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US 2011/0236290 A1Published application
Method for processing silicon powder to obtain silicon crystals
Assignee6N Silicon Inc.
InventorScott Nichol
Life of this patent
Estimating the term…
Abstract
Embodiments of the present invention relate to a process for obtaining silicon crystals from silicon. The method includes contacting silicon powder with a solvent metal to provide a mixture containing silicon, melting the silicon under submersion 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, cooling the second molten liquid to form first silicon crystals and a first mother liquid and separating the first silicon crystals and the first mother liquid.
Claims20
A process for obtaining silicon crystals from silicon powder, comprising:
- contacting silicon powder with a solvent metal, to provide a mixture containing silicon, wherein the solvent metal is selected from the group consisting of silicon, molten silicon, copper, tin, zinc, antimony, silver, bismuth, aluminum, cadmium, gallium, indium, magnesium, lead, an alloy thereof, and combinations thereof;
- 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;
- cooling the second molten liquid approximately homogenously to provide fractional crystallization to form first silicon crystals and a first mother liquid;
- separating the first silicon crystals and the first mother liquid;
- melting the first silicon crystals, to provide a first molten bath;
- contacting the first molten bath with a second gas, wherein the second gas comprises oxygen, water, a hydrogen and inert gas mixture, or a combination thereof;
- directionally solidifying the first molten bath, to provide second silicon crystals;
- heating the second silicon crystals, to provide a second molten bath;
- and
- directionally solidifying the second molten bath to provide purified silicon;
- wherein the purified silicon that is obtained from the last step of the process is used to make solar cells.
10 more elements
A process for obtaining silicon crystals from silicon powder, comprising:
- contacting silicon powder with a solvent metal to provide a mixture containing silicon, wherein the solvent metal is selected from the group consisting of silicon, molten silicon, copper, tin, zinc, antimony, silver, bismuth, aluminum, cadmium, gallium, indium, magnesium, lead, an alloy thereof, and combinations thereof;
- melting the silicon under submersion, 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;
- cooling the second molten liquid approximately homogenously to provide fractional crystallization to form first silicon crystals and a first mother liquid;
- separating the first silicon crystals and the first mother liquid;
- washing the first silicon crystals with acid;
- melting the first silicon crystals, to provide a first molten bath;
- contacting the first molten bath with a second gas, wherein the second gas comprises oxygen, water, a hydrogen and inert gas mixture, or a combination thereof;
- directionally solidifying the first molten bath, to provide second silicon crystals;
- heating the second silicon crystals, to provide a second molten bath;
- and
- directionally solidifying the second molten bath to provide purified silicon.
10 more elements
A process for obtaining silicon crystals from silicon powder, comprising:
- contacting silicon powder with a solvent metal to provide a mixture containing silicon, wherein the solvent metal is selected from the group consisting of silicon, molten silicon, copper, tin, zinc, antimony, silver, bismuth, aluminum, cadmium, gallium, indium, magnesium, lead, an alloy thereof, and combinations thereof;
- melting the silicon under submersion to provide a first molten liquid;
- contacting the first molten liquid with an initial gas;
- 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;
- cooling the second molten liquid approximately homogenously to provide fractional crystallization to form first silicon crystals and a first mother liquid;
- separating the first silicon crystals and the first mother liquid;
- melting the first silicon crystals, to provide a first molten bath;
- contacting the first molten bath with a second gas, wherein the second gas comprises oxygen, water, a hydrogen and inert gas mixture, or a combination thereof;
- directionally solidifying the first molten bath, to provide second silicon crystals;
- heating the second silicon crystals, to provide a second molten bath;
- and
- directionally solidifying the second molten bath to provide purified silicon
10 more elements
Dependencies are inferred from the claim text.