Extraction agent for separating and recovering lithium and transition metal from waste lithium battery and application thereof

Abstract

The application belongs to the field of waste lithium battery recycling, and particularly relates to an extractant for separating and recycling lithium and transition metals from waste lithium batteries and application thereof, wherein the extractant is selected from phenoxy carboxylic acid compounds, and the phenoxy carboxylic acid compound has a structure shown in formula I: wherein n is independently selected from integers of 1-5; R is independently selected from H, C1-C5 alkyl, and R2 is selected from C1-C5 linear or branched alkyl. 15 When CA-12 is used for recycling lithium and valuable divalent metals (cobalt, nickel and manganese) in waste lithium batteries, CA-12 not only has a better separation effect than traditional extractants P507 and carboxylic acid extractant NDA (neodecanoic acid), but also can reach equilibrium within 5 minutes at room temperature, and can quickly extract lithium and transition metals from waste lithium battery leaching liquor under mild conditions.

Description

Technical Field

[0001] The present invention belongs to the field of waste lithium battery recycling, and in particular relates to an extractant for separating and recycling lithium and transition metals from waste lithium batteries and an application thereof. Background Art

[0002] Lithium's excellent electrochemical properties, such as its high reduction potential, make it an indispensable element in the electric vehicle industry. As a power source for electric vehicles, lithium battery production has increased year by year, but this has also led to the generation of a large number of waste lithium batteries. The positive electrode materials of waste lithium batteries contain heavy metals such as nickel, cobalt, and manganese, and the negative electrode materials contain LiClO4 and LiPF6, which easily dissolve in water and enter the soil, causing serious harm to the environment and organisms. LiClO4 and LiPF6 not only easily seep from waste lithium batteries into the soil, causing environmental pollution, but also LiPF4 generates highly toxic HF upon contact with water, seriously endangering the health of humans and environmental organisms.

[0003] Currently, obtaining lithium from brines and minerals faces a bottleneck, resulting in lithium production capacity failing to meet high market demand. To rationally utilize resources and protect the environment, more attention is currently turning to the recycling of valuable metals in lithium batteries.

[0004] Lithium battery recycling generally involves the following steps: discharge, removal of the organic shell, crushing, screening, leaching, and subsequent metal recovery. Currently, lithium battery metal recycling primarily utilizes three methods: pyrometallurgy, biometallurgy, and hydrometallurgy. While pyrometallurgy can effectively recover cobalt, nickel, and copper from lithium batteries, lithium and manganese recovery remains challenging. Furthermore, the entire pyrometallurgical process requires high temperatures, resulting in high energy consumption and costs. The exhaust gas and residue generated during combustion become secondary pollutants. Hydrometallurgy uses organic solvents to treat non-metallic materials and then gradually separates the metals using a solution method. While energy consumption is lower, it still produces some hazardous gases, such as volatile organic compounds (VOCs), and the organic solvents and solutions used are expensive. Biometallurgy uses substances produced during the growth cycle of specialized microorganisms to dissolve metals from minerals or spent battery powder. This metallurgical method is safer than pyrometallurgy and produces fewer pollutants. However, these microorganisms are mostly acidophilic, and the electrolytes in spent lithium batteries are mostly alkaline, which is unfavorable for microbial growth, resulting in lower efficiency.

[0005] Currently, there are numerous studies on the leaching of lithium batteries using inorganic acids such as hydrochloric acid, sulfuric acid, and orthophosphoric acid. In addition, there are also numerous reports on the leaching of various lithium batteries using organic acids. Compared to inorganic acids, organic acids are more environmentally friendly and biodegradable, producing less waste during the leaching process. However, organic acids are more expensive, which can lead to increased costs.

[0006] Metals in the leachate from lithium batteries can be recovered through extraction and / or precipitation. After obtaining the battery leachate, Chen et al. first used dimethylglyoxime precipitation to remove nickel, then used P204 (dioctyl phosphate) to remove manganese. Lithium and cobalt were precipitated as lithium carbonate and cobalt oxalate, respectively. Wang et al. used P204 to extract manganese and P507 (2-ethylhexyl mono-2-ethylhexyl phosphate) to extract cobalt. The cobalt in the organic phase was recovered by electrodeposition, achieving a cobalt recovery rate of 90% and a purity of 98.8%. Xu et al. used the ionic liquid [P66614]Cl (trihexyltetradecylphosphonium chloride) to recover lithium and cobalt from LCO (lithium cobalt oxide)-type lithium battery leachate.

[0007] However, both P204 and P507 are phosphoric acid extractants, which have the following defects: Although phosphoric acid extractants have good cobalt, nickel and manganese separation capabilities, they are generally incinerated after reaching the end of their service life. During incineration, phosphorus-containing waste is generated. If it enters the circulation, it will cause eutrophication of water bodies and seriously endanger the safety of aquatic organisms. Therefore, carboxylic acid extractants can be a better choice because carboxylic acid extractants only contain C and O, and the products after combustion will not produce substances that are harmful to the environment.

[0008] Carboxylic acids are commonly used extractants in hydrometallurgy. Containing only carbon and oxygen, they adhere to the CHON principle. Extractants that adhere to the CHON principle undergo complete combustion after reaching their useful life, producing no pollutants. Neodecanoic acid and other long-chain carboxylic acids are commonly used to separate metal ions from lithium batteries, but their recovery rate and purity are relatively low. Patent application number 201710648304.2 discloses a method for forming a porous coordination polymer with a metal-organic framework by hydrothermally reacting 1,2,4,5-benzenetetracarboxylic acid as an organic ligand with a positive metal element. However, this method is complex and energy-intensive. Summary of the Invention

[0009] To improve the deficiencies of the prior art, the present invention provides an extractant for separating and recovering lithium and transition metals from waste lithium batteries, as well as a preparation method and application thereof. The extractant includes a phenoxycarboxylic acid compound, which can quickly extract lithium and transition metals from waste lithium battery leachate under mild conditions at a low cost.

