JP2009235552A - Metal recovery apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal recovery apparatus capable of easily recovering a desired metal contained in a workpiece. <P>SOLUTION: In the metal recovery apparatus 1 for recovering the metal contained in the workpiece, while a molten salt m is pooled in an electrolytic cell 10, anodic dissolution of the metal contained in the workpiece w into the molten salt is induced by applying electric current to an anodic dissolution electrode 20 and an intermediate electrode 40 so that the anodic dissolution electrode 20 and the intermediate electrode 40 function as an anode and a cathode, respectively. After the application of the electric current is completed, the dissolved metal ion is deposited onto a recovery electrode 30 as a metal or an alloy by applying electric current to the intermediate electrode 40 and the recovery electrode 30 so that the intermediate electrode 40 and the recovery electrode 30 function as an anode and a cathode, respectively. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a metal recovery apparatus and method for recovering metal contained in an object to be processed.

  Valuable metals such as aluminum, copper, zinc, titanium, indium, tin, platinum, silver, and zirconium are used for various types of waste such as electrical and electronic products, fuel cells, and catalytic devices, and spent nuclear fuel in nuclear power generation. From the viewpoint of effectively using scarce resources, it is required to recover these efficiently. As conventional metal recycling, a method using molten salt electrolysis has been conventionally known.

  For example, in Patent Document 1, chlorine gas is blown into a molten salt, a metal ion is supplied to the molten salt by direct reaction (chlorination) with the alloy, and then metal ions are reduced at the cathode by electrolysis. A metal recovery device for precipitating the metal is disclosed.

Patent Document 2 discloses a metal recovery device that electrolyzes an alloy as an anode, elutes only a specific metal component as a metal ion in a molten salt, reduces the metal ion at the cathode, and deposits a metal. Has been.
Japanese Patent Laid-Open No. 9-43389 JP 2003-344578 A

  However, the metal recovery device disclosed in Patent Document 1 generates a large amount of toxic chlorine gas at the anode together with the deposition of the metal at the cathode, and it is necessary to reuse this in the chlorination process. There was a problem in terms of workability.

  In addition, the metal recovery device disclosed in Patent Document 2 cannot optimize the anode elution conditions and the deposition conditions individually because the anode elution of the metal at the anode and the metal deposition at the cathode are performed simultaneously. Therefore, it is necessary to perform difficult work of adjusting the component ratio of the molten salt and the bath temperature so as to satisfy both conditions at the same time, and there is still a problem in terms of workability.

  Then, an object of this invention is to provide the metal collection | recovery apparatus and method which can collect | recover the desired metals contained in a to-be-processed object easily.

  The object of the present invention is a metal recovery device for recovering a metal contained in an object to be processed, an electrolytic cell capable of storing a molten salt, an anodic dissolution electrode disposed in the electrolytic cell, and a recovery electrode And the intermediate electrode, the electrode for anodic dissolution has a holding portion for holding the object to be processed, and the molten salt is stored in the electrolytic cell, and the electrode for anodic dissolution and the intermediate electrode By passing an electric current between the anodic dissolution electrode and the intermediate electrode so that the electrodes function as an anode and a cathode, respectively, the metal contained in the object to be eluted is dissolved into the molten salt. By passing a current between the intermediate electrode and the recovery electrode so that the intermediate electrode and the recovery electrode function as an anode and a cathode, respectively, the eluted metal ions are applied to the recovery electrode as a metal or an alloy. Deposit It is achieved by the metal recovery apparatus.

  Further, the object of the present invention is a metal recovery method for recovering a metal contained in an object to be processed, wherein the molten salt is stored in an electrolytic cell to hold the object to be processed, and for recovery An electrode immersing step of immersing the electrode and the intermediate electrode in the molten salt; and between the anodic dissolution electrode and the intermediate electrode so that the anodic dissolution electrode and the intermediate electrode function as an anode and a cathode, respectively. And the intermediate electrode and the recovery electrode function as an anode and a cathode, respectively, after the elution step is completed. A metal recovering method comprising: depositing eluted metal ions as metal or alloy on the cathode by energizing between the intermediate electrode and the recovery electrode It is achieved by.

