A Comparative Study on Bioleaching Properties of Various Sulfide Minerals Using Acidiphilium cryptum

Abstract

Bioleaching has been regarded as a green alternative to chemical leaching in metal extraction processes. In this study, the bioleaching properties of indigenous acidophilic bacteria for various sulfide minerals were compared and evaluated in terms of pH reduction and metal leaching. The primary minerals in the samples were sphalerite (ZnS) (SP), galena (PbS) (GN1 and GN2), pyrite (FeS2) (PY), and chalcopyrite (CuFeS2) (CCP), and an indigenous acidophilic bacterium, Acidiphilium cryptum (99.56%), was applied for bioleaching experiments. The metal extraction in bioleaching differed according to the mineral content. The leached metal concentration of Zn was higher than that of Pb for the SP sample with a high ZnS content, whereas the concentration of Pb was higher than that of Zn for the GN1 and GN2 samples with a high PbS content. Meanwhile, the leaching rate of Zn was faster than that of Pb for all samples. Corrosion action was observed on the surface of bacterial residues in SP and GN1 samples. These results show that the bioleaching mechanism based on sulfide minerals proceeds through indirect biological oxidation, chemical oxidation, and direct bacterial oxidation. The results of this study can provide basic research data for process optimization when employing bioleaching to extract valuable metals.

Acidophilic heterotrophs: basic aspects and technological applications

“…The action mechanism of iron reducers has been explained due to interactions with the solid compounds and other strains (i.e., iron-and sulfur-oxidizers) (Johnson and Roberto, 1997;10.3389/fmicb.2024.1374800 Frontiers in Microbiology 04 frontiersin.org Liu et al, 2011). Nevertheless, the ability of some heterotrophs to oxidize Fe(II) and sulfur-reduced compounds may also be relevant (Bacelar-Nicolau and Johnson, 1999;Priya and Hait, 2018;Bulaev, 2020;Panyushkina et al, 2021Panyushkina et al, , 2022Enuh and Aytar Çelik, 2022;Cho et al, 2023).…”

Use of Bayesian Methods in the Process of Uranium Bioleaching by Acidithiobacillus ferrooxidans

“…The increase in world demand for mineral goods, combined with the progressive depletion of reserves containing high levels of metals of economic interest and the need to guarantee nuclear fuel for the continuous operation of nuclear power plants in energy production, makes it important to develop alternatives for the treatment of ores containing low levels of these metals, such as uranium [1]. Bioleaching is a green technology for extracting, concentrating, or recovering metals from ores or waste, being an environmentally sustainable alternative to conventional hydrometallurgical processes [2][3][4].…”