[0010] In a first aspect, the present invention provides an extractant for separating and recovering lithium and transition metals from waste lithium batteries. The extractant is selected from a phenoxycarboxylic acid compound having a structure shown in Formula I:

[0011]

[0012] Formula I

[0013] wherein n is selected from an integer of 1-5; R is independently selected from H, C1-C 15 R2 is selected from a straight chain or branched chain alkyl group of C1-C5.

[0014] According to an embodiment of the present invention, the R is independently selected from H, C5-C 12 A straight chain or branched chain alkyl group.

[0015] According to an embodiment of the present invention, the phenoxycarboxylic acid compound has a structure as shown in Formula II:

[0016]

[0017] Formula II

[0018] Wherein, R is selected from C8-C 12 R2 is selected from a straight chain or branched chain alkyl group of C1-C3.

[0019] According to an embodiment of the present invention, the phenoxycarboxylic acid compound is selected from at least one of 4-tert-octylphenoxyacetic acid (POAA), 4-tert-octylphenoxyisopropionic acid (POPA), 4-tert-octylphenoxybutyric acid (POPA), and 2-sec-octylphenoxyacetic acid (CA-12), for example, CA-12.

[0020] In a second aspect, the present invention provides an extraction composition for separating and recovering lithium and transition metals in waste lithium batteries. The extraction composition comprises an extractant and a phase modifier.

[0021] According to an embodiment of the present invention, the extractant has the definition as described above.

[0022] According to an embodiment of the present invention, the concentration of the extractant in the extraction composition is 0.06 mol / L~0.2 mol / L, preferably the concentration of the extractant is 0.09 mol / L~0.15 mol / L, for example, 0.08 mol / L, 0.09 mol / L, 0.10 mol / L, 0.11 mol / L, 0.12 mol / L, 0.14 mol / L, 0.16 mol / L, 0.18 mol / L, 0.20 mol / L.

[0023] According to an embodiment of the present invention, the phase modifier accounts for 0-20% by volume of the extraction composition, preferably 3-18% by volume of the extraction composition, for example, 2%, 4%, 6%, 8%, 10%, 12%, or 16%.

[0024] According to an embodiment of the present invention, the phase modifier is selected from a straight-chain or branched alcohol with a C6 or higher content, and preferably the phase modifier is selected from one or more of n-hexanol, n-heptanol, n-octanol, isooctyl alcohol, n-nonanol, decanol, undecanol, and dodecanol, for example, n-octanol and / or isooctyl alcohol.

[0025] According to an embodiment of the present invention, the extraction composition further comprises a diluent, which is selected from commonly used organic solvents, preferably kerosene, sulfonated kerosene, liquid alkanes, liquid aromatic compounds, liquid halogenated hydrocarbons or a mixture of several thereof, such as sulfonated kerosene.

[0026] According to an embodiment of the present invention, the liquid alkane is selected from alkanes of C5 or above, and preferably the liquid alkane is selected from alkanes of C6 or above, for example, one or more of hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, and hexadecane.

[0027] According to an embodiment of the present invention, the liquid aromatic hydrocarbon is selected from one or more of benzene, toluene, xylene, ethylbenzene, xylene, and cumene.

[0028] According to an embodiment of the present invention, the liquid halogenated hydrocarbon is selected from polyhalogenated hydrocarbons, and preferably the liquid halogenated hydrocarbon is selected from one or more of chloroform, dichloromethane, carbon tetrachloride, ethane halides, tetrahalopropanes, pentahalobutanes, dihalogenated vinyls, trihalogenated propenes, and tetrahalobutenes.

[0029] In a third aspect, the present invention provides a method for separating and recovering lithium and transition metals from waste lithium batteries using the above-mentioned extractant or extraction composition, comprising the following steps:

[0030] a. preparing an extractant into an organic phase and saponifying the extractant to obtain a saponified organic phase;

[0031] b. Mixing the saponified organic phase with the waste lithium battery leachate and extracting.

[0032] According to an embodiment of the present invention, the extractant has the definition as described above.

[0033] According to an embodiment of the present invention, the following steps are also included before the step: crushing the waste lithium batteries to obtain battery powder, reacting and leaching the battery powder in an acid solution to obtain a waste lithium battery leachate, and adjusting the pH of the waste lithium battery leachate to 2~4.

[0034] According to an embodiment of the present invention, the pH of the waste lithium battery leachate is adjusted to 3.

[0035] According to an embodiment of the present invention, the solid-liquid ratio (mass-to-volume ratio) S / L of the waste lithium battery powder and the acid solution is 1-100, preferably the solid-liquid ratio S / L of the waste lithium battery powder and the acid solution is 10-50, and further preferably, the solid-liquid ratio S / L of the waste lithium battery powder and the acid solution is 15-30, for example, 15, 18, 20, 25, 30, 35, or 40.

[0036] According to an embodiment of the present invention, the acid solution is selected from one or more of hydrochloric acid, sulfuric acid, and nitric acid, for example, hydrochloric acid.

[0037] According to an embodiment of the present invention, the concentration of the acid solution is 0.1 mol / L to 12 mol / L, preferably the concentration of the acid solution is 1 mol / L to 5 mol / L, for example, 3 mol / L hydrochloric acid.

