Valuable metal recovery composition and method of recovering valuable metal

Abstract

The present invention relates to a valuable metal recovery composition and a method of recovering a valuable metal. The valuable metal recovery composition comprises: a valuable metal recovery alloy including a carbon layer; and a lithium compound, wherein the carbon layer is disposed on at least portions of the surface and inside of the valuable metal recovery alloy, and the content of carbon (C) in the carbon layer is at least 60 wt% with respect to 100 wt% of the carbon layer.

Description

Composition for recovering valuable metals and method for recovering valuable metals

[0001] The present invention relates to a waste battery, a composition for recovering valuable metals from waste batteries, and a method for recovering valuable metals.

[0002] As global demand for electric vehicles grows, the disposal of waste batteries generated from these vehicles is emerging as a social issue. Lithium secondary batteries, the primary raw material for these waste batteries, contain organic solvents, explosive materials, and heavy metals such as nickel, cobalt, manganese, and iron. However, nickel, cobalt, manganese, and lithium are valuable metals with high scarcity value. Therefore, the recovery and recycling processes for discarded lithium secondary batteries are emerging as a key research area.

[0003] Specifically, a lithium secondary battery is mainly composed of copper and aluminum used as a current collector, Li, Ni, Co, Mn-containing oxides constituting a positive electrode material, and graphite used as an anode material, and includes a separator separating the positive electrode material and the negative electrode material, and an electrolyte injected into the separator. The solvent used as a solvent and salt constituting the electrolyte is mainly a mixture of carbonate organic substances such as ethylene carbonate and propylene carbonate, and for example, LiPF6 is used.

[0004] In this way, lithium secondary batteries are composed of heavy metal materials such as Ni-Co-Mn-Fe, carbon, and other electrolyte materials, among which Ni, Co, Mn, and Li are valuable as precious metals.

[0005] Recycling for battery raw material recovery typically involves battery disassembly, discharging, crushing, heat treatment, recovery, and wet processes to recover valuable metals. During this process, saltwater discharging is performed, and substances such as sodium, potassium, magnesium, calcium, and chloride (Ca) that enter the recovered raw material are included as impurities.

[0006] After heat treatment, the recovered material forms different products depending on the heat treatment temperature. When heat treated at a temperature below 600 ℃, it is called black powder and is a powder form in which the oxide of Ni-Co-Mn-Li and carbon of the negative electrode material are mixed. Since Al and Cu are removed in advance, they may be included in extremely small amounts.

[0007] When the above black powder is heat-treated at a high temperature of 1,000°C or higher, the metal oxide is reduced and alloyed by the carbon of the negative electrode material, and a black alloy containing the alloy components, carbon, and other substances is obtained. From the black alloy thus obtained, materials such as valuable metal alloys, lithium oxide, and graphite can be recovered by material. At this time, the valuable metal alloy in the form of a metal is coated with lithium aluminate or lithium oxide, and the black alloys are finally turned into raw materials through additional processes such as leaching.

[0008] At this time, the carbon content and carbon shape in the recovered precious metal alloy vary depending on the size of the precious metal alloy, and the efficiency of the wet refining process using acid or base can be increased and the cost of the process can be reduced.

[0009] The technical problem to be solved by the present invention is to provide a composition for recovering valuable metals, which can increase the efficiency of the process and reduce the cost of the process when utilizing a valuable metal alloy raw material obtained from a spent battery by putting it into a wet refining process using an acid or a base.

[0010] Another technical problem to be solved by the present invention is to provide a method for recovering valuable metals for producing a composition for recovering valuable metals having the aforementioned advantages.

[0011] According to one embodiment of the present invention, a composition for recovering valuable metals comprises a valuable metal recovery alloy including a carbon layer and a lithium compound, wherein the carbon layer is disposed on at least a portion of a surface and an interior of the valuable metal recovery alloy, and the content of carbon (C) in the carbon layer may be 60 wt% or more based on 100 wt% of the carbon layer.

[0012] In one embodiment, at least a portion of the lithium compound can be bonded to at least a portion of a surface of the valuable metal recovery alloy. In one embodiment, the carbon layer is disposed on the surface of the valuable metal recovery alloy, and the total amount of Ni, Co, and Mn in the carbon layer can be 50 wt% based on 100 wt% of the carbon layer. In one embodiment, the carbon layer is disposed inside the valuable metal recovery alloy, and the carbon layer can be disposed as a band-shaped carburized layer on a cross-section of the valuable metal recovery alloy.

[0013] In one embodiment, the belt-shaped carbonized layer may have a ratio of a major axis to a minor axis of 2 or greater. In one embodiment, the lithium compound may include lithium oxide. In one embodiment, the lithium oxide may include lithium aluminum oxide. In one embodiment, the valuable metal may include at least one of lithium (Li), cobalt (Co), nickel (Ni), aluminum (Al), and manganese (Mn).

[0014] According to another embodiment of the present invention, a method for recovering valuable metals may include a step of preparing a battery or battery shreds in cell units, a step of dry heat treating the battery or the shreds at a temperature range of 1,100 to 1,800°C without going through a melting step, and a cooling step of cooling the dry heat treated resultant at a cooling rate of 10 to 50°C / minute or less.

[0015] In one embodiment, the high-temperature reduction reaction step may be performed in an atmosphere having an oxygen content of 5% or less. In one embodiment, the step of separating the resultant product after the cooling step by at least one of particle size separation and magnetic separation may be included.

[0016] In one embodiment, the step of separating the resultant product after the cooling step by at least one of particle size separation and magnetic separation may be performed prior to the magnetic separation and then the particle size separation. In one embodiment, the resultant product obtained from the step of dry heat treating the shredded material may separate a lithium compound bound to a portion of the surface of the valuable metal recovery alloy by an external force. In one embodiment, the step of preparing the battery or battery shredded material in units of cells may include a step of preprocessing the battery or battery shredded material in units of cells.

