Article ID: ISIJINT-2025-045
The present study proposes a synergistic reduction method for the efficient recovery of metals from BOF slag and copper slag. This process is accomplished while simultaneously stabilizing secondary slag, thereby achieving the valorization of metallurgical solid waste. The synergistic modification between the two slags has been shown to be conducive to the release of simple iron oxides, including FeO and Fe2O3, from complicated iron-containing mineral phases. This method is regarded as being advantageous for the deep extraction of iron resources. The impacts of mixed slag basicity, reduction temperature and C/O molar ratio on the metal recovery are explored, as well as the synergistic reduction mechanism. The results show that lower mixed slag basicity and higher reduction temperature can promote the metal particle aggregation, which improves the metal recovery rates. Optimum reduction parameters were utilized to yield a ferroalloy containing 95.85% Fe, 3.91% Cu, 0.12% and 0.12% Mn, with a recovery rate of 89.58% for Fe, 96.22% for Cu and 16.85% for Mn. Furthermore, the stable secondary slag contains 0.86% free CaO and 0.79% free MgO, and the hazardous elements from copper slag have been nearly eliminated, resulting in secondary slag that is the stable and non-toxic, and can be used as construction materials. This method enables the comprehensive utilization and valorization of metallurgical solid wastes.
