A recovery method of metal from complex metal oxide containing lithium

Abstract

The present invention relates to a method for extracting metals. The extraction method can extract metal compounds with high efficiency from complex metal oxides containing multiple metals through a simple process without generating waste such as sulfates. Furthermore, since the extracted metal compounds have a low content of impurities such as sulfate ions, they can be usefully utilized as raw materials for lithium secondary batteries.

Description

Technology Field

[0001] The present invention relates to a method for extracting a metal compound from a complex metal oxide comprising a plurality of metals. Background Technology

[0003] Lithium-ion batteries are widely used in various industrial fields due to their advantages, such as high energy density, high electromotive force, and the ability to store high-capacity energy. For example, lithium-ion batteries are used in a wide range of applications, from small portable devices like smartphones and laptops to electric vehicles (EVs) that are expected to replace current fossil fuel vehicles in the future. Accordingly, the production volume of lithium-ion batteries is also gradually increasing.

[0004] The key components of these lithium-ion batteries are lithium, used as the main component of the cathode, and valuable metals such as nickel, cobalt, and manganese. These lithium and valuable metals are generally manufactured from ores and are traded at relatively high prices due to manufacturing costs and the cost of the raw materials themselves. Therefore, to lower the manufacturing cost of lithium-ion batteries, research is being conducted not only on the performance of the batteries themselves but also on methods to recover and reuse metal components wasted during the manufacturing process or from batteries that have reached the end of their lifespan.

[0005] For example, technologies have been developed to recover lithium, nickel, cobalt, manganese, etc., from a leachate obtained by acid-treating black mass derived from waste batteries with an inorganic acid. More specifically, black mass is treated with sulfuric acid, a strong acid, to obtain a leachate in which the aforementioned metals are dissociated, and after recovering transition metals such as nickel, cobalt, and manganese components from the obtained leachate, lithium can be recovered in the form of sulfates.

[0006] However, these conventional technologies generate a significant amount of inorganic salts, such as sodium sulfate (Na2SO4), during the process of converting recovered metal inorganic oxides, such as metal sulfides, into metal compounds that serve as precursors for cathode materials, thereby imposing a high environmental and economic burden on waste disposal. Furthermore, the converted lithium compounds are crystallized through processes such as precipitation; however, since sulfate ions bind to or adsorb within the crystals and precipitate together during the precipitation process, it is difficult to completely remove them even with washing with water or additional purification processes. For this reason, metal compounds recovered from black mass contain sulfuric acid components as impurities, and when using these to manufacture cathode materials, there is a limitation in that the performance of the cathode material is inferior due to the residual sulfuric acid components. Prior art literature

[0008] Republic of Korea Registered Publication No. 10-2085016 The problem to be solved

[0009] Accordingly, the objective of the present invention is to provide a technology that can obtain multiple metal compounds containing lithium and transition metals from waste batteries with high efficiency through a simple process, while minimizing the generation of waste such as sulfates by not using inorganic acids such as strong acids like sulfuric acid. means of solving the problem

[0011] In order to solve the aforementioned problem,

[0012] The present invention is,

[0013] A step (S1) of reacting a mixture of a complex metal oxide containing lithium and a transition metal with a hydroxycarboxylic acid compound to produce a polyvalent carboxylic acid metal salt, and

[0014] A metal extraction method is provided comprising the step (S2) of separating a reaction product containing the above-mentioned polycarboxylic acid metal salt into solid and liquid phases to separate a solution containing the polycarboxylic acid metal salt.

[0015] In the above step (S1), the transition metal of the composite metal oxide may include one or more heterogeneous metals among nickel, cobalt, and manganese.

[0016] In the above step (S1), the mixture may include a solvent in which ammonia is dissolved.

[0017] In the above step (S1), the solvent may contain ammonia in the range of 5 to 20 equivalents based on 1 equivalent of lithium and transition metal contained in the complex metal oxide.

[0018] In the above step (S1), the hydroxycarboxylic acid compound may include one or more of glycolic acid, hydroxypropionic acid, lactic acid, hydroxybutyric acid, citric acid, ricinoleic acid, serine, threonine, and aldonic acid.

[0019] In the above step (S1), the hydroxycarboxylic acid compound may be mixed in a range of 1.1 to 5 equivalents based on 1 equivalent of lithium and transition metal contained in the complex metal oxide.

[0020] The step (S1) of generating the above polycarboxylic acid metal salt may include the step (S1-1) of forming ammonium hydroxycarboxylate by mixing a hydroxycarboxylic acid compound in a solvent in which ammonia is dissolved, and the step (S1-2) of generating the polycarboxylic acid metal salt by mixing and reacting a complex metal oxide with the solution in which the ammonium hydroxycarboxylate is formed.

[0021] In the above step (S1), the reaction of the mixture can be carried out at a temperature in the range of 15°C to 120°C.

[0022] In the above step (S2), lithium polycarboxylate can be precipitated in a pH range of 9 or higher.

