Method for treating waste battery

Abstract

The present invention relates to a method for treating a waste battery, the method comprising a step for heat-treating a crushed product of the waste battery in an atmosphere that contains oxygen (O2), and satisfying expression 1. <Expression 1> 0.40 ≤ [A] × [B] ≤ 1.50 (In expression 1, [A] represents the vol% of oxygen (O2) in the heat treatment atmosphere in the heat treatment step, and [B] represents the molar ratio (CO / CO2) of carbon monoxide (CO) to carbon dioxide (CO2) in exhaust gas generated from the heat treatment step.

Description

Disposal method for waste batteries

[0001] The present invention relates to waste battery recycling and to a method for processing waste batteries.

[0002] The present invention claims priority based on Korean Patent Application No. 10-2024-0187750 filed on December 16, 2024, the entire contents of said application incorporated herein by reference.

[0003] Battery demand is rapidly increasing as they are widely used not only in electronic devices such as smartphones and mobile devices but also in electric vehicles. The demand for these batteries is expected to rise further as the demand for electric vehicles increases as the next-generation mode of transportation.

[0004] Since the aforementioned electric vehicle requires a battery with a large electrical capacity, it is installed and used in the vehicle in units of multiple battery cells, modules composed of multiple battery cells, and packs composed of multiple modules. As the usage of the electric vehicle increases rapidly, the amount of waste generated from batteries used in the electric vehicle is also increasing.

[0005] Recently, the issue of disposing of lithium-ion batteries, such as waste electric vehicle batteries, has emerged globally. These lithium-ion batteries pose fire hazards due to organic solvents and contain explosive substances as well as heavy metals such as Ni, Co, Mn, and Fe. Among these, Ni, Co, Mn, and Li are valuable metals with scarcity and utility value; therefore, the recovery and recycling processes following the disposal of these lithium-ion batteries have become critical issues.

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

[0007] Research is being conducted on various methods, such as dry and wet recycling methods, to recover these valuable metals. In the case of the dry recycling method mentioned above, research is actively being conducted on an oxidative refining method to efficiently recover metal components. This method involves melting the battery at a high temperature to chemically decompose the metal oxide structure degraded during the battery charging and discharging process, selecting an atmosphere with an appropriate oxygen partial pressure, and oxidizing components other than the target metal to recover the target metal in the form of a molten metal.

[0008] However, components produced through dry recycling methods such as the above-mentioned oxidation refining method have clear limitations in satisfying the purity required for battery grade, so in most cases, it is necessary to increase the purity of the material obtained through dry recycling methods through a wet refining process.

[0009] When utilizing the oxidative refining method among dry methods for waste battery recycling, the graphite derived from the negative electrode active material is completely burned and eliminated. This allows metal droplets to combine to form a molten metal, which is advantageous for operating the entire molten metal. However, from the perspective of carbon emission reduction, which has emerged recently following the Paris Agreement, the graphite removed by combustion is entirely emitted in the form of carbon dioxide. Consequently, this may act as a factor weakening price competitiveness in the process, such as carbon taxes, when entering markets like Europe in the future.

[0010] Furthermore, in addition to the disadvantage of releasing large amounts of carbon dioxide, the dry-oxidation refining method for spent batteries has the drawback that, among valuable metals, metals such as Li and Mn—excluding Ni and Co—are mostly oxidized to form Li-Mn-Al-O slag, or metal elements such as Li, which have a relatively high vapor pressure, may be lost through vaporization.

[0011] Therefore, from the perspective of reducing carbon dioxide emissions, it is necessary to design a process capable of recovering valuable metals under conditions where graphite within spent batteries is not burned as much as possible.

[0012] The technical problem that the present invention aims to solve is to provide a method for treating waste batteries that can reduce carbon dioxide emissions during the heat treatment process of waste batteries.

[0013] A method for treating waste batteries according to one embodiment of the present invention relates to a method for treating waste batteries by heat treating the waste batteries, and includes the step of heat treating the crushed waste batteries in an atmosphere containing oxygen (O2), and can satisfy the following Equation 1.

[0014] <Equation 1>

[0015] 0.40 ≤ [A] × [B] ≤ 1.50

[0016] (In Equation 1 above, [A] represents the vol% of oxygen (O2) in the heat treatment atmosphere during the heat treatment step, and [B] represents the molar ratio (CO / CO2) of carbon monoxide (CO) to carbon dioxide (CO2) in the flue gas generated from the heat treatment step.)

