Method for recovering valuable metal from positive electrode material of waste lithium battery through arc plasma reduction in hydrogen atmosphere

Abstract

The present invention relates to a method for recovering valuable metals from a positive electrode material of a waste lithium battery through arc plasma reduction in a hydrogen atmosphere and, more specifically, to a method for recovering valuable metals from a positive electrode material of a waste lithium battery through arc plasma reduction in a hydrogen atmosphere, the method comprising, by using high-temperature arc plasma generated in a hydrogen atmosphere, recovering Ni, Co, and Fe metals reduced from LiNi0.8Co0.1Mn0.1O2 (NCM811; lithium nickel cobalt manganese oxide), LiCoO2 (LCO; lithium cobalt oxide), LiFePO4 (LFP; lithium iron phosphate), and the like included in a positive electrode material of a waste lithium battery. According to the present invention, in a process of recovering valuable metals from the positive electrode material of the waste lithium battery, there are effects of increasing reduction efficiency and accelerating the process relative to conventional methods using argon gas, and recovering valuable metals such as Ni, Co, and Fe remaining in the waste battery through quick reaction speeds.

Description

Method for recovering valuable metals from spent lithium battery cathode materials using arc plasma reduction in a hydrogen atmosphere

[0001] The present invention relates to a method for recovering valuable metals from spent lithium battery cathode materials using arc plasma reduction in a hydrogen atmosphere, and more specifically, to a method for recovering LiNi contained in the cathode material of spent lithium batteries using high-temperature arc plasma generated in a hydrogen atmosphere. 0.8 Co 0.1 Mn 0.1 The present invention relates to a method for recovering valuable metals from spent lithium battery cathode materials using arc plasma reduction in a hydrogen atmosphere, characterized by recovering Ni, Co, and Fe metals reduced from O2 (NCM811; Lithium Nickel Cobalt Manganese Oxide), LiCoO2 (LCO; Lithium Cobalt Oxide), LiFePO4 (LFP; Lithium Iron Phosphate), etc.

[0002] Currently, as interest in eco-friendly energy gains global attention, the volume of waste batteries is rapidly increasing alongside the rise in the use of secondary batteries. According to statistical surveys, electric vehicle sales in 2023 reached 14 million units, a sixfold increase compared to 2018; consequently, the number of scrapped vehicles is projected to reach 4.11 million in 2030 and 42.77 million in 2040.

[0003] Next-generation waste battery recycling technology can alleviate environmental issues and raw material supply shortages, and reduce dependence on overseas imports of cathode materials, which are currently landfilled only in specific countries. Global companies and research institutions are devoting significant effort to developing waste battery recycling technologies, and the battery recycling market is projected to grow to approximately 200 trillion won by 2040.

[0004] These spent batteries contain lithium nickel cobalt manganese oxide (LiNi) composed of transition metals 0.8 Co 0.1 Mn 0.1O2, NCM811), lithium cobalt oxide (LiCoO2) 2, LCO), lithium iron oxide (LiFePO4) 4, It includes cathode materials composed of LFP. There is a growing trend of research and demand for technology regarding the recycling of valuable metals within spent lithium battery cathode materials, such as Co and Ni, which have traditionally been expensive, and Fe, which can be utilized in various aspects of daily life.

[0005] The prior patents related to waste lithium battery recycling technology currently in use are as follows.

[0006] Methods include a method for crushing and dry heat-treating cell-unit batteries and separating them through particle size separation and magnetic separation (Patent Application No. 10-2023-0038360), a method for recovering precursors such as Ni, Co, and Mn using strong sulfates (Patent Application No. 10-2021-0122698), a method for controlling the alloy size of Ni using sulfuric acid and a complex heat treatment process (Patent Application No. 10-2022-0130603), a method for extracting Co using a complex process in an acidic atmosphere utilizing a mixed solvent (Patent Application No. 10-2022-0029821), a method for obtaining lithium hydroxide through a relatively complex process (Patent Application No. 10-2020-0166203), and a method for recovering cathode material particles using an oxygen atmosphere and sodium hydroxide (Patent Application No. 10-2021-0120343).

[0007] Conventional battery recycling methods, such as the technology described above, apply a process in which waste lithium batteries are crushed and ground into black powder and recycled using wet and dry methods. However, wet and dry methods have problems in that the process is complex, time-consuming, and has a low yield, and is not environmentally friendly because it generates toxic gases and involves repeated oxidation and reduction processes.

[0008] These differences can be summarized as follows.