[0017] According to one embodiment of the present invention, a composition for recovering valuable metals comprises a carbon layer within a valuable metal alloy, thereby enabling the alloy particles to be easily crushed by an external force during a subsequent wet refining process, thereby reducing the diameter of the alloy and simultaneously increasing the specific surface area, thereby enhancing reactivity to sulfuric acid leaching. In addition, the carbon layer is disposed on the surface or within the valuable metal alloy, thereby facilitating the selective leaching of lithium from lithium oxide present on the alloy surface.

[0018] According to another embodiment of the present invention, a method for recovering valuable metals can provide a method for producing a composition for recovering valuable metals having the aforementioned advantages by controlling heat treatment and cooling conditions.

[0019] FIG. 1 is a SEM photograph of a unit metal recovery composition constituting a metal recovery composition according to one embodiment of the present invention.

[0020] Figure 2 is a flowchart of a battery processing method according to one embodiment of the present invention.

[0021] Figures 3 and 4 show SEM photographs of the precious metal alloy of the present invention.

[0022] Fig. 5 shows an SEM photograph of a cross-section of a metal alloy of the present invention.

[0023] Figures 6 to 8 are EPMA analysis results according to comparative examples of the present invention.

[0024] The terms first, second, and third, etc., are used to describe, but are not limited to, various parts, components, regions, layers, and / or sections. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, a first part, component, region, layer, or section described below may be referred to as a second part, component, region, layer, or section without departing from the scope of the present invention.

[0025] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present invention. As used herein, the singular forms "singular" and "comprising" include plural forms as well, unless the context clearly dictates otherwise. The word "comprising" as used herein specifies a particular feature, region, integer, step, operation, element, and / or component, but does not exclude the presence or addition of other features, regions, integers, steps, operations, elements, and / or components.

[0026] When a part is referred to as being "on" or "over" another part, it can be directly on or over the other part, or there may be other parts intervening. Conversely, when a part is referred to as being "directly on" another part, there are no other parts intervening.

[0027] Additionally, % in this specification means weight % unless otherwise specified.

[0028] Although not defined otherwise, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or overly formal unless otherwise defined.

[0029] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and the present invention is not limited thereto, and the present invention is defined solely by the scope of the claims set forth below.

[0030] FIG. 1 is a SEM photograph of a unit metal recovery composition constituting a metal recovery composition according to one embodiment of the present invention.

[0031] Referring to FIG. 1, a composition for recovering valuable metals (100) may include a core portion (110) containing valuable metals and a shell portion (120) disposed on at least a portion of the core portion (110). Specifically, the unit composition for recovering valuable metals (100) may be composed of a metal such as a valuable metal such as Ni, Co, or Mn in the core portion (110), and an oxide containing lithium may be bonded and disposed on the core portion (110).

[0032] The core portion (110) includes a valuable metal recovery alloy, and the valuable metal recovery alloy may include 45 wt% or more of the valuable metal and the remainder being impurities, based on 100 wt% of the total composition of the alloy. The valuable metal recovery alloy may include at least one of a valuable metal such as nickel (Ni), cobalt (Co), manganese (Mn), lithium (Li), carbon (C), aluminum (Al), copper (Cu), and the remainder being impurities. In the present specification, the valuable metal may mean an expensive metal component included in a battery, and may mean nickel, cobalt, manganese, aluminum, copper, and lithium. In one embodiment, the valuable metal may be 70 wt% or more.

[0033] In one embodiment, lithium (Li) among the above valuable metals may be included in a range of 0.01 to 5 wt%. By satisfying the above range, there is an advantage in that the Li recovery rate can be maximized during the Li refining process. If the lithium content exceeds the upper limit of the above range, there is a problem of reduced Ni and Co recovery rates, and if the content exceeds the lower limit of the above range, there is a problem of increased process costs due to a reduced Li recovery rate during the Li refining process.

[0034] In one embodiment, the valuable metal recovery alloy may contain copper (Cu) in an amount of 0.02 wt% or more. Specifically, the valuable metal recovery alloy may contain copper (Cu) in a range of 0.1 to 15 wt%. If the content of the copper is outside the upper limit of the range, there is a problem of process cost due to an increase in the amount of CuSO4 precipitated in leaching and solvent extraction, and if the content of the copper is outside the lower limit of the range, there is a problem of an increase in the amount of unreacted material due to difficulty in producing low-melting-point Ni-Co-Mn.

[0035] In one embodiment, the copper may be combined with nickel (Ni) among the valuable metals to form an alloy. In one embodiment, the nickel may be included in an amount ranging from 5 to 40 wt%. When the nickel is outside the upper limit of the above range, there is a problem of a decrease in the leaching rate due to the formation of nickel carbide (Ni3C), and when the nickel is outside the lower limit of the above range, there is a problem of a decrease in the Ni recovery rate in leaching and solvent extraction.

[0036] In one embodiment, the metal recovery alloy may contain carbon (C) in a range of 0.1 to 10 wt%. By satisfying the above range of carbon, the yield can be increased and the processing time in a wet process can be reduced. Specifically, the carbon may be contained in a range of 1 to 7 wt%.

[0037] If the upper limit of the above range is exceeded, the negative electrode material remains unreacted, which can lead to improper alloying and the remaining metal oxide within the positive electrode material. If the lower limit of the above range is exceeded, there is a risk of lithium loss due to high temperatures.

[0038] In one embodiment, the valuable metal recovery alloy may contain aluminum (Al) in a range of 0.25 to 30 wt%. If the content of aluminum is outside the upper limit of the range, there is a problem of reduced Ni and Co recovery rates during the leaching and solvent extraction processes, and if the content of aluminum is outside the lower limit of the range, there is a problem of reduced Li recovery rates due to difficulty in producing LiAlO2.

