WO2025127687A1 - Valuable metal recovery composition and method of recovering valuable metal - Google Patents

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

The present invention relates to a composition for recovering valuable metals from waste batteries and a method for recovering valuable metals from waste batteries.

As the demand for electric vehicles increases worldwide, the problem of disposal of waste batteries generated from said electric vehicles is emerging as a social issue. In the case of lithium secondary batteries, which are the main raw materials of said waste batteries, organic solvents, explosive substances, and heavy metals such as Ni, Co, Mn, and Fe are contained, but in the case of Ni, Co, Mn, and Li, they have high scarcity value as valuable metals, and the recovery and recycling process after the lithium secondary batteries are discarded is emerging as an important research field.

Specifically, a lithium secondary battery mainly consists of copper and aluminum used as a current collector, Li, Ni, Co, Mn-containing oxides constituting a cathode material, and graphite utilized as an anode material, and includes a separator separating the cathode material and the anode 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, LiPF ₆ is used.

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 valuable metals.

Recycling for the purpose of recovery of battery raw materials generally involves dismantling, discharging, crushing, heat treatment, recovery, and wet processes of batteries to recover valuable metals. In the case of the above discharge, salt water discharge is performed, and substances such as Na, K, Mg, Ca, and Cl that are introduced at this time are included as impurities in the recovered raw materials.

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

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.

At this time, the carbon content and carbon shape in the recovered valuable metal alloy vary depending on the size of the valuable 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.

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 valuable metal alloy raw materials obtained from waste batteries by putting them into a wet refining process using acid or base.

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.

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.

In one embodiment, at least a portion of the lithium compound can be bonded to at least a portion of a surface area 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 carburized layer in a band shape on a cross-section of the valuable metal recovery alloy.

In one embodiment, the belt-shaped carbon 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).

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

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.

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 cell-unit battery or battery shredded material may include a step of preprocessing the cell-unit battery or battery shredded material.

According to one embodiment of the present invention, a composition for recovering valuable metals includes a carbon layer in a valuable metal alloy, so that the alloy particles are easily crushed by an external force in a post-process, a wet refining process, thereby reducing the diameter of the alloy and simultaneously increasing the specific surface area, thereby improving the reactivity to sulfuric acid leaching. In addition, there is an advantage in that the carbon layer is disposed on the surface or inside of the valuable metal alloy, making it easy to selectively leach lithium from lithium oxide on the surface of the alloy.

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.

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.

FIG. 2 is a flowchart of a battery processing method according to one embodiment of the present invention.

Figures 3 and 4 show SEM photographs of the valuable metal alloy of the present invention.

Figure 5 shows an SEM photograph of a cross-section of a valuable metal alloy of the present invention.

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

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 only used to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Thus, 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.

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

When a part is referred to as being "on" or "on" another part, it may be directly on or above the other part, or there may be other parts intervening. In contrast, when a part is referred to as being "directly on" another part, there are no other parts intervening.

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

Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Terms defined in commonly used dictionaries are additionally interpreted as having a meaning consistent with the relevant technical literature and the presently disclosed content, and are not interpreted in an ideal or very formal sense unless defined.

Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples, and the present invention is not limited thereby, and the present invention is defined only by the scope of the claims described below.

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.

Referring to FIG. 1, the composition for recovering valuable metals (100) may include a core portion (110) including a valuable metal 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 including lithium may be combined and disposed on the core portion (110).

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 valuable metals such as nickel (Ni), cobalt (Co), manganese (Mn), lithium (Li), carbon (C), aluminum (Al), and 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.

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

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%. When 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 CuSO ₄ precipitation in leaching and solvent extraction, and when the content of the copper is outside the lower limit of the range, it is difficult to produce low-melting-point Ni-Co-Mn, resulting in a problem of an increase in the amount of unreacted materials.

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 a range of 5 to 40 wt%. When the nickel is outside the upper limit of the range, there is a problem of a decrease in the leaching rate due to the formation of nickel carbide (Ni ₃ C), and when the nickel is outside the lower limit of the range, there is a problem of a decrease in the Ni recovery rate in leaching and solvent extraction.

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

If the upper limit of the above range is exceeded, there is a problem that the anode material remains unreacted, alloying is not properly performed, and the metal oxide remains in the cathode material. If the lower limit of the above range is exceeded, there is a problem that lithium loss due to high temperature may occur.

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 the 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 the aluminum is outside the lower limit of the range, it is difficult to produce LiAlO ₂ , resulting in a problem of reduced Li recovery rates.

