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Leaching Mechanisms of Industrial Powders of Spent Nickel Metal Hydride Batteries in a Pilot‐Scale Reactor
Author(s) -
Zielinski Margot,
Cassayre Laurent,
Destrac Philippe,
Coppey Nicolas,
Garin Gilles,
Biscans Béatrice
Publication year - 2020
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201902640
Subject(s) - nickel , leaching (pedology) , hydride , dissolution , inductively coupled plasma , coprecipitation , chemistry , electron microprobe , metal , inorganic chemistry , materials science , metallurgy , nuclear chemistry , plasma , environmental science , physics , quantum mechanics , soil science , soil water
In view of a sustainable recycling process, the leaching mechanisms of nickel and rare‐earth elements (REEs) contained within industrial samples of spent nickel metal hydride battery powders were investigated in HCl and H 2 SO 4 , under mild temperature (25–60 °C) and pH (3–5.5). First, in‐depth characterization of the heterogeneous battery powder was carried out with powder XRD, SEM, electron probe microanalyzer wavelength‐dispersive spectroscopy (EPMA‐WDS) quantitative analyses of individual particles, and inductively coupled plasma optical emission spectrometry (ICP‐OES) elemental analysis. An unusual result is the identification of particles that exhibit a core–shell structure, which is related to anode active mass aging mechanisms. Then, a leaching study in a 10 L pilot‐scale reactor demonstrated the selective dissolution of REEs, with respect to nickel, at pH 3, which is attributed to 1) the kinetic inhibition of nickel metal dissolution, and 2) the specific core–shell structure of aged mischmetal particles. Furthermore, the use of H 2 SO 4 led to coprecipitation of lanthanide–alkali double sulfates and nickel salts.