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

Abstract

The present invention relates to a valuable metal reactant, a valuable metal crushed product, and a valuable metal recovery method, the valuable metal reactant of the present invention being a valuable metal reactant containing a valuable metal recovered from a waste battery, the present invention relates to a lithium ion secondary battery comprising a first valuable metal-containing substance containing a magnetic material, a second valuable metal-containing substance containing a non-magnetic material, a carbon-containing carbon compound, and remaining other impurities, the first valuable metal-containing substance comprising a third valuable metal-containing substance and a first lithium compound adhering to the surface of the third valuable metal-containing substance, the lithium content of the first lithium compound may be 1.5% or more by weight of lithium contained in the first valuable metal-containing substance.

Description

Technical Field

[0001] The present invention relates to waste batteries, and more particularly to valuable metal reactants, valuable metal fragments, and a valuable metal recovery method obtained by recycling waste batteries. Background Art

[0002] With the increasing global demand for electric vehicles, how to handle the waste batteries generated by these vehicles has become a social issue. For lithium secondary batteries, which are the main raw material of the waste batteries, they contain organic solvents, explosive substances, and heavy metal substances such as Ni, Co, Mn, and Fe. However, Ni, Co, Mn, and Li are valuable metals with great scarcity value, and the recycling and reuse processes of lithium secondary batteries after being discarded have become an important research field.

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

[0004] In order to utilize the waste batteries, people are becoming more and more interested in the waste battery reuse process, which crushes the waste batteries to produce intermediate materials such as waste battery fragments or black powder, and then recovers valuable metals through subsequent processes.

[0005] Specifically, the main components of waste batteries are composed of expensive valuable metal elements such as Ni, Co, Mn, and Li. The waste batteries refer to batteries with a full service life, such as secondary batteries with a service cycle of 5 to 10 years. From the perspectives of environmental protection and cost, the reuse of the main components of waste batteries is crucial. The waste batteries are processed by conventional crushing, pulverization, or specific gravity screening to produce a mixture of positive and negative electrode materials in the form of black powder as an intermediate product. The valuable metals required for battery production are recovered from the black powder thus produced through wet processes such as leaching, solvent extraction, or crystallization. Thereby, the raw material supply can be made smooth, and the battery manufacturing cost can be greatly reduced.

[0006] In the screening process of reactants that have undergone calcination heat treatment through a waste battery recycling method, a method of first separating graphite and then performing magnetic separation to recover valuable metals has been studied. However, if the graphite is separated first, the graphite is mixed with a large amount of particulate lithium compounds such as LiAlO2, Li2CO3, LiF, or Li5AlO4, etc. During the post-treatment screening process of removing the graphite, the lithium compounds are included together, resulting in a loss of lithium content entering the subsequent process and a problem of decreased lithium recovery rate. Summary of the Invention

[0007] Technical Problem to be Solved

[0008] According to an embodiment of the present invention, a valuable metal reactant provides a reactant with a relatively high recovery rate of valuable metals (especially lithium) during the recovery of valuable metals in subsequent processes.

[0009] According to another embodiment of the present invention, a valuable metal fragment is made by crushing the valuable metal reactant having the aforementioned advantages, providing a fragment with a relatively high recovery rate of valuable metals.

[0010] According to still another embodiment of the present invention, a method for recovering valuable metals having the aforementioned advantages provides a method for recovering valuable metals with excellent recovery rate of valuable metals.

[0011] Technical Solution

[0012] A valuable metal reactant according to an embodiment of the present invention is a valuable metal reactant containing valuable metals recovered from waste batteries, which includes: a first valuable metal-containing substance containing a magnetic material, a second valuable metal-containing substance containing a non-magnetic material, a carbon compound containing carbon, and residual other impurities. The first valuable metal-containing substance includes a third valuable metal-containing substance and a first lithium compound attached to the surface of the third valuable metal-containing substance. The lithium content of the first lithium compound may be 1.5% or more of lithium contained by weight in the first valuable metal-containing substance. In one embodiment, the first lithium compound may include LiAlO2; and a lithium compound including at least any one of Li2CO3, LiF, and Li5AlO4.

[0013] In one embodiment, the second valuable metal-containing substance includes a second lithium compound, and the lithium content of the second lithium compound may be less than 20% by weight of lithium contained by weight in the second valuable metal-containing substance. In one embodiment, the second lithium compound may include LiAlO2; and at least any one of Li2CO3, LiF, and Li5AlO4.

[0014] In one embodiment, the third valuable metal inclusion may contain at least one of cobalt, nickel, and manganese. In one embodiment, the second valuable metal inclusion may contain at least one of a second lithium compound, aluminum, aluminum oxide, copper, copper oxide, manganese, and manganese oxide.

[0015] The valuable metal fragment according to another embodiment of the present invention may be formed by crushing the foregoing valuable metal reactant. In one embodiment, the valuable metal fragment may have an average particle size of 100 to 4000 μm.

