Recovery treatment method, and recovery treatment system

Abstract

To provide a recovery treatment method of efficiently recovering a plurality of species of components to be recovered having different solubility.SOLUTION: The recovery treatment method according to an embodiment of the present invention includes a first treatment step in which a first recovery object component is dissolved in a treatment solution from a recovery treatment object by applying a reduction treatment and an oxidation treatment to the recovery treatment object, and the peeling treatment of peeling a second recovery object component in a solid state from the recovery treatment object into the treatment solution by applying an external force to the recovery treatment object, and a second treatment step in which the treatment solution in which the first recovery object component is dissolved and the second recovery object component peeled off in the first treatment step, is subjected to a solid-liquid separation treatment to separate the treatment solution into a liquid component including the first recovery object component and a solid component including the second recovery object component.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a recovery and treatment method and a recovery and treatment system. [Background technology]

[0002] Electrochemical devices have electrochemical cells configured such that a hydrogen electrode and an oxygen electrode sandwich an electrolyte membrane. In electrochemical devices, the electrochemical cell is, for example, a membrane electrode assembly (MEA) including an electrolyte membrane formed of a solid polymer membrane, and functions as a fuel cell and an electrolysis device. For this reason, electrochemical devices are attracting attention in line with the transition to a carbon-neutral society.

[0003] In electrochemical cells, expensive and rare metals are used as electrode catalysts for the hydrogen and oxygen electrodes. Specifically, when an electrochemical cell functions as a polymer electrolyte fuel cell (PEFC), metal components such as platinum and ruthenium are used as electrode catalysts. Also, when an electrochemical cell functions as a polymer electrolyte membrane (PEM) water electrolysis device, metal components such as iridium and platinum are used as electrode catalysts.

[0004] Various techniques have been proposed for recovering target components such as the above-mentioned metal components from electrochemical cells. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 61-138541 [Patent Document 2] Patent No. 6652518 [Patent Document 3] Patent No. 6652454 [Patent Document 4] Patent No. 6109769 Summary of the Invention [Problem to be solved by the invention]

[0006] There is a demand for efficient recovery of target components such as metals from electrochemical cells. Similarly, there is a demand for efficient recovery from devices other than electrochemical cells. However, it is not easy to efficiently recover multiple target components with different solubilities.

[0007] Therefore, an object of the present invention is to provide a recovery method and recovery system that can efficiently recover a plurality of target components with different solubilities. [Means for solving the problem]

[0008] The recovery treatment method of the embodiment has a first treatment step and a second treatment step, and recovers a first component to be recovered and a second component to be recovered from a recovery treatment target containing at least the first component to be recovered and the second component to be recovered. In the first treatment step, a reduction treatment and an oxidation treatment are performed on the recovery treatment target to dissolve the first component to be recovered from the recovery treatment target in a treatment solution, and a stripping treatment is performed to apply an external force to the recovery treatment target to strip the second component to be recovered in a solid state from the recovery treatment target into the treatment solution. In the second treatment step, a solid-liquid separation treatment is performed on the treatment solution from which the first component to be recovered has been dissolved and the second component to be recovered has been stripped in the first treatment step, thereby separating the solution into a liquid component containing the first component to be recovered and a solid component containing the second component to be recovered. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a recovery treatment method and a recovery treatment system that can efficiently recover a plurality of recovery target components with different solubilities. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a flow chart showing a recovery processing method according to an embodiment. [Figure 2A] FIG. 2A is a functional block diagram that schematically shows the recovery and processing system 1 according to the embodiment. [Figure 2B] FIG. 2B is a diagram showing a state in which electrolysis is performed in the recovery treatment method of the embodiment. [Figure 3A] FIG. 3A is a functional block diagram that schematically shows a recovery and processing system 1 according to the first modification. [Figure 3B] FIG. 3B is a functional block diagram that schematically shows the recovery and processing system 1 according to the second modification. [Figure 3C] FIG. 3C is a functional block diagram that schematically shows the recovery and processing system 1 according to the third modification. DETAILED DESCRIPTION OF THE INVENTION

[0011] [A] Collection and disposal method FIG. 1 is a flow chart showing a recovery processing method according to an embodiment.

