Manufacturing method of high purity lithium phosphate from the waste liquid of the exhausted lithium-ion battery

A method of manufacturing high-purity lithium phosphate by using a lithium waste liquid of a wasted battery, comprising steps of:

• (a) passing the lithium waste liquid through active carbon to remove organic materials;
• (b) adding a soluble phosphate or an aqueous solution of the soluble phosphate with 0.9 to 1.2 molar equivalents with respect to a concentration of lithium existing in the lithium waste liquid to the lithium waste liquid from which the organic materials are removed and adding alkali or an aqueous solution of the alkali to produce a mixed solution of phosphate and lithium waste liquid of which pH is in a range of 13 to 13.9;
• (c) reacting the mixed solution of phosphate and lithium waste liquid in a temperature range of 50 to 100° C. for 30 to 120 minutes, and after that, performing first solid liquid separation to produce lithium phosphate which is precipitated in a solid state;
• (d) adding water of which weight is 5 to 20 times the weight of the lithium phosphate to the produced lithium phosphate and adding an acid or an aqueous solution of the acid to produce a lithium phosphate aged solution of which pH is in a range of 7 to 11 and stirring the lithium phosphate aged solution at the room temperature for 30 minutes or more to age the lithium phosphate;
• (e) adding an aqueous solution of lithium hydroxide with a molar equivalent of the added amount of the acid to the stirred lithium phosphate aged solution to produce a lithium phosphate precipitated solution of which pH is in a range of 11.5 to 13.5 and stirring the lithium phosphate precipitated solution in a temperature range of 50 to 100° C. for 20 minutes or more to precipitate high-purity lithium phosphate;
• and
• (f) cleaning and drying the separated high-purity lithium phosphate.