Method for extracting cobalt from waste ternary lithium ion battery

The invention relates to a recycling method of a lithium ion battery, in particular to a method for extracting cobalt from a waste ternary lithium ion battery, which comprises the following steps: preparing battery black powder into slurry, sequentially performing acid leaching, copper removal and iron removal to obtain an impurity extraction pre-solution, mixing the impurity extraction pre-solution with a first extraction agent and a first extraction agent solution of an ether solvent, and performing secondary extraction to obtain a secondary extraction solution; mixing the primary extraction raffinate with a second extraction agent solution containing a saponified second extraction agent, carrying out a second extraction step to obtain a crude cobalt solution, mixing the first extraction agent solution with the crude cobalt solution, and carrying out a third extraction step to obtain a refined cobalt solution, and evaporating the refined cobalt solution to obtain a cobalt salt crystal product. According to