Composition for recovering lithium compounds, and battery treatment method

Abstract

The present invention relates to a composition for recovering lithium compounds and a battery treatment method. The battery treatment method of the present invention comprises the steps of: preparing a battery containing lithium (Li) and aluminum (Al); shredding the battery into battery shreds; and performing high-temperature heat treatment on the battery shreds, wherein the high-temperature heat treatment step includes a step of performing heat treatment at a temperature of 600-1,500°C and, in the step of preparing the battery, lithium and aluminum in the battery satisfy relation 1. <Relation 4> 0.1 ≤[Li] / [Al]≤ 1.0 (In relation 4, [Li] and [Al] represent the weight percentages (wt%) of lithium and aluminum in the battery.)

Description

Composition for recovering lithium compounds and method for processing batteries

[0001] The present invention relates to a composition for recovering valuable metals obtained by processing waste batteries and a method for processing batteries for the same.

[0002] As global demand for electric vehicles grows, the disposal of waste batteries generated from these vehicles is emerging as a social issue. Lithium secondary batteries, the primary raw material for these waste batteries, contain organic solvents, explosive materials, and heavy metals such as nickel, cobalt, manganese, and iron. However, nickel, cobalt, manganese, and lithium are valuable metals with high scarcity value. Therefore, the recovery and recycling processes for discarded lithium secondary batteries are emerging as a key research area.

[0003] Specifically, a lithium secondary battery is mainly composed of copper and aluminum used as a current collector, Li, Ni, Co, Mn-containing oxides constituting a positive electrode material, and graphite used as an anode material, and includes a separator separating the positive electrode material and the negative electrode material, and an electrolyte injected into the separator. The solvent used as a solvent and salt constituting the electrolyte is mainly a mixture of carbonate organic substances such as ethylene carbonate and propylene carbonate, and for example, LiPF6 is used.

[0004] The existing technology has dry and wet treatment processes. In the dry process, nickel-based molten metal is used for alloying. At this time, lithium is vaporized and volatilized in a high-temperature environment, or it forms a compound with the slag floating on the top of the molten metal, which has a low purity of less than 4%. At this time, the compound with the slag contains a lot of impurities such as lithium, aluminum, silicon, and calcium, and the cost of slag treatment becomes very high to deal with this. Specifically, there is a problem that the Ca and Si contents are very high when slag is formed through a process of alloying with molten metal in the existing dry process.

[0005] The above wet treatment process is actively being developed for a waste battery recycling process that crushes the waste batteries to produce intermediate materials such as waste battery shreds or black powder, and then recovers valuable metals through a post-process.

[0006] The recovered valuable metals are then subjected to acid leaching, a process that recovers valuable metals within the battery, such as Li, Ni, Co, and Mn. This process uses an acid, such as sulfuric acid, to ionize the valuable metals within the battery, and then removes impurities. After the impurities are removed, the Ni, Co, and Mn within the sulfuric acid are extracted in the form of sulfides through solvent extraction and crystallization.

[0007] After sulfuric acid leaching, the Li content in the sulfuric acid is approximately 6 to 10 g / L, but after solvent extraction and crystallization of Ni, Co, Mn, etc., the Li remaining in the sulfuric acid is diluted to approximately 1 to 2 g / L. In order to manufacture Li for battery manufacturing using a low-concentration Li-containing sulfuric acid solution, it goes through a multi-stage impurity removal and Li concentration process. The purity of battery-grade Li2CO3 or LiOH must be at least 99.5%, so high extraction costs are required to obtain a material with that purity, and there is a problem of low Li recovery rates, so research is needed to solve the above problems. On the other hand, in order to extract Li from Li-containing ores such as spodumene, which contains 1 to 3% Li, a large amount of precipitate is generated when heat-treated at 900 degrees Celsius or higher, followed by sulfuric acid leaching and impurity removal. 97 to 99% of the input precipitate is generated, and landfilling this precipitate requires high environmental treatment costs.

[0008] In this way, in the case of existing dry or wet processes, there is a problem of low lithium recovery rate, and in order to increase the lithium recovery rate, there is an excessive economic problem.

[0009] Most reaction methods convert waste batteries into black mass. This involves separating the aluminum and copper current collectors as much as possible, processing them into a powder of less than 0.1 mm in size, and then processing them at high temperatures. Lithium reacts very little with aluminum, reacting instead with the carbon in the black mass or with fluorine.

[0010] According to one embodiment of the present invention, a composition for recovering a lithium compound provides a composition having a high lithium content by reacting lithium in a waste battery with aluminum or aluminate, which is a positive electrode material of a current collector or battery, in a high purity manner.

[0011] According to another embodiment of the present invention, a method for processing a battery provides a method for processing a spent battery to obtain a composition for recovering a lithium compound having the advantages described above.

[0012] According to one embodiment of the present invention, a composition for recovering a lithium compound comprises a lithium compound recovered from a spent battery, and may have a prismatic shape. Specifically, when a polygon is drawn using parallel lines on the outside of the composition for recovering a lithium compound, the angle between the two outer lines may be at least one angle less than 90°.

[0013] In one embodiment, the composition for recovering a lithium compound may have a size in which the length, width, and height of the major axis are 0.02 mm or more. In one embodiment, the content of lithium (Li) may include 4 to 35 wt% based on 100 wt% of the total weight of the composition for recovering a lithium compound.

[0014] In one embodiment, the composition for recovering lithium compounds may include at least one of LiAlO2, Li5AlO4, LiAl5O8, Li2CO3, LiF, Li3PO4, Li2SiO3, Li4SiO4, and Li2Si2O5. In one embodiment, the composition for recovering lithium compounds may satisfy the following formula 1.

[0015] <Formula 1>

[0016] 1<= ([LiAlO2]+[Li5AlO4]+[LiAl5O8]) / ([LiF]+[Li2CO3]+[Li3PO4]+[Li2SiO3]+[Li4SiO4]+[Li2Si2O5]) <= 10

[0017] ([LiAlO2], [Li5AlO4], [LiAl5O8], [LiF], [Li2CO3], [Li3PO4], [Li2SiO3], [Li4SiO4], [Li2Si2O5] represent the crystal phase ratios of LiAlO2, Li5AlO4, LiAl5O8, LiF, Li2CO3, Li3PO4, Li2SiO3, Li4SiO4, and Li2Si2O5, respectively)

[0018] In one embodiment, the composition for recovering lithium compounds may satisfy the following equation 2.

