Method for removing aluminum from black mass derived from waste batteries

Abstract

The present invention relates to a method for removing aluminum (Al) from a black mass derived from deactivated batteries. The aluminum removal method enables the selective removal of only aluminum by thermally treating a black mass, derived from waste batteries, together with a chlorine compound precursor, so that lithium (Li) can be obtained with high purity and recovery rate. Furthermore, the aluminum removal method facilitates process control and has high safety. Furthermore, the aluminum removal method facilitates process control and has high safety.

Description

A method for removing aluminum from black mass derived from used batteries.

[0001] The present invention relates to a method for selectively removing aluminum from black mass derived from a deactivated lithium secondary battery and / or anode scrap, etc.

[0002] This application claims the benefit of priority to Republic of Korea Patent Application No. 10-2023-0115629, filed August 31, 2023, and Republic of Korea Patent Application No. 10-2024-0094796, filed July 18, 2024, the entire contents of which are incorporated herein by reference.

[0003]

[0004] Lithium batteries, commonly used in automobiles, consist of a cathode and anode separated by a separator, with an electrolyte filled between them. The most crucial component of these lithium secondary batteries is lithium, the main component of the cathode. Lithium is typically manufactured from lithium-containing ore, and is traded at a relatively high price due to the costs of the manufacturing process and the raw material itself. Therefore, to lower the manufacturing cost of lithium secondary batteries, research is being conducted not only on the performance of lithium secondary batteries themselves, but also on methods to recover and reuse lithium components from used lithium batteries.

[0005] To recover lithium contained in the cathode, the cathode must be disassembled and released from a deactivated lithium battery. However, due to the organic substances contained in the organic binder (e.g., NMP, PVDF), the lithium contained in the cathode is not easily dissolved in various organic solvents, does not easily detach even with ultrasound, and is difficult to filter.

[0006] Accordingly, a wet process has been applied to extract lithium from cathode active materials, which involves dissolving crushed waste battery material (e.g., black mass) containing cathode active materials in an acidic solvent to separate the individual metals. More specifically, the wet process involves discharging the waste battery, then crushing the waste battery itself or the cathode separated from the waste battery. Subsequently, a roasting process is performed on the crushed pieces to vaporize / remove components other than the metal components, and the residue is immersed in an acidic solvent to extract the lithium, thereby recovering it.

[0007] However, since the above wet process uses an acidic solvent, it requires a lot of cost to dispose of the waste acidic solvent generated after the process is completed, and there is a problem of environmental pollution due to byproducts. In addition, the above method easily forms slag by agglomerating the lithium (Li) component contained in the cathode active material and the aluminum (Al) component of the current collector during the roasting process before acid treatment. It is very difficult to selectively separate the lithium (Li) component and other components from the slag formed in this way due to the aluminum (Al) component contained therein, and even if separated, the recovery rate is significantly reduced due to impurities.

[0008]

[0009] [Prior Art Literature]

[0010] Republic of Korea Patent Publication No. 10-2019-0082167

[0011]

[0012] Accordingly, the purpose of the present invention is to provide a technology capable of obtaining lithium (Li) with high purity and recovery rate by selectively removing only aluminum (Al) from black mass when recovering lithium from a deactivated waste battery.

[0013]

[0014] To solve the above-mentioned problem,

[0015] In one embodiment of the present invention,

[0016] A method for removing aluminum from black mass derived from a deactivated battery,

[0017] A step (S1) of forming a mixture containing black mass and a chlorine compound precursor; and

[0018] A step (S2) of heat treating the formed mixture to produce dealuminate black mass and aluminum chloride gas,

[0019] The above heat treatment provides a method for removing aluminum, wherein the heat treatment is performed at a temperature higher than or equal to the temperature at which the chlorine compound precursor is vaporized or thermally decomposed to generate a chlorine compound; and less than or equal to 300°C.

[0020] At this time, the chlorine compound precursor is C in which at least one hydrogen is replaced by a chloro group. 1-6 It may include at least one of a hydrocarbon compound and a polymer compound in which at least one hydrogen is substituted with a chloro group.

[0021] The above hydrocarbon compound may include at least one of tetrachloromethane (CCl4), chloroform (CHCl3), dichloromethane (CH2Cl2), hexachloroethane (C2Cl6), tetrachloroethane (C2H2Cl4), tetrachloroethylene (C2Cl4), and trichloroethylene (C2HCl3).

[0022] Additionally, the polymer compound may include polyvinyl chloride (PVC).

[0023] Additionally, the heat treatment can be performed in a reactor capable of maintaining an internal pressure that increases during the heat treatment.

[0024] Additionally, the heat treatment can be performed at a pressure of more than 1 bar and less than or equal to 15 bar.

[0025] Additionally, the mixture may further comprise an aluminum-based catalyst including aluminum chloride (AlCl3).

[0026] In addition, the average particle diameter of the black mass may be 0.5 ㎛ to 1,000 ㎛.

[0027] Additionally, the black mass may contain aluminum in an amount of more than 0.1 wt% and less than 5 wt% based on the total weight.

