JP6229846B2 - Separation and recovery method of rare earth elements and iron - Google Patents
Separation and recovery method of rare earth elements and iron Download PDFInfo
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- JP6229846B2 JP6229846B2 JP2014067735A JP2014067735A JP6229846B2 JP 6229846 B2 JP6229846 B2 JP 6229846B2 JP 2014067735 A JP2014067735 A JP 2014067735A JP 2014067735 A JP2014067735 A JP 2014067735A JP 6229846 B2 JP6229846 B2 JP 6229846B2
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims description 161
- 229910052761 rare earth metal Inorganic materials 0.000 title claims description 103
- 229910052742 iron Inorganic materials 0.000 title claims description 63
- 238000000034 method Methods 0.000 title claims description 42
- 238000011084 recovery Methods 0.000 title description 14
- 238000000926 separation method Methods 0.000 title description 13
- 239000002893 slag Substances 0.000 claims description 84
- 229910045601 alloy Inorganic materials 0.000 claims description 58
- 239000000956 alloy Substances 0.000 claims description 58
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 37
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 33
- 239000002994 raw material Substances 0.000 claims description 30
- 239000000203 mixture Substances 0.000 claims description 29
- 150000002910 rare earth metals Chemical class 0.000 claims description 26
- 239000000377 silicon dioxide Substances 0.000 claims description 25
- 239000012298 atmosphere Substances 0.000 claims description 19
- 238000002844 melting Methods 0.000 claims description 17
- 230000008018 melting Effects 0.000 claims description 17
- 229910052783 alkali metal Inorganic materials 0.000 claims description 14
- 150000001340 alkali metals Chemical class 0.000 claims description 14
- 229910052710 silicon Inorganic materials 0.000 claims description 11
- 239000010703 silicon Substances 0.000 claims description 8
- 229910052708 sodium Inorganic materials 0.000 claims description 7
- 229910000272 alkali metal oxide Inorganic materials 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 239000002253 acid Substances 0.000 claims description 3
- 229910017082 Fe-Si Inorganic materials 0.000 claims 7
- 229910017133 Fe—Si Inorganic materials 0.000 claims 7
- 229910000519 Ferrosilicon Inorganic materials 0.000 description 50
- 239000011734 sodium Substances 0.000 description 35
- 229910000905 alloy phase Inorganic materials 0.000 description 19
- 238000010438 heat treatment Methods 0.000 description 12
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 8
- 239000000843 powder Substances 0.000 description 8
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 7
- 229910002804 graphite Inorganic materials 0.000 description 7
- 239000010439 graphite Substances 0.000 description 7
- 229910052810 boron oxide Inorganic materials 0.000 description 5
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 description 5
- 239000000155 melt Substances 0.000 description 5
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 239000000523 sample Substances 0.000 description 4
- 229910000640 Fe alloy Inorganic materials 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 230000004907 flux Effects 0.000 description 3
- 238000004846 x-ray emission Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910017112 Fe—C Inorganic materials 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- 229910017493 Nd 2 O 3 Inorganic materials 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 239000012300 argon atmosphere Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 238000010587 phase diagram Methods 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910052723 transition metal Inorganic materials 0.000 description 2
- 150000003624 transition metals Chemical class 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910052582 BN Inorganic materials 0.000 description 1
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 description 1
- 229910004261 CaF 2 Inorganic materials 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 229910000881 Cu alloy Inorganic materials 0.000 description 1
- 229910017061 Fe Co Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 229910052771 Terbium Inorganic materials 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000994 depressogenic effect Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910001172 neodymium magnet Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000004445 quantitative analysis Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000003832 thermite Substances 0.000 description 1
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- 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
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Description
本発明は、希土類磁石のように希土類元素と鉄を含む原料から希土類元素と鉄を効率よく分離回収する方法に関する。 The present invention relates to a method for efficiently separating and recovering rare earth elements and iron from a raw material containing rare earth elements and iron such as rare earth magnets.
希土類元素は生産量が少ないので希土類元素を含有するスクラップなどから希土類元素を回収して再利用することが求められている。例えば、希土類磁石には希土類元素が多く含まれている。一方、希土類磁石には希土類と共に鉄が含まれており、このような希土類元素と鉄の合金から希土類元素を選択的に回収するには、共存する鉄を効率よく分離する必要がある。 Since rare earth elements are produced in small quantities, it is required to collect and reuse rare earth elements from scraps containing rare earth elements. For example, rare earth magnets contain a large amount of rare earth elements. On the other hand, rare earth magnets contain iron together with rare earths. To selectively recover rare earth elements from such rare earth element-iron alloys, it is necessary to efficiently separate the coexisting iron.
