Acidithiobacillus ferrooxidans and mixed Acidophilic microbiota oxidation to remove sulphur impurity from iron concentrate

Abstract

This study reports the bacterial properties of mixed Acidophilic microbiota with sulfur as electron donor and Acidithiobacillus ferrooxidans (A. ferrooxidans) with FeS2 as electron donor and conducted microbial desulfurization experiments. The results showed that mixed Acidophilic microbiota and A.ferrooxidans could effectively reduce the sulfur content in iron concentrate, with the desulfurization efficiency of 79.8 % and 45.7 % in 30 days. And the recovery rates were above 90 % and 88 % respectively. The results of the Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS) showed that both bacteria oxidized the iron concentrate and removed the sulfur-containing impurity from the surface of the ore sample. According to the enrichment of elemental phosphorus on the sulfur of the ore sample, it can be deduced that the bacteria were oxidized. After the leaching of A.ferrooxidans, it was found that jarosite was generated, which was consistent with the conclusion of Stereomicroscope morphological observation. Based on X-ray photoelectron spectroscopy analysis, it was concluded that mixed Acidophilic microbiota could reduce the deposition on the surface of iron concentrate after the leaching of sulfate and improve the bioleaching efficiency. The conversion route of sulfur was identified to be from S2-/S22- to Sn2-/S0, and finally SO42-. In conclusion, a model for the oxidation of iron concentrate by A.ferrooxidans and Mixed Acidophilic Microbiota during bioleaching has been proposed.