Processes for preparing lithium carbonate

Abstract

There are provided methods for preparing lithium carbonate. For example, such methods can comprise reacting an aqueous composition comprising lithium hydroxide with CO 2 by sparging the CO 2 the said composition, thereby obtaining a precipitate comprising the lithium carbonate. The methods can also comprise inserting at least a portion of the precipitate into a clarifier and obtaining a supernatant comprising lithium bicarbonate and a solid comprising the lithium carbonate, separating the solid from the supernatant; and heating the supernatant at a desired temperature so as to at least partially convert the lithium bicarbonate into lithium carbonate.

What is claimed is: 
     
         1 . A process for preparing lithium carbonate, said process comprising:
 reacting an aqueous composition comprising lithium hydroxide with CO 2  by sparging said CO 2  into said composition, said sparging being carried out at a pH of about 10 to about 12.5, thereby obtaining a precipitate comprising said lithium carbonate;   inserting at least a portion of said precipitate into a clarifier and obtaining a supernatant comprising lithium bicarbonate and a solid comprising said lithium carbonate, separating said solid from said supernatant; and   heating said supernatant at a temperature of at least about 85° C. so as to at least partially convert said lithium bicarbonate into lithium carbonate.   
     
     
         2 . The process of  claim 1 , wherein said process comprises heating said supernatant at said temperature of at least about 85° C. so as to at least partially convert said lithium bicarbonate into lithium carbonate and precipitate any dissolved lithium carbonate contained therein. 
     
     
         3 . The process of  claim 1 , wherein during said sparging, said pH is at least substantially maintained at a value of about 10 to about 12.5. 
     
     
         4 . The process of  claim 1 , wherein during said sparging, said pH is at least substantially maintained at a value of about 10.5 to about 12.0. 
     
     
         5 . The process of  claim 1 , wherein during said sparging, said pH is at least substantially maintained at a value of about 10.5 to about 11.5. 
     
     
         6 . The process of  claim 1 , wherein during said sparging, said pH is at least substantially maintained at a value of about 10.7 to about 11.3. 
     
     
         7 . The process of  claim 1 , wherein during said sparging, said pH is at least substantially maintained at a value of about 10.8 to about 11.2 or about 10.9 to about 11.1. 
     
     
         8 . The process of  claim 1 , wherein during said sparging, said pH is at least substantially maintained at a value of about 11. 
     
     
         9 . The process of  claim 1 , wherein said supernatant is heated at a temperature of at least about 87° C. 
     
     
         10 . The process of  claim 1 , wherein said supernatant is heated at a temperature of at least about 89° C. 
     
     
         11 . The process of  claim 1 , wherein said supernatant is heated at a temperature of at least about 91° C. 
     
     
         12 . The process of  claim 1 , wherein said supernatant is heated at a temperature of at least about 93° C. 
     
     
         13 . The process of  claim 1 , wherein said supernatant is heated at a temperature of at least about 95° C. 
     
     
         14 . The process of  claim 1 , wherein said supernatant is heated at a temperature of at least about 97° C. 
     
     
         15 . The process of  claim 1 , wherein said supernatant is heated at a temperature of about 85° C. to about 105° C. 
     
     
         16 . The process of  claim 1 , wherein said supernatant is heated at a temperature of about 90° C. to about 100° C. 
     
     
         17 . The process of  claim 1 , wherein said supernatant is heated at a temperature of about 92° C. to about 98° C. 
     
     
         18 . The process of  claim 1 , wherein said supernatant is heated at a temperature of about 93° C. to about 97° C. 
     
     
         19 . The process of  claim 1 , wherein said supernatant is heated at a temperature of about 94° C. to about 96° C. 
     
     
         20 . The process of  claim 1 , wherein said supernatant is heated at a temperature of about 95° C.