JP2014111802A - Method for recovering rare earth metals - Google Patents
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- JP2014111802A JP2014111802A JP2012266082A JP2012266082A JP2014111802A JP 2014111802 A JP2014111802 A JP 2014111802A JP 2012266082 A JP2012266082 A JP 2012266082A JP 2012266082 A JP2012266082 A JP 2012266082A JP 2014111802 A JP2014111802 A JP 2014111802A
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- 229910052761 rare earth metal Inorganic materials 0.000 title claims abstract description 83
- 150000002910 rare earth metals Chemical class 0.000 title claims abstract description 60
- 238000000034 method Methods 0.000 title claims abstract description 27
- -1 rare earth metal ions Chemical class 0.000 claims abstract description 32
- 150000003457 sulfones Chemical class 0.000 claims abstract description 22
- 238000005868 electrolysis reaction Methods 0.000 claims description 24
- 238000004070 electrodeposition Methods 0.000 claims description 12
- 229910052779 Neodymium Inorganic materials 0.000 claims description 11
- 229910052692 Dysprosium Inorganic materials 0.000 claims description 9
- 229910045601 alloy Inorganic materials 0.000 claims description 9
- 239000000956 alloy Substances 0.000 claims description 9
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 claims description 9
- KBQHZAAAGSGFKK-UHFFFAOYSA-N dysprosium atom Chemical compound [Dy] KBQHZAAAGSGFKK-UHFFFAOYSA-N 0.000 claims description 8
- 229910052751 metal Inorganic materials 0.000 claims description 8
- 239000002184 metal Substances 0.000 claims description 8
- 150000002739 metals Chemical class 0.000 claims description 7
- 238000011084 recovery Methods 0.000 claims description 7
- 125000004432 carbon atom Chemical group C* 0.000 claims description 5
- 229910021645 metal ion Inorganic materials 0.000 claims description 5
- 125000000217 alkyl group Chemical group 0.000 claims description 4
- 150000001875 compounds Chemical class 0.000 claims description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 239000000696 magnetic material Substances 0.000 claims description 3
- 229910001172 neodymium magnet Inorganic materials 0.000 abstract description 7
- 239000002659 electrodeposit Substances 0.000 abstract description 2
- 238000004519 manufacturing process Methods 0.000 abstract description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 20
- 239000008151 electrolyte solution Substances 0.000 description 16
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 14
- 229910052742 iron Inorganic materials 0.000 description 12
- 239000000243 solution Substances 0.000 description 9
- 150000002500 ions Chemical class 0.000 description 8
- 150000003839 salts Chemical class 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- HHVIBTZHLRERCL-UHFFFAOYSA-N sulfonyldimethane Chemical compound CS(C)(=O)=O HHVIBTZHLRERCL-UHFFFAOYSA-N 0.000 description 6
- 238000000151 deposition Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 4
- 229910052802 copper Inorganic materials 0.000 description 4
- 239000010949 copper Substances 0.000 description 4
- 230000008021 deposition Effects 0.000 description 4
- 239000003792 electrolyte Substances 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 3
- 229910052796 boron Inorganic materials 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 229910021397 glassy carbon Inorganic materials 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- HXJUTPCZVOIRIF-UHFFFAOYSA-N sulfolane Chemical compound O=S1(=O)CCCC1 HXJUTPCZVOIRIF-UHFFFAOYSA-N 0.000 description 3
- YBJCDTIWNDBNTM-UHFFFAOYSA-N 1-methylsulfonylethane Chemical compound CCS(C)(=O)=O YBJCDTIWNDBNTM-UHFFFAOYSA-N 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 150000002366 halogen compounds Chemical class 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 229910052702 rhenium Inorganic materials 0.000 description 2
- WUAPFZMCVAUBPE-UHFFFAOYSA-N rhenium atom Chemical compound [Re] WUAPFZMCVAUBPE-UHFFFAOYSA-N 0.000 description 2
- 229910052727 yttrium Inorganic materials 0.000 description 2
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 2
