Circulation of Sodium Sulfate Solution Produced During NiMH Battery Waste Processing

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2019-06-12
Major/Subject
Mcode
Degree programme
Language
en
Pages
Series
Mining, Metallurgy & Exploration
Abstract
Hydrometallurgical recovery of rare earth elements (REE) from NiMH battery waste can be performed using sulfuric acid leaching followed by selective precipitation as double salt (REENa(SO4)2·H2O) by adding Na2SO4 as a precipitating agent. The formed double salts can then be further converted with NaOH solution to form REE hydroxides. However, present literature has paid little attention to how to minimize the consumption of reagents in this recovery process. In the current study, a process model was built using HSC Sim software, and metamodeling of the simulated flowsheet was conducted with the design of experiments (DOE), after which the basic functionality of the flowsheet was verified by experimental work, starting from sulfuric acid leaching of spent batteries. As the process is based on chemical circulation internally in the process, the objective was to investigate the accumulation of the elements in solution, specifically Na+, K+, SO42− ions and impurities liberated in the NaOH conversion step. It was found out that metamodeling could be utilized in obtaining first estimate of the process behavior, prior to any experiments. Flowsheet functionality with circulated solution was confirmed, obtaining at best 96.9% La recovery.
Description
Keywords
Battery waste, Flowsheet metamodeling, Hydrometallurgy, Rare earths, Recycling, Response surface methodology
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Citation
Porvali , A , Agarwal , V & Lundström , M 2019 , ' Circulation of Sodium Sulfate Solution Produced During NiMH Battery Waste Processing ' , Mining, Metallurgy & Exploration . https://doi.org/10.1007/s42461-019-0086-2