[0023] In the above step (S1), the lithium polycarboxylate salt may be one or more of lithium oxalate, nickel oxalate, cobalt oxalate, manganese oxalate, nickel malonate, cobalt malonate, manganese malonate, and lithium malonate.

[0024] In the above step (S1), the composite metal oxide may be obtained from black mass derived from a deactivated battery.

[0026] In addition, the present invention provides a metal salt of a polycarboxylic acid produced by the above extraction method.

[0027] At this time, the lithium polycarboxylate salt may include one or more of lithium oxalate, nickel oxalate, cobalt oxalate, manganese oxalate, nickel malonate, cobalt malonate, manganese malonate, and lithium malonate.

[0029] In addition, the present invention provides an anode active material comprising a lithium complex metal oxide derived from the above polycarboxylic acid metal salt.

[0030] The above lithium complex metal oxide may be a compound represented by the following chemical formula 1:

[0031] [Chemical Formula 1]

[0032] Li x [Ni y Co z Mn w M 1 v ]O2

[0033] In the above chemical formula 1,

[0034] M 1It is one or more elements selected from W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, and

[0035] x, y, z, w, and v are 1.0≤x≤1.30, 0.5≤y<1, 0 <z≤0.3, 0<w≤0.3, 0≤v≤0.1이되, y+z+w+v=1이다.

[0037] Furthermore, the present invention,

[0038] Anode comprising the aforementioned positive electrode active material,

[0039] cathode, and

[0040] A lithium secondary battery comprising a separator disposed between the anode and the cathode is provided. Effects of the invention

[0042] The metal extraction method according to the present invention can extract transition metals, including lithium, nickel, cobalt, and manganese, from a complex metal oxide containing multiple metals with high efficiency through a simple process without generating waste such as sulfates. In addition, since the extracted metal compound has a low impurity content, it can be usefully utilized in the production of precursor compounds for manufacturing raw materials for lithium secondary batteries. Specific details for implementing the invention

[0044] The present invention is capable of various modifications and may have various embodiments, and specific embodiments are to be described in detail in the detailed description.

[0045] However, this is not intended to limit the invention to specific embodiments and should be understood to include all modifications, equivalents, and substitutions that fall within the technical scope of the invention.

[0046] In the present invention, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0047] In addition, "water" in this specification may be industrial water that does not contain metals or non-metals, and specifically, it may be distilled water that has undergone a distillation process at least once or purified water that has been purified through ion exchange, etc.

[0049] The present invention will be described in more detail below.

[0051] Metal extraction method

[0052] The present invention is,

[0053] A step (S1) of reacting a mixture of a complex metal oxide containing lithium and a transition metal with a hydroxycarboxylic acid compound to produce a polyvalent carboxylic acid metal salt, and

[0054] A metal extraction method is provided comprising the step (S2) of separating a reaction product containing the above-mentioned polycarboxylic acid metal salt into solid and liquid phases to separate a solution containing the polycarboxylic acid metal salt.

[0056] The metal extraction method according to the present invention relates to a method for extracting a metal salt of a polycarboxylic acid from a complex metal oxide containing a plurality of metals using a hydroxycarboxylic acid compound.

[0057] Specifically, the metal extraction method comprises the step (S1) of reacting a mixture of a complex metal oxide containing lithium and a transition metal with a hydroxycarboxylic acid compound to produce a polycarboxylic acid metal salt, and the step (S2) of separating a solution containing the polycarboxylic acid metal salt by solid-liquid separation of the reaction product containing the polycarboxylic acid metal salt.

[0059] The above step (S1) refers to the process of generating a polycarboxylic acid metal salt from a complex metal oxide containing a plurality of metals.

[0060] The above-mentioned polycarboxylic acid metal salt refers to a complex compound in which a polycarboxylic acid is bonded to lithium and / or a transition metal as a ligand. To prepare the above-mentioned polycarboxylic acid metal salt, the present invention includes a process of reacting a complex metal oxide comprising a plurality of metals (specifically lithium and a heterogeneous metal other than lithium) with a hydroxycarboxylic acid compound.

[0061] At this time, the composite metal oxide may be obtained from black mass. Here, the black mass may be particles obtained by discharging a deactivated battery, i.e., a waste battery, and crushing the battery itself. In some cases, the black mass may include black powder obtained by separating and crushing only the positive and negative electrodes from the waste battery. In addition to lithium derived from the cathode material, the black mass may contain nickel (Ni), cobalt (Co), manganese (Mn), iron (Fe), aluminum (Al), etc., within a certain content range. Here, the cathode material is LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.9 Co 0.05 Mn 0.05 O2, LiNi 0.6 Co 0.2 Mn 0.1 Al 0.1 O2, LiNi 0.6 Co 0.2 Mn 0.15 Al 0.05 O2, LiNi 0.7 Co 0.1 Mn 0.1 Al 0.1Lithium complex metal oxides such as O2 may be included alone or in combination of two or more types, but are not limited thereto.

