Waste electrical and electronic equipment (WEEE) contains economically significant levels of precious, critical metals and rare earth elements, apart from base metals and other toxic compounds. Recycling and recovery of critical elements from WEEEs using a cost-effective technology are now one of the top priorities in metallurgy due to the rapid depletion of their natural resources. More than 150 publications on WEEE management, leaching and recovery of metals from WEEE were reviewed in this work, with special emphasize on the recent research (2015–2018). This paper summarizes the recent progress regarding various hydrometallurgical processes for the leaching of critical elements from WEEEs. Various methodologies and techniques for critical elements selective recovery (using ionic liquids, solvent extraction, electrowinning, adsorption, and precipitation) from the WEEEs leachates are discussed. Future prospects regarding the use of WEEEs as secondary resources for critical raw materials and its techno-economical and commercial beneficiaries are discussed. GRAPHICAL ABSTRACT Pictorial representation of the hydrometallurgical recovery of critical and precious elements from WEEE

In this paper the most recent advances in lithium iron phosphate batteries recycling are presented. After discharging operations and safe dismantling and pretreatments, the recovery of materials from the active materials is mainly performed via hydrometallurgical processes. Moreover, a significant number of works are currently being focused on direct regeneration processes. Both approaches are currently applied only at laboratory scale. The main challenges to be faced when dealing with upscaling these technologies (for example mechanic vs manual dismantling, valuable elements recovery strategy vs all-components recovery strategy) are here presented and discussed.

Existing desalination technologies produce large amount of waste brines with higher salinity concentration than feed seawater, the disposal of which pose serious environmental problems. At the same time, waste brines represent a valuable source of strategic materials—such as magnesium—and therefore their valorization offers the opportunity to overtake both the environmental and the economic issues. Current needs are to identify gaps and challenges to recover secondary magnesium in order to bring recovery technologies closer to the market for potential commercial applications. In this technical review, the available methods for magnesium recovery from seawater desalination brines are described and compared in details, to provide the readers with a wide overview to better address their research efforts towards resources valorization, in accordance with the circular economy principles. Graphical abstract