A method for simultaneously or continuously recovering lithium fluoride and a liquid containing hexafluorophosphate from an electrolyte containing lithium hexafluorophosphate

Abstract

The present invention relates to a method for simultaneously recovering a liquid containing hexafluorophosphate (PF6-) and lithium fluoride (LiF) from an electrolyte containing lithium hexafluorophosphate (LiPF6) or for continuously recovering them, and may include the steps of recovering the liquid containing hexafluorophosphate (PF6-) and recovering lithium fluoride (LiF).

Description

Technology Field

[0001] The present invention relates to a solution comprising lithium hexafluorophosphate (LiPF6), wherein the hexafluorophosphate (PF6) - The present invention relates to a method for simultaneously recovering a liquid containing lithium fluoride (LiF) and lithium fluoride, or for recovering lithium fluoride continuously, and to a method for recovering valuable materials from an electrolyte, such as that from waste batteries, through a simple and economical process in the industrial field. Background Technology

[0003] The electrolyte for secondary batteries is a medium that facilitates the movement of ions, such as lithium ions, between the positive and negative electrodes, and contains an electrolyte salt and an organic solvent, and depending on the function, includes additives. Typically, lithium hexafluorophosphate (LiPF6), which is inexpensive and general-purpose, is used as the electrolyte salt.

[0004] Secondary batteries, such as those used in electric vehicles, have a lifespan of about 5 to 10 years. After that, their performance deteriorates, leading to problems such as reduced driving range, the risk of explosion, and slowed charging speed. Therefore, disposal or recycling is required, and recently, countries and companies have been showing great interest in recycling secondary batteries.

[0005] In addition, safe and economical treatment of organic solvents and fluorine compounds in the electrolyte of lithium secondary batteries is required.

[0006] Meanwhile, lithium fluoride (LiF) can be used as a reactant to produce lithium hexafluorophosphate (LiPF6).

[0007] More specifically, lithium hexafluorophosphate (LiPF6) can be prepared by reacting phosphorus pentachloride with lithium fluoride (LiF).

[0008] <Reaction Equation>

[0009] PCl5 + LiF + 5HF -> LiPF6+ 5HCl

[0010] Meanwhile, hexafluorophosphate (PF6) - Liquids containing salts, such as liquids containing salts, have an electrochemical range and are environmentally friendly, so they can be applied in many fields such as metal electrodeposition, lithium batteries, organic electrosynthesis, sensors, and capacitors. The problem to be solved

[0012] As an objective, the present invention provides a valuable material, hexafluorophosphate (PF6), from an electrolyte containing lithium hexafluorophosphate (LiPF6) through a simple, environmentally friendly, and economical process. - The present invention aims to provide a method for simultaneously recovering a liquid containing ) and lithium fluoride (LiF) or recovering them continuously. means of solving the problem

[0014] The present invention relates to a solution comprising lithium hexafluorophosphate (LiPF6), wherein the hexafluorophosphate (PF6) - This invention relates to a method for simultaneously recovering a liquid containing ) and lithium fluoride (LiF) or recovering them continuously.

[0015] Hexafluorophosphate (PF6) according to one aspect of the present invention- A method for recovering a liquid containing ) and lithium fluoride (LiF) is hexafluorophosphate (PF6 - It may include a step of recovering a liquid containing ); and a step of recovering lithium fluoride (LiF).

[0016] In one embodiment, the hexafluorophosphate (PF6) - The method may include the steps of: recovering a liquid containing ); and recovering the lithium fluoride (LiF); prior to that, introducing a first solvent into an electrolyte containing lithium hexafluorophosphate (LiPF6), and then separating a first solvent layer containing lithium hexafluorophosphate (LiPF6).

[0017] In one embodiment, the pH of the first solvent may be 6 to 8.

[0018] In one embodiment, the first solvent may be water.

[0019] In one embodiment, the hexafluorophosphate (PF6) - The step of recovering the liquid containing ) may include the step of introducing a ‘halogen anion X-containing salt’.

[0020] In one embodiment, the above 'halogen anion X-containing salt' may contain one or more selected from nitrogen (N)-containing cations, phosphorus (P)-containing cations (phosphonium-based), and sulfur (S)-containing cations (sulfonium-based) as cations.

