The present communication deals with the leaching of gold and silver from the printed circuit boards (PCBs) of waste mobile phones using an effective and less hazardous system, i.e., a thiourea leaching process as an alternative to the conventional and toxic cyanide leaching of gold. The influence of particle size, thiourea and Fe(3+) concentrations and temperature on the leaching of gold and silver from waste mobile phones was investigated. Gold extraction was found to be enhanced in a PCBs particle size of 100 mesh with the solutions containing 24 g/L thiourea and Fe(3+) concentration of 0.6% under the room temperature. In this case, about 90% of gold and 50% of silver were leached by the reaction of 2h. The obtained data will be useful for the development of processes for the recycling of gold and silver from the PCBs of waste mobile phones.
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http://dx.doi.org/10.1016/j.wasman.2012.01.026 | DOI Listing |
J Hazard Mater
December 2024
Changchun Gold Research Institute Co., Ltd., Changchun 130012, China.
The eco-friendly treatment of cyanide tailings (CT) using microorganisms is a cost-effective and promising technology. However, this process often generates the secondary pollutants, such as ammonia nitrogen (NH-N), which can adversely impacts the surrounding environment. The accumulation of NH-N is also toxic to cyanide-degrading microorganisms, presenting a significant challenge in achieving simultaneous cyanide degradation and NH₄⁺-N mitigation.
View Article and Find Full Text PDFACS Omega
December 2024
TUBITAK UME, Chemistry Group Laboratories, 41470, Gebze, Kocaeli, Türkiye.
The continuous advancement of industry and technology has significantly increased electronic waste, which contributes to the depletion of valuable metal reserves. Therefore, it is crucial to recycle precious metals in electronic waste effectively and sustainably. This study introduces a novel approach by applying a carbazole-phosphazene-based polymer, EBE-06, in a two-stage leaching method for efficient metal extraction.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Department of Chemistry, Biology and Biotechnology, University of Perugia, 06123, Perugia, Italy.
We introduce the fragment-pairwise Local Energy Decomposition (fp-LED) scheme for precise quantification of individual interactions contributing to the binding energy of arbitrary chemical entities, such as protein-ligand binding energies, lattice energies of molecular crystals, or association energies of large biomolecular assemblies. Using fp-LED, we can assess whether the contribution to the binding energy arising from noncovalent interactions between pairs of molecular fragments in any chemical system is attractive or repulsive, and accurately quantify its magnitude at the coupled cluster level - commonly considered as the "gold standard" of computational chemistry. Such insights are crucial for advancing molecular and material design strategies in fields like catalysis and therapeutic development.
View Article and Find Full Text PDFEnviron Technol
November 2024
Institut National de la Recherche Scientifique (Centre Eau Terre Environnement), Université du Québec, Québec, Canada.
Discarded smartphones represent a valuable source of rare earths (REE), base metals and precious metals. This study focussed on the optimisation of three-stage selective leaching conditions for REE, copper and precious metals (Au and Ag), respectively, contained in printed circuit boards (PCBs) found in end-of-life smartphones. The effects of several leaching conditions, such as sulphuric acid and thiourea concentrations, were investigated using a statistical approach based on a design of experiments using Box-Behnken methodology.
View Article and Find Full Text PDFMaterials (Basel)
October 2024
Laboratory of Advanced Technologies in Non-Ferrous and Ferrous Metals Raw Materials Processing, Institute of New Materials and Technologies, Ural Federal University Named After the First President of Russia B.N. Yeltsin (UrFU), 620002 Yekaterinburg, Russia.
Autoclave leaching of sulfide concentrates may produce various ferric secondary phases, depending on the arsenic content and temperature. Silver is converted to argentojarosite, from which it is not recoverable by standard cyanidation methods. To increase silver recovery, it is necessary to reduce the argentojarosite formation during autoclave leaching.
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