JP2014194056A - Apparatus and method for recovering rare earth metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process of recovering rare earth metals which enables not only extraction of rare earth metals from a rare earth magnet with molten magnesium and separation of a remaining Fe-B alloy but separation of rare earth metals and magnesium from magnesium containing the extracted rare earth metals and also executes decarbonization of rare earth metals.SOLUTION: A rare earth metal recovery apparatus is provided with a reactor 101b (lower part) for extraction of rare earth metals and a reactor 101a (upper part) for recovery of magnesium, and molten liquid magnesium is caused to extract rare earth metals from a magnet 10 containing rare earth metals in the rare earth metal extraction reactor with the inside surface made of tantalum, the remaining magnet after extraction of rare earth metals and liquid magnesium dissolved with rare earth metals are separated with e.g. a tantalum-made net 104. The rare earth metals and magnesium are recovered by evaporating magnesium from the separated liquid magnesium containing rare earth metals to transfer the magnesium to the reactor (upper part).

Description

  The present invention relates to a rare earth metal recovery device and a rare earth metal recovery method.

  Rare earth elements are indispensable materials for improving the performance of electronic products such as storage batteries, light emitting diodes, and magnets. Rare earth magnets that are typical applications of rare earth elements (for example, RE-Fe-B magnets, where RE (rare earth element) is a rare earth mainly composed of Nd and Pr and partially substituted with Dy, Ce, etc. In addition to Fe, transition elements such as Co and some elements such as Al may be substituted), which has excellent magnetic properties and high mechanical strength. In addition, it is applied to a wide range of applications such as gas magnetic field treatment equipment in chemical plants.

  Currently, rare earth magnets mounted on used products are usually discarded as iron scrap. However, since the rare earth magnets to be discarded contain a high concentration of rare earth elements that have recently been feared for stable procurement, establishment of a rare earth element recycling technology from rare earth magnets is required.

  As a background art of the rare earth element regeneration method, there is a molten metal extraction method. Magnesium (Mg) and silver (Ag) melts have the property of dissolving rare earth metals in rare earth magnets and not dissolving Fe-B alloys. Using this property, Mg or Ag is heated to a temperature higher than the melting point to make magnesium or Ag a liquid (molten metal), and by bringing the molten metal into contact with the rare earth magnet, the rare earth metal is mainly melted from the magnet. The method of extracting to the metal side is the molten metal extraction method. Unlike wet processes such as solvent extraction and molten salt electrolysis, which are applied in recycling magnetic grinding scraps generated in the magnet manufacturing process, the molten metal extraction method is a dry process that does not use acids or organic solvents. Therefore, it is expected as a rare earth metal recovery process with low environmental impact and low cost.

JP 2012-188695 A

  Rare earth magnets generally contain less than 0.08% by weight of carbon. This carbon is mixed in the rare earth magnet manufacturing process due to grinding aids, grinding oil, grinding wheel scraps, etc., and is greatly increased compared to the amount of carbon in the magnet raw material alloy. When the rare earth metal recycled from such a high-carbon rare earth magnet is used as it is as a raw material for the rare earth magnet, the magnetic properties of the rare earth magnet produced at that time are greatly deteriorated. When reusing in the magnet alloy melting step, it is essential to perform a decarburization process.

  In Patent Document 1, rare earth metal extraction using a molten metal extraction method, separation of an Mg alloy containing the extracted rare earth metal and a rare earth magnet after extraction of the rare earth metal (Fe-B is the main component), and rare earth metal A rare earth metal recovery device and a rare earth metal recovery method capable of simultaneously realizing the separation of Mg from the Mg alloy contained are disclosed. However, in the recovery apparatus and method disclosed in Patent Document 1, the recovered rare earth metal is decarburized simultaneously in a series of rare earth metal recycling processes including extraction of rare earth metal, separation with Fe-B, and separation with Mg. Is not considered at all. Therefore, the obtained rare earth metal cannot be returned to the melting process of the rare earth magnet alloy.

  Accordingly, the present invention provides a rare earth metal recovery device and a recovery method from a rare earth magnet capable of recovering rare earth metal from a rare earth magnet by a molten metal extraction method and decarburizing the rare earth metal in the recovery step. Is.

