Method for recovering valuable metal in battery by adopting eutectic solvent

Abstract

The invention discloses a method for recovering valuable metals in a battery by using a eutectic solvent, and relates to the technical field of batteries, and the method comprises the following steps: preparing the eutectic solvent by using a hydrogen bond acceptor, a hydrogen bond donor and deionized water; obtaining a waste battery positive electrode material, dispersing the waste battery positive electrode material in the eutectic solvent, stirring and leaching, and then carrying out solid-liquid separation to obtain a leachate and a coprecipitate; adding a first acid solution into the leaching solution to obtain a lithium metal leaching solution, evaporating and concentrating the lithium metal leaching solution, and adding the lithium metal leaching solution into the eutectic solvent; and adding a second acid solution into the coprecipitate, separating to obtain a cobalt precipitate and a manganese metal leaching solution, and adding an alkali solution into the manganese metal leaching solution to obtain a manganese precipitate. According to the method, the valuable metals in the battery positive electrode material are leached under the mild condition, so that the valuable metals are separated one by one.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and in particular to a method for recovering valuable metals in batteries by using a low eutectic solvent. Background Art

[0002] A low eutectic solvent is a special solvent composed of different components in a specific proportion. It is mainly used in the fields of materials and chemistry. In the field of materials science, it can be used to prepare composite materials and nanomaterials. In the field of organic synthesis, it can act as a catalyst, catalytic carrier or reaction medium. In the field of drug synthesis, low eutectic solvents can effectively separate drug components and impurities. In the field of electrochemistry, it serves as an important raw material for the preparation of electrolytes and flow batteries.

[0003] In some related technologies, low eutectic solvents are used to leach metal materials in batteries. Although nickel, cobalt, manganese and lithium in the materials can be leached out, the metal substances are still mixed together after leaching and cannot be separated. At the same time, the metal nickel in ternary lithium batteries has a higher metal content than lithium, cobalt and manganese, and existing selective metals cannot effectively recover the metal nickel in waste ternary lithium batteries. Summary of the invention

[0004] In order to solve at least one of the problems mentioned in the above background technology, the present application provides a method for recovering valuable metals in batteries using a low eutectic solvent, by adjusting the ratio of hydrogen bond donors to hydrogen bond acceptors to achieve the leaching of valuable metals in the battery positive electrode material under mild conditions, and then using a precipitation process to effectively regenerate the ternary positive electrode precursor, thereby achieving the separation of each valuable metal in the battery one by one.

[0005] The specific technical solutions provided by the embodiments of this application are as follows:

[0006] A method for recovering valuable metals in a battery using a deep eutectic solvent is provided, the method comprising:

[0007] A deep eutectic solvent is prepared by using a hydrogen bond acceptor, a hydrogen bond donor and a dispersant;

[0008] Obtaining a waste battery positive electrode material, dispersing the waste battery positive electrode material in the low eutectic solvent, stirring and leaching, and then performing solid-liquid separation to obtain a leachate and a coprecipitate;

[0009] adding a first acid solution to the leachate to obtain a lithium metal leachate, evaporating and concentrating the lithium metal leachate and adding the resultant to the deep eutectic solvent;

[0010] A second acid solution is added to the coprecipitate to separate a cobalt precipitate and a manganese metal leaching solution, and an alkali solution is added to the manganese metal leaching solution to obtain a manganese precipitate.

[0011] In a specific embodiment, the lithium metal leaching solution is treated by evaporation concentration or addition of a preset acid solution to obtain a supplementary solvent, and the supplementary solvent is added to the low eutectic solvent for cyclic use.

[0012] In a specific embodiment, the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is (1:0.5) to (1:10).

[0013] In a specific embodiment, the hydrogen bond acceptor is one of choline chloride, betaine, and betaine hydrochloride; and / or the hydrogen bond donor is citric acid.

[0014] In a specific embodiment, the dispersant is configured as deionized water, and after adding the deionized water, heating and stirring are performed at a heating temperature of 25 to 95° C. and stirring is performed for 15 to 120 minutes to obtain the low eutectic solvent.

