Preparation of high performance blended cements and reclamation of iron concentrate from basic oxygen furnace steel slag

Abstract Basic oxygen furnace steel slag (BOFS) is a by-product of steel-making process that has rarely been utilized in the past and is usually deposited as waste. BOFS fractions with different size were characterized in terms of chemical and mineral compositions, cementitious activity, autoclave soundness and activity index in the present study. The results show that silicates and iron concentrate are inclined to exist in fine and coarse BOFS fractions, respectively. Fine BOFS fractions also present qualified autoclave soundness, high cementitious activity and strength contribution. Iron concentrate, containing about 60% Fe2O3, can be reclaimed from BOFS through a new approach proposed. Blended cements with 30–60% residual slag product have comparable properties with Portland cement. The approach is very helpful to conserve natural resources and energy, achieve cost saving and reduce CO2 emissions.