Lithium desorption device

Abstract

The present invention suppresses deterioration of an adsorbent so that lithium is appropriately desorbed. The present invention has a positive electrode, a negative electrode, an adsorption layer which is provided between the positive electrode and the negative electrode and to which an adsorbent adsorbing lithium ions is supplied, a substance layer which is provided between the adsorption layer and the negative electrode and to which a substance to be electrolyzed is supplied, a binding layer provided between the adsorption layer and the substance layer, a first permeation membrane which is provided between the adsorption layer and the binding layer and which allows lithium ions separated from the adsorbent in the adsorption layer to pass through, and a second permeation membrane which is provided between the substance layer and the binding layer and which allows anions ionized from the substance layer in the substance layer to pass through, wherein in the binding layer, lithium ions that have passed through the first permeation membrane and anions that have passed through the second permeation membrane are supplied; and a lithium compound in which a lithium ion and an anion are bound is produced.

Description

Lithium Desorption Device

[0001] The present disclosure relates to a lithium desorption device.

[0002] Techniques for recovering resources contained in seawater from seawater have been disclosed. For example, Patent Document 1 discloses a technique in which lithium in seawater is adsorbed by an adsorbent, and the adsorbent is passed through a weak acid solution to desorb the lithium from the adsorbent as ions. It also discloses a technique for recovering lithium by injecting carbon dioxide gas discharged from a power plant into the seawater to bubble it and recovering it as lithium carbonate.

[0003] Japanese Patent Application Publication No. 1-313323

[0004] It is known that weak acid treatment deteriorates adsorbents, and there is room for improvement in increasing the reusability of adsorbents in order to properly recover target components contained in seawater.

[0005] The present disclosure has been made in view of the above, and has an object to provide a lithium desorption device capable of appropriately desorbing lithium contained in seawater.

[0006] The lithium desorption device according to the present disclosure includes a positive electrode, a negative electrode, an adsorption layer provided between the positive electrode and the negative electrode and supplied with an adsorbent having adsorbed lithium ions, a material layer provided between the adsorption layer and the negative electrode and supplied with a material to be electrolyzed, a binding layer provided between the adsorption layer and the material layer, a first permeable membrane provided between the adsorption layer and the binding layer and allowing permeation of lithium ions separated from the adsorbent in the adsorption layer, and a second permeable membrane provided between the material layer and the binding layer and allowing permeation of anions ionized from the material layer in the material layer, wherein the lithium ions that have permeated the first permeable membrane and the anions that have permeated the second permeable membrane are supplied to the binding layer, and a lithium compound in which the lithium ions and the anions are bound to each other is produced.

[0007] According to the present disclosure, lithium can be appropriately released.

[0008] Fig. 1 is a schematic diagram showing the overall configuration of a target component recovery system according to a first embodiment. Fig. 2 is a schematic diagram showing the flow of target components contained in seawater. Fig. 3 is a schematic diagram showing the structure of a lithium desorption device. Fig. 4 is a schematic diagram showing the structure of a lithium desorption device. Fig. 5 is a schematic diagram showing the overall configuration of a target component recovery system according to a second embodiment.

[0009] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes configurations that combine the various embodiments. Furthermore, the components in the embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially identical, and those that are within the so-called equivalent range. Furthermore, the components in the embodiments described below can be variously omitted, substituted, or modified without departing from the spirit of the present invention.

[0010] [First embodiment] A target component recovery system 1 according to this embodiment will be described with reference to Figures 1 and 2. Figure 1 is a schematic diagram showing the overall configuration of the target component recovery system according to the first embodiment. Figure 2 is a schematic diagram showing the flow of target components contained in seawater.

[0011] <Target Component Recovery System> As shown in FIGS. 1 and 2 , the target component recovery system 1 includes a plant 100, a water intake facility 10, an adsorbent storage tank 20, a mixing tank 26, an adsorbent separator 28, an adsorption device 30, a wastewater treatment device 43, a lithium desorption device 40, a target component recovery device 50, and a control unit 90. The target component recovery system 1 recovers a target component (resource) contained in a solution by performing a predetermined process. Here, the solution is preferably seawater, concentrated wastewater from a seawater desalination facility that produces freshwater from seawater, or brine from a salt lake. Examples of the target component include lithium, uranium, and magnesium, but are not limited to these target components as long as they can be recovered using the system of the present disclosure. In the following description, the solution is seawater and the target component is lithium. That is, the target component recovery system according to the present disclosure is a system for recovering lithium contained in seawater.