[0021] In one embodiment, the above 'halogen anion X-containing salt' may contain a bromide (Br) anion.

[0022] In one embodiment, the above 'halogen anion X-containing salt' may contain a nitrogen (N)-containing cation as a cation.

[0023] In one embodiment, the hexafluorophosphate (PF6) - The step of recovering the liquid containing ) may include the step of introducing a ‘halogen anion X-containing salt’ and a second solvent.

[0024] In one embodiment, the step of recovering the lithium fluoride (LiF) includes the step of introducing a 'fluorine (F) anion-containing salt,' and the 'fluorine (F) anion-containing salt' can be represented as MFn (where M is a cation of n and n is a natural number less than or equal to 3).

[0025] In one embodiment, the hexafluorophosphate (PF6) - A step of recovering a liquid containing ) and a step of recovering the lithium fluoride (LiF); after that, the remaining material in the reactor may include a first solvent and a salt represented by MXn (where M is an n-valent cation, X is a halogen anion, and n is a natural number less than or equal to 3).

[0026] In one aspect, the hexafluorophosphate (PF6) of the present invention -A method for recovering a liquid containing ) and lithium fluoride (LiF) comprises the steps of: introducing a first solvent into an electrolyte containing lithium hexafluorophosphate (LiPF6); and separating a first solvent layer containing lithium hexafluorophosphate (LiPF6); introducing a 'halogen anion X-containing salt' into the separated first solvent layer containing lithium hexafluorophosphate (LiPF6); and hexafluorophosphate (PF6 - The method may include the steps of: separating and recovering a liquid containing ) and separating a first solvent layer containing LiX; and filtering the lithium fluoride (LiF) generated by introducing a 'fluorine (F) anion-containing salt' into the separated first solvent layer containing LiX to recover the lithium fluoride (LiF).

[0027] In one embodiment, a second solvent may be introduced when or after introducing a 'salt containing halogen anion X' into a first solvent layer containing the separated lithium hexafluorophosphate (LiPF6). In this case, the recovered hexafluorophosphate (PF6) - The liquid containing ) may further include a second solvent.

[0028] As another aspect of another aspect, hexafluorophosphate (PF6) according to one aspect of the present invention -A method for recovering a liquid containing ) and lithium fluoride (LiF) comprises the steps of: introducing a first solvent into an electrolyte containing lithium hexafluorophosphate (LiPF6) and then separating a first solvent layer containing lithium hexafluorophosphate (LiPF6); introducing a 'fluorine (F) anion-containing salt' into the separated first solvent layer containing lithium hexafluorophosphate (LiPF6) to generate lithium fluoride (LiF); filtering the generated lithium fluoride (LiF) to recover lithium fluoride (LiF); and introducing a 'halogen anion X-containing salt' into the first solvent layer remaining after the lithium fluoride (LiF) has been filtered, and hexafluorophosphate (PF6 - It may include a step of separating and recovering the liquid containing )

[0029] In one embodiment, a second solvent may be introduced when or after introducing a 'salt containing halogen anion X' into the first solvent layer remaining after the lithium fluoride (LiF) is filtered. In this case, the recovered hexafluorophosphate (PF6) - The liquid containing ) may further include a second solvent.

[0030] In one embodiment, the recovered hexafluorophosphate (PF6) -The liquid containing ) may include one or more selected from ammonium, imidazolium, oxazolium, piperidinium, pyrazinium, pyrazolium, pyridazinium, pyridinium, pyrimidinium, pyrrolidinium, pyrrolinium, pyrrolium, thiazolium, and triazolium.

[0031] One embodiment of the present invention can produce lithium hexafluorophosphate (LiPF6) from the recovered lithium fluoride (LiF).

[0032] One aspect of the present invention is the recovered hexafluorophosphate (PF6) - Lithium hexafluorophosphate (LiPF6) from ) containing liquid and lithium fluoride (LiF) - Can manufacture ).

[0033] One embodiment of the present invention can produce lithium from the recovered lithium fluoride (LiF). Effects of the invention

[0035] As one effect, the present invention, through a simple and economical process, obtains hexafluorophosphate (PF6), a valuable material, from an electrolyte containing lithium hexafluorophosphate (LiPF6). -A method is provided for simultaneously recovering a liquid containing ) and lithium fluoride (LiF) or recovering them continuously.