[0015] In a specific embodiment, the stirring leaching temperature is 25 to 120° C., and the stirring leaching time is 15 to 360 minutes.

[0016] In a specific embodiment, the solid-liquid mass ratio of the waste battery positive electrode material to the low eutectic solvent is (0.7:20) to (2.5:20).

[0017] In a specific embodiment, the first acid solution is configured as a saturated oxalic acid solution, and the molar ratio of the nickel metal in the leachate to the saturated oxalic acid solution is 1:(1.1-1.6).

[0018] In a specific embodiment, the second acid solution is configured as an oxalic acid solution, and the concentration of the oxalic acid solution is configured to be 0.15-1.5 mol / L.

[0019] In a specific embodiment, the liquid-to-solid ratio of the second acid solution to the coprecipitate is 1:(1-10) mL / g.

[0020] In a specific embodiment, an alkaline solution is added to the manganese metal leaching solution, and the pH of the manganese metal leaching solution is adjusted to 8-12, and the concentration of the alkaline solution is 1.2-3 mol / L.

[0021] In a specific embodiment, the cobalt precipitate and the manganese precipitate are calcined to obtain metal oxides.

[0022] In a specific embodiment, the positive electrode material of the waste battery is selected from one or more of nickel cobalt manganese oxide 622, nickel cobalt manganese oxide 811 or nickel cobalt manganese oxide 523.

[0023] The embodiments of the present application have the following beneficial effects:

[0024] 1. The solution provided in the embodiment of the present application adjusts the ratio of hydrogen bond donors to hydrogen bond acceptors to achieve the leaching of valuable metals in the positive electrode material of the battery under mild conditions, and adjusts the critical point of leaching using a low eutectic solvent, while increasing the amount of lemon added, increasing the compounding temperature and time, and adjusting the leaching temperature and leaching time to achieve selective leaching of lithium and nickel into the leachate, and leaching of cobalt and manganese into the co-precipitate in the form of precipitation.

[0025] 2. In the process of leaching metals using a low eutectic solvent, high-valent transition metal ions undergo a reduction reaction to generate low-valent transition metal ions, and the structure of the active substances in the positive electrode material of the battery is destroyed, thereby achieving the leaching of valuable metals into the solution. Organic acids that can be used as hydrogen bond donors include malic acid, acetic acid, ascorbic acid, oxalic acid, etc. Organic acids such as malic acid, acetic acid, and ascorbic acid cannot form precipitation with valuable metals during the leaching process, and are commonly used for full-component leaching of metals, and then use separation processes to extract valuable metals one by one. When oxalic acid is used as a hydrogen bond donor, the reaction process produces coprecipitation of nickel, cobalt, manganese, and a small amount of lithium, which is not conducive to the subsequent separation of metals one by one. This application uses citric acid as a hydrogen bond donor. As the reaction proceeds, the hydrogen bond donor citric acid forms citrate, and citrate and citric acid form cobalt citrate and manganese citrate precipitation with cobalt oxide, manganese oxide, and manganese chloride in the leachate, thereby achieving selective separation of cobalt and manganese.

[0026] 3. When leaching nickel and lithium into the leachate through the low eutectic solvent, the oxalic acid solution is added to separate the nickel oxalate from the lithium-rich leachate. The oxalic acid solution is added to the co-precipitate to separate the solid and liquid to obtain a manganese-rich leachate and a cobalt oxalate precipitate, thereby realizing the separation of the valuable metals in the ternary positive electrode. The lithium-rich solution is recycled as a low eutectic solvent, and at the same time, each valuable metal in the battery is separated one by one. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 A schematic diagram of a method for recovering valuable metals in batteries using a deep eutectic solvent according to the present application is shown. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0031] In one embodiment, a method for recovering valuable metals in batteries using a deep eutectic solvent is provided, such as Figure 1 As shown, the following steps are included:

[0032] Step 1: prepare a low eutectic solvent using a hydrogen bond acceptor, a hydrogen bond donor and a dispersant.