[0028] In addition, the chlorine compound precursor may be mixed with the black mass so that the ratio of chlorine atoms contained in the chlorine compound precursor to aluminum atoms contained in the black mass (Cl / Al) is 3 to 100, and the heat treatment of the black mass and the chlorine compound precursor may be performed for 10 to 50 hours.

[0029] Meanwhile, the above aluminum removal method,

[0030] After the step (S2) of generating dealuminate black mass and aluminum chloride gas,

[0031] A step (S3) of separating aluminum chloride gas from the de-aluminated black mass; and

[0032] It may further include a step (S4) of condensing the separated aluminum chloride gas.

[0033] Furthermore, the above-mentioned dealumination black mass may have an aluminum element content of 3 wt% or less based on the total weight.

[0034]

[0035] The aluminum removal method according to the present invention selectively removes only aluminum (Al) by heat-treating black mass derived from spent batteries with a chlorine compound precursor under predetermined temperature conditions, thereby obtaining lithium (Li) with high purity and recovery rate. Furthermore, the aluminum removal method has the advantages of easy process control and high safety.

[0036]

[0037] Figures 1 and 2 are process diagrams schematically showing an aluminum removal method according to the present invention.

[0038]

[0039] The present invention can be modified in various ways and has many embodiments, and specific embodiments will be described in detail in the detailed description.

[0040] However, this is not intended to limit the present invention to a specific embodiment, but should be understood to include all modifications, equivalents, or substitutes included in the technical scope of the present invention.

[0041] In the present invention, it should be understood that terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0042] Additionally, in the present invention, when a part such as a layer, film, region, or plate is described as being "on" another part, this includes not only cases where it is "directly above" the other part, but also cases where there is another part in between. Conversely, when a part such as a layer, film, region, or plate is described as being "under" another part, this includes not only cases where it is "directly below" the other part, but also cases where there is another part in between. Furthermore, in the present application, "on" may include cases where it is placed below as well as above.

[0043] In addition, in the present invention, "average particle diameter (D 50)" means the particle diameter at which the integrated value is 50% in the particle diameter distribution of the particles, and is also called the median diameter. The above average particle diameter can be measured by a method commonly applied in the art. For example, the above average particle diameter can be measured using an analysis device that uses a laser diffraction scattering particle size distribution measurement method according to ISO 13320.

[0044]

[0045] Hereinafter, the present invention will be described in more detail.

[0046]

[0047] In one embodiment of the present invention,

[0048] A method for removing aluminum from black mass derived from a deactivated battery,

[0049] A step (S1) of forming a mixture containing black mass and a chlorine compound precursor; and

[0050] A step (S2) of heat treating the formed mixture to produce dealuminate black mass and aluminum chloride gas,

[0051] The above heat treatment provides a method for removing aluminum, wherein the heat treatment is performed at a temperature higher than or equal to the temperature at which the chlorine compound precursor is vaporized or thermally decomposed to generate the chlorine compound; and less than or equal to 300°C.

[0052]

[0053] The present invention relates to a method for selectively removing aluminum derived from a positive electrode collector of a lithium waste battery when recovering lithium from a deactivated lithium waste battery.

[0054] The above aluminum removal method can be performed by heat-treating a mixture of a lithium-containing material derived from a deactivated waste battery and a chlorine compound precursor. Specifically, the aluminum removal method can be performed by performing a step (S1) of forming a mixture comprising a black mass derived from a deactivated battery and a chlorine compound precursor; and a step (S2) of heat-treating the formed mixture to produce dealuminate black mass and aluminum chloride gas. The aluminum removal method heat-treats black mass derived from a waste battery together with a chlorine compound precursor to chlorinate aluminum contained in the black mass. The aluminum chloride (AlCl3) produced at this time undergoes a phase change to a gas at about 180°C, and thus can be volatilized under high-temperature conditions.

[0055] Therefore, the aluminum removal method according to the present invention can selectively remove aluminum within black mass by converting it into aluminum chloride (AlCl3) and then volatilizing it. The dealuminate black mass thus produced has a significantly reduced aluminum (Al) content, thereby providing lithium (Li) with high purity and recovery rate in a lithium recovery process.

[0056]

[0057] Figures 1 and 2 are process diagrams schematically illustrating the process steps of an aluminum removal method according to the present invention. Hereinafter, each step will be described in more detail with reference to Figures 1 and 2.

[0058] First, the aluminum removal method of the present invention includes a step (S1) of forming a mixture of black mass and a chlorine compound precursor. This step (S1) refers to a process of mixing black mass derived from a deactivated battery with a chlorine compound precursor capable of providing a chlorine compound to aluminum (Al) contained in the black mass.

[0059] Here, the black mass may be particles obtained by discharging and crushing a deactivated battery, i.e., a waste battery, and in some cases, may include black powder obtained by separating and crushing only the positive electrode from a waste battery.

[0060] The above black mass may include, in addition to lithium, 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 mass may be derived from a positive electrode having a structure in which a positive electrode active layer including the positive electrode active material is formed on an aluminum thin plate, which is a positive electrode current collector. Accordingly, the black mass may include, in addition to lithium (Li), valuable metals such as nickel (Ni), cobalt (Co), manganese (Mn), and iron (Fe), and aluminum (Al) in a predetermined content range.

