Method of recovering valuable metals

Abstract

The present invention relates to a method for recovering valuable metals, the method comprising: a step of dry heat-treating materials obtained from waste batteries to obtain a valuable metal recovery composition; and a pulverization step of separating a first metal material containing valuable metals and a second metal material containing lithium disposed on at least a partial region of the surface of the metal material from the valuable metal recovery composition, wherein the pulverization step is performed under wet conditions.

Description

Method for recovering valuable metals

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

[0002] Batteries are rapidly increasing in capacity, not only in electronic devices like smartphones and mobile devices, but also in electric vehicles. Demand for these batteries is expected to grow further as electric vehicles become a growing next-generation mode of transportation.

[0003] Since the above electric vehicles require batteries with large electric capacities, they are installed and used in electric vehicles in the form of multiple battery cells, modules comprising multiple battery cells, and packs comprising multiple modules. As the use of electric vehicles rapidly increases, the amount of discarded batteries used in such vehicles is also increasing.

[0004] The above battery may be used by mixing copper (Cu) and aluminum (Al) used as current collectors, lithium (Li), nickel (Ni), cobalt (Co), and manganese (Mn) containing oxides forming a cathode, graphite forming an anode, a separator separating the cathode and the anode, an electrolyte injected into the separator, and a carbonate organic material such as propylene carbonate, and the salt may be, for example, LiPF6 (Lithium hexafluorophosphate).

[0005] Recently, the disposal of lithium-ion batteries, such as those used in electric vehicles, has become a global concern. These lithium-ion batteries contain organic solvents, potentially causing fires, explosive materials, and heavy metals such as nickel, cobalt, manganese, and iron. Among these, nickel, cobalt, manganese, and lithium are valuable metals, possessing both scarcity and utility. Therefore, the recovery and recycling processes for these discarded lithium-ion batteries are becoming crucial issues.

[0006] Lithium secondary batteries are composed of copper (Cu) and aluminum (Al) used as current collectors, lithium (Li), nickel (Ni), cobalt (Co), and manganese (Mn) forming the cathode, and graphite (C) forming the anode. The aforementioned components exist in a metallic form within the current collector to ensure electrical conductivity, and in the cathode active material to ensure chemical stability in the form of metal composite oxides.

[0007] For recycling, the above lithium secondary battery is subjected to a crushing and sorting process to extract black powder containing a mixture of positive and negative electrode materials. The black powder includes, for example, oxides of nickel, cobalt, manganese, lithium, aluminum, and oxygen as positive electrode materials, graphite and mixtures thereof as negative electrode materials, and impurities such as aluminum and copper. Among the reactants sorted through the sorting process, the NCM compound is magnetic and is recovered by magnetic sorting. However, the NCM compound is produced in a state where an oxide containing lithium is filmed on the NCM core, which lowers the quality of the NCM and lowers the Li recovery rate.

[0008] The technical problem to be solved by the present invention is to provide a method for recovering a valuable metal, which comprises a valuable metal alloy obtained through a dry heat treatment process of a spent battery and which includes a valuable metal of Ni, Co, and Mn, and an oxide containing lithium disposed on the surface of the valuable metal alloy, thereby improving the grade of the valuable metal and improving the recovery rate of Li, by selectively removing the oxide containing lithium from the valuable metal recovery composition.

[0009] This application claims priority to Republic of Korea Patent Application No. 10-2024-0103238, filed August 2, 2024, the entire contents of which are incorporated herein by reference.

[0010] According to one embodiment of the present invention, a method for recovering valuable metals comprises the steps of dry heat treating a waste battery to obtain a composition for recovering valuable metals, and a crushing step for separating a first metal material including a valuable metal from the composition for recovering valuable metals and a second metal material disposed on at least a portion of a surface of the metal material and including lithium, wherein the crushing step can be performed under wet conditions.

[0011] In one embodiment, the pulp density under the wet conditions may be 30 to 55%. In one embodiment, the crushing step is performed by a vertical stirring mill (Attrition Mill), and the rpm of the vertical stirring mill under the wet conditions may be 250 to 1,000 rpm.

[0012] In one embodiment, the grinding time under the wet conditions may be 10 to 60 minutes. In one embodiment, the grinding step is performed by a vertical stirring grinder (Attrition Mill), and the size of the grinding media of the grinder may be 4 mm or more.

[0013] In one embodiment, between the step of obtaining the valuable metal recovery composition and the step of crushing, a step of particle-separating the valuable metal recovery composition into coarse particles and fine particles may be included. In one embodiment, a first magnetic separation step may be included for separating a magnetic material from the fine particles separated through the particle-separating step.

[0014] In one embodiment, a second magnetic separation step may be included to separate magnetic materials from the resultant product of the crushing step. In one embodiment, the first magnetic separation step and the second magnetic separation step may be performed at a magnetic force of 1,000 Gauss or greater.

[0015] In one embodiment, between the step of obtaining the valuable metal recovery composition and the step of crushing, a step of particle-separating the valuable metal recovery composition into coarse particles and fine particles may be included. In one embodiment, a first magnetic separation step may be included for separating a magnetic material from the fine particles separated through the particle-separating step.

[0016] In one embodiment, a second magnetic separation step may be included to separate magnetic materials from the resultant product of the crushing step. In one embodiment, the first magnetic separation step and the second magnetic separation step may be performed at a magnetic force of 1,000 Gauss or greater.

[0017] In one embodiment, the first magnetic separation step and the second magnetic separation step may include a water spraying step. In one embodiment, the water spraying step may spray water in the opposite direction of the drum from which the magnetic material is recovered in the first magnetic separation step and the second magnetic separation step.

[0018] In one embodiment, in the step of obtaining the composition for recovering valuable metals, the heat treatment temperature may be performed at 1,100° C. or higher. In one embodiment, the composition for recovering valuable metals obtained by dry heat treating the material obtained from the spent battery may include a core portion of a first metal material including at least one of nickel, cobalt, and manganese, and a shell portion disposed on at least a portion of the surface of the core portion, and disposed in combination with lithium disposed on the surface of the core portion.

