廃リチウムイオン二次電池塩酸浸出液からの金属の溶媒抽出分離プロセス

Abstract

The lithium ion secondary batteries (LIBs) contain valuable metallic components and although spent LIBs are not generally classified as dangerous waste, recovery of these metals is necessary from an economic point of view. In this work, separation of main metals such as aluminum, copper, cobalt and lithium contained in spent LIBs has been investigated using a hydrometallurgical treatment based on solvent extraction. The results obtained this study are summarized as follows: Aluminum could not be selectively separated from copper and cobalt by the precipitation method as hydroxide because the precipitation curves of aluminum and copper were close and cobalt was precipitated due to the coprecipitation with aluminum hydroxide or copper hydroxide. Meanwhile, aluminum could be selectively separated from cobalt and lithium with solvent extraction using PC-88A at pH 2.0–2.5 after the selective extraction of copper with Acorga M5640 at pH 1.0–2.0 while leaving cobalt and lithium in the raffinate. Acorga M5640 was efficient and selective for the extraction of cobalt at pH of approximately 6.0 while leaving lithium in the raffinate. However, the stripping efficiency of Co from organic phase (Acorga M5640) was very low. Therefore, the extractant combination, PC-88A/TOA, was favorable to the separation of Co and Li at pH of approximately 5.0 compared with Acorga M5640. A separation process of aluminum, copper, cobalt and lithium from the spent LIBs using hydrometallurgical treatment based on solvent extraction was proposed.