[0009] Prior Art No. Differences from the Present Invention Patent Application No. 10-2023-0038360 Complex process of crushing, grinding, freezing, and heat treatment Patent Application No. 10-2022-0130603 Use of sulfuric acid and complex heat treatment process Patent Application No. 10-2022-0029821 Method for extracting Co using a complex process in an acidic atmosphere utilizing a mixed solvent Patent Application No. 10-2021-0122698 Not true recycling through eco-friendly reduction using very strong sulfates Patent Application No. 10-2021-0120343 Recovery of cathode material particles through a method including an oxygen atmosphere and sodium hydroxide Patent Application No. 10-2020-0166203 Obtaining lithium hydroxide through a complex process

[0010] The present invention presents a Hydrogen Plasma Reduction (HPR) method that extracts Ni, Co, and Fe from waste batteries very quickly and simply by utilizing hydrogen and a plasma arc, deviating from conventional methods applied in the prior art that are harmful to the environment, such as strong acids and strong bases, and are complex and time-consuming.

[0011] However, there exists a prior patent that applies a technology for reducing and separating waste metals using conventional plasma reduction technology, which differs from the present invention as follows.

[0012] The invention of Patent Application No. 10-2019-0128689 is technically different from the present invention in that it utilizes plasma to process waste aluminum (metal) and extracts high-purity aluminum without using hydrogen, and in the case of waste aluminum, aluminum metal is extracted from metal rather than ceramic.

[0013] Furthermore, the inventions of Patent Applications No. 10-2016-0025143 and No. 10-2014-0047960 utilized metallic titanium in the technology for reducing impurities in titanium by generating arc plasma in a hydrogen atmosphere, and in the case of recovering copper from copper-containing waste, they utilized hydrogen generated from LPG gas in addition to recovering metal from metal, which differs from the present invention in that hydrogen is directly added.

[0014] In addition, the invention of Patent Application No. 10-1998-0058249 presents a technology for recovering valuable metals from industrial waste using plasma; however, this invention also does not use hydrogen and differs in that waste batteries are compositionally different from industrial waste.

[0015] Prior Art No. Differences from the present invention Patent Application No. 10-2019-0128689: Extraction of metal from metal. No hydrogen used when utilizing plasma. Patent Application No. 10-2016-0025143: Extraction of metal from metal. Patent Application No. 10-2014-0047960: Extraction of metal from metal. LPG gas used when utilizing plasma. Patent Application No. 10-1998-0058249: Industrial waste and waste batteries have different compositions; no hydrogen used when utilizing plasma.

[0016] Therefore, the present invention can be considered an original technology that is differentiated from prior patents in that it applies a plasma utilizing hydrogen and a technology for recovering valuable metals by reducing oxide waste battery cathode materials.

[0017]

[0018] The present invention, aimed at solving the aforementioned problems, provides a method for recovering valuable metals from spent lithium battery cathode materials using arc plasma reduction in a hydrogen atmosphere, which enables the rapid and efficient recovery of valuable metals contained in spent lithium battery cathode materials by reducing oxide cathode materials in an arc plasma environment in a hydrogen atmosphere.

[0019] In addition, the present invention aims to provide a simple recovery method for extracting oxidized cathode materials of NCM, LCO, and LFP batteries in the form of high-purity Ni, Co, and Fe metals, and to provide a method for recovering valuable metals from spent lithium battery cathode materials using arc plasma reduction in a hydrogen atmosphere, which is an eco-friendly method that does not use strong acids or generate harmful substances.

[0020] According to the present invention, in a process for recovering valuable metals from spent lithium battery cathode materials, the reduction efficiency is increased and the process speed is accelerated compared to a method utilizing general Ar gas, and through the rapid reaction speed, there is an effect of efficiently recovering valuable metals such as Ni, Co, and Fe remaining in the spent battery.

[0021] FIG. 1 is a flowchart showing the process of a method for recovering valuable metals according to an embodiment of the present invention.

[0022] FIG. 2 is a conceptual diagram showing a reaction process carrying out the process illustrated in FIG. 1.

[0023] Figure 3 is a conceptual diagram showing the detailed structure of a plasma chamber.

[0024] Figure 4 is a photograph showing the changes in the properties of the cathode material as it undergoes a plasma reduction process.

[0025] Figure 5 is a photograph taken comparing the composition of the cathode material before and after the plasma reduction process.

[0026] Figure 6 is a graph showing the composition ratio of valuable metals after reduction of the NCM cathode material.

[0027] Figure 7 is a graph showing the composition ratio of valuable metals after reduction of the LCO cathode material.

