PROCESS FOR RECOVERY OF METALS FROM USED NICKEL/METAL HYDRIDE STORAGE BATTERIES

摘要

An H2SO4/H2O2 mixture that dissolves in particular the AB5 type hydrogenstorage alloys that form the main component of negative electrodes withoutleaving any residues is suitable to disintegrate the fine fraction containingthe positive and negative electrode active material mechanically separatedfrom scrap accumulators. Excess H2O2 is then destroyed and Fe3+ is reducedinto Fe2+ by flowing the strongly acid disintegration solution over themetallic coarse fraction, so that the rare earths from the storage alloys maybe precipitated as double sulphates without Fe impurities. Ni and Co may berecovered together by solvent extraction and simultaneous electrolysis. Theseparated product may be used as pre-alloy for producing new hydrogen storagealloys. The process may be carried out without problems even when because ofsorting errors the scrap accumulators contain a small proportion of Ni/Cdbatteries.