[0062] As described above, the above-mentioned composite metal oxide is derived from the cathode material and may include heterogeneous metals such as nickel, cobalt, manganese, and aluminum along with lithium. The above-mentioned composite metal oxide may take the form of a composite metal oxide represented by a single chemical formula, in which lithium and heterogeneous metals are alloyed. Additionally, depending on the case, the above-mentioned composite metal oxide may be in a state in which individual metal oxides, such as lithium oxide (Li2O), nickel oxide (NiO, Ni2O3, etc.), cobalt oxide (CoO, Co2O3, Co3O4, etc.), manganese oxide (MnO, MnO2, MnO3, Mn2O3, Mn2O7, Mn3O4, etc.), and aluminum oxide (Al2O3, etc.), are uniformly mixed.

[0063] The above composite metal oxide may not have high purity as it is derived from black mass. Specifically, the above composite metal oxide may not have high purity as it contains components derived from conductive materials used in the anode other than the anode material, and other additives. The above composite metal oxide may exhibit a purity of 90% or less when performing inductively coupled plasma emission spectroscopy (ICP-OES). For example, the above composite metal oxide may have a purity in the range of 40% to 90%; 50% to 90%; 60% to 90%; or 70% to 90% when performing inductively coupled plasma emission spectroscopy (ICP-OES).

[0064] The above hydroxycarboxylic acid compound can be mixed with a solvent in which ammonia is dissolved prior to being mixed with a complex metal oxide to form ammonium hydroxycarboxylate. Since the ammonium hydroxycarboxylate contains a hydroxyl group within its molecule, it is characterized by significantly superior efficiency in leaching metals contained within the complex metal oxide into a solution compared to general ammonium compounds such as ammonium carbonate and ammonium acetate, or ammonium polycarboxylate. More specifically, the hydroxyl group of the ammonium hydroxycarboxylate can act as a reducing agent that damages the crystal structure of the complex metal oxide to induce the selective release of metal ions. In this process, the hydroxyl group is oxidized and converted into a carboxylic acid group, so the ammonium hydroxycarboxylate can be converted into ammonium polycarboxylate. The above-mentioned polycarboxylate ammonium can act as a reactive substance to produce a polycarboxylate metal salt by reacting with metal ions, including lithium ions and transition metal ions, released from a complex metal oxide. To this end, the present step (S1) may include a step (S1-1) of forming ammonium hydroxycarboxylate by mixing a hydroxycarboxylic acid compound into a solvent in which ammonia is dissolved, and a step (S1-2) of producing a polycarboxylate metal salt by mixing a complex metal oxide into the solution in which the ammonium hydroxycarboxylate is formed and reacting it. Here, the hydroxycarboxylic acid compound can simultaneously perform the role of a reducing agent and a reactive substance for metal ions in step (S1-1) and step (S1-2), respectively.

[0065] The above hydroxycarboxylic acid compound includes a compound comprising one or more carboxylic acid groups and a hydroxyl group capable of acting as a reducing agent. Specifically, the above hydroxycarboxylic acid compound may include one or more of glycolic acid, hydroxypropionic acid, lactic acid, hydroxybutyric acid, citric acid, ricinoleic acid, serine, threonine, and aldonic acid.

[0066] For example, the above hydroxycarboxylic acid compound may include glycolic acid and / or hydroxypropionic acid. The above hydroxycarboxylic acid compound has a high reducing power of the hydroxyl group, so it can effectively induce the release of metal ions, such as lithium ions, from metal oxides. In addition, the polycarboxylic acid compound (specifically, ammonium polycarboxylate) generated in this process has excellent reactivity with the released lithium ions and / or transition metal ions, so it can easily produce a metal salt of polycarboxylate.

[0067] The above hydroxycarboxylic acid compound may be mixed with the complex metal oxide in a range of 1.1 to 5 equivalents based on 1 equivalent, where the total moles of lithium and transition metal contained in the complex metal oxide are defined as 1 equivalent. Specifically, the above hydroxycarboxylic acid compound may be mixed with the complex metal oxide in a range of 1.1 to 4 equivalents; 1.1 to 3 equivalents; 1.1 to 2 equivalents; 1.5 to 3 equivalents; 2 to 4 equivalents; 3 to 5 equivalents; 1.5 to 3 equivalents; 1.1 to 1.9 equivalents; 1.2 to 1.8 equivalents; or 1.3 to 1.7 equivalents based on 1 equivalent of lithium and transition metal contained in the complex metal oxide. The present invention can prevent the formation of impurities other than the polycarboxylic acid metal salt due to an excess amount of hydroxycarboxylic acid compound exceeding the upper limit described above by satisfying the equivalent amount of the hydroxycarboxylic acid compound mixed with the complex metal oxide within the above range. In addition, the present invention can prevent the yield of the polycarboxylic acid metal salt from decreasing due to the equivalent amount of the hydroxycarboxylic acid compound falling short of the lower limit described above.