[0019] <Formula 2>

[0020] 0.1 ≤ I A / I B ≤ 1.5

[0021] (I A is the peak intensity value of 2θ = 21 °± 0.5 ° of LiAlO2 product, and I B refers to the peak intensity value of 2θ = 32.6 °± 0.4 ° of LiAlO2 product)

[0022] In one embodiment, the composition for recovering lithium compounds may satisfy the following equation 3.

[0023] <Formula 3>

[0024] [Al] = 0.745 × [Li] ± 0.3

[0025] ([Al] and [Li] represent the moles of Al and Li in the lithium-containing compound, respectively)

[0026] According to another embodiment of the present invention, a method for processing a battery using a composition for recovering lithium compounds comprises the steps of preparing a battery containing lithium (Li) and aluminum (Al), crushing the battery into battery shreds, and performing a high-temperature heat treatment on the crushed battery shreds, wherein the high-temperature heat treatment step is performed at a temperature range of 600 to 1,500°C, and in the step of preparing the battery, lithium and aluminum in the battery satisfy the following equation 4.

[0027] <Formula 4>

[0028] 0.1 ≤[Li] / [Al]≤ 1.0

[0029] (In the above equation 4, [Li] and [Al] represent the weight ratio (wt%) of lithium and aluminum in the battery)

[0030] In one embodiment, in the step of shredding the battery into battery shreds, the battery shreds may have a structure in which a positive electrode material including a current collector and a negative electrode material including carbon are laminated. In one embodiment, in the laminated structure, the positive electrode material and the negative electrode material may be spaced apart from each other by 0.01 to 5 mm.

[0031] In one embodiment, in the step of crushing the battery into battery shredders, the battery shredders have a tap density of 200 to 1000 kg / m 3 In one embodiment, after the step of high-temperature heat-treating the shredded battery waste, the step of pulverizing a composition containing high-temperature heat-treated lithium may be further included.

[0032] In one embodiment, the step of crushing the battery may be performed to crush the battery fragments to a size of 5 to 50 mm. In one embodiment, after the step of high-temperature heat-treating the crushed battery fragments, the composition containing the high-temperature heat-treated lithium may be recovered by leaching it with an acidic solution having a pH of 1 to 5.

[0033] In one embodiment, in performing the step of crushing the battery, the distribution can be controlled so that the proportion of materials having a size of 0.1 to 100 mm has a proportion of 60% or more within the entire raw material.

[0034] According to one embodiment of the present invention, a composition for recovering lithium compounds has a square shape, thereby providing a lithium-containing composition having an excellent lithium recovery rate.

[0035] According to another embodiment of the present invention, a battery processing method can increase the recovery rate of lithium by controlling the weight ratio of lithium and aluminum in the battery during the step of preparing the battery, thereby producing a lithium-containing composition having a high lithium content.

[0036] FIG. 1 is an SEM photograph of a composition for recovering valuable metals according to one embodiment of the present invention.

[0037] Figure 2 shows the reaction ratio of lithium and aluminum in a composition for recovering lithium compounds.

[0038] FIG. 3 is a photograph of battery shredders for battery processing according to one embodiment of the present invention.

[0039] FIGS. 4 and 5 are photographs showing a laminated structure of a battery shredder according to one embodiment of the present invention.

[0040] Figures 6a and 6b are graphs of XRD peak results of lithium compounds.

[0041] Figure 7 shows the leaching rate in sulfuric acid versus the Si content in the lithium compound.

[0042] Figure 8 is a photograph showing the shape of the reactant according to the size of the raw material of the present invention.

[0043] Figure 9a shows the spherical shape of a nickel alloy, Figure 9b is a photograph showing the shape of a lithium compound, and Figure 9c is a photograph according to the shape of various lithium compounds.

[0044] The terms first, second, and third, etc., are used to describe, but are not limited to, various parts, components, regions, layers, and / or sections. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, a first part, component, region, layer, or section described below may be referred to as a second part, component, region, layer, or section without departing from the scope of the present invention.

[0045] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present invention. As used herein, the singular forms "singular" and "comprising" include plural forms as well, unless the context clearly dictates otherwise. The word "comprising" as used herein specifies a particular feature, region, integer, step, operation, element, and / or component, but does not exclude the presence or addition of other features, regions, integers, steps, operations, elements, and / or components.

[0046] When a part is referred to as being "on" or "over" another part, it can be directly on or over the other part, or there may be other parts intervening. Conversely, when a part is referred to as being "directly on" another part, there are no other parts intervening.

[0047] Additionally, % in this specification means weight % unless otherwise specified.

[0048] Although not defined otherwise, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or overly formal unless otherwise defined.

[0049] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and the present invention is not limited thereto, and the present invention is defined solely by the scope of the claims set forth below.

[0050] FIG. 1 is an SEM photograph of a composition for recovering valuable metals according to one embodiment of the present invention.

[0051] Referring to FIG. 1, a composition for recovering valuable metals according to one embodiment of the present invention comprises a first compound in a core-shell configuration, including a core portion and a shell portion disposed on the core portion, a second compound containing lithium, and carbon. The composition for recovering valuable metals may be recovered from a spent battery as a composition obtained through a battery processing method, as described below.

[0052] The core portion of the first compound may include a valuable metal recovery alloy. The valuable metal of the present invention may refer to a high-value metal component contained in a battery, such as nickel, cobalt, manganese, aluminum, copper, or lithium. The core portion of the composition for recovering valuable metals may be recovered from a cathode component within a spent battery.

[0053] The shell portion within the first compound may be disposed on the core portion and may include a lithium compound. Specifically, when recovering valuable metals from a spent battery, the valuable metals within the spent battery exist in the form of oxides and are reduced by graphite within the negative electrode material through a high-temperature heat treatment process. At this time, the copper current collector may melt and exist in a liquid state, thereby acting to aggregate the reduced valuable metals. The copper current collector and the aluminum current collector may partially perform a reduction reaction with the positive electrode oxide and the remainder may react with lithium, so that a compound in the form of an oxide containing lithium may remain.

