Table 1.
The main characteristics of ore sample used in the study a.
Fig 1.
The experimental setup of the different bioleaching procedures designed for this study: A. caldus blank control system (BC); A. caldus planktonic cells-deficient system (PD); A. caldus attached cells-deficient system (AD); A. caldus EPS /attached cells-deficient system (ED).
Fig 2.
Changes in key chemical parameters in different deficient bioleaching systems.
(A): pH; (B): Eh; (C): Sulfate ions; (D): Ferrous ions; (E): Ferric ions; (F) Planktonic and attached biomass; (G) μx of planktonic and attached cells. Note: the pH of leachate during bioleaching was measured before the pH-1.5 adjustment by 6 M HCl every two days.
Table 2.
Comparison of key chemical and biological parameters between pre-leaching and after-leaching in BC, PD, ED and AD systems.
Fig 3.
Morphological surface differences of the ore samples between the different bioleaching systems: (A): BC; (B): PD; (C): AD; (D) ED. The slag was dried at room temperature in a vacuum desiccator and observed via scanning electron microscopy at 10× k magnification (bar, 5 μm, 10× k).
Fig 4.
XRD analysis of the ore samples in different bioleaching systems.
C:CuFeS2; S:Sulfur; H: Fe2O3; I: Fe(OH)3; K: Fe3(SO4) 4; R: FeSO44; J: KFe3(SO4)2(OH)6; M: H: Fe3O4.
Fig 5.
FTIR analysis of the ore samples in the different deficient bioleaching systems.
Fig 6.
Changes in copper ions in different systems and relative bioleaching efficiencies of different mechanisms.
(A): Copper ion; (B): Relative bioleaching efficiencies of different mechanisms.
Fig 7.
Overview of the specific function of the “EPS-mediated contact” mechanism in the bioleaching of copper-bearing sulfide ore by the moderately thermophilic Acidithiobacillus caldus.
Table 3.
Comparison between our study and other previous related literatures.