Departement Materiaalkunde (MTM)
Tobias Hertel won the Best Paper Award at the Bauxite Residue Valorisation and Best Practices Conference (5-7 October, Leuven) with his paper A proposal for a 100 % use of bauxite residue: the process, results on the novel Fe-rich binder and how this can take place within the alumina refinery.
In this work a new pyro-process is presented to transform bauxite residue (BR) into a suitable Fe-rich precursor material for the synthesis of inorganic polymers. Based on thermodynamic calculations, this was achieved by introducing C and firing at 1100 °C, which leads to a carbothermic reduction of iron oxides, present in BR, into ferrous iron, which supports the formation of liquid phase. Addition of silica was also investigated, as it enhances the amount of liquid slag phase. The resulting material after the heat treatment, was mixed with a K-silicate solution and cured at 60 °C for 72h. The final materials are water insoluble and dense, demonstrating compressive strength >40 MPa. These inorganic polymers can find applications in construction, such as pavement or floor tiles. The work is concluding with a presentation on how the process to transform BR can take place within the alumina refinery, by adapting existing installations.