JP2015183225A - Apparatus and method for recovering rare metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently recover rare metal such as Nd and Dy at low cost using a compact and highly efficient apparatus for recovering rare metal.SOLUTION: The apparatus for recovering rare metal includes an electrolysis tank 10 filled with a molten salt 12 containing a rare metal constituent, an electric furnace 11 provided around the electrolysis tank, an anode 13 disposed in the electrolysis tank, and a cathode 14 disposed in the electrolysis tank and having a working electrode and a heating device 2 provided inside the working electrode 1. Rare metal 4 deposited on the working electrode is recovered as a liquid alloy 5 by keeping a temperature of the working electrode 1 at a temperature higher than a temperature of the molten salt 12, the temperature being a recovery temperature at which the rear metal bonds a constituent of the working electrode 1 to form a liquid alloy.

Description

  The present invention relates to a rare metal recovery apparatus and recovery method for recovering rare metals used in high performance magnets and the like.

  In recent years, rare metals used in high-performance magnets (mainly Nd (neodymium) and Dy (dysprodium)) are limited in their origins, so the need for recycling technology to collect and reuse rare metals from the viewpoint of stable supply The nature is increasing. As this recycling technique, a rare metal recovery method using a wet separation method or a molten salt electrolysis method is conventionally known.

  In the rare metal recovery method using the wet separation method, oxalic acid or the like is added to the solution containing the rare metal to be recovered to generate an oxalate precipitate, and then the precipitate is heated and dried to generate a rare metal oxide. After that, the rare metal was recovered by performing purification and concentration by a wet separation method such as a solvent extraction method or an ion exchange method.

  In addition, a rare metal recovery method using a molten salt electrolysis method has been proposed in which a rare metal metal deposited on a cathode is reacted with an electrode base material to lower the melting point and recovered as a liquid alloy (Patent Document 1). .

JP 2012-214855 A

  In the rare metal recovery method using the conventional molten salt electrolysis method described above, the rare metal metal deposited on the cathode is reacted with the electrode base material to lower the melting point, and is recovered as a liquid alloy. It is necessary to maintain the reaction temperature at a temperature at which the reaction is liquefied by the eutectic of the deposited metal and the cathode base metal. For example, when Nd or Dy used for a high-performance magnet is reacted with the cathode, the temperature of the electrolytic cell needs to be maintained at 700 to 900 ° C.

  However, in order to maintain an electrolytic cell containing a large amount of molten salt at 700 ° C. or higher, a large-capacity heating device that consumes enormous energy is required, and the electrolytic cell container and the accompanying constituent materials have high heat resistance. Since a material having corrosion resistance has to be used, there is a problem that the facility is enlarged and the facility cost and the operating cost are increased, and as a result, the recovery cost is increased.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a compact and highly efficient rare metal recovery apparatus and recovery method that can efficiently recover rare metals such as Nd and Dy.

  In order to solve the above problems, a rare metal recovery apparatus according to the present invention is arranged in an electrolytic cell filled with a molten salt containing a rare metal component, a heating furnace provided around the electrolytic cell, and the electrolytic cell. A rare metal recovery device comprising a working anode disposed in the electrolytic cell and a cathode having a heating device provided inside the working electrode, wherein the temperature of the working electrode is set to the molten salt And the rare metal metal deposited on the working cathode is recovered as a liquid alloy by maintaining the recovery temperature at which the rare metal metal is combined with the components of the working electrode to form a liquid alloy. And

  Moreover, the rare metal recovery method according to the present invention includes an electrolytic cell filled with a molten salt containing a rare metal component, a heating furnace provided around the electrolytic cell, an anode disposed in the electrolytic cell, A rare metal recovery method comprising: a working electrode disposed in an electrolytic cell; and a cathode having a heating device provided inside the working electrode, wherein the rare metal deposited on the working cathode is recovered as a liquid alloy, The temperature of the working electrode of the cathode is higher than the temperature of the molten salt, and the rare metal metal is held at a recovery temperature at which a component of the working electrode is combined to form a liquid alloy.

  According to the present invention, it is possible to provide a compact and highly efficient rare metal recovery apparatus and recovery method capable of recovering rare metals such as Nd and Dy efficiently and at low cost.

Schematic of the rare metal collection | recovery apparatus which concerns on 1st Embodiment. The block diagram of the cathode which concerns on 2nd Embodiment. (A) to (c) is a configuration diagram for explaining the consumption state of the cathode according to the third embodiment. The block diagram of the cathode which concerns on 4th Embodiment. The block diagram of the cathode which concerns on 5th Embodiment.

Hereinafter, embodiments of a rare metal recovery apparatus and recovery method according to the present invention will be described with reference to the drawings.
[First Embodiment]
A rare metal recovery apparatus and recovery method according to the first embodiment will be described with reference to FIG.

