Method for producing lithium salt and system for producing lithium salt

Abstract

To provide a method for producing a lithium salt from raw material water including LiCl.SOLUTION: A method for producing a lithium salt includes an adsorption step, a cleansing step, and a desorption step. In the adsorption step, a first electrode 1 and a second electrode 2 including λ-MnO2 are immersed in raw material water 21 including LiCl. By applying a first voltage between the first electrode 1 and the second electrode 2, Li+ is adsorbed on the first electrode 1. In the cleansing step, the first electrode 1 subjected to the adsorption step is cleansed with a cleansing solution 22. In the desorption step, the first electrode 1 and the third electrode 3 that have undergone the cleansing step are immersed in water 23 comprising anions. A second voltage is applied between the first electrode 1 and the third electrode 3. As a result, a lithium salt is produced from Li+ desorbed from the first electrode 1 and the anion. The first electrode 1 is a belt, and the first electrode 1 moves along the length direction thereof during the adsorption step, the cleansing step, and the desorption step.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing a lithium salt and a system for producing a lithium salt. [Background technology]

[0002] Lithium-ion secondary batteries are used in industrial products such as electric vehicles (EVs), hybrid electric vehicles (HEVs), and portable electronic devices (e.g., smartphones). Lithium compounds (lithium salts) such as Li2CO3 and LiOH are used as raw materials for the positive electrodes of lithium-ion secondary batteries.

[0003] Conventional methods for producing lithium salts include the flotation method, which uses ore as a raw material, and the brine method, which uses brine as a raw material. The brine method is superior to the flotation method in terms of its low production costs.

[0004] For example, the conventional method for producing Li2CO3 based on the brine method includes an evaporation step in which brine is evaporated in the sun to obtain a concentrated aqueous solution of LiCl, a concentration step in which impurities such as Na, K, Mg, and Ca are removed from the aqueous solution using chemicals, and a concentration step in which the Li2CO3 or CO2 is added to the aqueous solution to remove the LiCl. + and a carbonation step of carbonating the mixture.

[0005] For example, in the conventional method for producing LiOH based on the brine method, in addition to the carbonation step described above, the addition of hydroxide (e.g., Ca(OH)) to an aqueous solution of Li2CO3 results in the formation of Li in the aqueous solution. + Alternatively, in addition to the evaporation and concentration steps described above, a conventional method for producing LiOH involves electrolyzing an aqueous solution of LiCl to hydrate Li in the aqueous solution. + The method further comprises a hydroxylation step of hydroxylating

[0006] With the recent rapid increase in demand for electric vehicles, a shortage of lithium salt supply and a rise in the price of lithium salts are expected. However, as described above, conventional methods for producing lithium salts based on the brine method require the cost of a concentration step (e.g., the cost of chemicals). In other words, the conventional production cost of lithium salts cannot be said to be sufficiently low. Therefore, a method for producing lithium salts that does not require a concentration step using chemicals is desired.

[0007] For example, Patent Document 1 discloses a method for recovering lithium, which includes an adsorption step of electrochemically adsorbing lithium in an aqueous solution onto a conductive manganese oxide (working electrode), and a desorption step of electrochemically desorbing the lithium in the working electrode from the working electrode after the adsorption step. The lithium recovery method described in Patent Document 1 allows lithium to be recovered at low cost without performing a concentration step using a chemical agent. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 6-88277 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of one aspect of the present disclosure is to provide a method for producing a lithium salt from raw material water containing LiCl, and a system for producing a lithium salt. [Means for solving the problem]

[0010] For example, one aspect of the present disclosure relates to a method for producing a lithium salt according to any one of the following [1] to [7], and a system (apparatus) for producing a lithium salt according to any one of the following [8] to

[12] .

[0011] [1] The method includes an adsorption step, a washing step, and a desorption step, In the adsorption step, a first electrode containing λ-MnO and a second electrode serving as a counter electrode of the first electrode are immersed in raw water containing LiCl; A first voltage is applied between the first electrode and the second electrode in the raw water, and the potential of the first electrode is made lower than the potential of the second electrode, thereby detecting Li in the raw water. + is adsorbed onto the first electrode, In the washing step, the first electrode that has undergone the adsorption step is washed with a washing solution containing water, In the desorption step, the first electrode that has been subjected to the cleaning step and a third electrode that is a counter electrode of the first electrode are immersed in water containing anions, A second voltage is applied between the first electrode and the third electrode in the water, and the potential of the first electrode is made higher than the potential of the third electrode, thereby + is desorbed from the first electrode, Li desorbed from the first electrode + and the anion in the water to form a lithium salt, the first electrode is a belt; During the adsorption step, the first electrode moves through the raw water along a longitudinal direction of the first electrode; During the cleaning step, the first electrode is moved through the cleaning solution along the length direction; During the desorption step, the first electrode moves along the length direction through the water containing the anions. Method for producing lithium salts.

[0012] [2] The first electrode is an endless belt, The first electrode is circulated along the length direction, thereby repeating the adsorption step, the washing step, and the desorption step. [1] A method for producing the lithium salt according to the present invention.

[0013] [3] The first electrode is supplied into the raw water from an electrode roll consisting of a rolled first electrode, After the first electrode is removed from the raw water, the cleaning solution, or the water containing the anions, the first electrode is wound up again. [1] A method for producing the lithium salt according to the present invention.

[0014] [4] The first electrode is supplied into the cleaning solution from an electrode roll formed by winding up the first electrode, After the first electrode is removed from the cleaning solution or the water containing the anions, the first electrode is rewound. The method for producing the lithium salt according to [1] or [3].

[0015] [5] The first electrode is supplied from an electrode roll formed of the wound first electrode into the water containing the anions, After the first electrode is removed from the water, the first electrode is rewound. The method for producing the lithium salt according to [1], [3] or [4].

[0016] [6] A plurality of the second electrodes are immersed in the raw water; a surface of each of the second electrodes faces a surface of the first electrode via the raw water; The method for producing the lithium salt according to any one of [1] to [5].

[0017] [7] A plurality of the third electrodes are immersed in the water containing the anions; a surface of each of the plurality of third electrodes faces a surface of the first electrode via the water; The method for producing the lithium salt according to any one of [1] to [6].

[0018] [8] A lithium salt production system used in the lithium salt production method according to [1], a first electrolytic bath, a cleaning bath, and a second electrolytic bath; the first electrode, the second electrode, and the third electrode; Power supply and a conveying device including a plurality of guide rolls; Including, the raw water, the first electrode, and the second electrode are placed in the first electrolytic cell; the cleaning solution and the first electrode that has been subjected to the adsorption step are placed in the cleaning tank; the water containing the anions, the first electrode that has been subjected to the washing step, and the third electrode are placed in the second electrolytic cell; the power supply applies a first voltage between the first electrode and the second electrode and a second voltage between the first electrode and the third electrode; a surface of the first electrode contacts a surface of each of a plurality of guide rolls; the transport device moves the first electrode; Lithium salt production system.

