The effects of binder type combined with graphite content and the presence of aluminum on the characteristics of MgO-C bricks

In this paper, a systematic study regarding the combined effects of critical variations in MgO-C brick compositions, such as the graphite content (varied in 8 and 12 wt%) and the presence of aluminium (2 wt%), are analysed together with the use of a solid soft-binder (or ecobinder) mixed with a liquid phenolic resin. The bricks have controlled compositions and were manufactured in-plant using the current procedure for commercialproduct bricks; the obtained results are compared with those from bricks with the same composition but bonded with the resin alone. The presence of aluminium produces opposite effects in the physical characteristics, such as the bricks' particle size distribution and pore volume when the mixed system or just the resin is employed as the binder. As expected, the resin-based bricks possess greater stiffness and mechanical strength (at RT) than those bonded with the addition of the soft-binder. However, contrary to our expectations, the presence of the soft-binder does not improve oxidation resistance at 1400 degrees C. On the other hand, the impact of the graphite content on the mechanical behaviour (at RT) is higher than the presence of aluminium for any of the binder type (resin alone or mixed with the ecobinder), but the contrary is observed for the brick's oxidation resistance.