Abstract
We have developed a particle-size sorting system using an electrostatic traveling-wave to extract metals such as platinum and indispensable resources contained in small particles of lunar regolith for In-Situ Resource Utilization on the moon. The particles were initially set on the transport substrate inclined for 10-40 °. The substrate is made of polyimide. Then, small particles were transported upward by the electrostatic traveling-wave, and large particles were pulled back to another side of the conveyer by gravitational force. The size-sorting of lunar regolith simulant was experimentally demonstrated when the inclination angle of substrate, the frequency of applied voltage and the pitch between electrodes of substrate were changed. The system could sort particles smaller as the inclination was increased. The optimum frequency was about 10-20 Hz for size sorting in all cases of the inclination ranging 10-40 °. Particles smaller than 23 μm could be sampled when the interelectrode pitch was 1.3 mm, and smaller than 16 μm could be sampled when the interelectrode pitch was 0.8 mm. The system utilizes only the electrostatic force, it doesn’t need gas, liquid, or even mechanical moving parts, and power consumption is small, thus making it suitable for space applications.
