WO2025135678A1 - Valuable metal recovery alloy and method for recovering valuable metal - Google Patents

Abstract

The present invention relates to a valuable metal recovery alloy, a valuable metal recovery composition, and a method for recovering valuable metal. The valuable metal recovery alloy comprises 45 wt% or more of a valuable metal and the balance of impurities, on the basis of 100 wt% of the total composition of the alloy, and satisfies equation 1 below: <Equation 1> 5.0 ≤ Cu/Ni ≤ 15.0

Description

Valuable metal recovery alloy and method for recovering valuable metal

The present invention relates to waste batteries, and to a valuable metal recovery alloy 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 converted into raw materials through additional processes such as leaching.

At this time, the content of components in the recovered precious metal alloy is controlled to increase the efficiency of the subsequent wet smelting process and reduce the cost of the process.

The technical problem to be solved by the present invention is to provide a valuable metal recovery alloy that 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.

Another technical problem to be solved by the present invention is to provide a method for recovering valuable metals for producing a valuable metal recovery alloy having the aforementioned advantages.

According to one embodiment of the present invention, a valuable metal recovery alloy comprises 45 wt% or more of valuable metal based on 100 wt% of the total composition of the alloy, the remainder being impurities, and satisfies the following equation 1.

<Formula 1>

5.0 ≤ [Cu]/[Ni] ≤ 15.0 %

(In the above formula 1, [Cu] and [Ni] represent the contents of Cu and Ni in the valuable metal recovery alloy, respectively)

In one embodiment, the metal recovery alloy satisfies the following equation 2:

<Formula 2>

30.0 ≤ [Cu]/[Mn] ≤ 55.0 %

(In the above formula 2, [Cu] and [Mn] represent the contents of Cu and Mn in the valuable metal recovery alloy, respectively)

In one embodiment, the metal recovery alloy satisfies the following equation 3:

<Formula 3>

50.0 ≤ [Cu]/[C] ≤ 200.0 %

(In the above formula 3, [Cu] and [C] represent the contents of Cu and C in the valuable metal recovery alloy, respectively)

In one embodiment, the valuable metal recovery alloy comprises a CuNi alloy. In one embodiment, the valuable metal recovery alloy can have XRD peak values of at least one of diffraction peaks of 2θ = 44 °± 1 °, 2θ = 51.5 °± 1.5 °, and 2θ = 75.5 °± 1.5 °.

In one embodiment, the alloy may include copper (Cu) in an amount of 0.02 to 5.00 wt% based on 100 wt% of the valuable metal recovery alloy. In one embodiment, the alloy may include carbon (C) in an amount of 5.0 wt% or less based on 100 wt% of the valuable metal recovery alloy.

According to another embodiment of the present invention, a method for recovering valuable metals may include the steps of preparing a battery or battery scrap in a cell unit, performing a dry heat treatment at a temperature range of 1,150 to 1,400° C. without going through a melting step of the battery or the scrap, and recovering a valuable metal recovery alloy having magnetism by magnetic separation using the resultant of the dry heat treatment with a magnetic strength of 800 to 4,500 G.

In one embodiment, the dry heat treatment step may be performed in an atmosphere having an oxygen content of 5% or less. In one embodiment, the dry heat treatment step may include a step performed in multiple stages, and the step performed in multiple stages may include a preliminary heat treatment step and a high-temperature heat treatment step performed at a temperature higher than that of the preliminary heat treatment step.

In one embodiment, the preliminary heat treatment step is performed at a temperature of 900° C. or less, and the temperature elevation rate of the preliminary heat treatment step can be performed at 5 to 15° C./min. In one embodiment, the high-temperature heat treatment step is performed at 900° C. or more, and the temperature elevation rate of the high-temperature heat treatment step can be performed at 2.5 to 7.5° C./min.

In one embodiment, a method for recovering valuable metals, comprising a cooling step after the high-temperature heat treatment step, wherein the cooling step is performed at a cooling rate of 20° C./minute or more. The high-temperature heat treatment step can be performed at 900° C. or more. In one embodiment, the step of recovering the valuable metal recovery alloy by magnetic separation can be performed in a wet manner.

In one embodiment, the step of recovering the valuable metal recovery alloy by magnetic separation can be performed in a range where the concentration of the solid content is 10 to 50%. In one embodiment, the result obtained from the step of dry heat treatment can 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 shreds may include the step of preprocessing the cell unit battery or battery shreds.