[0012] In the recovery treatment method of this embodiment, as shown in Fig. 1, a first recovery target component SK1 and a second recovery target component SK2 are recovered from a recovery treatment target SB by sequentially performing a first treatment step ST10 and a second treatment step ST20. Details will be described later, but in the first treatment step ST10, a reduction treatment, an oxidation treatment, and a stripping treatment are performed, and in the second treatment step ST20, a solid-liquid separation treatment is performed.

[0013] In this embodiment, the recovery treatment target SB is, for example, an electrochemical cell (MEA) of an electrochemical device that functions as at least one of a fuel cell device and an electrolysis device, and includes a first recovery target component SK1 and a second recovery target component SK2.

[0014] The first recovery target component SK1 is, for example, a "platinum" component used as an electrode catalyst in the hydrogen and oxygen electrodes of an electrochemical cell that constitutes an electrochemical device. The second recovery target component SK2 is, for example, a "carbon" component that constitutes the diffusion layer in the hydrogen and oxygen electrodes of the electrochemical cell.

[0015] [B] Configuration of Collection and Processing System 1 An example of a recovery and treatment system 1 used when carrying out the above recovery and treatment method will now be described.

[0016] FIG. 2A is a functional block diagram that schematically shows the recovery and processing system 1 according to the embodiment.

[0017] 2A, the recovery and processing system 1 of this embodiment has a first processing unit 10 and a second processing unit 20. Each unit constituting the recovery and processing system 1 will be explained in turn.

[0018] [B-1] Configuration of the first processing unit 10 In the recovery and processing system 1, the first processing unit 10 is provided to carry out a first processing step ST10 (see FIG. 1).

[0019] As shown in FIG. 2A, the first processing unit 10 includes a processing vessel 15, an electrolytic processing unit 150, and a stripping processing unit 16.

[0020] [B-1-1] Processing vessel 15 In first processing section 10, processing solution S15 is introduced into processing container 15. Processing solution S15 is, for example, an acidic aqueous solution (such as a hydrochloric acid aqueous solution).

[0021] [B-1-2] Electrolytic processing unit 150 In the first processing unit 10, the electrolytic processing unit 150 includes, for example, an AC power supply, and is configured to perform electrolytic processing on the SB to be recovered using the AC power supply. The SB to be recovered is electrically connected to one terminal of the AC power supply, and a counter electrode 152 is connected to the other terminal.

[0022] Specifically, in the first processing unit 10, the SB to be recovered is immersed in the processing solution S15. When performing electrolysis on the SB to be recovered, the electrolysis processing unit 150 applies a voltage between the SB to be recovered and the counter electrode 152 while the SB to be recovered is immersed in the processing solution S15. Here, a reduction process in which a reduction potential is applied to the SB to be recovered and an oxidation process in which an oxidation potential is applied to the SB to be recovered are alternately and repeatedly performed as the electrolysis process. The electrolysis process is performed, for example, by applying a voltage to the hydrogen electrode and the oxygen electrode constituting the electrochemical cell (MEA) that is the SB to be recovered. The electrolysis process may be performed by disassembling the electrochemical device and removing the electrochemical cell (MEA) from the electrochemical device, or may be performed with the electrochemical cell (MEA) attached to the electrochemical device without disassembling the electrochemical device. The counter electrode 152 may also be another electrochemical cell (MEA).

[0023] By performing the electrolysis treatment, the first recovery target component SK1 is dissolved from the recovery target SB into the treatment solution S15 in the first processing unit 10. In this embodiment, for example, the "platinum" component, which is the first recovery target component SK1, is dissolved from the recovery target SB, and the "carbon" component, which is the second recovery target component SK2, remains in the recovery target SB.

[0024] FIG. 2B is a diagram showing a state in which electrolysis is performed in the recovery treatment method of the embodiment.

[0025] As shown in Figure 2B, by performing a reduction process in which a reduction potential is applied to the recovery process target SB, platinum oxide (PtO2) formed on the surface of platinum metal (Pt) in the first recovery target component SK1 is reduced to platinum metal (Pt) (see reaction formula below).

[0026] PtO2+4H + +4e - =Pt+2H2O

[0027] Then, by performing an oxidation treatment to apply an oxidation potential to the recovery treatment target SB, the first recovery target component SK1 is converted into a dissolved component (PtCl6 2- ) (see reaction equation below).

[0028] Pt+6Cl - =PtCl6 2- +4e -

[0029] Then, the carbon component, which is the second recovery target component SK2, remains in the recovery treatment target SB.

