Valuable metal recovery alloy and valuable metal recovery method

Abstract

The present invention relates to a valuable metal recovery alloy, a valuable metal recovery composition, and a valuable metal recovery method. The valuable metal recovery alloy contains 45% by weight or more of valuable metals and the remainder being impurities, based on 100% by weight of the total composition of the alloy, and satisfies the following formula 1. <Expression 1> 5.0 ≤ Cu / Ni ≤ 15.0%

Description

Technical Field

[0001] Relates to waste batteries, valuable metal recovery alloys recovered from waste batteries, and methods for recovering valuable metals.

Background Art

[0002] As the demand for electric vehicles has become active globally, the problem of treating waste batteries generated from said electric vehicles has emerged as a social issue. In the case of lithium secondary batteries, which are the main raw material for said waste batteries, they contain organic solvents, explosive substances, and heavy metal substances such as Ni, Co, Mn, and Fe. In the case of Ni, Co, Mn, and Li, their scarcity value as valuable metals is great, and the recovery and reuse processes after lithium secondary batteries are discarded have emerged as an important research field.

[0003] Specifically, lithium secondary batteries mainly consist of copper and aluminum used as current collectors, Li, Ni, Co, Mn-containing oxides constituting the positive electrode material, and graphite used in the negative electrode material. They also include a separator that separates the positive electrode material and the negative electrode material and an electrolyte injected into the separator. The electrolyte is composed of a solvent and a salt. As the solvent, mainly carbonate organic substances such as ethylene carbonate and propylene carbonate are mixed and used. As the salt, for example, LiPF6 is used.

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

[0005] Reuse for battery raw material recovery generally involves dismantling, discharging, crushing, heat treatment, recovery, and wet processing of batteries to recover valuable metals. In the case of discharge, saltwater discharge is performed, and at this time, substances such as Na, K, Mg, Ca, and Cl that are introduced are included as impurities in the recovered raw material.

[0006] After heat treatment, the recovered material yields different products depending on the heat treatment temperature. When heat-treated at temperatures below 600°C, it is called Black Powder, a powder mixture of Ni-Co-Mn-Li oxide and carbon (the negative electrode material). Since Al and Cu are removed beforehand, they may be present in very small amounts.

[0007] When the aforementioned 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 in the negative electrode material, resulting in a black alloy containing such alloy components, carbon, and other substances. From the black alloy thus obtained, valuable metal alloys, lithium oxide, and graphite can be recovered separately for each material. At this time, the valuable metal alloy in metallic form is coated with lithium aluminate or lithium oxide, and the black alloy is ultimately converted back into raw materials through additional processes such as leaching.

[0008] At this stage, the content of components in the recovered valuable metal alloy is controlled to increase the efficiency of the subsequent wet smelting process and reduce the costs of the process. [Overview of the project] [Problems that the invention aims to solve]

[0009] The technical problem that this invention aims to solve is to provide a valuable metal recovery alloy that can improve the efficiency of a process and reduce the costs of a process when valuable metal alloy raw materials obtained from waste batteries are used in a wet smelting process using an acid or a base.

[0010] Another technical problem that the present invention aims to solve is to provide a valuable metal recovery method for producing a valuable metal recovery alloy having the advantages described above. [Means for solving the problem]

[0011] In one embodiment of the present invention, the valuable metal recovery alloy has a total composition of 100% by weight of the alloy, with the valuable metal accounting for 45% by weight or more, and the remainder being impurities, satisfying the following formula 1. <Expression 1> 5.0 ≤ [Cu] / [Ni] ≤ 15.0% (In Equation 1 above, [Cu] and [Ni] represent the Cu and Ni content in the valuable metal recovery alloy, respectively.)

[0012] In one embodiment, the valuable metal recovery alloy satisfies the following equation 2. <Expression 2> 30.0 ≤ [Cu] / [Mn] ≤ 55.0% (In Equation 2 above, [Cu] and [Mn] represent the Cu and Mn content in the valuable metal recovery alloy, respectively.)

[0013] In one embodiment, the valuable metal recovery alloy satisfies the following equation 3. <Expression 3> 50.0 ≤ [Cu] / [C] ≤ 200.0% (In Equation 3 above, [Cu] and [C] represent the Cu and C content in the valuable metal recovery alloy, respectively.)

[0014] In one embodiment, the valuable metal recovery alloy includes a CuNi alloy. In one embodiment, the valuable metal recovery alloy may have at least one diffraction peak with XRD peak values ​​of 2θ=44°±1°, 2θ=51.5°±1.5°, and 2θ=75.5°±1.5°.

[0015] In one example, copper (Cu) may be included in an amount of 0.02 to 5.00% by weight or less, based on 100% by weight of the recovered metal alloy. In another example, carbon (C) may be included in an amount of 5.0% by weight or less, based on 100% by weight of the recovered metal alloy.

[0016] Another embodiment of the present invention provides a method for recovering valuable metals, which may include the steps of: preparing a battery or battery crushed material in cell units; dry heat treating the battery or crushed material in a temperature range of 1,150 to 1,400°C without going through a melting step; and recovering a valuable metal recovery alloy having magnetism with a magnetic force of 800 to 4,500 G from the dry heat treated product by magnetic separation.

[0017] In one embodiment, the dry heat treatment step may be carried out in an atmosphere with an oxygen content of 5% or less. In one embodiment, the dry heat treatment step may include a multi-stage step, and the multi-stage step may include a pre-heat treatment step and a high-temperature heat treatment step carried out at a higher temperature than the pre-heat treatment step.

[0018] In one embodiment, the preheat treatment step may be performed at a temperature of 900°C or lower, and the heating rate of the preheat treatment step may be 5 to 15°C / min. In another embodiment, the high-temperature heat treatment step may be performed at a temperature of 900°C or higher, and the heating rate of the high-temperature heat treatment step may be 2.5 to 7.5°C / min.

[0019] In one embodiment, the process includes a cooling step after the high-temperature heat treatment step, the cooling step is performed at a cooling rate of 20°C / min or more, and the high-temperature heat treatment step may be performed at 900°C or higher.