- PVSJGAIWOIMZFG-UHFFFAOYSA-N 1-ethylsulfonylbutane Chemical compound CCCCS(=O)(=O)CC PVSJGAIWOIMZFG-UHFFFAOYSA-N 0.000 description 1
- MBDUIEKYVPVZJH-UHFFFAOYSA-N 1-ethylsulfonylethane Chemical compound CCS(=O)(=O)CC MBDUIEKYVPVZJH-UHFFFAOYSA-N 0.000 description 1
- URDYJNJREUFXGD-UHFFFAOYSA-N 1-ethylsulfonylpropane Chemical compound CCCS(=O)(=O)CC URDYJNJREUFXGD-UHFFFAOYSA-N 0.000 description 1
- QRXUXNUNFHPWLQ-UHFFFAOYSA-N 1-methylsulfonylbutane Chemical compound CCCCS(C)(=O)=O QRXUXNUNFHPWLQ-UHFFFAOYSA-N 0.000 description 1
- GUBNFBYCBZWEES-UHFFFAOYSA-N 1-methylsulfonylpentane Chemical compound CCCCCS(C)(=O)=O GUBNFBYCBZWEES-UHFFFAOYSA-N 0.000 description 1
- QAPSIUMUNHNUPW-UHFFFAOYSA-N 1-methylsulfonylpropane Chemical compound CCCS(C)(=O)=O QAPSIUMUNHNUPW-UHFFFAOYSA-N 0.000 description 1
- JEXYCADTAFPULN-UHFFFAOYSA-N 1-propylsulfonylpropane Chemical compound CCCS(=O)(=O)CCC JEXYCADTAFPULN-UHFFFAOYSA-N 0.000 description 1
- VTWYQAQIXXAXOR-UHFFFAOYSA-N 2-methylsulfonylpropane Chemical compound CC(C)S(C)(=O)=O VTWYQAQIXXAXOR-UHFFFAOYSA-N 0.000 description 1
- 229910000497 Amalgam Inorganic materials 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 229910052693 Europium Inorganic materials 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910052689 Holmium Inorganic materials 0.000 description 1
- 229910052765 Lutetium Inorganic materials 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 229910052772 Samarium Inorganic materials 0.000 description 1
- 229910052771 Terbium Inorganic materials 0.000 description 1
- 229910052775 Thulium Inorganic materials 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 229910052769 Ytterbium 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
- 125000000484 butyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 239000002738 chelating agent Substances 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910000040 hydrogen fluoride Inorganic materials 0.000 description 1
- 239000012770 industrial material Substances 0.000 description 1
- 239000002608 ionic liquid Substances 0.000 description 1
- 229910052747 lanthanoid Inorganic materials 0.000 description 1
- 150000002602 lanthanoids Chemical class 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910001004 magnetic alloy Inorganic materials 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 238000001465 metallisation Methods 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 239000012982 microporous membrane Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- LNOPIUAQISRISI-UHFFFAOYSA-N n'-hydroxy-2-propan-2-ylsulfonylethanimidamide Chemical compound CC(C)S(=O)(=O)CC(N)=NO LNOPIUAQISRISI-UHFFFAOYSA-N 0.000 description 1
- ATINCSYRHURBSP-UHFFFAOYSA-K neodymium(iii) chloride Chemical compound Cl[Nd](Cl)Cl ATINCSYRHURBSP-UHFFFAOYSA-K 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 229910052755 nonmetal Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 125000001147 pentyl group Chemical group C(CCCC)* 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 229910001404 rare earth metal oxide Inorganic materials 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052706 scandium Inorganic materials 0.000 description 1
- SIXSYDAISGFNSX-UHFFFAOYSA-N scandium atom Chemical compound [Sc] SIXSYDAISGFNSX-UHFFFAOYSA-N 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 125000004434 sulfur atom Chemical group 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- XRADHEAKQRNYQQ-UHFFFAOYSA-K trifluoroneodymium Chemical compound F[Nd](F)F XRADHEAKQRNYQQ-UHFFFAOYSA-K 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Classifications
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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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- Electrolytic Production Of Metals (AREA)
Abstract
Description
本発明は、電析により希土類金属を回収する方法であり、特に電解に用いる溶媒として、ジアルキルスルホンを用いることを特徴とする希土類金属の回収方法に関する。 The present invention relates to a method for recovering rare earth metals by electrodeposition, and more particularly to a method for recovering rare earth metals, characterized in that dialkyl sulfone is used as a solvent used for electrolysis.
