Abstract
The recovery of platinum group metals (PGMs) from waste materials involves dissolving the waste in an aqueous solution. However, since PGMs are precious metals, their dissolution requires strong oxidizing agents such as chlorine gas and aqua regia. In this study, we aimed to recover PGMs via the calcination of spent automotive catalysts (autocatalysts) with Li salts based on the concept of “spent autocatalyst + waste lithium-ion batteries” and leaching with only HCl. The results suggest that, when Li2CO3 was used, the Pt content was fully leached, while 94.9% and 97.5% of Rh and Pd, respectively, were leached using HCl addition. Even when LiF, which is a decomposition product of the electrolytic solution (LiPF6), was used as the Li salt model, the PGM leaching rate did not significantly change. In addition, we studied the immobilization of fluorine on cordierite (2MgO·2Al2O3·5SiO2), which is a matrix component of autocatalysts. Through the calcination of LiF in the presence of cordierite, we found that cordierite thermally decomposed, and fluorine was immobilized as MgF2.
Highlights
LargoPlatinum group metals (PGMs), which include Pt, Pd, Rh, Ir, Ru, and Os, are used in various fields, including catalysis
The term EV refers to both battery electric vehicles (BEVs) and plugin hybrid electric vehicles (PHEVs)
platinum group metals (PGMs) showed maximum leaching rates from the samples calcined at 800◦ °C; the entire amount of Pt, 85.0% of Rh, and 86.5% of Pd were leached calcined at 800 C; the entire amount of Pt, 85.0% of Rh, and 86.5% of Pd were leached under this condition
Summary
Platinum group metals (PGMs), which include Pt, Pd, Rh, Ir, Ru, and Os, are used in various fields, including catalysis. On an industrial scale, acids containing oxidizing agents such as chlorine gas and aqua regia (a mixture of HCl and nitric acid) are employed [6,7]. To avoid the use and generation of toxic gases, we proposed a novel dissolution process for PGMs based on composite oxides [8,9,10,11,12,13]. In order to recover metals from LIBs, we applied a carbon reduction method, which utilizes carbon powder as a reducing agent. HF emission from PVDF was drastically suppressed by the addition of calcium salts [27,28] It is, necessary to consider removing F from the recovered materials or to apply processes to these materials that tolerate the presence of F. We examine the immobilization of F on cordierite (2MgO·2Al2 O3 ·5SiO2 ), which is a matrix component of autocatalysts, with the aim of realizing cleaner production
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
