Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8004218 | Journal of Iron and Steel Research, International | 2017 | 7 Pages |
Abstract
The non-isothermal oxidation experiments of ilmenite concentrate were carried out at various heating rates under air atmosphere by thermogravimetry. The oxidation kinetic model function and kinetic parameters of apparent activation energy (Ea) were evaluated by Málek and Starink methods. The results show that under air atmosphere, the oxidation process of ilmenite concentrate is composed of three stages, and the chemical reaction (G(α) = 1-(1-α)2, where α is the conversion degree) plays an important role in the whole oxidation process. At the first stage (α = 0. 05-0. 30), the oxidation process is controlled gradually by secondary chemical reaction with increasing conversion degree. At the second stage (α = 0.30-0.50), the oxidation process is completely controlled by the secondary chemical reaction (G(α) = 1 - (1 - α)2). At the third stage (α=0. 50 - 0.95), the secondary chemical reaction weakens gradually with increasing conversion degree, and the oxidation process is controlled gradually by a variety of functions; the kinetic equations are G(α)-(1-α)â1 (Ã=10 K · minâ1, where à is heating rate), G(α) = (1 - α) â½ (Ã= 15 - 20 K · minâ1), and G(α) = (1 - α)â2(Ã=25 K · minâ1), respectively. For the whole oxidation process, the activation energies follow a parabolic law with increasing conversion degree, and the average activation energy is 160. 56 kJ · molâ1.
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Ying-yi Zhang, Wei Lv, Xue-wei Lv, Chen-guang Bai, Ke-xi Han, Bing Song,