このような希土類磁石スクラップなどから希土類元素を回収する方法として、従来、以下のような方法が知られている。
（イ）希土類元素とＦｅを含む遷移金属とを含有する混合物原料を黒鉛坩堝内で不活性雰囲気下、１３５０℃〜１７００℃に加熱して溶融し、希土類元素を主成分とする酸化物相（Nd-Dy-Pr酸化物等）と遷移金属を含む金属相（Fe-Co合金等）とに分離させてこれらを回収する方法（特許文献１）。
（ロ）希土類元素と鉄を含む処理対象物を酸化し、さらに窒化ホウ素の存在下、１２００℃以上に加熱して希土類元素酸化物相（Nd-Dy-Pr酸化物等）と鉄系溶融相（Fe-M-O相、MはB、Cu、Ni）に分離する回収方法（特許文献２）。
（ハ）希土類元素と鉄族元素を含む処理対象物を、酸化処理した後に、または酸化処理せずに、炭素存在下で１１５０℃以上（例えば１４５０℃）に加熱して、希土類元素酸化物相（Nd-Dy-Pr酸化物等）と鉄合金相（Fe-C合金等）に分離する回収方法（特許文献３）
（ホ）希土類元素含有物質を酸化ホウ素フラックスの共存下で加熱溶融し、酸化ホウ素相と、その下方の希土類元素富化相とを形成し、１１５０〜１６００℃で１０〜３６０分保持した後に冷却してこれらを分離する希土類元素濃縮方法（特許文献４）。
（ヘ）鉄、銅と希土類元素を含有する物質を融点降下剤および酸化ホウ素の共存下で加熱溶融し、酸化ホウ素相（B2O3相）と、その下方の希土類元素富化相（Nd2O3- B2O3相）と、その下方の鉄富化相（Fe-C合金相）と、その下方の銅富化相（Cu合金相）とを形成し、１１５０〜１６００℃で１０〜３６０分保持した後に冷却してこれらを分離する希土類元素濃縮方法（特許文献５）。
（ニ）希土類−鉄−ボロン系磁石スクラップを酸化処理した後に該スクラップをアルミニウムまたはアルミニウム合金と混合し、該混合物に着火してテルミット反応によってフェロボロンを生成させ、スラグと分離して回収する方法（特許文献６）。
（ト）ネオジム磁石（Nd2Fe14B）スクラップをCaO−SiO2−Al2O3又はCaO−CaF2系スラグと混合し、不活性ガス雰囲気下で１５００℃に加熱して、磁石含有希土類元素（Nd、Pr、Tb）を上記スラグに移行させ、Ｆｅ富化合金から分離回収する方法（非特許文献１）。
Conventionally, the following methods are known as methods for recovering rare earth elements from such rare earth magnet scraps.
(A) A mixture raw material containing a rare earth element and a transition metal containing Fe is melted by heating at 1350 ° C. to 1700 ° C. in an inert atmosphere in a graphite crucible ( Nd-Dy-Pr oxide) and a metal phase containing a transition metal (Fe-Co alloy, etc.) and recovering them (Patent Document 1).
(B) Oxidize the object to be treated containing rare earth elements and iron, and further heat to 1200 ° C or higher in the presence of boron nitride, and rare earth element oxide phase (Nd-Dy-Pr oxide etc.) and iron-based molten phase (Fe-MO phase, M is B, Cu, Ni) A recovery method for separation (Patent Document 2).
(C) The object to be treated containing rare earth elements and iron group elements is heated to 1150 ° C. or higher (for example, 1450 ° C.) in the presence of carbon after oxidation treatment or without oxidation treatment, and the rare earth element oxide phase Recovery method for separation into (Nd-Dy-Pr oxide, etc.) and iron alloy phase (Fe-C alloy, etc.) (Patent Document 3)
(E) A rare earth element-containing substance is heated and melted in the presence of a boron oxide flux to form a boron oxide phase and a rare earth element-enriched phase below it, and cooled after being held at 1150 to 1600 ° C. for 10 to 360 minutes. Then, a rare earth element concentration method for separating them (Patent Document 4).
(F) A material containing iron, copper and a rare earth element is heated and melted in the presence of a melting point depressant and boron oxide, and a boron oxide phase (B 2 O 3 phase) and a rare earth element enriched phase (Nd) 2 O 3 -B 2 O 3 phase), a lower iron-enriched phase (Fe-C alloy phase), and a lower copper-enriched phase (Cu alloy phase) at 1150 to 1600 ° C. A rare earth element enrichment method (Patent Document 5) in which after cooling for 10 to 360 minutes, it is cooled and separated.
(D) A method in which rare earth-iron-boron magnet scrap is oxidized and then mixed with aluminum or an aluminum alloy, the mixture is ignited to produce ferroboron by a thermite reaction, and separated from slag and recovered ( Patent Document 6).
(G) Neodymium magnet (Nd 2 Fe 14 B) scrap is mixed with CaO-SiO 2 -Al 2 O 3 or CaO-CaF 2 slag, heated to 1500 ° C in an inert gas atmosphere, and magnet-containing rare earth A method in which elements (Nd, Pr, Tb) are transferred to the slag and separated and recovered from the Fe-enriched alloy (Non-Patent Document 1).
特許文献１、２の回収方法はフラックスを使用しないので、希土類元素の混合酸化物は固体であるため希土類元素と鉄との分離は不完全であり、鉄系合金と希土類元素の混合酸化物の分離作業に手間取る。特許文献２、３の回収方法は鉄と希土類元素を分離する前に、希土類元素を含む原料を酸化焙焼することが必要であるので、工程は複雑になる。また、特許文献４、５の希土類元素濃縮方法では酸化ホウ素系フラックスが蒸発する。さらに、希土類元素を含む原料を加熱溶融する温度は、特許文献１の実施例では１５５０℃（１８２３Ｋ）、特許文献２および特許文献３の実施例では１４５０℃（１７２３Ｋ）、非特許文献１の方法では１５００℃であり、何れも１４５０℃以上の高温であるので、エネルギーコストが大きい。 Since the collection methods of Patent Documents 1 and 2 do not use flux, the rare earth element mixed oxide is solid, so the separation of the rare earth element and iron is incomplete. It takes time for separation work. Since the recovery methods of Patent Documents 2 and 3 require oxidizing and roasting a raw material containing rare earth elements before separating iron and rare earth elements, the process becomes complicated. Further, in the rare earth element concentration methods of Patent Documents 4 and 5, the boron oxide-based flux evaporates. Furthermore, the temperature at which the raw material containing the rare earth element is heated and melted is 1550 ° C. (1823 K) in the example of Patent Document 1, 1450 ° C. (1723 K) in the examples of Patent Document 2 and Patent Document 3, and the method of Non-Patent Document 1 In this case, the temperature is 1500 ° C., and since both are high temperatures of 1450 ° C. or higher, the energy cost is high.