[0036] In addition, as an effect, lithium hexafluorophosphate (LiPF6) contained in the spent electrolyte - By recovering valuable materials that can be usefully applied using ) as reactants, an eco-friendly and economical waste battery recycling system can be secured in the industrial sector. Specific details for implementing the invention

[0038] Expressions such as "comprising" as used in this specification should be understood as open-ended terms implying the possibility of including other configurations.

[0039] As used herein, "preferably" and "preferably" refer to embodiments of the invention that can provide certain advantages under certain conditions. However, it is not intended to exclude other embodiments from the scope of the invention.

[0040] The numerical ranges used in this specification include lower and upper limits and all values ​​within the range, increments logically derived from the form and width of the defined range, all of which are limited values, and all possible combinations of upper and lower limits of numerical ranges limited in different forms.

[0041] Unless otherwise specifically defined in this specification, values ​​outside the numerical range that may occur due to experimental error or rounding are also included in the defined numerical range.

[0042] Meanwhile, the technical features described below relate to an embodiment that obtains the intended effect of the present invention described above. That is, a method for recovering lithium fluoride according to an embodiment of the present invention can produce the aforementioned effect by including a manufacturing step and technical features according to an embodiment described below.

[0044] The present invention relates to a solution comprising lithium hexafluorophosphate (LiPF6), wherein the hexafluorophosphate (PF6) - This relates to a method for recovering both the liquid containing ) and lithium fluoride (LiF).

[0045] In one embodiment, the present invention relates to a solution comprising lithium hexafluorophosphate (LiPF6) from an electrolyte comprising hexafluorophosphate (PF6). - Liquids containing ) and lithium fluoride (LiF) can be recovered simultaneously or continuously.

[0046] Generally, lithium hexafluorophosphate (LiPF6) is used as the electrolyte salt in the electrolyte used in secondary batteries such as lithium-ion batteries.

[0047] However, when disposing of secondary batteries, safe disposal of toxic lithium hexafluorophosphate (LiPF6) is required.

[0048] The present invention relates to lithium hexafluorophosphate (LiPF6) included in such an electrolyte. -By using ) as a reactant to recover all usefully applicable valuable materials, an eco-friendly and economical waste battery recycling system can be secured in the industrial sector.

[0049] The present invention relates to hexafluorophosphate (PF6) from the above electrolyte - ) The liquid containing it can be recovered.

[0050] In one aspect, the hexafluorophosphate (PF6) - The liquid containing ) is one or more selected from nitrogen (N)-containing cations, phosphorus (P)-containing cations (phosphonium-based), and sulfur (S)-containing cations (sulfonium-based), and hexafluorophosphate (PF6 - It may be a liquid in the form of a salt combined with ).

[0051] As another aspect of the embodiment, the above hexafluorophosphate (PF6) - The liquid containing ) is one or more selected from nitrogen (N)-containing cations, phosphorus (P)-containing cations (phosphonium-based), and sulfur (S)-containing cations (sulfonium-based), and hexafluorophosphate (PF6 - In addition to the salt combined with ), it may further include an organic solvent.

[0052] also, The present invention relates to lithium hexafluorophosphate (LiPF6) included in an electrolyte. - Since it does not decompose into fluorine and forms a salt, it can be utilized more effectively in industry.

[0053] In the present invention, the 'nitrogen (N) containing cation' can be represented, for example, by the following chemical formula.

[0054]

[0055] The above R1 to R4 and r1 to r7 are each independently hydrogen or a hydrocarbon group having 1 to 10 carbon atoms or a heterohydrocarbon group, and L, L1 and L2 may be directly connected, divalent hydrocarbon groups, or divalent heterohydrocarbon groups.

[0056] In the present invention, the term 'hydrocarbon group' includes both cyclic and chain-type hydrocarbon groups, and refers to a combination of one or more saturated hydrocarbons with carbon-carbon single bonds, unsaturated hydrocarbons with double or triple bonds, and aromatic hydrocarbons. Examples include alkyl, alkenyl, alkynyl, aryl, aralkyl, aralkenyl, and alkylaryl groups.

[0057] In the present invention, 'heterohydrocarbon group' refers to a hydrocarbon group containing heteroatoms O, N, P and / or S within the hydrocarbon chain.