In one embodiment, the valuable metal recovery alloy may include a carbon layer in at least a portion of the region. Specifically, the carbon layer may be disposed on the surface or inside of the valuable metal recovery alloy. The carbon layer may be formed in a process in which carbon of graphite included in the negative electrode material in the spent battery is carburized in the valuable metal alloy.

Since the above-mentioned valuable metal recovery alloy includes the carbon layer, the alloy particles can be easily crushed by an 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.

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

Since the content of the carbon in the carbon layer satisfies the above-mentioned range, the valuable metal alloy particles are easily crushed by an 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.

In one embodiment, the carbon layer may be arranged inside the valuable metal recovery alloy. Specifically, when looking at the cross-section of the valuable metal recovery alloy, the carbon layer may be arranged as a band-shaped carburized layer on the cross-section of the valuable metal recovery alloy. The band-shaped carburized layer may be formed by carbon precipitating at the alloy grain boundary.

Specifically, the carburized layer is a state in which the carbon, which is graphite used as a reducing agent as the anode oxide, is excessively heated to a high temperature under a reducing atmosphere condition, and 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 increases, 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 begins to precipitate on the surface of the particles during the cooling process, the saturated solubility decreases again, and the carbon precipitated on the surface of the particles thus exists in the form of a band at the grain boundary of the alloy particle. 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 and carbon become a solid solution or are precipitated in the form of dots inside the particles.

In one embodiment, the belt-shaped carburized layer may have a ratio of the major axis to the 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 positive electrode alloy. If the ratio is less than 2 to 10, the cooling rate is slow, so that a precipitated dot-shaped carburized layer is generated, and the effect intended for the present invention cannot be obtained.

Since the above-mentioned belt-shaped carburized layer satisfies the above-mentioned ratio, there is an advantage in that it facilitates the penetration of carbon into the alloy, thereby improving the reactivity to sulfuric acid leaching in a future wet smelting process. If the ratio of the major axis to the minor axis of the above-mentioned belt-shaped carburized layer is outside the above-mentioned range, there is a problem in that the above-mentioned effect is not expressed.

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 be combined with the Al component in the battery to form lithium oxide.

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).

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 by physically or chemically bonding with each other.

In one embodiment, the lithium oxide may include LiAlO ₂ , Li ₅ AlO ₄ , Li ₂ CO ₃ , and LiF. The LiAlO ₂ , Li ₅ AlO ₄ , and Li ₂ CO ₃ correspond to lithium oxides reacted during a high-temperature reduction reaction of the battery waste, and LiF may be a lithium oxide detected by the electrolyte residual amount depending on the degree of pretreatment.

In one embodiment, the lithium compound can 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°.

In one embodiment, LiAlO ₂ 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°. Li ₅ AlO ₄ can include XRD peaks of at least one of 19.5 to 20.2° and 21.6 to 22.2°.

The Li ₂ CO ₃ composition can include XRD peaks of at least one of 24.0 to 26.0°, 27.0 to 29.0°, 34.0 to 36.0°, and 37.0 to 39.0°. The LiF composition can include XRD peaks of at least one of 38.2 to 39.5°, 44.0 to 46.0°, 64.5 to 66.5°, and 77.77 to 79.77°.

As described above, the valuable metal recovery composition (10) has an XRD peak value of at least one of LiAlO ₂ , Li ₅ AlO ₄ , Li ₂ CO ₃ , and LiF, and it can be confirmed that a lithium compound is attached and arranged on a core portion including the valuable metal.

In one embodiment, the lithium compound partially bonded to the surface of the valuable metal recovery alloy can be separated by utilizing 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 also the lithium compound can be separated at the same time, so that the lithium recovery rate is high and the amount of lithium lost can be reduced.

In one embodiment, the metal recovery composition (10) may include a carbon-based material. The carbon-based material may be, for example, a carbon (C) element. The content of the carbon may be in the range of 1% to 7%. By satisfying the above range of carbon content, there is an advantage in optimizing the wet processing of the metal recovery composition.

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 (Ni ₃ C), 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.

In one embodiment, the composition for recovering valuable metals (10) may contain 10 to 30 wt % of aluminum (Al). When the content of the aluminum satisfies the above range, a lithium compound can be formed 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.

When the content of the above aluminum is outside the upper limit of the above range, there is a problem of increased cost of the Ni, Co solvent extraction and crystallization process and decreased Ni, Co recovery rate due to excessive production of Al ₂ (SO ₄ ) ₃ in the leaching and solvent extraction process. When the content of the above aluminum is outside the lower limit of the above range, there is a problem of inferior production of Li-Al-O oxide due to insufficient aluminum content.

