SR-KS series plastics are developed, using high quality fireclay, bauxite and kyanite group minerals as raw materials, and using chemical and ceramic bondings. Successive mild expansion during heating is their distinctive feature, besides having good work ability, high refractiveness, superior thermal shock and spalling resistance to those of castables. They are suitable for the lining of large-sized heating furnace to give service lives as long as over 10 years.