Separation and Recovery of Phosphorus from P-bearing Steelmaking Slag

Abstract

In order to recycle the phosphorus from P-bearing steelmaking slag, the influences of magnetic field intensities, slag particle sizes and slag compositions were investigated by magnetic separation experiments. SiO2, Al2O3 and TiO2 melting modification of converter slag was made respectively and phosphorus-rich phase was extracted by magnetic separation. The results show that MgO, MnO, Na2O and CaF2 have little effect on the phosphorus recovery, whereas the addition of SiO2, Al2O3, and TiO2 has great effect on phosphorus enrichment in slag and magnetic separation. With adding the reagent of SiO2, Al2O3 and TiO2, recycled non-magnetic substances are increased obviously and P2O5 content in non-magnetic substances and phosphorus recovery rate are also increased. The phosphorus recovery rates of modified slag No. 8 (SiO2 modification), slag No. 10 (Al2O3 modification) and slag No. 11 (TiO2 modification) are 84. 75%, 82. 16% and 74. 46%, respectively. Then, most of phosphorus was recycled.