[0016] A valuable metal recovery method according to still another embodiment of the present invention includes: a high-temperature reduction step of performing a high-temperature reduction reaction on the battery fragment to obtain a valuable metal reactant; a magnetic separation step of separating the valuable metal reactant into a first valuable metal inclusion containing a magnetic material and a second valuable metal inclusion containing a non-magnetic material; and a first separation step of separating the second valuable metal inclusion into a carbon-containing carbon inclusion and a second lithium compound. The first valuable metal inclusion includes a third valuable metal inclusion and a first lithium compound attached to the surface of the third valuable metal inclusion. The lithium content of the first lithium compound may be 1.5% or more of lithium contained in the first valuable metal inclusion by weight.

[0017] In one embodiment, it may include a second separation step of separating the first valuable metal inclusion into a third valuable metal inclusion and the first lithium compound.

[0018] In one embodiment, the step of crushing and separating the first valuable metal inclusion into a third valuable metal inclusion and the first lithium compound may include a step of detaching the first lithium compound attached to the surface of the first valuable metal inclusion.

[0019] In one embodiment, the second separation step may include a step of crushing the first valuable metal inclusion into 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% by weight of lithium contained in the second valuable metal inclusion.

[0020] In one embodiment, the second valuable metal inclusion may contain at least one of aluminum, aluminum oxide, copper, copper oxide, manganese, and manganese oxide. In one embodiment, the third valuable metal inclusion may contain an alloy or oxide containing at least one of cobalt, nickel, and manganese.

[0021] In one embodiment, the first separation step can be carried out by particle size separation. In one embodiment, after the high-temperature reduction step and before the magnetic separation step, the step of removing impurities may further include an impurity removal step of removing impurities by particle size separation in the range of 5 to 10 mm. In one embodiment, before the high-temperature reduction reaction step, a step of freezing the battery as the base material of the battery crushed material may further be included.

[0022] In one embodiment, the step of freezing the battery may satisfy the following formula 1.

[0023] <Formula 1>

[0024] Minimum cooling time (hours) = A × (W 0.33 )

[0025] A = 4 × e (-0.02×dT) , W = battery weight (Kg), dT = │external cooling temperature - target temperature│, ││ represents the absolute value.

[0026] Advantageous Effects

[0027] The valuable metal reactant according to an embodiment of the present invention provides a reactant with a high recovery rate of valuable metals (especially lithium) in the subsequent process of recovering valuable metals.

[0028] The valuable metal crushed material according to another embodiment of the present invention is made by crushing the valuable metal reactant having the aforementioned advantages, and provides a crushed material with a high recovery rate of valuable metals.

[0029] According to still another embodiment of the present invention, the valuable metal recovery method provides a valuable metal recovery method having the aforementioned advantages. Description of the Drawings

[0030] Figure 1 is a graph of the minimum cooling time according to an embodiment of the present invention.

[0031] Figure 2 is a graph showing the relationship between the battery weight, the external cooling temperature, and the cooling time according to an embodiment of the present invention.

[0032] Figure 3a And 3b is a photograph of a comparative example where a fire occurs during crushing after freezing (time shorter than the minimum cooling time), Figure 3c And 3d is a photograph of an example where no fire occurs during crushing after freezing (time longer than the minimum cooling time) according to the embodiment. Detailed Description of the Invention

[0033] The terms first, second, third, etc. are used to describe various parts, components, regions, layers, and / or segments, but these parts, components, regions, layers, and / or segments should not be limited by these terms. These terms are only used to distinguish one part, component, region, layer, or segment from another part, component, region, layer, or segment. Thus, without departing from the scope of the present invention, the first part, component, region, layer, or segment described below may also be described as the second part, component, region, layer, or segment.

[0034] The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the present invention. Unless the context clearly dictates otherwise, the singular forms used herein are also intended to include the plural forms. The use of "comprising" in the specification may specifically refer to a certain characteristic, field, integer, step, action, element, and / or component, but does not exclude the existence or addition of other characteristics, fields, integers, steps, actions, elements, and / or components.

[0035] If a part is described as being above another part, there may be other parts directly above the other part or there may be other parts therebetween. When a part is described as being directly above another part, there are no other parts therebetween.

[0036] Although not otherwise defined, the meanings of all terms (including technical and scientific terms) used herein are the same as those commonly understood by a person of ordinary skill in the art to which the present invention pertains. For terms defined in a dictionary, they should be interpreted as having a meaning consistent with the relevant technical literature and the content disclosed herein, and should not be interpreted in an idealized or overly formal sense.

[0037] Hereinafter, embodiments of the present invention will be described in detail. However, the following embodiments are given only by way of example, and the present invention is not limited to the following embodiments. The present invention is only defined by the scope of the claims.

[0038] A valuable metal reactant according to an embodiment of the present invention is a valuable metal reactant containing valuable metals recovered from waste batteries, which 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 residual impurities. The valuable metal reactant refers to the reactant after a high-temperature reduction reaction is performed on battery crushings in the following valuable metal recovery method, followed by magnetic separation, and then the carbon compound such as graphite is extracted from the second valuable metal-containing material.

