A novel approach for recovery of iron from copper slag using calcium salts

Copper slag is not only a waste but it has many valuable and recoverable metals present in it such as iron. Therefore, this study focuses on the utilization of waste materials i.e., copper slag and tire char for iron recovery. Four calcium salts, i.e., CaCO₃, Ca(OH)₂, CaCl₂, and CaSO₄, with different dosages, reduction temperature, reduction time, and atmospheric conditions were investigated in order to find best reaction mechanism for iron recovery. Among these salts, the optimum conditions were determined: using CaCO₃ under 0.384 of CaO/SiO₂ molar ratio in a 60-min reduction period at 1473.15K temperature, that gives 91.14% iron recovery. Both FESEM-EDS data and chemical titration showed more than 70% of the highest iron grade in the recovered product. The analysis results indicate that main impurity in the whole procedure was carbon from coal char that reduces the iron grade. This research not only provides a novel way to recover iron from copper slag, but also provides a future direction to handle copper slag and tire char waste materials.