Lithium desorption device

Abstract

To properly desorb lithium while suppressing deterioration of an adsorbent.SOLUTION: A lithium desorption device includes: a positive electrode; a negative electrode; an adsorption layer provided between the positive electrode and the negative electrode, to which an adsorbent having adsorbed lithium ions is supplied; a material layer provided between the adsorption layer and the negative electrode, to which a substance to be electrolyzed is supplied; a bonding layer provided between the adsorption layer and the material layer; a first transmission membrane provided between the adsorption layer and the bonding layer, which transmits lithium ions separated from the adsorbent in the adsorption layer; and a second transmission membrane provided between the material layer and the bonding layer, which transmits anions ionized from the material layer. In the bonding layer, lithium ions transmitted through the first transmission membrane and anions transmitted through the second transmission membrane are supplied, and a lithium compound in which the lithium ions and the anions are combined is produced.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] Technologies for recovering resources contained in seawater from seawater have been disclosed. For example, Patent Document 1 discloses that lithium in seawater is adsorbed by an adsorbent, and the lithium is desorbed as ions from the adsorbent by passing the adsorbent through a weak acid solution. A technology for recovering lithium by blowing and bubbling carbon dioxide gas discharged from a power plant and recovering it as lithium carbonate has been disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is known that the adsorbent deteriorates due to weak acid treatment, and there is room for improvement to increase the reuse rate of the adsorbent in order to appropriately recover the target components contained in seawater.

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

Means for Solving the Problems

[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 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, 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. In the bonding layer, the lithium ions that have passed through the first permeable membrane and the anions that have passed through the second permeable membrane are supplied, and a lithium compound in which the lithium ions and the anions are combined is generated.

Advantages of the Invention

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

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0009] Hereinafter, with reference to the drawings, preferred embodiments of the present disclosure will be described in detail. Note that the present disclosure is not limited by this embodiment, and when there are multiple embodiments, those configured by combining each embodiment are also included. In addition, the components in the embodiment include those that can be easily assumed by those skilled in the art, substantially the same ones, and those within the so-called equivalent range. Furthermore, the components in the embodiments described below can be subject to various omissions, substitutions, or changes in configuration without departing from the gist of the present invention.

[0010] [First Embodiment] The target component recovery system 1 according to this embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic diagram showing the overall configuration of the target component recovery system according to the first embodiment. FIG. 2 is a schematic diagram showing the flow of the target component 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 separation device 28, an adsorption device 30, a waste liquid processor 43, a lithium desorption device 40, a target component recovery device 50, and a control unit 90. The target component recovery system 1 is a system that performs predetermined processing on the target component (resource) contained in the solution to recover the target component. Here, the solution is preferably any one of seawater, concentrated drainage of a seawater desalination facility that generates fresh water from seawater, and salt lake brine. In addition, examples of the target component include lithium, uranium, and magnesium, but are not limited to these target components as long as they are target components that can be recovered using the system of the present disclosure. Hereinafter, the solution will be described as seawater and the target component as lithium. That is, the target component recovery system according to the present disclosure is a system that recovers lithium contained in seawater.

[0012] (Plant) Plant 100 is a facility that produces resources, materials, etc. necessary for industrial activities. It is preferable that Plant 100 uses seawater taken from the water intake facility 10 described below. Also, Plant 100 discharges an exhaust heat medium, which is a heated medium generated during operation. The exhaust heat medium may be any medium. For example, when a steam turbine is provided in Plant 100, the steam after driving the steam turbine may be used as the exhaust heat medium. Also, for example, when a boiler is provided in Plant 100, the steam after being used in the boiler may be used as the exhaust heat medium. Further, Plant 100 may discharge the exhaust heat medium from a plurality of locations. Plant 100 may be any facility that uses seawater and discharges an exhaust heat medium, and examples include nuclear power generation facilities, thermal power generation facilities, chemical plants, etc. In this embodiment, Plant 100 will be described by taking a nuclear power generation facility as an example. Also, in this embodiment, it is preferable that Plant 100 is an operating plant.