[0061] Here, the positive electrode active 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 0.1 O2, LiNi 0.7 Mn 1.3 O4, LiNi 0.5 Mn 1.5 O4, LiNi 0.3 Mn 1.7 Lithium nickel composite oxides such as O4, LiFePO4, LiFe 0.8 Mn 0.2 PO4, LiFe 0.5Mn 0.5 Lithium iron phosphate such as PO4 may be included alone or in combination of two or more, but is not limited thereto.

[0062] The black mass may contain 1 to 10 wt% of lithium and 15 to 40 wt% of valuable metals (i.e., Ni, Co, Mn) based on the total weight. In addition, the black mass may contain more than 0.5 wt% of aluminum based on the total weight, and specifically, may contain aluminum at 1 to 5 wt%; 0.5 to 3 wt%; 1 to 3 wt%; 2 to 4 wt%; 2.5 to 5 wt%; or 2.5 to 4.5 wt%. The remaining portion may be comprised of an anode active material such as graphite or silicon constituting the anode of a lithium secondary battery, a metal such as copper constituting the anode current collector, and an organic material constituting a separator.

[0063] The above black mass can be adjusted so that the average particle diameter satisfies a predetermined range. Specifically, the black mass has an average particle diameter (D) of 0.5 ㎛ to 1,000 ㎛. 50 ), and more specifically, the average particle diameter (D) of 0.5 ㎛ to 750 ㎛; 0.5 ㎛ to 500 ㎛; 0.5 ㎛ to 250 ㎛; 0.5 ㎛ to 100 ㎛; 0.5 ㎛ to 50 ㎛; 0.5 ㎛ to 20 ㎛; 0.5 ㎛ to 10 ㎛; 1 ㎛ to 15 ㎛; 5 ㎛ to 15 ㎛; 10 ㎛ to 200 ㎛; 50 ㎛ to 500 ㎛; 100 ㎛ to 300 ㎛; 400 ㎛ to 700 ㎛; 500 ㎛ to 900 ㎛; 50 ㎛ to 150 ㎛; or 5 ㎛ to 80 ㎛ 50 ) can have.

[0064] If the average particle size of the black mass is smaller than the lower limit of the above-described range, coagulation may occur between the black mass particles, which may hinder the smooth chlorination reaction of the aluminum present within the coagulated black mass. In addition, if the average particle size of the black mass is larger than the upper limit of the above-described range, chlorine may have difficulty penetrating into the black mass particles, thereby reducing the aluminum removal efficiency.

[0065] Meanwhile, the chlorine-based compound precursors refer to compounds capable of providing chlorine compounds under high-temperature conditions. The chlorine compounds may be hydrocarbon compounds in which chlorine atoms are activated by vaporization and increased internal molecular energy, or may include chlorine (Cl2) gas and / or hydrogen chloride (HCl). The chlorine compound precursors may be substances that are in a liquid or solid state at room temperature (e.g., 18 to 25°C) in terms of safety and processability due to chlorine compounds generated during reaction with black mass.

[0066] Specifically, the chlorine compound precursor is C in which at least one hydrogen is replaced by a chloro group. 1-6 A hydrocarbon compound; and at least one polymer compound in which at least one hydrogen is substituted with a chloro group.

[0067] The hydrocarbon compound may be a hydrocarbon compound having 1 to 6 carbon atoms, i.e., a compound in which at least one hydrogen atom is replaced with a chloro group (-Cl) in a compound such as methane (carbon number: 1), ethane (carbon number: 2), or propane (carbon number: 3). For example, the hydrocarbon compound may include at least one of tetrachloromethane (CCl4), chloroform (CHCl3), dichloromethane (CH2Cl2), hexachloroethane (C2Cl6), tetrachloroethane (C2H2Cl4), tetrachloroethylene (C2Cl4), and trichloroethylene (C2HCl3). The hydrocarbon compound may be in a liquid state at room temperature (about 20±5°C) and atmospheric pressure (about 1 atm).

[0068] The above polymer compound refers to a high molecular weight compound having a molecular weight of 1,000 g / mol or more and including a hydrocarbon chain, wherein at least one hydrogen atom in the hydrocarbon chain is replaced with a chloro group. For example, the polymer compound may include polyvinyl chloride (PVC). The polymer compound may be in a solid state at room temperature (about 20±5°C) and atmospheric pressure (about 1 atm).

[0069] In addition, materials that are considered to be applicable as chlorine compound precursors include gases such as chlorine (Cl2) gas and hydrogen chloride (HCl) gas; inorganic solvents such as dilute hydrochloric acid; and metal salts such as lithium chloride (LiCl), sodium chloride (NaCl), potassium chloride (KCl), and calcium chloride (CaCl2).

[0070] However, gases such as chlorine gas (Cl2) and hydrogen chloride (HCl) are not highly reactive with aluminum in black mass at low temperatures. Furthermore, these gases are difficult to control during processing and are highly toxic to the human body, making them unsafe and therefore unsuitable as chlorine compound precursors.