本発明の方法は、従来方法の上記問題を克服した回収方法であり、従来方法よりも溶融温度が低く、エネルギーコストを低減することができ、希土類元素を含むスラグ相と鉄を含む合金相が容易に分離し、効率よく希土類元素と鉄を分離して回収できる方法を提供する。 The method of the present invention is a recovery method that overcomes the above-mentioned problems of the conventional method. The melting temperature is lower than that of the conventional method, the energy cost can be reduced, and the slag phase containing rare earth elements and the alloy phase containing iron are present. Provided is a method for easily separating and efficiently separating and recovering rare earth elements and iron.
本発明は以下の構成を有する希土類元素と鉄の分離回収方法に関する。
〔１〕希土類元素と鉄を含む原料を、ＦｅリッチのＦｅ−Ｓｉ合金とアルカリ金属酸化物−シリカ系スラグの混合物に加え、不活性雰囲気下ないし還元雰囲気下で、１２５０℃〜１５５０℃に加熱溶融して希土類元素を上記スラグに移行させる一方、鉄をＦｅリッチのＦｅ−Ｓｉ溶融合金に移行させることによって希土類元素と鉄を分離する方法であって、上記Ｆｅ−Ｓｉ合金としてＦｅを６５〜９０wt％含むＦｅ−Ｓｉ合金を用い、上記アルカリ金属酸化物−シリカ系スラグとしてＮａ ２ Ｏを３５〜５０wt％含むＮａ ２ Ｏ−ＳｉＯ ２ 系スラグ、またはＣａＯ５wt％およびＮａ ２ Ｏ３３wt％およびＳｉＯ ２ ６２wt％を含むＣａＯ−Ｎａ ２ Ｏ−ＳｉＯ ２ 系スラグを用いることを特徴とする希土類元素と鉄の分離回収方法。
〔２〕原料に含まれる鉄が移行したＦｅ−Ｓｉ合金を回収し、このＦｅリッチのＦｅ−Ｓｉ合金にシリコンを添加してＦｅ−Ｓｉ比を調整し、これを原料溶融用のＦｅ−Ｓｉ合金として再利用する上記[１]に記載する希土類元素と鉄の分離回収方法。
〔３〕希土類元素を含むアルカリ金属酸化物−シリカ系スラグを回収し、該スラグを水や酸に溶解して希土類元素を浸出させ、残渣のシリカを回収し、該シリカにアルカリ金属酸化物を添加してアルカリ金属酸化物−シリカ比を調整し、これを原料溶融用のアルカリ金属酸化物−シリカ系スラグとして再利用する上記[１]または上記[２]の何れかに記載する希土類元素と鉄の分離回収方法。
〔４〕希土類元素と鉄を含む原料として希土類磁石のスクラップを用いる上記[１]〜上記[３]の何れかに記載する希土類元素と鉄の分離回収方法。
The present invention relates to a method for separating and recovering rare earth elements and iron having the following configuration.
[1] A raw material containing rare earth element and iron is added to a mixture of Fe-rich Fe-Si alloy and alkali metal oxide-silica slag, and heated to 1250 ° C to 1550 ° C in an inert atmosphere or a reducing atmosphere. while shifting the melted and rare earth elements in the slag, a method of separating rare earth elements and iron by shifting the iron Fe-Si molten alloy of Fe-rich, 65 and Fe as the Fe-Si alloy using Fe-Si alloy containing 90 wt%, the alkali metal oxides - Na 2 O-SiO 2 slag containing 35-50 wt% of Na 2 O as the silica-based slag or CaO5wt%, and Na 2 O33wt% and SiO 2 62 wt % Separation method of rare earth elements and iron, using CaO—Na 2 O—SiO 2 slag containing 1% .
[2] The Fe—Si alloy in which the iron contained in the raw material has been transferred is recovered, and silicon is added to the Fe-rich Fe—Si alloy to adjust the Fe—Si ratio. The method for separating and recovering rare earth elements and iron as described in [1] above, which is reused as an alloy.
[3] Collect alkali metal oxide-silica slag containing rare earth elements, dissolve the slag in water or acid to leach rare earth elements, collect residual silica, and add alkali metal oxide to the silica. The alkali metal oxide-silica ratio is added to adjust the rare earth element according to either [1] or [2] above, which is reused as an alkali metal oxide-silica-based slag for melting raw materials. Iron separation and recovery method.
[4] The method for separating and recovering rare earth elements and iron according to any one of [1] to [3] above , wherein rare earth magnet scrap is used as a raw material containing rare earth elements and iron.
