METHOD TO PURIFY ALUMINUM AND USE OF PURIFIED ALUMINUM TO PURIFY SILICON

1 . A method for purifying aluminum, the method comprising:

(a) forming a molten liquid from aluminum and a metal additive selected from at least one of titanium, vanadium, zirconium, and chromium;

(b) allowing impurities to form in the molten liquid, wherein the impurities comprise a reaction product of the metal additive and boron;

(b) optionally removing at least a portion of the impurities from the molten liquid;

(d) cooling the molten liquid to form solidified aluminum; and

(e) optionally removing a portion of the solidified aluminum comprising at least a portion of the impurities;

wherein at least one of the optional steps is carried out, to provide purified aluminum.

2 . The method of claim 1 , wherein at least some boron is removed, such that the purified aluminum contains less boron than the aluminum in step (a).

3 . The method of claim 1 , wherein the purified aluminum comprises less than about 0.55 ppmw boron.

4 - 6 . (canceled)

7 . The method of claim 1 , wherein at least about 200 ppmw metal additive is employed, relative to the aluminum.

8 - 9 . (canceled)

10 . The method of claim 1 , wherein metal additive comprises titanium.

11 . The method of claim 1 , wherein the aluminum in step (a) comprises at least about 0.40 ppmw boron.

12 . (canceled)

13 . The method of claim 1 , wherein the impurities that comprise a reaction product of metal additive and boron comprise titanium diboride (TiB 2 ).

14 - 16 . (canceled)

17 . The method of claim 1 , wherein the metal additive is added to the aluminum in step (a), is added to the molten liquid, or a combination thereof

18 - 19 . (canceled)

20 . The method of claim 1 , wherein the optional step of removing the at least a portion of the impurities from the molten liquid is not carried out.

21 . (canceled)

22 . The method of claim 1 , wherein the optional step of removing a portion of the solidified aluminum comprising at least a portion of the impurities is not carried out.

23 . The method of claim 1 , wherein the optional step of removing the at least a portion of the impurities from the molten liquid is carried out, and the optional step of removing a portion of the solidified aluminum comprising at least a portion of the impurities is carried out.

24 . The method of claim 1 , which is carried out two or more times.

25 . A method for purifying silicon, the method comprising:

(a) forming a molten liquid from silicon and aluminum, wherein the aluminum comprises less than about 0.55 ppmw boron;

(b) cooling the molten liquid, to form silicon crystals and a mother liquor; and

(c) separating the silicon crystals and the mother liquor.

26 - 27 . (canceled)

28 . The method of claim 25 , wherein the aluminum comprises less than about 0.10 ppmw boron.

29 . The method of claim 25 , wherein the silicon crystals comprise less than about 0.40 ppmw boron.

30 . (canceled)

31 . The method of claim 25 , wherein the silicon crystals comprise about 0.20 ppmw boron.

32 . The method of claim 25 , wherein in step (a), the silicon is metallurgical grade (MG) silicon.

33 . The method of claim 25 , wherein in step (a), the silicon is employed in about 20 wt. % to about 50 wt. %.

34 - 37 . (canceled)

38 . The method of claim 25 , wherein the silicon crystals comprise silicon in at least about 65 wt. %.

39 . The method of claim 25 , which is carried out two or more times.