[0071] Additionally, inorganic solvents such as dilute hydrochloric acid contain water (H2O). The water reacts preemptively with aluminum (Al) to form aluminum oxide (Al2O3) before the chlorine (Cl) of the chlorine compound reacts with the aluminum (Al) present in the black mass. Since aluminum oxide changes into a gas at approximately 2977°C, it is difficult to remove aluminum through volatilization, and a separate, additional purification process is required to remove it.

[0072] In addition, since metal salts containing chlorine undergo a phase change to a gaseous state at temperatures above approximately 600°C to provide chlorine, there are limitations in that high energy and cost are required to supply chlorine from a chlorine compound precursor during the process. Furthermore, the metal salts have low reactivity with aluminum (Al) in the black mass and the provided chlorine (Cl) compound, making it difficult to form aluminum chloride (AlCl3).

[0073] On the other hand, hydrocarbon compounds and / or polymer compounds having a chemical structure in which chlorine is substituted in a chain-shaped hydrocarbon group are easy to control during the process, and the substance itself has low toxicity to the human body, so it is highly safe. In addition, the hydrocarbon compound undergoes a phase change into a gas at a temperature of 200°C or lower, easily providing chlorine element with increased intramolecular reactivity to the black mass, and the polymer compound can be thermally decomposed at about 240 to 270°C to provide chlorine (Cl2) and / or hydrogen chloride (HCl) in a gaseous form. Therefore, the hydrocarbon compound and / or polymer compound has the excellent characteristic of providing vaporized hydrocarbon compounds that are chlorine compounds or gaseous chlorine (Cl2) and / or hydrogen chloride (HCl). The chlorine compound provided in this way has the advantage of being highly reactive with aluminum (Al) in the black mass, thereby rapidly generating aluminum chloride (AlCl3), and thus has an excellent effect in removing aluminum (Al) in the black mass.

[0074] The above chlorine compound precursor may be tetrachloromethane (CCl4). Tetrachloromethane (CCl4) has a very advantageous advantage in the chlorination reaction of aluminum because the Gibbs free energy of aluminum chloride (AlCl3) when reacted with aluminum and the Gibbs free energy of converting aluminum oxide (Al2O3), which may be generated as a byproduct, into aluminum chloride (AlCl3) are significantly lower and negative.

[0075] Additionally, the chlorine compound precursor may be polyvinyl chloride (PVC). Polyvinyl chloride (PVC) is characterized by high human safety and process safety. Furthermore, polyvinyl chloride (PVC) is solid at room temperature, making it easy to store and manage the material. Furthermore, polyvinyl chloride (PVC) can quantitatively produce hydrogen chloride (HCl) in gaseous form through pyrolysis, making process control very easy.

[0076] In addition, in this step (S1), the black mass and the chlorine compound precursor may be mixed so that the aluminum (Al) atoms contained in the black mass and the chlorine (Cl) atoms contained in the chlorine compound precursor have a certain atomic ratio. Specifically, aluminum chloride (AlCl3) has a structure in which three chlorine atoms are bonded to one aluminum atom. Therefore, the chlorine compound precursor may be mixed so that the ratio of chlorine atoms to aluminum atoms (Cl / Al) has a value of 3 or more, and more specifically, may be mixed so that it is 3 to 100. For example, the chlorine compound precursor may be mixed so that the ratio of chlorine atoms contained in the chlorine compound precursor to aluminum atoms contained in the black mass (Cl / Al) 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; It can be mixed to be 70 to 99; 20 to 30; 30 to 55; 40 to 50; 45 to 55; 20 to 50; or 60 to 80.

[0077] For example, when the chlorine compound precursor is a hydrocarbon compound, the chlorine compound precursor may be mixed so that the ratio of chlorine atoms contained in the chlorine compound precursor to aluminum atoms contained in the black mass (Cl / Al) is 36 to 53.

[0078] When the above chlorine compound precursor is a polymer compound, the chlorine compound precursor may be mixed so that the ratio of chlorine atoms contained in the chlorine compound precursor to aluminum atoms contained in the black mass (Cl / Al) is 21 to 30; 47 to 53; or 90 to 99.

[0079] The present invention can economically and efficiently perform chlorination of aluminum in black mass without excessive use of chlorine compound precursor by satisfying the above-described atomic ratio range when mixing black mass and chlorine compound precursor. Specifically, if the ratio of chlorine atoms to aluminum atoms (Cl / Al) is lower than the lower limit of the above-described atomic ratio range, chlorination of aluminum in black mass is not sufficiently performed, which causes a significant reduction in aluminum removal efficiency. In addition, if the ratio of chlorine atoms to aluminum atoms (Cl / Al) is higher than the upper limit of the above-described atomic ratio range, chlorination of aluminum in black mass proceeds with high reactivity, but the pressure of the chlorine compound may increase excessively. High pressure of chlorine compound can reduce process safety and cause corrosion inside the reactor. In addition, there is a limitation that economic feasibility is reduced due to the excessive use of chlorine compound precursor.

[0080] The mixture of the above black mass and the chlorine compound precursor does not contain any components other than the black mass and the chlorine compound precursor, but if the chlorine compound precursor is a hydrocarbon compound, it may further contain a catalyst for promoting the reaction between aluminum and chlorine.

