Post-smelting FeO reduction and desulfurization

Desulfurization of metal by slag is considered to be controlled by the rate of mass transfer of sulfur in metal. However, one case that has not been examined is the effect of large slag volumes on the rate of desulfurization.; The aim of this thesis was to examine the effect of the level of carbon in molten iron on the rate of FeO reduction, to study simultaneous FeO reduction and desulfurization, and to measure the effect of large slag volumes on the rate of desulfurization. The first two objectives were studied using high temperature experiments and the third was studied using water modeling.; The experiments examining the effect of carbon on the rate of FeO reduction were set up so that FeO was the limiting reactant, and the rate was measured using the constant volume pressure increase technique (CVPI). Experiments were carried out at 1450{dollar}spcirc{dollar}C with 5% FeO in a CaO-SiO{dollar}sb2{dollar}-{dollar}rm Alsb2Osb3{dollar} slag with a CaO/SiO{dollar}sb2{dollar} ratio close to one. Carbon contents were varied between {dollar}sim{dollar}2-4.5 wt. % with sulfur contents ranging from {dollar}sim{dollar}0.003-0.2 wt. %. Carbon content had no effect on the rate of reduction. At high sulfur contents, the rate was believed to be controlled by the rate of the metal/gas reaction and at low sulfur contents the rate was either controlled by liquid phase mass transfer of FeO or by both processes in series.; In the experiments studying simultaneous FeO reduction and desulfurization, the rate of FeO reduction was measured using CVPI and the rate of desulfurization was measured by chemical analysis of the metal. The metal was roughly carbon saturated with 0.2% sulfur and the slag contained 5% FeO. Based on the results, significant desulfurization of the metal by the slag would not be expected until the FeO level was reduced to or below the range of 1-1.5%. The decrease in the FeO content increased the ability of the slag to remove sulfur and also increased the driving force for desulfurization. The rate of transport of sulfur in the metal phase was believed to exert a significant influence on the rate of desulfurization.; In the water modeling work two different modeling systems were used to represent the iron/slag system: water/oil and ZnCl{dollar}sb2{dollar} solution/oil. It was concluded that the ZnCl{dollar}sb2{dollar} solution/oil system more accurately reflected iron/slag behavior than the iron/slag system. The organic compound {dollar}beta{dollar}-naphthol was used to represent sulfur in the ZnCl{dollar}sb2{dollar} solution/oil system and it was found that the rate of mass transfer increased significantly with the oil volume and then leveled off when the oil volume was slightly greater than half the volume of ZnCl{dollar}sb2{dollar} solution. Although it was not possible to predict the upper phase volume at which the rate leveled off, the results indicated that the large volume of slag would enhance the rate of desulfurization. (Abstract shortened by UMI.)...