From trash to resource: a green approach to noble-metals dissolution and recovery

Green Processing and Synthesis

article

Angela Serpe¹  Flavia Artizzu¹  Davide Espa¹  Americo Rigoldi¹  Maria Laura Mercuri¹  Paola Deplano¹ 

[1] Dipartimento di Scienze Chimiche e Geologiche, Università di Cagliari I-09042 Monserrato;3R Metals Ltd, Spin-off of the University of Cagliari, at the Dipartimento di Scienze Chimiche e Geologiche, Università di Cagliari I-09042 Monserrato

关键词: gold;    leaching;    PCBs;    recycling;    WEEE;   

DOI  :  10.1515/gps-2014-0004

来源: De Gruyter

【 摘 要 】

A process based on the lixiviant properties of organic mixtures of dihalogen/S,S-ligands, N,N′-dimethyl-perhydrodiazepine-2,3-dithione (Me 2 dazdt) and tetraalkylthiuramdisulphide (Et 4 TDS) in the presence of diiodine, for gold recovery from the non-ferrous metal fraction of real shredded waste electric and electronic equipment (WEEE), is presented here. Selective dissolution of metals is achieved through a sequence of three steps where the oxidation of different kinds of metals is achieved by using: (1) refluxing water solutions of HCl 1:5 under Ar atmosphere (Sn, Zn, etc.); (2) water solutions of NH 3 /(NH 4 ) 2 SO 4 mixtures in the presence of H 2 O 2 on the resting sample (Cu, Ag); and (3) acetone solutions of Me 2 dazdt or Et 4 TDS/I 2 mixtures on the final residue (Au). Each step is followed by a further treatment for: (1) metal recovery, in the case of Au, Cu, Ag; and (2) inertization, in the case of heavy metals. As a whole, the process is very promising for effective recovery of gold and other valuable noble-metals and for using non harmful reagents in mild conditions.

【 授权许可】

CC BY