[0020] In one embodiment, the step of recovering the valuable metal recovery alloy by magnetic separation may be performed in a wet manner.

[0021] In one embodiment, the step of magnetically separating and recovering the valuable metal recovery alloy may be performed within a range where the ore liquid concentration indicating the solid content concentration is 10 to 50%. In one embodiment, the resultant obtained from the step of dry heat treatment may separate the lithium compound bonded to a part of the surface of the valuable metal recovery alloy by an external force.

[0022] In one embodiment, the step of preparing the battery or battery crushed material of the cell unit may include a step of pretreating the battery or battery crushed material of the cell unit.

Advantages of the Invention

[0023] The valuable metal recovery alloy according to an embodiment of the present invention controls the component contents of Cu and Ni, so that in the subsequent wet smelting process, the alloy particles are easily crushed by an external force, the diameter of the alloy decreases, and the specific surface area increases, improving the reactivity with respect to the leaching of sulfuric acid. In addition, a carbon layer is disposed on the surface or inside of the valuable metal alloy, which has the advantage of facilitating the selective leaching of lithium from the lithium oxide on the alloy surface.

[0024] The valuable metal recovery method according to another embodiment of the present invention can provide a method for manufacturing a valuable metal recovery alloy having the above-described advantages by controlling heat treatment and cooling conditions.

Brief Description of the Drawings

[0025] [Figure 1] FIG. 1 is a SEM photograph of a composition for valuable metal recovery according to an embodiment of the present invention.

[0026] [Figure 2a] FIG. 2a shows the XRD analysis results of a composition for valuable metal recovery according to an embodiment.

[0027] [Figure 2b] FIG. 2b shows the XRD analysis results of a composition for valuable metal recovery according to an embodiment.

[0028] [Figure 3] Figure 3 shows the results of XRD analysis on the state change of Cu in a valuable metal recovery composition according to one embodiment.

[0029] [Figure 4a] Figure 4a shows the melting process of copper foil (Cu foil) in the heat treatment step of battery fragments according to the present invention.

[0030] [Figure 4b] Figure 4b shows the melting process of copper foil (Cu foil) in the heat treatment step of battery fragments according to the present invention. [Modes for carrying out the invention]

[0031] The terms First, Second, and Third are used to describe various parts, components, regions, layers, and / or sections, but are not limited to these. These terms are used solely to distinguish one part, component, region, layer, or section from other parts, components, regions, layers, or sections. Accordingly, the First Part, component, region, layer, or section described below may be referred to as the Second Part, component, region, layer, or section, to the extent that it does not fall outside the scope of the present invention.

[0032] The technical terms used herein are for the sole purpose of referring to specific embodiments and are not intended to limit the invention. The singular forms used herein also include plural forms unless the text explicitly indicates otherwise. The meaning of “including” as used in this specification is to embody specific characteristics, regions, integers, steps, operations, elements, and / or components, and does not exclude the presence or addition of other characteristics, regions, integers, steps, operations, elements, and / or components.

[0033] When we say that one part is "on top of" another part, it means that it is directly on top of the other part, or that the other part exists between them. In contrast, when we say that one part is "directly on top of" another part, it means that the other part is not in between them.

[0034] Furthermore, unless otherwise specified, percentages in this specification refer to percentages by weight.

[0035] Although not defined differently, all terms used herein, including technical and scientific terms, have the same meaning as those generally understood by a person of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries are additionally interpreted to have the meaning consistent with the relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined.

[0036] The embodiments of the present invention will be described in detail below. However, these are presented as examples only and do not limit the present invention, which is defined only by the scope of the claims described later.

[0037] Based on a 100% by weight total composition of a valuable metal alloy silver alloy according to one embodiment of the present invention, the valuable metal may contain 45% by weight or more and the remainder being impurities. The valuable metal recovery alloy may contain at least one of the 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 this specification, valuable metal may mean a valuable metallic component contained in a battery, and may also mean nickel, cobalt, manganese, aluminum, copper, and lithium. In one embodiment, the valuable metal may be 70% by weight or more.

[0038] In one embodiment, the valuable metal recovery alloy can satisfy the following formula 1. <Expression 1> 5.0 ≤ [Cu] / [Ni] ≤ 15.0% (In Equation 1 above, [Cu] and [Ni] represent the Cu and Ni content in the valuable metal recovery alloy, respectively.)

[0039] The above formula 1 represents the percentage of copper content relative to nickel in the valuable metal recovery alloy, and the value of formula 1 may be between 5.0% and 15.0%. Specifically, formula 1 may be between 5% and 15%, and more specifically, between 10% and 14.5%. By satisfying the above range of formula 1, it is possible to reduce the time and process costs required for removing impurities in the wet smelting process, and to maximize the recovery rate of Ni recovered as a magnetic material.

[0040] If Equation 1 falls outside the upper limit of the range mentioned above, the reaction temperature during the high-temperature reduction reaction will be high, increasing the process costs for maintaining the temperature. This can lead to problems such as increased time and cost for removing Cu in the process of leaching the alloy to remove impurities. On the other hand, there is a problem that the magnetic force during magnetic separation may be too weak, preventing the recovery of some of the NCN alloy.

[0041] If Equation 1 falls outside the lower limit of the range mentioned above, the reaction temperature during high-temperature reduction is low, which may prevent complete reduction of NCM, leaving some residue in oxide form. Furthermore, since NCM oxide is nonmagnetic, the Ni weight% of the NCM alloy recovered as a magnetic product increases, but the recovery rate decreases. On the other hand, the excessively strong magnetic force of the magnetic separator can recover not only the ferromagnetic NCM alloy but also paramagnetic and weakly magnetic materials, leading to an increase in the impurity content of the magnetic material recovered as NCM alloy.