[0039] In one embodiment, the first valuable metal inclusion may include a third valuable metal inclusion and a first lithium compound attached to the surface of the third valuable metal inclusion. The valuable metal reactant is a reactant generated in a step before crushing the first valuable metal inclusion in the following valuable metal recovery method, and may include the third valuable metal inclusion alone, or the third valuable metal inclusion in a state where the first lithium compound is attached to the surface thereof.

[0040] In one embodiment, the third valuable metal inclusion in the first valuable metal inclusion may include at least one of cobalt, nickel, and manganese. In one embodiment, the second valuable metal inclusion may include at least one of a second lithium compound, aluminum, aluminum oxide, copper, copper oxide, manganese, and manganese oxide.

[0041] In one embodiment, the first lithium compound may be a composition including LiAlO2; and a lithium compound including at least any one of Li2CO3, LiF, and Li5AlO4. In one embodiment, the lithium content of the first lithium compound may be 1.5% or more lithium by weight in the first valuable metal inclusion. Specifically, the lithium content of the first lithium compound may be 1.8% to 9.0% lithium by weight in the first valuable metal inclusion, and more specifically 6.21 to 7.39% lithium.

[0042] If the lithium content of the first lithium compound in the first valuable metal inclusion is within the foregoing range, it is less affected by graphite leaching in subsequent processes, and the lithium recovery rate can be increased. If the lithium content of the first lithium compound in the first valuable metal inclusion is not within the foregoing range, it is more affected by graphite leaching, and there is a problem of a decrease in the lithium recovery rate.

[0043] In one embodiment, the lithium content of the second lithium compound may be less than 20% lithium by weight in the second valuable metal inclusion. Specifically, the lithium content of the second lithium compound may be 9.0% or less, 6.0% or less, and more specifically 1.45% or less lithium by weight in the second valuable metal inclusion. The lithium content of the second lithium compound may exceed 0% in the second valuable metal inclusion. This is because as the valuable metal inclusion undergoes a classification process after magnetic screening, lithium will inevitably be mixed in.

[0044] By making the lithium content of the second lithium compound in the second valuable metal inclusion satisfy the aforementioned range, there is an advantage of being able to reduce the content of the lithium compound lost together with graphite during classification. If the lithium content of the second lithium compound in the second valuable metal inclusion exceeds the aforementioned range, it is greatly affected by graphite leaching in the subsequent process, and there is a problem of a decrease in lithium recovery rate.

[0045] The valuable metal fragment according to another embodiment of the present invention may be formed by crushing the aforementioned valuable metal reactant. Specifically, the valuable metal fragment may be made via a crushing step that is performed to separate a third valuable metal inclusion having a first lithium compound disposed on its surface from the first valuable metal inclusion of the aforementioned valuable metal reactant.

[0046] More specifically, the valuable metal fragment may include the crushed third valuable metal inclusion and the first lithium compound. In one embodiment, the valuable metal fragment may have an average particle size of 100 to 4000 μm.

[0047] A valuable metal recovery method according to another embodiment of the present invention includes: a high-temperature reduction step of performing a high-temperature reduction reaction on a battery fragment; a magnetic separation step of separating the reactant generated after the high-temperature reduction reaction into a first valuable metal inclusion containing a magnetic material and a second valuable metal inclusion containing a non-magnetic material to separate the valuable metal inclusions; and a first separation step of separating a carbon-containing carbon inclusion and the valuable metal inclusion from the product obtained after the magnetic separation step.

[0048] The battery fragment refers to the material that is the base material of the battery fragment or the fragmented material itself. The base material of the battery fragment may include an end-of-life battery, a waste battery, and waste generated during the manufacturing process of a lithium-ion battery. Specifically, the waste battery may include scraps, jellyrolls, and slurry, etc., which are positive electrode materials constituting the waste battery, defective products generated during the manufacturing process, residues during the manufacturing process, and generated scraps. For the base material of the battery fragment, it is subsequently made into a battery fragment via a crushing process.

[0049] The fragmented material itself may be a fragmented product itself such as black powder. As described above, by reusing waste batteries to manufacture battery fragments, there are environmental and economic advantages.

[0050] The step of performing a high-temperature reduction reaction on the battery crushed material is the step of putting the battery crushed material into a heating furnace (Furnace) capable of heating up to a high temperature to raise the temperature of the battery crushed material to a temperature above the melting point. The step of performing a high-temperature reduction reaction on the battery crushed material may be accompanied by heat treatment conditions for the high-temperature reduction reaction and does not need to go through a melting step.

[0051] In one embodiment, the step of performing a high-temperature reduction reaction on the battery crushed material may be carried out in a temperature range of 1150 to 1350 °C. In one embodiment, the step of performing a high-temperature reduction reaction on the battery crushed material may be carried out under the condition of 5% by volume or less of oxygen. By carrying out the high-temperature reduction reaction under this condition, there are advantages of improving the lithium recovery rate and reducing CO2 emissions.

[0052] The magnetic separation step of separating the reactant generated 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 is a step of separating the first valuable metal-containing material containing a magnetic material and the second valuable metal-containing material containing a non-magnetic material (specifically composed of non-magnetic materials) by magnetic separation. For the magnetic separation, for example, by using a magnetic body, particles can be separated by contact with the magnetic body, and various magnetic separation methods can be adopted.