  ADVANTAGE OF THE INVENTION According to this invention, the metal recovery apparatus and method which can collect | recover the desired metals contained in a to-be-processed object easily can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of a metal recovery apparatus according to an embodiment of the present invention. As shown in FIG. 1, the metal recovery apparatus 1 includes an electrolytic tank 10 that stores a molten salt m as an electrolytic bath, an anodic dissolution electrode 20 that is disposed in the electrolytic tank 10, a recovery electrode 30, and an intermediate The electrode 40 is provided. As will be described later, the metal melting electrode 20 always functions as an anode, the recovery electrode 30 always functions as a cathode, and the intermediate electrode 40 functions as a cathode or an anode.

  The anodic dissolution electrode 20 includes a holding portion 22 for holding the workpiece w. As the holding | maintenance part 22, the bowl-shaped container which consists of a perforated board and a net board can be mentioned, for example, The to-be-processed object w can be accommodated in an inside. The holding part 22 is made of a conductive material, and is preferably made of a metal having a smaller ionization tendency than a metal element to be collected, or a carbon-based material such as graphite or conductive diamond, and a metal such as nickel ferrite. Conductive ceramics made of oxide, nitride, or boride can also be used. In this way, the workpiece w itself accommodated in the holding part 22 can function as an anode. The holding unit 22 may have a configuration other than that described above as long as the workpiece w can be energized. For example, the holding unit 22 may be configured from a clamping member that clamps the workpiece w.

  The material for the collection electrode 30 is preferably selected according to the metal or alloy to be deposited, but is not particularly limited as long as it does not significantly impair the strength and durability as a cathode by reacting with the metal or alloy to be collected. Further, when there is a possibility that the deposits on the collection electrode 30 may fall off, it is preferable to install a container serving as a tray below the collection electrode 30.

  The anodic dissolution electrode 20 and the recovery electrode 30 are configured to be individually movable in the vertical direction by a drive mechanism (not shown), and the work for accommodating the workpiece w in the holding unit 22 and the recovery electrode The recovery operation of the metal or alloy deposited on 30 can be easily performed.

  The intermediate electrode 40 is composed of a gas electrode including a gas chamber 42 to which a gas is supplied and an electrode member 44 disposed below the gas chamber 42.

  The gas chamber 42 is connected to a gas supply source (not shown) via a supply valve (not shown), and is configured to be able to seal the supply gas. Excess gas can be discharged through an exhaust valve (not shown). In the present embodiment, the gas chamber 42 is filled with a mixed gas of hydrogen and hydrogen chloride.

  For the electrode member 44, a porous carbon material such as graphite can be preferably used, and a catalyst such as platinum, iridium, and ruthenium may be appropriately supported. Further, in order to improve the formation of the three-phase interface between the gas, the electrode member, and the molten salt, when the gas electrode is operated at normal pressure, the upper surface of the electrode member 44 is disposed above the bath surface of the molten salt m. It is preferable. On the other hand, when the gas electrode is operated under pressure, it is preferable to adjust the pressure balance by disposing the upper surface of the electrode member 44 below the bath surface of the molten salt m. In order to facilitate such adjustment, the intermediate electrode 40 may also be configured to be vertically movable by a drive mechanism (not shown).

  The above-described metal recovery apparatus 1 selectively selects between the anodic dissolution electrode 20 and the intermediate electrode 40 or between the intermediate electrode 40 and the recovery electrode 30 from the DC power supply 46 via the switching element 48. It is comprised so that electricity can be supplied.

