Abstract
In the present study, the recovery of valuable metals from a Panasonic Prismatic Module 6.5 Ah NiMH 7.2 V plastic casing hybrid electric vehicle (HEV) battery has been investigated, processing the anode and cathode electrodes separately. The study focuses on the recovery of the most valuable compounds, i.e., nickel, cobalt and rare earth elements (REE). Most of the REE (La, Ce, Nd, Pr and Y) were found in the anode active material (33% by mass), whereas only a small amount of Y was found in the cathode material. The electrodes were leached in sulfuric acid and in hydrochloric acid, respectively, under different conditions. The results indicated that the dissolution kinetics of nickel could be slow as a result of slow dissolution kinetics of nickel oxide. At leaching in sulfuric acid, light rare earths were found to reprecipitate increasingly with increasing temperature and sulfuric acid concentration. Following the leaching, the separation of REE from the sulfuric acid leach liquor by precipitation as NaREE (SO4)2·H2O and from the hydrochloric acid leach solution as REE2(C2O4)3·xH2O were investigated. By adding sodium ions, the REE could be precipitated as NaREE (SO4)2·H2O with little loss of Co and Ni. By using a stoichiometric oxalic acid excess of 300%, the REE could be precipitated as oxalates while avoiding nickel and cobalt co-precipitation. By using nanofiltration it was possible to recover hydrochloric acid after leaching the anode material.
Highlights
It is well known that the hybrid electric vehicle (HEV) is becoming more common due to economic and environmental reasons
Nanofiltration can be applied to recycle used waste pickling acid [35], to separate rare earth elements (REE) from acid mine drainage and to deal with environmentally problematic wastes [36], to recover nickel [37] and to separate Nd from waste water [38]
The REE was separated from the hydrochloric acid anode leach liquors by precipitation as oxalates by the addition of oxalic acid
Summary
It is well known that the hybrid electric vehicle (HEV) is becoming more common due to economic and environmental reasons. The present project aims at developing an environmentally and economically sustainable hydrometallurgical process for recovery of the valuable elements from spent NiMH HEV batteries. The leaching outcomes under similar conditions have been reported [12,17,23,31], but the fate of the elements as a function of time is seldom reported for leaching of NiMH HEV batteries nor for the leaching of anode and cathode materials separately. The separation of REE from the leach liquors by precipitation and an integrated recovery of acid by nanofiltration have been investigated and assessed. Nanofiltration can be applied to recycle used waste pickling acid [35], to separate REE from acid mine drainage and to deal with environmentally problematic wastes [36], to recover nickel [37] and to separate Nd from waste water [38]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
