Akademik Veri Yönetim Sistemi
Hydrometallurgy, cilt.243, 2026 (SCI-Expanded, Scopus)
Spent hydrodesulfurization (HDS) catalysts are an important secondary resource for strategic metals. In this work, a novel solvometallurgical approach employing a choline chloride:p-toluene sulfonic acid (ChCl:PTSA) deep eutectic solvent (DES) was developed for the leaching and selective recovery of Co, Mo and Al by chemical precipitation. The effect of temperature, time, solid-to-liquid ratio, stirring speed, and ChCl:PTSA molar ratio on leaching performance were systematically examined. Optimum conditions were determined as 393 K, 3 h, 200 rpm, and a 1:1 M ratio of ChCl:PTSA, achieving leaching efficiencies of 93% for MoO₃, 88% for CoO, and 45% for Al₂O₃. Leaching kinetics followed the Avrami model, with apparent activation energies of 50.3, 51.5, and 53.9 kJ mol−1 for MoO3, CoO, and Al2O3, respectively. Subsequently, Co, Mo, and Al were selectively recovered as their corresponding oxides through a pH-controlled sequential precipitation, evaporative crystallization, and calcination process. This study demonstrates, for the first time, the potential of ChCl:PTSA-based DES for selective and sustainable metal recovery from spent HDS catalysts, highlighting its promise as an alternative to conventional hydrometallurgical processes.