In recent years, the rapid development of battery industry has increased a lot in demand for lithium ion batteries. Due to the light weight, high energy capacity and good performance of LiNi_0.8Co_0.15Al_0.05O₂ (NCA) and LiNi_1-x-yMn_xCo_yO₂ (NMC) cathode materials-based lithium ion batteries, the usage of these cathode materials has rapidly increased. The recycle of these cathode materials has attracted a lot of attentions because of the large quantity and environmental conservation. Oxalic acid is a good leaching agent for these two cathode materials, but the subsequent process needs further study. In this research, the oxalates obtained from oxalic acid leaching of NCA and NMC cathode materials will be investigated to recycle each metal element.

The acid baking and the Co oxidation...[ Read more ]

In recent years, the rapid development of battery industry has increased a lot in demand for lithium ion batteries. Due to the light weight, high energy capacity and good performance of LiNi_0.8Co_0.15Al_0.05O₂ (NCA) and LiNi_1-x-yMn_xCo_yO₂ (NMC) cathode materials-based lithium ion batteries, the usage of these cathode materials has rapidly increased. The recycle of these cathode materials has attracted a lot of attentions because of the large quantity and environmental conservation. Oxalic acid is a good leaching agent for these two cathode materials, but the subsequent process needs further study. In this research, the oxalates obtained from oxalic acid leaching of NCA and NMC cathode materials will be investigated to recycle each metal element.

The acid baking and the Co oxidation processes were selected and optimized for the treatment of oxalates obtained by oxalic acid leaching from NCA cathode material. In the acid baking process, the effects of baking time, sulfuric acid dosage and baking temperature on the recovery of Ni/Co were investigated. In the Co oxidation process, the effects of reaction time, S/L ratio, molar ratios of sodium persulfate to Co, reaction temperature and pH on Co oxidation were studied. The total Co and Ni recovery reached 97%. The dissolution of NMC oxalates (together with Mn oxidation) and the solvent extraction processes were selected and optimized for the treatment of oxalates obtained by oxalic acid leaching from NMC cathode material. In the dissolution of NMC oxalates process, the effects of reaction time, S/L ratio, molar ratio of sodium persulfate to oxalates, reaction temperature and pH were investigated. In the solvent extraction process, the effects of extractant concentration, saponification ratio and initial pH on Co and Ni extraction were studied. The total Mn, Co and Ni recovery were 95%, 87% and 94%, respectively.