Sustainable recovery of molybdenum, cobalt, and bismuth from hazardous spent selective oxidation catalysts via an efficient hydrometallurgical process

Abstract

An Eh–pH-informed three-stage hydrometallurgical route is presented for spent Mo–Co–Bi selective-oxidation catalysts. The flowsheet integrates NaOH leaching, H₂SO₄ leaching, crystallization, and selective precipitation under optimized conditions. Recoveries reached 94.9% Mo, 82.2% Bi, and 97.7% Co, demonstrating practicality and scalability for reclaiming strategic metals from complex multicomponent catalyst wastes.