블랙매스의 탄소 제거 및 금속 침출에 미치는 열처리 조건의 영향

다국어 초록 (Multilingual Abstract)

The rapid growth of the Electric Vehicle (EV) and Energy Storage System (ESS) markets is accompanied by the critical challenge of managing end-of-life lithium-ion batteries alongside their massive consumption. Black Mass, a key raw material for battery recycling, contains valuable metals such as lithium, nickel, and cobalt. However, the presence of large amounts of carbonaceous materials, such as graphite and carbon black, is a major factor hindering the efficiency of hydrometallurgical processes. In particular, these carbon materials induce matrix effects during instrumental analysis and physically interfere with acid leaching reactions by adsorbing metal ions, thereby degrading the accuracy of compositional analysis. In this study, the selective removal and optimization of carbonaceous materials using heat treatment were investigated as a pretreatment process to maximize the efficiency of hydrometallurgy and compositional analysis. Two types of NMC-based Black Mass with different properties were subjected to heat treatment for 2 hours at temperatures ranging from 500 ℃ to 800 ℃ under oxygen and nitrogen atmospheres. The changes in residual ash content, residual carbon content, and the behavior of valuable metals were systematically analyzed. Experimental results showed a high carbon removal ratio of over 99.0 % at heat treatment conditions above 600 ℃, regardless of the initial carbon content (21.45 %, 54.22 %). Notably, at 700 ℃, the residual carbon content decreased to less than 0.1%, confirming the complete removal of factors interfering with analysis and processes. XRD analysis revealed that under an oxygen atmosphere, lithium phase-transformed into a stable lithium carbonate form, which is favorable for acid leaching. In contrast, under a nitrogen atmosphere, the formation of some unstable lithium nitride and refractory lithium aluminate phases was observed. However, ICP-OES analysis applying hydrofluoric acid (HF)-based pretreatment showed that transition metals such as nickel, cobalt, manganese, and copper maintained thermal stability across the entire temperature range with negligible loss, regardless of the calcination atmosphere. Conversely, lithium showed a significant loss of up to 6.7 % due to thermal volatilization at 800 ℃. In conclusion, the optimal heat treatment condition for completely removing over 99.9 % of carbon impurities while maximizing the recovery of valuable metals, including lithium, and ensuring process safety by inducing chemically stable phases was identified as 700 ℃ under an oxygen atmosphere. The findings of this study provide key fundamental data for establishing a reliable compositional analysis protocol for Black Mass and designing high-efficiency acid leaching processes, and are expected to contribute to the optimization of sustainable battery recycling processes in the future. Keywords : Lithium-ion Battery, Black Mass, Heat Treatment, Carbon removal, Phase transformation

목차 (Table of Contents)

• List of Tables· ⅲ
• List of Figures· ⅳ
• ABSTRACT ⅵ
• 1. 서론 1
• 1.1 연구 배경1
• 1.1.1 폐배터리 자원화의 필요성 1
• 1.1.2 기기분석에서 탄소 제거의 필요성 6
• 1.2 연구 목적7
• 2. 이론 9
• 2.1 이차전지와 리튬이온전지 9
• 2.2 블랙매스 13
• 2.3 유도결합플라즈마 광방출 분광법의 원리 및 특성 16
• 3. 열처리 조건에 따른 탄소제거 효율 실험 및 결과 18
• 3.1 실험재료 18
• 3.2 실험방법 20
• 3.2.1 열처리 실험 20
• 3.2.2 탄소함량 분석 실험 22
• 3.3 실험결과 23
• 3.3.1 열처리 실험 결과·23
• 3.2.2 탄소함량 분석 실험 26
• 4. 열처리에 따른 상변화 및 금속원소 분석실험 및 결과 29
• 4.1 실험재료 29
• 4.2 실험방법 29
• 4.2.1 상변화 분석 실험29
• 4.2.2 금속원소 분석 실험 30
• 4.3 실험결과 37
• 4.3.1 상변화 분석 실험 결과 37
• 4.3.2 금속원소 분석 실험 결과 43
• 5. 결론 54
• 참고문헌56
• 국문초록62
• 감사의 글 64