Bioleaching kinetics of a spent refinery catalyst using Aspergillus niger at optimal conditions

The kinetics of bioleaching of Mo, Ni, and Al from spent hydrocracking catalyst, using Aspergillus niger was studied. The four most effective bioleaching variables were selected in accordance with the Plackett–Burman design and were further optimized via central composite design (CCD). The optimal values of the variables for maximum multi-metal bioleaching were as follows: particle size 150–212μm, sucrose 93.8g/L, pulp density 3%w/v, and pH 7. …