Method for processing waste battery

Abstract

The present invention relates to a method for recovering lithium from process water that has been obtained from a waste battery, wherein a precipitate including an aluminum-based hydroxide compound containing lithium ions is recovered from the process water.

Description

Disposal method for waste batteries

[0001] The present invention relates to a method for treating waste batteries, and more specifically, to a technology for producing a lithium compound from high concentrations of lithium ions contained in the water of a secondary screening process for recovering graphite from a high-temperature reduction reactant of waste batteries.

[0002] The present invention claims priority based on Korean Patent Application No. 10-2024-0191924 filed on December 19, 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] In the wet smelting and solvent extraction processes performed to recover valuable metals, which are cathode active materials, from black powder manufactured for the recycling of the above-mentioned battery, the presence of graphite has a negative effect on the leaching rate and leaching time of valuable metals such as lithium (Li), nickel (Ni), cobalt (Co), and manganese (Mn). Accordingly, in order to remove the graphite acting as an impurity, the existing black powder manufacturing process completely oxidizes the graphite, which is waste carbon dust, and emits it as carbon dioxide (CO2), which poses a problem in terms of environmental regulations regarding the reduction of carbon dioxide.

[0006] As the value of graphite, a cathode active material, has increased due to China's recent export restrictions, the value of graphite recycling is also rising. Consequently, active research is being conducted on the issue of graphite recycling with environmental considerations.

[0007] Accordingly, interest in the process of recovering graphite from the aforementioned waste batteries is increasing. However, since the process water remaining after graphite recovery also contains a high concentration of lithium ions, recovering this lithium ion offers economic advantages; therefore, there is a need for research on methods to recover the lithium ions separately.

[0008] The technical problem that the present invention aims to solve is to easily recover high-purity graphite from raw materials, such as black powder obtained from waste batteries, and to extract high-concentration lithium ions contained in process water into a lithium compound during the recovery process.

[0009] A method for treating waste batteries according to one embodiment of the present invention relates to a method for recovering lithium from process water obtained from waste batteries, and can recover a precipitate containing an aluminum-based hydroxide compound containing lithium ions from said process water.

[0010] In one embodiment, the precipitate may further comprise lithium carbonate (Li2CO3). In one embodiment, the precipitate may comprise, in weight percent, an aluminum-based hydroxide compound containing 80 to 95 weight percent of lithium ions and the remainder being lithium carbonate.

[0011] In one embodiment, the aluminum-based hydroxide compound containing lithium ions may be LiAl2(OH)7. In one embodiment, the process water obtained from the waste battery may be contained in a sorting process for recovering graphite from the high-temperature reduction reaction product obtained from the waste battery.

[0012] In one embodiment, the process water obtained from the waste battery may be obtained by the steps of preparing a slurry containing a reactant recovered from the waste battery, performing magnetic separation on the slurry, and performing flotation separation on a non-magnetic material recovered from the magnetic separation.

[0013] In one embodiment, the step of performing magnetic separation on the slurry may perform a plurality of magnetic separations. In one embodiment, between the steps of performing the plurality of magnetic separations, a step of crushing a magnetic material may be included.

[0014] In one embodiment, after the step of performing magnetic separation on the slurry, the method may include the step of performing flotation separation on the non-magnetic material recovered from the magnetic separation.

[0015] In one embodiment, the flotation separation may be a step of separating a hydrophilic lithium compound and copper. In one embodiment, the step of performing flotation separation on the non-magnetic product recovered from the magnetic separation may be a step of recovering hydrophobic graphite.

[0016] In one embodiment, the precipitate may further include an aluminum removal process.

[0017] According to one embodiment of the present invention, a method for treating waste batteries can simplify the lithium purification process by recovering a precipitate containing an aluminum-based hydroxide compound containing lithium ions from process water obtained from waste batteries, thereby simply removing only aluminum as an impurity.

[0018] FIG. 1 is an XRD graph of a precipitate according to one embodiment of the present invention.

[0019] 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.

[0020] 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.

[0021] When it is stated that one part is "above" or "on" another part, it may be directly above or on the other part, or other parts may be involved in between. In contrast, when it is stated that one part is "directly above" another part, no other parts are interposed in between.

[0022] 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.

[0023] A battery processing method according to one embodiment of the present invention relates to a method for recovering lithium from process water obtained from waste batteries, wherein the method involves recovering a precipitate containing an aluminum-based hydroxide compound containing lithium ions from said process water. The inventors confirmed that a significant concentration of lithium exists in a dissolved state within the process water used during the wet separation process of valuable metals and graphite from waste batteries. Accordingly, it was found that the lithium purification process can be simplified if the dissolved high concentration of lithium is recovered as a precipitate containing an aluminum-based hydroxide compound containing lithium ions in order to purify it more simply and efficiently.