[0013] (Nuclear power generation facility) Here, an overview of the nuclear power generation facility (nuclear facility) will be described. The nuclear facility has, for example, a pressurized water reactor (PWR). The nuclear facility uses the heat generated in the pressurized water reactor to generate electricity, for example. The nuclear facility uses light water as the reactor coolant and neutron moderator to make high-temperature and high-pressure water that does not boil throughout the reactor core. This high-temperature and high-pressure water (primary coolant) is sent to a steam generator to generate steam by heat exchange. Then, this steam (secondary coolant) is sent to a turbine generator to generate electricity. Here, the secondary coolant becomes steam by the heat of the high-temperature and high-pressure primary coolant from the reactor in the steam generator, is cooled by seawater in the condenser 101 after driving the steam turbine to become condensate, and is returned to the steam generator again by a condensate pump. Note that the nuclear facility may be a nuclear facility using a boiling water reactor (BWR).

[0014] The condenser 101 cools the secondary coolant with seawater from the sea S after the secondary coolant drives the steam turbine to generate electricity and produces condensate. The steam, which is the secondary coolant, passes through the steam flow path 101a and is sent to the condenser 101. The condenser 101 supplies the generated condensate to the steam generator through the condensate 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 the sea S, which is the intake target adjacent to the plant 100 (nuclear facility) in this embodiment, supplies the obtained seawater to the condenser 101, and discharges the seawater discharged from the condenser 101 to the adsorption device 30. The water intake facility 10 includes a water intake path 12, a screen 14, a discharge path 16, and a pump P.

[0016] The water intake path 12 is a water path with one end connected to the sea S and the other end connected to the condenser 101. Seawater from the sea S flows into the water intake path 12 and is supplied to the condenser 101. A certain range from the side connected to the condenser 101 forms a pipeline. The part of the water intake path 12 connected to the sea S may be, for example, a water path with an open upper surface.

[0017] The screen 14 is provided in the middle of the water intake path 12. The screen 14 is a mesh-like member. The screen 14 removes foreign substances contained in the seawater. The seawater passes through the screen 14 and flows into the condenser 101 by the pump P provided ahead.

[0018] One end of the discharge path 16 is connected to the condenser 101, and the other end is connected to the adsorption device 30. A part of the discharge path 16 on the side connected to the condenser 101 is, for example, in a hollow cylindrical shape, and the seawater that has cooled the secondary coolant in the condenser 101 flows toward the adsorption device 30. That is, it can be said that the discharge path 16 is a pipe connecting the water intake facility 10 and the adsorption device 30.

[0019] The pump P flows the seawater taken in from the water intake passage 12 to 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 the target component in the 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 provided in 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 the present embodiment, the adsorbent storage tank 20 stores the adsorbent in a state where the adsorbent and the liquid are mixed. 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 arbitrary, but may be, for example, water.

[0021] Here, the adsorbent will be described. The adsorbent is a substance that adsorbs the target component (resource) contained in a solution (e.g., seawater). The adsorbent adsorbs, for example, the target component contained in the form of ions in seawater. The adsorbent may be, for example, in powder form. The adsorbent may be any substance capable of adsorbing the target component. For example, when the target component to be recovered is lithium, manganese oxide may be used as the adsorbent. For example, in this case, it is preferable that the adsorbent is manganese oxide in which openings of a size allowing lithium ions to penetrate are formed so that lithium ions can be collected. For example, the adsorbent is preferably spinel-type manganese oxide (λ-MnO2) or iron phosphate (FePO4). Also, for example, when the target component is uranium, an adsorbent (moll) different from manganese oxide may be used. Also, multiple types of adsorbents may be used for the adsorbent. However, the adsorbent is not limited to dedicated manganese oxide for recovering lithium or moll 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 dedicated manganese oxide for recovering lithium. Thereby, it becomes 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] Seawater as a solution taken in by the water intake facility 10 is supplied to the adsorption device 30 via the drain channel 16. That is, the seawater taken in by the water intake facility 10 flows into the adsorption device 30 through the drain channel 16 after heat exchange in the condenser 101. Also, an adsorbent is supplied to the adsorption device 30 from the adsorbent storage tank 20. Thereby, in the adsorption device 30, the adsorbent is added to the seawater, and an adsorption liquid containing the seawater and the adsorbent is generated. Note that, for example, a stirrer for stirring the seawater and the adsorbent may be provided in the adsorption device 30.

