Effect of highly oxidizing converter dephosphorization slag on dephosphorization behaviour of molten steel

ABSTRACT In order to study the effect of highly oxidizing dephosphorizing converter slag on the migration behaviour of phosphorus in molten steel, an industrial test was carried out on a 300t dephosphorizing converter in a steel plant by the duplex method. Theoretical analysis shows that when the temperature is low, the basicity is 1.5 and the FeO content is 25%–30%, the phosphorus capacity of slag is stable. The industrial test results show that when the temperature is 1630K–1665K, the basicity is 1.05–1.25, the FeO content is 35%–40%, and the dephosphorization efficiency of the converter can generally reach above 60%. XRD and SEM-EDS analysis results showed that phosphorus was mainly enriched in 2CaO·SiO2-3CaO·P2O5 solid solution. Infrared analysis results show that under the condition of high FeO and low basicity, properly increasing of basicity is beneficial to reduce the degree of polymerization of dephosphorization slag.