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

Abstract

The present invention relates to a method for removing aluminum from black mass derived from deactivated batteries. This aluminum removal method selectively removes only aluminum (Al) by heat-treating the black mass derived from waste batteries together with a chlorine compound precursor, thereby enabling the acquisition of lithium (Li) with high purity and recovery rate. Furthermore, this aluminum removal method has the advantages of easy process control and high safety.

Description

[Technical Field]

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

[0002] This application claims priority rights under Korean Patent Application No. 10-2023-0115629 dated August 31, 2023, and Korean Patent Application No. 10-2024-0094796 dated July 18, 2024, and all content disclosed in the documents of said Korean Patent Applications is incorporated herein by reference. [Background technology]

[0003] Lithium batteries, commonly used in automobiles, have a structure in which the positive and negative electrodes are separated by a membrane, with an electrolyte filling the space between them. The most essential component of such lithium secondary batteries is lithium, which is used as the main component of the positive electrode material. Lithium is generally manufactured from lithium-containing ore and is traded at a relatively high price due to the costs of the manufacturing process and the price of the raw material itself. Therefore, in order to lower the unit cost of manufacturing lithium secondary batteries, research is being conducted not only on the performance of lithium secondary batteries themselves, but also on methods for recovering and reusing lithium components from lithium waste batteries that have reached the end of their lifespan.

[0004] To recover lithium contained in the positive electrode, it is necessary to disassemble and release the positive electrode from a deactivated lithium battery and extract the lithium. However, the lithium contained in the positive electrode does not dissolve well even when using various organic solvents due to organic substances (NMP, PVDF, etc.) contained in the organic binder, and it does not easily come off even with the application of ultrasound, and filtration is also difficult.

[0005] Therefore, conventionally, a wet process has been applied to extract lithium from the positive electrode active material by dissolving the crushed waste battery material containing the positive electrode active material (e.g., black mass) in an acidic solvent to separate it into its respective metal components. More specifically, the above wet process involves discharging the waste battery, then crushing the waste battery itself or the positive electrode 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 recovered by immersing it in an acidic solvent to extract lithium.

[0006] However, because the above wet process uses an acidic solvent, significant costs are required to treat the waste acidic solvent generated after the process is completed, and there are problems with environmental pollution caused by by-products. Furthermore, in the above method, the lithium (Li) component in the positive electrode active material and the aluminum (Al) component of the current collector easily aggregate and form slag during the roasting process before acid treatment. In this slag, it is extremely difficult to selectively separate the lithium (Li) component and other components due to the aluminum (Al) component contained within, and even if separation is achieved, the recovery rate is significantly reduced due to impurities. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Korean Published Patent Publication No. 10-2019-0082167 [Overview of the project] [Problems that the invention aims to solve]

[0008] Therefore, the object of the present invention is to provide a technology that can selectively remove only aluminum (Al) from black mass when recovering lithium from deactivated waste batteries, thereby obtaining lithium (Li) with high purity and recovery rate. [Means for solving the problem]

[0009] To solve the above problem, In one embodiment, the present invention In a method for removing aluminum from black mass derived from an inactivated battery, forming a mixture comprising black mass and a chlorine compound precursor (step S1); heat-treating the formed mixture to produce de-aluminized black mass and aluminum chloride gas (step S2), and the heat treatment is performed at a temperature above which the chlorine compound precursor vaporizes or thermally decomposes to generate a chlorine compound; and in a range of less than 300 °C, to provide a method for removing aluminum.

[0010] At this time, the chlorine compound precursor may include one or more of a hydrocarbon compound in which at least one hydrogen is substituted with a chloro group and a polymer compound in which at least one hydrogen is substituted with a chloro group. 1-6 The hydrocarbon compound may include one or more of carbon tetrachloride (CCl4), chloroform (CHCl3), dichloromethane (CH2Cl2), hexachloroethane (C2Cl6), tetrachloroethane (C2H2Cl4), tetrachloroethylene (C2Cl4), and trichloroethylene (C2HCl3).

[0011]

[0012] Further, the polymer compound may include polyvinyl chloride (PVC).

[0013] The heat treatment can be performed in a reactor capable of maintaining an internal pressure that increases during the heat treatment.

[0014] The heat treatment can be performed at a pressure exceeding 1 bar and not exceeding 15 bar.

[0015] The mixture may further include an aluminum-based catalyst containing aluminum chloride (AlCl3).

