Method for removing aluminum from black materials derived from waste batteries

Abstract

The present disclosure relates to a method for removing aluminum from a black material derived from a spent battery, in which the aluminum removal method selectively removes aluminum (Al) by performing a heat treatment on a black material derived from a spent battery and a chlorine-based compound precursor, thereby enabling lithium (Li) to be obtained at a high purity and recovery rate. In addition, the aluminum removal method has the advantages of easiness in process control and high safety.

Description

Technical Field

[0001] This disclosure relates to a method for selectively removing aluminum from black matter derived from failed lithium secondary batteries and / or cathode waste.

[0002] This application claims the benefit of Korean Patent Application No. 10-2023-0115629, filed on August 31, 2023, and Korean Patent Application No. 10-2024-0094796, filed on July 18, 2024, the disclosures of which are incorporated herein by reference. Background Technology

[0003] Lithium-ion batteries, primarily used in vehicles, consist of a positive and a negative electrode separated by a separator, and an electrolyte filled between them. The most critical component of these lithium-ion secondary batteries is lithium, the main component used as the positive electrode material. Lithium is typically produced from lithium-containing ores, and due to the costs involved in the manufacturing process and the price of the raw materials themselves, lithium trades at a relatively high price. Therefore, in order to reduce the manufacturing cost of lithium-ion secondary batteries, research has been conducted not only on improving the performance of the batteries themselves, but also on methods for recovering and reusing lithium components from spent lithium-ion batteries.

[0004] To recover lithium from the positive electrode, it must be disassembled and separated from the failed lithium battery to extract the lithium. However, due to the organic materials (e.g., NMP, PVDF) contained in the organic binder, the lithium contained in the positive electrode has poor solubility in various organic solvents and is not easily dissolved even when subjected to ultrasound or filtration.

[0005] Therefore, a wet process has been applied to extract lithium from positive electrode active materials by dissolving pulverized waste battery material (e.g., black material) containing positive electrode active material in an acidic solvent and separating the individual metals. More specifically, the wet process involves discharging the used battery and then grinding the battery itself or the positive electrode separated from the battery. Subsequently, the ground particles are calcined to evaporate / remove non-metallic components, and the remaining material is immersed in an acidic solvent to extract lithium, thereby recovering lithium.

[0006] However, the wet process uses acidic solvents, leading to high costs for treating the waste acidic solvents generated after the wet process is completed, as well as environmental pollution problems caused by byproducts. Furthermore, in the aforementioned method, during the calcination treatment prior to acid treatment, the lithium (Li) component contained in the positive electrode active material and the aluminum (Al) component from the current collector aggregate, easily forming slag. The resulting slag is difficult to selectively separate the lithium (Li) component due to its aluminum (Al) content, and even if separated, the recovery rate is significantly reduced due to impurities.

[0007] [Existing Technology Reference]

[0008] Korean Patent Publication No. 10-2019-0082167 Summary of the Invention

[0009] Technical issues

[0010] Therefore, the purpose of this disclosure is to provide a technique for selectively removing aluminum (Al) from black matter when recovering lithium from failed waste batteries, thereby obtaining lithium (Li) with high purity and recovery rate.

[0011] Technical solution

[0012] To solve the above problems,

[0013] In one implementation, this disclosure provides

[0014] A method for removing aluminum from black material derived from failed batteries, comprising:

[0015] Forming a mixture (S1) containing a black substance and a chlorine-based compound precursor; and

[0016] The resulting mixture is heat-treated to produce a black substance that has undergone dealuminization and aluminum chloride gas (S2).

[0017] The heat treatment is carried out at a temperature above the temperature at which the chlorine-based compound precursor is evaporated or thermally decomposed to produce the chlorine-based compound, but below 300°C.

[0018] Here, the chlorine-based compound precursor may include at least one of the following: a C-type compound in which at least one hydrogen atom is replaced by a chlorine atom. 1-6 Hydrocarbon compounds and polymeric compounds in which at least one hydrogen atom is replaced by a chlorine atom.

[0019] The aforementioned hydrocarbon compounds may include one or more of carbon tetrachloride (CCl4), chloroform (CHCl3), dichloromethane (CH2Cl2), hexachloroethane (C2Cl6), tetrachloroethane (C2H2Cl4), tetrachloroethylene (C2Cl4), and trichloroethylene (C2HCl3).

[0020] In addition, polymer compounds may include polyvinyl chloride (PVC).

[0021] Furthermore, heat treatment can be carried out in a reactor that can maintain the increased internal pressure during heat treatment.

[0022] Furthermore, heat treatment can be carried out at pressures greater than 1 bar and 15 bar or less.

[0023] In addition, the mixture may also contain an aluminum-based catalyst, including aluminum chloride (AlCl3).

[0024] Furthermore, the average particle size of the black material can range from 0.5 μm to 1,000 μm.

[0025] In addition, the black substance may contain aluminum in an amount greater than 0.1% by weight and less than 5% by weight relative to the total weight.

