Abstract: Disclosed are a method for removing elemental copper from ternary battery waste and its application. The method comprises the following steps: crushing and screening the ternary battery waste to obtain a powder, and then removing iron by magnetic separation to obtain an iron-removed ternary waste; Adding an alkaline solution to the iron-removed ternary waste to perform an aluminum removal reaction, filtering to obtain a filter slag and aluminum-containing wastewater, washing the filter slag with water and drying to obtain a copper-nickel-cobalt-manganese material. Adding an iron salt solution to the copper-nickel-containing material to perform a leaching process, filtering to obtain a leachate and a nickel-cobalt-manganese waste; adding iron powder to the leachate and stirring to perform a reaction, filtering to obtain a copper residue, washing the copper residue with water and drying to obtain a copper-removed liquid and a sponge copper.