Recovery of cobalt, lithium, and manganese from the cathode active materials of spent lithium-ion batteries in a bio-electro-hydrometallurgical process

This work focuses on constructing a bio-electro-hydrometallurgical platform to efficiently recover cobalt (Co), lithium (Li), and manganese (Mn) from the cathode active materials (CAMs) of spent lithium batteries. A bioleaching process and selective adsorption by PC-88A/TOA-modified granular activated carbon were both incorporated into an electrokinetics approach to achieve excellent recycling performance. The technical feasibility was comprehensively investigated in terms of four aspects, including the domestication of microorganisms, the evaluation of the bioleaching process, the equilibrium adsorption of the adsorbent, and the electrokinetic recovery. Potential sulfur-oxidizing bacteria were screened and domesticated to a high concentration of pyrite pulp. The voltage gradient and the remediation time both had obvious influences on the recovery of the target elements in the electrokinetic process. Maximum recoveries of 91.45%, 93.64% and 87.92% for Co, Li, and Mn, respectively, were achieved from the CAMs of spent lithium-ion batteries via the electrokinetics process. The indirect oxidation of pyrite provided the necessary reductants for the platform. The transformation of sulfur (S) to H2SO4 as a result of bio-oxidation by bacteria strains supplied additional H+ ions to facilitate the reduction reaction, and acid dissolution mitigated the drawbacks caused by the uneven distribution of pH in the electrokinetics process.