Desulfurization of coal pyrite tailings with ozone

Abstract

Mining is an important sector of the economy, and in the southern region of Brazil, coal mining stands out. This activity generates waste with a high pyritic content, which causes environmental problems such as acid mine drainage (AMD). Therefore, studies that aim to beneficiate or treat this waste are of high relevance. In this study, an alternative for desulfurizing pyritic waste using ozone was investigated. Ozone treatment of mining tailings suspension was evaluated as a new strategy for sulfur removal. Particle size analysis, sulfate content, ferrous ion concentration (and total iron), pH, Eh, conductivity, and X-ray fluorescence were performed. Furthermore, a kinetic analysis of ozone consumption was established. The behavior of sulfate and hydrogen ion concentrations indicates that sulfuric acid is the main reaction product, and conductivity suggests that ion release is continuous over the ozonation time. A reaction kinetics with ??1.2 was found for ozone depletion, which aids in predicting the dosage to be applied on a larger scale. This study represents a contribution to the search for alternatives for treating pyritic waste and contributes to the understanding of the reaction rate of ozone consumption in this type of reaction.