[0017] The molar ratio (CO / CO2) of carbon monoxide (CO) to carbon dioxide (CO2) in the flue gas generated from the step of heat-treating the waste battery crushed material may be 0.40 to 1.20. In one embodiment, in the step of heat-treating the waste battery crushed material in an atmosphere containing oxygen (O2), the oxygen content may be 6 vol% or less based on 100 vol% of the total volume of the reduction furnace.

[0018] In one embodiment, the step of heat-treating the waste battery crushed material in an atmosphere containing oxygen (O2) may be performed at a temperature above which oxides containing valuable metals begin to be reduced. In one embodiment, the method may include the step of discharging the exhaust gas generated from the step of heat-treating the waste battery crushed material to the outside of the furnace where the heat treatment is performed.

[0019] In one embodiment, the exhaust gas may be discharged to the outside under negative pressure conditions of 0 to -20 kPa. In one embodiment, prior to the step of heat-treating the shredded waste battery, the step of shredding the waste battery may be included.

[0020] In one embodiment, the recovery rate of graphite in the resulting product after the step of discharging the exhaust gas outside the furnace where heat treatment is performed may be 85% or more. In one embodiment, the discharged exhaust gas may further include a step of being recirculated to the heat treatment step.

[0021] In one embodiment, the method includes a step of detecting the exhaust gas, and the step of detecting the exhaust gas can determine the operating state of a portion of the gas generated from the step of heat-treating the waste battery crushed material using at least one of gas chromatography, quadrupole mass spectrometry, and non-dispersive infrared absorption method.

[0022] In one embodiment, the heat treatment step may be performed in a range of 1,100 to 1,500 ℃. In one embodiment, the heat treatment step may be performed at an oxygen partial pressure above which the lithium oxide in the battery crushed material is reduced.

[0023] In one embodiment, the oxygen (O2) content in the heat treatment atmosphere during the heat treatment step may be 6.0 vol% or less based on 100 vol% of the total volume of the reduction furnace. In one embodiment, the oxygen (O2) content in the heat treatment atmosphere during the heat treatment step may be 2.1 vol% or less based on 100 vol% of the total volume of the reduction furnace.

[0024] In one embodiment, the molar ratio (CO / CO2) of carbon monoxide (CO) to carbon dioxide (CO2) in the exhaust gas discharged from the heat treatment step may be 0.40 to 1.20. In one embodiment, the step of crushing the waste battery may be performed so that the size of the crushed battery is 100 mm or less.

[0025] According to one embodiment of the present invention, a method for treating waste batteries can reduce the emission of carbon dioxide (CO) during the battery treatment process by controlling the oxygen content to generate carbon monoxide (CO) and reducing the emission of carbon dioxide during the battery treatment process. Furthermore, the carbon monoxide generated by the method for treating waste batteries according to the present invention can be used not only for the reduction of active materials within the waste batteries but can also be recovered separately and used as a substance such as a reducing agent in a heat source or other processes.

[0026] Figure 1 shows the CO / CO2 molar ratio according to the oxygen content of an embodiment of the present invention.

[0027] Terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited thereto. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without departing from the scope of the present invention.

[0028] The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. As used in the specification, the meaning of "comprising" specifies certain characteristics, areas, integers, steps, actions, elements, and / or components, and does not exclude the presence or addition of other characteristics, areas, integers, steps, actions, elements, and / or components.

[0029] When it is stated that one part is "on" or "on" another part, it may be directly on or on the other part, or another part may be involved in between. In contrast, when it is stated that one part is "directly on" another part, no other part is interposed in between.

[0030] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined.

[0031] A method for treating waste batteries according to one embodiment of the present invention includes the step of heat-treating crushed waste batteries in an atmosphere containing oxygen (O2). Specifically, the method for treating waste batteries may relate to a battery treatment method that involves a high-temperature heat treatment process for dry smelting of the waste batteries. More specifically, the method for treating waste batteries according to the present invention may generate carbon monoxide and reduce the emission of carbon dioxide by controlling the oxygen content during the heat treatment process.

[0032] The above-mentioned waste battery shredder may be prepared by shredding a material that serves as the base material for the battery shredder, or the shredding may refer to the material itself. The base material of the above-mentioned battery shredder may include waste batteries such as end-of-life batteries, positive electrode materials such as scrap, jelly rolls, and slurries constituting the upper-stage waste battery, defective products generated during the manufacturing process, residues within the manufacturing process, and generated debris. Specifically, the above-mentioned waste battery shredder refers to shredded waste battery components such as packs, modules, and cells derived from waste batteries, and may be a pre-treated material from which components such as battery casings and bolts, other than positive and negative electrode materials, have been removed.

