LINING FOR SURFACES OF A REFRACTORY CRUCIBLE FOR PURIFICATION OF SILICON MELT AND METHOD OF PURIFICATION OF THE SILICON MELT USING THAT CRUCIBLE
A crucible for containing molten silicon comprises at least one refractory material having at least one inner surface defining an interior for receiving a molten silicon mixture, and a lining deposited onto the inner surface, the lining comprising colloidal alumina. A method for silicon purification comprises contacting a first silicon with a solvent metal comprising aluminum, sufficient to provide a first mixture, melting the first mixture in an interior of a melting crucible to provide a molten silicon mixture, the melting crucible comprising at least one refractory material having an inner surface defining the interior of the melting crucible, coating at least a portion of the inner surface of the melting crucible with a lining comprising colloidal alumina prior to melting first mixture, cooling the molten silicon mixture, sufficient to form recrystallized silicon crystals and a mother liquor, and separating the final recrystallized silicon crystals and the mother liquor.
1 . A crucible for containing a molten silicon mixture, the crucible comprising:
at least one refractory material having at least one inner surface defining an interior for receiving a molten silicon mixture;
a lining deposited onto the inner surface, the lining comprising colloidal alumina.
2 . (canceled)
3 . The crucible of claim 1 , wherein the lining prevents contamination of the molten silicon from at least one of boron and phosphorous contained within the interior of the at least one refractory material.
4 . The crucible of claim 1 , wherein the colloidal alumina comprises alumina particles suspended in water, the alumina particles having a size between 20 nanometers and 50 nanometers, inclusive.
5 . The crucible of claim 1 , wherein the lining has a thickness of between 2 millimeters and 10 millimeters, inclusive.
6 . The crucible of claim 1 , wherein the at least one refractory material comprises alumina.
7 . The crucible of claim 1 , wherein the lining further comprises silicon carbide particles bound by the colloidal alumina.
8 . The crucible of claim 7 , wherein the silicon carbide particles have a size of less than about 3.5 millimeters.
9 . (canceled)
10 . A method for the purification of silicon, the method comprising:
contacting a first silicon with a solvent metal comprising aluminum, to provide a first mixture;
melting the first mixture in an interior of a melting crucible to provide a molten silicon mixture, the melting crucible comprising at least one refractory material having an inner surface defining the interior of the melting crucible;
coating at least a portion of the inner surface of the melting crucible with a lining comprising colloidal alumina prior to melting the first mixture;
cooling the molten silicon mixture, to form recrystallized silicon crystals and a mother liquor; and
separating the final recrystallized silicon crystals and the mother liquor.
11 . (canceled)
12 . The method of claim 10 , wherein the lining prevents contamination of the molten silicon mixture from at least one of boron and phosphorous from the at least one refractory material.
13 . The method of claim 10 , wherein the colloidal alumina comprises alumina particles suspended in water, the alumina particles have a size between 20 nanometers and 50 nanometers, inclusive.
14 . The method of claim 10 , wherein the lining has a thickness of between 2 millimeters and 10 millimeters, inclusive.
15 . The method of claim 10 , wherein the lining further comprises silicon carbide particles bound by the colloidal alumina.
16 . The method of claim 15 , wherein the silicon carbide particles have a size of less than about 3.5 millimeters.
17 . The method of claim 10 , wherein the at least one refractory material comprises alumina.
18 . A method for the purification of silicon, the method comprising:
contacting a first silicon with a first solvent metal, to provide a first mixture;
coating at least a portion of a first inner surface of a first refractory of a first melting crucible with a first lining comprising colloidal alumina;
melting the first mixture in an interior of the first melting crucible to provide a first molten silicon mixture;
cooling the first molten silicon mixture, to form first silicon crystals and a first mother liquor;
separating the first silicon crystals and the first mother liquor;
contacting the first silicon crystals with a second solvent metal, to provide a second mixture;
coating at least a portion of a second inner surface of a second refractory of a second melting crucible with a second lining comprising colloidal alumina;
melting the second mixture in an interior of the second melting crucible to provide a second molten silicon mixture;
cooling the second molten silicon mixture, to form second silicon crystals and a second mother liquor; and
separating the second silicon crystals and the second mother liquor.
19 . The method of claim 18 , wherein at least a portion of the first solvent metal comprises at least one of: at least a portion of the first mother liquor and at least a portion of the second mother liquor.
20 . The method of claim 18 , wherein at least a portion of the second solvent metal comprises at least one of at: least a portion of the first mother liquor and at least a portion of the second mother liquor.
21 . The method of claim 18 , further comprising:
contacting the second silicon crystals with a third solvent metal, to provide a third mixture;
coating at least a portion of a third inner surface of a third refractory of a third melting crucible with a third lining comprising colloidal alumina;
melting the third mixture in an interior of the third melting crucible to provide a third molten silicon mixture;
cooling the third molten silicon mixture, to form third silicon crystals and a third mother liquor; and
separating the third silicon crystals and the third mother liquor.
22 - 24 . (canceled)