Evolution of Mg–Al-based Inclusions with Changes in Mg Content during Ladle Treatment Based on a Coupled Reaction Model

Abstract

In the steelmaking process, MgAl 2 O 4 spinel inclusions diminish steel qualities and cause nozzle clogging based on the high melting point and low deformation of MgAl 2 O 4. Typically, MgAl 2 O 4 spinel inclusions are generated from Al 2 O 3 inclusions with increasing MgO content, meaning ladle treatment does not represent an equilibrium state. However, complex reactions simultaneously occur between molten steel, slag, inclusions, refractory, and alloying elements during ladle treatment. Therefore, it is necessary to develop a kinetic model to predict compositional changes in molten steel, slag, and the inclusions during ladle treatment. Such a kinetic model must be able to simulate the generation of MgAl 2 O 4 spinel inclusions from Al 2 O 3 to control such inclusions. Additionally, MgAl 2 O 4 spinel inclusions can evolve into MgO-rich inclusions with gradually increasing MgO content in Mg-Al-based inclusions. In this study, we developed an enhanced kinetic model based on a coupled reaction model with the compositional changes in Mg-Albased inclusions. We also investigated the influence of the CaO/SiO 2 ratio in slag on the generation of spinel inclusions under industrial conditions for a 210-ton steel sample.

Evolution of the Inclusion Population During the Processing of Al-killed Steel

“…At the end of LF treatment, the composition of the inclusions is modified by Ca addition to form liquid inclusions of the Al2O3-CaO type [11]. The Ca treatment efficiency seems to depend on the type of inclusions present before the modification treatment, i.e., Al2O3 or Al2O3-MgO inclusions, [5,10,[12][13][14] and the homogenization of dissolved Ca in the liquid bath [15]. In addition, a decrease in temperature occurs progressively in the operations following the LF treatment, i.e., transfer of the ladle to the continuous casting (CC) station and the CC process, and the thermodynamic conditions of the liquid steel-inclusion interactions change and consequently the chemistry of the inclusions can be modified.…”

A Review of Kinetic Model for Production of Highgrade Steel : Part. 2. Complex Reaction Model and Single Reaction Model

“…있다 [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] . 2차 정련의 시뮬레이션 모델은 전술한 논문(part.…”

“…2차 정련의 시뮬레이션 모델은 전술한 논문(part. 1)에 서 설명한 Coupled reaction 모델 기반의 모델들 [5][6][7][8][9][10][11][12][13][14][15] 부터, 2절에서 소개할 EERZ 모델 [16][17][18] , ReSMI 모델 19,20) , Metsim 모델 21) , ICS 모델 22,23) , Kumar 등이 발표한 모델 24) 들로 구 분될 수 있다. 위와 같이 2차 정련의 여러가지 복잡한 반 응들을 고려하고 있는 종합 모델들 외에도, 2차 정련 공정 에서 일어나는 한 가지 반응에 대하여 보고한 단일 반응 모델들 [25][26][27][28][29][30][31][32]35)…”