[0019] According to another embodiment of the present invention, a method for recovering valuable metals includes a step of dry heat treating a material obtained from a spent battery to obtain a composition for recovering valuable metals, and a crushing step for separating a first metal material including valuable metals from the composition for recovering valuable metals and a second metal material disposed on at least a portion of a surface of the metal material and including lithium, wherein the first metal material that has undergone the crushing step may include 0.50 to 1.00 wt% of lithium (Li) based on 100 wt% of the first metal material.

[0020] In one embodiment, the first metal material may include 0.1 to 10 wt% of aluminum (Al) based on 100 wt% of the first metal material. In one embodiment, the average particle diameter (D50) of the first metal material may be 50 to 1,000 μm. In one embodiment, the average particle diameter (D50) of the second metal material may be 50 to 500 μm.

[0021] According to one embodiment of the present invention, a method for recovering valuable metals includes a wet grinding process, selectively removing an oxide containing lithium from a composition for recovering valuable metals, which is obtained through a dry heat treatment process of a spent battery and includes a valuable metal alloy containing nickel, cobalt, and manganese, and an oxide containing lithium disposed on the surface of the valuable metal alloy, thereby improving the quality of the valuable metal and improving the recovery rate of lithium.

[0022] Figure 1 is a SEM photograph of a composition for recovering valuable metals obtained by high-temperature reduction treatment of battery shreds of the present invention.

[0023] The terms first, second, and third, etc., are used to describe, but are not limited to, various parts, components, regions, layers, and / or sections. These terms are used only to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, a first part, component, region, layer, or section described below may be referred to as a second part, component, region, layer, or section without departing from the scope of the present invention.

[0024] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present invention. As used herein, the singular forms "singular" and "comprising" include plural forms as well, unless the context clearly dictates otherwise. The word "comprising" as used herein specifies a particular feature, region, integer, step, operation, element, and / or component, but does not exclude the presence or addition of other features, regions, integers, steps, operations, elements, and / or components.

[0025] When a part is referred to as being "on" or "over" another part, it can be directly on or over the other part, or there may be other parts intervening. Conversely, when a part is referred to as being "directly on" another part, there are no other parts intervening.

[0026] Although not defined otherwise, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or overly formal unless otherwise defined.

[0027] According to one embodiment of the present invention, a method for recovering valuable metals includes a step of dry heat treating a waste battery to obtain a composition for recovering valuable metals, and a pulverizing step for separating a first metal material including a valuable metal from the composition for recovering valuable metals and a second metal material including lithium disposed on at least a portion of a surface of the metal material. Specifically, the method for recovering valuable metals may be a method for increasing the recovery rate of valuable metals and minimizing the loss of lithium by wet-pulverizing the first metal material including a valuable metal from the composition for recovering valuable metals obtained by dry heat treating a waste battery and the second metal material disposed on the surface of the first metal material.

[0028] The above-mentioned waste battery may mean at least one of a cell including a lithium ion battery, a pack including a plurality of the cells, and a module including a plurality of the packs. Specifically, the above-mentioned waste battery may include waste batteries such as batteries that have reached the end of their lifespan, scrap, jelly rolls, positive electrode materials such as slurry, defective products generated during the manufacturing process, residues within the manufacturing process, and generated debris.

[0029] In one embodiment, the waste battery may be waste battery shredder. Specifically, the waste battery shredder may be prepared by shredding the waste battery, or the shredder may refer to the material itself.

[0030] Specifically, the method for recovering valuable metals may include a step of preparing the waste battery before the step of dry heat treating the waste battery to obtain a composition for recovering valuable metals. More specifically, the step of preparing the waste battery may include a step of crushing the waste battery. The step of crushing the waste battery may be performed by crushing the waste battery using a device such as a crusher to obtain a pulverized product. The crushing may include, but is not limited to, crushing the waste battery by applying physical or mechanical force and pulverizing the waste battery into fine powder.

[0031] In one embodiment, the step of crushing the battery may be a crushing method using at least one of shear, compression, and tensile force. Specifically, the step of crushing may be crushed by, for example, at least one of a hammer mill, a ball mill, and a stirred ball mill. The hammer mill may perform at least one of disintegration, punching, and milling, and various types of crushing or crushing devices, for example, an industrial crusher, may be utilized as non-limiting examples. The step of crushing the battery may separate some large impurities, such as aluminum (Al), copper (Cu), iron (Fe), and plastic, from the components included in the battery.

[0032] In one embodiment, the step of shredding the battery may be performed so that the size of the battery shreds is 100 mm or less. Specifically, the size of the battery shreds may be 80 mm or less, and more specifically, 50 mm or less. When the size of the battery shreds satisfies the aforementioned range, there is an advantage of excellent process energy efficiency, and when the size of the battery shreds is larger than the aforementioned range, there is an uneconomical problem due to excessive energy supply in the heat treatment step.

[0033] In one embodiment, prior to the step of shredding the battery, a pretreatment step may be included to prevent explosion or render harmless the parent material of the battery shreds. By including the pretreatment step, the method for processing spent batteries can remove potentially explosive substances, such as electrolytes, within the parent material, and discharge the parent material, such as spent batteries, thereby enhancing stability and increasing the recovery and productivity of valuable metals during the shredding step.

[0034] The step of dry heat treating the waste battery to obtain a composition for recovering valuable metals may be a step of putting the waste battery, for example, waste battery shreds, into a high-temperature reduction furnace capable of raising the temperature to a high temperature to perform a high-temperature reduction reaction on the waste battery shreds. To perform the dry heat treatment step, the waste battery shreds may be filled into the high-temperature reduction furnace, and then the temperature of the high-temperature reduction furnace may be raised to apply heat to the waste battery shreds.

[0035] The composition for recovering valuable metals obtained by dry heat treating the spent battery may include a valuable metal and a lithium compound. At least a portion of the composition for recovering valuable metals may maintain a form in which the valuable metal and the lithium compound are combined, or the valuable metal and the lithium compound may be separated from each other and maintain independent forms, or the composition may include a combination of the aforementioned forms. The composition for recovering valuable metals may include graphite, and the graphite may be derived from a negative electrode within the spent battery.