[0068] The mixture of the complex metal oxide and the hydroxycarboxylic acid compound is reacted in a solution state containing a solvent. At this time, the solvent may include ammonia (NH3). The ammonia can stabilize the reaction solution by maintaining it as a weak base, thereby preventing the reduced lithium ions from forming hydroxides. This can promote the reduction of metal ions contained in the complex metal oxide and / or the reaction between the metal ions and the polycarboxylic acid compound. Additionally, the ammonia dissolved in the solvent can act to convert the hydroxycarboxylic acid compound into an ammonium compound before the hydroxycarboxylic acid compound and the complex metal oxide are mixed. In this case, the metal can be leached with higher efficiency compared to the case where the hydroxycarboxylic acid compound directly leaches the metal contained in the complex metal oxide. Furthermore, the ammonium hydroxycarboxylate produced by the reaction with ammonia can stably coordinate with the metal ions eluted from the complex metal oxide to form a complex ion. The above complex ion can further stabilize the metal ion, and thus can promote the leaching of the metal ion.

[0069] The above solvent may contain ammonia in a predetermined content range. Specifically, the solvent may contain ammonia in a range of 5 to 20 equivalents based on 1 equivalent, where the total moles of lithium and transition metal contained in the complex metal oxide are defined as 1 equivalent. For example, the solvent may contain ammonia in a range of 5 to 15 equivalents; 10 to 20 equivalents; 8 to 15 equivalents; or 7 to 12 equivalents based on 1 equivalent of lithium and transition metal contained in the complex metal oxide. By controlling the content of ammonia contained in the solvent to the above-described range, the present invention can prevent the reduction of the precipitation efficiency of the polycarboxylic acid metal salt generated in a subsequent process due to an equivalent amount of ammonia higher than the upper limit. In addition, the present invention can prevent a significant increase in the amount of reducing agent (i.e., hydroxycarboxylic acid compound) required to reduce metal ions in complex metal oxides due to an equivalent amount of ammonia lower than the lower limit.

[0070] The above solvent may include a polar solvent and / or an ionic solvent. The polar solvent may include a solvent capable of forming hydrogen bonds or dipole interactions with ammonia molecules. As an example, the solvent may include water; alkyl alcohols having 1 to 4 carbon atoms, such as methanol or ethanol; acetone, etc. Additionally, the ionic solvent may include liquid ammonia (2NH3), etc., as a solvent with very high polarity and high solubility for ammonia. For example, the solvent used in the present invention may include water. Compared to other organic and / or inorganic solvents, water can dissolve polycarboxylic acid metal salts and ammonia relatively easily.

[0071] Meanwhile, in the above step (S1), the reaction of the mixture may be performed within a predetermined temperature range. Generally, in a composite metal oxide containing a plurality of metals in an alloyed state, the leaching of metal is performed using a reducing agent at a high temperature exceeding 120°C to improve leaching efficiency. However, the step (S1) according to the present invention can leach metal ions from the composite metal oxide under conditions of 120°C or lower without a separate reducing agent. Specifically, the reaction of the above step (S1) may be performed at a temperature in the range of 15°C to 120°C. For example, the reaction of the above step (S1) may be performed at 15°C to 110°C; 15°C to 105°C; 15°C to 100°C; 15°C to 95°C; 15°C to 85°C; 15°C to 75°C; 15°C to 65°C; 15°C to 55°C; 15°C to 45°C; 15°C to 35°C; It can be performed at a temperature in the range of 30℃ to 100℃; 50℃ to 100℃; 75℃ to 100℃; 80℃ to 110℃; 90℃ to 105℃; 60℃ to 105℃; 35℃ to 55℃; 45℃ to 80℃; 55℃ to 90℃; 20℃ to 50℃; 25℃ to 55℃; 15℃ to 45℃; 15℃ to 30℃; 15℃ to 25℃; 20℃ to 40℃; 25℃ to 40℃; 18℃ to 30℃; 18℃ to 25℃; 20℃ to 25℃; or 18℃ to 23℃. The present invention can improve production efficiency while maintaining high purity of the metal salt with polycarboxylic acid by carrying out the reaction between a complex metal oxide and a hydroxycarboxylic acid compound in the temperature range described above.

[0072] The above reaction can be carried out by applying an external force to a mixture of a complex metal oxide and a hydroxycarboxylic acid compound. Here, "external force" may refer to energy artificially applied to induce intermolecular collisions between the complex metal oxide and the hydroxycarboxylic acid compound and / or intermolecular collisions between the metal ions formed therefrom and the polycarboxylic acid compound, specifically between the eluted metal ions and ammonium polycarboxylate.

[0073] Such external forces include mechanical external forces applied by stirring the mixture or physical external forces applied by irradiating the mixture with ultrasound, and these may be applied alone or in combination.

[0074] For example, the above reaction can be carried out by stirring a mixture of a complex metal oxide and a hydroxycarboxylic acid compound at a speed ranging from 100 rpm to 3,000 rpm. Specifically, the above reaction can be carried out by stirring a mixture of a complex metal oxide and a hydroxycarboxylic acid compound at a speed ranging from 100 rpm to 2,000 rpm; 100 rpm to 1,000 rpm; 100 rpm to 900 rpm; 100 rpm to 750 rpm; 100 rpm to 500 rpm; 100 rpm to 300 rpm; 200 rpm to 800 rpm; 300 rpm to 700 rpm; 500 rpm to 1,500 rpm; 1,000 rpm to 2,000 rpm; 500 rpm to 1,000 rpm; or 400 rpm to 600 rpm. The present invention can produce a polyvalent carboxylic acid metal salt with high manufacturing efficiency by performing the reaction of step (S1) under the conditions described above.

