JP6652518B2 - Transition metal recovery method and transition metal recovery device - Google Patents

Description

  An embodiment of the present invention relates to a transition metal recovery method and a transition metal recovery device.

  A fuel cell is a clean power generation device that generates power by reacting hydrogen and oxygen and does not generate carbon dioxide during power generation. In particular, polymer electrolyte fuel cells (PEFCs) have advantages over other types of fuel cells, such as low-temperature operation and easy downsizing. Therefore, PEFC is commercially available as a distributed power source for home use. Furthermore, the mounting of PEFC on a fuel cell vehicle is being studied, and there is a high possibility that PEFC will become more widely used than before.

  The PEFC includes a membrane electrode assembly (MEA: Membrane Electrode Assembly) as an electrode material. The MEA contains a transition metal such as Pt (platinum) as a catalyst component. Generally, the transition metal used for the catalyst component of the MEA has a small amount of resources and is expensive.

  Therefore, it has been studied to recover and recycle transition metals such as Pt used in the MEA from the MEA. For example, there is a method of incinerating MEA. In this method, transition metals are recovered by selecting incineration residues generated by incineration of MEA. In recent years, a method of immersing the MEA in an acidic solution containing halide ions and applying a voltage to the MEA immersed in the solution to recover the transition metal has been studied.

JP 2015-161019 A

  The MEA is provided inside the fuel cell. Therefore, in any of the above methods, it is necessary to disassemble the fuel cell and take out the MEA from the fuel cell. Therefore, there is a need for a method for easily recovering transition metals from a fuel cell.

  An object of the present invention is to provide a transition metal recovery method and a transition metal recovery device that can easily recover a transition metal from a fuel cell without disassembling the fuel cell.

The transition metal recovery method of the embodiment supplies a solution to a fuel electrode flow path inlet for supplying fuel gas to the fuel cell or a fuel electrode flow path outlet for discharging fuel gas from the fuel cell, A step of immersing the fuel electrode, and supplying a solution to an air electrode channel inlet for supplying air to the fuel cell or an air electrode channel outlet for discharging air from the fuel cell, and immersing the air electrode in the solution And the fuel electrode and the air immersed in the solution via a fuel electrode output terminal electrically connected to the fuel electrode and an air electrode output terminal electrically connected to the air electrode. A step of applying a voltage to an electrode to dissolve the transition metal contained in the fuel electrode and the air electrode in the solution, and including the transition metal from the fuel electrode channel outlet or the fuel electrode channel inlet Discharging the lysis solution; From electrode channel outlet or the air flow channel entrance, it possesses a step of discharging the solution containing the transition metal, to discharge the cooling water from the cooling water passage inlet or fuel cell for supplying cooling water to the fuel cell The method further includes a step of supplying a solution to a cooling water channel outlet and a step of discharging the solution from the cooling water channel outlet or the cooling water channel inlet .

  According to the embodiment, it is possible to provide a transition metal recovery method and a transition metal recovery device that can recover a transition metal from a fuel cell without disassembling the fuel cell.

FIG. 1 is a schematic diagram schematically showing a fuel cell used in a transition metal recovery method and a recovery device according to a first embodiment. It is the schematic which shows the collection | recovery apparatus of the transition metal of 1st Embodiment typically. It is the schematic which shows typically the flow of the solution in the collection | recovery apparatus of the transition metal of 1st Embodiment. It is the schematic which shows the collection | recovery apparatus of the transition metal of 2nd Embodiment typically. It is the schematic which shows typically the flow of the solution in the recovery apparatus of the transition metal of 2nd Embodiment.

  Hereinafter, embodiments will be described with reference to the drawings.

(First Embodiment)
First, a fuel cell used in the transition metal recovery method and the recovery apparatus according to the first embodiment will be described. FIG. 1 is a schematic diagram schematically showing a fuel cell used in the transition metal recovery method and the recovery apparatus according to the first embodiment.

  The fuel cell 20 is a polymer electrolyte fuel cell (PEFC). As shown in FIG. 1, the fuel cell 20 includes a membrane electrode assembly (MEA) 80 as an electrode material. The MEA 80 is configured by stacking a fuel electrode (negative electrode) 50 having a diffusion layer, an air electrode (positive electrode) 60, an electrolyte membrane 70 made of an electrolyte material such as a fluoropolymer such as perfluorosulfonic acid, and the like. . The fuel electrode 50 and the air electrode 60 each include a catalyst component. Further, the diffusion layers included in the fuel electrode 50 and the air electrode 60 are made of a carbon-based material such as carbon paper or carbon cloth.

  Unless otherwise specified, hereinafter, a case will be described where the MEA 80 is a single cell including one of the anodes 50, one of the cathodes 60, and the electrolyte membrane 70 interposed between the anode 50 and the cathode 60. , MEA 80 may be a cell stack configured by stacking a plurality of single cells.

  Here, an example in which the fuel cell is a PEFC will be described. However, the fuel cell may be any fuel cell including an MEA such as a direct methanol fuel cell (DMFC).

  The fuel electrode 50 and the air electrode 60 that constitute the MEA 80 carry a catalyst component. The catalyst component is composed of a transition metal or the like. The form of such a catalyst component is not particularly limited, and examples thereof include a single transition metal, a compound containing a transition metal, and an alloy containing a transition metal. The transition metal constituting the catalyst component includes at least one metal selected from the group consisting of Pt (platinum), Ru (ruthenium), and Co (cobalt).

  As shown in FIG. 1, a fuel electrode flow path inlet 5a for supplying a fuel gas to the fuel cell 20 and a fuel electrode flow path for discharging the fuel gas from the fuel cell 20 are provided on the fuel electrode 50 side of the fuel cell 20. An outlet 5b is provided. The fuel gas is gaseous hydrogen (hereinafter also referred to as hydrogen gas). Further, an air electrode channel inlet 6a for supplying air to the fuel cell 20 and an air electrode channel outlet 6b for discharging air from the fuel cell 20 are provided on the air electrode 60 side.

  The fuel electrode flow path inlet 5a supplies hydrogen gas to the fuel electrode flow path of the fuel cell 20 when the fuel cell 20 is used, in other words, when power is generated by the fuel cell 20. Part. The fuel electrode channel outlet 5b is a portion where hydrogen gas was discharged from the fuel electrode channel when the fuel cell 20 was used. The number of the fuel electrode flow channel inlets 5a and the fuel electrode flow channel outlets 5b is not particularly limited, and may be one or more, respectively.

  The fuel electrode flow channel described later is provided inside the fuel cell 20 and communicates with a portion of the fuel electrode 50 containing a catalyst component. Further, when the fuel cell 20 is used, hydrogen gas, which is the fuel of the fuel cell 20, flows in the fuel electrode flow path. Then, part of the hydrogen gas supplied from the fuel electrode flow path inlet 5a to the fuel electrode flow path reacts with the catalyst component attached to the fuel electrode 50, and the remainder of the hydrogen gas flows to the fuel electrode flow path outlet. 5b.

  Further, the air electrode channel inlet 6a is a portion that supplies air to the air electrode channel of the fuel cell 20 when the fuel cell 20 is used. Further, the air electrode channel outlet 6b is a portion where air was discharged from the air electrode channel when the fuel cell 20 was used. Like the fuel electrode channel inlet 5a and the fuel electrode channel outlet 5b, the numbers of the air electrode channel inlets 6a and the air electrode channel outlets 6b are not particularly limited.

  An air electrode flow path described later is provided inside the fuel cell 20 and communicates with a portion of the air electrode 60 containing a catalyst component. Further, the air electrode flow path is not communicated with the fuel electrode flow path inside the fuel cell 20 and is independent. When the fuel cell 20 is used, air containing oxygen, which is the fuel of the fuel cell 20, flows in the air electrode flow path. Then, a part of the oxygen in the air supplied to the air electrode channel from the air electrode channel inlet 6a reacts with the catalyst component attached to the air electrode 60, and the rest of the air is supplied to the air electrode channel. It is discharged from the outlet 6b.

  Examples of the fuel cell 20 include a used fuel cell, that is, a discarded fuel cell.

  Next, a method for recovering transition metals according to the first embodiment will be described.

