XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 353
technology also include whether or not to include the pro-
cess in the first place.
Size Classification for Lunar Regolith
The lunar regolith contains mineral fragments, pyroclas-
tic glasses, and agglutinates. There are two broad regions
of lunar regolith—the “mare” and the “highland” regions.
These differ in their composition, with mare being basaltic
and iron-rich, while highland is predominantly anortho-
site. Returned samples from the Apollo missions were cata-
logued and split. Sampling was not representative, but was
rather driven by interest and opportunity. Sampling tools
included rakes and scoops, some of which had grates to
filter out the larger particles. All details of sample handling
and processing are available in the public domain and pro-
vide a fascinating overview of NASA curation procedure at
that time.
Subsequent analysis of the samples gives rise to the
finding that the lunar regolith particle size distribution is
fine, with a d50 of around 70 µm, and that most particles
are smaller than 1 mm. However, returning to the original
samples demonstrates that this is dependent on the sample
considered. Figure 3 shows an alternative analysis of several
Apollo-era samples, in which many of the samples contain
significant fractions of particles 1 mm. This analysis dem-
onstrates the challenges in designing equipment and pro-
cesses under significant uncertainty.
Based on the analysis, it can be assumed that many
processes using the lunar regolith are not designed for par-
ticles greater than 1 mm, and therefore a target for size clas-
sification is to remove the 1 mm size fraction. We adapt
a centrifugal size classifier concept to study the separation
of +1 mm particles for a lunar regolith simulant. The goal
of the study is to determine the feasibility of the system
for meeting the target of separating particles by size, while
illustrating some of the differences between the approach
of terrestrial mineral processing and beneficiation for space
resources.
MATERIALS AND METHODS
Materials
In this study, lunar regolith simulant LHS-1 was used.
This simulant is produced commercially by Space Resource
Technologies (SRT, formerly Exolith Lab) in the United
States. The SRT simulants focus on the mineralogical
compositions in the products, i.e., composed of multiple
Figure 2. Two example physical separation flowsheets, taken from Wills &Finch (2015). LHS: A magnetic separation
flowsheet with a single target product. RHS: A beach sands processing flowsheet producing multiple products
technology also include whether or not to include the pro-
cess in the first place.
Size Classification for Lunar Regolith
The lunar regolith contains mineral fragments, pyroclas-
tic glasses, and agglutinates. There are two broad regions
of lunar regolith—the “mare” and the “highland” regions.
These differ in their composition, with mare being basaltic
and iron-rich, while highland is predominantly anortho-
site. Returned samples from the Apollo missions were cata-
logued and split. Sampling was not representative, but was
rather driven by interest and opportunity. Sampling tools
included rakes and scoops, some of which had grates to
filter out the larger particles. All details of sample handling
and processing are available in the public domain and pro-
vide a fascinating overview of NASA curation procedure at
that time.
Subsequent analysis of the samples gives rise to the
finding that the lunar regolith particle size distribution is
fine, with a d50 of around 70 µm, and that most particles
are smaller than 1 mm. However, returning to the original
samples demonstrates that this is dependent on the sample
considered. Figure 3 shows an alternative analysis of several
Apollo-era samples, in which many of the samples contain
significant fractions of particles 1 mm. This analysis dem-
onstrates the challenges in designing equipment and pro-
cesses under significant uncertainty.
Based on the analysis, it can be assumed that many
processes using the lunar regolith are not designed for par-
ticles greater than 1 mm, and therefore a target for size clas-
sification is to remove the 1 mm size fraction. We adapt
a centrifugal size classifier concept to study the separation
of +1 mm particles for a lunar regolith simulant. The goal
of the study is to determine the feasibility of the system
for meeting the target of separating particles by size, while
illustrating some of the differences between the approach
of terrestrial mineral processing and beneficiation for space
resources.
MATERIALS AND METHODS
Materials
In this study, lunar regolith simulant LHS-1 was used.
This simulant is produced commercially by Space Resource
Technologies (SRT, formerly Exolith Lab) in the United
States. The SRT simulants focus on the mineralogical
compositions in the products, i.e., composed of multiple
Figure 2. Two example physical separation flowsheets, taken from Wills &Finch (2015). LHS: A magnetic separation
flowsheet with a single target product. RHS: A beach sands processing flowsheet producing multiple products