[0033] In one embodiment, the waste battery crushed material may include a step of crushing a material that serves as the base material of the battery. Specifically, a method for processing waste batteries according to one embodiment of the present invention may include a step of crushing the battery before performing a heat treatment step. More specifically, the battery crushed material may be obtained by utilizing a device such as a crusher to crush the material that serves as the base material of the battery crushed material. The crushing may include, as a non-limiting example, crushing the waste battery by applying physical or mechanical force and crushing it into a fine powder.

[0034] In one embodiment, the step of crushing the battery may be a crushing method using at least one of shearing, compression, and tensile force. Specifically, the crushing step may be performed by, for example, at least one of a hammer mill, a ball mill, and a stirred ball mill. The hammer mill may perform at least one step of disassembly, punching, and milling, and various types of crushing or grinding devices, such as industrial grinders, may be utilized as non-limiting examples. The step of crushing the battery may separate some large impurities, such as aluminum (Al), copper (Cu), iron (Fe), and plastic, from the composition contained in the battery.

[0035] In one embodiment, the step of crushing the battery may be performed such that the size of the battery crushed material is 100 mm or less. Specifically, the size of the battery crushed material may be 80 mm or less, more specifically, 50 mm or less. When the size of the battery crushed material satisfies the aforementioned range, there is an advantage of excellent process energy efficiency, and when the size of the battery crushed material is larger than the aforementioned range, there is an uneconomical problem due to excessive energy supply during the heat treatment step.

[0036] In one embodiment, prior to the step of crushing the battery, a pretreatment step for preventing explosion or detoxifying the base material of the crushed battery may be included. By including the pretreatment step, the waste battery disposal method removes explosive substances, such as electrolytes within the base material, and by discharging the base material, such as a waste battery, it is possible to increase safety and recover valuable metals and increase productivity when proceeding with the crushing step.

[0037] The step of heat-treating the waste battery crushed material in an atmosphere containing oxygen (O2) may be a step of introducing the waste battery crushed material into a high-temperature reduction furnace capable of raising the temperature to a high temperature to perform a high-temperature reduction reaction of the waste battery crushed material. To perform the heat-treating step, the waste battery crushed material may be filled into the high-temperature reduction furnace, and then the high-temperature reduction furnace may be heated to apply heat to the waste battery crushed material.

[0038] In one embodiment, the heat treatment step may be performed at a temperature above which the oxide containing the valuable metal reaches equilibrium and reduction begins. Specifically, the heat treatment step may be performed at a temperature above which the oxide containing the valuable metal and the metallic liquid reach equilibrium and reduction begins. Specifically, the temperature at which the oxide begins to be reduced may be, for example, 900°C or higher, specifically 1,000°C or higher.

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

[0040] In one embodiment, the heat treatment step may be performed in a temperature range of 1,100 to 1,500 ℃. Specifically, the temperature range may be 1,150 to 1,450 ℃, and more specifically, 1,100 to 1,355 ℃. By performing the heat treatment in the above temperature range, a reducing atmosphere can be maintained where the graphite is not completely burned while being treated at a high temperature.

[0041] If the upper limit of the above range is exceeded, there is a problem of loss due to lithium vaporization, and if the lower limit of the above range is exceeded, there is a problem that the sintering and reduction of alloying elements cannot proceed. In this way, within the above temperature range, the carbon within the crushed material can be burned minimally, allowing the reduction reaction to be performed in a state where carbon dioxide generation is almost non-existent.

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

[0043] The above-mentioned inert gas may include, for example, at least one of argon (Ar), hydrogen (H2), and nitrogen (N2). The above-mentioned hydrocarbon gas refers to an organic compound composed solely of carbon (C) and hydrogen (H), and may refer to, for example, a compound such as methane (CH4). By performing the heat treatment step in the aforementioned gas atmosphere, the problem of the quality of the recovered valuable metal being degraded by external gases, such as impurities, can be prevented.

[0044] In one embodiment, the gas atmosphere may include oxygen (O2). In one embodiment, the partial pressure of the oxygen in the gas atmosphere may be supplied at a level greater than the partial pressure of oxygen at which the lithium oxide in the battery crush is reduced. Specifically, the oxygen may be included in the gas atmosphere during the heat treatment step to react with the graphite in the battery crush to form carbon monoxide.

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

[0046] By satisfying the aforementioned range for the oxygen content in the gas atmosphere, the weight ratio of carbon monoxide and carbon dioxide can be easily controlled by reacting with a portion of the graphite in the battery crushed material within the reduction furnace. Specifically, as the oxygen content in the gas atmosphere is within the aforementioned range, the positive electrode active material in the battery crushed material is reduced by carbon monoxide and a portion of the graphite remaining in the battery crushed material, and the carbon dioxide generated through this reduction can again react with a portion of the graphite remaining in the battery crushed material to produce carbon monoxide. In this way, as the oxygen content is controlled within the aforementioned range, the carbon dioxide content can be minimized and the carbon monoxide content can be continuously and consistently produced.

