Processes for extracting aluminum from aluminous ores

Abstract

There are provided processes for extracting aluminum ions from aluminous ores and for preparing alumina. Such processes can be used with various types of aluminous ores such as aluminous ores comprising, for example, various types of metals such as Fe, K, Mg, Na, Ca, Mn, Ba, Zn, Li, Sr, V, Ni, Cr, Pb, Cu, Co, Sb, As, B, Sn, Be, Mo, or mixtures thereof.

What is claimed is: 
     
         1 . A process for extracting aluminum ions from an aluminous ore, said process comprising:
 leaching said aluminous ore with an acid to obtain a composition comprising aluminum ions and iron ions;   at least partially removing said iron ions from said composition by substantially selectively precipitating said iron ions at a pH of at least 10 by reacting said composition with a base and at least partially removing said precipitated iron ions, thereby obtaining an Al-rich composition comprising Al 3+  ions; and   purifying said Al 3+  ions.   
     
     
         2 . The process of  claim 2 , wherein said aluminous ore is leached with HCl at a temperature of at least 100° C. 
     
     
         3 . The process of  claim 1 , wherein purifying said Al 3+  ions comprises reacting said Al 3+  ions with HCl. 
     
     
         4 . The process of  claim 3 , wherein said pH is between 10 and 11. 
     
     
         5 . The process of  claim 1 , wherein said Al 3+  ions are purified by substantially selectively precipitating them. 
     
     
         6 . The process of  claim 1 , wherein said pH is about 11.5 to about 12.5. 
     
     
         7 . A process for extracting aluminum ions from an aluminous ore, said process comprising:
 leaching said aluminous ore with HCl to obtain a composition comprising a leachate and a solid residue;   separating said leachate and said solid residue from one another;   at least partially removing iron from said leachate by substantially selectively precipitating iron ions by reacting said leachate with a base and removing a so-formed precipitate, to obtain an Al-rich composition comprising Al 3+  ions; and   purifying said Al 3+  ions.   
     
     
         8 . The process of  claim 7 , wherein said Al 3+  ions are purified by substantially selectively precipitating them. 
     
     
         9 . The process of  claim 7 , wherein said Al 3+  ions are substantially selectively precipitated by reacting said Al-rich composition with a base. 
     
     
         10 . The process of  claim 7 , wherein said Al 3+  ions are substantially selectively precipitated by reacting said Al-rich composition with an acid. 
     
     
         11 . The process of  claim 7 , wherein said iron ions are at least partially removed from said leachate by substantially selectively precipitating them at a pH of at least 10. 
     
     
         12 . The process of  claim 7 , wherein said pH is between 10 and 11. 
     
     
         13 . The process of  claim 7 , wherein said pH is at least 11. 
     
     
         14 . The process of  claim 7 , wherein said pH is about 11.5 to about 12.5. 
     
     
         15 . A process preparing alumina, said process comprising:
 leaching an aluminous ore with HCl to obtain a composition comprising a leachate and a solid residue;   separating said leachate and said solid residue from one another;   at least partially removing iron from said leachate by substantially selectively precipitating iron ions by reacting said leachate with a base and removing a so-formed precipitate, to obtain an Al-rich composition comprising Al 3+  ions;   purifying said Al 3+  ion; and   converting said Al 3+  ions into alumina.   
     
     
         16 . The process of  claim 15 , wherein said Al 3+  ions are substantially selectively precipitated by reacting said Al-rich composition with a base. 
     
     
         17 . The process of  claim 15 , wherein said Al 3+  ions are substantially selectively precipitated by reacting said Al-rich composition with an acid. 
     
     
         18 . The process of  claim 15 , wherein said iron ions are at least partially removed said leachate by substantially selectively precipitating them at a pH of at least 10. 
     
     
         19 . The process of  claim 15 , wherein said pH is between 10 and 11. 
     
     
         20 . The process of  claim 15 , wherein said pH is about 11.5 to about 12.5.