Aqueous solution, and method for recycling waste lithium metal

Abstract

One embodiment of the present invention for accomplishing the described objective relates to an aqueous solution comprising a solvent, and an additive added to the solvent, wherein the additive comprises at least one selected from a lithium compound, an alkali metal, an alcohol, adiponitrile (AN), succinonitrile (SN), silicon nitride, B and Si. The aqueous solution is used to recycle waste lithium metal, and thus can prevent ignition and be applied to recycling of a large amount of waste lithium metal.

Description

Aqueous solution and waste lithium metal recycling method

[0001] The present invention relates to a lithium aqueous solution and a method for recycling waste lithium metal.

[0002] Waste lithium metal refers to lithium metal scrap or by-products containing lithium metal generated during the manufacturing process of lithium metal products. Like lithium metal, it is highly chemically reactive and forms lithium nitride and lithium oxide upon contact with external air, and can generate very high reaction heat and hydrogen gas upon contact with water.

[0003] Waste lithium metal, which is highly chemically reactive, is difficult to recycle. Although some is recovered as lithium metal by melting it at high temperatures, it is generally disposed of through incineration or landfill due to low economic feasibility.

[0004] Embodiments of the present invention provide a method for recycling waste lithium metal using an aqueous solution.

[0005] One embodiment of the present invention for achieving the purpose described above discloses an aqueous solution comprising a solvent and an additive introduced into the solvent, wherein the additive comprises one or more selected from a lithium compound, an alkali metal, an alcohol, adiponitrile (AN), succinonitrile (SN), silicon nitride, B, or Si.

[0006] Another embodiment of the present invention for achieving the above-described purpose discloses a method for recycling waste lithium metal, comprising the steps of preparing an aqueous solution and introducing waste lithium metal into the prepared aqueous solution and reacting it.

[0007] The waste lithium metal recycling method according to the embodiments of the present invention prevents ignition by recycling waste lithium metal using an aqueous solution with improved stability, and can be applied to the recycling of large quantities of waste lithium metal.

[0008] FIG. 1 is a flowchart schematically illustrating a waste lithium metal recycling method according to one embodiment of the present invention.

[0009] Figure 2 is a flowchart schematically illustrating another example of the waste lithium metal recycling method of Figure 1.

[0010] One embodiment of the present invention for achieving the purpose described above discloses an aqueous solution comprising a solvent and an additive introduced into the solvent, wherein the additive comprises one or more selected from a lithium compound, an alkali metal, an alcohol, adiponitrile (AN), succinonitrile (SN), silicon nitride, B, or Si.

[0011] In this embodiment, the additive may be included in an amount of 0.1 wt% to 40 wt% based on the total aqueous solution.

[0012] In this embodiment, the additive may be included in an amount of 10 ppm to 100,000 ppm based on the total aqueous solution.

[0013] Another embodiment of the present invention for achieving the above-described purpose discloses a method for recycling waste lithium metal, comprising the steps of preparing an aqueous solution and introducing waste lithium metal into the prepared aqueous solution and reacting it.

[0014] In this embodiment, a step of removing impurities may be further included.

[0015] In this embodiment, the reaction step may be carried out at -5°C to 50°C.

[0016] In the present embodiment, the reaction step may be carried out in an inert atmosphere or a vacuum atmosphere.

[0017] The present invention is capable of various modifications and may have various embodiments; specific embodiments are illustrated in the drawings and described in detail in the detailed description. The effects and features of the present invention, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the drawings. However, the present invention is not limited to the embodiments disclosed below but can be implemented in various forms.

[0018] In the following embodiments, terms such as first, second, etc. are used not in a limiting sense, but for the purpose of distinguishing one component from another component.

[0019] In the following examples, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0020] In the following embodiments, terms such as "include" or "have" mean that the features or components described in the specification are present, and do not preclude the possibility that one or more other features or components may be added.

[0021] In the following embodiments, when a part such as a film, region, or component is described as being on or above another part, it includes not only cases where it is directly on top of another part, but also cases where another film, region, or component is interposed in between.

[0022] In the drawings, the size of components may be exaggerated or reduced for convenience of explanation. For example, the size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, so the present invention is not necessarily limited to what is illustrated.

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings, and when describing with reference to the drawings, identical or corresponding components will be given the same reference numerals.

[0024] FIG. 1 is a flowchart schematically illustrating a waste lithium metal recycling method according to one embodiment of the present invention.