[0042] In one embodiment, the valuable metal recovery alloy can satisfy the following formula 2. <Expression 2> 30.0 ≤ [Cu] / [Mn] ≤ 55.0% (In Equation 2 above, [Cu] and [Mn] represent the Cu and Mn content in the valuable metal recovery alloy, respectively.)

[0043] The above equation 2 represents the percentage of copper content relative to manganese in the valuable metal recovery alloy, and the value of equation 2 may be between 30.0% and 55.0%. Specifically, equation 2 may be between 35.0% and 48.0%, and more specifically, between 40.0% and 46.0%. The advantage of equation 2 satisfying the above range is that the recovery rate of Mn as a magnetic product recovered through magnetic separation can be maximized.

[0044] If Equation 2 falls outside the upper limit of the range mentioned above, there is a problem of decreased Mn recovery. If Equation 2 falls outside the lower limit of the range mentioned above, the weight % grade of Mn increases, but, similar to Cu / Ni in Equation 1, there is a problem of decreased Mn recovery and increased impurity content.

[0045] In one embodiment, the valuable metal recovery alloy can satisfy the following formula 3. <Expression 3> 50.0 ≤ [Cu] / [C] ≤ 200.0% (In Equation 3 above, [Cu] and [C] represent the Cu and C content in the valuable metal recovery alloy, respectively.)

[0046] The above-mentioned formula 3 represents the copper content relative to carbon in the valuable metal recovery alloy as a percentage, and the value of formula 3 may be between 50.0% and 200.0%. Specifically, formula 3 may be between 85% and 150%, more specifically between 100% and 150%, and even more specifically between 108% and 142%. The advantage of formula 3 satisfying the above-mentioned range is that NCM alloy can be recovered stably with a high recovery rate and quality.

[0047] If Equation 3 falls outside the upper limit of the range described above, an excessively high Cu content means that the reaction temperature during high-temperature reduction is very high, leading to increased process costs. Conversely, if the C content is excessively low, the reaction temperature during high-temperature reduction is very low, meaning that C could not carburize the grain boundaries of NCM. In such cases, the NCM cannot be completely reduced, and some remains as oxide, reducing the recovery rate of the NCM alloy. If Equation 3 falls outside the lower limit of the range described above, the opposite problems may occur compared to when it falls outside the upper limit.

[0048] In one embodiment, the valuable metal recovery alloy may contain copper (Cu) in an amount of 0.02% to 5.00% by weight, based on 100% by weight of the valuable metal alloy. Specifically, the valuable metal recovery alloy may contain an amount ranging from 0.1% to 15% by weight.

[0049] If the copper content falls outside the upper limit of the range, there is a problem with process costs due to an increase in the amount of CuSO4 precipitated during leaching and solvent extraction. If the copper content falls outside the lower limit of the range, it becomes difficult to produce low-melting-point Ni-Co-Mn, and there is a problem with an increase in the amount of unreacted material.

[0050] In one embodiment, the valuable metal recovery alloy may contain aluminum (Al) in a range of 0.25 to 30% by weight. Specifically, the amount of aluminum (Al) may be 1.0 to 15.0% by weight, and more specifically, 8.0 to 9.5% by weight. If the aluminum content falls outside the upper limit of the range, there is a problem of reduced Ni and Co recovery rates in the leaching and solvent extraction steps. If the aluminum content falls outside the lower limit of the range, it is difficult to produce LiAlO2, and there is a problem of reduced Li recovery rates.

[0051] In one embodiment, the valuable metal recovery alloy may contain a carbon (C) content of 5.0% by weight or less. Specifically, it may contain 2.80 to 4.0% by weight, and more specifically, 2.96 to 3.84% by weight. By satisfying the aforementioned range of carbon content, a carburized layer is formed within the valuable metal alloy, which has the advantage of facilitating pulverization in subsequent processes and increasing the recovery rate of valuable metals.

[0052] If the carbon content falls outside the upper limit of the aforementioned range, there is a problem in that carbon separation is not easy in subsequent processes. If the carbon content falls outside the lower limit of the aforementioned range, there is a problem in that a carburized layer is difficult to form, and carbon separation from the alloy is difficult.

[0053] In one embodiment, the valuable metal alloy may include a Cu-Ni alloy. Specifically, the valuable metal alloy may include an alloy in which copper and nickel are bonded together.

[0054] In one embodiment, the valuable metal recovery alloy may include at least one of the following XRD peak intensity values: 51.5°±1.5° and 75.5°±1.5°. The aforementioned peak intensity value is indicated by the presence of a Cu-Ni alloy, which may be formed in the valuable metal recovery method when copper is melted and remains in the valuable metal alloy during the high-temperature heat treatment step, and also alloys with nickel.

[0055] Figure 1 is an SEM image of a valuable metal recovery composition that constitutes one embodiment of the present invention.

[0056] In one embodiment, the valuable metal recovery composition 100 may include a core portion 110 containing a valuable metal and a shell portion 120 disposed on at least a part of the core portion 110. Specifically, the valuable metal recovery composition 100 may consist of a metal such as Ni, Co, or a valuable metal such as Mn in the core portion 110, or an oxide containing lithium may be bonded and disposed on the core portion 110.

[0057] The core portion 110 includes a valuable metal recovery alloy, which may contain 45% by weight or more of valuable metals and the remainder being impurities, based on 100% by weight of the total composition of the alloy. The valuable metal recovery alloy may contain 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 this specification, valuable metals may mean expensive metallic components contained in the battery, and may also mean nickel, cobalt, manganese, aluminum, copper, and lithium. In one embodiment, the valuable metals may be 70% by weight or more. A detailed description of the valuable metal recovery alloy of the core portion can be found in the preceding text.

[0058] In one embodiment, the lithium in the valuable metal recovery composition 100, unlike Ni, Co, and Mn, cannot be reduced to form an alloy, but can combine with the Al component in the battery to form lithium oxide.

[0059] In one embodiment, the valuable 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.

[0060] The lithium oxide may include, for example, lithium-aluminum oxide. The lithium-aluminum oxide may also be a lithium-aluminum compound. The lithium-aluminum oxide can be formed by the lithium and aluminum contained in the composition bonding together physically or chemically to form an oxide.

