Valuable metal recovery composition and valuable metal recovery method

Abstract

The present disclosure relates to a valuable metal recovery composition and a method for producing same. The valuable metal recovery composition comprises a reactant having a flake shape, wherein the reactant includes a base material, and an alloy is partially melted and disposed on at least a portion of the surface of the base material.

Description

Composition for recovering valuable metals and method for recovering valuable metals

[0001] The invention relates to waste batteries, and more specifically to a composition for recovering valuable metals recovered from waste battery recycling, a reactant for a method of recovering the same, a valuable metal crushed material, and a method for recovering valuable metals.

[0002] The present invention claims priority based on Korean Patent Application No. 10-2024-0188109 filed on December 17, 2024, the entire contents of said application 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-purity 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] Generally, as the particle size of the raw material increases, the efficiency of the leaching process decreases, so it is important to obtain fine particles; however, since the size and shape of the raw material affect the screening process, it is necessary to control the optimal particle size and shape.

[0011] According to one embodiment of the present invention, a valuable metal recovery composition provides a composition comprising an alloy capable of maximizing the efficiency of wet leaching and the efficiency in the screening process.

[0012] According to another embodiment of the present invention, a method for recovering valuable metals provides a method for producing a valuable metal recovery composition having the aforementioned advantages.

[0013] According to one embodiment of the present invention, a valuable metal recovery composition comprises a reactant having a flake shape, wherein the reactant comprises a base material, and an alloy may be partially melted and disposed on at least a portion of the surface of the base material. In one embodiment, the base material may comprise at least one of a lithium compound and graphite.

[0014] In one embodiment, the alloy may include nickel, cobalt, manganese, copper, iron, and combinations thereof. In one embodiment, the flake shape may be characterized in that at least one of the angles where the two outer lines of the reactants meet is 90° or less.

[0015] In one embodiment, the particle size of the reactant may satisfy a range of 250 to 1000 μm. In one embodiment, the particle size of the alloy may be 10 μm or less. In one embodiment, based on 100% of the surface of the base material, the ratio of the alloy may be 5 to 95%.

[0016] According to another embodiment of the present invention, a method for recovering valuable metals comprises the steps of preparing a battery and performing high-temperature heat treatment on the battery or on a battery crushed material, wherein the high-temperature heat treatment step may be performed at a temperature at which at least a portion of the battery or on the battery crushed material begins to be reduced.

[0017] In one embodiment, the temperature at which reduction begins may be 700 to 1,250°C. In one embodiment, the high-temperature heat treatment step may be performed at a heating rate of 3°C or more per minute.

[0018] In one embodiment, the high-temperature heat treatment step may be performed in a temperature range satisfying the following Equation 1.

[0019] <Equation 1>

[0020]

[0021] *19<Equation 1>

[0022] 700 ≤ T ≤ (1000 + 250) × exp((0.0001 × [Cu]) + (-0.007 × [Al]))

[0023] (In Equation 1, [Al] is the content of Al (weight%) contained in the battery or battery crush, [Cu] is the content of Cu (weight%) contained in the crush, and the unit of the heat treatment condition is °C)

[0024] In one embodiment, the high-temperature heat treatment step may be performed under conditions where O2 is less than 5% by volume fraction. 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 less than 1% by volume fraction. In one embodiment, the step of preparing the battery may include the step of crushing the battery.

[0025] According to one embodiment of the present invention, a valuable metal recovery composition comprises a reactant having a flake shape, and by partially melting and disposing of the alloy in at least a portion of the surface of the base material, it is possible to provide an alloy reactant that can maximize the efficiency of wet leaching and the efficiency in the screening process.

[0026] According to another embodiment of the present invention, a method for recovering valuable metals can provide an alloy reactant that can maximize the efficiency of wet leaching and the efficiency in the screening process by performing a high-temperature heat treatment step at a temperature at which a portion of the crushed material begins to be reduced.

[0027] Figure 1 shows an SEM image of a valuable metal recovery composition according to one embodiment of the present invention.

[0028] FIG. 2 shows the morphological features of a reactant having a flake shape according to one embodiment of the present invention.

[0029] FIG. 3 illustrates a feature in which an alloy is disposed on the surface of a reactant having a flake shape, according to one embodiment of the present invention.

