Valuable metal reactant, valuable metal crushed material, and valuable metal recovery method

Abstract

Regarding valuable metal reactants, valuable metal crushed material, and valuable metal recovery methods, the valuable metal reactant of the present invention is a valuable metal reactant containing valuable metals recovered from waste batteries, and includes a first valuable metal-containing material containing a magnetic substance, a second valuable metal-containing material containing a non-magnetic substance, a carbon compound containing carbon, and other remaining impurities, and the first valuable metal-containing material includes a third valuable metal-containing material and a first lithium compound attached to the surface of the third valuable metal-containing material, and the lithium content of the first lithium compound is 1.5% or more by weight of lithium in the first valuable metal-containing material.

Description

[Technical Field]

[0001] The present invention relates to waste batteries, valuable metal reactants recovered from recycled waste batteries, valuable metal crushed materials, and a valuable metal recovery method. [Background technology]

[0002] As demand for electric vehicles increases worldwide, the disposal of waste batteries generated from these vehicles is becoming a social issue. Lithium secondary batteries, which are the main raw materials for waste batteries, contain organic solvents, explosive substances, and heavy metals such as Ni, Co, Mn, and Fe. Ni, Co, Mn, and Li are highly rare and valuable metals, and therefore, the recovery and recycling processes of discarded lithium secondary batteries have emerged as an important research field.

[0003] Specifically, a lithium secondary battery mainly comprises copper and aluminum used as a current collector, an oxide containing Li, Ni, Co, and Mn that constitutes the cathode material, and graphite used as the anode material, as well as a separator that separates the cathode material from the anode material and an electrolyte that is poured into the separator.The solvent and salt that constitute the electrolyte are typically a mixture of carbonate organic compounds such as ethylene carbonate and propylene carbonate, e.g., LiPF6.

[0004] In order to utilize the waste batteries, there has been growing interest in a waste battery recycling process in which the waste batteries are crushed to generate intermediate materials such as waste battery crushed material or black powder, and valuable metals are recovered through post-processing.

[0005] Specifically, waste batteries are primarily composed of expensive, valuable metal elements such as Ni, Co, Mn, and Li. These batteries are, for example, secondary batteries that have reached the end of their service life after being used for 5 to 10 years. Recycling the primary components of these batteries is essential for environmental and cost reasons. The waste batteries undergo conventional crushing, pulverization, or gravity separation processes to produce intermediate products, such as black powder-like cathode and anode mixtures. The valuable metals essential for battery production are recovered from the resulting black powder through wet processes such as leaching, solvent extraction, or crystallization. This facilitates the supply and demand of raw materials and significantly reduces battery manufacturing costs.

[0006] As a method for recovering used batteries, a method has been studied in which graphite is first separated in the sorting process of the calcined heat-treated reactant, followed by magnetic separation to recover valuable metals. However, when the graphite is first separated, the graphite is mixed with a large amount of fine lithium compounds such as LiAlO2, Li2CO3, LiF, or Li5AlO4, and in the post-processing sorting process to remove the graphite, the lithium compounds are mixed in, resulting in a loss of lithium content that is transferred to the subsequent process, resulting in a decrease in the lithium recovery rate. Summary of the Invention [Problem to be solved by the invention]

[0007] The valuable metal reactant according to one embodiment of the present invention provides a reactant with a high recovery rate of valuable metals, specifically lithium, when valuable metals are recovered in a subsequent step.

[0008] According to another embodiment of the present invention, valuable metal crushed material is produced by crushing valuable metal reactants having the above-described advantages, and provides crushed material with a high recovery rate of valuable metals.

[0009] The valuable metal recovery method according to another embodiment of the present invention has the above-mentioned advantages and provides a valuable metal recovery method with an excellent valuable metal recovery rate. [Means for solving the problem]

[0010] A valuable metal reactant according to one embodiment of the present invention is a valuable metal reactant containing valuable metals recovered from waste batteries, and includes a first valuable metal-containing material containing a magnetic material, a second valuable metal-containing material containing a non-magnetic material, a carbon compound containing carbon, and other remaining impurities, and the first valuable metal-containing material includes a third valuable metal-containing material and a first lithium compound attached to the surface of the third valuable metal-containing material, and the lithium content of the first lithium compound can include 1.5% or more by weight of lithium in the first valuable metal-containing material. In one embodiment, the first lithium compound can include LiAlO2; and a lithium compound including at least one of Li2CO3, LiF, and Li5AlO4.

[0011] In one embodiment, the second valuable metal-containing material includes a second lithium compound, and the lithium content of the second lithium compound may be less than 20 wt% lithium in the second valuable metal-containing material. In one embodiment, the second lithium compound may include at least one of LiAlO2; and Li2CO3, LiF, and Li5AlO4.

[0012] In one embodiment, the third valuable metal-containing material may include at least one of cobalt, nickel, and manganese. In one embodiment, the second valuable metal-containing material may include at least one of a second lithium compound, aluminum, aluminum oxide, copper, copper oxide, manganese, and manganese oxide.

[0013] According to another embodiment of the present invention, valuable metal crushed material may be produced by crushing the valuable metal reactant. In one embodiment, the valuable metal crushed material may have an average particle size of 100 to 4000 μm.

