Recovery Potential of Critical Raw Materials from Granite Quarry Waste: A case study from Buddusò (Sardinia, Italy)

In May 2024, the European Union introduced the Critical Raw Materials Act, a policy framework aimed at addressing the increasing demands for Critical Raw Materials and reducing dependence on external suppliers. In this context, this research focuses on the potential recovery of critical raw materials from ornamental granite extraction scraps produced at a quarry in Buddusò, Sardinia, Italy.

The volume and mass of the granite waste accumulated in the designated disposal zones of the quarry were estimated using Geographic Information Systems and Digital Elevation Models. Subsequently, the characterization of the granite waste by Scanning Electron Microscopy confirmed the presence of allanite, a rare earth mineral rich in light rare earth elements, such as cerium, lanthanum, and neodymium. Following that, a combination of gravity and magnetic separation techniques was used to recover enriched fractions containing significant amounts of rare earth elements, scandium and gallium, with concentrations that could be economically relevant for industrial applications.

This study highlights the economic potential of REEs recovery from granite extractive waste and assesses the feasibility of integrating these processes into broader industrial contexts. Preliminary market analysis indicates that, under optimized operating conditions, the recovery of critical raw materials from this type of waste could achieve significant profitability. The extension of such studies to other quarries in the region could provide a robust basis for the creation of a district recycling hub, in line with the European Union's objective of improving the resilience and sustainability of its critical raw materials supply chain.