Liquidus relations of ferromanganese slags

Backgrounds/aims: The purpose of this investigation was to determine liquid us compositions for ferromanganese slags. Methods: Measurements were carried out in a graphite resistance furnace at 1450 degrees C, 1500 degrees C and 1550 degrees C in an argon atmosphere. M olybdenum crucibles were charged with small amounts of slag. Samples were h eld at temperature for 1.5 h and then quenched in a water bath. Liquidus co mpositions were determined by analysing the quenched glass in each sample u sing an electron microprobe. Results and conclusions: Liquidus composition lines are presented at 1450 d egrees C, 1500 degrees C and 1550 degrees C for the slag system MnO-SiO2-Al 2O3-CaO. An increase was observed in the content of MnO at liquidus with in creasing basicity ratios, CaO/(SiO2+Al2O3). The Al2O3/SiO2 ratio had little effect on the liquidus content of MnO for slags with basicity ratios of 1/ 3, 2/3 and 1 at 1450 degrees C, 1500 degrees C, and 1550 degrees C. The add ition of MgO changes the liquidus composition in the direction of the acidi c oxide apex, thereby reducing the size of the liquid region. This effect i s more pronounced at higher basicities and at higher temperatures. The MgO/ CaO ratio has little effect on the liquidus composition.