[0033] Specifically, the hydrogen bond acceptor and the hydrogen bond donor are placed in a beaker, mixed to form a mixed solvent, and then a dispersant is added to the mixed solvent. The beaker is sealed with a plastic wrap and stirred at a preset temperature to obtain a transparent and uniform low eutectic solvent. The dispersant in this embodiment is deionized water. Specifically, a certain amount of deionized water is added and heated and stirred at a heating temperature of 25 to 95° C. and stirred for 15 to 120 minutes to obtain the low eutectic solvent.

[0034] The hydrogen bond acceptor includes but is not limited to one of choline chloride, betaine and betaine hydrochloride, and the hydrogen bond donor is citric acid.

[0035] In this embodiment, the molar ratio of the hydrogen bond acceptor and the hydrogen bond donor is set to (1:0.5) to (1:10); the molar ratio of the hydrogen bond acceptor and the hydrogen bond donor is further set to (1:1.5) to (1:8), specifically, the molar ratio of the hydrogen bond acceptor and the hydrogen bond donor is set to 2:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:5, 1:6.5, 1:7.5 or 1:8.

[0036] Further, the mass percentage of deionized water in the deep eutectic solvent in this embodiment is 20-40wt%. The mass percentage of deionized water in the deep eutectic solvent in this embodiment is 25-35wt%. Specifically, the mass percentage of deionized water in the deep eutectic solvent is 25wt%, 30wt%, 35wt% or 40wt%.

[0037] Step 2: obtaining the positive electrode material of the waste battery, dispersing the positive electrode material of the waste battery in the low eutectic solvent, stirring and leaching, and then performing solid-liquid separation to obtain a leachate and a coprecipitate.

[0038] According to the solid-liquid mass volume ratio of the waste battery positive electrode material and the low eutectic solvent, the corresponding mass of the waste battery material is weighed into a conical flask, and the low eutectic solvent is added for stirring and leaching, the leaching temperature is 25-120°C, and the leaching stirring time is 15-360min, so as to obtain a leachate and a coprecipitate. In this way, lithium and nickel metals in the waste ternary lithium battery positive electrode material are leached by the low eutectic solvent, and lithium and nickel are extracted into the leachate, and other metals cobalt and manganese are present in the coprecipitate in the form of cobalt citrate, manganese citrate and oxide, respectively.

[0039] Wherein, the solid-liquid mass ratio of the waste battery positive electrode material to the low eutectic solvent is (0.7:20) to (2.5:20). Specifically, the solid-liquid mass ratio of the waste battery positive electrode material to the low eutectic solvent is 1:20, 1.2:20, 1.5:20, 1.8:20, 1.9:20, 2.0:20, 2.1:20, 2.1:20, 2.2:20, 2.3:20, 2.4:20 or 2.5:20.

[0040] In the embodiment, the waste battery is selected as a waste ternary battery, wherein the positive electrode material of the waste battery is configured as one or more of nickel cobalt lithium manganese oxide 622, nickel cobalt lithium manganese oxide 811 or nickel cobalt lithium manganese oxide 523.

[0041] Step 3: adding the first acid solution to the leachate to obtain a lithium metal leachate and a nickel precipitate, evaporating and concentrating the lithium metal leachate and adding it to the low eutectic solvent.

[0042] Specifically, a first acid solution is added to the leachate, the first acid solution is configured as a saturated oxalic acid solution, the reaction temperature is set to 60-70°C, and after the reaction is completed, the nickel oxalate precipitate is filtered and dried. The lithium metal leachate is further evaporated and concentrated or a preset acid solution is added to treat the lithium metal leachate to obtain a supplementary solvent, and the supplementary solvent is added to the low eutectic solvent for recycling. The preset acid solution can be configured as citric acid.

