Metal recovery from NiMH batteries

NiMH sealed cells (portable cells) are today widely used in all consumer applications replacing primary alkaline batteries. wireless mobile communication, portable computers and camcorders, are the largest application segments. The Italian market of NiMH cells is steadily growing, following the impressive penetration rate of the cellular phones. The organization of a national collecting system and correct recycling process are the key factors to prevent environmental impact associated to these wastes, while the metal values recovery can improve the feasibility of the recycling process The University of Rome, Texeco Engineering S.r.1., and MO.SMO.DE. S.a.s, have developed a combination of mechanical and hydrometallurgical processing to recover Nickel, and Cobalt salable products and rare earths intermediate products. A new plant located in South Italy, designed after this technology, is able to recycle waste NiMH batteries collected in the Italian territory, together with other industrial and portable batteries based on different chemistries. The process is able to treat both individual cells and plastic power packs and includes as basic steps an original crushing and elutriation treatment to separate plastic, metallics, and active mass components that are subsequently treated by a hydrometallurgical process to recover Ni, Co, and RE. The hydrometallurgical main steps are: acidic leaching, R.E separation, multistage precipitation of Ni, Co and Fe and final solvent extraction on dissolved Ni and Co salts. For each operation the operative condition have been determined.