[0061] In one embodiment, the lithium oxide may include LiAlO2, Li5AlO4, Li2CO3, and LiF. The LiAlO2, Li5AlO4, and Li2CO3 correspond to lithium oxides that react in the high-temperature reduction reaction process of battery waste, and LiF may be a lithium oxide detected by the electrolyte residue depending on the degree of pretreatment.

[0062] In one embodiment, the lithium compound may include at least one of the following XRD peaks with a 2θ 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°.

[0063] In one embodiment, LiAlO2 may include at least one XRD peak from among 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 may include at least one XRD peak from among 19.5 to 20.2° and 21.6 to 22.2°.

[0064] The Li2CO3 composition may contain at least one XRD peak from among 24.0 to 26.0°, 27.0 to 29.0°, 34.0 to 36.0°, and 37.0 to 39.0°. The LiF composition may contain at least one XRD peak from among 38.2 to 39.5°, 44.0 to 46.0°, 64.5 to 66.5°, and 77.77 to 79.77°.

[0065] As described above, the valuable metal recovery composition 100 has an XRD peak value for at least one of LiAlO2, Li5AlO4, Li2CO3, and LiF, and it can be confirmed that the lithium compound is attached to and arranged on the core portion containing the valuable metal.

[0066] In one embodiment, the lithium compound partially bonded to the surface of the valuable metal recovery alloy can be separated using a wet process. In another embodiment, the lithium compound can be separated from the valuable metal recovery alloy by mechanical or physical external force. In this way, not only can the valuable metal recovery alloy be recovered from the valuable metal recovery composition 100, but the lithium compound can also be separated at the same time, resulting in a high lithium recovery rate and a reduction in the amount of lithium lost.

[0067] In one embodiment, the valuable metal recovery composition 100 may contain 1 to 30% by weight of aluminum (Al). Specifically, the aluminum may contain 1.1 to 15.0% by weight. The aluminum content satisfying this range has the advantage of being able to form lithium compounds through physical or chemical bonding with lithium, and the subsequent separation of these lithium compounds can increase the lithium yield.

[0068] If the aluminum content falls outside the upper limit of the range, excessive Al2(SO4)3 formation occurs during the leaching and solvent extraction processes, leading to increased costs for the Ni and Co solvent extraction and crystallization processes, as well as a decrease in the Ni and Co recovery rate. If the aluminum content falls outside the lower limit of the range, insufficient aluminum content results in a deterioration of Li-Al-O oxide formation.

[0069] In one embodiment, the valuable metal recovery composition 100 contains aluminum (Al), and the concentration gradient of aluminum (Al) can be progressively increased from the interface between the core portion 110 and the shell portion 120 toward the shell portion 120. The reason why the concentration gradient of aluminum (Al) increases toward the shell portion 120 is that an oxide containing aluminum adheres to the core portion 110 which contains a valuable metal alloy.

[0070] In one embodiment, the valuable metal recovery method may include the steps of preparing battery crushed material, dry heat treating the crushed material, and recovering a valuable metal alloy from the heat-treated result. The method may also be for producing an alloy with a high concentration of the recovered valuable metal, and in particular, for producing an alloy with a higher concentration of the valuable metal compared to the black powder obtained through the initial crushing step. Furthermore, the recovered valuable metal alloy produced by the above manufacturing method is identical to that shown in Figure 1 above, to the extent that it is not inconsistent with the above.

[0071] The step of preparing battery shredder involves either shredding a material that will serve as the base material for the battery shredder, or preparing the shredded material itself. The base material for the battery shredder can include spent batteries such as batteries that have reached the end of their lifespan, scrap, jelly rolls, and cathode materials such as slurry that make up the waste battery, defective products generated during the manufacturing process, residues within the manufacturing process, and generated fragments, such as waste materials in the manufacturing process of lithium-ion batteries. The shredded material itself may be the shredded product itself, such as black powder.

[0072] In one embodiment, the step of preparing a battery or battery shredder in cell units may include the step of crushing a material that will serve as the base material for the battery shredder, if the base material for the battery shredder is to be crushed. The base material for the battery shredder can be crushed using a crusher. The crushing is a non-limiting example and may include applying physical or mechanical force to break up the waste battery and crushing it into a powder.

[0073] The crushing step can separate some of the larger impurities, such as aluminum (Al), copper (Cu), iron (Fe), and plastics, from the composition of the waste battery. The state in which these larger impurities have been separated is called black powder, and battery crushed material such as black powder can be produced through the crushing step.

[0074] In one embodiment, the battery fragments 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 may contain 5 to 40 wt% nickel (Ni), 1 to 20 wt% cobalt (Co), 1 to 15 wt% manganese (Mn), 0.5 to 5 wt% lithium (Li), 10 to 70 wt% carbon (C), 0.0001 to 20 wt% aluminum (Al), and 0.0001 to 20 wt% copper (Cu), with the total amount of impurities such as iron (Fe) and phosphorus (P) being less than 10 wt%. The composition of the black powder may vary depending on the ratio of nickel, cobalt, and manganese, and the nickel, cobalt, and manganese may be adjusted by the cathode material oxide of the lithium secondary battery when the lithium secondary battery is crushed.

[0075] In one embodiment, the step of crushing the material that will form the base material of the battery shredded material may be a crushing method using at least one of shear, compression, and tensile forces. Specifically, the crushing step may be performed by at least one of a hammer mill, a ball mill, and an agitated ball mill, for example. The hammer mill may perform at least one of the steps of disassembly, punching, and milling, and this is a non-limiting example, and it is clear that a variety of crushing or grinding equipment, such as industrial grinders, can be used for grinding.

[0076] In one embodiment, the particle size of the battery fragments can be within 50 mm, specifically within 30 mm. If the particle size is larger than this range, more energy will be required in the heat treatment step described later, which presents an uneconomical problem.

