Session Sheet - Bauxite Residue Valorization and Best Practices: Recovery of Steel, Titania and Rare Earths

Bauxite Residue Valorization and Best Practices: Recovery of Steel, Titania and Rare Earths
Sponsored by: TMS Light Metals Division, TMS: Aluminum Committee
Program Organizers: Tobias Hertel, Ku Leuven; Christina Meskers, SINTEF; Efthymios Balomenos, Metlen Energy and Metals; Casper Van Der Eijk, SINTEF; Brajendra Mishra, Worcester Polytechnic Institute; Yiannis Pontikes, Ku Leuven R&D

Wednesday 2:25 PM
March 26, 2025
Room: 111
Location: MGM Grand

Session Chair: Yiannis Pontikes, Ku Leuven R&D

2:25 PM  Invited
Recovery of Titanium from Production Residues via Physical and Chemical Processing: Sharon Djinigou¹; Bengi Yagmurlu¹; ¹Technical University Clausthal
     Titanium, renowned for its material properties, is a significant resource for several industries, specifically aerospace and medical. However, with rising concerns about the availability and sustainability of titanium arising from the Russian-Ukrainian conflict, recycling has gained importance for securing the supply of this critical metal. The EURO-TITAN project unlocks sustainable titanium resources through the valorization of bauxite residues and titanium dioxide production waste, while decarbonizing the process, via the use of green-hydrogen technologies. The resulting slag, containing up-concentrated titanium, is further treated using physical, physicochemical, and hydrometallurgical processes. In this study, titanium-bearing phases were up-concentrated via density separation techniques, such as falcon concentrator and wet shaking table, to separate the titanium-bearing heavy and the silicon-bearing light phases. Integrating physical enrichment processes enhance the recovery rates while decreasing the chemical consumption significantly due to the separation of the reactive portion of the material, thus contributing to circular economy principles.

2:45 PM Question and Answer Period

2:50 PM
Red Mud to Produce Sustainable Iron and Steel - A Thermodynamic Analysis: Rangasayee Kannan¹; Adam Stevens¹; Peeyush Nandwana¹; ¹Oak Ridge National Laboratory
    With the imminent need to decarbonize the iron and steel sector, this talk will highlight the potential of re-integrating red mud/bauxite residue, an industrial waste product generated during the processing of bauxite to extract alumina into the manufacturing chain to produce iron and steel as a flux. The thermodynamic feasibility of using red mud as a flux in the presence of different reducing agents will be discussed. Potential approaches to decarbonizing iron and steel production while utilizing red mud as a flux, as well as the benefits of red mud remaining after iron extraction will be discussed.

3:10 PM Question and Answer Period

3:15 PM
Synergistic Pyrolysis with Refuse-Derived Fuel (RDF) Can Neutralize Bauxite Residue (BR): Roberto Seno¹; Rodrigo Moreno¹; Fabio Yamaji²; Maria Veloso²; ¹CBA; ²UFSCar
    The high alkalinity of Bauxite Residue (BR) presents technical and economic challenges for its reuse. This study investigated the alkaline neutralization of BR through synergistic pyrolysis with products from Refuse-Derived Fuel (RDF). Two types of RDF were used along with BR from CBA’s alumina refinery in Brazil. Various mass proportions (0, 10, 20, and 50% w/w) of RDF were employed for synergistic pyrolysis. Pyrolysis was conducted at temperatures of 200, 400, 600, and 800 慢 using a muffle furnace and crucibles, with a residence time of 20 minutes. The pH of the mixtures after pyrolysis decreased as the proportion of RDF increased. Results indicated that neutralization of BR occurred at temperatures of 200 and 400 慢. The best performance was observed with 50% RDF at 400 慢, achieving a final pH of 8. Synergistic pyrolysis of BR and RDF effectively reduced the alkaline content of the bauxite residue.

3:35 PM Question and Answer Period

3:40 PM Break

3:55 PM
Utilizing Mining Tailings for Sustainable Steel and Rare Earth Element Recovery: Duhan Zhang¹; ¹Massachusetts Institute of Technology
     Rare earth elements (REEs) are vital for advanced energy and defense technologies. The U.S. has an estimated 13 million tons of REE ore reserves, but high-grade deposits are scarce. REE-containing tailings accumulate, with REE value in red mud estimated at $796 per ton. However, extracting REEs from these sources is difficult due to their entrapment in a mineral matrix, typically iron oxide.We propose a novel process to recover REEs from tailings and low-grade deposits, involving electro-metallurgically removing iron oxide, hydro-metallurgically extracting aluminum salt, and separating REEs. This yields refinable REE concentrates, emissions-free pure iron metal, and supplementary cementitious materials, contributing to steel and cement industries’ decarbonization. By tackling associated economic and environmental issues, our approach provides a sustainable solution for unlocking the potential of domestic rare earth resources. It offers a pathway to utilize mining waste effectively, producing valuable materials while supporting green technology and reducing environmental impact.

4:15 PM Question and Answer Period

4:20 PM Panel Discussion

4:50 PM Concluding Comments