Valuable metal recovery alloy

Abstract

The present invention relates to a valuable metal recovery alloy comprising: a valuable metal recovery alloy core part; a porous intermediate layer positioned on the core part; and a Cu-containing coating layer positioned on the porous intermediate layer and on at least a portion of the surface of the porous intermediate layer.

Description

Precious metal recovery alloy

[0001] The present invention relates to a valuable metal recovery alloy recovered from waste batteries, specifically to a valuable metal recovery alloy comprising a copper (Cu) coating layer recovered from waste batteries.

[0002] This application claims priority to Korean Patent Application No. 10-2024-0191461, filed on December 19, 2024, the entire contents of which are incorporated herein by reference.

[0003] As global demand for electric vehicles (EVs) intensifies, the issue of disposing of waste batteries generated from these vehicles is emerging as a social concern. Lithium-ion batteries, which serve as the primary raw material for these waste batteries, contain organic solvents, explosive substances, and heavy metals such as Ni, Co, Mn, Fe, and P. However, Ni, Co, Mn, Fe, P, and Li are valuable metals with high scarcity value, making the recovery and recycling processes for lithium-ion batteries after disposal a critical area of ​​research.

[0004] Specifically, the lithium secondary battery comprises copper and aluminum used as current collectors, oxides containing Li, Ni, Co, Mn, Fe, and P constituting the cathode material, and graphite and Si used as the anode material, and includes a separator that separates the cathode material and the anode material, and an electrolyte injected into the separator. The solvent used as the solvent and salt constituting the electrolyte mainly consists of a mixture of carbonate organic materials such as ethylene carbonate and propylene carbonate.

[0005] To utilize the aforementioned waste batteries, interest is emerging in waste battery recycling processes that involve crushing the waste batteries to produce intermediate materials such as shredded waste batteries or black powder, followed by subsequent processing to recover valuable metals. Specifically, the major components of waste batteries consist of expensive valuable metal elements such as Ni, Co, Mn, Li, Fe, and P.

[0006] The above waste battery is, for example, a secondary battery that has reached the end of its lifespan after being used for a cycle of 5 to 10 years, and recycling the main components of the above waste battery is absolutely necessary from an environmental and cost perspective. The above waste battery undergoes conventional crushing, grinding, or sorting processes to produce a mixture of cathode and anode materials in the form of black powder, which is an intermediate product.

[0007] Methods for recovering valuable metals from the black powder are broadly classified into wet and dry processes. The wet process involves using acid to dissolve components within the raw material, primarily using sulfuric acid, and dissolving metal components within the raw material through a leaching process. Key process parameters include pH and temperature, and the particle size of the raw material also has a significant impact.

[0008] The process involves selectively extracting specific components from the leached valuable metals, a process called solvent extraction. The solvent extraction process utilizes an extractant capable of selectively extracting components based on pH. The selectively extracted components are then subjected to a final crystallization process to produce high-concentration metal sulfates, which are subsequently sold as products. During this series of processes, wastewater and waste coal dust are generated as waste at the water discharge facility.

[0009] In addition, the above dry process involves heat treatment of the black mass at high temperatures to form valuable metals in the form of alloys rather than oxides. For example, an alloy of nickel and cobalt is formed through heat treatment at high temperatures. The alloy obtained in this way is also recycled as a raw material for batteries through a wet process, such as leaching or extraction. Key factors in this process include pH, temperature, and the type of oxidizer. In the case of alloys produced through the dry process, the alloy particle size can also act as a major factor in the efficiency of the wet process.

[0010] When Black Mass, which is a mixture of all valuable metals and resources, is fed into wet smelting in this manner, the efficiency of the process is reduced, the amount of various reagents such as sulfuric acid increases, the solvent extraction process to increase concentration becomes complex, and the problem of high impurity content in the manufactured alloy is caused.

[0011] Therefore, there is a need to develop technology to increase the content and purity of valuable metal recovery alloys obtained from waste batteries.

[0012] One objective of the present invention is to provide a valuable metal recovery alloy having a copper (Cu) coating layer formed thereon, which is recovered from waste batteries.

[0013] A valuable metal recovery alloy according to one embodiment of the present invention comprises: an alloy core portion; a porous intermediate layer located on the core portion; and a Cu-containing coating layer located on the surface of the porous intermediate layer.

[0014] The above Cu-containing coating layer can be coated on an area of ​​10% or more of the surface area of ​​the porous intermediate layer.

[0015] The above porous intermediate layer may include one or more pore channels with a length of 10㎛ or more.

[0016] The average thickness of the above porous intermediate layer may be 3㎛ or more.

[0017] Based on the cross-sectional area of ​​the above-mentioned valuable metal recovery alloy, the area of ​​the voids included in the intermediate layer based on the area of ​​the above-mentioned porous intermediate layer may be 40% or more.

[0018] The thickness of the coating layer may be 1 to 50 μm.

[0019] The average particle size of the above valuable metal recovery alloy may be 100 to 500 μm.

[0020] The copper (Cu) content included in the above valuable metal recovery alloy may be 12.0 to 40.0 wt%.

[0021] The above Cu-containing coating layer can be coated on an area of ​​10% or more of the surface area of ​​the porous intermediate layer.

[0022] The above Cu-containing coating layer can be coated over the entire surface area of ​​the porous intermediate layer.

[0023] The valuable metal recovery alloy produced according to the method for producing a valuable metal recovery alloy according to one embodiment of the present invention has a copper coating layer formed thereon and has the advantage of high purity due to the concentration of Cu.