希土類金属は、発火合金、特殊レンズ、蛍光体、レーザー、永久磁石、ガラス等の着色剤、光磁気記録装置等、種々の工業材料に用いられているが、その資源は、比較的少なく、しかも、偏在しており、需要の増加により、価格の高騰が懸念される元素であり、近年そのリサイクルの研究が多くなされている。しかし、現状では、必ずしも合理的なプロセスが開発されているとは言い難い。例えば、1000℃以上の過酷な条件であったり、回収率が低く、結局高コストとなり、工業的実現性に問題があった。 Rare earth metals are used in various industrial materials such as ignition alloys, special lenses, phosphors, lasers, permanent magnets, colorants such as glass, magneto-optical recording devices, etc., but their resources are relatively small, and It is an ubiquitous element, and the price is likely to rise due to an increase in demand. In recent years, much research has been conducted on its recycling. However, at present, it is difficult to say that a rational process has been developed. For example, the conditions were severe conditions of 1000 ° C. or higher, the recovery rate was low, the cost was high, and there was a problem in industrial feasibility.
例えば、希土類合金をハライド化合物の溶融塩に浸漬し、該溶融塩に希土類元素のハロゲン化合物を溶出させ、蒸気として回収する方法（特許文献１）、希土類元素を含むレニウム溶液から、レニウムを回収した後、残渣液から、希土類金属の酸化物を得、これを溶融塩電解して希土類金属を回収する方法（特許文献２）。或いは溶融塩電解に際し、陽極と陰極との間を、希土類金属合金からなるバイポーラー電極型核膜で分画して、陽極室に希土類金属イオンを供給し、陰極に希土類金属又はその合金を電析させる方法（特許文献３）等が提案されているが、これらは溶融塩電解によるため、1000℃又はそれ以上の高温を必要とし、エネルギー的にも、また装置としても高価となる欠点があった。また、NbFeB磁石の削りくずや、スラグについて、酢酸やスルファミン酸を電解質液として用い、電解により鉄を分離した後、フッ化水素を加えて、フッ化ネオジムの沈殿を採取する方法（特許文献４）、本発明者らによるイットリウムやジスプロシウムに対してジメチルホルムアミド中での電析の報告（被特許文献１，２）等も知られているが、前者における電解は、鉄を除去するだけであり、希土類はフッ化物となるため、別途還元工程等を必要とする。また後者は、希土類金属イオンのジメチルホルムアミドへの溶解度が小さく、高電流密度での電析に難点があった。 For example, a method in which a rare earth alloy is immersed in a molten salt of a halide compound, a halogen compound of the rare earth element is eluted in the molten salt and recovered as a vapor (Patent Document 1), and rhenium is recovered from a rhenium solution containing the rare earth element Thereafter, a rare earth metal oxide is obtained from the residual liquid, and this is subjected to molten salt electrolysis to recover the rare earth metal (Patent Document 2). Alternatively, in molten salt electrolysis, the anode and cathode are separated by a bipolar electrode type nuclear film made of a rare earth metal alloy, rare earth metal ions are supplied to the anode chamber, and rare earth metal or its alloy is supplied to the cathode. However, since these methods are based on molten salt electrolysis, they require a high temperature of 1000 ° C. or higher, which is expensive in terms of energy and equipment. It was. Further, for NbFeB magnet shavings and slag, acetic acid or sulfamic acid is used as an electrolyte solution, iron is separated by electrolysis, hydrogen fluoride is added, and neodymium fluoride precipitate is collected (Patent Document 4) ), Reports of electrodeposition in dimethylformamide against yttrium and dysprosium by the present inventors (Patent Documents 1 and 2) are also known, but the electrolysis in the former only removes iron. Since rare earths become fluoride, a separate reduction step is required. In the latter, the solubility of rare earth metal ions in dimethylformamide is small, and there is a difficulty in electrodeposition at a high current density.
そこで本発明は、より効率よく、工業化に耐え得る希土類金属の回収方法を検討することを目的とするものである。 Accordingly, the present invention aims to study a method for recovering rare earth metals that can withstand industrialization more efficiently.
本発明は、上記理由に鑑み、より低コスト、具体的には、より低温（30℃〜130℃程度）で、且つ低設備コストによる希土類金属の回収方法の開発を目指し、電析法に注目し、希土類、中でもネオジム（Nd）やジスプロシウム（Dy）の新規回収方法の発明に至った。 In view of the above reasons, the present invention aims to develop a method for recovering rare earth metals at a lower cost, specifically, at a lower temperature (about 30 ° C. to 130 ° C.) and at a lower equipment cost. The present invention has led to the invention of a novel method for recovering rare earths, especially neodymium (Nd) and dysprosium (Dy).