(Constitution)
As shown in FIG. 1, the rare metal recovery apparatus according to the first embodiment is disposed around an electrolytic cell 10 filled with a molten salt 12 made of LiCl, KCL, CaCl ₂ or the like, and the electrolytic cell 10. An electric furnace 11 which is a heating furnace, an anode 13 made of carbon, for example, and a cathode 14 having a working electrode 1 made of Fe, Ni or the like disposed in the electrolytic cell 10 are configured.

  The cathode 14 is composed of a working electrode 1 and a heating device 2 installed therein, and the working electrode 1 includes a lead wire 7 for maintaining an electrical connection. The heating device 2 is connected to the power source 15 by a lead wire.

(Function)
In the rare metal recovery apparatus configured as described above, when recovering the rare metal, the molten salt 12 in the electrolytic cell 10 is heated by, for example, an electric furnace 11 which is a heating furnace. Although the molten salt 12 varies depending on the material of the molten salt 12 to be used, it is generally heated to 500 to 700 ° C.

  In the cathode 14, the working electrode 1 is heated by the heating device 2 to a recovery temperature higher than the temperature of the molten salt 12 in the electrolytic cell 10. The recovery temperature of the working electrode 1 is heated so as to be close to the eutectic temperature of Nd or Dy and the component (Fe or Ni) of the working electrode 1. The recovery temperature varies depending on the combination of Nd or Dy and the components of the working electrode 1, but is preferably as high as possible so that the soundness of the material of the working electrode 1 can be maintained. The specific recovery temperature is approximately 700 to 900 ° C.

In this state, the rare metal 3 in the molten salt 12 to be collected is deposited on the surface of the working electrode 1 as a metal precipitate (rare metal metal) 4. These reactions are represented by the following formulas (1) and (2).
Nd ³⁺ + 3e ⁻ = Nd (1)
Dy ³⁺ + 3e ⁻ = Dy (2)

  The metal deposit 4 of Nd or Dy deposited on the surface of the working electrode 1 immediately combines with the component (Fe or Ni) of the working electrode 1 to form the liquid alloy 5 and is dropped on the bottom of the electrolytic cell 10. The dripping material is collected by a suction tool or the like (not shown).

(effect)
According to the present embodiment, by providing the heating device 2 on the cathode 14 and maintaining only the cathode 14 at a high recovery temperature, there is no need to heat the entire electrolytic cell 10 to a high temperature, and the recovery device can be reduced in size and recovered. Work efficiency and cost reduction can be achieved.

[Second Embodiment]
A rare metal recovery apparatus and recovery method according to the second embodiment will be described with reference to FIG.
The cathode 14 according to the second embodiment includes an insulator 6 in which the heating device 2 is inserted, and a working electrode 1 provided so as to cover the periphery of the insulator 6.

Thus, even if the electrolytic purification proceeds and the working electrode 1 reacts with the metal deposit 4 and is consumed, the heating device 2 is not exposed and the physical and electrical insulation is maintained. 14 soundness can be maintained.
According to this embodiment, since the insulator 6 is disposed between the heating device 2 and the working electrode 1, the soundness of the cathode 14 including the heating device 2 can be maintained over a long period of time.

[Third Embodiment]
A rare metal recovery apparatus and recovery method according to a third embodiment will be described with reference to FIG.
In the cathode 14 according to the third embodiment, the working electrode 1 is not in close contact with the insulator 6, and is placed on a base 8 provided at the lower portion of the insulator 6. It is configured to be movable.

By the way, when the electrolytic purification progresses, the working electrode 1 reacts with the metal deposit 4 and is consumed, and finally the working electrode 1 of the cathode 14 disappears and the progress of electrolysis is stopped.
Therefore, in this embodiment, as shown in FIGS. 3A to 3C, the working electrode 1 is placed on the base 8 of the insulator 6 so that it acts at the lower part of the electrolytic bath interface. Even if the electrode 1 is consumed and disappeared by electrolysis (FIGS. 3A and 3B), the working electrode 1 falls due to its own weight (FIG. 3C), and thus the electrolytic purification can be continued. .

  According to the present embodiment, the electrolysis stop due to the consumption of the working electrode 1 can be prevented, so that the recovery operation can be continued for a long time.

[Fourth Embodiment]
A rare metal recovery apparatus and recovery method according to the fourth embodiment will be described with reference to FIG.
The cathode 14 according to the fourth embodiment is provided on the insulator 6 in which the heating device 2 is inserted, the working electrode 1 provided so as to cover the periphery of the insulator 6, and the lower end portion of the insulator 6. It is comprised from the concave-shaped collection | recovery container 9 made.