〔具体的な説明〕
本発明の回収方法は、希土類元素と鉄を含む原料を、ＦｅリッチのＦｅ−Ｓｉ合金とアルカリ金属酸化物−シリカ系スラグの混合物に加え、不活性雰囲気下ないし還元雰囲気下で、１２５０℃〜１５５０℃に加熱溶融して希土類元素を上記スラグに移行させる一方、鉄をＦｅリッチのＦｅ−Ｓｉ溶融合金に移行させることによって希土類元素と鉄を分離する方法であって、上記Ｆｅ−Ｓｉ合金としてＦｅを６５〜９０wt％含むＦｅ−Ｓｉ合金を用い、上記アルカリ金属酸化物−シリカ系スラグとしてＮａ ２ Ｏを３５〜５０wt％含むＮａ ２ Ｏ−ＳｉＯ ２ 系スラグ、またはＣａＯ５wt％およびＮａ ２ Ｏ３３wt％およびＳｉＯ ２ ６２wt％を含むＣａＯ−Ｎａ ２ Ｏ−ＳｉＯ ２ 系スラグを用いることを特徴とする希土類元素と鉄の分離回収方法である。
本発明に係る分離回収方法の概略を図１に示す。
[Specific description]
In the recovery method of the present invention, a raw material containing a rare earth element and iron is added to a mixture of an Fe-rich Fe—Si alloy and an alkali metal oxide-silica slag, and the reaction is performed at 1250 ° C. to under an inert atmosphere or a reducing atmosphere. while allowing the heat fused to the rare earth element to 1550 ° C. migrated to the slag, a method of separating rare earth elements and iron by shifting the iron Fe-Si molten alloy of Fe-rich, as the Fe-Si alloy Fe—Si alloy containing 65 to 90 wt% Fe is used, and Na 2 O—SiO 2 slag containing 35 to 50 wt% Na 2 O as the alkali metal oxide-silica slag, or CaO 5 wt% and Na 2 O 33 wt% and separating and recovering method der rare earth elements and iron, which comprises using a CaO-Na 2 O-SiO 2 slag containing SiO 2 62 wt% The
An outline of the separation and recovery method according to the present invention is shown in FIG.
本発明の回収方法において、希土類元素と鉄を含む原料としては希土類磁石のスクラップを用いることができる。また、希土類元素は水素吸蔵合金、固体レーザー、各種の電子機器部品、燃料電池等にも含まれているので、これらのスクラップなども用いることができる。 In the recovery method of the present invention, a rare earth magnet scrap can be used as the raw material containing the rare earth element and iron. In addition, since rare earth elements are also contained in hydrogen storage alloys, solid lasers, various electronic device parts, fuel cells, etc., these scraps can also be used.
本発明の回収方法は、１２５０℃〜１５５０℃で溶融するＦｅリッチのＦｅ−Ｓｉ合金を用いる。なお、ＳｉリッチのＦｅ−Ｓｉ合金も上記温度下で溶融するが、合金中に取り込まれた希土類元素が合金中に残留して鉄とうまく分離できないので好ましくない。 The recovery method of the present invention uses an Fe-rich Fe—Si alloy that melts at 1250 ° C. to 1550 ° C. Si-rich Fe-Si alloys also melt at the above temperature, but this is not preferable because rare earth elements incorporated in the alloy remain in the alloy and cannot be separated well from iron.
図２のＦｅ−Ｓｉ系状態図に示すように、１２５０℃〜１５５０℃で溶融するＦｅリッチのＦｅ−Ｓｉ合金の組成は、例えば、Ｆｅ６５〜９０wt％の範囲である。原料に含まれる鉄をできるだけ多く受け入れるためには、Ｆｅ量が６５wt％に近いものが好ましく、Ｆｅ量が９０wt％に近づくと鉄を受け入れるキャパシティーが乏しくなる。 As shown in the Fe—Si system phase diagram of FIG. 2, the composition of the Fe-rich Fe—Si alloy that melts at 1250 ° C. to 1550 ° C. is, for example, in the range of Fe 65 to 90 wt%. In order to receive as much iron as possible in the raw material, it is preferable that the amount of Fe is close to 65 wt%. When the amount of Fe approaches 90 wt%, the capacity for receiving iron becomes poor.
溶融状態になるＦｅ−Ｓｉ合金のＦｅ/Ｓｉ比は加熱温度によって異なり、例えば、１３００℃では、Ｆｅ(75wt％)-Ｓｉ(25wt％)合金は溶融状態を保ち、加熱温度が高くなるとこれよりＦｅ量が多くても溶融状態を維持する。一方、Ｆｅ量が９０wt％以上のＦｅ−Ｓｉ合金は概ね１５５０℃において鉄を受け入れるキャパシティーが殆どないので、本発明のＦｅリッチＦｅ−Ｓｉ合金としては、Ｆｅ６５〜９０wt％のＦｅ−Ｓｉ合金が好ましい。 The Fe / Si ratio of the Fe-Si alloy in a molten state varies depending on the heating temperature. For example, at 1300 ° C., the Fe (75 wt%)-Si (25 wt%) alloy remains in a molten state, and the heating temperature increases. Even when the amount of Fe is large, the molten state is maintained. On the other hand, an Fe-Si alloy having an Fe amount of 90 wt% or more has almost no capacity for accepting iron at 1550 ° C. Therefore, the Fe-rich Fe-Si alloy of the present invention is Fe65-90 wt% Fe-Si alloy. preferable.
Ｆｅ(75wt％)-Ｓｉ(25wt％)合金は処理温度１３００℃において溶融状態であり、原料の希土類磁石中のＦｅがこのＦｅ−Ｓｉ合金へ溶け込んでＦｅ量が増しても、加熱温度を高めると溶融状態を保つので、鉄に対する合金のキャパシティーが充分大きく、原料の鉄を取込んで希土類元素と鉄の分離を促進することができる。 The Fe (75 wt%)-Si (25 wt%) alloy is in a molten state at a processing temperature of 1300 ° C. Even if Fe in the raw rare earth magnet melts into the Fe—Si alloy and the amount of Fe increases, the heating temperature is increased. Since the molten state is maintained, the capacity of the alloy with respect to iron is sufficiently large, and the separation of rare earth elements and iron can be promoted by incorporating the raw material iron.
