How can critical raw materials (CRMs) be recovered from mining residues, industrial by-products and end-of-life products? This question brought experts together for the REMHub webinar CRM Recovery from Industrial and Mining Side Streams: Exploration of the Value Chains on 14 October 2026. The speakers explored a range of approaches, from hydrometallurgical processes and bioleaching to membrane technologies and selective filtration.
Recovering CRMs from secondary sources requires more than identifying valuable elements. Ivano Menso from Minerali Industriali highlighted the importance of assessing geological, technical, economic and site-specific conditions, and designing an integrated process that considers both the material and the final product.
Several presentations focused on specific industrial residues and waste streams. Maurizio Bellotto from Opigeo discussed an approach to recovering CRMs from red mud, a residue of bauxite processing. The process combines acid leaching, roasting and adsorption to concentrate target elements, while also exploring the valorisation of the remaining iron-bearing residue.
Astrid Laidna from BiotaTec explored bioleaching for recovering rare earth elements (REEs) from phosphogypsum, a by-product of the fertiliser industry. Tests achieved REE leaching rates of 60–90% in less than 24 hours. Further work will address scale-up, contaminant removal and the assessment of the process’s economic and environmental performance.
Opportunities also exist in titanium dioxide production. Domen Slemenšek from Cinkarna described work on recovering scandium, vanadium and iron from production streams. A key challenge in scandium recovery is separating it from competing elements such as iron, aluminium and titanium.
Other speakers examined technologies for extracting valuable materials from complex feeds. Pietro Romano and Francesco Vegliò from the University of L’Aquila described hydrometallurgical processes for recovering REEs from permanent magnets, spent fluorescent lamps and solid oxide electrolyser cells. Their work includes processes achieving high recovery rates and product purity, as well as a mobile pilot that enables trials at waste sites.
Nora Jullok from the University of Oulu explored membrane technologies for CRM recovery, including nanofiltration, electrodialysis and affinity membranes. She highlighted the challenges of separating chemically similar rare earth elements and the importance of considering membrane performance within the wider process, including feed preparation, fouling and downstream treatment.
A different approach was introduced by Timo Galkin from Weeefiner and Riina Ahtiainen from Terrafame. Their 4D Scavenger technology uses 3D-printed, chemically functional filters to selectively capture dissolved rare earth elements from industrial process streams. The REMHub demonstrator at Terrafame has produced pilot results consistent with laboratory tests.
Continuing the work on CRM recovery
The webinar showcased different approaches to recovering CRMs from industrial and mining side streams, each with its own process requirements and technical challenges. Ongoing work includes improving selectivity and product quality, testing technologies at larger scales, and assessing how individual recovery steps can be integrated into practical process flows.
Through these examples, REMHub continues to explore technologies and value chains for recovering critical raw materials from secondary sources.