[0075] As another example, the above reaction may be carried out by ultrasonically irradiating a mixture of a complex metal oxide and a hydroxycarboxylic acid compound at a frequency in the range of 20 kHz or higher. Specifically, the above reaction may be carried out by ultrasonically irradiating at a frequency in the range of 20 kHz to 60 kHz; 20 to 40 kHz; 30 kHz to 50 kHz; or 20 kHz to 30 kHz. The present invention can induce various physicochemical effects on a mixture of a metal oxide and a hydroxycarboxylic acid compound by carrying out the reaction of step (S1) under the conditions described above. Thus, the rate of production of the polycarboxylic acid metal salt being manufactured can be further improved.

[0077] Next, the above step (S2) refers to the process of separating the polycarboxylic acid metal salt generated in the previous step (S1) into a solution state.

[0078] In the previous step (S1), when a mixture of a complex metal oxide containing lithium and a heterogeneous metal reacts with a hydroxycarboxylic acid compound, a polycarboxylic acid metal salt is produced. The polycarboxylic acid metal salt includes a polycarboxylic acid transition metal salt containing a heterogeneous metal (specifically, nickel, cobalt, and / or manganese) and a polycarboxylic acid lithium salt. At this time, the complex metal oxide remaining after the reaction and / or the metal byproducts generated by the reaction exist in a solid state as precipitates in the solution, and the polycarboxylic acid transition metal salt and the polycarboxylic acid lithium salt may be dissolved in the solution. Accordingly, in the present step (S2), the complex metal oxide (and / or metal byproducts) and the polycarboxylic acid metal salt having different phases can be separated into solid and liquid phases to separate the polycarboxylic acid metal salt into a solution state.

[0079] The above solid-liquid separation can be performed by methods such as centrifugation, flotation, pressurized water separation, bubble separation, electrolytic flotation, oil-water separation, and filtration separation. For example, the above step (S2) can separate a solution in which a polyvalent carboxylic acid metal salt is dissolved through a mesh filter, a cellulose filter, a solid-liquid separator, etc.

[0080] Furthermore, the metal extraction method according to the present invention may further include a step (S3) of obtaining a solid-state polycarboxylic acid metal salt from a solution separated from solid in step (S2).

[0081] This step (S3) refers to a process in which a phase change of the polycarboxylic acid metal salt is performed, and the phase change of the polycarboxylic acid metal salt can be applied without particular limitation as long as it is a method commonly applied in the industry. For example, the polycarboxylic acid metal salt can be obtained in a solid state through crystallization after concentrating a solution in which solid and liquid have been separated.

[0082] Specifically, the solvent in the solid-liquid separated solution may be removed and / or concentrated by one or more methods of electro-deionization, reverse osmosis, thermal evaporation, solar evaporation, solar-thermal evaporation, concentrated solar evaporation, evaporation pond, vacuum distillation, vacuum distillation, multi-stage flash distillation, multi-effect distillation, vapor-compression distillation, freeze-thaw method, electrodialysis, electrodialysis reversal, membrane distillation, membrane dehydration system, chemical absorption, and chemical coordination.

[0083] Additionally, the solvent-removed or concentrated solution may crystallize and precipitate a metal salt of polycarboxylate. The precipitated metal salt of polycarboxylate can be separated from the concentrated solution using a mesh filter, a cellulose filter, a solid-liquid separator, etc. The solid lithium salt of polycarboxylate thus separated can be washed with water and then finally dried using an evaporator, a crystallizer, a dryer, a continuous dryer, a vacuum dryer, or a combination thereof, and then collected.

[0085] The metal extraction method according to the present invention has the advantage of being able to extract metal compounds from complex metal oxides with high efficiency through a simple process without generating waste such as sulfates by having the above-described configuration.

[0087] The polycarboxylic acid metal salt produced by the above manufacturing method is manufactured under conditions that do not use inorganic acids such as sulfuric acid, and thus has the characteristic of having significantly low levels of impurities such as sulfate ions. Therefore, the above polycarboxylic acid metal salt can be easily applied to the cathode material of a secondary battery that requires a high-purity metal compound.

[0088] At this time, the polyvalent carboxylic acid metal salt is a compound in which lithium and / or a transition metal is coordinately bonded to a polyvalent carboxylic acid, and may include one or more of lithium oxalate, nickel oxalate, cobalt oxalate, manganese oxalate, nickel malonate, cobalt malonate, manganese malonate, and lithium malonate.

