Method for selectively extracting lithium from retired lithium battery

The invention discloses a method for selectively extracting lithium from a retired lithium battery, and relates to the technical field of retired lithium battery recovery. The method comprises the following steps: discharging the retired lithium battery, disassembling, drying in a negative pressure environment to obtain a positive plate, crushing, and screening to obtain a retired lithium batterypositive active substance; fully grinding the positive active material and an activating agent; putting a positive active substance-activating agent mixture into a tubular furnace for activation at the temperature of 200-450 DEG C for 10-120 minutes, and leaching the activated substance to extract lithium, thereby obtaining a Li-enriched solution; and adding carbonate and/or phosphate into the Li-enriched solution to obtain lithium carbonate and/or lithium phosphate. The method has the beneficial effects that the reactivity of a lithium element is improved by utilizing the activating agent, Liis efficiently and select