According to one embodiment of the present invention, the valuable metal recovery alloy controls the component contents of Cu and Ni, 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 a 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 alloy surface.

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

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.

FIG. 3 shows the results of XRD analysis on the change in state of Cu in a composition for recovering valuable metals according to one embodiment.

Figures 4a and 4b show the melting process of copper foil (Cu foil) in the heat treatment step of the battery shredder 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.

According to one embodiment of the present invention, a valuable metal alloy may include 45 wt% or more of a 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), 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, the metal recovery alloy may satisfy the following equation 1:

<Formula 1>

5.0 ≤ [Cu]/[Ni] ≤ 15.0 %

(In the above formula 1, [Cu] and [Ni] represent the contents of Cu and Ni in the valuable metal recovery alloy, respectively)

The above formula 1 means the content of copper to nickel in the valuable metal recovery alloy expressed as a percentage, and the value of the above formula 1 can be 5.0 to 15.0%. Specifically, the above formula 1 can be 5 to 15%, and more specifically, 10 to 14.5%. Since the above formula 1 satisfies the above-mentioned range, there is an advantage in that the time and process cost required for removing impurities in a wet smelting process can be reduced, and the recovery rate of Ni recovered as a magnetic body can be maximized.

If the above equation 1 exceeds the upper limit of the above-mentioned range, there may be problems such as an increase in the reaction temperature during the high-temperature reduction reaction, which increases the process cost for maintaining the temperature, and an increase in the time and cost for removing Cu in the process of leaching the alloy and removing impurities. On the other hand, there is a problem that some of the NCN alloy cannot be recovered because the strength of the magnetic force is weak during magnetic separation.

If the above equation 1 is out of the lower limit of the aforementioned range, the reaction temperature may be low during high-temperature reduction, so that NCM may not be completely reduced and may remain in the form of an oxide. In addition, since NCM oxide is a non-magnetic substance, there is a problem that the Ni weight % of the NCM alloy recovered as a magnetic product increases but the recovery rate decreases. On the other hand, due to the excessively strong magnetic force of the magnetic separator, not only the ferromagnetic NCM alloy but also paramagnetic and weakly magnetic substances are recovered, so there is a problem that the impurity content of the magnetic substance recovered as the NCM alloy increases.

In one embodiment, the metal recovery alloy may satisfy the following equation 2.

<Formula 2>

30.0 ≤ [Cu]/[Mn] ≤ 55.0 %

(In the above formula 2, [Cu] and [Mn] represent the contents of Cu and Mn in the valuable metal recovery alloy, respectively)

The above formula 2 means the content of copper to manganese in the valuable metal recovery alloy expressed as a percentage, and the value of the above formula 2 can be 30.0 to 55.0%. Specifically, the above formula 2 can be 35.0 to 48.0%, and more specifically, 40.0 to 46.0%. Since the above formula 2 satisfies the above-mentioned range, there is an advantage in that the recovery rate of Mn can be maximized as a magnetic product recovered through magnetic separation.

When the above formula 2 exceeds the upper limit of the above-mentioned range, there is a problem that the recovery rate of Mn decreases. When the above formula 2 exceeds the lower limit of the above-mentioned range, the weight % grade of Mn increases, but, similar to Cu/Ni in formula 1, there is a problem that the recovery rate of Mn decreases and the impurity content increases.

In one embodiment, the metal recovery alloy may satisfy the following equation 3.

<Formula 3>

50.0 ≤ [Cu]/[C] ≤ 200.0 %

(In the above formula 3, [Cu] and [C] represent the contents of Cu and C in the valuable metal recovery alloy, respectively)

The above formula 3 means the content of copper to carbon in the valuable metal recovery alloy expressed as a percentage, and the value of the above formula 3 can be 50.0 to 200.0%. Specifically, the above formula 3 can be 85 to 150%, more specifically, 100 to 150%, and even more specifically, 108 to 142%. Since the above formula 3 satisfies the above-mentioned range, there is an advantage in that the NCM alloy can be stably recovered with a high recovery rate and quality.

