Dissolution kinetics of sphalerite in acidic ferric chloride leaching

This paper presents a study for leaching kinetics of sphalerite concentrate in FeCl3-HCl solution. The shrinking core model was applied to the results of experiments investigating the effects of stirrer speed of 200-600 rpm, ferric ion concentration in range of 0-1 M, solid/liquid ratio in range of 1/100-1/5, leaching temperature range of 40-80 degrees C and particle size on zinc dissolution rate. The activation energy for the leaching process was found to be 45.30 kJ/mol and the Arrhenius constant was calculated to be 5.454 s(-1). The order of reaction for ferric ion concentration, solid/liquid ratio and particle size were also obtained. The rate of the reaction based on reaction-controlled process can be expressed as, [1 - (1 - alpha)(1/3)] = kappa(0)(Fe3+)(0.36)((rho S/L))(-0.33) r(0)(-0.97) exp((-45300/RT))t. The dissolution of sphalerite with acidic ferric chloride solution was found to be controlled by reaction-controlled process. (c) 2005 Elsevier B.V. All rights reserved.