[0053] When performing the magnetic separation, the first valuable metal-containing material containing magnetic materials such as cobalt can be separated by screening, and the materials other than the first valuable metal-containing material that do not contain magnetic materials can be separated into the second valuable metal-containing material.

[0054] 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 contain cobalt, nickel, manganese or their oxides as the containing material itself; an alloy containing at least two of cobalt, nickel, and manganese or their oxides.

[0055] In one embodiment, at least a part of the first valuable metal-containing material may be included as a containing material in a state where the third valuable metal-containing material and the first lithium compound are arranged on the surface of the third valuable metal-containing material. Specifically, the first valuable metal-containing material may be composed of a separate third valuable metal-containing material or the first valuable metal-containing material and the first valuable metal-containing material with the first lithium compound arranged on the surface. As described above, by magnetic separation, the first valuable metal-containing material with the first lithium compound arranged on the surface is preferentially screened out, thereby preventing the lithium compound from detaching from the first valuable metal-containing material in subsequent particle size separation, and having the advantage of being able to increase the lithium recovery rate.

[0056] The second valuable metal-containing material may include at least one of aluminum, aluminum oxide, copper, copper oxide, manganese, and manganese oxide. For the second valuable metal-containing material, as a valuable metal-containing material containing a non-magnetic material, materials such as LiAlO2, Cu, and MnO may be included, for example. 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, for the first lithium compound, it may be, for example, lithium aluminum oxide LiAlO2.

[0057] The first separation step of separating the carbon-containing material containing carbon and the second lithium compound from the second valuable metal-containing material obtained after the magnetic separation step includes the step of separating the carbon-containing material (specifically, graphite) from the second valuable metal-containing material containing a non-magnetic material obtained after the magnetic separation step. In one embodiment, the step of separating the graphite may be performed by any one of particle size separation and specific gravity separation.

[0058] In one embodiment, for any one of the particle size separation and specific gravity separation, means such as a cyclone separator or a flotation device may be used for separation, for example. Specifically, in order to separate the graphite, it may be based on 100 μm. For the graphite, it may be separated by particle size separation within the range of 100 μm or less.

[0059] As described above, after the magnetic separation step, the obtained second valuable metal-containing material undergoes a classification process to separately separate the graphite. Compared with the case where the process of separating the graphite is performed first, the problem of lithium loss caused by fine lithium compounds included in the process of removing and screening the graphite can be solved, and it has the advantage of being able to increase the lithium content added in the subsequent process.

[0060] As described above, after the magnetic separation is performed first, in the reactant where the graphite is separately separated by classification, the lithium content of the first lithium compound may be 1.5% or more of lithium contained by weight in the first valuable metal-containing material. Specifically, the lithium content of the first lithium compound may be 6% or more of lithium contained by weight in the first valuable metal-containing material.

[0061] As described above, relative to the classification step, the magnetic screening step is performed first, so as to simultaneously recover the third valuable metal-containing material having the first lithium compound disposed on the surface in the first valuable metal-containing material, and it is less affected by the leaching of graphite in the subsequent process, and has the advantage of being able to increase the lithium recovery rate.

[0062] In one embodiment, the lithium content of the second lithium compound may be less than 20% lithium by weight 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% 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 lithium in the second valuable metal-containing material.

[0063] As described above, after the magnetic separation step, the obtained second valuable metal-containing material undergoes a classification process to separately isolate the graphite. Compared with the case where the process of separating the graphite is carried out first, it is possible to solve the problem of lithium loss caused by fine lithium compounds contained in the process of removing and screening the graphite, and has the advantage of being able to increase the lithium content added in the subsequent process.

[0064] In addition, the second lithium compound contains a large amount of lithium compounds in the additional screening process of removing the graphite, thereby preventing the problem of a decrease in the Li recovery rate of the second lithium compound in the subsequent process.

[0065] In one embodiment, after the step of separating the carbon-containing carbonaceous material and the second lithium compound from the product obtained after the magnetic separation step, a second separation step of separating the first valuable metal-containing material into a third valuable metal-containing material and a first lithium compound may be included.

[0066] 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 disposed on the surface of the valuable metal-containing material from the valuable metal-containing material.

[0067] For the second separation step, 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 third valuable metal-containing material and the first lithium compound can be separated. The second separation step is not limited to the aforementioned crushing method, and various methods can be used as long as the third valuable metal-containing material and the first lithium compound can be separated by an external force. As described above, by separating the lithium compound by physical external force, not only can the recovery rate of valuable metals such as nickel, cobalt, and manganese be improved, but also the recovery rate of lithium can be improved.

[0068] In one embodiment, the second separation step of crushing the first valuable metal-containing material into a third valuable metal-containing material and a first lithium compound may include a step of crushing the first valuable metal-containing material into an average particle size in the range of 100 to 4000 μm. Specifically, the crushing step may include a step of crushing into a range of 100 to 1000 μm. By the step of crushing into the aforementioned 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 containing NCM is high.