[0026] In addition, the chlorine-based compound precursor can be mixed with the black material such that the ratio of chlorine atoms in the chlorine-based compound precursor to aluminum atoms in the black material (Cl / Al) is 3 to 100, and the heat treatment of the black material and the chlorine-based compound precursor can be carried out for 10 to 50 hours.

[0027] In addition, aluminum removal methods may also include:

[0028] After the production of black dealuminated material and aluminum chloride gas (S2),

[0029] Aluminum chloride gas (S3) was separated from the black material after aluminum removal; and

[0030] The separated aluminum chloride gas is condensed (S4).

[0031] Furthermore, the dealuminated black material can have an aluminum content of 3% by weight or less relative to the total weight.

[0032] Beneficial effects

[0033] The aluminum removal method according to this disclosure selectively removes aluminum (Al) by heat-treating black matter and chlorine-based compound precursors derived from waste batteries under predetermined temperature conditions, thereby allowing the acquisition of lithium (Li) with high purity and recovery rate. Furthermore, the aluminum removal method has the advantages of easy process control and high safety. Attached Figure Description

[0034] Figure 1 and Figure 2 This is a flowchart schematically illustrating an aluminum removal method according to the present disclosure. Detailed Implementation

[0035] Although this disclosure may be modified in different ways and has multiple implementations, the specific implementations will be described in detail below.

[0036] However, it should be understood that this disclosure is not limited to the specific implementations described herein, but includes all modifications, equivalents and alternatives included within the spirit and scope of this disclosure.

[0037] In this disclosure, it should be understood that terms such as “comprising” or “having” are intended to indicate the presence of the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and they do not preclude the possibility of the presence or addition of one or more other features or numbers, steps, operations, components, parts, or combinations thereof.

[0038] Furthermore, in this disclosure, when a portion, such as a layer, film, region, plate, etc., is referred to as being "on" another portion, this includes not only the case where that portion is "directly on" the other portion, but also the case where another portion is located between them. On the other hand, when a portion, such as a layer, film, region, plate, etc., is referred to as being "below" another portion, this includes not only the case where that portion is "directly below" the other portion, but also the case where another portion is located between them. Additionally, in this application, "on" can include both bottom and top locations.

[0039] Furthermore, in this disclosure, "average particle size (D)" 50 "50%" refers to the particle size at which the cumulative value of the particle size distribution is 50%, also known as the median diameter. The average particle size can be measured using methods commonly used in the art. For example, the average particle size can be measured using an analyzer equipped with a laser diffraction particle size distribution measurement method according to ISO 13320.

[0040] The contents of this disclosure will now be described in more detail.

[0041] In one exemplary implementation, this disclosure provides,

[0042] A method for removing aluminum from black material derived from failed batteries, comprising:

[0043] Forming a mixture (S1) containing a black substance and a chlorine-based compound precursor; and

[0044] The resulting mixture is heat-treated to produce a black substance that has undergone dealuminization and aluminum chloride gas (S2).

[0045] The heat treatment is carried out at a temperature above the temperature at which the chlorine-based compound precursor is evaporated or thermally decomposed to produce the chlorine-based compound, but below 300°C.

[0046] This disclosure relates to a method for selectively removing aluminum from the positive electrode current collector of lithium-ion batteries during lithium recovery from failed waste lithium-ion batteries.

[0047] Aluminum removal can be achieved by heat-treating a mixture of lithium-containing material from spent batteries and a chlorine-based compound precursor. Specifically, the aluminum removal method involves the following steps: forming a mixture comprising black material from spent batteries and a chlorine-based compound precursor (S1); and heat-treating the formed mixture to produce dealuminated black material and aluminum chloride gas (S2). The aluminum removal method involves heat-treating the black material from spent batteries and the chlorine-based compound precursor to chlorinate the aluminum contained in the black material. Here, the aluminum chloride (AlCl3) produced during this process undergoes a phase transformation to a gaseous state at approximately 180°C, making it readily volatilizable under high-temperature conditions.

[0048] Therefore, the aluminum removal method according to this disclosure can selectively remove aluminum from black matter by converting aluminum to aluminum chloride (AlCl3) and then volatilizing it. The dealuminated black matter produced in this manner has a significantly reduced aluminum (Al) content, enabling the recovery of lithium (Li) with high purity and recovery rate during lithium recovery processes.

[0049] Figure 1 and Figure 2 This is a flowchart schematically illustrating the process steps of an aluminum removal method according to this disclosure. The following refers to... Figure 1 and Figure 2 Describe each step in more detail.

[0050] First, the aluminum removal method of this disclosure includes forming a mixture of black material and a chlorine-based compound precursor (S1). This step (S1) refers to the process of mixing black material derived from a failed battery with a chlorine-based compound precursor capable of providing a chlorine-based compound to the aluminum (Al) contained in the black material.

[0051] Here, the black substance can be particles obtained by discharging and crushing a failed battery (i.e., a used battery), and may optionally include black powder obtained by separating only the positive electrode from the used battery and crushing it.

