Abstract
Since 2014 silicon (Si) has been classified as a critical raw material by the European Union due to its high risk of supply disruption and significant economic importance. The SisAl process for Si production reduces direct CO2 emissions and also promotes the utilisation of secondary raw materials such as quartz fines, aluminium dross, and scrap, enabling a shift from today's carbothermic reduction process to a process in line with circular economy goals. The present study focuses on the purification of a Si alloy acquired from slag-refined mixture of SisAl metal and kerf. 99.9% pure silicon was successfully obtained by utilising the directional solidification method, which relies on the different distribution of impurities during metal solidification. As an alternative, the Si alloy was also blended with high-purity Si and subjected to refinement by crystal pulling to assess its suitability for applications demanding very high Si purity. In this process, an ingot with 5N purity was obtained.