Particle Size Sorting
Multi-Stage Sieve Cascade with Electrostatic-Assisted Sieving
A multi-stage sieve cascade separates raw lunar regolith into discrete size fractions—isolating sub-50 µm fines for sintering, 50 to 500 µm particles for beneficiation, and material over 1 mm for construction aggregate—using vibratory screens with 1000, 250, and 50 µm apertures. Lunar operations are constrained by one-sixth gravity, which impedes particle settling under vibration, and vacuum conditions that eliminate convective motor cooling. Furthermore, fine particles below 20 µm agglomerate electrostatically rather than passing through mesh, requiring integrated electrostatic and sonic dispersion aids, while abrasive regolith demands tungsten-coated stainless steel mesh to prevent rapid screen wear during 50 kg/h processing.
Cascade of vibratory mesh sieves at multiple aperture sizes (1 mm, 250 µm, 50 µm) that sorts excavated regolith into well-defined size fractions optimal for downstream processing — fine for sintering, mid-size for beneficiation, coarse for construction aggregate.
Purpose
Achieve the size uniformity each downstream process needs: electrostatic and magnetic beneficiation work best on 50–500 µm fraction; L1-MFG sintering works on <50 µm fines; construction aggregate uses >1 mm coarse fraction. Without sizing, downstream efficiency collapses.
Context
First stage after L3-ISR-TRANS-HOP feed; outputs sized fractions to L3-ISR-BEN-MAG (50-500 µm), L1-MFG (fines), construction stockpile (coarse). Implements electrostatic-assisted sieving from AIAA SciTech 2024 paper for fine sizes.
Principles
- ▸Vibratory screening: regolith on inclined mesh — particles smaller than aperture pass through; larger pass over
- ▸Lunar regolith grain size distribution: median ~70 µm, with very wide spread from sub-µm fines to mm-scale rocks
- ▸Fine particles (<20 µm) tend to agglomerate electrostatically — overcome by tribocharging or sonic agitation
- ▸Electrostatic-assisted sieving (AIAA 2024) disperses fine particles for better classification of 20-100 µm range
- ▸Multi-deck sieve stack: each deck has progressively finer mesh, cascade of separated fractions
- ▸Mesh wear from abrasive regolith requires replaceable screen elements
Typical implementations
- ▸Beneficiation of Lunar Regolith Simulants — Electrostatic Sieving (AIAA SciTech 2024, 10.2514/6.2024-2539)
- ▸Terrestrial mineral processing vibratory screens (Sweco, Rotex)
- ▸NASA KSC Granular Mechanics and Regolith Operations (GMRO) Lab heritage
- ▸Phoenix Mars Lander sieve assembly (heritage 2-stage)
- ▸Lunar regolith simulant production sieves (JSC-1A, LHS-1 LMS-1)
Lunar considerations
- ▸Fine dust agglomeration is the main challenge — electrostatic dispersion essential
- ▸Abrasive wear on screen mesh — tungsten-coated or hardened stainless mesh
- ▸1/6 g reduces particle settling under vibration — adjust vibration frequency/amplitude
- ▸Vacuum eliminates air-pressure-driven sieving issues but also no air cooling of vibrator motor
- ▸Mesh replacement via L1-MNT robotic access ports
- ▸Dust collection on lower decks must prevent re-entrainment to upper decks
Specifications
Functional
| primary function | Size-sort regolith into engineered fractions for downstream use |
| inputs | Raw regolith from L3-ISR-TRANS-HOP, Vibrator drive power from L1-PDM, Tribocharging power for electrostatic-assist sieving |
| outputs | Coarse fraction (>1 mm) to construction stockpile, Mid fraction (50-500 µm) to L3-ISR-BEN-MAG (beneficiation), Fine fraction (<50 µm) to L1-MFG (sintering), Sub-micron fraction (electrostatic recapture) — bulk separated, Process telemetry: throughput, fraction percentages |
| throughput kg per hour | 50 |
| sieve apertures um | 1000, 250, 50 |
| fine dispersion assist | Electrostatic + sonic |
| vibration frequency hz | 50 |
| vibration amplitude mm | 2 |
| power consumption w | 100 |
| mesh replacement interval months | 12 |
Physical
| mass kg | 30 |
| dimensions | 1.0 × 0.6 × 1.2 m stack |
| materials | Tungsten-coated stainless 304 mesh screens, 316L stainless frame and chassis, Vibrator motor (rad-tolerant BLDC), PEEK isolators and dust seals, Hardened-aluminum lower hopper, Electrostatic dispersion electrodes |
| operating temperature c | -40, 80 |
| vacuum compatibility | True |
Operational
| power consumption w | 100 |
| thermal range c | -40, 80 |
| lifetime years | 15 |
| mtbf hours | 30000 |
| mesh replacement per year | 1 |
Interfaces
Provides
- 50-500 µm fraction for magnetic beneficiation
- Same size fraction (via MAG stage) for electrostatic separation
- Fine fraction (<50 µm) for sintering
- Fraction-distribution telemetry
Requires
- Raw regolith feedstock
- Vibrator + electrostatic-assist (~100 W)
Cite this entry
Lunar Ark Codex. "Particle Size Sorting" (L3-ISR-BEN-SIZE). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-ISR-BEN-SIZE
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.