[0043] Specifically, the concentration of the saturated oxalic acid solution at room temperature is 540 g / L. The molar ratio of the nickel metal in the leachate to the saturated oxalic acid solution is 1:(1.1-1.6), and specifically, the molar ratio of the nickel metal in the leachate to the saturated oxalic acid solution is 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5 or 1:1.6.

[0044] Step 4: adding a second acid solution to the coprecipitate to separate a cobalt precipitate and a manganese metal leaching solution, and adding an alkaline solution to the manganese metal leaching solution to obtain a manganese precipitate.

[0045] Wherein, the second acid solution is configured as an oxalic acid solution, and the concentration of the oxalic acid solution is configured to be 0.15-1.5 mol / L. Wherein, the liquid-to-solid ratio of the second acid solution to the coprecipitate is 1:(1-10) mL / g. Specifically, the liquid-to-solid ratio of the oxalic acid solution to the coprecipitate is 1:1 mL / g, 1:2 mL / g, 1:3 mL / g, 1:4 mL / g, 1:5 mL / g, 1:6 mL / g, 1:7 mL / g, 1:8 mL / g, 1:9 mL / g or 1:10 mL / g.

[0046] After adding the oxalic acid solution, the reaction is carried out at a temperature of 40 to 60° C. to separate the cobalt precipitate and the manganese metal leaching solution, and an alkali solution is added to the manganese metal leaching solution, and the pH of the manganese metal leaching solution is adjusted to 8 to 12, and the concentration of the alkali solution is 1.2 to 3 mol / L.

[0047] Specifically, the alkaline solution is configured as one of a sodium hydroxide solution, a potassium hydroxide solution or a barium hydroxide solution.

[0048] After obtaining the nickel precipitate, the cobalt precipitate and the manganese precipitate, the precipitates are calcined to obtain corresponding metal oxides.

[0049] Through the above scheme, this embodiment adjusts the ratio of hydrogen bond donors to hydrogen bond acceptors to achieve the leaching of valuable metals in the battery positive electrode material under mild conditions, and adjusts the critical point of leaching using a low eutectic solvent, while increasing the amount of lemon added, increasing the compounding temperature and time, and adjusting the leaching temperature and leaching time to achieve selective leaching of lithium and nickel into the leachate, and leaching of cobalt and manganese into the co-precipitate in the form of precipitation.

[0050] Example 1

[0051] Corresponding to the above embodiment, this embodiment provides a method for recovering valuable metals in batteries using a deep eutectic solvent, and the specific preparation process is as follows:

[0052] A hydrogen bond acceptor, choline chloride, and a hydrogen bond donor, citric acid, are placed in a beaker, wherein the molar ratio of choline chloride to citric acid is set to 1:6, 35%wt of deionized water is added, the beaker is sealed with plastic wrap, and stirred at room temperature to obtain a transparent and uniform low eutectic solvent;

[0053] The solid-liquid mass ratio of the waste battery positive electrode material to the low eutectic solvent was configured to be 1.5:20, 1.5 g of the waste ternary battery positive electrode material (the positive electrode material is NCM523) was weighed and stirred in a conical flask for leaching, 20 g of the low eutectic solvent was added, the leaching temperature was set to 80 ° C, and the leaching time was 30 min to obtain a leachate and a coprecipitate;

[0054] A saturated oxalic acid solution is respectively prepared as the first acid solution and the oxalic acid solution is prepared as the second acid solution, and the saturated oxalic acid solution is added to the leachate, wherein the molar ratio of the nickel metal in the leachate to the saturated oxalic acid solution is 1:1.1, and after the reaction is completed, a lithium metal leachate and a nickel precipitate are obtained;

[0055] An oxalic acid solution was added to the coprecipitate, the concentration of the oxalic acid solution was 0.5 mol / L, the reaction temperature was 80° C., the reaction time was 60 min, and after the reaction, a cobalt precipitate and a manganese metal leaching solution were obtained. A sodium hydroxide solution was added to the manganese metal leaching solution to obtain a manganese precipitate.

