Leaching Kinetics of Mo, Ni, and Al Oxides from Spent Nickel-Molybdenum Hydrodesulfurization Catalyst in H2SO4 Solution

Abstract

Spent Ni-Mo hydrodesulfurization catalyst (HDS) includes a considerable amount of Mo, Ni, and Al and is used as an important secondary resource for the recovery of valuable metals. The effect of grinding, stirring speed, H2SO4 concentration, and temperature on the leaching rate of spent catalyst was investigated. Leaching behavior of MoO3, NiMoO4, Al2O3, and AlPO4 from spent catalyst was determined. Leaching kinetics of MoO3, NiMoO4, Al2O3, and AlPO4 was explained by Avrami Kinetic Model. Kinetic parameters such as apparent activation energy, pre-exponential factor, order of acid concentration, and Avrami coefficient were calculated and model equations were derived. Apparent activation energy values were calculated for the leaching of MoO3, NiMoO4, Al2O3, and AlPO4 from spent catalyst in H2SO4 solutions as 22.02, 41.74, 57.80, and 42.32 kJ mol(-1).