  In order to solve the above problems, in the present invention, a rare earth metal recovery device for recovering rare earth metal from a raw material containing a rare earth element, a reaction vessel (lower part) for extracting the rare earth metal by immersing the raw material having the rare earth metal in molten magnesium ), A raw material from which the rare earth metal is extracted, and a separation means for separating the liquid magnesium in which the rare earth metal is dissolved, and vaporizing the magnesium from the liquid magnesium containing the separated rare earth metal The rare earth metal recovery means for recovering the rare earth metal and the reaction vessel (upper part) for recovering the condensed magnesium by condensing or solidifying it, the reaction vessel (lower part) and the reaction vessel (upper part) comprising: It is constructed in one piece, and at least the inner surface and / or part of or part of the reaction vessel (upper and lower). It was constructed using tantalum (Ta) on a surface in contact with the rare earth metal of the separating means. Further, instead of the inner surface of the reaction vessel and the surface of the separating means contacting the rare earth metal, a member having at least a surface made of tantalum (Ta) may be put into the reaction vessel (lower part) separately.

  In order to solve the above problems, the present invention provides a rare earth metal recovery method for recovering a rare earth metal from a raw material containing a rare earth element, and an extraction step of extracting the rare earth metal by immersing the rare earth metal-containing raw material in molten magnesium. Separating the raw material from which the rare earth metal has been extracted from liquid magnesium in which the rare earth metal has been dissolved, and vaporizing the magnesium from the liquid magnesium containing the separated rare earth metal And a rare earth metal recovery step for recovering the rare earth metal, and a magnesium recovery step for recovering the vaporized magnesium by condensing or solidifying the magnesium, and liquid magnesium in which the rare earth metal is dissolved in any of the steps The surface was brought into contact with a member made of tantalum.

  According to the present invention, it is possible to provide a rare earth metal recovery device and recovery method using a rare earth magnet as a starting material. In addition to the extraction of rare earth metals from rare earth magnets and the separation of magnesium containing extracted rare earth metals and the remaining Fe-B alloy of rare earth magnets after extraction of rare earth metals, Separation of rare earth metals can be realized at the same time. Furthermore, a rare earth metal recovery device and a recovery method from a rare earth magnet capable of decarburizing the rare earth metal to be recovered can be provided.

It is a block diagram of the rare earth metal collection | recovery apparatus which concerns on Example 1 of this invention. It is the 1st schematic diagram of the rare earth metal recovery method concerning Example 1 of the present invention. It is a 2nd schematic diagram of the rare earth metal collection | recovery method which concerns on Example 1 of this invention. It is a 3rd schematic diagram of the rare earth metal collection | recovery method which concerns on Example 1 of this invention. It is the 4th schematic diagram of the rare earth metal recovery method concerning Example 1 of the present invention. It is a 5th schematic diagram of the rare earth metal recovery method which concerns on Example 1 of this invention. It is a schematic diagram which shows a part of rare earth metal collection | recovery method based on Example 3 of this invention. It is a schematic diagram which shows a part of rare earth metal collection | recovery method concerning the comparative example of this invention. It is an Ellingham figure of carbide of Mg, Fe, Ta, and rare earth metals. It is an Ellingham diagram of oxides of Mg, Fe, Ta, Nd, and Dy.

  Hereinafter, embodiments of a rare earth metal recovery device and a rare earth metal recovery method according to the present invention will be described in detail. Note that, in the drawings for describing the embodiments for implementation, the same members are denoted by the same reference symbols in principle, and repeated description thereof is omitted.

In this embodiment, an example of a rare earth metal recovery apparatus and method for recovering rare earth metal from a rare earth magnet and decarburizing the rare earth metal will be described.
FIG. 1 is a configuration diagram of a rare earth metal recovery device of the present embodiment.
The rare earth metal recovery device 100 includes a reaction vessel (upper) 101a, (lower) 101b made of iron or an iron alloy, a flange 102 for hermetically sealing the reaction vessel (upper) 101a and (lower) 101b, and a reaction vessel (lower) 101b. Heater 103 for heating, net 104 made of tantalum, (evacuation, gas introduction, closing) switching valve 105, filter 106, vacuum pump 107, cooling mechanism 108 for reaction vessel (upper) 101a, (exhaust, closing) switching A valve 109. Here, the entire inner surface of the reaction vessel (upper part) 101a and (lower part) 101b is made of tantalum. The reaction vessel (upper part) 101a and the (lower part) 101b have a cylindrical shape with a taper that maximizes the diameter of the central part (102 part of the airtight seal flange). The reaction vessel (upper part) 101 a and the reaction vessel (lower part) 101 b are integrally formed by an airtight seal flange 102. The hermetic seal flange 102 has a water-cooled jacket structure, and the O-ring for hermetic sealing is sufficiently cooled. The reason why the reaction vessels (upper) 101a and (lower) 101b, 104 are made of tantalum (Ta) is to perform decarburization of rare earth metal by forming tantalum carbide.

