Leaching of Gold and Silver from Crushed Au-Ag Wastes

Jana Ficeriová*, a, Peter Baláza, Erika Dutková, Eberhard Gockb
a Institute of Geotechnics of the SAS, Watsonova 45, 043 53 Košice, Slovakia
2 Institute of Mineral and Waste Processing and Dumping Technology, Technical University Clausthal, Walther-Nernst Strasse 9, 38 678 Clausthal-Zellerfeld, Germany

© 2008 Ficeriová et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Institute of Geotechnics of the SAS, Watsonova 45, 043 53 Košice, Slovakia; Fax: + 421-55-7922604; E-mail:


Au-Ag noble metal wastes represent a wide range of waste types and forms with various ballast elements and components. The thiourea process of gold and silver extraction from ores, concentrates or secondary raw materials consists of gold and silver leaching into the thiourea solution and the consequent precipitation of these metals from the solution. Due to the non-toxic character of thiourea it is the perspective alternative to the up to now most frequently used cyanide method. The thiourea leaching of gold and silver from electronic waste, goldsmith’s waste and ceramic waste using crushing as the pretreatment step was investigated. For electronic waste, it was possible to achieve 97 % gold and 94 % silver recovery within 120 minutes of thiourea leaching. Up to 98 % of gold and 96 % of silver were recovered from goldsmith’s waste after 60 minutes of leaching. In the case of ceramic waste, we achieved up to 98 % gold and 97 % silver extraction efficiency after only 45 minutes of leaching. In comparison with the classical cyanide leaching, thiourea leaching acts faster and without a harmful environmental impact.

Keywords: Waste, Gold, Silver, Crushing, Leaching.