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<p>This study systematically investigates the carbochlorination kinetics of pure Al<sub>2</sub>O<sub>3</sub> and SiO<sub>2</sub> via thermodynamic calculation and multi-heating-rate TG–DTG analysis. Kinetic parameters were determined through model-free (FWO and KAS) and model-fitting (Coats–Redfern) methods in accordance with ICTAC kinetics committee recommendations, supported by an iterative correction procedure for accuracy. Results demonstrate a significant kinetic advantage for Al<sub>2</sub>O<sub>3</sub> over SiO<sub>2</sub>, reflected in its lower activation energy (77.49&#xa0;kJ&#xa0;mol<sup>−1</sup>). Al<sub>2</sub>O<sub>3</sub> carbochlorination follows a second-order chemical surface reaction model, controlled by interfacial chemical steps. In contrast, SiO<sub>2</sub> exhibits a higher activation energy (90.28&#xa0;kJ&#xa0;mol<sup>−1</sup>) and is consistent with a shrinking core (volume) model controlled by product-layer diffusion. The work establishes a complete kinetic triplet for each oxide, revealing fundamentally different rate-limiting steps. These findings provide deep mechanistic insights into oxide carbochlorination and offer a reliable kinetic framework for predicting and modeling the behavior of complex aluminosilicate systems under chlorine-containing reactive atmospheres.</p>

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Non-isothermal kinetics and mechanism of carbochlorination of Al2O3 and SiO2: a comparative study by TG–DTG analysis

  • 期刊论文

  • 发表日期：

    2026年7月12日

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  • Xinxin Zhao,
  • Long Wang,
  • Yan Liu,
  • Jiawei Ren,
  • Yutong Hua,
  • Haiyue Xue,
  • Ting-an Zhang

摘要

This study systematically investigates the carbochlorination kinetics of pure Al2O3 and SiO2 via thermodynamic calculation and multi-heating-rate TG–DTG analysis. Kinetic parameters were determined through model-free (FWO and KAS) and model-fitting (Coats–Redfern) methods in accordance with ICTAC kinetics committee recommendations, supported by an iterative correction procedure for accuracy. Results demonstrate a significant kinetic advantage for Al2O3 over SiO2, reflected in its lower activation energy (77.49 kJ mol−1). Al2O3 carbochlorination follows a second-order chemical surface reaction model, controlled by interfacial chemical steps. In contrast, SiO2 exhibits a higher activation energy (90.28 kJ mol−1) and is consistent with a shrinking core (volume) model controlled by product-layer diffusion. The work establishes a complete kinetic triplet for each oxide, revealing fundamentally different rate-limiting steps. These findings provide deep mechanistic insights into oxide carbochlorination and offer a reliable kinetic framework for predicting and modeling the behavior of complex aluminosilicate systems under chlorine-containing reactive atmospheres.