このＦｅ−Ｓｉ合金は、粗粉砕した鉄とシリコンを黒鉛ルツボに入れ、不活性雰囲気下（例えば、アルゴン雰囲気）で１３００℃以上に加熱溶融して得ることができる。 This Fe—Si alloy can be obtained by putting coarsely pulverized iron and silicon into a graphite crucible and heating and melting them to 1300 ° C. or higher in an inert atmosphere (for example, argon atmosphere).
本発明の回収方法において、原料溶融用のアルカリ金属酸化物−シリカ系スラグは、例えば、Ｎａ2Ｏ−ＳｉＯ2系スラグ（Ｎａ2Ｏ：３５〜５０wt％）が好ましい。このスラグは、例えば、アルカリ金属源（炭酸ナトリウム等）とシリカの混合物を白金ルツボに入れ、大気下で１１００℃以上に加熱溶融することによって得ることができる。Ｎａ2Ｏ−ＳｉＯ2系スラグは融点と粘性が低く、本発明の回収方法における加熱温度で安定であり、数時間程度の加熱でもスラグ成分の蒸発がわずかである。 In the recovery method of the present invention, the alkali metal oxide-silica slag for melting the raw material is preferably, for example, Na 2 O—SiO 2 slag (Na 2 O: 35 to 50 wt%). This slag can be obtained, for example, by placing a mixture of an alkali metal source (sodium carbonate or the like) and silica in a platinum crucible and heating and melting to 1100 ° C. or higher in the atmosphere. Na 2 O—SiO 2 -based slag has a low melting point and viscosity, is stable at the heating temperature in the recovery method of the present invention, and the slag components are slightly evaporated even when heated for several hours.
Ｎａ２Ｏ−ＳｉＯ２系スラグとしては、具体的には、Ｎａ２Ｏ・２ＳｉＯ２スラグを用いることができる。また、カルシウムを含む三元系スラグ、例えば、ＣａＯ−Ｎａ２Ｏ−ＳｉＯ２ （ＣａＯ：５wt％、Ｎａ ２ Ｏ：３３wt％、ＳｉＯ ２ ：６２wt％）を用いることができる。ＣａＯ−Ｎａ２Ｏ−ＳｉＯ２スラグは、その粘性がＮａ２Ｏ・２ＳｉＯ２スラグに比べてさらに低く、熔融状態でＦｅ合金との分離がさらに良くなる。
Specifically, Na 2 O · 2SiO 2 slag can be used as the Na 2 O—SiO 2 slag. Further, a ternary slag containing calcium, for example, CaO—Na 2 O—SiO 2 (CaO: 5 wt%, Na 2 O: 33 wt %, SiO 2 : 62 wt%) can be used. The viscosity of CaO—Na 2 O—SiO 2 slag is lower than that of Na 2 O.2SiO 2 slag, and separation from the Fe alloy is further improved in a molten state.
本発明の回収方法は、希土類元素と鉄を含む原料を、ＦｅリッチのＦｅ−Ｓｉ合金とアルカリ金属酸化物−シリカ系スラグの混合物と共にルツボに入れ、この原料混合物を不活性雰囲気下ないし還元雰囲気下で、１２５０℃〜１５５０℃、好ましくは１２５０℃〜１４５０℃に加熱して溶融する。ルツボは黒鉛ルツボやセラミックス系ルツボ（アルミナ、マグネシア、ジルコニアなど）を使用することができる。原料混合物が溶融するまで加熱する。概ね５〜１５時間、好ましくは５時間程度でよい。 In the recovery method of the present invention, a raw material containing a rare earth element and iron is put in a crucible together with a mixture of an Fe-rich Fe-Si alloy and an alkali metal oxide-silica slag, and the raw material mixture is placed in an inert atmosphere or a reducing atmosphere. Below, it heats and melts at 1250 ° C to 1550 ° C, preferably 1250 ° C to 1450 ° C. As the crucible, a graphite crucible or a ceramic crucible (alumina, magnesia, zirconia, etc.) can be used. Heat until the raw material mixture melts. It may be about 5 to 15 hours, preferably about 5 hours.
加熱温度が１２５０℃未満になると、Ｆｅ−Ｓｉ合金の鉄のキャパシティーが小さくなり、原料に含まれる鉄がＦｅ−Ｓｉ合金相へ溶け込めなくなる。一方、加熱温度が１５５０℃を超えると、Ｆｅ−Ｓｉ合金を使用して加熱温度を下げる利点が失われる。低融点のＦｅ−Ｓｉ合金を使用することによって溶融温度を下げ、好ましくは鉄の融点（約１５３８℃）よりも低い１４５０℃以下の加熱温度で原料混合物を溶融させることによって、低コストで希土類元素と鉄を分離することができる。 When the heating temperature is less than 1250 ° C., the iron capacity of the Fe—Si alloy decreases, and the iron contained in the raw material cannot be dissolved into the Fe—Si alloy phase. On the other hand, when the heating temperature exceeds 1550 ° C., the advantage of using the Fe—Si alloy to lower the heating temperature is lost. By using a low melting point Fe-Si alloy, the melting temperature is lowered, and preferably the rare earth element is melted at a low cost by melting the raw material mixture at a heating temperature of 1450 ° C. or lower, which is lower than the melting point of iron (about 1538 ° C.). And iron can be separated.
