Mechanism for the Bio-Oxidation and Decomposition of Pentlandite: Implication for Nickel Bioleaching at Elevated pH

Abstract

This work investigated the effects of Fe3+, H+ and adsorbed leaching bacteria on the bioleaching of pentlandite. Collectively, an integrated model for the oxidation and decomposition of pentlandite was built to describe the behaviors of different components in a bioleaching system. Proton ions and ferric ions could promote the break and oxidation of Ni-S and Fe-S bonds. The iron-oxidizing microorganisms could regenerate ferric ions and maintain a high Eh value. The sulfur-oxidizing microorganisms showed significant importance in the oxidation of polysulfide and elemental sulfur. The atoms in pentlandite show different modification pathways during the bioleaching process: iron transformed through a (Ni,Fe)9S8 → Fe2+ → Fe3+ → KFe3(SO4)2(OH)6 pathway; nickel experienced a transformation of (Ni,Fe)9S8 → NiS → Ni2+; sulfur modified through the pathway of S2−/S22− → Sn2− → S0 → SO32− → SO42−. During bioleaching, a sulfur-rich layer and jarosite layer formed on the mineral surface, and the rise of pH value accelerated the process. However, no evidence for the inhibition of the layers was shown in the bioleaching of pentlandite at pH 3.00. This study provides a novel method for the extraction of nickel from pentlandite by bioleaching at elevated pH values.

Comparison of Bio- and Ferric Leaching for Beneficiation of Bulk Copper-Nickel Sulfidic Concentrate

“…Thus, nickel recovery may be increased with an increase in the duration of bioleaching. Similarly, no inhibition of nickel bioleaching from the nickel concentrate has been reported by Sun et al [22]. The microbial community showed high iron-oxidizing activity, resulting in the rapid oxidation of ferrous iron in the medium within the first 4-5 days of the bioprocess (Figure 3b).…”

Processing of Alluvial Deposit Sands with a High Content of Copper and Nickel Using Combined Enrichment Technology

“…The active development of various biohydrometallurgical approaches continues, with the use of microorganisms having been suggested for the extraction of metals from various mineral and secondary raw materials, making it possible to further develop the field of biohydrometallurgy and increase its practical significance. This work is aimed at creating new biohydrometallurgical technologies based on the use of already-known approaches for use in the processing of new types of raw material, such as ores and concentrates containing platinum-group metals, as well as the development of new principles whereby various groups of microorganisms are used that are not currently involved in biohydrometallurgical processes, but which are capable of transforming various minerals, as well as interacting with metals, such as, for example, the use of heterotrophic bacteria and fungi for the processing of gold-bearing ores, double refractory concentrates or ores containing rare earth elements, as well as the use of neutrophilic and moderately acidophilic microorganisms in the processes of biooxidation of sulfide ores and concentrates [6,8,10,[15][16][17][18][19][20][21].…”

Editorial on Special Issue “Surface Chemistry in Mineral Processing and Extractive Metallurgy”

“…Fundamental forces between bioleaching bacterium and mineral surfaces are the central point to understand the intricacies of interfacial phenomenon, like bacterial adhesion or metal detachment from mineral surface followed by dissolution of metal in ionic form [15]. More precisely, it uses a catalytic effect produced by metabolic activity of the microorganisms [18]. On the other side, the adhesion behavior of a bacterial cell surface in the aqueous environment is mediated by various physicochemical intersections including van der Wall forces, electrostatic interaction, steric forces, hydration, and hydrophobic interactions [19].…”