폐 반응용기로부터 침출된 황산리튬 용액 기반 수산화리튬 제조 연구

다국어 초록 (Multilingual Abstract)

This study aims to establish a fundamental process for producing high-purity lithium hydroxide (LiOH) from lithium sulfate (Li2SO4) solution recovered through sulfuric-acid leaching of spent reaction vessels used in cathode production. The recovered leachate contained high concentrations of metallic impurities such as Na, K, Mg, Ca, and Al, making direct conversion to LiOH impractical; therefore, a pretreatment step using cation and anion exchange resins was applied. With 10g of cation-exchange resin and 50g of anion-exchange resin, the solution pH was adjusted to the neutral range (6–7), enabling effective impurity removal: over 90% for Al and approximately 70–75% for Mg, Ca, Na, K, and Ni. A subsequent double-displacement precipitation reaction using Ba(OH)2 revealed that the reaction temperature and the [OH]:[Li] molar ratio were the key parameters controlling conversion behavior. Excess OH- promoted the formation of dissolved and complexed metal species, reducing the filtrate purity, whereas at 70°C with an [OH]:[Li] ratio of 1:1, SO42- was most stably precipitated as BaSO4, yielding the highest performance: a conversion rate of 91.91% and a LiOH purity of 98.84%. XRD analysis of the recovered solid confirmed the coexistence of LiOH·H2O and LiOH phases, while the precipitate exhibited single-phase BaSO4, indicating complete sulfate removal. Overall, this study experimentally demonstrates that LiOH can be produced from Li2SO4 leachate derived from spent reaction vessels through a sequential process of impurity removal, precipitation conversion, and drying, providing baseline data for future process design and industrial LiOH recovery.

목차 (Table of Contents)

• Ⅰ. 서론 1
• 1. 연구 배경 및 필요성 1
• Ⅱ. 이론적 배경 4
• 1. 리튬 원료와 전구체 4
• 1.1 리튬의 개요 4
• 1.2 리튬화합물 5
• 1.2.1 탄산리튬(Li2CO3) 5
• 1.2.2 수산화리튬(LiOH) 7
• 1.2.3 Li2CO3와 LiOH의 비교 8
• 2. 리튬 자원 10
• 2.1 리튬 자원의 분포와 형태 10
• 2.2 염호에서 리튬 추출 공정 12
• 2.2.1 증발 농축 공정(Evaporation process) 15
• 2.2.2 화학적 침전 공정(Precipitation process) 16
• 2.2.3 용매추출 및 이온교환(Solvent extraction / Ion-exchange) 19
• 2.2.4 전기화학적 분리(Electrodialysis, Bipolar membrane ED) 19
• 2.3 광석에서 리튬 추출 공정 20
• 2.3.1 산 처리법(Acid process) 22
• 2.3.2 알칼리 처리법(Alkaline process) 23
• 3. 사용 후 리튬이온배터리(LIB) 재활용 기술 25
• 3.1 전처리 공정(Pretreatment) 27
• 3.1.1 방전(Discharging) 29
• 3.1.2 기계적 전처리(Mechanical treatment process) 30
• 3.1.3 열처리(Thermal preliminary treatment processes) 31
• 3.1.4 화학적 전처리(Chemical preliminary treatment processes) 32
• 3.2 건식제련 공정(Pyrometallurgy) 33
• 3.2.1 제련(Smelting) 35
• 3.2.2 배소(Roasting) 36
• 3.3 습식제련 공정(Hydrometallurgy) 37
• 3.3.1 침출법(Leaching) 38
• 3.3.2 침전법(Precipitation) 39
• 3.3.3 용매추출법(Solvent extraction) 40
• Ⅲ. 실험 재료 및 방법 41
• 1. 개요 41
• 1.1 실험 재료 분석 41
• 1.2 실험 장비 43
• 2. 실험 방법 46
• 2.1 수산화리튬 제조 공정도 46
• 2.2 리튬추출액 내 불순물 제거 48
• 2.3 황산리튬 용액으로부터 수산화리튬 제조 50
• Ⅳ. 실험 결과 및 고찰 55
• 1. 이온교환수지를 통한 불순물 제거 55
• 1.1 양이온교환수지(MC-10H) 처리 55
• 1.2 음이온교환수지(MA-10OH) 처리 59
• 1.3 양이온 및 음이온교환수지 혼합 처리 63
• 2. 알칼리성 침전제(Ba(OH)2)를 통한 수산화리튬 제조 68
• 2.1 반응 온도 및 몰비 변화에 따른 수산화리튬 생성 거동 68
• 2.2 반응 온도 및 몰비 변화에 따른 수산화리튬 전환율 평가 71
• 2.3 반응 온도 및 몰비 변화에 따른 수산화리튬 순도 평가 75
• 2.4 수산화리튬 결정화 및 상 분석 79
• Ⅴ. 결론 83
• 참고문헌 86