[0036] In one embodiment, at least a portion of the valuable metal recovery composition may comprise a first metal material comprising a valuable metal and a second metal material comprising lithium, the second metal material being disposed on at least a portion of a surface of the first metal material. Specifically, at least a portion of the valuable metal recovery composition may comprise a core-shell alloy comprising a core portion comprising an alloy comprising a valuable metal and a shell portion disposed on at least a portion of a surface of the core portion.

[0037] The first metal material may be a metal including at least one of valuable metals such as lithium, nickel, cobalt, and manganese, for example, and the second metal material may be a metal including lithium, a lithium compound, and specifically, the lithium compound may be a material such as lithium-aluminum oxide or lithium fluoride. The lithium-aluminum oxide may be a lithium-aluminum compound, and the lithium-aluminum oxide may be a material in which lithium and aluminum are combined into an oxide through a physical or chemical bond with each other.

[0038] In one embodiment, the dry heat treatment step may be performed at a temperature higher than the temperature at which the oxide containing the valuable metal reaches equilibrium with each other and reduction begins. Specifically, the dry heat treatment step may be performed at a temperature higher than the temperature at which the oxide containing the valuable metal and the metallic liquid reach equilibrium with each other and reduction begins.

[0039] In one embodiment, the dry heat treatment step may be performed at a lower temperature than the boiling point of lithium oxide. Specifically, the lithium oxide may refer to Li2O or LiAlO2. The reduction reaction of the oxide may be divided into a direct reduction reaction in which the oxide is reduced by direct contact with carbon (C) to produce carbon monoxide (CO) or carbon dioxide (CO2), and an indirect reduction reaction in which carbon monoxide injected into a reduction furnace or produced by a reaction reduces the oxide, and the indirect reduction reaction may be performed under the assumption that graphite is present.

[0040] In one embodiment, the dry heat treatment step may be performed at a temperature range of 1,100 to 1,500°C. Specifically, the temperature range may be 1,150 to 1,450°C, and more specifically, 1,100 to 1,355°C. By performing the heat treatment within the above temperature range, it is possible to maintain a reducing atmosphere in which the graphite is treated at a high temperature but is not completely combusted.

[0041] 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 proceeding. In this way, the carbon in the crushed material can be burned to a minimum within the above temperature range to perform a reduction reaction with almost no carbon dioxide generation, and the first metal material and the second metal material in the composition for recovering valuable metals can be alloyed in a core-shell shape, making separation easy in a subsequent process.

[0042] In one embodiment, the dry heat treatment step may be performed in a gas atmosphere of at least one of an inert gas, carbon dioxide (CO2), carbon monoxide (CO), and a hydrocarbon gas. The gas atmosphere may be an atmosphere introduced through the gaps between the spent battery fragments filled in a high-temperature reduction furnace, which is replaced with the aforementioned gas.

[0043] In the case of the above inert gas, it may include, for example, at least one of argon (Ar), hydrogen (H2), and nitrogen (H2). The above hydrocarbon gas refers to an organic compound composed only of carbon (C) and hydrogen (H), and may refer to a compound such as methane (CH4). By performing the dry heat treatment step in the above-described gas atmosphere, it is possible to prevent the problem of the quality of the recovered valuable metal being lowered by external gases such as impurities.

[0044] In one embodiment, the gaseous atmosphere may include oxygen (O2). In one embodiment, the partial pressure of the oxygen in the gaseous atmosphere may be supplied above the partial pressure of oxygen at which lithium oxide in the battery shredder is reduced. Specifically, the oxygen may be included in the gaseous atmosphere during the dry heat treatment step, thereby reacting with graphite in the battery shredder to form carbon monoxide.

[0045] In one embodiment, the oxygen content may be 6.0 vol% or less based on 100 vol% of the total volume of the high temperature reduction furnace. Specifically, the oxygen content may be 2.1 vol% or less. More specifically, the oxygen content may be 0.1 to 2.1 vol%, and even more specifically, 0.4 to 2.1 vol%.

[0046] When the content of the oxygen in the gas atmosphere satisfies the above-described range, lithium and aluminum are alloyed in the form of an oxide to form a lithium compound, and the lithium compound is melt-bonded with lithium on the surface of a first metal material including nickel, cobalt, and manganese, so that a core-shell structured valuable metal recovery composition can be easily formed.

[0047] In one embodiment, the step of obtaining the composition for recovering valuable metals may include a step of separating the composition for recovering valuable metals into coarse particles with large particles and fine particles with small particles based on particle size. The step of separating the particles by size or diameter may refer to a method of separating the particles by using a sieve, for example.

[0048] Specifically, the particle size separation step may involve separating reactants with small particle sizes through a sieve having a predetermined particle size, thereby performing subsequent processes. The coarse particles that have undergone the particle size separation step may be directly input into the leaching process. The fine particles that have undergone the particle size separation step may undergo an additional separation process to increase the recovery rate of valuable metals.

[0049] In one embodiment, the particle size separation step can separate coarse particles having a particle size larger than the particle size range of 1 to 2 mm through a sieve, and fine particles having a particle size smaller than the particle size range. The coarse particles contain a large amount of valuable metals, so they can be directly fed into a leaching process to recover the valuable metals. In contrast, the fine particles have a particle size similar to that of carbon, so they can be separated together with the carbon. If the fine particles are separated together with the carbon, the valuable metals in the fine particles may be separated together with the carbon, which may cause a problem of lowering the recovery rate of the valuable metals. Therefore, the fine particles can be subjected to an additional screening process to improve the recovery rate of the valuable metals throughout the process.

[0050] In one embodiment, the method for recovering valuable metals may include a first magnetic separation step for separating magnetic substances from the fine particles separated through the particle size separation step. The first magnetic separation step may be to perform magnetic separation on the fine particles separated by particle size separation of the valuable metal recovery composition. Specifically, the magnetic separation may separate particles through contact with a magnetic substance using the magnetic substance, and various types of magnetic separation methods may be applied. Specifically, the first magnetic separation step may separate magnetic substances having magnetism and non-magnetism having non-magnetism.