[0047] In one embodiment, oxygen in the gas atmosphere may be introduced into the reduction furnace by negative pressure. Specifically, the oxygen may be introduced into the reduction furnace by applying a negative pressure in the range of -1 to 20 kPa. By maintaining the negative pressure range, the content of the oxygen in the reduction furnace can be controlled to the aforementioned range.

[0048] In one embodiment, the molar ratio of carbon monoxide to carbon dioxide (CO / CO2) in the flue gas generated from the step of heat-treating the shredded waste battery may be 0.40 to 1.20. Specifically, the molar ratio may be 0.41 to 1.16. The flue gas is generated during the process of heating the shredded waste battery and may be a gas generated inside a high-temperature reduction furnace.

[0049] Specifically, the conditions for the combustion of graphite in the heat treatment step of crushed waste batteries can be determined by the mixing ratio of carbon monoxide and carbon dioxide gases in the gas atmosphere of the heat treatment step. More specifically, the Boudouard reaction of the following reaction equation 1 can determine the stable state between carbon monoxide gas and carbon dioxide gas in the presence of graphite.

[0050] <Reaction Equation 1>

[0051] CO2(g) + C(graphite) = 2CO(g)

[0052] The chemical equilibrium of the above reaction equation 1 generally shifts toward the forward reaction at high temperatures, and it can be confirmed by the following reaction equation 2 that the ratio of carbon monoxide gas to carbon dioxide gas at equilibrium determined under conditions where graphite coexists is determined by the ratio of oxygen gas corresponding to the equilibrium between the two types of gases.

[0053] <Reaction Equation 2>

[0054] CO(g) + 0.5O2(g) = CO2(g)

[0055] According to the above reaction equations 1 and 2, it can be confirmed that by controlling the mixing ratio of oxygen in the gas to a low level, the combustion of graphite can be prevented and the emission of carbon dioxide can be reduced.

[0056] In this manner, crushed waste batteries are treated at high temperature, and an appropriate level of oxygen gas is introduced into the reduction furnace under a reducing atmosphere where graphite is not completely combusted, reacting with a portion of the graphite to control the molar ratio of carbon monoxide to carbon dioxide within the aforementioned range. Consequently, the positive electrode active material within the crushed batteries is reduced by the carbon monoxide generated during the reaction with a portion of the residual graphite material, and the carbon dioxide generated during the reduction process reacts again with the residual graphite to produce carbon monoxide. This offers the advantage of promoting the production of carbon monoxide gas, which can be used as a heat source and reducing agent, and resolving the problem of large CO2 emissions that occur during the conventional dry waste battery recycling process.

[0057] In one embodiment, the method for disposing of waste batteries may satisfy the following Equation 1.

[0058] <Equation 1>

[0059] 0.40 ≤ [A] × [B] ≤ 1.50

[0060] (In Equation 1 above, [A] represents the vol% of oxygen (O2) in the heat treatment atmosphere during the heat treatment step, and [B] represents the molar ratio (CO / CO2) of carbon monoxide (CO) to carbon dioxide (CO2) in the flue gas generated from the heat treatment step.)

[0061]

[0062] Equation 1 above is a value obtained by multiplying the oxygen content in the heat treatment step by the molar ratio of carbon monoxide to carbon dioxide in the flue gas generated in the heat treatment step, and may represent a carbon dioxide emission index in the waste battery heat treatment step. Equation 1 above may satisfy 0.40 to 1.50. Equation 1 above may satisfy 0.460 to 1.340. By satisfying the aforementioned ranges, there is an advantage of high graphite recovery rate and low carbon dioxide emission at the same time.

[0063] If the above Equation 1 exceeds the upper limit of the aforementioned range, there is a problem in that the waste battery shreds are not smoothly reduced due to an excessive influx of oxygen (O2) from the outside air. If the above Equation 1 exceeds the lower limit of the aforementioned range, there is a problem in that the generation of carbon monoxide (CO) or carbon dioxide (CO2) gas from the graphite is not smoothly carried out, and the waste battery shreds are not smoothly reduced.

[0064] In one embodiment, the method for disposing of waste batteries may satisfy the following Equation 2.