[0016] Furthermore, the average particle size of the black mass mentioned above can range from 0.5 μm to 1,000 μm.

[0017] Furthermore, the above-mentioned black mass may contain aluminum in an amount exceeding 0.1% by weight but not exceeding 5% by weight relative to the total weight.

[0018] Furthermore, the above-mentioned chlorine compound precursor can be mixed with black mass such that the ratio of chlorine atoms contained in the chlorine compound precursor to aluminum atoms contained in black mass (Cl / Al) is 3 to 100, and the heat treatment of the black mass and chlorine compound precursor can be carried out for 10 to 50 hours.

[0019] On the other hand, the above aluminum removal method is After the step (S2) of producing dealuminized black mass and aluminum chloride gas, Step (S3) involves separating aluminum chloride gas from dealuminized black mass, The procedure may further include the step of condensing the separated aluminum chloride gas (S4).

[0020] Furthermore, the above-mentioned dealuminized black mass may have an aluminum element content of 3% by weight or less based on the total weight. [Effects of the Invention]

[0021] The aluminum removal method according to the present invention selectively removes only aluminum (Al) by heat-treating black mass derived from waste batteries together with a chlorine compound precursor under predetermined temperature conditions, thereby enabling the acquisition of lithium (Li) with high purity and recovery rate. Furthermore, the above aluminum removal method has the advantages of easy process control and high safety. [Brief explanation of the drawing]

[0022] [Figure 1] This is a schematic process diagram illustrating the aluminum removal method according to the present invention. [Figure 2]This is a schematic process diagram illustrating the aluminum removal method according to the present invention. [Modes for carrying out the invention]

[0023] Since the present invention can be modified in various ways and has a variety of embodiments, specific embodiments will be described in detail in the detailed description.

[0024] However, this is not intended to limit the present invention to any particular embodiment, but rather to include all modifications, equivalents, or substitutions that fall within the technical scope of the present invention.

[0025] In the present invention, terms such as "includes" and "have" are intended to specify the presence of features, figures, steps, operations, components, parts, or combinations thereof described in the specification, and do not preemptively exclude the presence or possibility of adding one or more other features, figures, steps, operations, components, parts, or combinations thereof.

[0026] Furthermore, in this invention, when a part such as a layer, film, region, or plate is described as being "on top" of another part, this includes not only the case where it is "directly on top" of the other part, but also the case where another part is located in between. Conversely, when a part such as a layer, film, region, or plate is described as being "below" another part, this includes not only the case where it is "directly below" the other part, but also the case where another part is located in between. Also, in this application, being "on top" may include being located not only at the top but also at the bottom.

[0027] Furthermore, in this specification, "average particle size (D 50"Average particle size" refers to the particle size at which the cumulative value in the particle size distribution reaches 50%, and is also called the median diameter. The above average particle size can be measured using methods commonly applied in this industry. For example, the above average particle size can be measured using an analytical instrument that employs the laser diffraction scattering particle size distribution method according to ISO 13320.

[0028] The present invention will be described in more detail below.

[0029] In one embodiment, the present invention In a method for removing aluminum from black mass derived from deactivated batteries, Step (S1) is to form a mixture containing black mass and a chlorine compound precursor, The process includes the step (S2) of heat-treating the formed mixture to produce dealuminized black mass and aluminum chloride gas, The above heat treatment provides an aluminum removal method performed at a temperature above which the chlorine compound precursor vaporizes or is thermally decomposed to generate chlorine compounds, and below 300°C.

[0030] The present invention relates to a method for selectively removing aluminum originating from the positive electrode current collector of a deactivated lithium waste battery when recovering lithium from the lithium waste battery.

[0031] The above aluminum removal method can be carried out by heat-treating a mixture of lithium-containing material derived from deactivated waste batteries and a chlorine compound precursor. Specifically, the above aluminum removal method can be carried out by performing the steps of forming a mixture containing black mass derived from deactivated batteries and a chlorine compound precursor (S1), and heat-treating the formed mixture to produce dealuminized black mass and aluminum chloride gas (S2). In the above aluminum removal method, the black mass derived from waste batteries is heat-treated together with the chlorine compound precursor to chlorinate the aluminum contained in the black mass. The aluminum chloride (AlCl3) produced at this time undergoes a phase change to a gas at approximately 180°C, so it can be volatilized under high-temperature conditions.

