BIOLIXIVIAÇÃO DE MINÉRIOS DE COBRE EM REATORES COM ACIDITHIOBACILLUS FERROOXIDANS

Abstract

Bioleaching consists of ore leaching by the action of iron and sulfur oxidizing bacteria, such as Acidithiobacillus ferrooxidans. This study aimed to evaluate the bioleaching process of sulfide and weathered copper ores, from the Serra dos Carajás (PA), in Brazil. An assay was conduct in batch, in stirred tanks inoculated with A. ferrooxidans, during 100 days. Samples mineralogical and chemical characterizations were performed by X-ray Diffraction (XRD) and Energy Dispersive X-ray Fluorescence (EDXRF), respectively. Measurement of pH and redox potential (Eh) were performed daily, and samples collected for copper extraction determination (EDXRF). The results highlighted the similar behavior of Eh and distinguished to pH, due to different ores composition. On the 100th day, the sulfide ore sample presented 0.74% copper extraction, but the process being still active. The weathered ore sample presented 18.35% of extraction on the 60th day and the process ended on the 100th day. The stirred reactors bioleaching process may be a viable alternative for copper recovery meanly from weathered copper ores.