[0077] In one embodiment, a pretreatment step may be further included to prevent explosion or detoxify the base material of the battery shredder before the step of shredding the base material of the battery shredder. By including the pretreatment step, explosive substances such as electrolyte in the base material can be removed, and the base material, such as a waste battery, can be discharged, thereby increasing safety and improving the recovery of valuable metals and productivity when proceeding with the shredding step.

[0078] The step of dry heat treatment of the crushed material involves placing the crushed material into a heating furnace capable of raising the temperature to a high level, thereby raising the temperature of the crushed material to a level above its melting point. The step of dry heat treatment of the crushed material may involve heat treatment conditions that carry out a high-temperature reduction reaction without going through a melting step.

[0079] In one embodiment, the heat treatment conditions can be in the range of 1,150 to 1,400°C. Specifically, the range may be 1,200 to 1,300°C, and more specifically, 1,200 to 1,300°C. By performing the heat treatment within the aforementioned temperature range, copper in the battery fragments may melt and remain in the valuable metal alloy, which has the advantage of being easily separated and recovered in the subsequent magnetic separation step. Furthermore, the carbon in the battery fragments can be burned to a minimum, and the reduction reaction can be carried out with almost no carbon dioxide generation.

[0080] If the value falls outside the upper limit of the aforementioned range, there is a problem of loss due to the vaporization of lithium, and if it falls outside the lower limit of the aforementioned range, there is a problem of the sintering and reduction of the alloying elements not being able to proceed.

[0081] In one embodiment, the step of dry heat treatment of the crushed material may be carried out in a gas atmosphere of at least one of inert gas, carbon dioxide, carbon monoxide, and hydrocarbon gas. In the case of the inert gas, for example, it may include at least one of argon and nitrogen. By carrying out the reduction reaction of the crushed material in the gas atmosphere, a valuable metal recovery alloy containing valuable metals as components contained in the crushed material can be effectively recovered.

[0082] In one embodiment, a portion of the gas atmosphere may contain impurities, including residual oxygen. If the oxygen content of these impurities is high, it can combine with the components of the crushed material during the reduction reaction to form carbon dioxide, which presents a problem as it is difficult to recover the impurities by gasifying them together with lithium.

[0083] In one embodiment, the oxygen content in the dry heat treatment step may be 5% or less by volume. Specifically, the oxygen content may be 1% or less, and more specifically, 0.05% or less. Specifically, if the partial pressure of oxygen is higher than the above value, there is a problem of lithium loss and the generation of a large amount of carbon dioxide in a localized high-temperature state. If the partial pressure of oxygen is lower than the lower limit of the above range, there is a problem of reduced Li recovery rate due to deterioration of LiAlO2 formation.

[0084] In one embodiment, the dry heat treatment step may be performed in multiple stages. Specifically, the multiple stages may include a preheat treatment step and a high-temperature heat treatment step. Specifically, the high-temperature heat treatment step may be performed at a higher temperature than the preheat treatment step.

[0085] In one embodiment, the preheat treatment step may be a step of preheating the battery fragments at a temperature of 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.

[0086] In one embodiment, the preheat treatment step may be carried out at a heating rate of 5 to 15°C / min. Specifically, the preheat treatment step may be carried out at 8 to 12°C / min, and more specifically, at 9 to 11°C / min.

[0087] In one embodiment, the high-temperature heat treatment step may be performed at 900°C or higher. Specifically, the high-temperature heat treatment may involve a step of heating at a temperature higher than the melting point of copper, and may be controlled so that the copper in the valuable metal recovery composition partially melts and forms within the valuable metal alloy, and so that a carbon layer is included within the valuable metal alloy.

[0088] In one embodiment, the heating rate of the high-temperature heat treatment step may be 2.5 to 7.5°C / min. Specifically, the heating rate may be 3.5 to 6.5°C / min, and more specifically, 4 to 6°C / min.

[0089] In one embodiment, the heating rate of the high-temperature heat treatment step may be kept lower than the heating rate of the pre-heat treatment step, thereby controlling the copper in the valuable metal recovery composition to partially melt and form within the valuable metal alloy, controlling the inclusion of a carbon layer within the valuable metal alloy, and facilitating subsequent processing.

[0090] After the dry heat treatment step, a valuable metal recovery composition may be obtained, comprising a valuable metal recovery alloy in which components such as galvanic, cobalt, manganese, and lithium-containing oxides are alloyed within the crushed material, a lithium compound disposed on at least a portion of the surface of the valuable metal recovery alloy, or formed by separation from the valuable metal recovery alloy, copper, and graphite. The valuable metal recovery composition may, for example, contain aluminum (Al), manganese (Mn), lithium (Li), copper (Cu), cobalt (Co), nickel (Ni), carbon (C), and residual impurities, the detailed description relating thereto being the same as that of the valuable metal recovery composition described above, to the extent that it is not inconsistent.

[0091] The valuable metal recovery composition may contain a lithium compound, and the lithium compound may be produced by the reduction reaction. For example, the lithium compound may be lithium aluminate (2LiAlO2), and the reaction equation for this is as follows. [Reaction Equation 1] Li2O + Al2O3 = 2LiAlO2

[0092] In one embodiment, the dry heat treatment step can be modified by adding a stirring step within the heat treatment furnace. This stirring step can be performed, for example, by using a rotating body or gas to promote the reaction within the heat treatment furnace, which is a high-temperature reduction furnace, and to ensure uniformity of the internal temperature. The valuable metal recovery composition can be recovered by the reduction reaction of the black powder within the heat treatment furnace.

[0093] The step of recovering valuable metal alloys from the heat-treated product can be performed by separating the heat-treated fragments, for example, the valuable metal recovery alloy, through magnetic separation. The magnetic separation method utilizes a magnetic material to separate particles through contact with the magnetic material, and various types of magnetic separation methods can be applied.