[0032] Therefore, the aluminum removal method according to the present invention can selectively remove aluminum from black mass by converting it to aluminum chloride (AlCl3) and then volatilizing it. The resulting dealuminized black mass has a significantly lower aluminum (Al) content, which allows for the provision of lithium (Li) with high purity and recovery rate in the lithium recovery process.

[0033] Figures 1 and 2 are schematic process diagrams illustrating the steps of the aluminum removal method according to the present invention. Each step will be described in more detail below with reference to Figures 1 and 2.

[0034] 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) means mixing black mass derived from an inactivated battery with a chlorine compound precursor that can provide a chlorine compound to the aluminum (Al) contained in the black mass.

[0035] Here, the above black mass can be particles obtained by discharging an inactivated battery, i.e., a waste battery, and pulverizing itself. In some cases, it can contain black powder obtained by separating only the positive electrode from the waste battery and pulverizing it.

[0036] The above black mass can contain valuable metals derived from the positive electrode active material other than lithium and metals such as aluminum (Al) derived from the positive electrode current collector. Specifically, the above black mass can be derived from a positive electrode having a structure in which a positive electrode active layer containing a positive electrode active material is formed on an aluminum thin plate that is the positive electrode current collector. Therefore, the above black mass can contain valuable metals such as nickel (Ni), cobalt (Co), manganese (Mn), iron (Fe), etc. and aluminum (Al) within a predetermined content range together with lithium (Li).

[0037] Here, the above 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 0.5 Mn 0.5The material may contain, but is not limited to, lithium iron phosphorus oxides such as PO4, either alone or in combination of two or more types.

[0038] The above black mass may contain 1% to 10% by weight of lithium and 15% to 40% by weight of valuable metals (i.e., Ni, Co, Mn) relative to the total weight. The black mass may also contain more than 0.5% by weight of aluminum relative to the total weight, specifically including 1% to 5% by weight, 0.5% to 3% by weight, 1% to 3% by weight, 2% to 4% by weight, 2.5% to 5% by weight, or 2.5% to 4.5% by weight of aluminum. The remaining portion may consist of negative electrode active materials such as graphite and silicon that constitute the negative electrode of the lithium secondary battery, metals such as copper that form the negative electrode current collector, and organic materials that constitute the separation membrane, etc.

[0039] The above black mass can be adjusted so that its average particle size meets a predetermined range. Specifically, the above black mass has an average particle size (D) of 0.5 μm to 1,000 μm. 50 ) can have an average particle size (D) of 0.5μm~750μm, 0.5μm~500μm, 0.5μm~250μm, 0.5μm~100μm, 0.5μm~50μm, 0.5μm~20μm, 0.5μm~10μm, 1μm~15μm, 5μm~15μm, 10μm~200μm, 50μm~500μm, 100μm~300μm, 400μm~700μm, 500μm~900μm, 50μm~150μm, or 5μm~80μm. 50 ) can have.

[0040] If the average particle size of the black mass is smaller than the lower limit of the range described above, aggregation between black masses may occur, and the chlorination reaction of aluminum present in the aggregated black mass may not proceed smoothly. Also, if the average particle size of the black mass is larger than the upper limit of the range described above, chlorine may not penetrate easily into the black mass particles, which may reduce the efficiency of aluminum removal.

[0041] On the other hand, the above-mentioned chlorine-based compound precursors refer to compounds that can provide chlorine-based compounds under high-temperature conditions. The above-mentioned chlorine compounds may include hydrocarbon compounds in which the chlorine atom is activated by vaporization, increasing the internal energy of the molecule, or chlorine (Cl2) gas and / or hydrogen chloride (HCl). The above-mentioned chlorine-based compound precursors may be substances in a liquid or solid state at room temperature (e.g., 18°C ​​to 25°C) in terms of safety and processability due to the chlorine compounds generated during reaction with black mass.

[0042] Specifically, the above chlorine compound precursor is a C compound in which at least one hydrogen atom is substituted with a chloro group. 1-6 It may contain one or more hydrocarbon compounds and polymer compounds in which at least one hydrogen atom is substituted with a chloro group.

[0043] The above hydrocarbon compounds are hydrocarbon compounds having 1 to 6 carbon atoms, i.e., compounds such as methane (1 carbon atom), ethane (2 carbon atoms), and propane (3 carbon atoms), in which one or more hydrogen atoms are substituted with chloro groups (-Cl). For example, the above hydrocarbon compounds may include one or more of the following: tetrachloromethane (CCl4), chloroform (CHCl3), dichloromethane (CH2Cl2), hexachloroethane (C2Cl6), tetrachloroethane (C2H2Cl4), tetrachloroethylene (C2Cl4), trichloroethylene (C2HCl3), etc. The above hydrocarbon compounds may be in a liquid state at room temperature (approximately 20±5°C) and atmospheric pressure (approximately 1 atm).

