Decarburization of high carbon ferromanganese melts

Abstract

The effect of oxygen/argon mixing ratio in the bottom blowing gas on the decarburization behaviour of high carbon ferromanganese melt was investigated in the temperature range of 1350 -1550°C. Thermodynamic analysis indicates that high melt temperature and low Pea are essential for an effective decarburization. An empirical equation for the utilization ratio of oxygen for decarburization was derived as functions of the melt temperature and the oxygen/argon mixing ratio in the refining gas. The utilization ratio of oxygen for decarburization sharply increases as the melt temperature increases and the oxygen ratio in blowing gas decreases. In oxygen refining of high carbon ferromanganese melt, it is not desirable to inject oxygen through bottom tuysres in an early stage of refining. When the melt temperature is low, the oxygen predominantly oxidizes the manganese in melt in spite of high carbon contents. The injection of oxygen/argon mixture gas is found to be an effective decarburization technique when the melt temperature is higher than 1500°C. Cas Entkohlungsverhalten von hochkohlenstoffhaltigenFerromanganschmelzen. Der EinfluB des Oz/Ar-Mischunqsverhaltnisses im Ruhrqas beim Bodenblasen auf das Entkohlungsverhalten einer hochkohlenstoffhaltigen Ferromanganschmelze wurde im Temperaturbereich 1350 -1550°C untersucht. Die thermodynamische Analyse zeigt, daB eine hohe Temperatur und ein niedriger Pea grundlegend fur eine wirksame Entkohlung mit Sauerstoff sind. In Abhiingigkeit von der Temperatur und dem O/2Ar-Mischungsverhiiltnis wurde eine empirische Gleichung, die den Sauerstoffnutzungsgrad fur die Entkohlung beschreibt, hergeleitet. Der Sauerstoffnutzungsgrad nimmt mit zunehmender Temperatur und abnehmendem 02/Ar-Verhaltnis deutlich zu. 1m ersten Blasabschnitt des Frischprozesses ist das Bodenblasen mit Sauerstoff im Faile hochkohlenstoffhaltiger Ferromanganschmelzen nicht erwunscht. Obwohl der Kohlenstoffgehalt hoch ist, oxidiert Mangan bei niedriger Badtemperatur bevorzugt in der Schmelze. Das Einblasen eines Oz/Ar-Gasqernisches in die Schmelze erweist sich als gunstig, sobald die Badtemperatur auf uber 1500°C ansteigt.

Nitrogen solubility in liquid manganese and ferromanganese alloys

“…They determined Therefore, the equilibrium nitrogen solubility in a pure the standard free energy of nitrogen dissolution as ⌬GЊ T ϭ manganese melt as a function of nitrogen partial pressure can be calculated at any temperature using Eqs. [5], [7], and Ϫ57,656 ϩ 27.8T J/g atom by taking the molten manganese in equilibrium with a nitrogen pressure of 101.33 kPa as the [9]. The solubility calculated at 1823 K is plotted as a solid line together with the experimental data obtained by various authors, for comparison, in Figure 9.…”

“…derived in this work can be used to determine the activity Gocken [7] measured the nitrogen solubility in a manganese coefficient of nitrogen at various nitrogen contents in a manmelt at 1546 to 1773 K by bubbling pure nitrogen gas for ganese melt, using Eqs. [5] and [7]. Figure 8 shows the 1 hour into the melt in an alumina crucible placed in a variation of f N calculated as a function of nitrogen content tubular furnace.…”

“…Therefore, from Eqs. [5] and [6], the standard Gibbs freeenergy change for the dissolution of 1 g atom of nitrogen in liquid manganese can be derived as…”

“…of low-carbon ferromanganese alloys. [1][2][3][4][5] In this process, Pure liquid metals of very high nitrogen solubility, such as the oxygen-inert gas mixture is injected so that carbon is niobium, exhibit a large deviation from Sievert's law, [17] oxidized in preference to manganese, because CO is diluted probably due to the interaction between nitrogen atoms in with inert gases such as argon and nitrogen. Nitrogen is the melt.…”

Nitriding of Medium Carbon Ferromanganese Alloy in Gas Solid Reaction

“…This fine size alloy must be retreated to be suitable for utilization. Due to the increased demand for nitrogen to replace nickel it is suggested to produce high nitrogen ferromanganese through nitrogenation-in solid state-of these fines [1][2][3][4][5][6].…”