本願において、上記課題を解決するための、請求項１に記載の発明は、電解槽において、少なくとも希土類金属イオンが溶存するジアルキルスルホンの溶液を電解処理して、陰極表面に希土類金属を電析することを特徴とする希土類金属の回収方法である。 In the present application, the invention according to claim 1 for solving the above-mentioned problem is to electrolyze a dialkyl sulfone solution in which at least rare earth metal ions are dissolved in an electrolytic cell, and to deposit the rare earth metal on the cathode surface. This is a method for recovering a rare earth metal.
また、請求項２に記載の発明は、前記ジアルキルスルホンが次式（１）で表わされる化合物であることを特徴とする希土類金属の回収方法である。 The invention according to claim 2 is a method for recovering a rare earth metal, wherein the dialkyl sulfone is a compound represented by the following formula (1).
また、請求項３に係る発明は、前記ジアルキルスルホン中に溶存する金属イオンは、希土類金属以外に他の金属例えば鉄イオンやホウ素イオン等を共存していてもよく、かかる場合には電析時の電位及び陰極過電圧の相違による電解等の電流値の変化に基づき、希土類金属の陰極への電析の初期又は終期を定めることを特徴とする発明である。 In the invention according to claim 3, the metal ions dissolved in the dialkyl sulfone may coexist with other metals such as iron ions and boron ions in addition to the rare earth metals. The initial or final stage of electrodeposition of the rare earth metal on the cathode is determined based on the change in the current value of electrolysis or the like due to the difference in potential and cathode overvoltage.
本願の請求項４に係る発明は、対象とする希土類金属として、ネオジムであることを特定した発明である。 The invention according to claim 4 of the present application is an invention that specifies neodymium as the target rare earth metal.
本願の請求項５に係る発明は、対象とする希土類金属として、ジスプロシウムを特定した発明である。 The invention according to claim 5 of the present application is an invention in which dysprosium is specified as a target rare earth metal.
更に本願の請求項６に係る発明は、陽極として、希土類金属、特に粗希土類金属又は希土類合金を用い、該陽極から、電解液であるジアルキルスルホン溶液中に少なくとも希土類金属イオンを供給しつつ電解を行うことを特徴とする発明である。 Furthermore, the invention according to claim 6 of the present application uses a rare earth metal, particularly a crude rare earth metal or a rare earth alloy as an anode, and performs electrolysis while supplying at least rare earth metal ions from the anode into a dialkyl sulfone solution as an electrolytic solution. This invention is characterized by being performed.
また更に、本願の請求項７に係る発明は、前記陽極としてネオジム磁性体、例えば使用済みのネオジム磁石、ネオジム磁石を製造する時に生ずる削りくず等の廃棄磁性体を用いることを特徴とする発明である。 Furthermore, the invention according to claim 7 of the present application is an invention characterized in that a neodymium magnetic material, for example, a used neodymium magnet, a waste magnetic material such as shavings generated when manufacturing a neodymium magnet is used as the anode. is there.
本発明は、少なくとも希土類金属イオンを溶存するジアルキルスルホン溶液を電解液として用い、電析により陰極表面上に希土類金属を析出させて回収することにより、比較的低温（30℃〜130℃程度）で、希土類金属を回収することができる。このため、エネルギー的にも、装置的にもきわめて低コストを実現し得るのである。 The present invention uses a dialkyl sulfone solution in which at least a rare earth metal ion is dissolved as an electrolytic solution, and deposits and collects a rare earth metal on the cathode surface by electrodeposition, so that it can be recovered at a relatively low temperature (about 30 ° C. to 130 ° C.). The rare earth metal can be recovered. For this reason, extremely low cost can be realized in terms of energy and apparatus.
本発明の最大の特徴は、電解質液として、ジアルキルスルホンを用いることにある。かくして、希土類金属の比較的高い溶解度が得られ、このため電解電流を大きくすることが可能となり工業的レベルの希土類回収が可能となるのである。 The greatest feature of the present invention is that dialkyl sulfone is used as the electrolyte solution. Thus, a relatively high solubility of the rare earth metal is obtained, so that the electrolysis current can be increased and industrial level rare earth recovery is possible.
本発明の今一つの特徴は、電解質溶液中での電解であり、希土類金属の標準還元電位（V）が、表１に示す如く、Fe（−0.440V）やAl（−1.676V）等に較べて非常に低いという特性を利用する点である。 Another feature of the present invention is the electrolysis in the electrolyte solution, and the standard reduction potential (V) of the rare earth metal is higher than that of Fe (−0.440 V), Al (−1.676 V), etc. as shown in Table 1. The advantage is that it is very low.