[0030] In this way, by alternately repeating a reduction process in which a reduction potential is applied to the recovery treatment target SB and an oxidation process in which an oxidation potential is applied to the recovery treatment target SB as an electrolysis process, the platinum component, which is the first recovery target component SK1, can be efficiently dissolved from the recovery treatment target SB into the treatment solution S15. The rate at which the platinum component, which is the first recovery target component SK1, dissolves into the treatment solution S15 (dissolution rate) increases according to the time for which the electrolysis process is performed (electrolysis time).

[0031] [B-1-3] Peeling processing unit 16 In the first processing unit 10, the peeling processing unit 16 performs a peeling process in which the second recovery target component SK2 is peeled off in a solid state from the recovery target SB into the processing solution S15 by applying an external force to the recovery target SB.

[0032] In the first processing unit 10, the peeling processing unit 16 includes, for example, an ultrasonic vibrator, and applies an external force to the recovery processing target SB by vibrating the processing solution S15 using the ultrasonic vibrator. As a result, in the first processing unit 10, the "carbon" component, which is the second recovery processing target component SK2, is peeled off in a solid state from the recovery processing target SB and settles in the processing solution S15.

[0033] [B-2] Configuration of second processing unit 20 In the recovery and processing system 1, the second processing unit 20 is provided to carry out a second processing step ST20 (see FIG. 1).

[0034] The second processing unit 20 includes a solid-liquid separator and is configured to perform solid-liquid separation processing on the processing solution S15 from which the first component SK1 to be recovered has dissolved and the second component SK2 to be recovered has been separated in the first processing unit 10. As a result, in the second processing unit 20, the processing solution S15 is separated into a liquid component S21 containing the first component SK1 to be recovered and a solid component S22 containing the second component SK2 to be recovered.

[0035] [C] Summary As described above, in this embodiment, in the first treatment step (ST10), reduction treatment and oxidation treatment are performed on the recovery treatment target SB, thereby dissolving the first recovery target component SK1 from the recovery treatment target SB into the treatment solution S15. At the same time, in the first treatment step (ST10), a stripping treatment is performed in which an external force is applied to the recovery treatment target SB, thereby stripping the second recovery target component SK2 in a solid state from the recovery treatment target SB into the treatment solution S15. Then, in the second treatment step (ST20), a solid-liquid separation treatment is performed on the treatment solution S15 from which the first recovery target component SK1 has been dissolved and the second recovery target component SK2 has been stripped in the first treatment step (ST10). This separates the treatment solution S15 into a liquid component S21 containing the first recovery target component SK1 and a solid component S22 containing the second recovery target component SK2.

[0036] Therefore, in this embodiment, it is possible to efficiently separate and recover the first target component SK1 and the second target component SK2, which has a different solubility from the first target component SK1. When the solid component recovered as the second target component SK2 was analyzed by EDS analysis, the carbon component in the solid component was found to be 88.3 at%.

[0037] [D] Variation In the above embodiment, the case was described in which the external force used in the first processing step (ST10) to perform the peeling process to peel the second recovery target component SK2 from the recovery processing target SB is a force generated by vibrating the processing solution S15, but this is not limited to this.

[0038] FIG. 3A is a functional block diagram that schematically shows a recovery and processing system 1 according to the first modification.

[0039] 3A, in this modification, the configuration of stripping processing unit 16b in first processing unit 10 for performing first processing step ST10 (see FIG. 1) is different from that in the above embodiment (see FIG. 2A). Unlike the above embodiment, in this modification, stripping processing unit 16b includes, for example, a stirrer that stirs processing solution S15 to generate a flow in processing solution S15.

[0040] When performing the peeling process in this modified example, a force generated by the flow of the processing solution S15 is applied as an external force to the recovery processing target SB. As a result, in this modified example as well, the second recovery target component SK2 can be peeled in a solid state from the recovery processing target SB into the processing solution S15, as in the above embodiment.

[0041] FIG. 3B is a functional block diagram that schematically shows the recovery and processing system 1 according to the second modification.

[0042] 3B, in this modification, the configuration of the stripping processing unit 16c in the first processing unit 10 for performing the first processing step ST10 (see FIG. 1) is different from that in the above embodiment (see FIG. 2A). In this modification, unlike the above embodiment, the stripping processing unit 16c includes, for example, a pump, and is configured to suck up the processing solution S15 from the processing container 15 and then return the sucked up processing solution S15 to the processing container 15, thereby generating a flow in the processing solution S15.