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 of the core portion (110) and the shell portion (120) toward the shell portion (120). The concentration gradient of aluminum (Al) increases toward the shell portion (120) because an oxide including aluminum is attached to the core portion (110) including the price metal alloy.

According to another embodiment of the present invention, a method for recovering valuable metals may include a step of preparing battery shreds, a step of dry heat-treating the shreds, and a cooling step of cooling the resultant of the dry heat treatment. As a method for producing an alloy having a high concentration content of a valuable metal recovery alloy, in particular, it may be 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 valuable metal recovery composition and the valuable metal recovery alloy produced through the above production method are the same as long as they do not contradict the aforementioned Fig. 1.

The step of preparing battery shreds is a step of preparing a material that serves as a parent material of battery shreds by shredding, or preparing the material itself after the shredding is completed. The parent material of the battery shreds may include waste batteries such as scrap, jelly rolls, and slurry constituting the waste batteries, defective products generated during the manufacturing process, residues within the manufacturing process, and debris generated during the manufacturing process, for example, waste materials within the manufacturing process of lithium ion batteries. The material itself after the shredding may be a product itself after the shredding is completed, for example, black powder.

In one embodiment, the step of preparing a battery or battery shreds in a unit cell manner may further include a step of shredding the material that is the parent material of the battery shreds when the material is prepared by shredding the material. The parent material of the battery shreds may be obtained as a shredder by using a shredder. The shredding may include, as a non-limiting example, 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 among the impurities included in the waste battery. A state in which the large impurities are separated is called black powder, and the crushing step may produce battery shreds such as black powder.

In one embodiment, the battery shredder is for recovering valuable metals from waste batteries and may have a layered structure including a separator having a cathode or anode laminated on at least one surface. Specifically, the layered structure may include a configuration in which the cathode or anode 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.

The above layered structure includes, for example, 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 since at least one or more layers are laminated.

In one embodiment, the battery shreds may satisfy the following condition 1.

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

The above battery shreds may have a layered structure having a laminated structure of 1 to 7 layers. Specifically, the layered structure may have a layered structure of 1 to 5 layers.

The above layered structure can minimize the temperature rise of the shredded material and take an appropriate heating time by being laminated within the above range. If the above layered structure is laminated thicker than the upper limit of the above range, the temperature rise excessively increases and the heating time also increases, which causes a problem of causing a fire by combustion.

In one embodiment, the battery shreds may satisfy the following condition 2.

<Condition 2> The size of the above battery shreds may be 100 mm or less based on the longest axis among the length, width, and height directions.

In one embodiment, the battery shreds may have a size of 100 mm or less based on the longitudinal axis. Specifically, the size of the battery shreds may be 50 mm or less. If the size of the battery shreds is excessively large, there is a problem that the temperature of the battery shreds themselves may rise to 100° C. or more, which may lead to a high possibility of a fire occurring.

In one embodiment, the battery scrap 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.

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

In one embodiment, the particle size of the battery shreds may be within 50 mm, specifically within 30 mm. If it is larger than the above range, there is an uneconomical problem because more energy is required in the heat treatment step described later.

In one embodiment, prior to the step of crushing the material that is the parent material of the battery shredder, a pretreatment step may be further included to prevent explosion or render harmless the parent material of the battery shredder. By including the pretreatment step, substances that may explode, such as electrolytes, in the parent material are removed, and by discharging the parent material, such as waste batteries, when the crushing step is performed, safety can be improved and the recovery and productivity of valuable metals can be increased.

In the case where a battery is used as the parent material of the above-mentioned battery shreds, a step of freezing the battery may be included before crushing the above-mentioned battery shreds. In the case where the battery is directly crushed, an explosion and fire may occur due to the electrolyte contained in the battery. Specifically, when a specific pressure is applied to the battery, the separator is physically crushed, and a high current is formed due to a short circuit, which generates a spark, and the spark may ignite the electrolyte, which may cause a fire.

The step of freezing the battery above is to freeze the battery to suppress ignition of the liquid electrolyte contained within the battery, and then perform the crushing process, so that problems due to ignition of the electrolyte do not occur.

In one embodiment, the step of freezing the battery may be performed by cooling to a temperature in the range of -150° C. to -60° C. If the temperature exceeds the upper limit of the temperature range, the voltage remaining inside the battery may not be reduced 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 appropriate.