[0039] In one embodiment, the valuable metal recovery alloy may include a carbon layer in at least a portion of the metal recovery alloy. Specifically, the carbon layer may be disposed on the surface or within the metal recovery alloy. The carbon layer may be formed during the process of carburizing carbon from graphite contained in the negative electrode material within the spent battery into the metal recovery alloy.

[0040] Since the above-mentioned valuable metal recovery alloy includes the carbon layer, the alloy particles can be easily crushed by external force in a future wet refining process, thereby reducing the diameter and increasing the specific surface area, thereby improving the reactivity to sulfuric acid leaching. In addition, since the above-mentioned valuable metal alloy includes the carbon layer, there is an advantage in that selective leaching is easy when lithium of lithium oxide on the alloy surface is pre-leached.

[0041] In one embodiment, the carbon (C) content within the carbon layer may be 60 wt% or more, based on 100 wt% of the carbon layer. Specifically, the carbon content may be 60 to 98 wt%, specifically, the carbon content may be 70 to 95 wt%, and more specifically, 75 to 94 wt%.

[0042] Since the content of the carbon in the carbon layer satisfies the above-mentioned range, the valuable metal alloy particles are easily crushed by external force during wet refining in the subsequent process, thereby reducing the diameter and increasing the specific surface area, thereby improving the reactivity to sulfuric acid leaching and facilitating the pre-leaching of lithium.

[0043] In one embodiment, the carbon layer may be disposed within the metal recovery alloy. Specifically, when examining the cross-section of the metal recovery alloy, the carbon layer may be disposed as a band-shaped carburized layer on the cross-section of the metal recovery alloy. The band-shaped carburized layer may be formed by carbon precipitation at the grain boundaries of alloy particles.

[0044] Specifically, when the above-mentioned carburized layer is heated to a high temperature under reducing atmosphere conditions in a state where the anode oxide contains an excess of carbon, which is graphite used as a reducing agent, the carbon is carburized on the surface of the anode and combines with oxygen to be reduced to CO and CO2. At this time, as the temperature rises, the amount of carbon carburized in the anode increases, and this is because the solubility of carbon that can dissolve in the anode increases as the reduction temperature increases, so the amount of carburization increases. At this time, as the carbon is carburized, the melting point decreases, and even if the temperature increases further after the carbon is saturated, the melting point does not decrease further. Since the saturated carbon's saturation solubility decreases again during the cooling process, it begins to precipitate on the particle surface, and the carbon precipitated on the particle surface exists in the form of a band at the alloy grain boundary. At this time, if the cooling rate is slow, most of the carbon in the carbon layer is precipitated at the grain boundary, and if the cooling rate is very fast, the reduced anode material and carbon become a solid solution or precipitate in the form of dots inside the particle.

[0045] In one embodiment, the belt-shaped carburized layer may have a ratio of a major axis to a minor axis of 2 or more. Specifically, the ratio may be 10 or more. Specifically, the minor axis of the belt-shaped carburized layer refers to the thickness of the carburized layer, and the major axis of the belt-shaped carburized layer refers to the grain boundary of the cathode alloy. If the ratio is less than 2 to 10, the cooling rate is slow, so that a precipitated dot-shaped carburized layer is formed, and the desired effect of the present invention cannot be obtained.

[0046] Since the above-mentioned band-shaped carburized layer satisfies the above-mentioned ratio, it has the advantage of facilitating the penetration of carbon into the alloy, thereby improving the reactivity against sulfuric acid leaching in a future wet refining process. If the ratio of the major axis to the minor axis of the above-mentioned band-shaped carburized layer is outside the above-mentioned range, there is a problem in that the above-mentioned effect is not realized.

[0047] In one embodiment, the lithium in the metal recovery composition (10) is not reduced to form an alloy, unlike Ni, Co, and Mn, and can combine with the Al component in the battery to form lithium oxide.

[0048] In one embodiment, the metal recovery composition (10) may include a shell portion (120) disposed on a core portion (110). The shell portion (120) may be lithium oxide disposed on the core portion (110).

[0049] The lithium oxide may include, for example, lithium-aluminum oxide. The lithium-aluminum oxide may be a lithium-aluminum compound. The lithium-aluminum oxide may be formed by combining lithium and aluminum contained in the composition into an oxide through physical or chemical bonding.

[0050] In one embodiment, the lithium oxide may include LiAlO2, Li5AlO4, Li2CO3, and LiF. The LiAlO2, Li5AlO4, and Li2CO3 correspond to lithium oxides reacted during the high-temperature reduction reaction of the battery shreds, and LiF may be a lithium oxide detected by the electrolyte residual amount depending on the degree of pretreatment.

[0051] In one embodiment, the lithium compound may include XRD peaks having 2θ of at least one of 20.5 to 21.5°, 29.0 to 29.5°, 31.5 to 32.0°, 32.2 to 33.0°, 60.5 to 61.5°, 70.0 to 72.0°, 19.5 to 20.2°, 21.6 to 22.2°, 24.0 to 26.0°, 27.0 to 29.0°, 34.0 to 36.0°, 37.0 to 39.0°, 38.2 to 39.5°, 44.0 to 46.0°, 64.5 to 66.5°, and 77.77 to 79.77°.

[0052] In one embodiment, LiAlO2 can include XRD peaks of at least one of 20.5 to 21.5°, 29.0 to 29.5°, 31.5 to 32.0°, 32.2 to 33.0°, 60.5 to 61.5°, and 70.0 to 72.0°. Li5AlO4 can include XRD peaks of at least one of 19.5 to 20.2° and 21.6 to 22.2°.

[0053] The Li2CO3 composition may include at least one of XRD peaks from 24.0 to 26.0°, from 27.0 to 29.0°, from 34.0 to 36.0°, and from 37.0 to 39.0°. The LiF composition may include at least one of XRD peaks from 38.2 to 39.5°, from 44.0 to 46.0°, from 64.5 to 66.5°, and from 77.77 to 79.77°.