[0056] After testing the above separated substances, it was found that after leaching with the low eutectic solvent, the leaching rate of Li was 90.46%, the leaching rate of Ni was 81.73%, the leaching rate of Co was 28.52%, and the leaching rate of Mn was 23.46%. After recovery treatment by the first acid solution and the second acid solution, the selective recovery rates of Li, Mn, Co and Ni were 93.2%, 93.3%, 89.5% and 91.1%, respectively.

[0057] Example 2

[0058] Corresponding to the above embodiment, this embodiment provides a method for recovering valuable metals in batteries using a low eutectic solvent. The difference between this embodiment and Example 1 is that the molar ratio of choline chloride to citric acid is 1:1.5, and the leaching time is 90 minutes.

[0059] After testing the above separated substances, the leaching rate of Li was 96.23%, the leaching rate of Ni was 93.76%, the leaching rate of Co was 32.63%, and the leaching rate of Mn was 24.43%. After recovery treatment by the first acid solution and the second acid solution, the selective recovery rates of Li, Mn, Co and Ni were all above 85%.

[0060] Example 3

[0061] Corresponding to the above embodiment, this embodiment proposes a method for recovering valuable metals in batteries using a deep eutectic solvent, and the specific preparation process is as follows:

[0062] Put choline chloride and citric acid in a beaker, set the molar ratio of choline chloride to citric acid to be 1:2, add 35%wt deionized water, seal the beaker with plastic wrap, heat to 80°C and stir to obtain a transparent and uniform low eutectic solvent;

[0063] The solid-liquid mass ratio of the waste battery positive electrode material and the low eutectic solvent was configured to be 0.75:20, 0.75 g of the waste ternary battery positive electrode material (the positive electrode material is NCM811) was weighed and stirred in a conical flask for leaching, 20 g of the low eutectic solvent was added, the leaching temperature was set to 80 ° C, the leaching time was 120 min, and the leachate and coprecipitate were obtained;

[0064] A saturated oxalic acid solution is respectively prepared as the first acid solution and the oxalic acid solution is prepared as the second acid solution, and the saturated oxalic acid solution is added to the leachate, wherein the molar ratio of the nickel metal in the leachate to the saturated oxalic acid solution is 1:1.1, and after the reaction is completed, a lithium metal leachate and a nickel precipitate are obtained;

[0065] An oxalic acid solution was added to the coprecipitate, the concentration of the oxalic acid solution was 0.5 mol / L, the reaction temperature was 80° C., the reaction time was 60 min, and after the reaction, a cobalt precipitate and a manganese metal leaching solution were obtained. A sodium hydroxide solution was added to the manganese metal leaching solution to obtain a manganese precipitate.

[0066] After testing the above separated substances, when the compounding temperature is increased from room temperature to 80°C, after leaching with a low eutectic solvent (DESs), the leaching rate of Li is 97.22%; the leaching rate of Ni is 81.73%, the leaching rate of Co is 13.29%, and the leaching rate of Mn is 2.74%. As the compounding temperature increases, the leaching rates of lithium and nickel gradually increase, while the leaching rates of cobalt and manganese gradually decrease. After recovery treatment by the first acid solution and the second acid solution, the selective recovery rates of Li, Mn, Co and Ni are all above 85%.

[0067] Example 4

[0068] Corresponding to the above embodiment, this embodiment provides a method for recovering valuable metals in batteries using a deep eutectic solvent, and the specific preparation process is as follows:

[0069] Betaine hydrochloride and citric acid are placed in a beaker, the molar ratio of betaine hydrochloride to citric acid is set to 1:5, 35%wt of deionized water is added, the beaker is sealed with plastic wrap, and stirred under heating to 50°C to obtain a transparent and uniform low eutectic solvent;

