A physical model based on similarity principles was built to simulate RH desulfurization process. In order to quantitatively analyze RH desulfurization process, a mathematical model was proposed. By analyzing experimental results with the mathematical model, an empirical formula whose determination coefficient was 0.98 was given to express the relationship between transient desulfurization efficiency and time. All the determination coefficients of four fitted curves based on four repeated experiments with different gas flow rates were more than 0.94, which was the exact evidence of the rationality of the empirical formula. Meanwhile, it was found that transient desulfurization ability increased firstly and then decreased with increasing gas flow rate and reached the maximum value when the gas flow rate was 1.8 m^3/h. A plenty of repeated trials showed the same rule, which validated the mathematical model and the conclusions obtained from physical experiments.
To clarify the influence of Fe O and sulfur on solid state reaction between an Fe-Mn-Si alloy and Mn O-Si O2-Fe O oxides under the restricted oxygen diffusion flux, two diffusion couples with different sulfur contents in the oxides were produced and investigated after heat treatment at 1473 K. The experimental results were also compared with previous work in which the oxides contained higher Fe O. It was found that although the Fe O content in the oxides decreased from 3wt% to 1wt% which was lower than the content corresponding to the equilibrium with molten steel at 1873 K, excess oxygen still diffused from the oxides to solid steel during heat treatment at 1473 K and formed oxide particles. In addition, increasing the sulfur content in the oxides was observed to suppress the diffusion of oxygen between the alloy and the oxides.