[0019] [9] The first electrode is an endless belt, the conveying device circulates the first electrode along the length direction; The first electrode is circulated along the length direction, thereby repeating the adsorption step, the washing step, and the desorption step. [8] The lithium salt production system according to [8].

[0020]

[10] The conveying device an electrode supplying device that supplies the first electrode from an electrode roll formed of the wound first electrode to the raw water, the cleaning solution, or the water containing the anion; an electrode winding device that rewinds the first electrode after the first electrode is removed from the raw water, the cleaning solution, or the water containing the anions; Further comprising: [8] A system for producing a lithium salt as described in [8].

[0021]

[11] A plurality of the second electrodes, A plurality of the second electrodes are immersed in the raw water; a surface of each of the second electrodes faces a surface of the first electrode via the raw water; The system for producing a lithium salt according to any one of [8] to

[10] .

[0022]

[12] A plurality of the third electrodes, a plurality of the third electrodes are immersed in the water containing the anions; a surface of each of the plurality of third electrodes faces a surface of the first electrode via the water; The system for producing a lithium salt according to any one of [8] to

[11] . [Effects of the Invention]

[0023] According to the present disclosure, there are provided a method for producing a lithium salt from raw water containing LiCl, and a system for producing a lithium salt. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic cross-sectional view of a specific example (production system 100A) of a lithium salt production system according to the present disclosure. [Figure 2] FIG. 2 is a schematic cross-sectional view of a specific example (production system 100B1) of a lithium salt production system according to the present disclosure. [Figure 3] FIG. 3 is a schematic cross-sectional view of a specific example (production system 100B2) of a lithium salt production system according to the present disclosure. [Figure 4] FIG. 4 is a schematic cross-sectional view of a specific example (production system 100B3) of a lithium salt production system according to the present disclosure. [Figure 5] FIG. 5 is a schematic cross-sectional view of a specific example (production system 100B4) of a lithium salt production system according to the present disclosure. [Figure 6]FIG. 6 is a schematic cross-sectional view of a specific example of the first electrolytic cell 31 or the second electrolytic cell 32 in the lithium salt production system according to the present disclosure. [Figure 7] FIG. 7 is a schematic cross-sectional view of a specific example of the first electrolytic cell 31 or the second electrolytic cell 32 in the lithium salt production system according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, preferred embodiments of the present disclosure will be described with reference to the drawings. In the drawings, like elements are designated by like reference numerals. The present disclosure is not limited to the following embodiments.

[0026] (Outline of lithium salt manufacturing method and lithium salt manufacturing system) The lithium salt production system (production apparatus) according to this embodiment may be any one of production system 100A in FIG. 1, production system 100B1 in FIG. 2, production system 100B2 in FIG. 3, production system 100B3 in FIG. 4, or production system 100B4 in FIG. 5.

[0027] Each manufacturing system shown in each of Figures 1 to 5 includes a first electrolytic bath 31, a cleaning bath 33, a second electrolytic bath 32, a first electrode 1, a second electrode 2, a third electrode 3, a power supply 10, and a transport device 5. Figures 6 and 7 show modifications of the internal structure of the first electrolytic bath 31 or the second electrolytic bath 32 shown in each of Figures 1 to 5. Each of the first electrolytic bath 31, the cleaning bath 33, and the second electrolytic bath 32 may be made of a chemically inert material.

[0028] The first electrode 1 contains λ-MnO2 (spinel-type manganese dioxide). The first electrode 1 is a belt extending in one direction. The belt may also be called a band or a strip. The cross section of the first electrode 1 shown in each of FIGS. 1 to 7 is parallel to the length direction of the first electrode 1 (the direction in which the first electrode 1 extends) and perpendicular to the surface (main surface) of the first electrode 1. Therefore, the orientation of the first electrode 1 (the moving direction of the first electrode 1) shown in each of FIGS. 1 to 7 corresponds to the length direction of the first electrode 1.

[0029] The first electrode 1 is moved by the conveying device 5 along the length direction of the first electrode 1 (the direction in which the first electrode 1 extends). In other words, the first electrode 1 is long in the moving direction of the first electrode 1 and short in the direction perpendicular to the moving direction of the first electrode 1. The conveying device 5 includes a plurality of guide rolls 5b. For example, each guide roll 5b is cylindrical, and each guide roll 5b freely rotates about the central axis of the guide roll 5b (cylinder). The cross section (circle) of each guide roll 5b shown in each of FIGS. 1 to 7 is perpendicular to the central axis of each guide roll 5b. Each guide roll 5b may extend in a direction perpendicular to the length direction (moving direction) of the first electrode 1 (and in a direction parallel to the surface of the first electrode 1). The length of each guide roll 5b may be equal to or greater than the width of the first electrode 1 (the width of the first electrode 1 in the direction perpendicular to the length direction of the first electrode 1). The surface of the first electrode 1 is in contact with each surface of the plurality of guide rolls 5b, and the first electrode 1 moves while passing through each guide roll 5b. The position of each guide roll 5b may be fixed. Depending on the arrangement of each of the multiple guide rolls 5b, the moving direction of the first electrode 1 may be freely adjusted. Each guide roll 5b may be made of a chemically inactive material.

[0030] Raw water 21 containing LiCl and the second electrode 2 are placed in a first electrolytic cell 31. The second electrode 2 may be partially or entirely immersed in the raw water 21. One or more guide rolls 5b may be disposed in the first electrolytic cell 31 and may be immersed in the raw water 21.

[0031] A cleaning liquid 22 containing water is placed in the cleaning tank 33. One or more guide rolls 5b may be placed in the cleaning tank 33 and immersed in the cleaning liquid 22.

[0032] Water 23 containing anions and the third electrode 3 are placed in a second electrolytic cell 32. The third electrode 3 may be partially or entirely immersed in the water 23. One or more guide rolls 5b may be disposed in the second electrolytic cell 32 and may be immersed in the water 23.

[0033] The first electrode 1 moves in raw water 21 along the length direction of the first electrode 1. After the first electrode 1 moves in raw water 21, the first electrode 1 moves in cleaning liquid 22 along the length direction of the first electrode 1. After the first electrode 1 moves in cleaning liquid 22, the first electrode 1 moves in water 23 containing anions along the length direction of the first electrode 1.

[0034] The production system is used in the method for producing a lithium salt according to the present embodiment. For example, the lithium salt produced according to the present embodiment may be at least one compound selected from the group consisting of LiOH (lithium hydroxide), LiCl (lithium chloride), and LiCO (lithium carbonate), or may be at least one compound selected from the group consisting of LiOH (lithium hydroxide) and LiCl (lithium chloride).

[0035] The method for producing the lithium salt includes an adsorption step, a washing step, and a desorption step.