  The transition metal recovery method according to the first embodiment includes a fuel electrode immersion step S10, an air electrode immersion step S20, a melting step S30, a fuel electrode discharge step S40, and an air electrode discharge step S50. In the transition metal recovery method according to the first embodiment, all the steps are performed in a state where the MEA is provided inside the fuel cell, that is, without disassembling the fuel cell.

  First, the fuel electrode immersion step S10 will be described.

  In the fuel electrode immersion step S10, a solution is supplied to the fuel electrode channel inlet or the fuel electrode channel outlet, and the fuel electrode is immersed in the solution. Hereinafter, the fuel electrode immersion step S10 of supplying a solution to the fuel electrode channel inlet will be described. However, the solution may be supplied to the fuel electrode channel outlet in the fuel electrode immersion step.

  In the fuel electrode immersion step S10, the solution is supplied from the outside of the fuel cell to the fuel electrode channel inlet, so that the solution flows in the fuel electrode channel, and the fuel electrode is immersed in the solution. Here, if the portion containing the catalyst component in the fuel electrode is immersed in the solution, a part of the fuel electrode may be immersed in the solution, or all of the fuel electrode may be immersed in the solution. You may.

  In the anode immersion step S10, the method of supplying the solution to the inlet of the anode channel is not particularly limited. For example, a supply pump may be connected to the fuel electrode flow channel inlet, and the supply pump may supply the dissolved liquid from the fuel electrode flow channel inlet to the fuel electrode flow channel. Alternatively, a suction pump may be connected to the outlet of the anode flow path, and the solution may be supplied from the inlet of the anode flow path to the anode flow path by a suction pump that discharges the solution from the outlet of the anode flow path.

  In the fuel electrode immersion step S10, the solution may be supplied continuously, or may be supplied intermittently at predetermined time intervals at predetermined time intervals. When the solution is supplied intermittently, the supply time of the solution and the time interval of the supply time may be all the same or partially different.

  The lysate contains halide ions such as chloride ions and is acidic. Further, the solution dissolves the transition metal contained in the fuel cell. The type of halide ions contained in the solution supplied to the fuel electrode channel inlet is appropriately selected according to the type of transition metal contained in the fuel electrode. Further, the solution may include an anion exchange resin. When the solution contains an anion exchange resin, the solution is a solid-liquid mixture in which the anion exchange resin is dispersed.

  The concentration of halide ions in the solution is preferably 0.01 mol / L or more and 16.0 mol / L or less. When the concentration of the halide ions in the solution is 0.01 mol / L or more, the transition metal can be easily dissolved in the solution in the dissolution step S30 described below. When the halide ion concentration is 16.0 mol / L or less, it is possible to reduce the amount of halide ions consumed in the electrolysis by applying a voltage in the dissolving step S30.

  Here, in the dissolving step S30 described later, the concentration of the halide ions in the solution decreases with the reaction between the transition metal contained in the fuel cell and the halide ions in the solution. Therefore, unless otherwise specified, the concentration of the halide ion in the solution indicates the concentration of the halide ion in the solution in the fuel electrode immersion step S10.

  The pH of the solution is preferably 5 or less, more preferably 3 or less. When the pH of the solution is 5 or less, in the dissolution step S30, the transition metal is easily dissolved in the solution. On the other hand, if the pH of the solution is higher than 5, it is not easy to dissolve the transition metal in the solution in the dissolution step S30.

  Next, the air electrode immersion step S20 will be described.

  In the air electrode immersion step S20, the solution is supplied to the air electrode channel inlet or the air electrode channel outlet, and the air electrode is immersed in the solution. Hereinafter, the air electrode immersion step S20 of supplying a solution to the air electrode channel inlet will be described, but the air electrode immersion step may supply the solution to the air electrode channel outlet.

  In the air electrode immersion step S20, the solution is supplied from outside the fuel cell to the inlet of the air electrode channel, so that the solution flows in the air electrode channel, and the air electrode is immersed in the solution. As in the fuel electrode immersion step S10, if the portion containing the catalyst component in the air electrode is immersed in the solution, part of the air electrode may be immersed in the solution, or all of the air electrode may be immersed in the solution. May be immersed in the solution. The type of halide ions contained in the solution to be supplied to the inlet of the air electrode channel is appropriately selected according to the type of transition metal contained in the air electrode.

  In the air electrode immersion step S20, the method of supplying the solution to the air electrode channel inlet is not particularly limited. For example, as in the fuel electrode immersion step S10, the supply liquid is supplied from the air electrode channel inlet to the air electrode channel by a supply pump connected to the air electrode channel inlet or a suction pump connected to the air electrode channel outlet. May be.

  Further, in the air electrode immersion step S20, similarly to the fuel electrode immersion step S10, the solution may be supplied continuously, or may be supplied intermittently at predetermined time intervals at predetermined time intervals. Is also good.

  The air electrode immersion step S20 may be performed after the fuel electrode immersion step S10 is completed, may be performed before the fuel electrode immersion step S10 is performed, or may be performed simultaneously with the fuel electrode immersion step S10. Is also good.

  Next, the dissolving step S30 will be described.

  In the dissolving step S30, a voltage is applied from outside the fuel cell to the fuel electrode and the air electrode immersed in the solution via the fuel electrode output terminal and the air electrode output terminal of the fuel cell, and The transition metal contained in the air electrode is dissolved in the solution. The voltage applied to the fuel electrode and the air electrode may be a DC voltage or an AC voltage.

  The fuel electrode output terminal is electrically connected to the fuel electrode. The air electrode output terminal is electrically connected to the air electrode. The fuel electrode output terminal and the air electrode output terminal are terminals that output generated power to the outside when the fuel cell is used.

  When a voltage is applied to the fuel electrode and the air electrode, the transition metal is dissolved in the solution from the portions of the fuel electrode and the air electrode that are immersed in the solution. Thus, the transition metal in the fuel electrode and the air electrode is recovered in the solution. The form of the transition metal dissolved in the solution is a complex ion (hereinafter, also referred to as a transition metal complex ion).

  In the dissolving step S30, the voltage applied to the fuel electrode and the air electrode is appropriately set according to the type and number of MEAs provided in the fuel cell and the type of the dissolving solution. For one MEA having an electrolyte membrane sandwiched between a fuel electrode and an air electrode, the voltage is preferably 0.10 V or more and 3.00 V or less, more preferably 0.70 V or more and 2.50 V or less, and more preferably 0.10 V or more and 2.50 V or less. More preferably, it is 75 V or more and 2.00 V or less. When the voltage applied to the fuel electrode and the air electrode is equal to or higher than the above lower limit, the transition metal contained in the fuel electrode and the air electrode is easily dissolved in the solution. Further, when the voltage is equal to or lower than the above upper limit, it is possible to reduce a side reaction generated at the time of dissolution.

  For example, when the fuel electrode and the air electrode contain platinum and the solution contains chloride ions, when a predetermined voltage is applied to the fuel electrode and the air electrode immersed in the solution, the following formula (1) is obtained. ) And formula (2) occur, and a platinum complex ion is easily generated. The details are as follows.

Equation (1) is a reversible reaction. When a predetermined voltage is applied to the fuel electrode and the air electrode, the reaction from left to right in equation (1) proceeds. That is, platinum as a transition metal reacts with chloride ion as a halide ion to generate tetrachloroplatinate (II) ion ([PtCl ₄ ] ²⁻ ) as a platinum complex ion.

Equation (2) is also a reversible reaction. When a voltage larger than that in the case of the equation (1) is applied to the fuel electrode and the air electrode, a reaction from left to right in the equation (2) proceeds. That is, platinum and a chloride ion reacts, a platinum complex ion hexachloroplatinic (IV) acid ion ([PtCl _6] ^2-) is generated.

  Thus, the platinum contained in the fuel electrode and the air electrode dissolves in the solution as platinum complex ions. When the solution contains an anion exchange resin, platinum is dissolved in the solution while the platinum complex ions in the solution are collected by the anion exchange resin.

  The dissolving step S30 may be performed after the fuel electrode dipping step S10 and the air electrode dipping step S20 are completed, or may be performed together with the fuel electrode dipping step S10 and the air electrode dipping step S20.

  Next, the fuel electrode discharging step S40 will be described.

  In the fuel electrode discharging step S40, the solution containing the transition metal is discharged from the fuel electrode channel outlet or the fuel electrode channel inlet.