[0014] Another embodiment of the valuable metal recovery method of the present invention includes a high-temperature reduction step of subjecting crushed battery material to a high-temperature reduction reaction to obtain a valuable metal reactant; a magnetic separation step of separating the valuable metal reactant into a first valuable metal-containing material containing a magnetic material and a second valuable metal-containing material containing a non-magnetic material; and a first separation step of separating the second valuable metal-containing material into a carbon-containing material containing carbon and a second lithium compound, wherein the first valuable metal-containing material includes a third valuable metal-containing material and a first lithium compound attached to the surface of the third valuable metal-containing material, and the lithium content of the first lithium compound is 1.5% or more by weight of lithium in the first valuable metal-containing material.

[0015] In one embodiment, a second separation step may be included in which the first valuable metal-containing material is separated into a third valuable metal-containing material and the first lithium compound.

[0016] In one embodiment, the step of crushing the first valuable metal-containing material to separate it into a third valuable metal-containing material and the first lithium compound may include a step of desorbing the first lithium compound attached to the surface of the first valuable metal-containing material.

[0017] In one embodiment, the second separation step may include crushing the first valuable metal-containing material to an average particle size of 100 to 4000 μm. In one embodiment, the lithium content of the second lithium compound may be less than 20 wt % lithium in the second valuable metal-containing material.

[0018] In one embodiment, the second valuable metal-containing material may include at least one of aluminum, aluminum oxide, copper, copper oxide, manganese, and manganese oxide. In one embodiment, the third valuable metal-containing material may include an alloy or oxide containing at least one of cobalt, nickel, and manganese.

[0019] In one embodiment, the first separation step can be performed by particle size separation. In one embodiment, after the high-temperature reduction step and before the magnetic separation step, the step of removing impurities can further include removing impurities by particle size separation in the range of 5 to 10 mm. In one embodiment, before the high-temperature reduction step, the method can further include freezing the batteries that will be the base material for the crushed battery material.

[0020] In one embodiment, the step of freezing the battery may satisfy the following formula 1: <Expression 1> Minimum cooling time (Hr)=A×(W 0.33 ) (A=4×e (-0.02×dT) , W = battery weight (kg), dT = |external cooling temperature - target temperature|, || means absolute value) [Effects of the Invention]

[0021] The valuable metal reactant according to one embodiment of the present invention provides a reactant with a high recovery rate of valuable metals, specifically lithium, when valuable metals are recovered in a subsequent step.

[0022] According to another embodiment of the present invention, valuable metal crushed material is produced by crushing valuable metal reactants having the above-described advantages, and provides crushed material with a high recovery rate of valuable metals.

[0023] Another embodiment of the present invention provides a valuable metal recovery method that has the above-mentioned advantages. [Brief explanation of the drawings]

[0024] [Figure 1] 10 is a graph showing minimum cooling time according to one embodiment of the present invention. [Figure 2] 1 is a graph showing the relationship between battery weight, external cooling temperature, and cooling time according to an embodiment of the present invention. [Figure 3a] This is a photograph of a comparative example in which a fire broke out when the product was crushed after being frozen for less than the minimum cooling time. [Figure 3b] This is a photograph of a comparative example in which a fire broke out when the product was crushed after being frozen for less than the minimum cooling time. [Figure 3c] This is a photograph of an example in which no fire occurred when the product was crushed after being frozen for a period longer than the minimum cooling time required in the example. [Figure 3d] This is a photograph of an example in which no fire occurred when the product was crushed after being frozen for a period longer than the minimum cooling time required in the example. DETAILED DESCRIPTION OF THE INVENTION

[0025] Terms such as "first," "second," and "third" are used to describe various parts, components, regions, layers, and / or sections, but are not limited thereto. These terms are used only to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Thus, a first part, component, region, layer, or section described below can be referred to as a second part, component, region, layer, or section without departing from the scope of the present invention.

[0026] The terminology used herein is merely for the purpose of referring to particular embodiments and is not intended to limit the present invention. As used herein, the singular forms "a," "an," and "the" include the plural forms unless the context clearly dictates otherwise. As used herein, the term "comprises" refers to the inclusion of specific properties, regions, integers, steps, operations, elements, and / or components, and does not exclude the presence or addition of other properties, regions, integers, steps, operations, elements, and / or components.

[0027] When an element is described as being "on" or "above" another element, it may be on or above the other element, or may have other elements between them. In contrast, when an element is referred to as being "directly on" another element, there are no other elements between them.

[0028] Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention pertains. Terms defined in commonly used dictionaries are additionally interpreted to have a meaning consistent with the relevant technical literature and the presently disclosed content, and are not interpreted in an ideal or very formal sense unless defined.

[0029] DETAILED DESCRIPTION OF THE INVENTION The following detailed description of the present invention is provided by way of example only and is not intended to limit the scope of the present invention, which is defined solely by the scope of the claims set forth below.

[0030] According to one embodiment of the present invention, the valuable metal reactant is a valuable metal reactant containing valuable metals recovered from waste batteries, and may include a first valuable metal-containing material containing a magnetic material, a second valuable metal-containing material containing a non-magnetic material, a carbon compound containing carbon, and other remaining impurities. The valuable metal reactant refers to a reactant obtained after subjecting crushed battery material to a high-temperature reduction reaction, followed by magnetic separation, and then extracting the carbon compound, e.g., graphite, from the second valuable metal-containing material in the valuable metal recovery method described below.

