Method for recovering positive electrode active material precursor

Abstract

The present invention provides a method for recovering a positive electrode active material precursor according to an embodiment of the present invention, which comprises: preparing a positive electrode active material mixture containing a lithium composite oxide; separating lithium from the positive electrode active material mixture to form a primary transition metal precursor; subjecting the primary transition metal precursor to an acid treatment to form a composite transition metal salt solution; adding an acidic extractant to the composite transition metal salt solution, and then adding an alkaline compound to recover the transition metal precursor, thereby improving the extraction rate of the transition metal.

Description

Technical Field

[0001] The present invention relates to a method for recovering a positive electrode active material precursor, and more particularly to a method for recovering a positive electrode active material precursor from a positive electrode active material mixture. Background Art

[0002] With the development of information technology and display technology, secondary batteries that can be repeatedly charged and discharged have been widely used as power sources for mobile electronic devices such as camcorders, mobile phones, and laptop computers. Secondary batteries include, for example, lithium secondary batteries, nickel-cadmium batteries, and nickel-hydrogen batteries. Lithium secondary batteries have attracted much attention due to their high operating voltage and energy density per unit weight, high charging rate, and compact size.

[0003] The lithium secondary battery may include an electrode assembly (including a positive electrode, a negative electrode, a separator layer (separator)) and an electrolyte that immerses the electrode assembly. The lithium secondary battery may further include a case having, for example, a pouch shape for accommodating the electrode assembly and the electrolyte.

[0004] The lithium composite oxide can be used as a positive electrode active material of a lithium secondary battery. The lithium composite oxide may additionally contain a transition metal such as nickel, cobalt, manganese, and the like.

[0005] The lithium composite oxide as a positive electrode active material may be prepared by reacting a lithium precursor with a nickel-cobalt-manganese (NCM) precursor containing nickel, cobalt, and manganese.

[0006] Since the above-mentioned high-cost valuable metals are used as positive electrode active materials, the production cost of manufacturing positive electrode materials is more than 20%. In addition, since environmental protection issues have received attention recently, the recycling method of positive electrode active materials is being studied. In order to recycle positive electrode active materials, it is necessary to regenerate lithium precursors from waste positive electrodes with high efficiency and high purity.

[0007] For example, Korean Published Patent Application No. 2015-0002963 discloses a method for recovering lithium using a wet process. However, lithium is recovered from waste liquid remaining after extracting cobalt, nickel, etc. by wet extraction, so the recovery rate is excessively reduced and a large amount of impurities may be generated from the waste liquid. Summary of the invention

[0008] [Technical goals]

[0009] According to one aspect of the present invention, there is provided a method for recovering a cathode active material precursor from a cathode active material mixture with high purity, high yield and high efficiency.

[0010] [Technical means]

[0011] A method for recovering a positive electrode active material precursor according to an exemplary embodiment of the present invention includes preparing a positive electrode active material mixture containing a lithium composite oxide; separating lithium from the positive electrode active material mixture to form a primary transition metal precursor; subjecting the primary transition metal precursor to an acid treatment to form a composite transition metal salt solution; and adding an acidic extractant to the composite transition metal salt solution, and then adding an alkaline compound to recover the transition metal precursor.

[0012] In some embodiments, forming the primary transition metal precursor may include reducing the cathode active material mixture with hydrogen to form a primary precursor mixture, and washing the primary precursor mixture with water to separate lithium.

[0013] In some embodiments, forming the complex transition metal salt solution may include subjecting the primary transition metal precursor to an acid treatment, such that the pH value of the complex transition metal salt solution may be 0.1-2.0.

[0014] In some embodiments, forming the complex transition metal salt solution may include acid-treating the primary transition metal precursor with sulfuric acid.

[0015] In some embodiments, the complex transition metal salt solution may include a sulfate salt of a transition metal complex including at least two transition metals selected from nickel, cobalt, and manganese.

[0016] In some embodiments, the acidic extractant may include at least one selected from the group consisting of a phosphoric acid-based extractant, a phosphate-based extractant, and a phosphine oxide-based extractant.

[0017] In some embodiments, the acidic extractant may further include a diluent.

[0018] In some embodiments, the diluent may include at least one selected from kerosene, hexane, benzene, and toluene.

[0019] In some embodiments, recovering the transition metal precursor may include mixing the complex transition metal salt solution and the acidic extractant such that the ratio of the organic phase to the aqueous phase may be 2-10.