Next, a method for recovering a desired metal from the workpiece w using the metal recovery apparatus 1 having the above configuration will be described. The object to be processed w is not particularly limited as long as it contains a metal material, and is a part containing valuable metal in the collected electrical / electronic product, fuel cell, catalyst device, etc., metal processing cutting waste, or Spent nuclear fuel and the like can be exemplified, and in particular, those containing binary or multi-component alloys can be preferably exemplified. Moreover, also when collect | recovering metals from the metal oxide in the to-be-processed object w, it is possible to use the metal collection | recovery apparatus 1 of this embodiment. Here, when the workpiece w contains a metal oxide, (1) only the metal portion is held at a potential at which the anode is eluted and the oxide is left as a residue. (2) the metal portion is held at a more noble potential than There is a method in which the anode is eluted and the metal oxide is chlorinated to form metal ions and oxide ions (O ²⁻ ). (3) The anode is eluted after the metal oxide is reduced by pretreatment. As a pretreatment of (3), a method in which a metal oxide is reacted with a reducing gas such as hydrogen, or a highly reducible metal (for example, Li) contained in the molten salt m is electrodeposited and the oxide ( For example, a method of forming Li ₂ O) can be mentioned. In some of the above cases, oxide ions (O ²⁻ ) are supplied into the molten salt. Therefore, when this is a problem, it is preferable to perform reduction with hydrogen or the like in advance.

  In this embodiment, the case where the to-be-processed object w is an alloy (AB) which consists of two types of different metals A and B is demonstrated as an example.

Examples of the molten salt m stored in the electrolytic cell 10 include LiF, NaF, KF, RbF, CsF, LiCl, NaCl, KCl, RbCl, CsCl, LiBr, NaBr, KBr, RbBr, CsBr, LiI, NaI, and KI. , RbI, and alkali metal halides such as _{CsI, MgF 2, CaF 2,} SrF 2, BaF 2, MgCl 2, CaCl 2, SrCl 2, BaCl 2, MgBr 2, CaBr 2, SrBr 2, BaBr 2, MgI 2 , CaI ₂ , SrI ₂ , BaI _{2 and} other alkaline earth metal halides. These compounds can be used individually or in combination of 2 or more types. The combination and mixing ratio of the compounds are not limited and can be appropriately set according to the desired operating temperature of the molten salt m.

More specifically, at least one of the following (1) to (4) can be preferably used as the molten salt m.
(1) LiCl-KCl
[Composition ratio: LiCl: KCl = 35-100 mol%: 65-0 mol% is preferable, and 55-65 mol%: 45-35 mol% is more preferable. ]
(2) LiCl-KCl-CsCl
[Composition ratio: LiCl: KCl: CsCl = 57.5: 13.3: 29.2 mol% is preferred. However, the composition ratio may be changed by about 20%. ]
(3) LiBr-KBr
[Composition ratio: LiBr: KBr = 35-100 mol%: 65-0 mol% is preferable, and 60-70 mol%: 40-30 mol% is more preferable. ]
(4) LiBr-KBr-CsBr
[Composition ratio: LiBr: KBr: CsBr = 56.1: 18.9: 25.0 mol% is preferred. However, the composition ratio may be changed by about 20%. ]
The temperature of the molten salt m varies depending on the type and composition ratio of the molten salt m to be used. For example, when the molten salt m made of LiCl—KCl is used, it is preferably set to 400 to 500 ° C. After the molten salt m is heated to a predetermined temperature by a heating means (not shown), the switching element 48 is operated to energize between the anodic dissolution electrode 20 and the intermediate electrode 40, and as shown in FIG. An elution step is performed in which the melting electrode 20 functions as an anode and the intermediate electrode 40 functions as a cathode.

  By controlling the potential of the anodic dissolution electrode 20 with reference to a reference electrode (not shown) immersed in the molten salt m, the alloy AB contained in the workpiece w held on the anodic dissolution electrode 20 is controlled. Only one metal A can be anodicly eluted in the molten salt. The control of the anode potential can also be performed by adjusting the electrolysis voltage and the electrolysis current from the relationship between the voltage and current of the DC power supply 46 measured in advance and the anode potential.

  In the intermediate electrode 40, hydrogen chloride gas contained in the supply gas receives electrons in the electrode member 44, and chloride ions are generated and supplied to the molten salt. That is, the following reaction occurs in the anodic dissolution electrode 20 and the intermediate electrode 40.