[0031] In one embodiment, the first valuable metal-containing material may include a third valuable metal-containing material and a first lithium compound attached to the surface of the third valuable metal-containing material. The valuable metal reactant is a reactant generated in a step before crushing the first valuable metal-containing material in the valuable metal recovery method described below, and may include the third valuable metal-containing material alone, or the third valuable metal-containing material with the first lithium compound attached to its surface.

[0032] In one embodiment, the third valuable metal-containing material in the first valuable metal-containing material may include at least one of cobalt, nickel, and manganese. In one embodiment, the second valuable metal-containing material may include at least one of a second lithium compound, aluminum, aluminum oxide, copper, copper oxide, manganese, and manganese oxide.

[0033] In one embodiment, the first lithium compound is LiAlO2; and Li2C O3 The first lithium compound may be a composition containing at least one of LiF, LiAlO, and LiAlO. In one embodiment, the lithium content of the first lithium compound may be 1.5% or more by weight in the first valuable metal-containing material. Specifically, the lithium content of the first lithium compound may be 1.8% to 9.0%, more specifically, 6.21 to 7.39% by weight in the first valuable metal-containing material.

[0034] When the lithium content of the first lithium compound is within the above-mentioned range in the first valuable metal-containing material, it is less susceptible to leaching by graphite in a subsequent process, and the lithium recovery rate can be increased. When the lithium content of the first lithium compound is not within the above-mentioned range in the first valuable metal-containing material, it is significantly susceptible to leaching by graphite, and there is a problem that the lithium recovery rate decreases.

[0035] In one embodiment, the lithium content of the second lithium compound may be less than 20% by weight of lithium in the second valuable metal-containing material. Specifically, the lithium content of the second lithium compound may be 9.0% or less, 6.0% or less, or more specifically, 1.45% or less by weight of lithium in the second valuable metal-containing material. The lithium content of the second lithium compound may be greater than 0% in the second valuable metal-containing material. This is because lithium contamination is unavoidable when the valuable metal-containing material undergoes a classification process after magnetic separation.

[0036] When the lithium content of the second lithium compound in the second valuable metal-containing material satisfies the above-mentioned range, there is an advantage in that the amount of lithium compound lost together with graphite during classification can be reduced. When the lithium content of the second lithium compound in the second valuable metal-containing material exceeds the above-mentioned range, there is a problem in that the lithium is significantly affected by leaching by graphite in a subsequent process, resulting in a reduced lithium recovery rate.

[0037] According to another embodiment of the present invention, valuable metal crushed material may be produced by crushing the above-described valuable metal reactant. Specifically, the valuable metal crushed material may be produced through a crushing step performed to separate third valuable metal-containing material having the first lithium compound disposed on the surface of the first valuable metal-containing material of the above-described valuable metal reactant.

[0038] More specifically, the valuable metal crushed material may include a crushed third valuable metal-containing material and a first lithium compound. In one embodiment, the valuable metal crushed material may have an average particle size of 100 to 4000 μm.

[0039] A valuable metal recovery method according to another embodiment of the present invention includes a step of subjecting crushed battery material to a high-temperature reduction reaction, a magnetic separation step of separating the reaction product produced after the high-temperature reduction reaction into a first valuable metal-containing material containing a magnetic substance and a second valuable metal-containing material containing a non-magnetic substance, and a first separation step of separating a carbon-containing material containing carbon from the valuable metal-containing material from the product obtained after the magnetic separation step.

[0040] The term "crushed battery material" refers to a material that will become a base material for crushed battery material or the material itself after crushing. The base material for crushed battery material can include batteries that have reached the end of their life, waste batteries, and waste generated during the manufacturing process of lithium-ion batteries. Specifically, the waste batteries can include cathode materials such as scrap, jelly rolls, and slurry that constitute waste batteries, defective products generated during the manufacturing process, residues within the manufacturing process, and debris generated during the manufacturing process. The base material for crushed battery material can then be manufactured into crushed battery material through a crushing process.

[0041] The crushed material itself may be a crushed product itself, such as black powder. In this way, by recycling waste batteries, crushed battery material is produced, which is environmentally friendly and economically advantageous.

[0042] The step of subjecting the crushed battery materials to a high-temperature reduction reaction is a step of subjecting the crushed battery materials to a high temperature by placing the crushed battery materials in a heating furnace capable of raising the temperature to a temperature equal to or higher than the melting point of the crushed battery materials. The step of subjecting the crushed battery materials to a high-temperature reduction reaction may include heat treatment conditions for performing a high-temperature reduction reaction without a melting step.

[0043] In one embodiment, the step of subjecting the crushed battery material to a high-temperature reduction reaction can be performed at a temperature in the range of 1,150 to 1,350° C. In one embodiment, the step of subjecting the crushed battery material to a high-temperature reduction reaction can be performed under conditions of 5 vol% or less of oxygen. Performing the high-temperature reduction reaction under these conditions has the advantages of improving the lithium recovery rate and reducing CO2 emissions.