  Based on data described in “CRC Handbook of Chemistry and Physics, 66th ed .; CRC Press: Boca Raton, FL, 1985; D50-D93.”, Carbides such as tantalum (Ta), rare earth elements, magnesium, iron, etc. The Ellingham diagram is shown in FIG. 5, and the Ellingham diagram of the oxide is created in FIG. Based on the Ellingham diagram of carbides, tantalum has a higher reactivity with carbon than rare earth metals, and it can be seen that rare earth metals can be decarburized by forming carbides. In addition, when a thin oxide film is formed on the tantalum surface, carbide is not formed, but magnesium, which is a rare earth metal extraction medium, reduces the tantalum oxide film based on the oxide Ellingham diagram, and the oxide film is removed. Thus, it can be seen that tantalum can form carbides.

At the beginning of the recycling process, magnesium (solid) 20 is installed in the reaction vessel (lower part) 101b. A circular tantalum net 104 is disposed thereon, and a rare earth magnet 10 is disposed thereon. In order to prevent the rare earth magnet 10 from passing through the tantalum mesh 104 and dropping downward, the tantalum mesh 104 having a mesh size smaller than that of the charged shape of the rare earth magnet 10 is used. Here, tantalum on the inner surfaces of the reaction vessels (upper) 101a and (lower) 101b and the carbon concentration in the tantalum net 104 are not particularly limited, but stable tantalum carbide is Ta ₂ C or From the understanding that it is TaC, it is preferably 7.2% or less, more preferably 3.2% or less. In this example, a reaction vessel having an inner surface made of tantalum having a carbon concentration of 20 ppm and a net made of tantalum were used.

FIG. 2A is a schematic diagram showing a part of the rare earth metal recovery method of the first embodiment of the present invention.
Magnesium (solid) 20 was placed in a reaction vessel (lower part) 101b, a tantalum net 104 was placed thereon, and a raw material obtained by slicing the rare earth magnet 10 into an appropriate shape was placed thereon. A rare earth magnet consisting of Nd 21.2%, Dy 4.16%, Pr 6.00%, Co 0.88%, Cu 0.11%, Al 0.22%, C 0.066%, O 0.52%, B 0.93%, balance Fe, and magnesium as the starting material Twice the weight was added. (Exhaust, closed) The switching valve 109 is closed, and the reaction vessels 101a and 101b are evacuated by the vacuum pump 107. Then, the switching valve 105 is switched to introduce argon gas and reach 1 atm. Closed) The switching valve 109 was opened and sufficiently replaced with argon gas. Argon gas was continuously supplied to the reaction vessel (upper part) 101a and (lower part) 101b, and the heater 103 for heating was heated in an argon gas stream.

FIG. 2B is a schematic diagram showing a part of the rare earth metal recovery method of the first embodiment of the present invention.
The magnesium (solid) 20 portion is heated to a temperature of 1000 ° C., and the magnesium (solid) 20 is melted to form magnesium (liquid) 21. At this time, the tantalum net 104 moves downward. Thus, the rare earth magnet 10 was immersed in the magnesium (liquid) 21. The outer shape of the circular tantalum net 104 is large enough so that the magnesium (solid) 20 is completely melted to become the magnesium (liquid) 21 and the rare earth magnet 10 on the net is completely immersed in the magnesium (liquid). It has been adjusted.

FIG. 2C is a schematic diagram showing a part of the rare earth metal recovery method of the first embodiment of the present invention.
By bringing the rare earth magnet 10 into contact with the magnesium (liquid) 21 at a temperature of 1000 ° C., the rare earth metal component in the rare earth magnet 10 moves (extracts) to the magnesium (liquid) 21 side. As a result, the rare earth magnet 10 becomes an alloy 11 mainly composed of iron and boron, and the magnesium (liquid) 21 becomes a magnesium-rare earth metal alloy 23. The rare earth metal extraction time varies depending on the shape of the rare earth magnet 10. For example, if the rare earth magnet is finely pulverized and charged, the surface area increases, and the diffusion distance of the rare earth metal in the magnet decreases and the extraction time increases. In this example, a rare earth magnet was sliced and used. Although the extraction time is about 1 to 6 hours as a guide, it is a time for extracting the rare earth metal from the rare earth magnet 10 sufficiently.