When the lower limit of the above temperature range is exceeded, 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, a battery reaction does not occur, 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 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 may not be generated.

In the step of freezing the above battery, if the temperature exceeds the upper limit of the above temperature range, the voltage remaining inside the battery will not decrease to 0 V, which may cause a battery reaction due to a short circuit, and the electrolyte will not be completely frozen, which is not appropriate. If the temperature exceeds the lower limit of the above temperature range, there is an uneconomical problem because a lot of energy must be invested for freezing.

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

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.

In the step of freezing the above battery, if carried out 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.

In one embodiment, the preprocessing step may include a step of forcibly discharging the waste battery or the battery shreds. The forced discharging step is a step of lowering the voltage of the waste battery or the battery shreds, and when the shredding step is performed, stability can be increased and the recovery and productivity of valuable metals can be increased. The forced discharging step may perform, for example, salt water discharge or electric discharge.

The step of dry heat treating the above crushed material may include 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 crushed material may involve heat treatment conditions that perform a high-temperature reduction reaction without going through a melting step.

In one embodiment, the heat treatment conditions may involve heat treatment conditions in a range of 1,100 to 1,800° C. Specifically, the range may be performed in a 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 occurrence of flake formation due to failure to proceed with sintering and reduction of alloy elements. In the above temperature range, the reduction reaction can be performed in a state where carbon in the shredded material is minimally burned and carbon dioxide is hardly generated.

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

In one embodiment, a portion of the gas atmosphere may contain impurities including residual oxygen. If the content of oxygen among the impurities is high, it may form carbon dioxide by combining with the components of the shredded material during the reduction reaction process, and thus, there is a problem that it is difficult to recover by being gasified together with lithium.

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, more specifically, 0.1% or less. Specifically, when the partial pressure of the oxygen is outside the above-mentioned range, there is a problem of lithium loss and a large amount of carbon dioxide being generated in a local high-temperature state.

Specifically, in the dry heat treatment step, a composition for recovering valuable metals is provided which alloys components such as nickel, cobalt, manganese and lithium-containing oxides in the crushed material, and 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 that of the composition for recovering valuable metals described above in FIG. 1 as long as it is not contradictory.

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 %. As the aluminum is added, there is an effect of lowering the stabilization temperature when producing a lithium compound, for example, lithium-alumina (LiAlO ₂ ).

When the aluminum content exceeds the upper limit of the above range, there is a problem of reduced Li recovery rate due to the generation of Li-Al-O oxide (LiAl ₁₁ O ₁₇ ) with a high Al ₂ O ₃ content. When the aluminum content exceeds the lower limit of the above range, there is a problem of poor Li-Al-O oxide generation due to insufficient Al ₂ O ₃ content.

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

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

In one embodiment, the cooling step of cooling the dry heat treated resultant can be performed at a rate in the range of 10 to 50 °C/min. Specifically, the cooling step can be performed at a rate in the range of 20 to 30 °C/min.

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, and 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.

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 product according to the size or diameter of the particles, and may include various methods, for example, using a sieve. The magnetic separation method may separate the particles by using a magnetic body and contacting the magnetic body, and various types of magnetic separation methods may be applied.

In one embodiment, the step of separating the resultant product that has gone through 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 is a method of separating particles by considering the difference in specific gravity of each material, and for example, by utilizing 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.

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 performing the particle size separation, the magnetic separation, and the particle size separation and the magnetic separation together, thereby separating the valuable metal recovery alloy. The step of performing only the 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 ㎛ to 100 mm or less.

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

In one embodiment, when the particle size separation and the magnetic separation are performed together, the magnetic separation may be performed first, and then the particle size separation may be performed. 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.

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 and 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.

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 of Fig. 1, within a range that is not contradictory. In this way, by separating the lithium-containing oxide by a physical external force, the recovery rate of not only the valuable metal but also lithium can be increased.

In order to explain the present invention in more detail, examples of the present invention are described. The following examples are only examples of the present invention, and the present invention is not limited to the following examples.

<Experimental example>

<Example 1>

Steps for preparing a composition for recovering valuable metals

Prepare a cell, module, or pack, which is a spent battery of an electric vehicle, containing a positive electrode material containing lithium ions, an anode material of graphite, an aluminum current collector, a separator, an electrolyte, and a copper current collector. After freezing the spent battery at -30°C or lower, the spent battery is shredded, and the spent battery is shredded under inert gas conditions using a shredder device so that the longest length or width of the spent battery becomes 100 mm or less.