[0012] (Plant) The plant 100 is a facility that produces resources and materials necessary for industrial activities. The plant 100 preferably uses seawater taken in from a water intake facility 10 (described later). The plant 100 also discharges a heated medium, a waste heat medium, generated during operation. The waste heat medium may be any medium. For example, if the plant 100 is equipped with a steam turbine, the waste heat medium may be steam after driving the steam turbine. For example, if the plant 100 is equipped with a boiler, the waste heat medium may be steam after use in the boiler. The plant 100 may also discharge the waste heat medium from multiple locations. The plant 100 may be any facility that uses seawater and discharges a waste heat medium, for example, a nuclear power plant, a thermal power plant, a chemical plant, or the like. In this embodiment, the plant 100 will be described using a nuclear power plant as an example. In this embodiment, the plant 100 is preferably an operating plant.

[0013] (Nuclear Power Plant) Here, an overview of a nuclear power plant (nuclear power plant) will be described. The nuclear power plant has, for example, a pressurized water reactor (PWR). The nuclear power plant generates, for example, electricity using heat generated in the pressurized reactor. The nuclear power plant uses light water as a reactor coolant and a neutron moderator to produce high-temperature, high-pressure water that does not boil throughout the entire reactor core. This high-temperature, high-pressure water (primary coolant) is sent to a steam generator to generate steam through heat exchange. This steam (secondary coolant) is then sent to a turbine generator to generate electricity. Here, the secondary coolant is converted into steam in the steam generator by the heat of the high-temperature, high-pressure primary coolant from the reactor. After driving the steam turbine, the secondary coolant is cooled with seawater in a condenser 101 to become condensed water, and the condensed water is returned to the steam generator by a condensate pump. The nuclear facility may be a nuclear facility using a boiling water reactor (BWR).

[0014] After the secondary coolant drives the steam turbine to generate electricity, the condenser 101 cools the secondary coolant with seawater from the sea S to generate condensate. The steam, which is the secondary coolant, passes through a steam flow path 101a and is sent to the condenser 101. The condenser 101 supplies the generated condensate to the steam generator through a condensate flow path 101b.

[0015] (Water Intake Facility) The water intake facility 10 is used in the plant 100 to take in seawater. The water intake facility 10 takes in seawater from a water intake target adjacent to the plant 100 (nuclear facility), which is the sea S in this embodiment, supplies the acquired seawater to a condenser 101, and discharges seawater discharged from the condenser 101 to the adsorption device 30. The water intake facility 10 includes a water intake channel 12, a screen 14, a water discharge channel 16, and a pump P.

[0016] The intake channel 12 is a channel having one end connected to the sea S and the other end connected to the condenser 101. Seawater from the sea S flows into the intake channel 12 and is supplied to the condenser 101. A certain range of the intake channel 12 from the side connected to the condenser 101 becomes a pipeline. The portion of the intake channel 12 that connects to the sea S may be a channel with an open top, for example.

[0017] The screen 14 is provided midway along the intake channel 12. The screen 14 is a mesh member. The screen 14 removes foreign matter contained in the seawater. The seawater passes through the screen 14 and is driven to the condenser 101 by a pump P provided further ahead.

[0018] One end of the discharge channel 16 is connected to the condenser 101, and the other end is connected to the adsorption device 30. A portion of the discharge channel 16 on the side connected to the condenser 101 is, for example, hollow and cylindrical, and the seawater that has cooled the secondary coolant in the condenser 101 flows toward the adsorption device 30. In other words, the discharge channel 16 can be said to be a pipe that connects between the water intake facility 10 and the adsorption device 30.

[0019] The pump P is configured to cause seawater taken in from the intake channel 12 to flow into the condenser 101. The pump P is connected to a drive unit (not shown). The pump P operates when the drive unit is driven.

