Simultaneous lithium bioleaching and bioaccumulation from lepidolite using microscopic fungus Aspergillus niger

Abstract

The leaching of lithium from lepidolite using the filamentous fungus Aspergilluss niger was examined. Two mechanisms were suggested – biochemical using citric acid as the main bioleaching agent and biomechanical through hyphae penetration confirmed by XRD and SEM analyses. The bioleaching processes were conducted at various glucose concentrations (5 – 20 g.L-1). The higher glucose concentration was, the higher Li bioleaching was observed. Li accumulation by fungal biomass played an important role in Li solubilisation from lepidolite. Totally, 11.5 mg of lithium were recovered from 1 kg of lepidolite by combination of bioleaching and bioaccumulation processes. As a result of bioleaching, the formation of new silicate phase of SiO2 was detected. According to the results, fungal bioleaching of Li from lepidolite can be a perspective way of Li recovery from hard-rock ores.

Beneficiation of a Nigerian lepidolite ore by sulfuric acid leaching

“…With the same view, Gu et al (2020) used medium-low temperature activation roasting and sulphuric acid leaching to achieve a maximum lithium leaching rate of 86.23%. The bioleaching procedure summarised by Sedlakova-Kadukova et al ( 2020), Marcinčáková et al (2015aMarcinčáková et al ( , 2015b and Rezza et al (1997) has little or no significant leaching efficiency due to low sulphur affinity in the ore. Some of the techniques aiming at obtaining highgrade lithium/lithium compounds have not been reported on Nigerian-sourced lithium ore varieties.…”