[0054] As described above, the precious metal recovery composition (10) has an XRD peak value of at least one of LiAlO2, Li5AlO4, Li2CO3, and LiF, and it can be confirmed that a lithium compound is attached and arranged on a core portion including the precious metal.

[0055] In one embodiment, the lithium compound partially bonded to the surface of the valuable metal recovery alloy can be separated using a wet process. In another embodiment, the lithium compound can be separated from the valuable metal recovery alloy by mechanical or physical external force. In this way, not only can the valuable metal recovery alloy be recovered from the valuable metal recovery composition (10), but the lithium compound can also be separated simultaneously, thereby increasing the lithium recovery rate and reducing the amount of lithium lost.

[0056] In one embodiment, the composition for recovering valuable metals (10) may include a carbonaceous material. The carbonaceous material may be, for example, elemental carbon (C). The carbon content may range from 1% to 7%. By ensuring that the carbon content satisfies the above range, the wet processing of the composition for recovering valuable metals is advantageously optimized.

[0057] When the content of the carbon exceeds the upper limit of the above range, there is a problem of a decrease in the leaching rate due to the formation of nickel carbide (Ni3C), and when the content of the carbon exceeds the lower limit of the above range, there is a problem of a decrease in the recovery rate of valuable metals such as Ni and Co in solvent extraction after the leaching process due to an increase in the content of other impurities such as Si.

[0058] In one embodiment, the composition for recovering valuable metals (10) may contain 10 to 30 wt % of aluminum (Al). By satisfying the above range of content, the aluminum can form a lithium compound through physical or chemical bonding with lithium, and as the lithium compound is separated in the future, there is an advantage in that the yield of lithium can be increased.

[0059] If the content of the above aluminum exceeds the upper limit of the above range, there is a problem of increased cost of Ni, Co solvent extraction and crystallization process and decreased Ni, Co recovery rate due to excessive generation of Al2(SO4)3 in the leaching and solvent extraction process. If the content of the above aluminum exceeds the lower limit of the above range, there is a problem of inferior formation of Li-Al-O oxide due to insufficient aluminum content.

[0060]

[0061] In one embodiment, the unit price metal recovery composition (100) includes aluminum (Al), and the aluminum (Al) may have a concentration gradient that gradually increases from the interface between the core portion (110) and the shell portion (120) toward the shell portion (120). The concentration gradient of aluminum (Al) increases as it moves toward the shell portion (120) because an oxide including aluminum is attached to the core portion (110) including the price metal alloy.

[0062] According to another embodiment of the present invention, a method for recovering valuable metals may include the steps of preparing battery shreds, dry heat treating the shreds, and cooling the dry heat treated resultant. The method may be a method for producing an alloy having a high concentration content of a valuable metal recovery alloy, and in particular, a method for producing an alloy having a higher concentration content of valuable metals compared to a black powder that has undergone an initial crushing step. In addition, the composition for recovering valuable metals and the alloy for recovering valuable metals produced through the above production method are the same as those in the aforementioned Fig. 1, as long as they do not contradict each other.

[0063] The step of preparing battery shredder is a step of preparing the parent material of the battery shredder by shredding it, or a step of preparing the shredded material itself. The parent material of the battery shredder may include waste batteries that have reached the end of their useful life, scrap constituting the waste batteries, positive electrode materials such as jelly rolls and slurry, defective products generated during the manufacturing process, residues within the manufacturing process, and waste materials generated during the manufacturing process, for example, waste materials from the manufacturing process of lithium ion batteries. The shredded material itself may be a shredded product itself, such as black powder.

[0064] In one embodiment, the step of preparing a battery or battery shredder in a unit cell manner may further include a step of shredding the material that serves as the parent material of the battery shredder, if the material is prepared by shredding the material. The shredder may be used to obtain the parent material of the battery shredder. The shredding may include, but is not limited to, crushing the waste battery by applying physical or mechanical force and pulverizing the waste battery into fine powder. The crushing step may separate some large impurities, such as aluminum (Al), copper (Cu), iron (Fe), and plastic, from the components contained in the waste battery. The state in which the large impurities are separated is called black powder, and the crushing step may produce battery shredder such as black powder.

[0065] In one embodiment, the battery shredder is intended for recovering valuable metals from spent batteries and may have a layered structure including a separator on which a positive electrode or a negative electrode is laminated on at least one surface. Specifically, the layered structure may include a configuration in which the positive electrode or the negative electrode is included on one 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.

[0066] The above layered structure includes, for example, any one of anode-separator-cathode, anode-separator, separator-anode, separator-cathode, and cathode-separator, and for example, anode-separator-cathode-separator-anode-separator-cathode may have a three-layered layered structure. Specifically, the battery shredder may have a predetermined thickness in the thickness direction as at least one or more layers are laminated.

[0067] In one embodiment, the battery shredder may satisfy the following condition 1.

[0068] <Condition 1> The above layered structure may be a laminated structure having 1 or more layers and 7 or fewer layers.

[0069] The above-mentioned battery shredder may have a layered structure having a laminated structure of one or more layers and no more than seven layers. Specifically, the layered structure may have a laminated structure of one or more layers and no more than five layers.

[0070] The above layered structure can minimize the temperature rise of the shredded material and allow an appropriate heating time to be taken as the layered structure is laminated within the above range. If the layered structure is laminated thicker than the upper limit of the above range, the temperature rise increases excessively and the heating time also increases, which may cause a fire as the material combusts.

[0071] In one embodiment, the battery shredder may satisfy the following condition 2.

[0072] <Condition 2> The size of the above battery shreds may be 100 mm or less based on the longest axis among the horizontal, vertical, and height directions.

