Phosphorus equilibrium between BaO‐BaF₂‐MnO fluxes and ferro‐manganese melts

Abstract

The equilibrium distribution ratio of phosphorus between BaO-BaF 2-MnO slags and Mn(62-73%)-Fe-C sat-P melts has been determined for different slag compositions, oxygen partial pressures and at 1573-1673 K. The results showed that with a certain content of BaO in the slags, the phosphorus distribution ratio increased with increasing oxygen partial pressure up to about 10-17 atm. A high oxygen partial pressure resulted in a substantial oxidation of manganese from metal to slag. The phosphate capacity of BaO-BaF 2-MnO slags increased with the BaO content and decreased with the MnO content in the investigated slag composition range. A high temperature resulted in a low phosphorus distribution ratio. For a BaO(50%)-BaF 2(47%)-MnO(3%) slag, the effect of temperature on the phosphate capacity in the range of 1573-1673 K could be expressed as:The heat of reaction:was estimated to be -1107 kJ/mole. Phosphorgleichgewicht zwischen BaQ-BaF2-MnQ-FluBmltteln und Ferromanganschmelzen. Das Gleichgewichtsverteilungsverhaltnis von Phosphor zwischen BaO-BaF 2-MnO-Schlacken und Mn(62-73%)-Fe-C ges-P-Schmelzen wurde fOr verschiedene Schlackenzusammensetzungen und SauerstoffpartialdrOcke im Temperaturbereich 1573-1673 K bestimmt. Die Ergebnisse zeigen, daB das Phospho rverteliunqsverhaitnls bei einem bestimmten BaO-Gehalt in der Schlacke mit dem Sauerstoffpartialdruck (bis ca. 10-17 atrn) ansteigt. Ein hoher Sauerstoffpartialdruck schlagt slch in einer substantiellen Mn-Oxidation vorn Metall zur Schlacke nieder. Die Phosphatkapazitat der BaO-BaF 2-MnO-Schlacken wachst mit dem BaO-Gehalt, tallt jedoch mit dem MnO-Gehalt im Zusammensetzungsbereich der untersuchten Schlacken. Hohe Temperaturen fOhren zu einem geringen Phosphorverteilunqsverhaltnis. FOr eine BaO(50%)-BaF 2(47%)-MnO(3%)-Schlacke kann der TemperatureinfluB auf die Phosphatkapazitat im Bereich 1573-1673 K durch die Gleichung: 5.85.10 4 10gCpo~-= T -9.25ausgedrOckt werden. Die Heaktionswarrne der Umsetzung 1/2P 2 (g) + 5/40 2 (g) + 3/2(BaO) = Ba1.SP04 betraqt -1107 kJ/mol.

Dephosphorization of ferromanganese using BaCO3-based fluxes by submerged injection of powders: A preliminary kinetic study

“…Some recent studies [1,2] have established the ancy and breaks into bubbles due to the hydrostatic head, feasibility of dephosphorization of high carbon ferromangasurface tension, and drag forces. The and transitory contact reactions for the present dephosphorihigh phosphorus content (0.35 to 0.50 pct) of high carbon zation study, which might subsequently help in selecting the ferromanganese originates from the manganese ores, the design parameters that could be of importance for efficient majority of which contain a significant amount (ϳ0.2 pct) phosphorus removal.…”

“…Some recent studies [1,2] have established the ancy and breaks into bubbles due to the hydrostatic head, feasibility of dephosphorization of high carbon ferromangasurface tension, and drag forces. However, an increase in permanent contact reaction, at a…”

Investigation into the dephosphorization of ferromanganese alloys for the production of advanced high-strength steel

“…This anomaly may be attributed to the analytical errors for samples from either the 1400°C or 1450°C experiments. Liu et al (1995) similarly observed lower L p values as the temperature was increased during dephosphorization of FeMn alloy with BaO-containing slags.…”

“…Factors that may have contributed to the loss of Mn include possible air ingress during the tests and the exposure of the alloys to oxygen during quenching, as Mn has a high affinity for oxygen. Liu et al (1995) observed that the use of CaO, SiO 2 , and CaF 2 to dephosphorize ferromanganese melts resulted in increased Mn losses to the slag. Watanabe et al (1993) reported that MnO in basic slag acts as a diluent which may lessen the basic effect of the slag, reducing the capacity of the slag to remove P from the alloy.…”

“…High amounts of MnO may affect the activity of the basic oxides such as CaO and BaO in the slag and can reduce the capacity of the slag to absorb P. Chaudhary, Minj, and Goel (2007) observed that an increase in the MnO content to above 20% (in BaOcontaining slag) resulted in poor P removal. In the HCFeMn dephosphorization studies by Liu et al (1995), it was observed that an increased concentration of MnO in slag had a negative influence on the phosphate capacity of BaO-MnO-BaCl 2 slag. It was, therefore concluded from the investigations that an MnO content above a certain value is detrimental to the capability of the slag to dephosphorize FeMn alloys.…”