If the above Equation 3 is out of the upper limit of the above-mentioned range, when the Cu content is too high, the reaction temperature is very high during high-temperature reduction, which causes a problem of increased process costs. On the other hand, if the C content is too low, the reaction temperature is very low during high-temperature reduction, which means that C is not carburized into the grain boundaries of NCM, and in this case, NCM is not completely reduced and remains as some oxides, which causes a problem of decreased recovery rate of the NCM alloy. If the above Equation 3 is out of the lower limit of the above-mentioned range, a problem opposite to that described above may occur.

In one embodiment, the valuable metal recovery alloy may contain copper (Cu) in an amount of 0.02 wt % to 5.00 wt %, based on 100 wt % of the valuable metal alloy. Specifically, the valuable metal recovery alloy may contain copper in an amount of 0.1 wt % to 15 wt %.

If the content of the copper is outside the upper limit of the above 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 if the content of the copper is outside the lower limit of the above 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.

In one embodiment, the valuable metal recovery alloy may contain aluminum (Al) in a range of 0.25 to 30 wt %. Specifically, the aluminum (Al) may be 1.0 to 15.0 wt %, and more specifically, 8.0 to 9.5 wt %. When the content of the aluminum is outside the upper limit of the range, there is a problem of a decrease in the recovery rate of Ni and Co during the leaching and solvent extraction processes, and when the content of the aluminum is outside the lower limit of the range, it is difficult to produce LiAlO ₂ , and there is a problem of a decrease in the recovery rate of Li.

In one embodiment, the valuable metal recovery alloy may include carbon (C) in an amount of 5.0 wt% or less. Specifically, it may include 2.80 to 4.0 wt%, and more specifically, 2.96 to 3.84 wt%. Since the content of carbon satisfies the above-mentioned range, there is an advantage in that a carburized layer is formed in the valuable metal alloy, and pulverization is easy in a post-process, thereby increasing the recovery rate of the valuable metal.

If the content of the carbon is outside the upper limit of the above-mentioned range, there is a problem that it is difficult to separate carbon in a post-process. If the content of the carbon is outside the lower limit of the above-mentioned range, there is a problem that it is difficult to form a carburized layer, making it difficult to separate carbon from the alloy.

In one embodiment, the valuable metal alloy can include a Cu-Ni alloy. Specifically, the valuable metal alloy can include an alloy combining copper and nickel.

In one embodiment, the valuable metal recovery alloy can include, as XRD peak values, at least one of peak intensity values of 51.5°±1.5°, and 75.5±1.5°. The peak intensity values are expressed by including a Cu-Ni alloy, and the Cu-Ni can be expressed as copper is melted and remains in the valuable metal alloy during the high-temperature heat treatment step in the valuable metal recovery method and simultaneously combines with nickel to form an alloy.

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

In one embodiment, the valuable metal recovery composition (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 valuable metal recovery composition (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. A detailed description of the valuable metal recovery alloy of the core portion may be referred to the above.

In one embodiment, the lithium in the metal recovery composition (100) 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.

In one embodiment, the metal recovery composition (100) 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°. Li5AlO4 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 precious metal recovery composition (100) 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 precious 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 (100), 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 composition for recovering valuable metals (100) may contain 1 to 30 wt % of aluminum (Al). Specifically, the aluminum may contain 1.1 to 15.0 wt %. When the content of the aluminum satisfies the above range, a lithium compound can be formed through a physical or chemical bond 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 valuable 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 valuable metal alloy.

In one embodiment, a method for recovering valuable metals may include the steps of preparing battery shreds, performing a dry heat treatment on the shreds, and recovering a valuable metal alloy from the heat-treated resultant. As a method for producing an alloy having a high concentration content of a valuable metal recovery alloy, 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, in the case of a valuable metal recovery alloy produced through the above-described production method, it is the same as the range that does not contradict the above-described 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 include a step of shredding a material that is a parent material of the battery shreds, if the material is prepared by shredding the material that is a parent material of the battery shreds. The parent material of the battery shreds may be obtained as 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 above shredding step can separate some large impurities, such as aluminum (Al), copper (Cu), iron (Fe), and plastic, from the components included in the waste battery. The state in which the large impurities are separated is called black powder, and through the above shredding step, battery shreds such as black powder can be manufactured.

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.

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 1,150 to 1,400° C. Specifically, the range may be performed in a range of 1,200 to 1,300° C., and more specifically, 1,200 to 1,300° C. Since the heat treatment is performed in the above-described temperature range, copper in the battery shreds is melted and remains in the valuable metal alloy, so that it is advantageous in that it can be easily selected and recovered by a magnetic separation step, which is a subsequent process, and the reduction reaction can be performed in a state where carbon in the battery shreds is minimally burned and carbon dioxide is hardly generated.