[0044] The above polymer compound is a high molecular weight compound containing a hydrocarbon chain with a molecular weight of 1,000 g / mol or more, meaning that at least one hydrogen in the hydrocarbon chain is substituted with a chloro group. For example, the above polymer compound may include polyvinyl chloride (PVC). The above polymer compound may be in a solid state at room temperature (approximately 20 ± 5°C) and atmospheric pressure (approximately 1 atm).

[0045] Other materials deemed suitable 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).

[0046] However, gases such as chlorine gas (Cl2) and hydrogen chloride (HCl) have the characteristic of not being highly reactive with aluminum in black mass at low temperatures. Furthermore, these gases are difficult to control during the process, are highly toxic to humans, and have low safety, making them unsuitable as precursors for chlorine compounds.

[0047] Furthermore, in the case of inorganic solvents such as dilute hydrochloric acid, water (H2O) is present. This water reacts preemptively with aluminum (Al) before the chlorine (Cl) in the chlorine compound reacts with the aluminum (Al) present in the black mass, forming aluminum oxide (Al2O3). Since aluminum oxide undergoes a phase change to gas at approximately 2977°C, it is difficult to remove the aluminum by volatilization, and removing it requires a separate, additional purification process, which presents a problem.

[0048] Furthermore, since chlorine-containing metal salts undergo a phase change to a gas at temperatures above approximately 600°C, supplying chlorine from a chlorine compound precursor during the process requires high energy and cost, which is a limitation. In addition, the above metal salts have low reactivity with aluminum (Al) in the black mass and the supplied chlorine (Cl) compound, making it difficult to form aluminum chloride (AlCl3).

[0049] On the other hand, hydrocarbon compounds and / or polymer compounds having a chemical structure in which chlorine is substituted on a chain-like hydrocarbon group are easy to control during the process, and the substances themselves have low toxicity to the human body and are highly safe. Furthermore, the hydrocarbon compounds undergo a phase change to a gas at temperatures below 200°C, easily supplying chlorine elements with increased intramolecular reactivity to the black mass, and the polymer compounds can be thermally decomposed at approximately 240°C to 270°C, supplying chlorine (Cl2) and / or hydrogen chloride (HCl) in gaseous form. Therefore, the hydrocarbon compounds and / or polymer compounds have the advantage of being highly efficient in supplying vaporized hydrocarbon compounds and gaseous chlorine (Cl2) and / or hydrogen chloride (HCl), which are chlorine compounds. The chlorine compounds thus supplied are highly reactive with aluminum (Al) in the black mass, generating aluminum chloride (AlCl3) at a rapid rate, thus having the advantage of being highly effective in removing aluminum (Al) from the black mass.

[0050] The above chlorine compound precursor may be tetrachloromethane (CCl4). Tetrachloromethane (CCl4) has the advantage of being very favorable for the chlorination reaction of aluminum because, when it reacts with aluminum, the Gibbs free energy of aluminum chloride (AlCl3) and the Gibbs free energy of the conversion of aluminum oxide (Al2O3), which may be generated as a byproduct, to aluminum chloride (AlCl3) are both significantly low negative values.

[0051] Furthermore, the above-mentioned chlorine compound precursor may be polyvinyl chloride (PVC). Polyvinyl chloride (PVC) has the characteristics of high safety for human health and process safety. In addition, since polyvinyl chloride (PVC) is in a solid state at room temperature, material storage and management are easy. Moreover, since polyvinyl chloride (PVC) can quantitatively produce gaseous hydrogen chloride (HCl) by thermal decomposition, it has the advantage of being very easy to control the process.

[0052] Furthermore, in step (S1), the black mass and the chlorine compound precursor can be mixed such 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 can be mixed such that the ratio of chlorine atoms to aluminum atoms (Cl / Al) is 3 or greater, and more specifically, it can be mixed so that it is between 3 and 100. For example, the above chlorine compound precursor can be mixed such that the ratio (Cl / Al) of chlorine atoms contained in the chlorine compound precursor to aluminum atoms contained in black mass is 3-80, 3-60, 3-50, 3-30, 3-10, 10-80, 20-70, 30-60, 40-90, 50-100, 50-90, 70-99, 20-30, 30-55, 40-50, 45-55, 20-50, or 60-80.