[0024] In the adsorption device 30, it is preferable to store the seawater with the adsorbent added (adsorption liquid) for a predetermined period (for example, about several days to 14 days) in a state where the adsorbent is added to the seawater. By storing for such a predetermined period, the target component can be appropriately adsorbed by the adsorbent. When storing the seawater for such a predetermined period, while the seawater in one adsorption device 30 is being stored, seawater can be taken into another adsorption device 30 and the adsorbent can be added. That is, the target component recovery system 1 can efficiently perform the recovery process by taking in seawater into another adsorption device 30 while taking in seawater into the adsorption device 30. Therefore, it is preferable that a plurality of adsorption devices 30 are provided in the target component recovery system 1. More specifically, after taking in seawater into the adsorption device 30 and adding the adsorbent, while stopping the supply of seawater to that adsorption device 30, seawater can be taken into another adsorption device 30. By performing this on a plurality of adsorption devices 30, the target component can be efficiently recovered.

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

[0026] FIG. 3 is a schematic diagram showing the structure of the lithium desorption device. When an electric current flows, the lithium desorption device 40 desorbs lithium ions (Li + ) from the adsorbent by electrolysis. The lithium desorption device 40 generates a lithium compound from the desorbed lithium ions. Electrolysis and the 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 the positive electrode 421 and the negative electrode 422 of the main body 420. The power supply 412 is provided in the middle of 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 an electric current flows, the power supply unit 410 divides the voltage applied to the power supply 412 to the main body 420.

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

[0029] The positive electrode 421 and the negative electrode 422 are electrodes of the lithium desorption device 40 and are plate-shaped. 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 adsorbed with lithium ions is supplied to the adsorption layer 424. A liquid is supplied to the adsorption layer 424. Thereby, the adsorbent can flow in the adsorption layer 424. The adsorption layer 424 moves lithium ions from manganese oxide contained in the adsorbent to the bonding layer 440. The lithium ions desorbed from the adsorbent in the adsorption layer 424 are attracted to the negative electrode 422 side by the force of the electric field formed between the positive electrode 421 and the negative electrode 422, and permeate through the first permeable membrane 450 and move to the negative electrode 422 side (bonding layer 440). That is, 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 move to the bonding layer 440 in the adsorption layer 424.

[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 when voltages are applied to the positive electrode 421 and the negative electrode 422 respectively. The hydrogen ions generated by the electrolysis in the substance layer 428 become hydrogen gas at the negative electrode 422, and a gas recovery device 429 for recovering unnecessary hydrogen gas may be connected.

[0032] The bonding layer 440 is provided between the adsorption layer 424 and the substance layer 428. An electrolytic solution is supplied to the bonding layer 440. Lithium ions that have permeated through the first permeable membrane 450 and anions that have permeated through the second permeable membrane 460 are supplied to the bonding layer 440. The bonding layer 440 generates a lithium compound in which lithium ions and anions are combined in the electrolytic solution.

[0033] The first permeable membrane 450 is provided between the adsorption layer 424 and the bonding layer 440. The first permeable membrane 450 is a separator that allows the target component (lithium ions) to permeate. The first permeable membrane 450 is preferably a membrane that selectively permeates the target substance and suppresses the movement of other substances to the positive electrode 421 side. The first permeable membrane 450 is, for example, a cation exchange membrane that allows cations to permeate and does not allow anions to permeate. The first permeable membrane 450 of the present embodiment includes a lithium separator 452 that separates lithium ions from the adsorbent. As the lithium separator 452, various separators disposed between the positive electrode and the negative electrode of a lithium ion secondary battery can be used. By including the lithium separator 452, the first permeable membrane 450 can suppress the generated cations other than lithium ions generated in the adsorption layer 424, more precisely, cations larger than lithium ions, from moving to the bonding layer 440. Any membrane can be used as long as the first permeable membrane 450 can selectively permeate lithium, and it may be only the lithium separator 452 or only the cation exchange membrane.

[0034] The second permeable membrane 460 is provided between the substance layer 428 and the bonding layer 440. The second permeable membrane 460 is a membrane that allows anions to permeate and does not allow cations to permeate. The second permeable membrane 460 is an anion exchange membrane. The second permeable membrane 460 allows the generated ions to permeate from the negative electrode 422 side to the positive electrode 421 side. That is, the second permeable membrane 460 allows the anions ionized in the substance layer 428 to permeate into the bonding layer 440 and does not allow the cations ionized in the substance layer 428 to permeate into the bonding layer 440.