[0038] According to an embodiment of the present invention, the battery powder leaching temperature is 30°C~100°C, and the leaching time is 0~120min. Preferably, the battery powder leaching temperature is 50°C~80°C, and the leaching time is 15~60min. For example, the battery powder leaching temperature is 70°C, and the leaching time is 50min.

[0039] According to an embodiment of the present invention, the reaction of the battery powder in the acid solution is carried out under stirring conditions, and the stirring speed is 100 rpm to 600 rpm, for example, 400 rpm.

[0040] As an example, waste lithium batteries are crushed to obtain battery powder, and the battery powder is reacted and leached in an acid solution to obtain a waste lithium battery leachate, including the following steps: in a 250 mL two-necked round-bottom flask equipped with a reflux condenser, 3 g of battery powder and 150 mL of 3 mol / L hydrochloric acid are added at a stirring speed of 400 rpm, the mixture is reacted at a temperature of 70°C for 50 minutes, and the leachate is filtered.

[0041] According to an embodiment of the present invention, after obtaining the leachate, the following steps are further included: removing Cu in the leachate 2+ 、Fe 3+ and Al 3+ .

[0042] According to an embodiment of the present invention, the Cu 2+ The method comprises the following steps: mixing the leaching liquid with the extractant N902, and separating to obtain an aqueous phase.

[0043] According to an embodiment of the present invention, Fe in the leachate is removed 3+ and Al 3+The method comprises the following steps: hydrolyzing the aqueous phase obtained by separating the aqueous phase after mixing with N902, preferably the hydrolysis comprises adding an alkaline solution to the aqueous phase to adjust the pH to greater than 4, then allowing the aqueous phase to stand, and then filtering the generated precipitate with filter paper to determine whether the Fe is completely removed. 3+ and Al 3+ .

[0044] According to an embodiment of the present invention, the alkaline solution is selected from at least one of a sodium hydroxide solution, a sodium bicarbonate solution or a sodium carbonate solution.

[0045] According to an embodiment of the present invention, the concentration of the alkaline solution is 4-6 mol / L, for example, 5 mol / L of sodium hydroxide.

[0046] According to an embodiment of the present invention, the hydrolysis package adjusts the pH to greater than 5, for example, 5 or 6.

[0047] According to an embodiment of the present invention, the step of preparing the extractant into an organic phase in step a comprises the following steps: mixing the extractant, the modifier and the diluent to obtain an organic phase.

[0048] The extractant, modifier and diluent have the same definitions as above.

[0049] According to an embodiment of the present invention, the saponification degree of the saponified organic phase in step a is 35% to 45%, for example, 40%.

[0050] According to an embodiment of the present invention, saponifying the organic phase comprises the following steps: adding alkali solution to the organic phase until the saponification degree is 35% to 45%.

[0051] According to an embodiment of the present invention, the alkali solution is a strong alkali solution, preferably a high-concentration strong alkali solution, such as sodium hydroxide solution, potassium hydroxide solution, ammonia water, ammonium bicarbonate or sodium bicarbonate solution.

[0052] According to an embodiment of the present invention, the concentration of the alkali solution is 5-12 mol / L, for example, 5 mol / L.

[0053] According to an embodiment of the present invention, the volume ratio of the organic phase to the waste lithium battery leachate is (1:0.5~1:4), for example, 1:1.

[0054] According to the embodiment of the present invention, in the mixed solution of the waste lithium battery leaching solution and the saponified organic phase in step b, Li + 、Ni 2+ 、Co 2+ 、Mn 2+ The concentration is 0.001~0.01 mol / L, for example 0.005 mol / L.

[0055] According to an embodiment of the present invention, in the mixed solution of the saponified organic phase and the waste lithium battery leachate in step b, the concentration of the extractant is 0.05~0.20mol / L, preferably the concentration of the extractant is 0.08~0.15mol / L, for example 0.11mol / L.

[0056] According to an embodiment of the present invention, the extraction in step b is carried out at a temperature of 20-30°C, preferably at a temperature of 23-26°C, for example, 25°C.

[0057] According to an embodiment of the present invention, the extraction time in step b is 1 to 20 min, preferably the extraction time is 1 to 10 min, for example, 4 min, 5 min, or 6 min.

[0058] As an example, step b includes the following steps: mixing the saponified organic phase with the battery feed solution, and shaking at room temperature for 5 minutes to reach equilibrium.

[0059] According to an embodiment of the present invention, step b is followed by the following step: centrifuging the extracted mixed solution to separate the aqueous phase and the loaded organic phase.

[0060] According to an embodiment of the present invention, step b is followed by the following step: mixing the aqueous phase as a battery feed solution with the organic phase and / or the saponified organic phase again for secondary extraction.

[0061] According to an embodiment of the present invention, step b is followed by the following step: mixing the loaded organic phase with a stripping agent to obtain an organic phase to be used and a mixed ion solution.

[0062] According to an embodiment of the present invention, the organic phase to be used is the organic phase and / or saponified organic phase as described above.

[0063] According to an embodiment of the present invention, the stripping agent is an acid and / or a soluble salt solution, and one or more of hydrochloric acid, sulfuric acid, and acetic acid can be selected.

[0064] As an example, step b further includes the following steps: eluting the loaded organic phase with hydrochloric acid to obtain a mixed ionic liquid, and precipitating the mixed ionic liquid to obtain Ni 2+ 、Co 2+ 、Mn 2+ The corresponding salt is precipitated, for example, using oxalic acid.

[0065] According to an embodiment of the present invention, the concentration of the acid solution is 0.1-0.6 mol / L, for example, 0.4 mol / L HCl.