[0030] Figure 4 is an SEM image of a valuable metal recovery composition according to a comparative example of the present invention.

[0031] Figures 5 and 6 are SEM images of a valuable metal recovery composition according to a comparative example of the present invention.

[0032] Figure 7 shows the shape of a reactant prepared according to a comparative example of the present invention.

[0033] FIG. 8 shows a reaction product prepared according to an embodiment of the present invention.

[0034] 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.

[0035] 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.

[0036] When it is stated that one part is "above" or "on" another part, it may be directly above or on the other part, or other parts may be involved in between. In contrast, when it is stated that one part is "directly above" another part, no other parts are interposed in between.

[0037] 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.

[0038] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and are not intended to limit the present invention, and the present invention is defined only by the scope of the claims set forth below.

[0039] According to one embodiment of the present invention, a valuable metal recovery composition comprises a reactant having a flake shape, and may be formed by performing a high-temperature reduction heat treatment process on a battery or a crushed battery material obtained by crushing said battery. Specifically, the valuable metal recovery composition may comprise a plurality of the reactants having the flake shape.

[0040] The reactant having the flake shape described above may partially maintain the shape of the current collector within the battery or battery crush by performing the high-temperature reduction heat treatment process on the battery or battery crush at the temperature at which lithium begins to be reduced. Since the valuable metal recovery composition includes the reactant having the flake shape, separation from graphite during particle size and magnetic separation in the subsequent separation process is more advantageous, which has excellent benefits for improving the recovery rate of valuable metals. Specifically, if the reactant does not have a flake shape, fine metal particles are formed on the surface of the graphite; consequently, it is difficult to physically separate the metal particles from the graphite surface, and there is a problem in that separation is difficult even by methods such as particle size separation because the size difference with the graphite is not significant. Furthermore, if the metal particles are attached to the graphite surface, they become magnetic, which causes a problem of lowering the recovery rate of valuable metals in the subsequent magnetic separation stage.

[0041] The flake shape may refer to an irregular shape. Specifically, the irregular shape may refer to a shape including a pointed region. In one embodiment, the flake shape may be characterized in that at least one of the angles where two outlines of the reactant meet is 90° or less. For example, when a plurality of outlines are drawn on the outer surface of the reactant in an SEM image of the reactant, the shape may be characterized in that there are multiple regions where the angle between two outlines among the plurality of outlines is 90° or less.

[0042] In one embodiment, the reactant having the flake shape may include a base material and an alloy disposed on at least a portion of the surface of the base material. Specifically, the reactant having the flake shape may be such that the alloy is partially melted on the base material and disposed on at least a portion of the surface of the base material.

[0043] The above base material may include at least one of a lithium compound and graphite. Specifically, the above base material is formed by high-temperature heat treatment of a battery or battery crushed material, and is formed by reducing at least a portion of the battery or battery crushed material, for example, a component such as a current collector may be arranged while maintaining a partial shape.

[0044] Specifically, the base material may include a compound in which aluminum, which is a major component of the current collector, forms an oxide with lithium, and may also include graphite constituting the negative electrode material. By including at least one of the lithium compound and graphite in the base material, when separating valuable metals in a subsequent process, the components excluding valuable metals can be easily separated, thereby increasing the recovery rate of valuable metals.

[0045] The above alloy may be formed by partially melting a metallic material constituting the positive electrode active material during a high-temperature heat treatment process of a battery or battery crushed material, and then coating and placing it on the base material. For example, the alloy may include metallic materials such as nickel, cobalt, manganese, copper, or iron as the material constituting the positive electrode active material. Specifically, the alloy may be formed by partially melting and alloying a metal such as nickel or copper. By partially melting and placing the alloy on at least a portion of the base material, the magnetic alloy can be easily separated during a subsequent sorting process, thereby increasing the recovery rate of valuable metals.

[0046] In one embodiment, the particle size of the reactant may satisfy a range of 100 to 1000 μm. Specifically, the reactant may include i) a reactant having a first particle size of 100 to 150 μm, ii) a reactant having a second particle size of 150 to 250 μm, iii) a reactant having a third particle size of 250 to 500 μm, and iv) a reactant having a fourth particle size of 500 to 1000 μm. The particle size of the reactant may refer to an average particle size (D50).