[0024] In addition, since most of the Cu is separated during the leaching step, the Cu extraction process can be omitted in the subsequent solvent extraction.

[0025] In addition, adding an aqueous copper salt solution when leaching NCM alloys in a sulfuric acid solution has the advantage of reducing the amount of oxidizing agent generally consumed during leaching.

[0026] Figure 1 schematically shows the structure of a valuable metal recovery alloy according to one embodiment of the present invention.

[0027] FIG. 2 schematically illustrates the manufacturing process of a valuable metal recovery alloy according to one embodiment of the present invention.

[0028] Figure 3 shows an SEM image of a valuable metal recovery alloy according to Example 1 of the present invention.

[0029] Figure 4 shows an SEM image of a valuable metal recovery alloy according to Comparative Example 1 of the present invention.

[0030] Figure 5 shows a cross-sectional SEM-FIB image of a valuable metal recovery alloy according to Example 1 of the present invention.

[0031] Figure 6 shows a cross-sectional SEM-FIB image of a valuable metal recovery alloy according to Comparative Example 1 of the present invention.

[0032] Figure 7 shows the EPMA analysis results for a cross-section of a valuable metal recovery alloy according to Example 1 of the present invention.

[0033] Figure 8 shows the EPMA analysis results for a valuable metal recovery alloy according to one embodiment of the present invention.

[0034] Figure 9 shows the EPMA analysis results for a cross-section of a valuable metal recovery alloy according to Comparative Example 1 of the present invention.

[0035] Terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited thereto. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without departing from the scope of the present invention.

[0036] The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. As used in the specification, the meaning of "comprising" specifies certain characteristics, areas, integers, steps, actions, elements, and / or components, and does not exclude the presence or addition of other characteristics, areas, integers, steps, actions, elements, and / or components.

[0037] When it is stated that one part is "on" or "on" another part, it may be directly on or on the other part, or another part may be involved in between. In contrast, when it is stated that one part is "directly on" another part, no other part is interposed in between.

[0038] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined.

[0039] In this specification, the term “combination(s) of these” described in the Markush-type expression means one or more mixtures or combinations selected from the group consisting of the components described in the Markush-type expression, and means including any one or more selected from the group consisting of said components.

[0040] Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0041] Figure 1 schematically shows the structure of a valuable metal recovery alloy according to one embodiment of the present invention.

[0042] Referring to FIG. 1, a valuable metal recovery alloy according to one embodiment of the present invention varies depending on the shape of the raw material and may be approximately spherical in shape and may include a core portion and a porous intermediate layer located on the core portion; and a coating layer located outside the porous intermediate layer.

[0043] In FIG. 1, the coating layer is shown as being positioned to cover the entire outer surface of the porous intermediate layer, but this is illustrated for convenience of explanation, and the coating layer may be positioned to cover the entire or a part of the surface of the porous intermediate layer.

[0044] In the present invention, an intermediate layer may be located between the coating layer and the core portion.

[0045] The above intermediate layer may have a porous structure and may have one or more void channels observed in the cross-section of the valuable metal recovery alloy.

[0046] The above-mentioned void channel may refer to long, connected voids observed when the cross-section of a valuable metal recovery alloy is analyzed by SEM-FIB.

[0047] The length of the above-mentioned pore channel may be 10㎛ or more. The average width of the above-mentioned pore channel may be 1 to 10㎛.

[0048] In the present invention, the intermediate layer may include one or more pore channels with a length of 10 μm or more, and specifically, may include one or more pore channels with a length of 15 μm or more and 20 μm or more.

[0049] In the invention, the thickness of the intermediate layer may be 5㎛, specifically 5 to 50㎛, and the pore area in cross-section may occupy 40% or more of the total intermediate layer area, specifically 50 to 90%.

[0050] In the present invention, since the valuable metal recovery alloy includes the intermediate layer, the Cu coating layer and the core part are separated, and the leaching rate can be increased by raising the reaction surface area during Cu leaching. Additionally, since Cu located in the coating layer can be preferentially separated during the recovery process, there is an advantage of recovering high-purity Cu metal using a relatively simple and low-cost method.

[0051] In addition, since the valuable metal recovery alloy in the present invention includes the porous intermediate layer, there is an advantage in that separation by composition becomes easier by forming particles in which the coating Cu metal and the core metal are separated during the process of crushing the valuable metal recovery alloy.

[0052] The above core portion may be formed by performing a high-temperature reduction heat treatment process on a battery or battery crushed material obtained by crushing the battery, and may be an alloy mainly comprising NCM and Cu, and specifically may include Ni, Mn and Co.

[0053] In the present invention, the valuable metal recovery alloy may contain 18.2 to 37.7 wt% of Ni based on the total weight.

[0054] In the present invention, Mn may be included in an amount of 6.3 to 11.2 wt% based on the total weight of the valuable metal recovery alloy.

[0055] In the present invention, the valuable metal recovery alloy may contain 6.5 to 12.0 wt% of Co based on the total weight.

[0056] The coating layer may contain Cu, and the average thickness may be 1 to 50 μm, specifically 1 to 50 μm or 5 to 20 μm.

[0057] In the present invention, based on the total weight of the valuable metal recovery alloy, Cu may be included in an amount of 10.0 to 50.0 wt%, and specifically, 10.0 to 40.0 wt% and 10.0 to 30.0 wt%.

[0058] In the present invention, the Cu-containing coating layer may be coated on an area of ​​10% or more of the surface area of ​​the porous intermediate layer, specifically on an area of ​​50% or more, 90% or more, 95% or more, and may also be coated on an area of ​​100%.