[0066] According to an embodiment of the present invention, step b further includes the following steps: precipitating Li from the separated aqueous phase + The corresponding salts are precipitated, for example, using carbonates.

[0067] According to an embodiment of the present invention, the following step is further included after step b: recovering the unused organic phase, and reusing the unused organic phase as an organic phase and / or a saponified organic phase.

[0068] Beneficial effects

[0069] (1) The inventor unexpectedly discovered that when phenoxycarboxylic acid CA-12 (sec-octylphenoxy substituted acetic acid) is used as an extractant to recover divalent metals from waste lithium batteries, the battery powder leachate can be directly extracted to recover divalent metal ions. This not only makes the steps simpler but also has better results.

[0070] (2) The present invention uses CA-12 to recover lithium and valuable divalent metals (cobalt, nickel, and manganese) from waste lithium batteries. CA-12 not only has a better separation effect than traditional extractants P507 and carboxylic acid extractants NDA (neodecanoic acid), but also can reach equilibrium within 5 minutes at room temperature, that is, it can quickly extract lithium and transition metals from waste lithium battery leachate under mild conditions; in the actual battery powder metal recovery experiment, after two-stage extraction, 99.7% of Ni 2+ , 99.4% Co 2+ , 98.45% Mn 2+ was extracted into the organic phase, with only 6.81% Li + The divalent metal ions in the organic phase are converted into oxalate precipitates, while the Li + It is converted into lithium carbonate precipitate. After XRD identification, the purity of lithium carbonate precipitate reaches 97.7%.

[0071] (3) After extraction, CA-12 in the present invention can be regenerated by elution, and when used for extraction again, the extraction effect is still good. CA-12 has a good effect on Co 2+ 、Ni 2+ 、Mn 2+ The extraction rate of Li + The extraction rate is only slightly increased and it can be reused many times, which can effectively reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 Schematic diagram of the structures of different extractants used in the embodiments of the present invention;

[0073] Figure 2(a) is a diagram showing the raffinate phenomenon after adding TBP and isooctyl alcohol in Example 3 of the present invention, and 2 (b) is a diagram showing the effect of the amount of isooctyl alcohol added on the extraction;

[0074] Figure 3 Graph showing the effect of pH on the extraction rate of various metal ions in Example 4 of the present invention;

[0075] Figure 4 (a) is a diagram showing the effect of equilibrium time on extraction in Example 5 of the present invention; Figure 4 (b) is the effect of extraction temperature on extraction;

[0076] Figure 5 (a) is a graph showing the effect of CA-12 concentration on extraction in Example 6 of the present invention; Figure 5 (b) is the effect of saponification degree on extraction; Figure 6 (a) is Li under different conditions in Example 7 of the present invention + 、Ni 2+ 、Co 2+ 、Mn 2+ Extraction rate curve; Figure 6 (b) is a graph showing separation coefficients under different conditions;

[0077] Figure 7 is the XRD pattern of LiCO3 precipitate in Example 7 of the present invention;

[0078] Figure 8 The metal extraction effects of different extractants on the simulated leachate in the comparative examples of the present invention are shown in FIG.

[0079] Figure 9 (a), (b), and (c) are the extraction of Co by CA-12 in the comparative example of the present invention. 2+ 、Ni 2+ 、Mn 2+ Slope analysis diagram of ; Figure 9 (d) is the FT-IR spectra of the extractant, the extractant after saponification, and the extractant;

[0080] Figure 10 Graph showing the effect of HCl concentration on stripping efficiency in Example 8 of the present invention;

[0081] Figure 11 This is a test chart of the cycle performance of CA-12 in Example 9 of the present invention. DETAILED DESCRIPTION

[0082] The following will further describe the extractant of the present invention, its preparation method, and its application in detail with reference to specific examples. It should be understood that the following examples are merely illustrative and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection intended by the present invention.

[0083] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0084] Specifically, the sources of the materials and reagents used in the following examples are as follows:

[0085] Anhydrous lithium chloride and neodecanoic acid (NDA) were purchased from the Adamas reagent platform, nickel chloride hexahydrate, cobalt chloride hexahydrate, manganese chloride tetrahydrate, sodium hydroxide, hydrochloric acid, and sodium carbonate were purchased from Sinopharm Chemical Reagent Co., Ltd., and isooctyl alcohol was purchased from Tokyo Chemical Reagent Co., Ltd. All reagents were of analytical grade. Extractants P204 and P507 were purchased from Luoyang Aoda Chemical Reagent Co., Ltd., CA-12 extractant (purity 90%-92%) was purchased from Shanghai Lai Ya Shi Reagent Co., Ltd., and extractant N902 (purity 96%) was purchased from Zhengzhou Synthetic New Materials Technology Co., Ltd. Extractants P204, P507, CA-12, and N902 can all be used directly without purification. The diluent was sulfonated kerosene 260, and deionized water was prepared using the Smart-S30UV ultrapure water system of Shanghai Hetai Company. The deionized conductivity was 18.2 MΩ. The pH meter was pHS-3C produced by Shanghai Leici Instrument Co., Ltd. The extractant structures used in the following examples are as follows: Figure 1 The test methods and instruments involved in the following examples are as follows:

[0086] Extraction method: Equal volumes of organic and aqueous phases were shaken at room temperature for 5 minutes to reach equilibrium. The aqueous and organic phases were centrifuged at 5000 rpm for 1 minute to separate the aqueous phase. Unless otherwise specified, the extraction time was 5 minutes, the extraction temperature was room temperature, and the phase ratio was 1.