[0024] The process water obtained from the above waste battery may be obtained by going through the steps of preparing a slurry containing reactants recovered from the waste battery, performing magnetic separation on the slurry, and performing flotation separation on the non-magnetic products recovered from the magnetic separation.

[0025] The reactant recovered from the above waste battery may be the result of performing a reduction heat treatment at a high temperature on the crushed material after undergoing the step of crushing or crushing a cell containing a plurality of lithium-ion batteries, a module containing a plurality of cells, or a pack containing a plurality of modules. Specifically, the waste battery may include end-of-life battery cells, positive electrode materials such as scrap, jelly rolls, and slurry constituting the waste battery, defective products generated during the manufacturing process, residues inside the manufacturing process, and by-products such as generated debris.

[0026] The reactant recovered from the above-mentioned waste battery may be a reactant that has undergone a step of grinding or crushing. Specifically, the grinding or crushing step may be a step of crushing the waste battery by applying physical or mechanical force and a step of finely grinding it into powder.

[0027] Specifically, 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 waste battery may separate some large impurities among the impurities contained in the waste battery, such as aluminum (Al), copper (Cu), iron (Fe), and plastic.

[0028] In one embodiment, the crushing step may be performed such that the size of the waste battery crushed material is 100 mm or less. Specifically, the size of the waste battery crushed material may be 80 mm or less, more specifically, 50 mm or less. When the size of the waste 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.

[0029] In one embodiment, prior to the step of crushing the waste 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 treatment method removes explosive substances, such as electrolytes within the base material, and by discharging the base material, such as the waste battery, it is possible to increase safety and improve the recovery of valuable metals and graphite and productivity when proceeding with the crushing step.

[0030] The step of performing a reduction heat treatment on the crushed waste battery at a high temperature may be a step of dry heat treatment on the crushed waste battery. Specifically, the step of dry heat treatment may be a step of introducing the crushed waste battery into a high-temperature reduction furnace capable of raising the temperature to a high temperature to perform a high-temperature reduction reaction of the crushed waste battery. To perform the step of dry heat treatment, the crushed waste battery may be filled into the high-temperature reduction furnace, and then the high-temperature reduction furnace may be heated to apply heat to the crushed waste battery.

[0031] In one embodiment, the dry heat treatment step may be performed at a temperature above which the oxide containing the valuable metal reaches equilibrium and reduction begins. Specifically, the dry 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.

[0032] In one embodiment, the dry heat treatment step may be performed in a temperature range of 800 to 1,500 ℃. Specifically, the temperature range may be 1,000 to 1,500 ℃, more specifically 1,100 to 1,450 ℃. 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.

[0033] 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.

[0034] In one embodiment, the dry heat treatment step may be performed in a gas atmosphere of at least one of an inert gas, carbon dioxide (CO2), carbon monoxide (CO), and 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.

[0035] The above inert gas may include, for example, at least one of argon (Ar), hydrogen (H2), and nitrogen (N2). The above hydrocarbon gas refers to an organic compound composed only of carbon (C) and hydrogen (H), and may refer to, for example, a compound such as methane (CH4). By performing the dry 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.

[0036] 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 is included in the gas atmosphere during the dry heat treatment step to react with the graphite in the battery crush to form carbon monoxide, thereby minimizing the emission of carbon dioxide.

[0037] The step of preparing a slurry containing the reactant recovered from the waste battery described above may involve adding water to the reactant recovered from the waste battery obtained through the aforementioned pretreatment process to prepare a slurry satisfying a predetermined range of slurry concentration. In one embodiment, the range of the slurry concentration may be 10 to 20%.

[0038] The step of performing magnetic separation on the above slurry may be a step for recovering an alloy containing a valuable metal that is a magnetic body and a non-magnetic body within the slurry. Specifically, the valuable metal may refer to nickel (Ni), cobalt (Co), manganese (Mn), and lithium (Li).

[0039] The magnetic material may include the aforementioned valuable metal and may be a material alloyed with the aforementioned valuable metal. The material alloyed with the valuable metal may include, for example, a material alloyed with Ni, Co, or Mn and an oxide containing lithium that is combined with said alloyed material. The oxide containing lithium may be, for example, a material such as lithium aluminum oxide, like LiAlO2. The non-magnetic material may be graphite containing carbon and an oxide containing lithium separated from said material alloyed with the valuable metal.

