Outline of a Washing Treatment to Improve Electric Arc Furnace Slag Environmental Behavior

Electric arc furnace (EAF) slag is a major byproduct of electric steelmaking with promising reuse potential in various applications. However, environmental concerns related to the leaching of elements such as barium (Ba), chromium (Cr), molybdenum (Mo), and vanadium (V) can hinder its reuse. This study evaluates a water-washing treatment to reduce the leaching of hazardous elements from air-cooled EAF slag produced from carbon, alloyed, and stainless steel grades. Results show that increasing the liquid-to-solid ratio and washing time effectively decreases leachate concentrations. Leaching of Cr, Ba, and Mo increases with decreasing particle size, while V exhibits the opposite trend. A product carbon footprint analysis, based on 1 ton of artificial aggregate, shows a 42.5% reduction in greenhouse gases emissions compared to landfilling when used as a substitute for natural quarry aggregate in concrete production. However, recirculating the wash water into the source water body requires 30 L per heat of 30% HCl to restore pH, representing an operational trade-off.