LINING FOR SURFACES OF A REFRACTORY CRUCIBLE FOR PURIFICATION OF SILICON MELT AND METHOD OF PURIFICATION OF THE SILICON MELT USING THAT CRUCIBLE(S) FOR MELTING AND FURTHER DIRECTIONAL SOLIDIFICATION
A crucible for molten silicon comprises at least one refractory material having an inner surface and a lining deposited onto the inner surface, the lining comprising colloidal silica. A method for silicon purification comprises melting a first silicon in an interior of a melting crucible to provide a first molten silicon, the melting crucible comprising a first refractory material having at least one first inner surface defining the melting crucible interior, directionally solidifying the first molten silicon in a directional solidification mold to provide a second silicon, the directional solidification mold comprising a second refractory material having at least one second inner surface defining a mold interior, and coating at least a portion of at least one of the first inner surface and the second inner surface with a lining comprising colloidal silica.
1 . A crucible for containing a molten silicon mixture, the crucible comprising:
a body comprising at least one refractory material having at least one inner surface defining an interior for receiving molten silicon; and
a lining deposited onto the inner surface, the lining comprising colloidal silica.
2 . The crucible of claim 1 , wherein the lining further comprises at least one flux material capable of reacting with the molten silicon to form a slag.
3 . The crucible of claim 2 , wherein the flux material comprises at least one of sodium carbonate, calcium oxide, and calcium fluoride.
4 . The crucible of claim 1 , wherein the colloidal silica comprises silica particles suspended in a liquid phase, the silica particles have a size between 10 nanometers and 30 nanometers, inclusive.
5 . The crucible of claim 1 , wherein the lining includes silicon carbide particles bound together by a colloidal silica.
6 . The crucible of claim 4 , wherein the lining is 40%, by weight, silicon carbide and 60%, by weight, colloidal silica.
7 . The crucible of claim 4 , wherein the silicon carbide particles have a size of less than or equal to about 3.5 millimeters.
8 . The crucible of claim 1 , wherein the lining has a thickness of from 2 millimeters to 10 millimeters, inclusive.
9 . The crucible of claim 1 , wherein the at least one refractory material comprises alumina.
10 . The crucible of claim 1 , wherein the crucible is used to form a molten metal containing silicon.
11 . The crucible of claim 1 , wherein the crucible is used as a mold for directional solidification.
12 . A method for the purification of silicon, the method comprising:
melting a first silicon in an interior of a melting crucible to provide a first molten silicon, the melting crucible comprising a first refractory material having at least one first inner surface defining the interior of the melting crucible;
directionally solidifying the first molten silicon in a directional solidification mold to provide a second silicon, the directional solidification mold comprising a second refractory material having at least one second inner surface defining an interior of the directional solidification mold; and
coating at least a portion of at least one of the first inner surface and the second inner surface with a lining comprising colloidal silica.
13 . The method of claim 12 , wherein coating at least a portion of at least one of the first inner surface and the second inner surface with the lining includes coating at least a portion of at least one of the first inner surface and the second inner surface with a lining that further includes silicon carbide particles.
14 . The method of claim 13 , wherein coating at least a portion includes coating with a lining that is 40%, by weight, silicon carbide and 60%, by weight, colloidal silica.
15 . The method of claim 13 , wherein coating at least a portion includes coating with a lining that includes silicon carbide particles with a size of less than or equal to about 3.5 millimeters.
16 . The method of claim 12 , wherein coating at least a portion includes coating with a lining that includes silica particles suspended in a liquid phase, the silica particles have a size between 10 nanometers and 30 nanometers, inclusive.
17 . The method of claim 12 , wherein coating at least a portion includes coating with a lining that has a thickness of between 2 millimeters and 10 millimeters, inclusive.
18 . The method of claim 12 , wherein melting the first silicon in the interior of the melting crucible includes melting in a crucible wherein the first refractory material of the melting crucible comprises alumina.
19 . The method of claim 12 , wherein directionally solidifying the first molten silicon in a directional solidification mold includes directionally solidifying in a mold wherein the second refractory material comprises alumina.
20 . The method of claim 12 , wherein directionally solidifying the first molten silicon in a directional solidification mold includes directionally solidifying in a mold wherein the lining includes two layers including a passive inner layer and an active outer layer.
21 . (canceled)