Stepwise extraction of Cu, Co, and Ni from hazardous waste: A novel process based on ammonia leaching and 2-((4-butylphenoxy)methyl)pyridine (BMPY) extraction system

Abstract

The extraction of Cu, Co, and Ni from spent batteries and spent catalysts is crucial for resource recovery and environmental pollution reduction. Ammonia leaching offers a promising alternative in the hydrometallurgical treatment of these hazardous waste due to its selective leaching properties. However, the development of this method has been impeded by the lack of efficient extractants. In this work, an efficient extractant, 2-((4-butylphenoxy)methyl)pyridine (BMPY), was designed and synthetized. Utilizing the high affinity of BMPY for Cu, Co, and Ni and exploiting the different ionic association states of these metals at different pH levels, an effective process for separating Cu, Co, and Ni from ammonia leach solution was proposed, producing CuSO4, CoSO4, and NiSO4 with over 99.9 % purity. Mechanism investigations and pilot-scale experimental validation have demonstrated that the ammonia leaching-BMPY extraction process is a viable method for extracting Cu, Co, and Ni from hazardous waste, with significant potential for industrial application.