Process for extracting aluminum from aluminous ores

Abstract

There is provided a method for extracting aluminum ions from argillite. The process comprises leaching the argillite with an acid such as HCl so as to obtain a composition comprising the aluminum ions and iron ions; at least partially removing the iron ions from the composition by substantially selectively precipitating the iron ions by adding a base and at least partially removing the precipitated iron ions so as to obtain an Al-rich composition; and optionally purifying the Al-rich composition by adding a base for substantially selectively precipitating the aluminum ions, by means of a hollow fiber membrane, or by a liquid-liquid extraction.

1 . A process for extracting aluminum ions from argillite, said process comprising:
 leaching said argillite with HCl at a pressure of about 150 KPa to about 850 KPa so as to obtain a composition comprising said aluminum ions and iron ions;   at least partially removing said iron ions from said composition by substantially selectively precipitating at least a portion of said iron ions at a pH of about 3 to about 6 by reacting said composition with a base and at least partially removing said precipitated iron ions so as to obtain an Al-rich composition; and   optionally purifying said Al-rich composition by:
 substantially selectively precipitating said aluminum ions; 
 by means of a hollow fiber membrane; or 
 by means of a liquid-liquid extraction. 
   
     
     
         2 . (canceled) 
     
     
         3 . The process of  claim 1 , wherein said argillite is leached with HCl at a temperature of at least 90° C. 
     
     
         4 . The process of  claim 1 , wherein said argillite is leached with HCl at a temperature of about 100° C. to about 110° C. 
     
     
         5 . The process of  claim 1 , wherein said HCl has a concentration of about 6 M or about 12 M. 
     
     
         6 . (canceled) 
     
     
         7 . The process of  claim 1 , wherein said process comprises:
 leaching said argillite with HCl at a pressure of about 150 KPa to about 850 KPa so as to obtain a leachate comprising said aluminum ions and said iron ions, and a solid residue;   separating said leachate from said solid residue;   at least partially removing said iron ions from said leachate by substantially selectively precipitating said at least a portion of said iron ions by reacting said base with said leachate and removing a so-formed precipitate, so as to obtain said Al-rich composition; and   purifying said Al-rich composition by substantially selectively precipitating said aluminum ions by reacting said composition with an acid or a base, and by recovering said precipitated aluminum ions.   
     
     
         8 . The process of  claim 1 , wherein said process comprises:
 leaching said argillite with HCl at a pressure of about 150 KPa to about 850 KPa so as to obtain a leachate comprising said aluminum ions and said iron ions, and a solid residue;   separating said leachate from said solid residue;   at least partially removing said iron ions from said leachate by substantially selectively precipitating said at least a portion of said iron ions by reacting said base with said leachate and removing a so-formed precipitate, so as to obtain said Al-rich composition; and   purifying said Al-rich composition by means of a hollow fiber membrane, or by a liquid-liquid extraction.   
     
     
         9 . The process of  claim 1 , wherein said process comprises:
 leaching said argillite with HCl at a pressure of about 150 KPa to about 850 KPa so as to obtain a leachate comprising said aluminum ions and said iron ions, and a solid residue;   separating said leachate from said solid residue;   at least partially removing said iron ions from said leachate by substantially selectively precipitating said at least a portion of said iron ions by reacting said base with said leachate and removing a so-formed precipitate, so as to obtain said Al-rich composition; and   purifying said Al-rich composition by substantially selectively precipitating said aluminum ions and recovering said precipitated aluminum ions.   
     
     
         10 . The process of  claim 1 , wherein said Al-rich composition is purified by complexing said aluminum ions with an extracting agent so as to obtain a complex, separating said complex from said composition and precipitating said aluminum ions. 
     
     
         11 . The process of  claim 10 , wherein said extracting agent is bis(2,4,4-trimethylpentyl)phosphinic acid. 
     
     
         12 - 19 . (canceled) 
     
     
         20 . The process of  claim 1 , wherein said iron is at least partially removed from said argillite by substantially selectively precipitating said at least a portion of said iron ions at a pH of about 3 to about 5 by adding said base. 
     
     
         21 . The process of  claim 1 , wherein said iron is at least partially removed from said argillite by substantially selectively precipitating said at least a portion of said iron ions at a pH of about 3 to about 4 by adding said base. 
     
     
         22 - 23 . (canceled) 
     
     
         24 . The process of  claim 1 , wherein said iron is at least partially removed from said argillite by substantially selectively precipitating said at least a portion of said iron ions at a pH of about 4 to about 5 by adding said base. 
     
     
         25 . (canceled) 
     
     
         26 . The process of  claim 1 , wherein said Al-rich composition is purified by adding a base for substantially selectively precipitating said aluminum ions at a pH of about 5 to about 6 and recovering said precipitated aluminum ions. 
     
     
         27 - 28 . (canceled) 
     
     
         29 . A process for extracting aluminum ions from an aluminosilicate ore, said process comprising:
 leaching said aluminosilicate ore with an acid so as to obtain a composition comprising said aluminum ions and iron ions;   at least partially removing said iron ions from said composition by substantially selectively precipitating at least a portion said iron ions at a pH of about 3 to about 5 by reacting said composition with a base and at least partially removing said precipitated iron ions so as to obtain an Al-rich composition; and   purifying said Al-rich composition by:
 substantially selectively precipitating said aluminum ions at a pH of about 5 to about 6 by reacting said Al-rich composition with a base and recovering said precipitated aluminum ions; or 
 by means of a hollow fiber membrane. 
   
     
     
         30 . A process for producing alumina comprising
 obtaining aluminum ions by means of a process as defined in  claim 1 ; and   converting said aluminum ions into alumina.   
     
     
         31 . (canceled) 
     
     
         32 . A process for producing aluminum comprising
 obtaining alumina by means of a process as defined in  claim 30 ; and   converting said alumina into aluminum.   
     
     
         33 . The process of  claim 1 , wherein said leaching with HCl is carried out at a pressure of about 150 KPa to about 750 KPa. 
     
     
         34 . The process of  claim 10 , wherein said leaching with HCl is carried out at a pressure of about 200 KPa to about 600 KPa. 
     
     
         35 . The process of  claim 20 , wherein said leaching with HCl is carried out at a pressure of about 250 KPa to about 500 KPa. 
     
     
         36 . A process for extracting aluminum ions from an aluminosilicate ore, said process comprising:
 leaching said aluminosilicate ore with an acid so as to obtain a composition comprising said aluminum ions and iron ions;   at least partially removing said iron ions from said composition by precipitating at least a portion said iron ions so as to obtain an Al-rich composition; and   purifying said Al-rich composition by:
 substantially selectively precipitating said aluminum ions at a pH of about 5 to about 6 by reacting said Al-rich composition with a base and recovering said precipitated aluminum ions; or 
   by means of a hollow fiber membrane.