[0058] In a more preferred embodiment, the 'nitrogen (N) containing cation' may include one or more selected from ammonium, imidazolium, oxazolium, piperidinium, pyrazinium, pyrazolium, pyridazinium, pyridinium, pyrimidinium, pyrrolidinium, pyrrolinium, pyrrolium, thiazolium, and triazolium.

[0059] In one aspect, the hexafluorophosphate (PF6) - The liquid containing ) may be an ionic liquid.

[0060] Ionic liquids are liquid-phase salts that refer to substances in which cations and anions do not form crystals but exist in a liquid state; unlike the characteristics of conventional salts, they exist as liquids at temperatures below 100°C. Since these ionic liquids have no vapor pressure, a low melting point, a wide electrochemical range, and are environmentally friendly, they can be applied in many fields such as metal electrodeposition, lithium batteries, organic electrosynthesis, sensors, and capacitors. Furthermore, these ionic liquids can be utilized as electrolytes for secondary batteries, allowing for more economical application within the same industrial sector.

[0061] In addition, the present invention can recover lithium fluoride (LiF) from the electrolyte.

[0062] Meanwhile, typically, lithium fluoride (LiF) can be used as a reactant to produce lithium hexafluorophosphate (LiPF6).

[0063] More specifically, lithium hexafluorophosphate (LiPF6) can be prepared by reacting phosphorus pentachloride with lithium fluoride (LiF).

[0064] <Reaction Equation 1>

[0065] PCl5 + LiF + 5HF -> LiPF6+ 5HCl

[0066] In one embodiment, the present invention safely processes the toxic lithium hexafluorophosphate (LiPF6) in the electrolyte of a waste battery by recovering it as lithium fluoride (LiF), and then manufactures lithium hexafluorophosphate (LiPF6) using the recovered lithium fluoride (LiF) to produce the electrolyte again.

[0067] The present invention relates to hexafluorophosphate (PF6). - Liquids containing ) and lithium fluoride (LiF) can be recovered simultaneously or continuously.

[0068] The meaning of 'recovering simultaneously or recovering continuously' above is that both of the above valuable substances are recovered through a continuous reaction proceeding from lithium hexafluorophosphate (LiPF6) in an electrolyte containing lithium hexafluorophosphate (LiPF6) as a reactant.

[0069] The present invention can increase process economic efficiency in that both of the above-mentioned valuable substances can be recovered from lithium hexafluorophosphate (LiPF6).

[0070] For example, the above hexafluorophosphate (PF6 - After the step of recovering the liquid containing ), the step of recovering the lithium fluoride (LiF) may be performed.

[0071] For example, after the step of recovering the lithium fluoride (LiF), the hexafluorophosphate (PF6 - A step of recovering the liquid containing ) can be performed.

[0072] For example, a step of recovering the lithium fluoride (LiF), and the hexafluorophosphate (PF6) - The step of recovering the liquid containing ) can be performed simultaneously through separate recovery processes via a continuous reaction.

[0073] Explains more specific process steps.

[0074] First, a first solvent may be added to the electrolyte containing the lithium hexafluorophosphate (LiPF6), and then a step of separating the first solvent layer containing the lithium hexafluorophosphate (LiPF6) may be performed.

[0075] In one embodiment, the first solvent is hexafluorophosphate (PF6) - It may be a solvent that dissolves LiPF6 without decomposing it and can be separated from the organic solvent layer in the electrolyte, such as EC or DMC.

[0076] The pH of the first solvent is preferably 6 to 8, more preferably 6.5 to 7.5, more preferably neutral, and most preferably, the first solvent may be water. If a strong acid or strong base solvent is used, hexafluorophosphate (PF6) - There may be a problem where ) decomposes into fluorine, etc.

[0077] Generally, in electrolytes used in lithium-ion batteries and the like, lithium hexafluorophosphate (LiPF6) is used as an electrolyte salt. - It contains ) and an organic solvent, and depending on the function, includes additives, and as the organic solvent, carbonate compounds such as dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), propylene carbonate (PC), ethylene carbonate (EC), or ester compounds are included.