[0094] In one embodiment, the magnetic separation may be a step of magnetically separating and recovering a valuable metal recovery alloy having magnetism with a magnetic force strength of 800 to 4,500 G. Specifically, the magnetic force strength may be 1,000 to 4,000 G, and more specifically, 2,000 to 3,000 G. When the magnetic force strength satisfies the range described above, the copper content in the recovered valuable metal alloy satisfies the above-described formulas 1 to 3, thereby improving the efficiency of the subsequent wet smelting process and reducing process costs.

[0095] In one embodiment, the magnetic separation may be performed in a dry manner. Specifically, the magnetic separation can be performed using either a dry drum-type magnetic separator or a dry conveyor belt-type magnetic separator.

[0096] In other embodiments, the magnetic separation may be performed wet. Specifically, the magnetic separation can be performed by immersing the battery fragments in a water tank or a batch containing a liquid substance, and then performing magnetic separation through a magnet. Specifically, the wet magnetic separation may be performed under conditions where the pulp density, which indicates the concentration of solids, is 10 to 50%. Specifically, the pulp density may be 20 to 40%. The wet magnetic separation has the advantage of improved sorting efficiency compared to the dry magnetic separation.

[0097] In one embodiment, a step of pre-treating the battery may be included prior to the step of preparing the battery crushed material. The pre-treating step may be a step of discharging and stabilizing the battery.

[0098] In one embodiment, the step of discharging and stabilizing the battery may be a step of saltwater discharge or electrical discharge. The step of discharging and stabilizing the battery may be a step of performing saltwater discharge or electrical discharge to lower and stabilize the voltage of the battery.

[0099] In one embodiment, the step of pre-treating the battery may include the step of freezing the battery. If the battery is directly crushed, there is a possibility of explosion and fire due to the electrolyte contained in the battery. Specifically, when a certain pressure is applied to the battery, the separator is physically crushed, a high current is formed due to a short circuit, and a spark is generated, which can cause the electrolyte to ignite and result in a fire.

[0100] The step of freezing the battery involves freezing the battery to suppress the ignition of the liquid electrolyte contained within the battery, and then carrying out the crushing process, thus preventing problems caused by electrolyte ignition.

[0101] In one embodiment, the step of freezing the battery can be carried out by cooling in the range of -150°C to -60°C. If the temperature falls outside the upper limit of the above temperature range, the voltage remaining inside the battery will not drop to 0V, which may cause a battery reaction due to a short circuit, and the electrolyte will not be completely frozen, making it inappropriate.

[0102] If the temperature falls outside the lower limit of the aforementioned temperature range, the electrolyte is sufficiently frozen, and the internal voltage of the battery drops to 0V. As a result, even if a short circuit occurs where the positive and negative electrodes are in direct contact, no battery reaction takes place. Therefore, the battery temperature does not increase, and gas generation and combustion of the electrolyte do not occur. Furthermore, because the electrolyte is frozen, the mobility of lithium ions is very low, which significantly reduces the conductivity characteristics due to lithium ion movement. Since vaporization of the electrolyte does not occur, flammable gases such as ethylene, propylene, and hydrogen are not generated.

[0103] In the step of freezing the battery, if the temperature falls outside the upper limit of the temperature range, the voltage remaining inside the battery will not drop to 0V, which may cause a short circuit and battery reaction, and the electrolyte will not be completely frozen, making it unsuitable. If the temperature falls outside the lower limit of the temperature range, a lot of energy must be supplied for freezing, which is uneconomical.

[0104] In one embodiment, the step of freezing the battery can be carried out by cooling it in a temperature range of -60 to -20°C under a vacuum atmosphere of 100 torr or less. The step of freezing the battery can be carried out in the temperature range that suppresses the vaporization of the electrolyte. The vacuum atmosphere may be, for example, an inert gas, carbon dioxide, nitrogen, water, or a combination thereof.

[0105] Since the process is carried out under a vacuum atmosphere with pressure below 100 torr, the oxygen supply is suppressed, preventing the electrolyte from reacting with oxygen, thus preventing explosions, suppressing the vaporization of the electrolyte, and preventing the generation of flammable gases such as ethylene, propylene, and hydrogen.

[0106] In the step of freezing the battery, if the procedure is carried out in an air atmosphere or under a pressure exceeding 100 torr, some voltage may remain in the battery. Since the electrolyte is not frozen at a temperature range of -60 to -20°C, there is a problem that the electrolyte may vaporize and explode due to sparks generated when a short circuit occurs due to the remaining voltage.

[0107] To further illustrate the present invention, embodiments of the present invention are described below. The embodiments described below are merely one example of the present invention, and the present invention is not limited to these embodiments.

[0108] <Example of experiment> <Example 1> Steps to prepare the battery 2750g of NCM622 batteries were prepared, and the content ratio of the NCM622 batteries is as shown in Table 1 below.

[0109] [Table 1]

[0110] Battery destruction step It is preferable to freeze the waste battery at -30°C or below, then crush it, or discharge it under saltwater discharge or electrical discharge conditions, and then crush the waste battery using a shredder under atmospheric or inert gas conditions so that the longest length of the horizontal and vertical dimensions is 100 mm or less. Specifically, an NCM622 battery with an SOC of 40% or less was frozen at -70°C for 24 hours or more, and then crushed in a nitrogen atmosphere using a shredder so that the longest diameter was 100 mm or less.

[0111] High-temperature heat treatment step After obtaining the valuable metal recovery composition using the method described above, the crushed battery fragments were heat-treated at 1,250°C under an oxygen partial pressure of 0.5% to perform a reduction process. During this heat treatment reduction, an inert gas was purged to maintain the oxygen concentration in the furnace at 0.5% or less, and the temperature was increased at 10°C / min from room temperature to 900°C, and then at 5°C / min from 900°C to 1,250°C. The inert gas was stopped once the oxygen partial pressure in the furnace was continuously maintained at 0.5% or less. After maintaining the temperature at 1,250°C for more than 3 hours, the sample was cooled at a cooling rate of 20°C / min or more. The valuable metal recovery composition was obtained through the above reduction process.

[0112] Figure 1 is an SEM image of a valuable metal recovery composition according to one embodiment of the present invention.

