XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1937
Lastly, the opportunity of using HPGR to decrease
the energy consumption in the fragmentation was evalu-
ated. For that, initially, the feed was sent for further frag-
mentation on a pilot HPGR located at Weir lab at Venlo,
Netherlands. Consecutive HPGR and screening runs were
carried out, where the discharge of the first HPGR was
screened through a vibrating screen. The oversized mate-
rial was crushed through a secondary HPGR run while the
final product was obtained in screen undersize. This proce-
dure was repeated until all material was obtained in screen
undersize. Two different batches were produced targeting
two different product P80 sizes, 1.5 and 3.5 mm. During
the tests, the focus was to produce samples for downstream
testing and therefore analysis and data evaluation of the
HPGR process was not performed. The particle size distri-
bution of the two products are presented in Figure 6.
The HPGR products were submitted to dry magnetic
separation in a permanent magnet machine (900G) devel-
oped by ArcelorMittal team. The drum speed was adjusted
to maximum and minimum during the tests. The results
(Figure 7) pointed a higher recovery and lower enrichment
ratio for the smaller speed. No significant improvement was
observed in decreasing the particle size distribution of the
product of HPGR. A more detailed study of the crushing
at HPGR process is suggested to determine productivity
and conditions to produce both materials and valuate the
possibility of using the HPGR in the material before the
crushing from 40 to 8 mm.
and conditions to produce both materials and valuate the
possibility of using the HPGR in the material before the
crushing from 40 to 8 mm.
CONCLUSIONS
The material to be concentrated is composed by magnetite,
43%, and many other gangues, mainly different silicates,
totaling 48,6%. Magnetite liberation is achieved in coarse
size, –425 µm, but gangue minerals do not achieve libera-
tion above 80% even at finer sizes. Magnetite recovery pre-
sented a high recovery, close to 95%, at Davis Magnetic
Tube in the size range from 400 to 100 µm. Bond work
index of pre-concentrate sample was 12.2 kWh/t. Grinding
this material aiming a P80 of 105µm presented a good per-
formance in lab wet LIMS: 66% of iron in the concentrate
and 82% of iron recovery. The two materials, with different
particle sizes, produced by HPGR presented similar perfor-
mance in the dry LIMS.
Table 2. Performance of magnetic separation
Stage Flow Iron Content, %Mas Recovery, %Iron Recovery, %
Rougher Concentrate 64.3 73.5 90.7
Tailings 18.3 26.5 9.3
Cleaner Concentrate 66.1 70.1 81.9
Tailings 26.6 3.4 8.8
Figure 6. Particle size distribution of material produce by HPGR
Lastly, the opportunity of using HPGR to decrease
the energy consumption in the fragmentation was evalu-
ated. For that, initially, the feed was sent for further frag-
mentation on a pilot HPGR located at Weir lab at Venlo,
Netherlands. Consecutive HPGR and screening runs were
carried out, where the discharge of the first HPGR was
screened through a vibrating screen. The oversized mate-
rial was crushed through a secondary HPGR run while the
final product was obtained in screen undersize. This proce-
dure was repeated until all material was obtained in screen
undersize. Two different batches were produced targeting
two different product P80 sizes, 1.5 and 3.5 mm. During
the tests, the focus was to produce samples for downstream
testing and therefore analysis and data evaluation of the
HPGR process was not performed. The particle size distri-
bution of the two products are presented in Figure 6.
The HPGR products were submitted to dry magnetic
separation in a permanent magnet machine (900G) devel-
oped by ArcelorMittal team. The drum speed was adjusted
to maximum and minimum during the tests. The results
(Figure 7) pointed a higher recovery and lower enrichment
ratio for the smaller speed. No significant improvement was
observed in decreasing the particle size distribution of the
product of HPGR. A more detailed study of the crushing
at HPGR process is suggested to determine productivity
and conditions to produce both materials and valuate the
possibility of using the HPGR in the material before the
crushing from 40 to 8 mm.
and conditions to produce both materials and valuate the
possibility of using the HPGR in the material before the
crushing from 40 to 8 mm.
CONCLUSIONS
The material to be concentrated is composed by magnetite,
43%, and many other gangues, mainly different silicates,
totaling 48,6%. Magnetite liberation is achieved in coarse
size, –425 µm, but gangue minerals do not achieve libera-
tion above 80% even at finer sizes. Magnetite recovery pre-
sented a high recovery, close to 95%, at Davis Magnetic
Tube in the size range from 400 to 100 µm. Bond work
index of pre-concentrate sample was 12.2 kWh/t. Grinding
this material aiming a P80 of 105µm presented a good per-
formance in lab wet LIMS: 66% of iron in the concentrate
and 82% of iron recovery. The two materials, with different
particle sizes, produced by HPGR presented similar perfor-
mance in the dry LIMS.
Table 2. Performance of magnetic separation
Stage Flow Iron Content, %Mas Recovery, %Iron Recovery, %
Rougher Concentrate 64.3 73.5 90.7
Tailings 18.3 26.5 9.3
Cleaner Concentrate 66.1 70.1 81.9
Tailings 26.6 3.4 8.8
Figure 6. Particle size distribution of material produce by HPGR