[0020] (Adsorbent Storage Tank) The adsorbent storage tank 20 stores an adsorbent that adsorbs target components in a solution (seawater). The adsorbent storage tank 20 supplies the adsorbent to the mixing tank 26. The adsorbent storage tank 20 supplies the stored adsorbent to the mixing tank 26 under the control of the control unit 90. For example, the adsorbent storage tank 20 is provided with a pipe connected to the mixing tank 26 and a valve attached to the pipe, and the control unit 90 controls the opening and closing of the valve to control the supply of the adsorbent in the adsorbent storage tank 20 to the mixing tank 26. In this embodiment, the adsorbent storage tank 20 stores a mixture of the adsorbent and a liquid. That is, the adsorbent storage tank 20 stores the adsorbent in a state where the adsorbent is contained in the liquid. The liquid here may be any liquid, such as water.

[0021] Here, the adsorbent will be described. The adsorbent is a substance that adsorbs a target component (resource) contained in a solution (for example, seawater). The adsorbent adsorbs, for example, a target component contained in seawater in the form of ions. The adsorbent may be, for example, in powder form. The adsorbent may be any substance that can adsorb a target component. For example, when the target component to be recovered is lithium, manganese oxide may be used as the adsorbent. In this case, for example, the adsorbent is preferably manganese oxide with openings formed therein large enough for lithium ions to enter so that the lithium ions can be captured. For example, the adsorbent may be a spinel-type manganese oxide (λ-MnO ２ ) and iron phosphate (FePO ４ ) is preferable. For example, if the target component is uranium, an adsorbent (mole) other than manganese oxide may be used. Furthermore, multiple types of adsorbents may be used. However, the adsorbent is not limited to manganese oxide specifically for recovering lithium or a mole for recovering uranium, and may be an adsorbent having a structure suitable for the resource to be recovered. For example, the adsorbent may be general manganese oxide instead of manganese oxide specifically for recovering lithium. This makes it possible to adsorb resources other than lithium with manganese oxide.

[0022] (Adsorption Device) The adsorption device 30 is a device that adds an adsorbent to a solution (seawater) to generate an adsorption liquid containing the solution and the adsorbent.

[0023] The adsorption device 30 is supplied with seawater as a solution taken in by the water intake facility 10 via the water discharge channel 16. That is, the seawater taken in by the water intake facility 10 is heat exchanged in the condenser 101 and then flows into the adsorption device 30 through the water discharge channel 16. The adsorption device 30 is also supplied with an adsorbent from the adsorbent storage tank 20. As a result, the adsorbent is added to the seawater in the adsorption device 30, and an adsorption solution containing seawater and the adsorbent is generated. Note that the adsorption device 30 may be provided with, for example, an agitator that agitates the seawater and the adsorbent.

[0024] It is preferable to store the seawater with the adsorbent added (the adsorbent-added seawater) in the adsorption device 30 for a predetermined period (e.g., several days to approximately 14 days). By storing the seawater for a predetermined period, the target components can be appropriately adsorbed by the adsorbent. When storing seawater for a predetermined period in this manner, while the seawater is being stored in one adsorption device 30, seawater can be taken into another adsorption device 30 and an adsorbent can be added. That is, the target component recovery system 1 can efficiently perform the recovery process by taking seawater into another adsorption device 30 while taking seawater into another adsorption device 30. Therefore, it is preferable that the target component recovery system 1 be provided with multiple adsorption devices 30. More specifically, after taking seawater into an adsorption device 30 and adding an adsorbent, the supply of seawater to that adsorption device 30 may be stopped while taking seawater into another adsorption device 30. By performing this process for multiple adsorption devices 30, the target components can be efficiently recovered.

[0025] (Lithium Desorption Device) One end of the lithium desorption device 40 is connected to the adsorption device 30, and the other end is connected to the target component recovery device 50. The lithium desorption device 40 is supplied with the adsorption solution produced by the adsorption device 30 from the adsorption device 30.

[0026] 3 is a schematic diagram showing the structure of a lithium desorption device. The lithium desorption device 40 converts lithium ions (Li ＋The lithium desorption device 40 generates a lithium compound from the desorbed lithium ions. The electrolysis and generation of the lithium compound will be described later. The lithium desorption device 40 includes a power supply unit 410 and a main body 420.

[0027] The power supply unit 410 includes a wiring 411 and a power supply 412. The wiring 411 connects a positive electrode 421 and a negative electrode 422 of the main body 420. The power supply 412 is provided midway along the wiring 411. The positive side of the power supply 412 is connected to the positive electrode 421 of the main body 420, and the negative side is connected to the negative electrode 422 of the main body 420. When a current flows through the power supply unit 410, the power supply unit 410 divides the voltage applied to the power supply 412 and applies it to the main body 420.

