Recycling of end-of-life LiNixCoyMnzO₂ batteries for rare metals recovery

An investigation of rare metals recovery from LiNixCoyMnzO2 cathode material of the end-of-life lithium-ion batteries is presented. To determinethe influence of reductant on the leach process, the cathode material (containing Li 7.6%, Co 20.4%, Mn 19.4%, and Ni 19.3%) was leachedin H2SO4 solutions either with or without H2O2. The optimal process parameters with respect to acid concentration, addition dosage of H2O2,temperature, and the leaching time were found to be 2.0 M H2SO4, 4 vol.% H2O2, 70°C, and 150 min, respectively. The yield of metal valuesin the leach liquor was > 99%. The leach liquor was subsequently treated by precipitation techniques to recover nickel as Ni(C4H7N2O2)2 andlithium as Li2CO3 with stoichiometric ratios of 2:1 and 1.2:1 of dimethylglyoxime:Ni and Na2CO3:Li, respectively. Cobalt was recovered by solventextraction following a 3-stage process using Na-Cyanex 272 at pHeq ~5.0 with an organic-to-aqueous phase ratio (O/A) of 2/3. The loaded organicphase was stripped with 2.0 M H2SO4 at an O/A ratio of 8/1 to yield a solution of 114 g/L CoSO4; finally recovered CoSO4.xH2O by crystallization. The process economics were analyzed and found to be viable with a margin of $476 per ton of the cathode material. KCI Citation Count: 0