[0069] For the second separation step, if the crushing proceeds beyond the upper limit value of the range, the size of the Ni-Co-Mn alloy formed during the high-temperature heat treatment of the crushed material increases, and there is a problem of an increase in the leaching time in the subsequent wet process. For the second separation step, if the crushing proceeds beyond the lower limit value of the range, the size of the alloy formed by the crushed material below 100 μm during the high-temperature heat treatment decreases, so that graphite will be separated together during magnetic screening, and there is a problem of interference from graphite insoluble in acid during the leaching process, resulting in a process delay.

[0070] In one embodiment, the second separation step of crushing the first valuable metal-containing material into a third valuable metal-containing material and a first lithium compound may be carried out after the magnetic separation step of separating the reactant formed 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 to separate the valuable metal-containing materials. For the second separation step, for example, it may be carried out between the aforementioned magnetic separation step and the aforementioned graphite separation step, or may be carried out after the aforementioned magnetic separation step and the aforementioned graphite separation step. By carrying out the second separation step after the aforementioned magnetic separation step, there is an advantage of being able to prevent the aggregation of lumps such as flakes.

[0071] In one embodiment, before the magnetic separation step of separating the reactant formed 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 to separate the valuable metal-containing materials, a step of removing impurities may further be included. For the impurities, for example, they may be iron blocks, flakes and other impurities.

[0072] In one embodiment, the step of removing the impurities may be carried out by any one of magnetic screening, particle size separation and specific gravity separation. For the magnetic screening, a magnetic body having a magnetic field strength capable of separating iron blocks from valuable metal-containing materials such as NCM alloys may be used. For the particle size separation, by controlling the particle size, iron blocks can be separated. Specifically, the particle size is the average particle size, and for example, the particle size separation may be carried out based on a range of 5 to 10 mm or more.

[0073] Before the aforementioned magnetic separation, impurities are preferably removed to eliminate impurities that may affect magnetic screening, which has the advantage of increasing the recovery rate of valuable metals.

[0074] In one embodiment, before the step of subjecting the battery debris to a high-temperature reduction reaction, steps of freezing the battery and then crushing the frozen battery may be carried out first. By freezing the battery debris before crushing, it is possible to prevent the battery from catching fire during the crushing process.

[0075] The step of freezing the battery is carried out at a temperature sufficient to freeze the electrolyte contained in the battery. Specifically, for example, the freezing step may be carried out in a temperature range of -150 to -20°C. More specifically, the temperature range may be -150 to -50°C, and more specifically, it may be a temperature range of -80 to -60°C.

[0076] If the battery is frozen in the above temperature range, the trace residual voltage inside the battery (for example, a voltage of about 2V to 3V) drops to near 0V. Therefore, even if a short circuit occurs due to direct contact between the positive and negative electrodes, no battery reaction will occur, so the battery temperature will not increase, and thus no electrolyte gas will be generated and no combustion will occur. In addition, since the electrolyte is in a frozen state or a state where gasification is inhibited, the mobility of lithium ions is very low. Therefore, the electrical conduction characteristics based on the migration of lithium ions can be significantly reduced, and since no gasification of the electrolyte occurs, it is possible to avoid the generation of combustible gases such as ethylene, propylene, and hydrogen.

[0077] If the freezing process exceeds the above temperature range, for example, if it is cooled to a temperature higher than -60°C, the residual voltage inside the battery will not drop to 0V, and a battery reaction caused by a short circuit may occur, and the electrolyte will not be completely frozen, so it is not suitable. In addition, when cooled to -150°C, the electrolyte will be sufficiently frozen and the internal voltage of the battery will also drop to 0V. Therefore, there is no need to reduce the temperature to a lower level. As described above, the battery treatment method has the following advantages: before crushing a battery such as a lithium secondary battery, it includes a freezing step, which can prevent the fire risk that may occur in the battery crushing process.

[0078] The step of crushing the frozen battery may refer to a process of applying impact or compressive force to the battery to cause a part of the battery to fall off. In one embodiment, the step of crushing the battery may refer to a process of pulverizing the battery, a process of cutting the battery, a process of compressing the battery, and combinations thereof. Specifically, the crushing step may include all processes capable of breaking the battery to obtain small-sized debris.

[0079] In one embodiment, the step of crushing the battery may include compressing the frozen battery or applying an external force such as a shear force or a tensile force to break all the processes of the battery. For example, the step of crushing the battery may be implemented using a crusher.

[0080] In one embodiment, the step of crushing the battery may be performed at least once. Specifically, the crushing step may be performed continuously or discontinuously at least once.

[0081] In one embodiment, the step of crushing the battery may be implemented under the condition of supplying an inert gas, carbon dioxide, nitrogen, water or a combination thereof or under a vacuum environment condition of 100 Torr or less. For example, if the process of freezing the battery is implemented by cooling to a temperature range of -60 to -20 °C, if implemented under the foregoing conditions, by suppressing oxygen supply, the reaction of the electrolyte with oxygen can be prevented, and the explosion caused thereby can be prevented, and the vaporization of the electrolyte can also be suppressed, thereby avoiding the generation of combustible gases such as ethylene, propylene or hydrogen.

