258 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
top size. However, higher throughputs could theoretically
be sustained up to approximately 900 t/h, albeit at lower
resulting specific energy input given the microwave power
supplied. Additional multimode cavity units could also be
added in theory to the system, adding to the system height,
to make use of the additional throughput capacity. Such a
system can be drafted rapidly from basic principles to suit
a particular application and provide a budget cost with
detailed design following to ensure optimization of the
microwave applicator.
What Might Be Available in the Future?
High throughput applications would require a significant
number of 100 kW generators to achieve the microwave
specific energy requirements. For example, a 10,000 t/h
porphyry copper mine demanding 1 kWh/t EMS would
require 100 generators or the equivalent of 33× 300 t/h
modules, which adds significant complexity to the total
system.
For such applications, development of high-power gen-
erators at 433 MHz becomes more attractive. Preliminary
discussions with microwave generator suppliers have indi-
cated that 500 kW generators are feasible in a reasonable
time frame. When coupled with a 650 mm diameter tube
and three microwave feed multimode applicator, a 1,500
t/h system operating at 1 kWh/t EMS could be supported.
Conceptual designs were created to determine the likely
applicator height for incorporation into a plant design, and
the system is comparable in height to the large-scale and
small industrial-scale systems, illustrated in Figure 14.
CONCLUSIONS
The technology for microwave processing of ores has
matured in recent years with the demonstration of a large-
scale treatment system at 150 t/h. The metallurgical testing
results have indicated a range of potential benefits for both
base and precious metal mines and shown potential syner-
gies with new technologies (such as coarse particle flota-
tion) and novel circuits (such as HPGR and stirred mills).
Highlights of the benefits demonstrated in the literature to
date include:
• Up to 70 µm increase in grind size for equivalent
liberation
• Up to 30 µm increase in grind size for equivalent
recovery
• Up to 1% increase in recovery at existing plant grind
sizes
• Up to 10% increase in throughput or reduction in
specific comminution energy at existing plant grind
sizes
• Up to 30% increase in throughput or 20% reduction
in specific comminution energy at a coarser grind
size for equivalent liberation
Routes to scale-up of microwave treatment system have
been identified, but industrial systems in the order of 300
t/h are within reach of the mining industry today.
REFERENCES
Ali, A.Y., Bradshaw, S.M. 2009. Quantifying damage
around grain boundaries in microwave treated ores.
Chemical Engineering and Processing 48:1566–1573.
Ali, A.Y., Bradshaw, S.M. 2010. Bonded-particle model-
ling of microwave-induced damage in ore particles.
Minerals Engineering 23:780–790.
Ali, A.Y., Bradshaw, S.M. 2011. Confined particle bed
breakage of microwave treated and untreated ores.
Minerals Engineering 24:1625–1630.
Large
Scale
Large
Industrial
Scale
896 MHz
2x 100 kW
150 t/h
200 mm
433 MHz
3x 500 kW
1,500 t/h
650 mm
896 MHz
3x 100 kW
300 t/h
400 mm
Small
Industrial
Scale
Source: Modified from Holmes et al. 2020
Figure 14. Concept for 1,500 t/h gravity fed microwave
treatment system compared to large-scale and small
industrial-scale treatment systems
top size. However, higher throughputs could theoretically
be sustained up to approximately 900 t/h, albeit at lower
resulting specific energy input given the microwave power
supplied. Additional multimode cavity units could also be
added in theory to the system, adding to the system height,
to make use of the additional throughput capacity. Such a
system can be drafted rapidly from basic principles to suit
a particular application and provide a budget cost with
detailed design following to ensure optimization of the
microwave applicator.
What Might Be Available in the Future?
High throughput applications would require a significant
number of 100 kW generators to achieve the microwave
specific energy requirements. For example, a 10,000 t/h
porphyry copper mine demanding 1 kWh/t EMS would
require 100 generators or the equivalent of 33× 300 t/h
modules, which adds significant complexity to the total
system.
For such applications, development of high-power gen-
erators at 433 MHz becomes more attractive. Preliminary
discussions with microwave generator suppliers have indi-
cated that 500 kW generators are feasible in a reasonable
time frame. When coupled with a 650 mm diameter tube
and three microwave feed multimode applicator, a 1,500
t/h system operating at 1 kWh/t EMS could be supported.
Conceptual designs were created to determine the likely
applicator height for incorporation into a plant design, and
the system is comparable in height to the large-scale and
small industrial-scale systems, illustrated in Figure 14.
CONCLUSIONS
The technology for microwave processing of ores has
matured in recent years with the demonstration of a large-
scale treatment system at 150 t/h. The metallurgical testing
results have indicated a range of potential benefits for both
base and precious metal mines and shown potential syner-
gies with new technologies (such as coarse particle flota-
tion) and novel circuits (such as HPGR and stirred mills).
Highlights of the benefits demonstrated in the literature to
date include:
• Up to 70 µm increase in grind size for equivalent
liberation
• Up to 30 µm increase in grind size for equivalent
recovery
• Up to 1% increase in recovery at existing plant grind
sizes
• Up to 10% increase in throughput or reduction in
specific comminution energy at existing plant grind
sizes
• Up to 30% increase in throughput or 20% reduction
in specific comminution energy at a coarser grind
size for equivalent liberation
Routes to scale-up of microwave treatment system have
been identified, but industrial systems in the order of 300
t/h are within reach of the mining industry today.
REFERENCES
Ali, A.Y., Bradshaw, S.M. 2009. Quantifying damage
around grain boundaries in microwave treated ores.
Chemical Engineering and Processing 48:1566–1573.
Ali, A.Y., Bradshaw, S.M. 2010. Bonded-particle model-
ling of microwave-induced damage in ore particles.
Minerals Engineering 23:780–790.
Ali, A.Y., Bradshaw, S.M. 2011. Confined particle bed
breakage of microwave treated and untreated ores.
Minerals Engineering 24:1625–1630.
Large
Scale
Large
Industrial
Scale
896 MHz
2x 100 kW
150 t/h
200 mm
433 MHz
3x 500 kW
1,500 t/h
650 mm
896 MHz
3x 100 kW
300 t/h
400 mm
Small
Industrial
Scale
Source: Modified from Holmes et al. 2020
Figure 14. Concept for 1,500 t/h gravity fed microwave
treatment system compared to large-scale and small
industrial-scale treatment systems