[0052] Besides lithium, the black material may also contain valuable metals derived from the positive electrode active material and metals such as aluminum (Al) derived from the positive electrode current collector. Specifically, the black material may originate from a positive electrode formed by a structure in which a positive electrode active layer containing the positive electrode active material is formed on an aluminum foil positive electrode current collector. Therefore, in addition to lithium (Li), the black material may also contain valuable metals such as nickel (Ni), cobalt (Co), manganese (Mn), and iron (Fe), as well as aluminum (Al) within a predetermined concentration range.

[0053] Here, the positive electrode active material may include, alone or in combination, lithium-nickel composite oxides, such as LiNi. 0.8Co 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 0.1 O2, LiNi 0.7 Mn 1.3 O4, LiNi 0.5 Mn 1.5 O4, LiNi 0.3 Mn 1.7 O4, etc.; or lithium iron phosphate, such as LiFePO4, LiFe 0.8 Mn 0.2 PO4, LiFe 0.5 Mn 0.5 PO4, but not limited to this.

[0054] The black material may contain 1% to 10% lithium and 15% to 40% valuable metals (i.e., Ni, Co, Mn) based on the total weight. Furthermore, the black material may contain aluminum in an amount exceeding 0.5% of the total weight, specifically 1% to 5%; 0.5% to 3%; 1% to 3%; 2% to 4%; 2.5% to 5%; or 2.5% to 4.5% aluminum. The remaining portion may consist of a negative electrode active material, such as graphite or silicon, forming the negative electrode of the lithium-ion battery; a metal, such as copper, forming the negative electrode current collector; and an organic material forming the separator.

[0055] The black material can be tuned to have an average particle size within a specific range. Specifically, the black material can have an average particle size (D) of 0.5 μm to 1,000 μm, more specifically, 0.5 μm to 750 μm; 0.5 μm to 500 μm; 0.5 μm to 250 μm; 0.5 μm to 100 μm; 0.5 μm to 50 μm; 0.5 μm to 20 μm; 0.5 μm to 10 μm; 1 μm to 15 μm; 5 μm to 15 μm; 10 μm to 200 μm; 50 μm to 500 μm; 100 μm to 300 μm; 400 μm to 700 μm; 500 μm to 900 μm; 50 μm to 150 μm. 50 ); or it can have an average particle size of 5 μm to 80 μm (D 50 ).

[0056] When the average particle size of the black material is less than the lower limit of the aforementioned range, aggregation of the black material may occur, preventing the chlorination reaction of aluminum present in the aggregated black material from proceeding smoothly. Furthermore, if the average particle size of the black material is greater than the upper limit of the aforementioned range, chlorine may have difficulty penetrating the interior of the black material particles, thus reducing the aluminum removal efficiency.

[0057] Meanwhile, chlorine-based precursors refer to compounds that can provide chlorine-based compounds under high-temperature conditions. Chlorine-based compounds can include hydrocarbon compounds that evaporate and increase their intramolecular energy to activate chlorine atoms, or chlorine (Cl2) gas and / or hydrogen chloride (HCl). Chlorine-based precursors can be substances that are liquid or solid at room temperature (e.g., 18°C ​​to 25°C) and are used to ensure safety and processability during reactions with black substances.

[0058] Specifically, chlorine-based compound precursors may include at least one of the following: C atoms in which at least one hydrogen atom is replaced by a chlorine atom. 1-6 Hydrocarbon compounds; and polymeric compounds in which at least one hydrogen atom is replaced by a chlorine atom.

[0059] The aforementioned hydrocarbon compounds can be compounds in which one or more hydrogen atoms of hydrocarbons having 1 to 6 carbon atoms, such as methane (carbon 1), ethane (carbon 2), and propane (carbon 3), are replaced by chlorine (-Cl). For example, hydrocarbon compounds can include at least one of the following: carbon tetrachloride (CCl4), chloroform (CHCl3), dichloromethane (CH2Cl2), hexachloroethane (C2Cl6), tetrachloroethane (C2H2Cl4), tetrachloroethylene (C2Cl4), trichloroethylene (C2HCl3), etc. Hydrocarbon compounds can be liquid at room temperature (approximately 20 ± 5 °C) and atmospheric pressure (approximately 1 atm).

[0060] Polymer compounds are high molecular weight compounds containing hydrocarbon chains with a molecular weight of 1,000 g / mol or greater, wherein at least one hydrogen atom in the hydrocarbon chain is replaced by a chlorine atom. For example, polymer compounds may include polyvinyl chloride (PVC). Polymer compounds can be solid at room temperature (approximately 20 ± 5 °C) and atmospheric pressure (approximately 1 atm).

[0061] In addition, materials considered suitable as precursors for chlorine-based compounds include chlorine (Cl2) gas, hydrogen chloride (HCl) gas and other gases; dilute hydrochloric acid and other inorganic solvents; metal salts, such as lithium chloride (LiCl), sodium chloride (NaCl), potassium chloride (KCl), calcium chloride (CaCl2); and so on.