[0028] Figure 8 is a graph showing the composition ratio of valuable metals after reduction of the LFP cathode material.

[0029]

[0030] **Explanation of Symbols for Key Parts of the Drawing**

[0031] 10 : Cathode material before reduction 20 : Cathode material after reduction

[0032] 30 : Magnetic material 100 : Hydrogen plasma reduction device

[0033] 102: Chamber 104: Cathode

[0034] 106 : Anode 108 : Supply tank

[0035] 110: Gas inlet 112: Pressure gauge

[0036] 114 : Thermometer

[0037]

[0038] The present invention, devised to solve the aforementioned problems, is a method for recovering valuable metals contained in the cathode material of a spent lithium battery using arc plasma, comprising: a first step of preparing the cathode material contained in the spent lithium battery; a second step of exposing the cathode material to a plasma arc to induce a reduction reaction; and a third step of separating the plasma-reduced valuable metals and impurity particles.

[0039] The above-mentioned cathode material is one of NCM, LCO, and LFP, and the above-mentioned valuable metal is characterized by being one or more of nickel, cobalt, and iron included in the above-mentioned cathode material.

[0040] The first step above is characterized by grinding the cathode material separated from the waste lithium battery into a powder form.

[0041] The above first step is characterized by compressing the anode material processed into powder form in a mold to form pellets.

[0042] The second step above is characterized by introducing the oxidized anode material into a hydrogen plasma reduction device (100) and reducing the anode material in a hydrogen atmosphere.

[0043] The above hydrogen plasma reduction device (100) comprises: a chamber (102) having a space formed inside; a cathode (104) installed on the inner upper surface of the chamber (102); an anode (106) installed on the inner bottom surface of the chamber (102); a power supply unit connected to the cathode (104) and the anode (106) to supply power; a supply tank (108) for supplying gas for plasma generation; and a gas inlet (110) formed on one side of the chamber (102) and connected to a gas pipe connected to the supply tank (108).

[0044] The above supply tank (108) is characterized by storing hydrogen and argon gas and supplying them into the interior of the chamber (102).

[0045] The above supply tank (108) is characterized by supplying gas containing 90% argon and 10% hydrogen.

[0046] The above third step is characterized by bringing a magnetic material (30) having magnetic force close to the anode material (20) after reduction to separate the valuable metal.

[0047] It further includes a fourth step of washing and post-processing the separated valuable metals.

[0048] Hereinafter, with reference to the drawings, a "method for recovering valuable metals from spent lithium battery cathode material using arc plasma reduction in a hydrogen atmosphere" according to an embodiment of the present invention will be described.

[0049] FIG. 1 is a flowchart showing the process of a method for recovering valuable metals according to an embodiment of the present invention, FIG. 2 is a conceptual diagram showing the reaction process carrying out the process shown in FIG. 1, FIG. 3 is a conceptual diagram showing the detailed structure of a plasma chamber, and FIG. 4 is a photograph showing the appearance of a positive electrode material changing its characteristics as it undergoes a plasma reduction process.

[0050] To carry out the method for recovering valuable metals according to the present invention, a four-step process as illustrated in FIG. 1 is performed.

[0051] First, as a first step, a cathode material contained in a waste lithium battery is prepared. (S102) In the present invention, metal elements were separated using NCM, LCO, and LFP cathode materials, but other cathode materials may be used.

[0052] The entire assembly, including the aluminum anode and the anode active material coated thereon, is separated from the spent lithium battery. When separating the anode material from the spent lithium battery, it is preferable to separate the anode material itself, excluding the negative electrode and separator contained within the battery cell. Since various methods can be applied to the technology for separating the anode material from the spent lithium battery, the present invention does not specifically limit the separation method.

[0053] The separated cathode material may contain a binder.

[0054] It is desirable to appropriately grind the separated cathode material to a size that can be fed into a plasma chamber.

[0055] In addition, valuable metals may be obtained by utilizing cathode materials processed into powder form without undergoing the process of separating and crushing the cathode materials from spent lithium batteries. In the case of cathode material powder, valuable metals can be obtained through reduction and separation using any one of crushed NCM811, LCO, or LFP powders. Although cathode materials processed into powder form may be fed directly without processing, it is preferable to pelletize the cathode material using a mold with a diameter of approximately 10 mm to 20 mm and feed it into a reduction chamber. Most preferably, pelletization can be carried out by compressing approximately 200 mg or more of cathode material to a pressure of 600 MPa or more using a mold with a diameter of 13 mm.