本発明の最大の特徴は、電解液にある。すなわち、イオン液体等の高価な電解質溶液を用いるのではなく、ジアルキルスルホンを用いる点にある。すなわち、驚くべきことに希土類金属イオンが、例えばアルミニウム等の他の土類金属とは異なり、ジアルキルスルホン溶液のみを主たる電解液として用いることができるという点である。 The greatest feature of the present invention is the electrolytic solution. That is, instead of using an expensive electrolyte solution such as an ionic liquid, dialkyl sulfone is used. That is, surprisingly, rare earth metal ions, unlike other earth metals such as aluminum, can use only dialkyl sulfone solution as the main electrolyte.
本発明に用いられるジアルキルスルホンは、次の式（１）に示される。 The dialkyl sulfone used in the present invention is represented by the following formula (1).
上記式（１）において、Ｒ１，Ｒ２は、同一又は異なる炭素数よりなるアルキル基であり、Ｒ１，Ｒ２の炭素数の合計は、２〜６である。またＲ１，Ｒ２の一方端は硫黄原子に結合しているが、他は、場合によっては両者が結合し、環状を形成していてもよい。アルキルの具体例としては、メチル基、エチル基、プロプル基、ブチル基、ペンチル基であり、これらは分枝を有していてもよいし、また２重結合が存在していてもよい。但し、アルキル基が大きくなると、金属イオンの溶解液が低下するため、本発明にあっては、Ｒ１，Ｒ２の合計の炭素数は６程度までが好ましい。従って、本発明のジアルキルスルホン化合物としては、ジメチルスルホン、メチルエチルスルホン、メチルプロピルスルホン、メチルブチルスルホン、メチルペンチルスルホン、ジエチルスルホン、エチルプロピルスルホン、エチルブチルスルホン、ジプロピルスルホン、スルホラン、メチルアクリルスルホン、メチルアリルスルホン等であり、例えばジメチルスルホンやスルホラン等の如く融点が常温以上の場合は、それらが溶解する以上の温度、例えば30℃〜130℃程度の温度で電解を行えばよい。
In the above formula (1), R 1, R 2 are identical or different alkyl radicals comprising from carbon atoms, the total number of carbon atoms of R 1, R 2 is 2-6. In addition, one end of R 1 and R 2 is bonded to a sulfur atom, but in other cases, both may be bonded to form a ring. Specific examples of alkyl include a methyl group, an ethyl group, a propylene group, a butyl group, and a pentyl group, which may have a branch or may have a double bond. However, since the dissolved solution of metal ions decreases as the alkyl group increases, the total number of carbon atoms of R 1 and R 2 is preferably up to about 6 in the present invention. Accordingly, the dialkyl sulfone compounds of the present invention include dimethyl sulfone, methyl ethyl sulfone, methyl propyl sulfone, methyl butyl sulfone, methyl pentyl sulfone, diethyl sulfone, ethyl propyl sulfone, ethyl butyl sulfone, dipropyl sulfone, sulfolane, methyl acrylic sulfone. When the melting point is not lower than room temperature, such as dimethyl sulfone or sulfolane, electrolysis may be performed at a temperature higher than the temperature at which they dissolve, for example, about 30 ° C. to 130 ° C.
また、該ジアルキルスルホン中に溶存させる少なくとも希土類金属イオンとしては、特に限定されず、イットリウム（Y）、スカンジウム（Sc）及びランタノイド（La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu）の17元素のうち、いずれであってもよいし、またこれらの混合物であってもよい。特にこれらの金属に例えば鉄（Fe）やホウ素（B）等の他元素である金属又は非金属イオンが混在していてもよい。 The at least rare earth metal ions dissolved in the dialkyl sulfone are not particularly limited, and include yttrium (Y), scandium (Sc), and lanthanoids (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb). , Dy, Ho, Er, Tm, Yb, Lu), and any of these, or a mixture thereof. In particular, these metals may be mixed with other elements such as iron (Fe) and boron (B), or metals or non-metal ions.
本発明にあっては、これらの希土類金属は、一般に前記ジアルキルスルホンに可溶な塩としてジアルキルスルホンに溶解して用いる。一般にはハロゲン化合物、特に塩化物等である。 In the present invention, these rare earth metals are generally used by dissolving in dialkyl sulfone as a salt soluble in the dialkyl sulfone. Generally, it is a halogen compound, especially chloride.
