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<p>The mobility characteristics of molten ash within coke matrices during blast furnace operations substantially influence coke quality parameters, rendering comprehensive investigation of this phenomenon critical for process optimisation in ferrous metallurgy. Although prior studies have demonstrated that TiO<sub>2</sub> reduces polymerization in basic slags, its role in governing the structural evolution of highly acidic, coke-derived molten ash remains poorly understood. Since coke ash typically exhibits characteristics of highly acidic slag systems, this study focuses on the SiO<sub>2</sub>-Al<sub>2</sub>O<sub>3</sub>-CaO-TiO<sub>2</sub> quaternary system. Through integrated molecular dynamics simulations and experimental investigations, we systematically examine TiO<sub>2</sub>’s influence on the structural evolution of molten ash and quantitatively assess its effects on viscosity and flow behaviour. The findings reveal that [SiO<sub>4</sub>] and [AlO<sub>4</sub>] tetrahedra constitute the fundamental structural units within molten ash. As TiO<sub>2</sub> content decreases, the population of [TiO<sub>m</sub>] polyhedral structures diminishes, leading to a progressive simplification of the interconnected network. This structural modification correlates with reduced slag viscosity and enhanced fluidity. Furthermore, synergistic diffusion between Ti and Si atoms in the slag matrix demonstrates pronounced sensitivity to TiO<sub>2</sub> concentration. At 2&#xa0;wt.% TiO<sub>2</sub>, Ti exhibits greater diffusivity than Si. Viscosity reduction with decreasing TiO<sub>2</sub> content coincides with a decline in bridging oxygen species and an increase in non-bridging oxygen populations, indicative of molecular depolymerisation from large clusters to smaller fragments—a phenomenon corroborated by FTIR spectral analysis. These structural alterations suggest that elevated TiO<sub>2</sub> content enhances slag viscosity while concurrently improving coke mechanical strength through modified ash-phase interactions. We address this gap by revealing that TiO<sub>2</sub> modifies network connectivity differently in acidic environments, reducing polymerization by forming [TiO<sub>m</sub>] polyhedra that disrupt Si-O-Al linkages. These findings highlight the compositional dependency of TiO<sub>2</sub>’s structural effects, providing novel insights into optimizing coke performance in blast furnaces.</p>

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Study on the Influence of TiO2 on the Viscosity and Fluidity of Ash Slag of Highly Acidic Coke at High Temperature

  • 期刊论文

  • 发表日期：

    2025年7月10日

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  • Fan Yang,
  • Qingguo Xue,
  • Binbin Lvy,
  • Haibin Zuo,
  • Jingsong Wang

摘要

The mobility characteristics of molten ash within coke matrices during blast furnace operations substantially influence coke quality parameters, rendering comprehensive investigation of this phenomenon critical for process optimisation in ferrous metallurgy. Although prior studies have demonstrated that TiO2 reduces polymerization in basic slags, its role in governing the structural evolution of highly acidic, coke-derived molten ash remains poorly understood. Since coke ash typically exhibits characteristics of highly acidic slag systems, this study focuses on the SiO2-Al2O3-CaO-TiO2 quaternary system. Through integrated molecular dynamics simulations and experimental investigations, we systematically examine TiO2’s influence on the structural evolution of molten ash and quantitatively assess its effects on viscosity and flow behaviour. The findings reveal that [SiO4] and [AlO4] tetrahedra constitute the fundamental structural units within molten ash. As TiO2 content decreases, the population of [TiOm] polyhedral structures diminishes, leading to a progressive simplification of the interconnected network. This structural modification correlates with reduced slag viscosity and enhanced fluidity. Furthermore, synergistic diffusion between Ti and Si atoms in the slag matrix demonstrates pronounced sensitivity to TiO2 concentration. At 2 wt.% TiO2, Ti exhibits greater diffusivity than Si. Viscosity reduction with decreasing TiO2 content coincides with a decline in bridging oxygen species and an increase in non-bridging oxygen populations, indicative of molecular depolymerisation from large clusters to smaller fragments—a phenomenon corroborated by FTIR spectral analysis. These structural alterations suggest that elevated TiO2 content enhances slag viscosity while concurrently improving coke mechanical strength through modified ash-phase interactions. We address this gap by revealing that TiO2 modifies network connectivity differently in acidic environments, reducing polymerization by forming [TiOm] polyhedra that disrupt Si-O-Al linkages. These findings highlight the compositional dependency of TiO2’s structural effects, providing novel insights into optimizing coke performance in blast furnaces.