National University of Colombia, Colombia
Laura Muñoz has completed her bachelor degree in Biological Engineering from National University of Colombia, and currently pursuing a master degree in Science-Biotechnology at the same University. She is a researcher of Bioprocess and Applied Mineralogy Group (GMAB) and Symbiotic System (SS).
In Colombia, tons of mine tailings are generate daily with gold or another precious metals unrecovered by traditional methods. Previous studies have shown that biooxidation, little know it in the country, are an economical and environmentally accepted pretreatment. This bioprocess can increase the efficiency extraction and is useful exploiting secondary sources of metals. The aim of this work was scale-up the biooxidation process of mine tailings, from laboratory to pilot plant. Flasks, stirred tank bioreactors, tailings from La Marujamine (Caldas, Colombia) and Acidithiobacillus ferrooxidans as a biological agent were used. All assays were carried out for ten days and monitored by chemical measurements of iron, sulfates, pH and redox potential. To scale-up was taken into account parameters previously evaluated. The results in 250millitersflasks and 5 liters bioreactor were similar in all response variables, particularly in the iron removed percentage. The iron removed was increase 9% in the 50 liters reactor. Otherwise, in the 4000 liters reactor (pilot scale) final concentration of iron removed was similar to 5 liters assays, however, the oxidation rates were slower at the beginning. The percentage of gold recovered was higher in assays in larger reactors. These results suggested that the scale-up was successful about the gold recovered, but there are conditions to be controller at pilot level to improve the oxidation kinetics.