更に好ましい本発明の態様は、陽極として希土類金属を含む合金、例えばネオジム磁性合金或いはその他の元素を含む伝導性粗希土類物質を用い、電解中に希土類金属イオンを電解液中に供給しつつ電解を行い陰極表面に希土類金属を電析する方法である。 In a more preferred embodiment of the present invention, an alloy containing a rare earth metal as an anode, for example, a neodymium magnetic alloy or a conductive crude rare earth material containing other elements, is used for electrolysis while supplying rare earth metal ions to the electrolyte during electrolysis. This is a method of depositing rare earth metal on the cathode surface.
かかる手段として好ましい材料は、使用済みのネオジム磁石であり、これらから、ネオジム又はジスプロシウムを回収する方法である。勿論、ネオジムは又はジスプロシウムの回収はネオジム磁石のみからの回収ではなく、ジアルキルスルホン溶液に共存しているこれら金属イオンについても同様に回収することは可能である。 A preferable material as such means is a used neodymium magnet, from which neodymium or dysprosium is recovered. Of course, the recovery of neodymium or dysprosium is not only recovery from a neodymium magnet, but it is also possible to recover these metal ions coexisting in a dialkyl sulfone solution.
本発明における電解は、一般に行われる電解槽やメッキ槽を何等制限されることなく使用することができる。本発明の原理は、図１に示すとおり、陽極と陰極を設けた電解槽にジアルキルスルホン溶液を電解質液として満たし、直流又はパルス直流電流を印加する。この場合ジアルキルスルホン中に希土類金属イオンを溶存させておき、該希土類金属イオンの電析に必要な電圧すなわち、該希土類金属の還元電位や陰極の過電圧以上の電位を印加し、陰極上に該希土類金属を析出させる。一般にジアルキルスルホンは、希土類金属イオンは溶解するが、電解に際しては0.05モル乃至飽和濃度で溶存させるのがよい。 The electrolysis in the present invention can use an electrolytic cell and a plating cell that are generally used without any limitation. The principle of the present invention is that, as shown in FIG. 1, an electrolytic cell provided with an anode and a cathode is filled with a dialkyl sulfone solution as an electrolyte solution and a direct current or a pulsed direct current is applied. In this case, a rare earth metal ion is dissolved in the dialkyl sulfone, and a voltage necessary for electrodeposition of the rare earth metal ion, that is, a potential higher than the reduction potential of the rare earth metal or the cathode overvoltage is applied, and the rare earth metal ion is applied to the cathode. Deposit metal. In general, dialkyl sulfone dissolves rare earth metal ions, but it is preferable to dissolve at 0.05 mol to saturated concentration during electrolysis.
また、希土類金属以外の金属、例えば鉄やホウ素等が共存している場合は、それらのイオンとの電解電位（陰極での還元電位）や過電圧の差によってイオンの析出が異なるので、例えば電解槽を定電圧制御しておけば電流量が急激に変化する時点で析出状態が変わるので、あらかじめ目的とする希土類金属イオンの電解電圧をチェックしておき、それ以上の電圧を印加しておき電流量の変化で、希土類金属の析出における始期又は終期が判定し得るので、使用する陰極を取り替えるか、別の電解槽に移動させて電解を行えばよい。 In addition, when metals other than rare earth metals such as iron and boron coexist, the deposition of ions varies depending on the electrolytic potential (reduction potential at the cathode) and overvoltage with those ions. If the voltage is controlled at a constant voltage, the deposition state changes when the amount of current changes abruptly, so check the target electrolysis voltage of the rare earth metal ion in advance and apply a voltage higher than that. Thus, the start or end of the rare earth metal deposition can be determined. Therefore, the cathode to be used may be replaced or moved to another electrolytic cell for electrolysis.
図２は、ジアルキルスルホン中に陽極から希土類金属を供給しつつ電解を行う場合の模式図である。該図では、ジスプロシウムを含むネオジム磁石を陽極とし、陽極酸化によりジアルキルスルホン中に希土類金属イオンを供給しつつ電解を行う場合の例である。 FIG. 2 is a schematic diagram when electrolysis is performed while supplying a rare earth metal from an anode into a dialkyl sulfone. This figure shows an example in which electrolysis is performed with a neodymium magnet containing dysprosium as an anode and supplying rare earth metal ions into dialkyl sulfone by anodic oxidation.