[0028] The body 420 includes a positive electrode 421 , a negative electrode 422 , an adsorption layer 424 , a material layer 428 , a binding layer 440 , a first permeable membrane 450 , and a second permeable membrane 460 .

[0029] The positive electrode 421 and the negative electrode 422 are plate-shaped electrodes of the lithium desorption device 40. When a voltage is applied to the positive electrode 421 and the negative electrode 422, a voltage is applied to each layer of the main body 420.

[0030] The adsorption layer 424 is provided between the positive electrode 421 and the negative electrode 422. The adsorption layer 424 is provided in contact with the positive electrode 421. An adsorbent having adsorbed lithium ions is supplied to the adsorption layer 424. A liquid is supplied to the adsorption layer 424. This allows the adsorbent to flow within the adsorption layer 424. The adsorption layer 424 transfers lithium ions from manganese oxide contained in the adsorbent to the binding layer 440. The lithium ions desorbed from the adsorbent in the adsorption layer 424 are attracted to the negative electrode 422 by the force of the electric field formed between the positive electrode 421 and the negative electrode 422, and then permeate the first permeable membrane 450 and transfer to the negative electrode 422 (binding layer 440). In other words, when voltages are applied to the positive electrode 421 and the negative electrode 422 of the lithium desorption device 40, the lithium ions attached to the adsorbent in the adsorption layer 424 transfer to the binding layer 440.

[0031] The substance layer 428 is provided between the adsorption layer 424 and the negative electrode 422. A substance to be electrolyzed is supplied to the substance layer 428. The substance layer 428 electrolyzes the supplied substance by applying voltages to the positive electrode 421 and the negative electrode 422, respectively. Hydrogen ions generated by electrolysis in the substance layer 428 become hydrogen gas at the negative electrode 422, and a gas recovery unit 429 that recovers unnecessary hydrogen gas may be connected to the substance layer 428.

[0032] The binding layer 440 is provided between the adsorption layer 424 and the material layer 428. The binding layer 440 is supplied with an electrolyte. The binding layer 440 is supplied with lithium ions that have permeated through the first permeable membrane 450 and anions that have permeated through the second permeable membrane 460. The binding layer 440 generates a lithium compound in the electrolyte, in which the lithium ions and anions are bound together.

[0033] The first permeable membrane 450 is disposed between the adsorption layer 424 and the binding layer 440. The first permeable membrane 450 is a separator that allows the target component (lithium ions) to pass through. The first permeable membrane 450 is preferably a membrane that selectively allows the target substance to pass through while inhibiting the migration of other substances toward the positive electrode 421. The first permeable membrane 450 is, for example, a cation exchange membrane that allows cations to pass through but not anions. The first permeable membrane 450 of this embodiment includes a lithium separator 452 that separates lithium ions from the adsorbent. Various separators that are disposed between the positive and negative electrodes of a lithium-ion secondary battery can be used as the lithium separator 452. By including the lithium separator 452, the first permeable membrane 450 can inhibit the migration of cations other than lithium ions, or more specifically, cations larger than lithium ions, generated in the adsorption layer 424 from the binding layer 440. Any membrane that can selectively transmit lithium can be used as the first permeable membrane 450, and it may be composed of only the lithium separator 452 or only a cation exchange membrane.

[0034] The second permeable membrane 460 is provided between the material layer 428 and the binding layer 440. The second permeable membrane 460 is a membrane that is permeable to anions but not to cations. The second permeable membrane 460 is an anion exchange membrane. The second permeable membrane 460 permeates generated ions from the negative electrode 422 side to the positive electrode 421 side. In other words, the second permeable membrane 460 allows anions ionized in the material layer 428 to permeate the binding layer 440, but does not allow cations ionized in the material layer 428 to permeate the binding layer 440.

