Effect of P2O5 on the Melt Structure and Transport Property of Slag from the Double Slag Steelmaking Process

The continuous enrichment of phosphorus in the double slag steelmaking process affects the structure and properties of steelmaking slag. In this study, the effect of P 2 O 5 on the structure and transport property of CaO-SiO 2 -P 2 O 5 -FeO melts was investigated by molecular dynamics calculation. The results indicate that, with the increase of P 2 O 5 content, the Ca-O bond length increased and the Fe-O bond length decreased, the Si-O and P-O bond lengths fluctuated around 1.61 Å and 1.54 Å, respectively, and the [SiO4] 4- and [PO4] 3- tetrahedral structures exhibited stability. The proportions of FO and BO decreased from 25.10% and 23.10% to 13.70% and 19.60%, respectively, while the proportion of non-bridging oxygen increased from 51.90% to 66.70%, and the aggregation degree of the system showed a decrease tendency. As the P 2 O 5 content increased, the self-diffusion coefficient of Fe 2+ ions increased significantly from 7 × 10 −6 Å 2 /ps to 1.42 × 10 −4 Å 2 /ps, P 5+ , O 2− , and Ca 2+ ions also showed an increasing trend, whereas Si 4+ showed no significant change. Concurrently, the structural aggregation of the system decreased.