Recovery opportunities of valuable and critical elements from WEEE treatment residues by hydrometallurgical processes
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Due to the increasing demand of metals by industry and the limited availability of natural resources, the secondary supply of these elements from discarded products, such as waste electrical and electronic equipment (WEEE), is an important strategy for pursuing a sustainable development. Nevertheless, the complex and heterogeneous composition of this waste stream stands as one of the main drawbacks in the definition of innovative recovery processes. This study investigated the recovery potential of a multi-step leaching process to extract the strategic metals, namely precious metals and rare earth elements (REEs), from the dust produced during the industrial shredding treatment of WEEE. Using a first double-oxidative step with sulfuric acid, most rare earth elements contained in the dust were dissolved at high percentages. Moreover, around 50% of gold was extracted in a second leaching step using 0.25 M thiourea, in a solid to liquid ratio of 0.2 g/70 mL, at 600 rpm. In this regard, the optimum operating conditions were studied by a 23 full factorial design. Experimental results address the definition of a novel approach, pursuing the recovery of resources of great industrial interest from the residues originating from WEEE mechanical treatments typically performed at large scale. As this dust fraction is not sent for recovery but currently disposed, the proposed recycling strategy promotes the diversion of waste from landfill while reducing the need for virgin materials via lower-impact metallurgical processes.
KeywordsElectrical and electronic waste Shredding dust Rare earth elements Precious metals Chemical leaching Circular economy
The authors wish to thank the plant manager and the staff of the WEEE treatment facility for the sampling support. The technical support of Melania Arenas Morente as well as the analytical assistance at the SEED laboratory of Anna Farina and Paolo Napodano were deeply appreciated.
The research study was partially funded by a FARB project of the University of Salerno.
- Bakas I, Fischer C, Haselsteiner S et al (2014) Present and potential future recycling of critical metals in WEEE. Copenaghen Resource Institute (ED), Copenaghen, DenmarkGoogle Scholar
- De Michelis I, Kopacek B (2018) HydroWEEE project: design and construction of a mobile demonstration plant. In: Vegliò F, Birloaga I (eds) Waste electrical and electronic equipment Recycling. Aqueous recovery methods. Woodhead Publishin, pp 357–383Google Scholar
- Deveci H, Yazici E, Aydin U, Akcil A (2010) Extraction of copper from scrap TV boards by Sulphuric acid leaching under Oxidising conditionsGoogle Scholar
- European Commission (2017) Study on the review of the list of critical raw materials. Crit Assess. ISBN 978-92-79-47937-3. https://doi.org/10.2873/876644
- Gurung M, Adhikari BB, Kawakita H, Ohto K, Inoue K, Alam S (2013) Recovery of gold and silver from spent mobile phones by means of acidothiourea leaching followed by adsorption using biosorbent prepared from persimmon tannin. Hydrometallurgy 133:84–93. https://doi.org/10.1016/j.hydromet.2012.12.003 CrossRefGoogle Scholar
- Hagelüken C (2006) Recycling of electronic scrap at Umicore precious metals refining. Acta Metall Slovaca 12:111–120Google Scholar
- Innocenzi V, Ippolito NM, De Michelis I et al (2016) A hydrometallurgical process for the recovery of terbium from fluorescent lamps: experimental design, optimization of acid leaching process and process analysis. J Environ Manag 184:552–559. https://doi.org/10.1016/j.jenvman.2016.10.026 CrossRefGoogle Scholar
- Montgomery DC (1991) Design and analysis of experiments, third edn. Wiley & SonsGoogle Scholar
- Nicol MJ, Paul RL, Fleming CA (1987) The chemistry of the extraction of gold. MintekGoogle Scholar
- Oliveira PC, Cabral M, Taborda FC et al (2009) Leaching studies for metals recovery from printed cir cuit boards scrap. CM AG, TorontoGoogle Scholar
- Tsamis A, Coyne M (2015) Recovery of rare earths from electronic wastes: an opportunity for high-tech SMEs. Dir Gen Intern POLICIES POLICY Dep Econ Sci POLICYGoogle Scholar
- Tunsu C, Retegan T (2016) Chapter 6 - hydrometallurgical processes for the recovery of metals from WEEE. In: WEEE Recycling. Elsevier, pp 139–175Google Scholar
- Tunsu C, Petranikova M, Gergorić M, Ekberg C, Retegan T (2015) Reclaiming rare earth elements from end-of-life products: a review of the perspectives for urban mining using hydrometallurgical unit operations. Hydrometallurgy 156:239–258. https://doi.org/10.1016/j.hydromet.2015.06.007 CrossRefGoogle Scholar
- UNEP (2013) Recycling Rates of Metals – A Status Report, A Report of the Working Group on the Global Metal Flows to the International Resource Panel. Graedel TE, Allwood J, Birat J-P, Reck BK, Sibley SF, Sonnemann G, Buchert M, Hagelüken C (eds)Google Scholar