Cobalt (Co) is mainly used to prepare cathode materials for lithium-ion batteries (LIBs) and binder metals for WC-Co hard metals. Developing an effective method for recovering Co from WC-Co waste sludge is of immense significance. In this study, Co is extracted from waste cemented carbide soft scrap via mechanochemical milling. The leaching ratio of Co reaches approximately 93%, and the leached solution, from which impurities except nickel are removed by pH titration, exhibits a purity of approximately 97%. The titrated aqueous Co salts are precipitated using oxalic acid and hydroxide precipitation, and the effects of the precipitating agent (oxalic acid and hydroxide) on the cobalt microstructure are investigated. It is confirmed that the type of Co compound and the crystal growth direction change according to the precipitation method, both of which affect the microstructure of the cobalt powders. This novel mechanochemical process is of significant importance for the recovery of Co from waste WC-Co hard metal. The recycled Co can be applied as a cemented carbide binder or a cathode material for lithium secondary batteries.

Abstract
1. 서 론
2. 실험방법
3. 결과 및 고찰
4. 결 론
References

• 이재성(충북대학교 도시·에너지·환경 융합학부) | Jaesung Lee (Department of Urban, Energy, and Environmental Engineering, Chungbuk National University)
• 김민구(충북대학교 도시·에너지·환경 융합학부) | Mingoo Kim (Department of Urban, Energy, and Environmental Engineering, Chungbuk National University)
• 김슬기(충북대학교 신소재공학과) | Seulgi Kim (Department of Advanced Materials Engineering, Chungbuk National University)
• 이동주(충북대학교 도시·에너지·환경 융합학부/충북대학교 신소재공학과) | Dongju Lee (Department of Urban, Energy, and Environmental Engineering, Chungbuk National University/Department of Advanced Materials Engineering, Chungbuk National University) Corresponding Author