(412d) Process Intensification for Continuous Metal Extraction from E-Waste: Challenges and Opportunities

E-waste proper disposal and treatment is a global, inter-regional and domestic problem and has been a topic of research for the last two decades. Owing to the unparalleled replacement rate of small electronic items, Waste Electrical and Electronic Equipment (WEEE) is predicted to increase 75 million tonnes in 2030 and at the same time exhausting the conventional sources of valuable metals such as rare earth elements (REE), platinum group metals (PGMs), and Co, Sb, Mo, Li, Ni, Cu, Ag, Sn, Au, Cr. Printed Circuit Boards (PCBs) being the main part in WEEE contain nearly 28% metals (containing both environmentally harmful metals like Cr, As, Hg and valuable metals like Ag, Au, Pt, Co, Ni) having 10 times higher purity as compared to rich-content mineral ores. To manage e-waste and to reduce the possibility of a metal shortage, e-waste should be viewed as a resource to be exploited. Thus, development of new sustainable pathways and techniques for E-waste management, recovery, and reuse of valuable elements are required for ‘elemental sustainability’. Most of the existing methods utilized for E-waste recycling, recovery and disposal are improper and result in environmental contamination (soil, air and water) releasing hazardous and toxic chemicals into the environment. The recovery of metals from WEEE via conventional processes (hydro-metallurgy and pyro-metallurgy) has been thoroughly documented in the literature. However, their widespread use has negative environmental consequences and high energy requirements. The objective of this paper is to review technologies employed in continuous metal extraction and their advantages over batch operations using microfluidic devices with the PI approach. Microfluidic devices offer an alternative in the solvent extraction at the micro-level offering a higher mass and heat transfer rate as compared to other conventional devices. Also, the micro-flow device are safe, can easily handle toxic chemicals, energy-efficient, environmentally stable and may be a potential technology/method for large scale recovery of metals from E-waste. This paper discusses recent advances in metal recovery from WEEE utilizing Solvent Extraction techniques, which could help with industrial compacting and transition.