[0035] The material layer 428 has a separation membrane 430. The separation membrane 430 is disposed between the negative electrode 422 of the material layer 428 and the second permeation membrane 460. The separation membrane 430 separates the material layer 428 into two regions between the negative electrode 422 and the second permeation 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, and the two membranes are in contact with each other. The separation membrane 430 is, for example, a bipolar membrane that permeates hydrogen ions to the negative electrode side, permeates hydroxide ions to the positive electrode side, and does not permeate water molecules. Even when there is no ionic component for electric conduction in the separation membrane 430, electrolysis of water occurs. The separation membrane 430 enables hydroxide ions among the ions of the water electrolyzed by the separation membrane 430 to move to the positive electrode 421 side and enables hydrogen ions to move to the negative electrode 422 side. The separation membrane 430 separates the electrolyzed ions of the material layer 428 so as to be unevenly distributed in the respective regions.

[0036] (Electrolysis and Lithium Compound Generation) Next, the electrolysis and lithium compound generation performed by the lithium desorption device 40 will be described. The lithium desorption device 40 according to the present disclosure generates, for example, lithium hydroxide. Hereinafter, these generation processes will be described.

[0037] (Lithium Hydroxide Generation) The lithium desorption device 40 is supplied with a substance containing lithium to be separated to the adsorption layer 424. In the present embodiment, an adsorbent that adsorbs lithium contained in seawater is filled. Further, the lithium desorption device 40 supplies water as a substance to be electrolyzed to the material layer 428.

[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 desorption from the adsorbent in the adsorption layer 424 and electrolysis in the material layer 428. In the adsorption layer 424, lithium becomes lithium ions, permeates through the first permeation membrane 450, and moves to the bonding layer 440.

[0039] The material layer 428 converts water into hydroxide ions (OH- ) and hydrogen ions (H + ) are electrolyzed. The hydroxide ions (OH - ) generated by the electrolysis of the material layer 428 move to the bonding layer 440 through the second permeable membrane 460. Also, the hydrogen ions (H + ) in the material layer 428 become hydrogen gas at the negative electrode 422 and are recovered by the gas recovery device 429.

[0040] The bonding layer 440 of the lithium desorption device 40 is supplied with lithium ions that have passed through the first permeable membrane 450 and hydroxide ions that have passed through the second permeable membrane 460. In the bonding layer 440, lithium ions and hydroxide ions combine to produce 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 liquid after the target component of seawater has been desorbed in the lithium desorption device 40. The adsorbent recovery device 42 has, for example, a tank, and is provided with a filter for filtering the adsorbent therein and a mechanism for supplying the filtered adsorbent to the adsorbent storage tank 20. The adsorbent recovery device 42 supplies the filtered adsorbent to the adsorbent storage tank 20. Thereby, the adsorbent can be reused. Also, the adsorbent recovery device 42 supplies the filtered waste liquid to the waste liquid processor 43. Note that the adsorbent recovery device 42 may not be provided.

[0042] (Waste Liquid Processor) One side of the waste liquid processor 43 is connected to the adsorbent recovery device 42, and the other side is connected to the sea S. The waste liquid processor 43 processes the waste liquid after the adsorbent has been recovered by the adsorbent recovery device 42 into a state where it can be returned to the sea S, and flows the processed waste liquid into the sea S. Note that when the adsorbent device 30 processes the waste liquid, one side of the waste liquid processor 43 is connected to the adsorbent device 30, and the other side is connected to the sea S. In this case, the waste liquid flows from the adsorbent device 30 to the waste liquid processor 43, and the waste liquid processor 43 processes the waste liquid and flows the processed waste liquid into the sea S.

[0043] (Control Unit) The control unit 90 is an arithmetic unit equipped with 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 processor 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 the present embodiment is provided with a positive electrode 421 and a negative electrode 422. Further, the lithium desorption device 40 is provided between the positive electrode 421 and the negative electrode 422, and an adsorption layer 424 to which an adsorbent that has adsorbed lithium ions is supplied, and between the adsorption layer 424 and the negative electrode 422, and a substance layer 428 to which a substance to be electrolyzed is supplied, and a binding layer 440 provided between the adsorption layer 424 and the substance layer 428. Furthermore, the lithium desorption device 40 is provided between the adsorption layer 424 and the binding layer 440, and a first permeation membrane 450 that permeates lithium ions separated from the adsorbent in the adsorption layer 424, and between the substance layer 428 and the binding layer 440, and a second permeation membrane 460 that permeates anions ionized from the substance layer 428 in the substance layer 428. In the binding layer 440 of the lithium desorption device 40, lithium ions that have permeated through the first permeation membrane 450 and anions that have permeated through the second permeation membrane 460 are supplied, and a lithium compound in which the lithium ions and the anions are combined is generated. Thereby, lithium can be appropriately desorbed.

