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ABSTRACT Currently, the main material for the production of solar cells is still silicon. More than 70% of the global production of solar cells are silicon based. For solar-grade silicon production the technologies based on the reduction of silicon from organosilicon compounds are mainly used. These technologies are energy-consuming, highly explosive and unsustainable. The present paper studies the technology of purification of metallurgical-grade silicon by vacuum-thermal and plasma-chemical treatment of silicon melt under electromagnetic stirring using numerical simulation and compares this technology with the existing ones (silane technologies and Elkem Solar silicon (ESS) production process) in terms of energy consumption, environmental safety and the process scalability. It is shown that the proposed technology is environmentally safe, scalable and has low power consumption. The final product of this technology is multicrystalline silicon, ready for silicon wafer production.
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Solid Oxide Membrane (SOM)-Based Technology for Carbon-Free Efficient Production of Solar-Grade Silicon
State-of-the-art solar-grade silicon production is energy intensive and has a negative impact on the environment. Due to the robust and rapid growth of the Si-based photovoltaic (PV) industry, it is necessary to develop a greener technology for silicon production. Solid oxide membrane (SOM) electrolysis is a proven versatile green technology that can be developed to economically produce many important metal or metal compounds from their oxides. This work will discuss application of SOM electrolysis to produce solar-grade silicon from silica in a single-step resulting in net-zero-carbon emission. The high-temperature SOM electrolysis cell employs stable molten oxide-fluoride bath with silicon wafer cathode and stabilized zirconia membrane-based novel anodes. The cell design and process parameters are selected to enable silicon deposition on the Si wafer cathode. However, initially an electrochemical oxidation reaction occurred between silicon and oxygen that involved the cathode/flux/gas interfaces. An approach to successfully prevent this side reaction has been demonstrated. Electrochemical characterization of the SOM process is presented, and post-experimental characterization demonstrates Si deposits in the form of silicon carbide due to the use of graphite crucible and graphite current collector.
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- Award ID(s):
- 1937829
- PAR ID:
- 10389906
- Editor(s):
- Lazou, A.; Daehn, K.; Fleuriault, C.; Gökelma, M.; Olivetti, E.; Meskers, C
- Date Published:
- Journal Name:
- REWAS 2022: Developing Tomorrow’s Technical Cycles (Volume I)
- Volume:
- I
- Page Range / eLocation ID:
- 659-668
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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