eutectic solvent. Background Art

[0002] With the continuous development of new energy vehicles and portable devices, lithium-ion batteries (LIBs) have become the mainstream energy storage device today due to their good stability, high energy density and low self-discharge rate. However, as lithium-ion batteries are put into commercial use on a large scale, they are also retired on a large scale, resulting in the need to scrap waste lithium batteries. Since waste LIBs contain a large amount of heavy metals and toxic and hazardous substances, if they are not properly treated, they will cause serious pollution to the environment. At the same time, waste LIBs contain a large amount of valuable metals such as Li, Ni, Co, Mn, Cu, and Al, and are called "urban mines". They are very precious secondary resources with high recycling value. Therefore, recycling waste LIBs can not only alleviate the pressure of resource demand, but also reduce the harm of toxic substances to the environment. In addition, optimizing the recycling and reuse of these metal resources by improving the recycling of lithium-ion batteries will help to ensure the safety and recycling of resources and reduce the total cost of battery production.

[0003] At present, the recycling of waste LIBs mainly focuses on the recovery of valuable metals in the positive electrode materials. The commonly used methods are pyrometallurgy and hydrometallurgy. Pyrometallurgy mainly converts valuable metals such as Li, Ni, Co, and Mn in the positive electrode materials into alloys for recycling by high-temperature calcination. Although pyrometallurgical technology is simple to operate, its high energy consumption, large amount of waste gas generation, and poor metal selective separation effect limit the widespread application of pyrometallurgical technology. Hydrometallurgical technology mainly uses inorganic acid leaching or organic acid leaching to immerse the valuable metals in the positive electrode materials into a solvent, and then separates and purifies Li, Ni, Co, Mn and other valuable metals by chemical precipitation, extraction, electrodeposition, etc.

[0004] Deep eutectic solvent (DES) is an organic solvent similar to ionic liquids composed of hydrogen bond donors and hydrogen bond acceptors. DES was first used to recover valuable metals in the positive electrode materials of waste lithium batteries in 2019. Due to the unique coordination ability and reduction ability of DES, it has excellent performance in the field of waste battery recycling. However, existing technologies often only focus on the leaching of valuable metals, and there is insufficient research on the separation and recovery of valuable metals at the back end. In addition, the similar properties of transition metals such as Ni, Co, and Mn also increase the difficulty of subsequent separation and purification steps. Therefore, it is urgent to develop a new method for green, efficient, and highly selective recovery of valuable metals in the positive electrode materials of waste lithium batteries. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a green, economical and efficient method for producing less salt-containing wastewater from spent LiNi x Co y Mn 1-x-y A new method for separating and recovering nickel, cobalt and manganese from positive electrode materials (O2, SNCM). To achieve the above purpose, the technical scheme of the present invention is as follows:

[0006] (1) Preparation of deep eutectic solvent: Chloroacetic acid and betaine hydrochloride were mixed in a certain molar ratio. In order to better form a deep eutectic solvent, 30 wt % of water was added as a co-solvent. The mixture was then heated and stirred in a water bath at 80° C. for 30 min. The obtained deep eutectic solvent was recorded as C-DES.

[0007] Wherein, the molar ratio of chloroacetic acid to betaine hydrochloride is 2 to 4:1.

[0008] (2) Leaching of precious metals: After the SNCM cathode material powder and C-DES are uniformly mixed in a certain solid-liquid ratio, the mixture is heated and stirred in a water bath. After the leaching is completed, the mixed solution is filtered through a 0.22 μm PTFE filter membrane to obtain a leachate.

[0009] Among them, the solid-liquid ratio of SNCM positive electrode material powder to C-DES is 5g / L to 20g / L.

[0010] The water bath heating and stirring temperature is 80°C to 95°C, the time is 1h to 3h, and the stirring rate is 500rpm.

