Exploiting the Molten Slag to Decarbonize Iron and Steel Industry: Feasibility Analysis of Centrifugal Granulation-Assisted Thermal Energy Recovery System beyond Pilot Scale

Waste heat recovery from molten blast furnace slag at approximate to 1500 degrees C represents new opportunities for slag valorization. This is now gaining the spotlight but still remains a grand challenge in the iron and steel industry (ISI). To address this issue, centrifugal granulation-assisted thermal energy recovery (CGATER) is proposed and is regarded as the leading slag treatment technology. The CGATER provides a viable alternative to exploiting the waste heat in molten slag. Yet, large-scale implementation of CGATER is little explored beyond laboratory-scale tests. The fate of CGATER toward future commercialization is rarely considered and analyzed, either qualitatively or quantitatively. This work intends to provide, for the first time, a paradigm of a commercial-scale CGATER prototype, which allows for slag treatment with a rated throughput of 36 t-slag h(-1). The feasibility of commercial-scale CGATER with a comprehensive scrutinization of its energy, resource, and environment flows is analyzed. The CGATER prototype demonstrates attractive attributes of 1) being nearly water free and 2) suppressing sulfur-related emissions, although with higher energy consumption than the water quenching method. This work provides not only an inclusive figure of CGATER design but also sheds light on the feasibility of CGATER commercialization to decarbonize ISI.