[0051] The magnetic material may be a material having magnetism, including nickel, cobalt, and manganese, which are precious metals. Specifically, the magnetic material may include lithium or a lithium compound combined with the aforementioned precious metal. The non-magnetic material may include at least one of a compound including lithium that is not combined with a precious metal in the first magnetic separation step and a graphite material including carbon.

[0052] In one embodiment, the first magnetic separation step may be performed at a magnetic force of 1,000 Gauss or greater. Specifically, the first magnetic separation step may be performed within a range of 1,000 to 5,000 Gauss, and more specifically, within a range of 2,000 to 3,000 Gauss. By performing the first magnetic separation step within the above range, there is an advantage in that valuable metals can be efficiently separated.

[0053] If the first magnetic separation step is performed at a magnetic range that is outside the upper limit of the above range, the recovery rate increases because even trace amounts of valuable metals are recovered, but the grade of the recovered valuable metals is lowered and the amount of impurities such as graphite and copper mixed in increases, which lowers the process efficiency in the subsequent wet refining process and causes an uneconomical problem. If the first magnetic separation step is performed at a magnetic range that is outside the lower limit of the above range, the recovery rate of valuable metals is lowered, which causes an increase in the loss of valuable metals such as nickel, cobalt, and manganese.

[0054] In one embodiment, the first magnetic separation step may include a water spraying step. Specifically, the first magnetic separation step may be performed by spraying water when separating the magnetic and non-magnetic materials in the metal recovery composition. More specifically, the water may be sprayed in the opposite direction of the drum in which the magnetic material is recovered, thereby preventing the entrapment of the non-magnetic material and efficiently collecting the magnetic material.

[0055] In one embodiment, the pulverization step of separating the first metal material including the valuable metal and the second metal material including lithium disposed on at least a portion of the surface of the metal material among the magnetic body that has undergone the first magnetic separation step, specifically the valuable metal recovery composition, may be performed under wet conditions. The pulverization step may be a step of applying an external force to a core-shell alloy among the valuable metal recovery composition to separate the shell portion, which is a lithium compound including lithium, from the core portion including the valuable metal.

[0056] The above grinding step can be performed under wet conditions, and the wet conditions can be grinding the core-shell shaped alloy using a vertical stirring ball mill.

[0057] Specifically, the crushing step may be performed in an environment containing a pulp. The pulp may refer to a mixture of an NCM compound containing nickel, cobalt, and manganese, which are valuable metals; a lithium compound containing lithium; and graphite. For example, the pulp may refer to a mixture of the aforementioned materials in a fluid state mixed with a solution.

[0058] In one embodiment, the pulp density under the above wet conditions may be 30 to 55%. Specifically, the pulp density may be 30 to 50%. The pulp density may refer to the weight percentage of the high-temperature reduction reactant recovered from the battery shredder through a high-temperature reduction reaction to the sum of the weights of water and the high-temperature reduction reactant (weight of the high-temperature reduction reactant / (sum of the weights of the water and the high-temperature reduction reactant) × 100). When the pulp density satisfies the above-described range, the core-shell alloy in the composition for recovering valuable metals can be easily separated into a core portion and a shell portion in the wet pulverization step.

[0059] If the above-mentioned concentration of the slurry exceeds the upper limit of the aforementioned range, there is a problem that the pulverizing ability is weakened due to absorption of all moisture in the slurry due to an increase in the specific surface area caused by over-pulverization. If the above-mentioned concentration of the slurry exceeds the lower limit of the aforementioned range, there is a problem that the pulverizing ability is weakened due to a decrease in the appropriate ratio of the sample to the ball.

[0060] In one embodiment, the crushing step may be performed by a vertical stirring crusher (Attrition Mill), and the rpm of the vertical stirring crusher under the wet condition may be 250 to 1,000 rpm. More specifically, the rpm may be 300 to 700 rpm. The rpm may refer to a rotation speed of the stirring blade of the vertical stirring crusher of 300 to 700 rotations per minute. When the rotation speed satisfies the above-mentioned range, the core-shell shaped alloy in the valuable metal recovery composition can be easily separated into a core portion and a shell portion in the wet crushing step.

[0061] If the rotation speed exceeds the upper limit of the aforementioned range, there is a problem that over-crushing occurs, resulting in enlarged particle sizes of the nickel, cobalt, and manganese (NCM) metal components due to ductility. If the rotation speed exceeds the lower limit of the aforementioned range, there is a problem that the pulverizing performance is reduced due to reduced friction between the sample and the ball.

[0062] In one embodiment, the grinding step may have a grinding time of 10 to 60 minutes under the wet conditions. Specifically, the grinding time may refer to the total time for grinding the valuable metal recovery composition using the vertical stirring grinder. By satisfying the grinding time within the above-described range, the core-shell alloy in the valuable metal recovery composition can be easily separated into a core portion and a shell portion in the wet grinding step.

[0063] If the above-mentioned grinding time exceeds the upper limit of the aforementioned range, there is a problem that the metal component of the NCM becomes ductile and the particle size increases due to over-grinding, and the vertical stirring ball mill deteriorates, causing the sample to deteriorate. If the above-mentioned grinding time exceeds the lower limit of the aforementioned range, there is a problem that the grinding time is reduced, resulting in a decrease in grinding performance.

[0064] In one embodiment, the size of the grinding medium of the grinder may be 4 mm or more. Specifically, the grinding medium refers to a component that directly grinds the material to be ground in the grinder, and the size of the grinding medium may refer to the diameter of the grinding medium. Specifically, the grinding medium may be a component such as a zirconia ball, for example.

[0065] The size of the above grinding medium may be 5 mm or more, specifically, 5 to 10 mm. By satisfying the above-described range in the size of the grinding medium, the core-shell shaped alloy in the metal recovery composition can be easily separated into a core portion and a shell portion in the wet grinding step.