[0087] In the following examples, ICP-OES (inductively coupled plasma optical emission spectrometer, model: Horiba JobinYvon Ultima 2) was used to determine the ion concentration in the aqueous phase, and FT-IR (Fourier transform infrared spectroscopy, model: ThermoFisher Nicolet iS 50) was used to determine the peak changes of functional groups before and after extraction (500 cm -1 ~4000cm -1), XRD (X-ray diffractometer, model MiniFlex 600 X-ray, BRUKER Company, Germany) was used to analyze the crystal changes of Li salt before and after battery leaching.

[0088] The extraction rate (E), distribution coefficient (D), separation coefficient (β), and stripping rate (S) are defined as follows:

[0089]

[0090]

[0091]

[0092]

[0093] in, is the metal ion concentration in the aqueous phase of the starting liquid, The concentration of metal ions in the aqueous phase after the extraction reaches equilibrium. is the metal ion concentration in the stripping aqueous phase.

[0094] Reference example: Leaching of waste battery powder

[0095] Leaching experiment reference (T. Liu, J. Chen, X. Shen, H. Li, Regulating and regenerating the valuable metals from the cathode materials in lithium-ion batteries by nickel-cobalt-manganese co-extraction, Sep Purif Technol, 259(2021) 118088), first, 0.5g lithium battery powder was completely leached with 40mL of aqua regia (concentrated hydrochloric acid:concentrated nitric acid volume ratio = 3:1), and the concentration of each metal ion contained in the leachate was determined.

[0096] The battery powder used in the aqua regia leaching experiment in this reference example is to determine the content of metal ions contained in the battery powder, which is used as a benchmark. The leaching rates of various metals thereafter are all based on this benchmark. If the battery powder used in the experiment is a multiple of the mass of the battery powder used in the aqua regia leaching, then the concentration of the metal ions leached out of the aqua regia is multiplied by the corresponding multiple to obtain the content of the metal ions contained. Table 1 is the result of the battery leaching, and the mass fraction of the total content of the corresponding ions to the mass of the leached battery powder is used in the table.

[0097] Table 1 shows the contents of various metal ions and graphite in the waste lithium battery powder used in this reference example (and the following examples).

[0098] Table 1. Composition of metal ions in waste lithium battery powder

[0099]

[0100] Example 1: Leaching of waste battery powder

[0101] In a 250 mL two-necked round-bottom flask equipped with a reflux condenser (to reduce the volatilization of acid at high temperature), 3 g of battery powder and 150 mL of 3 mol / L hydrochloric acid were added at a stirring speed of 400 rpm. The mixture was reacted at a temperature of 70 ° C and a stirring speed of 400 rpm for 50 minutes, and the leachate was filtered.

[0102] Table 2 shows the composition of the leachate obtained by leaching battery powder with hydrochloric acid in this embodiment. Taking the components in Table 1 as a reference, the hydrochloric acid in this embodiment is used to leach the Li + 、Ni 2+ 、Co 2+ 、Mn 2+ The leaching rates are all greater than 95%.

[0103] Table 2. Composition of leachate

[0104]

[0105] Example 2: Method for extracting and separating the leachate in Example 1

[0106] S1, 150mL of the leachate in Example 1 was adjusted to pH 2 using sodium hydroxide solution, N902 was first dissolved in kerosene to prepare an organic phase with a concentration of 0.06mol / L and added to the leachate to separate the impurity Cu 2+ , then add 0.45mL of 5mol / L sodium hydroxide solution to adjust the pH to 5, and Fe 3+ and Al 3+ Hydrolysis is converted into Al(OH)3 and Fe(OH)3 is removed, thereby obtaining a molten salt containing only Li + and Ni 2+ 、Co 2+ 、Mn 2+ The battery solution was then adjusted to pH 3 using 3 mol / L hydrochloric acid.

[0107] S2, 0.11mL CA-12 extractant was mixed with 0.5mL (10% of the volume of the organic phase) phase modifier isooctyl alcohol and 3mL sulfonated kerosene to obtain 5mL of organic phase, 5mol / L sodium hydroxide solution was added to the organic phase until the saponification degree was 40%, sulfonated kerosene was added to the saponification system to a total volume of 5mL to obtain an extracted organic phase, 5mL of the battery solution with a pH of 3 in step S1 was added to the 5mL extracted organic phase to obtain a mixed solution, in which the concentration of CA-12 in the mixed solution was 0.11mol / L, Ni 2+ 、Co 2+ 、Mn 2+ The concentration was 0.005 mol / L and the extraction was carried out at 25°C for 5 min.

[0108] Among them, the saponification specifically adopts the following steps: first, according to the required extractant concentration, the molar amount of the extractant is calculated according to the stoichiometric equation: n (extractant molar amount) = c (extractant concentration) * V (organic phase volume), and then multiplied by the molecular weight of CA-12 extractant (264.35, purity is 90-92%, impurities do not affect extraction and can be ignored) to obtain the mass of CA-12 to be added, which is added to a special test tube used for extraction, and then a phase modifier is added at 10% of the volume of the organic phase (the organic phase volume is set to 5 mL in the experiment. In actual practice, the volume of the organic phase can be set according to actual needs). According to the required saponification degree, the corresponding volume of 5 mol / L sodium hydroxide solution is added, and then the solvent sulfonated kerosene is added to the set organic phase volume. The test tube stopper is tightened, placed in an oscillator for 15 minutes, and centrifuged in a centrifuge at 3000 rpm for 30 seconds to obtain the saponified organic phase. Then, an equal volume of leachate is added for subsequent experiments.

