Study on reaction mechanism of bioleaching of nickel and cobalt from lateritic chromite overburdens

摘要: Abstract Depletion of high-grade ores and presence significant quantities metals in low-grade oxide has enforced to utilize the overburdens (COB) wastes (low-grade ores) generated during mining operations. The impact ore mineralogy mineral–microbe interaction bioleaching could not be ignored. Seeking need, a systematic study was performed establish reaction mechanism involved for recovery nickel cobalt from chromite overburden (COB), Sukinda, Orissa using pure culture Aspergillus niger. Mineralogical analysis reveals complete conversion goethite into hematite phase leading exposure particles micro-pores cracks developed matrix which initially found intertwined lattice. As result, it became more susceptible attack by fungal bio acids turn accelerate dissolution rate. Organic like oxalic citric were detected filtrate HPLC. TEM leached samples shows that dissolute solution leaving porous space forming oxalate or citrate. Kinetics studied support reaction. It observed initial rate follows chemical control where as later part fits shrinking core model. 18% 37.8% recovered pre-treated COB at 2.5% pulp-density with 10% (v/v) inoculum 30 °C within 25 days shake flask while 32.5% 86% bioreactor.