Hydrometallurgical recovery of critical metals from WEEE shredding dust

The recycling of metals from Waste Electrical and Electronic Equipment (WEEE) can be regarded as a relevant economic opportunity as the industry of electronic devices is a large consumer of both base and special metals. Significant portions of precious metals and rare earth elements contained in WEEE are however lost in recycling treatments, especially through dust stream originating from shredding and other separation steps involved in mechanical processes. The management of this dust fraction concerns both economic and environmental issues as it is currently disposed of in landfill. If the occurrence of hazardous substances is a matter of environmental concern, on the other hand the presence in dust of reasonable concentrations of valuable metals makes this matrix a potential attractive source of secondary materials. Nevertheless, research studies on refining treatments for critical metal recovery from WEEE shredding dust have not been reported yet. The present study aimed at investigating the potential application of refining processes to dust materials originating from a full scale WEEE treatment plant. For this purpose, a chemical leaching process was carried out and the optimization of the operating parameters was discussed. The leaching capacity of selected metals was evaluated and a hydrometallurgical approach was proposed for valuable and critical metal recovery from dust waste.