Hydrogen preserves microstructure to enhance steelmaking dust recycling

Electric arc furnace dust a hazardous waste from galvanized steel recycling, presents a significant challenge to sustainable steel production. Here, we show that hydrogen reduction, under industrially relevant conditions, offers a transformative solution for dust valorization. Compared to conventional carbothermic reduction, hydrogen achieved higher zinc recovery (98.8-99.7% vs. 86.2-90.0%), enhanced iron metallization, and superior removal of sulfur and phosphorus. This is attributed to hydrogen’s enhanced diffusivity and reactivity, which prevents the microstructural degradation (pore closure) that limits carbothermic reduction. Importantly, we demonstrate the feasibility of selective zinc extraction, allowing dust recycling even without simultaneous iron reduction. This work provides a pathway for transforming dust from a hazardous waste into valuable resources, contributing to a lower-carbon and more resource-efficient steel production process.