[0089] For example, when glycolic acid is used as a hydroxycarboxylic acid compound, the polycarboxylic acid metal salt may include lithium oxalate, nickel oxalate, cobalt oxalate, and / or manganese oxalate. If the polycarboxylic acid metal salt is not included as a specific polycarboxylic acid metal salt alone, it may be in a mixed state at a predetermined content ratio.

[0090] In addition, when hydroxypropionic acid is used as the hydroxycarboxylic acid compound, the polycarboxylic acid metal salt may include nickel malonate, cobalt malonate, manganese malonate, and lithium malonate. If the polycarboxylic acid metal salt is not included as a specific polycarboxylic acid metal salt alone, it may have a mixed state in a predetermined content ratio.

[0092] positive electrode active material

[0093] In addition, the present invention provides an anode active material derived from a polycarboxylic acid metal salt produced by the manufacturing method described above.

[0095] The cathode active material of the present invention may mean that it is prepared using a metal salt of a polycarboxylic acid prepared by the extraction method described above as a metal precursor. Specifically, the cathode active material may be prepared using one or more of a lithium compound, a nickel compound, a cobalt compound, and a manganese compound obtained using a metal salt of a polycarboxylic acid prepared according to the metal extraction method of the present invention.

[0096] The above-mentioned cathode active material may include a lithium complex metal oxide containing transition metals such as nickel, cobalt, and manganese along with lithium.

[0097] Specifically, the cathode active material may include a compound represented by the following chemical formula 1:

[0098] [Chemical Formula 1]

[0099] Li x [Ni y Co z Mn w M 1 v ]O2

[0100] In the above chemical formula 1,

[0101] M 1It is one or more elements selected from W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, and

[0102] x, y, z, w, and v are 1.0≤x≤1.30, 0.5≤y<1, 0 <z≤0.3, 0<w≤0.3, 0≤v≤0.1이되, y+z+w+v=1이다.

[0104] The lithium composite metal oxide represented by Chemical Formula 1 above is a compound having a layered crystal structure; since it facilitates the storage of lithium ions and possesses a high lithium ion diffusion rate, it is applied as a cathode active material for high-capacity / high-output secondary batteries. Depending on the case, the lithium composite metal oxide represented by Chemical Formula 1 may contain other transition metals (M 1 It can have a doped form. For example, the lithium composite metal oxide is LiNiO2, Li(Ni 0.6 Co 0.1 Mn 0.3 )O2, Li(Ni 0.6 Co 0.2 Mn 0.2 )O2, Li(Ni 0.7 Co 0.15 Mn 0.15 )O2, Li(Ni 0.8 Co 0.1 Mn 0.1 )O2, Li(Ni 0.9 Co 0.05 Mn 0.05 )O2, Li(Ni 0.6 Co 0.2 Mn 0.1 Zr 0.1 )O2, Li(Ni 0.6 Co 0.2 Mn 0.15 Zr 0.05 )O2, Li(Ni 0.7 Co 0.1 Mn 0.1 Zr 0.1 )O2, Li(Ni 0.6 Co 0.2 Zr 0.2 )O2, Li(Ni0.6 Co 0.2 Al 0.2 )O2, Li(Ni 0.7 Co 0.15 Al 0.15 )O2, Li(Ni 0.8 Co 0.1 Al 0.1 )O2, Li(Ni 0.9 Co 0.05 Al 0.05 )O2, Li(Ni 0.6 Co 0.2 Mn 0.1 Al 0.1 )O2, Li(Ni 0.6 Co 0.2 Mn 0.15 Al 0.05 )O2, Li(Ni 0.7 Co 0.1 Mn 0.1 Al 0.1 )O2, Li(Ni 0.6 Co 0.2 Al 0.1 Zr 0.1 )O2, Li(Ni 0.6 Co 0.2 Al 0.15 Zr 0.05 )O2 and Li(Ni 0.7 Co 0.1 Al 0.1 Zr 0.1 It may include one or more types of )O2, but is not limited thereto.

[0105] The above-mentioned cathode active material is derived from a high-purity polycarboxylic acid metal salt produced according to the present invention, and can achieve physical properties equivalent to or superior to those of a cathode active material produced using a metal precursor derived from raw ore such as lithium, nickel, cobalt, and manganese mined from conventional mines.

[0106] In addition, the above-mentioned cathode active material is derived from black mass or black powder obtained from spent lithium batteries; or from metal salts of polycarboxylic acids recovered from defective materials, scrap, and process residues generated during the cathode active material or cathode manufacturing process, thus offering the advantages of being very economical and environmentally friendly.

[0108] lithium secondary battery

[0109] Furthermore, the present invention,

[0110] Anode comprising the anode active material of the present invention described above,

[0111] cathode, and

[0112] A lithium secondary battery comprising a separator disposed between the anode and the cathode is provided.

[0114] The above lithium secondary battery has the advantages of being very economical and environmentally friendly by including a positive active material derived from a polycarboxylic acid metal salt manufactured according to the present invention.

[0116] The present invention will be explained in more detail below through examples and experimental examples.

[0117] However, the following examples and experimental examples are merely illustrative of the present invention, and the content of the present invention is not limited to the following examples and experimental examples.