[0047] In one embodiment, based on 100% of the reactants, the reactant having the first particle size may be included in an amount of 8 to 19%, the reactant having the second particle size in an amount of 12 to 25%, the reactant having the third particle size in an amount of 30 to 38%, and the reactant having the fourth particle size in an amount of remainder. The % may be based on volume.

[0048] When the particle size of the aforementioned reactant is formed as fine particles of less than 100 μm, there is a problem in that separation from graphite is not easy. However, when the particle size of the aforementioned reactant is formed as large as 100 μm or more, the particle size of the metal droplet formed on the flake is much finer than that of the flake, so there is an advantage of high leaching efficiency.

[0049] Specifically, satisfying the aforementioned range for the particle size of the reactant provides the advantage of facilitating leaching and screening processes in subsequent steps. If the particle size of the reactant is excessively coarse, the amount of valuable magnetic metal within the flake is relatively small, leading to a problem where the metal recovery rate decreases even if magnetism is present. If the particle size of the reactant is excessively small, the structure of the crushed material collapses, forming fine particles akin to dust, resulting in inferior screening and leaching efficiency for magnetic separation.

[0050] In one embodiment, the particle size of the alloy may be 250 μm or less. Specifically, the particle size of the alloy may satisfy a range of 1 to 180 μm. By satisfying the aforementioned range for the particle size of the alloy, there is an advantage of excellent leaching and screening efficiency. If the particle size of the alloy is excessively coarse, there is a problem in that the leaching of alloy particles is not easy during leaching.

[0051] In one embodiment, the ratio of the alloy may be 5 to 95% based on 100% of the surface of the base material. Specifically, based on 100% of the surface of the base material, the ratio of the alloy partially melted and coated on the surface of the base material may be 13 to 84%. By forming the fine alloy on the surface of the base material (FLAKE) at the aforementioned ratio, there is an advantage of a high leaching rate of valuable metals. The ratio of the alloy may refer to the ratio of either the upper surface or the lower surface of the base material.

[0052] In one embodiment, the proportion of the alloy on the surface with a higher proportion of the alloy among the upper or lower surfaces of the base material may be 70% or more based on 100% of the surface of the base material. Specifically, the proportion of the alloy may be 70% to 95%, specifically 75% to 95%.

[0053] If the above ratio deviates from the lower limit of the aforementioned range, the reduction process cannot be performed smoothly, and the alloy is not partially melted on the base material, resulting in a problem where the recovery rate of valuable metals is reduced.

[0054] In one embodiment, the shape of the partially molten alloy may have a spherical shape. Specifically, the shape of the alloy is formed by melting the oxide anode material after reduction, and at this time, it may have a spherical shape with the lowest surface energy. Specifically, the shape of the alloy may manifest as a spherical shape with the lowest surface area.

[0055] According to another embodiment of the present invention, a method for recovering valuable metals comprises the steps of preparing a battery and performing high-temperature heat treatment on the battery or on a battery crushed from the battery. 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 crush begins to be reduced, a valuable metal recovery composition may 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. A detailed description of the valuable metal recovery composition may refer to the foregoing to the extent that it is not contradictory.

[0056] 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.

[0057] 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.

[0058] In one embodiment, the step of pre-treating the battery may include a 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.

[0059] 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.

[0060] 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.

[0061] 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 1.0 V or lower, the low-temperature treatment step may be performed on the battery at a temperature of 0°C or lower. More specifically, when the voltage of the battery is 1.5 to 2.0 V, the battery may be low-temperature treated at a temperature of -15°C or lower. More specifically, when the voltage of the battery is approximately 2.5 V, the battery may be low-temperature treated at a temperature of -30°C or lower. More specifically, when the voltage of the battery is 3 to 3.5 V, the battery may be low-temperature treated at a temperature of -50°C or lower.

[0062] 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.

[0063] 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 2 V to 3 V, is reduced to near 0 V. 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.

