Novel technologies and conventional processes for recovery of metals from waste electrical and electronic equipment: Challenges & opportunities - A review

Challenges of sustainable development, particularly 'living within limited infinity' and 'scarcity of natural resources' have urged scientific community to develop innovative processes that integrate into complex technology and reduce ecological disturbances. Present study provides a state-of-art review on waste electrical and electronic equipment (WEEE) ranging from an analysis of relevance, government initiatives, management strategies, conventional methods of metal recovery and novel alternatives. WEEE generation and its management tools have been a subject to various review articles, however resource(s) recovery from WEEE has not been hashed out intricately in literature. Presence of significant amount of precious/rare metals makes WEEE a secondary resource of metals and therefore warrants special attention relative to general solid waste management strategies. Various hydrometallurgical and pyrometallurgical approaches have been reported for efficient metal recovery from WEEE; still a decisive assessment of conventional approaches has not been sufficiently explicated. Therefore, a comprehensive analysis of literature is essentially necessitated in order to create a common framework of knowledge in this emerging research area. This review article critically analyses the technical feasibility of conventional practices for metal recovery from WEEE and suggests that conventional processes may not meet the industrial feasibility because of secondary pollution possibilities and high economics. Hence, emerging trends in the field of metal extraction from WEEE have been discussed which has not been reviewed yet, to the best of our knowledge, in any review articles. It is believed that this review may provide an insight to look into novel technologies such as chelation technology, use of ionic liquids, and other alternative technologies for resource optimization and waste management.