  By the way, in the said 1st-3rd embodiment, although the liquid alloy 5 produced | generated with the working electrode 1 has a structure dripped at the bottom part of the electrolytic cell 10, the molten salt 12 in the electrolytic cell 10 is comparatively low temperature. Therefore, the liquid alloy 5 may be solidified during the dropping process. When the liquid alloy 5 is solidified, there is a problem that subsequent removal and recovery operations become difficult.

  Therefore, in this embodiment, as shown in FIG. 4, while providing the collection container 9 which accommodates the liquid alloy 5 dripped at the lower part of the insulator 6, the heating apparatus 2 is extended to the lower end part of the insulator 6, The recovery container 9 is also configured to be heatable, whereby the liquid alloy 5 recovered in the recovery container 9 can be held in a liquid state, and the liquid alloy 5 can be easily recovered by suction or the like.

In addition, as shown in FIG. 4, you may comprise so that the working electrode 1 may be mounted in the upper surface of the collection container 9. FIG.
According to the present embodiment, the recovery container 9 is provided below the insulator 6, and the working electrode 1 and the recovery container 9 can be heated by the heating device 2, thereby further improving the efficiency of the rare metal recovery operation. Can do.

[Fifth Embodiment]
A rare metal recovery apparatus and recovery method according to a fifth embodiment will be described with reference to FIG.
In the fourth embodiment, the working electrode 1 and the collection container 9 can be heated by a single heating device 2.

  However, the recovery temperature of the working electrode 1 is preferably as high as possible so that the soundness of the cathode material can be maintained. On the other hand, if the recovery container 9 is heated more than necessary, other impurities may be mixed in, or the soundness of the container material may be impaired, and the lower the temperature of the liquid alloy 5, the lower the vapor pressure of the liquid alloy. Efficiency is improved. Therefore, it is sufficient that the liquid alloy 5 recovered in the recovery container 9 is maintained near the melting point.

Thus, since it is desirable that the heating temperatures of the working electrode 1 and the recovery container 9 are different from each other, in the fifth embodiment, as shown in FIG. 5, the heating device 17 for heating the working electrode 1 and the recovery container 9 are used. It is set as the structure which provided separately the heating apparatus 18 which heats.
According to the present embodiment, since the working electrode 1 and the recovery container 9 can be heated to their optimum temperatures, the efficiency of the rare metal recovery operation can be further improved.

  As mentioned above, although embodiment of this invention was described, this embodiment is shown as an example and is not intending limiting the range of invention. The novel embodiment can be implemented in various other forms, and various omissions, combinations, replacements, and changes can be made without departing from the spirit of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Working electrode 2, 17, 18 ... Heating device, 3 ... Rare metal component, 4 ... Metal deposit (rare metal metal), 5 ... Liquid alloy, 6 ... Insulator, 7 ... Lead wire, 8 ... Base, 9 DESCRIPTION OF SYMBOLS ... Recovery container, 10 ... Electrolytic cell, 11 ... Electric furnace (heating furnace), 12 ... Molten salt, 13 ... Anode, 14 ... Cathode, 15 ... Power supply.

Claims (6)

An electrolytic cell filled with a molten salt containing a rare metal component, a heating furnace provided around the electrolytic cell, an anode disposed in the electrolytic cell, a working electrode disposed in the electrolytic cell, and this action A rare metal recovery device comprising a cathode having a heating device provided inside the electrode,
Rare metal metal deposited on the working cathode by maintaining the temperature of the working electrode higher than the temperature of the molten salt and maintaining the recovery temperature at which the rare metal metal is combined with the components of the working electrode to form a liquid alloy. A rare metal recovery device characterized in that it is recovered as a liquid alloy.   The rare metal recovery apparatus according to claim 1, wherein the cathode includes an insulator having a heating device provided therein and a working electrode provided to cover the periphery of the insulator.   The rare metal recovery apparatus according to claim 2, wherein a base on which the working electrode is placed is provided below the insulator.   4. The rare metal recovery apparatus according to claim 2, wherein a recovery container for storing a liquid alloy is provided below the insulator.   5. The rare metal recovery apparatus according to claim 4, wherein a heating device for heating the working electrode and a heating device for heating the recovery container are separately provided in the insulator. An electrolytic cell filled with a molten salt containing a rare metal component, a heating furnace provided around the electrolytic cell, an anode disposed in the electrolytic cell, a working electrode disposed in the electrolytic cell, and this action A cathode having a heating device provided inside an electrode, and a rare metal recovery method for recovering a rare metal metal deposited on the working cathode as a liquid alloy,
A method for recovering a rare metal, characterized in that the temperature of the working electrode of the cathode is higher than the temperature of the molten salt, and the rare metal metal is held at a recovery temperature at which the component of the working electrode is combined to form a liquid alloy.

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