[0064] 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 0 V, 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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 ℃, which is the average vaporization temperature of the electrolyte, and safety issues such as fire may occur.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] If the aforementioned heating rate range exceeds the lower limit of the aforementioned range, smooth nucleation does not occur, and growth becomes relatively easy, leading to the problem of metal particles becoming coarse; the formation of such coarse alloys results in a decrease in the leaching rate in subsequent processes. If the aforementioned heating rate range exceeds the upper limit of the aforementioned range, the distortion of the current collector that holds the flake structure accelerates, forming relatively fine flakes and causing a problem of reduced separation efficiency from carbon.

[0078] 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.

[0079] In one embodiment, the high-temperature heat treatment step can be performed in a temperature range satisfying the following Equation 1.

[0080] <Equation 1>

[0081] 700 ≤T ≤ (1000 + 250) × exp((0.0001 × [Cu]) + (-0.007 × [Al]))

[0082] (In Equation 1, [Al] is the content of Al (weight%) contained in the battery or battery crush, [Cu] is the content of Cu (weight%) contained in the crush, and the unit of temperature is °C)

[0083]

[0084] T in Equation 1 above may be an indicator regarding the formation of reactants having a flake shape and partial melting of the alloy. Since changes in physical phenomena of the structure occur at relatively higher temperatures for copper (Cu) compared to aluminum (Al), the heat treatment temperature increases as the copper content increases. Conversely, since an increase in the aluminum content causes a relative decrease in the copper content, the heat treatment temperature must be lowered. Based on this, the relationship between the copper and aluminum content was derived as Equation 1.

[0085] By satisfying the aforementioned range of Equation 1, a valuable metal recovery composition in which the alloy is partially melted in a reactant having a flake shape can be easily implemented, thereby increasing the leaching and separation efficiency of valuable metals in subsequent processes.

[0086] At this time, in Formula 1 above, the aluminum content may be 1 weight% to 75 weight%, specifically 73 weight% or less, and the copper content may be 70 weight% or less. By satisfying the aforementioned ranges for the aluminum content and the copper content in the battery or battery crush, it may be possible to realize a composition in which the alloy is partially melted in a reactant having a flake shape.

[0087] If the above Equation 1 exceeds the upper limit of the aforementioned range, there is a problem in that the formation of flakes collapses excessively and becomes fine. If the above Equation 1 exceeds the lower limit of the aforementioned range, there is a problem in that the shape of the coarse crushed material is maintained and the alloy phase is not formed.

[0088]

[0089] Preferred embodiments and comparative examples of the present invention are described below. However, the following examples are merely preferred embodiments of the present invention, and the present invention is not limited to the following examples.

[0090]

[0091] <Experimental Example>

[0092] Example 1

[0093] <Battery Preparation Step>

[0094] A cell-based 3.6 V battery was prepared for an NCM622 lithium-ion battery having approximately 4.2 V when the SOC is 100%. The battery was discharged to 0.5 V or lower within 2 hours by applying a current of 5 A to the initial battery.

[0095]

[0096] After *87, the above battery was subjected to cryogenic treatment at -60°C for 24 hours.

[0097]

[0098] <Battery shredding step>

[0099] The above battery was shredded using a 2-axis 2-stage shredder to a particle size range of 5 to 80 mm. The shredded battery material had a layered structure in which the positive electrode, negative electrode, and separator were stacked in sequence, and the layered structure was stacked in at least one layer, and the size of the battery shred was 100 mm or less. The size of the battery shred refers to the length based on the major axis among the width, length, and height of the battery shred. The shredding was completed within 5 minutes for the module and within 3 minutes for the cell.

[0100]

[0101] <Step of reducing the battery to high temperature>

[0102] The above battery was reduced to a high temperature in a high-temperature reduction furnace, and the process was carried out at a temperature at which at least a portion of the battery, for example, battery crushed material, begins to be reduced. Specifically, the battery was heated in a high-temperature reduction furnace at a heating rate of 3°C or more per minute, and after reaching 1,050°C, dry heat treatment was maintained for 2 hours. At this time, the process was carried out in an atmosphere of less than 5% O2 and less than 1% Ar. The aforementioned heat treatment conditions were performed at a temperature above which deformation is applied to the positive current collector, within a temperature range where some of the metal, such as copper, partially melts, and within a range where lithium is not lost through vaporization.

