Preliminary Techno-Economic Considerations of the Sisal Process - Closing Materials Loops through Industrial Symbiosis
11 Pages Posted: 23 May 2022
Date Written: April 6, 2022
The SisAl process utilizes secondary raw materials such as aluminium (Al) scrap and aluminium dross as replacements for the carbon reductants used in today’s SAF-based metallurgical grade silicon (MG-Si) process, avoiding direct CO2 emissions and other pollutants. The SisAl concept proposes that the aluminium industry can act as both a supplier of secondary Al and end user of the MG-Si produced by the SisAl process in the silicon (Si) industry, enabling a new industrial symbiosis model. Norway is the largest producer of both silicon and aluminium in Europe ('USGS' 2021), and the SisAl concept hence represents an opportunity for resource-efficient industrial growth and circularity for Norwegian Si and Al industries. The first pilot scale results from the Horizon 2020 project SisAl Pilot are presented, illustrating the potential for making MG-Si at 98% purity by first producing an Si-Ca-Al alloy through aluminothermic reduction of calcia-silica slag followed by refining of the alloy using slag sculls. Economic considerations coupled to the technical pilot results and beyond are discussed.
Keywords: silicon, alumina, industrial symbiosis, industrial transformation
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