Production of low-cost solar grade (SoG) silicon feedstock

A simple refining process of blowing moist gases over molten silicon removed high segregation impurities, especially B and P, and reduced other impurities. Using this process with heavily B-doped (Hi-B) silicon scrap from the electronic industry will double the feedstock available to the PV industry short term. When the refining process is followed by directional solidification, it can be used for upgrading metallurgical grade (MG) silicon to produce solar grade (SoG) silicon. For the long term, total processing in an MG silicon production plant can result in $10/kg SoG silicon feedstock.