[0066] If the size of the above-mentioned grinding medium exceeds the upper limit of the above-mentioned range, there is a problem that the pores between the balls become larger, thereby weakening the friction between the sample and the ball. If the size of the above-mentioned grinding medium exceeds the lower limit of the above-mentioned range, there is a problem that the grinding performance is reduced because the sample is not easily supplied between the pores between the balls.

[0067] In one embodiment, the method for recovering valuable metals may include a second magnetic separation step of separating a magnetic material from the resultant product of the crushing step. The second magnetic separation step may be a step of recovering a valuable metal alloy including nickel, cobalt, and manganese, specifically the core material described above, and a shell material that is a lithium compound including lithium, from the resultant product of the crushing step. The core material may be a magnetic material that includes the valuable metal, specifically cobalt, and has magnetic properties, and the lithium compound may be an oxide that does not have magnetic properties.

[0068] In one embodiment, the second magnetic separation step may be performed at a magnetic force of 1,000 Gauss or greater. Specifically, the second magnetic separation step may be performed within a range of 1,000 to 5,000 Gauss, and more specifically, within a range of 2,000 to 3,000 Gauss. By performing the second magnetic separation step within the above range, there is an advantage in that valuable metals can be efficiently separated.

[0069] If the second magnetic separation step is performed at a magnetic range that is outside the upper limit of the above range, the recovery rate increases because even trace amounts of valuable metals are recovered, but the grade of the recovered valuable metals is lowered and the amount of impurities such as oxides is increased, which lowers the process efficiency in the subsequent wet refining process and causes an uneconomical problem. If the second magnetic separation step is performed at a magnetic range that is outside the lower limit of the above range, the recovery rate of valuable metals is lowered, which causes an increase in the loss of valuable metals such as nickel, cobalt, and manganese.

[0070] In one embodiment, the second magnetic separation step may include a water spraying step. Specifically, the second magnetic separation step may be performed by spraying water when separating the magnetic and non-magnetic materials in the metal recovery composition. More specifically, the water may be sprayed in the opposite direction of the drum in which the magnetic material is recovered, thereby preventing the entrapment of the non-magnetic material and efficiently collecting the magnetic material.

[0071] In one embodiment, the average particle diameter (D50) of the core material, which is the first metal material that has undergone the crushing step, may be 50 to 1,000 μm. Specifically, the average particle diameter (D50) may refer to the particle diameter when the cumulative percentage of the core material reaches 50%. The average particle diameter (D50) may be 100 to 200 μm, specifically, 130 to 180 μm.

[0072] In one embodiment, the average particle diameter (D50) of the shell material, which is the second metal material that has undergone the crushing step, may be 50 to 500 μm. Specifically, the average particle diameter (D50) may refer to the particle diameter when the cumulative percentage of the shell material reaches 50%. The average particle diameter (D50) may be 50 to 100 μm, specifically, 60 to 90 μm, and more specifically, 64 to 80 μm.

[0073] The average particle diameter (D50) of the core material can satisfy the above-mentioned range by undergoing the above-mentioned wet grinding process. When the average particle diameter (D50) of the core material satisfies the above-mentioned range, it can be confirmed that the recovery rate of valuable metals is high.

[0074] If the average particle diameter (D50) of the core material exceeds the upper limit of the aforementioned range, there is a high possibility that impurities are mixed in the core material, which lowers the quality and recovery rate of the valuable metal. If the average particle diameter (D50) of the core material exceeds the lower limit of the aforementioned range, there is a problem that the content of the valuable metal in the core material is excessively reduced, which lowers the recovery rate of the valuable metal.

[0075] The average particle diameter (D50) of the shell material separated from the core through the above-described grinding step can satisfy the above-described range by going through the above-described wet grinding process. When the average particle diameter (D50) of the shell material satisfies the above-described range, it can be confirmed that the lithium recovery rate is high.

[0076] If the average particle size (D50) of the shell material exceeds the upper limit of the aforementioned range, there is a high possibility that valuable metals are also contained in the shell material, which lowers the quality of the recovered lithium. If the average particle size (D50) of the shell material exceeds the lower limit of the aforementioned range, there is a problem that the lithium content in the shell material is excessively reduced, which lowers the lithium recovery rate.

[0077] In one embodiment, the first metal material that has undergone the pulverization process may contain 0.1 to 5.0 wt% of lithium (Li) and 0.1 to 10 wt% of aluminum (Al), based on 100 wt% of the first metal material. Specifically, the first metal material may contain 0.50 to 0.97 wt% of lithium (Li) and 0.1 to 1.0 wt% of aluminum (Al). More specifically, the first metal material may contain 0.75 to 0.97 wt% of lithium (Li) and 0.1 to 1.0 wt% of aluminum (Al).

[0078] The lithium and aluminum contents of the first metal material can satisfy the aforementioned ranges by undergoing the aforementioned wet grinding process. Specifically, by satisfying the aforementioned ranges for the lithium and aluminum contents of the first metal material, it can be confirmed that the shell portion, which is the second metal material, is easily removed from the first metal material, and that high-grade valuable metals are easily recovered.

[0079] If the contents of the lithium and the aluminum are outside the upper limit of the above-mentioned range, the shell portion arranged on the core portion forming the first metal material may not be easily removed by the above-mentioned crushing process, which may lower the recovery rate of the valuable metal. If the contents of the lithium and the aluminum are outside the lower limit of the above-mentioned range, the above-mentioned crushing process may proceed excessively, which may lower the particle size of the core material, thereby lowering the recovery rate of the valuable metal.

[0080]

[0081] Hereinafter, preferred embodiments and comparative examples of the present invention are described. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

[0082]

[0083] Experimental Example 1

[0084] <Example 1> - Including wet grinding step

[0085] (Preparing the used battery)

[0086] The step of preparing a waste battery involved preparing 2,750 g of NCM622 batteries, and the content ratio of the NCM622 batteries is as shown in Table 1 below.