[0059] In the present invention, the valuable metal recovery alloy includes a Cu coating layer located on the surface of a porous intermediate layer, so that the Cu located on the coating layer can be preferentially separated in the Cu single metal recovery process using the valuable metal recovery alloy, thereby having the advantage of recovering high-purity Cu metal in a simple and low-cost manner.

[0060] In the present invention, the average particle size of the valuable metal recovery alloy may be 100 to 500 μm, specifically 100 to 200 μm. The particle size of the valuable metal recovery alloy is the average value of the longest length between the major axis, which is the longest length in the particle image observed by SEM, and the length perpendicular to the major axis, and the average value of the particle sizes of three or more valuable metal recovery alloy particles is defined as the average particle size of the valuable metal recovery alloy.

[0061] In the present invention, the length of the pore channel may refer to the longest length of a single connected pore with a long shape observed in the SEM-FIB image. The width of the pore channel refers to the length perpendicular to the length of the pore channel, and the average width refers to the average of three or more width lengths spaced continuously by 3 μm in the SEM-FIB image.

[0062]

[0063] FIG. 2 schematically illustrates the manufacturing process of a valuable metal recovery alloy according to one embodiment of the present invention.

[0064] Hereinafter, a method for manufacturing the valuable metal recovery alloy in the present invention will be explained with reference to FIG. 2.

[0065] A method for recovering valuable metals according to another embodiment of the present invention includes the step of preparing a battery and the step of high-temperature heat treatment of the battery or the battery crushed from the battery.

[0066] As the method for recovering valuable metals according to the present invention is performed at a temperature at which at least a portion of the battery or the battery crushed material begins to be reduced, a valuable metal recovery composition can be formed comprising a reactant having a flake shape as described above, wherein the alloy is partially melted and disposed on at least a portion of the base material and the surface of the base material.

[0067]

[0068] The valuable metal recovery composition formed by reducing the above-mentioned spent lithium battery contains nickel (Ni) element and additionally contains one or more selected from cobalt (Co), manganese (Mn), copper (Cu), and graphite (C), and can satisfy one or more of the following (1) to (4).

[0069] (1) Based on the weight of Ni, the content of Co is 27.0 to 32.0 wtl%

[0070] (2) Based on the weight of Ni, the Mn content is 27.0 to 32.0 wt%

[0071] (3) The content of Cu based on the weight of Ni is 11.0 to 25.0 wt%

[0072] (4) The content of C based on the weight of Ni is 16.0 to 22.0 wt%

[0073] In the present invention, by satisfying the above conditions, the valuable metal recovery composition can produce an alloy coated with a high content of Cu.

[0074] A detailed description of the above-mentioned valuable metal recovery composition may refer to the foregoing to the extent that it is not contradictory.

[0075] In the step of preparing the battery, the battery may include end-of-life batteries, cathode materials such as scrap, jelly rolls, and slurries constituting the waste battery, defective products generated during the manufacturing process, residues within the manufacturing process, and generated debris, for example, waste materials within the manufacturing process of a lithium-ion battery. In this way, the waste battery can be prepared as the battery to recycle the battery.

[0076] In one embodiment, the step of preparing the battery may include a pretreatment step for the battery. Specifically, by including the pretreatment step, explosive substances such as the electrolyte within the battery can be removed to increase safety in subsequent processes and maximize the efficiency of recovery and separation of valuable metals.

[0077] In one embodiment, the step of pre-treating the battery may include the step of discharging the battery. The step of discharging the battery may pre-treat the battery by various methods, such as water discharge or electric discharge, as a non-limiting example.

[0078] When the step of discharging the battery is performed by electric discharge, the voltage of the battery can be reduced to control the voltage of the cell within the battery. For example, the voltage of the battery can be controlled to a voltage of 0 to 4.2 V relative to the cell within the battery.

[0079] The step of treating the battery at a low temperature below a minimum temperature according to the voltage of the battery may be a step of freezing and stabilizing the electrolyte contained within the battery. By treating the battery below a minimum temperature, it is possible to prevent a fire caused by hazardous materials, such as the electrolyte, when the battery is crushed.

[0080] In one embodiment, the low-temperature treatment step may be a step of treating the battery at 10°C or lower. Specifically, when the voltage of the battery is 1.0V or lower, the low-temperature treatment step may treat the battery at a temperature of 0°C or lower. More specifically, when the voltage of the battery is 1.5 to 2.0V, the battery may be treated at a low temperature of -15°C or lower. More specifically, when the voltage of the battery is approximately 2.5V, the battery may be treated at a low temperature of -30°C or lower. More specifically, when the voltage of the battery is 3 to 3.5V, the battery may be treated at a low temperature of -50°C or lower.

[0081] In this way, the battery has the advantage of being able to be safely crushed in the crushing process by performing low-temperature treatment within a specific temperature range according to the cell reference voltage of the battery.

[0082] As the step of performing low-temperature treatment on the battery within the above temperature range is performed, the voltage remaining in minutely within the battery, for example, about 2V to 3V, is reduced to near 0V. Consequently, even if a short circuit occurs where the positive and negative electrodes come into direct contact, no battery reaction occurs, so the battery temperature does not increase, and thus no gas generation or combustion of the electrolyte occurs. Furthermore, since the electrolyte is in a frozen state or a state where vaporization is suppressed, the mobility of lithium ions is very low, so the current conduction characteristics due to the movement of lithium ions can be significantly reduced, and since vaporization of the electrolyte does not occur, flammable gases such as ethylene, propylene, and hydrogen can not be generated.