[0056] As the next step, the cathode material is exposed to a plasma arc in a hydrogen atmosphere to induce a reduction reaction. (S104)

[0057] The cathode material containing the separated current collector or the cathode material powder in its initial pelletized state is introduced into a hydrogen plasma reduction device (100) to remove oxygen through a reduction reaction.

[0058] A hydrogen plasma reduction device (100) has a cathode (104) and an anode (106) installed inside a chamber (102), and a supply tank (108) for injecting gas for plasma generation may be provided on the outside. A gas pipe connected to the supply tank (108) is connected to a gas inlet (110) formed on one side of the chamber (102), and hydrogen and argon gases supplied from the supply tank (108) flow into the chamber (102) through the gas inlet (110).

[0059] A pressure gauge (112) and a thermometer (114) for measuring internal pressure and temperature, respectively, may be installed in the chamber (102).

[0060] Typically, the cathode (104) can be installed on the upper inner surface of the chamber (102) and extend vertically through the upper surface. The anode (106) is installed on the lower inner surface of the chamber (102), and the anode material (10) before reduction can be placed on the anode (106).

[0061] A power supply unit (not shown in the drawing) is connected to the cathode (104) and the anode (106), and power is supplied from the power supply unit to generate plasma between the cathode (104) and the anode (106).

[0062] When power is supplied to the cathode (104) and the anode (106) while supplying a plasma gas, such as argon gas, through the gas inlet (110), an arc is generated at the electrical contact, changing the argon gas into a plasma state. The heat generated from the plasma melts the anode material (10) placed on the anode (106) before reduction, and the hydrogen supplied along with the argon gas causes a reduction reaction. The hydrogen combines with the oxygen bound to the valuable metal and is discharged, leaving the anode material (20) after reduction. The valuable metal remains as a metal element inside the anode material (20) after reduction.

[0063] In the present invention, the anode material (10) before reduction is placed inside a Cu water-cooled chamber (maintained at 20°C), and then an arc plasma is generated in an argon and hydrogen mixed gas atmosphere while supplying a gas containing 90% argon and 10% hydrogen to reduce the oxide anode material at a very high temperature.

[0064] It is preferable to set the pressure inside the chamber (102) to be in the range of -0.8 bar to -0.4 bar during the reduction reaction. It is also preferable to set the distance between the anode material specimen to be reduced and the plasma node to be about 1 cm. Furthermore, it is preferable to set the time for generating a plasma arc to cause the reduction reaction to occur to be 2 to 10 seconds.

[0065] In order to obtain a sufficient amount of valuable metal from the introduced cathode material, it is desirable to repeat the above plasma reduction reaction about 2 to 6 times while setting the pressure, time, and the distance between the cathode material specimen and the plasma node to be the same.

[0066] In the next three steps, plasma-reduced valuable metals, current collectors, and impurity particles are separated. (S106)

[0067] After the plasma reduction reaction is completed, the valuable metals (nickel, cobalt, iron, etc.) contained in the reduced anode material (20) extracted from the chamber (102) have magnetism. By utilizing this magnetism, valuable metal elements such as nickel, cobalt, and iron can be separated. In the present invention, a magnetic body (30), such as a neodymium magnet having a magnetic force of 0.7 T or more, is used, and the magnetic body (30) is brought close to the reduced anode material (20) to separate them. Since the aluminum current collector contained in the anode material (10) before reduction is a paramagnetic material, it does not adhere to the magnetic body (30), so it can be separated from the valuable metal elements.

[0068] As the final fourth step, the separated valuable metals undergo post-processing steps such as washing. (S108)

[0069] The properties of the cathode material change through such a reduction reaction, and the experimental results regarding this are explained with reference to the diagram.

[0070] Figure 5 is a photograph showing a comparison of the composition of the cathode material before and after the plasma reduction process, Figure 6 is a graph showing the composition ratio of valuable metals after the reduction of the NCM cathode material, Figure 7 is a graph showing the composition ratio of valuable metals after the reduction of the LCO cathode material, and Figure 8 is a graph showing the composition ratio of valuable metals after the reduction of the LFP cathode material.

[0071] The valuable metal collected through the hydrogen plasma reduction reaction has a shape that is distinctly different from the unreduced NCM, LCO, and LFP cathode materials. Fig. 5 shows scanning electron microscope images of the cathode material before and after the reduction reaction. Additionally, Figs. 6 to 8 show the metal composition of the cathode material (20) after reduction.

