Abstract
Biohydrometallurgy is believed to be a promising future study field for the recovery of lead (Pb) from ores/concentrates since the pyrometallurgical/hydrometallurgical processes have been largely applied to recover Pb to date, which operates at high temperature and generates volatile Pb matters that are hazardous and carcinogenic to human health. Hence, the main purpose of this study was to investigate the biohydrometallurgical extraction of Pb from the Indonesian galena concentrate through bioleaching using an iron- and sulfur-oxidizing mixotrophic bacterium (identified as Citrobacter sp.). The bioleaching experiments were conducted in shake flasks containing the modified LB broth medium supplemented with galena concentrate with a particle size of d80 = 75 μm at room temperature. Both semi-direct and direct bioleaching methods were employed in this study. The bacterium was able to extract lead (Pb) from galena concentrate with high selectivity to Cu and Zn (0.99 and 0.86, respectively). The highest extraction level of 90 g lead dissolved/kg galena concentrate was achieved using direct bioleaching method at bioleaching conditions of 2% w/v pulp density, 5 g/L FeCl3, 50 g/L NaCl, 20 g/L molasses and a rotation speed of 180 rpm at room temperature (25°C). The addition of FeCl3, NaCl, and molasses increased the lead leaching efficiencies, which were also evidenced by the FTIR, XRD, and SEM-EDS analyses. From industrial and commercial standpoints, the selective bioleaching represented in this study may be beneficial to the development of lead leaching from sulfide minerals, since insoluble anglesite (PbSO4) precipitates are formed during ferric sulfate oxidation, thus making the recovery of lead through bioleaching unpractical.
Highlights
The extraction of lead (Pb) from sulfide ores relies on pyrometallurgical smelting processes and combined pyro/hydrometallurgical methods that are the high energy consumption and cause severe environmental pollution problems due to the emission of both SO2 and volatile lead matters
The bioleaching of galena (PbS) has been poorly studied, since the complete oxidation of galena leads to insoluble anglesite (PbSO4) that precludes the recovery of lead from bioleaching and ferric sulfate leaching through conventional solvent extraction/electrowinning routes (Da Silva et al, 2003; Da Silva, 2004)
Semi-direct bioleaching experiments were conducted by adding various concentrations of FeCl3 (5 and 25 g/L), NaCl (30 and 50 g/L) and molasses (10, 20, and 30 g/L) at 5% w/v pulp density to evaluate their effects on lead recovery
Summary
The extraction of lead (Pb) from sulfide ores relies on pyrometallurgical smelting processes and combined pyro/hydrometallurgical methods that are the high energy consumption and cause severe environmental pollution problems due to the emission of both SO2 and volatile lead matters. Bioleaching of lead concentrates as a biohydrometallurgical method has emerged as a possible solution for overcoming the aforementioned problems since the bioleaching is a low-cost, environmentally friendly method. The bioleaching of galena (PbS) has been poorly studied, since the complete oxidation of galena leads to insoluble anglesite (PbSO4) that precludes the recovery of lead from bioleaching and ferric sulfate leaching through conventional solvent extraction/electrowinning routes (Da Silva et al, 2003; Da Silva, 2004). Several studies demonstrated that the elevated lead bioleaching/leaching efficiencies were achieved
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
