WO2000039514A1 - Procede et appareil permettant de fondre des dechets magnetiques a base de terres rares et alliage primaire fondu de dechets magnetiques a base de terres rares - Google Patents

Procede et appareil permettant de fondre des dechets magnetiques a base de terres rares et alliage primaire fondu de dechets magnetiques a base de terres rares Download PDF

Info

Publication number
WO2000039514A1
WO2000039514A1 PCT/JP1999/007264 JP9907264W WO0039514A1 WO 2000039514 A1 WO2000039514 A1 WO 2000039514A1 JP 9907264 W JP9907264 W JP 9907264W WO 0039514 A1 WO0039514 A1 WO 0039514A1
Authority
WO
WIPO (PCT)
Prior art keywords
earth magnet
rare earth
scrap
crucible
melting
Prior art date
Application number
PCT/JP1999/007264
Other languages
English (en)
Japanese (ja)
Other versions
WO2000039514A9 (fr
Inventor
Yoichi Hirose
Tatsuo Go
Miki Renda
Nobuhiko Kawamura
Atsushi Otaki
Original Assignee
Showa Denko K.K.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Showa Denko K.K. filed Critical Showa Denko K.K.
Priority to JP2000591371A priority Critical patent/JP4263366B2/ja
Publication of WO2000039514A1 publication Critical patent/WO2000039514A1/fr
Publication of WO2000039514A9 publication Critical patent/WO2000039514A9/fr

