1848 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
of dense iron might wrap the iron oxides, which was not
conducive to the continuation of the reduction reaction
Combining the X-ray diffraction (XRD) and labora-
tory results of the reduction products, SEM images at
different time revealed that, over time, hematite likely
underwent a transformation from hematite to magnetite,
then transitioned into wüstite, ultimately converting into
metallic iron. From Figure 10a, it could be observed that
the iron minerals within the nucleus exhibited a needle-
like structure, similar to the morphology of unreacted
magnetite observed in the reduction products at 600 and
700°C, indicating the presence of unreduced magnetite in
the nucleus at this stage. As the reaction time extended to
10 minutes, metallic iron started to form in the periph-
ery of the ore and around pores, wrapping the coarsening
needle-like magnetite (Figure 10b). After 15 minutes, there
was widespread generation of metallic iron (Figure 10c).
However, from the energy spectrum (Figure 10f), it could
be seen that there were still a small number of diffraction
peaks of oxygen and silicon, etc. Combined with the XRD
analysis, it was possible that substances such as fayalite gen-
erated and covered by metallic iron, making it difficult to
continue the reduction.
HYDROGEN BASED SUSPENSION
ROASTING MODEL OF OOLITIC
HEMATITE
To enhance the comprehension of the phase transition
and microstructural evolution of oolitic hematite during
the entire reduction process, a model for hydrogen-based
suspension roasting reduction of oolitic hematite was pro-
posed, as depicted in the Figure 11. In the initial stage of
Figure 9. Cross-section SEM images of roasted samples at different reduction temperatures: (a) 600 °C (b) 700 °C (c), (d)
800 °C (e), (f) 900 °C, (g), (h), (i) EDS results (figure continues)
of dense iron might wrap the iron oxides, which was not
conducive to the continuation of the reduction reaction
Combining the X-ray diffraction (XRD) and labora-
tory results of the reduction products, SEM images at
different time revealed that, over time, hematite likely
underwent a transformation from hematite to magnetite,
then transitioned into wüstite, ultimately converting into
metallic iron. From Figure 10a, it could be observed that
the iron minerals within the nucleus exhibited a needle-
like structure, similar to the morphology of unreacted
magnetite observed in the reduction products at 600 and
700°C, indicating the presence of unreduced magnetite in
the nucleus at this stage. As the reaction time extended to
10 minutes, metallic iron started to form in the periph-
ery of the ore and around pores, wrapping the coarsening
needle-like magnetite (Figure 10b). After 15 minutes, there
was widespread generation of metallic iron (Figure 10c).
However, from the energy spectrum (Figure 10f), it could
be seen that there were still a small number of diffraction
peaks of oxygen and silicon, etc. Combined with the XRD
analysis, it was possible that substances such as fayalite gen-
erated and covered by metallic iron, making it difficult to
continue the reduction.
HYDROGEN BASED SUSPENSION
ROASTING MODEL OF OOLITIC
HEMATITE
To enhance the comprehension of the phase transition
and microstructural evolution of oolitic hematite during
the entire reduction process, a model for hydrogen-based
suspension roasting reduction of oolitic hematite was pro-
posed, as depicted in the Figure 11. In the initial stage of
Figure 9. Cross-section SEM images of roasted samples at different reduction temperatures: (a) 600 °C (b) 700 °C (c), (d)
800 °C (e), (f) 900 °C, (g), (h), (i) EDS results (figure continues)