[0081] The catalyst may be an aluminum-based catalyst, and specifically, may be aluminum chloride (AlCl3). The aluminum chloride (AlCl3) may react with aluminum (Al) contained in the black mass to produce AlCl and / or AlCl2. The AlCl and / or AlCl2 thus produced may rapidly react with a chlorine compound produced from a chlorine compound precursor to produce AlCl3. That is, the aluminum chloride (AlCl3) may induce oxidation of aluminum (Al) present in the black mass, thereby promoting chlorination of aluminum.

[0082] To this end, the aluminum-based catalyst may be included in an amount of 0.001 to 5 wt% based on the total weight of the mixture including the black mass and the chlorine compound precursor, specifically, 0.001 to 3 wt%; 0.001 to 2 wt%; 0.001 to 1 wt%; 0.001 to 0.5 wt%; or 0.1 to 0.5 wt%. If the aluminum-based catalyst is included in an amount less than the lower limit of the above-described content range, the effect of promoting the chlorination of aluminum may be minimal. In addition, if the aluminum-based catalyst is included in an amount greater than the upper limit of the above-described content range, it may react with a ceramic material or glass material constituting the reactor to generate silicon tetrachloride (SiCl4) and aluminum silicate (Al2SiO5) or corrode the inside of the reactor, so that an additional process for purifying the black mass may be required.

[0083]

[0084] Next, the aluminum removal method of the present invention includes a step (S2) of heat treating the formed mixture to generate dealuminate black mass and aluminum chloride gas.

[0085] This step (S2) refers to a process of forming aluminum chloride (AlCl3) by inducing a reaction between chlorine atoms (Cl) of an activated chlorine compound and aluminum (Al) present in black mass through vaporization and / or thermal decomposition of a chlorine compound precursor under high temperature conditions.

[0086] As an example, when the chlorine compound precursor is a hydrocarbon compound, the chlorine compound precursor is vaporized by heat treatment to generate a hydrocarbon compound in which chlorine atoms are activated as a chlorine compound, and the activated chlorine atoms of the hydrocarbon compound react with aluminum (Al) present in a solid state in the black mass to form aluminum chloride (AlCl3).

[0087] As another example, when the chlorine compound precursor is a polymer compound, the chlorine compound precursor is thermally decomposed by heat treatment to generate chlorine compounds such as chlorine (Cl2) and / or hydrogen chloride (HCl) in a gaseous form, and the activated chlorine atoms of the generated chlorine (Cl2) and / or hydrogen chloride (HCl) react with aluminum (Al) present in a solid state in the black mass to form aluminum chloride (AlCl3).

[0088] At this time, the formed aluminum chloride (AlCl3) is in a gaseous state due to the applied heat, so a dealuminate black mass in which aluminum is selectively removed from the solid black mass can be obtained.

[0089] In this step (S2), the temperature can be controlled to satisfy a predetermined range during the heat treatment for vaporization and / or thermal decomposition of the chlorine compound precursor. Specifically, the heat treatment in this step (S2) can be performed at a temperature range higher than the temperature at which the chlorine compound precursor is vaporized or thermally decomposed to generate a chlorine compound; and lower than 300°C, and more specifically, 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; It can be performed at a temperature of 180°C to 280°C; 200°C to 280°C; 240°C to 290°C or 240°C to 260°C.

[0090] As an example, the temperature during the heat treatment may be controlled to a temperature higher than the boiling point (bp) of the hydrocarbon compound when the chlorine compound precursor is a hydrocarbon compound, i.e., a temperature of about 35°C to 280°C or about 35°C to 200°C, for vaporization of the hydrocarbon compound. Here, the boiling points of the hydrocarbon compounds are as follows: Tetrachloromethane (CCl4) about 76 to 77°C Chloroform (CHCl3) about 61 to 62°C Dichloromethane (CH2Cl2) about 39 to 40°C Hexachloroethane (C2Cl6) about 184 to 188°C Tetrachloroethane (C2H2Cl4) about 146 to 147°C Tetrachloroethylene (C2Cl4) about 120 to 122°C Trichloroethylene (C2HCl3) about 87 to 88°C.

[0091] As another example, when the chlorine compound precursor is a polymer compound (e.g., polyvinyl chloride), the temperature during the heat treatment may be controlled to a temperature of about 240°C or higher and less than 300°C for thermal decomposition of the polymer compound, and specifically, may be controlled to a temperature of about 250°C to 280°C.

[0092] In addition, the heat treatment can be performed in a closed system reactor, such as an autoclave, which can apply heat to the reactants while maintaining the internal pressure increased by the applied heat. A closed system reactor can increase the reactivity of the reactants by maintaining the vapor pressure of the reactants increased through phase change during the heat treatment, such as a solventhermal reaction, or the pressure increased by the products generated by the heat. That is, the present invention can further promote the chlorination reaction of aluminum in the black mass by performing the heat treatment in a closed system reactor, thereby maintaining the internal pressure increased by the chlorine compound generated from the chlorine compound precursor, which is a reactant.

[0093] Accordingly, the heat treatment of the present invention can be performed under predetermined pressure conditions. Specifically, the heat treatment can be performed at a pressure of more than 1.0 bar and less than or equal to 15 bar, and 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; It can be performed at a pressure of 8.0 bar to 12 bar; or 11 bar to 15 bar.

