Modification of Copper Slag Composite with Water-Quenched Silicon-Manganese Slag

Metallurgical industries often discharge slag containing valuable elements that are poorly utilized when producing copper alloys and silicon-manganese alloys. To improve the utilization rate, in this study, a method to mix copper slag with water-quenched silicon-manganese slag and CaO for roasting and modification was proposed. In this work, FactSage 8.0, DSC-TG, and XRD were used to examine the phase change during the modification process and investigate the impacts of the CaO content, roasting temperature, and holding time on the modification effect. The results showed that the addition of water-quenched silicon-manganese slag and CaO could effectively promote the transformation of fayalite to (Mn, Mg, Fe)Fe₂O₄, with the highest conversion rate occurring at a 10% CaO content. An increase in the temperature and prolongation of the time facilitated fayalite transformation, but excessive temperature or time could result in iron loss. The optimal recovery rate and iron grade were achieved with roasting at 1400 °C for 60 min. This method can provide a concentrate suitable for producing copper-containing antibacterial stainless steel and wear-resistant cast iron, and the tailings can be used to produce ceramic materials.