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

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

FIGS. 2a and 2b show XRD analysis results of a composition for recovering valuable metals according to one embodiment.

Referring to FIGS. 1, 2a, and 2b, it can be confirmed that the composition for recovering valuable metals is arranged such that a lithium compound, specifically, lithium oxide, is combined on a valuable metal recovery alloy. This structure may be expressed by performing the reduction process described above.

<Comparative Example 1> - Cooling speed 5 ℃/min or less

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

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

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.

<Comparative Example 3> - Cooling speed 100 ℃/min or more

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.

<Evaluation Example 1> - Component content on alloy surface

Figures 3 and 4 show SEM photographs of the valuable metal alloy of the present invention.

FIGS. 3 and 4 are SEM photographs that can confirm the shape within a valuable metal alloy according to one embodiment of the present invention.

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

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

Region 2 (Spectrum 2) : The bright-colored region in Figs. 3 and 4, which are SEM images of the precious metal alloy, represents a compound containing lithium, specifically lithium aluminate (LiAlO ₂ ).

zone C
[wt%] O
[wt%] Al
[wt%] Mn
[wt%] Fe
[wt%] Co
[wt%] Ni
[wt%] Cu
[wt%] Example 1 Spectrum 1 76.43 2.58 - 3.48 - 3.63 10.16 3.72 Spectrum 2 9.45 55.45 34.59 - 0.24 - 0.26 -

zone C
[wt%] O
[wt%] Al
[wt%] Mn
[wt%] Co
[wt%] Ni
[wt%] Example 1 Spectrum 1 92.58 6.35 - 0.41 - 0.67 Spectrum 2 24.76 47.03 25.86 0.57 0.43 1.35

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 carbon content includes a region with a high graphite 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 in the wet refining process, and lithium of the lithium oxide can be pre-leached.

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

Figure 5 shows an SEM photograph of a cross-section of a valuable metal alloy of the present invention.

Figure 5 is a SEM photograph of a cross-section of a metal alloy according to one embodiment of the present invention, and the components are measured using EDAX. Specifically, Spectrum 1 and Spectrum 2 represent carbon, Spectrum 3 represents a lithium compound combined with Al, and Spectrum 4 represents an NCM alloy.

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.

zone C
[wt%] O
[wt%] Al
[wt%] P
[wt%] Mn
[wt%] Co
[wt%] Ni
[wt%] Cu
[wt%] Example 1 Spectrum 1 87.03 - 0.47 0.88 2.09 1.48 8.05 - Spectrum 2 94.42 - - - - 2.06 3.53 - Spectrum 3 - 57.70 42.30 - - - - - Spectrum 4 - - - - 17.75 13.62 61.49 7.14

Looking at Table 3 above, in the cross-sectional photographs of the alloy particles, the gray area distributed in a band shape inside the particles is carbon precipitated at the grain boundaries of the alloy particles according to Zone 1 and Zone 2. As in the examples, it was confirmed that the carburized carbon was precipitated in a band shape since the reducing atmosphere and the 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, as in Comparative Example 1, the precipitated carbon diffuses into the cross-section of the alloy particles, so that the ratio of the major axis to the minor axis of the band-shaped carbon layer decreases and there is a problem that the 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.

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 that the carburized layer is not observed within the droplet grain boundary where the reduced cathode material particles are agglomerated, but only on the outer surface of the droplet.

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 cathode alloy, so the reduction temperature of the cathode 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.

As in Comparative Example 3, when the cooling rate is rapidly rapid, carbon that is carburized at a high temperature and melted inside the particle does not diffuse to the grain boundary or the droplet surface and is precipitated in a solid solution state inside. Specifically, it was confirmed that in the case of rapid cooling, carbon does not show any special tendency inside the cathode alloy droplet.

The present invention is not limited to the above embodiments, but can be manufactured in various different forms, and a person having ordinary skill in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

Claims (14)

A valuable metal recovery alloy comprising 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. In the first paragraph, 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. In the first paragraph, 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. In the first paragraph, 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. In the fourth paragraph, 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. In the first paragraph, The above lithium compound is a recovered material recovered from a spent battery containing lithium oxide. In Article 6, The above lithium oxide is a recovered material recovered from a spent battery containing lithium aluminum oxide. In the first paragraph, 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). A step for preparing a battery or battery shreds in cell units; 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. In Article 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. In Article 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. In Article 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. In Article 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. In Article 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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