[0035] The material layer 428 includes a separation membrane 430. The separation membrane 430 is disposed between the negative electrode 422 and the second permeable membrane 460 of the material layer 428. The separation membrane 430 separates the material layer 428 into two regions between the negative electrode 422 and the second permeable membrane 460. The separation membrane 430 is a laminated membrane in which an anion exchange membrane is disposed on the positive electrode 421 side and a cation exchange membrane is disposed on the negative electrode 422 side, with the two membranes in contact with each other. The separation membrane 430 is, for example, a bipolar membrane, which allows hydrogen ions to pass to the negative electrode side and hydroxide ions to pass to the positive electrode side, but does not allow water molecules to pass through. Water electrolysis occurs in the separation membrane 430 even without ionic components for electrical conduction. The separation membrane 430 allows hydroxide ions, among the ions of water electrolyzed by the separation membrane 430, to move to the positive electrode 421 side and hydrogen ions to move to the negative electrode 422 side. The separation membrane 430 separates the electrolyzed ions of the material layer 428 so that they are unevenly distributed in each region.

[0036] (Electrolysis and Production of Lithium Compounds) Next, a description will be given of the electrolysis and production of lithium compounds performed in the lithium desorption device 40. The lithium desorption device 40 according to the present disclosure produces, for example, lithium hydroxide. These production processes will be described below.

[0037] (Production of lithium hydroxide) In the lithium desorption device 40, a material containing lithium to be separated is supplied to the adsorption layer 424. In this embodiment, the adsorption layer 424 is filled with an adsorbent that has adsorbed lithium contained in seawater. In addition, the lithium desorption device 40 supplies water to the material layer 428 as a material to be electrolyzed.

[0038] The lithium desorption device 40 applies a predetermined voltage to the positive electrode 421 and the negative electrode 422 of the main body 420. By applying a predetermined voltage to the positive electrode 421 and the negative electrode 422, the lithium desorption device 40 causes lithium to be desorbed from the adsorbent in the adsorption layer 424 and electrolysis to occur in the material layer 428. In the adsorption layer 424, lithium becomes lithium ions, which permeate the first permeable membrane 450 and move to the binding layer 440.

[0039] The material layer 428 converts water into hydroxide ions (OH － ) and hydrogen ions (H ＋ ) generated by the electrolysis of the material layer 428. － ) moves to the binding layer 440 through the second permeable membrane 460. In addition, hydrogen ions (H ＋ ) becomes hydrogen gas at the negative electrode 422 and is recovered in the gas recovery vessel 429 .

[0040] The binding layer 440 of the lithium desorption device 40 is supplied with lithium ions that have permeated the first permeable membrane 450 and hydroxide ions that have permeated the second permeable membrane 460. In the binding layer 440, the lithium ions and hydroxide ions are bound to each other to generate lithium hydroxide.

[0041] (Adsorbent Recovery Device) The adsorbent recovery device 42 is connected to the lithium desorption device 40. The adsorbent recovery device 42 recovers the adsorbent contained in the waste liquid, which is the adsorption liquid after the target components of seawater have been desorbed by the lithium desorption device 40. The adsorbent recovery device 42 has, for example, a tank, in which a filter for filtering the adsorbent and a mechanism for supplying the filtered adsorbent to the adsorbent storage tank 20 are provided. The adsorbent recovery device 42 supplies the filtered adsorbent to the adsorbent storage tank 20. This allows the adsorbent to be reused. The adsorbent recovery device 42 also supplies the filtered waste liquid to the waste liquid treatment device 43. Note that the adsorbent recovery device 42 does not necessarily have to be provided.

[0042] (Waste liquid treatment device) One side of the waste liquid treatment device 43 is connected to the adsorbent recovery device 42, and the other side is connected to the sea S. The waste liquid treatment device 43 treats the waste liquid after the adsorbent has been recovered by the adsorbent recovery device 42 so that it can be returned to the sea S, and discharges the treated waste liquid into the sea S. Note that, when the adsorption device 30 treats the waste liquid, one side of the waste liquid treatment device 43 is connected to the adsorption device 30, and the other side is connected to the sea S. In this case, the waste liquid flows from the adsorption device 30 to the waste liquid treatment device 43, and the waste liquid treatment device 43 treats the waste liquid and discharges the treated waste liquid into the sea S.

[0043] (Control Unit) The control unit 90 is a computing device including a CPU (Central Processing Unit), a storage device, etc. The control unit 90 is connected to the adsorbent storage tank 20, the adsorption device 30, the adsorbent recovery device 42, the waste liquid treatment device 43, the lithium desorption device 40, the target component recovery device 50, and the pump P. The control unit 90 controls the functions of the connected devices.