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B59/00—Obtaining rare earth metals
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/001—Dry processes
    • C22B7/003—Dry processes only remelting, e.g. of chips, borings, turnings; apparatus used therefor
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/16—Remelting metals
    • C22B9/22—Remelting metals with heating by wave energy or particle radiation
    • C22B9/226—Remelting metals with heating by wave energy or particle radiation by electric discharge, e.g. plasma
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces
    • F27B3/08—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces heated electrically, with or without any other source of heat
    • F27B3/085—Arc furnaces
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces
    • F27B3/10—Details, accessories, or equipment peculiar to hearth-type furnaces
    • F27B3/24—Cooling arrangements
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the present invention relates to a method of reusing an alloy having a high oxygen concentration such as scrap generated in a process of manufacturing a rare-earth magnet by a melting technique, a melting apparatus used in a recycling method, and a secondary melting method.
  • Rare-earth magnet primary molten alloy prepared in such a way that it can be used to produce magnetic alloy materials hereinafter referred to as “magnet alloys”. Background art
  • powdery scrap is generated during the process of cutting and polishing the sintered body. This is a state in which water used for cutting and powder of abrasives are mixed, and as a general method, a method of dissolving and extracting with an acid is used to recover useful metals such as rare earth elements. Already done.
  • a rare-earth metal that is extremely active in high-frequency melting, arc melting, and plasma melting is slag. Since it is difficult to separate rare earth metals from slag, a method has been proposed in which the amount of scrap added to virgin raw materials is limited and redissolved.
  • the problem with the melting method is that the surface of the molten metal is covered with the slag due to the large amount of slag generated, making it difficult to observe the state of the molten metal and measure the temperature; this slag adheres firmly to the inner wall of the crucible and grows As a result, the internal volume of the crucible is reduced, which causes a fence of the input material to be hung; the work of periodically removing the slag from the inner wall of the crucible becomes difficult, and the life of the crucible is shortened. And so on.
  • the present inventors have analyzed the cause of the low yield when the rare-earth magnet scrap is melted using a normal high-frequency induction melting furnace, and as a result, the rare-earth metal originally contained in the scrap was analyzed.
  • the oxide is separated from the scrap melt, the molten metal is also entrapped in the slag, causing the metal to be suspended in the oxide and the yield to deteriorate.
  • high oxygen concentration Slag was present in the form of slag, and the apparent amount of slag increased, resulting in a decrease in yield.
  • the method described in the above-mentioned Japanese Patent Application Laid-Open No. 8-31616 is a method in which a metal (alloy) containing a rare earth magnet constituent element as a main component, a so-called virgin raw material, is first dissolved to prepare a seed water, and then the scrap is produced.
  • This method belongs to the re-melting method rather than the scouring method in which oxides are positively removed by melting.
  • a method has been proposed in which a plasma arc is generated by separately providing a cathode torch and an anode torch (Japanese Patent Application Laid-Open Nos. 1991-1990, 3-8). 736, JP-A-7-126019, and JP-A-8-5247).
  • the plasma generated by this method is called twin-plasma.
  • the method of Japanese Patent Application Laid-Open No. Hei 7-126109 proposes a method of melting quartz glass in which impurities are not mixed from a container, and that the plasma has a high energy density and a granular silica is added to the container prior to melting. He states that laying down mosquitoes is important in achieving the desired effect.
  • Japanese Patent Application Laid-Open No. 3-25247 states that the twin torch plasma method is excellent in that it is easy to restart when melting waste such as incineration ash. As described above, it has been known that the conventional twin torch plasma dissolution method provides excellent results in dissolving oxide materials and wastes. Disclosure of the invention
  • the present invention relates to a method of separating oxides from any rare-earth magnet scrap, such as scrap generated in the process of manufacturing the rare-earth magnet and residues in the crucible generated when melting the raw material of the rare-earth magnet. Aggregation / dissolution that actively promotes separation By providing a melting and refining method, oxides can be partially separated and removed, and a very good yield can be achieved when the raw material for rare earth magnets is secondarily melted using the next vacuum high-frequency induction melting furnace. The purpose is to do so.
  • the method according to the first aspect of the present invention is the method for obtaining a raw material for producing a rare earth magnet by first melting a scrap of a rare earth magnet, wherein a water-cooled crucible or a refractory crucible in which a part or all of a molten metal holding part is insulated.
  • a scrap of rare earth magnet is charged into the crucible, and the scrap of rare earth magnet is melted by a plasma torch comprising at least one pair of an anode and a cathode provided so as to be located above the crucible.
  • the present invention relates to a method for melting scraps of rare earth magnets.
  • the apparatus for melting the rare earth scrap for carrying out the first method of the present invention is a method for holding a molten metal in a plasma arc melting furnace having a plasma torch comprising at least one pair of anode and cathode. It is characterized in that a water-cooled crucible or a refractory crucible in which part or all of the part is insulated is arranged.
  • a method according to a second aspect of the present invention is the method for obtaining a raw material for producing a rare earth magnet by first melting a scrap of the rare earth magnet, wherein the molten metal holding part has a heat insulating part and a water cooling part in a crucible.
  • the present invention relates to a method for dissolving scrap of rare earth magnets, which comprises inserting a lap and dissolving the scrap of rare earth magnets by a tundass arc or a transition type plasma arc.
  • a crucible in which a molten metal holding section includes a heat insulating part and a water cooling part is disposed in a tungsten arc or transition type plasma arc furnace. It is characterized by what has been done.
  • the method according to a third aspect of the present invention is the method for obtaining a raw material for producing a rare-earth magnet by first melting a scrap of the rare-earth magnet, wherein the molten-metal holding part is placed in a crucible having a heat insulating structure. And a tungsten arc or a transition type plasma arc is generated between a first electrode which locally covers the heat insulating surface of the crucible and a second electrode disposed above the crucible. And
  • the present invention relates to a rare earth magnet scrap melting method characterized by melting a rare earth magnet scrap.
  • the apparatus for melting the rare earth scrap for carrying out the third method of the present invention is a crucible having a heat retaining structure of a molten metal holding part in a tungsten arc or transition type plasma arc furnace, and And a second electrode disposed above the crucible.