[0109] Example 3: Effect of Phase Modifiers

[0110] Phase modifiers can improve extraction phenomena, as verified by the following experiments:

[0111] Experiment 1: When preparing the organic phase for extraction, if no phase modifier is added and the extractant CA-12 is directly saponified, the resulting organic phase will be turbid and cannot be used further.

[0112] Experiment 2: In this experiment, except that the phase modifier was replaced by TBP (tributyl phosphate), the rest of the steps were the same as S2. Figure 2 (a) It can be seen that after adding TBP, the extract becomes turbid and cannot be used further; however, after adding isooctyl alcohol as a phase modifier, the raffinate remains transparent. Therefore, isooctyl alcohol is the most preferred phase modifier. The addition amount of isooctyl alcohol or TBP is 5% of the organic phase.

[0113] Experiment 3: In this experiment, except for using different doses of isooctyl alcohol as a phase modifier, the remaining steps are the same as S1-S3 in Example 2. The extraction rate of cobalt, nickel and manganese ions is determined. Figure 2 (b) It can be seen that when different amounts of isooctanol in the organic phase (5%, 10%, 15%, and 20% of the battery liquid volume) are used for extraction, there is no significant difference in the extraction rate of cobalt, nickel, and manganese ions.

[0114] Example 4: Effect of pH of the starting solution on extraction

[0115] In this example, except for the different pH values ​​(1, 2, 4, 5) of the liquid prepared in step S1, the other steps are the same as those in Example 2. + 、Co 2+ 、Mn 2+ extraction rate.

[0116] See also Figure 3 It can be seen that at pH 1, Ni 2+ 、Co 2+ 、Mn 2+ The extraction rate is less than 6%. At pH 2, Ni 2+ 、Co 2+ 、Mn 2+ The extraction rates of Ni were 51%, 42% and 30% respectively. The low extraction rate was due to proton competition extraction. The high acidity resulted in an increase in the proportion of CA12-bound protons. When the pH was 3, Ni 2+ 、Co 2+ 、Mn 2+ The extraction rates of Ni were 74%, 66%, and 52% respectively. When the pH value continued to increase to 4 and 5, Ni 2+ 、Co 2+ 、Mn 2+ The extraction rate of Li + The extraction rate will increase, so in order to reduce Li + The optimal pH is 3.

[0117] From the above analysis, it can be seen that the pH of the battery liquid has a great influence on the extraction. High pH will increase the risk of metal ion hydrolysis, while low pH will inhibit the extraction. Therefore, it is necessary to select a suitable pH to obtain a better extraction effect.

[0118] Example 5: Effect of temperature and time on extraction.

[0119] In this embodiment, except for the different extraction temperatures (30°C, 35°C, 40°C, 45°C, and 50°C) in step S2, the other steps are the same as those in Example 2. 2+ 、Co 2+ 、Mn2+ The extraction rate and the extraction equilibrium time at a temperature of 25°C were measured.

[0120] If an extractant can quickly reach extraction equilibrium, it means that it has excellent extraction kinetics, which is also a necessary requirement for its industrial application.

[0121] See also Figure 4 (a) It can be seen that the extraction energy at a temperature of 25°C reaches equilibrium within 5 minutes, indicating that the extraction of battery liquid using CA-12 as an extractant has excellent extraction kinetics. Continuing to increase the oscillation time, the extraction rate of each divalent metal does not increase significantly. During the extraction process, there will be enthalpy changes, which are usually accompanied by thermal effects. Therefore, changing the extraction temperature may improve the extraction effect.

[0122] See also Figure 4 (b) It can be seen that the extraction rate did not increase significantly when the temperature gradually increased from 30℃ to 50℃, indicating that increasing the temperature had no promoting effect on the extraction. Therefore, the optimal extraction conditions were 5 minutes of oscillation time and extraction at room temperature.

[0123] Example 6: Effect of extractant concentration on extraction.

[0124] In order to recycle Co as much as possible 2+ 、Ni 2+ 、Mn 2+ , making it better with Li + For separation, an appropriate concentration of extractant is required.

[0125] In this embodiment, except for the different concentrations of the extractant in step S2 (set to 0.07 mol / L, 0.06 mol / L, 0.10 mol / L, 0.11 mol / L, and 0.12 mol / L in sequence), the other steps are the same as those in Example 1. The Li + 、Ni 2 + 、Co 2+ 、Mn 2+ extraction rate.

[0126] See also Figure 5 As shown in (a), when the concentration of CA12 increases from 0.07 mol / L to 0.12 mol / L, Co 2+ 、Ni 2 + 、Mn 2+ The extraction rate of CA12 is positively correlated with that of Li. + The loss of Co increases rapidly. When the CA-12 concentration is 0.11 mol / L, 2+ 、Ni2+ 、Mn 2+ The extraction rate of Li + The extraction rate is 7%, because at this concentration, Li + The loss is small, and continuing to increase the concentration of CA-12 will lead to Li + Therefore, 0.11 mol / L was selected as the optimal CA-12 extractant concentration to avoid large losses.

[0127] Example 7: Effect of saponification concentration on extraction.

[0128] The saponification degree can change the extraction and separation effect of metal ions. In this embodiment, except for the saponification degree in step S2 (set to 30%, 35%, 40%, 45%, and 50% in sequence), the other steps are the same as those in Example 2. The Li + 、Ni 2+ 、Co 2+ 、Mn 2+ extraction rate.

