METHOD FOR PREPARING BATTERY-GRADE GRAPHITE BY USING MIXED WASTE OF POSITIVE AND NEGATIVE ELECTRODE MATERIALS OF FAILED LITHIUM-ION BATTERY AS RAW MATERIAL

Preparing battery-grade graphite including: 1) placing mixed waste electrode materials of a failed lithium-ion battery in a muffle furnace, and performing low-temperature roasting surface modification in an air atmosphere yielding a powder; 2) forming a slurry of the powder, placing the slurry in a flotation machine, and after stirring the slurry, adding a collector and a foaming agent, obtaining a foam product rich in negative electrode graphite) and an ore slurry product rich in positive electrode material) by flotation separation; 3) after filtering and drying the foam product obtained in step (2), performing weak acid washing, obtaining a leached liquid and a leached residue after filtering, and obtaining negative electrode graphite after drying the leached residue; and 4) after filtering and drying the negative electrode graphite of step (3), placing the negative electrode graphite in a high-temperature graphitization furnace and performing oxygen-free heating, to obtain a regenerated graphite product.