Speaker
Description
The SisAl Pilot project is an EC H2020 financed collaboration between 21 partners in the (silicon and aluminum) industry, universities and research institutes. It aims to develop the low carbon SisAl process as an alternative to the traditional carbothermic silicon production process.
The SisAl process encompasses the production of silicon alloy by reducing silica (SiO2) in CaO-SiO2 slag aluminothermically to produce the alloy along with a CaO-Al2O3 slag. Before the process can be implemented at a larger industrial scale, the aluminothermic process must be better understood, in particular the kinetics of approaching phase equilibrium.
Initial experiments were performed in a small-scale laboratory environment, where Al in the form of either pure Al-blocks or Al-dross at different amounts were mixed with pre-fused slag with a CaO/SiO2-ratio of 0.7, 1.0 and 1.2, heated to at 1650 °C and held from 20 to 180 minutes. Phases were subsequently separated and analysed. For some trials the effect of kinetics on Si yield was investigated with varying holding times and by upscaling by a factor of approximately 7.5 (in terms of mass) using a larger but similar induction furnace. The results show that (i) the Si alloy is produced rapidly due to liquid-liquid reactions and (ii) the Si yield mainly depend on the separation ability between Si-metal and the CaO-Al2O3 slag. Aluminium dross was found to be a suitable reductant for silica in slag, enabling a circular economy perspective on this secondary stream.
| Speaker Country | Norway |
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