Kinetics of Flux Dissolution in Oxygen Steelmaking

Abstract

Based on the previous studies, when lime dissolves in silica containing slag, a film of dicalcium silicate, 1474© 2009 ISIJ ISIJ International, Vol. 49 (2009), No. 10, pp. 1474-1482 Kinetics of Flux Dissolution in Oxygen SteelmakingNeslihan DOGAN, Geoffrey A. BROOKS and Muhammad Akbar RHAMDHANI A mathematical model has been developed to predict the dissolution rate of added fluxes such as lime and dolomite as a sub-model of an overall kinetic model of top-blown oxygen steelmaking process. The calculation of dissolution rates included dimensionless analysis technique as well as the evolution of gas generated due to decarburization reaction during the blowing process. The progress of flux dissolution and the amount of slag generated were predicted as a function of saturation concentration of CaO and MgO in the slag, CO gas flow rate and the physical properties of slag throughout the blow. The results from the model were consistent with the plant data from the study of Cicutti et al. The influences of variations in solid particle size and flux addition rate on flux dissolution were also investigated. It has been shown in this study that the amount of flux dissolved in oxygen steelmaking process is accelerated if the addition rate of flux is increased or if the size of flux particle is decreased.

Influence of Magnesium Oxide Content on Kinetics of Lime Dissolution in Steelmaking Slags

“…4) The observed drop in the equilibrium concentration of CaO in the slag samples with the increasing content of MgO in lime can be explained by an increase in (Mg, Fe and Ca) silicates and magnesiowustite concentration in the volume of lime, which as a consequence, further complicates the process of lime dissolution. 4,8,15,17) Figure 8 shows microscopic raster images (SEM Tesla XRAY Oxford) of lime containing 4.3, 7.6 and 80% MgO, after 5 minutes of immersion in the melt at 1 500°C, and the phase composition of samples carried out with a powder diffractometer "Bruker D2 Phaser". Sample containing 80% of magnesium oxide was prepared by Voestalpine Stahl Linz consisting of periclase (MgO) and portlandite (Ca(OH) 2 ) phases.…”

“…The increase in the concentration of MgO in lime slows down the dissolution rate of the samples. In the work 4,15) authors measured the rate of calcined dolomite samples СаСО 3 ·MgCO 3 dissolution in the slag with the composition FexO-CaO-SiO 2 , containing FeO from 20 to 65%. Authors suggested a limitation of the MgO diffusion in the slag containing FeO more than 20% through the surface layer at the interface.…”

“…Elizaveta CHEREMISINA, 1) * Johannes SCHENK, 1) Ludwig NOCKE, 2) Alexander PAUL 3) and Gerald WIMMER 4) 1) Department of Metallurgy, Montanuniversität Leoben, 8700 Austria.…”

Dissolution Behavior of Lime into Steelmaking Slag

“…Over these ten years, a lot of research has been conducted with dynamic tests, [26][27][28][29]32) stagnant tests, [33][34][35] theoretical modelling, 36) and process simulation to consider the slagging behavior. 37,38) This indicates that the dissolution of lime is still one of the unsolved subjects in steelmaking reactions.…”

Comprehensive Model of Oxygen Steelmaking Part 2: Application of Bloated Droplet Theory for Decarburization in Emulsion Zone

“…The calculation procedure of physical properties of slag was provided in the previous publication. 34) Droplet generation was then calculated as a function of blowing conditions as explained elsewhere. 35) The output results of droplet generation submodel were used to calculate the initial velocity of metal droplets ejected to the emulsion phase and to calculate the quantity of metal droplets ejected.…”