[0045] Also, the lithium desorption device 40 can vary the lithium compound that can be generated in the binding layer 440 by varying the substance supplied to the substance layer 428.

[0046] (Production of Lithium Carbonate) FIG. 4 is a schematic diagram showing the structure of another example of the lithium desorption device. In the above embodiment, the case of generating lithium hydroxide has been described, but the present disclosure is not limited thereto. The lithium desorption device shown in FIG. 4 generates lithium carbonate. In the lithium desorption device shown in FIG. 4, carbonic acid (H2CO3) is supplied to the substance layer 428 as the substance to be electrolyzed. The substance layer 428 is supplied with an electrolytic solution. When an electric current flows through the main body 420 in the substance layer 428, carbonate ions (CO3 - ) are generated by electrolysis of the electrolytic solution. The substance layer 428 generates carbonate ions (CO3 - ) that react with lithium ions, and supplies hydrogen gas to the gas recovery device 429 (on the negative electrode 422 side). The substance layer 428 supplies the carbonate ions generated by electrolysis to the bonding layer 440 through the second permeable membrane 460.

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

[0048] The product generated in the bonding layer 440 of the lithium desorption device 40 is supplied to the target component recovery device 50 and recovered by the target component recovery device 50.

[0049] 〔Second Embodiment〕 FIG. 5 is a schematic diagram showing the overall configuration of the target component recovery system according to the second embodiment. In the present embodiment, the waste heat of the plant 100 is used to heat the adsorption liquid or the like, thereby improving the recovery efficiency of lithium, which is the target component. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is 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 processor 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 performs predetermined processing on a target component (resource) contained in a solution and recovers the target component.

[0051] (Heat exchanger) The seawater taken in from the water intake facility 10 does not always have a constant temperature due to the influence of seasons and the like. Therefore, there are cases where the temperature of the seawater becomes low, and even if an adsorbent is added, the recovery efficiency of the target component may decrease. On the other hand, in the present embodiment, by using the heat exchanger 80 to heat the seawater, it is possible to suppress a decrease in the recovery efficiency of the target component and appropriately recover the target component. Hereinafter, the heat exchanger 80 will be described.

[0052] The heat exchanger 80 heats the seawater taken into the water intake facility 10 by exchanging heat between the waste heat medium from the plant 100 and the seawater taken into the water intake facility 10. The heat exchanger 80 is connected to the pipe through which the waste heat medium from the plant 100 flows, and the waste heat medium is supplied from that pipe. Further, the heat exchanger 80 is disposed at a position where the seawater taken into the water intake facility 10 can be heated. Thereby, the heat exchanger 80 can heat the seawater taken into the water intake facility 10 with the waste heat medium from the plant 100. The seawater taken into the water intake facility 10 here refers to the seawater (or the adsorption liquid) after being taken into the water intake facility 10 and before being supplied to the lithium desorption device 40. That is, the heat exchanger 80 heats the seawater (or the adsorption liquid) between the position where the water intake facility 10 is provided and the position where the lithium desorption device 40 is provided in the flowing direction of the seawater (or the adsorption liquid) within the target component recovery system 1A. It is more preferable that the heat exchanger 80 heats the seawater (or the adsorption liquid) after being discharged from the condenser 101 and before being supplied to the lithium desorption device 40. Thus, by heating the seawater (or the adsorption liquid) with the heat exchanger 80, the waste heat from the plant 100 can be used to appropriately heat the seawater, and the target component can be appropriately recovered.

