Bauxite residue (red mud) is the waste of alumina production from bauxite by the Bayer process (hot digestion with caustic soda). An estimated 4.4 billion tonnes of BR have been deposited worldwide by 2018, and approx. 50 million tonnes are stored in Hungary. In recent years the recovery of economically important elements, such as Sc, Ga, Ti, V and rare earth elements (REEs), has gained interest due to the increasing demand for critical raw materials (CRMs) in Europe with increasing supply risk. These elements are essential for the high-tech and low-carbon industries (e.g. LEDs, smartphones, windmills, electric cars) for our modern lives. Bauxite residue is an ideal resource for CRMs, however, we need green (e.g. low energy intensive) technologies to recover CRMs. Biotechnological approaches show advantages compared to pyro- and hydrometallurgical processes, e.g. lower temperatures, less chemical consumption, and lower costs. Bioleaching (biomining) applies microorganisms to solubilise metals from hardly soluble substrates, such as low-grade ores. This project aims to understand the mechanisms of bioleaching processes for the leaching of targeted CRMs by fungi and bacteria from bauxite residue. We will also investigate the microbial composition of bauxite residues from Hungary and Europe and isolate microbial strains with potential biotechnological applications. We will assess the characteristics of the leaching residue and its reusability. The results may contribute to the supply of Hungary and Europe’s CRM demand and the development of bio-based bauxite residue processing technologies.   

Funding: National Research and Innovation Office, OTKA FK 146542: Mechanisms of critical raw materials bioleaching from bauxite residue project

Project leader: Dr. Viktória Feigl

Duration: 01.01.2024-31.012.2027.