Method for selectively recovering valuable metals from waste lithium ion batteries

The invention discloses a method for selectively recovering valuable metals from a waste lithium ion battery. The method comprises the following steps: (1) discharging the waste nickel cobalt lithium manganate ion battery, and disassembling a positive plate; (2) putting the positive plate into a selective extracting agent and adjusting the solid-to-liquid ratio to prepare a hydrothermal leaching reaction system; introducing oxygen into the reaction container, then sealing the reaction container, and carrying out hydrothermal leaching; (3) opening the reaction container after the reaction container is naturally cooled, carrying out solid-liquid separation on the materials in the reaction container to obtain a lithium-rich solution and lithium-removed slag, and drying the lithium-removed slag; (4) carrying out secondary leaching on the dried lithium-removed slag by using acid and a reducing agent; and after the secondary leaching is finished, carrying out solid-liquid separation to obtain a nickel-cobalt-mangan