Theoretical to experimental investigation: A waste utilization technique for iron recovery

Copper slag and tire char are both large-scale industrial solid wastes, which pose a huge threat to the environment if not treated appropriately. Copper slag has 41 wt% iron content, which can meet the growing demand of iron and solve its handling problem. Tire char has 97 wt% fixed carbon thus can be used as a reductant along with CaCO3 and Ca(OH)2 as additives in carbothermal reduction process. Results showed that 0.11 mol of CaCO3 and Ca(OH)2 at 900 degrees C for 60 min give 98.9% and 95.4% iron recovery respectively. Microstructural evaluation of the product demonstrated that fayalite was converted to metallic iron through tire char reductant, along with CO2 from CaCO3 and H2 from Ca(OH)2 also played their parts for the reducing, decomposing, grain growing processes and releasing of iron from complex iron-hosting mineral i.e., fayalite. Aspen plus simulation indicated 0.6 mol ratio of calcium salts recovers 99% Fe at 900 degrees C oven temperature from copper slag which is quite similar to the experimental investigation. By offering a new and environmental friendly approach for detailed investigation of iron recovery from copper slag, this study provides a technical route for handling copper slag waste.