[0011] (3) Separation and recovery of nickel, cobalt and manganese:

[0012] 1) adding anhydrous ethanol to the leaching solution obtained in step (2), stirring at room temperature to generate manganese and cobalt betaine hydrochloride chelate crystals, and separating by filtration to obtain manganese and cobalt betaine hydrochloride chelate and a nickel-containing solution 1.

[0013] The volume ratio of the added anhydrous ethanol to the leaching solution is 9-12:1, the stirring time is 2h-3h, and the stirring rate is 350rpm.

[0014] 2) Anhydrous oxalic acid is added to solution 1 to form nickel oxalate, and nickel oxalate precipitate is obtained by filtration and separation. Subsequently, the obtained cobalt and manganese betaine hydrochloride chelate is redissolved in water at a solid-liquid ratio of 10 g / L to obtain a solution 2 containing cobalt and manganese.

[0015] The molar ratio of the added anhydrous oxalic acid to the nickel in solution 1 is 1:1.

[0016] 3) Anhydrous oxalic acid is added to solution 2 and the pH value of the solution is adjusted with aqueous ammonia. The solution is then heated in a water bath for a certain period of time to form a cobalt oxalate precipitate, which is filtered and separated to obtain the cobalt oxalate precipitate and the manganese-containing solution 3. The pH value of the manganese-containing solution 3 is adjusted to alkaline with aqueous ammonia to form a manganese hydroxide precipitate, which is filtered to obtain the manganese hydroxide precipitate.

[0017] The molar ratio of the added anhydrous oxalic acid to the cobalt in solution 2 is 2-3:1, the pH value of solution 2 is adjusted to 2-3, the water bath temperature is 60° C., and the water bath time is 1 h.

[0018] The pH value of solution 3 was adjusted to 12.

[0019] The recovery rate of valuable metal ions is calculated by formula (1):

[0020]

[0021] Wherein: η is the recovery efficiency, %. m is the mass of the recovered products of nickel, cobalt and manganese, g. D is the relative molecular mass proportion of nickel, cobalt and manganese in the recovered products, %. m0 is the mass of the SNCM positive electrode material before recovery, g. W0 is the mass fraction of nickel, cobalt and manganese in the SNCM positive electrode material before recovery, %.

[0022] The present invention adopts chloroacetic acid and betaine hydrochloride to synthesize a deep eutectic solvent, and can realize efficient leaching of valuable metals in the positive electrode material of waste ternary lithium batteries under relatively mild conditions. And according to the solution environment of the leachate, considering the different solubility of betaine hydrochloride and the different polar environments, the polarity of the solution is changed by adding anhydrous ethanol, so that the betaine hydrochloride is recrystallized and precipitated. The precipitated betaine hydrochloride further chelates manganese and cobalt in the leachate under the promotion of chloroacetic acid to form a cobalt and manganese betaine hydrochloride chelate. The chelate is redissolved in water, and the difference in solubility constants of cobalt oxalate and manganese oxalate under acidic conditions is utilized to separate cobalt and manganese using anhydrous oxalic acid. As for the nickel in the leachate, anhydrous oxalic acid is added to generate nickel oxalate precipitation, thereby achieving the purpose of separation.

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

[0024] (1) The present invention uses a deep eutectic solvent synthesized from chloroacetic acid and betaine hydrochloride to achieve efficient leaching of valuable metals in the positive electrode materials of waste ternary lithium batteries, avoiding the use of strong acids and strong bases, and having good environmental benefits.

[0025] (2) The present invention adds anhydrous ethanol to change the environment of the leaching solution, thereby realizing the step-by-step recovery of valuable metals. Compared with extraction, direct chemical precipitation and other methods, the present invention has higher selectivity, less consumption of chemical reagents, and lower economic cost. Excess anhydrous ethanol can be reused by distillation.

