1
25-043
Improvements in Magnetite Processing Utilising Magnetic
Separation Technologies
George Mandarakas
STEINERT Australia
Karl-Heinz Becker
STEINERT GmbH
Johan van Zyl
STEINERT Australia
ABSTRACT
The world’s climate today has changed compared to 10 or
20 years ago. Many countries face water shortages water
sourcing for mining activities has become harder to secure.
ESG’s focus on the industry has made us more aware of
the need to preserve and responsibly use the water needed
for wet processing in our milling and sorting activities. In
a recent greenfield project in South Australia, 10 Gigalitres
per annum would be required to process 5Mtpa of magne-
tite [1].
Published information indicates that the mining
industry consumes approximately 12 EJ per year—or 3.5%
of total global final energy consumption globally [2] or
3.33 trillion kilowatt hrs. This energy consumption is
significant, considering the critical role mining plays in
extracting and processing essential minerals for economic
development and human progress.
The perception of the mining industry is that not only
does it consume significant power, but it also consumes
a lot of the freshwater in the world. In fact, it consumes
approximately 5% [3] of the total freshwater demand.
According to the Intergovernmental Panel on Climate
Change (IPCC), by 2050, 60% of the world’s population
will be living in countries that are classed as water-stressed
[3]. As more and more emphasis is placed on renewable
energy sources, the amount of water used in mineral pro-
cessing will increase because more and more raw materials
require a water-intensive process. This increases the pres-
sure on the mining industry to try and find water-saving
initiatives.
As part of this review, recent advancements in mag-
nets have enabled magnetite processing facilities to achieve
between 30 to 40% dry gangue material rejection before
the wet beneficiation process (grinding and sorting). This
reduction in energy consumption allows the reduction
of energy consumption. Secondly, there is less material
ground in the mills, which requires less water for mineral
downstream processing.
INTRODUCTION
The recent use of high-speed dry drums with non-metallic
drums and rare earth magnets has enabled the industry to
break from the traditional steel drums susceptible to eddy
currents at high speeds when applied in magnetite circuits.
Including these new generation high-speed dry drums into
the comminution circuit has reduced the closed circuit
loads associated with HPGR circuits and crushing circuits
by the early removal of gangue material.
The units are typically used in the tertiary section of
the circuit where the tertiary circuit has liberated sufficient
mineralisation. What distinguishes these units from other
dry drums is that they can operate at higher speeds than tra-
ditional steel drums without inducing eddy current effects.
Eddy current needs to be avoided for the following reasons:
• They create their magnetic fields that oppose the
original magnetic field.
• They result in energy loss due to converting electrical
energy into heat.
• They create drag on the motion involved.
• They react back on the source of the magnetic field
according to Lenz’s Law.
25-043
Improvements in Magnetite Processing Utilising Magnetic
Separation Technologies
George Mandarakas
STEINERT Australia
Karl-Heinz Becker
STEINERT GmbH
Johan van Zyl
STEINERT Australia
ABSTRACT
The world’s climate today has changed compared to 10 or
20 years ago. Many countries face water shortages water
sourcing for mining activities has become harder to secure.
ESG’s focus on the industry has made us more aware of
the need to preserve and responsibly use the water needed
for wet processing in our milling and sorting activities. In
a recent greenfield project in South Australia, 10 Gigalitres
per annum would be required to process 5Mtpa of magne-
tite [1].
Published information indicates that the mining
industry consumes approximately 12 EJ per year—or 3.5%
of total global final energy consumption globally [2] or
3.33 trillion kilowatt hrs. This energy consumption is
significant, considering the critical role mining plays in
extracting and processing essential minerals for economic
development and human progress.
The perception of the mining industry is that not only
does it consume significant power, but it also consumes
a lot of the freshwater in the world. In fact, it consumes
approximately 5% [3] of the total freshwater demand.
According to the Intergovernmental Panel on Climate
Change (IPCC), by 2050, 60% of the world’s population
will be living in countries that are classed as water-stressed
[3]. As more and more emphasis is placed on renewable
energy sources, the amount of water used in mineral pro-
cessing will increase because more and more raw materials
require a water-intensive process. This increases the pres-
sure on the mining industry to try and find water-saving
initiatives.
As part of this review, recent advancements in mag-
nets have enabled magnetite processing facilities to achieve
between 30 to 40% dry gangue material rejection before
the wet beneficiation process (grinding and sorting). This
reduction in energy consumption allows the reduction
of energy consumption. Secondly, there is less material
ground in the mills, which requires less water for mineral
downstream processing.
INTRODUCTION
The recent use of high-speed dry drums with non-metallic
drums and rare earth magnets has enabled the industry to
break from the traditional steel drums susceptible to eddy
currents at high speeds when applied in magnetite circuits.
Including these new generation high-speed dry drums into
the comminution circuit has reduced the closed circuit
loads associated with HPGR circuits and crushing circuits
by the early removal of gangue material.
The units are typically used in the tertiary section of
the circuit where the tertiary circuit has liberated sufficient
mineralisation. What distinguishes these units from other
dry drums is that they can operate at higher speeds than tra-
ditional steel drums without inducing eddy current effects.
Eddy current needs to be avoided for the following reasons:
• They create their magnetic fields that oppose the
original magnetic field.
• They result in energy loss due to converting electrical
energy into heat.
• They create drag on the motion involved.
• They react back on the source of the magnetic field
according to Lenz’s Law.