Development of novel spinel refractories for use in coal gasification environments

Work has been performed by Oak Ridge National Laboratory (ORNL), in collaboration with an industrial refractory manufacturer (Minteq International, Inc.), an academic research partner (Missouri University of Science and Technology) and end users to employ novel refractory systems and techniques to reduce energy consumption of refractory lined vessels found in industries such as aluminum, chemical, glass, and pulp and paper. The objective of the project was to address the need for new innovative refractory compositions by developing a family of novel MgO-Al₂O₃ spinel structured unshaped refractory compositions (castables, gunnables, shotcretes, etc) utilizing new aggregate materials, bond systems, protective coatings, and phase formation techniques. As part of the four-year project funded by the U.S. Department of Energy (DOE), materials have been developed specifically for coal gasification environments. Additionally, work has been performed to develop and apply low cost coatings using a colloidal approach for protection against corrosion attack of the refractory brick and to develop a light-weight back-up refractory system to help offset the high thermal conductivity inherent in spinel materials. This paper discusses the development of these materials, along with preliminary results achieved toward the reduction of chemical reactions and mechanical degradation by the service environment.