Recovery of Manganese and Phosphorus from Dephosphorization Slag with Wet Magnetic Separation

The dephosphorization slag has a great potential as the secondary resources of manganese and phosphorus, while quite a large amount of slag is landfilled and simply reused such as cement. The objective of this study is to investigate the recovery of manganese and phosphorus by wet magnetic separation technique. The hot metal pretreatment slag (dephosphorization slag) generally contains a Ca3P2O8-Ca2SiO4 (phosphorus enriched phase) and FeO-MnO (manganese enriched phase) solid solutions together with FeO-CaO-SiO2 matrix phase. Since the difference in their magnetic properties is significant, it is possible to separate each phase with the aid of wet magnetic separation. By applying strong magnetic field to the crushed slag (<32μm), 31% of phosphorus enriched slag and 14% manganese enriched slag could be successfully recovered.