[0020] In some embodiments, recovering the transition metal precursor may include adding a basic compound to the mixture of the complex transition metal salt solution and the acidic extractant so that the equilibrium pH may be 3.5-6.

[0021] In some embodiments, the basic compound may include at least one selected from lithium hydroxide, sodium hydroxide, and potassium hydroxide.

[0022] [Effects of the Invention]

[0023] According to an exemplary embodiment of the present invention, a primary transition metal precursor obtained by separating a lithium precursor from a positive active material mixture may be acid-treated, and then a high-purity transition metal precursor may be obtained with high yield and high efficiency using an acidic extractant and a basic compound.

[0024] After the lithium precursor is separated from the positive electrode active material mixture, the transition metal precursor can be recovered, so that the transition metal precursor can be extracted at a high equilibrium pH value. Therefore, the recovery rate of the transition metal (eg, nickel) can be improved.

[0025] Furthermore, the transition metals may not be extracted individually but may be extracted in the form of a composite transition metal precursor in a single batch. Thus, the extraction efficiency may be improved.

[0026] [Embodiment for carrying out the present invention]

[0027] According to the exemplary embodiment of the present invention, the transition metal precursor may be recovered using an acidic extractant and a basic compound after previously separating a lithium precursor from a positive active material mixture, and thus the positive active material precursor may be recovered with high yield and high efficiency.

[0028] The term "precursor" in the present application is used to generally refer to a compound containing a specific metal to provide the specific metal contained in the electrode active material.

[0029] In the method of recovering a positive active material precursor according to some embodiments, a positive active material mixture including a lithium composite oxide may be prepared.

[0030] In an exemplary embodiment, the positive electrode active material mixture can be obtained from waste lithium secondary batteries. Waste lithium secondary batteries may include lithium secondary batteries that are substantially no longer usable (charged / discharged). For example, the waste lithium secondary batteries may be lithium secondary batteries whose charge / discharge efficiency is greatly reduced due to end of life, or lithium secondary batteries that are damaged due to impact or chemical reaction.

[0031] The waste lithium secondary battery may include, for example, an electrode assembly including a positive electrode, a negative electrode, and a separator layer between the positive electrode and the negative electrode. For example, the positive electrode and the negative electrode may include a positive electrode active material layer coated on a positive electrode current collector and a negative electrode active material layer coated on a negative electrode current collector, respectively.

[0032] For example, the positive electrode active material included in the positive electrode active material layer may include an oxide containing lithium and a transition metal.

[0033] In some embodiments, the positive active material may be an NCM-based lithium oxide including nickel, cobalt, and manganese. However, embodiments of the present invention are generally applicable to positive electrode materials including NCM-based lithium oxide and lithium-containing positive electrode materials.

[0034] For example, the waste positive electrode can be recycled by separating the positive electrode from the waste lithium secondary battery. The positive electrode may include a positive electrode current collector (eg, aluminum (Al)) and a positive electrode active material layer as described above, and the positive electrode active material layer may include a conductive material and a binder as well as the above positive electrode active material.

[0035] The conductive material may include, for example, a carbon-based material such as graphite, carbon black, graphene, carbon nanotubes, etc. The binder may include a resin material such as polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, etc.

[0036] For example, the positive electrode active material mixture can be prepared from the recycled positive electrode. The term "positive electrode active material mixture" as used herein refers to a mixture in which the positive electrode current collector component (e.g., aluminum) has been substantially completely separated and removed from the recycled positive electrode, and the content of the carbon-based component derived from the conductive material and the binder has been removed or reduced.

[0037] In some embodiments, the positive electrode active material mixture can be obtained in powder form by physical treatment such as pulverization of the recovered positive electrode. As described above, the positive electrode active material mixture may include lithium transition metal oxide powder, such as NCM-based lithium oxide powder (e.g., Li(NCM)O 2 ).

[0038] In some embodiments, the recovered positive electrode may be heat treated before the pulverization process. Thus, during the pulverization process, the separation of the positive electrode collector may be promoted, and the binder and the conductive material may be at least partially removed. The temperature of the heat treatment may be, for example, about 100°C to 500°C, preferably about 350°C to 450°C.

