Lower Consumptions by Lightening Refractories
Two major concepts are put forwarded, i.e. lightened aggregates and high performance lightweight (LW) castables. The related R & D work and practices are introduced. LW castables are of important part of monolithic refractories, and their high performance is necessary to full play the role in energy saving and material consumption reduction. Concepts for achieving high performance are put forwarded, summarized as “4-highs and 2-lows”, i.e. high purity, high strength, high service temperature, high resistance to furnace atmosphere attack, low thermal conductivity and low shrinkage at service temperature. Different approaches to such targets are suggested. Adopting such approaches and using suitable starting materials, LW aggregates in Al2O3–SiO2, MgO–SiO2 and Al2O3–CaO–MgO systems were developed, featured by hollow ball or micropored structure. They were used as aggregates to make different LW castables. The developed LW Al2O3–SiO2 castables have been adopted as steel ladle back lining, water cooled skid and post lining of reheating furnace and back lining of tin bath hearth in glass industry, all with encouraging results. Laboratory work and in-plant trails indicate that the suggested concepts and approaches are effective.