  In the fuel electrode discharging step S40, the solution containing the transition metal contained in the fuel electrode of the fuel cell is discharged to the outside of the fuel cell by discharging the solution containing the transition metal from the fuel electrode channel outlet. . As a result, the transition metal contained in the fuel cell is recovered from inside the fuel cell.

  Here, the fuel electrode discharging step S40 for discharging the solution from the fuel electrode channel outlet will be described. However, the solution may be discharged from the fuel electrode channel inlet in the fuel electrode discharging step. Specifically, when the solution is supplied to the fuel electrode channel inlet in the fuel electrode immersion step S10, the solution is discharged from the fuel electrode channel outlet in the fuel electrode discharging step. When the solution is supplied to the outlet of the fuel electrode flow channel in the fuel electrode immersion step S10, the solution is discharged from the fuel electrode flow channel inlet in the fuel electrode discharge step.

  In the anode discharging step S40, the method of discharging the solution from the outlet of the anode channel is not particularly limited. For example, the solution may be discharged from the fuel electrode flow path via the fuel electrode flow path outlet by the supply pump or the suction pump used in the fuel electrode immersion step S10.

  In the fuel electrode discharging step S40, the solution may be continuously discharged, or may be discharged intermittently at predetermined time intervals at predetermined time intervals. When the solution is discharged intermittently, the discharge time of the solution and the time interval of the discharge time may be all the same or may be partially different.

  Further, the fuel electrode discharging step S40 may be performed after the completion of the melting step S30, or may be performed together with the melting step S30.

  Further, a part or all of the solution discharged from the fuel cell in the fuel electrode discharging step S40 may be used as a solution to be supplied to the fuel cell in the fuel electrode immersion step S10. In this case, for example, a connecting channel connecting the fuel electrode channel outlet and the fuel electrode channel inlet is provided outside the fuel cell, and the solution is circulated in the fuel electrode channel and the connecting channel.

  Specifically, when the solution is discharged from the fuel electrode channel outlet in the fuel electrode discharging step S40, the solution may be supplied to the fuel electrode channel inlet in the fuel electrode dipping step S10. Further, when the solution is discharged from the fuel electrode channel inlet in the fuel electrode discharging step S40, the solution may be supplied to the fuel electrode channel outlet in the fuel electrode dipping step S10.

  Next, the air electrode discharging step S50 will be described.

  In the cathode discharge step S50, the solution containing the transition metal is discharged from the cathode passage outlet or the cathode inlet.

  In the air electrode discharging step S50, the solution containing the transition metal contained in the air electrode is discharged from the fuel cell by discharging the solution containing the transition metal from the air electrode channel outlet. As a result, the transition metal contained in the fuel cell is recovered from inside the fuel cell.

  Here, the cathode discharge step S50 for discharging the solution from the cathode passage outlet will be described. However, the cathode discharge step may discharge the solution from the cathode inlet. Specifically, when the solution is supplied to the air electrode channel inlet in the air electrode immersion step S20, the solution is discharged from the air electrode channel outlet in the air electrode discharging step. In addition, when the solution is supplied to the outlet of the air electrode channel in the air electrode immersion step S20, the solution is discharged from the air electrode channel inlet in the air electrode discharging step.

  In the air electrode discharging step S50, the method of discharging the solution from the air electrode channel outlet is not particularly limited. For example, similarly to the fuel electrode discharge step S40, the supply liquid or the suction pump used in the air electrode immersion step S20 may discharge the solution from the air electrode flow path through the air electrode flow path outlet.

  Further, in the air electrode discharging step S50, similarly to the fuel electrode discharging step S40, the solution may be continuously discharged, or may be discharged intermittently at predetermined time intervals at predetermined time intervals. Is also good.

  The cathode discharge step S50 may be performed after the anode discharge step S40 is completed, may be performed before the anode discharge step S40, or may be performed simultaneously with the anode discharge step S40. Is also good. Further, the air electrode discharging step S50 may be performed after completion of the dissolving step S30, or may be performed together with the dissolving step S30.

  In addition, a part or all of the solution discharged from the fuel cell in the cathode discharge step S50 may be used as a solution to be supplied to the fuel cell in the cathode immersion step S20. In this case, for example, similarly to the fuel electrode discharging step S40, a connection flow path that connects the air electrode flow path outlet and the air electrode flow path inlet is provided, and the solution is circulated.

  Specifically, when the solution is discharged from the air electrode channel outlet in the air electrode discharging step S50, the solution may be supplied to the air electrode channel inlet in the air electrode immersion step S20. Further, when the solution is discharged from the inlet of the air electrode channel in the air electrode discharging step S50, the solution may be supplied to the outlet of the air electrode channel in the air electrode immersion step S20.

  As described above, in the transition metal recovery method of the first embodiment, the solution is separately supplied and discharged to the fuel electrode channel and the air electrode channel which are independent of each other. Therefore, when the transition metal contained in the anode and the transition metal contained in the cathode are different, the solution supplied to the anode channel and the solution supplied to the cathode channel are different from each other, It is appropriately selected according to the type of metal. When the transition metal contained in the fuel electrode and the transition metal contained in the air electrode are the same, the solution supplied to the fuel electrode flow path and the solution supplied to the air electrode flow path are basically Is the same.

  In the transition metal recovery method, the solution is separately discharged from the fuel electrode flow path and the air electrode flow path that are independent of each other. If the transition metal contained in the anode and the transition metal contained in the air electrode are different, the transition metal contained in the solution discharged from the anode flow path and the transition metal contained in the solution discharged from the air flow path Different from metal. When the solution is discharged, the solution discharged from the fuel electrode channel and the solution discharged from the air electrode channel do not mix with each other, so that the processing steps performed on the solution for the reuse of the transition metal are easy. become.

  In the dissolving step S30, gas is generated when the transition metal dissolves in the dissolving solution. The generated gas flows through the fuel electrode flow path and the air electrode flow path together with the solution, and is discharged from the fuel electrode flow path outlet and the air electrode flow path outlet to the outside of the fuel cell. On the other hand, when gas accumulates in the fuel electrode flow path or the air electrode flow path, the portion of the fuel electrode or the air electrode immersed in the solution decreases. Therefore, the amount of the transition metal dissolved in the solution decreases. Here, in the transition metal recovery method of the first embodiment, the dissolved liquid is separately discharged from the fuel electrode flow path and the air electrode flow path. It is quickly discharged from the fuel electrode flow path and the air electrode flow path without excessive accumulation in the passage and the air flow path. Therefore, a decrease in the amount of transition metal dissolved due to a decrease in the portion of the fuel electrode or the air electrode immersed in the solution is suppressed.

  Further, the transition metal can be recovered from the inside of the fuel cell without burning the MEA. Therefore, the generation of harmful substances derived from the fluoropolymer contained in the MEA, which is generated when the MEA is incinerated, is avoided.

  Further, the transition metal recovery method of the first embodiment may further include a supply step S60 and a discharge step S70. The supply step S60 and the discharge step S70 are performed without dismantling the fuel cell.

  In the supply step S60, the solution is supplied to a cooling water flow path inlet for supplying cooling water to the fuel cell or a cooling water flow path outlet for discharging cooling water from the fuel cell. Hereinafter, the supply step S60 of supplying the solution to the cooling water channel inlet will be described, but the solution may be supplied to the cooling water channel outlet in the supplying step.

  The cooling water flow path inlet is a portion where the cooling water was supplied to the cooling water flow path of the fuel cell when the fuel cell was used. The cooling water flow path outlet is a part where the cooling water was discharged from the cooling water flow path when the fuel cell was used. The number of cooling water passage inlets and cooling water passage outlets is not particularly limited.

  The cooling water passage is provided inside the fuel cell. Further, inside the fuel cell, the cooling water flow path does not communicate with the fuel electrode flow path and the air electrode flow path and is independent. Further, when the fuel cell is used, cooling water flows in the cooling water channel. Then, the cooling water supplied from the cooling water flow path inlet to the cooling water flow path is discharged from the cooling water flow path outlet while cooling a portion heated during power generation of the fuel cell. The number of cooling water channels provided is not particularly limited.