Electrode for anodic dissolution (anode) 20: AB → B + A (I) + e ⁻
Intermediate electrode (cathode) 40: HCl (g) + e ⁻ → 1/2 H ₂ (g) + Cl ⁻
By the way, in the intermediate electrode 40, if the electrode potential becomes too low, the following reaction may occur. Therefore, the electrode potential during electrolysis is monitored so that the ions of the metal A are not reduced by the intermediate electrode 40. It is preferable to keep it.

Intermediate electrode 40: A (I) + e ⁻ → A
Thus, after electrolysis is performed until most of the metal A contained in the workpiece w is eluted with the anode, the energization is terminated by the operation of the switching element 48, and the electrolysis for elution of the anode is stopped.

  After completion of the elution step, the switching element 48 is operated to energize the intermediate electrode 40 and the recovery electrode 30 and, as shown in FIG. Start the deposition step to allow the to function as a cathode.

  By controlling the potential of the recovery electrode 30, the metal ions in the molten salt are reduced by receiving electrons at the recovery electrode 30, and the metal A is deposited on the surface of the recovery electrode 30. In the intermediate electrode 40, chloride ions in the molten salt are oxidized by the electrode member 44 to release electrons, and are taken into the gas chamber 42 as hydrogen chloride gas. That is, the following reaction occurs at the intermediate electrode 40 and the recovery electrode 30.

Intermediate electrode (anode) 40: 1/2 H ₂ (g) + Cl ⁻ → HCl (g) + e ⁻
Recovery electrode (cathode) 30: A (I) + e ⁻ → A
Thus, after electrolysis is performed until most of the metal ions are deposited, the operation of the switching element 48 stops the energization. As a result, only the metal B remains in the holding portion 22 of the anodic dissolution electrode 20, and only the metal A precipitates on the collection electrode 30, so that the two types of metals A and B contained in the alloy AB are respectively separated. Can be collected individually.

  The method for recovering the metal from the object to be processed is not necessarily limited to that of the present embodiment, and a reaction generally used as a recycling technique using a molten salt can be used. For example, after eluting two or more kinds of metals contained in the object to be processed into the molten salt in the elution step, the cathode potential may be controlled in the precipitation step to deposit a desired metal. Alternatively, the elution step and the precipitation step can be repeated. The precipitate in the collection electrode 30 is not limited to a single element metal, but may be an alloy in which two or more kinds of metal ions eluted in the molten salt are reduced and precipitated, or one or more kinds eluted in the molten salt. The metal ions may be reduced and alloyed with the cathode material.

  As described above, according to the metal recovery apparatus 1 of the present embodiment, in addition to the anodic dissolution electrode 20 and the recovery electrode 30, by providing the new intermediate electrode 40, the metal from the object to be processed to the molten salt can be obtained. Anode elution and precipitation of the eluted metal ions can be performed in separate independent processes, and the anode elution conditions at the anode dissolution electrode 20 and the deposition conditions at the collection electrode 30 are individually controlled precisely. Can do. Therefore, the conventional adjustment of the composition and temperature of the molten salt serving as the electrolytic bath is unnecessary, and the metal can be easily recovered from the object to be processed.

  Further, the mixed gas of hydrogen and hydrogen chloride supplied to the intermediate electrode 40 consumes the hydrogen chloride gas at the intermediate electrode 40 during the anode elution of the metal from the workpiece w to the molten salt, and the mixing ratio changes. When the eluted metal ions are deposited, hydrogen chloride gas is generated again, and the mixing ratio returns to the original state. Therefore, since the minimum amount of hydrogen gas and hydrogen chloride gas can be sealed in a closed chamber and the metal recovery operation can be repeated by using the closed cycle, harmful chlorine gas can be released to the outside. It can be effectively prevented. The height of the bath surface of the molten salt in the electrode member 44 varies depending on the change in the internal pressure of the gas chamber 42 due to the consumption or generation of hydrogen chloride gas, so the amount of gas sealed in the gas chamber 42 is increased to change the pressure. It is preferable to make the electrode member 44 smaller or use a electrode member 44 having a large height so that the electrode member 44 is always in contact with the molten salt even if the height of the bath surface changes. Further, the intermediate electrode 40 can be moved up and down to cope with a change in the internal pressure of the gas chamber 42.

