Patent ID: 8298502

Claim:
A preparation method of lithium carbonate, comprising: a first step of providing a cleaning solution, and extracting nickel and lithium into an organic phase by solvent extraction, cleaning the organic phase with a sulfuric acid cleaning solution containing nickel, wherein lithium in the organic phase is transferred to the sulfuric acid cleaning solution, thereby obtaining a post-cleaning solution where lithium is enriched; a second step of extracting residual nickel from the post-cleaning solution obtained in the first step by solvent extraction with an organic solvent from the post-cleaning solution, while controlling a pH of the post-cleaning solution by adding an alkaline agent; and a third step of precipitating and recovering lithium carbonate by injecting carbon dioxide gas or adding other carbonation agents, while controlling the pH of the post-cleaning solution by adding a second alkaline agent, thereby recovering lithium carbonate.