[0062] However, gases such as chlorine (Cl2) and hydrogen chloride (HCl) exhibit low reactivity with aluminum in black substances at low temperatures. Furthermore, these gases are difficult to control during the process and are highly toxic to humans, resulting in low safety and making them unsuitable as precursors for chlorine-based compounds.

[0063] Furthermore, inorganic solvents such as dilute hydrochloric acid contain water (H2O). This water reacts with the aluminum (Al) in the black substance before reacting with chlorine (Cl) in chlorine-based compounds to form aluminum oxide (Al2O3). Aluminum oxide undergoes a phase transition to gas at approximately 2977°C, making it difficult to remove aluminum by volatilization. This necessitates additional purification processes to remove it, posing a significant challenge.

[0064] Furthermore, chlorine-containing metal salts undergo a phase transition to a gaseous state at temperatures above approximately 600°C, thus supplying chlorine. This imposes the following limitations: high energy and cost are required during this process to supply chlorine from chlorine-based compound precursors. Additionally, the low reactivity of the metal salts with aluminum (Al) in the black substance and the supplied chlorine (Cl) compound makes it difficult to form aluminum chloride (AlCl3).

[0065] On the other hand, hydrocarbon compounds and / or polymer compounds with chemical structures in which chlorine is substituted in the chain hydrocarbon groups are easier to control during the process and have low toxicity to humans, making them safer. Furthermore, hydrocarbon compounds undergo a phase transition to a gaseous state at temperatures of 200°C or lower, thereby readily supplying the black material with intramolecularly increased chlorine atoms. On the other hand, polymer compounds undergo thermal decomposition at approximately 240°C to 270°C to provide gaseous chlorine (Cl2) and / or hydrogen chloride (HCl). Therefore, hydrocarbon compounds and / or polymer compounds have the characteristic of effectively providing evaporated hydrocarbon compounds comprising gaseous chlorine-based compounds or chlorine (Cl2) and / or hydrogen chloride (HCl). The chlorine-based compounds provided in this way are highly reactive with aluminum (Al) in the black material, rapidly producing aluminum chloride (AlCl3), thus providing the advantage of excellent efficiency in removing aluminum (Al) from the black material.

[0066] The chlorine-based compound precursor can be carbon tetrachloride (CCl4). Carbon tetrachloride (CCl4) has a Gibbs free energy that converts to aluminum chloride (AlCl3) when reacting with aluminum; the Gibbs free energy for converting alumina (Al2O3), which may be produced as a byproduct, to aluminum chloride (AlCl3) is significantly lower, resulting in a negative value. This provides a significant advantage for the chlorination reaction of aluminum.

[0067] Furthermore, chlorine-based compound precursors can be polyvinyl chloride (PVC). PVC possesses high human and process safety characteristics. In addition, PVC is a solid at room temperature, making the material easy to store and manage. Moreover, PVC has the advantage of quantitatively producing gaseous hydrogen chloride (HCl) through thermal decomposition, which is beneficial for process control.

[0068] Furthermore, in this step (S1), the black substance and the chlorine-based compound precursor can be mixed such that the aluminum (Al) atoms contained in the black substance and the chlorine (Cl) atoms contained in the chlorine-based compound precursor have a specific atomic ratio. Specifically, aluminum chloride (AlCl3) has a structure in which one aluminum atom is bonded to three chlorine atoms. Therefore, the chlorine-based compound precursor can be mixed such that the ratio of chlorine atoms to aluminum atoms (Cl / Al) is 3 or greater, and more specifically, the chlorine-based compound precursor can be mixed such that the ratio is from 3 to 100. For example, chlorine-based compound precursors can be mixed such that the ratio (Cl / Al) of chlorine atoms in the chlorine-based compound precursor to aluminum atoms in the black substance is 3 to 80; 3 to 60; 3 to 50; 3 to 30; 3 to 10; 10 to 80; 20 to 70; 30 to 60; 40 to 90; 50 to 100; 50 to 90; 70 to 99; 20 to 30; 30 to 55; 40 to 50; 45 to 55; 20 to 50; or 60 to 80.

[0069] For example, when the chlorine-based compound precursor is a hydrocarbon compound, the chlorine-based compound precursor can be mixed such that the ratio (Cl / Al) of chlorine atoms in the chlorine-based compound precursor to aluminum atoms in the black substance is 36 to 53.

[0070] When the chlorine-based compound precursor is a polymer compound, the chlorine-based compound precursor can be mixed such that the ratio (Cl / Al) of chlorine atoms in the chlorine-based compound precursor to aluminum atoms in the black substance is 21 to 30; 47 to 53; or 90 to 99.

[0071] This disclosure enables efficient and economical chlorination of aluminum in black matter without excessive use of chlorine-based compound precursors by ensuring that the mixture of black matter and chlorine-based compound precursors meets the aforementioned atomic ratio range. Specifically, if the ratio of chlorine atoms to aluminum atoms (Cl / Al) is less than the lower limit of the aforementioned atomic ratio range, aluminum chlorination in black matter is insufficient, resulting in a significant reduction in aluminum removal efficiency. Furthermore, if the ratio of chlorine atoms to aluminum atoms (Cl / Al) exceeds the upper limit of the aforementioned atomic ratio range, aluminum chlorination in black matter proceeds with high reactivity, but the pressure of the chlorine-based compound may be excessively increased. High-pressure chlorine-based compounds may reduce process safety and cause corrosion inside the reactor. Moreover, excessive use of chlorine-based compound precursors limits economic feasibility.