  In the rare earth metal recovery method of this embodiment, in the step of extracting the rare earth metal component to the magnesium (liquid) 21 side, the rare earth metal extraction reaction is preferably performed at a temperature of 650 ° C. or higher and 1000 ° C. or lower. The reason why the temperature is 650 ° C. or higher is that the melting point of magnesium is 650 ° C., and that the temperature is 1000 ° C. or lower is to suppress the evaporation of neodymium as much as possible by setting the melting point of neodymium to 1,024 ° C. or lower.

FIG. 2D is a schematic diagram showing a part of the rare earth metal recovery method of the first embodiment of the present invention.
After the rare earth metal is sufficiently extracted into magnesium (liquid), the heating temperature is lowered to 660 ° C., (evacuation, gas introduction, closing) switching valve 105 and (exhaust, closing) switching valve 109 are closed, and the argon gas is The supply was stopped. Next, the reaction vessel (upper part) 101a and the (lower part) 101b are evacuated from the upper part by the vacuum pump 107 to vaporize only magnesium (gas) 22 from the magnesium-rare earth metal alloy 23, and at the same time, the reaction container (upper part). 101a was cooled to a temperature of 650 ° C. or lower by the cooling mechanism 108, so that magnesium (solid) 20 was precipitated and solidified on the inner wall surface of the reaction vessel (upper part) 101a. Here, water cooling by water shower was used as the cooling mechanism.

  FIG. 2E is a schematic diagram showing a part of the rare earth metal recovery method of the first embodiment of the present invention.

  By further separating and collecting the magnesium (gas) 22 from the magnesium-rare earth metal alloy 23 by vacuum distillation, the magnesium is precipitated and solidified as (solid) 20 on the inner wall surface of the reaction vessel (upper part) 101a. It was recovered. At the same time, the remaining alloy 11 mainly composed of iron and boron after the rare earth metal 12 is extracted from the rare earth magnet 10 is converted into magnesium (gas) 22 from the magnesium-rare earth metal alloy 23 on the tantalum net 104. The remaining rare earth metal 12 after being separated by distillation was recovered at the bottom of the reaction vessel (lower part) 101b. That is, a rare earth metal 12, an alloy 11 mainly composed of iron and boron, and magnesium (solid) 20 are obtained from the rare earth magnet 10 and magnesium (solid) 20, and the three recovered items are separated from each other and recovered. We were able to. Magnesium (solid) 20 is recycled in this step.

  Here, the heating temperature of the magnesium-rare earth metal alloy 23 is set to 660 ° C. or more, which is the melting point temperature of magnesium, which is 650 ° C. or more, and the rare earth metal remaining in the reaction vessel (lower part) and the inner surface are made of tantalum. This is because it is preferable to set the temperature just above the melting point in order to reduce the adhesion with the reaction vessel and facilitate recovery. If the amount of magnesium in the magnesium-rare earth metal alloy 23 continues to decrease, the magnesium-rare earth metal alloy 23 solidifies, but magnesium is vaporized by sublimation. (Evacuation, gas introduction, closing) By installing the filter 106 between the switching valve 105 and the vacuum pump 107, magnesium can be prevented from going to the vacuum pump side.

  Finally, from the inside of the reaction vessel (lower part) 101b made of tantalum, the rare earth metal 12 from the inside of the tantalum net 104, the alloy 11 mainly composed of iron and boron, and the reaction vessel (upper part) 101a from the tantalum net 104. Magnesium (solid) 20 was recovered. The magnesium (solid) 20 in the reaction vessel (upper part) 101a can be reused.

  As a result of this example, a sponge-like rare earth metal composed of Nd, Pr, and Dy was obtained as the rare earth metal 12 in the reaction vessel (lower part) 101b whose inner surface was made of tantalum. Specifically, it was a rare earth metal having a purity of 98.0% including Nd 72.4%, Dy 4.7%, and Pr 20.9%, and the carbon content was 410 ppm. The recovery rate of the rare earth metal from the charged rare earth magnet 10 was 92%. Although about 0.2% Fe impurities remained in the collected rare earth metal alloys, these alloys are particularly problematic because they are used as rare earth metal raw materials for the production of RE-Fe-B magnets. There is no.