[0026] (3) The recovery process provided by the present invention can efficiently and selectively separate and recover a variety of valuable metal elements, and the recovered products have higher value. In addition, the use of a large amount of inorganic salt precipitants is avoided during the recovery process, thereby reducing the generation of saline wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0029] Example 1

[0030] After mixing chloroacetic acid and betaine hydrochloride in a molar ratio of 3:1, 30wt% water of the total mass of chloroacetic acid and betaine hydrochloride was added, and heated in a water bath at 80°C for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol: leachate of 11:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added according to the molar ratio of oxalic acid to cobalt in solution 2 of 2.5:1, and the pH value of the solution was adjusted to 2.5 with ammonia water and then heated in a water bath at 60°C for 1 hour. Cobalt oxalate precipitate and solution 3 containing manganese were obtained by filtration and separation. The pH value of solution 3 was adjusted to 12, and the manganese in solution 3 was precipitated in the form of hydroxide, which was separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt and manganese were 97.52%, 95.11% and 93.68% respectively.

[0031] Example 2

[0032] After mixing chloroacetic acid and betaine hydrochloride in a molar ratio of 2:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C and stirred for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C and stirred for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 11:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added according to the molar ratio of oxalic acid to cobalt in solution 2 of 2.5:1, and the pH value of the solution was adjusted to 2.5 with ammonia water and heated in a water bath at 60°C for 1 hour. Cobalt oxalate precipitate and solution 3 containing manganese were obtained by filtration and separation. The pH value of solution 3 was adjusted to 12, and the manganese in solution 3 was precipitated in the form of hydroxide, which was separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt, and manganese were 91.43%, 89.22%, and 87.28%, respectively.

[0033] Example 3

[0034] After mixing chloroacetic acid and betaine hydrochloride in a molar ratio of 4:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C and stirred for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C and stirred for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 11:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added according to the molar ratio of oxalic acid to cobalt in solution 2 of 2.5:1, and the pH value of the solution was adjusted to 2.5 with ammonia water and then heated in a water bath at 60°C for 1 hour. Cobalt oxalate precipitate and solution 3 containing manganese were obtained by filtration and separation. The pH value of solution 3 was adjusted to 12, and the manganese in solution 3 was precipitated in the form of hydroxide, which was separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt, and manganese were 90.12%, 86.91%, and 89.67%, respectively.

[0035] Example 4

[0036] After mixing chloroacetic acid and betaine hydrochloride in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C and stirred for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 80°C and stirred for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 11:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added according to the molar ratio of oxalic acid to cobalt in solution 2 of 2.5:1, and the pH value of the solution was adjusted to 2.5 with ammonia water and heated in a water bath at 60°C for 1 hour. Cobalt oxalate precipitate and solution 3 containing manganese were obtained by filtration and separation. The pH value of solution 3 was adjusted to 12, and the manganese in solution 3 was precipitated in the form of hydroxide, which was separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt, and manganese were 77.71%, 71.34%, and 69.28%, respectively.

[0037] Example 5

[0038] After mixing chloroacetic acid and betaine hydrochloride in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C and stirred for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 85°C and stirred for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 11:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added according to the molar ratio of oxalic acid to cobalt in solution 2 of 2.5:1, and the pH value of the solution was adjusted to 2.5 with ammonia water and then heated in a water bath at 60°C for 1 hour. Cobalt oxalate precipitate and solution 3 containing manganese were obtained by filtration and separation. The pH value of solution 3 was adjusted to 12, and the manganese in solution 3 was precipitated in the form of hydroxide, which was separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt, and manganese were 86.61%, 84.34%, and 83.65%, respectively.

[0039] Example 6

[0040] After mixing chloroacetic acid and betaine hydrochloride in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C and stirred for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 95°C and stirred for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 11:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added according to the molar ratio of oxalic acid to cobalt in solution 2 of 2.5:1, and the pH value of the solution was adjusted to 2.5 with ammonia water and heated in a water bath at 60°C for 1 hour. Cobalt oxalate precipitate and solution 3 containing manganese were obtained by filtration and separation. The pH value of solution 3 was adjusted to 12, and the manganese in solution 3 was precipitated in the form of hydroxide, which was separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt, and manganese were 97.43%, 95.32%, and 92.98%, respectively.