[0039] In some embodiments, the positive electrode active material mixture can be obtained after immersing the recovered positive electrode in an organic solvent. For example, the recovered positive electrode can be immersed in an organic solvent to separate and remove the positive electrode current collector, and the positive electrode active material mixture can be selectively extracted by centrifugal separation.

[0040] Through the above process, a positive electrode active material mixture in which the contents of the positive electrode current collector component and the carbon-based component derived from the conductive material and / or the binder have been substantially removed or reduced can be obtained.

[0041] The positive electrode active material mixture may include, for example, a lithium-containing compound in a positive electrode active material for an electrochemical device. For example, a lithium composite oxide may be used as the positive electrode active material mixture.

[0042] For example, the lithium composite oxide may include lithium and a transition metal, such as nickel, cobalt, or manganese.

[0043] In some embodiments, the lithium composite oxide may be represented by Chemical Formula 1 below.

[0044] [Chemical formula 1]

[0045] Li x Ni a Co b M (1-a-b) O y

[0046] In Chemical Formula 1, M may be selected from Mn, Na, Mg, Ca, Ti, V, Cr, Cu, Zn, Ge, Sr, Ag, Ba, Zr, Nb, Mo, Al, Ga, and B, and 0 <x≤1.1,2≤y≤2.02,0.5≤a≤1,0≤b≤0.5。

[0047] In the exemplary embodiment, the lithium composite oxide having a Ni content of 0.5 mol ratio or more may be effectively converted into the lithium composite oxide.

[0048] As non-limiting examples, the positive active material mixture may further include various lithium-containing compounds, such as lithium oxide, lithium carbonate, lithium hydroxide.

[0049] In some embodiments, lithium can be separated from the prepared positive electrode active material mixture to form a primary transition metal precursor. For example, lithium can be separated from the positive electrode active material mixture in the form of lithium oxide or lithium hydroxide.

[0050] In an exemplary embodiment, the forming of the primary transition metal precursor may include reducing the positive active material mixture to form a primary precursor mixture, and washing the primary precursor mixture with water to separate lithium.

[0051] For example, the primary positive active material mixture may be subjected to hydrogen reduction treatment to form a primary precursor mixture, and then the primary precursor mixture may be washed with water to separate the lithium precursor including lithium hydroxide.

[0052] In some embodiments, a fluidized bed reactor may be used for hydrogen reduction treatment. For example, the positive electrode active material mixture may be introduced into a fluidized bed reactor, and hydrogen may be injected from the bottom of the fluidized bed reactor.

[0053] A cyclone may be formed from the bottom of the fluidized bed reactor by hydrogen, and a primary precursor mixture may be generated while the cathode active material mixture and the hydrogen are in contact with each other.

[0054] In some embodiments, the carrier gas and hydrogen can be mixed and injected at the bottom of the fluidized bed reactor. Therefore, gas-solid mixing can be promoted to enhance the reaction in the fluidized bed, and a reaction layer of the primary precursor mixture in the fluidized bed reactor can be easily formed.

[0055] The carrier gas may include, for example, an inert gas such as nitrogen (N 2 ) or argon (Ar).

[0056] The primary precursor mixture may include, for example, a hydrogen reduction product of a lithium-transition metal oxide contained in the positive active material mixture. If NCM-based lithium oxide is used as the lithium-transition metal oxide, the primary precursor mixture may include a primary lithium precursor and a primary transition metal precursor.

[0057] The primary lithium precursor may include lithium hydroxide, lithium oxide and / or lithium carbonate.

[0058] The transition metal component of the primary transition metal precursor can be derived from the lithium composite oxide in the recovered positive electrode. For example, in the reaction of converting the lithium composite oxide into lithium oxide, the transition metal component can be separated to form the primary transition metal precursor. The primary transition metal precursor can include, for example, Ni, Co, NiO, CoO, MnO, etc.

[0059] The hydrogen reduction reaction may be performed at a temperature of about 400°C to 700°C, preferably about 450°C to 550°C.

[0060] The primary lithium precursor can be converted into a lithium precursor consisting essentially of lithium hydroxide by a washing process. For example, the mixed lithium oxide and lithium carbonate in the primary lithium precursor can be converted into lithium hydroxide by reacting with water, or can be removed by a washing process. Therefore, a high-purity lithium precursor converted into a desired lithium hydroxide form can be produced.

[0061] The primary lithium precursor may be dissolved by reaction with water to essentially produce an aqueous lithium hydroxide solution.