[0053] For example, if the chlorine compound precursor is a hydrocarbon compound, the chlorine compound precursor can be mixed such that the ratio of chlorine atoms contained in the chlorine compound precursor to aluminum atoms contained in black mass (Cl / Al) is 36 to 53.

[0054] When the above-mentioned chlorine compound precursor is a polymer compound, the above-mentioned chlorine compound precursor can be mixed such that the ratio of chlorine atoms contained in the chlorine compound precursor to aluminum atoms contained in black mass (Cl / Al) is 21-30; 47-53; or 90-99.

[0055] This invention enables highly efficient and economical chlorination of aluminum in black mass without excessive use of the chlorine compound precursor, by ensuring that the atomic ratio range described above is met when mixing black mass and the chlorine compound precursor. Specifically, if the ratio of chlorine atoms to aluminum atoms (Cl / Al) is lower than the lower limit of the atomic ratio range described above, the chlorination of aluminum in black mass will not be sufficient, resulting in a significant reduction in aluminum removal efficiency. Furthermore, if the ratio of chlorine atoms to aluminum atoms (Cl / Al) is higher than the upper limit of the atomic ratio range described above, the chlorination of aluminum in black mass will proceed with high reactivity, but the pressure of the chlorine compound may increase excessively. High-pressure chlorine compounds can reduce process safety and corrode the inside of the reactor. In addition, there is a limitation that economic efficiency decreases due to the excessive use of the chlorine compound precursor.

[0056] The above mixture of black mass and chlorine compound precursor does not contain any components other than black mass and chlorine compound precursor, but may further contain a catalyst to promote the reaction between aluminum and chlorine if the chlorine compound precursor is a hydrocarbon compound.

[0057] The catalyst described above may be an aluminum-based catalyst, specifically aluminum chloride (AlCl3). This aluminum chloride (AlCl3) can react with aluminum (Al) contained in the black mass to produce AlCl and / or AlCl2. The AlCl and / or AlCl2 thus produced can rapidly react with chlorine compounds generated from chlorine compound precursors to produce AlCl3. In other words, this aluminum chloride (AlCl3) can induce the oxidation of aluminum (Al) present in the black mass, thereby promoting the chlorination of aluminum.

[0058] For this reason, the aluminum-based catalyst can be included in a content of 0.001% to 5% by weight based on the total weight of the mixture containing black mass and chlorine compound precursor, specifically in amounts of 0.001% to 3% by weight, 0.001% to 2% by weight, 0.001% to 1% by weight, 0.001% to 0.5% by weight, or 0.1% to 0.5% by weight. When the aluminum-based catalyst is included in an amount less than the lower limit of the above-mentioned content range, it may have only a slight effect in promoting the chlorination of aluminum. Furthermore, when the aluminum-based catalyst is included in an amount greater than the upper limit of the above-mentioned content range, it may react with the ceramic or glass material constituting the reactor to produce silicon tetrachloride (SiCl4) and aluminum silicate (Al2SiO5), or corrode the inside of the reactor, thus requiring an additional step to purify the black mass.

[0059] Next, the aluminum removal method of the present invention includes the step (S2) of heat-treating the formed mixture to produce dealuminized black mass and aluminum chloride gas.

[0060] Step (S2) refers to the process of inducing a reaction between the chlorine atoms (Cl) of the chlorine compound, which have been activated by vaporization and / or thermal decomposition of the chlorine compound precursor under high-temperature conditions, and aluminum (Al) present in the black mass, thereby forming aluminum chloride (AlCl3).

[0061] As one example, when the chlorine compound precursor is a hydrocarbon compound, heat treatment vaporizes the chlorine compound precursor, producing a hydrocarbon compound with activated chlorine atoms as the chlorine compound. These activated chlorine atoms in the hydrocarbon compound then react with solid aluminum (Al) present in the black mass to form aluminum chloride (AlCl3).

[0062] As another example, when the chlorine compound precursor is a polymer, heat treatment causes the chlorine compound precursor to decompose, generating chlorine (Cl2) and / or hydrogen chloride (HCl) in gaseous form. The activated chlorine atoms of the generated chlorine (Cl2) and / or hydrogen chloride (HCl) then react with solid aluminum (Al) present in the black mass to form aluminum chloride (AlCl3).

[0063] At this time, the formed aluminum chloride (AlCl3) is in a gaseous state due to the added heat, so dealuminized black mass can be obtained in which aluminum is selectively removed from solid black mass.

