Separation of tungsten from ammonium molybdate solutions

Abstract

Disclosed is process for the separation of tungsten from molybdenum and more particularly from ammonium molybdate solutions. The method comprises dissolving technical grade molybdenum trioxide in an aqueous ammonium hydroxide solution and further adding certain metal generating compounds to the aqueous solution thereby generating a tungsten-containing precipitate. Calcium, iron and manganese are the preferred metal generating compounds of the invention. Certain temperature and pH values of the system, as disclosed, are preferred for the precipitation of the tungsten from the ammonia molybdate solution.

What is claimed is: 
     
         1 . A process for the separation of tungsten from molybdenum comprising the steps of
 (a) dissolving a compound containing molybdenum and tungsten in an ammoniacal solution and (b) adding at least one metal ion generating compound to the solution, the metal ion generating compound being selected from calcium, iron and manganese;   wherein a precipitate comprising tungsten is generated.   
     
     
         2 . The process of  claim 1 , wherein the precipitate comprising tungsten is generated in an amount of less than 125 ppm. 
     
     
         3 . The process of  claim 1 , wherein the molybdenum containing compound is technical grade molybdenum trioxide. 
     
     
         4 . The process of  claim 1 , wherein the ammoniacal solution is ammonium hydroxide. 
     
     
         5 . The process of  claim 1 , wherein the calcium ion generating compound is selected from calcium acetate, calcium hydroxide, calcium chloride, and calcium nitrate. 
     
     
         6 . The process of  claim 5 , wherein the temperature of the system is between 10° C. and 50° C. 
     
     
         7 . The process of  claim 1 , wherein the iron ion generating compound is
 selected from ferric sulfate, ferrous molybdate, ferric molybdate, ferric nitrate, and ferric chloride.   
     
     
         8 . The process of  claim 7 , wherein the temperature of the system is between 50° C. and 70° C. 
     
     
         9 . The process of  claim 1 , wherein the manganese ion generating compound is manganous chloride or manganous nitrate. 
     
     
         10 . The process of  claim 9 , wherein the temperature of the system is between 10° C. and 60° C. 
     
     
         11 . The process of  claim 1 , wherein the pH of the system is between 7 and 10.