  • the first electrode locally covers the heat insulating surface.
  • the alloy obtained by primary melting of the rare earth magnet scrap according to the present invention has a total of 10 to 40 wt% of Sm and Ce and 5 wt% of Nd for the SmCo system.
  • Fe force S 25 wt% or less Cu force 4 to 10 wt%, Zr 1 to 4 wt%, oxygen 0.1 wt% or less, and the balance is mainly Co.
  • the present invention relates to a primary molten alloy of a rare earth magnet scrap characterized by being an unavoidable impurity due to the rare earth magnet manufacturing process excluding oxygen and an invading element due to primary melting excluding Fe. .
  • Nd, Pr and Dy total 20 to 35 wt%, B force 0.9 to 1.2 wt%, and A1 force; 1 to 1 wt%, Co force 5 wt% or less, Cu force S 0.5 wt% or less, Nb force S 1 wt% or less, oxygen 0.1 wt% or less, balance Fe mainly And an inevitable impurity due to the rare earth magnet manufacturing process excluding oxygen, and an intrusion element due to primary dissolution excluding Fe, which is a primary molten alloy of a rare earth magnet scrap.
  • B force 0.9 to 1.2 wt%, and A1 force 1 to 1 wt%, Co force 5 wt% or less, Cu force S 0.5 wt% or less, Nb force S 1 wt% or less, oxygen 0.1 wt% or less, balance Fe mainly And an inevitable impurity due to the rare earth magnet manufacturing process excluding oxygen, and an intrusion element due to primary dissolution excluding Fe, which is a primary molten alloy of
  • the obtained primary molten alloy has advanced agglomeration and separation of oxides, it can be melted using the next vacuum high-frequency induction melting furnace, and the yield when reused can be extremely high.
  • melting by a tungsten arc melting furnace or a transition type plasma arc melting furnace is usually performed by a skull melting method using a copper water-cooled crucible in order to use a melting raw material as a direct counter electrode to an arc torch.
  • a shell (skull) of a solidified layer is formed on the inner surface of the water-cooled crucible by the raw material itself.
  • the NdFeB magnet is melted using a normal arc melting furnace or plasma melting furnace to scrap the SmCo magnet. If so, it becomes difficult to sufficiently raise the temperature of the molten metal above the melting point of the alloy. Therefore, if the melting is performed while keeping the temperature of the molten metal low, the deoxidizing scouring effect becomes insufficient. As a result, the yield of secondary melting of the obtained primary ingot is extremely low at 70% or less.
  • the convection of the molten metal which is essential for the separation and refining of oxides, becomes active when the temperature difference between the melting point and the molten material of the rare earth alloy material is 200 ° C or more.
  • the oxides that existed in the clamp are separated efficiently.
  • the difference in specific gravity between a rare earth magnet alloy and its rare earth oxide is small, and it is difficult to separate the oxide by flotation. That was one of the reasons why the conventional dissolution method did not reduce oxygen.
  • the viscosity difference of the alloy from the melting point is 200 ° C or more and the viscosity of the alloy becomes Very degraded. Therefore, it is considered that the separation of oxides by agglomeration and flotation progresses rapidly together with the stirring effect of plasma heating.
  • insulation generally assumes that a water-cooled crucible is made of a metal that is a good conductor of heat, and indicates the use of a contradictory poor conductor of heat. As a result, there is no skull in this heat insulating part. Specifically, a heat-insulated conductor is fixed to a part of a water-cooled crucible made of copper or the like in the molten metal holding part of the crucible to form an adiabatic part, or the crucible is made of a water-cooled metal part and a heat-insulated conductor part. Or the entire crucible is made of a poor conductor of heat.
  • Examples of poor conductors of heat include refractory materials such as alumina, zirconia, yttria, calcite, magnesia and the like and fired products of composite oxides thereof. Of these, alumina refractories are the most economical and durable. The mixing of aluminum from the refractory into the metal is controlled to a level that is not problematic by controlling the heat input from the plasma arc, etc., so that the temperature of the molten pool does not become too high. can do.
  • the molten metal holding part of the crucible is insulated to such an extent that a phenomenon such as the expansion of the molten pool occurs.
  • the heat insulation region is preferably at least 20%, more preferably at least 30%, and even more preferably at least 50% of the inner area of the crucible.
  • the entire inner area of the crucible may be insulated, or the whole may be a refractory crucible.
  • a refractory crucible it may be lined with a refractory inside a metal container (shell). S The refractories used for this lining may be fixed refractories or irregular refractories.
  • the shell can be jacket-cooled.
  • this method has the advantage of dissolving rare-earth magnet scraps with a high oxygen concentration, so it is not advisable to add virgin metal to the raw material to be dissolved.
  • part of the virgin metal preferably 30% by weight or less, is charged to the molten raw material. May be.
  • the virgin metal industrial pure iron, electrolytic iron, rare earth metals such as neodymium, rare earth mother alloys such as ferro neodymium, and ferroboron can be used.
  • the coagulation separation of oxides proceeds even if the molten metal holding time is prolonged, but its contribution is small compared to the temperature, which is not desirable from the viewpoint of productivity.
  • the skull remains, but the skull is thinner than in the case of a normal water-cooled crucible, and no skull is generated at the bottom or other portion where the refractory layer is arranged. You can do more.
  • the next raw material can be charged into the remaining skull to continue dissolution. At this time, the skull shrinks by the time the next raw material is charged, and a gap may occur between the skull and the crucible.
  • the raw materials are additionally charged as appropriate, and the molten metal is provided at the edge of the crucible and overflows from the tap hole, so that the tilting of the crucible is omitted. It is also possible to continue refining continuously.
  • the power supply is stopped at the time of tapping, the surface of the molten metal is covered with the oxide slag.
  • the slag layer is broken and a current-carrying part is formed by the raw material, so that current can be continuously supplied.
  • the twin torch plasma is composed of at least one pair of anode and cathode electrodes, so that the crucible does not need to be conductive.
  • Each torch is inserted from the top of the melting furnace chamber into the melting crucible with the tip of the torch inserted into the melting crucible so that the melting atmosphere is not impaired, the insertion angle is variable, and the vertical position can be adjusted. Have been.
  • the selection range of the voltage, current and input of the plasma torch needs to be changed according to the melting amount per batch and melting time. Generally, it is necessary to increase the plasma current and output as the melting time increases and the melting time decreases. For example, when dissolving 50 kg of scrap per batch, 150 to 300 kW is appropriate. When dissolving 200 kg of scrap, 400 to 600 kW is appropriate.