[0065] <Equation 2>

[0066] 0.50 ≤ ([A] × [B] × [C] / 1000) ≤ 1.80

[0067] (In Equation 2 above, [A] represents the vol% of oxygen (O2) in the heat treatment atmosphere during the heat treatment step, [B] represents the molar ratio (CO / CO2) of carbon monoxide (CO) to carbon dioxide (CO2) in the flue gas generated from the heat treatment step, and [C] represents the heat treatment temperature (°C) during the heat treatment step.)

[0068] Equation 2 above represents a value obtained by multiplying the oxygen content in the heat treatment step by the molar ratio of carbon monoxide to carbon dioxide in the flue gas generated in the heat treatment step, multiplying this by the heat treatment temperature in the heat treatment step, and dividing the result by 1000, which may represent an indicator of carbon dioxide emissions. Equation 2 above can satisfy a range of 0.50 to 1.80, specifically 0.55 to 1.77. By satisfying the aforementioned range, Equation 2 above has the advantage of a high graphite recovery rate and, at the same time, low carbon dioxide emissions.

[0069] If the above Equation 2 exceeds the upper limit of the aforementioned range, there is a problem in that lithium vaporizes and is lost at high temperatures. If the above Equation 2 exceeds the lower limit of the aforementioned range, there is a problem in that the reduction of the waste battery shreds is not performed smoothly because the temperature is excessively low.

[0070] According to another embodiment of the present invention, a waste battery treatment method relates to a method for treating a waste battery by heat treating the waste battery, comprising the steps of crushing the waste battery and heat treating the crushed waste battery at a temperature above which oxides containing valuable metals within the crushed waste battery begin to be reduced, and satisfying the following Equation 2.

[0071] <Equation 2>

[0072] 0.50 ≤ ([A] × [B] × [C] / 1000) ≤ 1.80

[0073] (In Equation 2 above, [A] represents the vol% of oxygen (O2) in the heat treatment atmosphere during the heat treatment step, [B] represents the molar ratio (CO / CO2) of carbon monoxide (CO) to carbon dioxide (CO2) in the flue gas generated from the heat treatment step, and [C] represents the heat treatment temperature (°C) during the heat treatment step.)

[0074] In one embodiment, the method may include a step of discharging exhaust gas generated from a step of heat-treating crushed waste batteries to the outside of a reduction furnace where the heat treatment is performed. Specifically, exhaust gas containing carbon dioxide and carbon monoxide generated during the heat treatment step may be discharged to the outside of a high-temperature reduction furnace.

[0075] In one embodiment, the exhaust gas may be discharged outside the reduction furnace by negative pressure. Specifically, the exhaust gas may be discharged outside the reduction furnace under negative pressure conditions ranging from 0 to -20 kPa. The exhaust gas may be discharged outside the reduction furnace by utilizing, for example, a component such as a negative pressure pump. The exhaust gas is discharged outside the reduction furnace by the aforementioned method, and the discharged exhaust gas can be detected to determine the operating status.

[0076] In one embodiment, the step of detecting the exhaust gas may determine the operating status of a portion of the gas generated from the step of heat-treating the waste battery crushed material using at least one of gas chromatography, quadrupole mass spectrometry, and non-dispersive infrared absorption method. Gas chromatography is an analytical technique used to separate and analyze compounds that can be vaporized without decomposition, quadrupole mass spectrometry may be a technique for monitoring by generating an electric field through which sample ions pass by combining a high-frequency alternating current potential with a direct current for four electrodes or poles, and non-dispersive infrared absorption method may be a technique for measuring absorbed infrared radiation at its absorption wavelength. More specifically, the step of detecting the exhaust gas may determine the composition and molar ratio within the gas by non-dispersive infrared absorption method.

[0077] In one embodiment, the recovery rate of graphite in the resulting product after the step of discharging the flue gas outside the furnace where the heat treatment is performed may be 85% or higher. Specifically, the recovery rate of graphite may be 90% or higher. The graphite recovery rate is a value measured by the amount of graphite in the resulting product after the heat treatment process relative to the amount of graphite in the crushed waste battery material before being fed into the high-temperature reduction furnace. By undergoing the heat treatment process of the present invention, although a portion of the graphite is consumed by the Bouda reaction, the carbon monoxide generated by the reaction continuously induces the reaction, thereby enabling the acquisition of high-quality valuable metal and graphite materials.

[0078] In one embodiment, the exhaust gas may further include a step of being recirculated to the heat treatment step. By recirculating the exhaust gas containing carbon monoxide back to the heat treatment step, the recovery efficiency of carbon monoxide can be maximized.

[0079] In one embodiment, the method may include a step of separately storing the flue gas. The stored flue gas can be utilized as a heat source or reducing agent for other processes. Specifically, since the flue gas contains a large amount of carbon monoxide, it is economically viable to recycle the gas generated during the process.

