Abstract

Not being just made of fired mineral ores as conventional products, refractories are increasingly becoming sophisticated with carefully designed compositions and microstructures, for which refractories engineering is of a great necessity. Most past efforts in this aspect are focused on matrix portion. Today, attention has turned to the necessity to engineer aggregates too, as they constitute dominant part in most of refractory products. In this paper, concepts of aggregates engineering were put forwarded and possible engineered structures by purposely designed and controlled shape, surface feature, chemical and phase compositions and their distribution as well as microstructure inside and on aggregate surface were suggested. Some newly developed engineered aggregates, i.e., mullite based hollow balls, mullite based porous spherical aggregates, micro-pored sintered alumina and spherical bauxite and their adoptions in light weight and dense castables were introduced. Exceptional advantages and benefits from using them have been evidenced, highlighted by higher strength, increased flowability, reduced thermal conductivity, enhanced thermal shock resistance and improved size processing effectiveness, compared to conventional counterparts. The direct and potential impacts by using such engineered aggregates on advancement of refractory technology were discussed.