Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Pyro-Electrochemical Reduction of a Mixture of Rare Earth Oxides and NiO in LiCl molten Salt

LiCl 용융염에서 NiO를 혼합한 희토류 산화물의 파이로 전해환원 특성

  • Lee, Min-Woo (Department of Chemical Engineering, Chungbuk National University) ;
  • Jeong, Sang Mun (Department of Chemical Engineering, Chungbuk National University)
  • 이민우 (충북대학교 화학공학과) ;
  • 정상문 (충북대학교 화학공학과)
  • Received : 2016.12.05
  • Accepted : 2017.01.31
  • Published : 2017.06.01
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Abstract

An electrochemical reduction of a mixture of NiO and rare earth oxides has been conducted to increase the reduction degree of rare earth oxides. Cyclic voltammetry (CV) measurement was carried out to determine the electrochemical reduction behavior of the mixed oxide in molten LiCl medium. Constant voltage electrolysis was performed with various supplied charges to understand the mechanism of electrochemical reduction of the mixed oxide as a working electrode. After completion of the electrochemical reduction, crystal structure of the reaction intermediates was characterized by using an X-ray diffraction method. The results clearly demonstrate that the rare earth oxide was converted to RE-Ni intermetallics via co-reduction with NiO.

LiCl 용융염에서 희토류 산화물의환원율을 높이기 위해 NiO와 혼합하여 전해환원을실시하였다. Cyclic voltammetry (CV) 실험을 통해 LiCl 용융염 내에서 혼합산화물의 전기화학적 환원거동을 조사하였다. 혼합산화물로 제작된 환원전극과 그라파이트 산화전극 사이에 일정한 작동전압을 인가하여 이론전하량 대비 다양한 전하량을 공급한 후 중간생성물의 결정구조를 XRD를 이용하여 분석하였다. NiO 산화물을 첨가함으로써 전기전도성이 좋은 Ni 금속 주위로 희토류 산화물이 환원되어 RE-Ni 합금형태의 금속으로 완전히 전환되었으며, 합금을 형성하는 반응 메커니즘을 제시하였다.

Keywords

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