[0080]

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

[0082]

[0083] <Experimental Example 1>: Whether or not an oxygen atmosphere is included

[0084] <Example 1> - Oxygen partial pressure 1.0 vol%

[0085] (Waste battery preparation stage)

[0086] The step of preparing the waste battery involved preparing a pretreatment material by removing the outer casing and bolt components, in addition to the positive electrode and the negative electrode, from a waste battery containing components such as a positive electrode, a negative electrode, an outer casing, and bolts.

[0087] Specifically, the anode is Li(Ni 0.6 Co 0.2 Ni 0.2The positive active material composed of O2 is attached to an aluminum (Al) current collector by a binder and contains Li: 22.7 g, Al: 84.0 g, and O: 107 g per 1 kg of cell, and the negative active material is a negative active material composed of graphite attached to a copper (Cu) current collector by a binder and contains Graphite: 210 g and Cu: 161 g per 1 kg of cell. In addition, the electrolyte in the spent battery contains 22 g of LiPF6, 63 g of EC, and 63 g of DMC per 1 kg of cell in the form of a lithium salt such as LiPF6 dissolved in an organic carbonate such as EC (Ethylene carbonate) and DMC (Dimethyl Carbonate); a binder (PVDF) for binding the active materials and current collectors constituting the positive and negative electrodes in the spent battery contains 29 g per 1 kg of cell; and the separator separating the positive and negative electrodes in the spent battery contains 15 g of PP (Poly-ethylene), 4 g of PE (Poly-ethylene), and 3 g of PET (Poly-ethylene terephthalate) per 1 kg of cell, which are polymer materials.

[0088]

[0089] (Battery crushing step)

[0090] The above battery was shredded using a 2-axis 2-stage shredder to a particle size range of 5 to 80 mm. The shredded battery material had a layered structure in which the positive electrode, negative electrode, and separator were stacked in sequence, and the layered structure was stacked in at least one layer, and the size of the battery shred was 100 mm or less. The size of the battery shred refers to the length based on the major axis among the width, length, and height of the battery shred. The shredding was completed within 5 minutes for modules and within 3 minutes for cells.

[0091]

[0092] (Step of heat-treating the battery)

[0093] The above battery was reduced at a high temperature in a high-temperature reduction furnace, and the process was carried out in an atmosphere at 1,350°C, which is the temperature at which the lithium oxide of the battery, for example, crushed battery material, is reduced, and at which the partial pressure of oxygen (O2) gas is 1.0 vol% and the partial pressure of argon (Ar) gas is 99.0 vol%. The oxygen gas was drawn into the high-temperature reduction furnace while maintaining a negative pressure of 0 to -1 kPa due to the external exhaust gas.

[0094] While undergoing the step of heat-treating the battery, exhaust gas was generated in the high-temperature reduction furnace, and the exhaust gas was discharged to the outside while maintaining a negative pressure of 0 to -1 kPa.

[0095]

[0096] <Comparative Example 1> - Oxygen gas not included

[0097] In the step of heat-treating the battery, the gas atmosphere was controlled to have a partial pressure of argon (Ar) gas of 100 vol% and the temperature was 1,348 ℃, except that the procedure was performed in the same manner as Example 1.

[0098]

[0099] <Experimental Example 2> - Oxygen Partial Pressure Control

[0100] <Example 2> - Oxygen partial pressure 2.0 vol%

[0101] In the step of heat-treating the battery, the temperature was controlled to 1,322 ℃ and the gas atmosphere was controlled to a partial pressure of oxygen (O2) gas to 2.0 vol%, except that the procedure was performed in the same manner as Example 1.

[0102]

[0103] <Example 3> - Oxygen partial pressure 0.8 vol%

[0104] In the step of heat-treating the battery, the temperature was controlled to 1,100 ℃ and the gas atmosphere was controlled to a partial pressure of oxygen (O2) gas to 0.8 vol%, except that the procedure was performed in the same manner as Example 1.

[0105]

[0106] <Example 4> - Oxygen partial pressure 0.4 vol%

[0107] In the step of heat-treating the battery, the temperature was controlled to 1,317 ℃ and the gas atmosphere was controlled to a partial pressure of oxygen (O2) gas to 0.4 vol%, except that the procedure was performed in the same manner as Example 1.

[0108]

[0109] <Example 5> - Oxygen partial pressure 2.1 vol%

[0110] In the step of heat-treating the battery, the temperature was controlled to 1,355 ℃ and the gas atmosphere was controlled to a partial pressure of oxygen (O2) gas to 2.1 vol%, except that the procedure was performed in the same manner as Example 1.