If the upper limit of the above range is exceeded, there is a problem of loss due to lithium vaporization, and if the lower limit of the above range is exceeded, there is a problem of sintering and reduction of alloy elements not progressing.

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 content of oxygen in the dry heat treatment step may be 5% or less by volume. Specifically, the content of oxygen may be 1% or less, more specifically, 0.05% or less. Specifically, when the partial pressure of the oxygen is higher than the above value, there is a problem of lithium loss and a large amount of carbon dioxide being generated in a local high-temperature state. When the partial pressure of the oxygen is lower than the lower limit of the above range, there is a problem of a decrease in the Li recovery rate due to the low temperature of LiAlO ₂ formation.

In one embodiment, the dry heat treatment step may be performed in multiple stages. Specifically, the steps performed in multiple stages may include a preliminary heat treatment step and a high-temperature heat treatment step. Specifically, the high-temperature heat treatment step may be a heat treatment performed at a temperature higher than that of the preliminary heat treatment step.

In one embodiment, the preheat treatment step may be a step of preheating the battery shreds at 900° C. or lower. Specifically, the preheat treatment step may be a step of preheating at a temperature lower than the melting point of copper.

In one embodiment, the preheat treating step can be performed at a heating rate of 5 to 15 °C/min. Specifically, the preheat treating step can be performed at a heating rate of 8 to 12 °C/min, and more specifically, the preheat treating step can be performed at a heating rate of 9 to 11 °C/min.

In one embodiment, the high temperature heat treatment step can be performed at 900° C. or higher. Specifically, the high temperature heat treatment can be controlled to involve a step of heating at a temperature higher than the melting point of copper so that copper in the valuable metal recovery composition is partially melted and formed within the valuable metal alloy, and a carbon layer is included within the valuable metal alloy.

In one embodiment, the heating rate of the high temperature heat treatment step can be performed at 2.5 to 7.5 °C/min. Specifically, the heating rate can be 3.5 to 6.5 °C/min, more specifically, 4 to 6 °C/min.

In one embodiment, the heating rate of the high-temperature heat treatment step is controlled to be lower than the heating rate of the preliminary heat treatment step, so that copper in the valuable metal recovery composition is partially melted and formed in the valuable metal alloy, and a carbon layer is included in the valuable metal alloy, so that it can be easily introduced into a post-process.

By the above dry heat treatment step, a valuable metal recovery alloy comprising components such as nickel, cobalt, manganese and lithium-containing oxides in the crushed material, a lithium compound, copper and graphite disposed on at least a portion of the surface of the valuable metal recovery alloy or produced separately from the valuable metal recovery alloy can be obtained. The valuable metal recovery composition can include, for example, aluminum (Al), manganese (Mn), lithium (Li), copper (Cu), cobalt (Co), nickel (Ni), carbon (C) and the remainder of impurities, and detailed descriptions thereof are the same as those of the above-described valuable metal recovery composition as long as they do not contradict each other.

The above-mentioned metal recovery composition may include a lithium compound, and the lithium compound may be prepared by the reduction reaction. For example, the lithium compound may be lithium aluminate (2LiAlO ₂ ), and the reaction formula therefor is as follows.

[Reaction Formula 1]

Li ₂ O+Al ₂ O ₃ = 2LiAlO ₂

In one embodiment, the dry heat treatment step may add a stirring process 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.

The step of recovering the valuable metal alloy from the heat-treated resultant product can be performed by separating the heat-treated crushed material, for example, the valuable metal recovery alloy, through magnetic separation. The magnetic separation method can separate particles through contact with a magnetic body by utilizing a magnetic body, and various types of magnetic separation methods can be applied.

In one embodiment, the magnetic separation may be a step of magnetically separating and recovering a valuable metal recovery alloy having a magnetic strength of 800 to 4,500 G. Specifically, the strength of the magnetic strength may be 1,000 to 4,000 G, and more specifically, 2,000 to 3,000 G. When the strength of the magnetic strength satisfies the above-described range, the content of copper in the recovered valuable metal alloy satisfies Equations 1 to 3 described above, thereby improving the efficiency of the wet smelting process in the subsequent process and reducing the process cost.