  In this embodiment, the case where the object to be processed is an alloy made of two kinds of metals A and B has been described as an example. By controlling the desired metal or alloy to remain on the anodic dissolution electrode 20 or by depositing it on the recovery electrode 30 as a metal or alloy, the metal can be recovered in the same manner as described above.

In the present embodiment, a mixed gas of hydrogen and hydrogen chloride is used as the supply gas to the intermediate electrode 40. However, anion ions are introduced during energization between the anodic dissolution electrode 20 and the intermediate electrode 40. Any gas that can be generated and supplied to the molten salt may be used, and other gases such as chlorine gas and bromine gas may be used depending on the type of the molten salt m. For example, when bromine gas (Br ₂ ) or hydrogen bromide (HBr) is used, it is preferable to use a bromide-based molten salt (such as LiBr-KBr).

  As described above, one embodiment of the present invention has been described in detail, but the intermediate electrode of the present invention is based on an oxidation-reduction reaction during energization between the anode and the intermediate electrode and during energization between the intermediate electrode and the cathode. Any structure can be used as long as the substance can be reversibly transferred between the intermediate electrode and the molten salt or inside the intermediate electrode, and is not necessarily limited to the structure of the present embodiment.

  For example, as shown in FIG. 4, the intermediate electrode 140 can be configured to include a conductive electrode main body 142 and an ion conductive solid electrolyte 144 that covers the electrode main body 142. In FIG. 4, the configuration other than the intermediate electrode 140 is the same as in FIG. 1, and therefore, the same components as those in FIG. 1 are denoted by the same reference numerals and detailed description thereof is omitted (FIGS. 5 and subsequent drawings). The same applies to the above).

As the ion conductive solid electrolyte 144, a lithium ion conductive solid electrolyte widely used in secondary batteries or the like can be preferably used. In the present embodiment, Li ₂ O—SiO ₂ —La ₂ O ₃ or the like can be used. Lithium ion conductive glass exemplified as is used. The solid electrolyte 144 is preferably a material having high conductivity and durability at high temperatures and sufficient resistance to thermal shock, and may be a ceramic or a polymer material in addition to glass.

  The electrode body 142 includes a metal material obtained by reducing the same kind of cation as the charge carrier of the solid electrolyte 144. In the present embodiment, the electrode body 142 is made of liquid lithium metal.

  According to such a metal recovery apparatus including the intermediate electrode 140, as shown in FIG. 5, in the elution step of energizing between the anodic dissolution electrode 20 and the intermediate electrode 140 so that the intermediate electrode 140 functions as a cathode. , Lithium ions contained in the molten salt of LiCl—KCl are reduced in the intermediate electrode 140, and the generated lithium metal is taken into the solid electrolyte 144. That is, the following reaction occurs in the anodic dissolution electrode 20 and the intermediate electrode 140.

Anodizing electrode 20 (anode): AB → B + A (I) + e ⁻
Intermediate electrode (cathode) 140: Li ⁺ + e ⁻ → Li
Next, in a deposition step in which current is passed between the intermediate electrode 140 and the recovery electrode 30 so that the intermediate electrode 140 functions as an anode, the lithium metal of the electrode body 142 becomes ions as shown in FIG. 144 and fed into the molten salt. That is, the following reaction occurs at the intermediate electrode 140 and the recovery electrode 30.

Intermediate electrode (anode) 140: Li → Li ⁺ + e ⁻
Recovery electrode (cathode) 30: A (I) + e ⁻ → A
The solid electrolyte 144 is only required to be capable of bidirectional passage of a cation as a charge carrier while isolating the electrode main body 142 and the external molten salt m, and is appropriately selected according to the type of the electrode main body 142 and the molten salt. Selectable. For example, a solid electrolyte 144 that uses an alkali metal other than lithium ions (for example, Na ⁺ ion conductive β-alumina) as a charge carrier can also be used.