[0078] For example, when a first solvent such as water is introduced into the electrolyte, an electrolyte additive such as FEC is dissolved in an organic solvent within the electrolyte, such as a carbonate or ester, and lithium hexafluorophosphate (LiPF6) is dissolved in the first solvent such as water. - ) etc. are dissolved, and the two liquid layers can be separated from each other.

[0080] Next, hexafluorophosphate (PF6) - The steps of recovering a liquid containing ) and recovering lithium fluoride (LiF) can be performed.

[0081] First, hexafluorophosphate (PF6) - Explain the step of recovering the liquid containing ).

[0082] In one embodiment, the hexafluorophosphate (PF6) - The step of recovering the liquid containing ) may include the step of introducing a ‘halogen anion X-containing salt’.

[0083] Meanwhile, the step of introducing the above 'halogen anion X-containing salt' can be performed in the following two embodiments.

[0084] First, as a possible mode, it can be performed by introducing a 'halogen anion X-containing salt' alone.

[0085] In this case, the recovered hexafluorophosphate (PF6) - The liquid containing ) is one or more selected from nitrogen (N)-containing cations, phosphorus (P)-containing cations (phosphonium-based), and sulfur (S)-containing cations (sulfonium-based), and hexafluorophosphate (PF6 - It may be a liquid in the form of a salt combined with ).

[0086] As another possible embodiment, a second solvent may be introduced at or after the introduction of the 'halogen anion X-containing salt'. In this case, the recovered hexafluorophosphate (PF6) - The liquid containing ) may further include a second solvent.

[0087] At this time, the second solvent is the hexafluorophosphate (PF6) - ) liquid containing hexafluorophosphate (PF6 - Without decomposing the above-mentioned first solvent, for example, an organic solvent that does not mix with water, any solvent capable of phase separation can be used without limitation.

[0088] For example, the above-mentioned first solvent may be used, for example, a solvent that has a higher specific gravity than water and separates into layers below the first solvent layer.

[0089] For example, negative polar solvents containing chlorine, such as methylene chloride, dichloroethane, and chloroform, and amine-based solvents such as ethylene amine and ethylene diamine may be used.

[0090] When proceeding in this manner, the first solvent and second solvent layers are phase-separated to obtain hexafluorophosphate (PF6 - A liquid containing ) can be obtained.

[0091] In one embodiment, the halogen anion X included in the 'salt containing halogen anion X' may be one or more selected from chloride anion, bromide anion, or iodide anion, and more preferably may be a bromide anion.

[0092] In one embodiment, the cation included in the above 'halogen anion X-containing salt' may be one or more selected from nitrogen (N)-containing cations, phosphorus (P)-containing cations (phosphonium-based), and sulfur (S)-containing cations (sulfonium-based), but it may be more preferable to use nitrogen (N)-containing cations for a more efficient and economical process.

[0093] The above nitrogen (N)-containing cations, phosphorus (P)-containing cations (phosphonium-based), and sulfur (S)-containing cations (sulfonium-based) are as described above.

[0094] Meanwhile, the above cation is hexafluorophosphate (PF6) recovered as described above. - It can be recovered by being included in the liquid containing it.

[0096] Next, the step of recovering lithium fluoride (LiF) is described.

[0097] In one embodiment, the step of recovering the lithium fluoride (LiF) may include the step of introducing a 'fluorine (F) anion-containing salt'.

[0098] In one embodiment, the above 'fluorine (F) anion-containing salt' can be represented as MFn (where M is an n-valent cation and n is a natural number less than or equal to 3).

[0099] In one embodiment, the above 'fluorine (F) anion-containing salt' may be in the form of a salt of a compound in which the fluorine anion is combined with another element or atomic group (inorganic atomic group or organic atomic group).

[0100] As a more specific example, the above M may be a Na cation, K cation, H cation, Cs cation, Mg cation, Ca cation, Zn cation, KH cation, tetramethylammonium cation, etc.

[0101] As a more specific example, the above 'fluorine (F) anion-containing salt' may be NaF, KF, HF, CsF, MgF2, CaF2, ZnF2, KHF2, tetramethylammonium fluoride, etc.

[0102] Meanwhile, once the above reaction is completed, the method of obtaining solid lithium fluoride (LiF) is not particularly limited.

[0103] In one embodiment, when the above reaction is completed, solid lithium fluoride (LiF) can be obtained by filtering and drying.

