Recovery of rare metal compounds from nickel-metal hydride battery waste and their application to CH4 dry reforming catalyst

The recovery of valuable components such as nickel from nickel-metal hydride (Ni-MH) battery waste by chemical processes and their applications to CH4 dry reforming catalysts were investigated. Three types of compound, identified by XRD analysis as NiO, CeO2 and LaCoO3 phases, were successfully separated from the waste by a series of chemical processes at room temperature using aqueous solutions of HCl, NaOH and NH3, and Ni component of ≈70% in Ni-MH battery waste was recovered. The separated NiO, CeO2 and LaCoO3 showed catalytic activities for CH4 dry reforming. In particular, the separated NiO easily reduced to Ni0 at an initial stage, and exhibited excellent catalytic activity in terms of CH4 conversion and stability. Furthermore, it was found that the resulting Ni from separated NiO exhibited an anomalous catalysis from the comparison with that from regent NiO.