HISTORYRefractories have been used by humankind since earliest history. When humans first began to smelt metals and shape primitive knives, hunting weapons, and ornamental rings and jewelry, crude refractory materials were developed to facilitate the pyroprocessing of the ores. As refractory practice developed, materials evolved which were ever more durable, lasting longer and longer before replacement was necessary. DEFINITIONRefractory materials are materials, which have th...