[0083] If the above low-temperature treatment step is performed at a temperature higher than the above temperature range, the voltage remaining inside the battery does not drop to 0V, which may cause a battery reaction due to a short circuit, and the electrolyte is not completely frozen, making it unsuitable. In this way, the battery treatment method includes a low-temperature treatment step before crushing a battery such as a lithium secondary battery, thereby preventing the risk of fire that may occur during the battery crushing process.

[0084] The step of crushing the frozen battery may refer to a process of applying impact or pressure to the battery so that a portion of the battery detaches from the battery. In one embodiment, the step of crushing the battery may refer to a process of grinding the battery, a process of cutting the battery, a process of compressing the battery, and any combination thereof. Specifically, the crushing step may include any process that destroys the battery to obtain small-sized crushed material.

[0085] In one embodiment, the step of crushing the battery may include all processes of compressing the frozen battery or destroying the battery by applying an external force such as shear force or tensile force. The step of crushing the battery may be carried out, for example, using a crusher.

[0086] In one embodiment, the step of crushing the battery may be performed at least once. Specifically, the crushing step may be performed at least once, either continuously or discontinuously.

[0087] In one embodiment, the step of crushing the battery may be carried out under conditions of supplying an inert gas, carbon dioxide, nitrogen, water, or a combination thereof, or under vacuum conditions of 100 torr or less. For example, when the process of freezing the battery is carried out by cooling it in a temperature range of -60 to -20°C, or under the aforementioned conditions, the supply of oxygen can be suppressed to prevent the electrolyte from reacting with oxygen, thereby preventing an explosion caused by this, and the vaporization of the electrolyte can be suppressed so as not to generate flammable gases such as ethylene, propylene, or hydrogen.

[0088] In one embodiment, the step of crushing the battery may be performed such that the maximum size of the battery crushed material is 100 mm or less. Specifically, the size of the battery crushed material may be 50 mm or less. If the maximum size of the battery crushed material is 100 mm or more, the heat generated due to instability as the battery crushed material is crushed rises to a temperature range of 120°C, which is the average vaporization temperature of the electrolyte, and safety issues such as fire may occur.

[0089] In one embodiment, the battery fragment obtained through the step of crushing the battery may have a layered structure comprising a separator having a positive or negative electrode laminated on at least one surface. Specifically, the layered structure may include a configuration in which a positive or negative electrode is included on one surface or both surfaces of the separator based on the separator. More specifically, the number of layers of the layered structure may correspond to the number of separators. For example, the layered structure may include any one of a positive-separator-negative electrode, positive-separator, separator-positive electrode, separator-negative electrode, or negative-separator, and for example, a positive-separator-negative electrode-separator-positive-separator-negative electrode structure may have a three-layer layered structure. Specifically, the unit battery fragment may have a predetermined thickness in the thickness direction as at least one layer is laminated.

[0090] In one embodiment, the battery crusher may have a layered structure having a stacked structure of one or more to seven layers. Specifically, the layered structure may have a stacked structure of one or more to five layers. As the layered structure is stacked within the above range, the temperature rise of the crusher is minimized, and the heating time can be appropriately taken. If the layered structure is stacked thicker than the upper limit of the above range, the temperature rise increases excessively, and the heating time also increases, leading to a problem of causing a fire as combustion occurs.

[0091] In one embodiment, the size of the battery shredder may be 100 mm or less based on the major axis, which is the longest axis among the width, length, and height directions. Specifically, the size of the battery shredder may be 50 mm or less. By satisfying the aforementioned range for the size of the battery shredder, the possibility of fire occurring in subsequent processes can be reduced. If the size of the unit battery shredder is excessively large, there is a problem in that the temperature of the battery shredder itself rises to 100 ℃ or higher, increasing the likelihood of fire.

[0092] The step of high-temperature heat treatment of the battery or the battery fragments obtained by crushing the battery may be performed at a temperature at which at least a portion of the battery or the battery fragments begins to be reduced. Specifically, the heat treatment process may be performed at a temperature above which the positive electrode current collector is deformed, above which partial melting of the negative electrode current collector occurs, and below which lithium vaporizes and is lost.

[0093] In one embodiment, the temperature at which reduction begins may be 700 to 1,250 ℃. Specifically, the temperature may be performed in the range of 800 to 1,200 ℃, and more specifically, in the range of 900 to 1,100 ℃. As the high-temperature heat treatment step is performed in the aforementioned temperature range, a flake-shaped reactant can be easily formed in which the alloys constituting the anode active material partially melt while partially maintaining the shape of the current collector.

[0094] If the above temperature exceeds the upper limit of the aforementioned range, there is a problem in that the recovery rate of valuable metals decreases as lithium vaporizes and is lost. If the above temperature exceeds the lower limit of the aforementioned range, there is a problem in that the structure of the current collector is not deformed or the melting of the alloy is not performed smoothly.

[0095] In one embodiment, the high-temperature heat treatment step may be performed at a heating rate of 3°C or more per minute. Specifically, the heating rate may be 5°C or more per minute, more specifically 8 to 20°C. By performing the high-temperature heat treatment step within the heating rate range, there is an advantage that nucleation is easier than growth of the alloy.

[0096] If the above heating rate range exceeds the lower limit of the aforementioned range, smooth nucleation does not occur, and growth becomes relatively easy, leading to a problem where metal particles become coarse; the formation of such coarse alloys results in a decrease in the leaching rate during subsequent processes.