この場合、図３に示す如く、例えば鉄イオンが共存すると、鉄は希土類金属例えばネオジムやジスプロシウムに比べ還元電位が貴であるため鉄イオンが先に析出する。 In this case, as shown in FIG. 3, for example, when iron ions coexist, iron has a reduction potential noble compared with rare earth metals such as neodymium and dysprosium, so iron ions are deposited first.
図３にあっては、陰極として銅を用い、ジアルキルスルホン電解液に鉄又はネオジムのイオンを0.1モル溶存させた場合の電流量の差（mA/cm２）を経時的に示した図である。このようにあらかじめ、目的とする希土類の析出電位を求めておけば、定電圧制御下に電流密度の変化によって、希土類析出の始期又は終期を知り、その時点で陰極を交換するなり別の電解槽に電解液を移して希土類金属の回収を行うことができるのである。 In FIG. 3, it is the figure which showed temporally the difference (mA / cm < 2 >) of the amount of electric current when copper is used as a cathode and 0.1 mol of iron or neodymium ions are dissolved in the dialkylsulfone electrolyte. . In this way, if the deposition potential of the target rare earth is obtained in advance, the start or end of the rare earth deposition is known by changing the current density under constant voltage control, and the cathode is replaced at that time. It is possible to recover the rare earth metal by transferring the electrolytic solution to.
なお、場合によっては、鉄イオン等の希土類金属以外のイオンと錯体を形成し、沈殿を生ずる化合物（キレート化剤）等を共存させておくことも好ましい。 In some cases, it is also preferable that a compound (chelating agent) or the like that forms a complex with an ion other than the rare earth metal such as an iron ion and causes precipitation is coexisted.
図４は、電解液を電解槽外に循環させ鉄イオン等の希土類金属イオン以外の溶存イオンとキレートを形成する化合物のカラムを通して、不純物である希土類以外のイオンを除去して電解槽に戻しつつ電解を行う方法であり、この方法も好ましい。この場合、好ましくは、陽極と陰極の間に隔膜を設け、陽極側の溶液を循環することによって不純物イオンを除去するのが好ましい。また隔膜としては半透膜、微多孔膜等であり、電解液に侵されない材質であればプラスチックや繊維織物等特に制限されない。 FIG. 4 shows that an ion other than the rare earth that is an impurity is removed and returned to the electrolytic cell through a column of a compound that chelates with dissolved ions other than rare earth metal ions such as iron ions by circulating the electrolytic solution outside the electrolytic cell. This is a method of performing electrolysis, and this method is also preferable. In this case, it is preferable to remove the impurity ions by providing a diaphragm between the anode and the cathode and circulating the solution on the anode side. The diaphragm is a semipermeable membrane, a microporous membrane or the like, and is not particularly limited as long as it is a material that is not affected by the electrolyte solution.
尚、陰極に用いられる材料としては、好ましくは目的とする希土類金属であるが、その他導電性材料、例えば銅、ニッケル、白金、炭素、グラッシーカーボン等、又は鉄とアマルガムを作らない水銀等も好適な材料である。 The material used for the cathode is preferably a target rare earth metal, but other conductive materials such as copper, nickel, platinum, carbon, glassy carbon, or mercury that does not form iron and amalgam are also suitable. Material.
以下に実施例を示す。 Examples are shown below.
実施例においては、図５に示す電解槽を用いた。図中、参照極は銀線、作用極は銅、対極はグラッシーカーボンを表す。
〔実験方法〕
In the examples, the electrolytic cell shown in FIG. 5 was used. In the figure, the reference electrode represents a silver wire, the working electrode represents copper, and the counter electrode represents glassy carbon.
