Removal of Metal Impurities from the Spent Hydroprocessing Catalyst and Acid Leaching Kinetics of Aluminum

Abstract

The impurity metal of Al in spent hydroprocessing catalyst (Mo-Ni/Al2O3) was removed by HCl, and the metals of Mo and Ni were preliminarily enriched. The results show that the leaching efficiency of Al was 88.62%, and the leaching efficiency of Mo and Ni were 16.32% and 28.74%, respectively. The results were achieved under optimal leaching conditions: the particle size was 150 μm, the concentration of HCl was 4 mol/L, the leaching temperature was 90 °C, and the leaching time was 120 min. The kinetics of the leaching behavior of Al showed that the acid leaching reaction of Al was in accorded with the equation 1-2/3X-(1-X) 2/3=K2t, R2=0.97734, which was controlled by internal diffusion. X-ray diffraction analysis of the leaching residue revealed the existence of residual metals Mo(MoO3, MoO2(ClO4)2)and Ni(NiS). The separation of Al from Mo and Ni has been preliminarily realized, which is conducive to further efficient recovery of Mo and Ni.