[0062] The primary transition metal precursor contained in the primary precursor mixture can be precipitated by the washing treatment without being dissolved in water or reacting in water. Therefore, a lithium precursor containing high-purity lithium hydroxide can be obtained and separated from the primary transition metal precursor by filtration.

[0063] In some embodiments, the scrubbing process may be performed while excluding carbon dioxide (CO 2 ). For example, the washing process can be carried out without CO 2atmosphere (e.g., removal of CO 2 The reaction is carried out in an air atmosphere) to prevent the regeneration of lithium carbonate.

[0064] In one embodiment, the water provided during the scrubbing process may be a water lacking CO 2 Gas purge (e.g., nitrogen purge) to produce CO-free 2 atmosphere.

[0065] In some embodiments, the primary transition metal precursor can be treated with an acid to form a complex transition metal salt solution. For example, the complex transition metal salt solution can be an acidic salt solution in which the primary transition metal precursor and the acid react, and when sulfuric acid is used, it can include a complex transition metal sulfate solution.

[0066] For example, the complex transition metal salt solution may include nickel, cobalt or manganese. For example, the complex transition metal salt solution may refer to an acidic salt solution of a complex of two or more transition metals selected from nickel, cobalt and manganese.

[0067] In an exemplary embodiment, the acid treatment can be carried out by placing the primary transition metal precursor in a sulfuric acid solution at a temperature of about 50° C. to 90° C. for about 60-500 minutes. For example, the average pH value of the composite transition metal salt solution formed by the acid treatment can be about 0.1-2.0. Within the above temperature, time and pH range, the composite transition metal salt solution can be more easily formed. In addition, the extraction efficiency of the transition metal can be improved.

[0068] For example, the solid-to-liquid ratio of the acid used for the acid treatment of the primary transition metal precursor may be about 140 g / L or less. More preferably, the solid-to-liquid ratio may be about 90 g / L to 130 g / L.

[0069] For example, the concentration of the acid used for the acid treatment of the primary transition metal precursor may be above about 1.8 M. More preferably, the concentration of the acid may be about 1.8 M to 10 M.

[0070] Within the range of solid-liquid ratio and acid concentration, a complex transition metal salt solution can be formed without adding a redox agent, and thus a high-purity transition metal complex can be recovered efficiently.

[0071] In some embodiments, the complex transition metal precursor can be recovered by adding an acidic extractant to the complex transition metal salt solution and then adding a basic compound.

[0072] In some exemplary embodiments, the acidic extractant may include at least one selected from the group consisting of a phosphoric acid-based extractant, a phosphate ester-based extractant, and a phosphine oxide-based extractant.

[0073] For example, the acidic extractant may include at least one selected from di-2-ethylhexyl phosphoric acid, bis(2,4,4-trimethylpentyl)phosphinic acid, bis(2,4,4-trimethylpentyl)dithiophosphinic acid, 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester, tributyl phosphate and trioctylphosphine oxide. More preferably, the acidic extractant may include di-2-ethylhexyl phosphoric acid. For example, the acidic extractant may increase the ratio (e.g., transition metal extraction rate) of extracting transition metals from a composite transition metal salt solution.

[0074] In some exemplary embodiments, the acidic extractant may further include a diluent. For example, the diluent may be an organic solvent. For example, the organic solvent may include at least one selected from kerosene, hexane, benzene and toluene. More preferably, the organic solvent may include kerosene.

[0075] In some exemplary embodiments, the composite transition metal salt solution and the acidic extractant may be mixed so that the ratio of the organic phase to the aqueous phase (organic phase / aqueous phase) is 2 to 10. More preferably, the composite transition metal salt solution and the acidic extractant may be mixed so that the ratio of the organic phase / aqueous phase is 3 to 7. For example, within the ratio of the organic phase to the aqueous phase, the ratio of the organic phase / aqueous phase may be appropriate so that the separation efficiency of the composite transition metal precursor extracted per unit time may be further improved.

[0076] In some exemplary embodiments, a basic compound may be added to the mixture so that the equilibrium pH of the mixture of the composite transition metal salt solution and the acidic extractant may be about 3.5-6. For example, lithium has been separated in the composite transition metal salt solution, and the content of lithium is reduced, so that transition metal extraction can be performed in a relatively high pH range. Therefore, the extraction rate of transition metals, especially nickel and cobalt, can be improved.