  • melting by a tungsten arc melting furnace or a transition type plasma arc melting furnace is usually performed by a skull melting method using a copper water-cooled crucible in order to make a melting raw material directly opposite an arc torch.
  • a shell (skull) of a solidified layer is formed by the raw material itself on the inner surface of the water-cooled crucible. The raw material fed into the side is dissolved. If a part of the water-cooled crucible is insulated with refractory, etc., the molten pool will be wide and deep. For this reason, the molten metal temperature can be easily raised. Therefore, convection in the molten metal of the rare-earth magnet scrap or in the crucible residue having a high oxygen concentration is promoted, and the oxides are easily floated. Can be promoted.
  • This method employs a different crucible structure from the second method.
  • a structure in which the molten metal holding portion of the crucible is covered with a refractory material to form a heat insulating structure, and a structure in which the refractory material is locally covered with a metal electrode (first electrode) is selected.
  • the refractory surface is locally covered with a metal electrode in order to secure the power supply.
  • a plate electrode for this coating.
  • a plate-shaped metal electrode if one or more holes are provided at the bottom of the crucible, the temperature of the molten metal rises, and after sufficient separation of oxygen, the metal electrodes on and around the holes become It is possible to extract the molten metal, that is, to tap the molten metal by utilizing the fact that the molten metal disappears.
  • the timing of tapping can be controlled by controlling the heat input from the tungsten arc or transitional plasma arc during melting, or by selecting the material and thickness of the metal electrode described later. Can also be adjusted.
  • an iron electrode can be used as the material of the metal electrode.
  • an electrode made of industrial pure iron an electrode made of a high melting point metal such as niobium, molybdenum, tantalum, or an alloy thereof can be used.
  • the heat input from the tungsten arc or the transition type plasma arc is controlled so that the temperature of the molten metal pool does not become too high in the same way as preventing the incorporation of aluminum when using an alumina refractory. By doing so, the incorporation of the metal elements constituting these electrodes into the substance to be dissolved can be suppressed to a level that is not problematic.
  • the primary molten alloy according to the present invention will be described. Since this is melted as an ingot of 1 to 50 kg that can be directly charged into the secondary melting furnace, it will be referred to as “primary ingot” below.
  • the primary ingot of the present invention has a significantly lower oxygen concentration than the scrap state, and is significantly lower than the conventional vacuum-melted primary ingot.
  • the composition of this primary ingot is analyzed, combined with the virgin raw material, and the composition is determined so that the desired composition is obtained. Secondary melting and fabrication by the method described in (1) above to obtain a magnet alloy.
  • the amount of oxygen in the metal is reduced by the primary melting, when the secondary melting is performed using a vacuum high-frequency melting furnace, the slag-like metal content due to the unseparated oxide remaining in the metal decreases. It is possible to improve the yield.
  • the amount of primary ingot obtained from the rare earth magnet scrap must be determined in consideration of the following points. This is because scrap has a high carbon concentration due to the lubricant used during magnetic field press forming in the magnet manufacturing process, and decarburization is almost expected during primary melting. Therefore, the carbon content in the primary ingot is typically as high as 0.04% or more. Incidentally, the carbon content of the magnet alloy melted from the virgin material alone is usually less than 0.04%, and typically about 0.02%. If the amount of addition of the primary ingot is too large, the secondary dissolution ingot may be added. The carbon content of the magnet also increases, which adversely affects the properties of the magnet obtained from it.
  • the primary ingot obtained by the present method can be secondary-dissolved as 50% by weight or less, and the remainder can be a virgin raw material ratio.
  • the secondary ingot obtained by mixing and melting the primary ingot and the virgin raw material is used as the alloy for the magnet.
  • the primary ingot alone may be used as a magnet alloy, and the ratio of this alloy may be limited in the pulverization and mixing step in the subsequent magnet production.
  • the composition of the primary ingot of the present invention 15 to 40% of the rare earth element and Fe as the main component of the balance define the component range obtained by dissolving the most common grade of scrap. It was done.
  • Oxygen is mixed in as impurities in the manufacturing process of the rare-earth magnet, particularly in the pulverization process or the sintering process. However, since this reduction is an important achievement of the present invention, it is limited to 0.1% or less.
  • the components of the alloy for the magnet include Sm—Fe, Cu, Zr, and Nd (which may be partially replaced by Pr, Dy) of the Co-based magnet, _Fe—
  • B-based magnets such as B, A1, Co, Cu, and Nb, and these are used as components of magnet alloys regardless of the quantity.
  • Sm—Co magnets Co is 40 to 60%
  • Fe is 10 to 25%
  • Cu is 4 to: L0%
  • Zr is 4% or less.
  • B is 0.9 ⁇ : 1.2%
  • A1 is 0.1 ⁇ 1.5%.
  • a metal such as Fe is mixed from the metal electrode used in the third method, in addition to the trace elements from the various refractories described above, for example, A1 and the like.
  • This Fe is a necessary component of the magnet alloy.
  • a 1 is S m
  • a Co-based magnet is a harmful element for magnetic properties, while a Nd-Fe-B magnet is acceptable as a small alloy element, but too much is harmful to magnetic properties. Therefore, its amount is preferably less than 1%.
  • FIG. 1 is a sectional view showing one embodiment of a water-cooled copper crucible for carrying out the first and second methods of the present invention.
  • FIG. 2 is a sectional view showing one embodiment of a refractory crucible for carrying out the first method of the present invention.
  • FIG. 3 is a diagram showing an embodiment of the first melting apparatus of the present invention using a twin torch plasma arc melting furnace.
  • FIG. 4 is a view showing one embodiment of the melting apparatus according to the second and third aspects of the present invention using a transfer type plasma arc melting furnace.
  • FIG. 5 is a perspective view showing one embodiment of a water-cooled copper crucible provided with a current-carrying part for carrying out the second method of the present invention.
  • FIG. 6 is a drawing showing one embodiment of a refractory crucible for carrying out the third method of the present invention.
  • FIG. 7 is a drawing showing another embodiment of a refractory crucible for carrying out the third method of the present invention.
  • FIG. 8 is a drawing showing still another embodiment of the refractory crucible for carrying out the third method of the present invention. Description of embodiments of the invention
  • FIG. 1 shows a crucible having a water-cooled structure made entirely of copper for carrying out the method of the present invention.
  • 1 is a copper crucible
  • 2 is a refractory plate
  • 3 is a raw material
  • 4 is a cooling water inlet
  • 5 is a cooling water passage
  • 6 is a cooling water outlet.
