Abstract
Silicon (Si) is an important material for alloying, solar photovoltaics, and electronics. However, current methods of producing silicon require energy consumption of around 11-13 kWh/kgSi and direct carbon emissions are 4.7-5 tons CO2 per ton Si which conflicts with global efforts to limit climate change. In this work, we discuss several promising methods for reducing or eliminating carbon emissions from the silicon production process. Such methods include using biocarbon, integrating the current process with carbon capture and utilization/storage (CCU/CCS), metallothermic reduction, hydrogen reduction, and molten salt electrolysis. We present the positive aspects and challenges of each approach. Biocarbon coupled with CCU/CCS is the most industrially mature technology and can be carbon-neutral or -negative but is not carbon-free. Hydrogen directly reducing silicon dioxide is not thermodynamically favorable, but it may be viable to use hydrogen in conjunction with other processes to reduce emissions. Metallothermic and electrochemical methods of production are promising and have the potential to create high-purity silicon with no reduction-related carbon emissions but have only been demonstrated at lab scale. Economic viability will likely be the next determining factor for which technologies are more widely researched and implemented.
Original language | American English |
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Journal | Journal of Sustainable Metallurgy |
DOIs | |
State | Published - 2024 |
NREL Publication Number
- NREL/JA-5500-89464
Keywords
- decarbonization
- electrochemistry
- hydrogen
- metallurgy
- silicon