Valorization pathways and emerging applications of steel slag in China: A review

Steel slag (SS) is a primary by-product of steelmaking. It is accumulating rapidly in China with an annual output exceeding 150 million tons, yet its utilization rate remains below 30%. The substantial accumulation of SS poses significant environmental issues. Therefore, improving the reutilization rate of SS is essential for resource efficiency and environmental conservation. Conventional applications such as metal recovery, cement manufacturing, and road construction contribute to SS consumption but have low-added value, providing limited economic benefits. Furthermore, the newly enacted GB175-2023 standard explicitly prohibits the use of SS as a blended material in common Portland cement, further limiting its utilization. Recent advancements in the uses of SS in carbon capture, environmental remediation, functional materials and 3D printing have demonstrated significant potential. This review systematically evaluates the valorization pathways of SS based on its physicochemical properties, covering both conventional large-scale utilization and emerging high-value applications, clarifying the correlations among SS composition, responsiveness, and performance across various application paths, and highlighting key challenges, potential solutions, and future development directions toward sustainable and low-carbon deployment.