Aluminum recovery from industrial spent catalyst

An alumina-based industrial spent catalyst generated from a catalytic reforming unit (CRU) contains a substantial quantity of aluminum, making it a promising secondary resource for sustainable metal recovery. Improper disposal of these materials leads to significant environmental and economic challenges. This study investigates a sequential, integrated hydrometallurgical process designed to recover aluminum from a CRU-derived spent catalyst. The recovery scheme relies on initial organic acid leaching followed by a subsequent, downstream electrolysis step. In the primary stage, organic acid leaching alone achieved a leaching efficiency of approximately 90%, successfully dissolving the target metal into an aqueous phase. The resulting leachate was subjected to final aluminum recovery, and the effect of voltage on aluminum recovery was analyzed. Experimental results demonstrated that increasing the applied voltage enhanced electrochemical reaction rates and accelerated mass transfer, thereby improving extraction yields. Under optimum operating conditions, the overall integrated process achieved a total aluminum removal efficiency of approximately 95%. Furthermore, the use of organic acids offers an environmentally benign alternative to conventional mineral acids due to their biodegradability and low toxicity, effectively minimizing secondary pollution. Ultimately, these findings demonstrate that coupling organic acid leaching with downstream electrolysis provides an efficient, sustainable approach for recovering aluminum from refinery waste, directly supporting industrial waste minimization and circular economy practices.