[0077] For example, when the equilibrium pH of the mixture of the complex transition metal salt solution and the acidic extractant is less than the above-mentioned equilibrium pH range, the extraction rate of the transition metal may be reduced.

[0078] For example, if the equilibrium pH value of the mixture of the composite transition metal salt solution and the acidic extractant exceeds the above range, side reactions such as metal precipitation may occur. In addition, as the average pH value of the composite transition metal salt solution increases, the loading amount of the metal in the organic phase may increase, thereby increasing the density and viscosity of the solution. Therefore, due to the high density and high viscosity of the solution, the fluidity of the organic phase may decrease, and the phase separation efficiency from the aqueous phase may decrease.

[0079] In some exemplary embodiments, the basic compound may include at least one selected from lithium hydroxide, sodium hydroxide, and potassium hydroxide.

[0080] For example, the percentage concentration of the basic compound may be about 10% to 60%. Within the percentage concentration range of the basic compound, the equilibrium pH value of the mixture of the complex transition metal salt solution and the acidic extractant can be easily adjusted.

[0081] In the exemplary embodiment, a cathode active material precursor may be prepared, and a transition metal hydroxide may be obtained by appropriate treatment of the cathode active material precursor, which may be used to prepare a cathode active material.

[0082] Hereinafter, preferred embodiments are proposed to more specifically describe the present invention. However, the following examples are given only to illustrate the present invention, and those skilled in the relevant art will clearly understand that these examples do not limit the appended claims, and various changes and modifications can be made within the scope and spirit of the present invention. Such changes and modifications are appropriately included in the appended claims.

[0083] Example 1

[0084] 1 kg of the positive electrode material recovered from the waste lithium secondary battery was heat treated at 450°C, cut into subunits and crushed by grinding. The crushed positive electrode material was filtered through a sieve with a mesh size of 80 μm to remove the positive electrode current collector component (Al) and carbon-based impurities, thereby obtaining a positive electrode active material mixture.

[0085] 10 g of the positive electrode active material mixture was charged into a column-type hydrogen reduction reactor, 20% hydrogen was injected, and the mixture was reacted at 450° C. for 2 hours to obtain a primary precursor mixture.

[0086] The primary precursor mixture was reacted with 100 ml of nitrogen-purged water, filtered through filter paper, and centrifuged to obtain a lithium-containing supernatant and a precipitate containing the primary transition metal precursor.

[0087] After removing the lithium-containing supernatant, the precipitate containing the primary transition metal precursor was dried. 130 g of the dried precipitate was added to 1 L of 2 mol / L sulfuric acid to form a composite transition metal salt solution. The pH value of the obtained composite transition metal salt solution was 0.11.

[0088] An acidic extractant containing 1 mol / L di-2-ethylhexyl phosphoric acid and kerosene is added to the complex transition metal salt solution to form a mixture of the complex transition metal salt solution and the acidic extractant. The organic phase / aqueous phase ratio of the mixture is 6. Thereafter, sodium hydroxide having a percentage concentration of 50% is added to the mixture, and the equilibrium pH value of the mixture is adjusted to 4.74 to extract the complex transition metal precursor.

[0089] Example 2 to Example 8

[0090] The complex transition metal precursor was extracted by the same method as in Example 1, except that the equilibrium pH value and the organic phase / aqueous phase ratio of the mixture of the complex transition metal salt solution and the acidic extractant were adjusted as shown in Table 1 below.

[0091] Comparative Example 1

[0092] 1 kg of the positive electrode material recovered from the waste lithium secondary battery was heat treated at 450°C, cut into subunits and crushed by grinding. The crushed positive electrode material was filtered through a sieve with a mesh size of 80 μm to remove the positive electrode current collector component (Al) and carbon-based impurities, thereby obtaining a positive electrode active material mixture.

[0093] 200 g of the positive electrode active material mixture was added to 1 L of 3 mol / L sulfuric acid, and 10% by volume of H 2 O as a reducing agent with a percentage concentration of 35% relative to the amount of sulfuric acid was added. 2 O 2 , to form a composite transition metal salt solution. The pH value of the composite transition metal salt solution is 0.48.

