Potential Waste Heat Recovery Analysis From Molten Steel Slag: The Case Study of Sidenor Steelworks in Basauri (Spain)

Every day, a huge amount of energy is released into the atmosphere in the form of waste heat. The search for a cleaner and more efficient society, not only at the industrial level but also at the domestic level, should avoid this type of emissions. Steelmaking is an example of an industrial sector with high optimization potential in energy management. In this line, this work presents the main outcomes of the investigation carried out in the search of a technical solution for heat capture and reutilization from one of the main waste heat streams in the steelworks, the molten slag. For this purpose, a piping system embedded in the slag pit soil is proposed as a satisfactory solution for the heat capture operation. Besides, the internal applicability of this recovered heat is also addressed. Overall, the analysis carried out allows the identification of the maximum energy that can be recovered from the slag if the proposed technology is implemented (around 306 kWh_t per casting, which represents 6.3% of the total available energy). The work is completed with a preliminary techno-economic analysis which has shown a depreciated payback period of the proposed technology below 7 years.