Moreover, the electrode main body 142 should just be able to transfer an electric charge between molten salt m through the solid electrolyte 144, and is not limited to the said embodiment. For example, as shown in FIG. 7, the intermediate electrode 240 is added to the solid electrolyte 244 made of a lithium glass container.
In-electrode molten salt 242a different from
And a built-in electrode 242b made of a solid metal material is immersed in the molten salt 242a in the electrode. For example, when LiCl-KCl is used as the molten salt m, the in-electrode molten salt 242a is obtained by adding XCl or YCl to LiCl-KCl (that is, including X ions or Y ions described later). Can be used.

  That is, in the intermediate electrode 240 in the configuration shown in FIG. 7, the electrode body 242 includes the in-electrode molten salt 242a and the built-in electrode 242b.

  According to the metal recovery apparatus shown in FIG. 7, as shown in FIG. 8 (a), in the dissolution step, ions contained in the molten salt 242a in the electrode are reduced on the built-in electrode 242b, and the lower order. Ions are supplied into the molten salt 242a in the electrode. Then, as shown in FIG. 8B, in the precipitation step, even when the low-order ions are oxidized, they return to the original ions. That is, the following reaction occurs inside the intermediate electrode 240.

(Dissolution step) Built-in electrode (cathode) X (II) + e ⁻ → X (I)
(Deposition step) Built-in electrode (anode) X (I) → X (II) + e ⁻
In the anodic dissolution step, the lithium ions (cations) contained in the molten salt m in the electrolytic cell 10 balance the charge between the molten salt m and the molten salt 242a in the electrode. ), The molten salt m in the electrolytic cell 10 moves from the molten salt 242a in the electrode to the molten salt 242a in the electrode, and in the precipitation step, as shown in FIG. To the molten salt m.

  Thus, by using the oxidation-reduction reaction between two ions having different valences contained in the molten salt 242a in the electrode, the same effect as that of the metal recovery apparatus shown in FIG. 1 can be obtained. Examples of the redox pair of the in-electrode molten salt 242a include Fe (III) / Fe (II) and Cu (II) / Cu (I). The built-in electrode 242b is not limited as long as the redox reaction occurs reversibly.

  In the metal recovery method described above, if there is a concern about the leveling / disproportionation reaction (for example, 2Fe (III) + Fe⇔3Fe (II)) in the molten salt 242a in the electrode, FIG. As shown in FIG. 9B, ions contained in the molten salt 242a in the electrode are subjected to cathodic reduction on the built-in electrode 242b to be precipitated as metal. As shown in FIG. Oxidation (anodic dissolution) may be restored to the original ion. The reaction inside the intermediate electrode 240 in this case is as follows.

(Dissolution step) Built-in electrode (cathode) Y (I) + e ⁻ → Y
(Precipitation step) Built-in electrode (anode) Y → Y (I) + e ⁻
Thus, instead of using the oxidation-reduction reaction between two ions having different valences contained in the molten salt, the metal recovery apparatus shown in FIG. Similar effects can be achieved.

  As the molten salt 242a in the electrode in this case, for example, Fe (II) / Fe (Fe precipitation / dissolution), Ag (I) / Ag (Ag precipitation / dissolution), and the like can be considered. Can be used an Fe bar or Ag plate of sufficient size (ie, an amount that does not disappear after elution from the anode).