  In the supply step S60, the solution is supplied from the outside of the fuel cell to the inlet of the cooling water channel, so that the solution flows in the cooling water channel. The solution flowing in the cooling water flow path cools a portion heated during dissolution of the transition metal in the dissolving step S30. Therefore, the temperature distribution in the fuel cell is reduced, and in the melting step S30, the variation in the dissolution of the transition metal due to the temperature distribution in the fuel cell is suppressed. If the cooling water remains in the cooling water channel, the cooling water is discharged from the fuel cell before performing the supplying step S60.

  In the supply step S60, the method for supplying the solution to the inlet of the cooling water channel is not particularly limited. For example, similarly to the fuel electrode immersion step S10, the solution may be supplied from the cooling water channel inlet to the cooling water channel by a supply pump connected to the cooling water channel inlet or a suction pump connected to the cooling water channel outlet. .

  Further, in the supply step S60, similarly to the fuel electrode immersion step S10, the solution may be supplied continuously, or may be supplied intermittently at predetermined time intervals at predetermined time intervals. .

  Further, the timing for performing the supply step S60 is not particularly limited. For example, when the temperature of the fuel cell becomes equal to or higher than a predetermined temperature in the melting step S30, the supplying step S60 is performed.

  In the supply step S60, the dissolved liquid supplied to the fuel electrode flow path inlet in the fuel electrode immersion step S10 may be supplied to the cooling water flow path entrance, or may be supplied to the air electrode flow path entrance in the air electrode immersion step S20. The dissolved solution to be used may be supplied to the cooling water channel inlet, or a solution not used in the fuel electrode immersion step S10 and the air electrode immersing step S20 may be supplied to the cooling water channel inlet.

  In the discharging step S70, the solution is discharged from the cooling water flow path outlet or the cooling water flow path inlet to the outside of the fuel cell. In the discharging step S70, the heat generated at the time of dissolving the transition metal is easily taken out of the fuel cell through the liquid by discharging the dissolved liquid from the cooling water flow path outlet.

  Here, the discharging step S70 for discharging the dissolved liquid from the cooling water flow path outlet will be described. However, when the dissolving liquid is supplied to the cooling water flow path outlet in the supplying step S60, the dissolving is performed from the cooling water flow path inlet in the discharging step. Drain the liquid.

  In the discharging step S70, the method of discharging the solution from the outlet of the cooling water channel is not particularly limited. For example, similarly to the fuel electrode discharging step S40, the solution may be discharged from the cooling water flow path via the cooling water flow path outlet by the supply pump or the suction pump used in the supply step S60.

  In the discharging step S70, similarly to the fuel electrode discharging step S40, the solution may be continuously discharged, or may be discharged intermittently at predetermined time intervals at predetermined time intervals. .

  Further, the discharging step S70 may be performed after the completion of the supplying step S60, or may be performed together with the supplying step S60.

  Further, a part or all of the solution discharged from the cooling water channel in the discharging step S70 may be used for the solution to be supplied to the cooling water channel in the supplying step S60, or the fuel electrode channel may be used in the fuel electrode dipping step S10. May be used for the dissolving liquid supplied to the air electrode or may be used for the dissolving liquid supplied to the air electrode channel in the air electrode immersion step S20. In this case, for example, similarly to the fuel electrode discharging step S40, a connection flow path connecting the cooling water flow path outlet and the cooling water flow path inlet, a connection flow path connecting the cooling water flow path outlet and the fuel electrode flow path inlet, A connecting flow path is provided for connecting the water flow path outlet and the air electrode flow path inlet, and the solution is circulated in these flow paths.

  For example, when the solution is discharged from the outlet of the cooling water channel in the discharging step S70, the solution may be supplied to the inlet of the cooling water channel in the supplying step S60, or may be supplied to the fuel electrode immersion step S10. The air may be supplied to the entrance of the passage, or may be supplied to the entrance of the cathode passage in the cathode immersion step S20. When the solution is discharged from the cooling water channel inlet in the discharging step S70, the solution may be supplied to the cooling water channel outlet in the supplying step S60, or the fuel electrode flow may be supplied in the fuel electrode dipping step S10. The air may be supplied to the air outlet, or may be supplied to the air electrode flow channel outlet in the air electrode immersion step S20.

  Next, a transition metal recovery device according to the first embodiment will be described.

  FIG. 2 is a schematic diagram schematically showing the transition metal recovery device 1 of the first embodiment. FIG. 3 is a schematic diagram schematically showing the flow of the solution in the transition metal recovery device 1 according to the first embodiment. The transition metal recovery apparatus 1 (hereinafter, also simply referred to as the recovery apparatus 1) is an apparatus that can perform the transition metal recovery method of the first embodiment described above. In FIG. 3, the flow of the solution during recovery of the transition metal is indicated by arrows.

  As shown in FIG. 2, the recovery device 1 supplies a solution to the inside of the fuel cell 2 and immerses the solution in a solution supply unit 3 for discharging the supplied solution to the outside of the fuel cell 2. And a voltage application unit 4 for applying a voltage to the fuel electrode and the air electrode (not shown).

  The solution supply unit 3 has a first supply unit 3a and a second supply unit 3b. As shown in FIG. 3, the first supply unit 3a supplies a solution to the fuel electrode channel inlet 5a, and discharges the solution from the fuel electrode channel outlet 5b. The dissolved liquid supplied to the fuel electrode flow path inlet 5a flows through the fuel electrode flow path 5 and immerses the fuel electrode. The second supply unit 3b supplies the solution to the air electrode channel inlet 6a, and discharges the solution from the air electrode channel outlet 6b. The lysing solution supplied to the air electrode channel inlet 6a flows through the air electrode channel 6 to immerse the air electrode. For example, the first supply unit 3a and the second supply unit 3b include a supply pump.

  As shown in FIG. 3, the recovery device 1 separately supplies and discharges the solution to and from the fuel electrode channel 5 and the air electrode channel 6, which are independent of each other. In other words, the first supply unit 3a and the second supply unit 3b are driven separately from each other. The type of the solution supplied from the first supply unit 3a to the fuel electrode flow path 5 is appropriately selected according to the type of the transition metal contained in the fuel electrode. Further, the type of the solution supplied from the second supply unit 3b to the air electrode channel 6 is appropriately selected according to the type of the transition metal contained in the air electrode.

  As shown in FIG. 3, here, the solution is provided inside the fuel cell 2, and through a flow path 15 a connecting the first supply unit 3 a and the fuel electrode flow path inlet 5 a, the dissolved liquid is supplied to the fuel electrode flow path inlet. Although an example of supplying the solution to the fuel electrode 5a will be described, the solution may be supplied to the fuel electrode channel inlet 5a without passing through the channel 15a. Similarly, the solution to be supplied to the air electrode flow path 6 may be supplied to the air electrode flow path inlet 6a via a flow path 16a provided inside the fuel cell 2, or may be supplied through the flow path 16a. Alternatively, the air may be supplied to the air electrode channel inlet 6a.

  Similarly, an example in which the solution supplied to the fuel electrode flow path 5 is discharged from the fuel electrode flow path outlet 5b to the outside of the fuel cell 2 via the flow path 15b provided inside the fuel cell 2 will be described. However, the solution may be discharged from the fuel electrode channel outlet 5b to the outside of the fuel cell 2 without passing through the channel 15b. The dissolved liquid supplied to the air electrode flow path 6 may also be discharged from the air electrode flow path outlet 6b to the outside of the fuel cell 2 via the flow path 16b, or may be discharged without passing through the flow path 16b. The fuel may be discharged to the outside of the fuel cell 2 from the road exit 6b.

  Note that the channels 15a, 15b, 16a, 16b are not provided for recovering transition metals, but are already provided inside the fuel cell 2.

  As shown in FIG. 3, the channel 15a, the fuel electrode channel 5, and the channel 15b are a series of communicating channels. The flow path 16a, the air electrode flow path 6, and the flow path 16b are a series of communicating paths, and the flow path 15a, the fuel electrode flow path 5, and the flow path 15b are inside the fuel cell 2. Independent, not in communication.

  Here, the first supply unit 3a for supplying the solution to the fuel electrode channel inlet 5a and the second supply unit 3b for supplying the solution to the air electrode channel inlet 6a will be described. May supply the solution to the fuel electrode channel outlet 5b and discharge the solution from the fuel electrode channel inlet 5a, or the second supply unit 3b may supply the solution to the air electrode channel outlet 6b. The solution may be supplied to discharge the solution from the air electrode channel inlet 6a. In other words, the flow direction of the solution in FIG. 3 is not particularly limited.

