Methods for separating iron ions from aluminum ions
There are provided methods for separating iron ions from aluminum ions. For example, the methods can comprise providing a basic aqueous composition comprising said iron ions and said aluminum ions and having a pH of about 10.5 to about 13 and a temperature of about 50 ° C. to about 150 ° C.; reacting said basic aqueous composition with hematite so as to promote, catalyze and/or enhance formation of hematite and to obtain a liquid phase comprising said aluminum ions and a solid phase comprising said so-formed hematite generated with said iron ions; and separating said liquid phase from said solid phase.
1. A method for separating iron ions from aluminum ions contained in a basic aqueous composition, said method comprising :
providing a basic aqueous composition comprising said iron ions and said aluminum ions and having a pH of about 10.5 to about 13 and a temperature of about 50 ° C. to about 150 ° C.;
reacting said basic aqueous composition with hematite so as to promote, catalyze and/or enhance formation of hematite and to obtain a liquid phase comprising said aluminum ions and a solid phase comprising said so-formed hematite generated with said iron ions; and
separating said liquid phase from said solid phase.
2. The method of claim 1 , wherein said method further comprises precipitating said aluminum ions from said liquid phase by adjusting pH of said liquid phase to a value of about 7 to about 11.
3. The method of claim 1 , wherein said method further comprises precipitating said aluminum ions from said liquid phase by adjusting the pH of said liquid phase to a value of about 8 to about 10.5.
4. The method of claim 1 , wherein said method further comprises precipitating said aluminum ions from said liquid phase by adjusting pH of said liquid phase to a value of about 9 to about 10.
5. The method of claim 1 , wherein said method further comprises precipitating said aluminum ions from said liquid phase by adjusting pH of said liquid phase to a value of about 9.2 to about 9.8.
6. The method of claim 5 , wherein said method further comprises adding a precipitating agent effective for facilitating precipitation of said aluminum ions.
7. The method of claim 1 , wherein said basic aqueous composition, before being reacted with said hematite, comprises at least one precipitate that comprises Fe(OH) 3 , Fe(OH) 2 , or a mixture thereof.
8. The method of claim 1 , wherein said basic aqueous composition has a temperature of about 50 ° C. to about 70 ° C.
9. The method of claim 1 , wherein said basic aqueous composition has a temperature of about 70 ° C. to about 100 ° C.
10. The method of claim 1 , wherein said basic aqueous composition has a pH of about 10.8 to about 11.8.
11. The method of claim 1 , wherein said basic aqueous composition has a pH of about 11.5 to about 12.5.
12. The method of claim 1 , wherein about 0.5 to about 25 g hematite are reacted per liter of said basic aqueous composition.
13. The method of claim 1 , wherein hematite is added at a molar ratio hematite / total amount of iron contained in the basic aqueous composition of about 0.01 to about 0.1.
14. The method of claim 1 , wherein said basic aqueous composition is reacted with said hematite by at least substantially maintaining said basic aqueous composition at said temperature.
15. A method for separating iron from aluminum contained in a basic aqueous composition, said method comprising :
reacting said basic aqueous composition comprising said iron and said aluminum with hematite under conditions suitable for at least partially converting said iron into hematite in the form of a precipitate, thereby obtaining a liquid phase and a solid phase, said conditions suitable for at least partially converting said iron into hematite in the form of a precipitate comprises reacting said basic aqueous composition with hematite at a pH of about 10.5 to about 13;
separating said liquid phase from said solid phase; and
precipitating aluminum ions from said liquid phase by adjusting pH of said liquid phase to a value of about 7 to about 11.
16. The method of claim 15 , wherein said method further comprises precipitating said aluminum ions from said liquid phase by adjusting pH of said liquid phase to a value of about 9 to about 10.
17. The method of claim 15 , wherein said hematite is reacted with said basic aqueous composition under agitation.
18. The method of claim 15 , wherein said conditions suitable for at least partially converting said iron into hematite in the form of a precipitate comprises reacting said basic aqueous composition with hematite at a temperature of about 50 ° C. to about 150 ° C.
19. The method of claim 15 , wherein said conditions suitable for at least partially converting said iron into hematite in the form of a precipitate comprises reacting said basic aqueous composition with hematite at a pH of about 11.5 to about 12.5; and comprises reacting about 0.25 to about 25 g of hematite per liter of said basic aqueous composition.
20. The method of claim 15 , wherein said conditions suitable for at least partially converting said iron into hematite in the form of a precipitate comprises reacting said basic aqueous composition with hematite at a pH of about 10.8 to about 11.8; and comprises reacting about 1 to about 20 g of hematite per liter of said basic aqueous composition.