Speaker
Description
In the face of 28 million tonnes of spent refractories annually, recycling and upcycling strategies for MgO-C refractories are crucial to more sustainable and environmentally friendly materials management in high-temperature industries. The research training group GRK 2802 funded by the German Research Foundation (DFG) investigates two core ideas addressing the use of spent MgO-C.
The recycling idea aims to combine spent MgO-C with fresh fused MgO, graphite, and a novel environmental friendly binder system replacing the carcinogenic and hazardous conventional binders. In our project, Raman spectroscopy is applied to characterize the carbon structures in the novel binders and their transformation during pyrolysis at temperatures up to 1000°C. Raman spectroscopy allows for assessing the ratio between sp2- and sp3-hybridized carbon, the hydrogen content and the average sp2 carbon cluster size evaluating the binder performance.
The upcycling idea intends to develop a low/no carbon anode material for aluminum production. Substituting graphite electrodes by an MgO-steel composite would reduce the CO2 emission of the fused-salt electrolysis. During a pre-oxidation step in the production of the MgO-steel composite, different spinel phases are formed improving the corrosion resistance of the anode. As Raman spectroscopy is sensitive to cation disorder in spinel systems, it is employed to identify phases - right now in model spinel systems and in the future also in fresh and used MgO-steel anodes.
Finally, the application of the laser excitation to MgO-C itself reveals defect-related photoluminescence (PL) bands with phonon sidebands. The poster gives an overview on all three aforementioned use cases highlighting the potential of Raman and PL spectroscopy in refractory material science.