[0072] The mixture of the black substance and the chlorine-based compound precursor does not contain any components other than the black substance and the chlorine-based compound precursor; however, if the chlorine-based compound precursor is a hydrocarbon compound, it may additionally contain a catalyst to facilitate the reaction between aluminum and chlorine.

[0073] The catalyst can be an aluminum-based catalyst, specifically aluminum chloride (AlCl3). Aluminum chloride (AlCl3) reacts with aluminum (Al) contained in the black substance to produce AlCl and / or AlCl2. The AlCl and / or AlCl2 thus produced can then react rapidly with chlorine-based compounds derived from chlorine-based compound precursors to produce AlCl3. In other words, aluminum chloride (AlCl3) can initiate the oxidation of aluminum (Al) present in the black substance, thereby promoting the chlorination of aluminum.

[0074] For this purpose, based on the total weight of the mixture containing the black substance and the chlorine-based compound precursor, the aluminum-based catalyst can be included in an amount of 0.001 wt% to 5 wt%, specifically, 0.001 wt% to 3 wt%; 0.001 wt% to 2 wt%; 0.001 wt% to 1 wt%; 0.001 wt% to 0.5 wt%; or 0.1 wt% to 0.5 wt%. When the aluminum-based catalyst is included in an amount below the lower limit of the aforementioned concentration range, the effect of promoting aluminum chlorination may be minimal. Furthermore, if the aluminum-based catalyst is included in an amount exceeding the upper limit of the aforementioned concentration range, it may react with the ceramic or glass materials constituting the reactor to produce silicon tetrachloride (SiCl4) and aluminum silicate (Al2SiO5), or corrode the interior of the reactor, thus requiring additional purification processes for the black substance.

[0075] Next, the aluminum removal method of this disclosure includes the step (S2) of heat treating the formed mixture to produce a dealuminized black substance and aluminum chloride gas.

[0076] This step (S2) refers to the process of initiating a reaction between chlorine atoms (Cl) from an activated chlorine-based compound that has evaporated and / or thermally decomposed under high-temperature conditions and aluminum (Al) present in the black substance to form aluminum chloride (AlCl3).

[0077] As an example, when the chlorine-based compound precursor is a hydrocarbon compound, heat treatment causes the chlorine-based compound precursor to evaporate, generating chlorine atoms that react with the activated hydrocarbon compound to form chlorine atoms in the chlorine-based compound, and the activated chlorine atoms in the hydrocarbon compound react with aluminum (Al) present in a solid black substance to form aluminum chloride (AlCl3).

[0078] In another example, when the chlorine-based compound precursor is a polymer compound, heat treatment causes the chlorine-based compound precursor to thermally decompose, producing chlorine (Cl2) and / or hydrogen chloride (HCl) in gaseous form, and the activated chlorine atoms from the produced chlorine (Cl2) and / or hydrogen chloride (HCl) react with aluminum (Al) present in a black substance in solid form to form aluminum chloride (AlCl3).

[0079] Here, the formed aluminum chloride (AlCl3) is in a gaseous state due to the applied heat, allowing for the selective removal of aluminum from the solid black substance, resulting in a dealuminated black substance.

[0080] In this step (S2), the temperature can be controlled to meet a predetermined range during heat treatment, thereby causing the chlorine-based compound precursor to evaporate and / or thermally decompose. Specifically, the heat treatment in this step (S2) can be carried out at a temperature above the temperature at which the chlorine-based compound precursor evaporates or thermally decomposes to produce the chlorine-based compound, but within a temperature range below 300°C. More specifically, the temperature range can be 35°C to 290°C; 35°C to 220°C; 35°C to 190°C; 35°C to 150°C; 50°C to 260°C; 50°C to 180°C; 50°C to 150°C; 50°C to 120°C; 50°C to 90°C; 100°C to 270°C; 100°C to 200°C; 120°C to 200°C; 130°C to 190°C; 150°C to 280°C; 180°C to 280°C; 200°C to 280°C; 240°C to 290°C; or 240°C to 260°C.

[0081] As an example, when the chlorine-based compound precursor is a hydrocarbon compound, the temperature can be controlled above the boiling point (bp) of the hydrocarbon compound during heat treatment, i.e., approximately 35°C to 280°C or approximately 35°C to 200°C, to allow the hydrocarbon compound to evaporate. Here, the boiling points of the hydrocarbon compounds are as follows: carbon tetrachloride (CCl4) approximately 76°C to 77°C; chloroform (CHCl3) approximately 61°C to 62°C; dichloromethane (CH2Cl2) approximately 39°C to 40°C; hexachloroethane (C2Cl6) approximately 184°C to 188°C; tetrachloroethane (C2H2Cl4) approximately 146°C to 147°C; tetrachloroethylene (C2Cl4) approximately 120°C to 122°C; and trichloroethylene (C2HCl3) approximately 87°C to 88°C.