  • the refractory plate 2 only at the bottom of the crucible 1 and leaving the side wall of the water-cooled copper crucible, the heat input by plasma and the insulation by the refractory plate 2 are balanced. However, the molten pool can be deepened. Also, if only the bottom is insulated, it is possible to reduce the amount of expensive refractory used, the shape of the refractory is simple, the durability is excellent, and the cost is excellent because it is inexpensive. Dissolution method.
  • FIG. 2 shows a refractory crucible for carrying out the method of the present invention.
  • a refractory crucible is placed in a metal container.
  • 7 is an alumina crucible
  • 9 is an iron container.
  • the gap between the crucible and the container is filled with alumina powder 8.
  • FIG. 3 shows an embodiment of a twin torch plasma melting furnace.
  • reference numeral 10 denotes a plasma torch, which generates plasma 11 between the anode torch 10a and the cathode torch 10Ob.
  • Fig. 4 shows the transfer type plasma arc melting furnace.
  • reference numeral 15 denotes a plasma torch, which generates a plasma arc between the torch and the raw material charged in the copper crucible 1.
  • the tungsten arc melting furnace has a structure provided with a tungsten electrode in place of the plasma torch 15 and generates an arc between the electrode and the raw material.
  • 16 is a raw material charging pipe.
  • FIG. 5 shows a crucible provided with a current-carrying part 17.
  • the current-carrying part 17 is formed by bending an iron plate or the like in accordance with the inner shape of the crucible so as to be in contact with the inner wall of the water-cooled copper crucible. Melting by this method ⁇ The following rare earth magnet scrap can be charged and melted inside the skull left after tapping.
  • a gap is formed between the crucibles due to the shrinkage of the remaining skull, which causes the conductivity to deteriorate and the crucible to be melted.
  • an energizing section 17 for ensuring conduction between the crucible on one side and the skull.
  • Fig. 5 three plasma transistors are used. 1 shows a crucible used in a plasma arc furnace with three conductors, and three conducting parts are provided so that the conducting parts are arranged between two torches, respectively.
  • the metal electrode 20 is, for example, a plate-like electrode covering the bottom of the crucible, and the crucible is vertically separated into a bottom 21 and a side wall 22.
  • the electrode 20 is sandwiched between the bottom 21 and the side wall 22 so as to ensure that power is supplied from the outer periphery of the electrode 20 to the power supply.
  • a crucible structure after the rare earth magnet scrap is melted, the crucible is tilted and heated.
  • a crucible structure in which a tap hole 25 is provided at the bottom 21 of the crucible may be employed.
  • Example 1 (Example of the first invention)
  • Analytical value of primary ingot Nd + Pr-25. 2 wt%, Dy-2.1 wt%, A1-0.34 wt%, B-1.00 wt%, O — 0.018 wt%, C-0.04 wt%, Fe remaining.
  • the melting amount of each knuckle is 1.5 kg, and the melting point of this alloy is 1200 to 125 ° C, so the melting temperature is more than 300 ° C higher than this.
  • the crucible 1 had an inner diameter of 170 mm and a depth of 70 mm, and an alumina sintered plate 2 having a thickness of 2 Omm was disposed at the bottom.
  • the primary dissolution yield was calculated by dividing the product weight by the charged raw material weight.
  • the melting time in this twin torch plasma arc melting furnace was 13 minutes, and the melting power of the primary ingot was 2.8 kWh Zkg. Since the crucible bottom is insulated, the melting time is short and the melting power is small.
  • the obtained alloy was used as a raw material and melted in an argon gas atmosphere using a vacuum high-frequency induction melting furnace.
  • the primary ingot is usually added to the virgin raw material to make the magnet alloy composition, but in order to investigate the yield, the entire amount was melted with the primary ingot alone.
  • Table 1 shows the dissolution yield of the obtained primary ingot, the dissolution yield of the secondary dissolution, and the average oxygen analysis value of the primary ingot.
  • Example 2 (Example of the second invention)
  • a scrap of the NdFeB magnet used in Example 1 was used as a raw material, and an alumina crucible (FIG. 2) was arranged. It was melted in a chi-plasma arc furnace to obtain a primary ingot.
  • Analytical value of primary ingot N d + P r — 25.0 wt%, D y — 2.2 wt%, A 1-0.38 wt%, B-0.99 wt%, O — 0.019 wt%, C-0. ⁇ 4 wt%, Fe remaining.
  • the dissolution amount of the batch was 1.5 kg, and the melting temperature was 1550 ° C.
  • the aluminum crucible 7 has an inner diameter of 170 mm, a depth of 70 mm, and a thickness of 30 mm.
  • This solution The solution time was 12 minutes and the dissolution power of the primary ingot was 2.6 kWhkg. As in Example 1, the dissolution time was short and the dissolution power was low. Table 1 shows the dissolution yield and average oxygen concentration at this time. These values were also the same as in Example 1, and an ingot with a high yield and a remarkably reduced oxygen concentration could be obtained.
  • Example 1 The NdFeB-based magnet scrap and virgin raw material used in Example 1 were melted using a 15 kW vacuum high-frequency induction melting furnace. The amount of dissolution was 5 kg, and the amount of scrap added to the virgin material was 50%. Table 1 shows the dissolution yield and average oxygen analysis value of the obtained primary ingot. The dissolution yield is assumed to be 95%, which is the average yield when dissolving the virgin raw material using only the virgin raw material, and the dissolving yield of only the scrap is adjusted to match the overall yield. The yield was calculated and the value was given.
  • Example 2 Using the scrap of the NdFeB-based magnet used in Example 1 as a raw material, 5 kg was melted using a 15 kW vacuum high-frequency induction melting furnace to obtain a primary ingot. Analytical value of primary ingot: Nd + Pr-25.0 wt%, Dy-2.3 wt%, A1-0.35 wt%, B-1.01 wt%, O -0.020 wt%, C-0.04 wt%, Fe remaining.
  • Example 1 As in Example 1, this primary ingot was melted again using a vacuum high-frequency induction melting furnace. As in Example 1, the dissolution yield and average oxygen analysis value were determined and are shown in Tables 1 and 2. Comparative Example 3
  • the scrap material of the NdFeB magnet used in Example 1 was used as a raw material in a 50 kW twin torch plasma arc melting furnace using a water-cooled copper crucible without any heat insulation. 5 kg was dissolved to obtain a primary ingot. Analytical value of primary ingot: Nd + Pr—28.0 wt%, Dy-2.4 wt%, A1-0.322 wt%, B-1.02 wt%, O — 0.42 wt%, C-0.04 wt%, Fe remaining.
  • This device can melt scrap with a melting point of 1200 to 125 ° C, but the melting temperature cannot be raised sufficiently because the crucible is not insulated. It stopped at 0 ° C.
  • the skull was also thick, and about half of the charged raw material remained in the crucible as a skull.
  • the melting time in this plasma arc melting furnace was 22 minutes, and the melting power for the primary ingot was 13 kWh / kg.
  • this primary ingot was melted using a vacuum high-frequency induction melting furnace.
  • the dissolution yield and the average oxygen analysis value were determined and are shown in Table 1.
  • the oxygen analysis value in the primary ingot is very high, and the deoxidizing effect is insufficient.
