Dephosphorization in Double Slag Converter Steelmaking Process at Different Temperatures by Industrial Experiments

In the present work, the effect of dephosphorization endpoint temperature on the dephosphorization of hot metal was studied for the double slag converter steelmaking process under the conditions of low temperature and low basicity by the industrial experiments. In the temperature range of 1350-1450 degrees C, with an increasing dephosphorization endpoint temperature, the dephosphorization ratio and phosphorus distribution ratio first increase and then decrease. The phosphorus content in hot metal first decreases and then increases at the end of dephosphorization. At the dephosphorization temperature range of 1385-1410 degrees C, the dephosphorization ratio is higher than 55%, the P2O5 content in the dephosphorization slag is 3.93-4.17%, the logL(P) value is 1.76-2.09, the value of P-CO(P-C) of the selective oxidation reaction of carbon and phosphorus is 53-80 Pa, and the a(FeO) value is 0.284-0.312. The path of phosphorus in hot metal entering the P-rich phase of dephosphorization slag can be reasonably inferred as: hot metal -> Fe-rich phase -> P-rich phase. Under the present industrial experimental conditions, the dephosphorization and rephosphorization reactions are in dynamic equilibrium at 1413 degrees C. Considering the experimental results and thermodynamic calculation results of industrial experiments by the double slag dephosphorization process, the optimal temperature range for intermediate deslagging is about 1400-1420 degrees C.