Preparation method of lithium carbonate from lithium-ion secondary battery recovered material

Preparation of lithium carbonate, as part of a lithium-ion battery recovering process, comprising: a first step of cleaning an organic phase containing nickel and lithium, prepared by a solvent extraction, by use of a sulfuric acid solution containing nickel and enriching lithium in the cleaning solution; a second step of extracting residual nickel only by an organic solvent from a post-cleaning solution in which the lithium is enriched; and a third step of controlling the pH of the post-extraction solution containing the lithium by ammonia water or lithium hydroxide.