In this example, magnesium was vaporized from the magnesium-rare earth metal alloy 23 of Example 1, and the heating temperature was changed to 750 ° C.
As a result of this example, as in Example 1, a rare earth with a purity of 97.4% containing Nd 71.7%, Dy 5.0%, Pr 20.7% as a rare earth metal 12 in a reaction vessel (lower part) 101b whose inner surface is made of tantalum. Metal was recovered and the carbon content was 370 ppm. Compared with Example 1, the inner surface of the rare earth metal 12 was firmly fixed to the reaction vessel (lower part) 101b made of tantalum, and the recovery rate of the rare earth metal from the charged rare earth magnet 10 was 80%.

  In the rare earth metal recovery method of the present embodiment, in the step of recovering the rare earth metal and recovering magnesium, the vaporization of magnesium is preferably performed at a temperature of 650 ° C. or higher and 750 ° C. or lower. Here, 650 ° C. or higher is because the melting point of magnesium is 650 ° C., and 750 ° C. or lower reduces adhesion between the remaining rare earth metal and the reaction vessel made of tantalum. This is to facilitate recovery.

FIG. 3 is a schematic view showing a part of the rare earth metal recovery method of the third embodiment of the present invention.
An experiment was performed under the same conditions as in Example 1 using a reaction vessel (lower part) 120b and (upper part) 120a whose inner surfaces had a fin structure on the inner wall and made of tantalum. The reason why the inner wall of the reaction vessel 120 has a fin structure is to increase the contact frequency between the rare earth metal and tantalum and to further reduce the carbon content in the rare earth metal 12 as compared with the first embodiment. The same fin structure is also provided on the inner wall of the reaction vessel (upper) (lower). After the first treatment, the reaction vessel (upper) can be used as the reaction vessel (lower) after the second treatment. It is for doing so.

As a result of this example, the purity containing Nd 72.1%, Dy 4.8%, and Pr 21.2% as rare earth metal 12 in the reaction vessel (lower part) 120b whose inner surface is made of tantalum and has a fin structure as in Example 1. 98.1% rare earth metal was recovered and the carbon content was 300 ppm. The recovery rate of the rare earth metal from the charged rare earth magnet 10 was 90%.
[Comparative Example 1]

FIG. 4 is a schematic diagram showing a part of a rare earth metal recovery method implemented as a comparative example in order to evaluate the present invention.
In this example, the experiment was performed under the same conditions as in Example 1 with the reaction vessel (upper) 130a and (lower) 130b and the net 131 made of steel. A steel reaction vessel 130 and a steel net 131 having a carbon concentration of 0.19% were used.

  As a result of this comparative example, as in Example 1, a rare earth metal having a purity of 97.0% containing Nd 71.6%, Dy 4.5% and Pr 20.9% was recovered as a rare earth metal 12 in a steel reaction vessel (lower part) 130b. The carbon content was 1.56%. The recovery rate of the rare earth metal from the charged rare earth magnet 10 was 87%.

  The carbon content of the obtained rare earth metal 12 was increased as compared with the carbon content in the rare earth magnet 10 initially charged, but based on the Ellingham diagram of carbide, the rare earth metal component in the rare earth magnet was changed to magnesium. This is probably because the extraction step, the step of vaporizing magnesium in the magnesium-rare earth metal alloy, or the elution of the carbon in the reaction vessel to the rare earth element side after the magnesium was vaporized.

  Among the experimental results of Examples 1 to 3 and Comparative Example 1, the rare earth metal purity, the rare earth metal recovery rate, and the carbon content in the recovered material are summarized in Table 1. From this, it can be seen that the reaction vessel 101 whose inner surface is made of tantalum and the net 104 contribute to the decarburization of the rare earth metal.

As described above, in the rare earth metal recovery apparatus and method of the present invention described above, the magnet may be scrap generated in the rare earth magnet manufacturing process or a waste magnet taken out from a used product.
Also, by using tantalum super micro sieve (small sieve) instead of tantalum mesh, not only solid scrap (bulk) rare earth magnet but also rare earth magnet powder (eg magnet processing scrap) rare earth Metal recovery is also possible.

