Research on distribution of aluminum in electron beam melted silicon ingot

• Al behavior in liquid Si was experimentally studied during electron beam refining, followed by solidification.
• The refining process of Al was modeled based on basic evaporation model and experimental results.
• The model was extended by a solidification step, which modeled the experimental results fairly well.
• The removal efficiency in most area of electron beam melted Si ingot was more than 97%.

The purification of metallurgical grade silicon, especially the removal of aluminum, was investigated by electron beam melting and solidification. Small amounts of silicon raw materials were melted in an electron beam furnace with same melting time and different solidification time to obtain the distribution of Al in silicon ingot. The removal mechanisms in different stages were also discussed. The results show that the removal of Al during melting process only depends on evaporation and that during solidification process depends on both segregation and evaporation. The distribution of Al shows an obvious increasing trend from the bottom to the top of the silicon ingot when solidification time is 600 s. The removal efficiency in most area is close to that in the ingot solidified instantaneously, but the energy consumption is less, which is considered to be an effective way for the purification of silicon.