1926 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Microstructure Evolution
The microstructure of reduction products at different reduc-
tion temperatures was measured to study their phase trans-
formation by SEM–EDS as shown in Figure 11 and 12.
Figure 11 indicates that the particles are presented in
the oolitic structure along with a large number of cracks.
As the reduction temperature increased from 460 °C to
540 °C, the cracks and fissures grew along the interface
of iron minerals and gangue by the phase transformation,
confirming the transformation of hematite into magne-
tite as determined by VSM and XRD. These microcracks
provide a pathway for reductant to enter the center of the
oolite structure and further react with the hematite inside.
With the increase in reduction temperature from 540 °C
to 600 °C, the cracks and fissures continuously deepened
toward the core, leading to the destruction of the oolitic
structure (Bingbing, L., et al., 2021). This occurred due
to a significant mismatch in the thermal expansion coeffi-
cients of the hematite and magnetite during minerals phase
transformation.
EDS spectra of reduction products at different reduc-
tion temperatures was determine, as shown in Figure 12,
As found in Table 3, the elemental composition of point
1 and 2 consists mainly of iron (Fe) and oxygen (O), with
relative element mass of 1.41 and 1.53 in the range of 0
to 2.33, indicating that the main component in the form
of hematite. Moreover, the element mass of point 5 and
6 at the reduction temperature of 540 °C were 2.36 and
2.56 in the range of 2.33 to 2.65, determining that the
main component was magnetite (Siwei, L., et al., 2021).
As the reduction temperature exceeded 540 °C, the ele-
ment mass of point 7 and 8 was 2.57 and 2.91, indicating
Figure 10. XPS survey spectra of raw ore (a) and reduction product (b) The Fe2p spectra of raw ore (c) and reduction product (d)
Microstructure Evolution
The microstructure of reduction products at different reduc-
tion temperatures was measured to study their phase trans-
formation by SEM–EDS as shown in Figure 11 and 12.
Figure 11 indicates that the particles are presented in
the oolitic structure along with a large number of cracks.
As the reduction temperature increased from 460 °C to
540 °C, the cracks and fissures grew along the interface
of iron minerals and gangue by the phase transformation,
confirming the transformation of hematite into magne-
tite as determined by VSM and XRD. These microcracks
provide a pathway for reductant to enter the center of the
oolite structure and further react with the hematite inside.
With the increase in reduction temperature from 540 °C
to 600 °C, the cracks and fissures continuously deepened
toward the core, leading to the destruction of the oolitic
structure (Bingbing, L., et al., 2021). This occurred due
to a significant mismatch in the thermal expansion coeffi-
cients of the hematite and magnetite during minerals phase
transformation.
EDS spectra of reduction products at different reduc-
tion temperatures was determine, as shown in Figure 12,
As found in Table 3, the elemental composition of point
1 and 2 consists mainly of iron (Fe) and oxygen (O), with
relative element mass of 1.41 and 1.53 in the range of 0
to 2.33, indicating that the main component in the form
of hematite. Moreover, the element mass of point 5 and
6 at the reduction temperature of 540 °C were 2.36 and
2.56 in the range of 2.33 to 2.65, determining that the
main component was magnetite (Siwei, L., et al., 2021).
As the reduction temperature exceeded 540 °C, the ele-
ment mass of point 7 and 8 was 2.57 and 2.91, indicating
Figure 10. XPS survey spectra of raw ore (a) and reduction product (b) The Fe2p spectra of raw ore (c) and reduction product (d)