[0041] Example 7

[0042] After mixing chloroacetic acid and betaine hydrochloride in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C and stirred for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C and stirred for 1h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 11:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added according to the molar ratio of oxalic acid to cobalt in solution 2 of 2.5:1, and the pH value of the solution was adjusted to 2.5 with ammonia water and then heated in a water bath at 60°C for 1 hour. Cobalt oxalate precipitate and solution 3 containing manganese were obtained by filtration and separation. The pH value of solution 3 was adjusted to 12, and the manganese in solution 3 was precipitated in the form of hydroxide, which was separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt, and manganese were 67.38%, 52.34%, and 56.72%, respectively.

[0043] Example 8

[0044] After mixing chloroacetic acid and betaine hydrochloride in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C and stirred for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C and stirred for 3h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 11:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added according to the molar ratio of oxalic acid to cobalt in solution 2 of 2.5:1, and the pH value of the solution was adjusted to 2.5 with ammonia water and then heated in a water bath at 60°C for 1 hour. Cobalt oxalate precipitate and solution 3 containing manganese were obtained by filtration and separation. The pH value of solution 3 was adjusted to 12, and the manganese in solution 3 was precipitated in the form of hydroxide, which was separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt, and manganese were 96.82%, 94.61%, and 93.55%, respectively.

[0045] Example 9

[0046] After mixing chloroacetic acid and betaine hydrochloride in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 5g / L, and the mixture was heated in a water bath at 90°C for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 11:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added according to the molar ratio of oxalic acid to cobalt in solution 2 of 2.5:1, and the pH value of the solution was adjusted to 2.5 with ammonia water and then heated in a water bath at 60°C for 1 hour. Cobalt oxalate precipitate and solution 3 containing manganese were obtained by filtration and separation. The pH value of solution 3 was adjusted to 12, and the manganese in solution 3 was precipitated in the form of hydroxide, which was separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt, and manganese were 97.28%, 96.3%, and 93.17%, respectively.

[0047] Example 10

[0048] After mixing chloroacetic acid and betaine hydrochloride in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C and stirred for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 15g / L, and the mixture was heated in a water bath at 90°C and stirred for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 11:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added according to the molar ratio of oxalic acid to cobalt in solution 2 of 2.5:1, and the pH value of the solution was adjusted to 2.5 with ammonia water and then heated in a water bath at 60°C for 1 hour. Cobalt oxalate precipitate and solution 3 containing manganese were obtained by filtration and separation. The pH value of solution 3 was adjusted to 12, and the manganese in solution 3 was precipitated in the form of hydroxide, which was separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt, and manganese were 88.65%, 84.39%, and 80.92%, respectively.

[0049] Embodiment 11

[0050] After mixing chloroacetic acid and betaine hydrochloride in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C and stirred for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 20g / L, and the mixture was heated in a water bath at 90°C and stirred for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 11:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added according to the molar ratio of oxalic acid to cobalt in solution 2 of 2.5:1, and the pH value of the solution was adjusted to 2.5 with ammonia water and heated in a water bath at 60°C for 1 hour. Cobalt oxalate precipitate and solution 3 containing manganese were obtained by filtration and separation. The pH value of solution 3 was adjusted to 12, and the manganese in solution 3 was precipitated in the form of hydroxide, which was separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt, and manganese were 72.52%, 65.49%, and 64.39%, respectively.

[0051] Example 12

[0052] After mixing chloroacetic acid and betaine hydrochloride in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C and stirred for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C and stirred for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 9:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added according to the molar ratio of oxalic acid to cobalt in solution 2 of 2.5:1, and the pH value of the solution was adjusted to 2.5 with ammonia water and heated in a water bath at 60°C for 1 hour. Cobalt oxalate precipitate and solution 3 containing manganese were obtained by filtration and separation. The pH value of solution 3 was adjusted to 12, and the manganese in solution 3 was precipitated in the form of hydroxide, which was separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt, and manganese were 98.1%, 79.69%, and 78.47%, respectively.