[0054] The lithium compound bonded and arranged in the shell portion of the core-shell-shaped material can be separated from the core portion through pulverization, as in the battery processing method described below. The lithium compound bonded and arranged in the shell portion and the second compound containing lithium produced by separating from the core-shell-shaped material in the composition for recovering valuable metals may have the same components and characteristics, and at least one of the lithium compound separated from the shell portion in the first compound and the second compound containing lithium can be defined as the composition for recovering lithium compounds.

[0055] In one embodiment, the composition for recovering a lithium compound may have a prismatic shape. Specifically, the composition for recovering a lithium compound may have a pointed shape in which, when a polygon is drawn using lines parallel to the outside of the composition for recovering a lithium compound, as observed in an SEM image at a magnification of ( ), there is at least one region where the angle between two outer lines is 90° or less.

[0056] The above shape may be formed by controlling the oxygen content to a trace level in a battery processing method and performing heat treatment so that the lithium compound recovery composition is combined with an aluminum current collector and Li-Al-O is covalently bonded. Since the lithium compound recovery composition has a square shape, there is an advantage in that the lithium compound bound to the shell portion is easily decomposed in a subsequent process, thereby increasing the lithium recovery rate.

[0057] In one embodiment, the content of lithium (Li) in the composition for recovering lithium compounds may be 4 to 35 wt%, specifically 4 to 15 wt%, based on 100 wt% of the total.

[0058] By ensuring that the content of Li in the composition for recovering the lithium compound satisfies the above-mentioned range, a composition containing a lithium-containing compound having a high lithium content and an excellent lithium recovery rate can be achieved. If the content of Li exceeds the upper limit of the above-mentioned range, there is a problem in that the lithium recovery rate is reduced due to the generation of a large amount of compounds that are difficult to recover due to water solubility issues as the Li2O content increases, and if the content of Li exceeds the lower limit of the above-mentioned range, there is a problem in that the lithium recovery rate is low and thus has no utility value.

[0059] In one embodiment, the composition for recovering lithium compounds may include at least one of LiAlO2, Li5AlO4, LiAl5O8, Li2CO3, LiF, Li3PO4, Li2SiO3, Li4SiO4, and Li2Si2O5. In one embodiment, the composition for recovering lithium compounds may include lithium aluminum oxide.

[0060] The lithium compound in the composition for recovering the lithium compound may be, for example, lithium oxide. The lithium-aluminum oxide may be implemented in the form of an oxide in which lithium contained in the composition is physically or chemically bonded.

[0061] In one embodiment, the lithium compound in the composition for recovering lithium compounds may include lithium aluminum oxide. Specifically, the content of lithium aluminum oxide may range from 45.0 to 97.0 wt% based on 100 wt% of the composition for recovering lithium compounds. Specifically, the content may range from 45.0 to 80.0 wt%.

[0062] If the content of the lithium aluminum oxide exceeds the upper limit of the aforementioned range, it means that the reaction temperature was processed at too high a temperature, so all the lithium reacted with the aluminum, and there is a possibility that the lithium itself was volatilized and gasified. This has high lithium aluminum properties, but there is a problem in terms of the overall recovery rate. If the content of the lithium aluminum oxide exceeds the lower limit of the aforementioned range, there is a problem that the lithium may not have reacted with the aluminum oxide, or the size of the lithium compound may be small, so there is a problem that carbon or nickel alloy may be mixed inside.

[0063] In one embodiment, Li3PO4 may be included in an amount of 10 wt% or less based on 100 wt% of the entire composition. The Li3PO4 may be included in an amount of 5 wt%, specifically, 3 wt% or less, and more specifically, 0.1 to 0.7 wt%, based on 100 wt% of the entire composition. When the Li3PO4 content satisfies the above-mentioned range, PO is present during acid leaching. 3- The problem of LiOH being generated when removing impurities and leaching behavior according to pH change by anions can be prevented from reducing the Li recovery rate. When the Li3PO4 content satisfies the above-mentioned range, PO is generated during acid leaching. 3- It can prevent the Li recovery rate from decreasing due to problems such as leaching behavior according to pH change by anions and LiOH generation during impurity removal.

[0064] In one embodiment, the composition for recovering lithium compounds may satisfy the following equation 1.

[0065] <Formula 1>

[0066] 1 ≤ ([LiAlO2]+[Li5AlO4]+[LiAl5O8]) / ([LiF]+[Li2CO3]+[Li3PO4]+[Li2SiO3]+[Li4SiO4]+[Li2Si2O5]) ≤ 10

[0067] ([LiAlO2], [Li5AlO4], [LiAl5O8], [LiF], [Li2CO3], [Li3PO4], [Li2SiO3], [Li4SiO4], [Li2Si2O5] represent the crystal phase ratios of LiAlO2, Li5AlO4, LiAl5O8, LiF, Li2CO3, Li3PO4, Li2SiO3, Li4SiO4, and Li2Si2O5, respectively)

[0068] The above equation 1 is a relationship for the crystal phase ratio of lithium-containing compounds in a composition including a lithium-containing compound, which is a reactant produced through the high-temperature reduction reaction described below. The above equation 1 can satisfy a ratio of 1.0 to 10.0, specifically 2.0 to 8.5, and more specifically 2.80 to 7.40.

[0069] By satisfying the above formula 1, the composition containing a lithium-containing compound, which is a composition for recovering lithium compounds of the present invention, has the advantage of improving the lithium yield by promoting the formation of crystal phases of LiAlO2, Li5AlO4 and LiAl5O8. In the case where the content of the above formula 1 is not satisfied, specifically, when the content has a value lower than the content of the above formula 1, there are problems such as a decrease in the lithium yield as LiF is vaporized, a decrease in the acid leaching rate due to an increase in the Si content, and a decrease in the acid leaching rate due to an increase in the PO content during acid leaching. 3- The problem of low Li recovery rate may occur due to problems such as leaching behavior according to pH change by anions and LiOH generation during impurity removal, and in the case of Li2CO3 and LiF, the problem of low Li recovery rate may occur due to the generation of large amounts of compounds that are difficult to recover due to water solubility problems.

[0070] In one embodiment, the composition for recovering lithium compounds may satisfy the following equation 1.

