An Innovative Method for Simultaneous Vanadium Extraction and Dephosphorization from V-Bearing Hot Metal by Calcium Ferrates

The conventional vanadium extraction and dephosphorization processes in the converter are carried out separately, which results in high energy consumption and operational complexity. Calcium ferrates possess the dual function of oxidizing agents and alkaline sources, which provides a novel approach for integrating vanadium extraction and dephosphorization processes. Accordingly, the simultaneous extraction of vanadium and dephosphorization from V-bearing hot metal by the addition of calcium ferrates was proposed in this study for the first time. The experiments were conducted in a low-frequency induction furnace at 1523 K to 1673 K in an inert atmosphere. Thermodynamic calculations and experimental studies demonstrate the potential of calcium ferrates to facilitate vanadium extraction and dephosphorization simultaneously. Especially CaFe 4 O 7 and CaFe 2 O 4 , due to their low melting point and high Oxidizing ability, can reduce the vanadium and phosphorus contents in hot metal to below 0.024 and 0.010 wt pct at 1623 K for 6 minutes of reaction. Correspondingly, the lg L V are 2.42 and 2.37, whereas the lg L P are 2.13 and 2.14, respectively. In the slag, vanadium is oxidized from V 3+ to V 5+ by Fe 2 O 3 with the CaO content increases. A shift from spinel to calcium vanadium silicate is observed. Phosphorus is always present in calcium silicate. The simultaneous vanadium extraction and dephosphorization are achieved only by adding calcium ferrate, effectively recovering vanadium resources and improving semi-steel purity.