[0025] Referring to FIG. 1, a waste lithium metal recycling method may include the step of preparing an aqueous solution (S100) and the step of introducing waste lithium metal into the prepared aqueous solution and reacting it under vacuum conditions (S200).

[0026] In the step of preparing the aqueous solution (S100), the aqueous solution can be prepared by dissolving an additive in water (H2O), which is a solvent.

[0027] Water may include, for example, ultrapure water or distilled water, and may be in a state where ionic components, etc., have been removed.

[0028] Additives may be introduced during the waste lithium metal input step described later to suppress the rapid exothermic reaction that occurs when waste lithium metal reacts with water when it is introduced into the aqueous solution. Depending on the concentration of the additive contained in the aqueous solution, the reaction between the waste lithium metal and water that occurs during the introduction of the waste lithium metal described later can be controlled, thereby enabling the safe recovery of the waste lithium metal.

[0029] According to a method for preparing an aqueous solution according to one embodiment of the present invention, the additive may be included in the aqueous solution in an amount of 0.1 wt% to 40 wt% based on the total aqueous solution.

[0030] If the amount of additive contained in the aqueous solution is less than 0.1 wt%, the waste lithium metal may react rapidly with water when waste lithium metal is added, potentially causing a fire. If the amount of additive contained in the aqueous solution exceeds 40 wt%, there is a problem that the amount of waste lithium metal that can be reacted with the aqueous solution decreases.

[0031] The additive may include, for example, one or more selected from lithium compounds, alkali metals, alcohols, adiponitrile (AN), succinonitrile (SN), silicon nitride, B, or Si.

[0032] Specifically, the lithium compound may include one or more selected from lithium hydroxide (LiOH), lithium carbonate (Li2CO3), lithium fluoride (LiF), or lithium chloride (LiCl). The alcohol may include one or more selected from methanol, ethanol, or propanol. The alkali metal may include one or more selected from sodium (Na), potassium (K), and calcium (Ca).

[0033] As an optional example, a lithium compound may be added separately from the lithium compound added as an additive, and the additional lithium compound may be 5g to 35g based on 1000ml of aqueous solution. When a lithium compound is added separately from the additive in this way, a rapid exothermic reaction can be suppressed when waste lithium metal is added to the aqueous solution.

[0034] Meanwhile, in order to suppress the exothermic reaction rate between the lithium compound and water during the process of preparing the aqueous solution, the temperature of the aqueous solution can be controlled to 5°C or lower.

[0035] According to a method for preparing an aqueous solution according to another embodiment of the present invention, the concentration of the additive included in the aqueous solution may be 10 ppm to 100,000 ppm.

[0036] When the concentration of additives contained in the aqueous solution is less than 10 ppm, the waste lithium metal may react rapidly with water when waste lithium metal is added, potentially causing a fire. When waste lithium metal is added, if the concentration of lithium salt contained in the lithium aqueous solution exceeds 100,000 ppm, there is a problem that the amount of waste lithium metal that can be reacted with the aqueous solution decreases.

[0037] In an optional example, when the concentration of the additive contained in the aqueous solution is 10 ppm to 100,000 ppm, the additive may include lithium hydroxide (LiOH), lithium carbonate (Li2CO3), or lithium chloride (LiCl).

[0038] In the step (S200) of introducing waste lithium metal into the prepared lithium aqueous solution and reacting it, the waste lithium metal may be introduced into the aqueous solution and reacted, and the reaction may be carried out, for example, in a chamber sealed from the outside, and the inside of the chamber may include an inert gas atmosphere or a vacuum atmosphere.

[0039] By carrying out the reaction between the waste lithium metal and the aqueous solution in an inert gas atmosphere or a vacuum atmosphere, the reaction gases in the air are removed, and the exothermic reaction can be suppressed.

[0040] Inert gases used in an inert gas atmosphere may include argon (Ar) or helium (He).

[0041] In a vacuum atmosphere, hydrogen gas generated inside the chamber can be discharged to the outside to maintain the vacuum inside the chamber, and as hydrogen gas with a risk of explosion is discharged and removed to the outside, the risk of ignition can be further reduced.

[0042] At this time, the vacuum condition inside the chamber is 10,000 Pa to 1 x 10⁻⁶ -6 It can be pa, and the vacuum inside the chamber is 1x10 -6 If the vacuum is less than pa, the aqueous solution may vaporize and the reaction may slow down, and if the vacuum inside the chamber exceeds 10,000 pa, the removal of hydrogen gas may not be smooth.