[0071] <Formula 2>

[0072] 0.1 ≤ I A / I B ≤ 1.5

[0073] (In the above equation 2, I Ais the peak intensity value of 2θ = 21 °± 0.5 ° of LiAlO2 product, and I B is the peak intensity value of 2θ = 32.6 °± 0.4 ° of LiAlO2 product)

[0074] The above equation 2 is a relationship for the ratio of peak intensity values ​​at a specific angle of LiAlO2, which is a lithium oxide in a composition for recovering a lithium compound, which is a reactant produced through the high-temperature reduction reaction described below. The above equation 2 can satisfy 0.1 to 1.5, specifically 0.3 to 1.5, and more specifically 0.7 to 1.3.

[0075] The above equation 2 is LiAl7O with high Al2O3 when it exceeds the lower limit of the aforementioned range. 11 There is a problem that the lithium recovery rate is lowered because the phase is excessively generated and, accordingly, the Li leaching rate is lowered. In the above equation 2, if the upper limit of the above range is exceeded, a large amount of Li2O is generated, and as the temperature rises, the lithium evaporates, which causes a problem in that the lithium recovery rate is lowered.

[0076] In one embodiment, LiAlO2 can include XRD peaks of at least one of 20.5 to 21.5°, 29.0 to 29.5°, 31.5 to 32.0°, 32.2 to 33.0°, 60.5 to 61.5°, and 70.0 to 72.0°. Li5AlO4 can include XRD peaks of at least one of 19.5 to 20.2° and 21.6 to 22.2°.

[0077] The LiAl5O8 composition may include at least one of XRD peaks from 15.0 to 17.4°, from 24.2 to 26.1°, from 31.4 to 33.1, from 36.2 to 40.3, from 46.1 to 47.3, from 61.1 to 63.4, and from 66.2 to 68.7. The LiF composition may include at least one of XRD peaks from 37.5 to 40.2°, from 43.9 to 46.5°, and from 64.5 to 66.5°.

[0078] The Li3PO4 composition may include at least one of XRD peaks from 29.2 to 40.1° and from 52 to 77.1°. The Li2SiO3 composition may include at least one of XRD peaks from 17.7 to 20.1°, 26.1 to 29.5°, 32.2 to 36.2, and 37.6 to 39.7. The Li4SiO4 composition may include at least one of XRD peaks from 16.2 to 18.3°, 21.4 to 25.2°, 34.2 to 39.7, and 59.2 to 63.4.

[0079] The Li2Si2O5 composition may include at least one of XRD peaks from 16.2 to 18.3°, from 21.4 to 25.2°, from 34.2 to 39.7°, and from 59.2 to 63.4°. The Li2CO3 composition may include at least one of XRD peaks from 24.0 to 26.0°, from 27.0 to 29.0°, from 34.0 to 36.0°, and from 37.0 to 39.0°.

[0080]

[0081] In one embodiment, the composition for recovering lithium compounds may satisfy the following equation 3.

[0082] <Formula 3>

[0083] [Al] = 0.745 × [Li] ± 0.3

[0084] ([Al] and [Li] represent moles of Al and Li, respectively)

[0085] Through the above equation 3, it was confirmed that elements with strong oxidizing power at high temperatures, such as Li and Al, generate reaction products such as LiAlO2, Li5AlO4, and LiAl5O8 that are stable at high temperatures. The equation 3 can be included in the range of [Al] = 0.745 × [Li] + 0.3 as an upper limit value and [Al] = 0.745 × [Li] - 0.3 as a lower limit value. By not satisfying the equation 3, there is a problem that the generation of lithium aluminum oxide with strong oxidizing power at high temperatures is reduced.

[0086] Figure 2 shows the reaction ratio of lithium and aluminum in a composition for recovering lithium compounds.

[0087] Referring to Fig. 2, it can be confirmed that the mole numbers of lithium and aluminum satisfy the range of the above equation 3.

[0088] According to another embodiment of the present invention, a battery processing method includes the steps of preparing a battery, crushing the battery into battery shreds, and performing a high-temperature heat treatment on the crushed battery shreds.

[0089] In the step of preparing the battery, the battery may be a method for processing various types of batteries containing lithium ions, and the battery may be, for example, a lithium secondary battery separated from an automobile, a secondary battery separated from an electronic device such as a mobile phone, a camera, or a laptop, and specifically, a lithium secondary battery. More specifically, the battery utilizes a waste battery, and thus has the advantage of being environmentally friendly.

[0090] In one embodiment, during the battery preparation step, the battery may include lithium (Li) and aluminum (Al). By coexisting lithium and aluminum within the battery, the lithium and aluminum may be physically and / or chemically bonded in the resulting product after battery processing.

[0091] In one embodiment, the step of preparing the battery may include the step of freezing the battery. The step of freezing the battery is a step for stabilizing the electrolyte within the battery, and has the advantage of reducing the risk of fire occurring during the battery crushing step described below.

[0092] The step of freezing the battery is performed at a temperature sufficient to freeze the electrolyte contained within the battery. Specifically, the step of freezing may be performed at a temperature range of, for example, -150 to -20°C. More specifically, the temperature range may be -150 to -50°C, and even more specifically, -80 to -60°C.

[0093] When the battery is frozen in the above temperature range, the voltage remaining slightly inside the battery, for example, about 2 V to 3 V, is lowered to close to 0 V, and even if a short circuit occurs in which the positive and negative electrodes are in direct contact, no battery reaction occurs, so the battery temperature does not increase, and gas generation and combustion of the electrolyte do not occur. In addition, since the electrolyte is in a frozen state or in a state in which vaporization is suppressed, the mobility of lithium ions is very low, so that the conduction characteristics according to the movement of lithium ions can be significantly reduced, and since vaporization of the electrolyte does not occur, flammable gases such as ethylene, propylene, and hydrogen can not be generated.

[0094] If the above freezing process is outside the above temperature range, for example, if it cools to a temperature higher than -60℃, the voltage remaining inside the battery will not be lowered to 0 V, so a battery reaction due to a short circuit may occur, and the electrolyte will not be completely frozen, which is not appropriate. In addition, if it is cooled to -150℃, the electrolyte is sufficiently frozen, and the voltage inside the battery will also be lowered to 0 V, so there is no need to lower the temperature below this. In this way, the battery processing method has the advantage of preventing the risk of fire that may occur during the battery crushing process by including a freezing step before crushing a battery such as a lithium secondary battery.

