Rare earths recovery from NiMH spent batteries

Nickel-metal hydride batteries (NiMH) contain rare earths (RE) and a variety of valuable metals such as nickel and cobalt. Using a hydrometallurgical process developed for the recovery of metals from spent batteries, a selective separation of RE by precipitation of Sodium RE double sulfate can be performed. Leaching solution was obtained by using 2 M H2SO4 at 20 °C. The paper reports the experimental studies involving the precipitation process and the characterisation by X-ray diffraction of the resulting product (Sodium RE double sulfates). It has been shown that it is possible to recover about 80% of the RE contained in spent NiMH batteries.