[0094] During heat treatment, if the internal pressure of the reactor falls below the lower limit of the above-mentioned range, the effect of promoting the chlorination reaction of aluminum within the black mass may be minimal, resulting in a low aluminum removal rate. Furthermore, if the internal pressure of the reactor exceeds the upper limit of the above-mentioned range during heat treatment, the reactor in which the reaction is performed may be damaged, thus limiting process safety.

[0095] In addition, the heat treatment may be performed for 10 to 50 hours. More specifically, the heat treatment may be performed 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 performed for a time shorter than the lower limit of the above-described time range, there is a problem in that the aluminum removal rate is low because sufficient time is not provided for the aluminum in the black mass to be converted into aluminum chloride. In addition, even if the heat treatment is performed for a time longer than the upper limit of the above-described time range, it is difficult to obtain an effect such as further improving the aluminum removal rate, so the processability and economy may be low.

[0096] Furthermore, the heat treatment can be performed under conditions in which moisture (H2O) or oxygen (O2) is excluded from the inside of the reactor. Specifically, in this step (S2), after injecting black mass and a chlorine compound precursor into the reactor, a vacuum state is formed inside the reactor to remove moisture (H2O) or oxygen (O2) present inside the reactor. Then, an inert gas such as helium (He), neon (Ne), nitrogen (N2), or argon (Ar) is injected into the reactor to control the pressure inside the reactor to 1 bar before the heat treatment.

[0097] Aluminum chloride (AlCl3) is highly reactive and easily forms aluminum chloride hydrate (AlCl3·6H2O) when it comes into contact with moisture or oxygen in the air. Since aluminum chloride hydrate (AlCl3·6H2O) is converted to aluminum oxide (Al2O3) at high temperatures, it becomes difficult to remove aluminum within black mass. Therefore, the present invention can minimize the formation of aluminum oxide (Al2O3) during heat treatment by removing moisture and oxygen present inside the reactor prior to heat treatment, thereby further improving the aluminum removal rate within black mass.

[0098] The reactor used in the present invention may have limitations on the materials used to construct its interior. Specifically, the reactor may be composed of ceramic, glass, or stainless steel, and the interior of the reactor may be coated with a fluorine-based resin such as polytetrafluoroethylene (PTFE) for purposes such as heat resistance and chemical resistance.

[0099]

[0100] Meanwhile, the aluminum removal method according to the present invention may further include a step (S3) of separating aluminum chloride gas from the dealuminate black mass after the step (S2) of generating dealuminate black mass and aluminum chloride gas as shown in FIG. 2; and a step (S4) of condensing the separated aluminum chloride gas.

[0101] Specifically, the above aluminum removal method heat-treats a mixture of black mass and a chlorine compound precursor for a preset time to produce solid-state dealuminate black mass and gaseous aluminum chloride (S2), and then maintains the heat treatment temperature for 0.5 to 2 hours, and opens the valve of a pipe separately introduced into the reactor to cool the inside of the reactor to about 10 -1 torr. The gaseous aluminum chloride generated inside the reactor according to the above-mentioned depressurization can be separated separately (S3). Here, the preset time may be the same as the time for performing the heat treatment previously. The separated aluminum chloride can be collected and then cooled to a temperature below 150°C, preferably to room temperature (18-25°C), and condensed (S4).

[0102] The black mass obtained through the above process may be a dealuminate black mass in which aluminum is selectively removed and the aluminum content is significantly lower. Specifically, the aluminum removal method according to the present invention can remove aluminum in the black mass with high efficiency, and the aluminum removal efficiency may be 40% or more. Specifically, the aluminum removal method may have an aluminum removal efficiency of 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 50-99%, 60-95%, 50-80%, 55-75%, 60-70%, 80-99%, or 70-90%.

[0103] Accordingly, the black mass from which aluminum has been removed according to the present invention, i.e., the dealuminate black mass, may have a significantly lower aluminum content within the black mass. Here, the aluminum content within the dealuminate black mass may differ in the proportion of the remaining aluminum content depending on the proportion of the aluminum content contained in the black mass prior to dealumination.

[0104] As an example, black mass having an aluminum content of 3 to 4 wt% before aluminum removal is performed may have an aluminum content of 3 wt% or less based on the total weight after performing the aluminum removal method according to the present invention, and specifically, may have an aluminum content of 0.1 to 2.5 wt%, 0.1 to 2.0 wt%, 0.1 to 1.7 wt%, 0.1 to 1.5 wt%, 0.1 to 1.3 wt%, 0.5 to 2.4 wt%, 0.5 to 1.9 wt%, 1.5 to 2.8 wt%, or 1.1 to 2.7 wt% based on the total weight of the black mass.

[0105]

[0106] The aluminum removal method according to the present invention, having the above-described configuration, selectively removes only aluminum (Al) contained in black mass derived from spent batteries by heat-treating the black mass together with a chlorine compound precursor, thereby obtaining lithium (Li) from the black mass with high purity and recovery rate. In addition, the aluminum removal method has the advantages of easy process control and high safety.

[0107]

[0108] Hereinafter, the present invention will be described in more detail through examples and experimental examples.