[0082] In one embodiment, the step of crushing the battery may be implemented until the maximum size of the battery fragments reaches 100 mm or less. Specifically, it may be implemented until the size of the battery fragments reaches 50 mm or less. If the maximum size of the battery fragments is 100 mm or more, as the battery fragments are broken, the heating temperature caused by instability will rise to the average vaporization temperature of the electrolyte (i.e., the temperature region of 120 °C), resulting in problems in terms of stability such as fire.

[0083] In one embodiment, the step of freezing the battery may satisfy the following formula 1.

[0084] <Formula 1>

[0085] Minimum cooling time (hours) = A × (W 0.33 )

[0086] A = 4 × e (-0.02×dT) , W = battery weight (Kg), dT = │external cooling temperature - target temperature│, ││ represents the absolute value.

[0087] W in the above formula 1 represents the weight of the battery, for example, the weight of a battery pack, a single battery or a combination thereof. The minimum cooling time represents the time required to cool the electrolyte in the battery to the target temperature by the cooling temperature applied to the battery (i.e., the external cooling temperature).

[0088] The step of freezing the battery is carried out for more than the minimum cooling time, so as to cool the electrolyte inside the battery, which has the advantage of being able to stably carry out subsequent processes. In the step of freezing the battery, if the freezing time of the battery is less than the minimum cooling time, the electrolyte will not be cooled, and there is a risk of fire during crushing.

[0089] Preferred embodiments and comparative examples of the present invention are described below. However, the following embodiments are only a preferred embodiment of the present invention, and the present invention is not limited to the following embodiments.

[0090] <Internal temperature of battery based on minimum freezing time>

[0091] Without freezing, the battery pack used in the embodiment is crushed using the same crusher as in the embodiment. As Figure 3a and Figure 3b shown, a flame caused by a short circuit occurred during the crushing process.

[0092] As described above, through the examples and comparative examples, it can be confirmed that since the step of freezing the battery pack containing the battery is included before the battery is crushed, no short circuit and flame occur during the battery crushing step, and it has excellent stability.

[0093] Figure 1 Shows the change in battery voltage based on the cooling temperature according to an embodiment of the present invention.

[0094] Referring to Figure 1 it can be confirmed that when the battery is frozen to -80°C and the battery voltage is measured, the battery pack exhibits almost the same voltage at a high temperature of about 40°C, normal temperature, and -60°C, so the battery characteristics are not lost. Then, if the temperature drops from -60°C to -70°C, the voltage will drop rapidly, and the result that the voltage reaches 0 at -70°C is confirmed. As described above, if the battery is frozen to -60 to -150°C, no short circuit will occur.

[0095] Figure 2 Is a graph showing the relationship between the battery weight, external cooling temperature, and cooling time according to an embodiment of the present invention.

[0096] Referring to Figure 2It can be confirmed that, according to an embodiment of the present invention, a battery processing method can derive the minimum cooling time for cooling a battery in the step of freezing the battery. Specifically, it can be confirmed that the minimum cooling time is related to the battery weight, the external cooling temperature, and the target temperature. Specifically, the figure shows the external cooling temperature and the minimum cooling time 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 the battery, after a predetermined time, it can be confirmed that the electrolyte of the battery starts to cool and the voltage becomes 0. Thus, it can be confirmed that when cooling the battery, a basic holding time is required to sufficiently cool to the inside (specifically, the electrolyte).

[0097] Specifically, it can be confirmed that in the heat transfer situation for cooling (where heat is taken to the outside), if the specific heat of the battery itself is considered, the battery weight and the time for cooling are required. As described above, in the present invention, in order to cool the battery, using the external cooling temperature and the target temperature for freezing, and the battery weight, the most basic time required for cooling can be confirmed.

[0098] The following Table 1 shows the minimum cooling time based on the battery weight and the external cooling temperature.

[0099]

Table 1

[0100]

[0101] It can be confirmed from the above Table 1 that the smaller the battery weight, the shorter the minimum cooling time required for the battery to be cooled. In addition, when cooling with the value of Equation 1 derived from the relationship based on the battery weight, the external cooling temperature, and the target temperature, that is, the minimum cooling time, it can be confirmed that the battery is cooled, specifically to the electrolyte of the battery. In addition, when the battery is cooled for a time longer than the value of Equation 1, no fire will occur during the subsequent battery crushing process. Figure 3a and Figure 3b are photos of a fire occurring during crushing after freezing (time shorter than the minimum cooling time) according to a comparative example of the present invention, Figure 3c and Figure 3d are photos of an example where no fire occurs during crushing after freezing (time longer than the minimum cooling time) according to an embodiment of the present invention.

[0102] Referring to Figure 3a and Figure 3b , the fire occurrence state of the crushed material was tested when the freezing time during battery cooling was less than the required minimum cooling time. In the experiment, when the battery weight was 25 kg, the external cooling temperature was -95°C, and the target freezing temperature was -70°C, if the value of the following Equation 1 was 7 hours, the experiment was carried out for 5 hours, which was less than the value of Equation 1 above.