  As shown in FIG. 2, the voltage applying unit 4 is connected via a fuel electrode output terminal 7 electrically connected to a fuel electrode (not shown) and an air electrode output terminal 8 electrically connected to an air electrode (not shown). Then, a predetermined voltage is applied to the fuel electrode and the air electrode immersed in the solution from outside the fuel cell 2. The voltage applied from the voltage application unit 4 to the fuel electrode and the air electrode may be a DC voltage or an AC voltage.

  When a voltage is applied to the fuel electrode and the air electrode from the voltage applying unit 4, the transition metal contained in the fuel electrode is dissolved in the solution as a transition metal complex ion in the fuel electrode channel 5, and The transition metal contained in the air electrode dissolves in the solution as a transition metal complex ion. Then, the solution containing the transition metal carried on the fuel electrode is discharged from the fuel electrode channel outlet 5b to the outside of the fuel cell 2 by the first supply unit 3a. Further, the solution containing the transition metal carried on the air electrode is discharged from the air electrode channel outlet 6b to the outside of the fuel cell 2 by the second supply unit 3b. Thus, the transition metal contained in the fuel cell 2 is recovered from inside the fuel cell 2.

  When recovering the transition metal from the fuel cell 2, the first supply unit 3 a and the second supply unit 3 b supply the solution inside the fuel cell 2 without disassembling the fuel cell 2, The solution is discharged to the outside, and the voltage application unit 4 applies a voltage to the fuel electrode and the air electrode from outside the fuel cell 2. Further, the first supply unit 3a may circulate the solution in the recovery device 1 until the recovery of the transition metal from the fuel electrode is completed, or the second supply unit 3b may transmit the dissolved metal from the air electrode. The solution may be circulated in the collection device 1 until the collection of the solution is completed.

  As shown in FIG. 3, the recovery device 1 is connected to the first tank 9a connected to the fuel electrode channel outlet 5b and the first supply unit 3a, and connected to the air electrode channel outlet 6b and the second supply unit 3b. A second tank 9b and an exhaust unit 10 connected to the first tank 9a and the second tank 9b.

  The solution discharged from the fuel electrode channel outlet 5b of the fuel cell 2 is supplied to the first tank 9a. The first tank section 9a separates a liquid phase composed of a solution containing a transition metal and a gas phase composed of gases such as hydrogen, chlorine, and oxygen contained in the solution, and separates the liquid phase and the gas phase. To store. The gaseous phase part is stored in the upper part in the first tank portion 9a, and the liquid phase part is stored below the gaseous phase part. The gas phase portion in the first tank unit 9a is supplied to the exhaust unit 10, and the exhaust unit 10 exhausts the gas supplied from the first tank unit 9a to the outside of the recovery device 1. The solution, which is a liquid phase portion in the first tank portion 9a, is supplied by the first supply portion 3a to the fuel electrode channel inlet 5a and a cooling water channel inlet 11a described later.

  Similarly, the dissolved liquid discharged from the air electrode channel outlet 6b is supplied to the second tank unit 9b. The second tank section 9b stores a liquid phase composed of a solution containing a transition metal and a gas phase composed of a gas contained in the solution. The gas phase portion in the second tank unit 9b is supplied to the exhaust unit 10, and the exhaust unit 10 exhausts the gas supplied from the second tank unit 9b to the outside of the recovery device 1. The solution, which is a liquid phase portion in the second tank portion 9b, is supplied to the air electrode channel inlet 6a by the second supply portion 3b.

  Further, as shown in FIG. 3, in the recovery device 1, the first supply unit 3 a may supply the solution to the cooling water channel inlet 11 a and discharge the solution from the cooling water channel outlet 11 b.

  When the solution is supplied from the first supply unit 3a to the cooling water channel 11 via the cooling water channel inlet 11a, the portion of the fuel cell 2 that is heated when the transition metal is melted is cooled by the solution. Therefore, the temperature distribution in the fuel cell 2 is reduced, and the stabilized transition metal can be recovered.

  As in the case of recovering the transition metal from the fuel cell 2, the first supply unit 3 a supplies the dissolved liquid to the cooling water channel 11 provided inside the fuel cell 2 without disassembling the fuel cell 2. Then, the solution is discharged from the cooling water channel 11.

  Similarly to the solution supplied to the fuel electrode flow path 5 and the air electrode flow path 6, the solution supplied to the cooling water flow path 11 is supplied to the cooling water flow path 17a through the flow path 17a provided inside the fuel cell 2. The cooling water may be supplied to the inlet 11a or may be supplied to the cooling water passage inlet 11a without passing through the passage 17a. Similarly, the solution supplied to the cooling water flow path 11 may be discharged to the outside of the fuel cell 2 via the flow path 17b, or may be discharged to the outside of the fuel cell 2 without passing through the flow path 17b. Is also good. The channels 17a and 17b are not provided for recovering transition metals, but are already provided inside the fuel cell 2.

  The flow path 17a, the cooling water flow path 11, and the flow path 17b are a series of communicating paths, and inside the fuel cell 2, the flow path 15a, the fuel electrode flow path 5, the flow path 15b, and the flow path The passage 16a, the air electrode passage 6, and the passage 16b are independent of each other without communication.

  Here, the first supply unit 3a that supplies the solution to the cooling water channel inlet 11a will be described. However, the first supply unit 3a supplies the solution to the cooling water channel outlet 11b and the cooling water channel inlet 11a. The solution may be discharged from 11a. Further, although the first supply unit 3a supplies the solution to the cooling water channel 11, the second supply unit 3b may supply the solution to the cooling water channel 11 instead of the first supply unit 3a. Alternatively, a dissolving solution supply unit (not shown) different from the dissolving solution supply unit 3 may supply the dissolving solution to the cooling water channel 11.

  Here, an example in which one cooling water flow path 11 is provided in the vicinity of the fuel electrode flow path 5 opposite to the air electrode flow path 6 will be described, but the installation position of the cooling water flow path 11 is particularly limited. Instead, a plurality of cooling water passages 11 may be provided in the fuel cell 2. When two cooling water flow paths are provided in the fuel cell 2, for example, one of the cooling water flow paths is provided near the fuel electrode flow path 5 opposite to the air electrode flow path 6 side, and the other of the cooling water flow paths is provided. It is provided in the vicinity of the air electrode channel 6 on the side opposite to the fuel electrode channel 5 side.

  After recovering the transition metal from the fuel electrode, the first supply unit 3a is stopped to stop the circulation of the solution. The transition metal in the solution is discharged from the first tank unit 9a to the outside of the recovery device 1 through a drain port (not shown) provided in the first tank unit 9a, for example. Similarly, after recovering the transition metal from the air electrode, the second supply unit 3b is stopped to stop the circulation of the solution. The transition metal in the solution is discharged to the outside of the recovery device 1 via, for example, a drain port (not shown) provided in the second tank portion 9b.

  The fuel cell 2 from which the transition metal has been recovered is replaced with, for example, a fuel cell from which the transition metal has not been recovered.

  As described above, according to the transition metal recovery method and the transition metal recovery device of the first embodiment, the fuel electrode provided inside the fuel cell is added to the solution supplied from outside the fuel cell. And, by applying a voltage from outside the fuel cell to the fuel electrode and the air electrode immersed in the solution, the transition metals contained in the fuel electrode and the air electrode are immersed in the solution. Can be dissolved. Then, the solution containing the transition metal can be discharged to the outside of the fuel cell. Therefore, the transition metal can be easily recovered from the inside of the fuel cell without disassembling the fuel cell.

  Further, the solution can be separately supplied and discharged to the fuel electrode flow path and the air electrode flow path which are independent from each other. Therefore, the type of solution for immersing the fuel electrode and the type of solution for immersing the air electrode can be appropriately selected according to the type of transition metal contained in the fuel electrode and the air electrode.

  Further, the solution is separately discharged from the fuel electrode channel and the air electrode channel which are independent of each other. When the transition metal contained in the dissolved liquid discharged from the fuel electrode flow path and the transition metal contained in the dissolved liquid discharged from the air electrode flow path are different, these dissolved liquids are separately discharged without being mixed with each other. Therefore, the type of transition metal contained in the solution does not increase, and the processing step for reusing the transition metal in the solution is facilitated.