[0053] Example 13

[0054] After mixing chloroacetic acid and betaine hydrochloride in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C and stirred for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C and stirred for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 10:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added according to the molar ratio of oxalic acid to cobalt in solution 2 of 2.5:1, and the pH value of the solution was adjusted to 2.5 with ammonia water and then heated in a water bath at 60°C for 1 hour. Cobalt oxalate precipitate and solution 3 containing manganese were obtained by filtration and separation. The pH value of solution 3 was adjusted to 12, and the manganese in solution 3 was precipitated in the form of hydroxide, which was separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt, and manganese were 97.56%, 84.52%, and 83.66%, respectively.

[0055] Embodiment 14

[0056] After mixing chloroacetic acid and betaine hydrochloride in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C and stirred for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C and stirred for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 12:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added according to the molar ratio of oxalic acid to cobalt in solution 2 of 2.5:1, and the pH value of the solution was adjusted to 2.5 with ammonia water and then heated in a water bath at 60°C for 1 hour. Cobalt oxalate precipitate and solution 3 containing manganese were obtained by filtration and separation. The pH value of solution 3 was adjusted to 12, and the manganese in solution 3 was precipitated in the form of hydroxide, which was separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt, and manganese were 96.92%, 92.81%, and 89.69%, respectively.

[0057] Embodiment 15

[0058] After chloroacetic acid and betaine hydrochloride were mixed in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol: leachate of 11:1, and stirred at room temperature for 2h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added at a molar ratio of oxalic acid to cobalt in solution 2 of 2.5:1, and the solution pH was adjusted to 2.5 with ammonia water and heated in a water bath at 60°C for 1h. Cobalt oxalate precipitate and solution 3 containing manganese are obtained by filtration and separation. The pH value of solution 3 is adjusted to 12, and manganese in solution 3 is precipitated in the form of hydroxide, which is separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt and manganese are 97.28%, 87.29% and 84.95% respectively.

[0059] Example 16

[0060] After chloroacetic acid and betaine hydrochloride were mixed in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol: leachate of 11:1, and stirred at room temperature for 3h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added at a molar ratio of oxalic acid to cobalt in solution 2 of 2.5:1, and the solution pH was adjusted to 2.5 with ammonia water and heated in a water bath at 60°C for 1h. Cobalt oxalate precipitate and solution 3 containing manganese are obtained by filtration and separation. The pH value of solution 3 is adjusted to 12, and manganese in solution 3 is precipitated in the form of hydroxide, which is separated by filtration to obtain manganese hydroxide. The recovery rates of nickel, cobalt and manganese are calculated to be 96.9%, 94.21% and 90.28% respectively.

[0061] Embodiment 17

[0062] After chloroacetic acid and betaine hydrochloride were mixed in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol: leachate of 11:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added at a molar ratio of oxalic acid to cobalt in solution 2 of 2:1, and the solution pH was adjusted to 2.5 with ammonia water and heated in a water bath at 60°C for 1h. Cobalt oxalate precipitate and solution 3 containing manganese are obtained by filtration and separation. The pH value of solution 3 is adjusted to 12, and manganese in solution 3 is precipitated in the form of hydroxide, which is separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt and manganese are 97.26%, 90.19% and 93.38% respectively.

[0063] Embodiment 18

[0064] After chloroacetic acid and betaine hydrochloride were mixed in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 11:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added at a molar ratio of oxalic acid to cobalt in solution 2 of 3:1, and the solution pH was adjusted to 2.5 with ammonia water and heated in a water bath at 60°C for 1h. Cobalt oxalate precipitate and solution 3 containing manganese are obtained by filtration and separation. The pH value of solution 3 is adjusted to 12, and manganese in solution 3 is precipitated in the form of hydroxide, which is separated by filtration to obtain manganese hydroxide. The recovery rates of nickel, cobalt and manganese are calculated to be 97.71%, 96.1% and 88.25% respectively.