原料混合物が不活性雰囲気下ないし還元雰囲気下で上記温度に加熱されて溶融すると、Ｆｅ−Ｓｉ溶融合金中のシリコンとアルカリ金属酸化物−シリカ系溶融スラグ中のＳｉＯ2の反応で所定の酸素ポテンシャルが維持され、その酸素ポテンシャルで希土類元素が酸化され、希土類元素酸化物がスラグ相に移行し、原料に含まれる鉄はＦｅ−Ｓｉ合金に移行する。Ｆｅ−Ｓｉ溶融合金とＮａ2Ｏ−ＳｉＯ2系スラグは比重差が大きいので、スラグ相と合金相は自然に分離する。 When the raw material mixture is heated and melted at the above temperature in an inert atmosphere or a reducing atmosphere, a predetermined oxygen potential is obtained by a reaction between silicon in the Fe-Si molten alloy and SiO 2 in the alkali metal oxide-silica-based molten slag. Is maintained, the rare earth element is oxidized by the oxygen potential, the rare earth element oxide is transferred to the slag phase, and the iron contained in the raw material is transferred to the Fe—Si alloy. Since the Fe—Si molten alloy and the Na 2 O—SiO 2 slag have a large specific gravity difference, the slag phase and the alloy phase are naturally separated.
分離したＦｅリッチのＦｅ−Ｓｉ合金を回収し、このＦｅリッチのＦｅ−Ｓｉ合金にシリコンを添加してＦｅ−Ｓｉ比を上記範囲（例えば、Fe75wt％−Si25wt％）に調整し、これを原料溶融用のＦｅ−Ｓｉ合金として再利用することができる。また、回収した鉄リッチのＦｅ−Ｓｉ合金はフェロシリコン製造などの原料として用いることができる。 The separated Fe-rich Fe-Si alloy is recovered, and silicon is added to the Fe-rich Fe-Si alloy to adjust the Fe-Si ratio to the above range (for example, Fe75wt% -Si25wt%). It can be reused as an Fe-Si alloy for melting. The recovered iron-rich Fe—Si alloy can be used as a raw material for ferrosilicon production.
分離した希土類元素を含むスラグを回収する。このスラグを水や酸に溶解して希土類元素を浸出させ、固液分離して希土類元素を含む溶液を得ることができる。 The separated slag containing rare earth elements is recovered. This slag can be dissolved in water or acid to leach rare earth elements, and solid-liquid separation can be performed to obtain a solution containing rare earth elements.
固液分離した残渣にはシリカが含まれているので、このシリカを回収してアルカリ金属酸化物を添加し、アルカリ金属酸化物−シリカ比を調整し、これを原料溶融用のアルカリ金属酸化物−シリカ系スラグとして再利用することができる。例えば、回収したシリカにＮａ2Ｏを添加してＮａ2Ｏ：３５〜５０wt％のＮａ2Ｏ−ＳｉＯ2系スラグを調製し、これを原料溶融用スラグとして再利用する。 Since silica is contained in the solid-liquid separated residue, this silica is recovered, an alkali metal oxide is added, and the alkali metal oxide-silica ratio is adjusted. -It can be reused as silica-based slag. For example, Na 2 O is added to the recovered silica to prepare Na 2 O: 35-50 wt% Na 2 O—SiO 2 slag, which is reused as raw material melting slag.
本発明の分離回収方法は、従来方法よりも低い温度で原料混合物を溶融させることができるのでエネルギーコストを低減することができる。また、溶融温度下でスラグが安定であり、スラグ成分が蒸発せずに希土類元素の溶解度が高い。さらに、希土類元素はスラグ相に移行し、鉄は合金相に移行し、この希土類元素を含むスラグ相と鉄を含む合金相の比重差が大きいので、スラグ相と合金相が自然に分離し、効率よく希土類元素と鉄を分離して回収することができる。具体的には、スラグ相に混入する鉄は１％未満なので希土類元素を選択的に回収することができる。 In the separation and recovery method of the present invention, the raw material mixture can be melted at a temperature lower than that of the conventional method, so that the energy cost can be reduced. Further, the slag is stable at the melting temperature, and the solubility of the rare earth element is high without evaporation of the slag component. Furthermore, the rare earth element moves to the slag phase, the iron moves to the alloy phase, and since the specific gravity difference between the slag phase containing the rare earth element and the alloy phase containing iron is large, the slag phase and the alloy phase naturally separate, Rare earth elements and iron can be separated and recovered efficiently. Specifically, since the iron mixed in the slag phase is less than 1%, the rare earth element can be selectively recovered.
本発明の実施例を以下に示す。Ｆｅ−Ｓｉ合金の組成は、ＥＰＭＡ（Electron Probe Micro Analyzer）とＸＲＦ法(X-ray Fluorescence Spectrometry)によって定性と定量分析を行った。スラグ組成は、ＸＲＦ法で定性し、化学分析とＩＣＰ−ＡＥＳ法（Inductively Coupled Plasma−Atomic Emission Spectrometry）によって定量分析を行った。 Examples of the present invention are shown below. The composition of the Fe—Si alloy was qualitatively and quantitatively analyzed by EPMA (Electron Probe Micro Analyzer) and XRF method (X-ray Fluorescence Spectrometry). The slag composition was qualitatively determined by the XRF method, and quantitative analysis was performed by chemical analysis and ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry).
