Kinetic Study on the Leaching of Spent Catalysts of Steam Reforming Plant in Sulfuric Acid Medium

The kinetics of the spent nickel oxide catalyst (NiO/Al2O3) leaching in sulfuric acid solutions was investigated. The effects of spent catalyst particle size, acid concentration and reaction temperature on Ni extraction rate were determined. The results obtained show that extraction of about 96% of the Ni is achieved using 200 mesh spent catalyst particle size at reaction temperature of 100-120oC for 360 min reaction time with 60% sulfuric acid concentration. The solid/liquid ratio was maintained constant at 1:5 g/ml. The leaching kinetics indicates that chemical reaction at the surface of the particles and shrinking sphere is the rate controlling process during the reaction for H2SO4. The activation energy was determined as about 33.65 kJ/mol.