[0072] Referring to Figures 5 to 8, the composition was analyzed using scanning electron microscopy energy dispersive X-ray spectroscopy and atomic tomography. As a result, it was confirmed that the oxygen content of the spent lithium battery cathode material before reduction was relatively high, but the oxygen content of the metal collected after plasma reduction reaction was very low.

[0073] As shown in Figure 6, when metal elements were collected from the NCM811 cathode material, it was confirmed that high-purity nickel metal was recovered because the composition of nickel (Ni) was 97.409 at% and the composition of cobalt (Co) was 2.504 at%.

[0074] And, as shown in Fig. 7, it was confirmed that the composition of cobalt (Co) in the LCO cathode material was 99.872 at%.

[0075] And, as shown in Fig. 8, in the case of the LFP cathode material, the iron (Fe) composition was observed to be 98.078 at% and the phosphorus (P) composition was 1.811 at%.

[0076] Thus, it has been confirmed that valuable metals such as nickel, cobalt, and iron of very high purity can be obtained from each type of spent lithium battery cathode material through the hydrogen plasma reduction reaction of the present invention. Therefore, it will be possible to design alloys containing nickel, cobalt, and iron by utilizing the high-purity metals recovered from NCM, LCO, and LFP cathode materials.

[0077] Although preferred embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art will understand that the technical configuration of the present invention described above may be implemented in other specific forms without altering the technical concept or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive, and the scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention.

Claims

1. A method for recovering valuable metals contained in the cathode material of a spent lithium battery using arc plasma, A first step of preparing a cathode material included in the above-mentioned spent lithium battery; A second step of exposing the above-mentioned anode material to a plasma arc to induce a reduction reaction; A method for recovering valuable metals from spent lithium battery cathode materials using arc plasma reduction in a hydrogen atmosphere, comprising a third step of separating plasma-reduced valuable metals and impurity particles.

2. In Paragraph 1, A method for recovering valuable metals from spent lithium battery cathode materials using arc plasma reduction in a hydrogen atmosphere, characterized in that the cathode material is one of NCM, LCO, and LFP, and the valuable metal is one or more of nickel, cobalt, and iron contained in the cathode material.

3. In Paragraph 1, A method for recovering valuable metals from a spent lithium battery cathode material using arc plasma reduction in a hydrogen atmosphere, wherein the first step above is characterized by crushing the cathode material separated from the spent lithium battery into a powder form.

4. In Paragraph 1, A method for recovering valuable metals from spent lithium battery cathode materials using arc plasma reduction in a hydrogen atmosphere, wherein the first step above is characterized by compressing the cathode material processed into powder form in a mold to form pellets.

5. In Paragraph 1, The above second step is characterized by introducing the oxidized cathode material into a hydrogen plasma reduction device (100) and reducing the cathode material in a hydrogen atmosphere, a method for recovering valuable metals from waste lithium battery cathode material using arc plasma reduction in a hydrogen atmosphere.

6. In Paragraph 5, The above hydrogen plasma reduction device (100) is A chamber (102) in which a space is formed inside; A cathode (104) installed on the inner upper surface of the chamber (102); An anode (106) installed on the inner bottom surface of the chamber (102); A power supply unit connected to the above-mentioned negative electrode (104) and the above-mentioned positive electrode (106) to supply power; A supply tank (108) for supplying gas for plasma generation; A method for recovering valuable metals from waste lithium battery cathode material using arc plasma reduction in a hydrogen atmosphere, comprising: a gas inlet (110) formed on one side of the chamber (102) and connected to a gas pipe connected to the supply tank (108).

7. In Paragraph 6, A method for recovering valuable metals from waste lithium battery cathode material using arc plasma reduction in a hydrogen atmosphere, characterized in that the supply tank (108) stores hydrogen and argon gas and supplies it into the chamber (102).

8. In Paragraph 7, A method for recovering valuable metals from spent lithium battery cathode material using arc plasma reduction in a hydrogen atmosphere, characterized in that the supply tank (108) above supplies a gas containing 90% argon and 10% hydrogen.

9. In Paragraph 1, A method for recovering valuable metals from a waste lithium battery cathode material using arc plasma reduction in a hydrogen atmosphere, characterized in that the third step above involves bringing a magnetic material (30) having magnetic force close to the cathode material (20) after reduction to separate the valuable metals.

10. In Paragraph 1, A method for recovering valuable metals from spent lithium battery cathode materials using arc plasma reduction in a hydrogen atmosphere, further comprising a fourth step of washing and post-treating the separated valuable metals.

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