〔実施例１〕
(１)Ｆｅ−Ｓｉ合金調製
鉄粉と粗粉砕したシリコンを、Ｆｅ７５wt％、Ｓｉ２５wt％になるように混合した後、黒鉛ルツボに装入し、電気炉内、アルゴン雰囲気下で、１４００℃にて１時間保持した。その後、試料を急冷しＦｅ−Ｓｉ合金を回収した。
(２)Ｎａ 2 Ｏ−ＳｉＯ 2 スラグ調製
Ｎａ2ＣＯ3とＳｉＯ2の混合物（Na2O:35wt％、SiO2:65wt％）を白金るつぼに装入し、電気炉を用い、大気中で１１００℃にて加熱溶融してＮａ2Ｏ−ＳｉＯ2スラグを調製した。１時間後に試料を取り出し、ルツボ内の溶融スラグを鉄板上に注ぎ回収した。
(３)希土類磁石の溶融処理
表１に示す希土類磁石（約６ｇ）を粉砕し、上記(１）で調製したＦｅ−Ｓｉ合金（約２４ｇ）と、上記(２)で調製したＮａ2Ｏ−ＳｉＯ2スラグ（約１５ｇ）と、上記希土類磁石粉砕物とを混合して黒鉛ルツボに装入し、アルゴンガスを３００mL/minで炉内導入しながら１３００℃で５時間保持した。処理後、坩堝を電気炉から取り出し、水急冷し、スラグ相（約１８ｇ）と合金相（約２８ｇ）を回収した。
(４)結果
処理前と処理後の合金相とスラグ相の組成をおのおの表２、表３に示す。表２、表３に示すように、原料の希土類磁石に含まれている希土類元素の約９０％はスラグへ移行した。このスラグの鉄品位は１％以下であり、鉄と希土類元素とが良好に分離された。
[Example 1]
(1) Preparation of Fe-Si alloy Iron powder and coarsely pulverized silicon were mixed so as to be Fe 75 wt% and Si 25 wt%, and then charged into a graphite crucible, in an electric furnace under an argon atmosphere, Hold at 1400 ° C. for 1 hour. Thereafter, the sample was rapidly cooled to recover the Fe—Si alloy.
(2) Na 2 O—SiO 2 slag preparation A mixture of Na 2 CO 3 and SiO 2 (Na 2 O: 35 wt%, SiO 2 : 65 wt%) was charged into a platinum crucible and used in an atmosphere using an electric furnace. Na 2 O—SiO 2 slag was prepared by heating and melting at 1100 ° C. One hour later, the sample was taken out, and the molten slag in the crucible was poured onto an iron plate and recovered.
(3) Rare earth magnet melting treatment The rare earth magnet shown in Table 1 (about 6 g) was pulverized, and the Fe—Si alloy (about 24 g) prepared in (1) above and the above (2) prepared. Na 2 O—SiO 2 slag (about 15 g) and the pulverized rare earth magnet were mixed and charged into a graphite crucible, and kept at 1300 ° C. for 5 hours while introducing argon gas into the furnace at 300 mL / min. After the treatment, the crucible was taken out of the electric furnace and quenched with water to recover a slag phase (about 18 g) and an alloy phase (about 28 g).
(4) Results Tables 2 and 3 show the compositions of the alloy phase and the slag phase before and after the treatment, respectively. As shown in Tables 2 and 3, about 90% of the rare earth elements contained in the raw rare earth magnets were transferred to slag. The iron grade of this slag was 1% or less, and iron and rare earth elements were well separated.
〔実施例２〕
Ｎａ2ＯとＳｉＯ2が同量のＮａ2Ｏ−ＳｉＯ2スラグ（Na2O:50wt％、SiO2:50wt％）を用い、それ以外は実施例１と同様の条件で希土類磁石粉末（約２.４ｇ）とＦｅ−Ｓｉ合金（約９.６ｇ）およびＮａ2Ｏ−ＳｉＯ2スラグ（約６ｇ）の混合物を加熱溶融し、スラグ相と合金相を回収した。原料の希土類磁石粉末を表４に示す。処理前と処理後の合金相とスラグ相の組成をおのおの表５、表６に示す。原料の希土類磁石に含まれている希土類元素の約１００％がスラグに移行し、このスラグに含まれる鉄の含有率は１％以下であった。
[Example 2]
Na 2 O and SiO 2 is the same amount of Na 2 O-SiO 2 slag (Na 2 O: 50wt%, SiO 2: 50wt%) using a rare earth magnet powder (approximately under the same conditions, otherwise as in Example 1 2.4 g), a Fe—Si alloy (about 9.6 g) and a Na 2 O—SiO 2 slag (about 6 g) were heated and melted to recover a slag phase and an alloy phase. Table 4 shows the raw rare earth magnet powder. Tables 5 and 6 show the compositions of the alloy phase and the slag phase before and after the treatment, respectively. About 100% of the rare earth element contained in the raw rare earth magnet was transferred to slag, and the content of iron contained in this slag was 1% or less.
〔実施例３〕
鉄粉とシリコン塊の混合物（Fe:75wt％、Si:25wt％、約１５ｇ）を粉砕し、黒鉛ルツボに装入して不活性雰囲気下で１３００℃にて６０分保持し、Ｆｅ−Ｓｉ溶融合金を形成した。次いで、Ｎａ2Ｏ−ＳｉＯ2スラグ（Na2O:35wt％、SiO2:65wt％、約３０ｇ）をＦｅ−Ｓｉ溶融合金上に装入して大気下で１３００℃にて３０分保持して溶解させた。その後、粗粉砕した希土類磁石粉末（約１５ｇ）をＦｅ−Ｓｉ合金・スラグ上に装入し、不活性雰囲気下で１３００℃にて５時間保持して溶融した後に、スラグ相と合金相を回収した。
原料の希土類磁石粉末を表７に示す。処理前と処理後の合金相とスラグ相の組成をおのおの表８、表９に示す。原料の希土類磁石に含まれている希土類元素の約１００％がスラグに移行し、このスラグ中の鉄は検出されなかった。
Example 3
A mixture of iron powder and silicon lump (Fe: 75wt%, Si: 25wt%, about 15g) was pulverized, charged into a graphite crucible and held at 1300 ° C for 60 minutes under an inert atmosphere, and Fe-Si melted An alloy was formed. Next, Na 2 O—SiO 2 slag (Na 2 O: 35 wt%, SiO 2 : 65 wt%, about 30 g) was charged onto the Fe—Si molten alloy and held at 1300 ° C. for 30 minutes in the atmosphere. Dissolved. After that, the coarsely pulverized rare earth magnet powder (about 15 g) was charged on the Fe-Si alloy / slag and kept at 1300 ° C. for 5 hours in an inert atmosphere to melt, and then the slag phase and alloy phase were recovered. did.
