Fungal Bioleaching of Spent Hydroprocessing Catalyst: Effect of Decoking and Particle Size
. This work reports on the bioleaching of spent NiMo catalyst using Aspergillus niger. As-received and decoked catalysts of various sizes (as-received, 180-120 µm, 120-45 µm and <45 µm) were examined. Chemical analysis of the spent catalyst confirmed the presence of heavy metals including Al (38.2%), Ni (3.36%), and Mo (12.9%). SEM-EDX analysis revealed a change in the metal distribution within the spent catalyst following the decoking process. In one-step bioleaching where the fungus was inoculated together with the catalyst, fungal growth was not observed. In 2-step bioleaching where the catalyst was added three days after the start of the fungal incubation, the highest Mo (87.3%) and Al (17.20%) leaching efficiencies were obtained from the catalyst of smallest particle size (i.e. decoked grounded; <45µm) while the highest Ni leaching efficiency (94%) was achieved from the as-received spent catalyst.
Edgardo R. Donati, Marisa R. Viera, Eduardo L. Tavani, María A. Giaveno, Teresa L. Lavalle, Patricia A. Chiacchiarini
M. Islam and Y. P. Ting, "Fungal Bioleaching of Spent Hydroprocessing Catalyst: Effect of Decoking and Particle Size ", Advanced Materials Research, Vols. 71-73, pp. 665-668, 2009