Method of purifying 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 comprising less than about 0.55 ppmw boron.

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 at least about 200 ppmw metal additive is employed, relative to the aluminum.

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

5. The method of claim 1 , wherein the aluminum in step (a) comprises at least about 0.55 ppmw boron.

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

7. 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.

8. 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.

9. 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.

10. 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.

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

12. The method of claim 1 , wherein the step of forming the molten liquid occurs at a temperature of about 650° C.