Table 7 shows the raw rare earth magnet powder. Tables 8 and 9 show the compositions of the alloy phase and the slag phase before and after the treatment, respectively. About 100% of the rare earth element contained in the raw rare earth magnet was transferred to slag, and iron in this slag was not detected.
〔実施例４〕
ＣａＯ−Ｎａ2Ｏ−ＳｉＯ2スラグ（ＣａＯ:５wt％、Ｎａ2Ｏ:３３wt％、ＳｉＯ2:６２wt％、約６ｇ）を用いた以外は実施例１と同様の条件で希土類磁石粉末（約２.４ｇ）とＦｅ−Ｓｉ合金（約９.６ｇ）の混合物を加熱溶融し、スラグ相と合金相を回収した。処理後の合金相の組成を表１０に示す。処理前と処理後のスラグ相の組成を表１１に示す。なお、希土類磁石粉末の組成は表４と同じ、処理前のＦｅ−Ｓｉ合金相の組成は表５と同じである。原料の希土類磁石に含まれている希土類元素の約５５％がスラグに移行し、残り約４５％は酸化物（Nd2O3-Dy2O3）を形成して合金相中に分散していた。処理後のスラグに含まれる鉄の含有率は１％以下であった。
Example 4
Rare earth magnet powder (about 2) under the same conditions as in Example 1 except that CaO—Na 2 O—SiO 2 slag (CaO: 5 wt%, Na 2 O: 33 wt%, SiO 2 : 62 wt%, about 6 g) was used. .4 g) and a Fe-Si alloy (about 9.6 g) were heated and melted to recover a slag phase and an alloy phase. Table 10 shows the composition of the alloy phase after the treatment. Table 11 shows the composition of the slag phase before and after the treatment. The composition of the rare earth magnet powder is the same as in Table 4, and the composition of the Fe—Si alloy phase before the treatment is the same as in Table 5. About 55% of the rare earth elements contained in the rare earth magnet of the raw material are transferred to slag, and the remaining about 45% form oxides (Nd 2 O 3 -Dy 2 O 3 ) and are dispersed in the alloy phase. It was. The content of iron contained in the slag after the treatment was 1% or less.
〔比較例１〕
鉄粉とシリコン塊の混合物（Fe:34wt％、Si:66wt％、約２４ｇ）を粉砕し、黒鉛ルツボに装入して不活性雰囲気下で１３００℃にて６０分保持した後、試料を急冷しＦｅ−Ｓｉ合金を回収した。このＦｅ−Ｓｉ合金を用いた以外は実施例１と同様の条件で希土類磁石粉末（約６ｇ）とＮａ2Ｏ−ＳｉＯ2スラグ（約１５ｇ）の混合物を加熱溶融し、スラグ相と合金相を回収した。処理前と処理後のスラグ相を表１２に示す。処理後の合金相の組成を表１３に示す。なお、希土類磁石粉末の組成は表４と同じ、処理前のスラグ相の組成は表５と同じである。原料の稀土類磁石に含まれている希土類元素の一部は金属として、他の一部は酸化物（Ｎｄ2Ｏ3とＤｙ2Ｏ3）の状態で合金中に残留し、スラグで回収できなかった。
[Comparative Example 1]
A mixture of iron powder and silicon lump (Fe: 34wt%, Si: 66wt%, about 24g) was pulverized, charged in a graphite crucible and held at 1300 ° C for 60 minutes under an inert atmosphere, and then the sample was rapidly cooled The Fe—Si alloy was recovered. A mixture of rare earth magnet powder (about 6 g) and Na 2 O—SiO 2 slag (about 15 g) was heated and melted under the same conditions as in Example 1 except that this Fe—Si alloy was used, and the slag phase and the alloy phase were separated. It was collected. Table 12 shows the slag phase before and after the treatment. Table 13 shows the composition of the alloy phase after the treatment. The composition of the rare earth magnet powder is the same as in Table 4, and the composition of the slag phase before the treatment is the same as in Table 5. Part of rare earth elements contained in rare earth magnets as raw materials is metal, and the other part remains in the state of oxides (Nd 2 O 3 and Dy 2 O 3 ) and can be recovered by slag. There wasn't.
希土類元素が濃縮されるスラグは、希土類元素を精製する原料として利用できる。処理後のＦｅ−Ｓｉ（フェロシリコン）合金は商品価値が高く再利用できる可能性は大きい。 Slag in which rare earth elements are concentrated can be used as a raw material for refining rare earth elements. The processed Fe—Si (ferrosilicon) alloy has a high commercial value and is highly likely to be reused.
Claims (4)
The method for separating and recovering rare earth elements and iron according to any one of claims 1 to 3 , wherein rare earth magnet scrap is used as a raw material containing rare earth elements and iron.
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