  • the scrap is melted in a plasma arc furnace equipped with a normal water-cooled crucible crucible, it is not insulated, and is not kept at a high temperature even if it is melted. It is clear that the oxygen concentration inside remains high. For this reason, the yield in the secondary melting in the high frequency induction furnace was low, and was about the same as when scrap was melted as it was. Ingot dissolution yield, oxygen analysis
  • the melting amount per batch is 1.5 kg and the melting point of this alloy is 1300 ° C Therefore, the melting temperature was set to 160 ° C., which is higher by 300 ° C. than this.
  • the crucible 1 had an inner volume of 11 O mm in diameter and a depth of 70 mm, and an alumina sintered plate 2 having a thickness of 20 mm was arranged on the bottom thereof.
  • the melting time in this arc melting furnace was 11 minutes, and the melting power of the primary ingot was 1.5 kWh / kg. Because the bottom is insulated, the melting time is short and the melting power is small.
  • the obtained alloy was used as a raw material and melted in an argon gas atmosphere using a vacuum high-frequency induction melting furnace.
  • the primary ingot is usually added to the virgin raw material to make the composition of the magnet alloy, but in order to investigate the yield, the entire amount was melted with the primary ingot alone.
  • Table 2 shows the dissolution yield of the obtained primary ingot, the dissolution yield of the secondary dissolution, and the average oxygen analysis value of the primary ingot.
  • Example 3 a conductive part made of a pure iron plate (thickness 1 mm x width 15 mm, 3 pieces) was provided in contact with the inner wall of the water-cooled copper crucible shown in Fig. 5
  • a primary ingot of the following analysis value was obtained.
  • the analysis value of the primary ingot was Nd + Pr-24.8 wt%, Dy-2.1 wt%, A1-0.35 wt%, B-0.98 wt%, O -0.018 wt%, C-0.04 wt%, Fe remaining.
  • Example 3 a magnetic alloy was melt-formed using this primary ingot.
  • the dissolution yield was determined, and the average oxygen analysis value of the primary ingot was measured.
  • Table 2 also in the plasma arc melting furnace, remarkably reducing the oxygen concentration and a high secondary melting yield were obtained as in Example 3 by melting the scrap at a high temperature.
  • the residue remaining in the crucible (Sm—31.6 wt%, Fe-4.6 wt%, Zr — 2.0 wt%, O—2.8 wt%, Co remaining) and a 30 kW tungsten-arc melting furnace with a water-cooled copper crucible ( Figure 1) insulated with a sintered aluminum plate at the bottom Metals could be recovered by melting in an argon gas atmosphere using a furnace.
  • the dissolution amount is 1.5 kg
  • the dissolution yield of the obtained primary ingot is 75%
  • the composition analysis value is Sm-15.0 wt%, Fe-28.0 wt% , Cu—4.6 wt%, Zr 2.5 wt%, O—0.021 wt%, Co remaining.
  • the high oxygen concentration residue in the high-frequency induction furnace crucible in the production of SmCo-based magnetic alloys is also significantly reduced in oxygen by high-temperature arc melting. Expensive metals such as Sm and Zr could be recovered in high yield as reusable metal.
  • Example 7 Example of the second invention
  • Example 3 To the scrap of the NdFeB magnet used in Example 3, 10% of a virgin material containing Nd metal, which is significantly oxidized, was added, and a primary ingot was obtained in the same manner as in Example 3. Was. The oxygen analysis value of this ingot was sufficiently reduced to no significant difference from Example 1.
  • Example 8 (Example of the first invention)
  • a scrap of 45 kg of the NdFeB magnet used in Example 1 was used as a raw material, the side was insulated with a sintered alumina cylinder 23, and only the bottom was a water-cooled copper plate 24.
  • melting was performed in an argon gas atmosphere to obtain a primary ingot.
  • Analytical value of primary ingot is Nd + Pr-25.8 wt%, Dy-2.3 wt%, A1-0.34 wt%, B-1.00 wt%, O -0.018 wt%, C-0.04 wt%, Fe remaining.
  • the dissolution temperature was set at 160, the same as in Example 3.
  • the crucible 1 was a sintered alumina cylinder 23 having an inner diameter of 32 O mm, a depth of 150 mm and a thickness of 30 mm, and a water-cooled copper plate 24 was disposed at the bottom.
  • Example 3 the magnetic alloy was melt-formed using this primary ingot. As shown in Table 2, in this method, too, by dissolving the scrap at a high temperature, the oxygen concentration was significantly reduced and a high secondary dissolution yield was obtained.
  • Example 6 after the NdFeB-based magnet scrap raw material was melted and discharged, before the molten metal was completely solidified, additional raw materials were added without breaking the argon gas atmosphere. Again, electricity was applied to dissolve. When the molten metal in the crucible became full, a part of the molten metal was poured out by tilting the crucible, and the raw material was added, so that it could be melted continuously. In addition, the metal solidified in the tap at the top of the crucible, and an abnormal arc flew in this part at the beginning of energization, so the solidified metal in this part was cut out slightly to make the tap. The same primary ingot as in Example 8 was obtained by dissolution by such a method.
  • Example 10 (Example of the third invention)
  • Scrap of NdFeB-based magnet used in Example 3 45 kg As a raw material, the sides were insulated with a sintered alumina cylinder, and the bottom was also insulated with a sintered alumina plate.
  • a 300 kW plasma arc melting furnace equipped with a crucible as shown in Fig. 6 in which a circular plate made of pure iron was installed as a current-carrying part melting was performed in an argon gas atmosphere, and the primary ingot was cooled. Obtained.
  • the dissolution temperature was set at 160 ° C., the same as in Example 1.
  • the crucible 1 is a sintered alumina cylinder 10 having an inner diameter of 32 O mm, a depth of 15 O mm and a thickness of 30 mm, and an outer diameter of 32 O mm and a thickness of 3 O mm at the bottom thereof.
  • a sintered alumina circular plate was placed, and a 0.5 mm pure iron circular plate was placed inside.
  • Example 1 1 (Example of the third invention)
  • the side part was insulated with a sintered alumina cylinder 22 and the tap hole 25 was left in the center of the bottom.
  • the crucible shown in FIG. 8 was provided, in which a doughnut-shaped sintered alumina plate 21 was insulated, and a pure iron circular plate 20 was installed as a conducting part inside the pure iron part as a conducting part. Melting was performed in an argon gas atmosphere using a kw plasma arc melting furnace. When melted, the center of the steel plate was broken, and the molten metal flowed to the bottom, and a primary ingot was obtained in the mold installed underneath.
  • the analysis value of the primary ingot was Nd + Pr-25.5 wt%, Dy-2.2 wt%, A1-0.35 wt%, B-1.01 wt%, O — 0.018 wt%, C— 0.04 wt%, Fe remaining.
  • the sintered aluminum plate at the bottom was a doughnut having an inner diameter of 10 O mm, an outer diameter of 320 mm, and a thickness of 30 mm under the same conditions as in Example 10. Dissolved. In this method, slag and some metal remained in the crucible, so that a 40 kg ingot with little slag entrainment was obtained.
  • Example 1 2 Example of the third invention
  • Example 10 After melting and tapping under the same conditions as in Example 10, the slag on the upper part of the solidified metal remaining in the crucible was partially scraped off, the lower metal layer was exposed and the energized part was secured. Was added, and the method of melting by re-energizing was repeated. At this time, there was also a charge with a hole in the center of the remaining solidified metal. In this case, iron foil or an iron plate was placed to close the hole and the raw material was charged. In this method, the same ingot as in Example 10 was obtained. Industrial applicability