[0043] When performing the peeling process in this modified example, the force generated by the flow of the processing solution S15 is also applied as an external force to the recovery processing target SB. As a result, in this modified example as well, the second recovery target component SK2 can be peeled in a solid state from the recovery processing target SB into the processing solution S15, as in the above embodiment.

[0044] In addition to the above-described modified examples, various external forces can be used to perform the delamination process. For example, a vibrator that vibrates the recovery process target SB may be installed as the delamination processing unit, and the force generated by vibrating the recovery process target SB may be used as the external force when performing the delamination process.

[0045] Furthermore, the external force for performing the peeling process may be a force generated by a flow of electrolytic gas generated from the recovery treatment target SB in at least one of an electrolytic process in which a reduction potential is applied to the recovery treatment target SB and an electrolytic process in which an oxidation potential is applied to the recovery treatment target SB. In this case, the conditions of the electrolytic process are appropriately adjusted so that the electrolytic gas is generated from the recovery treatment target SB by the electrolytic process.

[0046] Furthermore, the external force for performing the peeling process is gravity, and the first processing unit 10 does not necessarily have to include the peeling processing unit 16 or the like.

[0047] In the above embodiment, the case where electrolytic treatment is performed on the recovery treatment target SB in the first treatment step (ST10) to dissolve the first recovery target component SK1 from the recovery treatment target SB into the treatment solution S15 is described, but this is not limited to this.

[0048] FIG. 3C is a functional block diagram that schematically shows the recovery and processing system 1 according to the third modification.

[0049] As shown in FIG. 3C, in this modification, a part of the configuration of first processing apparatus 10 for performing first processing step ST10 (see FIG. 1) differs from that of the above embodiment (see FIG. 2A).

[0050] In this modification, the first processing unit 10 includes a processing vessel 170 , a reducing agent supply unit 181 , an oxidizing agent supply unit 191 , and a dissolution processing unit 192 .

[0051] The processing container 170 is configured to accommodate the recovery processing target SB therein.

[0052] The reducing agent supply unit 181 is, for example, a tank, and is provided to perform a reduction treatment on the recovery treatment target SB. When performing the reduction treatment, a treatment medium S181 containing a reducing agent flows and is supplied from the reducing agent supply unit 181 to the recovery treatment target SB accommodated in the treatment container 170. As a result, a reducing agent contact treatment is performed inside the treatment container 170 in which the reducing agent comes into contact with the recovery treatment target SB, and a reduction treatment is performed to reduce the recovery treatment target SB. Here, by performing the reduction treatment, for example, an oxide of the first recovery target component SK1 is reduced to the first recovery target component SK1 in the recovery treatment target SB (see FIG. 2B). For example, hydrogen gas, carbon monoxide gas, etc. can be used as the reducing agent.

[0053] The oxidizing agent supply unit 191 is, for example, a tank, and is provided to perform an oxidation treatment on the recovery treatment target SB. When performing the oxidation treatment, a treatment medium S191 containing an oxidizing agent flows and is supplied from the oxidizing agent supply unit 191 to the recovery treatment target SB accommodated in the treatment container 170. As a result, an oxidizing agent contact treatment is performed inside the treatment container 170 in which the oxidizing agent comes into contact with the recovery treatment target SB, and an oxidation treatment is performed in which the recovery treatment target SB is oxidized. As a result, as described above, in the recovery treatment target SB, the first recovery target component SK1 is oxidized to a dissolved component that dissolves in a solvent such as water (see FIG. 2B). As the oxidizing agent, ozone, chlorine gas, or the like can be used.

[0054] The dissolution processing unit 192 is, for example, a tank into which a solvent such as water is introduced. The dissolution processing unit 192 also receives the recovery processing target SB that has been subjected to reduction processing in the reducing agent supply unit 181 and oxidation processing in the oxidizing agent supply unit 191. As a result, in the dissolution processing unit 192, for example, the first recovery target component SK1 after oxidation processing is dissolved in a solvent such as water, and a processing solution S192 is obtained. Although not shown in the figure, the dissolution processing unit 192 also performs a peeling process by an external force due to the flow of the processing solution S192, and the second recovery target component SK2 is peeled off in a solid state from the recovery processing target SB into the processing solution S15.

