Methods for leaching of ores

Abstract

Disclosed and claimed are efficient methods for leaching minerals from ores using an acidic solution such as sulfuric acid. Additional factors which can improve mineral recovery include the use of an alkali metal halide, grinding the ore, addition of a carbon source, and/or adjustment of the temperature at which the process is carried out. Minerals such as titanium, iron, nickel, colbalt, silver and gold may be recovered by the methods of the present invention.

What is claimed is:  
     
         1 . A multi-stage method for recovering titanium and iron from a titanium and iron-bearing mineral feed, said method comprising: 
 (a) contacting said feed material with an acid solution for a period of time sufficient to solubilize said titanium but insufficient to allow said titanium to appreciably precipitate, wherein a pulp and a leach liquor are formed;    (b) separating said pulp from said leach liquor;    (c) contacting said pulp with fresh leach liquor    (d) repeating steps (a) and (b) until all economically feasible titanium is leached; and    (e) recovering, separately, said titanium and said iron from said leach liquors, wherein said solubilization step is carried out at a temperature of about 90° C. to about 105° C.    
     
     
         2 . The method according to  claim 1 , wherein step (a) involves solids of between about 1 percent and about 60 percent on a weight/weight basis.  
     
     
         3 . The method according to  claim 2 , wherein said solids are of a particulate size such that said solids are capable of passing through a 75 micron sieve.  
     
     
         4 . The method according to  claim 1 , wherein said acid is a halide acid.  
     
     
         5 . The method according to  claim 4 , wherein said halide acid is selected from the group consisting of hydrochloric acid and hydrobromic acid.  
     
     
         6 . The method according to  claim 1 , wherein said acid is sulfuric acid.  
     
     
         7 . The method according to  claim 1 , wherein step (a) is carried out in the presence of an alkali metal halide.  
     
     
         8 . The method according to  claim 7 , wherein said alkali metal halide is selected from the group consisting of NaCl, KCl, NaBr and KBr.  
     
     
         9 . The method according to  claim 8 , wherein said alkali metal halide is NaCl.  
     
     
         10 . The method according to  claim 1 , wherein said solubilization step is carried out at a temperature of about 40° C. to about 110° C.  
     
     
         11 . The method according to  claim 1 , wherein said solubilization step is carried out at a temperature of about 90° C. to about 105° C.