[0073] In one embodiment, the battery shredder may have a size of 100 mm or less based on its longitudinal axis. Specifically, the size of the battery shredder may be 50 mm or less. If the size of the battery shredder is excessively large, there is a high possibility that the temperature of the battery shredder itself may rise above 100°C, which may cause a fire.

[0074] In one embodiment, the battery shredder may include aluminum (Al), manganese (Mn), lithium (Li), copper (Cu), cobalt (Co), nickel (Ni), carbon (C) and residual impurities. In one embodiment, the black powder includes 5 to 40 wt% of nickel (Ni), 1 to 20 wt% of cobalt (Co), 1 to 15 wt% of manganese (Mn), 0.5 to 5 wt% of lithium (Li), 10 to 70 wt% of carbon (C), 0.0001 to 20 wt% of aluminum (Al), and 0.0001 to 20 wt% of copper (Cu), and the sum of impurities such as iron (Fe) and phosphorus (P) may be less than 10 wt%. The components of the above black powder may vary depending on the ratio of nickel, cobalt, and manganese, and the nickel, cobalt, and manganese may be controlled by the positive electrode oxide in the lithium secondary battery when the lithium secondary battery is crushed.

[0075] In one embodiment, the step of crushing the material that becomes the parent material of the battery shredder may be a crushing method utilizing at least one of shear, compression, and tensile force. Specifically, the crushing may be performed by, for example, at least one of a hammer mill, a ball mill, and a stirred ball mill. The hammer mill may perform at least one of disintegration, punching, and milling, and it is clear that the crushing may be performed using various types of crushing or crushing devices, such as an industrial crusher, as a non-limiting example.

[0076] In one embodiment, the particle size of the battery shredder may be within 50 mm, specifically within 30 mm. A particle size larger than the above range would require more energy to be supplied in the heat treatment step described below, which is uneconomical.

[0077] In one embodiment, prior to the step of crushing the parent material of the battery shredder, a pretreatment step may be further included to prevent explosion or render the parent material of the battery shredder harmless. By including the pretreatment step, potentially explosive substances, such as electrolytes, within the parent material are removed, and the parent material, such as waste batteries, is discharged, thereby enhancing safety during the crushing step and increasing the recovery and productivity of valuable metals.

[0078] When using a battery as the parent material for the above-mentioned battery shredder, a step of freezing the battery may be included prior to crushing the battery shredder. Directly crushing the battery may result in an explosion or fire due to the electrolyte contained within the battery. Specifically, when a certain pressure is applied to the battery, the separator may be physically crushed, resulting in a short circuit that generates a high current, generating a spark. This spark may ignite the electrolyte, potentially resulting in a fire.

[0079] The step of freezing the battery is to freeze the battery to suppress ignition of the liquid electrolyte contained within the battery, and then perform the crushing process, so that no problem due to ignition of the electrolyte occurs.

[0080] In one embodiment, the step of freezing the battery may be performed by cooling it to a temperature in the range of -150°C to -60°C. If the temperature exceeds the upper limit of the above temperature range, the voltage remaining inside the battery may not decrease to 0 V, which may cause a battery reaction due to a short circuit, and the electrolyte may not be completely frozen, which is not suitable.

[0081] When the temperature exceeds the lower limit of the above temperature range, the electrolyte is sufficiently frozen, the internal voltage of the battery is also lowered to 0 V, and even if a short circuit occurs in which the positive and negative electrodes are in direct contact, no battery reaction occurs, so the battery temperature does not increase, and gas generation and combustion of the electrolyte do not occur. In addition, since the electrolyte is in a frozen state, the mobility of lithium ions is very low, so that the conduction characteristics according to lithium ion movement may be significantly reduced, and since vaporization of the electrolyte does not occur, flammable gases such as ethylene, propylene, and hydrogen may not be generated.

[0082] In the step of freezing the battery, if the temperature exceeds the upper limit of the above-mentioned temperature range, the voltage remaining inside the battery may not decrease to 0 V, which may result in a battery reaction due to a short circuit, and the electrolyte may not be completely frozen, which is not appropriate. If the temperature exceeds the lower limit of the above-mentioned temperature range, a large amount of energy must be invested for freezing, which is uneconomical.

[0083] In one embodiment, the step of freezing the battery may be performed by cooling the battery to a temperature range of -60 to -20°C under a vacuum atmosphere of 100 torr or less. The step of freezing the battery may be performed at a temperature range capable of suppressing the evaporation of the electrolyte. The vacuum atmosphere may be, for example, an inert gas, carbon dioxide, nitrogen, water, or a combination thereof.

[0084] Since the process is performed by controlling the pressure to a vacuum atmosphere of 100 torr or less, the supply of oxygen is suppressed, thereby preventing the electrolyte from reacting with oxygen, preventing an explosion caused by this, and suppressing the vaporization of the electrolyte, thereby preventing the generation of flammable gases such as ethylene, propylene, and hydrogen.

[0085] In the step of freezing the above battery, if it is performed in an air atmosphere or at a pressure exceeding 100 torr, there is a problem that voltage may remain within the battery, and since the electrolyte is not in a frozen state in the temperature range of -60 to -20°C, the electrolyte may vaporize and explode due to a spark generated when a short circuit occurs due to the remaining voltage.

[0086] In one embodiment, the preprocessing step may include a forced discharge step of the spent battery or battery shredder. The forced discharge step lowers the voltage of the spent battery or battery shredder, thereby enhancing stability and increasing the recovery and productivity of valuable metals during the shredding step. The forced discharge step may be performed, for example, by salt water discharge or electrical discharge.

[0087] The step of dry heat treating the above-mentioned crushed material may involve placing the crushed material in a heating furnace capable of raising the temperature to a temperature higher than the melting point. The step of dry heat treating the above-mentioned crushed material may involve heat treatment conditions that perform a high-temperature reduction reaction without going through a melting step.