[0105] Meanwhile, the above hexafluorophosphate (PF6) - The residual material in the reactor after the step of recovering the liquid containing ) and the step of recovering the lithium fluoride (LiF) may include a first solvent and a salt represented by MXn (where M is an n-valent cation, X is a halogen anion, and n is a natural number less than or equal to 3).

[0106] The first solvent, M and X mentioned above are as described above.

[0107] For example, the above MXn may be KBr, and the above first solvent may be water.

[0108] The present invention relates to hexafluorophosphate (PF6). - After recovering the liquid containing ) and lithium fluoride (LiF), the economic efficiency of the process can be further increased in that the remaining material is environmentally friendly.

[0110] Explains a more specific example of a manufacturing method.

[0111] As an example, hexafluorophosphate (PF6) according to one aspect of the present invention - A method for recovering a liquid containing ) and lithium fluoride (LiF) can be carried out in the following steps.

[0112] First, a first solvent may be added to an electrolyte containing lithium hexafluorophosphate (LiPF6), and then a step of separating the first solvent layer containing lithium hexafluorophosphate (LiPF6) may be performed.

[0113] Next, a 'halogen anion X-containing salt' is added to the first solvent layer containing the separated lithium hexafluorophosphate (LiPF6), and hexafluorophosphate (PF6) - The step of separating and recovering the liquid containing ) and separating the first solvent layer containing LiX can be performed.

[0114] Next, a step of recovering lithium fluoride (LiF) can be performed by filtering the lithium fluoride (LiF) produced by introducing a 'fluorine (F) anion-containing salt' into the first solvent layer containing the separated LiX.

[0116] <Scheme 1>

[0117]

[0119] As another example, a second solvent may be introduced when or after introducing a 'halogen anion X-containing salt' into the first solvent layer containing the separated lithium hexafluorophosphate (LiPF6).

[0120] In this case, the recovered hexafluorophosphate (PF6) - The liquid containing ) may further include a second solvent.

[0122] <Scheme 2>

[0124]

[0126] Meanwhile, the first solvent layer remaining after the lithium fluoride (LiF) is filtered may contain a salt represented by MXn (where M is an n-valent cation, X is a halogen anion, and n is a natural number less than or equal to 3), as described above.

[0128] As another example, the hexafluorophosphate (PF6) of the present invention - A method for recovering a liquid containing ) and lithium fluoride (LiF) can be carried out in the following steps.

[0129] First, a first solvent may be added to an electrolyte containing lithium hexafluorophosphate (LiPF6), and then a step of separating the first solvent layer containing lithium hexafluorophosphate (LiPF6) may be performed.

[0130] Next, a step of producing lithium fluoride (LiF) can be performed by introducing a 'fluorine (F) anion-containing salt' into a first solvent layer containing the separated lithium hexafluorophosphate (LiPF6).

[0131] Next, the lithium fluoride (LiF) generated above can be filtered to recover the lithium fluoride (LiF).

[0132] Simultaneously with or after the recovery of the lithium fluoride (LiF) above, a 'salt containing halogen anion X' is added to the first solvent layer remaining after the lithium fluoride (LiF) is filtered, and hexafluorophosphate (PF6 - A step of separating and recovering the liquid containing ) can be performed.

[0134] <Scheme 3>

[0135]

[0137] As another example, a second solvent may be introduced when or after the ‘halogen anion X-containing salt’ is introduced into the first solvent layer remaining after the lithium fluoride (LiF) is filtered.

[0138] In this case, the recovered hexafluorophosphate (PF6) - The liquid containing ) may further include a second solvent.

[0140] <Scheme 4>

[0141]

[0143] Meanwhile, the first solvent layer remaining after the lithium fluoride (LiF) is filtered may contain M(PF6)n, where M and n are as described above.

[0144] In one embodiment, the hexafluorophosphate (PF6) - The first solvent layer remaining after the liquid containing the ) is separated and recovered may contain a salt represented by MXn (where M is an n-valent cation, X is a halogen anion, and n is a natural number less than or equal to 3), and this is as described above.

[0146] One embodiment of the present invention can produce lithium hexafluorophosphate (LiPF6) from the recovered lithium fluoride (LiF).

