Method for directly and preferentially extracting lithium from waste lithium ion battery monomer

The invention discloses a method for directly and preferentially extracting lithium from a waste lithium ion battery monomer. The method comprises the following steps: carrying out electrified one-time crushing on a waste ternary lithium ion battery monomer in an anaerobic atmosphere, then mixing all crushed materials with a powdery salt compound, carrying out in-situ pyrolysis reduction roasting at a high temperature, immediately leaching the pyrolyzed materials with water, and filtering and separating to obtain a leaching solution and leaching residues. Filtering the leachate through a micro-filtration membrane to remove impurities, and adding sodium carbonate to react to obtain a lithium carbonate product; and separating the leaching residues by a hydrodynamic method to obtain pole powder, a shell pile head and a copper-aluminum foil mixture, drying the copper-aluminum foil mixture, and separating by a color sorting method to obtain copper foil and aluminum foil. According to the method, the lithium-rich s