Method For Recovering Lithium

Abstract: The present invention relates to a method for recovering lithium and, more specifically, to a method for recovering lithium, the method comprising the steps of: (a) dissolving a positive electrode material powder, obtained from a positive electrode of a waste lithium ion battery, having an olivine structure in an acetic acid aqueous solution to prepare a solution; (b) adding the solution with an aqueous hydrogen peroxide (H2O2) solution to obtain a leachate containing dissolved lithium and a leaching residue; (c) separating the leachate from the leaching residue; and (d) concentrating the leachate, wherein step (b) is performed at 45 to 65°C, the acetic acid in step (a) is used in an amount of 0.8 to 1.2 mol per 1 mol of positive electrode active material in the positive active material powder, and the hydrogen peroxide in step (b) is used in an amount of 0.4 to 0.6 mol per 1 mol of positive electrode active material in the positive electrode material powder. According to the present invention, a positive electrode material having an olivine structure is selectively leached only with lithium in a predetermined temperature range by using an oxidizing agent in a weakly acidic acetic acid aqueous solution, thereby recovering lithium at a high yield. Furthermore, FePO4 is preserved as the leaching residue and is reused as a raw material for lithium iron phosphate, whereby the productivity and cost-efficiency are greatly improved and waste water treatment is not needed, thus providing an eco-friendly method for recovery of lithium.

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