[0044] The magnetic separation step, which separates the reaction product generated after the high-temperature reduction reaction into a first valuable metal-containing material containing a magnetic substance and a second valuable metal-containing material containing a non-magnetic substance, is a step of separating the first valuable metal-containing material containing a magnetic substance and a second valuable metal-containing material containing a non-magnetic substance by magnetic separation. The magnetic separation can separate particles by contact with the magnetic substance, for example, and various types of magnetic separation methods can be applied.

[0045] When performing the magnetic separation, a first valuable metal-containing material containing a magnetic substance such as cobalt can be selected and separated, and materials other than the first valuable metal-containing material that do not contain magnetic substances can be separated as a second valuable metal-containing material.

[0046] The first valuable metal-containing material may include a third valuable metal-containing material and a first lithium compound attached to the surface of the third valuable metal-containing material. Specifically, the first valuable metal-containing material may be cobalt, nickel, manganese, or an oxide thereof; an alloy containing at least two of cobalt, nickel, and manganese, or an oxide thereof.

[0047] In one embodiment, at least a portion of the first valuable metal-containing material may be contained in the third valuable metal-containing material and a first lithium compound disposed on the surface of the third valuable metal-containing material. Specifically, the first valuable metal-containing material may be composed of the third valuable metal-containing material alone, or the first valuable metal-containing material and the first valuable metal-containing material having the first lithium compound disposed on its surface. In this way, magnetic separation first separates the first valuable metal-containing material having the first lithium compound disposed on its surface, thereby preventing the lithium compound from being detached from the first valuable metal-containing material in the subsequent particle size separation, thereby advantageously increasing the lithium recovery rate.

[0048] The second valuable metal-containing material may include at least one of aluminum, aluminum oxide, copper, copper oxide, manganese, and manganese oxide. The second valuable metal-containing material is a valuable metal-containing material containing a non-magnetic substance, and may include materials such as LiAlO2, Cu, and MnO. In one embodiment, the third valuable metal-containing material may include an alloy or oxide containing at least one of cobalt, nickel, and manganese. In one embodiment, the first lithium compound may be, for example, lithium aluminum oxide, LiAlO2.

[0049] The first separation step of separating the carbon-containing material and the second lithium compound from the second valuable metal-containing material obtained after the magnetic separation step includes separating the carbon-containing material, specifically graphite, from the second valuable metal-containing material including non-magnetic materials obtained after the magnetic separation step. In one embodiment, the graphite separation step can be performed by either particle size separation or gravity separation.

[0050] In one embodiment, the particle size separation or gravity separation can be performed using a means such as a cyclone or a floater. Specifically, the graphite can be separated based on a particle size of 100 μm. The graphite can be separated by particle size separation in the 100 μm or smaller range.

[0051] As described above, by separately separating the graphite from the second valuable metal-containing material obtained after the magnetic separation step through a classification process, the problem of lithium loss due to the inclusion of fine lithium compounds during the graphite removal and sorting process can be resolved compared to the case where the graphite separation process is performed first, and the amount of lithium input in the subsequent process can be increased.

[0052] As described above, in the reaction product obtained by separating and classifying the graphite after magnetic separation, the lithium content of the first lithium compound may be 1.5% or more by weight of the first valuable metal-containing material. Specifically, the lithium content of the first lithium compound may be 6% or more by weight of the first valuable metal-containing material.

[0053] As described above, by performing the magnetic separation step before the classification step, the third valuable metal-containing material, in which the first lithium compound in the first valuable metal-containing material is disposed on the surface, is simultaneously recovered, which has the advantage of being less susceptible to leaching by graphite in the subsequent process and increasing the lithium recovery rate.

[0054] In one embodiment, the lithium content of the second lithium compound may be less than 20% by weight of lithium in the second valuable metal-containing material. Specifically, the lithium content of the second lithium compound may be 17% by weight or less, more specifically 9% by weight or less, more specifically 6.0% by weight or less, more specifically 5.0% by weight or less, and more specifically 1.45% by weight or less of lithium in the second valuable metal-containing material.

[0055] As described above, by separately separating the graphite from the second valuable metal-containing material obtained after the magnetic separation step through a classification process, the problem of lithium loss due to the inclusion of fine lithium compounds during the graphite removal and sorting process can be resolved compared to the case where the graphite separation process is performed first, and the amount of lithium added in the subsequent process can be increased.

[0056] In addition, the second lithium compound may contain a large amount of lithium compounds during the additional screening process for removing the graphite, thereby preventing a problem of a decrease in the Li recovery rate of the second lithium compound in a subsequent process.

[0057] In one embodiment, after the step of separating the carbon-containing material and the second lithium compound from the valuable metal-containing material from the product obtained after the magnetic separation step, a second separation step can be included in which the first valuable metal-containing material is separated from the third valuable metal-containing material and the first lithium compound.

[0058] The second separation step is a step of separating the third valuable metal-containing material and the first lithium compound from the first valuable metal-containing material by mechanical or physical external force, and can separate, for example, an alloy or oxide containing at least one of nickel, cobalt, and manganese and a lithium compound, such as LiAlO2, arranged on the surface of the valuable metal-containing material, from the valuable metal-containing material.

[0059] The second separation step can separate the third valuable metal-containing material from the first lithium compound by applying an external force, such as crushing, to the first valuable metal-containing material to separate the third valuable metal-containing material and the first lithium compound. The second separation step is not limited to the crushing method described above, and various methods can be used as long as they can separate the third valuable metal-containing material from the first lithium compound using an external force. In this way, separating the lithium compound using a physical external force has the advantage of increasing the recovery rate of not only valuable metals such as nickel, cobalt, and manganese, but also lithium.

