An efficient method to purify metallurgical grade Si by electromagnetic semi-continuous casting of Al-30Si melt

This paper reported a very simple and energy-saving method to refine metallurgical grade Si (MG-Si) for use in solar cell materials. Refined Si was prepared by using a rotating magnetic field (RMF) to separate the primary Si continuously from hypereutectic Al-30Si melt during semi-continuous casting. Purification testing of the refined Si indicates that the contents of almost all metallic elements can be reduced to the solar grade levels (≤0.1 ppmw) by electromagnetic separation with solidification refining just twice, while those of the non-metallic impurities B and P can be effectively controlled within the acceptable levels (B<0.3 ppmw, P<0.5 ppmw) by solidification refining for three times.