[0097] In one embodiment, the high-temperature heat treatment step may be performed under conditions where the O2 volume fraction is less than 5%. In one embodiment, the high-temperature heat treatment step may be performed in an atmosphere containing an inert gas, and the inert gas may be performed under conditions where the volume fraction is less than 1%. The inert gas may include at least one of argon and nitrogen, and may be, for example, argon gas. By performing the high-temperature heat treatment step at the aforementioned oxygen volume fraction and inert gas volume fraction, the reduction process is easily performed, allowing for the effective recovery of valuable metals containing valuable metals as a component. Furthermore, if the oxygen content deviates from the aforementioned range, an excess amount of oxygen combines with the battery crushed material components within the reduction reaction to form carbon dioxide, which is gasified along with lithium, and consequently, there is a problem in that the recovery of lithium, a valuable metal, is not easy.

[0098] In the present invention, by heat-treating the waste battery at the temperature in the reducing atmosphere, there is an advantage of effectively removing residual organic matter present in the waste battery and reducing metal elements to effectively separate them by material.

[0099] In the present invention, the valuable metal recovery composition may vary depending on the type of positive electrode active material included in the waste battery, and specifically may include Li compounds, Cu, graphite (C), and other valuable metals or valuable metal compounds. For example, in the case of a waste battery containing an NCM-based positive electrode active material, it may mainly include NCM alloy, Li compounds, Cu, and graphite.

[0100] The organometallic recovery composition used as a raw material for manufacturing a valuable metal recovery alloy (Cu-coated NCM alloy) in the present invention may comprise at least 45% by weight of a valuable metal and the remainder being impurities, based on 100% by weight of the total composition. The valuable metal recovery alloy may comprise at least one of a valuable metal such as nickel (Ni), cobalt (Co), manganese (Mn), lithium (Li), graphite (C), aluminum (Al), and copper (Cu), and the remainder being impurities.

[0101] In this specification, the term "valuable metal" may refer to expensive metal components included in the battery, and may refer to nickel, cobalt, manganese, aluminum, copper, and lithium. In one embodiment, the valuable metal may be 70 weight percent or more.

[0102] In one embodiment, the valuable metal recovery composition may contain 3 weight% or more of copper (Cu), specifically in a range of 4.7 to 15.1 weight%. If the copper content deviates from the upper limit of the range, there is a problem in that the leaching rate of the metal is low in the leaching process and an excessive amount of oxidizing agent is required, leading to increased process costs.

[0103] Meanwhile, although a lower Cu content in the NCM alloy is advantageous for leaching, it is difficult to separate 100% of Cu by magnetic separation because Cu has the lowest melting point in the high-temperature reduction process and forms an alloy together with NCM alloy. Therefore, the NCM alloy contains at least 3% copper.

[0104] The above valuable metal recovery composition may have a nickel (Ni) content of 42.2 to 59.8 wt%.

[0105] The above valuable metal recovery composition may have a manganese (Mn) content of 11.4 to 19.1 wt%.

[0106] The above valuable metal recovery composition may have a cobalt (Co) content of 11.6 to 18.9 wt%.

[0107] In one embodiment, the average particle size of the valuable metal recovery composition may be 100 to 500 μm. In the present invention, when the average particle size of the valuable metal recovery composition is within the above range, there is an advantage in being able to manufacture a desired valuable metal alloy in which a Cu coating layer is uniformly formed.

[0108] If the upper limit of the above particle size range is exceeded, there is a problem of low recovery rate because Cu is coated on the surface of the NCM alloy, suppressing the leaching of the NCM metal; if the lower limit of the above particle size range is exceeded, the content of valuable metals decreases and the content of graphite increases, which negatively affects leaching and makes it difficult to secure a uniform composition of the final valuable metal alloy.

[0109] Alternatively, as the particle size decreases, the leaching rate of the metal increases, causing not only NCM but also Cu to be completely leached out, preventing the formation of a Cu coating layer; consequently, it may not be possible to form a high-content and high-purity Cu alloy.

[0110]

[0111] In the present invention, a primary leaching step can be performed by mixing sulfuric acid with a valuable metal recovery composition formed by heat-treating the spent lithium battery for reduction and leaching.

[0112] Throughout the specification of the present invention, the “valuable metal recovery composition” may be referred to as “raw material” or “NCM alloy raw material.”

[0113] The above sulfuric acid concentration may be 1.0 to 3.0 M, and specifically, about 1.5 to 2.5 M. When the sulfuric acid concentration is within the above range, the H concentration in the solution becomes sufficiently high, which promotes the leaching reaction of metal ions, and metal ions such as Cu², Ni², Co², and Mn² can be effectively leached.

[0114] In the present invention, a valuable metal recovery composition can be added at a rate of 50 to 200 g / L per unit volume of sulfuric acid solution, and specifically, at a rate of 50 to 150 g / L or 80 to 120 g / L.

[0115] 1.0 to 1.5 equivalents of sulfuric acid can be mixed based on the NCM alloy included in the above valuable metal recovery composition.

[0116] In the present invention, the first leaching step can be performed at a temperature in the range of 25 to 80°C, specifically at 40 to 60°C.

[0117] In the present invention, the first leaching step can be performed for 1 to 6 hours, specifically for 2 to 4 hours.

[0118] In the present invention, during the first leaching step, a portion of the NCM in the valuable metal recovery composition may not be leached out and may remain as a residue.

[0119] In the present invention, the leaching rate of NCM included in the valuable metal recovery composition may be 30 to 70%, specifically 40 to 60%.

[0120] In the present invention, by performing the first leaching step under the above conditions, there is an advantage of being able to stably form metal ions such as Cu², Ni², Co², and Mn² with less energy.

[0121] Meanwhile, the major metals included in the above valuable metal recovery composition may have different reduction potentials, so their leaching rates may differ.