[0147] The present invention can provide a recycling system for producing lithium hexafluorophosphate (LiPF6) from lithium fluoride (LiF) recovered from an electrolyte, such as a waste battery, through an eco-friendly and efficient process.

[0148] One aspect of the present invention is the recovered hexafluorophosphate (PF6) - Lithium hexafluorophosphate (LiPF6) from ) containing liquid and lithium fluoride (LiF) - Can manufacture ).

[0149] The present invention relates to hexafluorophosphate (PF6) recovered from electrolytes, such as those from waste batteries, through an environmentally friendly and efficient process. -A recycling system can be provided to produce lithium hexafluorophosphate (LiPF6) again from a liquid containing ) and lithium fluoride (LiF).

[0151] Hereinafter, embodiments of the present invention will be described in more detail.

[0153] <실시예 1>

[0154] After discharging a spent lithium-ion battery (containing 200 ml of electrolyte), the safety valve was removed, and 200 g of water was added through the opening. After leaving it at room temperature for 1 hour, it was immersed in 800 g of water. After 1 hour of immersion, the water layer was separated to obtain 1 kg of water containing 152 g of LiPF6.

[0155] 285g of 1-octyl-4-methylpyridinium bromide was added to the obtained water layer.

[0156] Next, 351g of EA (ethyl acetate) was added and stirred at room temperature for 1 hour.

[0157] By layer separation, 700g of 1-octyl-4-methylpyridinium PF650% EA solution was obtained.

[0158] 58g of KF was added to the aqueous layer and stirred at room temperature for 1 hour.

[0159] The resulting solid was filtered and dried in a 100℃ oven to obtain 25g of LiF.

[0161] <실시예 2>

[0162] After discharging a spent lithium-ion battery (containing 200 ml of electrolyte), the safety valve was removed, and 200 g of water was added through the opening. After leaving it at room temperature for 1 hour, it was immersed in 800 g of water. After 1 hour of immersion, the water layer was separated to obtain 1 kg of water containing 152 g of LiPF6.

[0163] 58g of KF was added and stirred at room temperature for 1 hour.

[0164] The resulting solid was filtered and dried in a 100℃ oven to obtain 25g of LiF.

[0165] 285g of 1-octyl-4-methylpyridinium bromide was added to the aqueous layer.

[0166] Next, 351g of EA (ethyl acetate) was added and stirred at room temperature for 1 hour.

[0167] By layer separation, 700g of 1-octyl-4-methylpyridinium PF6 50% EA solution was obtained.

