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European Training Network for Zero-waste Valorisation of Bauxite Residue (Red Mud)

Periodic Reporting for period 2 - REDMUD (European Training Network for Zero-waste Valorisation of Bauxite Residue (Red Mud))

Reporting period: 2016-12-01 to 2019-10-31

To tackle its (critical) raw material dependency, Europe needs comprehensive strategies based on sustainable primary mining, substitution and recycling. Freshly produced flows and stocks of landfilled industrial residues, such as bauxite residue (BR, a by-product of alumina production from bauxite ore and also known as “red mud”), can provide major amounts of critical metals and, concurrently, minerals for low-carbon building materials. This is self-evident considering the present BR production level in the EU is > 5 Mtonnes/year whereas the cumulative stockpiled level is staggering > 200 Mtonnes (dry matter). BR is a huge secondary source for critical raw materials which are considered key to the clean technologies of tomorrow (electric cars, wind turbines, solar panels, batteries, etc), and hence highly valuable for the European economy, modern technology and environment. The increasing demand for raw materials, their price volatility (e.g. rare-earth elements, REEs) and the market distortions imposed by some countries, confront Europe with a number of challenges, along the entire raw materials value chain.

Overall objectives and Challenges
REDMUD trained 15 early stage researchers (ESRs) in the science and technology of BR valorisation. The project investigated innovative, eco-friendly and integrated methods for the metal recovery, while valorising the residuals into building materials. An intersectoral and interdisciplinary collaboration of EU-leading institutes and scientists was established, which covered the full value chain: from BR to recovered metals and new building materials. Research challenges include the development of efficient extraction of iron, aluminium, titanium and rare earths (including scandium) from distinct (NORM classified) BRs and the preparation of new building materials with higher than usual iron content.

Consortium
REDMUD drew its talents from 9 Beneficiaries, including 6 Research Institutes (KU Leuven (coordinator), UHelsinki, RWTH Aachen, KTH, NTUA, UTartu) and 3 Companies (MEAB, Aluminium of Greece/Mytilinaios, Titan). Concurrently, REDMUD is strengthened with 4 additional Partner Organisations (UPatras, UAveiro, Bay Zoltan, Szikkti Labor) as well as an Advisory Board.

REDMUD contained 7 WPs, 4 of which are Research Activities:
WP1: Fe and Al removal from BR
WP2: Ti and REEs removal from BR
WP3: Cementitious binders from BR
WP4: LCA, NORM and characterisation of bauxite ores and residues
WP5: Training
WP6: Exploitation, dissemination and outreach
WP7: Management

Conclusions
The REDMUD project has shown that (near-)zero waste valorisation of BR is technological feasible. Different innovative flowsheets have been developed to use BR as a secondary resource for iron, aluminium, titanium, and the rare-earth elements (including scandium), and to use the solid residue that is left behind after recovery of the metals, in new building materials. The main obstacles for the practical implementation of the flow sheets in industry are the high processing costs compared to the intrinsic value of the metals in BR and the strict regulations for use of NORM in building materials. The REDMUD project provided an excellent training to 15 young researchers so that they will be able to make valuable contributions to the European industry and academia in the future.
The results are covering: (a) carbothermic reduction, microwave-assisted reduction and direct electro-reduction for iron recovery; (b) an eco-friendly, optimised Al recovery process; (c) a leaching process to selectively recover titanium and REEs (incl. scandium); (d) methods of process intensification to improve leaching of minor and trace metals; (e) processes to recover metals by supported ionic liquid phases, inorganic ion exchangers or selective precipitation; (f) methods to synthesise iron-rich, low-carbon cements with novel properties; (g) methodology on the fate of different BR elements in the valorisation flowsheet(s); (h) advanced radiological assessment methods on the reuse of BR NORM residues as building materials; (i) a comprehensive LCA analysis for the REDMUD valorisation flow sheets, integrating risk assessment; (j) a framework that integrates NORM into the LCA methodology. By the collaboration between the researchers, technological barriers were tackled and closed-loop, environmentally-friendly, recovery flow sheets were developed.

These outcomes were communicated in the scientific, industrial and policymaking community, through the project's dedicated website (http://etn.redmud.org) and conferences (BR2015 in Leuven and BR2018 in Athens, http://conference.redmud.org/) its 3-days summer school in 2016, peer-reviewed papers, technical brochures, the LinkedIn Red Mud Project group as well as other social media, such as Facebook and Twitter. Moreover, newsletters were sent periodically, including policy briefs for European (and national) policy makers. Other initiatives, e.g. the workshop of the Aluminium Innovation Hub, on the 31st of May 2016, at KU Leuven, or the KIC Raw Materials idea camp/matching event on 21-22 of September 2016, at Aughinish, were also contributing in the overall impact by facilitating the distribution of the results and by shaping a community around BR valorisation.
Several innovative flowsheet for processing of BR were developed, both as part of the individual ESR projects and as a result of collaborative work between different ESRs. For instance, several pyrometallurgical processes were developed to remove iron as metallic iron from BR, while enriching the REEs in the slags. The REE-enriched slags could be further processed by hydrometallurgical and ionometallurgical methods to recover these REEs. New adsorbents were prepared for recovery of valuable metals from leachates and for their separation. Innovative iron-rich cements and inorganic polymers were created. Insights were gained into the mass flows of the different metals in the Bayer process and on the different mineralogical phases in which metals are incorporated in BR. For the first time. LCA methodology has been extended to include NORM.

In terms of impact, the project contributed to the policy objectives outlined in the Raw Materials Initiative, the EIT KIC RawMaterials and the Strategic Innovation Agenda of the EIP on Raw Materials. Furthermore, as the recovered minerals are used to produce low-carbon binders that may partly replace carbon-intensive Portland cement, REDMUD contributed to lowering the EU’s climate footprint. In addition to the above, the project leads to new recommendations for the strategic orientation of the EU’s Raw Materials Policy and the associated Directives.

The research done by the ESRs in the REDMUD project is continued in several new Horizon2020 projects at a higher TRL level (RIA, IA and EIT KIC upscaling projects), such as SCALE (http://scale-project.eu/) RemovAL (https://www.removal-project.com/) and RECOVER (https://recover.technology/).
Geographical distribution of REDMUD partners
REDMUD general workflow