[0103] Figure 1 shows an SEM image of a valuable metal recovery composition according to one embodiment of the present invention.

[0104] Referring to FIG. 1, according to one embodiment of the present invention, a valuable metal recovery composition is formed with a plurality of flake-shaped reactants having a size of 100 to 1000 μm. It was confirmed that the flake reactants have a shape in which fine metal alloy particles with an average size of about 10 μm or less are arranged on the surface of graphite. Since the metal alloy has magnetism, the valuable metal recovery composition can be easily separated by magnetic force.

[0105] FIG. 2 shows the morphological features of a reactant having a flake shape according to one embodiment of the present invention.

[0106] Referring to FIG. 2, a reactant having a flake shape in a valuable metal recovery composition according to one embodiment of the present invention is characterized in that at least one of the angles where two outlines meet is 90° or less.

[0107] FIG. 3 illustrates a feature in which an alloy is disposed on the surface of a reactant having a flake shape, according to one embodiment of the present invention.

[0108] Referring to Fig. 3, it can be seen that the alloy is partially melted and placed on the base material of the reactant.

[0109]

[0110] Comparative Example 1 - Below lower temperature limit

[0111] The process was carried out in the same manner as Example 1, except that the heat treatment temperature was performed at a low temperature of 700 ℃ or lower during the step of reducing the battery to a high temperature.

[0112] Figure 4 is a digital camera photograph of a valuable metal recovery composition according to a comparative example of the present invention.

[0113] Referring to FIG. 4, it was confirmed that the valuable metal recovery composition according to Comparative Example 1 of the present invention contains a plurality of coarse reactants. Specifically, it was confirmed that because the coarse reactants in the valuable metal recovery composition have large particle sizes and are hard, they require an additional milling process and the amount of reduction of the alloy is excessively low.

[0114]

[0115] Comparative Example 2 - Exceeding Temperature Upper Limit

[0116] In the step of reducing the battery to a high temperature, the process was carried out in the same manner as Example 1, except that the heat treatment was performed at a high temperature of 1300 ℃.

[0117] Figures 5 and 6 are digital camera photographs of a valuable metal recovery composition according to a comparative example of the present invention.

[0118] Referring to FIGS. 5 and FIGS. 6, FIGS. 5 shows fine reactants and FIGS. 6 shows coarse reactants. It can be seen that the valuable metal recovery composition according to Comparative Example 2 of the present invention contains a large amount of coarse alloy, but it was also confirmed that as the structure of the crushed material collapses overall, a large amount of fine reactants similar to dust are also included.

[0119]

[0120] Comparative Example 3 - Exceeding the upper limit of the heating rate

[0121] The procedure was performed in the same manner as Example 1, except that the heating rate during the step of reducing the battery to a high temperature was 30°C per minute. When the heating rate was excessive, the formation of fine flakes smaller than 100 μm was confirmed.

[0122] Figure 7 shows the shape of a reactant prepared according to a comparative example of the present invention.

[0123] Referring to Fig. 7, it can be seen that fine flakes of less than 100 μm are formed.

[0124]

[0125] Comparative Example 4 - Heating rate below lower limit

[0126] The process was carried out in the same manner as Example 1, except that the heating rate during the step of reducing the battery to a high temperature was 1°C per minute. When the heating rate was lower than the lower limit, the formation of very coarse alloy droplets was confirmed, and the formation of such coarse droplets causes a decrease in efficiency in the subsequent leaching process.

[0127]

[0128] Table 1 below shows the particle size of the reactants, the particle size of the alloy, and the alloy coating ratio in the valuable metal recovery composition produced when the conditions in the high-temperature reduction step are controlled.

[0129] The reactant particle size, alloy particle size, and alloy coating ratio in Table 1 below were measured by the following method.

[0130] Reactant particle size: The above reactant particle size was selected by targeting five of the plurality of reactants included in the valuable metal recovery composition and sieving them with a certain mesh, specifically 100 to 150 μm, 150 to 250 μm, 250 to 500 μm, and 500 to 1000 μm.

[0131] Alloy particle size: The alloy particle size was measured by SEM analysis of the average particle size of 10 alloys placed on the surface of the reactant.

