Upgrading titaniferous materials

Abstract

The application discloses a process for upgrading a titaniferous material by removal of impurities contained in the material especially radionuclides. The process involves heating the titaniferous material to a temperature of less than 1300° C. to form a solid titaniferous phase and a liquid oxide or glassy phase in the presence of a material that promotes the formations of such phases, cooling the product at a rate that maintains the glassy phase in an amorphous state and leaching the solidified material with an acid or an alkali to remove the impurities. Materials that promote the formation of the desired phases include compounds of alkali metals and boron. Examples include borax, caustic soda, soda ash and silica.

1 . A process for upgrading a titaniferous material by removal of impurities which process includes the steps of: 
 (i) heating a titaniferous material to a temperature of less than 1300° C. to produce a solid titaniferous phase and a liquid oxide or glassy phase in the presence of sufficient of compounds which encourage the formation of the liquid oxide or glassy phase;    (ii) cooling the product of step (i) to form a solidified material comprising the titaniferous phase and an impurity bearing phase at a rate sufficient to ensure the susceptibility of the impurity bearing phase to leaching in either an acid or alkaline leachant; and    (iii) leaching the solidified material with an acidic or alkaline leachant to leach at least a portion of the impurities.    
     
     
         2 . A process for upgrading a titaniferous material according to  claim 1  wherein the compounds which encourage the formation of the liquid oxide or glassy phase at a temperature below 1300° C. are compounds of sodium, potassium, lithium, phosphorus silicon or boron.  
     
     
         3 . A process for upgrading a titaniferous mineral according to  claim 2 , wherein the compound of sodium is caustic soda.  
     
     
         4 . A process for upgrading a titaniferous mineral according to  claim 2 , wherein the compound of sodium is sodium carbonate.  
     
     
         5 . A process for upgrading a titaniferous mineral according to  claim 2 , wherein the compounds include borax.  
     
     
         6 . A process for upgrading a titaniferous mineral according to  claim 2 , wherein the compounds comprise a mixture of soda ash and borax.  
     
     
         7 . A process according to  claim 6 , wherein the titaniferous material is heated to a maximum temperature of 1000° C. for a period which avoids substantial reduction to metal of contained iron oxides.  
     
     
         8 . A process according to  claim 7 , wherein the solidified material is leached with water.  
     
     
         9 . A process according to  claim 7 , wherein the solidified material is leached with a recycled solution of leach liquor containing sodium silicate and borax to form a leachate and a residue.  
     
     
         10 . A process according to  claim 9 , wherein the leachate is separated from the residue and the residue is leached with hydrochloric acid having an acid strength in a range from 1 to 20% hydrochloric acid.  
     
     
         11 . A process according to  claim 1  wherein the compounds include compounds which extend the effect of other compounds.  
     
     
         12 . A process according to  claim 11  wherein a compound which extends the effect of other compounds is borax.  
     
     
         13 . A process according to  claim 1  wherein sufficient compounds are present to avoid the formation of titanate phases that are not amenable to subsequent leaching.  
     
     
         14 . A process according to  claim 1  wherein the solidified material is leached under mild conditions.  
     
     
         15 . A process according to  claim 14  wherein the solidified material is leached at atmospheric pressure.  
     
     
         16 . An upgraded titaniferous material produced by the process of any one of  claims 1  to  15 .