[0095] In one embodiment, the step of preparing the battery may be such that the weight of lithium and aluminum in the battery satisfies the following equation 4.

[0096] <Formula 4>

[0097] 0.1 ≤ [Li] / [Al] ≤ 1.0

[0098] (In the above equation 4, [Li] and [Al] represent the weight ratio (wt%) of lithium and aluminum in the battery)

[0099]

[0100] The above equation 4 may be an indicator of the raw material state in the battery preparation stage. The above equation 3 may satisfy 0.1 to 1.0, specifically, 0.2 to 0.6.

[0101] The above equation 4 has a problem in that unreacted aluminum is generated when the upper limit of the above-mentioned range is exceeded. The above equation 4 has a problem in that unreacted lithium is generated when the lower limit of the above-mentioned range is exceeded.

[0102] The step of shredding the battery may refer to a process of applying shock or pressure to the battery so that a portion of the battery detaches from the battery. In one embodiment, the step of shredding the battery may refer to a process of crushing the battery, a process of cutting the battery, a process of compressing the battery, or a combination thereof. Specifically, the step of shredding may include any process that destroys the battery to obtain small-sized shredded materials.

[0103] In one embodiment, the step of crushing the battery may include any process of compressing the prepared battery or applying an external force, such as a shear force or tensile force, to destroy the battery. The step of crushing the battery may be performed, for example, using a crusher.

[0104] In one embodiment, the step of crushing the battery may be performed at least once. Specifically, the step of crushing may be performed at least once, either continuously or discontinuously.

[0105] In one embodiment, the step of crushing the battery may crush the battery to a size of 5 to 50 mm. Specifically, the step of crushing the battery may crush the battery to a size of 10 to 30 mm. When the battery is crushed within the above range, the size of the reactant recovered through the thermal reduction process is formed to be greater than 0.1 mm, thereby facilitating the separation of the magnetic material, the valuable metal recovery alloy, the lithium compound, and the carbon.

[0106] If the step of crushing the battery is performed so as to produce crushed materials larger than the upper limit of the above-mentioned range, there is a problem that the size of lithium aluminate increases or does not react in the center. If the step of crushing the battery is performed so as to produce crushed materials larger than the lower limit of the above-mentioned range, there is a problem that the size of the raw material battery crushed materials is excessively small and the size of the reactant produced from the battery crushed materials is similar to the size of carbon, making it difficult to separate from the carbon, thereby lowering the lithium recovery rate.

[0107] In one embodiment, the distribution of the raw material can be controlled so that the proportion of materials having a size of 0.1 to 100 mm according to the step of crushing the battery has a proportion of 60% or more within the entire raw material. If the distribution of the raw material is excessively smaller than the aforementioned range, there is a problem that the size of the raw material after the reaction becomes excessively small, making it difficult to separate non-magnetic carbon and lithium compounds. If the distribution of the raw material is excessively larger than the aforementioned range, there is a problem that many pores are generated in the raw material, which causes a problem that the heat transfer characteristics are lowered, and an excessive high-temperature maintenance time is required to process the reactants, resulting in a problem that the reaction efficiency is lowered.

[0108] In one embodiment, the step of crushing the battery can be performed under conditions of supplying an inert gas, carbon dioxide, nitrogen, water, or a combination thereof, or under vacuum conditions of 100 torr or less. For example, when the process of freezing the battery is performed by cooling it in a temperature range of -60 to -20°C, when performed under the above-described conditions, the supply of oxygen can be suppressed, preventing the electrolyte from reacting with oxygen, thereby preventing an explosion caused by this, and the vaporization of the electrolyte can be suppressed, thereby preventing the generation of flammable gases such as ethylene, propylene, or hydrogen.

[0109] In one embodiment, in the step of shredding a battery, the battery shreds may have a structure in which a positive electrode material including a current collector and a negative electrode material including carbon are laminated. Specifically, the battery shreds may have a multiple-layer structure in which a positive electrode material, a separator, and a negative electrode material are sequentially laminated.

[0110] In one embodiment, the positive electrode material and the negative electrode material in the laminated structure can be spaced apart from each other by a distance of 0.01 to 5 mm. Specifically, the space can be spaced apart from each other by a distance of 0.1 to 3 mm.

[0111] The above gap satisfies the aforementioned range, which has the advantage of improving reaction efficiency. If the gap exceeds the upper limit of the aforementioned range, there is a problem in which aluminum and lithium do not react and become lithium carbon or other compounds or volatilize.

[0112] In one embodiment, the step of crushing the battery may be performed so that the maximum size of the battery shreds is 100 mm or less. Specifically, the size of the battery shreds may be performed so that the size of the battery shreds is 50 mm or less. If the maximum size of the battery shreds is 100 mm or more, the temperature of the heat generated due to instability as the battery shreds are crushed may rise to a temperature range of 120°C, which is the average vaporization temperature of the electrolyte, which may cause safety issues such as fire.

[0113] In one embodiment, in the step of crushing the battery into battery shredders, the battery shredders have a tap density of 200 to 1,000 kg / m 3 It can be. Specifically, the tap density is 300 to 700 kg / m 3 It could be.

[0114] If the tap density exceeds the upper limit of the aforementioned range, the content of fine particles of 0.1 mm or less in the raw material increases, making it difficult to separate carbon and lithium compounds from the non-magnetic material of the final product. If the tap density exceeds the lower limit of the aforementioned range, the reaction rate slows down due to the presence of many pores in the reaction state.

[0115] The step of high-temperature heat treatment of the shredded battery scrap may include placing the shredded battery scrap in a heating furnace capable of raising the temperature to a temperature higher than the melting point of the shredded battery. The shredded battery scrap may include, for example, valuable metals such as Ni, Co, Mn, and Li. The high-temperature heat treatment may involve heat treatment conditions that perform a high-temperature reduction reaction without melting the battery.

[0116] In one embodiment, the step of high-temperature heat treatment of the battery shredded material may be performed in a gas atmosphere containing at least one of an inert gas, carbon dioxide, carbon monoxide, hydrocarbon gas, and oxygen. The inert gas may, for example, contain at least one of argon and nitrogen. By performing a reduction reaction of the shredded material in the gas atmosphere, the recovery rate of valuable metal elements contained in the battery shredded material can be increased.