[0064] In this step (S2), the temperature can be adjusted during heat treatment to meet a predetermined range for vaporization and / or thermal decomposition of the chlorine compound precursor. Specifically, the heat treatment in step (S2) can be carried out at a temperature above the temperature at which the chlorine compound precursor vaporizes or is thermally decomposed to produce a chlorine compound, and below 300°C, more specifically at temperatures of 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.

[0065] As one example, the temperature during the heat treatment described above can be adjusted to a temperature above the boiling point (bp) of the hydrocarbon compound for vaporization, i.e., approximately 35°C to 280°C, or approximately 35°C to 200°C, when the chlorine compound precursor is a hydrocarbon compound. Here, the boiling points of the hydrocarbon compounds are as follows: tetrachloromethane (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.

[0066] As another example, the temperature during the heat treatment described above can be adjusted to a temperature of approximately 240°C to less than 300°C for the thermal decomposition of the polymer compound when the chlorine compound precursor is a polymer compound (e.g., polyvinyl chloride), specifically to a temperature of approximately 250°C to 280°C.

[0067] Furthermore, the above heat treatment can be carried out in a closed-system reactor, such as an autoclave, which can apply heat to the reactants while maintaining the internal pressure that increases due to the applied heat. A closed-system reactor can increase the reactivity of the reactants by maintaining the vapor pressure of the reactants, which increases through phase changes during heat treatment such as a solventhermal reaction, and the pressure increased by the products generated by the heat. In other words, by performing heat treatment in a closed-system reactor, the internal pressure that increases due to the chlorine compounds generated from the chlorine compound precursors, which are the reactants, can be maintained, thereby further promoting the chlorination reaction of aluminum in the black mass.

[0068] This allows the heat treatment of the present invention to be carried out under predetermined pressure conditions. Specifically, the heat treatment can be carried out at a pressure of more than 1.0 bar and less than or equal to 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, and 1.5 bar to 7.0 bar. It can be done at pressures of 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.

[0069] During heat treatment, if the pressure inside the reactor is below the lower limit of the range described above, the effect of promoting the chlorination reaction of aluminum in the black mass is minimal, which may result in a low aluminum removal rate. Furthermore, if the pressure inside the reactor exceeds the upper limit of the range described above during heat treatment, damage to the reactor where the reaction takes place may occur, resulting in a limitation of low process safety.

[0070] Furthermore, the above heat treatment can be carried out for 10 to 50 hours. More specifically, the above 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 above heat treatment is performed for a shorter time than the lower limit of the above time range, there is a problem that the aluminum removal rate is low because there is not enough time for the aluminum in the black mass to be converted to aluminum chloride. Also, if the above heat treatment is performed for a longer time than the upper limit of the above time range, it is difficult to obtain an effect such as further improvement in the aluminum removal rate, so the process efficiency and economic efficiency may be low.

[0071] Furthermore, the above heat treatment can be carried out under conditions in which moisture (H2O) and oxygen (O2) are excluded from the reaction. Specifically, in this step (S2), after introducing black mass and chlorine compound precursor into the reactor, a vacuum can be created inside to remove moisture (H2O) and oxygen (O2) present inside the reactor. Subsequently, inactive gases such as helium (He), neon (Ne), nitrogen (N2), and argon (Ar) can be injected into the reactor to control the pressure inside the reactor to 1 bar before heat treatment.

[0072] Aluminum chloride (AlCl3) is highly reactive and readily forms aluminum chloride hydrate (AlCl3·6H2O) upon contact with moisture or oxygen in the air. Since the above aluminum chloride hydrate (AlCl3·6H2O) is converted to aluminum oxide (Al2O3) at high temperatures, it becomes difficult to remove aluminum from the 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 before heat treatment, thereby improving the aluminum removal rate from the black mass.

[0073] The reactor used in this invention may be limited in the materials that make up its interior. Specifically, the reactor may be made of ceramic, glass, or stainless steel, and the inside of the reactor may be coated with a fluoropolymer such as polytetrafluoroethylene (PTFE) for purposes such as heat resistance and chemical resistance.

[0074] On the other hand, as shown in Figure 2, the aluminum removal method according to the present invention may further include, after the step of generating dealuminized black mass and aluminum chloride gas (S2), the step of separating aluminum chloride gas from the dealuminized black mass (S3) and the step of condensing the separated aluminum chloride gas (S4).

