Gehre, PatrickGunasekar, Dinesh KumarHubálková, JanaAneziris, Christos2026-09-252026-09-252026-09-25https://opara.zih.tu-dresden.de/handle/123456789/2959https://doi.org/10.25532/OPARA-1578Every year, approx. 28 million tons of used refractories accrue worldwide. After their break out, the majority of them are used in subordinate application fields such as aggregates for road construction (downcycling) or deposited in landfills. Their recycling in the field of refractory materials played an underpart so far. For ecological and economic reasons, an increased research potential was identified in the last years consecrated to increasing the recycling rate of refractories and finding new markets and application fields with higher value for them. The study presents current findings of a long-term research training group addressing (amongst others) the development of MgO-C ladle bricks containing MgO-C recyclates and being bonded with pitch- and resin-free environmentally friendly binders. So far, the favored batches contained an oxidic grain fraction composed of 40.5 wt.-% fused MgO raw material, 40.5 wt.-% MgO-C recyclates, 14 wt.-% sintered magnesia (DBM) raw material together with 5 wt.-% graphite and optional antioxidants (TiO2, Al, SiO2). A binder system composed of a mixture of lignin, collagen, and polyethylene glycol (PEG) was developed. The latter served as a pressing aid and was necessary due to the absence of liquid resin in the batch. Even after a considerable and auspicious optimization during previous studies, this basic batch containing recyclates and no pitch or resin does not meet the physical and mechanical properties of standard industrial bricks. Hence, in the present study, the binder system was enhanced by using varying amounts of lignin, collagen, and tannin together with polyethylene glycol, fructose, and citric acid addition. The new developed MgO-C mixtures were pressed uniaxially, dried, cured, and carbonized at 1000 °C. It has been found that polyethylene glycol, which impairs the material properties, can be omitted using sufficient amounts of fructose. The addition of citric acid leads to a further increase in CCS. Consequently, actual optimized environmentally friendly MgO-C batches show a CCS of 85 % of the value of industrial pitch- and resin-bonded bricks without recyclates.CC0 1.0 Universalhttp://creativecommons.org/publicdomain/zero/1.0/4