[0070] The solid-liquid mass ratio of the waste battery positive electrode material to the low eutectic solvent was configured to be 1.5:20, 1.5 g of the waste ternary battery positive electrode material (the positive electrode material is NCM622) was weighed and stirred in a conical flask for leaching, 20 g of the low eutectic solvent was added, the leaching temperature was set to 80 ° C, the leaching time was 60 min, and a leachate and a coprecipitate were obtained;

[0071] A saturated oxalic acid solution is respectively prepared as the first acid solution and the oxalic acid solution is prepared as the second acid solution, and the saturated oxalic acid solution is added to the leachate, wherein the molar ratio of the nickel metal in the leachate to the saturated oxalic acid solution is 1:1.1, and after the reaction is completed, a lithium metal leachate and a nickel precipitate are obtained;

[0072] An oxalic acid solution was added to the coprecipitate, the concentration of the oxalic acid solution was 0.5 mol / L, the reaction temperature was 80° C., the reaction time was 60 min, and after the reaction, a cobalt precipitate and a manganese metal leaching solution were obtained. A sodium hydroxide solution was added to the manganese metal leaching solution to obtain a manganese precipitate.

[0073] After testing the above separated substances, after leaching with a low eutectic solvent, the leaching rate of Li was 90.28%; the leaching rate of Ni was 80.71%, the leaching rate of Co was 20.46%, and the leaching rate of Mn was 14.2%. With the selective recovery of oxalic acid, the selective recovery rates of Li, Mn, Co and Ni were all above 85%. This shows that the hydrogen bond acceptors provided in this scheme can achieve effective recovery of valuable metals in the positive electrode material.

[0074] Example 5

[0075] Corresponding to the above embodiment, this embodiment provides a method for recovering valuable metals in batteries using a deep eutectic solvent, and the specific preparation process is as follows:

[0076] A hydrogen bond acceptor, choline chloride, and a hydrogen bond donor, citric acid, are placed in a beaker, wherein the molar ratio of choline chloride to citric acid is set to 1:2, 35%wt of deionized water is added, the beaker is sealed with plastic wrap, heated to 50°C and stirred for 30 minutes to obtain a transparent and uniform low eutectic solvent;

[0077] The solid-liquid mass ratio of the waste battery positive electrode material to the low eutectic solvent was configured to be 1.5:20, 1.5 g of the waste ternary battery positive electrode material (the positive electrode material is NCM523) was weighed and stirred in a conical flask for leaching, 20 g of the low eutectic solvent was added, the leaching temperature was set to 90 ° C, and the leaching time was 120 min to obtain a leachate and a coprecipitate;

[0078] A saturated oxalic acid solution is respectively prepared as the first acid solution and the oxalic acid solution is prepared as the second acid solution, and the saturated oxalic acid solution is added to the leachate, wherein the molar ratio of the nickel metal in the leachate to the saturated oxalic acid solution is 1:1.1, and after the reaction is completed, a lithium metal leachate and a nickel precipitate are obtained;

[0079] An oxalic acid solution was added to the coprecipitate, the concentration of the oxalic acid solution was 0.5 mol / L, the reaction temperature was 80° C., the reaction time was 60 min, and after the reaction, a cobalt precipitate and a manganese metal leaching solution were obtained. A sodium hydroxide solution was added to the manganese metal leaching solution to obtain a manganese precipitate.

[0080] After testing the above separated substances, at a leaching temperature of 90°C, after DESs leaching, the leaching rate of Li was 99.12%, the leaching rate of Ni was 92.52%, the leaching rate of Co was 27.37%, and the leaching rate of Mn was 29.38%. With the selective recovery of oxalic acid, the selective recovery rates of Li, Mn, Co and Ni were all above 85%.

