The Critical Raw Materials Potential of Anthropogenic Deposits: Insights from Solid Residues of Municipal Waste Incineration

Abstract

Due to the current and foreseen global growth of raw material demand, the sustainable supply of minerals and metals for high-tech applications, the so-called critical raw materials (Co, Cr, Ga, Nb, Rare Earth Elements, Sb, W, Platinum Group Elements), is of general concern. Industrial wastes have the potential to become an alternative source (flow) of strategic metals and, consequently, their valorisation can be seen as a move towards resources efficiency and circular economy. In this 3-years study I aimed to decipher the critical raw materials potential from solid residues produced by Municipal Solid Waste Incineration (MSWI), namely bottom and fly ashes. These solid residues, coming from different leading companies of MSWI in northern Italy, have been selected because they can be accounted for urban mining purposes and represent high elements flows, still poorly explored. In the present work I address the potential of MSWI solid residues as an alternative source of critical raw materials by studying the material chemistry, its resources flow and the evaluation of metals upgrading and recovery. Finally, I tackle some environmental and economic issues.