[0060] In one embodiment, the second separation step of crushing the first valuable metal-containing material to separate it into a third valuable metal-containing material and a first lithium compound can include crushing the first valuable metal-containing material to an average particle size in the range of 100 to 4000 μm. Specifically, the crushing step can include crushing the first valuable metal-containing material to an average particle size in the range of 100 to 1000 μm. By crushing the first valuable metal-containing material to the above range, there is an advantage that the lithium content of the first valuable metal-containing material attached to the surface of the third valuable metal-containing material including NCM is high.

[0061] In the second separation step, if crushing is performed beyond the upper limit of the range, the size of the Ni-Co-Mn-containing alloy produced during high-temperature heat treatment of the crushed material increases, resulting in a problem of increased leaching time in the subsequent wet process.In the second separation step, if crushing is performed beyond the lower limit of the range, the size of the alloy produced during high-temperature heat treatment of crushed material of 100 μm or less decreases, graphite is separated together during magnetic separation, and graphite that is insoluble in acid during the leaching process interferes, resulting in a delay in the process.

[0062] In one embodiment, the second separation step of crushing the first valuable metal-containing material to separate it into a third valuable metal-containing material and a first lithium compound can be performed after the magnetic separation step of separating the reactant produced after the high-temperature reduction reaction into a first valuable metal-containing material containing a magnetic material and a second valuable metal-containing material containing a non-magnetic material. The second separation step can be performed, for example, between the magnetic separation step and the graphite separation step, or after the magnetic separation step and the graphite separation step. Performing the second separation step after the magnetic separation step has the advantage of preventing clumps such as flakes from aggregating.

[0063] In one embodiment, the method may further include a step of removing impurities, such as iron chips and flakes, prior to a magnetic separation step of separating the reactants after the high-temperature reduction reaction into a first valuable metal-containing material containing magnetic material and a second valuable metal-containing material containing non-magnetic material.

[0064] In one embodiment, the impurity removal step can be performed by magnetic separation, particle size separation, or gravity separation. Magnetic separation can be performed using a magnetic material with a magnetic field strength sufficient to separate the iron pieces from valuable metal-containing materials such as NCM alloys. The particle size separation can separate the iron pieces by controlling their particle size. Specifically, the particle size is the average particle size, and particle size separation can be performed based on a standard range of, for example, 5 to 10 mm or more.

[0065] By removing impurities before the above-mentioned magnetic separation, there is an advantage that impurities that may affect the magnetic separation can be removed and the recovery rate of valuable metals can be increased.

[0066] In one embodiment, the crushed battery materials may be subjected to a step of freezing the batteries and a step of crushing the frozen batteries prior to the step of subjecting the crushed battery materials to a high-temperature reduction reaction. By freezing the crushed battery materials prior to crushing, it is possible to prevent the batteries from catching fire during the crushing process.

[0067] The step of freezing the battery is carried out at a temperature sufficient to freeze the electrolyte contained in the battery. Specifically, the freezing step can be carried out, for example, at a temperature range of -150 to -20°C. More specifically, the temperature range is -150 to -50°C, and even more specifically, at a temperature range of -80 to -60°C.

[0068] When the battery is frozen within the above temperature range, the minute voltage remaining inside the battery, for example, about 2 V to 3 V, drops to nearly 0 V. As a result, even if a short circuit occurs due to direct contact between the positive and negative electrodes, no battery reaction occurs, so the battery temperature does not rise and gas generation and combustion of the electrolyte do not occur. Furthermore, because the electrolyte is in a frozen state or a state in which vaporization is suppressed, the mobility of lithium ions is very low, which significantly reduces the electrical conductivity due to the lithium ion migration, and vaporization of the electrolyte does not occur, so flammable gases such as ethylene, propylene, and hydrogen are not generated.

[0069] If the freezing process is performed at a temperature outside the above range, for example, at a temperature higher than -60°C, the remaining voltage 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, which is not appropriate. Furthermore, if the battery is cooled to -150°C, the electrolyte will be sufficiently frozen and the internal voltage of the battery will also drop to 0V, so there is no need to lower the temperature below this. Thus, by including a step of freezing batteries, such as lithium secondary batteries, before crushing them, the battery treatment method advantageously prevents the risk of fire that may occur during the battery crushing process.

[0070] The step of crushing the frozen battery may refer to a step of applying impact or pressure to the battery so that a portion of the battery is detached from the battery. In one embodiment, the step of crushing the battery may refer to a step of crushing the battery, a step of cutting the battery, a step of compressing the battery, or a combination thereof. Specifically, the step of crushing may include any step of breaking the battery to obtain small pieces.

[0071] In one embodiment, the step of crushing the battery may include all of the steps of crushing the frozen battery by compressing the battery or applying an external force such as a shear force or a tensile force to the battery. The step of crushing the battery may be performed using, for example, a crusher.

[0072] In one embodiment, the step of crushing the battery can be performed at least once or more times. Specifically, the step of crushing the battery can be performed at least once or more times continuously or discontinuously.

