A new fractional melting (FM) process that uses centrifugal force to separate the liquid from the cake (liquid + solid) was developed for refining metallurgical grade Si. The behavior of the solute and the refining mechanism during the FM process were studied using scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). During the FM, the solutes migrated very quickly and aggregated at seemingly disordered locations, where they subsequently melted before the silicon bulk matrix melted.