PROCESS FOR RECOVERY OF METALS FROM USED NICKEL-METAL HYDRIDE ACCUMULATORS

摘要

When recycling used nickel-metal hydride accumulators, scrap batteries are dissolved in sulphuric acid after the coarse components have been mechanically separated in a magnetic wind sifter. Rare earths (from the hydrogen storage alloys in the negative electrodes), iron and aluminium are precipitated, then the disintegration solution is solvent-extracted in such conditions (pH value, choice of solvent, volume ratio between the phases) that the quantity and atomic ratio of nickel and cobalt is the same in the aqueous phase as in the scrap. They can thus be recovered together by simultaneous electrolysis. The separated product forms a pre-alloy that may be used together with the precipitated rare earths converted by an electrometallurgical process into mischmetal to produce new hydrogen storage alloys.