[0043] Meanwhile, when reacting the aqueous solution containing the additive with the waste lithium metal, the temperature of the aqueous solution can be controlled to -5℃ to 50℃.

[0044] When reacting with waste lithium metal, if the temperature of the aqueous solution is below -5℃, the reaction between the waste lithium metal and the aqueous solution slows down, which may reduce work efficiency, and when the temperature of the aqueous solution is above 50℃, it may be difficult to control the exothermic reaction when reacting with the waste lithium metal and the aqueous solution.

[0045] Waste lithium metal may include, for example, by-products containing lithium scrap or lithium metal that are generated during the product manufacturing process or recovered from waste batteries using known technology.

[0046] Meanwhile, waste lithium metal is highly chemically reactive, just like lithium metal, and can form lithium nitride and lithium oxide upon contact with external air, and can generate very high heat of reaction with hydrogen gas upon contact with water.

[0047] Therefore, if waste lithium metal is dissolved by adding it to a general aqueous solution, there is a risk of ignition, and the resulting oxidation of the waste lithium metal may make it difficult to recover high-quality lithium.

[0048] However, the aqueous solution according to the embodiment of the present invention contains an additive of a certain concentration, thereby preventing a rapid reaction from occurring when waste lithium metal is input, which can reduce the frequency of fire occurrence and prevent the oxidation of waste lithium metal due to fire, thereby enabling the recovery of high-quality lithium.

[0049] Meanwhile, when waste lithium metal is introduced into an aqueous solution, the waste lithium metal can be produced in the form of a lithium aqueous solution, and a high-concentration lithium aqueous solution can be obtained.

[0050] In addition, waste lithium metal produced in the form of a lithium aqueous solution can be safe as there is no risk of ignition, and by applying this to large quantities of waste lithium metal, it is possible to safely produce waste lithium metal in the form of a lithium aqueous solution.

[0051] As an optional example, when waste lithium metal is introduced into an aqueous solution to which a lithium compound is added as an additive, the waste lithium metal can be produced in the form of lithium hydroxide (LiOH) by a reaction such as Formula 1, and as the waste lithium metal exists in the lithium aqueous solution in the form of lithium hydroxide (LiOH), a high concentration of lithium aqueous solution can be obtained.

[0052] In addition, waste lithium metal produced in the form of lithium hydroxide (LiOH) can be safe as there is no risk of ignition, and this allows for the safe production of waste lithium metal into the form of lithium hydroxide (LiOH) by applying it to large quantities of waste lithium metal.

[0053]

[0054] (Chemical Formula 1)

[0055] 2Li + 2H2O → 2LiOH + H2

[0056]

[0057] Figure 2 is a flowchart schematically illustrating another example of the waste metal lithium recycling method of Figure 1.

[0058] Referring to FIG. 2, a waste metal lithium recycling method may include the step of preparing an aqueous solution (S110), the step of introducing waste lithium metal into the prepared lithium aqueous solution and reacting it (S210), and the step of removing impurities (S310).

[0059] In the step of preparing the aqueous solution (S110), the aqueous solution can be prepared by dissolving an additive in water (H2O), which is a solvent.

[0060] Water may include, for example, ultrapure water or distilled water, and may be in a state where ionic components, etc., have been removed.

[0061] Additives may be introduced during the waste lithium metal input step described later to suppress the rapid exothermic reaction that occurs when waste lithium metal reacts with water when it is introduced into the aqueous solution. Depending on the concentration of the additive contained in the lithium aqueous solution, the reaction between the waste lithium metal and water that occurs during the introduction of the waste lithium metal described later can be controlled, thereby enabling the safe recovery of the waste lithium metal.

[0062] According to a method for preparing an aqueous solution according to one embodiment of the present invention, the additive may be included in the aqueous solution in an amount of 0.1 wt% to 40 wt% based on the total aqueous solution.

[0063] If the amount of additive contained in the aqueous solution is less than 0.1 wt%, the waste lithium metal may react rapidly with water when waste lithium metal is added, potentially causing a fire. If the amount of additive contained in the aqueous solution exceeds 40 wt%, there is a problem that the amount of waste lithium metal that can be reacted with the aqueous solution decreases.

[0064] The additive may include, for example, one or more selected from lithium compounds, alkali metals, alcohols, adiponitrile (AN), succinonitrile (SN), silicon nitride, B, and Si.