[0094] An acidic extractant containing 1 mol / L of di-2-ethylhexyl phosphoric acid and kerosene is added to the complex transition metal salt solution to form a mixture of the complex transition metal salt solution and the acidic extractant. The ratio of the organic phase / aqueous phase of the mixture is 6. Thereafter, sodium hydroxide with a percentage concentration of 50% is added to the mixture, and the equilibrium pH value of the mixture is adjusted to 4.7 to extract the complex transition metal precursor.

[0095] Comparative Examples 2 to 4

[0096] The complex transition metal precursor was extracted by the same method as in Comparative Example 1, except that the equilibrium pH value and the organic phase / aqueous phase ratio of the mixture of the complex transition metal salt solution and the acidic extractant were adjusted as shown in Table 1 below.

[0097] [Table 1]

[0098]

[0099]

[0100] Experimental example: Calculation of metal extraction rate

[0101] The extraction rate was calculated by comparing the weight percentage of transition metals present in the aqueous phase before and after extraction. The weight percentage of transition metals present in the aqueous phase before and after extraction and the extraction rate calculated therefrom are shown in Table 2 below.

[0102] [Table 2]

[0103]

[0104] Referring to Table 2 above, as the ratio of the organic phase to the aqueous phase increases, the number of sites from which the metals present in the organic phase can be extracted increases, and thus the extraction rate of the metals increases.

[0105] Referring to Example 5, when the average pH value of the mixture of the complex transition metal salt solution and the acidic extractant exceeds 6.0, the amount of metal extracted increases, thereby increasing the viscosity and density of the extractant, making it difficult to separate from the aqueous phase.

[0106] Referring to Table 2, when the ratio of the organic phase / aqueous phase of the composite transition metal salt solution, the acidic extractant and the alkaline compound is 2-10, and the equilibrium pH range is 3.5-6, the extraction rate of the transition metal is further improved.

Claims

1. A method for recovering a positive electrode active material precursor, comprising: preparing a positive electrode active material mixture containing a lithium composite oxide; Separating lithium from the positive electrode active material mixture to form a primary transition metal precursor; treating the primary transition metal precursor with an acid to form a complex transition metal salt solution; and adding an acidic extractant to the composite transition metal salt solution, and then adding a basic compound to recover the transition metal precursor, wherein the recovering of the transition metal precursor comprises mixing the composite transition metal salt solution and the acidic extractant so that the ratio of the organic phase to the aqueous phase is 6-10, The recovering of the transition metal precursor comprises adding the basic compound to a mixture of the complex transition metal salt solution and the acidic extractant to achieve an equilibrium pH value of 3.5-6.

1. 2 . The method for recovering a cathode active material precursor according to claim 1 , wherein the forming of a primary transition metal precursor comprises reducing the cathode active material mixture with hydrogen to form a primary precursor mixture, and washing the primary precursor mixture with water to separate lithium. 3 . The method for recovering a positive electrode active material precursor according to claim 1 , wherein the forming of the composite transition metal salt solution comprises acid-treating the primary transition metal precursor so that the pH value of the composite transition metal salt solution is 0.1-2.

0. 4 . The method for recovering a positive electrode active material precursor according to claim 1 , wherein the forming of the complex transition metal salt solution comprises subjecting the primary transition metal precursor to an acid treatment using sulfuric acid. 5 . The method for recovering a positive electrode active material precursor according to claim 4 , wherein the complex transition metal salt solution comprises a sulfate of a transition metal complex, wherein the transition metal complex comprises at least two transition metals selected from nickel, cobalt and manganese. 6 . The method for recovering a positive electrode active material precursor according to claim 1 , wherein the acidic extractant comprises at least one selected from a phosphoric acid-based extractant, a phosphate-based extractant, and a phosphine oxide-based extractant. 7 . The method for recovering a positive electrode active material precursor according to claim 1 , wherein the acidic extractant further comprises a diluent. 8 . The method for recovering a positive electrode active material precursor according to claim 7 , wherein the diluent comprises at least one selected from kerosene, hexane, benzene and toluene.

9. The method for recovering a positive electrode active material precursor according to claim 1, wherein the recovering the transition metal precursor comprises adding the alkaline compound to a mixture of the complex transition metal salt solution and the acidic extractant so that the equilibrium pH value is 3.5-6. 10 . The method for recovering a positive electrode active material precursor according to claim 9 , wherein the alkaline compound comprises at least one selected from the group consisting of lithium hydroxide, sodium hydroxide and potassium hydroxide.

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