[0122] Cu 2+ + 2e- = Cu(s), Eo = 0.34

[0123] Ni 2+ + 2e- = Ni(s), E o = -0.25

[0124] Co 2+ + 2e- = Co(s), E o = -0.28

[0125] Mn 2+ + 2e- = Mn(s), E o = -1.18

[0126]

[0127] From the above, Cu 2+ The reduction potential of is the largest, and Ni 2+ , Co 2+ , Mn 2+ When present with, it is most likely to accept electrons first and be reduced to a metal. Conversely, during leaching, Mn 2+ Since the reduction potential of is relatively small, it can be leached first, and next is Ni 2+ and Co 2+ It can be confirmed that it can be leached at a similar point in time.

[0128] When a valuable metal recovery composition (NCM alloy raw material) is introduced within the above range, Ni²⁻, Co²⁻, and Mn²⁻ metal ions are sequentially dissolved according to the reduction potential, and when undissolved (unleaded) NCM alloy raw material remains as a residue, the Cu described later 2+ When additional solution is added, some of the NCM alloy is dissolved as a result, and there is an advantage in being able to form a valuable metal recovery alloy (Cu-coated NCM alloy) with a Cu coating layer.

[0129]

[0130] In the present invention, if the average particle size of the valuable metal recovery composition is 100 μm or more, an oxidation additive may be further mixed in the first leaching step.

[0131] The above oxidation additive may include one or more selected from air, oxygen (O2), or hydrogen peroxide (H2O2).

[0132] When the above oxidation additive is air, it can be supplied continuously at a flow rate of 1.0 to 3 L / min. Here, the air flow rate per unit weight of the valuable metal recovery composition may be 0.01 to 0.03 L / g·min.

[0133]

[0134] When the oxidation additive is oxygen (O2), it can be supplied continuously at a flow rate of 1.0 to 3.0 L / min. Here, the oxygen flow rate per unit weight of the valuable metal recovery composition may be 0.005 to 0.015 L / (g·min).

[0135] When the above oxidation additive is hydrogen peroxide (H2O2), it can be added in an amount of 13 vol% or more of the total volume of the aqueous sulfuric acid solution, specifically in a range of 5 to 30 vol%.

[0136] When the above oxidation additive is added within the above range, there is an advantage in that copper (Cu) in the valuable metal recovery composition, which is the raw material, can be effectively leached out.

[0137] In the present invention, if the input amount of the oxidation additive exceeds the above range, all of the NCM is leached out during the first leaching step, resulting in a shortage of metal capable of providing electrons, and thus Cu 2+ A problem may arise where it is difficult to reduce to Cu(s). In addition, Cu 2+ There is a problem in manufacturing an alloy with a Cu coating layer because the oxidizing agent receives the electrons that should be received.

[0138] After the first leaching step is completed, a second leaching step can be performed by additionally adding an aqueous copper salt solution to further leach out valuable metals.

[0139] In the second leaching step above, the copper salt solution may be mixed in an amount of 1.1 to 1.5 equivalents based on the NCM alloy contained in the remaining residue. Here, the copper salt solution refers to an aqueous solution containing monovalent or divalent copper ions.

[0140] In the present invention, the copper salt aqueous solution may include one or more of copper salts such as copper sulfate (CuSO4), copper nitrate (Cu(NO3)2), copper hydrochloride (CuCl2), and copper carbonate (CuCO3), and specifically, it may be copper sulfate (CuSO4).

[0141] In the present invention, by additionally adding an aqueous copper salt solution as described above, Cu² provided in the aqueous copper salt solution undergoes electron exchange with the metal reactant to Cu 2+ It is desirable to selectively leach metals with a reduction potential lower than that of Cu to form a Cu-concentrated metal alloy, thereby improving the Cu content and purity in the final alloy.

[0142] As explained above, the residual residue refers to the residue that remains in a solid state without being dissolved in the first leaching step.

[0143] The above secondary leaching step can be performed for 0.5 to 3 hours at a temperature in the range of 25 to 80°C.

[0144] In the above second leaching step, the Cu² provided in the copper salt aqueous solution undergoes electron exchange with the metal reactant to Cu 2+ It can play an important role in selectively leaching metals with a reduction potential below that of Cu and forming a metal alloy with a concentrated Cu.

[0145] Cu²⁺ in an aqueous copper salt solution can dissolve metal with low energy through a spontaneous redox reaction with the metal in the reactants.

[0146] Cu 2+ + M→ Cu(s) + M 2+

[0147] The above reaction equation represents the process in which Cu² gains electrons and precipitates as metallic Cu, and the metallic M of the reactant dissolves into ions (M²). By adding an aqueous copper salt solution, the leaching efficiency of Ni², Co², and Mn² can be improved, and at the same time, Cu metal can be precipitated on the surface of the valuable metal recovery composition to form a coating layer.

[0148] The concentration of the above copper salt aqueous solution may be 0.3 to 0.9 M. By satisfying the above range, the concentration of the copper salt aqueous solution allows Cu² to react in balance with the valuable metal recovery composition, thereby enabling stable leaching of Ni², Co², and Mn², and consequently forming a stable Cu coating layer, which has the advantage of being able to form a stable Cu coating layer.

[0149] In the above second leaching step, by reacting at the above temperature and time, there is an advantage in being able to produce a valuable metal recovery alloy with a properly formed Cu coating layer.

[0150]

[0151] In the present invention, the step of separating the valuable metal recovery alloy after the completion of the second leaching may further include a step of tertiary leaching by introducing an aqueous sulfuric acid solution into the separated valuable metal recovery alloy.

