4
microbial activity increased as fresh nutrient media in the
form of organic compounds was supplied to iron-reducing
organisms. Further increases in the dissolved iron concen-
tration were observed, reaching around 400 mg/L. The pH
for hematite tailings leaching was observed in the range of
4.3 to 5.94, and 29% of the iron present was dissolved in
368 days. The comparison of total iron dissolved by organ-
isms in 368 days is shown in Figure 7.
As reductive bioleaching is more effective on hydrated
iron oxides such as goethite, higher dissolved iron concen-
trations in Source A (Goethite tailings) compared to Source
B (Hematite tailings) were observed. Hematite has a crystal-
line structure, making it more resistant to microbial attack,
and it gives less iron dissolution compared to goethite.
Further, the higher dissolved iron concentrations
observed in Source A to Source B can also be attributed to
the particle size differences between the two sources. The
finer particle size in Source A provides a larger surface area,
enhancing microbial accessibility and facilitating more
effective bioleaching.
The ore residue was analyzed using X-ray diffraction.
Preliminary findings revealed that goethite was primarily
Figure 5. Graph showing the dissolved iron concentration in bioleaching experiments on the
tailings collected from source A, where goethite was the dominant form of iron oxide
Figure 4. Experimental setup for iron leaching by iron-reducing organisms and T. latifolia
microbial activity increased as fresh nutrient media in the
form of organic compounds was supplied to iron-reducing
organisms. Further increases in the dissolved iron concen-
tration were observed, reaching around 400 mg/L. The pH
for hematite tailings leaching was observed in the range of
4.3 to 5.94, and 29% of the iron present was dissolved in
368 days. The comparison of total iron dissolved by organ-
isms in 368 days is shown in Figure 7.
As reductive bioleaching is more effective on hydrated
iron oxides such as goethite, higher dissolved iron concen-
trations in Source A (Goethite tailings) compared to Source
B (Hematite tailings) were observed. Hematite has a crystal-
line structure, making it more resistant to microbial attack,
and it gives less iron dissolution compared to goethite.
Further, the higher dissolved iron concentrations
observed in Source A to Source B can also be attributed to
the particle size differences between the two sources. The
finer particle size in Source A provides a larger surface area,
enhancing microbial accessibility and facilitating more
effective bioleaching.
The ore residue was analyzed using X-ray diffraction.
Preliminary findings revealed that goethite was primarily
Figure 5. Graph showing the dissolved iron concentration in bioleaching experiments on the
tailings collected from source A, where goethite was the dominant form of iron oxide
Figure 4. Experimental setup for iron leaching by iron-reducing organisms and T. latifolia