Claims

Claim 1 From an electrolyte containing lithium hexafluorophosphate (LiPF6), hexafluorophosphate (PF6) - A method for simultaneously recovering or continuously recovering a liquid containing ) and lithium fluoride (LiF), wherein hexafluorophosphate (PF6) - hexafluorophosphate (PF6) comprising: a step of recovering a liquid containing ); and a step of recovering lithium fluoride (LiF). - ) containing liquid and method for recovering lithium fluoride (LiF). Claim 2 In claim 1, the hexafluorophosphate (PF6) - A step of recovering a liquid containing ); and a step of recovering the lithium fluoride (LiF); prior to, a step of adding a first solvent to an electrolyte containing lithium hexafluorophosphate (LiPF6) and then separating a first solvent layer containing lithium hexafluorophosphate (LiPF6); wherein the pH of the first solvent is 6 to 8, hexafluorophosphate (PF6) - ) containing liquid and method for recovering lithium fluoride (LiF). Claim 3 In claim 2, the first solvent is water, hexafluorophosphate (PF6 - ) containing liquid and method for recovering lithium fluoride (LiF). Claim 4 In claim 1, the hexafluorophosphate (PF6) - The step of recovering the liquid containing ) includes the step of introducing a 'halogen anion X-containing salt', wherein the 'halogen anion X-containing salt' is a hexafluorophosphate (PF6) containing one or more selected from nitrogen (N)-containing cations, phosphorus (P)-containing cations (phosphonium-based), and sulfur (S)-containing cations (sulfonium-based) as cations. - ) containing liquid and method for recovering lithium fluoride (LiF). Claim 5 In claim 4, the 'halogen anion X-containing salt' is a hexafluorophosphate (PF6) containing a bromide (Br) anion and a nitrogen (N)-containing cation as a cation. - ) containing liquid and method for recovering lithium fluoride (LiF). Claim 6 In claim 1, the hexafluorophosphate (PF6) - The step of recovering the liquid containing ) includes the step of introducing a 'salt containing halogen anion X' and a second solvent, and hexafluorophosphate (PF6 - ) containing liquid and method for recovering lithium fluoride (LiF). Claim 7 In claim 1, the step of recovering the lithium fluoride (LiF) comprises the step of introducing a 'fluorine (F) anion-containing salt,' wherein the 'fluorine (F) anion-containing salt' is a hexafluorophosphate (PF6) represented by MFn (where M is an n-valent cation and n is a natural number less than or equal to 3). - ) containing liquid and method for recovering lithium fluoride (LiF). Claim 8 In claim 1, the hexafluorophosphate (PF6) - A step of recovering a liquid containing ); and a step of recovering the lithium fluoride (LiF); whereby, the remaining material in the reactor is a hexafluorophosphate (PF6) comprising a first solvent and a salt represented by MXn (where M is an n-valent cation, X is a halogen anion, and n is a natural number less than or equal to 3). - ) containing liquid and method for recovering lithium fluoride (LiF). Claim 9 In claim 1, the step of adding a first solvent to an electrolyte containing lithium hexafluorophosphate (LiPF6) and then separating a first solvent layer containing lithium hexafluorophosphate (LiPF6); adding a 'halogen anion X-containing salt' to the separated first solvent layer containing lithium hexafluorophosphate (LiPF6), and hexafluorophosphate (PF6) - A step of separating and recovering a liquid containing ) and separating a first solvent layer containing LiX; and a step of filtering the lithium fluoride (LiF) generated by introducing a 'fluorine (F) anion-containing salt' into the separated first solvent layer containing LiX to recover lithium fluoride (LiF); comprising hexafluorophosphate (PF6 - ) containing liquid and method for recovering lithium fluoride (LiF). Claim 10 In claim 9, a second solvent is added when or after adding a 'halogen anion X-containing salt' to a first solvent layer containing the separated lithium hexafluorophosphate (LiPF6), and in this case, the recovered hexafluorophosphate (PF6 - The liquid containing ) further comprises a second solvent, hexafluorophosphate (PF6 - ) containing liquid and method for recovering lithium fluoride (LiF). Claim 11 In claim 1, the method comprises the steps of: adding a first solvent to an electrolyte containing lithium hexafluorophosphate (LiPF6), and then separating a first solvent layer containing lithium hexafluorophosphate (LiPF6); adding a 'fluorine (F) anion-containing salt' to the separated first solvent layer containing lithium hexafluorophosphate (LiPF6) to produce lithium fluoride (LiF); filtering the produced lithium fluoride (LiF) to recover lithium fluoride (LiF); and adding a 'halogen anion X-containing salt' to the first solvent layer remaining after the lithium fluoride (LiF) has been filtered, and hexafluorophosphate (PF6 - hexafluorophosphate (PF6) comprising the step of separating and recovering a liquid containing ) - ) containing liquid and method for recovering lithium fluoride (LiF). Claim 12 In claim 1, when or after introducing a 'salt containing halogen anion X' into the first solvent layer remaining after the lithium fluoride (LiF) is filtered, a second solvent is introduced, and in this case, the recovered hexafluorophosphate (PF6) - The liquid containing ) further comprises a second solvent, hexafluorophosphate (PF6 - ) containing liquid and method for recovering lithium fluoride (LiF). Claim 13 In claim 1, the recovered hexafluorophosphate (PF6) - The liquid containing ) comprises one or more selected from ammonium, imidazolium, oxazolium, piperidinium, pyrazinium, pyrazolium, pyridazinium, pyridinium, pyrimidinium, pyrrolidinium, pyrrolinium, pyrrolium, thiazolium, and triazolium, hexafluorophosphate (PF6 - ) containing liquid and method for recovering lithium fluoride (LiF). Claim 14 A method for producing lithium hexafluorophosphate (LiPF6) from lithium fluoride (LiF) recovered according to claim 1. Claim 15 Hexafluorophosphate (PF6) recovered according to claim 1 - Lithium hexafluorophosphate (LiPF6) from ) containing liquid and lithium fluoride (LiF) - Method of manufacturing ).

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