The mechanism of leaching chalcopyrite by Acidithiobacillus ferrooxidans （,4. ferrooxidans） in agar-simulated extracellular polymeric substances （EPS） media was investigated. The results indicate that bacterial EPS can release H＋ and concentrate Fe3＋; Fe2＋ is movable between agar-simulated EPS phase and bulk solution phase, but it is difficult for Fe3＋ to move due to its hydroxylation and EPS complex action; A. ferrooxidans first prefer Fe2＋ as energy to metabolize compared with chalcopyrite, and a suitable simulated EPS environment for bacterial living is at about pH 1.8; the iron precipitates and jarosites formed by a lot of biologically oxidized Fe3 cover the simulated EPS easily and form an impermeable deposit acting as a limited barrier of ion transport that attenuates the aggressiveness of the bioleaching attack. The EPS layer blocked by iron precipitates or jarosites is responsible for the chalcopyrite passivation.
This work aims to describe the history of biometallurgy in China,introduce the development and application of biometallurgy technologies in exploitation of mineral resources,and identify the main challenges and future directions.Although the earliest biometallurgy activities in China were documented in 6th−7th century BC,fundamental research and biometallurgy applications started relatively late in this country.Rapid development,from phenotypic to genotypic characterization of biometallurgy microorganisms,as well as from theoretical to practical applications,has been made in China since the 1950s.The integrated applications of biometallurgy technology in copper,gold,and uranium extraction ensured China’s economic reserves of strategic mineral resources.Developing more efficient microorganisms and strengthening the micro-interface reactions will be an effective way to improve the biometallurgy efficiency.Biometallurgy technologies can also be adapted to recovery of valuable metal from marine minerals and e-wastes and environmental protection including carbon sequestration and heavy metal polluted soil/sediment bioremediation.
