title: Bioleaching of nickel and cobalt from lateritic chromite overburden using the culture filtrate of Aspergillus niger.
abstract: Extraction of metals (Ni, Co) from chromite overburden of Sukinda mines of Orissa, India, with the culture filtrate of Aspergillus niger was studied. Results showed that the amounts of metals leached varied directly with reaction temperature and period of fermentation. The culture filtrate was analyzed for citric and oxalic acids, and contained only oxalic acid-the concentration of which increased with time. Although this acid played the major role in leaching of metals, other unidentified metabolites present in the culture filtrate influenced the dissolution of the metals significantly. Maximum recovery of metals from raw and roasted ore samples was achieved at 80 °C with the 21-day culture filtrate containing the highest amount of oxalic acid. Under identical experimental conditions, much higher amounts of the metals were leached from roasted ore. Microstructures of the ore particles were studied by scanning electron microscopy and transmission electron microscopy; the bonding behaviors of metal compounds were identified by Fourier transform infrared spectroscopy which showed that the metals were leached after chelation with oxalic acid.
authors.affiliation: Department of Metallurgical and Material Engineering, Jadavpur University, Kolkata 700032, India. supratimbiswas07@gmail.com
authors.forename: Supratim
authors.initials: S
authors.lastname: Biswas
authors.forename: Rajib
authors.initials: R
authors.lastname: Dey
authors.forename: Siddhartha
authors.initials: S
authors.lastname: Mukherjee
authors.forename: Pataki C
authors.initials: PC
authors.lastname: Banerjee
mesh_terms: D001234:Aspergillus niger / Q000737:chemistry* / Q000302:isolation & purification; D002474:Cell-Free System / Q000737:chemistry; D002857:Chromium / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry* / Q000302:isolation & purification*; D003470:Culture Media / Q000737:chemistry; D008906:Mining / Q000379:methods; D009532:Nickel / Q000737:chemistry* / Q000302:isolation & purification*; D012987:Soil / Q000737:chemistry*
chemical_list: D003470:Culture Media; D012987:Soil; D002857:Chromium; D003035:Cobalt; D009532:Nickel