[0081] Example 6

[0082] Corresponding to the above embodiment, this embodiment provides a method for recovering valuable metals in a battery using a deep eutectic solvent, and the specific preparation process is as follows:

[0083] A hydrogen bond acceptor, choline chloride, and a hydrogen bond donor, citric acid, are placed in a beaker, wherein the molar ratio of choline chloride to citric acid is set to 1:2, 35%wt of deionized water is added, the beaker is sealed with plastic wrap, heated to 50°C and stirred for 30 minutes to obtain a transparent and uniform low eutectic solvent;

[0084] The solid-liquid mass ratio of the waste battery positive electrode material and the low eutectic solvent was configured to be 0.75:20, 0.75 g of the waste ternary battery positive electrode material (the positive electrode material is NCM523) was weighed and stirred in a conical flask for leaching, 20 g of the low eutectic solvent was added, the leaching temperature was set to 80 ° C, and the leaching time was 120 min to obtain a leachate and a coprecipitate;

[0085] A saturated oxalic acid solution is respectively configured as the first acid solution and an oxalic acid solution is configured as the second acid solution, and the saturated oxalic acid solution is added to the leachate, wherein the molar ratio of the nickel metal in the leachate to the saturated oxalic acid solution is 1:1.3, the reaction temperature is 60° C., and the reaction time is continued for 30 minutes after the acid leaching solution is added dropwise, and a lithium metal leachate and a nickel precipitate are obtained after the reaction is completed;

[0086] An oxalic acid solution was added to the coprecipitate, the concentration of the oxalic acid solution was 0.5 mol / L, the reaction temperature was 80° C., the reaction time was 60 min, and after the reaction, a cobalt precipitate and a manganese metal leaching solution were obtained. A sodium hydroxide solution was added to the manganese metal leaching solution to obtain a manganese precipitate.

[0087] After testing the above separated substances, it was found that the leaching rate of Li leached by DESs was 98%, the leaching rate of Ni was 91%, the leaching rate of Co was 27%, and the leaching rate of Mn was 19%. When the molar ratio of oxalic acid solution was 1.3, the selective recovery efficiency of nickel was 94.23%. And it is necessary to control the molar ratio of nickel metal and saturated oxalic acid solution not to exceed 1.6. When the molar amount of oxalic acid exceeds 1.6 times that of nickel element, the nickel recovery rate no longer increases with the amount of oxalic acid; the selective recovery rates of Li, Co and Mn are all above 85%.

[0088] Example 7

[0089] Corresponding to the above embodiment, this embodiment provides a method for recovering valuable metals in batteries using a low eutectic solvent. The difference between this embodiment and Example 6 is that an oxalic acid solution is added to the co-precipitate, wherein the concentration of the oxalic acid solution is 0.8 mol / L.

[0090] After testing the above separated substances, when the concentration of oxalic acid solution increases, the cobalt precipitation rate is 94.4%, and as the oxalic acid concentration gradually increases, the cobalt recovery rate continues to increase. With the synergistic oxalic acid precipitation, the selective recovery rates of Li, Mn and Ni are all above 85%.

[0091] Example 8

[0092] Corresponding to the above embodiment, this embodiment provides a method for recovering valuable metals in batteries using a low eutectic solvent. The difference between this embodiment and Example 6 is that an oxalic acid solution is added to the co-precipitate, wherein the concentration of the oxalic acid solution is configured to be 0.8 mol / L, the reaction temperature is 50°C, and the reaction time is 60 min.

[0093] After testing the separated materials after the above reaction, the leaching rate of Co obtained was not much different from that in Example 6. With the increase of reaction temperature, the precipitation efficiency of cobalt oxalate did not change significantly. With the selective recovery of oxalic acid, the selective recovery rates of Li, Mn and Ni were all above 85%.

