Effect of reductive component-conditioning materials on the composition, structure, and properties of reconstructed BOF slag

•The reduction rate of Fe2O3 in BOF slag at high temperature using bituminous coal exceeds 95%.•The cementitious activity of the reconstructed BOF slag is improved significantly.•A significant correlation exists between the reduction degree of reconstructed BOF slag and its cementitious activity.•The mineral composition of the reconstructed BOF slag becomes closer to the Portland cement clinker.