[0044] As described above, the lithium desorption device 40 according to this embodiment includes a positive electrode 421 and a negative electrode 422. The lithium desorption device 40 also includes an adsorption layer 424 that is provided between the positive electrode 421 and the negative electrode 422 and that is supplied with an adsorbent that has adsorbed lithium ions, a substance layer 428 that is provided between the adsorption layer 424 and the negative electrode 422 and that is supplied with a substance to be electrolyzed, and a binding layer 440 that is provided between the adsorption layer 424 and the binding layer 440. The lithium desorption device 40 also includes a first permeable membrane 450 that is provided between the adsorption layer 424 and the binding layer 440 and that allows permeation of lithium ions separated from the adsorbent in the adsorption layer 424, and a second permeable membrane 460 that is provided between the substance layer 428 and the binding layer 440 and that allows permeation of anions ionized from the substance layer 428 in the substance layer 428. In the lithium desorption device 40, lithium ions that have permeated the first permeable membrane 450 and anions that have permeated the second permeable membrane 460 are supplied to the binding layer 440, and a lithium compound in which the lithium ions and anions are bound together is generated. This allows lithium to be appropriately desorbed.

[0045] In addition, the lithium desorption device 40 can vary the lithium compounds that can be generated in the binding layer 440 by varying the material supplied to the material layer 428 .

[0046] (Production of lithium carbonate) Fig. 4 is a schematic diagram showing the structure of another example of a lithium desorption device. In the above embodiment, the case of producing lithium hydroxide has been described, but the present disclosure is not limited to this. The lithium desorption device shown in Fig. 4 produces lithium carbonate. The lithium desorption device shown in Fig. 4 produces lithium carbonate in the material layer 428 as a material to be electrolyzed. ２ CO ３ ) is supplied to the material layer 428. When a current flows through the main body 420, the material layer 428 generates carbonate ions (CO ) by electrolysis of the electrolyte. ３ － The material layer 428 generates carbonate ions (CO ３ － ), and supplies hydrogen gas to the gas recovery unit 429 (negative electrode 422 side). The substance layer 428 supplies carbonate ions generated by electrolysis to the binding layer 440 via the second permeable membrane 460.

[0047] The binding layer 440 is supplied with the lithium ions that have permeated through the first permeable membrane 450 and the carbonate ions that have permeated through the second permeable membrane 460. The binding layer 440 generates lithium carbonate in which the lithium ions and carbonate ions are bound together.

[0048] The product produced in the binding layer 440 of the lithium desorption device 40 is supplied to the target component collector 50 and collected therein.

[0049] [Second Embodiment] Fig. 5 is a schematic diagram showing the overall configuration of a target component recovery system according to a second embodiment. In this embodiment, the recovery efficiency of lithium, which is a target component, is improved by heating the adsorption solution and the like using exhaust heat from the plant 100. In the second embodiment, components similar to those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

[0050] The target component recovery system 1A includes a plant 100, a water intake facility 10, an adsorbent storage tank 20, an adsorbent separation device 28, an adsorption device 30, an adsorbent recovery device 42, a waste liquid treatment device 43, a lithium desorption device 40, a target component recovery device 50, a heat exchanger 80, and a control unit 90A. The target component recovery system 1A is a system that recovers a target component (resource) contained in a solution by performing a predetermined treatment.

[0051] (Heat Exchanger) The temperature of seawater taken from the water intake facility 10 is not always constant due to seasonal and other factors. As a result, the temperature of the seawater may become low, and even if an adsorbent is added, the recovery efficiency of the target components may decrease. In contrast, in this embodiment, the heat exchanger 80 is used to heat the seawater, thereby suppressing a decrease in the recovery efficiency of the target components and enabling the target components to be appropriately recovered. The heat exchanger 80 will be described below.