[0087] Weight(g)Weight(%)Li[%]Ni[%]Co[%]Mn[%]Al[%]Cu[%]C[%]NCM6222750.01006.0432.3510.739.986.0710.7324.50

[0088]

[0089] (Steps for shredding used batteries)

[0090] The above-mentioned waste batteries were shredded into particles ranging from 40 mm to 100 mm using a two-axis, two-stage shredder. The shredded battery shreds had a layered structure in which a cathode, an anode, and a separator were sequentially stacked, and the layered structure was stacked in at least one layer. The size of the battery shreds was 100 mm or less. The size of the battery shreds refers to the length based on the major axis among the width, length, and height of the battery shreds. The shredding was completed within 5 minutes for modules and within 3 minutes for cells.

[0091]

[0092] (Step of dry heat treatment of the battery)

[0093] The above battery was reduced at a high temperature in a high-temperature reduction furnace at 1,350°C, which is the temperature at which lithium oxide of the battery, for example, battery shreds, is reduced, and the process was performed in an atmosphere in which the partial pressure of oxygen (O2) gas was 1.0 vol% and the partial pressure of argon (Ar) gas was 99.0 vol%. The battery shreds were heat-treated at the above-mentioned temperature and gas atmosphere to obtain a valuable metal recovery composition including a black alloy. Here, the black alloy refers to a valuable metal recovery composition having an NCM alloy as a core and LiAl2O attached to a portion of the surface.

[0094] Figure 1 is a SEM photograph of a composition for recovering valuable metals obtained by high-temperature reduction treatment of battery shreds of the present invention.

[0095] Referring to Fig. 1, it was confirmed that the waste battery shreds were subjected to the aforementioned high-temperature reduction treatment, resulting in the formation of LiAl2O bonded to the surface of the NCM alloy. Specifically, it was confirmed that LiAl2O physically or chemically bonds with lithium disposed on the surface of the NCM alloy to form a core-shell structure. This is confirmed because the NCM alloy containing the reduced lithium as the cathode active material has magnetism, and after melting in the form of droplets, LiAl2O oxide is fused to the surface of the solidified magnetic alloy.

[0096]

[0097] (Step of selecting the mouth)

[0098] A composition for recovering valuable metals containing black alloy was sieved through a 1.18 mm sieve to separate reactants exceeding 1.18 mm from reactants less than or equal to 1.18 mm. The reactants exceeding 1.18 mm were separated and directly fed into a leaching process, and only the reactants less than or equal to 1.18 mm were subjected to a primary magnetic separation process.

[0099]

[0100] (1st magnetic selection stage)

[0101] A first magnetic separation step was performed on the reactants obtained through particle size separation with a magnetic force of 1,000 Gauss or higher. At this time, water was sprayed in the opposite direction of the drum from which the magnetic material was recovered to prevent the entrapment of non-magnetic materials during the magnetic separation.

[0102]

[0103] (Wet grinding stage)

[0104] The magnetic material recovered through the first magnetic separation step includes a valuable metal recovery composition having an NCM alloy as a core and LiAl2O attached to a portion of the surface as described above. In order to increase the NCM grade and the Li recovery rate, a wet grinding process was performed to separate the core including the valuable metal and the surface including lithium aluminum oxide. Specifically, the wet grinding process was performed using a vertical stirring grinder (Attriction Mill).

[0105] At this time, in order to increase the efficiency of wet grinding, the pulp density was 30% or more, the rpm of the vertical stirring grinder was 300 to 500 rpm, the grinding time was 30 minutes, and the size of the zirconia ball as the grinding medium was 4 mm, and the wet grinding step was performed.

[0106] Table 2 below shows the change in quality of each component before and after the wet grinding step described above.

[0107] Specifically, Table 2 below shows the grades by component of the magnetic body selected through the first magnetic separation step before the wet grinding step and the grades by component of the resultant product in which the shell portion of the magnetic body is separated after the wet grinding step.

[0108] Ni[wt%]Co[wt%]Mn[wt%]Li[wt%]Al[wt%]Si[wt%]Cu[wt%]Before wet grinding step30.109.469.512.557.270.3018.15After wet grinding step35.6211.3911.070.652.020.2119.26

[0109] Looking at Table 2 and Figure 2 above, it can be confirmed that after the wet grinding step, the lithium aluminum oxide placed in the shell is separated from the NCM alloy, and the grade of the valuable metals of Ni, Co, and Mn is increased.

[0110]

[0111] (Second magnetic selection stage)

[0112] The magnetic material among the reactants, in which the core and shell portions are separated through wet milling, undergoes secondary magnetic separation. At this time, the magnetic force of the drum is adjusted to 1,000 Gauss or higher as a condition for magnetic separation. To prevent the capture of non-magnetic materials, water is sprayed in the opposite direction of the drum from which the magnetic material is recovered, and the final product, the NCM alloy, is recovered.

[0113]

[0114] <Comparative Example 1> - Wet grinding step not included

[0115] The same procedure as Example 1 was followed, except that a separate wet crushing step was not included for the magnetic material recovered through the first magnetic separation step.

[0116]

[0117] <Comparative Example 2> - Dry grinding stage

[0118] The same procedure as Example 1 was followed, except that dry grinding was performed with a pulp density of 0%.

[0119]

[0120] Table 3 below shows the recovery rates of Ni, Co, Mn, Cu, Li compounds, and C in the methods for recovering valuable metals according to Example 1, Comparative Example 1, and Comparative Example 2.

[0121] Ni[%]Co[%]Mn[%]Cu[%]Li[%]Al[%]C[%]Example 195.6795.8394.7586.9238.4838.5034.92Comparative Example 190.4489.6688.5482.5566.4168.2152.23Comparative Example 292.5592.1190.8784.6151.8760.1549.51

[0122] Looking at Table 3 above, in the case of Example 1, which went through a wet grinding step, it can be confirmed that the recovery rates of valuable metals such as nickel, cobalt, and manganese are all high at over 94%, and the recovery rate of lithium is also high compared to Comparative Example 1. In contrast, in the case of Comparative Example 1, since a separate wet grinding step was not performed, it can be confirmed that the recovery rates of lithium and valuable metals such as nickel, cobalt, and manganese are low. This is because it was confirmed that lithium was recovered in a state where it was arranged on the surface of the valuable metal alloy including nickel, cobalt, and manganese since Comparative Example 1 did not go through a wet grinding step.

