Resources Recycling (자원리싸이클링)

The Korean Institute of Resources Recycling (한국자원리싸이클링학회)
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Recovery of Rare Earth Elements from Nd Magnet Scrap Using PVC

PVC에 의한 네오디뮴 자석 스크랩으로부터 희토류 회수

  • Lee, So-Yeong (School of Materials Science and Engineering, Kyungpook National University) ;
  • Park, Sung-Hun (School of Materials Science and Engineering, Kyungpook National University) ;
  • Son, Injoon (School of Materials Science and Engineering, Kyungpook National University) ;
  • Sohn, Ho-Sang (School of Materials Science and Engineering, Kyungpook National University)
  • 이소영 (경북대학교 신소재공학부) ;
  • 박성훈 (경북대학교 신소재공학부) ;
  • 손인준 (경북대학교 신소재공학부) ;
  • 손호상 (경북대학교 신소재공학부)
  • Received : 2017.11.21
  • Accepted : 2017.12.27
  • Published : 2018.02.28
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Abstract

A large amount of Nd-Fe-B magnet scraps are generated during magnet manufacture process. In this study, selective chlorination of the rare earth elements by hydrogen chloride gas which obtained from the pyrolysis of polyvinyl chloride (PVC) was investigated. In thermogravimetric analysis, drastic weight loss was occurred at about 500 K and 710 K. At the isothermal experiments, the weight loss reaches about 30% above 673 K. XRD patterns characterized that after each experiments, ${\alpha}$-Fe, Nd oxychloride, Nd chloride, and Fe chlorides were formed, and the leaching residues remain only ${\alpha}$-Fe. The yields of Nd, Dy, and Fe for the isothermal experiment were increased with temperature and peaked at 873 K. As PVC ratio increased, the yields of Nd, Dy and Fe were also increased.

Nd-Fe-B 자석의 제조공정에서 많은 양의 자석 스크랩이 발생한다. 본 연구에서는 PVC의 열분해에서 발생하는 염화수소 가스에 의한 희토류 원소의 선택적 염화반응에 대하여 조사하였다. 열중량 분석에서 약 500 K과 710 K에서 급격한 무게변화가 일어났다. 등온 실험에서 673 K 이상에서 무게 감소율이 약 30%에 도달하였다. 각 실험 이후 잔사의 XRD 패턴에서 ${\alpha}$-Fe와 Nd oxychloride, Nd 염화물, Fe 염화물이 나타났으며, 수침출 이후의 잔사에서는 ${\alpha}$-Fe만 남았다. 등온실험에서 Nd와 Dy, Fe의 회수율은 반응 온도가 높을수록 증가하는 경향을 보였고, 873 K에서 가장 높게 나타났다. PVC의 비율이 증가할수록 Nd와 Dy, Fe의 회수율 또한 증가하였다.

Keywords

References

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