[0119] Examples 1 and 2. Preparation of metal salts of polycarboxylic acids

[0120] LiNi as a cathode material 0.6 Co 0.2 Mn 0.2 A black mass derived from an inert lithium secondary battery cell containing O2 is prepared, and from the prepared black mass, a complex metal oxide (average particle size (D)) containing lithium (Li), nickel (Ni), cobalt (Co), and manganese (Mn) is prepared. 50 ): Approximately 0.5~5㎛) was recovered.

[0121] After dispersing about 1 g of the above composite metal oxide in purified water, inductively coupled plasma emission spectroscopy (ICP-OES) was performed to measure the concentration of metals contained in the composite metal oxide. The content of each metal was calculated from the measured concentration. As a result, it was found that the metals contained in the composite metal oxide were lithium (Li), nickel (Ni), cobalt (Co), and manganese (Mn), and their contents were confirmed to be 0.08 g, 0.56 g, 0.03 g, and 0.04 g, respectively.

[0122] 3.44 g of water was injected into the reactor, 500 g of the previously prepared composite metal oxide was added, and then 12.4 g of ammonia water with a concentration of 28 wt% was added to the reactor.

[0123] Separately, an aqueous solution of ammonium glycolate was prepared by mixing 3.78 g of glycolic acid, a hydroxycarboxylic acid compound, with 6.2 g of water ammonia having a concentration of 28 wt%.

[0124] The prepared aqueous ammonium glycolate solution was introduced into a reactor into which a complex metal oxide was introduced. At this time, the equivalents of ammonium glycolate and ammonia finally introduced into the reactor were 4.4 equivalents and 8.8 equivalents, respectively, with respect to 1 equivalent of lithium and transition metal, when the total moles of lithium and transition metal contained in the complex metal oxide were defined as 1 equivalent.

[0125] Subsequently, a mixture of complex metal oxide and ammonium glycolate was reacted (S1) for 10 ± 1 hour at a speed in the range of 500 ± 50 rpm under the temperature conditions shown in Table 1 below using an impeller mounted on the reactor. When stirring was finished, the residual metal oxide precipitated in the reaction mixture and the filtrate were separated (S2) by filtration using a vacuum filter. The separated filtrate was subjected to vacuum distillation to obtain metal oxalates containing lithium, nickel, cobalt, and manganese. The obtained metal oxalates were dried in a vacuum drying oven at 100°C.

[0126] Approximately 1 g each of residual metal oxide and dried metal oxalate obtained from the previous filtration using a vacuum filter were dispersed in purified water, and then inductively coupled plasma emission spectroscopy (ICP-OES) was performed to measure the concentrations of lithium (Li), nickel (Ni), cobalt (Co), and manganese (Mn) contained in each material. The recovery rate of the metals contained in each material was calculated from the measured metal concentrations, and the results are shown in Table 1 below.

[0127] Reaction temperature of step (S1) Metal recovery rate [%] Li Ni Co Mn Example 1 25±2℃ 48 42 43 5 Example 2 100±2℃ 98 89 92 5

[0129] As shown in Table 1 above, it can be seen that the metal extraction method according to the present invention can recover metal salts of polycarboxylic acids with high efficiency from complex metal oxides containing lithium, nickel, cobalt, and manganese. In addition, it was confirmed that the prepared metal salts of polycarboxylic acids have a significantly low content of impurities such as sulfuric acid.

[0131] Comparative Examples 1–4. Preparation of metal salts of polycarboxylic acids

[0132] Composite metal oxide identical to Example 1 (average particle size (D 50 ): Approximately 0.5~5㎛) was prepared. The prepared composite metal oxide was introduced into a reactor.

[0133] 3.44 g of water was injected into the reactor, and the compound shown in Table 2 below was added in the corresponding amount in place of the hydroxycarboxylic acid compound, and then 12.4 g of ammonia water with a concentration of 28 wt% was added to the reactor. At this time, the equivalents of each compound and ammonia added to the reactor were adjusted to 4.4 equivalents and 8.8 equivalents, respectively, with respect to 1 equivalent of lithium and transition metal, where the total moles of lithium and transition metal contained in the complex metal oxide are defined as 1 equivalent.

[0134] Subsequently, the mixture in the reactor was reacted (S1) for 10 ± 1 hour at a speed in the range of 500 ± 50 rpm at 25 ± 2℃ using an impeller mounted on the reactor. When stirring was finished, the residual metal oxide precipitated in the reaction mixture and the filtrate were separated (S2) by filtration using a vacuum filter. The separated filtrate was subjected to vacuum distillation to obtain metal oxalates containing lithium, nickel, cobalt, and manganese. Then, the obtained metal oxalates were dried in a vacuum drying oven at 100℃.

[0135] Approximately 1 g each of residual metal oxide and metal oxalate obtained from the previous filtration using a vacuum filter were dispersed in purified water, and then inductively coupled plasma emission spectroscopy (ICP-OES) was performed to measure the concentrations of lithium (Li), nickel (Ni), cobalt (Co), and manganese (Mn) contained in each material. The recovery rate of the metals contained in each material was calculated from the measured metal concentrations, and the results are shown in Table 2 below.

