Effective Alloying Treatment for Platinum Using Iron Chloride Vapor

Abstract

An effective alloying treatment for Pt using FeCl x (x = 2, 3) vapor was demonstrated towards developing a novel recovery process for platinum group metals (PGMs) in catalyst scrap. Suitable reaction conditions were discussed from the perspective of thermodynamics, and its validity was con rmed experimentally. When pure Pt samples were reacted with FeCl 2 vapor at 1200 K under the coexistence of metallic Fe, an Fe-Pt alloy showing ferromagnetism was easily formed, even though the samples were not in physical contact with the metallic Fe. On the basis of thermodynamic considerations, alloying of Pt mainly proceeds via the disproportionation of FeCl 2 vapor, with the gaseous phase containing FeCl x acting as the medium to transport Fe from the metallic Fe to the Pt samples. When the alloyed sample was kept under FeCl 3 vapor at 1200 K, Fe was removed and ferromagnetism was lost. Therefore, it is concluded that FeCl 2 vapor treatment under the coexistence of Fe is a feasible and useful technique for alloying Pt and forming a ferromagnetic Fe-Pt alloy. The results obtained in this study indicate that treatment with FeCl 2 vapor followed by magnetic separation has potential as an effective technique for concentrating PGMs directly from catalyst scrap.

Trash or treasure? Sustainable noble metal recovery

“…Their findings revealed that, under the experimental conditions of 550 °C and 2 : 3 for CO : Cl 2 composition, the recovery rates for Pt and Rh were 95.9% and 92.9%, respectively. Taninouchi et al 25 employed the generation of Fe to capture Pt, forming alloys through the FeCl 2 gas disproportionation reaction at elevated temperatures. The newly formed Fe-Pt solid solution could be concentrated through magnetic separation.…”

Обзор: Извлечение Металлов Платиновой Группы Из Каталитических Конвертеров

“…В настоящее время разработаны более экономичные и экологичные методы переработки металлов платиновой группы [102,103,[142][143][144].…”

“…Концентрированные металлы платиновой группы представляют собой большую ценность и имеют намного меньший объём, чем необработанные отходы. Данные процессы могут быть проведены на небольших установках с маленьким затрачиванием энергии и без выделения вредных токсичных веществ [102,103,142,144,145].…”

Liquid‐ and Solid‐based Separations Employing Ionic Liquids for the Recovery of Platinum Group Metals Typically Encountered in Catalytic Converters: A Review

“…Alternatively, treatment of the spent catalyst material with FeCl 2 vapor can be used to convert Pt to the ferromagnetic Pt−Fe alloy. Subsequent exposure of the alloy to FeCl 3 vapor leads to dealloying and removal of Fe [87] . This approach is also applicable for the recovery of Pd and Rh [88] .…”

“…Subsequent exposure of the alloy to FeCl 3 vapor leads to dealloying and removal of Fe. [87] This approach is also applicable for the recovery of Pd and Rh. [88] Fast separation, low cost, and limited environmental impact are the major advantages of the magnetic‐based separation.…”