Thiourea Leaching: An Update on a Sustainable Approach for Gold Recovery from E-waste

Daniel A. Ray, Mahsa Baniasadi, John E. Graves, Alan Greenwood, Sebastien Farnaud

Research output: Contribution to journalReview articlepeer-review

15 Citations (Scopus)
196 Downloads (Pure)

Abstract

Abstract: Electronic waste is a dominant global issue with over 50 million tons generated annually. Still, as an amalgamation of precious and rare raw materials, electronic waste is a considerable economic resource with the most valuable components located on the printed circuit boards. Gold is widely used in electronics in numerous applications, although principally for contact points and external connectors. The recovery of gold, due to its high value, is one of the main motivations for recycling e-waste. Although pyrometallurgy and hydrometallurgy processing are still the preferred modes of recovery for gold, the use of high-energy consuming pyro-methods, and the use of gold cyanidation that uses harmful lixiviants are increasingly discouraged. Thiourea has received attention as an alternative lixiviant for gold leaching due to its fast reaction kinetics and less harmful nature. This review aims to provide an up-to-date evaluation of thiourea-gold leaching studies from electronic waste, with emphasis on the recent progression from the classic chemical method to a more sustainable hybrid bioleaching-based system, while its challenges are highlighted. The complementary methods applied for gold retrieval from the pregnant solution are also described with a focus on sustainable methods that have the potential to provide a closed-loop system, the key objective for material recovery in a circular economy. Graphical Abstract: [Figure not available: see fulltext.]

Original languageEnglish
Pages (from-to)597-612
Number of pages16
JournalJournal of Sustainable Metallurgy
Volume8
Issue number2
Early online date18 Mar 2022
DOIs
Publication statusE-pub ahead of print - 18 Mar 2022

Bibliographical note

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

Keywords

  • Biohydrometallurgy
  • E-waste
  • Gold
  • Recovery
  • Recycling
  • Thiourea

ASJC Scopus subject areas

  • Environmental Science (miscellaneous)
  • Mechanics of Materials
  • Metals and Alloys

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