[0129] See also Figure 5 As shown in (b), when the saponification degree is 30% and 35%, the divalent metal ion Co 2+ 、Ni 2+ 、Mn 2+ The extraction rate is low, and a large amount of divalent metal ions remain in the aqueous phase; when the saponification degree increases to 40%, 99% of the divalent metals are co-extracted, and at this time Li + The loss is 7%; when the saponification degree continues to increase to 45% and 50%, the divalent metal ions are completely extracted, and the saponified part of the extractant still remains, so Li + was extracted in large quantities, resulting in a decrease in the selectivity of the extraction system. Considering that Co 2+ 、Ni 2 + 、Mn 2+ He Li + In order to improve the extraction and separation effect, a saponification degree of 40% was selected as the optimal saponification degree.

[0130] Example 8: Effect of phase ratio on extraction.

[0131] In this embodiment, except for the difference in the ratio in step S3 (set to 1:1, 1.5:1, 2:1, 2.5:1, and 3:1 in sequence), the other steps are the same as those in Example 2. When the ratio is 1.5 and 2, an extraction is performed after step S3 to determine the Li + 、Ni 2+ 、Co 2+ 、Mn 2+ extraction rate.

[0132] See also Figure 6 (a) It can be seen that Li + 、Ni 2+ 、Co 2+ 、Mn 2+ The extraction rate of Co 2+ 、Ni 2+ 、Mn 2+ The extraction rate of Li + The loss rate reached 12%; see Figure 6 (b) It can be seen that the separation coefficient is positively correlated with the ratio of O:A, although βCo 2+ / Li + , βNi 2+ / Li + ,βMn 2+ / Li + It is relatively large when O:A is 2.5:1 and 3:1, but Li + More co-extracted; when the ratio is 2, the first stage extraction cannot completely extract the ions, but after two-stage extraction (the ratio is O:A=2:1 in both extractions), the organic phase becomes turbid, so the ratio of 2 is not conducive to the separation and recovery of metals; when the ratio is 1.5, after two-stage extraction (the ratio of both extractions is O:A=1.5:1), Ni 2+ 、Co 2+ 、Mn 2+ The extraction rates were 99.7%, 99.4% and 98.45%, respectively. The raffinate and organic phase remained clear and transparent. The components of the raffinate are shown in Table 3. The ions loaded in the organic phase were eluted with 0.4 mol / L HCl to obtain a mixed ion solution, while Li + Only 6.81% is lost. The raffinate is heated to 90-100°C and saturated sodium carbonate solution is added to obtain LiCO3 precipitate. The purity of the LiCO3 precipitate is determined by referring to Figure 7 As shown, Li + The purity is 97.7%.

[0133] Therefore, a ratio of 1.5 can effectively extract Ni 2+ 、Co 2+ 、Mn 2+ He Li + , and can effectively + with Ni 2+ 、Co 2+ 、Mn 2+ Separation, avoid Li + loss.

[0134] Table 3. Composition of raffinate and leachate

[0135]

[0136] Comparative Example: Extraction Agent Comparison Experiment

[0137] P204 and P507 are commonly used organophosphoric acid extractants for the recovery of valuable metals from spent lithium batteries. Versatic 10 acid has recently been reported as an extractant for the co-extraction of lithium batteries.

[0138] In this comparative example, except that CA12 was replaced by P204, P507, and Versatic 10 acid (NDA) in sequence, the remaining steps were the same as those in Example 1. The Li + 、Ni 2+ 、Co 2+ 、Mn 2+ extraction rate.

[0139] See also Figure 8 As shown, CA-12 has a higher effect on Ni than NDA and P507. 2+ 、Co 2+ 、Mn 2+ It has stronger extraction ability. In addition, CA-12 has a stronger effect on Li + and Ni 2+ 、Co 2+ 、Mn 2+ The selectivity is better than P204.

[0140] Extraction mechanism

[0141] To analyze the CA-12 extracted Co 2+ 、Ni 2+ 、Mn 2+ The extraction process was studied by FT-IR and slope analysis. Figure 9 FT-IR spectrum shown in (a), 1735 cm -1 The absorption peak is the carbonyl absorption peak of carboxylic acid. 2 + 、Ni 2+ 、Mn 2+ After that, the vibration peak shifted to 1604cm -1 , indicating that the extraction process is an ion exchange process in which carboxylic acid groups participate; see Figure 9 (b) The slope analysis diagram shows that Ni 2+ 、Co 2+ 、Mn 2+ The slopes were 1.76, 1.77, and 1.72, respectively, and the ratio of the extracted metal ions to CA-12 concentration was close to 1:2.

[0142] The stoichiometric formula for metal ion extraction by CA-12 is shown in formulas (5) and (6).

[0143] (5)

[0144] (6)

[0145] Among them, HA is CA-12, M 2+ For You 2+ 、Co 2+ 、Mn 2+

[0146] Example 8: Elution performance of the extractant

[0147] The acid concentration used during elution is also a reference for whether an extractant has potential application prospects. In this example, except that the HCl concentration (0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L) is different from that in Example 2, the other steps are the same as those in Example 2. The Ni content after extraction with different HCl concentrations is determined. 2+ 、Co 2+ 、Mn 2+ extraction rate.

[0148] See also Figure 10 As shown, the metal ion Ni 2+ 、Co 2+ 、Mn 2+ The elution rate of Co increases gradually with the increase of HCl concentration from 0.01mol / L to 0.05mol / L. When the HCl concentration is 0.04mol / L, the elution rate of Co increases gradually with the increase of HCl concentration from 0.01mol / L to 0.05mol / L. 2+ 、Ni 2+ 、Mn 2+ It can be eluted with equivalent weight, indicating that CA-12 has excellent stripping performance.