[0065] Embodiment 19

[0066] After chloroacetic acid and betaine hydrochloride were mixed in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 11:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added at a molar ratio of oxalic acid to cobalt in solution 2 of 3:1, and the solution pH was adjusted to 2 with ammonia water and heated in a water bath at 60°C for 1h. Cobalt oxalate precipitate and solution 3 containing manganese are obtained by filtration and separation. The pH value of solution 3 is adjusted to 12, and manganese in solution 3 is precipitated in the form of hydroxide, which is separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt and manganese are 97.56%, 86.1% and 94.23% respectively.

[0067] Embodiment 20

[0068] After chloroacetic acid and betaine hydrochloride were mixed in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 11:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added at a molar ratio of oxalic acid to cobalt in solution 2 of 3:1, and the solution pH was adjusted to 3 with ammonia water and heated in a water bath at 60°C for 1h. Cobalt oxalate precipitate and solution 3 containing manganese are obtained by filtration and separation. The pH value of solution 3 is adjusted to 12, and manganese in solution 3 is precipitated in the form of hydroxide, which is separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt and manganese are 96.42%, 95.99% and 89.74% respectively.

[0069] Comparative Example 1

[0070] After formic acid and betaine hydrochloride were mixed in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C for 30min to form C-DES. Subsequently, it was mixed with SNCM positive electrode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C for 2h. After leaching, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol:leachate of 11:1, and stirred at room temperature for 2.5h. Cobalt, manganese betaine hydrochloride chelate and nickel-containing solution 1 were obtained by filtration and separation. Anhydrous oxalic acid was added to solution 1 at a molar ratio of nickel to anhydrous oxalic acid of 1:1 to form a nickel oxalate precipitate, and the nickel oxalate product was obtained by filtration and separation. Subsequently, the formed cobalt and manganese betaine hydrochloride chelate was dissolved in water at a solid-liquid ratio of 10g / L to obtain solution 2. Anhydrous oxalic acid was added at a molar ratio of oxalic acid to cobalt in solution 2 of 3:1, and the solution pH was adjusted to 3 with ammonia water and heated in a water bath at 60°C for 1h. Cobalt oxalate precipitate and solution 3 containing manganese are obtained by filtration and separation. The pH value of solution 3 is adjusted to 12, and manganese in solution 3 is precipitated in the form of hydroxide, which is separated by filtration to obtain manganese hydroxide. After calculation, the recovery rates of nickel, cobalt and manganese are 58.43%, 28.49% and 44.57% respectively.

[0071] Comparative Example 2

[0072] After chloroacetic acid and tetrabutylammonium chloride were mixed in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C and stirred for 30 minutes to form C-DES. Subsequently, it was mixed with SNCM cathode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C and stirred for 2h. After the leaching was completed, anhydrous ethanol was added to the leachate at a volume ratio of anhydrous ethanol: leachate of 11:1, and stirred for 2.5h at room temperature. It was observed that no precipitation was generated in the solution, which confirmed that it was difficult to recover nickel, cobalt and manganese in the cathode material of waste ternary lithium batteries by the technical solution of the present invention using tetrabutylammonium chloride as a hydrogen bond acceptor.

[0073] Comparative Example 3

[0074] After mixing chloroacetic acid and betaine hydrochloride in a molar ratio of 3:1, 30wt% water was added, and the mixture was heated in a water bath at 80°C and stirred for 30 minutes to form C-DES. Subsequently, it was mixed with SNCM cathode material powder at a solid-liquid ratio of 10g / L, and the mixture was heated in a water bath at 90°C and stirred for 2h. After the leaching was completed, anhydrous oxalic acid was directly added to the leachate, and precipitation was observed. The recovery rates of nickel, cobalt, and manganese were 88.23%, 48.36%, and 71.25%, respectively. Although the direct addition of anhydrous oxalic acid solution will obtain precipitation products of nickel, cobalt, and manganese, nickel, cobalt, and manganese are precipitated together, and selective separation is not achieved and the precipitation efficiency is poor.