In one embodiment, the magnetic separation can be performed dry. Specifically, the magnetic separation can use either a dry drum-type magnetic separator or a dry conveyor belt-type magnetic separator.

In another embodiment, the magnetic separation can be performed wet. Specifically, the magnetic separation can be performed by immersing the battery shreds in a tank or a batch containing a liquid material, and then performing magnetic separation using a magnet. Specifically, the wet magnetic separation can be performed under a condition where the pulp density, which indicates the concentration of the solid content, is 10 to 50%. Specifically, the pulp density can be performed at 20 to 40%. The wet magnetic separation has an advantage of improved sorting efficiency compared to the dry magnetic separation.

In one embodiment, prior to the step of preparing the battery shreds, a step of pretreating the battery may be included. The pretreating step may be a step of discharging and stabilizing the battery.

In one embodiment, the step of discharging and stabilizing the battery may be a step of performing a salt water discharge or an electric discharge. The step of discharging and stabilizing the battery may be a step of performing a salt water discharge or an electric discharge to lower and stabilize the voltage of the battery.

In one embodiment, the step of preprocessing the battery may include the step of freezing the battery. If 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 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 to prepare the battery

2750 g of NCM622 batteries were prepared, and the content ratio of the NCM622 batteries is as shown in Table 1 below.

Weight
(g) Weight
(%) Li
[%] Ni
[%] Co
[%] Mn
[%] Al
[%] Cu
[%] C
[%] Cu/Ni Cu/Mn Cu/C NCM622 2750.0 100 6.04 32.35 10.73 9.98 6.07 10.73 24.50 33.2 107.5 44

Battery shredding stage

It is preferable to use a method of freezing the above-mentioned waste battery at -30°C or lower and then crushing it, or to use a shredder device to crush the waste battery under atmospheric or inert gas conditions so that the longest length or width of the waste battery becomes 100 mm or less after discharging it under salt water discharge or electric discharge conditions. Specifically, an NCM622 battery having an SOC of 40% or less was frozen at -70°C for 24 hours or more and then crushed under a nitrogen atmosphere using a shredder so that the longest length becomes 100 mm or less.

High temperature heat treatment stage

After obtaining a composition for recovering valuable metals by the method described above, the crushed battery scrap was heat-treated at 1,250°C under an oxygen partial pressure condition of 0.5% to perform a reduction process. At this time, as a heat treatment reduction condition, the inert gas was purged to maintain the oxygen concentration in the furnace at 0.5%, and the temperature was increased at 10°C/min from room temperature to 900°C and at 5°C/min from 900 to 1,250°C, and the process was performed under the condition that the inert gas injection was stopped when the oxygen partial pressure in the furnace was continuously maintained at 0.5% or lower. In addition, after maintaining the sample at 1,250°C for 3 hours or more, the sample was cooled at a cooling rate of 20°C/min or more. A composition for recovering valuable metals was obtained through the reduction process described above.

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.

FIG. 3 shows the results of XRD analysis on the change in state of Cu in a composition for recovering valuable metals according to one embodiment.

Referring to Fig. 3, the change in state of the molten Cu of the composition for recovering valuable metals can be confirmed using XRD. It can be confirmed that the molten Cu in the reducing atmosphere of the present invention reacts with Ni and chemically bonds. This means that the molten Cu is melted and remains in the NCM alloy, and the content of Cu melted in the NCM alloy is controlled by the reduction temperature.

Figures 4a and 4b show the melting process of copper foil (Cu foil) in the heat treatment step of the battery shredder of the present invention.

Fig. 4a shows the state of copper foil before it is melted, and Fig. 4b shows the state of copper foil after it is melted. Referring to Figs. 4a and 4b, it can be confirmed that copper is melted at 1,050°C, and it can be confirmed that the bright copper part in Fig. 4a has completely disappeared in Fig. 4b.

Example 1 and Comparative Examples 1 to 3 are experimental results for reactants subjected to high-temperature reduction in an atmosphere with an oxygen concentration of 0.5% or less at a high-temperature heat treatment temperature range of 900 to 1500°C.