  Further, gas generated at the fuel electrode or the air electrode in the dissolving step is quickly discharged from the fuel electrode channel or the air electrode channel together with the solution. Therefore, a decrease in the portion of the fuel electrode or the air electrode immersed in the solution is suppressed, and a decrease in the amount of transition metal dissolved is suppressed.

(Second embodiment)
The transition metal recovery method of the second embodiment is the same as the first embodiment except that the configurations of the anode immersion step S110, the cathode immersion step S120, the anode discharge step S140, and the cathode discharge step S150 are different. The configuration is basically the same as that of the method for recovering the transition metal in the form.

  FIG. 4 is a schematic diagram schematically showing a transition metal recovery device 31 according to the second embodiment. FIG. 5 is a schematic diagram schematically showing the flow of the solution in the transition metal recovery device 31 according to the second embodiment. The transition metal recovery device 31 of the second embodiment is basically the same as the transition metal recovery device 1 of the first embodiment, except that the configurations of a solution supply unit 33 and a tank unit 39 are different. Is the same.

  In the embodiments described below, descriptions overlapping with the configuration of the first embodiment will be omitted or simplified. Then, a configuration different from the configuration of the first embodiment will be mainly described.

  First, a transition metal recovery method according to the second embodiment will be described.

  The transition metal recovery method according to the second embodiment includes a fuel electrode dipping step S110, an air electrode dipping step S120, a melting step S30, a fuel electrode discharging step S140, and an air electrode discharging step S150. In the transition metal recovery method according to the second embodiment, the same solution is supplied and discharged to the fuel electrode flow path and the air electrode flow path connected in series.

  The fuel electrode immersion step S110 will be described.

  In the fuel electrode immersion step S110, the solution is supplied to the fuel electrode channel inlet or the fuel electrode channel outlet, and the fuel electrode is immersed in the solution. In the same manner as in the fuel electrode immersion step S10, in the fuel electrode immersion step S110, the solution is supplied to the fuel electrode channel inlet or the fuel electrode channel outlet, so that the solution flows through the fuel electrode channel, Is immersed in the solution.

  In the fuel electrode immersion step S110, the solution discharged from the air electrode channel outlet or the air electrode channel inlet in the later-described air electrode discharge step S150 may be supplied to the fuel electrode channel inlet or the fuel electrode channel outlet. .

  Next, the air electrode immersion step S120 will be described.

  In the air electrode immersion step S120, the solution is supplied to the air electrode channel inlet or the air electrode channel outlet, and the air electrode is immersed in the solution. Similarly to the air electrode immersion step S20, in the air electrode immersion step S120, the solution is supplied to the air electrode channel inlet or the air electrode channel outlet, so that the solution flows through the air electrode channel, Is immersed in the solution.

  In the cathode immersion step S120, the dissolved liquid discharged from the anode flow path outlet or the anode flow path entrance in the later-described anode discharge step S140 may be supplied to the cathode flow path entrance or the cathode flow path exit. .

  Next, the dissolving step S30 will be described.

  In the dissolving step S30, a voltage is applied to the fuel electrode and the air electrode immersed in the dissolving solution supplied in the fuel electrode immersing step S110 and the air electrode immersing step S120 to dissolve transition metals contained in the fuel electrode and the air electrode. Dissolve in liquid.

  Next, the fuel electrode discharging step S140 will be described.

  In the fuel electrode discharging step S140, the solution containing the transition metal is discharged from the fuel electrode channel outlet or the fuel electrode channel inlet. Similarly to the fuel electrode discharging step S40, in the fuel electrode discharging step S140, the transition metal contained in the fuel electrode is discharged by discharging the solution containing the transition metal from the fuel electrode channel outlet or the fuel electrode channel inlet. The contained solution is recovered from inside the fuel cell.

  When the fuel electrode immersion step S110 is performed before the air electrode immersion step S120, the dissolved liquid discharged from the fuel electrode channel outlet or the fuel electrode channel inlet in the fuel electrode discharge step S140 is used as the air electrode immersion step S120. At the air electrode channel inlet or the air electrode channel outlet. When the anode immersion step S110 is performed after the cathode immersion step S120, part or all of the solution discharged in the anode discharge step S140 may be supplied to the cathode immersion step S120.

  Next, the air electrode discharging step S150 will be described.

  In the cathode discharge step S150, the solution containing the transition metal is discharged from the cathode outlet or the cathode inlet. Similarly to the cathode discharge step S50, in the cathode discharge step S150, the transition metal contained in the cathode is discharged by discharging the solution containing the transition metal from the cathode passage outlet or the cathode inlet. The contained solution is recovered from inside the fuel cell.

  Further, when the fuel electrode immersion step S110 is performed after the air electrode immersion step S120, the dissolved liquid discharged from the air electrode channel outlet or the air electrode channel inlet in the air electrode discharge step S150 is used in the fuel electrode immersion step S110. The fuel is supplied to the fuel electrode channel inlet or the fuel electrode channel outlet. Further, when the fuel electrode immersion step S110 is performed before the air electrode immersion step S120, a part or all of the solution discharged in the air electrode discharge step S150 may be supplied to the fuel electrode immersion step S110.

  Further, the transition metal recovery method according to the second embodiment may further include a supply step S160 and a discharge step S170.

  In the supply step S160, similarly to the supply step S60, the solution is supplied to the cooling water flow path inlet or the cooling water flow path outlet.

  When the supply step S160 is performed after the anode immersion step S110 and the cathode electrode immersion step S120, the solution discharged in the anode discharge step S140 and the cathode discharge step S150 is supplied to the supply step S160. Specifically, when the fuel electrode immersion step S110 is performed before the air electrode immersion step S120, the dissolved liquid discharged in the air electrode discharge step S150 is supplied to the cooling water channel inlet or the cooling water channel outlet in the supply step S160. Supply. When the fuel electrode immersion step S110 is performed after the air electrode immersion step S120, the solution discharged in the fuel electrode discharge step S140 is supplied to the supply step S160.

  When the supply step S160 is performed before the anode immersion step S110 and the cathode electrode immersion step S120, part or all of the solution discharged in the anode discharge step S140 or the cathode discharge step S150 is supplied to the supply step. It may be supplied to S160. Specifically, when the fuel electrode immersion step S110 is performed before the air electrode immersion step S120, the dissolved liquid discharged in the air electrode discharge step S150 may be supplied to the supply step S160. When the fuel electrode immersion step S110 is performed after the air electrode immersion step S120, the solution discharged in the fuel electrode discharge step S140 may be supplied to the supply step S160.

  In the discharging step S170, similarly to the discharging step S70, the solution is discharged from the cooling water flow path outlet or the cooling water flow path inlet. Therefore, heat generated when the transition metal is dissolved is easily taken out of the fuel cell.

  When the supply step S160 is performed before the fuel electrode immersion step S110 and the air electrode immersion step S120, the solution discharged in the discharge step S170 is supplied to the fuel electrode immersion step S110 and the air electrode immersion step S120. Specifically, when the fuel electrode immersion step S110 is performed before the air electrode immersion step S120, the solution discharged from the cooling water flow path outlet or the cooling water flow path entrance in the discharge step S170 is supplied to the fuel electrode immersion step S110. Supply. When the fuel electrode immersion step S110 is performed after the air electrode immersion step S120, the solution discharged in the discharge step S170 is supplied to the air electrode immersion step S120.

  When the supply step S160 is performed after the fuel electrode immersion step S110 and the air electrode immersion step S120, a part or all of the dissolved liquid discharged in the discharge step S170 is used for the fuel electrode immersion step S110 and the air electrode immersion step S120. May be supplied. Specifically, when the fuel electrode immersion step S110 is performed before the air electrode immersion step S120, the solution discharged in the discharge step S170 may be supplied to the fuel electrode immersion step S110. When the fuel electrode immersion step S110 is performed after the air electrode immersion step S120, the solution discharged in the discharge step S170 may be supplied to the air electrode immersion step S120.

  Next, a transition metal recovery device 31 according to a second embodiment will be described.

