Composition and structural identification of silicon particles in diamond wire saw silicon powder

Abstract

Improving the effective utilization of diamond wire saw silicon powder (DWSSP) waste is bene cial to increasing the production pro t of the photovoltaic (PV) industry. It is also important to reduce the emissions of DWSSP to control environmental pollution. However, the surface oxides of silicon particles in DWSSP hinder its effective utilization. In this study, ve raw DWSSP materials with different oxygen contents were used to reveal the composition and structure of surface oxides. Initially, the presence of amorphous SiO 2 was proved by crystal transformation. Then, the SiO 2 content was determined by SiO 2 -CaO phase diagram analysis, and the SiO x content was determined by using the oxygen conservation rule. The variation trend between the SiO 2 , SiO x , and Si contents in DWSSP and the O content was determined, according to the SiO 2 and SiO x contents. Furthermore, the systematic study of raw DWSSP leads to general formula of the SiO 2 , SiO x , and Si contents with the total O content can be obtained. The three-layer structure of DWSSP was revealed, the DWSSP consisting of a Si core, an intermediate SiO x layer, and a SiO 2 shell. This study can accurately identify the composition and structure of DWSSP and provide a better theoretical basis for the selection and design of the DWSSP recovery process.