[0065] Specifically, the lithium compound may include one or more selected from lithium hydroxide (LiOH), lithium carbonate (Li2CO3), lithium fluoride (LiF), or lithium chloride (LiCl). The alcohol may include one or more selected from methanol, ethanol, or propanol. The alkali metal may include one or more selected from sodium (Na), potassium (K), and calcium (Ca).

[0066] As an optional example, a lithium compound may be added separately from the lithium compound added as an additive, and the additional lithium compound may be 5g to 35g based on 1000ml of aqueous solution. When a lithium compound is added separately from the additive in this way, a rapid exothermic reaction can be suppressed when waste lithium metal is added to the aqueous solution.

[0067] Meanwhile, in order to suppress the exothermic reaction rate between the lithium compound and water during the process of preparing the aqueous solution, the temperature of the aqueous solution can be controlled to 5°C or lower.

[0068] According to a method for preparing an aqueous solution according to another embodiment of the present invention, the concentration of the additive included in the aqueous solution may be 10 ppm to 100,000 ppm.

[0069] When the concentration of additives contained in the aqueous solution is less than 10 ppm, the waste lithium metal may react rapidly with water when waste lithium metal is added, potentially causing a fire. When waste lithium metal is added, if the concentration of lithium salt contained in the lithium aqueous solution exceeds 100,000 ppm, there is a problem that the amount of waste lithium metal that can be reacted with the aqueous solution decreases.

[0070] In an optional example, when the concentration of the additive contained in the aqueous solution is 10 ppm to 100,000 ppm, the additive may include lithium hydroxide (LiOH), lithium carbonate (Li2CO3), or lithium chloride (LiCl).

[0071] In the step (S210) of introducing waste lithium metal into the prepared lithium aqueous solution and reacting it, the waste lithium metal may be introduced into the aqueous solution and reacted, and the reaction may be carried out, for example, in a chamber sealed from the outside, and the inside of the chamber may include an inert gas atmosphere or a vacuum atmosphere.

[0072] By carrying out the reaction between the waste lithium metal and the aqueous solution in an inert gas atmosphere or a vacuum atmosphere, the reaction gases in the air are removed, and the exothermic reaction can be suppressed.

[0073] Inert gases used in an inert gas atmosphere may include argon (Ar) or helium (He).

[0074] In a vacuum atmosphere, hydrogen gas generated inside the chamber can be discharged to the outside to maintain the vacuum inside the chamber, and as hydrogen gas with a risk of explosion is discharged and removed to the outside, the risk of ignition can be further reduced.

[0075] At this time, the vacuum condition inside the chamber is 10,000 Pa to 1 x 10⁻⁶ -6 It can be pa, and the vacuum inside the chamber is 1x10 -6 If the vacuum is less than pa, the aqueous solution may vaporize and the reaction may slow down, and if the vacuum inside the chamber exceeds 10,000 pa, the removal of hydrogen gas may not be smooth.

[0076] Meanwhile, when reacting the aqueous solution containing the additive with the waste lithium metal, the temperature of the aqueous solution can be controlled to -5℃ to 50℃.

[0077] When reacting with waste lithium metal, if the temperature of the aqueous solution is below -5℃, the reaction between the waste lithium metal and the aqueous solution slows down, which may reduce work efficiency, and when the temperature of the aqueous solution is above 50℃, it may be difficult to control the exothermic reaction when reacting with the waste lithium metal and the aqueous solution.

[0078] Waste lithium metal may include, for example, by-products containing lithium scrap or lithium metal that are generated during the product manufacturing process or recovered from waste batteries using known technology.

[0079] Meanwhile, waste lithium metal is highly chemically reactive, just like lithium metal, and can form lithium nitride and lithium oxide upon contact with external air, and can generate very high heat of reaction with hydrogen gas upon contact with water.

[0080] Therefore, if waste lithium metal is dissolved by adding it to a general aqueous solution, there is a risk of ignition, and the resulting oxidation of the waste lithium metal may make it difficult to recover high-quality lithium.

[0081] However, the aqueous solution according to the embodiment of the present invention contains an additive of a certain concentration, thereby preventing a rapid reaction from occurring when waste lithium metal is input, which can reduce the frequency of fire occurrence and prevent the oxidation of waste lithium metal due to fire, thereby enabling the recovery of high-quality lithium.

[0082] Meanwhile, when waste lithium metal is introduced into an aqueous solution, the waste lithium metal can be produced in the form of a lithium aqueous solution, and a high-concentration lithium aqueous solution can be obtained.

