The use of biotechnology to explore low-grade ore deposits and mining tailings is one of the most promising alternatives to reduce environmental impacts and costs of copper extraction. However, such technology still depends on improvements to be fully applied in Brazil under industrial scale. In this way, the bioleaching, by Acidithiobacillus ferrooxidans, in columns and stirred reactors were evaluated regarding to copper extraction of a mineral sulfide and a weathered ore from the Brazilian Amazon region. Samples (granulometry of 2.0/4.75 mm) were characterized by X-ray diffraction (XRD), energy dispersive X-ray fluorescence (EDXRF) spectrometry and scanning electrons microscopy (SEM). The pH and Oxidation-reduction potential (Eh) were daily monitored and leachate samples were collected for copper extraction determination by EDXRF. After 47 days, the columns bioleaching efficiency was 1% (1298 mg Cu·L−1) and 0.95% (985 mg Cu·L−1) for 2.00/4.75 mm sulfide ore, respectively, whereas the stirred reactors bioleaching resulted in 4% (348 mg Cu·L−1) for the mineral sulfide and 47% (295.5 mg Cu·L−1) for the weathered ore.

Steel production generates dust containing Zn and Fe that can be recovered under certain conditions. The main objectives of the study were to evaluate the recovery of these elements when added in briquette form to liquid pig iron at a temperature of 1500°C and to chemically and morphologically characterize the Electric Arc Furnace Dust (EAFD). In the dust characterization stage, the following techniques were used: granulometric and chemical analyses, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), and X-ray Diffraction (XRD). After characterization, the dust was agglomerated in order to form a briquette, then, placed in liquid pig iron. To perform the tests, a vertical laboratory-scale furnace was used that maintained an inert gas flow (argon) within the furnace during the experiments. All melting tests were performed in this device. Alumina crucibles were used. The zinc was reduced, volatilized and collected by a flue placed on top of the furnace. It was possible to achieve FeO reduction values higher than 98%. The new dust collected during the tests contained iron and 68% of zinc on the average.