Study of the Thermal Behavior of Organic Binders Used in Oxide-Carbon Refractory Bricks

Organic substances are used in refractory bricks manufacture as binders. In this work, two commercial binder systems currently employed in MgO-C bricks for steelmaking industry were first analyzed separately from the other components of the refractory. A resol phenolic resin alone and mixed with an ecobinder produced by treatment of tar pitch were studied by several techniques (XRD, FTIR, Raman spectroscopy, DTA/TGA and measurements of density, porosity, and mechanical and oxidation resistances) in their as-received condition, as well as after thermal treatments in conditions near to those used in the manufacture of the bricks (temperatures lower than 300 °C) and also during their service (in the range 600 °C to 1400 °C). The comparative analysis of the obtained results indicates that the ecobinder has domains of ordered carbon in its original condition, although the resin forms a stronger three-dimensional structure after treatments at low temperature (< 300 °C). When both binders are mixed and temperature rises from 600 °C onwards, experimental data show that they evolve with no or little interaction; the produced carbon has more and larger crystalline regions when the ecobinder is present. Finally, the effect of the binders’ characteristics on some properties of MgO-C bricks which have them incorporated were briefly analyzed.