[0055] Therefore, in this modified example, the same effects as in the above embodiment can be obtained.

[0056] In the above-described embodiments, the first component SK1 to be recovered is a platinum component and the second component SK2 to be recovered is a carbon component, but this is not limiting. The first component SK1 to be recovered and the second component SK2 to be recovered may be other components, such as a case where the first component SK1 to be recovered is a ruthenium component and the second component SK2 to be recovered is an indium oxide component.

[0057] <Other> Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0058] 1: recovery treatment system, 10: first treatment section, 15: treatment vessel, 16: stripping treatment section, 16b: stripping treatment section, 16c: stripping treatment section, 20: second treatment section, 150: electrolytic treatment section, 152: counter electrode, 170: treatment vessel, 181: reducing agent supply section, 191: oxidizing agent supply section, 192: dissolution treatment section, SB: recovery treatment target, S15: treatment solution, S181: treatment medium, S191: treatment medium, S192: treatment solution, S21: liquid component, S22: solid component, SK1: first recovery target component, SK2: second recovery target component, ST10: first treatment step, ST20: second treatment step

Claims

1. A recovery treatment method for recovering each of a first recovery target component and a second recovery target component from a recovery treatment target including at least the first recovery target component and a second recovery target component, the method comprising: a first treatment step of performing a reduction treatment and an oxidation treatment on the recovery treatment object to dissolve the first recovery target component from the recovery treatment object in a treatment solution, and performing a stripping treatment to strip the second recovery target component in a solid state from the recovery treatment object into the treatment solution by applying an external force to the recovery treatment object; a second treatment step in which the treatment solution from which the first component to be recovered has been dissolved and the second component to be recovered has been separated in the first treatment step is subjected to a solid-liquid separation treatment to separate the treatment solution into a liquid component containing the first component to be recovered and a solid component containing the second component to be recovered; having Recovery processing method.

2. In the first processing step, With the recovery treatment object immersed in the treatment solution, The reduction treatment is an electrolysis treatment in which a reduction potential is applied to the recovery treatment target so as to reduce an oxide of the first recovery target component to the first recovery target component, and The oxidation treatment is performed by applying an oxidation potential to the target to be recovered so that the first target component to be recovered is oxidized and dissolved in the treatment solution. The recovery and treatment method according to claim 1.

3. In the first processing step, The reduction treatment is a reducing agent contact treatment in which a reducing agent for reducing oxides of the first target component to the first target component is brought into contact with the target component for recovery treatment, and an oxidizing agent contact treatment is carried out as the oxidation treatment, in which the treatment solution containing an oxidizing agent for oxidizing the first component to be recovered is brought into contact with the target to be recovered, thereby dissolving the first component to be recovered in the treatment solution; The recovery and treatment method according to claim 1.

4. In the first processing step, the external force is a force generated by the flow of the processing solution. The recovery and treatment method according to claim 1.

5. In the first processing step, the external force is a force generated by vibrating the processing solution. The recovery and treatment method according to claim 1.

6. In the first processing step, the external force is a force generated by vibrating the object to be recovered. The recovery and treatment method according to claim 1.

7. In the first treatment step, the external force is a force generated by a flow of electrolytic gas generated from the recovery treatment target in at least one of an electrolysis treatment in which a reduction potential is applied to the recovery treatment target and an electrolysis treatment in which an oxidation potential is applied to the recovery treatment target. The recovery and treatment method according to claim 1.

8. The recovery treatment target is an electrochemical device that functions as at least one of a fuel cell device and an electrolysis device. The recovery and treatment method according to claim 1.

9. A recovery treatment system that recovers each of a first recovery target component and a second recovery target component from a recovery treatment target that includes at least the first recovery target component and a second recovery target component, a first processing unit configured to perform a reduction treatment and an oxidation treatment on the recovery treatment object to dissolve the first recovery target component from the recovery treatment object in a treatment solution, and to perform a stripping treatment to strip the second recovery target component from the recovery treatment object in a solid state into the treatment solution by applying an external force to the recovery treatment object; a second processing unit configured to separate the treatment solution into a liquid component containing the first target component to be recovered and a solid component containing the second target component to be recovered by performing a solid-liquid separation process on the treatment solution from which the first target component to be recovered has been dissolved and the second target component to be recovered has been separated in the first processing unit; having Collection and processing system.

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