Development of a Novel Solvent Extraction Process to Recover Cobalt, Nickel, Manganese, and Lithium from Cathodic Materials of Spent Lithium-Ion Batteries
Résumé
Lithium-ion batteries (LIBs) are widely used in industry today and their recycling turns out to be very important. This paper is focused on the selective recovery of cobalt(II), nickel(II), and manganese(II) contained in a leach solution obtained by digesting a cathodic material from spent LIB (NMC111, LiNi1/3Mn1/3Co1/3O2) with hydrochloric acid. After leaching the cathodic material, cobalt(II) was selectively extracted toward manganese(II) by liquid–liquid extraction with 0.4 mol L–1 Alamine 336 (tri-octyl/decyl amine) diluted in kerosene modified using 10% (vol) 1-dodecanol at an optimized phase volume ratio between the organic phase and the aqueous phase of O/A = 1/2. Afterward, manganese(II) was extracted from the cobalt-depleted aqueous phase using 0.7 mol L–1 Alamine 336 diluted in kerosene modified with 10% (vol) 1-dodecanol at O/A = 2. The resulting nickel(II)-lithium(I) acidic solution was neutralized at pH 8 with sodium hydroxide in order to precipitate almost all the nickel as nickel(II) hydroxide. The process can recover more than 99.9% cobalt(II) and produce an aqueous phase for further precipitation step containing 94.6% cobalt(II) and 5.4% manganese(II). Manganese(II) was recovered from the cobalt-depleted stream to produce manganese(II) solution, the purity of which was greater than 99.9%. Furthermore, this process allowed extracting more than 97.0% nickel(II) from the leach solution, which was precipitated as nickel(II) hydroxide. This precipitate contained 55.6% nickel(II), 7.85% chloride, 2.42% sodium(I), and 0.02% lithium(I). The effluent containing 0.649 g L–1 lithium(I) and 79.0 g L–1 sodium(I) could be processed by appropriate solvent extraction with Cyanex 936, that is, a phosphorus-based extractant specifically formulated for lithium–sodium separation from chloride media such as brines, or by implementing a precipitation stage to selectively recover lithium toward sodium.