Impact of the reduction of graphite content in critical properties of MgO-C bricks for steelmaking industry

Nowadays, the use of lower amounts of graphite in MgO-C bricks for the steelmaking industry is motivated by several reasons, including the reduction of CO2 emissions. In this work, a MgO-C brick with 12 wt% graphite, was evaluated in comparison with a similar material containing just 8 wt% of this component. The changes induced in the brick by thermal treatments (graphite bed) between 500 and 1400 degrees C were analyzed comparatively. Moreover, the effect of reducing the graphite content in the mechanical properties at RT, 1000 and 1400 degrees C (compressive tests, in argon) and the oxidation resistance in air at 1000 and 1400 degrees C was determined. At 1000 degrees C, the refractory with 8 wt% graphite exhibited the highest mechanical strength and stiffness. Furthermore, although the decarburized area was larger after treatment at 1000 degrees C in air in this brick, the mass and carbon losses showed the opposite trend.