@article{ac4d5c9251b841c7b5da60df98491924,
title = "Lanthanide-alkali double sulfate precipitation from strong sulfuric acid NiMH battery waste leachate",
abstract = "In NiMH battery leaching, rare earth element (REE) precipitation from sulfate media is often reported as being a result of increasing pH of the pregnant leach solution (PLS). Here we demonstrate that this precipitation is a phenomenon that depends on both Na+ and SO4 2− concentrations and not solely on pH. A two-stage leaching for industrially crushed NiMH waste is performed: The first stage consists of H2SO4 leaching (2 M H2SO4, L/S = 10.4, V = 104 ml, T = 30 °C) and the second stage of H2O leaching (V = 100 ml, T = 25 °C). Moreover, precipitation experiments are separately performed as a function of added Na2SO4 and H2SO4. During the precipitation, higher than stoichiometric quantities of Na to REE are utilized and this increase in both precipitation reagent concentrations results in an improved double sulfate precipitation efficiency. The best REE precipitation efficiencies (98–99%) – achieved by increasing concentrations of H2SO4 and Na2SO4 by 1.59 M and 0.35 M, respectively – results in a 21.8 times Na (as Na2SO4) and 58.3 times SO4 change in stoichiometric ratio to REE. Results strongly indicate a straightforward approach for REE recovery from NiMH battery waste without the need to increase the pH of PLS.",
keywords = "Double sulfate, Hydrometallurgy, Nickel metal hydride battery, Rare earths, Recycling, Alkalies, Sulfuric Acids/chemistry, Lanthanoid Series Elements/chemistry, Nickel, Sulfates, Electronic Waste",
author = "Antti Porvali and Wilson, {Benjamin P.} and Mari Lundstr{\"o}m",
note = "Funding Information: The authors acknowledge METYK project for providing the context where the work was performed. METYK project was financially supported by TEKES, EU, Vipuvoimaa EU:lta 2014-2020, Norilsk Nickel, CrisolteQ, Akkuser, Kuusakoski, Jyv?skyl?n Energia, Luvata, Boliden Harjavalta and municipalities of Pori and Harjavalta. This work has also been supported by the Strategic Research Council at the Academy of Finland, project CloseLoop (grant number 303454), NoWASTE (grant number 297962), MineWEEE (7100/31/2016) and made use of the RawMatTERS Finland Infrastructure (RAMI) based at Aalto University. The authors would like to thank Petteri Halli for operating the SEM-EDS. Funding Information: The authors acknowledge METYK project for providing the context where the work was performed. METYK project was financially supported by TEKES, EU, Vipuvoimaa EU:lta 2014-2020, Norilsk Nickel, CrisolteQ, Akkuser, Kuusakoski, Jyv{\"a}skyl{\"a}n Energia, Luvata, Boliden Harjavalta and municipalities of Pori and Harjavalta. This work has also been supported by the Strategic Research Council at the Academy of Finland , project CloseLoop (grant number 303454 ), NoWASTE (grant number 297962), MineWEEE ( 7100/31/2016 ) and made use of the RawMatTERS Finland Infrastructure (RAMI) based at Aalto University. The authors would like to thank Petteri Halli for operating the SEM-EDS. Publisher Copyright: {\textcopyright} 2017 The Authors Copyright: Copyright 2018 Elsevier B.V., All rights reserved.",
year = "2018",
month = jan,
doi = "10.1016/j.wasman.2017.10.031",
language = "English",
volume = "71",
pages = "381--389",
journal = "Waste Management",
issn = "0956-053X",
publisher = "Elsevier",
}