Chemoorganotrophic Bioleaching of Olivine for Nickel Recovery

Abstract

Bioleaching of olivine, a natural nickel-containing magnesium-iron-silicate, was conducted by applying chemoorganotrophic bacteria and fungi. The tested fungus, Aspergillus niger, leached substantially more nickel from olivine than the tested bacterium, Paenibacillus mucilaginosus. Aspergillus niger also outperformed two other fungal species: Humicola grisae and Penicillium chrysogenum. Contrary to traditional acid leaching, the microorganisms leached nickel preferentially over magnesium and iron. An average selectivity factor of 2.2 was achieved for nickel compared to iron. The impact of ultrasonic conditioning on bioleaching was also tested, and it was found to substantially increase nickel extraction by A. niger. This is credited to an enhancement in the fungal growth rate, to the promotion of particle degradation, and to the detachment of the stagnant biofilm around the particles. Furthermore, ultrasonic conditioning enhanced the selectivity of A. niger for nickel over iron to a value of 3.5. Pre-carbonating the olivine mineral, to OPEN ACCESSMinerals 2014, 4 554 enhance mineral liberation and change metal speciation, was also attempted, but did not result in improvement as a consequence of the mild pH of chemoorganotrophic bioleaching.

A Review of the Application of Ultrasound in Bioleaching and Insights from Sonication in (Bio)Chemical Processes

“…Unfortunately, the impact of ultrasound was examined only on the fungal bioleaching of olivine (i.e., bacterial sonobioleaching was not examined). On sonication, an increase from 9.9% to 15.7% was observed in Ni leaching over 17 days [99]. Other metals present in the ore (such as Mg, Al, Si and Cr) increased marginally.…”

“…In sonobioleaching, ultrasound can be applied during the growth of the microorganism and/or leaching (Table 1) [96,99]. When applied during growth, low intensity should be used, since positive effects on bacterial growth have been observed [60,80].…”

CO2 Energy Reactor – Integrated Mineral Carbonation: Perspectives on Lab-Scale Investigation and Products Valorization

“…Another opportunity is the recovery of metallic components (primarily nickel and chromium) from carbonated olivine. Santos et al (2015b) and Chiang et al (2014) have reported on nickel extraction efforts from carbonated olivine using chemical and biological means, respectively. It has been found that at elevated acidity, more nickel can be extracted from carbonated olivine compared to fresh olivine.…”

Nickel Extraction from Olivine: Effect of Carbonation Pre-Treatment

“…A preliminary test was performed using a large variety of organic acids: citric acid (HOC(COOH)(CH2COOH)2), oxalic acid (HOOCCOOH), succinic acid (HOOC(CH2)2COOH), lactic acid (CH3CH(OH)COOH), acetic acid (CH3COOH), formic acid (HCOOH) and butyric acid (C3H7COOH). These organic acids were chosen as they are reportedly produced by microorganisms utilized in bioleaching of silicate minerals [21,22]. Based on preliminary experimental results ( Figure S5) the three most promising organic acids, citric acid, formic acid, and lactic acid were selected for further use in the experiments discussed hereon.…”