[0113] Figures 2a and 2b show the XRD analysis results of a valuable metal recovery composition according to one embodiment.

[0114] Referring to Figures 1, 2a, and 2b, it can be seen that the valuable metal recovery composition has a lithium compound, specifically lithium oxide, bonded and arranged on a valuable metal recovery alloy. Such a structure may also be formed by carrying out the reduction process described above.

[0115] Figure 3 shows the results of XRD analysis on the state change of Cu in a valuable metal recovery composition according to one embodiment.

[0116] Referring to Figure 3, the state change of molten Cu in the silver composition for valuable metal recovery 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 remains molten within the NCM alloy, and the amount of molten Cu within the NCM alloy can be controlled by the reduction temperature.

[0117] Figures 4a and 4b show the melting process of copper foil (Cu foil) in the heat treatment step of battery fragments according to the present invention.

[0118] Figure 4a shows the state of the copper foil (Cu foil) before it melts, and Figure 4b shows the state after the copper foil has melted. Referring to Figures 4a and 4b, it can be confirmed that copper melts at 1,050°C, and that the light-colored copper areas in Figure 4a have completely disappeared in Figure 4b.

[0119] Examples 1 and Comparative Examples 1-3 are experimental results for reactants that were reduced at high temperature under high-temperature heat treatment conditions ranging from 900 to 1500°C in an atmosphere with an oxygen concentration of 0.5% or less.

[0120] The high-temperature reduction reaction product was separated using a 100 μm sieve. Reaction material smaller than 100 μm, which mainly consists of carbon and metallic Cu, was separated separately. Reaction material larger than 100 μm was separated into magnetic and non-magnetic products using a magnetic separator with a magnetic force of 3000 G, and the ratio of each component was then analyzed. The components of the fine powder smaller than 100 μm 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 a Co and Mn content of 2% or less.

[0121] <Comparative Example 1> The procedure was the same as in Example 1, except that the high-temperature heat treatment step was performed at 1,100°C.

[0122] <Comparative Example 2> The procedure was the same as in Example 1, except that the high-temperature heat treatment step was performed at 1,500°C.

[0123] <Comparative Example 3> The procedure was the same as in Example 1, except that the high-temperature heat treatment step was performed at 900°C.

[0124] <Evaluation Example 1> - Evaluation of the components of a valuable metal recovery composition Table 2 below shows the components obtained when a valuable metal recovery composition produced by a high-temperature heat treatment process is separated by magnetic force.

[0125] The following components were measured using ICP-OES and C / S analyzers.

[0126] [Table 2]

[0127] Examining the examples in Table 2, compared to the component ratios of the NCM622 battery in Table 1, the Cu / Ni, Cu / Mn, and Cu / C content ratios increase sharply. During the high-temperature reduction process, oxygen and carbon in the NCM cathode material are consumed to convert to CO and CO2 gases. The Cu / C content ratio of the magnetic products increases rapidly from 44% to 118% due to the carbon and some of the carbon that burns, and the non-magnetic products also increase to 163%. The Cu / Ni and Cu / Mn ratios of the magnetic products are 12.6% and 41.0%, respectively, which is about half of what is shown in Table 1. This is because the NCM oxide cathode material is reduced to metal and almost completely separated as magnetic products. Consequently, the Cu / Ni and Cu / Mn ratios of the non-magnetic products increase to several thousand percent. Comparative Example 1 shows the results of magnetic separation of a material reacted at 1,100°C, slightly higher than the 1,050°C at which Cu melts during the high-temperature reduction reaction. It can be seen that the weight percentage of valuable metals recovered as magnetic products is somewhat lower compared to Example 1. This is because the reaction rate of the reduction reaction is highly temperature-dependent, increasing as the temperature rises. Therefore, the cathode material was not completely reduced compared to Example 1, and some remained in oxide form.

[0128] Comparative Example 2 involved a reaction at a high temperature of 1,500°C, where carbon was almost completely burned and did not remain in the magnetic or non-magnetic products. Furthermore, because the reaction occurred 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, resulting in the highest weight percentage of NCM in the magnetic products. However, almost all of the Li volatilized and could not be recovered as a magnetic product, with only a trace amount being recovered in the slag-form non-magnetic product.

[0129] Comparative Example 3 involved a reaction at 900°C, a temperature lower than the melting point of Cu (1,050°C), followed by separation of magnetic and non-magnetic products. Generally, reduction reactions with carbon become more active at temperatures higher than the temperature at which the Boudoir reaction occurs thermodynamically. Since Comparative Example 3 is at a temperature similar to the Boudoir reaction temperature, some of the cathode material is reduced and recovered as magnetic products, but only at a significantly lower level compared to Example 1. Therefore, the Cu / Ni ratio, Cu / Mn ratio, and Cu / C ratio are shown to be very low compared to the examples. In conclusion, high-temperature reduction reactions need to be carried out at an intermediate temperature range, higher than 1100°C and lower than 1500°C.

[0130] <Evaluation Example 2> - Evaluation of the components of valuable metal alloys Evaluation of the components of valuable metal recovery compositions This shows the results of magnetic separation of the reaction product produced in a dry heat treatment step with a high-temperature reduction reaction temperature of 1,300°C. At this time, the ratio of the components of the magnetic product to each component was compared according to the strength of the magnetic force.

[0131] <Example 2> A valuable metal recovery composition was produced in the same manner as in Example 1, except that the high-temperature reduction reaction temperature was set to 1,300°C in the dry heat treatment step. Subsequently, the produced valuable metal recovery composition was magnetically separated with a magnetic force of 1,000 G to recover the magnetic material.

[0132] <Example 3> The procedure was the same as in Example 2, except that the valuable metal recovery composition was magnetically separated at a magnetic force strength of 2,000 G to recover the magnetic material.

[0133] <Example 4> The procedure was the same as in Example 2, except that the valuable metal recovery composition was magnetically separated at a magnetic force strength of 3,000 G to recover the magnetic material.