[0052] The heat exchanger 80 heats the seawater taken in by the water intake facility 10 by exchanging heat between the exhaust heat medium from the plant 100 and the seawater taken in by the water intake facility 10. The heat exchanger 80 is connected to a pipe through which the exhaust heat medium from the plant 100 flows, and the exhaust heat medium is supplied from the pipe. The heat exchanger 80 is also disposed in a position where it can heat the seawater taken in by the water intake facility 10. This allows the heat exchanger 80 to heat the seawater taken in by the water intake facility 10 using the exhaust heat medium from the plant 100. Here, the seawater taken in by the water intake facility 10 refers to the seawater (or the adsorption solution) after it has been taken in by the water intake facility 10 and before it is supplied to the lithium desorption device 40. That is, the heat exchanger 80 heats the seawater (or the adsorption solution) between the position where the water intake facility 10 is provided and the position where the lithium desorption device 40 is provided, in the direction in which the seawater (or the adsorption solution) flows within the target component recovery system 1A. It is more preferable that the heat exchanger 80 heats the seawater (or the adsorption solution) after it has been discharged from the condenser 101 and before it is supplied to the lithium desorption device 40. By heating the seawater (or the adsorption solution) using the heat exchanger 80 in this way, the seawater can be appropriately heated using the exhaust heat from the plant 100, and the target components can be appropriately recovered.

[0053] In the present embodiment, the heat exchanger 80 preferably heats the seawater (adsorption liquid) in the adsorption device 30. That is, the heat exchanger 80 is disposed at a position where it can heat the seawater in the adsorption device 30. For example, the heat exchanger 80 is disposed within a predetermined distance from the adsorption device 30 (within a distance range where the seawater in the adsorption device 30 can be heated). For example, the heat exchanger 80 may be disposed at a position where it contacts the outer wall of the adsorption device 30, or may be disposed within the adsorption device 30.

[0054] The heat exchanger 80 preferably heats the seawater taken into the water intake facility 10 (in this example, the seawater in the adsorption device 30) to maintain the temperature of the seawater within an appropriate temperature range. The appropriate temperature range of the seawater may be set as appropriate. For example, the heat exchanger 80 controls the degree of heating according to the flow rate of seawater taken in by the pump P to heat the seawater so as to maintain the appropriate temperature range. For example, the heat exchanger 80 may be provided with a valve capable of controlling the amount of exhaust heat medium supplied to the heat exchanger 80, and the control unit 90A may control the opening and closing of the valve according to the flow rate of seawater taken in by the pump P to control the amount of exhaust heat medium supplied and thereby the degree of heating. Furthermore, for example, if the exhaust heat medium is discharged from multiple locations in the plant 100, the heat exchanger 80 may be connectable to pipes from each location in the plant 100. In this case, for example, the control unit 90A selects a pipe to connect to the heat exchanger 80 from the pipes leading from each location in the plant 100 in accordance with the flow rate of seawater taken in by the pump P, and connects the selected pipe to the heat exchanger 80. This makes it possible to supply an exhaust heat medium having a heat quantity according to the flow rate of seawater, thereby allowing the seawater to be appropriately heated.

[0055] The heat exchanger 80 is not limited to heating the seawater in the adsorption device 30, and may, for example, heat the seawater flowing through the pipe (discharge channel) 16 connected between the water intake facility 10 and the adsorption device 30. In this case, the heat exchanger 80 is disposed at a position where it can heat the seawater in the discharge channel 16. For example, the heat exchanger 80 is disposed within a predetermined distance from the discharge channel 16 (within a distance range where the seawater in the discharge channel 16 can be heated). For example, the heat exchanger 80 may be disposed at a position where it contacts the outer peripheral surface of the discharge channel 16.

[0056] Furthermore, a plurality of heat exchangers may be provided. In this case, for example, a heat exchanger 80 for heating the seawater (adsorption liquid) in the adsorption device 30 and a heat exchanger 80 for heating the seawater in the discharge channel 16 may be provided.

[0057] (Control Unit) The control unit 90A is a computing device including a CPU (Central Processing Unit), a storage device, etc. The control unit 90A is connected to the adsorbent storage tank 20, the mixing tank 26, the adsorbent separation device 28, the adsorption device 30, the adsorbent recovery device 42, the waste liquid treatment device 43, the lithium desorption device 40, the heat exchanger 80, and the pump P. The control unit 90A controls the functions of the connected devices. For example, the control unit 90A controls the heat exchange (amount of exhaust heat) by the heat exchanger 80.

[0058] The adsorbent recovery device 42 may also be connected to the adsorption device 30. In this manner, the target component recovery system 1A can appropriately recover target components contained in seawater by performing heat exchange using the heat exchanger 80.