[0152] Cu in the secondary leaching solution obtained by solid-liquid separation after the completion of the above secondary leaching 2+ The concentration may be 50 mg / L or less. In the present invention, Cu in the secondary leaching solution 2+ By controlling the concentration within the above range, there is an advantage in being able to recover high concentrations of valuable metals without the need for an additional downstream separation process.

[0153]

[0154] An oxidation additive may be further added during the above third leaching step.

[0155] The above oxidation additive may include one or more selected from oxygen (O2) or hydrogen peroxide (H2O2).

[0156] When the above oxidation additive is oxygen (O2), it can be supplied continuously at a flow rate of 1.0 to 3.0 L / min.

[0157] If the above oxidation additive is hydrogen peroxide (H2O2), it can be added in an amount of 15 vol% or more of the volume of the above sulfuric acid aqueous solution.

[0158] In the present invention, through the third leaching step, Cu 2+ There is an advantage in being able to manufacture valuable metal recovery alloys with higher content and purity.

[0159] Meanwhile, after the third leaching step is completed, solid-liquid separation can be performed to finally produce a Cu-coated valuable metal recovery alloy with a high Cu content.

[0160] Meanwhile, the tertiary leaching solution separated in the above solid-liquid separation can be circulated and introduced into the above secondary leaching step.

[0161] Cu in the tertiary leaching solution obtained by solid-liquid separation after the completion of the above tertiary leaching 2+ The concentration may be 12.0 to 26.0 g / L. In the present invention, Cu in the tertiary leaching solution 2+ It is desirable that the concentration satisfies the above range, thereby preventing the concentration of NCM valuable metals from being diluted when circulated into the secondary leaching step.

[0162]

[0163] In the present invention, by circulating the tertiary leaching solution to the secondary leaching stage, there is an advantage of improving overall production efficiency and economic feasibility.

[0164]

[0165] The embodiments of the present invention will be described in more detail below through examples. However, the following examples are merely preferred embodiments of the present invention, and the present invention is not limited by the following examples.

[0166]

[0167] (Example 1)

[0168] (Preparation of raw materials_Preparation of valuable metal recovery composition (VM))

[0169] Cells, modules, or packs of electric vehicle waste batteries containing a lithium-ion cathode material, a graphite anode material, an aluminum current collector, a separator, an electrolyte, and a copper current collector are prepared. The waste batteries are frozen at a temperature of -30°C or lower and then shredded. Here, the waste batteries are shredded under inert gas conditions using a shredder device so that the longest length between the width and length is 100 mm or less.

[0170] After obtaining a valuable metal recovery composition by the method described above, a reduction process was performed by heat-treating the crushed battery material at 1,300 ℃ under conditions of an oxygen partial pressure of less than 0.5%. After the reduction process, the reduction product was cooled under conditions of a cooling rate of 25 ℃ / min, and then a composition concentrated with NCM alloy was obtained through particle size and magnetic separation.

[0171] The above composition is classified through magnetic separation into a valuable metal recovery composition in which NCM alloy is concentrated and the remaining solids (Cu+Graphite formed alone, not as a Li compound+alloy).

[0172] Here, the valuable metal recovery composition consists of 75-80% NCM alloy, 10% graphite, 5% Cu, and 5-10% Li compound.

[0173] In the above valuable metal recovery composition, the contained Li compounds were selectively leached out using low-concentration sulfuric acid, and the residue contained high-concentration NCM metal and acid-insoluble graphite. This residue was used as a raw material for manufacturing a valuable metal recovery alloy, specifically a Cu-coated valuable metal recovery alloy.

[0174] The average particle size of the above valuable metal recovery composition was set to 100 to 500 μm.

[0175] The content of the above raw materials measured through ICP and C / S analysis is as shown in Table 1 below.

[0176] Elemental LiAlNiCoMnCuC Content (wt%) 0.05~0.3 1.2~5.5 4 2.2~5 9.8 11.6~18.9 11.4~19.1 4.7~15.1 7.1~13.3

[0177] (1st leaching)

[0178] 100g of the prepared raw material, the valuable metal recovery composition, was added to 1L of a 2M aqueous sulfuric acid solution and reacted at a temperature of 60℃ for 4 hours while stirring with a stirring member.

[0179] At this time, 1.3 equivalents of the sulfuric acid were added based on the NCM alloy in the valuable metal recovery composition.

[0180] Here, air was continuously supplied as an oxidation additive at a flow rate of 2 L / min.

[0181] After the first leaching was completed, the leaching rate of the NCM alloy in the valuable metal recovery composition was 62.6%.

[0182] The leaching rate of the above NCM alloy was calculated using the following formula after separating the residue and measuring the metal ion concentration of the leaching solution using ICP-OES.

[0183] Leaching rate (%) = (Concentration of NCM metal ions dissolved in the leachate after leaching (g / L) * Volume of leachate (g)) / Weight of NCM in the valuable metal recovery composition (g) * 100

[0184] (Secondary leaching)

[0185] After the first leaching was completed, an aqueous copper salt solution with a concentration of 0.5 M was added, and the mixture was reacted at 60°C for 2 hours to form a valuable metal recovery alloy (Cu-coated - NCM alloy).

[0186] Here, 1.5 equivalents of the copper salt aqueous solution were added based on the NCM alloy in the primary leaching residue.

[0187] (High-value separation)

[0188] After the second leaching was completed, the valuable metal recovery alloy was separated using a filter.

