Growth behavior and kinetics of magnetite during magnetization roasting

The magnetization roasting of hematite with two particle sizes was performed to investigate the growth behavior and kinetics of magnetite. The magnetite exhibited comparable growth trends throughout the magnetization roasting process at different roasting temperatures, and enhancing the roasting temperature can facilitate the growth of magnetite. The nascent magnetite nuclei appeared acicular, predominantly developed along the edges and fissures of the hematite particles before progressively growing inward. Moreover, the temperature stress and magnetite formation led to the loose and porous structure of the nascent magnetite particles. The growth kinetics demonstrated that the growth process of magnetite could be divided into induction period and growth period based on the different growth rates. For the same hematite sample, the growth rate of magnetite in the induction period was lower than that in the growth period. The magnetization roasting of hematite with a smaller particle size may be completed in a shorter time, even if increasing the particle size of hematite can accelerate the growth rate of magnetite. The growth kinetic models were established based on the parabolic law, and the reliability of describing the growth process of magnetite was verified by comparing the predicted values with the experimental values. (c) 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Automated summary

The growth behavior and kinetics of magnetite during the magnetization roasting of hematite with different particle sizes were investigated. The results showed that magnetite exhibited similar growth trends at different roasting temperatures, and increasing the roasting temperature facilitated the growth of magnetite. The growth process of magnetite could be divided into induction period and growth period, and magnetization roasting of hematite with a smaller particle size could be completed in a shorter time.