The results are as follows: The high-temperature reduction reactant was separated using a 100 μm sieve because most of the reactants under 100 μm are mainly composed of carbon and metallic Cu, and the reactants larger than 100 μm were separated into magnetic products and non-magnetic products using a magnetic separator with a magnetic strength of 3000 G. The components and ratios of the components were analyzed. The components of the fine particles smaller than 100 μm in size were analyzed to have a C content of 79.2%, a Li content of 1% or less, a Ni content of 3% or less, and Co a and Mn of 2% or less.

<Comparative Example 1>

The same procedure as Example 1 was followed, except that the high-temperature heat treatment step was performed at 1,100°C.

<Comparative Example 2>

The same procedure as Example 1 was followed, except that the high-temperature heat treatment step was performed at 1,500 ℃.

<Comparative Example 3>

The same procedure as Example 1 was followed, except that the heat treatment was performed at 900°C in the high-temperature heat treatment step.

<Evaluation Example 1> - Evaluation of components of a composition for recovering valuable metals

Table 2 below shows the components of a metal recovery composition manufactured by a high-temperature heat treatment process when subjected to magnetic separation.

The following components were measured using ICP-OES and C/S analyzer.

Mouth
[㎛] Li
[wt%] Ni
[wt%] Co
[wt%] Mn
[wt%] Al
[wt%] Cu
[wt%] C
[wt%] Cu/Ni
[%] Cu/Mn
[%] Cu/C
[%] Example 1
(1250℃) magnetism 5.73 32.50 14.07 9.95 9.12 4.08 3.45 12.6 41.0 118 Non-magnetic 5.67 0.92 0.32 1.79 6.69 35.40 21.73 3847.8 1977.7 163 Comparative Example 1
(1100℃) magnetism 5.64 28.30 11.01 9.52 12.67 7.81 5.57 27.6 82.0 140 Non-magnetic 1.24 3.57 1.48 1.16 1.11 3.52 79.20 98.6 303.4 4 Comparative Example 2
(1500℃) magnetism 0.37 51.90 16.50 3.10 1.29 0.10 3.68 0.2 3.2 2.7 Non-magnetic 1.80 0.46 0.07 12.40 4.17 0.01 0.12 2.2 0.1 8.3 Comparative Example 3
(900℃) magnetism 1.17 29.45 10.71 9.59 1.42 0.51 3.10 1.7 5.3 16.5 Non-magnetic 6.03 25.53 11.34 8.01 10.45 10.65 6.58 41.7 133.0 161.9

Looking at the example of Table 2 above, compared to the component ratio of the NCM622 battery of Table 1, the Cu/Ni, Cu/Mn, and Cu/C content ratios are consumed when the oxygen and carbon of the cathode material, NCM, reacts and converts into CO and CO2 gases during the high-temperature reduction process, and the Cu/C content ratio of the magnetic product rapidly increases from 44% to 118% due to the carbon and some of the burned carbon, and the non-magnetic product also increased to 16%. The Cu/Ni ratio and Cu/Mn ratio of the magnetic product were 12.6% and 41.0%, respectively, which was about half of that in Table 1. This is because the cathode material, NCM oxide, was reduced to metal and mostly separated as magnetic products. Accordingly, the Cu/Ni ratio and Cu/Mn ratio of the non-magnetic product increase to several thousand %. Comparative Example 1 is the result of magnetic separation of a material reacted at 1,100°C, which is slightly higher than 1,050°C at which Cu melts during the high-temperature reduction reaction, and it can be seen that the weight % of the valuable metal recovered as the magnetic product is somewhat lower than in Example 1. This is because the reaction rate of the reduction reaction is highly temperature-dependent, becoming faster as the temperature increases, and therefore the cathode material is not completely reduced compared to Example 1 and remains in the form of an oxide.

Comparative Example 2 was reacted at a high temperature of 1,500℃, so most of the carbon was burned and did not remain in the magnetic or non-magnetic products. In addition, since the reaction was performed at a temperature higher than the melting point of NCM and higher than the volatilization temperature of Li, most of the NCM was melted after reduction and discharged in the form of molten iron, and the weight % of NCM in the magnetic product was the highest. However, most of the Li was volatilized and could not be recovered as a magnetic product, and only a small amount could be recovered as a non-magnetic product in the form of slag.