[0036] During the adsorption process, the first electrode 1 is immersed in the raw water 21 and moves in the raw water 21 along the length of the first electrode 1. During the process of the first electrode 1 moving in the raw water 21, the potential difference between the first electrode 1 and the second electrode 2 causes the Li + (Lithium ions) are adsorbed onto the first electrode 1. During the washing step, the first electrode 1 that has undergone the adsorption step is immersed in a washing liquid 22 and moves through the washing liquid 22 along the length direction of the first electrode 1. In the process in which the first electrode 1 moves through the washing liquid 22, impurities derived from the raw water 21 are removed from the first electrode 1 by the washing liquid 22. The first electrode 1 that has undergone the cleaning process is immersed in water 23 during the desorption process, and moves through the water 23 along the length of the first electrode 1. During the process of the first electrode 1 moving through the water 23, the potential difference between the first electrode 1 and the third electrode 3 causes Li + is desorbed from the first electrode 1. Li desorbed from the first electrode 1 + and anions in water 23 to form lithium salts.

[0037] In a conventional batch-type adsorption process in which the first electrode 1 is fixed in the raw water 21, replacing the first electrode 1 after the adsorption process is completed requires time and effort. In contrast, in this embodiment, the flow-type adsorption process can be carried out continuously by adjusting the length and movement speed of the first electrode 1 (belt). That is, in this embodiment, the adsorption process can be easily continued, the time and frequency of interruptions to the adsorption process for replacing the first electrode 1 can be easily reduced, and the amount of work required to replace the first electrode 1 can be easily reduced. In a conventional batch-type cleaning process in which the first electrode 1 is fixed in the cleaning solution 22, work and time are required to replace the first electrode 1 after the cleaning process is completed. On the other hand, in this embodiment, the flow-type cleaning process can be carried out continuously by adjusting the length and movement speed of the first electrode 1 (belt). That is, in this embodiment, it is easy to continue the cleaning process, the time and frequency of interruptions to the cleaning process for replacing the first electrode 1 are easy to reduce, and the amount of work required to replace the first electrode 1 is easy to reduce. In a conventional batch-type desorption process in which the first electrode 1 is fixed in water 23, work and time are required to replace the first electrode 1 after the desorption process is completed. On the other hand, in this embodiment, the flow-type desorption process can be carried out continuously by adjusting the length and movement speed of the moving first electrode 1. That is, in this embodiment, it is easy to continue the desorption process, the time and frequency of interruptions to the desorption process for replacing the first electrode 1 are easy to reduce, and the amount of work required to replace the first electrode 1 is easy to reduce. For the above reasons, according to this embodiment, the productivity of lithium salts is likely to be improved, and the manufacturing costs of lithium salts are likely to be reduced.

[0038] As shown in FIG. 1 , the first electrode 1 may be an endless belt. The endless belt may be referred to as a closed belt or a belt that loops along the length. The conveying device 5 circulates the first electrode 1 (endless belt) along the length of the first electrode 1. For example, the first electrode 1 (endless belt) is driven by a driving device 5a (e.g., a motor) of the conveying device 5 and circulates within the manufacturing system 100A while passing through multiple guide rolls 5b. By circulating the first electrode 1 (endless belt) along the length, the adsorption step, the cleaning step, and the desorption step are simultaneously performed, and the adsorption step, the cleaning step, and the desorption step are repeated. As a result, compared to a manufacturing method in which the adsorption step, the cleaning step, and the desorption step are performed sequentially and individually, the time required to produce the lithium salt is shortened, the productivity of the lithium salt is improved, and the manufacturing cost of the lithium salt is reduced. The time for which the first electrode 1 is immersed in each of the raw water 21, the cleaning solution 22, and the anion-containing water 23 may be adjusted by adjusting the speed of the first electrode 1 (endless belt) circulating within the production system 100A. When the speed of the first electrode 1 (endless belt) circulating within the production system 100A is constant, the time for which the first electrode 1 is immersed in the raw water 21 (the duration of the adsorption process per unit length of the first electrode 1) may be adjusted by adjusting the length of the portion of the first electrode 1 immersed in the raw water 21. The time for which the first electrode 1 is immersed in the cleaning solution 22 (the duration of the cleaning process per unit length of the first electrode 1) may be adjusted by adjusting the length of the portion of the first electrode 1 immersed in the cleaning solution 22. The time for which the first electrode 1 is immersed in the water 23 containing anions (the duration of the desorption process per unit length of the first electrode 1) may be adjusted by adjusting the length of the portion of the first electrode 1 immersed in the water 23.

[0039] As shown in FIGS. 2 to 5, the transport device 5 may include an electrode supply device 5c and an electrode winding device 5d. The electrode supply device 5c supplies the first electrode 1 from an electrode roll 1r consisting of a wound first electrode 1 into raw water 21, a cleaning solution 22, or anion-containing water 23. The electrode winding device 5d rewinds the first electrode 1 after the first electrode 1 is removed from the raw water 21, the cleaning solution 22, or the anion-containing water 23. In other words, the electrode winding device 5d winds the first electrode 1 to form the electrode roll 1r. For example, the electrode supply device 5c and the electrode winding device 5d may each be a motor having a rotation shaft (e.g., a cylinder) around which the first electrode 1 is wound.

[0040] The manufacturing system 100B1 shown in FIG. 2 has three pairs of electrode supplying devices 5c and electrode winding devices 5d, and one pair of electrode supplying devices 5c and electrode winding devices 5d is used in each of the adsorption step, the washing step, and the desorption step. In the case of the manufacturing system 100B1, the first electrode 1 is supplied from the electrode roll 1r into the raw water 21 by the electrode supply device 5c. The first electrode 1 removed from the raw water 21 is not supplied to the cleaning solution 22, but is rewound by the electrode winding device 5d. In other words, the first electrode 1 that has undergone the adsorption step is wound before the cleaning step to form the electrode roll 1r. The electrode supply device 5c and the electrode winding device 5d may adjust the speed at which the first electrode 1 moves in the adsorption step. In other words, the time it takes for the entire first electrode 1 to pass through the raw water 21 (the duration of the adsorption step) may be adjusted by the electrode supply device 5c and the electrode winding device 5d. In the case of the manufacturing system 100B1, the first electrode 1 that has passed through the raw water 21 (adsorption step) is supplied from the electrode roll 1r into the cleaning solution 22 by the electrode supply device 5c. The first electrode 1 removed from the cleaning solution 22 is not supplied to the anion-containing water 23, but is rewound by the electrode winding device 5d. In other words, the first electrode 1 that has passed through the cleaning step is wound up before the desorption step to form the electrode roll 1r. The electrode supply device 5c and the electrode winding device 5d may adjust the speed at which the first electrode 1 moves in the cleaning step. In other words, the time it takes for the entire first electrode 1 to pass through the cleaning solution 22 (the duration of the cleaning step) may be adjusted by the electrode supply device 5c and the electrode winding device 5d. In the case of the manufacturing system 100B1, the first electrode 1 that has been subjected to the cleaning solution 22 (cleaning step) is supplied from the electrode roll 1r by the electrode supply device 5c into water 23 containing anions. The first electrode 1 removed from the water 23 is rewound by the electrode winding device 5d. In other words, the first electrode 1 that has been subjected to the desorption step is wound up to form the electrode roll 1r. The electrode supply device 5c and the electrode winding device 5d may adjust the speed at which the first electrode 1 moves in the desorption step. In other words, the time it takes for the entire first electrode 1 to pass through the water 23 (the duration of the desorption step) may be adjusted by the electrode supply device 5c and the electrode winding device 5d. In the manufacturing system 100B1, by using a pair of electrode supply device 5c and electrode winding device 5d in each of the adsorption process, cleaning process, and desorption process, the speed of the first electrode 1 in each of the adsorption process, cleaning process, and desorption process can be adjusted individually.

