Green separation of lanthanum, cerium and nickel from waste nickel metal hydride battery

authors	Vargas, SJR; Schaeffer, N; Souza, JC; da Silva, LHM; Hespanhol, MC
nationality	International
journal	WASTE MANAGEMENT
author keywords	Critical metal; Circular economy; Waste battery; Aqueous biphasic system; Rare earth elements
abstract	In a circular economy context, there is a growing need for more sustainable waste management options to recover elements from end-of-life materials. These secondary ores represent a source of critical elements that are often present in higher concentration compared to their primary ore. In this work, the recovery of lanthanum (La) from waste nickel metal hydride battery (NiMH) leachate is investigated using an aqueous biphasic system (ABS) process based on a pluronic triblock copolymer (L35). An initial screening is performed to determine the influence of the ABS phase forming salt anion and alizarin red extractant on the La extraction efficiency and selectivity. From these results, a three-step ABS process is developed, varying only the nature of the salt and requiring no additional extractant. In a first step, the ABS composed of L35 + thiocyanate ammoniun + H2O efficiently extracts iron, manganese, and cobalt leaving La, cerium, and Ni in solution. Nickel is subsequently recovered by precipitation using dimethylglyoxime. Finally, La is separated from cerium using the L35 + ammonium nitrate + H2O ABS, recovering 62 g of La with 94% purity per kilogram of black mass of NiMH battery. This work highlights the applicability of ABS for the treatment of raw and complex matrices, potentially allowing for a greener hydrometallurgical treatment of wastes. (C) 2021 Elsevier Ltd. All rights reserved.
publisher	PERGAMON-ELSEVIER SCIENCE LTD
issn	0956-053X
isbn	1879-2456
year published	2021
volume	125
beginning page	154
ending page	162
digital object identifier (doi)	10.1016/j.wasman.2021.02.038
web of science category	9
subject category	Engineering, Environmental; Environmental Sciences
unique article identifier	WOS:000632596000016