Comparative Example 3 is a reaction performed at 900°C, which is lower than 1,050°C, the melting point of Cu, and then magnetic and non-magnetic products are separated. In general, the reduction reaction by carbon is actively performed when the temperature is higher than the temperature at which the Budweiser reaction occurs thermodynamically. Since Comparative Example 3 is a temperature similar to the Budweiser reaction temperature, although some of the cathode material is reduced and recovered as magnetic products, it is only at a significantly lower level than in Example 1. Therefore, the Cu/Ni ratio, Cu/Mn ratio, and Cu/C ratio are much lower than in the Example. Ultimately, the temperature of the high-temperature reduction reaction should be performed at an intermediate temperature of higher than 1100°C and lower than 1500°C.

<Evaluation Example 2> - Component Evaluation of Valuable Metal Alloy Component Evaluation of Valuable Metal Recovery Composition

In the dry heat treatment step, the reaction product manufactured at a high temperature reduction reaction temperature of 1,300 ℃ was subjected to magnetic separation, and the components of the magnetic product and the ratio of each component were compared according to the strength of the magnetic force.

<Example 2>

In the dry heat treatment step, a composition for recovering valuable metals was prepared in the same manner as in Example 1, except that the high-temperature reduction reaction temperature was set to 1,300°C. Thereafter, the prepared composition for recovering valuable metals was subjected to magnetic separation at a magnetic strength of 1,000 G to recover a magnetic body.

<Example 3>

The same procedure as in Example 2 was performed, except that the magnetic material was recovered by magnetic separation at a magnetic strength of 2,000 G.

<Example 4>

The same procedure as in Example 2 was followed, except that the ferrometal recovery composition was magnetically separated at a magnetic strength of 3,000 G to recover the magnetic material.

<Comparative Example 4>

The same procedure as in Example 2 was performed, except that the magnetic material was recovered by magnetic separation at a magnetic strength of 500 G.

<Comparative Example 5>

The same procedure as in Example 2 was performed, except that the magnetic material was recovered by magnetic separation at a magnetic strength of 5,000 G.

Table 3 below shows the components of magnetic and non-magnetic materials of the valuable metal recovery alloy when the valuable metal recovery composition is magnetically separated according to the strength of the magnetic force. At this time, the magnetic separation method was performed by the method below.

Magnetic separation method : Separation experiments were conducted according to magnetic strength using a magnetic separator, a drum-type wet magnetic separation device manufactured by Daebo Magnetic Co.

division Li
[wt%] Ni
[wt%] Co
[wt%] Mn
[wt%] Al
[wt%] Cu
[wt%] C
[wt%] Cu/Ni
[%] Cu/Mn
[%] Cu/C
[%] Example 2
(1000G) Magnet 5.64 35.50 15.70 10.50 8.41 4.23 3.18 11.9 40.3 133 Non-magnetic 7.72 1.29 0.56 1.74 13.20 27.90 17.70 2162.8 1603.4 158 Example 3
(2000G) Magnet 5.86 31.60 14.00 9.28 9.51 4.21 2.96 13.3 45.4 142 Non-magnetic 6.43 1.19 0.50 1.85 10.50 34.80 16.50 2924.4 1881.1 211 Example 4
(3000G) Magnet 5.09 32.90 14.50 9.54 8.49 4.15 3.84 12.6 43.5 108 Non-magnetic 6.87 0.82 0.35 1.94 10.20 34.50 19.30 4207.3 1778.4 179 Comparative Example 4
(500G) Magnet 6.63 32.20 14.30 9.73 9.38 5.82 2.75 18.1 59.8 212 Non-magnetic 8.66 1.45 0.64 1.78 14.30 28.10 20.40 1937.9 1578.7 138 Comparative Example 5
(5000G) Magnet 5.92 31.70 14.07 9.46 9.47 3.92 5.64 12.4 41.4 70.0 Non-magnetic 5.67 0.38 0.27 2.07 8.06 40.74 13.2 1,072.1 1,968.1 309

