Palladium Pressure Leaching Kinetics in Chloride Medium, from Printed Circuit Boards, in a Pressure Reactor

Guadalupe Martínez-Ballesteros, Jesús Leobardo Valenzuela-García, Patricia Guerrero-Germán, María Mercedes Salazar-Campoy, Agustín Gómez-Alvarez

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

The recovery of palladium (Pd) from recycling printed circuit boards (PCBs) has attracted attention in recent years, because the metal is found in low concentrations in the earth's crust and the demand for it has increased due to its chemical and physical properties, therefor, in addition to being used in jewelry, it is used in catalytic converters, dentistry, medicine, watchmaking, aircraft spark plugs, and electronic products. Currently, the extraction of Pd from waste PCBs through an efficient and ecological process remains a challenge, since a process that meets these two characteristics has not been found. In the present study, palladium leaching was carried out in a PARR titanium reactor with an acid leaching agent under pressure from printed circuit boards, using [NaCl]=0.017 M, [NaClO]= 0.067 M and varying the concentration of hydrochloric acid, pressure, and temperature,. The best results were obtained using at 0.34 MPa, 70°C and [HCl] acid concentration of 4 M, This was based on the thermodynamic analysis of the Pd-Cl-H2O system, using the Eh-pH diagram. In addition, the study of the extraction kinetics was carried out to know the leaching reaction mechanism. The activation energy (Ea) was determined to be 0.03 kJ/mol. At less than 1 kJ/mol, the mechanism is expected to be diffusion through the product layer. Under these conditions, an extraction of 93% of Pd was achieved.

Original languageEnglish
Title of host publication9th International Symposium on Hydrometallurgy 2023
PublisherSociety for Mining, Metallurgy and Exploration
ISBN (Electronic)9780873355216
StatePublished - 2023
Event9th International Symposium on Hydrometallurgy 2023 - Phoenix, United States
Duration: 27 Aug 202330 Aug 2023

Publication series

Name9th International Symposium on Hydrometallurgy 2023

Conference

Conference9th International Symposium on Hydrometallurgy 2023
Country/TerritoryUnited States
CityPhoenix
Period27/08/2330/08/23

Bibliographical note

Publisher Copyright:
Copyright © 2023 Society for Mining, Metallurgy & Exploration. All Rights Reserved.

Keywords

  • kinetic model
  • Palladium
  • printed circuit boards
  • recycling

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