Enhancement of leaching of cobalt and lithium from spent lithium-ion batteries by mechanochemical process
(1. School of Chemical Engineering, China University of Mining and Technology, Xuzhou 221116, China;
2. Advanced Analysis and Computation Center, China University of Mining and Technology, Xuzhou 221116, China)
2. Advanced Analysis and Computation Center, China University of Mining and Technology, Xuzhou 221116, China)
Abstract: A mechanochemical method with SiO2 as the grinding aid was used to enhance the leaching efficiencies of Co and Li from spent lithium batteries (LIBs). Experiment results show that the optimal leaching efficiencies of 94.91% for Co and 97.22% for Li were obtained under the parameters of SiO2/LiCoO2 mass ratio of 1:1, grinding speed of 500 r/min and grinding time of 30 min in citric acid. Characterization results indicate that the surficial properties of LiCoO2 were changed after mechanochemical grinding treatment due to the newly generated surfaces on LiCoO2. Meanwhile, the incompletely coordinated atomic structure and defective lattice structure lead to the activation of LiCoO2. The reduction effect of carbon black on Co3+ under the action of mechanical forces increases its leaching efficiencies in the citric acid solution. The proposed process was found efficiently to recover Co and Li from LiCoO2.
Key words: mechanochemical grinding; leaching; spent lithium-ion batteries; surficial properties; reaction mechanism