Characterization and bioleaching of nickel laterite ore using Bacillus subtilis strain

Le résumé fourni par la source

Abstract There are two principal types of nickel (Ni) deposits: sulfide and laterite ores. Interest in low‐grade Ni‐laterite ores has increased in recent years as high‐grade Ni‐sulfide deposits are being quickly depleted. However, processing of Ni laterites has proven technically difficult and costly, and the development of alternative low‐cost biotechnologies for Ni solubilization has been encouraged. In this context, by the first time, a sample of Brazilian Ni‐laterite ore was analyzed mineralogically and subjected to bioleaching tests using a heterotrophic Bacillus subtilis strain. SEM‐analysis indicated that the primary Ni carrier mineral is goethite. Chemical analysis of different grain size fractions indicated a homogeneous distribution of Ni. XRF‐analysis showed that the ore consists mainly in lizardite (32.6% MgO) and contains1.0% NiO (0.85% Ni). Bioleaching batch experiments demonstrated that about 8.1% Ni (0.7 mg Ni/g ore) were solubilized by the B. subtilis after 7 days. Application of microwave heating as a Ni‐laterite pretreatment was also tested. This pretreatment increased the bioextraction of Ni from 8% to 26% (2.3 mg Ni g −1 ore).

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