Tracking Inclusions during Ladle Refining Using a Kinetic Model for the Compositions of Metal, Slag, and Inclusions

Abstract

A mathematical kinetic model to predict the trajectory of chemical compositions of the molten steel, slag, and inclusions in the ladle metallurgy furnace was presented in a recent study. The model considered the following chemical processes: 1) the rate of slag–steel reaction; 2) the rate of supply of calcium during calcium treatment; and 3) the rate of steel–inclusion reactions, including oxides and sulfides. Herein, the model is further validated by running the model in varying conditions and comparing the predicted and measured composition of inclusions and dissolved species in the steel for additional plant heats. A sensitivity analysis is also carried out to investigate the effect of different parameters, including sulfur content of steel, total oxygen, slag composition, and reoxidation of steel on the trajectory of composition of inclusions during the ladle process. The model developed by the authors offers potential for control and optimization of the operation of a ladle furnace.

Evolution behaviour and modification mechanism of inclusions in NM500 wear-resistant steel with calcium treatment

“…Since both slag and furnace lining contain MgO and molten steel is not treated with Mg, there is a concentration gradient of Mg content near slag-liquid steel interface and furnace lining-liquid steel interface theoretically, so that the reduced Mg on the slag and furnace lining surface can transfer into molten steel to form the dissolved Mg. The reaction is shown in Equation (18). Mg dissolved in molten steel will further react with Al 2 O 3 inclusions in steel to form MgO•Al 2 O 3 inclusions.…”

“…According to Table 1, thermodynamic calculation and SEM-EDS analysis are widely used to study the formation and modification mechanism of inclusions in different steel grades, the evolution law of compositions, sizes, numbers and morphology characteristics of the different inclusions after calcium treatment in different steel grades [1][2][3]6,8,10,[12][13][14][21][22][23][24][25][26], and the optimization and improvement of calcium treatment process [4,5,9,20,29], as well as the mechanism reducing nozzle nodulation and the degree of tundish stopper erosion with calcium treatment [27,28]. The modification and local concentration of inclusions, rate-controlling step of inclusion modification and change of inclusion compositions with different reaction times in calcium treatment steel can be studied in combination with numerical simulation and kinetic models [7,11,[15][16][17][18][19].…”

Modeling of Ladle Refining Process Considering Mixing and Chemical Reaction

“…Tabatabaei et al [15] 2019 Emperical Double film theory Inclusion transformation kinetics was considered Kumar et al [16] 2019 the thermodynamic databases. [26] The databases are provided by FactSage in the form of a ChemSage file.…”

“…The predicted inclusion development and compositions of steel and slag agreed well with the industrial practice from 210 and 30 ton ladle treatment. Additionally, similar models were also developed by the researchers with the specified targets due to the high efficiency, [9][10][11][12][13][14][15][16][17] as shown in Table 1. 1) Most researchers used commercial software (FactSage, Metsim, ChemApp, and SimuSage) for thermodynamic calculations, whereas the empirical models offer a faster calculation speed.…”

Optimizing Slag Content to Control Ds-Type Inclusions in 10B21 Cold Heading Steel

“…Numerous studies show that refining slag is an important factor influencing nonmetallic inclusion formation in steel. Different refining slag systems can be used to control the morphology, size, and composition of nonmetallic inclusions in steel [10][11][12][13][14][15]. Sui Yafei et al changed the viscosity of the refined slag by changing the content of Al 2 O 3 and CaF in the slag and used the steel slag balance to control the nonmetallic inclusions in the steel, thereby improving the quality of the steel.…”