|About this Abstract
||2020 TMS Annual Meeting & Exhibition
||Solar Cell Silicon
||Molten Salt Electrolysis Production of Solar Silicon from Natural Quartzite
||Aditya Moudgal, Sarat Buasai, Alexander Joseph McMahon, Yi Jie Wu, Adam C. Powell, Uday Pal, Yu Zhong
|On-Site Speaker (Planned)
Polysilicon production for photovoltaics (PV) via the dominant Siemens process is costly due to numerous unit operations, energy-intensity, and inherent safety problems. Molten salt electrolysis reduction of silica could potentially achieve similar energy use and cost to the Hall-Héroult process which produces the world’s aluminum, i.e. 90% lower energy use and 80% lower cost vs. the Siemens process. Recently a new molten salt was engineered for this purpose comprised of CaF₂-MgF₂-YF₃-CaO-SiO₂ with low volatility <0.1 μg/cm²·s, low viscosity <5 mPa·s, high ionic conductivity >4 S/cm and SiO₂ solubility >5 wt%, and inert anode compatibility – an order of magnitude better on all metrics than prior work. This presentation will describe experimental and modeling work to engineer a silicon reduction process using this molten salt. The process produces solid silicon using periodic current reversal to suppress cathodic instabilities.
||Planned: Supplemental Proceedings volume