期刊
JOURNAL OF CLEANER PRODUCTION
卷 278, 期 -, 页码 -出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.jclepro.2020.123597
关键词
Gold recycling; Mild aqua regia; Printed circuit board; Waste electronics; Mechanism study
资金
- National Natural Science Foundation of China [21806102, 51474146]
- Shanghai Sailing Program [18YF1408800]
- Gaoyuan Discipline of Shanghai e Environmental Science and Engineering (Resource Recycling Science and Engineering)
In this study, gold was easily recycled from waste mobile phones using a DMF-CuCl2-CaCl2 system, without the need for pretreatments or an enrichment process, and the reaction system could be cyclically utilized. After parameter optimization, the gold leaching rate and precipitation rate could reach over 99%. DMF played a significant role in the leaching system.
Traditional mechanical pretreatment and hydrometallurgy is the mainstream technology to recycle gold from waste printed circuit boards (PCBs). However, this method is cumbersome and often employs toxic/harsh chemicals. In the present study, gold was easily recycled from PCBs gold-plated layer of waste mobile phones (WMPs) in DMF-CuCl2-CaCl2 (DMF: dimethyl formamide) system what we call mild aqua regia without pretreatments or enrichment process, and the reaction system could be cyclic utilized. In such reaction system, gold could be recycled through leaching, precipitation and filtration. The reaction parameter optimization and reaction mechanisms were studied. Under the optimized conditions, the gold leaching rate and precipitation rate could reach over 99%. DMF plays a significant role in the leaching system. As a typical polar aprotic solvent, DMF cannot solvate Cl-. Thus, Cl- exists in a naked state, and it can easily react with Au. Besides, Au (III) could generate a complex through the complexation with DMF which could result in the redox potentials reduce and move the equilibrium to the Au leaching side. In summary, this study provided a fundamental basis as well as practical guidance for recovering precious metals from waste electrical and electronic equipment in an efficient manner. (C) 2020 The Authors. Published by Elsevier Ltd.
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