[0073] In one embodiment, the step of crushing the battery may be performed under conditions of supplying an inert gas, carbon dioxide, nitrogen, water, or a combination thereof, or under a vacuum atmosphere of 100 torr or less. For example, when the step of freezing the battery is performed by cooling at a temperature range of −60 to −20° C., when performed under the above conditions, oxygen supply is suppressed to prevent the electrolyte from reacting with oxygen, thereby preventing an explosion, suppressing vaporization of the electrolyte, and preventing the generation of flammable gases such as ethylene, propylene, or hydrogen.

[0074] In one embodiment, the step of crushing the battery may be performed so that the maximum size of the crushed battery fragments is 100 mm or less. Specifically, the size of the crushed battery fragments may be 50 mm or less. If the maximum size of the crushed battery fragments is 100 mm or more, as the crushed battery fragments are crushed, the heat generated due to instability may rise to a temperature range of 120°C, which is the average vaporization temperature of the electrolyte, and stability issues such as fire may occur.

[0075] In one embodiment, the step of freezing the battery may satisfy the following formula 1: <Expression 1> Minimum cooling time (Hr)=A×(W 0.33 ) (A=4×e (-0.02×dT) , W = battery weight (kg), dT = |external cooling temperature - target temperature|, || means absolute value)

[0076] In Equation 1, W represents the weight of the battery, e.g., the weight of a battery pack, a single battery, or a combination thereof. The minimum cooling time represents the external cooling temperature applied to the battery, e.g., the target temperature for cooling the electrolyte in the battery.

[0077] The step of freezing the battery has an advantage that the electrolyte inside the battery is cooled by performing the step for a minimum cooling time or more, thereby enabling subsequent processes to be performed stably. However, if the step of freezing the battery has a problem that the electrolyte is not cooled and there is a risk of fire when the battery is crushed if the battery is frozen for a time shorter than the minimum cooling time. [Example]

[0078] Preferred examples and comparative examples of the present invention will be described below. However, the following examples are merely preferred embodiments of the present invention, and the present invention is not limited to the following examples.

[0079] <Battery internal temperature according to minimum freezing time> The battery pack used in the example was not frozen and was crushed using the same crusher as in the example. During the crushing process, a flame occurred due to a short circuit, as shown in Figures 3a and 3b.

[0080] As described above, through the examples and comparative examples, it can be confirmed that by including a step of freezing the battery pack including the batteries before crushing the batteries, no short circuit occurs, no flame occurs, and excellent stability is achieved in the battery crushing step.

[0081] FIG. 1 is a diagram showing the change in battery voltage with cooling temperature according to one embodiment of the present invention. Referring to Figure 1, when the battery voltage was measured while the battery was frozen at -80°C, the battery pack showed almost the same voltage at high temperatures of about 40°C, room temperature, and up to -60°C, confirming that the battery characteristics were not lost. Next, it was confirmed that the voltage dropped sharply when the temperature dropped from -60°C to -70°C, and the voltage became 0 below -70°C. Thus, it was confirmed that no short circuit occurred when the battery was frozen at temperatures between -60 and -150°C.

[0082] FIG. 2 is a graph showing the relationship between battery weight, external cooling temperature, and cooling time according to one embodiment of the present invention. Referring to FIG. 2, it can be seen that the battery treatment method according to one embodiment of the present invention can derive a minimum cooling time for cooling a battery in the step of freezing the battery. Specifically, it can be seen that the minimum cooling time is related to the battery weight, external cooling temperature, and target temperature. Specifically, the external cooling temperature and minimum cooling time are shown when the target temperature is set to -70°C and the battery weights are 2.5 kg (A), 10 kg (B), 20 kg (C), and 50 kg (D), respectively. When cooling a battery, it can be seen that the battery electrolyte begins to cool after a predetermined time, and the voltage becomes zero. This confirms that a minimum maintenance time is required to sufficiently cool the battery interior, specifically the electrolyte.

[0083] Specifically, when the specific heat of the battery itself is taken into account in the heat transfer situation for cooling in which heat is taken to the outside, it is possible to confirm the battery weight and the time required for cooling. In this way, in order to cool the battery, the present invention can confirm the minimum time required for cooling by using the external cooling temperature for refrigeration, the target temperature, and the battery weight.

[0084] Table 1 below shows the minimum cooling time depending on the battery weight and external cooling temperature.

[0085] [Table 1]

[0086] From Table 1, it can be seen that the smaller the battery weight, the shorter the minimum cooling time for the battery to be cooled. Furthermore, it can be seen that when the value of Equation 1, derived from the relationship between the battery weight, external cooling temperature, and target temperature, is used to cool the battery for the minimum cooling time, it is possible to cool the battery, specifically the electrolyte of the battery. Furthermore, when the battery is cooled for a time equal to or longer than the value of Equation 1, no fire occurs during the subsequent process of crushing the battery. Figures 3a and 3b are photographs of a comparative example of the present invention in which a fire occurred when the battery was crushed after being frozen for a shorter time than the minimum cooling time. Figures 3c and 3d are photographs of an example in which no fire occurred when the battery was crushed after being frozen for a longer time than the minimum cooling time, according to an embodiment of the present invention.