[0117] In one embodiment, the step of high-temperature heat treating the Ni, Co, Mn, and Li-containing battery waste may be performed in a gas atmosphere comprising at least one of an inert gas, carbon dioxide, carbon monoxide, and a hydrocarbon gas; and oxygen. In one embodiment, the gas atmosphere may be performed in a gas atmosphere in which the oxygen concentration ranges from 0.1 to 2.0 vol%. Specifically, the gas atmosphere may be performed in a gas atmosphere in which the oxygen concentration ranges from 0.4 to 1.2 vol%.

[0118] When the oxygen concentration exceeds the upper limit of the above-mentioned range, there is a problem that the reaction of Li2O + C + O2(g) = Li2CO3 is promoted as the oxygen concentration increases, but at the same time, LiAlO2 and Li5AlO4 decrease. Specifically, when the oxygen concentration exceeds the upper limit of the above-mentioned range, there is a problem that carbon dioxide is excessively formed during the reduction reaction and is lost as gas together with lithium, or the production of Li2CO3(s) increases excessively, making recovery by acid leaching difficult. When the oxygen concentration exceeds the lower limit of the above-mentioned range, there is a problem that the lithium recovery rate decreases.

[0119] In one embodiment, the step of high-temperature heat treatment of the battery shreds may be performed in a range of 600 to 1,500°C. Specifically, the step of high-temperature heat treatment may be performed in a range of 900 to 1,500°C, more specifically in a range of 1,100 to 1,500°C, and even more specifically in a range of 1,300 to 1,500°C. In the step of high-temperature heat treatment of the battery shreds, as the temperature increases, LiAlO2(s)+2Li2CO3(s) = Li5AlO4+2CO2(g) reaction is used to generate Li5AlO4, but the LiF(g) vaporization reaction is promoted, so that when performed in the above-described range, the yield of lithium can be improved.

[0120] Beyond the upper limit of the above range, there is a problem of lithium loss due to lithium vaporization. Specifically, beyond the upper limit of the above range, there is a problem of lithium recovery rate being reduced due to lithium loss as the LiF(g) vaporization reaction is excessively promoted.

[0121] If the lower limit of the above range is exceeded, the sintering and reduction of the alloy elements do not proceed smoothly, and a stabilized lithium-containing compound is not formed, which makes it difficult to recover the stabilized compound when recovering the lithium compound in the future. Specifically, if the lower limit of the above range is exceeded, MnO among the Li-containing Ni, Co, and Mn oxides in the positive electrode material is not dissociated, and MnAl2O4 is generated due to the reaction MnO(s)+2Al(s)+3 / 2O2=MnAl2O4(s), which reduces the lithium concentration in the lithium compound, resulting in a problem of a lower lithium recovery rate.

[0122] In one embodiment, after the step of high-temperature heat-treating the shredded battery waste, a step of pulverizing a composition containing high-temperature heat-treated lithium may be further included. Specifically, the step of pulverizing a composition containing high-temperature heat-treated lithium may be a step of physically separating a core portion containing a valuable metal and a lithium-containing compound from the composition containing lithium using an external force.

[0123] By including a step of pulverizing a composition containing lithium subjected to the above-described high-temperature heat treatment, the core portion containing the valuable metal and the shell portion composed of a compound containing lithium can be separated, thereby further recovering lithium contained in the shell portion. By further recovering lithium from the shell portion, the recovery rate of the lithium ultimately recovered can be increased.

[0124] In one embodiment, a battery processing method may include, after a high-temperature heat treatment step, a step of obtaining a composition comprising a lithium compound remaining after separating nickel or iron-containing alloys through magnetic separation. Specifically, the battery processing method may include, after the high-temperature heat treatment step, a step of magnetically separating the heat-treated resultant product using a magnetic strength of 1000 G or greater. More specifically, the magnetic strength may be 1500 G or greater.

[0125] Specifically, after the high-temperature heat treatment step, a composition including a lithium compound and a powder including a nickel alloy, for example, a black powder, may be included. By separating the nickel or iron-containing alloy included in the black powder through magnetic separation, a composition including a lithium compound can be separated and obtained.

[0126] In one embodiment, a battery processing method may include, after a high-temperature heat treatment step, a step of particle-separating lithium compounds having a maximum long-axis length of 20 μm or more among the heat-treated resultant particles. Specifically, lithium compounds having a maximum long-axis length of 20 μm or more among the length, width, and height of the heat-treated resultant particles may be separated through particle-separation. By performing particle-separation, the lithium compound may be separated through a simple process, thereby increasing the lithium recovery rate.

[0127] In one embodiment, the battery processing method may include, after the high-temperature heat treatment step, a step of separating lithium compounds having a specific gravity less than 3 based on a bulk specific gravity of 3 from the heat-treated resultant. By separating the lithium compounds easily through the specific gravity separation method, the recovery rate of lithium can be increased.

[0128] In one embodiment, the battery processing method may further comprise a step of recovering lithium by leaching the composition comprising the lithium compound with an acidic solution. The acidic solution may have a pH of 4 or less.

[0129] When the pH is 4 or higher, there is a problem in that the stabilized lithium-containing compound cannot secure the target precipitation rate. The acidic solution may be, for example, a solution such as sulfuric acid. Specifically, the composition including the lithium compound may be leached with the acidic solution to dissolve metals such as aluminum in the lithium compound, thereby recovering lithium.

[0130] In one embodiment, the leaching rate of the composition comprising a lithium-containing compound in sulfuric acid may be greater than or equal to 95%. Specifically, the leaching rate of the composition comprising a lithium-containing compound in sulfuric acid may be greater than or equal to 96%. By increasing the leaching rate of the composition comprising the lithium-containing compound, there is an advantage in that the lithium recovery rate can be maximized.

[0131]

[0132] Hereinafter, preferred embodiments and comparative examples of the present invention are described. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

[0133] <Experimental Example> - Control of Waste Battery Conditions

[0134] FIG. 3 is a photograph of battery shredders for battery processing according to one embodiment of the present invention.

[0135] Referring to Figure 3, battery shredders can be shredded to a maximum length and width of 100 mm or less through a shredding process. Specifically, the optimal size for battery shredders is 10 to 40 mm in maximum length and width. This is to prevent the risk of fire during battery shredding.

