Synchronous conversion and targeted separation of valuable metals from spent hydroprocessing catalysts

Abstract

Sustainable recovery of spent hydroprocessing catalysts (sHPC) is crucial to address environmental and resources issues. However, the existing recycling methods recover limited metal components due to uncontrollable phase transition and complicated separation procedures, leading to poor utilization efficiency of the sHPC. Herein, a synchronous conversion and targeted separation strategy was designed to achieve full-component recovery of the sHPC. The insoluble phases of Al/Ni/Mo/V could be completely transformed into soluble sulfate via sulfation roasting at 400 °C. The roasted sulfate products can be directly leached by water with efficiencies close to 100%. Targeted separation of the multi-ions could be achieved based on their species difference in the leachates. Anionic HV₁₀O₂₈^5- and HMoO₄^- species were co-extracted by basic trioctylamine extractant, while cationic Ni²⁺ and Al³⁺ were extracted by acidic HBL110 and P204, respectively. Benefiting from the sulfation roasting and selective extraction procedures, the recovery efficiencies of Al, Ni, Mo, and V elements achieved 97.2%, 95.8%, 94.1%, and 94.3%, respectively. The explored synchronous conversion and targeted separation strategy is an industrial-feasible candidate for sustainable utilization of the retired catalysts.