[0088] In one embodiment, the heat treatment conditions may involve heat treatment conditions in the range of 1,100 to 1,800°C. Specifically, the range may be performed in the range of 1,150 to 1,400°C, and more specifically, 1,200 to 1,400°C. If the upper limit of the range is exceeded, there is a problem of loss due to lithium vaporization, and if the lower limit of the range is exceeded, there is a problem of excessive flake formation due to failure in sintering and reduction of alloy elements. In the above temperature range, the reduction reaction can be performed in a state where carbon in the crushed material is minimally burned and carbon dioxide generation is almost non-existent.

[0089] In one embodiment, the step of dry heat treating the shredded material may be performed in a gas atmosphere of at least one of an inert gas, carbon dioxide, carbon monoxide, and a hydrocarbon gas. The inert gas may include, for example, at least one of argon and nitrogen. By performing the reduction reaction of the shredded material in the gas atmosphere, a valuable metal recovery alloy comprising the valuable metal contained in the shredded material as a component can be effectively recovered.

[0090] In one embodiment, a portion of the gaseous atmosphere may contain impurities containing residual oxygen. If the oxygen content among the impurities is high, it may combine with the components of the shredded material during the reduction reaction to form carbon dioxide, which may then be gasified together with the lithium, making recovery difficult.

[0091] In one embodiment, the oxygen content in the dry heat treatment step may be 5% or less. Specifically, the oxygen content may be 1% or less, and more specifically, 0.1% or less. Specifically, if the partial pressure of oxygen exceeds the aforementioned range, there is a problem of lithium loss and large amounts of carbon dioxide being generated in local high-temperature conditions.

[0092] Specifically, in the dry heat treatment step, a composition for recovering valuable metals is provided by alloying components such as nickel, cobalt, manganese, and lithium-containing oxides in the crushed material, which may include valuable metals and residual impurities. The composition for recovering valuable metals may include, for example, aluminum (Al), manganese (Mn), lithium (Li), copper (Cu), cobalt (Co), nickel (Ni), carbon (C), and residual impurities, and a detailed description thereof is the same as the composition for recovering valuable metals described above in FIG. 1, to the extent that it does not contradict the composition for recovering valuable metals.

[0093] The above-described metal recovery composition may include a lithium compound, and the lithium compound may be prepared by the reduction reaction. In one embodiment, the aluminum content in the metal recovery composition may be 0.25 to 30 wt %. The more aluminum is added, the more effective it is to lower the stabilization temperature when producing a lithium compound, for example, lithium-alumina (LiAlO2).

[0094] When the above aluminum content is outside the upper limit of the above range, Li-Al-O oxide (LiAl) with high Al2O3 content 11 O 17 ) there is a problem of lowering the Li recovery rate due to the generation. If the content of the aluminum is outside the lower limit of the above range, there is a problem of poor generation of Li-Al-O oxide due to insufficient Al2O3 content.

[0095] In one embodiment, a stirring process may be added within the heat treatment furnace. In one embodiment, a stirring process may be added within the heat treatment furnace. The stirring process may, for example, utilize a rotating body or gas to promote the reaction within the heat treatment furnace, which is a high-temperature reduction furnace, and ensure uniformity of the internal temperature. The valuable metal recovery composition may be recovered by the reduction reaction of the black powder within the heat treatment furnace.

[0096] The cooling step of cooling the dry heat-treated result may be a step for cooling the dry heat-treated result to assist in the leaching of the carbon layer within the metal alloy. Specifically, the cooling step may be a step for controlling the speed and shape of precipitation of carburized carbon along the grain boundaries during the reduction process of the cathode material.

[0097] In one embodiment, the cooling step of cooling the dry heat-treated resultant may be performed at a rate ranging from 10 to 50°C / min. Specifically, the cooling step may be performed at a rate ranging from 20 to 30°C / min.

[0098] As the cooling step lowers the temperature at the aforementioned cooling rate, there is an advantage in that the precipitated carbon is stably precipitated in a band shape at the grain boundary of the positive electrode alloy. However, as the cooling step is performed outside the aforementioned speed range, there is a problem in that the carbon is precipitated in a dot shape inside the particle or in a plane shape at the grain boundary based on the cross-section of the particle.

[0099] In one embodiment, the method may further include a step of separating the resultant product after the cooling step by at least one of particle size separation and magnetic separation. Specifically, the step of separating may separate the resultant product after the cooling step, for example, the valuable metal recovery composition, by at least one of particle size separation and magnetic separation. The particle size separation method may separate the particles according to their size or diameter, and may include various methods, for example, using a sieve. The magnetic separation method may separate the particles by using a magnetic substance and bringing them into contact with the magnetic substance, and various types of magnetic separation methods may be applied.

[0100] In one embodiment, the step of separating the resultant product after the cooling step by at least one of particle size separation and magnetic separation may be a step of separating by at least one of particle size separation, magnetic separation, and specific gravity difference separation. The specific gravity difference separation method is a method of separating particles by considering the difference in specific gravity of each substance, and for example, by using a specific solvent, particles can be separated based on the size of the specific gravity of the particles corresponding to the specific solvent, and various types of specific gravity difference separation methods can be applied.

[0101] In one embodiment, the step of separating the cooled crushed material by at least one of particle size separation and magnetic separation includes all of the steps of particle size separation, magnetic separation, and performing both particle size separation and magnetic separation, thereby separating the valuable metal recovery alloy. The step of performing only particle size separation can recover the valuable metal recovery alloy only by particle size separation of the valuable metal recovery composition having a particle diameter of 100 µm to 100 mm or less.