[0136] FIGS. 4 and 5 are photographs showing a laminated structure of a battery shredder according to one embodiment of the present invention.

[0137] Referring to FIGS. 4 and 5, when the reaction distance between the positive electrode current collector and the negative electrode current collector is less than 10 mm, when the battery shreds are heat-treated and reduced, a composition can be obtained in which lithium reacts with aluminum and a lithium compound is bonded to the surface of the precious metal recovery alloy. Specifically, when the reaction distance is greater than 10 mm, there is a problem in that the lithium in the aluminum and the positive electrode material, electrolyte, and negative electrode material does not react with the aluminum but volatilizes, thereby lowering the purity of the lithium reaction with the aluminum.

[0138]

[0139] Experimental Example 1

[0140] Prepare a scrap material from a spent electric vehicle battery, which includes a positive electrode containing lithium ions, a negative electrode made of graphite, an aluminum current collector, a separator, an electrolyte, and a copper current collector. The spent battery is shredded using a shredding device so that the longest length or width is less than 100 mm.

[0141] The reaction distance between the aluminum current collector and the copper current collector in the spent battery was controlled to be shorter than 1 mm, and the ratio of Li (wt%) / Al (wt%) in the spent battery was controlled to 1.3, and then shredding was performed. The shredded battery shreds were heated to 1250°C to obtain a composition for recovering valuable metals, and then the content of a compound including lithium in the composition for recovering valuable metals was measured.

[0142]

[0143] Experimental Example 2

[0144] A composition for recovering valuable metals was obtained by conducting an experiment in the same manner as Experimental Example 1, except that the reaction distance between the aluminum current collector and the copper current collector was 3 mm and the ratio of Li (wt%) / Al (wt%) in the spent battery was controlled to 1.2.

[0145]

[0146] Experimental Example 3

[0147] A composition for recovering valuable metals was obtained by conducting an experiment in the same manner as Experimental Example 1, except that the reaction distance between the aluminum current collector and the copper current collector was 5 mm and the ratio of Li (wt%) / Al (wt%) in the spent battery was controlled to 0.2.

[0148]

[0149] Experimental Example 4

[0150] A composition for recovering valuable metals was obtained by conducting an experiment in the same manner as Experimental Example 1, except that the reaction distance between the aluminum current collector and the copper current collector was 10 mm and the ratio of Li (wt%) / Al (wt%) in the spent battery was controlled to 0.03.

[0151]

[0152] Experimental Example 5

[0153] A composition for recovering valuable metals was obtained by conducting an experiment in the same manner as Experimental Example 1, except that the reaction distance between the aluminum current collector and the copper current collector was 15 mm and the ratio of Li (wt%) / Al (wt%) in the spent battery was controlled to 0.01.

[0154] Figures 6a and 6b are graphs of XRD peak results of lithium compounds.

[0155] The reaction distance in Table 1 below is the distance measured between the aluminum current collector and the copper current collector.

[0156] Li(wt%) / Al(wt%) was measured using a confocal test device, and the analysis was measured using XPS (X-ray photoelectron spectroscopy).

[0157] Spent Battery Conditions Lithium Aluminum Oxide [wt%] Lithium Carbonate [wt%] LiF [wt%] Others [wt%] Reaction Distance [mm] Li (wt%) / Al (wt%) LiAlO2 Li2CO3 LiF Graphite, Cu, Experimental Example 1 <11.3 36.4 4.0 12.5 47.1 Experimental Example 2 31.2 36.14 0 12.15 1.6 Experimental Example 3 5 0.2 2 0.36 2 12.9 6 0.6 Experimental Example 4 10 0.0 3 4.1 12.1 14.5 6 9.3 Experimental Example 5 15 0.0 12.6 15.2 15.5 6 6.7

[0158] Looking at Table 1 and Figures 6a and 6b above, the ratio of lithium aluminum oxide gradually decreases when aluminum is low. At this time, as aluminum decreases, the ratio of reaction with fluorine increases slightly, but the ratio of lithium reacting with fluorine was limited to a maximum of 15.5% because the amount of fluorine is difficult to control. It seems that the weight ratio of lithium carbonate will also increase if maintained at a low temperature for a long time when the amount of aluminum is low, but in this experiment, since it was conducted in an oxygen atmosphere of less than 0.1% at around 1,250 degrees, the weight ratio of lithium carbonate did not continue to increase. It was determined that this occurred because the remaining lithium was vaporized. Specifically, as in the example, when the reaction distance between the positive electrode collector and the negative electrode and collector was less than 10 mm, the purity of lithium reaction with aluminum was high, and it was confirmed that the content of lithium aluminum oxide was high. In Table 1 above, it was determined that the XRD peak value of less than 100% was due to some lithium being vaporized or changed into a form such as lithium phosphate or lithium fluoride.

[0159] Figure 7 shows the leaching rate in sulfuric acid versus the Si content in the lithium compound.

[0160] Looking at Figure 7, it shows the leaching rate of Li in sulfuric acid when a lithium compound is leached in 1M sulfuric acid at 50°C for 2 hours. As can be seen in Figure 7, when Si in the lithium compound is limited to 12% or less, it can be confirmed that leaching is easy even without heating to 900°C or higher.

[0161]

[0162] <Reactant form according to raw material size and heat treatment conditions control>

[0163] Figure 8 is a photograph showing the shape of the reactant according to the size of the raw material of the present invention.

[0164] Referring to Figure 8, the form of the reactant formed from the raw material having a size of 0.1 mm or less and the form of the reactant formed from the raw material having a size of 10 to 30 mm are shown. The form of the raw material having a size of 0.1 mm or less is also 30 ㎛ or less for the reactant, and since the size of the carbon is 30 ㎛ or less, in the case of the nickel alloy, cobalt is included and magnetic separation is possible, but the lithium compound is a non-magnetic substance and has a similar size to the carbon, making separation difficult.

[0165] When the size of the above raw material is 10 to 30 mm, the reactant may also be 0.1 mm or larger. Accordingly, the nickel alloy can be magnetically separated, and the non-magnetic lithium compound and carbon can be separated by particle size.

[0166] At this time, it was confirmed that the shape of the reactant was a spherical shape for the nickel alloy containing nickel, but a square shape for the lithium compound.

[0167] Figure 9a shows the spherical shape of a nickel alloy, and Figure 9b is a photograph showing the shape of a lithium compound.