[0083] In addition, waste lithium metal produced in the form of a lithium aqueous solution can be safe as there is no risk of ignition, and by applying this to large quantities of waste lithium metal, it is possible to safely produce waste lithium metal in the form of a lithium aqueous solution.

[0084] In the step of removing impurities (S310), waste lithium metal is reacted with an aqueous solution to produce lithium hydroxide (LiOH), thereby removing impurities contained in the aqueous solution that has become high in concentration.

[0085] The removal of impurities can be achieved, for example, through filtering and the addition of NaCO3. When NaCO3 is added, the impurities precipitate, and the waste lithium metal mixed with the impurities can be produced as lithium carbonate (Li2CO3). The precipitation of impurities can lower the solubility in the aqueous solution, and the precipitated impurities can be separated through filtering.

[0086] Consequently, the waste lithium metal recycling method according to one embodiment of the present invention can improve stability and produce high-quality lithium compounds by using an aqueous solution containing an additive of a certain concentration to produce lithium hydroxide (LiOH) from waste lithium metal, and can be applied to the recycling of large quantities of waste lithium metal.

[0087]

[0088] (Example 1)

[0089] 50g of waste lithium metal was added to 1000ml of an aqueous solution at 5°C containing 10g of lithium hydroxide and 2wt% of ethanol as additives under an Argon gas atmosphere, and ignition was checked. This was repeated 5 times under the same conditions.

[0090]

[0091] (Example 2)

[0092] 50g of waste lithium metal was added to 1000ml of an aqueous solution at 5℃ containing 20g of lithium hydroxide and 1wt% of adiponitrile under an argon gas atmosphere, and ignition was checked. This was repeated 5 times under the same conditions.

[0093]

[0094] (Example 3)

[0095] 50g of waste lithium metal was added to 1000ml of an aqueous solution at 5°C containing 10g of lithium hydroxide and 2wt% succinonitrile under a vacuum atmosphere, and ignition was checked. This was repeated 5 times under the same conditions.

[0096]

[0097] (Example 4)

[0098] 50g of waste lithium metal was added to 1000ml of an aqueous solution at 20°C containing 30g of lithium hydroxide and 5wt% ethanol under an Argon atmosphere, and ignition was checked. This was repeated 5 times under the same conditions.

[0099]

[0100] (Comparative Example 1)

[0101] 50g of waste lithium metal was added to 1000ml of water at 20℃, and ignition was checked. This was repeated 5 times under the same conditions.

[0102]

[0103] Classification Fire Occurrence Frequency Example 12 Example 21 Example 30 Example 41 Comparative Example 15

[0104] Referring to Table 1, the frequency of fire occurrence according to the experimental example can be confirmed.

[0105] In the case of Examples 1 to 4, in which additives and lithium hydroxide were added, it can be confirmed that the frequency of fire occurrence was reduced compared to Comparative Example 1, which used pure water, and in the case of Example 3, in which 10g of lithium hydroxide and 2wt% of succinonitrile were added, it can be confirmed that no fire occurred. This is because, compared to Example 2, in which 20g of lithium hydroxide and 1wt% of adiponitrile were added, the amount of lithium hydroxide decreased but the amount of additive increased; through this, it can be confirmed that the rapid exothermic reaction that occurs when waste lithium metal reacts with water can be suppressed by increasing the amount of additive.

[0106] In addition, when comparing Example 1 and Example 4, it can be seen that the frequency of fire occurrence is reduced more effectively when the amount of added lithium hydroxide and ethanol is increased, regardless of temperature. Through this, it can be confirmed that the amount of added lithium hydroxide and ethanol has a greater influence on the frequency of fire occurrence than the temperature condition.

[0107] Consequently, the aqueous solution according to the embodiments of the present invention contains additives and lithium compounds at a constant concentration, thereby preventing a rapid reaction when waste lithium metal is input, which can reduce the frequency of fires and prevent the oxidation of waste lithium metal due to fire, thus enabling the recovery of high-quality lithium.

[0108]

[0109] (Example 5)

[0110] 10 g of waste lithium metal was added to 1,000 ml of an aqueous solution with a lithium salt concentration of 1,000 ppm at room temperature, and ignition was checked. This was repeated 5 times under the same conditions.

[0111]

[0112] (Example 6)

[0113] 10 g of waste lithium metal was added to 1,000 ml of an aqueous solution with a lithium salt concentration of 5,000 ppm at room temperature, and ignition was checked. This was repeated 5 times under the same conditions.

