A method for selectively extracting lithium from waste lithium iron phosphate materials

Abstract

The invention discloses a method for selectively extracting lithium from a waste lithium iron phosphate material, which comprises the following steps: immersing the waste lithium iron phosphate material in a sodium hydroxide solution, carrying out alkali leaching to remove aluminum, filtering, and removing aluminum from the filtered The material is dried to obtain lithium iron phosphate powder, and the filtered sodium aluminate filtrate is recovered; the lithium iron phosphate powder is put into a heating furnace, and the selective lithium extraction gas is introduced, and then roasted to obtain iron phosphate and lithium The compound of iron phosphate and lithium is added to the ball mill, wet ball milled, and filtered to obtain iron phosphate solid and lithium-containing solution respectively; the pH value of the lithium-containing solution is adjusted to 9.0‑11.0, and impurities are removed to obtain pure lithium solution; adding sodium carbonate solution to pure lithium solution for reaction, filtering, washing and drying the filtered solid to obtain lithium carbonate. The lithium in the waste lithium iron phosphate material is recovered by the method of the invention, and the recovery rate of the lithium is as high as 95 percent or more.

Description

technical field

[0001] The invention belongs to the technical field of comprehensive utilization of lithium ion battery electrode materials, and in particular relates to a method for selectively extracting lithium from waste lithium iron phosphate materials. Background technique

[0002] Lithium iron phosphate is currently the most widely used lithium-ion battery material, and is regarded by many industry insiders as the future development direction of lithium batteries. Since the 21st century, with the blowout development of the lithium battery new energy market, the problem of disposing of waste lithium iron phosphate batteries has become increasingly prominent.

[0003] Currently the most reported LiFePO 4 The waste treatment process is mainly borrowed from waste recycling processes such as lithium cobalt oxide and lithium nickel cobalt manganese oxide. Invention patent CN104953200A (method for recycling battery-grade iron phosphate in lithium iron phosphate batteries a...