Optimization of magnetic separation process for iron recovery from steel slag

To improve the efficiency of iron recovery from steel slag and reduce the wear-and-tear on facilities, a new method was proposed by adding a secondary screen sizer to the magnetic separation process according to grain size distribution of magnetic iron (M-Fe) in the slag. The final recycling efficiency was evaluated by calculating the percentage of recycled M-Fe to the maximum amount of M-Fe that could be recovered. Three types of slags, namely basic oxygen furnace slag, desulfurization slag, and iron ladle slag, were studied, and the results showed that the optimized recovery efficiencies were 93. 20%, 92. 48%, and 85. 82% respectively, and the recycling efficiencies were improved by 9. 58%, 7. 11%, and 6. 21% respectively. Furthermore, the abrasion between the mill equipment and the remaining slags was significantly reduced owing to the efficient recovery of larger M-Fe particles. In addition, the using amount of grinding balls was reduced by 0. 46 kg when every 1 t steel slag was processed.