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

[0054] The heat exchanger 80 preferably maintains the temperature of the seawater (seawater in the adsorption device 30 in this example) taken into the water intake facility 10 within an appropriate temperature range by heating it. The appropriate temperature range of the seawater here may be set as appropriate. For example, the heat exchanger 80 controls the degree of heating according to the flow rate of the seawater taken in by the pump P and heats it so as to maintain the appropriate temperature range of the seawater. For example, the heat exchanger 80 is provided with a valve capable of controlling the supply amount of the waste heat medium to the heat exchanger 80, and the control unit 90A controls the opening and closing of the valve according to the flow rate of the seawater taken in by the pump P, thereby controlling the supply amount of the waste heat medium and controlling the degree of heating. Also, for example, when the waste heat medium is discharged from a plurality of locations in the plant 100, the heat exchanger 80 may be connectable to pipes from each location of the plant 100. In this case, for example, the control unit 90A selects the pipe to be connected to the heat exchanger 80 from among the pipes from each location of the plant 100 according to the flow rate of the seawater taken in by the pump P and connects the selected pipe to the heat exchanger 80. Thereby, it becomes possible to supply a waste heat medium having a heat quantity corresponding to the flow rate of the seawater, and the seawater can be heated appropriately.

[0055] Note that the heat exchanger 80 is not limited to heating the seawater in the adsorption device 30, and for example, it may 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 arranged at a position where it can heat the seawater in the discharge channel 16. For example, the heat exchanger 80 is arranged within a predetermined distance range 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 arranged at a position in contact with the outer peripheral surface of the discharge channel 16.

[0056] Also, 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 an arithmetic unit including a CPU (Central Processing Unit) and a storage device. The control unit 90A is connected to an adsorbent storage tank 20, a mixing tank 26, an adsorbent separation device 28, an adsorption device 30, an adsorbent recovery device 42, a waste liquid processor 43, a lithium desorption device 40, a heat exchanger 80, and a pump P. The control unit 90A controls the functions of the connected devices. For example, the control unit 90A controls the heat exchange (waste heat amount) by the heat exchanger 80.

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

[0059] <Effect> 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 that has 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 bonding 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 bonding layer 440 and permeable to 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 bonding layer 440 and permeable to anions ionized from the substance layer 428 in the substance layer 428. In the bonding layer 440, lithium ions that have passed through the first permeable membrane 450 and anions that have passed through the second permeable membrane 460 are supplied, and a lithium compound in which the lithium ions and the anions are combined is generated. By doing so, lithium can be desorbed from the adsorbent without using an acid, so that a decrease in the absorption rate of the adsorbent can be suppressed. Therefore, lithium can be appropriately desorbed.

[0060] The lithium desorption device according to the second aspect of the present disclosure is the lithium desorption device according to the first aspect, wherein water is supplied to the material layer 428, and hydroxide ions that have permeated through the second permeable membrane 460 are supplied to the binding layer 440, and lithium hydroxide is generated. Thereby, lithium can be recovered from 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 aspect or the second aspect, wherein carbonic acid is supplied to the material layer 428, and carbonate ions that have permeated through the second permeable membrane 460 are supplied to the binding layer 440, and lithium carbonate is generated. Thereby, lithium can be recovered from lithium carbonate.

[0062] The lithium desorption device according to the fourth aspect of the present disclosure is the lithium desorption device according to any one of the first aspect to the third aspect, and the adsorbent is spinel-type manganese oxide and iron phosphate. Thereby, lithium can be appropriately desorbed.

Explanation of Signs

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

Claims

1. a positive electrode, a negative electrode, an adsorption layer provided between the positive electrode and the negative electrode and supplied with an adsorbent that has adsorbed 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 allowing lithium ions separated from the adsorbent in the adsorption layer to permeate into the bonding layer, a second permeable membrane provided between the substance layer and the bonding layer and allowing anions ionized from the substance layer in the substance layer to permeate therethrough but not allowing cations to permeate therethrough, and having, the bonding layer being supplied with the lithium ions that have permeated through the first permeable membrane and the anions that have permeated through the second permeable membrane, and a lithium compound being formed by the combination of the lithium ions and the anions, a lithium desorption device.

2. water being supplied to the substance layer, the bonding layer being supplied with hydroxide ions that have permeated through the second permeable membrane from the substance layer, and lithium hydroxide being formed, the lithium desorption device according to Claim 1.

3. carbonic acid being supplied to the substance layer, the bonding layer being supplied with carbonate ions that have permeated through the second permeable membrane from the substance layer, and lithium carbonate being formed, the lithium desorption device according to Claim 1 or Claim 2.

4. the adsorbent being spinel-type manganese oxide and iron phosphate, the lithium desorption device according to Claim 1 or Claim 2.

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