[0102] In the case of the magnetic separation, if the composition for recovering valuable metals includes a material having a particle size of 100 μm or less, the valuable metal can be recovered from the composition for recovering valuable metals using only the magnetic separation. In the case of the material having a particle size of 100 μm or less, since the particle size is similar to that of carbon, the recovery rate of the valuable metal lost through particle size separation alone can be increased through the magnetic separation.

[0103] In one embodiment, when the particle size separation and the magnetic separation are performed together, the magnetic separation may be performed first, followed by the particle size separation. By performing the magnetic separation first, the loss of the valuable metal recovery alloy from the valuable metal recovery composition having a particle size of 100 μm or less can be prevented.

[0104] In one embodiment, the step of separating the cooled crushed material by at least one of particle size separation and magnetic separation may further include the step of separating the valuable metal alloy from the lithium compound containing lithium disposed on the valuable metal. The step of separating the lithium compound containing lithium may be performed before or after the step of separating the cooled crushed material by at least one of particle size separation and magnetic separation.

[0105] The lithium compound may be, for example, a lithium-containing oxide, and may be separated by a physical external force. For a detailed description thereof, reference may be made to the composition for recovering valuable metals in FIG. 1, to the extent that it does not contradict the description. In this way, by separating the lithium-containing oxide by a physical external force, the recovery rate of not only valuable metals but also lithium can be increased.

[0106]

[0107] To further illustrate the present invention, examples of the present invention are described. The following examples are merely exemplary of the present invention, and the present invention is not limited to the examples described below.

[0108]

[0109] <Experimental Example>

[0110] <Example 1>

[0111] Steps for preparing a composition for recovering valuable metals

[0112] A cell, module, or pack, which is a spent electric vehicle battery, is prepared, which includes a positive electrode material containing lithium ions, a negative electrode material made of graphite, an aluminum current collector, a separator, an electrolyte, and a copper current collector. The spent battery is frozen at -30°C or lower, shredded, and then shredded under inert gas conditions using a shredder so that the longest length or width of the spent battery is 100 mm or less.

[0113] After obtaining a composition for recovering valuable metals by the method described above, the crushed battery waste was heat-treated at 1,300°C under conditions of an oxygen partial pressure of 0.5% to perform a reduction process. After the reduction process, the reduction resultant was cooled at a cooling rate of 25°C / min, thereby obtaining a composition for recovering valuable metals.

[0114] FIG. 1 is an SEM photograph of a composition for recovering valuable metals according to one embodiment of the present invention.

[0115] FIG. 2a and FIG. 2b show XRD analysis results of a composition for recovering valuable metals according to one embodiment.

[0116] Referring to FIGS. 1, 2a, and 2b, it can be seen that the composition for recovering valuable metals is arranged such that a lithium compound, specifically lithium oxide, is bonded to a valuable metal recovery alloy. This structure may be developed by performing the reduction process described above.

[0117]

[0118] <Comparative Example 1> - Cooling rate of 5 ℃ / min or less

[0119] A composition for recovering valuable metals was obtained under the same conditions as Example 1, except that the cooling rate was 3°C / min.

[0120]

[0121] <Comparative Example 2> - Reduction temperature 1,100 ℃ or lower

[0122] A composition for recovering valuable metals was obtained under the same conditions as Example 1, except that the reduction temperature was 1,100°C or lower.

[0123]

[0124] <Comparative Example 3> - Cooling rate of 100 ℃ / min or more

[0125] A composition for recovering valuable metals was obtained under the same conditions as Example 1, except that the cooling temperature in the cooling step was 100°C / min.

[0126]

[0127] <Evaluation Example 1> - Component content on alloy surface

[0128] Figures 3 and 4 show SEM photographs of the precious metal alloy of the present invention.

[0129] FIG. 3 and FIG. 4 are SEM photographs that can confirm the shape within a precious metal alloy according to one embodiment of the present invention.

[0130] Tables 1 and 2 below show the results of observing the surface of the precious metal alloy in Zone 1 (Spectrum 1) and Zone 2 (Spectrum 2) using SEM and measuring the component contents using EDAX. Zone 1 and Zone 2 are defined as follows, and the component contents were measured using the following method.

[0131] Area 1 (Spectrum 1): The gray area in Figs. 3 and 4, which are SEM images of the precious metal alloy, represents the carbon layer.

[0132] Spectrum 2: The bright colored area in Figures 3 and 4, which are SEM images of the precious metal alloy, represents a lithium-containing compound, specifically lithium aluminate (LiAlO2).

[0133] Zone C[wt%]O[wt%]Al[wt%]Mn[wt%]Fe[wt%]Co[wt%]Ni[wt%]Cu[wt%]Example 1Spectrum 176.432.58-3.48-3.6310.163.72Spectrum 29.4555.4534.59-0.24-0.26-

[0134] Zone C[wt%]O[wt%]Al[wt%]Mn[wt%]Co[wt%]Ni[wt%]Example 1Spectrum 192.586.35-0.41-0.67Spectrum 224.7647.0325.860.570.431.35

[0135] Looking at FIGS. 3 and 4 and Tables 1 and 2, it can be confirmed that Example 1 has a carbon content of 76 to 92% in the area 1 portion. This confirms that the surface of the valuable metal recovery alloy in the valuable metal recovery composition manufactured according to the example of the present invention is attached with graphite, or that the region includes a high carbon content due to graphite precipitated during the cooling process. In this way, it was confirmed that the comparative example, in which the oxygen concentration during the reduction process and the cooling speed during the cooling step are not within the scope of the present invention, had a low graphite content and thus could not form a carbon layer. In contrast, Example 1 has the advantage of including a carbon layer, so that the alloy particles can be easily pulverized by an external force during the wet refining process, and lithium of the lithium oxide can be pre-leached.

[0136] <Evaluation Example 2> - Component content of alloy cross-section

[0137] Fig. 5 shows an SEM photograph of a cross-section of a metal alloy of the present invention.