[0041] The manufacturing system 100B2 shown in FIG. 3 has two pairs of electrode supply devices 5c and electrode winding devices 5d, and one pair of electrode supply devices 5c and electrode winding devices 5d is used in the adsorption process and the cleaning process, and another pair of electrode supply devices 5c and electrode winding devices 5d is used in the desorption process. In the case of the manufacturing system 100B2, the first electrode 1 is supplied from the electrode roll 1r into the raw water 21 by the electrode supply device 5c. The first electrode 1 removed from the raw water 21 is supplied to the cleaning solution 22 without being wound up. The first electrode 1 removed from the cleaning solution 22 is re-wound by the electrode winding device 5d without being supplied to the anion-containing water 23. In other words, the first electrode 1 that has undergone the cleaning step is wound up before the detachment step to form the electrode roll 1r. In the case of the manufacturing system 100B2, the first electrode 1 that has been subjected to the cleaning solution 22 (cleaning step) is supplied from the electrode roll 1r by the electrode supply device 5c into water 23 containing anions. The first electrode 1 that has been removed from the water 23 is rewound by the electrode winding device 5d. In other words, the first electrode 1 that has been subjected to the desorption step is wound up to form the electrode roll 1r.

[0042] The manufacturing system 100B3 shown in FIG. 4 has two pairs of electrode supply devices 5c and electrode winding devices 5d, and one pair of electrode supply devices 5c and electrode winding devices 5d is used in the adsorption process, and another pair of electrode supply devices 5c and electrode winding devices 5d is used in the cleaning process and the desorption process. In the case of the manufacturing system 100B3, the first electrode 1 is supplied from the electrode roll 1r into the raw water 21 by the electrode supply device 5c. The first electrode 1 taken out of the raw water 21 is not supplied to the cleaning liquid 22, but is rewound by the electrode winding device 5d. That is, the first electrode 1 that has undergone the adsorption step is wound before the cleaning step, and the electrode roll 1r is formed. In the case of the manufacturing system 100B3, the first electrode 1 that has been subjected to the raw material water 21 (adsorption step) is supplied from the electrode roll 1r into the cleaning solution 22 by the electrode supply device 5c. The first electrode 1 that has been removed from the cleaning solution 22 is supplied to the water 23 containing anions without being wound up. The first electrode 1 that has been removed from the water 23 is wound up again by the electrode winding device 5d. In other words, the first electrode 1 that has been subjected to the desorption step is wound up to form the electrode roll 1r.

[0043] 2 to 4, the adsorption step, washing step, and desorption step can be performed simultaneously by using multiple electrode rolls 1r and multiple pairs of electrode supply devices 5c and electrode winding devices 5d. As a result, compared to a production method in which the adsorption step, washing step, and desorption step are performed sequentially and individually, the time required to produce the lithium salt is shortened, the productivity of the lithium salt is improved, and the production cost of the lithium salt is reduced.

[0044] A manufacturing system 100B4 shown in FIG. 5 has a pair of an electrode supplying device 5c and an electrode winding device 5d, and the pair of the electrode supplying device 5c and the electrode winding device 5d are used in the adsorption step, the cleaning step, and the desorption step. In the case of the manufacturing system 100B4, the first electrode 1 is supplied from the electrode roll 1r into raw water 21 by an electrode supply device 5c. The first electrode 1 removed from the raw water 21 is supplied to a cleaning solution 22 without being wound up. The first electrode 1 removed from the cleaning solution 22 is supplied to water 23 containing anions without being wound up. The first electrode 1 removed from the water 23 is wound up again by an electrode winding device 5d. In other words, the first electrode 1 that has undergone the detachment step is wound up to form an electrode roll 1r.

[0045] 2 to 5, an electrode roll 1r made of a first electrode 1 that has been exposed to anion-containing water 23 (desorption step) may be reused for the adsorption step. The method for producing a lithium salt may further include a separate washing step in which the first electrode 1 that has been exposed to anion-containing water 23 (desorption step) is washed with a washing liquid 22 before the first electrode 1 that has been exposed to anion-containing water 23 (desorption step) is reused for the adsorption step. To perform this separate washing step, the lithium salt production system may further include a separate washing tank containing the washing liquid 22.

[0046] The cross section of the second electrode 2 shown in each of Figures 1 to 7 is perpendicular to the surface (main surface) of the second electrode 2. In each of Figures 1 to 7, the surface of the first electrode 1 faces the surface of the second electrode 2 in raw water 21. The cross section of the third electrode 3 shown in each of Figures 1 to 7 is perpendicular to the surface (main surface) of the third electrode 3. In each of Figures 1 to 7, the surface of the first electrode 1 faces the surface of the third electrode 3 in water 23.

[0047] As shown in FIG. 6 , the production system may include a plurality of second electrodes 2 contained in a first electrolytic bath 31. The plurality of second electrodes 2 may be immersed in raw water 21. The surface of each of the plurality of second electrodes 2 may face one or both surfaces of the first electrode 1 through the raw water 21. For example, the first electrode 1 may be bent at a plurality of locations where it contacts the guide roll 5b, and the second electrodes 2 may be arranged between the zigzag bent first electrodes 1. In other words, the first electrode 1 may meander in the first electrolytic bath 31, so that the first electrode 1 and the plurality of second electrodes 2 are arranged alternately in the raw water 21. By using a plurality of second electrodes 2, the total area of the second electrodes 2 is increased, and the amount of Li to the first electrode 1 is reduced. + Since the adsorption of the hydroxybenzoates is promoted, the time required for the adsorption step is shortened.

[0048] As shown in FIG. 6 , the production system may include a plurality of third electrodes 3 contained in a second electrolytic bath 32. The plurality of third electrodes 3 may be immersed in water 23 containing anions. The surface of each of the plurality of third electrodes 3 may face one or both surfaces of the first electrode 1 through the water 23 containing anions. For example, the first electrode 1 may be bent at a plurality of locations where it contacts the guide roll 5b, and the third electrode 3 may be disposed between the first electrodes 1 bent in a zigzag pattern. In other words, the first electrode 1 may meander in the second electrolytic bath 32, so that the first electrode 1 and the plurality of third electrodes 3 are alternately disposed in the water 23. By using a plurality of third electrodes 3, the total area of the third electrodes 3 increases, and Li from the first electrode 1 is reduced. + This promotes desorption, thereby shortening the time required for the desorption process.

