XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 97
from a 9.5% silica feed however, at 20 mesh and coarser,
there is little or no upgrading of feed.
The key to operating the concentrator was to produce
a wet concentrate that after drying performed best in high-
tension, which did not necessarily have the lowest silica
content. High tension electrostatic separators concentrate
good electrical conductors (like iron oxide) from non-con-
ductors (such as silicates) but are also affected by momen-
tum, which is a function of the separator’s drum speed and
the particle’s size and density (weight).
Dry Low- and Medium-Intensity Magnetic
Separation—Operational Example No. 2 of 2
A simple low- and medium-intensity dry magnetic drum
separator beneficiation pilot plant was engineered and built
at the base of the Pampa El Toro sand dune near the vil-
lage of Acari (Figure 8) to reject silica from magnetite and
titano-magnetite concentrates from iron sand. It was oper-
ated for three separate campaigns during 2008 and pro-
duced 60 tons of iron ore concentrate at a grade of 64%
Fe. Dry screening at 180 μm was added before Campaign
III that scalped a coarse middling material and increased
the grade to 67% Fe with only small iron losses. These iron
losses were subsequently recovered by the addition of a dry
grinding circuit and recirculation to scavenge this fraction.
A wire mesh screen was employed and quickly blinded,
which was solved by using polyurethane screens instead and
is considered a lesson learned.
During commissioning of the pilot plant (Campaign
I), approximately 83 tons of the feed sand was processed,
producing 4.8 tonnes of iron concentrate at 47.9% Fe
(Table 1). During Campaign II, it was determined that
the plant was being underfed even when the feed hopper
was completely open. To solve this, the feed bin discharge
was cut with a torch to increase the feed rate by 10-times
which confirmed that the drums were being underfed while
improving product grade and recovery. Initial rates of 1
ton/hour/foot of drum length were increased to 10 tons/
hour/foot. The pilot plant throughput was improved from
2.8 to 27 tons per hour. The average feed grade for the head
sand of the ROM was determined to be 7.3% Fe. A total
of 46 tons of magnetic concentrate at a grade of 55.5% Fe
was produced from 613 tonnes of head sand resulting in a
weight recovery of 7.5%. The concentrate was produced
Figure 7. Performance by particle size for electrostatic
separation
Figure 8. Cardero’s PeT pilot plant
from a 9.5% silica feed however, at 20 mesh and coarser,
there is little or no upgrading of feed.
The key to operating the concentrator was to produce
a wet concentrate that after drying performed best in high-
tension, which did not necessarily have the lowest silica
content. High tension electrostatic separators concentrate
good electrical conductors (like iron oxide) from non-con-
ductors (such as silicates) but are also affected by momen-
tum, which is a function of the separator’s drum speed and
the particle’s size and density (weight).
Dry Low- and Medium-Intensity Magnetic
Separation—Operational Example No. 2 of 2
A simple low- and medium-intensity dry magnetic drum
separator beneficiation pilot plant was engineered and built
at the base of the Pampa El Toro sand dune near the vil-
lage of Acari (Figure 8) to reject silica from magnetite and
titano-magnetite concentrates from iron sand. It was oper-
ated for three separate campaigns during 2008 and pro-
duced 60 tons of iron ore concentrate at a grade of 64%
Fe. Dry screening at 180 μm was added before Campaign
III that scalped a coarse middling material and increased
the grade to 67% Fe with only small iron losses. These iron
losses were subsequently recovered by the addition of a dry
grinding circuit and recirculation to scavenge this fraction.
A wire mesh screen was employed and quickly blinded,
which was solved by using polyurethane screens instead and
is considered a lesson learned.
During commissioning of the pilot plant (Campaign
I), approximately 83 tons of the feed sand was processed,
producing 4.8 tonnes of iron concentrate at 47.9% Fe
(Table 1). During Campaign II, it was determined that
the plant was being underfed even when the feed hopper
was completely open. To solve this, the feed bin discharge
was cut with a torch to increase the feed rate by 10-times
which confirmed that the drums were being underfed while
improving product grade and recovery. Initial rates of 1
ton/hour/foot of drum length were increased to 10 tons/
hour/foot. The pilot plant throughput was improved from
2.8 to 27 tons per hour. The average feed grade for the head
sand of the ROM was determined to be 7.3% Fe. A total
of 46 tons of magnetic concentrate at a grade of 55.5% Fe
was produced from 613 tonnes of head sand resulting in a
weight recovery of 7.5%. The concentrate was produced
Figure 7. Performance by particle size for electrostatic
separation
Figure 8. Cardero’s PeT pilot plant