[0109] However, the following examples and experimental examples are only illustrative of the present invention, and the content of the present invention is not limited to the following examples and experimental examples.

[0110]

[0111] Examples 1 to 11 and Comparative Examples 1 to 4. Removal of aluminum in black mass

[0112] LiNi as a cathode active material 1 / 3 Co 1 / 3 Mn 1 / 3 An inactive lithium secondary battery cell was prepared, comprising a positive electrode having a structure in which a positive active layer including O2 is provided on an aluminum foil; and a negative electrode having a structure in which a negative active layer including graphite as an negative active material is provided on a copper foil.

[0113] The prepared lithium secondary battery cell was crushed to obtain an average particle size (D 50 ) was obtained as a black mass having a particle size of 8 to 12 μm. At this time, inductively coupled plasma mass spectrometry (ICP-MS) was performed on the obtained black mass to measure the content of metal components contained in the black mass per 1 kg of black mass. The results are shown in Table 1 below.

[0114] Metal composition content: Li36.7 gNi93.9 gCo84.4 gMn88.2 gAl37.7 gCu20.2 gMg0.63 gCa0.21 gZn0.35 gFe2.5 gNa0.74 g

[0115]

[0116]

[0117] As chlorine compound precursors, liquid hydrocarbon compounds of ① tetrachloromethane (CCl4), ② chloroform (CHCl3), ③ dichloromethane (CH2Cl2), ④ trichloroethylene (C2HCl3), and ⑤ tetrachloroethylene (C2Cl4); solid polymer compounds of ⑥ polyvinyl chloride (PVC); and gases of ⑦ hydrogen chloride (HCl) gas and ⑧ chlorine (Cl2) gas were prepared, respectively. In addition, aluminum chloride (AlCl3 (anhydous), purity: 98.0%) was prepared as a catalyst.

[0118] In addition, as reactors, ⓐ an autoclave made of ceramic material coated on the inside with polytetrafluoroethylene (PTFE) and ⓑ an aluminum crucible that does not maintain the internal pressure that increases during heat treatment were prepared.

[0119] The previously prepared black mass was introduced into a reactor (capacity: 250 ml), and the chlorine compound precursor was injected so that the ratio of chlorine (Cl) atoms of the chlorine compound precursor to aluminum (Al) atoms contained in the black mass (Cl / Al) was adjusted as shown in Table 2 below, and then the reactor was sealed.

[0120] A vacuum was formed inside a sealed reactor to remove moisture (H2O) and oxygen (O2) present inside the reactor, and aluminum chloride (AlCl3), a catalyst, was introduced so as to be 0.2 wt% of the total mixture. Nitrogen (N2) gas was injected into the reactor to adjust the internal pressure of the reactor to 1 bar. Here, when the chlorine compound precursor is ⑦ hydrogen chloride (HCl) gas or ⑧ chlorine (Cl2) gas, only black mass was introduced into the reactor, and moisture and oxygen inside the reactor were replaced with hydrogen chloride (HCl) gas or chlorine (Cl2) gas to adjust the internal pressure of the reactor to 1 bar.

[0121] Thereafter, the temperature inside the reactor was heated to reach the reaction temperature shown in Table 2, and the mixture of black mass and chlorine compound precursor was heat-treated for 24 hours based on the time at which the reaction temperature was reached.

[0122] After 24 hours, the inside of the reactor was heated to 10°C while maintaining the reaction temperature for 1 hour. -1 The gas inside the reactor was captured by reducing the pressure to 10 torr. The captured gas was cooled to room temperature (18-25°C) to obtain a condensate, and the reactor was opened to obtain a black mass indicating that the reaction was complete.

[0123] X-ray diffraction (XRD) analysis and inductively coupled plasma mass spectrometry (ICP-MS) were performed on the obtained condensate and black mass, respectively, to confirm the aluminum components and contents remaining in the condensate and black mass, and the results are shown in Table 3 below.

[0124] Chlorine compound precursor type Cl / Al catalyst addition Reactor type Reaction temperature Example 1 CCl4(l) 45.5Oⓐ160℃ Example 2 CHCl3(l) 38.2Oⓐ160℃ Example 3 CH2Cl2(l) 48.3Oⓐ160℃ Example 4 C2HCl3(l) 49.5Oⓐ160℃ Example 5 C2Cl4(l) 49.8Oⓐ160℃ Example 6 PVC (s) 50.3Xⓐ250℃ Example 7 PVC (s) 98.5Xⓐ250℃ Example 8 PVC (s) 24.7Xⓐ250℃ Example 9 C2HCl3(l) 49.5Xⓐ160℃ Example 10C2HCl3(l)2.1Oⓑ160℃Example 11C2HCl3(l)49.5Oⓐ160℃Comparative Example 1C2HCl3(l)49.5Oⓐ80℃Comparative Example 2PVC (s)75.3Xⓐ160℃Comparative Example 3HCl (g)5.0Xⓐ200℃Comparative Example 4Cl2(g)5.0Xⓐ200℃