It is a schematic block diagram of the metal collection | recovery apparatus which concerns on one Embodiment of this invention. It is a figure which shows 1 process of the metal recovery method using the metal recovery apparatus shown in FIG. It is a figure which shows another 1 process of the metal collection | recovery method using the metal collection | recovery apparatus shown in FIG. It is a schematic block diagram of the metal collection | recovery apparatus which concerns on other embodiment of this invention. It is a figure which shows 1 process of the metal collection | recovery method using the metal collection | recovery apparatus shown in FIG. It is a figure which shows another 1 process of the metal collection | recovery method using the metal collection | recovery apparatus shown in FIG. It is a schematic block diagram of the metal collection | recovery apparatus which concerns on other embodiment of this invention. It is a figure which shows an example of the metal recovery method using the metal recovery apparatus shown in FIG. 7, (a) has shown the elution step, (b) has each shown the precipitation step. It is a figure which shows the other example of the metal recovery method using the metal recovery apparatus shown in FIG. 7, (a) has shown the elution step, (b) has each shown the precipitation step.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal collection | recovery apparatus 10 Electrolysis tank 20 Electrode for anodic dissolution 22 Holding part 30 Collection electrode 40 Intermediate electrode 42 Gas chamber 44 Electrode member 46 DC power supply 48 Switching element 140 Intermediate electrode 142 Electrode body 144 Solid electrolyte 240 Intermediate electrode 242 Electrode body 242a Molten salt in electrode 242b Built-in electrode w Object to be treated m Molten salt

Claims (8)

A metal recovery device for recovering metal contained in a workpiece,
An electrolytic cell capable of storing molten salt;
An anodic dissolution electrode disposed in the electrolytic cell, a recovery electrode and an intermediate electrode,
The electrode for anodic dissolution has a holding part for holding an object to be processed,
Energization is performed between the anodic dissolution electrode and the intermediate electrode so that the anodic dissolution electrode and the intermediate electrode function as an anode and a cathode, respectively, with the molten salt stored in the electrolytic cell. By leaching the metal contained in the object to be processed into the molten salt,
After the energization is completed, the eluted metal ions are supplied to the recovery electrode by energizing the intermediate electrode and the recovery electrode so that the intermediate electrode and the recovery electrode function as an anode and a cathode, respectively. Metal recovery equipment that deposits as metal or alloy. The intermediate electrode is a gas electrode;
By energization between the anodic dissolution electrode and the intermediate electrode, anions are generated from the supply gas to the intermediate electrode and supplied into the molten salt,
The metal recovery apparatus according to claim 1, wherein the anion in the molten salt is taken in by an oxidation reaction at the intermediate electrode by energization between the intermediate electrode and the recovery electrode. The metal recovery apparatus according to claim 2, wherein the supply gas to the intermediate electrode is a mixed gas of hydrogen and hydrogen chloride. The intermediate electrode includes an ion conductive solid electrolyte, and an electrode body installed inside the solid electrolyte,
By energization between the anode and the intermediate electrode, a cation of the same type as the charge carrier of the solid electrolyte contained in the molten salt is taken inside the solid electrolyte,
The metal recovery apparatus according to claim 1, wherein a cation is supplied into the molten salt from the inside of the solid electrolyte through the solid electrolyte by energization between the intermediate electrode and the cathode. The metal recovery apparatus according to claim 4, wherein the solid electrolyte of the intermediate electrode is lithium ion conductive glass. The metal recovery apparatus according to claim 4, wherein the electrode body includes a metal material obtained by reducing a cation of the same kind as the charge carrier of the solid electrolyte. The said electrode main body is a metal collection | recovery apparatus of Claim 4 or 5 provided with the solid internal electrode and the molten salt in an electrode in which this internal electrode is immersed. A metal recovery method for recovering metal contained in a workpiece,
An electrode immersing step of immersing the electrode for anodic dissolution that retains the object to be processed, and the electrode for recovery and the intermediate electrode in the molten salt by storing the molten salt in an electrolytic cell;
By supplying an electric current between the anodic dissolution electrode and the intermediate electrode so that the anodic dissolution electrode and the intermediate electrode function as an anode and a cathode, respectively, the metal contained in the object to be processed is contained in the molten salt. An elution step for anodic elution,
After completion of the elution step, the eluted metal ions are removed from the cathode by energizing the intermediate electrode and the recovery electrode so that the intermediate electrode and the recovery electrode function as an anode and a cathode, respectively. A metal recovery method comprising: a precipitation step of precipitating as a metal or alloy.