Bauxite Residue Reuse Through Combined Operations: Industrial Pilot Modules

Bauxite residue’ (BR) refers to the insoluble solid material, generated during the extraction of alumina (Al₂O₃) from Bauxite ore using the Bayer process. As the global demand for primary aluminium metal increases so does the BR production, currently in excess of 150 million tonnes per year (worldwide). This is generated at some 60 active alumina refining plants. In addition, there are at least another 50 closed legacy sites, so the combined stockpile of bauxite residue at active and legacy sites is estimated at between three and four thousand million tons. MYTILINEOS’ since 1991 has been pioneering research on BR handling and reuse, focusing initially on massive low value applications such as use as a raw material for cement clinker production, iron production, bricks and tile production, soil and road substrate and others. From such approaches, only re-use in the cement sector has found industrial application leading to a current recycling of a 10 % of the annual BR production in various cement plants in Greece and Cyprus. To increase the BR reuse potential, MYTILINEOS and NTUA investigate BR-centric processes aiming to recover iron, aluminium, sodium and scandium from BR in a near-zero waste and break-even processing flowsheet which could be applied in a context of industrial symbiosis. To this end, lab-scale and industrial pilot scale research are combined to produce reliable data that will allow a comprehensive techno-economic evaluation that can lead to a viable solution. This paper will present several stand-alone processes and provide insight on the possibilities of interconnecting them.