  As shown in FIG. 4, the recovery device 31 includes a solution supply unit 33 that supplies a solution to the inside of the fuel cell 2 and discharges the supplied solution to the outside of the fuel cell 2, a fuel electrode and an air electrode. And a voltage application unit 4 for applying a voltage to the power supply. The recovery device 31 is a device capable of performing the above-described transition metal recovery method of the second embodiment.

  As shown in FIG. 5, the solution supply unit 33 supplies the solution to the fuel electrode channel inlet 5a, supplies the solution discharged from the fuel electrode channel outlet 5b to the air electrode channel inlet 6a, The solution is discharged from the pole flow path outlet 6b.

  As shown in FIG. 5, one end of the flow path 41 provided inside the fuel cell 2 and the flow path 15b are connected by a flow path 51 provided outside the fuel cell 2. The other end of the flow channel 41 and the flow channel 16a are connected by a flow channel 52 provided outside the fuel cell 2. The flow path 51 and the flow path 52 are provided for recovering the transition metal, and the flow path 41 is already provided inside the fuel cell 2. Then, the recovery device 31 supplies and discharges the same dissolved liquid to the fuel electrode flow path 5 and the air electrode flow path 6 connected in series. Note that, inside the fuel cell 2, the flow path 41 is defined as the flow path 15a, the fuel electrode flow path 5, the flow path of the flow path 15b, and the flow path 16a, the air electrode flow path 6, and the flow path of the flow path 16b. Independent, not in communication.

  Here, for the fuel electrode flow path 5 and the air electrode flow path 6 that are connected in series, a solution supply unit that supplies a solution to the fuel electrode flow path inlet 5a and discharges the solution from the air electrode flow path outlet 6b. 33 will be described, but the order of supply and discharge of the solution to these inlets and outlets is not particularly limited. In this case, the connection configuration of the flow path 51 and the flow path 52 to the flow path 41 is appropriately changed.

  For example, when the solution supply unit 33 supplies the solution to the fuel electrode channel inlet 5a, the solution discharged from the fuel electrode channel outlet 5b is supplied to the air electrode channel inlet 6a or the air electrode channel outlet 6b. I do. When the solution supply unit 33 supplies the solution to the fuel electrode channel outlet 5b, the solution discharged from the fuel electrode channel inlet 5a is supplied to the air electrode channel inlet 6a or the air electrode channel outlet 6b. I do.

  When the solution supply unit 33 supplies the solution to the air electrode channel inlet 6a, the solution discharged from the air electrode channel outlet 6b is supplied to the fuel electrode channel inlet 5a or the fuel electrode channel outlet 5b. I do. When the solution supply unit 33 supplies the solution to the air electrode channel outlet 6b, the solution discharged from the air electrode channel inlet 6a is supplied to the fuel electrode channel inlet 5a or the fuel electrode channel outlet 5b. I do.

  When a voltage is applied to the fuel electrode and the air electrode from the voltage applying unit 4, the transition metal in the fuel electrode and the air electrode dissolves in the solution. Then, the solution containing the transition metal carried on the fuel electrode is discharged from the fuel electrode channel outlet 5b by the solution supply unit 33, and then discharged outside the fuel cell 2 through the air electrode channel 6. The discharged solution containing the transition metal carried on the air electrode is discharged to the outside of the fuel cell 2 from the air electrode channel outlet 6b. Thus, the transition metal contained in the fuel cell 2 is recovered from inside the fuel cell 2.

  When recovering the transition metal from the fuel cell 2, the solution supply unit 33 supplies the solution inside the fuel cell 2 and discharges the solution outside the fuel cell 2 without disassembling the fuel cell 2. Then, the voltage applying unit 4 applies a voltage to the fuel electrode and the air electrode from outside the fuel cell 2. Further, the solution supply unit 33 may circulate the solution in the recovery device 31 until the recovery of the transition metal from the fuel electrode and the air electrode is completed.

  Further, the recovery device 31 may include a tank unit 39 connected to the air electrode channel outlet 6b and the solution supply unit 33, and an exhaust unit 10 connected to the tank unit 39.

  The solution containing the transition metal discharged from the air electrode channel outlet 6b is supplied to the tank unit 39. The tank unit 39 stores a liquid phase composed of a solution containing a transition metal and a gas phase composed of a gas contained in the solution. The gas phase portion in the tank unit 39 is supplied to the exhaust unit 10, and the exhaust unit 10 exhausts the gas supplied from the tank unit 39 to the outside of the recovery device 31. The solution, which is a liquid phase portion in the tank section 39, is supplied to the fuel electrode channel inlet 5a by the solution supply section 33.

  As shown in FIG. 5, in the recovery device 31, the solution supply unit 33 cools the solution when supplying and discharging the solution to the fuel electrode channel 5 and the air electrode channel 6 that are connected in series. The solution may be supplied to the water channel inlet 11a, and the solution may be discharged from the cooling water channel outlet 11b. At this time, the dissolving liquid supply unit 33 supplies the dissolving liquid to the cooling water flow path 11 without disassembling the fuel cell 2 and dissolves Drain the liquid.

  As shown in FIG. 5, one end of the flow channel 42 provided inside the fuel cell 2 and the flow channel 17b are connected by a flow channel 53 provided outside the fuel cell 2. The other end of the flow path 42 and the flow path 15 a are connected by a flow path 54 provided outside the fuel cell 2. The flow path 53 and the flow path 54 are provided for recovering the transition metal, and the flow path 42 is already provided inside the fuel cell 2. Then, the recovery device 31 supplies and discharges the same dissolved liquid to the cooling water channel 11, the fuel electrode channel 5, and the air electrode channel 6 which are connected in series. Inside the fuel cell 2, the flow path 42 includes the flow path 15a, the fuel electrode flow path 5, the flow path of the flow path 15b, the flow path 16a, the air electrode flow path 6, the flow path of the flow path 16b, the flow path 17a, The cooling water flow path 11, the flow path of the flow path 17b, and the flow path 41 are independent from each other without communication.

  As described above, since the cooling water flow path 11, the fuel electrode flow path 5, and the air electrode flow path 6 are connected in series, all of the dissolved liquid supplied to the fuel electrode flow path 5 Supplied to In the cooling water channel 11, the portion of the fuel cell 2 that is heated when the transition metal is melted is cooled by the melt. Therefore, the temperature distribution in the fuel cell 2 becomes small, and the variation in the dissolution of the transition metal in the solution is suppressed.

  Here, for the cooling water flow path 11, the fuel electrode flow path 5, and the air electrode flow path 6 which are connected in series, the solution is supplied to the cooling water flow path inlet 11a and discharged from the air electrode flow path outlet 6b. The solution supply section 33 will be described, but the order of supply and discharge of the solution to these inlets and outlets is not particularly limited. In this case, the connection configuration of the flow paths 51, 52, 53, 54 is appropriately changed.

  For example, when the solution supply unit 33 supplies the solution to the cooling water channel inlet 11a, the solution discharged from the cooling water channel outlet 11b is supplied to the fuel electrode channel inlet 5a, the fuel electrode channel outlet 5b, and the air electrode flow. It is supplied to either the road entrance 6a or the air electrode channel exit 6b. When the solution supply unit 33 supplies the solution to the cooling water channel outlet 11b, the solution discharged from the cooling water channel inlet 11a is supplied to the fuel electrode channel inlet 5a, the fuel electrode channel outlet 5b, and the air electrode flow. It is supplied to either the road entrance 6a or the air electrode channel exit 6b.

  When the solution supply unit 33 supplies the solution to the fuel electrode channel inlet 5a, the solution discharged from the fuel electrode channel outlet 5b is supplied to the cooling water channel inlet 11a, the cooling water channel outlet 11b, and the air electrode flow. It is supplied to either the road entrance 6a or the air electrode channel exit 6b. When the solution supply unit 33 supplies the solution to the fuel electrode channel outlet 5b, the solution discharged from the fuel electrode channel inlet 5a is supplied to the cooling water channel inlet 11a, the cooling water channel outlet 11b, and the air electrode flow. It is supplied to either the road entrance 6a or the air electrode channel exit 6b.

  When the solution supply unit 33 supplies the solution to the air electrode channel inlet 6a, the solution discharged from the air electrode channel outlet 6b is supplied to the cooling water channel inlet 11a, the cooling water channel outlet 11b, and the fuel electrode flow. It is supplied to either the road entrance 5a or the fuel electrode channel exit 5b. When the solution supply unit 33 supplies the solution to the air electrode channel outlet 6b, the solution discharged from the air electrode channel inlet 6a is supplied to the cooling water channel inlet 11a, the cooling water channel outlet 11b, and the fuel electrode flow. It is supplied to either the road entrance 5a or the fuel electrode channel exit 5b.

