Breaking boundaries in slag waste heat recovery: Review and future perspective of dry centrifugal granulation technology

Climate change posed the greatest threat to human sustainable development, and reducing carbon emissions was a pressing issue for all humanity. Among the most energy-intensive and carbon emissions industries, the iron and steel industry (ISI) represented almost 5 % of energy consumption and 7 % carbon emissions around the world. The ISI faced severe challenges from the “relative constraints” of carbon emissions intensity to the “absolute constrains” of total carbon emissions. Waste heat played an indispensable role in the low-carbon development of ISI. The heat contained in the blast furnace slag (BFS) was considerable, and it was an important position to be occupied. In recent decades, the proposal and development of dry centrifugal granulation (DCG) technology had provided researchers with great encouragement and brought the dawn to overcome the problem of slag waste heat recovery. This technology had been hailed as one of the most suitable technologies to boost sustainable transition of the ISI. This paper provided a detailed review of DCG technology including granulation characteristics of BFS, flight and impingement behavior of slag particles, slag transformation in granulation chamber, waste heat recovery process, etc. Furthermore, the implementation and technical characteristics of semi- and industrialization implementation for DCG technology were explored and elaborated as comprehensively as possible. Ultimately, the problems existing in the development of this technology were analyzed, and suggested the future direction and challenges. This paper aiming to pave the way for the waste heat recovery of BFS while supporting the market penetration and enhancing the role in the fight against climate change for ISI.