[0075] Specifically, the above aluminum removal method involves heat-treating a mixture of black mass and a chlorine compound precursor for a predetermined time to produce solid dealuminized black mass and gaseous aluminum chloride (S2). Then, while maintaining the heat treatment temperature for 0.5 to 2 hours, a valve in a pipe separately introduced into the reactor is opened, and the inside of the reactor is opened for approximately 10 minutes. -1 The pressure can be reduced to torr. The aluminum chloride in gaseous state generated inside the reactor by the above reduction can be separated separately (S3). Here, the preset time may be the same as the heat treatment execution time described above. After being collected, the separated aluminum chloride can be cooled to a temperature below 150°C, preferably room temperature (18°C to 25°C), and condensed (S4).

[0076] The black mass obtained by the above process may be dealuminized black mass with a significantly low aluminum content, as aluminum has been selectively removed. Specifically, the aluminum removal method according to the present invention can remove aluminum from black mass with high efficiency, and the aluminum removal efficiency may be 40% or more. Specifically, the above aluminum removal method can have an aluminum removal efficiency of 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 50% to 99%, 60% to 95%, 50% to 80%, 55% to 75%, 60% to 70%, 80% to 99%, or 70% to 90%.

[0077] As a result, black mass from which aluminum has been removed according to the present invention, i.e., dealuminized black mass, may have a significantly lower aluminum content. Here, the aluminum content in dealuminized black mass may vary depending on the proportion of aluminum contained in the black mass before dealuminization.

[0078] As one example, a black mass in which the aluminum content before aluminum removal is performed is 3% to 4% by weight may have an aluminum content of 3% or less by weight based on the total weight after the aluminum removal method according to the present invention, and specifically, based on the total weight of the black mass, it may be 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.

[0079] The aluminum removal method according to the present invention, having the above-described configuration, can selectively remove only the aluminum (Al) contained in the black mass by heat-treating the black mass derived from waste batteries together with a chlorine compound precursor, thereby enabling the acquisition of lithium (Li) from the black mass with high purity and recovery rate. Furthermore, the above aluminum removal method has the advantages of easy process control and high safety.

[0080] The present invention will be described in more detail below with reference to examples and experimental examples.

[0081] However, the following examples and experimental examples are illustrative of the present invention, and the content of the present invention is not limited to the following examples and experimental examples. [Examples]

[0082] <Examples 1-11 and Comparative Examples 1-4. Removal of aluminum from black mass> As the positive electrode active material, LiNi 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 electrode active layer containing O2 is provided on an aluminum thin plate, and a negative electrode having a structure in which a negative electrode active layer containing graphite as a negative electrode active material is provided on a copper thin plate.

[0083] The prepared lithium secondary battery cells are crushed, and the average particle size (D 50 Black mass with a size of 8 μm to 12 μm was obtained. Inductively coupled plasma mass spectrometry (ICP-MS) was then performed on the obtained black mass to measure the content of metal components per kilogram of black mass. The results are shown in Table 1 below.

[0084] [Table 1]

[0085] As chlorine compound precursors, the following were prepared: (1) hydrocarbon compounds of tetrachloromethane (CCl4), (2) chloroform (CHCl3), (3) dichloromethane (CH2Cl2), (4) trichloroethylene (C2HCl3), and (5) tetrachloroethylene (C2Cl4) (all liquids); (6) polymer compounds of polyvinyl chloride (PVC); and (7) hydrogen chloride (HCl) gas and (8) chlorine (Cl2) gas (all gases). In addition, aluminum chloride (AlCl3(anhydous), purity: 98.0%) was prepared as a catalyst.

[0086] Furthermore, as reactors, (a) an autoclave made of ceramic material coated with polytetrafluoroethylene (PTFE) and (b) an aluminum crucible that does not maintain the internal pressure that increases during heat treatment were prepared.

[0087] The previously prepared black mass was placed into a reactor (capacity: 250 ml), and chlorine compound precursors were injected so that the ratio of chlorine (Cl) atoms in the chlorine compound precursor to aluminum (Al) atoms in the black mass (Cl / Al) was adjusted as shown in Table 2 below. After that, the reactor was sealed.

[0088] A vacuum was created inside the sealed reactor to remove the water (H2O) and oxygen (O2) present inside the reactor, and aluminum chloride (AlCl3), the catalyst, was added to a total weight of 0.2% of the total mixture. Nitrogen (N2) gas was injected into the reactor to adjust the internal pressure to 1 bar. Here, if the chlorine compound precursor was (7) hydrogen chloride (HCl) gas or (8) chlorine (Cl2) gas, only black mass was added to the reactor to replace the water and oxygen inside the reactor with hydrogen chloride (HCl) gas or chlorine (Cl2) gas, and the internal pressure of the reactor was adjusted to 1 bar.

