Design and optimisation of rotary vibrating screening process in silicon photovoltaic panel recycling: A particle-scale model study

Abstract

The efficient separation of crushed solar panel particles is a critical step in photovoltaics (PV) recycling. In this paper, a DEM-based computer model is used to investigate the separation of crushed solar panel particles in a variety of shapes (including rod-like glass particles and chip-like solar cell particles and small broken residue) at the particle scale in a lab-scale rotary vibrating screen. The screening process of individual particles, including looseness, stratification, collision and penetration, can be well captured by the DEM simulations. Then the effects of several key vibration parameters on screening efficiency are studied, including circular displacements and oscillatory amplitude and frequency, and their underlying mechanism is explored at the particle scale. The simulation results show that with the increase of circular displacements from 1 to 3 mm, the screening efficiency increases from 89.5% to 91.8%. With the rise of oscillatory amplitude from 0.1° to 0.6°, the screening efficiency decreases significantly from 92.0% to 87.3%. With the increase of oscillatory frequency from 10 Hz to 25 Hz, the screening efficiency decreases slightly from 92.1% to 91.2%. The optimal screening condition is identified, i.e., >3 mm circular displacement, <0.1° oscillatory amplitude, and < 10 Hz oscillatory frequency, significantly enhancing screening efficiency. This study is helpful for rotary vibrating screen device scale-up and process optimisation in the PV recycling industry.