Total Recovery of Gold Contained in Computer Printed Circuit Boards. Leaching Kinetics of Cu, Zn and Ni

Authors

  • María Isabel Reyes UAEH, Ciudad Universitaria
  • Isauro Rivera UAEH, Ciudad Universitaria
  • Francisco Patiño UAEH, Ciudad Universitaria
  • Mizraim U. Flores UAEH, Ciudad Universitaria
  • Martín Reyes UAEH, Ciudad Universitaria

DOI:

https://doi.org/10.29356/jmcs.v56i2.312

Keywords:

Gold, printed circuit boards, kinetics, leaching, recovery

Abstract

In this study a thorough characterization of certain printed circuit boards has been carried out; it was found that they are made up of a polymer layer, a metal layer of Cu, Zn and Ni, and a gold substrate. A kinetic study of the acid dynamic leaching of copper, zinc and nickel has been carried out, finding out that these elements’ dissolution allows the gold substrate to be physically separated; then, the gold particles are separated from the polymer by filtration. The reaction orders were calculated vs. H2SO4 concentration, and the activation energy was calculated as well; reaction orders of n = 0.265, n = 0.247 and n = 0.245 were found for Cu, Zn and Ni respectively, while Ea = 86.3, Ea = 95.3 and Ea = 11.2 kJ/mol were found for Cu, Zn and Ni respectively. When the attack time is over, a shiny, solid product has been obtained; it was characterized by SEM-EDS and AAS, confirming that it is metallic gold, with a purity of 100 and 99.9% according to the respective technique.

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Author Biographies

María Isabel Reyes, UAEH, Ciudad Universitaria

Área Académica de Ciencias de la Tierra y Materiales

Isauro Rivera, UAEH, Ciudad Universitaria

Área Académica de Ciencias de la Tierra y Materiales

Francisco Patiño, UAEH, Ciudad Universitaria

Área Académica de Ciencias de la Tierra y Materiales

Mizraim U. Flores, UAEH, Ciudad Universitaria

Área Académica de Ciencias de la Tierra y Materiales

Martín Reyes, UAEH, Ciudad Universitaria

Área Académica de Ciencias de la Tierra y Materiales

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Published

2017-10-12

Issue

Section

Regular Articles

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