[0082] As another example, when the chlorine-based compound precursor is a polymer compound, the temperature can be adjusted to about 240°C or higher but below 300°C during heat treatment to promote the thermal decomposition of the polymer compound (e.g., polyvinyl chloride), specifically, the temperature can be adjusted to about 250°C to 280°C.

[0083] Furthermore, heat treatment can be carried out in a closed-system reactor (e.g., an autoclave) where heat can be applied to the reactants and the increased internal pressure caused by the applied heat can be maintained. As seen in solvothermal reactions, a closed-system reactor can increase the reactivity of the reactants by maintaining an increased vapor pressure of the reactants or an increased pressure caused by the heat-generated products during heat treatment. In other words, this disclosure can promote the chlorination reaction of aluminum in ferrous materials by maintaining an increased internal pressure in a closed-system reactor due to the chlorine-based compounds generated by heat treatment from chlorine-based compound precursors.

[0084] Therefore, the heat treatment described in this disclosure can be carried out under predetermined pressure conditions. Specifically, the heat treatment can be carried out at pressures greater than 1.0 bar and less than 15 bar, more specifically, 1.1 bar to 15 bar; 1.1 bar to 12 bar; 1.1 bar to 10 bar; 1.1 bar to 7.5 bar; 1.1 bar to 5 bar; 1.5 bar to 7.0 bar; 1.5 bar to 3.5 bar; 2.0 bar to 3.0 bar; 3.0 bar to 9.0 bar; 4.0 bar to 8.0 bar; 5.0 bar to 10 bar; 8.0 bar to 12 bar; or 11 bar to 15 bar.

[0085] During heat treatment, if the internal pressure of the reactor drops below the lower limit of the aforementioned range, the effect of promoting the chlorination reaction of aluminum in the black material is minimal, resulting in a low aluminum removal rate. Furthermore, if the internal pressure of the reactor exceeds the upper limit of the aforementioned range during heat treatment, the reactor may be damaged during the reaction, posing a safety risk and limiting the safety of the process.

[0086] Furthermore, the heat treatment can be carried out for 10 to 50 hours. More specifically, the heat treatment can be carried out for 10 to 40 hours; 10 to 30 hours; 15 to 40 hours; 15 to 30 hours; or 20 to 25 hours. If the heat treatment is carried out for a shorter duration than the lower limit of the aforementioned time range, the provided time is insufficient for the aluminum in the black substance to be converted into aluminum chloride, resulting in a low aluminum removal rate. Furthermore, even if the heat treatment is carried out for a longer duration than the upper limit of the aforementioned time range, it is difficult to achieve improved aluminum removal efficiency or other beneficial effects, thus reducing process efficiency and economic feasibility.

[0087] Furthermore, the heat treatment can be carried out under conditions in which moisture (H2O) or oxygen (O2) is removed from the reaction interior. Specifically, in this step (S2), after the black substance and the chlorine-based compound precursor are introduced into the reactor, a vacuum is created inside the reactor to remove moisture (H2O) or oxygen (O2) present within the reactor. Then, by injecting an inert gas such as helium (He), neon (Ne), nitrogen (N2), or argon (Ar) into the reactor, the internal pressure of the reactor can be controlled to 1 bar before the heat treatment.

[0088] Aluminum chloride (AlCl3) is highly reactive and readily forms aluminum chloride hydrate (AlCl3·6H2O) upon contact with moisture or oxygen in the air. This aluminum chloride hydrate (AlCl3·6H2O) transforms into aluminum oxide (Al2O3) at high temperatures, making it difficult to remove aluminum from black substances. Therefore, this disclosure improves the efficiency of aluminum removal from black substances by minimizing the formation of aluminum oxide (Al2O3) during heat treatment by removing moisture and oxygen present inside the reactor prior to heat treatment.

[0089] The reactors used in this disclosure may be limited by the materials used to construct their interiors. Specifically, the reactors may be constructed of ceramic, glass, or stainless steel materials, and the interiors of the reactors may be coated with fluorine-based resins such as polytetrafluoroethylene (PTFE) for purposes such as heat resistance and chemical resistance.

[0090] Furthermore, the aluminum removal method according to this disclosure may also include the following steps: such as Figure 2 As shown, after the generation of dealuminized black material and aluminum chloride gas (S2), aluminum chloride gas is separated from the dealuminized black material (S3); and the separated aluminum chloride gas is condensed (S4).

[0091] Specifically, the aluminum removal method involves heat-treating a mixture of a black substance and a chlorine-based compound precursor for a predetermined time to produce solid-state dealuminated black substance and gaseous aluminum chloride (S2). Then, while maintaining the heat treatment temperature for 0.5 to 2 hours, a valve on a separate inlet pipe to the reactor can be opened to depressurize the internal pressure of the reactor to approximately 10 °C. -1 The gaseous aluminum chloride produced in the reactor can be separated separately (S3). Here, the predetermined time can be the same as the previous heat treatment time. The separated aluminum chloride is collected and cooled to a temperature below 150°C, preferably to room temperature (18°C to 25°C) for condensation (S4).

