<p>Lithium-ion battery (LIB) recycling slag is an underutilized waste stream that is typically landfilled or used as low-value construction material, despite containing residual lithium (5–10 wt% Li₂O). In this study, lithium recovery from LIB recycling slag was investigated through chlorination roasting using CaCl₂ under a controlled inert atmosphere, with a particular focus on the effect of temperature (700–1100&#xa0;°C) on lithium recovery and impurity behavior. As the roasting temperature increased, the total mass of the system decreased gradually up to 900&#xa0;°C, followed by a sharp reduction up to 1100&#xa0;°C, reflecting the temperature-dependent transformation and volatilization of oxide components in the slag. Lithium recovery increased modestly from 2.6% to 10.7% between 700 and 900&#xa0;°C, followed by a rapid increase to approximately 90% in the 1000–1100&#xa0;°C range. Alkali metals (K and Na) and Pb exhibited high volatilization into the gas phase (80–100%) at elevated temperatures, whereas Mg, Mn, and Cu showed limited volatilization (20–30%). Phase analysis revealed the formation of LiAlO₂, Ca₂Al₂SiO₇, Li₅AlSi₂O₈, Ca₂SiO₃Cl₂, and Ca₃Al₂Si₃O₁₂ in the 700–1000&#xa0;°C range, while chloride-containing phases were not detected at 1100&#xa0;°C. Technical grade LiCl (approximately 90–98%) was experimentally obtained, although product purity slightly decreased at higher temperatures due to the coevaporation of impurity chlorides. These results demonstrate that temperature-optimized chlorination roasting enables effective lithium recovery from LIB recycling slag and provides a viable pathway for converting this waste residue into a secondary lithium resource, thereby contributing to improved resource efficiency and waste valorization in LIB recycling systems.</p> Graphical Abstract <p></p>