Effect of flux dispersion behavior on desulfurization of hot metal

Abstract

In order to improve the efficiency of the desulfurization process utilizing the mechanical stirring method, the effect of flux dispersion on the hot metal desulfurization reaction was investigated in 1/8-scale water model and 70 kg-scale hot metal experiments. Flux dispersion behavior is divided into three stages, i.e., "non-dispersion," "transition," and "complete dispersion." The desulfurization rate increases remarkably from the "non-dispersion " to the "complete dispersion" stage, corresponding to the change in the condition of particle dispersion. The relationship between the impeller position and the vortex depth is defined as the dispersion index, I. When the dispersion index was over 1, complete dispersion occurred in water model experiments, and the apparent rate constant increased remarkably in hot metal experiments. The observed diameter of the desulfurization slag was 1.4 mm, which is in good agreement with the calculated value, 1.55 mm. This means that fine desulfurization flux aggregates immediately after the addition of the flux. In order to increase desulfurization efficiency, it is important to control this particle aggregation. © 2010 ISIJ.