Migration behavior of Pb and Bi impurities during industrial silicon smelting

Organosilicon are widely used in strategic emerging industries such as national defense, high-end equipment, and biomedicine due to their superior properties. Industrial silicon serves as the primary raw material for organosilicon production, yet impurities such as Pb and Bi significantly affect both the production process and the properties of organosilicon. This study investigates the occurrence forms, reaction mechanisms, and migration patterns of Pb and Bi across different temperature zones in an electric arc furnace, aiming to provide a basis for producing industrial silicon with low Pb and Bi content. The furnace was divided into four zones based on material state: the loose material zone at the furnace top, the crust layer, the cavity wall zone, and the bottom product zone. The contents of Pb and Bi decreased in the order: furnace gas > the loose material zone at the furnace top > the crust layer > the cavity wall zone > the bottom product zone. A small amount of Pb and Bi remained in the top loose charge zone due to lower temperatures and shorter reaction time, while PbO, Bi 2 O 3 , and their reduction products volatilized rapidly and adhered to the electrode and furnace walls after charging. The findings provide fundamental insights into the distribution and behavior of Pb and Bi during the silicon smelting process.