[0123]

[0124] <Experimental Example 3> - Control of wet grinding conditions

[0125] <Example 2> - 40% of light solution, 500 rpm, 35 minutes of grinding time

[0126] The same procedure as Example 1 was followed, except that in the wet grinding step, the pulp density was 40%, the rpm of the vertical stirring grinder was 500 rpm, the grinding time was 35 minutes, and the size of the zirconia ball as the grinding medium was 5 mm.

[0127]

[0128] <Example 3> - 50% of the light solution, 300 rpm, 10 minutes of grinding time

[0129] The same procedure as Example 1 was followed, except that in the wet grinding step, the pulp density was 50%, the rpm of the vertical stirring grinder was 300 rpm, the grinding time was 10 minutes, and the size of the zirconia ball as the grinding medium was 5 mm.

[0130]

[0131] <Example 4> - 30% of light solution, 500 rpm, 10 minutes of grinding time

[0132] The same procedure as Example 1 was followed, except that in the wet grinding step, the pulp density was 30%, the rpm of the vertical stirring grinder was 500 rpm, the grinding time was 10 minutes, and the size of the zirconia ball as the grinding medium was 5 mm.

[0133]

[0134] <Example 5> - 50% of the light solution, 700 rpm, 60 minutes of grinding time

[0135] The same procedure as Example 1 was followed, except that in the wet grinding step, the pulp density was 50%, the rpm of the vertical stirring grinder was 700 rpm, the grinding time was 60 minutes, and the size of the zirconia ball as the grinding medium was 5 mm.

[0136]

[0137] <Comparative Example 3> - Below the lower limit of the light liquid

[0138] The same procedure as Example 1 was followed, except that in the wet grinding step, the pulp density was 20%, the rpm of the vertical stirring grinder was 300 rpm, the grinding time was 60 minutes, and the size of the zirconia ball as the grinding medium was 5 mm.

[0139]

[0140] <Comparative Example 4> - Exceeding the upper limit of the light liquid

[0141] The same procedure as Example 1 was followed, except that in the wet grinding step, the pulp density was 60%, the rpm of the vertical stirring grinder was 300 rpm, the grinding time was 60 minutes, and the size of the zirconia ball as the grinding medium was 5 mm.

[0142]

[0143] <Comparative Example 5> - Below the lower limit of rpm

[0144] The same procedure as Example 1 was followed, except that in the wet grinding step, the pulp density was 30%, the rpm of the vertical stirring grinder was 100 rpm, the grinding time was 30 minutes, and the size of the zirconia ball as the grinding medium was 5 mm.

[0145]

[0146] <Comparative Example 6> - Exceeding the upper limit of rpm

[0147] The same procedure as Example 1 was followed, except that in the wet grinding step, the pulp density was 30%, the rpm of the vertical stirring grinder was 700 rpm, the grinding time was 30 minutes, and the size of the zirconia ball as the grinding medium was 5 mm.

[0148]

[0149] <Comparative Example 7> - Below the lower limit of the crushing time

[0150] The same procedure as Example 1 was followed, except that in the wet grinding step, the pulp density was 30%, the rpm of the vertical stirring grinder was 300 rpm, the grinding time was 5 minutes, and the size of the zirconia ball as the grinding medium was 5 mm.

[0151]

[0152] <Comparative Example 8> - Exceeding the upper limit of crushing time

[0153] The same procedure as Example 1 was followed, except that in the wet grinding step, the pulp density was 30%, the rpm of the vertical stirring grinder was 300 rpm, the grinding time was 90 minutes, and the size of the zirconia ball as the grinding medium was 5 mm.

[0154]

[0155] <Comparative Example 9> - Zirconia ball size exceeds the lower limit

[0156] The same procedure as Example 1 was followed, except that in the wet grinding step, the pulp density was 30%, the rpm of the vertical stirring grinder was 300 rpm, the grinding time was 60 minutes, and the size of the zirconia ball as the grinding medium was 3 mm.

[0157]

[0158] Table 4 below shows the recovery rates of Ni, Co, Mn, Cu, Li compounds, and C in the methods for recovering valuable metals according to Examples 2 to 5 and Comparative Examples 3 to 10.

[0159] Ni[%]Co[%]Mn[%]Cu[%]Li[%]Al[%]C[%]RemarksExample 296.1596.2595.0793.4023.4224.1433.10Example 398.2498.3397.3897.7041.6538.7354.67Example 497.2997.4496.7498.4943.3440.0660.23Example 598.4398.4998.2397.5968.3366.1852.23Comparative Example 393.7794.1093.8891.2233.1433.8632.16Less than the lower limit of the ore solutionComparative Example 492.6492.8993.1492.6430.8836.8740.14Comparison example of exceeding the upper limit of the light liquid 592.5793.0892.8890.8733.7434.1045.12RPM Comparison example of below the lower limit 693.9494.0193.5894.0730.4431.0136.14RPM Comparison example of exceeding the upper limit 791.4491.5992.1492.1450.8451.2160.44Comparison example of below the lower limit of the grinding time 893.5793.8994.0193.4033.5434.2736.57Comparison example of exceeding the upper limit of the grinding time 994.5195.0295.1195.1742.5844.0150.23 Zirconia ball size lower limit value Comparison example 1092.7993.2492.1890.5736.7434.4150.12 Zirconia ball size upper limit value

[0160] Looking at Table 4 above, it can be seen that Examples 2 to 5, in which the wet grinding conditions satisfy the scope of the present invention in the wet grinding step, have excellent recovery rates of nickel, cobalt, and manganese. In contrast, it can be seen that Comparative Examples 3 to 10, in which the wet grinding conditions do not satisfy the scope of the present invention, have lower recovery rates of nickel, cobalt, manganese, and lithium compared to Examples 2 to 5.

