A feasibility study for a circular approach in oil refining: Metals recovery from hydrodesulphurization catalysts

Highly Selective Separation and Recovery of Molybdenum from Spent Catalysts by Constructing a Glass-Phase Extraction System

“…28 However, there are characteristic absorption bands of [6] Ni 2+ and [5] Ni 2+ at 7200, 13,000, and 20,000−21,000 cm −1 , respectively, which was attributed to the coextraction of 49.8% Mo 6+ with high field strength into the glass network structure to attract O 2− . 29 With the increase of melting temperature, the characteristic absorption of [6] Ni 2+ and [5] Ni 2+ in the spectra weakened and disappeared, respectively, while the band of [4] Ni 2+ at 18,300 cm −1 shifted to a higher wavelength, indicating an increase in its vibrational frequency. Based on the above results, the designed binary glass extraction system selectively extracted Al 3+ and Ni 2+ from spent catalysts at melting temperatures greater than 1400 °C, accompanied by Mo 6+…”

“…Further, in the optical spectra, loaded glasses obtained by different melting temperatures (Figure 4c) showed that the coextraction of Mo affected the Ni coordination sites in the glass network structures. Under 1300 °C, the strong absorption bands near 8500, 15,600, and 18,300 cm −1 are diagnosed as T 1 (F) → 3 A 2 (F), 3 T 1 (F) → 3 T 1 (P), and 3 T 1 (F) → 3 T 1 (P) transitions of [4] Ni 2+ , respectively. 28 However, there are characteristic absorption bands of [6] Ni 2+ and [5] Ni 2+ at 7200, 13,000, and 20,000−21,000 cm −1 , respectively, which was attributed to the coextraction of 49.8% Mo 6+ with high field strength into the glass network structure to attract O 2− .…”

“…However, due to deposition of metal sulfides, carrier sintering, and structural collapse, the global accumulation of spent HDS catalysts deactivated amounts to 170,000 ton/year. 4 Moreover, spent HDS catalysts contain higher concentrations of Mo and Ni than those in primary ores, which has led to them being classified as hazardous wastes. 5 Therefore, the extraction and recovery of Mo from spent HDS catalysts is a sustainable strategy for resources, accompanied by the reductions of the environmental burden from mining and the disposal of hazardous waste.…”

“…MoNi/γ-Al 2 O 3 catalysts are widely used for hydrodesulfurization (HDS) in producing ultralow-sulfur/nitrogen fuel. However, due to deposition of metal sulfides, carrier sintering, and structural collapse, the global accumulation of spent HDS catalysts deactivated amounts to 170,000 ton/year . Moreover, spent HDS catalysts contain higher concentrations of Mo and Ni than those in primary ores, which has led to them being classified as hazardous wastes .…”