Feasibility of Processing Steelmaking Slag for Carbon Dioxide Sequestration and Metal Recovery

The feasibility of processing electric arc furnace (EAF), basic oxygen furnace (BOF) and ladle metallurgy furnace (LMF) slags for metal recovery and carbon dioxide sequestration was evaluated using a combination of grindability and sequestration tests on industrial slags and modeling studies using METSIM. Power consumption, slag-carbon dioxide capture, and metal recovery all increased inversely to grind size (P80) within the range of 50-1,000 μm. The optimum grind size was determined based on a calculated process net value using commodity indexes. EAF and BOF slags exhibited sharp maximum values at 110-120 μm, with a rapid decrease at larger or smaller sizes due to increased power consumption or decreased metal recovery. LMF slag exhibited much less sensitivity to grind size, with ∼3% variation from its peak size of 370 μm over most of the studied range. All slags showed net positive carbon dioxide sequestration benefits based on slag capture and generation by the power supply source.