[0114]

[0115] (Example 7)

[0116] 10 g of waste lithium metal was added to 1,000 ml of an aqueous solution with a lithium salt concentration of 50,000 ppm at room temperature, and ignition was checked. This was repeated 5 times under the same conditions.

[0117]

[0118] (Example 8)

[0119] 10 g of waste lithium metal was added to 1,000 ml of an aqueous solution with a lithium salt concentration of 1,000 ppm at room temperature under a vacuum of 10 Pa, and ignition was checked. This was repeated 5 times under the same conditions.

[0120]

[0121] (Example 9)

[0122] 10g of waste lithium metal in 1000ml of an aqueous solution with a lithium salt concentration of 1000ppm at room temperature under vacuum 1x10 -3 It was injected at pa and the ignition status was checked. This was repeated 5 times under the same conditions.

[0123]

[0124] (Comparative Example 2)

[0125] 10g of waste lithium metal was added to 1000ml of pure solution under room temperature vacuum conditions, and ignition was checked. This was repeated 5 times under the same conditions.

[0126]

[0127] Classification Fire Occurrence Frequency Example 52 Example 61 Example 70 Example 81 Example 90 Comparative Example 25

[0128] Referring to Table 2, the frequency of fire occurrence according to the experimental example can be confirmed.

[0129] In the case of Examples 1 to 3, in which lithium salt was introduced at a certain concentration, it can be confirmed that the frequency of fire occurrence was reduced compared to Comparative Example 1, which used pure water, and in the case of Example 3, in which the concentration of lithium salt was 50,000 ppm, it can be confirmed that no fire occurred.

[0130] In addition, looking at Examples 1, 2, and 3, where the lithium salt concentrations are 1,000 ppm, 5,000 ppm, and 50,000 ppm, respectively, it can be seen that the frequency of fire decreases as the lithium salt concentration increases. This means that the higher the lithium salt concentration in the lithium aqueous solution, the more lithium is already dissolved in the solution, so a rapid reaction can be prevented when waste lithium metal is added. Therefore, it can be seen that the frequency of fire decreases when using an aqueous solution with a high lithium salt concentration.

[0131] In addition, looking at Examples 4 and 5, it can be seen that compared to Example 1, the frequency of fire decreases as the vacuum level increases at the same lithium salt concentration. This indicates that as the vacuum level increases, hydrogen gas can be easily removed, which lowers the frequency of fire.

[0132] Meanwhile, applying a vacuum can prevent the occurrence of fire even if the concentration of lithium salt contained in the lithium aqueous solution is lowered. By lowering the concentration of lithium salt, the solubility within the aqueous solution can be reduced, which allows the solution to react with a larger amount of waste lithium metal, thereby improving the efficiency of waste lithium metal recycling.

[0133] Consequently, the waste lithium metal recycling method according to one embodiment of the present invention uses an aqueous solution containing an additive and a lithium salt at a constant concentration, and by controlling temperature and vacuum conditions, it can prevent fire during the reaction between the aqueous solution and the waste lithium metal, thereby improving stability and enabling the production of a high-quality lithium aqueous solution by preventing fire, and thereby enabling the recycling of a large amount of waste lithium metal.

[0134] As such, the present invention has been described with reference to an embodiment illustrated in the drawings, but this is merely illustrative, and those skilled in the art will understand that various modifications and variations of the embodiments are possible therefrom. Accordingly, the true technical scope of protection of the present invention should be determined by the technical spirit of the appended claims.

Claims

1. Solvent; and Includes an additive introduced into the above solvent; The above additive is an aqueous solution comprising one or more selected from lithium compounds, alkali metals, alcohols, adiponitrile (AN), succinonitrile (SN), silicon nitride, B, or Si.

2. In Paragraph 1, The above additive is an aqueous solution containing 0.1 wt% to 40 wt% based on the total aqueous solution.

3. In Paragraph 1, The above additive is an aqueous solution containing 10 ppm to 100,000 ppm based on the total aqueous solution.

4. Step of preparing an aqueous solution; and A method for recycling waste lithium metal comprising the step of introducing waste lithium metal into the prepared aqueous solution and reacting it.

5. In Paragraph 4, A method for recycling waste lithium metal, further comprising a step of removing impurities.

6. In Paragraph 4, A waste lithium metal recycling method in which the above reaction step is carried out at -5℃ to 50℃.

7. In Paragraph 4, A waste lithium metal recycling method in which the above reaction step is carried out in an inert atmosphere or a vacuum atmosphere.

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