폐모터 내 NdFeB 자석으로부터 Nd 회수를 위한 비철제련슬래그 기반 건식 공정 연구

다국어 초록 (Multilingual Abstract)

With the increasing generation of end-of-life electric vehicle （EV） motors,
the recycling of neodymium （Nd） contained in Nd–Fe–B magnets has
become increasingly important. In this study, a pyrometallurgical
recycling process using non-ferrous smelting slag flux was proposed for
Nd recovery from waste EV motors. Waste EV motors containing Nd–Fe
B magnets were melted at approximately 1600 °C under an air
atmosphere, and selective oxidation of Nd was induced by Fe₂O₃ addition,
followed by partitioning into the slag phase. The effects of slag flux
addition ratio and Fe₂O₃ content on Nd recovery behavior were
investigated. As the slag flux addition ratio increased, Nd partitioning
into the slag phase was enhanced, and the optimal Nd recovery of
approximately 80% was achieved at a slag flux addition ratio of 30 wt%.
In addition, 2 wt% Fe₂O₃ was identified as the optimum condition for
stable Nd₂O₃ formation and efficient slag-metal separation. The
non-ferrous smelting slag flux exhibited chemical compositions and phase
characteristics similar to those of conventional fayalite flux, resulting in
comparable Nd recovery performance. Furthermore, the effects of
crucible materials on Nd recovery behavior were evaluated. The carbon
crucible exhibited high Nd recovery efficiency; however, severe slag
foaming and crucible erosion were observed during the melting process.
Alumina and MgO crucibles showed similar Nd recovery behavior and
stable process characteristics, whereas the zirconia crucible exhibited
relatively higher Nd loss. Overall, the proposed non-ferrous smelting slag
flux-based pyrometallurgical process demonstrated the potential for
effective Nd recovery from waste EV motors and its applicability as a
sustainable rare earth recycling process.

목차 (Table of Contents)

• Ⅰ. 서론 1
• 1. 연구 배경 및 필요성 1
• Ⅱ. 이론적 배경 5
• 1. 희토류 원소 및 Nd 5
• 1.1 희토류 원소의 특성 및 산업적 중요성 5
• 1.2 Nd 8
• 1.2.1 Nd의 물리·화학적 특성 9
• 1.2.2 Nd의 산화 거동 및 열역학적 특성 9
• 2. 영구자석 12
• 2.1 영구자석의 종류 및 특성 12
• 2.2 Nd-Fe-B 13
• 2.2.1 Nd–Fe–B 자석의 조성 및 구조 14
• 2.2.2 Nd–Fe–B 자석의 자기적 및 물리적 특성 15
• 3. 전기자동차 구동 모터 17
• 3.1 전기차 모터의 기본 구조 17
• 3.2 전기차 모터의 작동 원리 19
• 3.3 모터 내 Nd-Fe-B 자석의 적용 및 역할 20
• 4. 슬래그 21
• 4.1 슬래그의 역할 21
• 4.2 슬래그의 종류 22
• 4.3 슬래그의 물리·화학적 특성 23
• 4.4 FeO-SiO2계 슬래그· 25
• 4.5 비철제련슬래그 27
• 5. 기존 Nd 재활용 공정 27
• 5.1 습식제련 공정 (Hydrometallurgy) 28
• 5.2 건식제련 공정 (Pyrometallurgy) 29
• Ⅲ. 실험 재료 및 방법 32
• 1. 개요 32
• 2. 실험 재료 32
• 2.1 폐모터 내 회전자 32
• 2.2 Slag flux 및 산화제 35
• 3. 실험 장비 38
• 4. 실험 설계 40
• 4.1 slag flux 조성 및 첨가량 설정 40
• 4.1.1 slag flux 조성 선정 40
• 4.1.2 slag flux 첨가량 선정 42
• 4.2 산화제 선정 및 첨가량 설정· 45
• 4.2.1 산화제 선정 45
• 4.2.2 산화제 첨가량 선정 47
• 4.3 반응 온도 설정 50
• 4.4 비철제련슬래그 첨가제 적용 설계· 52
• Ⅳ. 실험 결과 및 고찰 56
• 1. Fayalite flux 첨가량에 따른 Nd 회수 거동 56
• 2. 산화제(Fe2O3) 첨가량에 따른 Nd 회수 특성 64
• 3. 비철제련슬래그 적용 평가 69
• 3.1 Fayalite flux 최적조건을 적용한 비철제련슬래그 flux 활용 69
• 3.2 도가니 재질에 따른 Nd 회수 거동 74
• Ⅴ. 결론 86
• 참고문헌 89