Kinetic anomalies of dissolution of sphalerite in ferric sulfate solution

Abstract During the leaching of several sphalerite concentrates in acidic ferric sulfate solution, the dissolution rate of zinc decreases with time and overall conversion does not exceed 305. The growing elemental sulfur layer on the surface of each particle was found to be the cause of this passivation. To eliminate this phenomenon, a small addition of lignosulphonate (1 g/l) into the leaching solution was found to be effective. A conversion of over 60% was obtained.