Over the centuries, society has faced a number of natural resource challenges through a combination of three approaches: developing new sources, using resources more efficiently, and developing substitute materials. A recent resource challenge is to guarantee supplies of critical metals (CMs) that perform essential functions in modern engineered materials but are subject to short-term supply risks or concerns about longer-term availability. More specifically, by 2050 the EU consumption of critical raw materials (CRMs) for many technologies, like digital ones, is expected to increase by 70%.

The action “Critical Raw Materials Resilience: Charting a Path towards greater Security and Sustainability” of Horizon Europe promotes research and innovation on CRMs and waste processing, fixing the recycle target to 90%. The definition of CRMs or Critical Metals (CMs) applies particularly to the rare-earth elements (REEs), Sc, Ti, V, Co, Ga, Ge, Nb, Platinum Group Metals (PGMs), Hf, Ta, and W (EU report on critical raw material, 2023) and the 3rd European Raw Materials Scoreboard (European Commission 2021, Raw Materials Scoreboard) highlights urgency to strengthen the resilience and sustainability of raw materials supply in the EU.

The project pursues a low cost, sustainable circular economy approach since it deals with the CMs, especially REEs, in supergene natural mineral deposit types (bauxites) and in the residues of the Bayer process developed on bauxite ores (Red Muds, RM). The target is to enhance the knowledge on the processes promoting the concentration of CMs in such matrixes which is essential in the perspective of applying a strategic recovery and an efficient reuse, in view of their reintroduction as secondary raw materials in the economic cycle.

The CMs recovery will be performed via solid phase extraction (SPE) methods using novel sorbents while the RM residues, obtained from the CMs recovery, will be reused in the preparation of low cost and environment friendly construction materials by means of the Alkali Activation methodology, in the perspective of promoting waste minimization. The mineral deposits to be investigated are located in the Nurra area, NW Sardinia; whereas the RM are those stored at the Portovesme waste disposal, SW Sardinia.