Patent ID: 9255011
Filing Date: 2016-02-09
CPC Classification: C01D

Claim Text:
1. A method for producing lithium carbonate, the method comprising: a desulfurizing step of adding a desulfurizing agent containing a calcium compound to a lithium-containing brine as a raw material, and removing sulfate ion contained in the brine as gypsum, thereby obtaining a desulfurized brine; evaporatively concentrating the desulfurized brine, and removing crystallized matters therefrom through solid-liquid separation, thereby obtaining a primarily concentrated brine; subjecting the primarily concentrated brine to electrodialysis by a monovalent ion-permselective ion exchange membrane, thereby obtaining a secondarily concentrated brine; evaporatively concentrating again the secondarily concentrated brine, and removing crystallized matters therefrom through solid-liquid separation, thereby obtaining a tertiary concentrated brine; a carbonation step of introducing carbon dioxide gas obtained by calcining limestone to the tertiary concentrated brine in the presence of ammonia, thereby depositing lithium carbonate crystals; and recovering the lithium carbonate crystals through solid-liquid separation.