[0136] Added compound Metal recovery rate [%] type Content Li Ni Co Mn Comparative Example 1 ammonium carbonate 2.39 g 75 5 5 <1 Comparative Example 2 ammonium acetate 3.83 g 11 2 8 <1 Comparative Example 3 ammonium oxalate 3.53 g 35 8 5 <1 Comparative Example 4 Ethylene glycol 3.78 g 8 5 5 <1

[0138] As shown in Table 2 above, when ammonium compounds or polyhydric alcohol compounds are used instead of hydroxycarboxylic acid compounds, it can be seen that the leaching rate (or recovery rate) of the metal contained in the complex metal oxide is significantly low. In addition, it can be confirmed that the purity of the recovered metal oxalate is not high.

[0140] From these results, the metal extraction method according to the present invention can extract metal salts of polyvalent carboxylates from complex metal oxides containing multiple metals with high efficiency through a simple process without generating waste such as sulfates. In addition, since the extracted lithium compound has a low impurity content, it can be usefully used as a raw material for lithium secondary batteries, etc.

[0142] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art or those with ordinary knowledge in the art will understand that various modifications and changes can be made to the present invention without departing from the technical scope of the invention as described in the claims set forth below.

[0143] Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be determined by the claims.

Claims

Claim 1 A metal extraction method comprising the step (S1) of reacting a mixture of a complex metal oxide containing lithium and a transition metal with a hydroxycarboxylic acid compound to produce a polycarboxylic acid metal salt, and the step (S2) of separating a reaction product containing the polycarboxylic acid metal salt from a solid to a liquid to separate a solution containing the polycarboxylic acid metal salt, wherein in the step (S1), the transition metal of the complex metal oxide includes one or more heterogeneous metals selected from nickel, cobalt, and manganese, and the mixture of the step (S1) includes a solvent in which ammonia is dissolved. Claim 2 A metal extraction method according to claim 1, wherein the solvent of step (S1) comprises ammonia in the range of 5 to 20 equivalents based on 1 equivalent of lithium and transition metal contained in the complex metal oxide. Claim 3 A metal extraction method according to claim 1, wherein the hydroxycarboxylic acid compound of step (S1) comprises one or more of glycolic acid, hydroxypropionic acid, lactic acid, hydroxybutyric acid, citric acid, ricinoleic acid, serine, threonine, and aldonic acid. Claim 4 A metal extraction method according to claim 1, wherein the hydroxycarboxylic acid compound of step (S1) is mixed in a range of 1.1 to 5 equivalents based on 1 equivalent of lithium and transition metal contained in the complex metal oxide. Claim 5 A metal extraction method according to claim 1, wherein the step (S1) of generating the polycarboxylic acid metal salt comprises: a step (S1-1) of mixing a hydroxycarboxylic acid compound in a solvent in which ammonia is dissolved to form ammonium hydroxycarboxylate, and a step (S1-2) of generating the polycarboxylic acid metal salt by mixing a complex metal oxide into the solution in which ammonium hydroxycarboxylate is formed and reacting it. Claim 6 A metal extraction method according to claim 1, wherein the reaction of the mixture in step (S1) is performed at a temperature in the range of 15°C to 120°C. Claim 7 A metal extraction method according to claim 1, wherein in step (S2), the lithium polycarboxylate is precipitated in a pH range of 9 or higher. Claim 8 A metal extraction method according to claim 1, characterized in that the polycarboxylic acid metal salt of step (S1) is one or more of lithium oxalate, nickel oxalate, cobalt oxalate, manganese oxalate, nickel malonate, cobalt malonate, manganese malonate, and lithium malonate. Claim 9 A metal extraction method according to claim 1, characterized in that the composite metal oxide of step (S1) is obtained from black mass derived from a deactivated battery. Claim 10 A polycarboxylic acid metal salt produced by the manufacturing method according to claim 1. Claim 11 In claim 9, the polyvalent carboxylic acid metal salt comprises one or more of lithium oxalate, nickel oxalate, cobalt oxalate, manganese oxalate, nickel malonate, cobalt malonate, manganese malonate, and lithium malonate. Claim 12 A positive electrode active material comprising a lithium complex metal oxide derived from a polycarboxylic acid metal salt according to claim 10. Claim 13 In claim 12, the cathode active material is characterized in that the lithium complex metal oxide is a compound represented by the following chemical formula 1: [Chemical Formula 1]Li x [Ni y Co z Mn w M 1 v ]O2 In the above chemical formula 1, M 1 ... is one or more elements selected from W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, and x, y, z, w, and v are 1.0≤x≤1.30, 0.5≤y<1, 0 <z≤0.3, 0<w≤0.3, 0≤v≤0.1이되, y+z+w+v=1이다. Claim 14 A lithium secondary battery comprising a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode, the positive electrode having a positive active material according to claim 12.