  The used product may be a hard disk drive device, a motor for home appliances / industrial products, a compressor, a hybrid vehicle, a plug-in hybrid vehicle, an electric vehicle motor, an electric power steering motor for the vehicle, and the like.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

10 Rare earth magnet 11 Alloy mainly composed of iron and boron 12 Rare earth metal 20 Magnesium (solid)
21 Magnesium (liquid)
22 Magnesium (gas)
23 Magnesium-rare earth metal alloy 100 Rare earth metal recovery device 101a Reaction vessel made of iron or iron alloy whose inner surface is tantalum (upper part)
101b Reaction vessel made of iron or iron alloy with inner surface of tantalum (lower part)
102 Airtight seal flange 103 Heating heater 104 Tantalum net 105 (evacuation, gas introduction, closing) switching valve 106 filter 107 vacuum pump 108 cooling mechanism 109 (exhaust, closing) switching valve 109
120a Reaction vessel (upper part) with inner surface made of tantalum with fin wall
120b Reaction vessel made of tantalum on the inner surface with fin structure on the inner wall (lower part)
130a Steel reaction vessel (top)
130b Steel reaction vessel (bottom)
131 Steel mesh

Claims (11)

In a rare earth metal recovery device that recovers rare earth metals from raw materials containing rare earth elements,
A first container for extracting the rare earth metal by immersing a raw material having the rare earth metal in molten magnesium;
A separation means for separating the raw material from which the rare earth metal has been extracted from liquid magnesium in which the rare earth metal is dissolved;
Rare earth metal recovery means for recovering the rare earth metal by evaporating the magnesium from the liquid magnesium containing the separated rare earth metal;
A second container for condensing or solidifying the vaporized magnesium and recovering, and the first container and the second container are integrally configured,
A rare earth metal recovery apparatus, wherein tantalum (Ta) is used on a surface of the first container, the second container, or the separation means that contacts the rare earth metal. The rare earth metal recovery device according to claim 1,
The separation means is a rare earth metal recovery device on which a raw material containing the rare earth element is placed, at least the surface of which is a tantalum net or sieve or a basket. The rare earth metal recovery device according to claim 1,
Rare earth metal recovery characterized in that one sealed container is formed by combining the openings of the first container and the second container, and the inside of the sealed container is provided with a mechanism for evacuating an argon atmosphere or evacuating. apparatus. The rare earth metal recovery device according to claim 1,
The rare earth metal recovery apparatus, wherein both the first container and the second container are made of iron or iron alloy whose inner surface is tantalum. The rare earth metal recovery device according to claim 1,
The first container and the second container each have a projection made of tantalum at least on the inner surface on the inner wall. In the rare earth metal recovery method for recovering rare earth metals from raw materials containing rare earth elements,
An extraction step of extracting the rare earth metal by immersing the raw material having the rare earth metal in molten liquid magnesium;
A separation step of separating the raw material from which the rare earth metal has been extracted from liquid magnesium in which the rare earth metal is dissolved;
A rare earth metal recovery step of recovering the rare earth metal by vaporizing the magnesium from the liquid magnesium containing the separated rare earth metal;
A magnesium recovery step of recovering the vaporized magnesium by condensing or solidifying it, and
A method for recovering a rare earth metal, characterized in that in any of the steps, the liquid magnesium in which the rare earth metal is dissolved is brought into contact with a member having a surface made of tantalum. In the rare earth metal recovery method according to claim 6,
The method for recovering a rare earth metal, wherein the member having a surface made of tantalum is a container made of tantalum having an inner surface for holding the liquid magnesium in the extraction step. The rare earth metal recovery method according to claim 7,
The container has a protrusion made of tantalum at least on the inner surface on the inner wall. In the rare earth metal recovery method according to claim 6,
In the extraction step, a rare earth metal extraction reaction is performed at a temperature of 650 ° C. or higher and 1000 ° C. or lower. In the rare earth metal recovery method according to claim 6,
In the extraction step, a tantalum net or sieve or a basket as the tantalum member is immersed in the liquid magnesium,
In the separation step, the raw material from which the rare earth metal has been extracted is separated from the rare earth metal by a tantalum net, a sieve, or a cage.   7. The rare earth metal recovery method according to claim 6, wherein in the rare earth metal recovery step and the magnesium recovery step, magnesium is vaporized at a temperature of 650 ° C. or higher and 750 ° C. or lower.

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