[0049] As shown in FIG. 7 , the first electrolytic cell 31 may be long horizontally, and the surface of the second electrode 2 immersed in the raw water 21 may be parallel to the bottom of the first electrolytic cell 31. In other words, the surface of the second electrode 2 immersed in the raw water 21 may be parallel to the horizontal direction. Furthermore, the second electrode 2 may extend along the bottom of the first electrolytic cell 31 and face a portion of the first electrode 1 that is parallel to the bottom of the first electrolytic cell 31 (a horizontal portion) across the raw water 21. This configuration of the first electrolytic cell 31 can extend the time that the first electrode 1 resides in the first electrolytic cell 31. For example, only one second electrode 2 may be disposed either above or below the portion of the first electrode 1 that is parallel to the bottom of the first electrolytic cell 31. Alternatively, one of the pair of second electrodes 2 may be disposed above the portion of the first electrode 1 that is parallel to the bottom of the first electrolytic cell 31, and the other of the pair of second electrodes 2 may be disposed below the portion of the first electrode 1 that is parallel to the bottom of the first electrolytic cell 31. The second electrolytic bath 32 may also be horizontally elongated. The surface of the third electrode 3 immersed in the anion-containing water 23 may also be parallel to the bottom surface of the second electrolytic bath 32. In other words, the surface of the third electrode 3 immersed in the water 23 may be parallel to the horizontal direction. Furthermore, the third electrode 3 may extend along the bottom surface of the second electrolytic bath 32 and face a portion of the first electrode 1 that is parallel to the bottom surface of the second electrolytic bath 32 (a horizontal portion) across the water 23. This configuration of the second electrolytic bath 32 can extend the time that the first electrode 1 resides in the second electrolytic bath 32. For example, only one third electrode 3 may be disposed either above or below the portion of the first electrode 1 that is parallel to the bottom surface of the second electrolytic bath 32. Alternatively, one of the pair of third electrodes 3 may be disposed above the portion of the first electrode 1 that is parallel to the bottom surface of the second electrolytic bath 32, and the other of the pair of third electrodes 3 may be disposed below the portion of the first electrode 1 that is parallel to the bottom surface of the second electrolytic bath 32. 7, when the first electrode 1 is disposed between a pair of second electrodes 2 in the first electrolytic bath 31, the first electrode 1 may also be disposed between a pair of third electrodes 3 in the second electrolytic bath 32. In this case, Li+ Adsorption and desorption are likely to occur. When only one second electrode 2 is disposed above the portion of the first electrode 1 that is parallel to the bottom surface of the first electrolytic cell 31, only one third electrode 3 may be disposed above the portion of the first electrode 1 that is parallel to the bottom surface of the second electrolytic cell 32. In this case, the upper surface of the first electrode 1 is + Adsorption and desorption are likely to occur. When only one second electrode 2 is disposed below the portion of the first electrode 1 that is parallel to the bottom surface of the first electrolytic cell 31, only one third electrode 3 may be disposed below the portion of the first electrode 1 that is parallel to the bottom surface of the second electrolytic cell 32. In this case, the lower surface of the first electrode 1 is + Adsorption and desorption are likely to occur. 6, in the horizontally long first electrolytic cell 31 shown in Fig. 7, the first electrode 1 may be bent at multiple locations where it contacts the guide roll 5b, and multiple second electrodes 2 parallel to the bottom surface of the first electrolytic cell 31 may be arranged between the zigzag bent first electrodes 1. In other words, the first electrode 1 may snake within the horizontally long first electrolytic cell 31, so that the first electrode 1 and multiple second electrodes 2 are arranged alternately in the raw water 21. As in the case of the horizontally long first electrolytic cell 31, in the horizontally long second electrolytic cell 32, the first electrode 1 may be bent at multiple locations where it contacts the guide roll 5b, and multiple third electrodes 3 parallel to the bottom surface of the second electrolytic cell 32 may be arranged between the zigzag bent first electrodes 1. In other words, the first electrode 1 may snake within the horizontally long second electrolytic cell 32, so that the first electrode 1 and multiple third electrodes 3 are arranged alternately in the water 23 containing anions.

[0050] Although not shown, cleaning tank 33 may also be horizontally long, and the surface of first electrode 1 immersed in cleaning liquid 22 may be parallel to the bottom surface of horizontally long cleaning tank 33. In other words, the surface of first electrode 1 immersed in cleaning liquid 22 may be parallel to the horizontal direction.

[0051] The lithium salt production system is not limited to the production systems shown in each of Figures 1 to 5. The production system may include a plurality of first electrolytic baths 31, a plurality of cleaning baths 33, or a plurality of second electrolytic baths 32. For example, a first electrolytic cell 31, another first electrolytic cell 31, a cleaning cell 33, another cleaning cell 33, a second electrolytic cell 32, and another second electrolytic cell 32 may be arranged in series in this order. For example, a first electrolytic bath 31, a cleaning bath 33, another first electrolytic bath 31, another cleaning bath 33, and a second electrolytic bath 32 may be arranged in series in this order. For example, a first electrolytic bath 31, a cleaning bath 33, a second electrolytic bath 32, another cleaning bath 33, and another second electrolytic bath 32 may be arranged in series in this order. For example, a first electrolytic bath 31, a cleaning bath 33 (first cleaning bath), another first electrolytic bath 31, another cleaning bath 33 (second cleaning bath), a second electrolytic bath 32, another cleaning bath 33 (third cleaning bath), and another second electrolytic bath 32 may be arranged in series in this order.

[0052] (Details of the adsorption process) In the adsorption step, the second electrode 2 is the counter electrode of the first electrode 1. The first electrode 1 and the second electrode 2 are electrically connected to a power source 10 and are spaced apart from each other in the raw water 21. In the adsorption step, the first electrode 1 is the cathode (negative electrode), and the second electrode 2 is the anode (positive electrode). In the adsorption step, the power source 10 applies a first voltage between the first electrode 1 and the second electrode 2 in the raw water 21, and reduces the potential of the first electrode 1 to be lower than the potential of the second electrode 2. As a result, Li in the raw water 21 + is adsorbed onto the λ-MnO contained in the first electrode 1. In other words, lithium in the raw water 21 can be concentrated at the first electrode 1 by an adsorption process without carrying out a conventional concentration process using a chemical.

[0053] The first voltage applied between the first electrode 1 and the second electrode 2 in the adsorption step is not particularly limited. For example, the first voltage may be equal to or lower than a voltage at which no oxygen is generated at the first electrode 1. For example, the first voltage (potential of the first electrode 1) based on a standard hydrogen electrode (SHE) in the adsorption step may be equal to or higher than 0 V vs. SHE and equal to or lower than 1.23 V vs. SHE.

[0054] 1 to 5, each production system may include a diode 4 for a first electrolytic bath 31. In the first electrolytic bath 31, a first electrode 1 may be electrically connected to a power source 10 via the diode 4. In the first electrolytic bath 31, an anode of the diode 4 may be electrically connected to the first electrode 1, and a cathode of the diode 4 may be electrically connected to a negative electrode of the power source 10. The rectifying action of the diode 4 in the first electrolytic bath 31 suppresses reverse current flow during the adsorption process. As shown in FIGS. 1 and 5, when the first electrode 1 is continuous without interruption from the adsorption step to the desorption step, it is preferable to provide a diode 4 for the first electrolytic cell 31. On the other hand, as shown in FIGS. 2 to 4, when the first electrode 1 is wound up between the adsorption step and the cleaning step, or between the cleaning step and the desorption step (when the first electrode 1 is interrupted between the adsorption step and the desorption step), a reverse current is unlikely to occur, and therefore the diode 4 for the first electrolytic cell 31 does not need to be provided.

