Kinetic modeling of the leaching of LiCoO2 with phosphoric acid

In this article, we analyze the leaching kinetics with phosphoric acid of LiCoO2 samples from spent Li-ion batteries and commercial LiCoO2. The purpose was to study the mechanism by which the extraction reaction of cobalt and lithium is produced from the solid samples. The experimental results showed that raising the temperature and the reaction time contributed to improving both the extraction of Li and Co from the structure. The leaching rate of the metals from both samples in the phosphoric acid solution could be expressed as: ln (1 - X) = -b(1) [ln (1 + b(2)t) - b(2)t/1+b(2)t]. The morphology of the solid revealed that the dis-solution reaction of the samples develops from preferential growth of active sites, points susceptible to chemical interaction, occurring in one direction, giving rise to the start and progress of the reaction. The generation of these sites in the LCO-H3PO4 reaction system is of the sequentialtype. The apparent activation energy values for the leaching of Co and Li would indicate that the surface chemical reaction is the rate-controlling step during this dissolution process. (C) 2020 The Author(s). Published by Elsevier B.V.