Investigation of Ferrosilicon produced with Si recovered from end-of-life photovoltaic panels

Abstract

Recycling end-of-life (EOL) silicon (Si) PV modules have gathered recent attention from researchers. PV modules can be recycled using a closed loop cycle where the materials recovered are reinjected into the supply chain for producing new modules. However, such solutions are extremely complex, expensive and could lead to further generation of harmful chemicals or emissions. Another way to recycle c-Si PV modules is by using them to produce other commercially important materials, for example ferrosilicon, using an easy and inexpensive route. Ferrosilicon is produced by reduction of silica using carbonaceous sources, which generates planet warming greenhouse gases. In this work, we present a simple method to use recycled Si (reSi) obtained from EOL PV modules to produce FeSi using induction furnace and no carbonaceous source. Along with reSi, metallurgical grade Si and commercial FeSi75 were also used to produce FeSi samples for comparison. FeSi samples with different silicon content were prepared. We also investigate the effect of the oxygen in the processing atmosphere, by preparing samples in arc furnace under argon atmosphere. The samples were characterized using scanning electron microscope coupled with Energy dispersive X-ray spectroscopy, to analyse the microstructure. X-ray diffraction was also used to identify and compare the phases formed in different samples. Hardness of the samples was also determined to understand the ease in the mechanical processing of the samples for potential commercial applications. Through the experimental results we have shown that silicon recovered from EOL PV panels could be used in the fabrication of FeSi.