[0138] Figure 5 is a cross-section of a metal alloy according to one embodiment of the present invention, observed by SEM, and the components measured by EDAX. Specifically, Zone 1 (Spectrum 1) and Zone 2 (Spectrum 2) represent carbon, Zone 3 (Spectrum 3) represents a lithium compound combined with Al, and Zone 4 (Spectrum 4) represents an NCM alloy.

[0139] Table 3 below shows the results of observing the cross-sections of the precious metal alloys in Zone 1, Zone 2, Zone 3, and Zone 4 using SEM photographs and measuring the component contents using EDAX.

[0140] ZoneC[wt%]O[wt%]Al[wt%]P[wt%]Mn[wt%]Co[wt%]Ni[wt%]Cu[wt%]Example 1Spectrum 187.03-0.470.882.091.488.05-Spectrum 294.42----2.063.53-Spectrum 3-57.7042.30-----Spectrum 4----17.7513.6261.497.14

[0141] Looking at Table 3 above, in the cross-sectional photographs of alloy particles, the gray areas distributed in a band shape inside the particles represent carbon precipitated at the grain boundaries of the alloy particles in Zone 1 and Zone 2. As in the examples, it was confirmed that carburized carbon was precipitated in a band shape when the reducing atmosphere and oxygen concentration were within the scope of the present invention and the cooling rate was within the scope of the present invention. In contrast, in the comparative example, especially when the cooling rate is lower than in the examples, such as in Comparative Example 1, the precipitated carbon diffuses into the cross-section of the alloy particles, so the ratio of the major axis to the minor axis of the band-shaped carbon layer decreases, and there is a problem that carbon remains in the form of dots within the alloy. FIGS. 6 to 8 are EPMA analysis results according to the comparative examples of the present invention.

[0142] Referring to Fig. 6, in the case of Comparative Example 1 where the cooling rate is slow, it can be confirmed that the carbon carburized at high temperature does not have enough time to slowly diffuse to the particle surface, so the carburized layer is not observed within the droplet grain boundary where the reduced cathode material particles are agglomerated, but is only observed on the outer surface of the droplet.

[0143] Referring to Fig. 7, in the case of Comparative Example 2, where the reduction temperature is low, lithium aluminate is not coated on the surface of the positive electrode alloy, so the reduction temperature of the positive electrode material is low, and the amount of carbon carburized inside the particle is small, so it was confirmed that the cooling speed did not produce droplets of the reduced alloy well, and the precipitated carburized layer was also precipitated in the form of dots with a short major axis ratio.

[0144] As shown in Comparative Example 3, when the cooling rate is rapidly rapid, carbon that is carburized at high temperatures and melted inside the particles does not diffuse to the grain boundaries or the droplet surface and precipitates in a solid solution state inside. Specifically, it was confirmed that in the case of rapid cooling, carbon does not exhibit any particular tendency inside the cathode alloy droplet.

[0145]

[0146] The present invention is not limited to the above-described embodiments, but can be manufactured in a variety of different forms. Those skilled in the art will appreciate that the present invention can be implemented in other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

1. A valuable metal recovery alloy containing a carbon layer; and Containing lithium compounds, The carbon layer is disposed on at least a portion of the surface and interior of the metal recovery alloy, A composition for recovering valuable metals, wherein the carbon (C) content in the carbon layer is 60 wt% or more based on 100 wt% of the carbon layer.

2. In paragraph 1, A composition for recovering valuable metals, wherein at least a portion of said lithium compound is bound to at least a portion of a surface area of ​​said valuable metal recovery alloy.

3. In paragraph 1, The above carbon layer is arranged on the surface of the valuable metal recovery alloy, A composition for recovering valuable metals, wherein the total amount of Ni, Co, and Mn in the carbon layer is 50 wt% or less based on 100 wt% of the carbon layer.

4. In paragraph 1, The above carbon layer is arranged inside the valuable metal recovery alloy, A composition for recovering valuable metals, wherein the carbon layer is arranged as a carburized layer in a band shape on the cross-section of the valuable metal recovery alloy.

5. In paragraph 4, A composition for recovering precious metals, wherein the above belt-shaped carbonized layer has a ratio of the major axis to the minor axis of 2 or more.

6. In paragraph 1, The above lithium compound is a recovered material recovered from a spent battery containing lithium oxide.

7. In paragraph 6, The above lithium oxide is a recovered material recovered from a spent battery containing lithium aluminum oxide.

8. In paragraph 1, A composition for recovering valuable metals, wherein the valuable metal comprises at least one of lithium (Li), cobalt (Co), nickel (Ni), aluminum (Al), and manganese (Mn).

9. Step for preparing battery cells or battery shreds; A step of dry heat treating at a temperature range of 1,100 to 1,800° C without going through a melting step of the battery or the shredded material; A method for recovering valuable metals, comprising a cooling step of cooling the above dry heat-treated resultant at a cooling rate of 10 to 50° C. / min.

10. In paragraph 9, A method for recovering valuable metals, wherein the above high-temperature reduction reaction step is performed in an atmosphere having an oxygen content of 5% or less.

11. In paragraph 9, A method for recovering valuable metals, comprising a step of separating the resultant product that has undergone the above cooling step by at least one of particle size separation and magnetic separation.

12. In paragraph 9, A method for recovering valuable metals, wherein the step of separating the resultant product that has undergone the above cooling step by at least one of particle size separation and magnetic separation is performed first and then particle size separation is performed.

13. In paragraph 9, A method for recovering valuable metals, wherein the result obtained from the step of dry heat treating the above-mentioned crushed material is separated by an external force from a lithium compound bonded to a portion of the surface of the above-mentioned valuable metal recovery alloy.

14. In paragraph 9, A method for recovering valuable metals, wherein the step of preparing the battery or battery scrap in the unit of cells includes the step of preprocessing the battery or battery scrap in the unit of cells.

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