[0189]

[0190] (Comparative Example 1)

[0191] A valuable metal recovery alloy was prepared in the same manner as in Example 1, except that the second leaching step was not performed during the first leaching step. A valuable metal recovery alloy was prepared in the same manner as in Example 1 by continuously supplying air as an oxidizing additive at a flow rate of 2 L / min. When air is used as an oxidizing agent in the first leaching step, the oxidizing power is not high, so Cu is used to locally dissolve Cu and replace it with the NCM alloy. 2+ It was confirmed that it is difficult to manufacture a Cu-coated valuable metal recovery alloy without the additional addition of an aqueous copper salt solution, as it is difficult to find.

[0192]

[0193] (Comparative Example 2)

[0194] A valuable metal recovery alloy was prepared using the same method as in Example 1, except that O2 was continuously supplied as an oxidation additive at a flow rate of 2 L / min during the first leaching step. When leaching is performed by adding an excess amount of O2, which has high oxidizing power, during the first leaching step, all NCM metals in the solution are dissolved, leaving no metal to substitute; therefore, Cu 2+ It was confirmed that it is difficult to manufacture a Cu-coated valuable metal recovery alloy even with additional input.

[0195]

[0196] (Evaluation Example 1) SEM Analysis Results

[0197] SEM analysis was performed on the valuable metal recovery alloys prepared according to Example 1 and Comparative Example 1, and the SEM analysis images are shown in Figures 3 and 4, respectively.

[0198] Referring to Fig. 3 (A), it can be seen that copper (Cu) located on the surface of the valuable metal recovery alloy prepared according to Example 1 is visible, whereas copper (Cu) is difficult to see on the surface of the valuable metal recovery alloy prepared according to Comparative Example 1.

[0199]

[0200] (Evaluation Example 2) Cross-sectional SEM-FIB and EPMA Analysis Results

[0201] Cross-sections of the valuable metal recovery alloys prepared according to Example 1 and Comparative Example 1 were cut and SEM-FIB analysis was performed, and the analysis results are shown in Figures 5 and 6, respectively.

[0202] In addition, cross-sections of the valuable metal recovery alloys prepared according to Example 1 and Comparative Example 1 were cut and EPMA analysis was performed, and the analysis results are shown in Figs. 7 and 9, respectively.

[0203] In addition, EPMA analysis was performed on the surface of the valuable metal recovery alloy prepared according to Example 1 above, and the analysis results are shown in Figure 8.

[0204] Referring to Examples Figs. 5, 7, and 8, it can be seen that the valuable metal recovery alloy manufactured according to Example 1 of the present invention comprises a Cu coating layer and an NCM core portion, and includes an intermediate layer with a void channel formed between the coating layer and the core portion.

[0205] Referring to Fig. 5, the average thickness of the coating layer is 5 to 20 μm, and an intermediate layer with a void channel having a length of 10 μm or more can be seen.

[0206] In addition, the average particle size of the valuable metal recovery alloy prepared according to Example 1 is about 150 μm, and it can be confirmed that a uniform Cu coating layer is formed over the entire surface of the particles.

[0207] Raw Material Final Alloy Average Particle Size (㎛) Ni Content (wt%) Mn Content (wt%) Co Content (wt%) Cu Content (wt%) Average Particle Size (㎛) Cu Content (wt%) Cu Coating Layer Thickness (㎛) Example 1 100~200 42.2~59.8 11.4~19.1 11.6~18.9 4.7~15.1 120~250 12.7~25.3 2~10 Comparative Example 1 100~200 42.2~59.8 11.4~19.1 11.6~18.9 4.7~15.1 85~190 5.6~16.3 - Comparative Example 2 100~200 42.2~59.8 11.4~19.1 11.6~18.9 4.7~15.1 -

[0208] Referring to Examples Figs. 6 and 9, it can be seen that the valuable metal recovery alloy prepared according to Comparative Example 1 of the present invention does not have a Cu coating layer formed.

[0209] The present invention is not limited to the above embodiments and can be manufactured in various different forms, and those skilled in the art will understand that the invention can be implemented in other specific forms without changing the technical concept or essential features of the invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

1. Valuable metal recovery alloy core part; A porous intermediate layer located on the core portion; and A Cu-containing coating layer located on at least a portion of the surface of the porous intermediate layer; comprising Precious metal recovery alloy.

2. In Paragraph 1, The above Cu-containing coating layer is coated on an area of ​​10% or more of the surface area of ​​the above porous intermediate layer, Precious metal recovery alloy.

3. In Paragraph 1, The above porous intermediate layer comprises one or more pore channels having a length of 10㎛ or more, Precious metal recovery alloy.

4. In Paragraph 1, The average thickness of the above porous intermediate layer is 3㎛ or more, Precious metal recovery alloy.

5. In Paragraph 1, Based on the cross-section of the above-mentioned valuable metal recovery alloy, the area of ​​voids included in the intermediate layer based on the area of ​​the above-mentioned porous intermediate layer is 40% or more, Precious metal recovery alloy.

6. In Paragraph 1, The thickness of the coating layer is 1 to 50 μm, Precious metal recovery alloy.

7. In Paragraph 1, The average particle size of the above valuable metal recovery alloy is 100 to 500 μm, Precious metal recovery alloy.

8. In Paragraph 1, The copper (Cu) content included in the above valuable metal recovery alloy is 12.0 to 40.0 wt%, Precious metal recovery alloy.

9. In Paragraph 1, The above Cu-containing coating layer is coated on an area of ​​10% or more of the surface area of ​​the above porous intermediate layer, Precious metal recovery alloy.

10. In Paragraph 9, The above Cu-containing coating layer is coated over the entire surface area of ​​the porous intermediate layer. Precious metal recovery alloy.

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