Petroleum refineries must pay attention to spent hydroprocessing catalysts particularly since they are hazardous toxic wastes. This study focuses on the progress in metal reclamation and disposal methods used for dealing with the environmental problem of spent hydroprocessing catalysts. Studies have been conducted with the aim either to increase the efficiency of metals recovery using established methods or to develop novel methods. Leaching studies used inorganic agents such as solutions of Na2O3/H2O2 and strong acids or bases, alumina containing compounds and water soluble organic acids. The extracted metals were impregnated on recovered alumina to synthesize fresh catalyst. Structural analysis of spent catalyst, recovered support material, and synthesized catalyst from extracted metals suggested successful recovery and recycling of metals. This work offers an insentive to the industrial practice for waste minimization, recycling of the extracted metals, and the noncorrosive, eco-friendly approach for metal extraction from spent catalyst.
