CN-122012925-A - Valuable material recovery method

CN122012925ACN 122012925 ACN122012925 ACN 122012925ACN-122012925-A

Abstract

The embodiment provides a valuable object recovery method for efficiently recovering valuable objects. The method for recovering valuable materials according to an embodiment is a method for recovering valuable materials from an electrochemical device having a catalyst containing an oxide of a noble metal, and includes a step of reducing the oxide while heating an object having the catalyst, and a step of dissolving the noble metal after reduction as ions in a solution by applying a voltage to the object in contact with the solution containing at least one selected from the group consisting of an ionic species and a chemical species capable of forming a complex with the noble metal, increasing the absolute value of the voltage over time, and then holding the voltage, thereby periodically reversing the polarity of the voltage, and performing an electrolytic reaction.

Inventors

Jin Cunxiang is flat
YAGYU MOTOSHIGE
Da Senxiao

Assignees

株式会社东芝
东芝能源系统株式会社

Dates

Publication Date: 20260512
Application Date: 20250718
Priority Date: 20241112

Claims (7)

1. A valuable material recovery method, which is a method for recovering valuable materials from an electrochemical device, Wherein the electrochemical device has a catalyst comprising an oxide of a noble metal, The method comprises the following steps: A step of reducing the oxide while heating the object having the catalyst, and Applying a voltage to the object in contact with a solution containing at least one selected from the group consisting of an ionic species and a chemical species capable of forming a complex with the noble metal, and holding the voltage after increasing an absolute value of the voltage over time, thereby periodically reversing a polarity of the voltage to perform an electrolytic reaction, thereby dissolving the noble metal after reduction as an ion in the solution.
2. The method for recovering valuable substances according to claim 1, wherein the step of reducing the oxide is performed by: A first method of supplying a solution containing a reducing agent to bring the reducing agent into contact with the object; A second method of supplying a reducing gas to bring the reducing gas into contact with the object, or And a third method of bringing the electrolyte into contact with the object, applying a voltage to the object, and performing an electrolytic reaction without reversing the polarity of the voltage.
3. The method for recovering valuable substances according to claim 1, wherein the object has: An electrode containing the catalyst, and A solid polymer electrolyte membrane.
4. The method for recovering valuable substances according to claim 1, wherein the step of reducing the oxide is performed at a temperature of 100 ℃ or higher.
5. The method for recovering valuable substances according to claim 1, wherein the step of dissolving the noble metal is alternately repeated for a first period and a second period, The first period is a period in which the voltage is held after the voltage value is linearly or curvedly reduced from a first value to a second value lower than the first value, The second period is a period in which the voltage is held after the voltage is linearly or curvedly increased from a third value equal to or different from the first value to a fourth value higher than the third value.
6. The method for recovering valuable substances according to claim 5, wherein, in the first period, a time required for the voltage to reach the second value from the first value is 0.6 seconds or longer, In the second period, the time required from the third value to the fourth value of the voltage is 0.6 seconds or longer.
7. The value recovery method of claim 1, wherein the catalyst comprises at least one noble metal selected from the group consisting of platinum, iridium, ruthenium, rhodium, palladium, platinum, gold, and rhenium.

Description

Valuable material recovery method Reference to related applications The present application enjoys priority of Japanese patent application No. 2024-197484 (application date: 11/12/2024). The present application includes the entire content of the basic application by referring to the basic application. Technical Field Embodiments of the present invention relate to a valuable material recovery method. Background With the development of worldwide carbon-neutral society, hydrogen is attracting attention as a substitute for fossil energy. As one of the currently considered hydrogen utilization methods, there is a fuel cell that electrochemically reacts hydrogen with oxygen to obtain electric energy. Among fuel cells, a Polymer Electrolyte Fuel Cell (PEFC) that uses a polymer electrolyte membrane and operates at a temperature of 100 ℃ or less has been sold in 2009 as a domestic fuel cell cogeneration system (trade name: d frame (registered trademark)). PEFCs are also beginning to be mounted on mobile bodies such as Fuel Cell Vehicles (FCV), forklifts, buses, and trucks, and future demands for PEFCs are expected to increase. Meanwhile, technology development has been performed to produce a large amount of hydrogen used in PEFC by electrolysis of water. Various methods for this water electrolysis have been developed, mainly including high-temperature vapor electrolysis using water vapor at several hundred degrees and solid polymer electrolyte membrane (Polymer Electrolyte Membrane: PEM) operation at around room temperature. The PEM-type water electrolysis apparatus has a feature that high-temperature operation is not required, and battery development is easy because the construction of the water electrolysis apparatus is similar to that of PEFC, and a PEM-type water electrolysis apparatus of megawatt scale is introduced worldwide. The PEM-type water electrolysis apparatus is composed of the same components as the PEFC, and performs the electrolysis reaction of water in a Membrane Electrode Assembly (MEA) composed of an electrolyte membrane, an electrode catalyst, and a Gas Diffusion Layer (GDL). For the purpose of reducing the energy during the electrolytic reaction, noble metal elements that are likely to undergo a hydrogen-generating reaction or an oxygen-generating reaction are generally used as electrode catalysts. Currently, the cathode for the hydrogen generating reaction is formed using platinum, and the anode for the oxygen generating reaction is formed using a catalyst containing iridium. In order to realize a carbon-neutral society, the introduction of PEFC and PEM-type water electrolysis apparatuses is inevitably increased, and it is necessary to secure valuable substances such as noble metal elements used in these facilities. As means for ensuring noble metal elements, development of new mine, development of mining technology, and development of recycling technology are mentioned. However, most of noble metal elements such as platinum, ruthenium, iridium are ensured overseas, and problems such as collisions and resource contention cannot be solved only by development of mine development and mining techniques. Therefore, development of a technique for recovering noble metal elements from an already marketed apparatus is important. Disclosure of Invention The invention provides a valuable object recovery method for efficiently recovering valuable objects. The method for recovering valuable materials according to an embodiment is a method for recovering valuable materials from an electrochemical device having a catalyst containing an oxide of a noble metal, and includes a step of reducing the oxide while heating an object having the catalyst, and a step of dissolving the noble metal after reduction as ions in a solution by applying a voltage to the object in contact with the solution containing at least one selected from the group consisting of an ionic species and a chemical species capable of forming a complex with the noble metal, increasing the absolute value of the voltage over time, and then holding the voltage, thereby periodically reversing the polarity of the voltage, and performing an electrolytic reaction. Drawings Fig. 1 is a flowchart for explaining an example of a valuable material recovery method. Fig. 2 is a schematic diagram showing an example of an object from which valuable substances are collected. Fig. 3 is a graph showing a time change in a voltage applied to an electrochemical device for recovering valuable substances by electrolysis in the related art. Fig. 4 is a graph showing a time change in voltage in the embodiment. Fig. 5 is a schematic diagram showing an electric circuit (equivalent circuit) inside the electrochemical device. Fig. 6 is a graph showing a time change of the voltage E. Fig. 7 is a graph showing a time change of the current i. Fig. 8 is a diagram showing an example of time variation of the voltage E. Fig. 9 is a diagram showing an example of time change of the cu