Method for preparing battery positive electrode material by leaching waste lithium batteries with sulfur dioxide gas

The invention discloses a method for preparing a battery positive electrode material by leaching waste lithium batteries with sulfur dioxide gas. The method comprises the steps: carrying out dischargedisassembly, sorting and grinding on the waste lithium batteries to obtain a positive electrode mixed material, preparing a slurry from the positive electrode mixed material and water, feeding the slurry, sulfur dioxide and air mixed gas into a reactor, and adjusting the molar ratio of Li to Co to Ni to Mn in the obtained leachate by adding a proper amount of metal ion salt; and adding a mixed solution of citric acid and polyethylene glycol, adjusting the pH value of the solution, controlling the temperature of the solution to be 70-85 DEG C, continuously stirring to obtain gel, drying the gel, calcining, and uniformly grinding to obtain the ternary lithium battery positive electrode material. According to the method, the four metals of lithium, cobalt, nickel and manganesein the waste lithium batt