Preparation of solar grade silicon from optical fibers wastes with thermal plasmas

In this paper, we investigated a new way to recycle silica optical fiber wastes for feedstock supply of solar grade silicon (SOG-Si) on the basis of harmless treatment of hazardous wastes, which will provide an alternative route for silicon production processes compared to the conventional silicon supply for photovoltaic industry. Silicon was prepared in hydrogen–argon thermal plasma systems designed by authors and analyzed via X-ray diffractometry, scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray photoelectron spectroscopy, laser Raman spectroscopy and chemical analysis. Only the elements of silicon and oxygen in the production were detected, which suggests that this method is a promising way to prepare high-purity silicon at low cost for feedstock supply of SOG-Si although the content of metallic silicon was above 17 wt% at present.