〔experimental method〕
電析用電解液の溶媒には有機溶媒として、ジメチルスルホン(DMSO２,東京化成工業株式会社),スルホラン(キシダ株式会社),エチルメチルスルホン(東京化成工業株式会社), イソプロピルメチルスルホン(東京化成工業株式会社) , N,N-ジメチルホルムアミド(DMF, 和光純薬工業株式会社；比較例)を使用した。電解質塩には、無水の塩化ネオジム(NdCl３, 和光純薬工業株式会社：99.9 %)を使用した。窒素雰囲気下のグローブボックス中でNdCl３を0.25 g量りとり、上記のそれぞれの有機溶媒10 ml中に0.1 mol dm−３となるように溶解させたものを電析用電解液とした。電析実験にはビーカー型セルを用い、
試験極には銅板(0.5 cm×2.5 cm)を、対極にはグラシーカーボン板(2
cm×2.5 cm)、 参照極には銀線を使用した(図1参照)。電析には、ポテンショガルバノスタット(東陽テクニカ solartoron 1280C)を使用し定電位-3.5 V(vs. Ag)で1時間行った。電析出物の形態は、走査型電子顕微鏡(SEM, 株式会社キーエンスVE-9800)で観察した。析出物の定性は、 エネルギー分散型Ｘ線分析装置(EDX, エダックスジャパン株式会社)で行った。
As an organic solvent for the electrolyte solution for electrodeposition, dimethyl sulfone (DMSO 2 , Tokyo Chemical Industry Co., Ltd.), sulfolane (Kishida Co., Ltd.), ethyl methyl sulfone (Tokyo Chemical Industry Co., Ltd.), isopropyl methyl sulfone (Tokyo Chemical Industry Co., Ltd.) Kogyo Co., Ltd.), N, N-dimethylformamide (DMF, Wako Pure Chemical Industries, Ltd .; Comparative Example) was used. Anhydrous neodymium chloride (NdCl 3 , Wako Pure Chemical Industries, Ltd .: 99.9%) was used as the electrolyte salt. An electrolytic solution for electrodeposition was obtained by weighing 0.25 g of NdCl 3 in a glove box under a nitrogen atmosphere and dissolving it in 10 ml of each of the above organic solvents so as to be 0.1 mol dm −3 . A beaker cell was used for the electrodeposition experiment.
The test electrode is a copper plate (0.5 cm x 2.5 cm), and the counter electrode is a glassy carbon plate (2
cm × 2.5 cm), and a silver wire was used for the reference electrode (see Fig. 1). Electrodeposition was performed using a potentiogalvanostat (Toyo Technica solartoron 1280C) at a constant potential of -3.5 V (vs. Ag) for 1 hour. The morphology of the electrodeposits was observed with a scanning electron microscope (SEM, Keyence VE-9800). The qualitative properties of the precipitates were measured with an energy dispersive X-ray analyzer (EDX, EDX Japan Co., Ltd.).
結果は表２に示す。 The results are shown in Table 2.
上記（ａ）〜（ｄ）の電極結果のSEM写真を図６に示し、エネルギー分散型Ｘ線分析図を図７に示す。図６において、左から（ａ）、（ｂ）、（ｃ）、（ｄ）の結果を示す。
An SEM photograph of the electrode results (a) to (d) is shown in FIG. 6, and an energy dispersive X-ray analysis diagram is shown in FIG. In FIG. 6, the results of (a), (b), (c), and (d) are shown from the left.
Claims (7)
The method for recovering a rare earth metal according to claim 6, wherein the anode is a neodymium magnetic material.
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| KR20160116429A (en) | 2015-03-30 | 2016-10-10 | 충남대학교산학협력단 | Apparatus for recovering neodymium matal using electrowinning |
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| JPH02310390A (en) * | 1989-05-25 | 1990-12-26 | Ishihara Chem Co Ltd | Rare earth metal plating solution |
| JP2012087329A (en) * | 2010-10-15 | 2012-05-10 | Yokohama National Univ | Method for recovering iron group element and rare earth element using ionic liquid, and apparatus for recovering iron group element and rare earth element |
| JP2013204126A (en) * | 2012-03-29 | 2013-10-07 | Hitachi Metals Ltd | Electrolytic reduction precipitation method of rare earth element |
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| JPH02310390A (en) * | 1989-05-25 | 1990-12-26 | Ishihara Chem Co Ltd | Rare earth metal plating solution |
| JP2012087329A (en) * | 2010-10-15 | 2012-05-10 | Yokohama National Univ | Method for recovering iron group element and rare earth element using ionic liquid, and apparatus for recovering iron group element and rare earth element |
| JP2013204126A (en) * | 2012-03-29 | 2013-10-07 | Hitachi Metals Ltd | Electrolytic reduction precipitation method of rare earth element |
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| CN103469251A (en) * | 2013-08-26 | 2013-12-25 | 李戈登 | Novel process for fully separating rare earth elements |
| KR20160116429A (en) | 2015-03-30 | 2016-10-10 | 충남대학교산학협력단 | Apparatus for recovering neodymium matal using electrowinning |
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