An integrated process for the separation and recovery of valuable metals from the spent LiNi0.5Co0.2Mn0.3O2 cathode materials

Abstract

The recycling of the spent lithium-ion batteries has aroused widespread concern due to the internal harmful substances and valuable metals. In this work, a novel integrated recovery process for the spent LiNi0.5Co0.2Mn0.3O2 cathode materials was proposed, which realized the complete separation of metals via leaching – cascade extraction – precipitation methods. Here, 2 mol/L (M) sulfuric acid (H2SO4) and 3 vol% (volume ratio) hydrogen peroxide (H2O2) were employed as leaching agents, resulting in the leaching rate of all metals are above 99%. Subsequently, the cascade extraction was adopted to separate lithium (Li) – nickel (Ni) – cobalt (Co) – manganese (Mn) by P227 (di-(2-ethylhexyl) phosphinic acid) and P204 (di-(2-ethylhexyl) phosphoric acid) extractants, respectively. Meanwhile, their high purity solid products such as MnO2, Li2CO3, NiO and Co3O4 were also obtained depending on the precipitation procedure. The yield and purity of these metals in the final products are 96.15%/100% for Li, 91.54%/98% for Ni, 91.15%/93% for Co, and 91.56%/100% for Mn, respectively. More importantly, this simple recovery process opens an avenue in the industrial applications for separating critical metals from the spent lithium-ion batteries.