Kinetics of Pressure Acid Leaching of Zinc from Zinc Silicate Ore

The present work is concerned with the kinetic study of pressure leaching of zinc silicate ore in sulfuric acid solutions. The effects of leaching temperature, particle size, sulfuric acid concentration and agitation speed on the zinc extraction were evaluated. The results obtained show that the zinc extraction increases with increasing sulfuric acid concentration and leaching temperature. The leaching kinetics was analyzed by using a shrinking core model with diffusion control given by: 1-2/3x-(1-x)(2/3)=Kt, which represented well the experimental data. The apparent activation energy was determined to be 44.56kJ/mol at temperatures ranging between 80 and 140 degrees C.