Mesophase pitch and phenolic resin blends as binders for magnesia-graphited bricks

Naphthalene-derived mesophase pitch (NMP) and phenolic resins of novolac ty pe and resol type were applied for the binder of MgO-C brick. NMP provided a brick of high strength at over 1000 degrees C and high oxidative resistiv ity, however, the apparent porosity of the brick was high because of NMP's expansion at the carbonization. Both types of resins provided bricks of hig h strength and low apparent porosity at low temperature, the strength serio usly decreasing over 1000 degrees C, A blend of NMP and the resins provided bricks of excellent performance with high strength and low apparent porosi ty in a wide temperature range and high oxidative resistivity. The thermose tting resin bound MgO around 100 degrees C and surrounded the dispersed NMP particles to prevent expansion at the latter carbonization, while NMP-orig inating carbon moderated the strong shrinkage of the resin over 1000 degree s C, maintaining the high strength and density of the brick in a wide tempe rature range. (C) 1999 Elsevier Science Ltd. All rights reserved.