Dephosphorization kinetics of high-P-containing reduced iron produced from oolitic hematite ore

Abstract

To comprehensively utilize Fe and P in oolitic hematite ore, an innovative method was proposed to enhance P enrichment in the reduced iron during the reduction process. The reduced iron was then converted to low-P-containing molten iron and high-P-containing slag in the presence of CaO–SiO2–FeO–Al2O3 slag. In this study, the P content of the final iron after 0–1,800 s dephosphorization was investigated at different slag composition conditions, and the dephosphorization kinetics of the reduced iron was analyzed. The results showed that the P content of the final iron sample decreased rapidly within 600 s of dephosphorization and became almost constant with increasing dephosphorization time to 1,800 s. The basicity, FeO content, and Al2O3 content also affected the dephosphorization rate of the reduced iron. The apparent dephosphorization rate constant ranged from 1.141 × 10−3 to 2.363 × 10−3 g·(cm2·s)−1, and the overall mass transfer coefficient ranged from 2.47 × 10−3 to 3.38 × 10−3 cm·s−1. The rate-controlling step of the dephosphorization process was the mass transfer of P in both the slag and iron phases. The findings of this study provide a theoretical basis for the utilization of refractory oolitic hematite ore.

Keywords

• reduced iron
• dephosphorization
• apparent dephosphorization rate constant
• mass transfer coefficient