[0103] <Formula 1>

[0104] Minimum cooling time = A × (W 0.33 )

[0105] A = 4 × e (-0.02×dT) , where W = battery weight (Kg), dT = │external cooling temperature - target temperature│, and ││ represents the absolute value.

[0106] Refer to Figure 3c and Figure 3d , the fire occurrence state of the debris was tested when the battery was frozen for a time longer than the minimum freezing time required for battery cooling. In the experiment, the battery weight, external cooling temperature were the same as Figure 3a and Figure 3b , and the minimum freezing time was more than 7 hours.

[0107] The following Table 2 compares the fire occurrence states of the examples and comparative examples based on the same battery weight, external cooling temperature, and minimum freezing time according to Figures 3a to 3d . For the judgment of the fire occurrence state, after the battery is broken, if a fire is observed, it is indicated as "O", and if no fire is observed, it is indicated as "X".

[0108]

Table 2

[0109]

[0110] It can be confirmed from Table 2 above that if the battery cooling time is less than the value of Formula 1 (equivalent to the minimum cooling time), the electrolyte will not be cooled, and a fire will occur after the battery is broken. As described above, if the battery is cooled with the value of Formula 1 as the minimum cooling time, after the battery is broken, the debris can be stably utilized and no fire will occur.

[0111] <Calcination heat treatment of battery debris>

[0112] The step of performing calcination heat treatment on the battery debris is carried out by dry heat treatment under the condition of 5% by volume or less of oxygen in the temperature range of 1150 to 1350 °C. Specifically, the calcination heat treatment of this experiment can be carried out by dry heat treatment in the temperature range of 1200 to 1300 °C, specifically about 1250 °C, and under the condition of about 3% by volume or less of oxygen.

[0113] After the dry heat treatment, based on the long axis in the horizontal, vertical, and height directions, the size of the manufactured battery debris is 10 to 20 mm, the graphite content is 5% or more, and the impurity content of plastics or iron blocks such as the aluminum cover and PCB substrate of the debris is less than 5%.

[0114] <Method for controlling the recovery of valuable metal reactants>

[0115] After the high-temperature reduction reaction, the components contained in the manufactured product include NCM alloy, lithium compounds, graphite, and other residual impurities such as copper and aluminum.

[0116] Comparative Example

[0117] After the high-temperature reduction reaction, the manufactured product is classified to extract graphite, and then magnetic screening is carried out.

[0118] Example

[0119] After the high-temperature reduction reaction, magnetic screening is carried out on the manufactured product to separate valuable metal inclusions containing magnetic materials and valuable metal inclusions containing non-magnetic materials. Considering the respective components of the magnetic and non-magnetic materials, further crushing and screening treatments are carried out. Subsequently, graphite is extracted by classification.

[0120] Table 3 below shows the lithium content in graphite according to the order of graphite classification and magnetic separation.

[0121]

Table 3

[0122]

[0123] It is confirmed from Table 3 above that, as described in the examples, when the magnetic screening step is carried out prior to the classification step, with the simultaneous recovery of the third valuable metal inclusion with the first lithium compound arranged on the surface in the first valuable metal inclusion, it is beneficial for lithium recovery. As described in the comparative example, when the classification step is carried out prior to the magnetic screening step, since the first lithium compound contained in the first valuable metal inclusion is separated together with graphite, it has been confirmed that lithium recovery is difficult. For graphite, it is insoluble in acid during leaching, so through a separate separation process, at this time, since lithium is also separated together, there is a problem of a decrease in the lithium recovery rate in the leaching process. Table 4 below shows the content of the reactants recovered according to the order of graphite classification and magnetic separation according to magnetic classification.

[0124]

Table 4

[0125]

[0126] It is confirmed from Table 4 above that the composition ratios of the components Ni-Co-Mn, Li, and C in the added crushed materials after high-temperature reaction are different depending on magnetic screening after classification or classification after magnetic screening, as shown in the content of Table 4 above. As described in the comparative examples, when classification is prioritized, the lithium content in the first valuable metal-containing material of Comparative Example 1 or 2 is about 0.8 to 1.1% by weight, specifically 0.84% to 1.07% by weight. When magnetic screening is prioritized, the lithium content in the first valuable metal-containing material of Example 1 or 2 is about 6 to 8% by weight, specifically 6.21% to 7.39% by weight. Therefore, when classification is carried out after magnetic screening, the loss of lithium compounds is less, and it has been confirmed that the lithium content in the first valuable metal-containing material is as high as more than 1.5% by weight.

[0127] Specifically, the lithium content in the second valuable metal-containing material of Comparative Example 1 or 2 is about 9 to 11% by weight, and the lithium content in the second valuable metal-containing material of Example 1 or 2 is about 0.5 to 1.5% by weight, specifically 0.57% to 1.45% by weight, which is about 6 to 20 times lower.

[0128] It has been confirmed that the content of Ni-Co-Mn in the second valuable metal-containing materials of the comparative examples and the examples is 0.5 to 3% by weight, showing similar levels.