[0055] Li in raw water 21 + The reaction of adsorption onto the first electrode 1 (λ-MnO2) may be represented by the following chemical formula 1A. That is, the reaction occurring at the first electrode 1 (cathode) during the adsorption process may be represented by the following chemical formula 1A. 2λ-MnO2+Li + +e - → LiMn2O4(1A)

[0056] The reaction occurring at the second electrode 2 (anode) during the adsorption process may be represented by the following chemical formula 2: That is, O2 (oxygen) may be produced at the second electrode 2 during the adsorption process. (3 / 2)H2O → (1 / 4)O2 + H3O + +e - (2)

[0057] For example, the raw water 21 containing LiCl may contain at least one of brine from a salt lake and seawater. The raw water 21 may consist only of brine from a salt lake. The raw water 21 may consist only of seawater. The raw water 21 may contain both brine from a salt lake and seawater. The content (concentration) of LiCl in the raw water 21 is not limited. For example, the content (concentration) of LiCl in the raw water 21 may be 0.1 mass ppm or more and 10 mass % or less in terms of Li. For example, the pH of the raw water 21 containing LiCl may be 7 or more.

[0058] (Details of the cleaning process) Impurities in the raw materials for the positive electrode of a lithium ion secondary battery deteriorate the performance of the lithium ion secondary battery, so lithium salts with reduced impurity content are desired. According to this embodiment, impurities derived from the raw water 21 are removed from the first electrode 1 by the washing step. As a result, high-purity lithium salts can be obtained in the desorption step following the washing step. For example, impurities derived from the raw water 21 include Na + (sodium ion), K + (potassium ion), Ca 2+ (Calcium ion), and Mg 2+ (magnesium ions). When a lithium salt other than LiCl is produced, Cl derived from the raw water 21 may be used. - (chloride ions) are also removed as impurities from the first electrode 1 by the washing step. In this embodiment, the "high-purity lithium salt" refers to the Li salt in the first electrode 1 that has been subjected to a washing process. +The term "high purity lithium salt" refers to a lithium salt formed from a first electrode 1 having a reduced content of impurities other than lithium, such as alkali metals and alkaline earth metals. In other words, "high purity lithium salt" refers to a lithium salt produced using a first electrode 1 from which impurities have been removed by a washing process. "High purity" does not necessarily mean that the absolute value of the purity of the lithium salt is higher than the absolute value of the purity of lithium salts obtained by conventional production methods. The purity of the lithium salt produced by the lithium salt production method according to this embodiment is not particularly limited. For example, the purity of the lithium salt produced by the lithium salt production method according to this embodiment may be 99% by mass or more and 100% by mass or less.

[0059] For example, the cleaning liquid 22 may be pure water. When LiOH (sodium hydroxide) is produced as the lithium salt, the cleaning liquid 22 may be an aqueous solution of LiOH. When LiCl is produced as the lithium salt, the cleaning liquid 22 may be an aqueous solution of LiCl. The cleaning liquid 22 may be neutral or basic (alkaline). For example, the pH of the cleaning liquid 22 may be 7.0 or more and 14.0 or less.

[0060] (Details of the desorption process) In the desorption step, the third electrode 3 is the counter electrode of the first electrode 1. The first electrode 1 and the third electrode 3 are electrically connected to a power source 10 and are spaced apart in water 23 containing anions. In the desorption step, the first electrode 1 is the anode (positive electrode), and the third electrode 3 is the cathode (negative electrode). In the desorption step, the power source 10 applies a second voltage between the first electrode 1 and the third electrode 3 in the water 23, and raises the potential of the first electrode 1 above the potential of the third electrode 3. As a result, Li + is desorbed from the first electrode 1. Li desorbed from the first electrode 1 + and anions in the water 23, a lithium salt is generated in the water 23. + As a result of the desorption of O, H2 (hydrogen) may be produced at the third electrode 3. During the desorption process, O2 may be produced at the first electrode 1.

[0061] The second voltage applied between the first electrode 1 and the third electrode 3 in the desorption step is not particularly limited. For example, the second voltage (potential of the first electrode 1) relative to the standard hydrogen electrode in the desorption step may be 0 V vs. SHE or more and 1.23 V vs. SHE or less.

[0062] 1 to 5, each manufacturing system may include a diode 4 for a second electrolytic bath 32. In the second electrolytic bath 32, the first electrode 1 may be electrically connected to a power source 10 via the diode 4. In the second electrolytic bath 32, the anode of the diode 4 may be electrically connected to a positive electrode of the power source 10, and the cathode of the diode 4 may be electrically connected to the first electrode 1. The rectifying action of the diode 4 in the second electrolytic bath 32 suppresses reverse current flow during the desorption process. As shown in FIGS. 1 and 5, when the first electrode 1 is continuous without interruption from the adsorption step to the desorption step, it is preferable to provide a diode 4 for the second electrolytic cell 32. On the other hand, as shown in FIGS. 2 to 4, when the first electrode 1 is wound up between the adsorption step and the cleaning step, or between the cleaning step and the desorption step (when the first electrode 1 is interrupted between the adsorption step and the desorption step), a reverse current is unlikely to occur, and therefore the diode 4 for the second electrolytic cell 32 does not need to be provided.

[0063] For example, water containing anions 23 is OH - (hydroxide ion), Cl - (chloride ions), CO3 2- (carbonate ion), or HCO3 - The water may be water containing hydrogen carbonate ions.

[0064] Li + The reaction of desorbing from the first electrode 1 may be represented by the following chemical formula 1B. That is, the reaction occurring at the first electrode 1 (anode) during the desorption process may be represented by the following chemical formula 1B. LiMn2O4 → 2λ-MnO2+Li + +e - (1B)

[0065] The pH of the anion-containing water 23 may be adjusted appropriately depending on the composition of the target lithium salt, and is not particularly limited. For example, if the anion-containing water 23 is neutral or alkaline, the reaction occurring at the third electrode 3 (cathode) during the desorption process may be represented by Equation 3A below. H2O+e - → (1 / 2)H2+OH - (3A) For example, if the anion-containing water 23 is acidic, the reaction occurring at the third electrode 3 (cathode) during the desorption process may be represented by Equation 3B below. H3O + +e - → (1 / 2)H2+H2O (3B)

[0066] For example, the anion-containing water 23 is pure water (OH as an anion). - When the anion-containing water 23 is pure water, the anion (OH - ) containing water 23 is neutral. For example, water containing anions 23 is LiOH 、 The anion-containing water 23 may be an aqueous solution of at least one hydroxide selected from the group consisting of NaOH, KOH, Ca(OH)2, and Mg(OH)2. When the anion-containing water 23 is an aqueous solution of the above hydroxides, the anion (OH - The anion-containing water 23 may be alkaline. Because LiOH is readily available, the anion-containing water 23 may be an aqueous solution containing only LiOH as the hydroxide. For example, anion-containing water 23 may contain LiCl 、 It may be an aqueous solution of at least one chloride selected from the group consisting of NaCl, KCl, CaCl2, and MgCl2. When the anion-containing water 23 is an aqueous solution of the chloride, the anion (Cl - The anion-containing water 23 may be an aqueous solution containing only LiCl as a chloride.