[0168] Referring to Fig. 9a, in the case of a nickel alloy, it was confirmed that the shape of a circle is such that when the angle of two lines passing through the center is within 90°, the angle of the tangent of the two lines is greater than 90°.

[0169] The components of the nickel alloy and lithium compound can be confirmed in Fig. 9a. Referring to Fig. 9b, the lithium compound was confirmed to have a polygonal shape. Specifically, when a polygon is drawn using lines parallel to the outside, the lithium compound exhibits a pointed shape with at least one region where the two outer lines intersect at an angle of 90° or less.

[0170] In this reaction form, when the oxygen content in the reaction state is controlled to 5% or less, specifically 1% or less, carbon in the negative electrode material is maintained at more than 10% of the total weight, and in the case of nickel alloy, carbon maintains a circular shape due to very low wettability, but the lithium compound shows a covalent bond form of Li-Al-O when bonded with the aluminum current collector.

[0171] This shape was confirmed to be a polygonal shape overall of the lithium compound due to the brittle nature of the oxide system when it is broken or separated by external force, thermal shock during cooling after reaction, or phase change. Specifically, it was confirmed that the lithium compound has an internal angle of 90° or less within the polygon.

[0172] Figure 9c shows the shapes of various types of lithium compounds, and also includes a method for measuring the angles.

[0173]

[0174] 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 following claims also fall within the scope of the present invention.

Claims

1. A composition comprising a lithium compound recovered from a waste battery, A composition for recovering lithium compounds having a square shape.

2. In paragraph 1, From the SEM image, when a polygon was drawn using lines parallel to the outside of the lithium compound recovery composition, A composition for recovering a lithium compound, comprising a lithium compound having at least one angle where two outlines touch each other of less than 90°.

3. In paragraph 1, A composition for recovering lithium compounds having a length, width, and height of a major axis of 0.02 mm or more.

4. In paragraph 1, A composition for recovering a lithium compound, wherein the content of lithium (Li) is 4 to 35 wt% based on 100 wt% of the entire composition for recovering a lithium compound.

5. In paragraph 1, A composition for recovering lithium compounds comprising at least one of LiAlO2, Li5AlO4, LiAl5O8, Li2CO3, LiF, Li3PO4, Li2SiO3, Li4SiO4, and Li2Si2O5.

6. In paragraph 1, A composition for recovering a lithium compound satisfying the following formula 1. <Formula 1> 1 ≤ ([LiAlO2]+[Li5AlO4]+[LiAl5O8]) / ([LiF]+[Li2CO3]+[Li3PO4]+[Li2SiO3]+[Li4SiO4]+[Li2Si2O5]) ≤ 10 ([LiAlO2], [Li5AlO4], [LiAl5O8], [LiF], [Li2CO3], [Li3PO4], [Li2SiO3], [Li4SiO4], [Li2Si2O5] represent the crystal phase ratios of LiAlO2, Li5AlO4, LiAl5O8, LiF, Li2CO3, Li3PO4, Li2SiO3, Li4SiO4, and Li2Si2O5, respectively.) 7. In paragraph 1, A composition for recovering a lithium compound satisfying the following equation 2. <Formula 2> 0.1 ≤ I A / I B ≤ 1.5 (I A is the peak intensity value of 2θ = 21 °± 0.5 ° of the LiAlO2 product, and I B refers to the peak intensity value of 2θ = 32.6 °± 0.4 ° of LiAlO2 product) 8. In paragraph 1, A composition for recovering a lithium compound satisfying the following formula 3. <Formula 3> [Al] = 0.745 × [Li] ± 0.3 ([Al] and [Li] represent the moles of Al and Li in the lithium-containing compound, respectively) 9. Step of preparing a battery containing lithium (Li) and aluminum (Al); A step of crushing the above battery into battery waste; and A step of performing high-temperature heat treatment on the shredded battery waste; The above high temperature heat treatment step includes a heat treatment step in a temperature range of 600 to 1,500 ℃, In the step of preparing the battery, the lithium and aluminum in the battery include a battery processing step satisfying the following equation 4, <Formula 4> 0.1 ≤[Li] / [Al]≤ 1.0 (In the above equation 4, [Li] and [Al] represent the weight ratio (wt%) of lithium and aluminum in the battery) A method of separating materials produced through the above heat treatment by using magnetism, specific gravity, size separation, etc.

10. In paragraph 9, In the step of crushing the above battery into battery waste, The above battery shredder is a method for processing a battery having a structure in which a positive electrode material including a current collector and a negative electrode material including carbon are laminated.

11. In Article 10, A battery processing method wherein, in the above laminated structure, the positive electrode material and the negative electrode material maintain a gap of 0.01 to 5 mm.

12. In paragraph 9, In the step of crushing the above battery into battery waste, The above battery shredder has a tap density of 200 to 1000 kg / m. 3 How to dispose of a battery.

13. In paragraph 9, After the step of high-temperature heat treatment of the above-mentioned shredded battery waste, A battery processing method further comprising the step of pulverizing a composition containing high-temperature heat-treated lithium.

14. In paragraph 9, The step of crushing the above battery is a battery processing method in which the battery is crushed to a size of 5 to 50 mm.

15. In paragraph 9, After the step of high-temperature heat treatment of the above-mentioned shredded battery waste, A battery processing method comprising the step of recovering a composition containing high-temperature heat-treated lithium by leaching it with an acidic solution having a pH of 1 to 5.

16. In paragraph 9, In performing the step of crushing the above battery, A battery processing method comprising a step of controlling distribution so that a proportion of a material having a size of 0.1 to 100 mm has a proportion of 60% or more within the entire raw material.

17. In paragraph 9, A battery processing method comprising, after the above high-temperature heat treatment step, a step of magnetically separating the heat-treated resultant at a magnetic strength of 1000 G or higher.

18. In paragraph 9, A battery processing method comprising, after a high-temperature heat treatment step, a step of particle-separating a lithium compound having a maximum value of a major axis length of 20 ㎛ or more among the heat-treated results.

19. In paragraph 9, A battery processing method comprising, after a high-temperature heat treatment step, a step of separating lithium compounds having a specific gravity less than 3 based on a bulk specific gravity of 3 from the heat-treated resultant.

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