[0087] 3a and 3b, an experiment was conducted to determine the fire risk of crushed batteries when they were frozen for less than the minimum required cooling time. In this experiment, the battery weight was 25 kg, the external cooling temperature was -95°C, and the target freezing temperature was -70°C. When the value of Equation 1 below is 7 hours, the experiment was conducted for 5 hours, which is shorter than the value of Equation 1. <Expression 1> Minimum cooling time = A × (W 0.33 ) (A=4×e (-0.02×dT) , W = battery weight (kg), dT = |external cooling temperature - target temperature|, || means absolute value)

[0088] Figures 3c and 3d show an experiment on the fire occurrence state of crushed batteries when the batteries were frozen for longer than the minimum freezing time required for cooling. The experiment was conducted with the same battery weight, external cooling temperature, and minimum freezing time as Figures 3a and 3b, and was conducted for 7 hours or more.

[0089] Table 2 below compares the fire occurrence status of the Example and Comparative Example, with the same battery weight, external cooling temperature, and minimum freezing time, as shown in Figures 3a to 3d. The fire occurrence status was judged as "O" if a fire was observed after crushing the battery, and "X" if not.

[0090] [Table 2]

[0091] From Table 2, it can be seen that if the battery is cooled at a value smaller than the value in Equation 1, which corresponds to the minimum cooling time, the electrolyte will not be cooled down and a fire will break out after the battery is crushed. As such, it can be seen that if the battery is cooled using the value in Equation 1 as the minimum cooling time, the crushed battery can be stably reused without a fire breaking out after being crushed.

[0092] <Battery crushing heat treatment> The step of calcining the crushed battery material was a dry heat treatment under conditions of a temperature range of 1,150 to 1,350°C and an oxygen concentration of 5 vol% or less. Specifically, the calcination heat treatment in this experiment was a dry heat treatment under conditions of a temperature range of 1,200 to 1,300°C, specifically, approximately 1,250°C, and an oxygen concentration of approximately 3 vol% or less.

[0093] The size of the crushed battery material produced after the dry heat treatment is 10 to 20 mm based on the long axis among the width, length, and height, the graphite content is 5% or more, and the content of plastic or iron impurities such as Al covers and PCB substrates in the crushed material is less than 5%.

[0094] <Control of valuable metal reactant recovery method> After the high-temperature reduction reaction, the components contained in the produced product include NCM alloy, lithium compounds, graphite, and other residual impurities such as copper and aluminum.

[0095] Comparative Example After the high-temperature reduction reaction, the produced product was classified to extract graphite, which was then subjected to magnetic separation.

[0096] Example After the high-temperature reduction reaction, the produced product is magnetically separated to separate valuable metal-containing materials including magnetic substances from valuable metal-containing materials including non-magnetic substances, and then additional crushing and sorting processes are carried out taking into account the constituent components of each of the magnetic and non-magnetic substances. Graphite is then extracted by classification.

[0097] Table 3 below shows the lithium content in graphite according to the order of graphite classification and magnetic separation.

[0098] [Table 3]

[0099] As seen in Table 3, when the magnetic separation step is performed before the classification step, as in the examples, the first lithium compound in the first valuable metal-containing material is simultaneously recovered as a third valuable metal-containing material with the first lithium compound disposed on its surface, which is advantageous for lithium recovery. As in the comparative example, when the classification step is performed before the magnetic separation step, the first lithium compound contained in the first valuable metal-containing material is separated along with the graphite, making lithium recovery difficult. Because graphite does not dissolve when leached in acid, it undergoes a separate separation process, which also separates lithium, resulting in a reduced lithium recovery rate during the leaching process. Table 4 below shows the content of reactants recovered according to the order of graphite classification and magnetic separation, as determined by magnetic classification.

[0100] [Table 4]

[0101] As shown in Table 4, it was confirmed that the composition ratios of Ni-Co-Mn, Li, and C, which are components of the input crushed material, after the high-temperature reaction differed depending on whether magnetic separation was performed after classification or classification after magnetic separation, as shown in Table 4. When classification was performed first, as in the comparative examples, the lithium content in the first valuable metal-containing material of Comparative Example 1 or 2 was approximately 0.8 to 1.1 wt%, specifically 0.84 wt% and 1.07 wt%, while when magnetic separation was performed first, the lithium content in the first valuable metal-containing material of Example 1 or 2 was approximately 6 to 8 wt%, specifically 6.21 wt% and 7.39 wt%. It was confirmed that when classification was performed after magnetic separation, there was little loss of lithium compounds and the lithium content in the first valuable metal-containing material was higher than 1.5 wt%.

[0102] Specifically, it was confirmed that the lithium content in the second valuable metal-containing material of Comparative Example 1 or 2 was approximately 9 to 11 wt%, while the lithium content in the second valuable metal-containing material of Example 1 or 2 was approximately 0.5 to 1.5 wt%, specifically 0.57 wt% and 1.45 wt%, which was approximately 6 to 20 times lower.

[0103] It was confirmed that the Ni-Co-Mn content in the second valuable metal-containing material in the comparative example and the example was at a similar level of 0.5 to 3 wt%.

[0104] In contrast, the graphite content in the second valuable metal-containing material in the comparative example was found to be about 10% lower than in the example. This is believed to be due to the detachment and dispersion of some of the Li compounds that had adhered to the magnetic material during classification. As can be seen from Table 4, in the case of lithium compounds mixed with graphite, the high graphite content can reduce the leaching efficiency during the acid leaching process, potentially resulting in a lower lithium recovery rate.

