Patent ID: 8801855

Claim:
A process for obtaining silicon crystals from silicon powder, comprising: separating a silicon powder from a slurry; treating the separated silicon powder with acid treatment, vacuum melting, magnetic separation, drying or a combination thereof to provide a treated silicon powder; contacting the treated silicon powder with a solvent metal, to provide a mixture containing silicon; melting the silicon under submersion by feeding the silicon powder into a vortex within the solvent metal using a rotary degasser, rotary furnace, molten metal pump or induction currents, to provide a first molten liquid; contacting the first molten liquid with a first gas, to provide dross and a second molten liquid; separating the dross and the second molten liquid; and cooling the second molten liquid approximately homogenously to provide fractional crystallization to form first silicon crystals and a first mother liquid; and separating the first silicon crystals and the first mother liquid; wherein the silicon that is obtained from the last step of the process is used to make solar cells.