[0129] In contrast, the graphite content in the second valuable metal-containing material of the comparative example is about 10% lower than that of the example. This is considered to be the result of part of the lithium compound attached to the magnetic body detaching and dispersing during classification. It can be confirmed from Table 4 that for the lithium compound mixed with graphite, a higher graphite content in the acid leaching process leads to a decrease in leaching efficiency, which may cause a reduction in lithium recovery rate.

[0130] <Crushing Step of the First Valuable Metal-Containing Material>

[0131] For the first valuable metal-containing material after magnetic separation, it is crushed within a particle size range of 500 to 1000 μm by an attrition mill to separate the NCM alloy and the lithium compound LiAlO2 attached to the surface of the NCM alloy. Then, the composition ratios of the NCM alloy and the lithium compound are shown in Table 5 below.

[0132]

Table 5

[0133]

[0134] As can be seen from Table 5 above, when the first valuable metal-containing material is crushed based on a particle size of 500 to 1000 μm, the weight percentage of the main components is shown. In the crushing step, when crushing is performed based on a particle size of 500 to 1000 μm, it has been confirmed that the Li content of the first lithium compound attached to the surface of the third valuable metal-containing material containing NCM is high. From this, it can be confirmed that when the first lithium compound is separated after the first valuable metal-containing material is crushed, the Li content of the reactants included in the subsequent process will increase. In addition, when applied to the subsequent process, only a trace amount of graphite is mixed in the first lithium compound, and there is no need for a separate graphite screening step, so the treatment process is shortened and economical.

[0135] The preferred embodiments have been described in detail above, but the scope of the rights of the present invention is not limited to the above embodiments, and various modifications and improvements made by those skilled in the art using the basic concepts defined in the claims also fall within the scope of the rights of the present invention.

Claims

1. A valuable metal reactant, which is a valuable metal reactant containing valuable metals recovered from waste batteries, and includes: A first valuable metal inclusion containing a magnetic material; A second valuable metal inclusion containing a non-magnetic material; A carbon compound containing carbon; and Residual other impurities, The first valuable metal inclusion includes a third valuable metal inclusion and a first lithium compound attached to the surface of the third valuable metal inclusion, The lithium content of the first lithium compound is 1.5% or more of lithium contained by weight in the first valuable metal inclusion.

2. The valuable metal reactant according to claim 1, wherein The first lithium compound includes LiAlO₂; and a lithium compound including at least any one of Li₂CO₃, LiF, and Li₅AlO₄.

3. The valuable metal reactant according to claim 1, wherein The second valuable metal inclusion includes a second lithium compound, The lithium content of the second lithium compound is less than 20% by weight of lithium contained by weight in the second valuable metal inclusion.

4. The valuable metal reactant according to claim 3, wherein The second lithium compound includes LiAlO₂; and a lithium compound including at least any one of Li₂CO₃, LiF, and Li₅AlO₄.

5. The valuable metal reactant according to claim 1, wherein The third valuable metal inclusion includes at least one of cobalt, nickel, and manganese.

6. The valuable metal reactant according to claim 1, wherein The second valuable metal inclusion includes at least one of a second lithium compound, aluminum, aluminum oxide, copper, copper oxide, manganese, and manganese oxide.

7. A valuable metal fragment, which is formed by crushing the valuable metal reactant according to any one of claims 1 to 6.

8. The valuable metal fragment according to claim 7, which has an average particle size of 100 to 4000 μm.

9. A valuable metal recovery method, which includes: A high-temperature reduction step of performing a high-temperature reduction reaction on a battery fragment to obtain a valuable metal reactant; A magnetic separation step of separating the valuable metal reactant into a first valuable metal inclusion containing a magnetic material and a second valuable metal inclusion containing a non-magnetic material; and A first separation step of separating the second valuable metal inclusion into a carbon-containing material containing carbon and a second lithium compound, The first valuable metal inclusion includes a third valuable metal inclusion and a first lithium compound attached to the surface of the third valuable metal inclusion, The lithium content of the first lithium compound is 1.5% or more of lithium contained by weight in the first valuable metal inclusion.

10. The valuable metal recovery method according to claim 9, which includes: A second separation step of separating the first valuable metal inclusion into a third valuable metal inclusion and the first lithium compound.

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

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 into 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 of lithium contained in the second valuable metal-containing material in terms of weight%.

14. The valuable metal recovery method according to claim 9, wherein, The second valuable metal-containing material includes 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. The valuable metal recovery method according to claim 9, wherein, After the high-temperature reduction step and before the magnetic separation step, The step of removing impurities further includes an impurity removal step of removing the impurities by particle size separation in the range of 5 to 10 mm.

18. The valuable metal recovery method according to claim 9, wherein, Before the high-temperature reduction reaction step, It further includes a step of freezing the battery that is the base material of the battery crushed material.

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 cooling time (hours) = A × (W 0.33 ) A = 4 × e (-0.02×dT) , where W = battery weight (Kg), dT = │external cooling temperature - target temperature│, and ││ represents the absolute value.

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