[0075] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for selectively recovering nickel, cobalt and manganese from waste ternary lithium battery positive electrode materials by deep eutectic solvent, characterized in that: The method steps are as follows: (1) Chloroacetic acid and betaine hydrochloride were mixed in a molar ratio, 30 wt % of water was added as a co-solvent, and the mixture was then heated and stirred in a water bath at 80° C. for 30 min. The obtained deep eutectic solvent was recorded as C-DES; (2) After the SNCM cathode material powder and C-DES are uniformly mixed, the mixture is heated in a water bath and stirred for leaching. After the leaching is completed, the mixed solution is filtered through a 0.22 μm PTFE filter membrane to obtain a leachate; (3) adding anhydrous ethanol to the leaching solution obtained in step (2), stirring at room temperature to generate manganese and cobalt betaine hydrochloride chelate crystals, and separating by filtration to obtain manganese and cobalt betaine hydrochloride chelate and a nickel-containing solution 1; (4) adding anhydrous oxalic acid to solution 1 to form nickel oxalate, and separating by filtration to obtain nickel oxalate precipitate; re-dissolving the obtained cobalt and manganese betaine hydrochloride chelate in water at a solid-liquid ratio of 10 g / L to obtain solution 2 containing cobalt and manganese; (5) adding anhydrous oxalic acid to solution 2 and adjusting the pH value of the solution with aqueous ammonia, then heating the solution in a water bath to form a cobalt oxalate precipitate, filtering and separating to obtain the cobalt oxalate precipitate and the manganese-containing solution 3; adjusting the pH value of the manganese-containing solution 3 with aqueous ammonia to form a manganese hydroxide precipitate, filtering and obtaining the manganese hydroxide precipitate.

2. The method for selectively recovering nickel, cobalt and manganese from waste ternary lithium battery positive electrode materials by deep eutectic solvent according to claim 1, characterized in that: In step (1), the molar ratio of chloroacetic acid to betaine hydrochloride is 2 to 4:

1.

3. The method for selectively recovering nickel, cobalt and manganese from waste ternary lithium battery positive electrode materials by deep eutectic solvent according to claim 1, characterized in that: In step (2), the solid-liquid ratio of SNCM positive electrode material powder to C-DES is 5 g / L to 20 g / L.

4. The method for selectively recovering nickel, cobalt and manganese from waste ternary lithium battery positive electrode materials by deep eutectic solvent according to claim 1, characterized in that: In step (2), the water bath heating stirring temperature is 80°C to 95°C, the time is 1h to 3h, and the stirring rate is 500rpm.

5. The method for selectively recovering nickel, cobalt and manganese from waste ternary lithium battery positive electrode materials by deep eutectic solvent according to claim 1, characterized in that: In step (3), the volume ratio of the added anhydrous ethanol to the leaching solution is 9-12:1, the stirring time is 2h-3h, and the stirring rate is 350rpm.

6. The method for selectively recovering nickel, cobalt and manganese from waste ternary lithium battery positive electrode materials by deep eutectic solvent according to claim 1, characterized in that: In step (4), the molar ratio of the added anhydrous oxalic acid to the nickel in solution 1 is 1:

1.

7. The method for selectively recovering nickel, cobalt and manganese from waste ternary lithium battery positive electrode materials by deep eutectic solvent according to claim 1, characterized in that: In step (5), the molar ratio of the added anhydrous oxalic acid to the cobalt in solution 2 is 2-3:1, the pH value of solution 2 is adjusted to 2-3, the water bath temperature is 60° C., and the water bath time is 1 h.

8. The method for selectively recovering nickel, cobalt and manganese from waste ternary lithium battery positive electrode materials by deep eutectic solvent according to claim 1, characterized in that: In step (5), the pH value of solution 3 is adjusted to 12.

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