Method for preferentially extracting lithium and manganese from waste lithium battery positive electrode material

The invention discloses a method for preferentially extracting lithium and manganese from a positive electrode material of a waste lithium battery, which comprises the following steps of: firstly, performing sulfating roasting to completely convert lithium and manganese into lithium sulfate and manganese sulfate; lithium and manganese are leached into the solution from the roasted material in a water leaching mode, and at the moment, a small amount of nickel sulfate and cobalt sulfate exist in the solution. Adding a certain amount of sodium sulfate into the solution to remove nickel and cobalt ions in the solution; after calcium hydroxide or calcium oxide is adopted to precipitate manganese ions in the solution, sodium carbonate is added into the solution to synthesize lithium carbonate, reduction acid leaching is adopted for separation of manganese hydroxide and calcium sulfate, and manganese sulfate is concentrated and crystallized to generate manganese sulfate. The method is safe and controllable in green