Silicon refining by a metallurgical proc

Directional solidification experiments were carried out in a Bridgman furnace to remove carbon and metallic impurities from silicon. For carbon removal, solidification was achieved by extracting the mold from the hot into the cold zone of the furnace, while for the removal of metallic impurities, solidification was conducted by cooling the furnace without moving the mold. In the experiments for carbon removal, a mold extraction speed of 5 µm/s resulted in an ingot with a columnar macrostructure of grains aligned with its central axis and macrosegregation of carbon and SiC particles to the top of the ingot. However, at an extraction speed of 80 µm/s, the macrostructure consisted of columnar grains aligned in the radial direction with SiC particles distributed along the ingot, despite higher concentrations of carbon present, demonstrating severe macrosegregation. In the experiments for the removal of metallic impurities, a columnar grain macrostructure aligned with the ingot’s central axis was obtained, and the concentration profiles of normative impurities exhibited macrosegregation towards the top of the ingot.