[0094] Comparative Example 1

[0095] Corresponding to the above embodiment, the specific preparation process is as follows:

[0096] A hydrogen bond acceptor, choline chloride, and a hydrogen bond donor, citric acid, are placed in a beaker, wherein the molar ratio of choline chloride to citric acid is set to 2:1, 35%wt of deionized water is added, the beaker is sealed with plastic wrap, and stirred at room temperature to obtain a transparent and uniform low eutectic solvent;

[0097] The solid-liquid ratio of the waste battery positive electrode material and the low eutectic solvent was configured to be 1:20 g / ml, 1 g of the waste ternary battery positive electrode material (the positive electrode material is NCM523) was weighed and stirred in a conical flask for leaching, 20 g of the low eutectic solvent was added, the leaching temperature was set to 80 ° C, the leaching time was 90 min, and a leachate and a coprecipitate were obtained;

[0098] After testing the above separated substances, it was found that after leaching with a low eutectic solvent, the leaching rate of Li in the leachate was 80.74%, the leaching rate of Co was 79.11%, the leaching rate of Ni was 79.09%, and the leaching rate of Mn was 95.55%. Since the coprecipitate and the leachate were not further leached with an acid solution and an alkaline solution in this embodiment, Mn, Co and Ni coprecipitated, and the selective extraction of valuable metals could not be achieved.

[0099] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present application.

[0100] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for recovering valuable metals in batteries using a deep eutectic solvent, characterized in that: The method comprises: A deep eutectic solvent is prepared by using a hydrogen bond acceptor, a hydrogen bond donor and a dispersant; Obtaining a waste battery positive electrode material, dispersing the waste battery positive electrode material in the low eutectic solvent, stirring and leaching, and then performing solid-liquid separation to obtain a leachate and a coprecipitate; adding a first acid solution to the leachate to obtain a lithium metal leachate and a nickel precipitate, evaporating and concentrating the lithium metal leachate and adding the resultant to the deep eutectic solvent; A second acid solution is added to the coprecipitate to separate a cobalt precipitate and a manganese metal leaching solution, and an alkali solution is added to the manganese metal leaching solution to obtain a manganese precipitate.

2. The method for recovering valuable metals in batteries using a deep eutectic solvent according to claim 1, characterized in that: The method further comprises: The lithium metal leaching solution is treated by evaporation and concentration or by adding a preset acid solution to obtain a supplementary solvent, and the supplementary solvent is added to the low eutectic solvent for recycling.

3. The method for recovering valuable metals in batteries using a deep eutectic solvent according to claim 1, characterized in that: The molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is (1:0.5) to (1:10).

4. The method for recovering valuable metals in batteries using a deep eutectic solvent according to claim 1 or 2, characterized in that: The hydrogen bond acceptor is one of choline chloride, betaine, and betaine hydrochloride; And / or, the hydrogen bond donor is citric acid.

5. The method for recovering valuable metals in batteries using a deep eutectic solvent according to claim 1 or 2, characterized in that: The dispersant is configured as deionized water, and the method further comprises: After adding the deionized water, heating and stirring are performed at a temperature of 25 to 95° C. and stirring is performed for 15 to 120 minutes to obtain the low eutectic solvent.

6. The method for recovering valuable metals in batteries using a deep eutectic solvent according to claim 1 or 2, characterized in that: The solid-liquid mass ratio of the waste battery positive electrode material to the low eutectic solvent is (0.7:20) to (2.5:20).

7. The method for recovering valuable metals in batteries using a deep eutectic solvent according to claim 1 or 2, characterized in that: The first acid solution is configured as a saturated oxalic acid solution, and the molar ratio of the nickel metal in the leaching solution to the saturated oxalic acid solution is 1:(1.1-1.6).

8. The method for recovering valuable metals in batteries using a deep eutectic solvent according to claim 1 or 2, characterized in that: The second acid solution is configured as an oxalic acid solution, and the concentration of the oxalic acid solution is configured to be 0.15-1.5 mol / L.

9. The method for recovering valuable metals in batteries using a deep eutectic solvent according to claim 1 or 2, characterized in that: The liquid-to-solid ratio of the second acid solution to the coprecipitate is 1:(1-10) mL / g.

10. The method for recovering valuable metals in batteries using a deep eutectic solvent according to claim 1 or 2, characterized in that: The method further comprises: An alkaline solution is added to the manganese metal leaching solution, and the pH of the manganese metal leaching solution is adjusted to 8-12, and the concentration of the alkaline solution is 1.2-3 mol / L.

Images