  After recovering the transition metal from the fuel electrode and the air electrode, the voltage application unit 4 and the solution supply unit 33 are stopped, and the application of the voltage to the fuel electrode and the air electrode and the circulation of the solution are stopped. The transition metal in the solution is discharged from the tank unit 39 to the outside of the recovery device 31 through a drain port (not shown) provided in the tank unit 39, for example.

  As described above, according to the transition metal recovery method and the transition metal recovery device of the second embodiment, the fuel electrode flow path, the air electrode flow path, and the cooling water flow path connected in series are The same lysis solution can be supplied and drained. Therefore, it is possible to reduce the number of solution supply units that supply and discharge the fuel electrode channel and the air electrode channel and the number of tank units that store the solution discharged from the fuel electrode channel and the air electrode channel. it can.

  Further, since the fuel electrode flow path, the air electrode flow path, and the cooling water flow path are connected in series, all of the solution supplied to the fuel electrode flow path and the air electrode flow path are supplied to the cooling water flow path. Therefore, the temperature distribution in the fuel cell at the time of dissolution of the transition metal is further reduced, and the variation in the dissolution of the transition metal due to the temperature distribution in the fuel cell is further suppressed.

  According to the embodiment described above, it is possible to provide a transition metal recovery method and a transition metal recovery device that can easily recover a transition metal from a fuel cell without dismantling the fuel cell.

  Although several embodiments of the present invention have been described, these embodiments are provided by way of example and are not intended to limit the scope of the invention. These new embodiments can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and their equivalents.

  1, 31: transition metal recovery device, 2, 20: fuel cell, 3, 33: solution supply unit, 3a: first supply unit, 3b: second supply unit, 4: voltage application unit, 5: fuel electrode Flow path, 5a ... fuel electrode flow path inlet, 5b ... fuel electrode flow path outlet, 6 ... air electrode flow path, 6a ... air electrode flow path inlet, 6b ... air electrode flow path outlet, 7 ... fuel electrode output terminal, 8 ... Air electrode output terminal, 9a ... First tank part, 9b ... Second tank part, 10 ... Exhaust part, 11 ... Cooling water channel, 11a ... Cooling water channel inlet, 11b ... Cooling water channel outlet, 15a, 15b, 16a , 16b, 17a, 17b, 41, 42, 51, 52, 53, 54 ... flow path, 39 ... tank part, 50 ... fuel electrode, 60 ... air electrode, 70 ... electrolyte membrane, 80 ... membrane electrode assembly.

Claims (14)

Supplying a solution to a fuel electrode channel inlet for supplying fuel gas to the fuel cell or a fuel electrode channel outlet for discharging fuel gas from the fuel cell, and immersing the fuel electrode in the solution;
Supplying a solution to an air electrode channel inlet for supplying air to the fuel cell or an air electrode channel outlet for discharging air from the fuel cell, and immersing the air electrode in the solution;
Via a fuel electrode output terminal electrically connected to the fuel electrode and an air electrode output terminal electrically connected to the air electrode, a voltage is applied to the fuel electrode and the air electrode immersed in the solution. And dissolving the transition metal contained in the fuel electrode and the air electrode in the dissolving solution,
Discharging the solution containing the transition metal from the anode flow channel outlet or the anode flow channel inlet,
The air electrode channel outlet or the air flow channel entrance, possess a step of discharging the solution containing the transition metal,
Supplying a dissolved liquid to a cooling water flow path inlet for supplying cooling water to the fuel cell or a cooling water flow path outlet for discharging cooling water from the fuel cell;
Discharging the solution from the cooling water channel outlet or the cooling water channel inlet;
The method for recovering a transition metal further comprising:   The solution contains a halide ion, the concentration of the halide ion in the solution is 0.01 mol / L or more and 16.0 mol / L or less, and the pH of the solution is 5 or less. The method for recovering a transition metal according to claim 1.   In the step of dissolving the transition metal, the voltage applied to the fuel electrode and the air electrode includes one of the fuel electrode, one of the air electrodes, and an electrolyte membrane interposed between the fuel electrode and the air electrode. The transition metal recovery method according to claim 1 or 2, wherein the voltage is 0.10 V or more and 3.00 V or less per one of the membrane electrode assemblies. In the step of immersing the fuel electrode, the solution is supplied to the said fuel flow channel entrance, in the step of discharging the solution, according to claim 1 to 3 for discharging the solution from the fuel electrode flow path outlet The method for recovering a transition metal according to any one of the above. In the step of immersing the fuel electrode, the solution supplying to the fuel electrode flow path outlet, in the step of discharging the solution, according to claim 1 to 3 for discharging the solution from the anode flow channel entrance The method for recovering a transition metal according to any one of the above. In the step of immersing the cathode, the solution is supplied to the air electrode channel inlet, in the step of discharging the solution, according to claim 1 to 5 for discharging the solution from the cathode flow path outlet The method for recovering a transition metal according to any one of the above. In the step of immersing the cathode, the solution is supplied to the air electrode channel outlet, in the step of discharging the solution, according to claim 1 to 5 for discharging the solution from the cathode channel inlet The method for recovering a transition metal according to any one of the above. In the step of immersing the fuel electrode, the solution discharged from the fuel electrode channel outlet is supplied to the fuel electrode channel inlet, or the solution is discharged from the fuel electrode channel inlet to the fuel electrode channel outlet. The method for recovering a transition metal according to any one of claims 1 to 7 , wherein the prepared solution is supplied. In the step of immersing the air electrode, the solution discharged from the air electrode channel outlet is supplied to the air electrode channel inlet, or discharged from the air electrode channel inlet to the air electrode channel outlet. The method for recovering a transition metal according to any one of claims 1 to 8 , wherein the prepared solution is supplied. 4. The method according to claim 1, wherein in the step of immersing the fuel electrode, the solution discharged from the air electrode channel inlet or the air electrode channel outlet is supplied to the fuel electrode channel inlet or the fuel electrode channel outlet. 8. The method for recovering a transition metal according to any one of items 7 to 7 . 11. The method according to claim 10 , wherein, in the step of immersing the air electrode, the solution discharged from the fuel electrode channel inlet or the fuel electrode channel outlet is supplied to the air electrode channel inlet or the air electrode channel outlet. The method for recovering the transition metal described in the above. A solution is supplied to a fuel electrode flow path inlet for supplying fuel gas to the fuel cell or a fuel electrode flow path outlet for discharging fuel gas from the fuel cell, and the solution is supplied from the fuel electrode flow path outlet or the fuel electrode flow path inlet to the fuel cell. Dissolving liquid is supplied to the air electrode flow path inlet or the air electrode flow path outlet for discharging air from the fuel cell by discharging the solution and supplying air to the fuel cell, and the air electrode flow path outlet or the air electrode flow A solution supply unit for discharging the solution from a passage entrance;
A voltage is applied to the fuel electrode and the air electrode immersed in the solution via a fuel electrode output terminal electrically connected to the fuel electrode and an air electrode output terminal electrically connected to the air electrode. It has a voltage applying unit which,
The solution supply unit supplies a solution to a cooling water flow path inlet for supplying cooling water to a fuel cell or a cooling water flow path outlet for discharging cooling water from the fuel cell, and the cooling water flow path outlet or the cooling water flow path A transition metal recovery device for discharging the solution from an inlet . A dissolving solution supply unit configured to supply the dissolving solution to the fuel electrode flow channel inlet or the fuel electrode flow channel outlet; and a dissolving solution supplied to the air electrode flow channel inlet or the air electrode flow channel outlet. The transition metal recovery device according to claim 12 , further comprising a second supply unit that supplies the transition metal. The solution supply unit supplies the solution discharged from the air electrode channel inlet or the air electrode channel outlet to the fuel electrode channel inlet or the fuel electrode channel outlet, or the air electrode channel 13. The transition metal recovery device according to claim 12 , wherein the dissolved liquid discharged from the fuel electrode channel inlet or the fuel electrode channel outlet is supplied to an inlet or the air electrode channel outlet.

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