Looking at Table 3 above, when the magnetic strength of the example is in the range of 1000 to 3000 G, the Cu/Ni ratio of the magnetic product changes in a narrow range of 10 to 15%, the Cu/Mn ratio in the magnetic product in a narrow range of 40 to 50%, and the Cu/C ratio in the magnetic product in a narrow range of 100 to 150%, but in the comparative example of 500 G with a low magnetic strength, the Cu/Ni ratio in the magnetic product increases very sharply to 18.1%, the Cu/Mn ratio in the magnetic product in a narrow range of 59.8%, and the Cu/C ratio in the magnetic product in a narrow range of 212%. In addition, it can be seen that a significant amount of Li and NCM valuable metals remain in the non-magnetic product of 500 G and are not recovered as magnetic products. Comparative Example 5 is an experimental result for 5000 G with a very strong magnetic force. The Cu/Ni ratio and the Cu/Mn ratio are similar to the ratio range of the example, but the non-magnetic carbon is recovered as a magnetic product, so the Cu/C ratio increases to 70%, which is significantly reduced compared to the range of the example. This shows that when the magnetic force is too strong for the range suggested by the present invention during magnetic separation, even non-magnetic materials are recovered as magnetic products, which reduces the purpose of performing magnetic separation to separate valuable metals and carbon.

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 (17)

Based on 100 wt% of the total composition of the alloy, The metal content is 45 wt% or more, and the remainder includes impurities. A valuable metal recovery alloy satisfying the following equation 1. <Formula 1> 5.0 ≤ [Cu]/[Ni] ≤ 15.0 % (In the above formula 1, [Cu] and [Ni] represent the contents of Cu and Ni in the valuable metal recovery alloy, respectively) In the first paragraph, A valuable metal recovery alloy satisfying the following equation 2. <Formula 2> 30.0 ≤ [Cu]/[Mn] ≤ 55.0 % (In the above formula 2, [Cu] and [Mn] represent the contents of Cu and Mn in the valuable metal recovery alloy, respectively) In the first paragraph, A valuable metal recovery alloy satisfying the following equation 3. <Formula 3> 50.0 ≤ [Cu]/[C] ≤ 200.0 % (In the above formula 3, [Cu] and [C] represent the contents of Cu and C in the valuable metal recovery alloy, respectively) In the first paragraph, A valuable metal recovery alloy comprising a CuNi alloy. In the first paragraph, A precious metal recovery alloy having an XRD peak value of at least one diffraction peak among 2θ = 44 °± 1 °, 2θ = 51.5 °± 1.5 °, and 2θ = 75.5 °± 1.5 °. In the first paragraph, A valuable metal recovery alloy comprising copper (Cu) having a content of 0.02 to 5.00 wt% based on 100 wt% of the valuable metal recovery alloy. In the first paragraph, A composition for recovering valuable metals, comprising carbon (C) having a content of 5.0 wt% or less based on 100 wt% of a valuable metal recovery alloy. A step for preparing a battery or battery shreds in cell units; A step of dry heat treating at a temperature range of 1,150 to 1,400° C without going through a melting step of the battery or the shredded material; and A method for recovering a valuable metal, comprising a step of recovering a valuable metal recovery alloy having magnetic properties by magnetic separation using a magnetic strength of 800 to 4,500 G from the resultant product of the above dry heat treatment. In Article 8, A method for recovering valuable metals, wherein the above dry heat treatment step is performed in an atmosphere having an oxygen content of 5% or less. In Article 8, The above dry heat treatment step includes a step of performing in multiple stages, A method for recovering valuable metals, wherein the steps performed in the above multiple stages include a preliminary heat treatment step and a high-temperature heat treatment step performed at a temperature higher than the preliminary heat treatment step. In Article 8, The above preliminary heat treatment step is performed at a temperature of 900 ℃ or less, A method for recovering valuable metals, wherein the heating rate of the above preliminary heat treatment step is performed at 5 to 15°C/min. In Article 8, The above high temperature heat treatment step is performed at 900 ℃ or higher, A method for recovering valuable metals, wherein the heating rate of the high-temperature heat treatment step is performed at 2.5 to 7.5 ℃/min. In Article 8, After the above high temperature heat treatment step, a cooling step is included, A method for recovering valuable metals, wherein the cooling step is performed at a cooling rate of 20°C/min or higher. A method for recovering valuable metals, wherein the high-temperature heat treatment step is performed at 900°C or higher. In Article 8, A method for recovering valuable metals, wherein the step of recovering the above valuable metal recovery alloy by magnetic separation is performed in a wet manner. In Article 8, A method for recovering a valuable metal, wherein the step of recovering the above valuable metal recovery alloy by magnetic separation is performed in a range where the concentration of the solid content is 10 to 50%. In Article 8, A method for recovering valuable metals, wherein the result obtained from the above dry heat treatment step separates a lithium compound bound to a portion of the surface of the above valuable metal recovery alloy by an external force. In Article 8, 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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