1326 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
certain minerals in the ore are decomposed and bound water
is removed, facilitating the subsequent reduction reaction.
The heated sample then enters the HMPT reactor where
iron oxides are rapidly converted to magnetite under the
influence of a reducing gas. The reduced product, driven
by nitrogen gas, is conveyed to a cooling device for cooling
and discharge, while the residual reducing gas is returned to
the suspension furnace for further combustion with natural
gas. The exhaust gas from the reactor, after two-stage dust
removal and heat exchange, is cooled to below 40°C and
released into the atmosphere, consisting mainly of water
and CO2, which does not pollute the environment.
In the pilot scale test, the HMPT product was milled
to less than 95% passing 38μm and then magnetically sep-
arated in a low intensity magnetic separator. During the
48-hour continuous and stable operation test, sampling
was initiated when the HMPT reactor reached optimum
reaction temperature, with samples taken every 2 hours for
grinding and magnetic separation. The HMPT setup has
the same structure as typical industrial plants and can be
used for pilot scale experiments (Sun et al., 2020). Thus,
the test results are applicable to the design of industrial
equipment.
The chemical composition of the test samples was
determined using Inductively Coupled Plasma (ICP)
spectroscopy and chemical titration methods. The phase
composition and microstructure were characterized and
analyzed using mineral liberation analysis (MLA), X-ray
diffraction (XRD) (PW 3040, Netherlands Cu-Kα radia-
tion, λ =1.541 Å, scanned from 10° to 90° at 40 mA and
40 kV), and scanning electron microscopy coupled with
energy dispersive spectroscopy (SEM-EDS) (SSX-550
operated at 15 kV). The magnetic properties of the prod-
ucts were analyzed using a JDAW-2000D vibrating sample
magnetometer (VSM).
During the HMPT pilot experiment, the concentra-
tion composition of the reducing atmosphere in the sample
was determined using equation (1), and the recovery of the
products was calculated using equation (2).
Table 1. Results of chemical multi-element analysis (%)
TFe FeO CaO SiO
2 F REO
37.72 6.07 11.20 7.40 6.07 5.33
MgO Al2O3 P S K2O Na2O
1.40 1.00 0.28 0.26 0.36 0.24
Figure 1. XRD pattern of raw ore
Table 2. Iron phase composition of the iron ore (%)
Iron phase Fe in Magnetite Fe in Carbonate Fe in Hematite Fe in Sulfide Fe in Silicate Total Iron
Content 17.14 0.49 19.14 0.21 0.86 37.84
Percentage 45.30 1.29 50.58 0.55 2.28 100.00
certain minerals in the ore are decomposed and bound water
is removed, facilitating the subsequent reduction reaction.
The heated sample then enters the HMPT reactor where
iron oxides are rapidly converted to magnetite under the
influence of a reducing gas. The reduced product, driven
by nitrogen gas, is conveyed to a cooling device for cooling
and discharge, while the residual reducing gas is returned to
the suspension furnace for further combustion with natural
gas. The exhaust gas from the reactor, after two-stage dust
removal and heat exchange, is cooled to below 40°C and
released into the atmosphere, consisting mainly of water
and CO2, which does not pollute the environment.
In the pilot scale test, the HMPT product was milled
to less than 95% passing 38μm and then magnetically sep-
arated in a low intensity magnetic separator. During the
48-hour continuous and stable operation test, sampling
was initiated when the HMPT reactor reached optimum
reaction temperature, with samples taken every 2 hours for
grinding and magnetic separation. The HMPT setup has
the same structure as typical industrial plants and can be
used for pilot scale experiments (Sun et al., 2020). Thus,
the test results are applicable to the design of industrial
equipment.
The chemical composition of the test samples was
determined using Inductively Coupled Plasma (ICP)
spectroscopy and chemical titration methods. The phase
composition and microstructure were characterized and
analyzed using mineral liberation analysis (MLA), X-ray
diffraction (XRD) (PW 3040, Netherlands Cu-Kα radia-
tion, λ =1.541 Å, scanned from 10° to 90° at 40 mA and
40 kV), and scanning electron microscopy coupled with
energy dispersive spectroscopy (SEM-EDS) (SSX-550
operated at 15 kV). The magnetic properties of the prod-
ucts were analyzed using a JDAW-2000D vibrating sample
magnetometer (VSM).
During the HMPT pilot experiment, the concentra-
tion composition of the reducing atmosphere in the sample
was determined using equation (1), and the recovery of the
products was calculated using equation (2).
Table 1. Results of chemical multi-element analysis (%)
TFe FeO CaO SiO
2 F REO
37.72 6.07 11.20 7.40 6.07 5.33
MgO Al2O3 P S K2O Na2O
1.40 1.00 0.28 0.26 0.36 0.24
Figure 1. XRD pattern of raw ore
Table 2. Iron phase composition of the iron ore (%)
Iron phase Fe in Magnetite Fe in Carbonate Fe in Hematite Fe in Sulfide Fe in Silicate Total Iron
Content 17.14 0.49 19.14 0.21 0.86 37.84
Percentage 45.30 1.29 50.58 0.55 2.28 100.00