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Abstract

L'invention concerne un procédé permettant d'augmenter le rendement obtenu dans un processus, qui consiste à séparer des métaux de déchets produits par un processus de production d'un aimant à base de terres rares. Les matériaux d'alliage pour aimant à base de terres rares sont raffinés par fusion, de façon à séparer positivement les oxydes, puis soumis à une seconde fusion au moyen d'un four de fusion à induction haute fréquence sous vide. Une partie ou la totalité des déchets (3) sont chargés dans un creuset (1) isolé (2) à refroidissement par eau, ou dans un creuset réfractaire (7, 21, 22), et soumis à une fusion au moyen de deux jets de plasma (10A, 10b) et à une fusion à l'électrode de tungstène ou à l'arc à migration.
PCT/JP1999/007264 1998-12-25 1999-12-24 Procede et appareil permettant de fondre des dechets magnetiques a base de terres rares et alliage primaire fondu de dechets magnetiques a base de terres rares WO2000039514A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2000591371A JP4263366B2 (ja) 1998-12-25 1999-12-24 希土類磁石スクラップの溶解方法及び溶解装置

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
JP10/370740 1998-12-25
JP37074098 1998-12-25
JP1680599 1999-01-26
JP11/16805 1999-01-26
US13715699P 1999-06-01 1999-06-01
US13715599P 1999-06-01 1999-06-01
US60/137,155 1999-06-01
US60/137,156 1999-06-01

Publications (2)

Publication Number Publication Date
WO2000039514A1 true WO2000039514A1 (fr) 2000-07-06
WO2000039514A9 WO2000039514A9 (fr) 2001-10-04

Family

ID=27456659

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP1999/007264 WO2000039514A1 (fr) 1998-12-25 1999-12-24 Procede et appareil permettant de fondre des dechets magnetiques a base de terres rares et alliage primaire fondu de dechets magnetiques a base de terres rares

Country Status (3)

Country Link
JP (1) JP4263366B2 (fr)
CN (1) CN100449240C (fr)
WO (1) WO2000039514A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102014206223A1 (de) 2014-04-01 2015-10-01 Fme Freiberger Metallrecycling Und Entwicklungsdienstleistungen Gmbh Verfahren zur Rückgewinnung Seltener Erden aus Seltene Erden-haltigen Zusammensetzungen
DE102014224015A1 (de) 2014-11-25 2016-05-25 Fme Freiberger Metallrecycling Und Entwicklungsdienstleistungen Gmbh Verfahren zur Rückgewinnung Seltener Erden aus Seltene Erden-haltigen Leuchtstoffen

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102492848B (zh) * 2011-12-22 2014-10-08 张森 一种用冷坩埚感应熔炼技术回收NdFeB废料的方法
CN104651612B (zh) * 2013-11-19 2017-06-20 荆门市格林美新材料有限公司 熔融稀土废料回收稀土的方法
CN108977674A (zh) * 2018-07-31 2018-12-11 邳州市尕星医药技术服务有限公司 一种从稀土电解废料中提取稀土氧化物的方法
CN108754163A (zh) * 2018-07-31 2018-11-06 邳州市尕星医药技术服务有限公司 一种从稀土废料中提取稀土金属的方法
KR102122428B1 (ko) * 2019-07-12 2020-06-19 주식회사 알인텍 주조 알니코 자석의 원재료 재생 방법 및 주조 알니코 자석의 제작 방법

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0533077A (ja) * 1991-07-26 1993-02-09 Tdk Corp Ｎｉ被覆希土類合金の再利用方法
WO1993020252A1 (fr) * 1992-03-31 1993-10-14 Mannesmann Ag Procede et dispositif pour traiter un materiau coulant
JPH06185879A (ja) * 1992-10-19 1994-07-08 Nippon Steel Corp 複式アーク炉設備の操業方法
JPH085247A (ja) * 1994-06-15 1996-01-12 Tsukishima Kikai Co Ltd プラズマ式溶融炉
JPH0831624A (ja) * 1994-07-15 1996-02-02 Sumikin Morikoopu Kk 希土類磁石スクラップの溶解方法
JPH0942850A (ja) * 1995-07-28 1997-02-14 Ishikawajima Harima Heavy Ind Co Ltd 直流アーク炉
JPH09243267A (ja) * 1996-03-11 1997-09-19 Takuma Co Ltd プラズマ溶融炉における溶融スラグの流動性低下防止方法
JPH09257221A (ja) * 1996-03-22 1997-09-30 Takuma Co Ltd プラズマ溶融炉及び被溶融物の溶融方法
JPH1047861A (ja) * 1996-08-06 1998-02-20 Nisshin Steel Co Ltd 電気炉

