A Review of Circular Economy Prospects for Stainless Steelmaking Slags

The production of stainless steel reached 52 Mt in 2019, with an estimated annual slag generation of 15–17 Mt from various processes including electric furnaces and AOD converters. Despite their potential, only a small fraction of these slags are recycled, while the majority are disposed of in landfills, which poses environmental concerns due to the presence of high-value elements such as Cr, Ni, Mo, Ti, and V. This review investigates the characteristics of stainless steelmaking slags and explores innovative methods aimed at enhancing internal recycling and modifying slag properties for high-value applications. The study discusses techniques such as fast controlled cooling and the use of modifying additives to improve slag composition. Additionally, it examines recovery methods for valuable metals and outlines potential applications for different slag types based on their unique chemical, physical, and mechanical properties. By integrating the management of slag treatments within a comprehensive process optimization framework, the principles of a circular economy can be effectively realized, leading to significant economic and environmental benefits.