Analysis of the effects of natural organic matter in zinc beneficiation

Abstract

In this study, we present the analysis of the effects of Natural Organic Matter (NOM) in zinc beneficiation from abandoned mine tailings using bioleaching technologies. We used standardized Suwannee River Humic Acid (SRHA) as the NOM source to analyze the importance of the quality of the process waters and the possible side effects of NOM accumulated on mine tailings when exposed to environmental conditions. Our study proposes the use of process waters as an important variable to maintain high process efficiency. Concentrations of 20 ppm of SRHA suspended in the bioleaching medium reduced the Zn removal efficiency by 10% as compared with the process without SRHA. Similarly, at concentrations of 50 ppm of SRHA, the Zn removal efficiency decreased by 20% as compared with the process without SRHA. However, our study refutes the view that the accumulation of NOM on mine tailings could possibly reduce the process efficiency. We conclude that the suspended NOM was able to alter the process efficiency by reducing the bacterial attachment on the mine tailing's surface, which suggested the importance of the bacterial contact mechanism.