[0134] <Comparative Example 4> The procedure was the same as in Example 2, except that the valuable metal recovery composition was magnetically separated at a magnetic force strength of 500G to recover the magnetic material.

[0135] <Comparative Example 5> The procedure was the same as in Example 2, except that the valuable metal recovery composition was magnetically separated at a magnetic force strength of 5,000 G to recover the magnetic material.

[0136] Table 3 below shows the components of magnetic and non-magnetic materials in the valuable metal recovery alloy when the valuable metal recovery composition is separated by magnetic force according to the strength of the magnetic field. The magnetic separation method used was as follows.

[0137] Magnetic separation method: Using a drum-type wet magnetic separator manufactured by Taiho Magnetic Co., Ltd., ore separation experiments were conducted at different magnetic strengths.

[0138] [Table 3]

[0139] As can be seen in Table 3 above, in the examples where the magnetic force is in the range of 1000 to 3000 G, the Cu / Ni ratio of the magnetic product changes within a narrow range of 10-15%, the Cu / Mn ratio within 40-50%, and the Cu / C ratio within 100-150%. However, in the comparative example with a lower magnetic force of 500 G, the Cu / Ni ratio of the magnetic product is 18.1%, the Cu / Mn ratio is 59.8%, and the Cu / C ratio is 212%, showing a very rapid increase. It can also be seen that a considerable amount of Li and NCM valuable metals remained in the non-magnetic product at 500 G and could not be recovered as magnetic products. Comparative Example 5 is the experimental result for a very strong magnetic force of 5000 G. The Cu / Ni ratio and Cu / Mn ratio are similar to the ratio range of the examples, but carbon, which is a non-magnetic material, was recovered as a magnetic product, and the Cu / C ratio rose to 70%, which is a significant decrease compared to the range of the examples. This indicates that if the magnetic force strength during magnetic separation is excessively strong beyond the range presented in this invention, even non-magnetic substances will be recovered as magnetic products, thus reducing the effectiveness of magnetic separation in separating valuable metals from carbon.

[0140] The present invention is not limited to the embodiments described above and can be manufactured in a variety of different forms. Those with ordinary skill in the art to which the present invention pertains will understand that the invention can be implemented in other specific forms without altering the technical idea or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting.

Claims

1. Based on 100% by weight of the total composition of the alloy, Valuable metals make up 45% by weight or more, with the remainder being impurities. A valuable metal recovery alloy that satisfies Equation 1 below. <Formula 1> 5.0≦[Cu] / [Ni]≦15.0% (In formula 1 above, [Cu] and [Ni] represent the Cu and Ni content in the valuable metal recovery alloy, respectively.)

2. A valuable metal recovery alloy according to claim 1, satisfying the following formula 2. <Formula 2> 30.0≦[Cu] / [Mn]≦55.0% (In the above formula 2, [Cu] and [Mn] represent the Cu and Mn content in the valuable metal recovery alloy, respectively.)

3. A valuable metal recovery alloy according to claim 1, satisfying the following formula 3. <Formula 3> 50.0≦[Cu] / [C]≦200.0% (In the above formula 3, [Cu] and [C] represent the Cu and C content in the valuable metal recovery alloy, respectively.)

4. A valuable metal recovery alloy according to claim 1, comprising a CuNi alloy.

5. The valuable metal recovery alloy according to claim 1, wherein the XRD peak value has at least one diffraction peak among 2θ = 44° ± 1°, 2θ = 51.5° ± 1.5°, and 2θ = 75.5° ± 1.5°.

6. The valuable metal recovery alloy according to claim 1, comprising copper (Cu) in a content of 0.02 to 5.00% by weight or less, based on 100% by weight of the valuable metal recovery alloy.

7. The valuable metal recovery composition according to claim 1, comprising carbon (C) in an amount of 5.0% by weight or less, based on 100% by weight of the valuable metal recovery alloy.

8. Steps to prepare individual battery cells or battery fragments; A step of dry heat treatment at a temperature range of 1,150 to 1,400°C without going through the melting step of the battery or the crushed material; and A method for recovering valuable metals, comprising the step of recovering a valuable metal recovery alloy having magnetism with a magnetic force of 800 to 4,500 G from the dry heat-treated result by magnetic separation.

9. The method for recovering valuable metals according to claim 8, wherein the dry heat treatment step is performed in an atmosphere with an oxygen content of 5% or less.

10. The dry heat treatment step includes a multi-stage step, The method for recovering valuable metals according to claim 8, wherein the multi-stage steps include a preheat treatment step and a high-temperature heat treatment step performed at a higher temperature than the preheat treatment step.

11. The aforementioned preheat treatment step is carried out at a temperature of 900°C or lower. The method for recovering valuable metals according to claim 8, wherein the heating rate of the preheat treatment step is 5 to 15°C / min.

12. The aforementioned high-temperature heat treatment step is performed at 900°C or higher. The method for recovering valuable metals according to claim 8, wherein the heating rate of the high-temperature heat treatment step is 2.5 to 7.5°C / min.

13. The process after the aforementioned high-temperature heat treatment step includes a cooling step, The cooling step is carried out at a cooling rate of 20°C / min or more. The method for recovering valuable metals according to claim 8, wherein the high-temperature heat treatment step is performed at 900°C or higher.

14. The method for recovering valuable metals according to claim 8, wherein the step of recovering the valuable metal recovery alloy by magnetic separation is performed in a wet manner.

15. The method for recovering valuable metals according to claim 8, wherein the step of recovering the valuable metal recovery alloy by magnetic separation is performed in a range where the mineral solution concentration, which indicates the concentration of solids, is 10 to 50%.

16. The method for recovering valuable metals according to claim 8, wherein the result obtained from the dry heat treatment step separates the lithium compound bonded to a portion of the surface of the valuable metal recovery alloy by external force.

17. The method for recovering valuable metals according to claim 8, wherein the step of preparing the cell-unit battery or battery shredder includes a step of pre-treating the cell-unit battery or battery shredder.

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