SisAl: CO2 free production of silicon using aluminium scrap and process waste

The project will demonstrate a CO2-free step-change production process for silicon metal and silicon - aluminium alloys at TRL 6-8. The recently patented production process applies Al scrap and/or aluminum dross to metallothermically reduce quartz in liquid CaO-SiO2 slag, producing Si or an AlSi alloy and a CaO-Al2O3 slag, which is, in turn, hydrometallurgically treated to produce alumina (Al2O3) and calcia (CaO). The CaO is recycled into the making of the CaO-SiO2 slag which is used in the reduction process. The main advantages of this new integrated process are the following: - The process is CO2 free and has a lower specific energy consumption than the current SAF process. Depending on material input, different products may be produced - The process reconstitutes waste material (currently landfilled) from the aluminum process to primary feed for the Al electrolysis process - The process is very versatile in the use of raw materials; it can use quartz fines (currently landfilled) which is not possible in the current SAF Si production process, and the ratio of Al dross/scrap reductants can be varied and may be replaced with high purity Al to produce very high purity Si. - With the recirculation of CaO and Al2O3 materials, the only main consumable material in the present process is quartz. - The process does not generate NOx, dust or other harmful emissions and has a very high raw material yield. The project will be organized in several work packages (WP) as shown below. WP1: Raw materials WP2: Pyrometallurgical treatment W3: Reduction and refining WP4: Hydrometallurgy WP5: Electrolysis WP6: Business concepts WP7: Technical and environmental impact WP8: Dissemination and clustering WP9: Management