Abstract: producing 1000 MT/yr. This process for preparing semiconductor-grade silicon in the EPSDU from metallurgical-grade (M-G) silicon is based on a well-integrated arrangement of purification steps that provides a cost-effective process system. The three basic steps entail converting M-G silicon to trichlorosilane, redistributing the trichlorosilane to produce silane, and thermally decomposing the silane to form amorphous silicon powder. The powder is then melted and the molten silicon is cast to polycrystalline for subsequent use in fabricating solar cells. Progress is reported in detail. (WHK)