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Beneficiation of Ultrafine Iron Ore Using
Tribo‑Electrostatic Separator
Tom Newman, Abhishek Gupta
ST Equipment &Technology LLC
Christina Poelzl
University of Leoben
ABSTRACT: ST Equipment &Technology (STET) has developed a dry separation system using a tribo-
electrostatic belt separator. This technology does not require water or chemical additives. Commercial scale
STET separators are utilized in the processing of barite, talc, and other industrial minerals. Typically, ultra-
fine iron ore (10 micron particle size) is not effectively processed by conventional industrial processes and is
disposed of as tailings. The beneficiation results described in this paper demonstrate that such ultrafine ores
can be enriched using the tribo-electrostatic separation technology. Beneficiation results from testing a coarser,
air-classified iron ore are also presented demonstrating versatility and effectiveness of STET dry electrostatic
separation technology in processing iron ore.
INTRODUCTION
The STET separator utilizes electrical charge differences
between materials produced by surface contact or tribo-
electric charging. When two materials are in contact, mate-
rial with a higher affinity for electrons gains electrons and
thus charges negative, while material with lower electron
affinity charges positive. This electron affinity is dependent
on the chemical composition of the particle surface and
results in differential charging of materials in a mixture of
discrete particles of different composition. In the separator,
the material is fed into a thin gap (0.9–1.5 cm) between
two parallel planar electrodes charged up to ±10 kV. The
particles acquire opposite charges through interparticle
contact. Charged particles are attracted to the electrode
plate of opposite charge. A continuous-loop, high-speed,
open-mesh belt moves differently charged particles towards
opposite ends of the separator. The counter current flow of
the separating particles and continual triboelectric charging
provides for a multi-stage separation and results in excel-
lent purity and recovery in a single-pass unit. The STET
separator is relatively compact: 9.1 m long, 1.7 m wide,
and 3.2 m high. The separator power consumption is about
1 kWhr/tonne of material processed (Bittner et al., 2014).
Iron ore is a valuable commodity used for steel manu-
facturing, which is a key part of the modern economy (Lu
2015). Today, banded iron formations are an important
source of iron ore for mineral extraction (M.I.I. n.d.). The
iron bearing minerals typically mined from such deposits
are magnetite and hematite [Klemic et al., 1973]. The iron
bearing minerals must be separated from the gangue miner-
als that accompany them, typically quartz, clays like kaolin-
ite, and alumina bearing minerals like gibbsite (Flippov et
al., 2014). Traditionally, iron ore is enriched by using either
flotation or magnetic separation to selectively remove these
Beneficiation of Ultrafine Iron Ore Using
Tribo‑Electrostatic Separator
Tom Newman, Abhishek Gupta
ST Equipment &Technology LLC
Christina Poelzl
University of Leoben
ABSTRACT: ST Equipment &Technology (STET) has developed a dry separation system using a tribo-
electrostatic belt separator. This technology does not require water or chemical additives. Commercial scale
STET separators are utilized in the processing of barite, talc, and other industrial minerals. Typically, ultra-
fine iron ore (10 micron particle size) is not effectively processed by conventional industrial processes and is
disposed of as tailings. The beneficiation results described in this paper demonstrate that such ultrafine ores
can be enriched using the tribo-electrostatic separation technology. Beneficiation results from testing a coarser,
air-classified iron ore are also presented demonstrating versatility and effectiveness of STET dry electrostatic
separation technology in processing iron ore.
INTRODUCTION
The STET separator utilizes electrical charge differences
between materials produced by surface contact or tribo-
electric charging. When two materials are in contact, mate-
rial with a higher affinity for electrons gains electrons and
thus charges negative, while material with lower electron
affinity charges positive. This electron affinity is dependent
on the chemical composition of the particle surface and
results in differential charging of materials in a mixture of
discrete particles of different composition. In the separator,
the material is fed into a thin gap (0.9–1.5 cm) between
two parallel planar electrodes charged up to ±10 kV. The
particles acquire opposite charges through interparticle
contact. Charged particles are attracted to the electrode
plate of opposite charge. A continuous-loop, high-speed,
open-mesh belt moves differently charged particles towards
opposite ends of the separator. The counter current flow of
the separating particles and continual triboelectric charging
provides for a multi-stage separation and results in excel-
lent purity and recovery in a single-pass unit. The STET
separator is relatively compact: 9.1 m long, 1.7 m wide,
and 3.2 m high. The separator power consumption is about
1 kWhr/tonne of material processed (Bittner et al., 2014).
Iron ore is a valuable commodity used for steel manu-
facturing, which is a key part of the modern economy (Lu
2015). Today, banded iron formations are an important
source of iron ore for mineral extraction (M.I.I. n.d.). The
iron bearing minerals typically mined from such deposits
are magnetite and hematite [Klemic et al., 1973]. The iron
bearing minerals must be separated from the gangue miner-
als that accompany them, typically quartz, clays like kaolin-
ite, and alumina bearing minerals like gibbsite (Flippov et
al., 2014). Traditionally, iron ore is enriched by using either
flotation or magnetic separation to selectively remove these