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0924326A (ja) * 1995-07-10 1997-01-28 Konica Corp 円筒状基材の塗布方法及び該装置

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0533077A (ja) * 1991-07-26 1993-02-09 Tdk Corp Ｎｉ被覆希土類合金の再利用方法
WO1993020252A1 (fr) * 1992-03-31 1993-10-14 Mannesmann Ag Procede et dispositif pour traiter un materiau coulant
JPH06185879A (ja) * 1992-10-19 1994-07-08 Nippon Steel Corp 複式アーク炉設備の操業方法
JPH085247A (ja) * 1994-06-15 1996-01-12 Tsukishima Kikai Co Ltd プラズマ式溶融炉
JPH0831624A (ja) * 1994-07-15 1996-02-02 Sumikin Morikoopu Kk 希土類磁石スクラップの溶解方法
JPH0942850A (ja) * 1995-07-28 1997-02-14 Ishikawajima Harima Heavy Ind Co Ltd 直流アーク炉
JPH09243267A (ja) * 1996-03-11 1997-09-19 Takuma Co Ltd プラズマ溶融炉における溶融スラグの流動性低下防止方法
JPH09257221A (ja) * 1996-03-22 1997-09-30 Takuma Co Ltd プラズマ溶融炉及び被溶融物の溶融方法
JPH1047861A (ja) * 1996-08-06 1998-02-20 Nisshin Steel Co Ltd 電気炉

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102014206223A1 (de) 2014-04-01 2015-10-01 Fme Freiberger Metallrecycling Und Entwicklungsdienstleistungen Gmbh Verfahren zur Rückgewinnung Seltener Erden aus Seltene Erden-haltigen Zusammensetzungen
DE102014224015A1 (de) 2014-11-25 2016-05-25 Fme Freiberger Metallrecycling Und Entwicklungsdienstleistungen Gmbh Verfahren zur Rückgewinnung Seltener Erden aus Seltene Erden-haltigen Leuchtstoffen
DE102014224015B4 (de) 2014-11-25 2019-07-04 Fme Freiberger Metallrecycling Und Entwicklungsdienstleistungen Gmbh Verfahren zur Rückgewinnung Seltener Erden aus Seltene Erden-haltigen Leuchtstoffen

Also Published As

Publication number Publication date
CN1335925A (zh) 2002-02-13
WO2000039514A9 (fr) 2001-10-04
CN100449240C (zh) 2009-01-07
JP4263366B2 (ja) 2009-05-13

Similar Documents

Publication Publication Date Title
US7381366B2 (en) Apparatus for the production or refining of metals, and related processes
EP0276544A1 (fr) Procédé de fusion par induction de métaux et d'alliages réactifs
JP5048222B2 (ja) 活性高融点金属合金の長尺鋳塊製造法
Bomberger et al. The melting of titanium
CN111593207B (zh) 一种低成本细晶CuCr触头材料的制备方法
CN101709393A (zh) 高性能低夹杂铜铬合金触头材料的制备方法
US20080298425A1 (en) Method and apparatus for melting metals using both alternating current and direct current
CN110578061A (zh) 一种高纯稀土金属的电子束熔炼连续铸锭方法
JPS6350434A (ja) 希土類金属および希土類含有合金の製造方法
US3469968A (en) Electroslag melting
WO2000039514A1 (fr) Procede et appareil permettant de fondre des dechets magnetiques a base de terres rares et alliage primaire fondu de dechets magnetiques a base de terres rares
CN212645338U (zh) 一种钛及钛合金的单或者多电极真空自耗电弧熔炼装置
CN212778615U (zh) 一种钛及钛合金的多电极真空非自耗电弧熔炼装置
TWI527942B (zh) Silicon electromagnetic casting device
JP4414861B2 (ja) 活性高融点金属含有合金の長尺鋳塊製造法
JP2011173172A (ja) 活性高融点金属合金の長尺鋳塊製造法
CN215713259U (zh) 一种制备4n级高纯铁的系统
JP7412197B2 (ja) Ｔｉ－Ａｌ系合金の製造方法
JP7379998B2 (ja) 誘導炉
JP4652537B2 (ja) チタン又はチタン合金製スクラップの溶解方法
WO2023026854A1 (fr) Four électrique et procédé de production de métal valorisable
JP2011230125A (ja) 長尺鋳塊の溶解製造方法
JPH0541715B2 (fr)
JPH11241127A (ja) 希土類金属を含有する合金スクラップの回収方法
RU2113520C1 (ru) Устройство для металлотермического получения редких и редкоземельных металлов, сплавов и лигатур на их основе

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 99816359.7

Country of ref document: CN

AK Designated states

Kind code of ref document: A1

Designated state(s): CN JP US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
ENP Entry into the national phase

Ref document number: 2000 591371

Country of ref document: JP

Kind code of ref document: A

AK Designated states

Kind code of ref document: C2

Designated state(s): CN JP US

AL Designated countries for regional patents

Kind code of ref document: C2

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE

COP Corrected version of pamphlet

Free format text: PAGES 5, 9, 10 AND 23, DESCRIPTION, REPLACED BY NEW PAGES 5, 9, 10 AND 23; PAGES 29 AND 30, CLAIMS, REPLACED BY NEW PAGES 29 AND 30; AFTER RECTIFICATION OF OBVIOUS ERRORS AS AUTHORIZED BY THE INTERNATIONAL SEARCHING AUTHORITY

122 Ep: pct application non-entry in european phase