Cyclic voltammetry applied to evaluate reactivity in sulfide mining residues

Oxidation of sulfide present in mining residues can generate contaminating acid effluent known as acid rock drainage. Prediction and control of acid rock drainage are critically important to the mining industry because of the environmental impact resulting from the sulfide oxidation. Due to its particular reaction kinetics, once acid drainage has begun, it is very difficult to control without a substantial economic investment. For this reason, efficient prediction and prevention programs, which monitor mining waste reactivity, are required to limit the oxidation of sulfide-bearing residues before damage to the environment occurs. In this work, the authors evaluated mining waste reactivity under oxidizing conditions as a function of its voltammetric behavior before and during alteration under simulated natural conditions produced in the laboratory. This method is supported by conventional mineralogical characterization of the mineral samples and chemical quality of the effluents produced during the simulated alteration process kinetics.