Enhancing Recycling Potential: Exploring Reduction and Metal Separation Behavior of Iron-Rich Slag in Electric Arc Furnace Smelting for a Sustainable Future

Abstract

The electric arc furnace steelmaking route is essential for sustainable steelmaking through hydrogen-based direct reduced iron. About 30% of the global steel production currently follows the scrap/direct reduced iron-electric arc furnace (DRI-EAF) route, which is bound to increase given decarburization efforts by the steel industry. We investigated DRI-EAF slag recycling simulated in laboratory EAF smelting tests to lower its environmental impact. Several aspects of process development were explored, such as process conditions, specific energy consumption, and the settling behavior of iron particles. Significant reductions occur in the first 15 min, ranging from 73.4% to 83.34%. About 97% iron was recovered under optimum conditions: basicity-1.2, carbon/oxygen ratio-1, and time-40 min. The settling velocities of iron particles decreased with increasing slag basicity, reaching values of 3.13 x 10-5 m/s, 1.95 x 10-5 m/s, and 0.89 x 10-5 m/s for basicities 0.9, 1.2, and 1.5, respectively. The effects of basicity on slag viscosity, phase formation, and energy consumption are critically discussed. Compared to 0.9, basicities of 1.2 and 1.5 increase power consumption by 17.6% and 23.5%, respectively. The findings potentially contribute to managing DRI-EAF-based slag, repositioning it as a potential resource, and reducing associated pollution.