Removal of iron impurities from refractory gold ore using Acidithiobacillus Ferrooxidans

Acidithiobacillus ferrooxidans is a chemolithoautotrophic bacterium capable of deriving energy from oxidizing ferrous iron to ferric iron, utilizing molecular oxygen as an electron acceptor. This process, known as iron oxidation, holds significance in both extracting metals from ore minerals and in the biogeochemical cycling of sulfur and iron in the environment. Microbial leaching, employing iron-oxidizing bacteria like A. ferrooxidans, presents a sustainable approach to reducing excessive heavy metals, such as iron (Fe), in ore minerals, thus contributing to ecosystem preservation. Traditional methods of heavy metal removal often rely on costly physical and chemical processes, posing risks to human health due to exposure to toxic chemicals like cyanide, which can lead to cyanide poisoning by inhibiting essential cellular functions. In this research, the objective is to characterize the composition of refractory gold ore and explore Fe removal from it using A. ferrooxidans through bioleaching, evaluating its impact on gold concentration post-process. Initially, the refractory gold ore sample's composition was analyzed via X-ray fluorescence (XRF). Subsequently, the ore sample will be subjected to a 20-day bioleaching process in a medium inoculated with the microbe. After this period, Acidithiobacillus ferrooxidans had successfully reduced Fe(III) to Fe(II), resulting in an increase in gold purity. Analysis using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) revealed a rise in gold concentrations from 2.009 ppm to 2.231 ppm, indicating an 11.05% increase in gold recovery. In conclusion, A. ferrooxidans effectively reduced Fe content in the ore sample through microbial leaching, demonstrating its potential for sustainable metal extraction processes.