[0092] The black substance obtained through the above process can be a dealuminated black substance with a significantly reduced aluminum content because aluminum has been selectively removed. Specifically, the aluminum removal method according to this disclosure can remove aluminum from the black substance with high efficiency, and the aluminum removal efficiency can be 40% or higher. Specifically, the aluminum removal method can achieve aluminum removal efficiencies of 50% or higher, 60% or greater, 70% or greater, 80% or greater, 90% or greater, 50% to 99%, 60% to 95%, 50% to 80%, 55% to 75%, 60% to 70%, 80% to 99%, or 70% to 90%.

[0093] Therefore, the aluminum-removed black matter (i.e., dealuminated black matter) produced according to this disclosure can have a significantly reduced aluminum content in the black matter. Here, the aluminum content in the dealuminated black matter can vary depending on the ratio of aluminum contained in the black matter before dealuminating.

[0094] As an example, a black substance containing 3% to 4% aluminum before aluminum removal may have an aluminum content of 3% or less based on the total weight after undergoing the aluminum removal method according to this disclosure, specifically, 0.1% to 2.5% by weight, 0.1% to 2.0% by weight, 0.1% to 1.7% by weight, 0.1% to 1.5% by weight, 0.1% to 1.3% by weight, 0.5% to 2.4% by weight, 0.5% to 1.9% by weight, 1.5% to 2.8% by weight, or 1.1% to 2.7% by weight.

[0095] The aluminum removal method according to this disclosure, having the aforementioned configuration, selectively removes aluminum (Al) contained in the black material derived from waste batteries by heat-treating it with a chlorine-based compound precursor, thereby enabling the recovery of lithium (Li) from the black material with high purity and recovery rate. Furthermore, the aluminum removal method offers advantages such as ease of process control and high safety.

[0096] The present disclosure will now be described in more detail with reference to embodiments and experimental examples.

[0097] However, the following embodiments and experimental examples are merely illustrative of this disclosure and are not intended to limit the scope of this disclosure.

[0098] Examples 1 to 11 and Comparative Examples 1 to 4. Removal of aluminum from black substances

[0099] The following failed lithium-ion secondary battery cells are to be installed: including LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 A positive electrode with O2 as the positive electrode active material is formed on an aluminum foil; and a negative electrode with a graphite-containing negative electrode active material is formed on a copper foil.

[0100] The prepared lithium secondary battery cells are pulverized to obtain the average particle size (D). 50 The black material ranged in size from 8 μm to 12 μm. Inductively coupled plasma mass spectrometry (ICP-MS) was then performed on the obtained black material to measure the content of the metal components contained in the black material per 1 kg of black material. The results are shown in Table 1 below.

[0101] [Table 1]

[0102]

[0103] As precursors for chlorine-based compounds, the following hydrocarbon compounds were prepared in liquid form: ① carbon tetrachloride (CCl4), ② chloroform (CHCl3), ③ dichloromethane (CH2Cl2), ④ trichloroethylene (C2HCl3), and ⑤ tetrachloroethylene (C2Cl4); a polymer compound in solid form: ⑥ polyvinyl chloride (PVC); and gases: ⑦ hydrogen chloride (HCl) gas and ⑧ chlorine (Cl2) gas. In addition, aluminum chloride (AlCl3 (anhydrous), purity: 98.0%) was prepared as a catalyst.

[0104] In addition, the following are prepared as reactors: ⓐ a pressure vessel made of ceramic material with an internal coating of polytetrafluoroethylene (PTFE); and ⓑ an aluminum crucible that cannot maintain internal pressure during heat treatment.

[0105] The prepared black substance was introduced into a reactor (capacity: 250 mL), and a chlorine-based compound precursor was injected to adjust the ratio of chlorine (Cl) atoms to aluminum (Al) atoms in the black substance (Cl / Al) to the values ​​shown in Table 2. The reactor was then sealed.

[0106] A vacuum is created within a sealed reactor to remove moisture (H2O) and oxygen (O2) present in the reactor, and aluminum chloride (AlCl3) is added to constitute 0.2% by weight of the total mixture. Nitrogen (N2) gas is injected into the reactor to adjust the internal pressure to 1 bar. Here, if the chlorine-based compound precursor is ⑦ hydrogen chloride (HCl) gas or ⑧ chlorine (Cl2) gas, only the black substance is introduced into the reactor, and the moisture and oxygen in the reactor are replaced with hydrogen chloride (HCl) gas or chlorine (Cl2) gas to adjust the internal pressure of the reactor to 1 bar.

[0107] Subsequently, the reactor was heated to the reaction temperature shown in Table 2, and the mixture of the black substance and the chlorine-based compound precursor was heat-treated for 24 hours from the time the reaction temperature was reached.