[0059] <Effects> The lithium desorption device according to the first aspect of the present disclosure includes a positive electrode 421, a negative electrode 422, an adsorption layer 424 provided between the positive electrode 421 and the negative electrode 422 and supplied with an adsorbent having adsorbed lithium ions, a substance layer 428 provided between the adsorption layer 424 and the negative electrode 422 and supplied with a substance to be electrolyzed, a binding layer 440 provided between the adsorption layer 424 and the substance layer 428, a first permeable membrane 450 provided between the adsorption layer 424 and the binding layer 440 and allowing permeation of lithium ions separated from the adsorbent in the adsorption layer 424, and a second permeable membrane 460 provided between the substance layer 428 and the binding layer 440 and allowing permeation of anions ionized from the substance layer 428 in the substance layer 428, and the binding layer 440 is supplied with the lithium ions that have permeated the first permeable membrane 450 and the anions that have permeated the second permeable membrane 460, and a lithium compound in which the lithium ions and the anions are bound to each other is produced. In this way, lithium can be desorbed from the adsorbent without using an acid, and therefore a decrease in the absorption rate of the adsorbent can be suppressed, thereby enabling lithium to be desorbed appropriately.

[0060] The lithium desorption device according to the second aspect of the present disclosure is the lithium desorption device according to the first aspect, in which water is supplied to the substance layer 428 and hydroxide ions that have permeated the second permeable membrane 460 are supplied to the binding layer 440, thereby generating lithium hydroxide. This allows lithium to be recovered from the lithium hydroxide.

[0061] The lithium desorption device according to the third aspect of the present disclosure is the lithium desorption device according to the first or second aspect, in which carbonic acid is supplied to the material layer 428 and carbonate ions that have permeated the second permeable membrane 460 are supplied to the binding layer 440, thereby generating lithium carbonate. This allows lithium to be recovered from the lithium carbonate.

[0062] A lithium desorption device according to a fourth aspect of the present disclosure is the lithium desorption device according to any one of the first to third aspects, wherein the adsorbent is a spinel-type manganese oxide and iron phosphate, thereby enabling appropriate desorption of lithium.

[0063] REFERENCE SIGNS LIST 1, 1A Target component recovery system 10 Water intake facility 12 Water intake channel 14 Screen 16 Discharge channel 20 Adsorbent storage tank 30 Adsorption device 40 Lithium desorption device 42 Adsorbent recovery device 43 Waste liquid treatment device 50 Target component recovery device 80 Heat exchanger 90, 90A Control unit 100 Plant 101 Condenser 101a Steam flow path 101b Condenser channel 410 Power supply unit 411 Wiring 412 Power supply 420 Main body 421 Positive electrode 422 Negative electrode 424 Adsorption layer 428 Material layer 429 Gas recovery device 430 Separation membrane 440 Binder layer 450 First permeable membrane 452 Lithium separator 460 Second permeable membrane

Claims

1. A lithium desorption device comprising a positive electrode, a negative electrode, an adsorption layer provided between the positive electrode and the negative electrode and supplied with an adsorbent adsorbed with lithium ions, a substance layer provided between the adsorption layer and the negative electrode and supplied with a substance to be electrolyzed, a bonding layer provided between the adsorption layer and the substance layer, a first permeable membrane provided between the adsorption layer and the bonding layer and permeable to lithium ions separated from the adsorbent in the adsorption layer to the bonding layer, and a second permeable membrane provided between the substance layer and the bonding layer and permeable to anions ionized from the substance layer in the substance layer and impermeable to cations, wherein the bonding layer is supplied with the lithium ions that have passed through the first permeable membrane and the anions that have passed through the second permeable membrane, and a lithium compound in which the lithium ions and the anions are combined is generated.

2. The lithium desorption device according to claim 1, wherein water is supplied to the substance layer, the bonding layer is supplied with hydroxide ions that have passed through the second permeable membrane from the substance layer, and lithium hydroxide is generated.

3. The lithium desorption device according to claim 1 or 2, wherein carbonic acid is supplied to the substance layer, the bonding layer is supplied with carbonate ions that have passed through the second permeable membrane from the substance layer, and lithium carbonate is generated.

4. The lithium desorption device according to claim 1 or 2, wherein the adsorbent is spinel-type manganese oxide and iron phosphate.

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