XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 351
In contrast, lunar regolith, the fine, dry layer of par-
ticles that covers the surface of the Moon to a depth of up
to 20 m presents a target resource that is widely available
and versatile. Lunar regolith, with a typical average particle
size (d50) of 70 µm (Crawford, 2015 Heiken et al., 1991),
comprises a complex mixture of rock fragments, mineral
particles, glasses and abrasive agglutinates. It can be used
in numerous different ISRU applications, for example, to
produce oxygen and metals, as well as provide shelter, habi-
tation, and infrastructure.
Beneficiation of Lunar Regolith
The extraction of oxygen from lunar regolith can be described
by a simple flowsheet in which the resource of interest is
excavated, beneficiated and extracted to produce the final
product. The inclusion of a beneficiation stage affects both
mining rate and reactor size (Cilliers et al., 2020). Figure 1
gives an example of a theoretical study to illustrate this. The
trade-off between mining rate and reactor size as a function
of the scale of beneficiation has important implications for
energy consumption, equipment design and scale, opera-
tion mode (e.g., batch or continuous) and environmental
legacy (i.e., excavated area) for lunar ISRU. Moreover, it
constrains the design of excavation, materials handling, and
beneficiation equipment.
The environmental conditions of the expected ISRU
operating system and engineering constraints (e.g., energy,
throughput, efficiency, etc.) must also be incorporated into
the design of technology. Development of integrated, end-
to-end SRU processes is currently limited by a lack of data
on regolith characteristics, particularly in-situ (e.g., electro-
static charge) and the low TRL of extraction technologies.
The environmental conditions will also affect the design
and operation of any process, for example:
• Variation in the electrostatic properties of regolith
under different conditions (e.g., day/night)
• Designing for low gravity and low/no atmosphere
• Designing to withstand or exploit high/low
temperatures
• Designing for operation in dusty environments and
• Designing for reliability and durability.
There is limited knowledge of the material properties of
lunar regolith under lunar conditions. It is known to be
abrasive, exhibit strong cohesive properties, and be highly
electrostatically charged. Any process that operates in or
with lunar regolith will need to be designed to withstand
the challenges presented by this complex material.
Beneficiation has been largely overlooked in ISRU
research. This has been driven by the lack of specficiations
Figure 1. Trade-off between excavation rate and reactor feed rate for different
beneficiation scenarios (from Cilliers et al., 2020)
In contrast, lunar regolith, the fine, dry layer of par-
ticles that covers the surface of the Moon to a depth of up
to 20 m presents a target resource that is widely available
and versatile. Lunar regolith, with a typical average particle
size (d50) of 70 µm (Crawford, 2015 Heiken et al., 1991),
comprises a complex mixture of rock fragments, mineral
particles, glasses and abrasive agglutinates. It can be used
in numerous different ISRU applications, for example, to
produce oxygen and metals, as well as provide shelter, habi-
tation, and infrastructure.
Beneficiation of Lunar Regolith
The extraction of oxygen from lunar regolith can be described
by a simple flowsheet in which the resource of interest is
excavated, beneficiated and extracted to produce the final
product. The inclusion of a beneficiation stage affects both
mining rate and reactor size (Cilliers et al., 2020). Figure 1
gives an example of a theoretical study to illustrate this. The
trade-off between mining rate and reactor size as a function
of the scale of beneficiation has important implications for
energy consumption, equipment design and scale, opera-
tion mode (e.g., batch or continuous) and environmental
legacy (i.e., excavated area) for lunar ISRU. Moreover, it
constrains the design of excavation, materials handling, and
beneficiation equipment.
The environmental conditions of the expected ISRU
operating system and engineering constraints (e.g., energy,
throughput, efficiency, etc.) must also be incorporated into
the design of technology. Development of integrated, end-
to-end SRU processes is currently limited by a lack of data
on regolith characteristics, particularly in-situ (e.g., electro-
static charge) and the low TRL of extraction technologies.
The environmental conditions will also affect the design
and operation of any process, for example:
• Variation in the electrostatic properties of regolith
under different conditions (e.g., day/night)
• Designing for low gravity and low/no atmosphere
• Designing to withstand or exploit high/low
temperatures
• Designing for operation in dusty environments and
• Designing for reliability and durability.
There is limited knowledge of the material properties of
lunar regolith under lunar conditions. It is known to be
abrasive, exhibit strong cohesive properties, and be highly
electrostatically charged. Any process that operates in or
with lunar regolith will need to be designed to withstand
the challenges presented by this complex material.
Beneficiation has been largely overlooked in ISRU
research. This has been driven by the lack of specficiations
Figure 1. Trade-off between excavation rate and reactor feed rate for different
beneficiation scenarios (from Cilliers et al., 2020)