Abstract
In this study, lithium was recovered from LiFePO(4) (LFP) cathode active materials through a two-step thermal process combining hydrogen reduction and chlorination roasting. Hydrogen reduction was conducted while varying temperature and holding time to promote oxygen removal from LFP and induce phase separation into Li(3)PO(4) and iron phosphides (FeP and Fe(2)P). Based on stoichiometric assessment using the degree of LFP decomposition and the reduction in oxygen moles, the optimal hydrogen-reduction condition was determined to be 900 °C for 1 h. Subsequently, CaCl(2) was selected as an appropriate chlorination agent using thermodynamic considerations, and the hydrogen-reduced product was reacted with CaCl(2) to convert Li(3)PO(4) into water-soluble LiCl. The mass of LiCl produced was quantified as a function of reaction temperature. Water leaching enabled the separation of LiCl from the insoluble residues, resulting in an overall lithium recovery of 71.7%.