[0132] Alloy coating ratio: Five of the multiple reactants in the valuable metal recovery composition were targeted, and the ratio of alloy coating based on 100% of the reactant surface was measured using Image J, an image analysis software.

[0133] Figure 8 shows a reaction product prepared according to Example 1 of the present invention.

[0134] Classification High-temperature reduction step Condition Reactant temperature [°C] Heating rate [°C / min] Formula Reactant particle size [㎛] Alloy particle size [㎛] Alloy coating ratio [%] Example 1 1,025 3 Satisfied 100~1000 Satisfied 10~250 Satisfied 85% Satisfied Comparative Example 1 6,503 Unsatisfied 2000~5000 Unsatisfied Extremely fine formation Unsatisfied Less than 5% Unsatisfied Comparative Example 2 1,300 3 Unsatisfied Fine particles less than 100 Unsatisfied Coarse particles 500~1000 Unsatisfied 500~1000 Unsatisfied 80% Satisfied Comparative Example 3 1,025 30 Unsatisfied Satisfied Fine particles less than 100 Unsatisfied <20 Satisfied 60% Satisfied Comparative Example 4 1,025 1 Unsatisfied Satisfied 200~1000 Unsatisfied 200~1000 Unsatisfied 70% Satisfied

[0135] Referring to Table 1 and Figure 8 above, the optimal size of the generated reactant is 100 to 1000 μm, the optimal range for the alloy size is 10 to 250 μm, and the alloy coating ratio is high, with the proportion of the area with a higher alloy ratio between the front and back sides of the reactant being 60% or higher. Specifically, in the case of Example 1, it was confirmed that the aforementioned reactant particle size, alloy particle size, and alloy coating ratio were formed within an appropriate range. In contrast, in Comparative Example 1, it was confirmed that the particle size of the reactant was excessively large due to the low temperature itself. In Comparative Example 2, it was confirmed that fine reactants and coarse reactants were formed by grinding due to the excessively high temperature. In this case, the coarse reactants have a problem of a low leaching rate during leaching.

[0136] Comparative Example 3 confirmed that the heating rate was excessively fast, resulting in the formation of fine reactants. While these fine reactants are excellent in terms of leaching efficiency, they have a problem of being inferior in terms of separation efficiency. Specifically, the fine reactants have a problem in that magnetic separation is not easy. Comparative Example 4 confirmed that when the heating rate is excessively slow, the size of the reactants is relatively large, and the size of the formed alloy is also large. The reactants formed in this way have a problem in that they are not effective in terms of leaching efficiency and separation efficiency.

[0137]

[0138] <Evaluation Example>

[0139] Table 2 below shows the results of analyzing the leaching rates of valuable metals Ni, Co, and Mn and the separation efficiency after magnetic separation for the examples and comparative examples of Table 1 above. In Table 2 below, the leaching rates and separation efficiency were measured by the following method.

[0140] Leaching rate: The leaching rate was calculated by measuring the content of each element in the leaching solution through ICP analysis after leaching the reactants in an aqueous solution of 2 M sulfuric acid for 12 hours and conducting leaching experiments for Ni, Co, and Mn.

[0141] Separation efficiency: The separation efficiency was determined by dry particle size separation of the reactants using sieves of 1000–500㎛, 500–250㎛, 250–150㎛, and 150–100㎛, and by magnetic separation using a magnetic separation device with a magnetic strength of 2000 Gauss, and the ratio of the metal alloy after separation to before separation was confirmed.

[0142] Classification Leaching Rate [%] Separation Efficiency [%] Overall Recovery Rate [%] Remarks NiCoMn Magnetic Material (Alloy) Non-magnetic Material (Graphite) NiCoMn Evaluation Opinion Example 1 5 2 4 9 4 8 8 5% 15% 5 3 4 8 4 8 Optimal Comparative Example 1 Leaching Impossible Leaching Impossible Leaching Impossible Separation Impossible --- Leaching Impossible Separation Impossible Comparative Example 2 3 9 4 1 3 9 9 2 8 3 6 3 8 3 6 Low Leaching Rate High Separation Efficiency Comparative Example 3 5 8 5 2 5 2 7 0 3 0 4 6 4 1 4 2 High Leaching Rate Low Separation Efficiency Comparative Example 4 5 0 4 3 4 6 7 7 2 3 3 9 3 3 5 Low Leaching Rate Low Separation Efficiency