[0111]

[0112] <Comparative Example 2> - Oxygen partial pressure upper limit

[0113] The process was carried out in the same manner as Example 1, except that the partial pressure of oxygen (O2) gas was controlled to 15 vol% during the heat treatment step of the battery.

[0114]

[0115] <Comparative Example 3>

[0116] The process was carried out in the same manner as Example 1, except that the temperature was controlled to 872 ℃ and the gas atmosphere was controlled to a partial pressure of oxygen (O2) gas to 0.4 vol% during the heat treatment step of the battery.

[0117]

[0118] Table 1 below shows the composition of the exhaust gas generated in the high-temperature reduction furnace and the moles and mole ratios of the composition when the heat treatment conditions of the heat treatment step according to the embodiments and comparative examples of the present invention are controlled. The composition of the exhaust gas and the moles and mole ratios of the composition in Table 1 below were measured by the following method.

[0119] Mol of carbon monoxide (CO) and carbon dioxide (CO2) [mol in gas]: Carbon monoxide and carbon dioxide generated inside the reduction furnace under negative pressure conditions of 0 to -1 kPa from a high-temperature reduction furnace performing a heat treatment step were released to the outside of the furnace, and the released carbon monoxide and carbon dioxide were measured using non-dispersive infrared absorption.

[0120] Figure 1 shows the CO / CO2 molar ratio according to the oxygen content of an embodiment of the present invention.

[0121] Experimental Example Temperature (°C) Reduction Range Max O2 (%) CO moles [mol] CO2 moles [mol] CO / CO2 molar ratio Formula 1 Formula 2 Example 1 1350 1.09.6 12.7 0.76 0.76 1.026 Example 2 132 22.08.39 12.6 20.6 1.34 1.771 Example 3 1100 0.8 13.7 21.8 0.6 30.5 40.554 Example 4 131 70.4 20.75 17.8 41.16 0.46 40.611 Example 5 135 52.1 3.35 7.1 20.47 0.98 71.337 Comparative Example 1 13480 5.7 0.0 41 42.500 Comparative Example 2135015.01.84.90.375.5507.493 Comparative Example 38720.412.718.80.680.2720.237* Equation 1: [O2] × (CO / CO2)** Equation 2: (Temperature / 1000) × [O2] × (CO / CO2)

[0122]

[0123] Looking at Table 1 and Figure 1 above, it was confirmed that when the maximum oxygen partial pressure within the reduction range satisfies the scope of the present invention and the temperature range satisfies the scope of the present invention, as in Examples 1 to 5, the CO / CO2 molar ratio, Equation 1, and Equation 2 satisfy the scope of the present invention. In contrast, referring to Comparative Example 1, it was confirmed that when heat treatment of a battery is performed in a gas atmosphere that does not contain any oxygen partial pressure, the CO / CO2 molar ratio, Equation 1, and Equation 2 do not satisfy the scope of the present invention because the formation of carbon monoxide required for the reduction of the waste battery is not easy. Furthermore, it was confirmed that the CO / CO2 molar ratio, Equation 1, and Equation 2 do not satisfy the scope of the present invention when the oxygen partial pressure does not satisfy the scope of the present invention, as in Comparative Examples 1 and 2, and when the heat treatment temperature does not satisfy the scope of the present invention, as in Comparative Example 3.

[0124]

[0125] Data regarding the graphite recovery rate and CO2 emissions in the entire process are presented through the waste battery treatment method processed according to the aforementioned examples and comparative examples. The aforementioned graphite recovery rate and CO2 emissions in the entire process were measured by the following method.

[0126] Graphite recovery rate (%): Calculated based on the results of comparing the amount of sample input into the reduction furnace and the graphite content in the effluent after reaction, based on the analysis of the C content of the product by size and magnetic properties according to dry separation of the dry reduction furnace effluent (quantitative analysis using an NDIR sensor of CO(g) emitted by burning the sample).

[0127] CO2 emissions in the entire process: Using a gas analysis device utilizing an NDIR sensor for dry reduction furnace flue gas analysis, the cumulative CO2 emissions at a temperature range satisfying within ± 3% of the target temperature during dry reduction furnace operation were measured by dividing the time satisfying the temperature range.

[0128] CO2 emission reduction effect: Calculated from the C content in the reactant sample, based on the assumption that all C in the sample is completely combusted and emitted into the atmosphere in the form of CO2.

