Bio-oxidation of ferrous iron at low temperature conditions in a packed bed column bioreactors

Abstract

The oxidation of microbial ferrous iron is an important sub-process in the bioleaching process. Several studies focussing on microbial ferrous iron oxidation have been investigated and reported in various studies. These studies were carried out using stirred tank bioreactors and shake flasks at optimum conditions. However, these studies could not describe the context of heap bioleach system. Packed column system may describe heap bioleaching, and most studies on microbial ferrous iron oxidation were performed under flooded conditions, which do not represent solution flow dynamics in a heap situation. Biooxidation of ferrous iron oxidation kinetics of Acidiobacillus ferrooxidans was studied in a packed-bed bioreactor to investigate the kinetics in a system that mimics the solution flow dynamic of a heap bioleach operation at low-temperature conditions. This was done in a batch mode operation, with glass marble (15 mm) as reactor packing. The pH of the bioreactor was maintained at pH 1.35 ± 0.05 and aeration at 500 ml/min. Unstructured models known as Monod and Hansford were used to describe the experimental data in determining the kinetics of bio-oxidation.