[0089] Subsequently, 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, starting from the point when the above reaction temperature was reached.

[0090] After 24 hours, maintain the reaction temperature for 1 hour while stirring the inside of the reactor for 10 minutes. -1 The reactor was depressurized to Torr, and the gas inside the reactor was collected. The collected gas was cooled to room temperature (18°C to 25°C) to obtain condensate, and the reactor was opened to obtain black mass, indicating that the reaction had finished.

[0091] X-ray diffraction (XRD) analysis and inductively coupled plasma mass spectrometry (ICP-MS) were performed on the obtained condensates and black mass, respectively, to confirm the aluminum components and their content remaining in the condensates and black mass. The results are shown in Table 3 below.

[0092] [Table 2]

[0093] [Table 3]

[0094] As shown in Table 3 above, the aluminum removal method according to the present invention is excellent in its effect of removing aluminum present in black mass.

[0095] Specifically, in an example where a mixture of black mass and a chlorine compound precursor was heat-treated at a temperature above the temperature at which the chlorine compound precursor vaporizes or is thermally decomposed to generate chlorine (Cl) compounds, it was shown that the aluminum (Al) in the black mass was converted to aluminum chloride (AlCl3) and volatilized, resulting in an aluminum removal rate of 50% or more.

[0096] 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 below the temperature at which the chlorine compound precursor vaporizes or is thermally decomposed to generate chlorine (Cl) compounds, 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 the chlorination of aluminum in the black mass was insufficient and almost no aluminum was removed.

[0097] These results show that the aluminum removal method according to the present invention can selectively remove only aluminum (Al) by heat-treating the black mass derived from waste batteries together with a chlorine compound precursor under predetermined temperature conditions, thereby enabling the acquisition of lithium (Li) with high purity and recovery rate.

[0098] While preferred embodiments of the present invention have been described above with reference to those skilled in the art or those with ordinary knowledge in the art, it will be understood that the present invention can be modified and altered in various ways without departing from the technical domain of the present invention as described in the claims below.

[0099] Therefore, the technical scope of the present invention is not limited to what is described in the summary of the invention in the specification, but can be defined by the claims.

Claims

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

2. The chlorine compound precursor is a C compound in which at least one hydrogen atom is substituted with a chloro group. １－６ The aluminum removal method according to claim 1, comprising one or more of the hydrocarbon compounds and polymer compounds in which at least one hydrogen is substituted with a chloro group.

3. The hydrocarbon compound is carbon tetrachloride (CCl ４ ), chloroform (CHCl ３ ), dichloromethane (CH ２ Cl ２ ), hexachloroethane (C ２ Cl ６ ), tetrachloroethane (C ２ H ２ Cl ４ ), tetrachloroethylene (C ２ Cl ４ ), and trichloroethylene (C ２ HCl ３ ), and the method for removing aluminum according to claim 2, which contains one or more of them.

4. The aluminum removal method according to claim 2, wherein the polymer compound includes polyvinyl chloride (PVC).

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

6. The aluminum removal method according to claim 1, wherein the heat treatment is performed at a pressure of more than 1 bar and less than or equal to 15 bar.

7. The aforementioned mixture is aluminum chloride (AlCl ３ The aluminum removal method according to claim 1, further comprising an aluminum-based catalyst containing ).

8. The aluminum removal method according to claim 1, wherein the average particle size of the black mass is 0.5 μm to 1,000 μm.

9. The aluminum removal method according to claim 1, wherein the black mass contains aluminum in an amount exceeding 0.5% by weight and not exceeding 5% by weight, relative to the total weight.

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

11. The aluminum removal method according to claim 1, wherein the heat treatment of the black mass and the chlorine compound precursor is carried out for 10 to 50 hours.

12. The aluminum removal method described above is: After step (S2) of generating dealuminized black mass and aluminum chloride gas, Step (S3) of separating aluminum chloride gas from dealuminized black mass, The aluminum removal method according to claim 1, further comprising the step (S4) of condensing the separated aluminum chloride gas.

13. The aluminum removal method according to claim 1, wherein the dealuminized black mass has an aluminum element content of 3% by weight or less based on the total weight.

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