Sulfuric Acid-Based Leaching for Purification of Ni-Co Recovered from Pyrometallurgically Recycled Spent Lithium-Ion Batteries

Dohyun Han; Juheon Lee; Sucheol Han; Hunmook Yi

doi:10.7844/kirr.2026.35.4.77

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2026 Vol.35, Issue 4 Preview Page Next Page

Sulfuric Acid-Based Leaching for Purification of Ni-Co Recovered from Pyrometallurgically Recycled Spent Lithium-Ion Batteries 사용 후 리튬이온전지 건식제련 회수체로부터 Ni-Co 합금의 고순도화를 위한 황산 기반 선택적 침출 공정

31 August 2026. pp. 77-86

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Abstract

Lithium-ion batteries (LIBs) are increasingly used in electric vehicles (EVs) and energy storage systems (ESSs), with high energy density LiNi_xCo_yMn_1−x−yO₂ (NCM) widely adopted as an EV cathode material. Carbothermic pyrometallurgical recycling has attracted considerable attention because it enables large-scale treatment of whole battery cells without the need for additional additives and pre-treatment. However, studies on purification of Ni-Co products generated during the process remain limited. In this study, a sulfuric acid-based selective leaching process was developed to selectively remove impurity phases and refine Ni-Co from pyrometallurgically recycled NCM obtained through carbothermic pyrometallurgical recycling of NCM batteries. Pyrometallurgically recycled NCM mainly consisted of Ni-Co, MnO, and LiAlO₂, and the leaching behavior was investigated as a function of sulfuric acid concentration (1~7wt%) and leaching time (0.5, 1, and 2h). The results showed that Mn exhibited leaching efficiencies exceeding 95% under all conditions, while Li achieved a maximum leaching efficiency of 94.75% with increasing sulfuric acid concentration and leaching time. In contrast, the leaching efficiency of Ni and Co remained below 11% under all conditions, demonstrating the selective removal of MnO and LiAlO₂. Evaluation of the purity and recovery of Ni-Co in the leaching residue revealed that the optimal condition was 3wt% H₂SO₄ with a leaching time of 1h, yielding a Ni-Co purity of 86.99% and a recovery of 95.50%. The proposed process selectively removes impurities and refines Ni-Co, enhancing the economic and industrial feasibility of spent LIB pyrometallurgical recycling.

Keywords

Carbothermic Reduction

Leaching

LIB Recycling

NCM

Pyrometallurgy

리튬이온전지(Lithium-ion batteries, LIBs)는 전기자동차와 에너지저장장치 시장의 확대로 인해 그 사용량과 재활용 필요성이 증가하고 있다. LiNi_xCo_yMn_1−x−yO₂(NCM)은 대표적인 양극활물질의 일종이며, 해당 소재에 대한 탄소환원 기반 건식제련 공정에 대한 다수의 연구들이 이루어지고 있다. 그러나 해당 공정에서 생산된 Ni–Co 합금의 회수 및 고순도화에 관한 연구는 상대적으로 부족한 실정이다. 본 연구에서는 NCM계 LIB의 탄소환원 건식제련 회수체를 대상으로 황산 기반 선택 침출을 수행하여 Ni-Co의 고순도화 공정을 개발하였다. 회수체는 주로 Ni-Co, MnO 및 LiAlO₂로 구성되어 있으며, 황산 농도(1~7wt%) 및 침출 시간(0.5, 1, 2h)에 따른 원소별 침출 거동을 평가하였다. 그 결과, Mn은 모든 조건에서 95% 이상의 침출률을 나타내었으며, Li은 황산 농도 및 침출 시간의 증가에 따라 최대 94.75%의 침출률을 나타냈다. 반면, Ni 및 Co의 침출률은 모든 조건에서 11% 이하로 유지되어 MnO 및 LiAlO₂의 선택적 제거가 가능함을 확인하였다. 침출 후 잔사에 대해 Ni-Co의 순도와 회수율을 평가한 결과, 3wt% 황산 및 1h 침출 조건에서 각각 86.99%와 95.50%를 나타내어 최적 조건으로 도출되었다. 본 연구에서 제안한 공정을 통해 폐배터리 건식제련 공정의 경제성 향상 및 산업적 활용 확대에 기여할 수 있을 것으로 기대된다.

키워드

건식제련

침출

탄소환원

LIB 재활용

NCM

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Information

Publisher :The Korean Institute of Resources Recycling
Publisher(Ko) :한국자원리싸이클링학회
Journal Title :Resources Recycling
Journal Title(Ko) :자원리싸이클링
Volume : 35
No :4
Pages :77-86
Received Date : 2026-06-08
Revised Date : 2026-07-16; 2026-08-10
Accepted Date : 2026-08-11
DOI :https://doi.org/10.7844/kirr.2026.35.4.77

Resources Recycling ISSN:2765-3439(Print) 2765-3447(Online) 자원리싸이클링

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