[0108] After 24 hours, while maintaining the reaction temperature for 1 hour, the reactor pressure was reduced to 10. -1 The gas inside the reactor is collected. The collected gas is cooled to room temperature (18°C to 25°C) to obtain condensate, and the reactor is opened to obtain the black substance after the reaction is complete.

[0109] X-ray diffraction (XRD) and inductively coupled plasma mass spectrometry (ICP-MS) were performed on the collected condensate and black material to determine the residual aluminum components and their content in the condensate and black material. The results are shown in Table 3 below.

[0110] [Table 2]

[0111]

[0112] [Table 3]

[0113]

[0114] As shown in Table 3, the aluminum removal method according to this disclosure is effective in removing aluminum present in black substances.

[0115] Specifically, when a mixture of black matter and chlorine-based compound precursors is subjected to heat treatment at a temperature in which the chlorine-based compound precursors evaporate or thermally decompose to produce chlorine (Cl) compounds, the aluminum (Al) in the black matter is converted to aluminum chloride (AlCl3) and volatilized, resulting in an aluminum removal rate of 50% or greater.

[0116] On the other hand, in Comparative Examples 1 and 2, in which the mixture of black material and chlorine-based compound precursor was heat-treated at a temperature lower than the temperature at which the chlorine-based compound precursor evaporated or underwent thermal decomposition to produce chlorine (Cl) compound, and in Comparative Examples 3 and 4, in which hydrogen chloride gas or chlorine gas was used as chlorine-based compound precursor, the chlorination of aluminum in the black material was insufficient, so that aluminum was almost completely not removed.

[0117] Based on these results, it can be concluded that the aluminum removal method according to this disclosure can selectively remove aluminum (Al) from black matter derived from waste batteries by heat-treating the black matter with a chlorine-based compound precursor under specific temperature conditions, thereby allowing lithium (Li) to be obtained with high purity and recovery rate.

[0118] The above description has been provided with reference to preferred embodiments of the present disclosure; however, those skilled in the art will understand that various modifications and changes can be made to the present disclosure within the technical field as described in the appended claims without departing from the scope of the present disclosure.

[0119] Therefore, the technical scope of this disclosure is not limited to the specific embodiments described in this specification, but should be determined by the scope of the claims.

Claims

1. A method for removing aluminum from black material derived from failed batteries, comprising: A mixture containing a black substance and a chlorine-based compound precursor is formed (S1); as well as The resulting mixture is heat-treated to produce a black substance that has undergone dealuminization and aluminum chloride gas (S2). The heat treatment is carried out at a temperature above the temperature at which the chlorine-based compound precursor evaporates or thermally decomposes to produce the chlorine compound, but below 300°C.

2. The method for removing aluminum according to claim 1, wherein the chlorine-based compound precursor comprises at least one of the following: C atoms in which at least one hydrogen atom is replaced by a chlorine atom. 1-6 Hydrocarbon compounds and polymeric compounds in which at least one hydrogen atom is replaced by a chlorine atom.

3. The method for removing aluminum according to claim 2, wherein the hydrocarbon compound comprises one or more of carbon tetrachloride (CCl4), chloroform (CHCl3), dichloromethane (CH2Cl2), hexachloroethane (C2Cl6), tetrachloroethane (C2H2Cl4), tetrachloroethylene (C2Cl4), and trichloroethylene (C2HCl3).

4. The method for removing aluminum according to claim 2, wherein the polymer compound comprises polyvinyl chloride (PVC).

5. The method for removing aluminum according to claim 1, wherein the heat treatment is carried out in a reactor capable of maintaining the increased internal pressure during the heat treatment.

6. The method for removing aluminum according to claim 1, wherein the heat treatment is carried out at a pressure greater than 1 bar and 15 bar or less.

7. The method for removing aluminum according to claim 1, wherein the mixture further comprises an aluminum-based catalyst, said aluminum-based catalyst comprising aluminum chloride (AlCl3).

8. The method for removing aluminum according to claim 1, wherein the average particle size of the black substance is from 0.5 μm to 1,000 μm.

9. The method for removing aluminum according to claim 1, wherein the black substance contains aluminum in an amount greater than 0.5% by weight and less than 5% by weight relative to the total weight.

10. The method for removing aluminum according to claim 1, wherein... The chlorine-based compound precursor is mixed with the black substance such that the ratio (Cl / Al) of chlorine atoms in the chlorine-based compound precursor to aluminum atoms in the black substance is 3 to 100.

11. The method for removing aluminum according to claim 1, wherein the heat treatment of the black substance and the chlorine-based compound precursor is performed for 10 to 50 hours.

12. The method for removing aluminum according to claim 1, wherein the method for removing aluminum further comprises: After the production of black dealuminated material and aluminum chloride gas (S2), Aluminum chloride gas (S3) is separated from the dealuminized black substance; and The separated aluminum chloride gas is condensed (S4).

13. The method for removing aluminum according to claim 1, wherein the dealuminized black substance has an aluminum content of 3% by weight or less relative to the total weight.

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