[0129] Experimental Example Graphite Recovery Rate (%) CO2 Emission at Maximum Temperature (L min-1) CO2 Emission Reduction Effect (g C / kg Reactor) Example 1 100 - 52.0 Example 2 7 1.4 9.2 57.8 Example 3 9 2.7 10.7 86.3 Example 4 9 3.6 13.2 81.9 Example 5 8 4.8 23.0 62.8 Comparative Example 2 19.6 6.3 31.1 Comparative Example 3 5 2.2 24.3 28.1

[0130]

[0131] Looking at Table 2 above, it can be seen that there is a difference in graphite recovery rate and CO2 emission reduction effect between the example and the comparative example. Specifically, the graphite recovery rate of the comparative example is significantly lower compared to the example, and it was confirmed that this is because it is reduced to a gas such as CO2.

[0132] The present invention is not limited to the above embodiments and can be manufactured in various different forms, and those skilled in the art will understand that the invention can be implemented in other specific forms without changing the technical concept or essential features of the invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

1. This relates to a method for processing batteries by heat-treating waste batteries, The method includes the step of heat-treating the crushed waste battery material in an atmosphere containing oxygen (O2), A method for disposing of waste batteries satisfying the following Equation 1. <Equation 1> 0.40 ≤ [A] × [B] ≤ 1.50 (In Equation 1 above, [A] represents the vol% of oxygen (O2) in the heat treatment atmosphere during the heat treatment step, and [B] represents the molar ratio (CO / CO2) of carbon monoxide (CO) to carbon dioxide (CO2) in the flue gas generated from the heat treatment step.) 2. In Paragraph 1, In the step of heat-treating the above-mentioned crushed waste battery material in an atmosphere containing oxygen (O2), A method for treating waste batteries in which the oxygen content is 6 vol% or less based on the total volume of 100 vol% of the reduction furnace.

3. In Paragraph 1, The step of heat-treating the above-mentioned waste battery crushed material in an atmosphere containing oxygen (O2) is a method for treating waste batteries performed at a temperature above which oxides containing valuable metals begin to be reduced.

4. In Paragraph 1, A method for treating waste batteries, comprising the step of discharging exhaust gas generated from the step of heat-treating the crushed waste batteries to the outside of the furnace where the heat treatment is performed.

5. In Paragraph 4, A method for treating waste batteries in which the exhaust gas is discharged to the outside under negative pressure conditions of 0 to -20 kPa.

6. In Paragraph 1, Prior to the step of heat-treating the above-mentioned crushed waste batteries, A method for disposing of waste batteries including a step of crushing waste batteries.

7. In Paragraph 4, A method for treating waste batteries in which the recovery rate of graphite in the resulting product is 85% or higher, after undergoing the step of discharging the above-mentioned exhaust gas to the outside of the furnace where heat treatment is performed.

8. In Paragraph 4, A method for treating waste batteries, further comprising the step of recirculating the discharged exhaust gas to the heat treatment step.

9. In Paragraph 1, A method for treating waste batteries, wherein the molar ratio (CO / CO2) of carbon monoxide (CO) to carbon dioxide (CO2) in the flue gas generated from the step of heat-treating the above-mentioned waste battery crushed material is 0.40 to 1.

20.

10. A method for processing batteries by heat-treating waste batteries, Step of crushing waste batteries; and The method includes the step of heat-treating the waste battery crushed material at a temperature above which oxides containing valuable metals within the waste battery crushed material begin to be reduced, A method for disposing of waste batteries satisfying the following Equation 2. <Equation 2> 0.50 ≤ ([A] × [B] × [C] / 1000) ≤ 1.80 (In Equation 2 above, [A] represents the vol% of oxygen (O2) in the heat treatment atmosphere during the heat treatment step, [B] represents the molar ratio (CO / CO2) of carbon monoxide (CO) to carbon dioxide (CO2) in the flue gas generated from the heat treatment step, and [C] represents the heat treatment temperature (°C) during the heat treatment step.) 11. In Paragraph 10, A method for treating waste batteries in which the above heat treatment step is performed in the range of 1,100 to 1,500 ℃.

12. In Paragraph 10, A method for treating waste batteries in which the above heat treatment step is performed at an oxygen partial pressure above which lithium oxide in the battery crushed material is reduced.

13. In Paragraph 10, A method for treating waste batteries in which the oxygen (O2) content in the heat treatment atmosphere during the above heat treatment step is 6.0 vol% or less based on the total volume of 100 vol% of the reduction furnace.

14. In Paragraph 10, A method for treating waste batteries, wherein the molar ratio (CO / CO2) of carbon monoxide (CO) to carbon dioxide (CO2) in the flue gas generated from the step of heat-treating the above-mentioned waste battery crushed material is 0.40 to 1.

20.

15. In Paragraph 10, A method for processing waste batteries in which the step of crushing the waste battery is performed so that the size of the crushed battery material is 100 mm or less.

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