Investigating the kinetics, thermodynamic properties, and mechanisms of high-temperature oxidation in ferrosilicon alloys

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2024-10, Vol.498, p.155473, Article 155473
• Main Authors: Peng, Hualin, Chen, Lijuan, Wei, Bo, Li, Shuanglong, Yang, Tao, Liu, Kunpeng, Wang, Jianjiang, Abudoureheman, Maierhaba
• Format: Article
• Language: English
• Subjects: Ferrosilicon alloys; Kinetic characteristics; Oxidation reaction mechanism; Parabolic rate law; Thermodynamic feasibility
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2024.155473

[Display omitted] •The oxidation processes of ferrosilicon alloys are primarily influenced by reaction time and reaction temperature, followed by particle size, and adhere to the parabolic law.•The results show that while the E from the VM model is slightly lower than that from the URCM model, both models exhibit a similar trend.•High temperature makes ferrosilicon alloys melt and soften, resulting in the oxidation layers falling off and accelerating oxidation. Ferrosilicon alloys are widely used as a deoxidizer in steelmaking due to their strong oxygen affinity and high deoxidizing ability. However, compared to other deoxidizers, relatively few studies have been conducted on its kinetics, thermodynamics, and reaction mechanisms. This study aims to investigate the oxidation characteristics of ferrosilicon alloys at different particle sizes, reaction temperatures, and reaction times, and to evaluate their oxidation structure and reaction characteristics. To achieve this, we used the response surface methodology (RSM) to establish a multi-factor model. The results show that reaction time and reaction temperature are the primary factors affecting the oxidation rates, followed by particle size. Wagner’s law was used to verify that the change in oxidation mass follows the parabolic rate law and was discussed in relation to other alloys. Additionally, the application of the volumetric model (VM) and the unreacted core model (URCM) in calculating the activation energy (E) was compared to understand the kinetic characteristics of ferrosilicon alloys more comprehensively. Specifically, when the particle size range increases from 0.075–––0.1 mm to 0.3–––0.5 mm, the estimated E of the VM model increases from 81.82 KJ·mol−1 to 87.84 KJ·mol−1. The URCM model’s result increases from 91.53 KJ·mol−1 to 97.21 KJ·mol−1. Additionally, we evaluated the thermodynamic feasibility of ferrosilicon alloys at temperatures ranging from 273.15 K to 1673.15 K using HSC Chemistry software. This paper describes in detail the oxide layer structure and oxidation reaction process of ferrosilicon alloys and proposes an oxidation reaction mechanism, providing a reliable theoretical basis for the application system of ferrosilicon alloys.