Kinetics of Hydrochloric Acid Leaching of Copper from its Ore

Abstract

The effects of some experimental parameters on the copper leaching process were investigated and presented in a previous article, while in the current article kinetic models to represent the effects of leaching temperature, acid concentration, and ore particle size on the leaching rate will be examined and analyzed. The obtained results showed that none of the surface chemical reaction or the pore diffusion on its own can control the whole copper dissolution process. The mixed kinetics model which includes two different leaching processes including the surface chemical reaction and diffusion through a porous product layer was found to be suitable for describing and fitting the experimental data up to 65 % copper dissolution (X) at a high stirring speed of 1000 rpm. The apparent activation energies for pore diffusion and surface reaction were estimated to be 12.26 and 9.61 kcal/mol, respectively. Values of surface reaction rate constant in the range from 6.35´10 -4 to 5.49´10 -3 cm/sec and pore diffusion coefficient in the range from 3.58´10 -8 to 2.36´10 -7 cm 2 /sec have been obtained.