Research status of centrifugal granulation, physical heat recovery and resource utilization of blast furnace slags

Abstract

Abstract The molten blast furnace slags, a kind of main by-product in Iron and Steel industry, contains a substantial amount of high-grade thermal energy and untapped resources, and thus their heat recovery and resource utilization are essential to industrial energy saving and emission reduction. The traditional water quenching waste heat recovery method is expected to be replaced by dry post-processing technologies due to the water conservation and efficiency issues. A typical process of centrifugal granulation - physical heat recovery - resource utilization with the advantages of simple structure and a large waste heat recovery potential is focused in this review. The mechanism, phenomenon, influence factors of centrifugal granulation process from analytical, experimental and numerical simulation sides are discussed. The developed correlations of liquid film thickness, ligament number, droplet diameter are summarized. Physical waste heat recovery process after centrifugal granulation through a fluidized bed or moving bed is always accompanied with the solidification and phase evolution of the slag particles, which exert a significant influence to their further utilization. The development of different physical heat recovery methods and investigations on phase evolution during the cooling process are presented, and the further utilizations of slag particles as substitutions of cement, ceramics, composite phase change materials are summarized.