Method for treating sulfide-free minerals

Abstract

The present invention provides a method of producing metal oxide(s) by sulfatizing a sulfide-free ore and/or concentrate comprising the steps of providing a sulfide-free ore and/or concentrate comprising sulfide-free mineral(s); and contacting the sulfide-free ore and/or concentrate with gaseous SO 3 for sulfatizing the sulfide-free mineral(s) thereby forming metal sulfate(s) and metal oxide(s).

1 . A method of producing metal oxide(s) by sulfatizing a sulfide-free ore and/or concentrate comprising:
 (o) providing a sulfide-free ore and/or concentrate comprising sulfide-free mineral(s); and   (a) contacting the sulfide-free ore and/or concentrate with gaseous SO 3  for sulfatizing the sulfide-free mineral(s) thereby forming metal sulfate(s) and metal oxide(s).   
     
     
         2 . The method as claimed in  claim 1 , wherein the sulfide-free ore and/or concentrate is selected from the group consisting of sulfide-free ores, sulfide-free concentrates, sulfide-free oxides, sulfide-free hydroxides, sulfide-free silicates, and any mixtures thereof, preferably from sulfide-free ores and/or concentrates comprising borate minerals and/or iron oxides. 
     
     
         3 . The method as claimed in  claim 1 , wherein the sulfide-free mineral is contacted with SO 3  in a fluidized bed reactor (FB), circulating fluidized bed reactor (CFB) or annular fluidized bed reactor (AFB). 
     
     
         4 . The method as claimed in  claim 1 , wherein the SO 3  used in step (a) is produced in situ from sulfur. 
     
     
         5 . The method as claimed in  claim 1 , wherein the SO 3  used in step (a) is produced in situ from sulfur dioxide (SO 2 ). 
     
     
         6 . The method as claimed in  claim 1 , wherein the SO 3  used in step (a) is produced by combining sulfur with oxygen to form sulfur dioxide and further catalytically converting the sulfur dioxide into sulfur trioxide. 
     
     
         7 . The method as claimed in  claim 6 , wherein sulfur trioxide (SO 3 ) is produced in separate units ahead of the sulfatization reactor. 
     
     
         8 . The method as claimed in  claim 4 , wherein the temperature of step (a) is from 700 to 1200° C., preferably from 800 to 1000° C. 
     
     
         9 . The method as claimed in  claim 5 , wherein the temperature of step (a) is from 400 to 800° C., preferably from 500 to 700° C. 
     
     
         10 . The method as claimed in  claim 6 , wherein the temperature of step (a) is from 200 to 700° C., more preferably from 300 to 630° C. 
     
     
         11 . The method as claimed in  claim 1 , wherein step (a) is performed under pressure from atmospheric pressure 1 to 3 bar, preferably from 1.2 to 1.8 bar. 
     
     
         12 . The method as claimed in  claim 1 , wherein the method further comprises:
 (b) separating unreacted gaseous SO 3  from the formed metal sulfate(s) and metal oxide(s).   
     
     
         13 . A method as claimed in  claim 1 , wherein the method further comprises:
 (c) leaching the formed metal sulfate(s) and metal oxide(s) in an aqueous leach liquor thereby extracting the metal oxide(s) into the aqueous leach liquor; and   (d) performing a solid-liquid separation for separating the metal sulfate(s) remaining in solid state from the dissolved metal oxide(s).   
     
     
         14 . A method as claimed in  claim 1 , wherein the method further comprises:
 (c) leaching the formed metal sulfate(s) and metal oxide(s) in an aqueous leach liquor thereby extracting the metal sulfate(s) into the aqueous leach liquor; and   (d) performing a solid-liquid separation for separating the metal oxide(s) remaining in solid state from the dissolved metal sulfate(s).   
     
     
         15 . The method claimed in  claim 14 , wherein the aqueous leach liquor is raffinate, spent acid, or water, preferably water. 
     
     
         16 . The method as claimed in  claim 1 , wherein the sulfide-free ore and/or concentrate is selected from the group consisting of ores and/or concentrates comprising solid sulfide-free minerals containing one or more value elements selected from the group consisting of Cu, Co, Ni, Fe, Mn, Zn, U, Al, Ti, In, Cr, V, Ag, Cd, Zr, Hg, La, Bi, and Sb, in particular borate minerals such as colemanite, ulexite, kernite or borax. 
     
     
         17 . The method as claimed in  claim 7 , wherein the temperature of step (a) is from 200 to 700° C., more preferably from 300 to 630° C. 
     
     
         18 . The method claimed in  claim 13 , wherein the aqueous leach liquor is raffinate, spent acid, or water, preferably water.