[0067] For example, the anions in the water 23 used in the desorption step are OH -The lithium salt generated during the desorption step may be LiOH. + The reaction of anions in water to form a lithium salt may be represented by the following chemical formula 4A: Li + +OH - → LiOH (4A) LiOH is suitable as a raw material for high-nickel cathodes (cathode with a high nickel content). Lithium-ion secondary batteries using high-nickel cathodes have a high energy density and are therefore used in many electric vehicles. - The content (concentration) of OH in water 23 used in the desorption step is not limited. - The content (concentration) of -7 The concentration may be mol / L or more, as long as it is below the concentration at which oxygen is not generated from the first electrode.

[0068] For example, the anions in the water 23 used in the desorption step are Cl - The lithium salt generated during the desorption step may be LiCl. + The reaction of anions in water to form a lithium salt may be represented by the following chemical formula 4B: Li + +Cl - → LiCl (4B) Cl in water 23 used in the desorption step - The content (concentration) of Cl in the water 23 used in the desorption step is not limited. - The content (concentration) of Cl in the water 23 used in the desorption step may be 4.8 mol / L or more. - The content (concentration) of may be 13.4 mol / L or less.

[0069] When LiOH is produced, CO3 is added as water containing anions. 2- Water containing CO3 is not recommended. 2-is easily decomposed by the first electrode 1 during the desorption process to produce CO2 and O2. 2- decomposes during the desorption process, the Li desorbed from the first electrode 1 + and OH derived from water itself - Therefore, the water 23 used in the desorption step is CO3 2- The CO3 in the water 23 used in the desorption step may 2- The content (concentration) of should be 8.2 mol / L or less.

[0070] Water 23 containing the lithium salt produced in the desorption step is recovered from the second electrolytic cell 32. Lithium salt with a reduced content of impurities is recovered from the water 23 containing the lithium salt. For example, the lithium salt may be recovered from the water 23 by drying the water 23 recovered from the second electrolytic cell 32. When the water 23 recovered from the second electrolytic cell 32 contains both LiOH and LiCl, one or both of LiOH and LiCl may be recovered from the water 23 by crystallization utilizing the difference in solubility between LiOH and LiCl.

[0071] (Power supply details) The method for generating the electricity supplied by the power source 10 to the manufacturing system is not particularly limited. For example, the electricity supplied by the power source 10 to the manufacturing system may be generated by thermal power generation using fossil fuels or nuclear power generation. The power source 10 may include a renewable energy power generation device that implements at least one power generation method selected from the group consisting of solar power generation, wind power generation, geothermal power generation, hydroelectric power generation, and tidal power generation. The power source 10 including a renewable energy power generation device generates electricity derived from renewable energy. The renewable energy power generation device does not emit CO2 during power generation.

[0072] Instead of the renewable energy power generation system described above, the power source 10 may include at least one hydrogen power generation system selected from a hydrogen gas turbine and a fuel cell. If H2 is produced at the third electrode 3 during the desorption process, the hydrogen power generation system may generate electricity from some or all of the H2 produced during the desorption process. The power source 10 may include both a hydrogen gas turbine and a fuel cell as a hydrogen power generation system. A hydrogen gas turbine is a gas turbine that generates electricity using H2 as fuel instead of conventional natural gas. A fuel cell produces electricity and H2O through a chemical reaction between H2 and O2 (e.g., oxygen in the atmosphere). A hydrogen power generation system does not emit CO2 during power generation. A part or all of the H2 produced in the desorption step may be recovered from the second electrolytic cell 32 and supplied to the hydrogen power generation system. A part or all of the H2 produced in the desorption step may be sold as a product without being supplied to the hydrogen power generation system.

[0073] Power source 10 may include both renewable energy power plants and hydrogen power plants. In this disclosure, "green power" refers to one or both of electricity derived from renewable energy sources and electricity derived from H2 produced in the desorption process. The power supply 10 may further include a storage battery. The storage battery may store electricity derived from renewable energy (electricity obtained from a renewable energy power generation system). The storage battery may store electricity obtained from H2 produced in the desorption process (electricity obtained from a hydrogen power generation system). The type of storage battery is not limited. For example, the storage battery may be a lithium-ion secondary battery.

[0074] One or both of the power consumed in the adsorption process and the power consumed in the desorption process may be the "green power" described above. That is, at least one of the first voltage and the second voltage may be generated by at least one of power derived from renewable energy and power obtained from H2. The green power may be supplied to each process directly from a renewable energy power generation system or a hydrogen power generation system, or may be supplied to each process from a storage battery. For example, in the adsorption process, the power source 10 may apply the first voltage between the first electrode 1 and the second electrode 2 using green power. For example, in the desorption process, the power source 10 may apply the second voltage between the first electrode 1 and the third electrode 3 using green power. Only one of the power consumed in the adsorption process and the power consumed in the desorption process may be green power. Both the power consumed in the adsorption process and the power consumed in the desorption process may be green power. Both the power derived from renewable energy and the power obtained from H2 are green power that does not involve CO2 emissions due to the combustion of fossil fuels. Therefore, by performing at least one of the adsorption step and the desorption step using green electricity, it is possible to reduce CO2 emissions associated with the production of lithium salts using electricity.

[0075] The second voltage required for the desorption step is higher than the first voltage required for the adsorption step. In other words, the desorption step is more likely to consume power than the adsorption step. Therefore, it is preferable that the second voltage be generated by green power, since this makes it easier to reduce CO2 emissions associated with the production of lithium salts using electricity. In other words, it is preferable that green power be preferentially consumed in the desorption step between the adsorption step and the desorption step.

[0076] When the power source 10 (hydrogen power generation device) generates green electricity using some or all of the H2 produced together with the lithium salt in the desorption process, the cost of electricity per unit mass (unit: kg) of the produced lithium salt decreases. As a result, lithium salt can be produced at a lower cost than with conventional production methods that do not use green electricity (electricity obtained from H2).

[0077] Even if a part or all of the H2 produced together with the lithium salt in the desorption process is not used for generating green electricity but is sold as a product, the total cost of electricity required to produce the lithium salt and H2 is allocated to the cost of the lithium salt and the cost of H2. As a result, H2 can be produced at a lower cost than conventional H2 production methods that do not involve the production of lithium salts.