[0161]

[0162] <Experimental Example 4> - Characteristics of the final product

[0163] Table 5 below shows the characteristics of the final product when the method for recovering valuable metals was performed according to the examples and comparative examples of the present invention. The average particle size of the NCM alloy and lithium compound in Table 5 below was measured by the following method. Specifically, it refers to the component analysis value before and after the NCM alloy is crushed, and the lithium and aluminum contents in the NCM alloy refer to the contents in the NCM alloy before and after the crushing step.

[0164] NCM alloy average particle size, lithium compound average particle size (D50) [㎛]: The average particle size of NCM alloy and lithium compounds was measured using a particle size analysis device, Mastersizer 3000.

[0165] NCM alloy average particle size (D50) [㎛] Lithium compound average particle size (D50) [㎛] Li content in NCM alloy [wt%] Al content in NCM alloy [wt%] Remarks Example 2 140640.970.94 Example 3 151750.750.79 Example 4 170800.710.76 Example 5 135710.770.80 Comparative Example 3 150911.041.11 Less than the lower limit of ore Comparative Example 4 153870.991.04 More than the upper limit of ore Comparative Example 5 170841.171.21 Less than the lower limit of RPM Comparative Example 6 144660.981.08 More than the upper limit of RPM Comparative Example 7 166911.230.30 Lower limit of crushing time Value less than comparison example 8204661.091.09 Crushing time upper limit value exceeding comparison example 9224411.081.11 Zirconia ball size lower limit value comparison example 102161151.141.11 Zirconia ball size upper limit value

[0166] Looking at Table 5 above, it can be confirmed that the average particle size of the NCM alloy, the average particle size of the lithium compound, the Li content in the NCM alloy, and the Al content of the comparative examples that do not satisfy the manufacturing conditions of the present invention are not included in the scope of the present invention compared to the examples that satisfy the manufacturing conditions of the present invention. Specifically, it can be confirmed that the average particle size of the lithium compound, the Li content in the NCM alloy, and the Al content are not included in the scope of the present invention when the content of the ore is outside the conditions of the present invention. If the RPM and the grinding time are excessively high, there is a problem that the particle size of the NCM alloy becomes excessively small. If the RPM and the grinding time are excessively low, there is a problem that the average particle size of the lithium compound becomes excessively large. In addition, if the zirconia ball size is excessively large, there is a problem that the grinding ability is weak because the balls do not provide frictional force to the particles, etc., and if the zirconia ball size is excessively small, there is a problem that agglomeration occurs due to the ductility of the metal NCM particles caused by over-grinding.

[0167] The present invention is not limited to the above-described embodiments, but can be manufactured in a variety of different forms. Those skilled in the art will appreciate that the present invention can be implemented in other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

1. A step of obtaining a composition for recovering valuable metals by dry heat treatment of a spent battery; and A crushing step for separating a first metal material including a valuable metal from the above metal recovery composition and a second metal material disposed on at least a portion of the surface of the metal material and including lithium, A method for recovering valuable metals, wherein the above crushing step is performed under wet conditions.

2. In paragraph 1, A method for recovering valuable metals having a pulp density of 30 to 55% under the above wet conditions.

3. In paragraph 1, The above crushing step is performed by a vertical stirring crusher (Attrition Mill), A method for recovering valuable metals, wherein the rpm of the vertical stirring crusher under the above wet conditions is 250 to 1,000 rpm.

4. In paragraph 1, A method for recovering valuable metals, wherein the grinding time under the above wet conditions is 10 to 60 minutes.

5. In paragraph 1, The above crushing step is performed by a vertical stirring crusher (Attrition Mill), A method for recovering valuable metals, wherein the size of the grinding medium of the above grinder is 4 mm or more.

6. In paragraph 1, Between the step of obtaining the above metal recovery composition and the step of crushing, A method for recovering valuable metals, comprising a step of particle size separation into coarse particles and fine particles for the above-mentioned valuable metal recovery composition.

7. In paragraph 6, A method for recovering valuable metals, comprising a first magnetic separation step for separating magnetic substances from fine particles separated through the above particle size separation step.

8. In paragraph 7, A method for recovering valuable metals, comprising a second magnetic separation step for separating magnetic substances from the results obtained through the above crushing step.

9. In paragraph 8, A method for recovering valuable metals, wherein the first magnetic separation step and the second magnetic separation step are performed at a magnetic force of 1,000 Gauss or more.

10. In paragraph 8, A method for recovering valuable metals, wherein the first magnetic separation step and the second magnetic separation step include a water injection step.

11. In paragraph 10, A method for recovering valuable metals, wherein the water injection step performs water injection in the opposite direction of the drum from which the magnetic material is recovered in the first magnetic separation step and the second magnetic separation step.

12. In paragraph 1, A method for recovering valuable metals, wherein in the step of obtaining the above-mentioned valuable metal recovery composition, the heat treatment temperature is performed at 1,100°C or higher.

13. In paragraph 11, The composition for recovering valuable metals obtained by dry heat treatment of the material obtained from the waste battery is as follows: A core portion of a first metal material comprising at least one of nickel, cobalt, and manganese; and A method for recovering valuable metals, comprising a shell portion disposed on at least a portion of the surface of the core portion and combined with lithium disposed on the surface of the core portion.

14. A step of obtaining a composition for recovering valuable metals by dry heat treatment of a material obtained from a spent battery; and A crushing step for separating a first metal material including a valuable metal from the above metal recovery composition and a second metal material disposed on at least a portion of the surface of the metal material and including lithium, After going through the above grinding step, The above first metal material is based on 100 wt% of the above first metal material, Lithium (Li) is contained in an amount of 0.50 to 1.00 wt%, Method for recovering valuable metals.

15. In paragraph 14, The above first metal material is based on 100 wt% of the above first metal material, A method for recovering a valuable metal containing 0.1 to 10 wt% of aluminum (Al).

16. In paragraph 14, A method for recovering valuable metals, wherein the average particle diameter (D50) of the first metal material is 50 to 1,000 ㎛.

17. In paragraph 14, A method for recovering precious metals, wherein the average particle diameter (D50) of the second metal material is 50 to 500 ㎛.

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