Leaching of Pt, Pd and Rh from Automotive Catalyst Residue in Various Chloride Based Solutions

Abstract

Platinum-group metals (PGM) are important precious metals in many industrial fields. However, their natural resource deposits are strictly limited. Accordingly, their recycling process from wastes and/or secondary resources must be considered. In this study, the leaching of PGM from automotive catalyst residue was performed based on the formation of their chloro-complexes in various concentration of acidic solution. The recovery of platinum, palladium and rhodium from the samples after hydrogen reduction pretreatments was examined in the leaching process by using a mild solution mixture of NaClO-HCl and H 2 O 2 at 65 C for 3 h. Effect of other solution mixtures on the extraction of the precious metals was also compared with NaClO-HCl-H 2 O 2 , such as HCl-H 2 O 2 and NaClO-HCl. The optimum condition to dissolve platinum, palladium and rhodium was achieved by the mixture of 3 vol% NaClO, 5 kmolÁm À3 HCl and addition of 1 vol% H 2 O 2 . The recovery of platinum, palladium and rhodium after 3 h leaching reaches 88%, 99%, 77%, respectively.

Selective Extraction of Precious Metal from Automotive Catalyst Residue by Thiacalix[6]arene Derivatives

“…PGM solution was prepared from an automotive catalyst residue by treating with leaching solution, which contains HC1 (11.6 M) and H2O2 (1 vol.%) [1].…”

“…That's why a recycle of PGM from wastes and/or secondary resource such as spent automotive catalyst or residue is very important. For example,the recovery of PGM by the leaching from automotive catalyst residue has been reported [1]. So far, separation of precious metals is done by the solvent extraction because industrial process is very easy.…”

“…In this article, we would like to report the synthesis method of new TC6A derivatives, 5 with high selectivity from automotive catalyst residues, which is named as PGM solution [1]. …”

Potential of a Hydrometallurgical Recycling Process for Catalysts to Cover the Demand for Critical Metals, Like PGMs and Cerium

“…To obtain optimum efficiency rates, special conditions, like specific redox potential, low pH, specified solid to liquid ratio, stirring rate, and temperature have to be chosen. Many authors, such as Harjanto et al, 10 investigated the best leaching conditions in different media. During this step, soluble chlorocomplexes are formed, as this is shown in Eq.…”

Dissolution Rate of Noble Metals for Electrochemical Recycle in Polymer Electrolyte Fuel Cells

“…8 The other techniques used in the automotive catalysts recycling with HCl-H 2 O 2 mixed solution would be applicable to the PEFC systems. 10,11 The combustion of membrane electrode assemblies (MEAs) would be the candidate for the recycling method. However, incinerators would be damaged by the fluorine gas derived from the combustion of fluorinated membranes such as Nafion μ , Flemion μ , and Aciplex μ .…”