[0078] In regions where a supply source of raw water 21 containing LiCl is located, sufficient electricity is not always available due to geographical constraints. For example, salt lakes located in South America, such as Chile, Bolivia, and Argentina, are located at high altitudes, and it is not easy to supply electricity in high-altitude regions. For example, it is also not easy to supply electricity around salt lakes located in desert regions of Australia. However, by selecting a power generation method suitable for the geographical conditions (e.g., altitude or hours of sunlight) of the region where the supply source of raw water 21 is located from the group consisting of solar power generation, wind power generation, geothermal power generation, hydroelectric power generation, and tidal power generation, it becomes possible to produce lithium salts using sufficient electricity in the region where the supply source of raw water 21 is located.

[0079] (Details of each electrode) The first electrode 1 may contain other components in addition to λ-MnO2. For example, the first electrode 1 may be a mixture containing, in addition to λ-MnO2, at least one of a conductive material (conductive additive) and a binder (adhesive). For example, the conductive material may be at least one of carbon black and an inert metal. For example, the binder may be a resin (e.g., polyvinylidene fluoride). The first electrode 1 may include a layer containing λ-MnO2 and a current collector on which the layer containing λ-MnO2 is laminated. Both the front and back surfaces of the current collector may be covered with a layer containing λ-MnO2. For example, the layer containing λ-MnO2 may be the above-mentioned mixture. For example, the current collector may be a chemically inert metal.

[0080] The second electrode 2 may be made of a material that is not easily corroded by the raw water 21 containing LiCl. The third electrode 3 may be made of a material that is not easily corroded by the water 23 containing anions. For example, at least one of the second electrode 2 and the third electrode 3 may contain at least one conductor selected from the group consisting of platinum, platinum black, gold, glassy carbon, diamond, aluminum, iron, nickel, and stainless steel (SUS). Each of the second electrode 2 and the third electrode 3 may be made of a conductor alone. Because H2 is easily generated in the desorption step, the third electrode 3 preferably contains platinum. The composition of the second electrode 2 may be the same as the composition of the third electrode 3. The composition of the second electrode 2 may be different from the composition of the third electrode 3. The second electrode 2 used in the adsorption step may be used as the third electrode 3 in the desorption step. For example, the second electrode 2 and the third electrode 3 may each be in the shape of a plate.

[0081] The present disclosure is not necessarily limited to the above-described embodiments. Various modifications of the present disclosure are possible without departing from the spirit of the present disclosure, and these modifications are also included in the present disclosure. [Industrial Applicability]

[0082] For example, the method for producing a lithium salt according to one aspect of the present disclosure may be implemented as a method for producing a raw material for the positive electrode of a lithium ion secondary battery. [Explanation of symbols]

[0083] 1...first electrode, 1r...electrode roll, 2...second electrode, 3...third electrode, 4...diode, 5...conveying device, 5a...driving device, 5b...guide roll, 5c...electrode supply device, 5d...electrode winding device, 10...power source, 21...raw material water containing LiCl, 22...cleaning solution, 23...water containing anion, 31...first electrolytic cell, 32...second electrolytic cell, 33...cleaning tank, 100A, 100B1, 100B2, 100B3, 100B4...lithium salt production system.

Claims

1. The method includes an adsorption step, a cleaning step, and a desorption step, In the adsorption step, λ-MnO ２ a first electrode containing the compound and a second electrode that is a counter electrode of the first electrode, are immersed in raw water containing LiCl; A first voltage is applied between the first electrode and the second electrode in the raw water, and the potential of the first electrode is made lower than the potential of the second electrode, thereby ＋ is adsorbed onto the first electrode, In the washing step, the first electrode that has undergone the adsorption step is washed with a washing solution containing water, In the desorption step, the first electrode that has been subjected to the cleaning step and a third electrode that is a counter electrode of the first electrode are immersed in water containing anions, A second voltage is applied between the first electrode and the third electrode in the water, and the potential of the first electrode is made higher than the potential of the third electrode, thereby ＋ is desorbed from the first electrode, Li desorbed from the first electrode ＋ and the anion in the water to form a lithium salt, the first electrode is a belt; During the adsorption step, the first electrode moves through the raw water along a longitudinal direction of the first electrode; During the cleaning step, the first electrode is moved through the cleaning solution along the length direction; During the desorption step, the first electrode moves along the length direction through the water containing the anions. Method for producing lithium salts.

2. the first electrode is an endless belt, The first electrode is circulated along the length direction, thereby repeating the adsorption step, the washing step, and the desorption step. The method for producing the lithium salt according to claim 1 .

3. the first electrode is supplied into the raw water from an electrode roll formed by winding up the first electrode; After the first electrode is removed from the raw water, the cleaning solution, or the water containing the anions, the first electrode is wound up again. The method for producing the lithium salt according to claim 1 .

4. the first electrode is supplied into the cleaning solution from an electrode roll formed by winding up the first electrode; After the first electrode is removed from the cleaning solution or the water containing the anions, the first electrode is rewound. The method for producing the lithium salt according to claim 1 .

5. the first electrode is supplied from an electrode roll formed of the wound first electrode into the water containing the anions, After the first electrode is removed from the water, the first electrode is rewound. The method for producing the lithium salt according to claim 1 .

6. A plurality of the second electrodes are immersed in the raw water; a surface of each of the second electrodes faces a surface of the first electrode via the raw water; The method for producing the lithium salt according to claim 1 .

7. a plurality of the third electrodes are immersed in the water containing the anions; a surface of each of the plurality of third electrodes faces a surface of the first electrode via the water; The method for producing the lithium salt according to claim 1 .

8. A lithium salt production system used in the lithium salt production method according to claim 1, a first electrolytic bath, a cleaning bath, and a second electrolytic bath; the first electrode, the second electrode, and the third electrode; Power supply and a conveying device including a plurality of guide rolls; Equipped with the raw water and the second electrode are placed in the first electrolytic cell; The cleaning solution is contained in the cleaning tank, the water containing the anions and the third electrode are placed in the second electrolytic cell; the power supply applies a first voltage between the first electrode and the second electrode and a second voltage between the first electrode and the third electrode; a surface of the first electrode contacts a surface of each of a plurality of guide rolls; the conveying device moves the first electrode along a length direction of the first electrode; Lithium salt production system.

9. the first electrode is an endless belt, the conveying device circulates the first electrode along the length direction; The first electrode is circulated along the length direction, thereby repeating the adsorption step, the washing step, and the desorption step. The system for producing a lithium salt according to claim 8 .

10. The conveying device an electrode supplying device that supplies the first electrode from an electrode roll formed of the wound first electrode to the raw water, the cleaning solution, or the water containing the anion; an electrode winding device that rewinds the first electrode after the first electrode is removed from the raw water, the cleaning solution, or the water containing the anions; Further comprising: The system for producing a lithium salt according to claim 8.

11. A plurality of the second electrodes are provided, A plurality of the second electrodes are immersed in the raw water; a surface of each of the second electrodes faces a surface of the first electrode via the raw water; The system for producing a lithium salt according to claim 8.

12. A plurality of the third electrodes are provided, a plurality of the third electrodes are immersed in the water containing the anions; a surface of each of the plurality of third electrodes faces a surface of the first electrode via the water; The system for producing a lithium salt according to claim 8.

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