[0040] In one embodiment, the magnetic separation step may be performed in the range of 1,000 to 2,000 Gauss. Specifically, by performing the magnetic separation step, magnetic materials and non-magnetic materials among the reactants recovered from the waste battery can be easily separated, and a separate separation process can be performed for the magnetic materials and the non-magnetic materials. Through this, valuable metals can be easily recovered from the magnetic materials, and graphite can be easily recovered from the non-magnetic materials.

[0041] In one embodiment, a particle size separation step may be performed on the reactant recovered from the waste battery prior to the magnetic separation step. Specifically, the particle size separation step may include a step of separating materials of 1,500 microns or less. Specifically, the particle size separation step may include a step of separating materials of 1,200 microns or less, more specifically 1,000 microns or less. Through the particle size separation step, valuable metals and graphite can be easily recovered even from small reactants having the aforementioned particle size range, thereby increasing the quality of the recovered valuable metals and graphite.

[0042] The method may include a step of performing flotation separation on the above-mentioned non-magnetic material. Specifically, the step of separating hydrophobic graphite from the above-mentioned non-magnetic material may be performed as a flotation separation step. More specifically, the flotation separation step may utilize bubbles generated by blowing air into a pulp in which the reactants are suspended. Specifically, the flotation separation step may be a method in which substances with hydrophobic surface properties attached to bubbles by the air and floating on the water surface, while substances with hydrophilic surface properties remaining in the pulp.

[0043] The step of performing flotation separation on the above-mentioned non-magnetic material may specifically separate a hydrophilic lithium compound and copper from the above-mentioned non-magnetic material. By separating the hydrophilic material from the hydrophobic material, the recovery rate of valuable metals can be improved.

[0044] In one embodiment, the process water obtained from the waste battery may be the process water used in the aforementioned graphite flotation separation process. Utilizing the process water used in the graphite flotation separation process has the advantage of excellent recovery efficiency because the lithium content is dissolved at a high concentration.

[0045] In one embodiment, a precipitate containing an aluminum-based hydroxide compound containing lithium ions can be recovered from the process water. In one embodiment, the aluminum-based hydroxide compound containing lithium ions can be used as a raw material for a lithium purification process by precipitating lithium ions in the process water in the form of LiAl2(OH)7. Specifically, the compound in the form of LiAl2(OH)7 can improve the economic efficiency of subsequent processes by removing only the Al element without a process for removing other impurities in the lithium leaching process.

[0046] In one embodiment, the precipitate may further include lithium carbonate (Li2CO3). For example, if the process water is the process water used in the flotation process of graphite, lithium ions may react with carbon to form lithium carbonate as well as aluminum-based hydroxide compounds.

[0047] In one embodiment, the precipitate may comprise, in weight percent, 80 to 95 weight percent of an aluminum-based hydroxide compound containing lithium ions and the remainder being lithium carbonate. By including a large amount of the aluminum-based hydroxide compound containing lithium ions in the precipitate, the lithium purification process can be simplified if only Al is removed separately as an impurity.

[0048] In one embodiment, the precipitate may further include an aluminum removal process. The aluminum removal process may be, for example, a process for removing aluminum as an impurity. Specifically, by performing an aluminum removal process on the precipitate to remove an aluminum-based hydroxide compound containing lithium ions, the lithium purification process can be simplified.

[0049]

[0050] 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.

[0051]

[0052] <Experimental Example>

[0053] A reactant discharged through a high-temperature reduction process of waste batteries was prepared, and said reactant is black powder comprising large, flat unreacted particles generated from Al cases or cell partitions, an alloy containing nickel (Ni), cobalt (Co), or manganese (Mn), a lithium (Li) compound containing lithium and aluminum, and graphite (C).

[0054] Specifically, to separate NCM alloy, graphite, lithium compounds, copper, etc. from high-temperature reduction reactants, a slurry with a slurry concentration of about 15% (20 kg reactant / 130 kg total) × 100 = 15%, 20 kg of high-temperature reduction reactant + 110 kg of water = Total 130 kg) was prepared and wet beneficiation was performed.

[0055] The above wet beneficiation separation involved performing primary wet magnetic separation at a 15% slurry concentration under 3000 Gauss conditions to recover the magnetic NCM alloy, and subsequently, the primary magnetic product was 33.7 μm (D V (50)) The material was ground to a particle size. Afterwards, secondary wet magnetic separation was performed on the ground material at a slurry concentration of 10% or less and under 3000 Gauss conditions.

