A critical review of the pre-processing and metals recovery methods from e-wastes

E-wastes being potential sources of numerous valuable metals are promoted to undergo recycling and recovery under the umbrella of urban mining and circular economy. Thus, the present study provides a critical review of the technological details of different metal recycling processes, pre-treatment methods, and the advancements made in these techniques. Critical evaluation of different metal recovery techniques has also been presented based on the available life cycle assessment (LCA), techno-economic, and industrial-scale studies. The study revealed that the integrated metal recovery techniques serve better in terms of recovery efficiency and envi-ronmental performance than any single recovery technique. Also, scaling up of biometallurgical, electro-chemical, and super critical fluid extraction methods needs to be promoted due to their better environmental performances.