[0105] <First step of crushing valuable metal-containing materials> The magnetically separated first valuable metal-containing material was crushed into particles of 500 to 1000 μm using an attrition mill to separate the NCM alloy and the lithium compound LiAlO2 attached to the surface of the NCM alloy. The component ratios of the NCM alloy and the lithium compound are shown in Table 5 below.

[0106] [Table 5]

[0107] Table 5 shows the weight percentages of the main components when the first valuable metal-containing material is crushed to a particle size of 500 to 1000 μm. It was confirmed that the first lithium compound attached to the surface of the third valuable metal-containing material, including NCM, had a high Li content when crushed to a particle size of 500 to 1000 μm during the crushing step. This confirms that when the first lithium compound is separated after crushing the first valuable metal-containing material, the Li content of the reactant contained in the subsequent process increases. Furthermore, when applied to the subsequent process, the first lithium compound contains only a trace amount of graphite, eliminating the need for a separate graphite separation step, which shortens the processing time and is therefore economical.

[0108] Although the preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts defined in the claims below also fall within the scope of the present invention.

Claims

1. A valuable metal reactant containing valuable metals recovered from waste batteries, a first valuable metal-containing material containing magnetic material; Secondary valuable metal-containing materials containing non-magnetic substances; carbon compounds containing carbon; and Contains other residual impurities, The first valuable metal-containing material includes a third valuable metal-containing material and a first lithium compound attached to a surface of the third valuable metal-containing material, The lithium content of the first lithium compound is 1.5% by weight or more of lithium in the first valuable metal-containing material.

2. The first lithium compound is LiAlO ２ and Li ２ CO ３ , LiF, and Li ５ AlO ４ The valuable metal reactant according to claim 1, comprising a lithium compound containing at least one of the following:

3. The second valuable metal-containing material contains a second lithium compound, The valuable metal reactant according to claim 1, wherein the lithium content of the second lithium compound is less than 20% by weight in the second valuable metal-containing material.

4. The second lithium compound is LiAlO ２ and Li ２ CO ３ , LiF, and Li ５ AlO ４ The valuable metal reactant according to claim 3, comprising a lithium compound containing at least one of the following:

5. The valuable metal reactant according to claim 1, wherein the third valuable metal-containing material contains at least one of cobalt, nickel, and manganese.

6. The valuable metal reactant according to claim 1, wherein the second valuable metal-containing material contains at least one of a second lithium compound, aluminum, aluminum oxide, copper, copper oxide, manganese, and manganese oxide.

7. A valuable metal crushed product produced by crushing the valuable metal reactant according to any one of claims 1 to 6.

8. The valuable metal crushed material according to claim 7, having an average particle size of 100 to 4000 μm.

9. a high-temperature reduction step in which the crushed battery material is subjected to a high-temperature reduction reaction to obtain a valuable metal reactant; a magnetic separation step of separating the valuable metal reactant into a first valuable metal-containing material containing a magnetic substance and a second valuable metal-containing material containing a non-magnetic substance; and A first separation step of separating the second valuable metal-containing material into a carbon-containing material containing carbon and a second lithium compound, The first valuable metal-containing material includes a third valuable metal-containing material and a first lithium compound attached to a surface of the third valuable metal-containing material, A method for recovering valuable metals, wherein the lithium content of the first lithium compound is 1.5% by weight or more in the first valuable metal-containing material.

10. 10. The valuable metal recovery method according to claim 9, further comprising a second separation step of separating the first valuable metal-containing material into a third valuable metal-containing material and the first lithium compound.

11. The valuable metal recovery method according to claim 10 , wherein the second separation step includes a step of desorbing the first lithium compound attached to the surface of the third valuable metal-containing material.

12. The valuable metal recovery method according to claim 10, wherein the second separation step includes a step of crushing the first valuable metal-containing material to an average particle size of 100 to 4000 μm.

13. The valuable metal recovery method according to claim 9, wherein the lithium content of the second lithium compound is less than 20% by weight in the second valuable metal-containing material.

14. 10. The valuable metal recovery method according to claim 9, wherein the second valuable metal-containing material contains at least one of aluminum, aluminum oxide, copper, copper oxide, manganese, and manganese oxide.

15. The valuable metal recovery method according to claim 9, wherein the third valuable metal-containing material includes an alloy or oxide containing at least one of cobalt, nickel, and manganese.

16. The valuable metal recovery method according to claim 9, wherein the first separation step is carried out by particle size separation.

17. After the high temperature reduction step and before the magnetic separation step, The valuable metal recovery method according to claim 9, wherein the step of removing impurities further comprises a step of removing impurities by particle size separation in the range of 5 to 10 mm.

18. Before the high-temperature reduction reaction step, The valuable metal recovery method according to claim 9, further comprising a step of freezing the batteries that are the base material for the crushed batteries.

19. The valuable metal recovery method according to claim 18, wherein the step of freezing the battery satisfies the following formula 1: <Formula 1> Minimum cooldown time (Hr) = A × (W) ０．３３ ) (A = 4 × e （－０．０２×ｄＴ） , W = battery weight (kg), dT = |external cooling temperature-target temperature|, ∥ denotes an absolute value)

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