[0125] Location where aluminum component was detectedType of aluminum componentContent of aluminum element remaining in black massCondensateBlack massExample 1Condensate + black massAlCl3Al1.26 wt%Example 2Condensate + black massAlCl3Al1.55 wt%Example 3Condensate + black massAlCl3Al1.37 wt%Example 4Condensate + black massAlCl3Al1.41 wt%Example 5Condensate + black massAlCl3Al1.47 wt%Example 6Condensate + black massAlCl3Al1.16 wt%Example 7Condensate + black massAlCl3Al0.78 wt%Example 8Condensate + black massAlCl3Al2.35 wt%Example 9Condensate + black massAlCl3Al2.26 wt%Example 10Black mass-Al3.71 Weight % Example 11 Black mass - Al 3.73 Weight % Comparative Example 1 Black mass - Al 3.58 Weight % Comparative Example 2 Black mass - Al 3.67 Weight % Comparative Example 3 Black mass - Al 3.71 Weight % Comparative Example 4 Black mass - Al 3.52 Weight %

[0126]

[0127] As shown in Table 3 above, it can be seen that the aluminum removal method according to the present invention is excellent in the effect of removing aluminum present in black mass.

[0128] Specifically, an example in which a mixture of black mass and a chlorine compound precursor was heat-treated at a temperature higher than the temperature at which the chlorine compound precursor vaporizes or thermally decomposes to generate a chlorine (Cl) compound was shown to have an aluminum removal rate of 50% or more as aluminum (Al) in the black mass was converted to aluminum chloride (AlCl3) and volatilized.

[0129] On the other hand, in Comparative Examples 1 and 2, where a mixture of black mass and a chlorine compound precursor was heat-treated at a temperature lower than the temperature at which the chlorine compound precursor was vaporized or thermally decomposed to generate a chlorine (Cl) compound, and in Comparative Examples 3 and 4, where hydrogen chloride gas or chlorine gas was used as the chlorine compound precursor, it was confirmed that chlorination of aluminum in the black mass was not sufficiently achieved, so that almost no aluminum was removed.

[0130] From these results, it can be seen that the aluminum removal method according to the present invention can selectively remove only aluminum (Al) by heat-treating black mass derived from a waste battery with a chlorine compound precursor at a predetermined temperature condition, thereby obtaining lithium (Li) with high purity and recovery rate.

[0131]

[0132] Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood by those skilled in the art or having ordinary knowledge in the art that the present invention can be variously modified and changed within a scope that does not depart from the technical scope of the present invention as set forth in the claims to be described below.

[0133] 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 defined by the patent claims.

Claims

1. A method for removing aluminum from black mass derived from deactivated batteries, Step (S1) of forming a mixture comprising black mass and a chlorine compound precursor; and The method includes the step (S2) of heat-treating the formed mixture to produce dealuminated black mass and aluminum chloride gas, and A method for removing aluminum, wherein the above heat treatment is performed at a temperature above which a chlorine compound precursor vaporizes or thermally decomposes to generate a chlorine compound; and in a range below 300°C.

2. In Paragraph 1, The above-mentioned chlorine compound precursor is a C in which at least one hydrogen is substituted with a chloro group. 1-6 A method for removing aluminum comprising at least one of a hydrocarbon compound and a polymer compound in which at least one hydrogen is substituted with a chloro group.

3. In Paragraph 2, A method for removing aluminum comprising one or more of the above hydrocarbon compounds, selected from tetrachloromethane (CCl4), chloroform (CHCl3), dichloromethane (CH2Cl2), hexachloroethane (C2Cl6), tetrachloroethane (C2H2Cl4), tetrachloroethylene (C2Cl4), and trichloroethylene (C2HCl3).

4. In Paragraph 2, The above polymer compound is an aluminum removal method comprising polyvinyl chloride (PVC).

5. In Paragraph 1, The above heat treatment is an aluminum removal method performed in a reactor capable of maintaining the internal pressure that increases during heat treatment.

6. In Paragraph 1, The above heat treatment is an aluminum removal method performed at a pressure of more than 1 bar and less than or equal to 15 bar.

7. In Paragraph 1, The above mixture is an aluminum removal method further comprising an aluminum-based catalyst containing aluminum chloride (AlCl3).

8. In Paragraph 1, A method for removing aluminum in which the average particle size of the black mass is 0.5 μm to 1,000 μm.

9. In Paragraph 1, A method for removing aluminum in which the black mass comprises more than 0.5 weight% and less than or equal to 5 weight% of aluminum based on the total weight.

10. In Paragraph 1, A method for removing aluminum in which the above-mentioned chlorine compound precursor is mixed with black mass such that the ratio of chlorine atoms contained in the chlorine compound precursor to aluminum atoms contained in the black mass (Cl / Al) is 3 to 100.

11. In Paragraph 1, A method for removing aluminum in which the heat treatment of the black mass and chlorine compound precursor is performed for 10 to 50 hours.

12. In Paragraph 1, The above aluminum removal method is, After the step (S2) of generating dealuminated black mass and aluminum chloride gas, Step (S3) of separating aluminum chloride gas from dealuminumized black mass; and A method for removing aluminum further comprising the step (S4) of condensing separated aluminum chloride gas.

13. In Paragraph 1, The above dealuminated black mass is an aluminum removal method in which the aluminum element content is 3 weight% or less based on the total weight.

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