[0056] Subsequently, to recover hydrophobic graphite, flotation was performed on the primary non-magnetic product using Kerosene and MIBC as reagents under conditions of a slurry concentration of 20% or less and a stirring speed of 1000 rpm. In addition, to separate hydrophilic lithium compounds and copper, a wet specific gravity separation step was added for the non-suspended material from the flotation.

[0057] Flotation separation was performed on the non-magnetic material to recover hydrophobic graphite from the above non-magnetic material. In addition, a wet specific gravity separation process was performed on the non-suspended material from the flotation separation to separate hydrophilic lithium compounds and copper.

[0058] At this time, it was confirmed that lithium exists in a dissolved state at a significant concentration within the process water obtained during the step of performing flotation separation on the non-magnetic material for graphite recovery.

[0059] Table 1 below shows the results of the elemental analysis within the above process water.

[0060] Elemental Concentration (%) FeSiAlMnCuNiCoLiCaMgPWNbTiZnZrBNa Ecuton Number <0.0100.4119.5<0.010<0.010<0.010<0.010<0.0100.410.20<0.010<0.010<0.010<0.010<0.010<0.010<0.0100.0500.065

[0061] Looking at Table 1 above, it can be seen that the elements in the process water for graphite recovery contain a large amount of lithium.

[0062] Precipitates existing as approximately 90% LiAlOH-type compounds and some 10% Li2CO3 were recovered from the above process water using an evaporation method.

[0063] FIG. 1 is an XRD graph of a precipitate according to one embodiment of the present invention.

[0064] Table 2 below shows the XRD simplified quantitative evaluation results of lithium compounds in the precipitate recovered from the above process water.

[0065] PrecipitatesLithium Aluminum Hydroxide Hydrate (%)89.2Zabuyelite (%)10.8

[0066] Looking at Table 2 and Figure 1 above, it was confirmed that the precipitate recovered from the process water contains approximately 89.2% of an aluminum-based hydroxide compound containing lithium in the form of LiAl2(OH)7 and approximately 10.8% of lithium carbonate. The precipitate contains a large amount of LiAl2(OH)7, and by removing only the Al element from the LiAl2(OH)7 without a process to remove other impurities during the lithium leaching process, high-purity lithium can be obtained, thereby ensuring the economic feasibility of subsequent processes.

[0067] 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. A method for recovering lithium from process water obtained from waste batteries, A method for treating waste batteries to recover a precipitate containing an aluminum-based hydroxide compound containing lithium ions from the above process water.

2. In Paragraph 1, The above-mentioned precipitate is a method for treating waste batteries that further includes lithium carbonate (Li2CO3).

3. In Paragraph 1, A method for treating waste batteries, wherein the above-mentioned precipitate comprises, in weight percent, an aluminum-based hydroxide compound containing 80 to 95 weight percent of lithium ions and the remainder being lithium carbonate.

4. In Paragraph 1, A method for treating waste batteries in which the above-mentioned aluminum-based hydroxide compound containing lithium ions is LiAl2(OH)7.

5. In Paragraph 1, A method for treating waste batteries containing process water obtained from the above waste battery in a sorting process for recovering graphite from a high-temperature reduction reaction product obtained from the waste battery.

6. In Paragraph 1, The process water obtained from the above waste battery is, A step of preparing a slurry containing a reactant recovered from the above-mentioned waste battery; A step of performing magnetic separation on the above slurry; and A step of performing float separation on the non-magnetic material recovered from the above magnetic separation; A method for disposing of waste batteries obtained through the process.

7. In Paragraph 6, The step of performing magnetic separation on the above slurry is: A method for processing waste batteries by performing multiple magnetic separations.

8. In Paragraph 7, A method for processing waste batteries comprising a step of crushing a magnetic material between the steps of performing the plurality of magnetic separations above.

9. In Paragraph 7, After the step of performing magnetic separation on the above slurry, A method for treating waste batteries comprising the step of performing flotation separation on a non-magnetic material recovered from the above magnetic separation.

10. In Paragraph 9, The above flotation is a method for treating waste batteries, which is a step of separating hydrophilic lithium compounds and copper.

11. In Paragraph 6, A method for treating waste batteries in which the step of performing flotation separation on the non-magnetic product recovered from the above magnetic separation is a step of recovering hydrophobic graphite.

12. In Paragraph 1, The above-mentioned precipitate is a method for treating waste batteries that further includes an aluminum removal process.

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