Preparation method of high-purity lithium carbonate

The invention relates to a preparation method of high-purity lithium carbonate, which belongs to the technical field of preparation of high-purity lithium carbonate. The invention aims at providing the method for directly preparing 99.99% lithium hydroxide by adopting lithium hydroxide, which is simple in production process. The technical scheme of the invention is as follows: preparing battery level lithium hydroxide monohydrate into solution of Li2O with concentration of 50-90g/L; introducing CO2 gas at the flow rate of 3-5L/s into the lithium hydroxide solution, wherein the flow rate of CO2 is decreased to 2-3L/s when the concentration of Li2O in the solution is decreased to 40g/L; decreasing the flow rate of CO2 to 0.8-1.2L/s when the concentration of Li2O in the solution is decreased to 20g/L; stop introducing the gas when a large number of liquids appear in the solution, and preparing lithium carbonate slurry; and separating the lithium carbonate slurry, washing the solids, drying until moisture is less than 0.1%, finally preparing the lithium carbonate. The battery level lithium hydroxide monohydrate is adopted as raw material, the high-purity lithium carbonate with the purity of 99.99% can be simply and conveniently prepared by adopting the method, and further purification is not required.