Method for recycling lithium from waste batteries

The invention discloses a method for recycling lithium from waste batteries, which comprises the following steps: S1, immersing electrode material slurry into an alkaline aldehyde solution, reacting for a period of time, and then carrying out solid-liquid separation and washing to obtain valuable metal hydroxide precipitate and a lithium-containing solution; s2, sodium carbonate is added into the lithium-containing solution, and industrial-grade lithium carbonate is obtained through solid-liquid separation; and S3, dissolving the valuable metal hydroxide precipitate by using a sulfuric acid solution, and carrying out solid-liquid separation to obtain a solution containing nickel, cobalt and manganese ions. Compared with an acid leaching mode in the prior art, the alkaline leaching mode is adopted, the leaching effect is good, various valuable by-products can be generated, particularly, metal copper cannot be dissolved under the moderate alkaline condition, copper simple substances can be recycled, and the val