[0143] Looking at Table 2 above, it was confirmed through Example 1, Comparative Example 1, and Comparative Example 2 that while the magnetic separation efficiency is excellent for reactants containing large-particle alloys heat-treated at low temperatures, the leaching efficiency is low when leaching is performed in a subsequent process. In the case of reactants containing small-particle alloys, there is a problem in that it is difficult to separate the graphite of the cathode material from the reduced anode material when magnetic separation is performed. Specifically, in the case of the reactants containing small-particle alloys, the non-magnetic graphite becomes magnetic, and the inflow of graphite increases during magnetic separation. This is because ultrafine metal alloys of less than 10 μm are attached to the surface of graphite within 30 μm, causing partial magnetism. Metal alloys formed as ultrafine particles on the surface of graphite in this way are not easily separated by general separation processes and must be melted through a wet smelting process, which presents a problem requiring additional processes.

[0144] In addition, it was confirmed that in the case of Comparative Example 3, the leaching rate was excellent but the separation efficiency was inferior, and in the case of Comparative Example 4, both the leaching rate and the separation efficiency were low. As such, through Example 1 and Comparative Examples 1 to 4, it can be confirmed that when the size of the reactants, the size of the alloy within the reactants, and the coating ratio of the alloy within the reactants are controlled within the range of the present invention, the recovery rate of valuable metals is excellent.

[0145]

[0146] Although preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concepts defined in the following claims are also included within the scope of the present invention.

Claims

1. A valuable metal recovery composition comprising a reactant having a flake shape, The above reactant includes a base material, and A valuable metal recovery composition in which an alloy is partially melted and disposed in at least a portion of the surface of the above-mentioned base material.

2. In Paragraph 1, The above base material is a valuable metal recovery composition comprising at least one of a lithium compound and graphite.

3. In Paragraph 1, The above alloy is a valuable metal recovery composition comprising nickel, cobalt, manganese, copper, iron, and combinations thereof.

4. In Paragraph 1, A valuable metal recovery composition characterized in that the flake shape has at least one angle where the two outer lines of the reactants meet is 90° or less.

5. In Paragraph 1, A valuable metal recovery composition in which the particle size of the above-mentioned reactant satisfies the range of 100 to 1000 μm.

6. In Paragraph 1, A valuable metal recovery composition having a particle size of 250 μm or less of the alloy.

7. In Paragraph 1, Based on 100% of the surface of the above base material, A valuable metal recovery composition in which the ratio of the above alloy is 5 to 95%.

8. Step for preparing the battery; and The method includes the step of high-temperature heat treatment of the battery or the battery crushed from the battery, A method for recovering valuable metals in which the high-temperature heat treatment step is performed at a temperature at which at least a portion of the battery or the battery crushed material begins to be reduced.

9. In Paragraph 8, A method for recovering valuable metals in which the temperature at which reduction begins is 700 to 1,250 ℃.

10. In Paragraph 8, A method for recovering valuable metals in which the above high-temperature heat treatment step is performed at a heating rate of 3°C or more per minute.

11. In Paragraph 8, A method for recovering valuable metals in which the above high-temperature heat treatment step is performed in a temperature range satisfying the following Equation 1. <Equation 1> 700 ≤ T ≤ (1000 + 250) × exp((0.0001 × [Cu]) + (-0.007 × [Al])) (In Equation 1, [Al] is the content of Al (weight%) contained in the battery or battery crush, [Cu] is the content of Cu (weight%) contained in the crush, and the unit of temperature is °C) 12. In Paragraph 8, A method for recovering valuable metals in which the above high-temperature heat treatment step is performed under conditions where O2 is less than 5% by volume fraction.

13. In Paragraph 8, The above high-temperature heat treatment step is performed in an atmosphere containing an inert gas, and A method for recovering valuable metals performed under conditions where the above-mentioned inert gas is less than 1% by volume fraction.

14. In Paragraph 8, A method for recovering valuable metals, comprising the step of preparing the battery and the step of crushing the battery.

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