[0149] Example 9: Cycling Performance of CA-12

[0150] The extractant can still maintain a good extraction effect after multiple cycles, which is a reference for whether the extractant is excellent. In this example, 0.4 mol / L HCl was used to strip and separate the liquid after step S3 of Example 2. The loaded metal ions were completely stripped into the HCl. The separated organic phase was washed with deionized water until neutral and then used as the organic phase for the next extraction according to step S3 of Example 2. The extraction was repeated 5 times.

[0151] See also Figure 11 As shown, the extractant has a great influence on Co 2+ 、Ni2+ 、Mn 2+ The extraction rate of Li + The extraction rate increased only slightly, indicating that CA-12 has good recycling performance.

[0152] In the present invention, when CA-12 is used to recover lithium and valuable divalent metals (cobalt, nickel, and manganese) from waste lithium batteries, CA-12 is superior to traditional extractants P507 and carboxylic acid extractant NDA (neodecanoic acid), and can reach equilibrium within 5 minutes at room temperature. During the extraction process, cobalt, nickel, and manganese are co-extracted into the organic phase, and 0.04 mol / L HCl can elute the loaded metal ions equivalently.

[0153] In the actual battery powder metal recovery experiment, after two-stage extraction, 99.7% of Ni 2+ , 99.4% Co 2+ , 98.45% Mn 2+ was extracted into the organic phase, with only 6.81% Li + The loss of divalent metal ions in the organic phase was converted into oxalate precipitates, and the Li+ in the extract was converted into lithium carbonate precipitates. After XRD identification, the purity of the lithium carbonate precipitate reached 97.7%. From the above experimental results, it can be seen that sec-octylphenoxyacetic acid (CA-12) has potential application prospects in the field of valuable metal recovery from waste lithium batteries.

[0154] The above examples illustrate the specific embodiments of the present invention. However, the scope of protection of the present invention is not limited to the above-mentioned exemplary embodiments. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art within the spirit and principles of the present invention shall be included in the scope of protection of the claims of the present invention.

Claims

1. A method for separating and recovering lithium and transition metals from waste lithium batteries, characterized in that: The method comprises the following steps: a. 2-sec-octylphenoxyacetic acid (CA-12), a phase modifier, and a diluent are prepared into an organic phase and saponified to obtain a saponified organic phase. The saponification degree of the saponified organic phase is 40%. The phase modifier is n-octanol and / or isooctyl alcohol, and the phase modifier accounts for 4-20% of the volume of the organic phase. b. Crush the waste lithium batteries to obtain battery powder, and leach the battery powder in acid to obtain waste lithium battery leachate, and remove Cu 2+ 、Fe 3+ and Al 3+ , adjust the pH of the waste lithium battery leachate to 3; c. Mix the saponified organic phase with the waste lithium battery leachate and extract at 25°C for 5 minutes, wherein the concentration of 2-sec-octylphenoxyacetic acid (CA-12) in the mixture of the saponified organic phase and the waste lithium battery leachate is 0.11 mol / L.

2. The method for separating and recovering lithium and transition metals from waste lithium batteries according to claim 1, wherein: The solid-to-liquid ratio S / L of the battery powder to the acid solution is 1-100, with the unit being g / mL.

3. The method according to claim 2, characterized in that The solid-to-liquid ratio S / L of the battery powder to the acid solution is 10-50, and the unit is g / mL.

4. The method for separating and recovering lithium and transition metals from waste lithium batteries according to claim 1, wherein: The concentration of the acid solution is 0.1 mol / L to 12 mol / L.

5. The method for separating and recovering lithium and transition metals from waste lithium batteries according to claim 1, characterized in that: The battery powder leaching temperature is 30° C. to 100° C., and the leaching time is 15 to 120 minutes.

6. The method for separating and recovering lithium and transition metals from waste lithium batteries according to any one of claims 1 to 5, characterized in that: The volume ratio of the organic phase to the waste lithium battery leachate is 1:0.5 to 1:

4.

7. The method for separating and recovering lithium and transition metals from waste lithium batteries according to any one of claims 1 to 5, characterized in that: After step c, the method further includes the following steps: centrifuging the extracted mixed solution to separate an aqueous phase and a loaded organic phase; mixing the aqueous phase as a waste lithium battery leachate with the organic phase and / or the saponified organic phase again to perform a secondary extraction; The loaded organic phase is mixed with a stripping agent to obtain an organic phase to be used and a mixed ion solution, wherein the stripping agent is an acid and / or a soluble salt solution.

8. The method for separating and recovering lithium and transition metals from waste lithium batteries according to claim 7, wherein: After step c, the following steps are also included: eluting the loaded organic phase with hydrochloric acid to obtain a mixed ion solution, and precipitating the mixed ion solution to obtain Ni 2+ 、Co 2+ 、Mn 2+ For the corresponding salt, the concentration of the hydrochloric acid solution is 0.1-0.6 mol / L.

9. The method for separating and recovering lithium and transition metals from waste lithium batteries according to claim 7, characterized in that: Step c also includes the following steps: precipitating Li from the separated aqueous phase + recovering the standby organic phase, and reusing the standby organic phase as an organic phase and / or a saponified organic phase.

10. The method for separating and recovering lithium and transition metals from waste lithium batteries according to claim 9, characterized in that: Li was precipitated from the separated aqueous phase. + The corresponding salts were precipitated using carbonates.

11. The method for separating and recovering lithium and transition metals from waste lithium batteries according to any one of claims 1 to 5, characterized in that The diluent is one or a mixture of kerosene, liquid alkane, liquid aromatic compound and liquid halogenated hydrocarbon.

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